query: Pro-inflammatory cytokines are up repressed during tumor development.

text: Paraneoplastic thrombocytosis is associated with many solid tumors and often correlates with reduced survival. Recent studies suggest that a pathogenic feed back loop may be operative between platelets and tumor cells, with reciprocal interactions between tumor growth/metastasis and thrombocytosis/platelet activation. Specific molecular pathways have been identified in which tumors can stimulate platelet production and activation; activated platelets can, in turn, promote tumor growth and metastasis. Taken together, these findings provide exciting new potential targets for therapeutic intervention.

title: miR-205 hinders the malignant interplay between prostate cancer cells and associated fibroblasts.

text:
AIMS Tumor microenvironment is a strong determinant for the acquisition of metastatic potential of cancer cells. We have recently demonstrated that cancer-associated fibroblasts (CAFs) elicit a redox-dependent epithelial-mesenchymal transition (EMT) in prostate cancer (PCa) cells, driven by cycloxygenase-2/hypoxia-inducible factor-1 (HIF-1)/nuclear factor-κB pathway and enhancing tumor aggressiveness. Here, we investigated the involvement of microRNAs (miRNAs) in tumor-stroma interplay to identify possible tools to counteract oxidative stress and metastasis dissemination.
 RESULTS We found that miR-205 is the most downmodulated miRNA in PCa cells upon CAF stimulation, due to direct transcriptional repression by HIF-1, a known redox-sensitive transcription factor. Rescue experiments demonstrated that ectopic miR-205 overexpression in PCa cells counteracts CAF-induced EMT, thus impairing enhancement of cell invasion, acquisition of stem cell traits, tumorigenicity, and metastatic dissemination. In addition, miR-205 blocks tumor-driven activation of surrounding fibroblasts by reducing pro-inflammatory cytokine secretion.    INNOVATION Overall, such findings suggest miR-205 as a brake against PCa metastasis by blocking both the afferent and efferent arms of the circuit between tumor cells and associated fibroblasts, thus interrupting the pro-oxidant and pro-inflammatory circuitries engaged by reactive stroma.
 CONCLUSION The evidence that miR-205 replacement in PCa cells is able not only to prevent but also to revert the oxidative/pro-inflammatory axis leading to EMT induced by CAFs sets the rationale for developing miRNA-based approaches to prevent and treat metastatic disease.

title: Reduced Cytokine Release in Ex Vivo Response to Cilengitide and Cetuximab Is a Marker for Improved Survival of Head and Neck Cancer Patients

text: Targeting of αVβ3 and αVβ5 integrins by cilengitide may reduce growth of solid tumors including head and neck squamous cell carcinoma (HNSCC). Preclinical investigations suggest increased activity of cilengitide in combination with other treatment modalities. The only published trial in HNSCC (ADVANTAGE) investigated cisplatin, 5-fluorouracil, and cetuximab (PFE) without or with once (PFE+CIL1W) or twice weekly cilengitide (PFE+CIL2W) in recurrent/metastatic HNSCC. ADVANTAGE showed good tolerability of the cilengitide arms and even lower adverse events (AEs) compared to PFE but not the benefit in overall survival expected based on preclinical data. As we found in the FLAVINO assay, a short-time ex vivo assay for prediction of chemosensitivity, only a subgroup of HNSCC had an increased suppressive effect of cilengitide containing combination therapies on colony formation of epithelial cells (CFec) and release of pro-angiogenetic and pro-inflammatory cytokines, whereas other HNSCC failed to respond. Response to αVβ3 and αVβ5 integrin targeting by cilengitide classifies HNSCC regarding outcome. We present FLAVINO data arguing for further development of cilengitide plus cetuximab in treatment of a subgroup of HNSCC potentially identified by the FLAVINO assay using a set of biomarkers for response evaluation.

title: Downloaded from

title: The Nuclear Effector of Wnt-Signaling, Tcf1, Functions as a T-Cell–Specific Tumor Suppressor for Development of Lymphomas

text: The HMG-box factor Tcf1 is required during T-cell development in the thymus and mediates the nuclear response to Wnt signals. Tcf1(-/-) mice have previously been characterized and show developmental blocks at the CD4-CD8- double negative (DN) to CD4+CD8+ double positive transition. Due to the blocks in T-cell development, Tcf1(-/-) mice normally have a very small thymus. Unexpectedly, a large proportion of Tcf1(-/-) mice spontaneously develop thymic lymphomas with 50% of mice developing a thymic lymphoma/leukemia at the age of 16 wk. These lymphomas are clonal, highly metastatic, and paradoxically show high Wnt signaling when crossed with Wnt reporter mice and have high expression of Wnt target genes Lef1 and Axin2. In wild-type thymocytes, Tcf1 is higher expressed than Lef1, with a predominance of Wnt inhibitory isoforms. Loss of Tcf1 as repressor of Lef1 leads to high Wnt activity and is the initiating event in lymphoma development, which is exacerbated by activating Notch1 mutations. Thus, Notch1 and loss of Tcf1 functionally act as collaborating oncogenic events. Tcf1 deficiency predisposes to the development of thymic lymphomas by ectopic up-regulation of Lef1 due to lack of Tcf1 repressive isoforms and frequently by cooperating activating mutations in Notch1. Tcf1 therefore functions as a T-cell-specific tumor suppressor gene, besides its established role as a Wnt responsive transcription factor. Thus, Tcf1 acts as a molecular switch between proliferative and repressive signals during T-lymphocyte development in the thymus.

title: Inflammatory signaling in human Tuberculosis granulomas is spatially organized

text: Granulomas are the pathological hallmark of tuberculosis (TB). However, their function and mechanisms of formation remain poorly understood. To understand the role of granulomas in TB, we analyzed the proteomes of granulomas from subjects with tuberculosis in an unbiased manner. Using laser-capture microdissection, mass spectrometry and confocal microscopy, we generated detailed molecular maps of human granulomas. We found that the centers of granulomas have a pro-inflammatory environment that is characterized by the presence of antimicrobial peptides, reactive oxygen species and pro-inflammatory eicosanoids. Conversely, the tissue surrounding the caseum has a comparatively anti-inflammatory signature. These findings are consistent across a set of six human subjects and in rabbits. Although the balance between systemic pro- and anti-inflammatory signals is crucial to TB disease outcome, here we find that these signals are physically segregated within each granuloma. From the protein and lipid snapshots of human and rabbit lesions analyzed here, we hypothesize that the pathologic response to TB is shaped by the precise anatomical localization of these inflammatory pathways during the development of the granuloma.

title: Interleukin-17 mRNA expression in blood and CSF mononuclear cells is augmented in multiple sclerosis.

text: Myelin-directed autoimmunity is considered to play a key role in the pathogenesis of multiple sclerosis (MS). Increased production of both pro- and anti-inflammatory cytokines is a common finding in MS. Interleukin-17 (IL-17) is a recently described cytokine produced in humans almost exclusively by activated memory T cells, which can induce the production of proinflammatory cytokines and chemokines from parenchymal cells and macrophages. In situ hybridisation with synthetic oligonucleotide probes was adopted to detect and enumerate IL-17 mRNA expressing mononuclear cells (MNC) in blood and cerebrospinal fluid (CSF) from patients with MS and control individuals. Numbers of IL-17 mRNA expressing blood MNC were higher in patients with MS and acute aseptic meningoencephalitis (AM) compared to healthy individuals. Higher numbers of IL-17 mRNA expressing blood MNC were detected in MS patients examined during clinical exacerbation compared to remission. Patients with MS had higher numbers of IL-17 mRNA expressing MNC in CSF compared to blood. This increase in numbers of IL-17 mRNA expressing MNC in CSF was not observed in patients with AM. Our results thus demonstrate increased numbers of IL-17 mRNA expressing MNC in MS with higher numbers in CSF than blood, and with the highest numbers in blood during clinical exacerbations.

title: Deficiency of Interleukin-15 Confers Resistance to Obesity by Diminishing Inflammation and Enhancing the Thermogenic Function of Adipose Tissues

text:
OBJECTIVE IL-15 is an inflammatory cytokine secreted by many cell types. IL-15 is also produced during physical exercise by skeletal muscle and has been reported to reduce weight gain in mice. Contrarily, our findings on IL-15 knockout (KO) mice indicate that IL-15 promotes obesity. The aim of this study is to investigate the mechanisms underlying the pro-obesity role of IL-15 in adipose tissues.
 METHODS Control and IL-15 KO mice were maintained on high fat diet (HFD) or normal control diet. After 16 weeks, body weight, adipose tissue and skeletal mass, serum lipid levels and gene/protein expression in the adipose tissues were evaluated. The effect of IL-15 on thermogenesis and oxygen consumption was also studied in primary cultures of adipocytes differentiated from mouse preadipocyte and human stem cells.
 RESULTS Our results show that IL-15 deficiency prevents diet-induced weight gain and accumulation of lipids in visceral and subcutaneous white and brown adipose tissues. Gene expression analysis also revealed elevated expression of genes associated with adaptive thermogenesis in the brown and subcutaneous adipose tissues of IL-15 KO mice. Accordingly, oxygen consumption was increased in the brown adipocytes from IL-15 KO mice. In addition, IL-15 KO mice showed decreased expression of pro-inflammatory mediators in their adipose tissues.
 CONCLUSIONS Absence of IL-15 results in decreased accumulation of fat in the white adipose tissues and increased lipid utilization via adaptive thermogenesis. IL-15 also promotes inflammation in adipose tissues that could sustain chronic inflammation leading to obesity-associated metabolic syndrome.

title: Mechanisms linking obesity to insulin resistance and type 2 diabetes

text: Obesity is associated with an increased risk of developing insulin resistance and type 2 diabetes. In obese individuals, adipose tissue releases increased amounts of non-esterified fatty acids, glycerol, hormones, pro-inflammatory cytokines and other factors that are involved in the development of insulin resistance. When insulin resistance is accompanied by dysfunction of pancreatic islet β-cells — the cells that release insulin — failure to control blood glucose levels results. Abnormalities in β-cell function are therefore critical in defining the risk and development of type 2 diabetes. This knowledge is fostering exploration of the molecular and genetic basis of the disease and new approaches to its treatment and prevention.

title: NETs are a source of citrullinated autoantigens and stimulate inflammatory responses in rheumatoid arthritis.

text: The early events leading to the development of rheumatoid arthritis (RA) remain unclear, but formation of autoantibodies to citrullinated protein antigens (ACPAs) is considered a key pathogenic event. Neutrophils isolated from patients with various autoimmune diseases display enhanced neutrophil extracellular trap (NET) formation, a phenomenon that exposes autoantigens in the context of immunostimulatory molecules. We investigated whether aberrant NETosis occurs in RA, determined its triggers, and examined its deleterious inflammatory consequences. Enhanced NETosis was observed in circulating and RA synovial fluid neutrophils compared to neutrophils from healthy controls and from patients with osteoarthritis (OA). Further, netting neutrophils infiltrated RA synovial tissue, rheumatoid nodules, and skin. NETosis correlated with ACPA presence and levels and with systemic inflammatory markers. RA sera and immunoglobulin fractions from RA patients with high levels of ACPA and/or rheumatoid factor significantly enhanced NETosis, and the NETs induced by these autoantibodies displayed distinct protein content. Indeed, during NETosis, neutrophils externalized the citrullinated autoantigens implicated in RA pathogenesis, and anti-citrullinated vimentin antibodies potently induced NET formation. Moreover, the inflammatory cytokines interleukin-17A (IL-17A) and tumor necrosis factor-α (TNF-α) induced NETosis in RA neutrophils. In turn, NETs significantly augmented inflammatory responses in RA and OA synovial fibroblasts, including induction of IL-6, IL-8, chemokines, and adhesion molecules. These observations implicate accelerated NETosis in RA pathogenesis, through externalization of citrullinated autoantigens and immunostimulatory molecules that may promote aberrant adaptive and innate immune responses in the joint and in the periphery, and perpetuate pathogenic mechanisms in this disease.

title: In vitro characterization of the anti-PD-1 antibody nivolumab, BMS-936558, and in vivo toxicology in non-human primates.

text: The programmed death-1 (PD-1) receptor serves as an immunologic checkpoint, limiting bystander tissue damage and preventing the development of autoimmunity during inflammatory responses. PD-1 is expressed by activated T cells and downmodulates T-cell effector functions upon binding to its ligands, PD-L1 and PD-L2, on antigen-presenting cells. In patients with cancer, the expression of PD-1 on tumor-infiltrating lymphocytes and its interaction with the ligands on tumor and immune cells in the tumor microenvironment undermine antitumor immunity and support its rationale for PD-1 blockade in cancer immunotherapy. This report details the development and characterization of nivolumab, a fully human IgG4 (S228P) anti-PD-1 receptor-blocking monoclonal antibody. Nivolumab binds to PD-1 with high affinity and specificity, and effectively inhibits the interaction between PD-1 and its ligands. In vitro assays demonstrated the ability of nivolumab to potently enhance T-cell responses and cytokine production in the mixed lymphocyte reaction and superantigen or cytomegalovirus stimulation assays. No in vitro antibody-dependent cell-mediated or complement-dependent cytotoxicity was observed with the use of nivolumab and activated T cells as targets. Nivolumab treatment did not induce adverse immune-related events when given to cynomolgus macaques at high concentrations, independent of circulating anti-nivolumab antibodies where observed. These data provide a comprehensive preclinical characterization of nivolumab, for which antitumor activity and safety have been demonstrated in human clinical trials in various solid tumors.

title: Wedelolactone exhibits anti-fibrotic effects on human hepatic stellate cell line LX-2.

text: Wedelolactone is a major coumarin of Eclipta prostrata, which is used for preventing liver damage. However the effects of wedelolactone on hepatic fibrosis remained unexplored. The purpose of this study was to demonstrate the anti-fibrotic effects of wedelolactone on activated human hepatic stellate cell (HSC) line LX-2 and the possible underlying mechanisms by means of MTT assay, Hoechst staining, as well as real-time quantitative PCR and western blot. The results showed that wedelolactone reduced the cellular viability of LX-2 in a time and dose-dependent manner. After treatment of wedelolactone, the expressions of collagen I and α-smooth muscle actin, two biomarkers of LX-2 activation, were remarkably decreased. The apoptosis of LX-2 cells was induced by wedelolactone accompanied with the decreasing expression of anti-apoptotic Bcl-2 and increasing expression of pro-apoptotic Bax. In addition, phosphorylated status of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was up-regulated, but not in p38. Moreover, wedelolactone significantly repressed the level of phosphorylated inhibitor of nuclear factor κB (IκB) and p65 in nucleus in spite of tumor necrosis factor-α stimulation. In conclusion, wedelolactone could significantly inhibit the activation of LX-2 cells, the underlying mechanisms of which included inducing Bcl-2 family involved apoptosis, up-regulating phosphorylated status of ERK and JNK expressions, and inhibiting nuclear factor-κB (NF-κB) mediated activity. Wedelolactone might present as a useful tool for the prevention and treatment of hepatic fibrosis.

title: High-mobility group box-1 protein induces osteogenic phenotype changes in aortic valve interstitial cells.

text:
OBJECTIVES Calcific aortic valve (AV) disease is known to be an inflammation-related process. High-mobility group box-1 (HMGB1) protein and Toll-like receptor 4 (TLR4) have been reported to participate in several inflammatory diseases. The purpose of the present study was to determine whether the HMGB1-TLR4 axis is involved in calcific AV disease, and to evaluate the effect of HMGB1, and its potential mechanisms, on the pro-osteogenic phenotype change of valvular interstitial cells (VICs).
 METHODS Expression of HMGB1 and TLR4 in human calcific AVs was evaluated using immunohistochemical staining and immunoblotting. Cultured VICs were used as an in vitro model. The VICs were stimulated with HMGB1 for analysis, with versus without TLR4 small interfering ribonucleic acid (siRNA), c-Jun N-terminal kinase mitogen-activated protein kinase (JNK MAPK), and nuclear factor kappa-B (NF-κB) inhibitors.
 RESULTS Enhanced accumulation of HMGB1 and TLR4 was observed in calcific valves. Moreover, we found that HMGB1 induced high levels of pro-inflammatory cytokine production and promoted the osteoblastic differentiation and calcification of VICs. In addition, HMGB1 induced phosphorylation of JNK MAPK and NF-κB. However, these effects were markedly suppressed by siRNA silencing of TLR4. In addition, blockade of JNK MAPK and NF-κB phosphorylation prohibited HMGB1-induced production of pro-osteogenic factors, and mineralization of VICs.
 CONCLUSIONS The HMGB1 protein may promote osteoblastic differentiation and calcification of VICs, through the TLR4-JNK-NF-κB signaling pathway.

title: Inflammatory cytokines in depression: neurobiological mechanisms and therapeutic implications.

text: Mounting evidence indicates that inflammatory cytokines contribute to the development of depression in both medically ill and medically healthy individuals. Cytokines are important for development and normal brain function, and have the ability to influence neurocircuitry and neurotransmitter systems to produce behavioral alterations. Acutely, inflammatory cytokine administration or activation of the innate immune system produces adaptive behavioral responses that promote conservation of energy to combat infection or recovery from injury. However, chronic exposure to elevated inflammatory cytokines and persistent alterations in neurotransmitter systems can lead to neuropsychiatric disorders and depression. Mechanisms of cytokine behavioral effects involve activation of inflammatory signaling pathways in the brain that results in changes in monoamine, glutamate, and neuropeptide systems, and decreases in growth factors, such as brain-derived neurotrophic factor. Furthermore, inflammatory cytokines may serve as mediators of both environmental (e.g. childhood trauma, obesity, stress, and poor sleep) and genetic (functional gene polymorphisms) factors that contribute to depression's development. This review explores the idea that specific gene polymorphisms and neurotransmitter systems can confer protection from or vulnerability to specific symptom dimensions of cytokine-related depression. Additionally, potential therapeutic strategies that target inflammatory cytokine signaling or the consequences of cytokines on neurotransmitter systems in the brain to prevent or reverse cytokine effects on behavior are discussed.


query: Progerin induces premature aging in stem cells.

title: Human iPSC-based modeling of late-onset disease via progerin-induced aging.

text: Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) resets their identity back to an embryonic age and, thus, presents a significant hurdle for modeling late-onset disorders. In this study, we describe a strategy for inducing aging-related features in human iPSC-derived lineages and apply it to the modeling of Parkinson's disease (PD). Our approach involves expression of progerin, a truncated form of lamin A associated with premature aging. We found that expression of progerin in iPSC-derived fibroblasts and neurons induces multiple aging-related markers and characteristics, including dopamine-specific phenotypes such as neuromelanin accumulation. Induced aging in PD iPSC-derived dopamine neurons revealed disease phenotypes that require both aging and genetic susceptibility, such as pronounced dendrite degeneration, progressive loss of tyrosine hydroxylase (TH) expression, and enlarged mitochondria or Lewy-body-precursor inclusions. Thus, our study suggests that progerin-induced aging can be used to reveal late-onset age-related disease features in hiPSC-based disease models.

title: Genotoxic Stress Abrogates Renewal of Melanocyte Stem Cells by Triggering Their Differentiation

text: Somatic stem cell depletion due to the accumulation of DNA damage has been implicated in the appearance of aging-related phenotypes. Hair graying, a typical sign of aging in mammals, is caused by the incomplete maintenance of melanocyte stem cells (MSCs) with age. Here, we report that irreparable DNA damage, as caused by ionizing radiation, abrogates renewal of MSCs in mice. Surprisingly, the DNA-damage response triggers MSC differentiation into mature melanocytes in the niche, rather than inducing their apoptosis or senescence. The resulting MSC depletion leads to irreversible hair graying. Furthermore, deficiency of Ataxia-telangiectasia mutated (ATM), a central transducer kinase of the DNA-damage response, sensitizes MSCs to ectopic differentiation, demonstrating that the kinase protects MSCs from their premature differentiation by functioning as a "stemness checkpoint" to maintain the stem cell quality and quantity.

title: Deletion of the developmentally essential gene ATR in adult mice leads to age-related phenotypes and stem cell loss.

text: Developmental abnormalities, cancer, and premature aging each have been linked to defects in the DNA damage response (DDR). Mutations in the ATR checkpoint regulator cause developmental defects in mice (pregastrulation lethality) and humans (Seckel syndrome). Here we show that eliminating ATR in adult mice leads to defects in tissue homeostasis and the rapid appearance of age-related phenotypes, such as hair graying, alopecia, kyphosis, osteoporosis, thymic involution, fibrosis, and other abnormalities. Histological and genetic analyses indicate that ATR deletion causes acute cellular loss in tissues in which continuous cell proliferation is required for maintenance. Importantly, thymic involution, alopecia, and hair graying in ATR knockout mice were associated with dramatic reductions in tissue-specific stem and progenitor cells and exhaustion of tissue renewal and homeostatic capacity. In aggregate, these studies suggest that reduced regenerative capacity in adults via deletion of a developmentally essential DDR gene is sufficient to cause the premature appearance of age-related phenotypes.

title: Human oocytes reprogram adult somatic nuclei of a type 1 diabetic to diploid pluripotent stem cells

text: The transfer of somatic cell nuclei into oocytes can give rise to pluripotent stem cells that are consistently equivalent to embryonic stem cells, holding promise for autologous cell replacement therapy. Although methods to induce pluripotent stem cells from somatic cells by transcription factors are widely used in basic research, numerous differences between induced pluripotent stem cells and embryonic stem cells have been reported, potentially affecting their clinical use. Because of the therapeutic potential of diploid embryonic stem-cell lines derived from adult cells of diseased human subjects, we have systematically investigated the parameters affecting efficiency of blastocyst development and stem-cell derivation. Here we show that improvements to the oocyte activation protocol, including the use of both kinase and translation inhibitors, and cell culture in the presence of histone deacetylase inhibitors, promote development to the blastocyst stage. Developmental efficiency varied between oocyte donors, and was inversely related to the number of days of hormonal stimulation required for oocyte maturation, whereas the daily dose of gonadotropin or the total number of metaphase II oocytes retrieved did not affect developmental outcome. Because the use of concentrated Sendai virus for cell fusion induced an increase in intracellular calcium concentration, causing premature oocyte activation, we used diluted Sendai virus in calcium-free medium. Using this modified nuclear transfer protocol, we derived diploid pluripotent stem-cell lines from somatic cells of a newborn and, for the first time, an adult, a female with type 1 diabetes.

title: Senescent growth arrest in mesenchymal stem cells is bypassed by Wip1-mediated downregulation of intrinsic stress signaling pathways.

text: Human mesenchymal stem cells (hMSCs) have been widely studied as a source of primary adult stem cells for cell therapy because of their multidifferentiation potential; however, the growth arrest (also known as "premature senescence") often found in hMSCs cultured in vitro has been a major obstacle to the in-depth characterization of these cells. In addition, the inability to maintain constant cell growth hampers the development of additional genetic modifications aimed at achieving desired levels of differentiation to specific tissues; however, the molecular mechanisms that govern this phenomenon remain unclear, with the exception of a few studies demonstrating that induction of p16INK4a is responsible for this senescence-like event. Here, we observed that the premature growth arrest in hMSCs occurs in parallel with the induction of p16INK4a, following abrogation of inhibitory phosphorylation of retinoblastoma protein. These stress responses were concurrent with increased formation of reactive oxygen species (ROSs) from mitochondria and increased p38 mitogen-activated protein kinase (MAPK) activity. The introduction of Wip1 (wild-type p53 inducible phosphatase-1), a well-studied stress modulator, significantly lowered p16INK4a expression and led to p38 MAPK inactivation, although it failed to affect the levels of ROSs. Moreover, the suppression of stress responses by Wip1 apparently extended the life span of hMSCs, compared with control conditions, while maintaining their multilineage differentiation potential. Based on these results, we suggest that senescent growth arrest in hMSCs may result from activation of stress signaling pathways and consequent onset of stress responses, due in part to ROS production during prolonged in vitro culture.

title: Prox1 Is Required for Granule Cell Maturation and Intermediate Progenitor Maintenance During Brain Neurogenesis

text: The dentate gyrus has an important role in learning and memory, and adult neurogenesis in the subgranular zone of the dentate gyrus may play a role in the acquisition of new memories. The homeobox gene Prox1 is expressed in the dentate gyrus during embryonic development and adult neurogenesis. Here we show that Prox1 is necessary for the maturation of granule cells in the dentate gyrus during development and for the maintenance of intermediate progenitors during adult neurogenesis. We also demonstrate that Prox1-expressing intermediate progenitors are required for adult neural stem cell self-maintenance in the subgranular zone; thus, we have identified a previously unknown non-cell autonomous regulatory feedback mechanism that controls adult neurogenesis in this region of the mammalian brain. Finally, we show that the ectopic expression of Prox1 induces premature differentiation of neural stem cells.

title: Cerebral organoids model human brain development and microcephaly

text: The complexity of the human brain has made it difficult to study many brain disorders in model organisms, highlighting the need for an in vitro model of human brain development. Here we have developed a human pluripotent stem cell-derived three-dimensional organoid culture system, termed cerebral organoids, that develop various discrete, although interdependent, brain regions. These include a cerebral cortex containing progenitor populations that organize and produce mature cortical neuron subtypes. Furthermore, cerebral organoids are shown to recapitulate features of human cortical development, namely characteristic progenitor zone organization with abundant outer radial glial stem cells. Finally, we use RNA interference and patient-specific induced pluripotent stem cells to model microcephaly, a disorder that has been difficult to recapitulate in mice. We demonstrate premature neuronal differentiation in patient organoids, a defect that could help to explain the disease phenotype. Together, these data show that three-dimensional organoids can recapitulate development and disease even in this most complex human tissue.

title: Metabolic analysis of senescent human fibroblasts reveals a role for AMP in cellular senescence.

text: Cellular senescence is considered a major tumour-suppressor mechanism in mammals, and many oncogenic insults, such as the activation of the ras proto-oncogene, trigger initiation of the senescence programme. Although it was shown that activation of the senescence programme involves the up-regulation of cell-cycle regulators such as the inhibitors of cyclin-dependent kinases p16INK4A and p21CIP-1, the mechanisms underlying the senescence response remain to be resolved. In the case of stress-induced premature senescence, reactive oxygen species are considered important intermediates contributing to the phenotype. Moreover, distinct alterations of the cellular carbohydrate metabolism are known to contribute to oncogenic transformation, as is best documented for the phenomenon of aerobic glycolysis. These findings suggest that metabolic alterations are involved in tumourigenesis and tumour suppression; however, little is known about the metabolic pathways that contribute to these processes. Using the human fibroblast model of in vitro senescence, we analysed age-dependent changes in the cellular carbohydrate metabolism. Here we show that senescent fibroblasts enter into a metabolic imbalance, associated with a strong reduction in the levels of ribonucleotide triphosphates, including ATP, which are required for nucleotide biosynthesis and hence proliferation. ATP depletion in senescent fibroblasts is due to dysregulation of glycolytic enzymes, and finally leads to a drastic increase in cellular AMP, which is shown here to induce premature senescence. These results suggest that metabolic regulation plays an important role during cellular senescence and hence tumour suppression.

title: Reversal of the cellular phenotype in the premature aging disease Hutchinson-Gilford progeria syndrome

text: Hutchinson-Gilford progeria syndrome (HGPS) is a childhood premature aging disease caused by a spontaneous point mutation in lamin A (encoded by LMNA), one of the major architectural elements of the mammalian cell nucleus. The HGPS mutation activates an aberrant cryptic splice site in LMNA pre-mRNA, leading to synthesis of a truncated lamin A protein and concomitant reduction in wild-type lamin A. Fibroblasts from individuals with HGPS have severe morphological abnormalities in nuclear envelope structure. Here we show that the cellular disease phenotype is reversible in cells from individuals with HGPS. Introduction of wild-type lamin A protein does not rescue the cellular disease symptoms. The mutant LMNA mRNA and lamin A protein can be efficiently eliminated by correction of the aberrant splicing event using a modified oligonucleotide targeted to the activated cryptic splice site. Upon splicing correction, HGPS fibroblasts assume normal nuclear morphology, the aberrant nuclear distribution and cellular levels of lamina-associated proteins are rescued, defects in heterochromatin-specific histone modifications are corrected and proper expression of several misregulated genes is reestablished. Our results establish proof of principle for the correction of the premature aging phenotype in individuals with HGPS.

title: Ovarian Surface Epithelium in Patients with Severe Ovarian Infertility: A Potential Source of Cells Expressing Markers of Pluripotent/Multipotent Stem Cells

text: The aim of this study was to confirm the presence of stem cells in the ovarian surface epithelium of patients with premature ovarian failure and no mature follicles and oocytes. In these patients, small round cells of unknown origin expressing SOX-2 marker of pluripotency were observed among the epithelial cells just after the ovarian surface epithelium scraping. These cells were an integral part of the ovarian surface epithelium. When the scraped cells were cultured in a medium with added follicular fluid to provide some ovarian niche, primitive oocyte-like cells and typical round-shaped cell clusters positively stained on alkaline phosphatase, and markers of pluripotency, such as SOX-2 and SSEA-4, were developed. These markers were expressed early and also later in the culture. Single oocyte-like cells expressed genes OCT4A, SOX-2, NANOG, NANOS, STELLA, CD9, LIN28, KLF4, GDF3, and MYC, characteristic for pluripotent stem cells. The results of this study confirmed the presence of putative stem cells in the ovarian surface epithelium of these patients and provided some basis to create a stem cell line in the future.

title: Chromatin signatures of pluripotent cell lines.

text: Epigenetic genome modifications are thought to be important for specifying the lineage and developmental stage of cells within a multicellular organism. Here, we show that the epigenetic profile of pluripotent embryonic stem cells (ES) is distinct from that of embryonic carcinoma cells, haematopoietic stem cells (HSC) and their differentiated progeny. Silent, lineage-specific genes replicated earlier in pluripotent cells than in tissue-specific stem cells or differentiated cells and had unexpectedly high levels of acetylated H3K9 and methylated H3K4. Unusually, in ES cells these markers of open chromatin were also combined with H3K27 trimethylation at some non-expressed genes. Thus, pluripotency of ES cells is characterized by a specific epigenetic profile where lineage-specific genes may be accessible but, if so, carry repressive H3K27 trimethylation modifications. H3K27 methylation is functionally important for preventing expression of these genes in ES cells as premature expression occurs in embryonic ectoderm development (Eed)-deficient ES cells. Our data suggest that lineage-specific genes are primed for expression in ES cells but are held in check by opposing chromatin modifications.

title: Changes in the prevalence of cerebral palsy for children born very prematurely within a population-based program over 30 years.

text:
CONTEXT Although cerebral palsy (CP) among extremely premature infants has been reported as a major morbidity outcome, there are difficulties comparing published CP rates from many sites over various birth years.
 OBJECTIVE To assess the changes in population-based, gestational age-specific prevalence rates of CP among extremely premature infants over 30 years.
 DESIGN Prospective population-based longitudinal outcome study.
 SETTING AND PARTICIPANTS In Northern Alberta, 2318 infants 20 to 27 weeks' gestational age with birth weights of 500 to 1249 g were liveborn from 1974 through 2003. By 2 years of age, 1437 (62%) had died, 23 (1%) were lost to follow-up, and 858 (37%) had received multidisciplinary neurodevelopmental assessment.
 MAIN OUTCOME MEASURE Population-based prevalence rates of CP were determined. Logistic regression with linear spline was used to assess changes in CP prevalence over time.
 RESULTS At age 2 years, 122 (14.2%) of 858 survivors had CP. This diagnosis was confirmed for each child by age 3 years or older. Among those whose gestational age was 20 to 25 weeks, population-based survival increased from 4% to 31% (P<.001), while CP prevalence per 1000 live births increased monotonically from 0 to 110 until the years 1992-1994 (P<.001) and decreased thereafter to 22 in the years 2001-2003 (P<.001). Among those whose gestational age was 26 to 27 weeks, population-based survival increased from 23% to between 75% and 80% (P<.001), while CP prevalence per 1000 live births increased monotonically from 15 to 155 until the years 1992-1994 (P<.001) and then decreased to 16 in the years 2001-2003 (P<.001). For all survivors born in the years 2001-2003, CP prevalence was 19 per 1000 live births.
 CONCLUSION Population-based CP prevalence rates for children whose gestational age was 20 to 27 weeks and whose birth weight ranged from 500 to 1249 g show steady reductions in the last decade with stable or reducing mortality, reversing trends prior to 1992-1994.

title: Lamin A-dependent nuclear defects in human aging.

text: Mutations in the nuclear structural protein lamin A cause the premature aging syndrome Hutchinson-Gilford progeria (HGPS). Whether lamin A plays any role in normal aging is unknown. We show that the same molecular mechanism responsible for HGPS is active in healthy cells. Cell nuclei from old individuals acquire defects similar to those of HGPS patient cells, including changes in histone modifications and increased DNA damage. Age-related nuclear defects are caused by sporadic use, in healthy individuals, of the same cryptic splice site in lamin A whose constitutive activation causes HGPS. Inhibition of this splice site reverses the nuclear defects associated with aging. These observations implicate lamin A in physiological aging.

title: Delayed and Accelerated Aging Share Common Longevity Assurance Mechanisms

text: Mutant dwarf and calorie-restricted mice benefit from healthy aging and unusually long lifespan. In contrast, mouse models for DNA repair-deficient progeroid syndromes age and die prematurely. To identify mechanisms that regulate mammalian longevity, we quantified the parallels between the genome-wide liver expression profiles of mice with those two extremes of lifespan. Contrary to expectation, we find significant, genome-wide expression associations between the progeroid and long-lived mice. Subsequent analysis of significantly over-represented biological processes revealed suppression of the endocrine and energy pathways with increased stress responses in both delayed and premature aging. To test the relevance of these processes in natural aging, we compared the transcriptomes of liver, lung, kidney, and spleen over the entire murine adult lifespan and subsequently confirmed these findings on an independent aging cohort. The majority of genes showed similar expression changes in all four organs, indicating a systemic transcriptional response with aging. This systemic response included the same biological processes that are triggered in progeroid and long-lived mice. However, on a genome-wide scale, transcriptomes of naturally aged mice showed a strong association to progeroid but not to long-lived mice. Thus, endocrine and metabolic changes are indicative of "survival" responses to genotoxic stress or starvation, whereas genome-wide associations in gene expression with natural aging are indicative of biological age, which may thus delineate pro- and anti-aging effects of treatments aimed at health-span extension.

title: p16INK4A is a robust in vivo biomarker of cellular aging in human skin.

text: The cell-cycle regulating gene, p16INK4A, encoding an inhibitor of cyclin-dependent kinases 4 and 6, is considered to play an important role in cellular aging and in premature senescence. Although there is an age-dependent increase of p16INK4A expression in human fibroblast senescence in vitro, no data are available regarding the age dependency of p16INK4A in vivo. To determine whether p16INK4A expression in human skin correlates with donor age, p16INK4A expression was analyzed by immunohistochemistry as well as the expression of the p16INK4A repressor BMI1. Samples from the age groups 0-20, 21-70, and 71-95 years were selected from a bank of healthy human skin. We show that the number of p16INK4A positive cells is significantly higher in elderly individuals compared to the younger age groups. The number of p16INK4A positive cells was found to be increased in both epidermis and dermis, compartments with strictly different proliferative activities. BMI1 gene expression was significantly down-regulated with increasing donor age, whereas no striking age differences were observed for Ki67. In immunofluorescence co-expression studies, Ki67-positive cells were negative for p16INK4A and BMI1-expressing cells also stained negatively for Ki67. In conclusion, we provide for the first time evidence that p16INK4A expression directly correlates with chronological aging of human skin in vivo. p16INK4A therefore is a biomarker for human aging in vivo. The data reported here suggest a model for changes in regulatory gene expression that drive aging in human skin.

title: A functionally characterized test set of human induced pluripotent stem cells

text: Human induced pluripotent stem cells (iPSCs) present exciting opportunities for studying development and for in vitro disease modeling. However, reported variability in the behavior of iPSCs has called their utility into question. We established a test set of 16 iPSC lines from seven individuals of varying age, sex and health status, and extensively characterized the lines with respect to pluripotency and the ability to terminally differentiate. Under standardized procedures in two independent laboratories, 13 of the iPSC lines gave rise to functional motor neurons with a range of efficiencies similar to that of human embryonic stem cells (ESCs). Although three iPSC lines were resistant to neural differentiation, early neuralization rescued their performance. Therefore, all 16 iPSC lines passed a stringent test of differentiation capacity despite variations in karyotype and in the expression of early pluripotency markers and transgenes. This iPSC and ESC test set is a robust resource for those interested in the basic biology of stem cells and their applications.

title: Quiescent and active hippocampal neural stem cells with distinct morphologies respond selectively to physiological and pathological stimuli and aging.

text: New neurons are generated in the adult hippocampus throughout life by neural stem/progenitor cells (NSCs), and neurogenesis is a plastic process responsive to external stimuli. We show that canonical Notch signaling through RBP-J is required for hippocampal neurogenesis. Notch signaling distinguishes morphologically distinct Sox2(+) NSCs, and within these pools subpopulations can shuttle between mitotically active or quiescent. Radial and horizontal NSCs respond selectively to neurogenic stimuli. Physical exercise activates the quiescent radial population whereas epileptic seizures induce expansion of the horizontal NSC pool. Surprisingly, reduced neurogenesis correlates with a loss of active horizontal NSCs in aged mice rather than a total loss of stem cells, and the transition to a quiescent state is reversible to rejuvenate neurogenesis in the brain. The discovery of multiple NSC populations with Notch dependence but selective responses to stimuli and reversible quiescence has important implications for the mechanisms of adaptive learning and also for regenerative therapy.

title: Oxymetholone Therapy of Fanconi Anemia Suppresses Osteopontin Transcription and Induces Hematopoietic Stem Cell Cycling

text: Androgens are widely used for treating Fanconi anemia (FA) and other human bone marrow failure syndromes, but their mode of action remains incompletely understood. Aged Fancd2(-/-) mice were used to assess the therapeutic efficacy of oxymetholone (OXM) and its mechanism of action. Eighteen-month-old Fancd2(-/-) mice recapitulated key human FA phenotypes, including reduced bone marrow cellularity, red cell macrocytosis, and peripheral pancytopenia. As in humans, chronic OXM treatment significantly improved these hematological parameters and stimulated the proliferation of hematopoietic stem and progenitor cells. RNA-Seq analysis implicated downregulation of osteopontin as an important potential mechanism for the drug's action. Consistent with the increased stem cell proliferation, competitive repopulation assays demonstrated that chronic OXM therapy eventually resulted in stem cell exhaustion. These results expand our knowledge of the regulation of hematopoietic stem cell proliferation and have direct clinical implications for the treatment of bone marrow failure.

title: Mechanism and Regulation of DNA-Protein Crosslink Repair by the DNA-Dependent Metalloprotease SPRTN

text: Covalent DNA-protein crosslinks (DPCs) are toxic DNA lesions that interfere with essential chromatin transactions, such as replication and transcription. Little was known about DPC-specific repair mechanisms until the recent identification of a DPC-processing protease in yeast. The existence of a DPC protease in higher eukaryotes is inferred from data in Xenopus laevis egg extracts, but its identity remains elusive. Here we identify the metalloprotease SPRTN as the DPC protease acting in metazoans. Loss of SPRTN results in failure to repair DPCs and hypersensitivity to DPC-inducing agents. SPRTN accomplishes DPC processing through a unique DNA-induced protease activity, which is controlled by several sophisticated regulatory mechanisms. Cellular, biochemical, and structural studies define a DNA switch triggering its protease activity, a ubiquitin switch controlling SPRTN chromatin accessibility, and regulatory autocatalytic cleavage. Our data also provide a molecular explanation on how SPRTN deficiency causes the premature aging and cancer predisposition disorder Ruijs-Aalfs syndrome.

title: Epigenetic Control of Stem Cell Potential during Homeostasis, Aging, and Disease.

text: Stem cell decline is an important cellular driver of aging-associated pathophysiology in multiple tissues. Epigenetic regulation is central to establishing and maintaining stem cell function, and emerging evidence indicates that epigenetic dysregulation contributes to the altered potential of stem cells during aging. Unlike terminally differentiated cells, the impact of epigenetic dysregulation in stem cells is propagated beyond self; alterations can be heritably transmitted to differentiated progeny, in addition to being perpetuated and amplified within the stem cell pool through self-renewal divisions. This Review focuses on recent studies examining epigenetic regulation of tissue-specific stem cells in homeostasis, aging, and aging-related disease.


query: Propriospinal interneurons that play a role in the plastic reorganization of spinal circuits are integral for recovery from spinal cord injury.

title: Recovery of supraspinal control of stepping via indirect propriospinal relay connections after spinal cord injury

text: Spinal cord injuries (SCIs) in humans and experimental animals are often associated with varying degrees of spontaneous functional recovery during the first months after injury. Such recovery is widely attributed to axons spared from injury that descend from the brain and bypass incomplete lesions, but its mechanisms are uncertain. To investigate the neural basis of spontaneous recovery, we used kinematic, physiological and anatomical analyses to evaluate mice with various combinations of spatially and temporally separated lateral hemisections with or without the excitotoxic ablation of intrinsic spinal cord neurons. We show that propriospinal relay connections that bypass one or more injury sites are able to mediate spontaneous functional recovery and supraspinal control of stepping, even when there has been essentially total and irreversible interruption of long descending supraspinal pathways in mice. Our findings show that pronounced functional recovery can occur after severe SCI without the maintenance or regeneration of direct projections from the brain past the lesion and can be mediated by the reorganization of descending and propriospinal connections. Targeting interventions toward augmenting the remodeling of relay connections may provide new therapeutic strategies to bypass lesions and restore function after SCI and in other conditions such as stroke and multiple sclerosis.

title: Modulation of the proteoglycan receptor PTPσ promotes recovery after spinal cord injury

text: Contusive spinal cord injury leads to a variety of disabilities owing to limited neuronal regeneration and functional plasticity. It is well established that an upregulation of glial-derived chondroitin sulphate proteoglycans (CSPGs) within the glial scar and perineuronal net creates a barrier to axonal regrowth and sprouting. Protein tyrosine phosphatase σ (PTPσ), along with its sister phosphatase leukocyte common antigen-related (LAR) and the nogo receptors 1 and 3 (NgR), have recently been identified as receptors for the inhibitory glycosylated side chains of CSPGs. Here we find in rats that PTPσ has a critical role in converting growth cones into a dystrophic state by tightly stabilizing them within CSPG-rich substrates. We generated a membrane-permeable peptide mimetic of the PTPσ wedge domain that binds to PTPσ and relieves CSPG-mediated inhibition. Systemic delivery of this peptide over weeks restored substantial serotonergic innervation to the spinal cord below the level of injury and facilitated functional recovery of both locomotor and urinary systems. Our results add a new layer of understanding to the critical role of PTPσ in mediating the growth-inhibited state of neurons due to CSPGs within the injured adult spinal cord.

title: Arylsulfatase B Improves Locomotor Function after Mouse Spinal Cord Injury

text: Bacterial chondroitinase ABC (ChaseABC) has been used to remove the inhibitory chondroitin sulfate chains from chondroitin sulfate proteoglycans to improve regeneration after rodent spinal cord injury. We hypothesized that the mammalian enzyme arylsulfatase B (ARSB) would also enhance recovery after mouse spinal cord injury. Application of the mammalian enzyme would be an attractive alternative to ChaseABC because of its more robust chemical stability and reduced immunogenicity. A one-time injection of human ARSB into injured mouse spinal cord eliminated immunoreactivity for chondroitin sulfates within five days, and up to 9 weeks after injury. After a moderate spinal cord injury, we observed improvements of locomotor recovery assessed by the Basso Mouse Scale (BMS) in ARSB treated mice, compared to the buffer-treated control group, at 6 weeks after injection. After a severe spinal cord injury, mice injected with equivalent units of ARSB or ChaseABC improved similarly and both groups achieved significantly more locomotor recovery than the buffer-treated control mice. Serotonin and tyrosine hydroxylase immunoreactive axons were more extensively present in mouse spinal cords treated with ARSB and ChaseABC, and the immunoreactive axons penetrated further beyond the injury site in ARSB or ChaseABC treated mice than in control mice. These results indicate that mammalian ARSB improves functional recovery after CNS injury. The structural/molecular mechanisms underlying the observed functional improvement remain to be elucidated.

title: Self-assembling peptides optimize the post-traumatic milieu and synergistically enhance the effects of neural stem cell therapy after cervical spinal cord injury.

text:
INTRODUCTION The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that optimizing the post-traumatic environment with QL6 self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would improve cell survival, differentiation and functional recovery.
 METHODS A total of 90 Wistar rats received a clip-compression SCI at C7. Within each of two study arms, animals were randomized into 5 groups (NPC, SAP, NPC+SAP, vehicle, and sham). SAPs and NPCs were injected into the spinal cord 1day and 14days post-injury, respectively. Animals received growth factors over 7days and were immunosuppressed. Rats were sacrificed at 4weeks and sections of the cervical spinal cord prepared for immunohistochemistry (first study arm). Neurological function was assessed weekly for 8weeks using a battery of behavioral tests. Nine weeks post-SCI, the corticospinal tract was assessed using fiber-tracking (second arm).
 RESULTS SAP-treated animals had significantly more surviving NPCs which showed increased differentiation to neurons and oligodendrocytes compared to controls. SAPs alone or in combination with NPCs resulted in smaller intramedullary cysts and larger volume of preserved tissue compared to other groups. The combined treatment group showed reduced astrogliosis and chondroitin sulfate proteoglycan deposition. Synaptic connectivity was increased in the NPC and combined treatment groups. Corticospinal tract preservation and behavioral outcomes improved with combinatorial treatment.
 CONCLUSION Injecting SAPs after SCI enhances subsequent NPC survival, integration and differentiation and improves functional recovery.    STATEMENT OF SIGNIFICANCE The hostile environment after spinal cord injury (SCI) can compromise effects of regenerative therapies. We hypothesized that improving this environment with self-assembling peptides (SAPs) before neural precursor cell (NPC) transplantation would support their beneficial effects. SAPs assemble once injected, providing a supportive scaffold for repair and regeneration. We investigated this in a rat model of spinal cord injury. More NPCs survived in SAP-treated animals and these showed increased differentiation compared to controls. SAPS alone or in combination with NPCs resulted in smaller cysts and larger volume of preserved tissue with the combined treatment also reducing scarring and improving behavioral outcomes. Overall, injection of SAPs was shown to improve the efficacy of NPC treatment, a promising finding for those with SCIs.

title: Review of the secondary injury theory of acute spinal cord trauma with emphasis on vascular mechanisms.

text: In patients with spinal cord injury, the primary or mechanical trauma seldom causes total transection, even though the functional loss may be complete. In addition, biochemical and pathological changes in the cord may worsen after injury. To explain these phenomena, the concept of the secondary injury has evolved for which numerous pathophysiological mechanisms have been postulated. This paper reviews the concept of secondary injury with special emphasis on vascular mechanisms. Evidence is presented to support the theory of secondary injury and the hypothesis that a key mechanism is posttraumatic ischemia with resultant infarction of the spinal cord. Evidence for the role of vascular mechanisms has been obtained from a variety of models of acute spinal cord injury in several species. Many different angiographic methods have been used for assessing microcirculation of the cord and for measuring spinal cord blood flow after trauma. With these techniques, the major systemic and local vascular effects of acute spinal cord injury have been identified and implicated in the etiology of secondary injury. The systemic effects of acute spinal cord injury include hypotension and reduced cardiac output. The local effects include loss of autoregulation in the injured segment of the spinal cord and a marked reduction of the microcirculation in both gray and white matter, especially in hemorrhagic regions and in adjacent zones. The microcirculatory loss extends for a considerable distance proximal and distal to the site of injury. Many studies have shown a dose-dependent reduction of spinal cord blood flow varying with the severity of injury, and a reduction of spinal cord blood flow which worsens with time after injury. The functional deficits due to acute spinal cord injury have been measured electrophysiologically with techniques such as motor and somatosensory evoked potentials and have been found proportional to the degree of posttraumatic ischemia. The histological effects include early hemorrhagic necrosis leading to major infarction at the injury site. These posttraumatic vascular effects can be treated. Systemic normotension can be restored with volume expansion or vasopressors, and spinal cord blood flow can be improved with dopamine, steroids, nimodipine, or volume expansion. The combination of nimodipine and volume expansion improves posttraumatic spinal cord blood flow and spinal cord function measured by evoked potentials. These results provide strong evidence that posttraumatic ischemia is an important secondary mechanism of injury, and that it can be counteracted.

title: CNS repair requires both effector and regulatory T cells with distinct temporal and spatial profiles.

text: Monocyte-derived macrophages (mo-MΦs) and T cells have been shown to contribute to spinal cord repair. Recently, the remote brain choroid plexus epithelium (CP) was identified as a portal for monocyte recruitment, and its activation for leukocyte trafficking was found to be IFN-γ-dependent. Here, we addressed how the need for effector T cells can be reconciled with the role of inflammation-resolving immune cells in the repair process. Using an acute spinal cord injury model, we show that in mice deficient in IFN-γ-producing T cells, the CP was not activated, and recruitment of inflammation-resolving mo-MΦ to the spinal cord parenchyma was limited. We further demonstrate that mo-MΦ locally regulated recruitment of thymic-derived Foxp3(+) regulatory T (Treg) cells to the injured spinal cord parenchyma at the subacute/chronic phase. Importantly, an ablation protocol that resulted in reduced Tregs at this stage interfered with tissue remodeling, in contrast to Treg transient ablation, restricted to the 4 d period before the injury, which favored repair. The enhanced functional recovery observed following such a controlled decrease of Tregs suggests that reduced systemic immunosuppression at the time of the insult can enhance CNS repair. Overall, our data highlight a dynamic immune cell network needed for repair, acting in discrete compartments and stages, and involving effector and regulatory T cells, interconnected by mo-MΦ. Any of these populations may be detrimental to the repair process if their level or activity become dysregulated. Accordingly, therapeutic interventions must be both temporally and spatially controlled.

title: De novo expression of Trpm4 initiates secondary hemorrhage in spinal cord injury

text: The role of transient receptor potential M4 (Trpm4), an unusual member of the Trp family of ion channels, is poorly understood. Using rodent models of spinal cord injury, we studied involvement of Trpm4 in the progressive expansion of secondary hemorrhage associated with capillary fragmentation, the most destructive mechanism of secondary injury in the central nervous system. Trpm4 mRNA and protein were abundantly upregulated in capillaries preceding their fragmentation and formation of petechial hemorrhages. Trpm4 expression in vitro rendered COS-7 cells highly susceptible to oncotic swelling and oncotic death following ATP depletion. After spinal cord injury, in vivo gene suppression in rats treated with Trpm4 antisense or in Trpm4−/− mice preserved capillary structural integrity, eliminated secondary hemorrhage, yielded a threefold to fivefold reduction in lesion volume and produced a substantial improvement in neurological function. To our knowledge, this is the first example of a Trp channel that must undergo de novo expression for manifestation of central nervous system pathology.

title: Neuroinflammation in spinal cord injury: therapeutic targets for neuroprotection and regeneration.

text: Traumatic spinal cord injury triggers a complex local inflammatory reaction capable of enhancing repair and exacerbating pathology. The composition and effector potential of the post-injury cellular and molecular immune cascade changes as a function of time and distance from the lesion. Production along this time-space continuum of cytokines, proteases, and growth factors establishes dynamic environments that lead to the death, damage, repair or growth of affected neurons and glia. Microenvironmental cues, therefore, generated by the cells therein, may determine these distinct fates of repair versus pathology. To harness repair, it is necessary to manipulate the assembly and phenotype of cells that comprise the neuroinflammatory response to injury. Here, the potential of the neuroinflammatory response to cause outcomes such as pain, regeneration, and functional recovery is reviewed.

title: Inflammation and its role in neuroprotection, axonal regeneration and functional recovery after spinal cord injury.

text: Trauma to the central nervous system (CNS) triggers intraparenchymal inflammation and activation of systemic immunity with the capacity to exacerbate neuropathology and stimulate mechanisms of tissue repair. Despite our incomplete understanding of the mechanisms that control these divergent functions, immune-based therapies are becoming a therapeutic focus. This review will address the complexities and controversies of post-traumatic neuroinflammation, particularly in spinal cord. In addition, current therapies designed to target neuroinflammatory cascades will be discussed.

title: Microtubule stabilization reduces scarring and causes axon regeneration after spinal cord injury.

text: Hypertrophic scarring and poor intrinsic axon growth capacity constitute major obstacles for spinal cord repair. These processes are tightly regulated by microtubule dynamics. Here, moderate microtubule stabilization decreased scar formation after spinal cord injury in rodents through various cellular mechanisms, including dampening of transforming growth factor-β signaling. It prevented accumulation of chondroitin sulfate proteoglycans and rendered the lesion site permissive for axon regeneration of growth-competent sensory neurons. Microtubule stabilization also promoted growth of central nervous system axons of the Raphe-spinal tract and led to functional improvement. Thus, microtubule stabilization reduces fibrotic scarring and enhances the capacity of axons to grow.

title: Presynaptically Localized Cyclic GMP-Dependent Protein Kinase 1 Is a Key Determinant of Spinal Synaptic Potentiation and Pain Hypersensitivity

text: Synaptic long-term potentiation (LTP) at spinal neurons directly communicating pain-specific inputs from the periphery to the brain has been proposed to serve as a trigger for pain hypersensitivity in pathological states. Previous studies have functionally implicated the NMDA receptor-NO pathway and the downstream second messenger, cGMP, in these processes. Because cGMP can broadly influence diverse ion-channels, kinases, and phosphodiesterases, pre- as well as post-synaptically, the precise identity of cGMP targets mediating spinal LTP, their mechanisms of action, and their locus in the spinal circuitry are still unclear. Here, we found that Protein Kinase G1 (PKG-I) localized presynaptically in nociceptor terminals plays an essential role in the expression of spinal LTP. Using the Cre-lox P system, we generated nociceptor-specific knockout mice lacking PKG-I specifically in presynaptic terminals of nociceptors in the spinal cord, but not in post-synaptic neurons or elsewhere (SNS-PKG-I(-/-) mice). Patch clamp recordings showed that activity-induced LTP at identified synapses between nociceptors and spinal neurons projecting to the periaqueductal grey (PAG) was completely abolished in SNS-PKG-I(-/-) mice, although basal synaptic transmission was not affected. Analyses of synaptic failure rates and paired-pulse ratios indicated a role for presynaptic PKG-I in regulating the probability of neurotransmitter release. Inositol 1,4,5-triphosphate receptor 1 and myosin light chain kinase were recruited as key phosphorylation targets of presynaptic PKG-I in nociceptive neurons. Finally, behavioural analyses in vivo showed marked defects in SNS-PKG-I(-/-) mice in several models of activity-induced nociceptive hypersensitivity, and pharmacological studies identified a clear contribution of PKG-I expressed in spinal terminals of nociceptors. Our results thus indicate that presynaptic mechanisms involving an increase in release probability from nociceptors are operational in the expression of synaptic LTP on spinal-PAG projection neurons and that PKG-I localized in presynaptic nociceptor terminals plays an essential role in this process to regulate pain sensitivity.

title: Another Barrier to Regeneration in the CNS: Activated Macrophages Induce Extensive Retraction of Dystrophic Axons through Direct Physical Interactions

text: Injured axons of the adult CNS undergo lengthy retraction from the initial site of axotomy after spinal cord injury. Macrophage infiltration correlates spatiotemporally with this deleterious phenomenon, but the direct involvement of these inflammatory cells has not been demonstrated. In the present study, we examined the role of macrophages in axonal retraction within the dorsal columns after spinal cord injury in vivo and found that retraction occurred between days 2 and 28 after lesion and that the ends of injured axons were associated with ED-1+ cells. Clodronate liposome-mediated depletion of infiltrating macrophages resulted in a significant reduction in axonal retraction; however, we saw no evidence of regeneration. We used time-lapse imaging of adult dorsal root ganglion neurons in an in vitro model of the glial scar to examine macrophage-axon interactions and observed that adhesive contacts and considerable physical interplay between macrophages and dystrophic axons led to extensive axonal retraction. The induction of retraction was dependent on both the growth state of the axon and the activation state of the macrophage. Only dystrophic adult axons were susceptible to macrophage "attack. " Unlike intrinsically active cell line macrophages, both primary macrophages and microglia required activation to induce axonal retraction. Contact with astrocytes had no deleterious effect on adult dystrophic axons, suggesting that the induction of extensive retraction was specific to phagocytic cells. Our data are the first to indicate a direct role of activated macrophages in axonal retraction by physical cell-cell interactions with injured axons.

title: Proteomic identification of a novel isoform of collapsin response mediator protein-2 in spinal nerves peripheral to dorsal root ganglia.

text: Primary afferent fibers are originated from pseudounipolar sensory cells in dorsal root ganglia (DRG) and transmit external stimuli received in the skin to the spinal cord. Here we undertook a proteomic approach to uncover the polarity of primary afferent fibers. Lumbar spinal nerve segments, peripheral and central to DRG, were dissected from 5-wk-old Wistar rats and the lysates were subjected to large-sized 2-DE at pH 5-6. Among approximately 800 protein spots detected in the central and peripheral fractions, one of the unique spots in the peripheral fraction with MW of 60 kDa and pI of 5.6 was identified as an isoform of collapsin response mediator protein-2 (CRMP-2) by MALDI-TOF MS and Western blots with anti-CRMP-2 antibodies that recognize 1-17 and 486-528 residues. Since this novel spot was detected only in the peripheral fraction, but not in the central fraction, DRG, and other regions of the brain, it was named periCRMP-2. The C-terminal fragment of CRMP-2 was not detected in periCRMP-2 by MS analyses. Expression of periCRMP-2 decreased following sciatic nerve injury. These results suggest that periCRMP-2 is a C-terminal truncated isoform polarized in the peripheral side of spinal nerves and may be involved in nerve degeneration and regeneration.

title: Asymptomatic spinal cord lesions predict disease progression in radiologically isolated syndrome.

text:
BACKGROUND Technological advancements in neuroimaging and the increased use of these diagnostic modalities are responsible for the discovery of incidentally identified anomalies within the CNS. In addition to the identification of unanticipated brain MRI abnormalities suggestive of demyelinating disease in patients undergoing neuroimaging for a medical reason other than evaluation for multiple sclerosis (MS), asymptomatic spinal cord lesions are periodically identified.
 OBJECTIVE To determine if asymptomatic spinal cord lesions are associated with clinical progression in subjects with radiologically isolated syndrome (RIS).
 METHODS A retrospective review of RIS cases at the University of California, San Francisco Multiple Sclerosis Center was performed. The presence of asymptomatic cervical spinal cord MRI lesions was analyzed as a potential predictor for clinical progression.
 RESULTS Twenty-five of 71 subjects with RIS possessed findings within the cervical spine that were highly suggestive of demyelinating disease. Of these subjects, 21 (84%) progressed clinically to clinically isolated syndrome (n = 19) or primary progressive multiple sclerosis (n = 2) over a median time of 1.6 years from the date of RIS identification (interquartile range 0.8-3.8). The sensitivity, specificity, and positive predictive value of an asymptomatic spinal cord lesion for subsequent development of either a first demyelinating attack or primary progressive MS were 87.5%, 91.5%, and 84%, respectively. The odds ratio of clinical progression was 75.3 (95% confidence interval 16.1-350.0, p < 0.0001). This association remained significant after adjusting for potential confounders.
 CONCLUSION These findings suggest that the presence of asymptomatic spinal cord lesions place subjects with RIS at substantial risk for clinical conversion to either an acute or progressive event, a risk that is independent of brain lesions on MRI.

title: Involvement of S-nitrosylation of actin in inhibition of neurotransmitter release by nitric oxide

text:
BACKGROUND The role of the diffusible messenger nitric oxide (NO) in the regulation of pain transmission is still a debate of matter, pro-nociceptive and/or anti-nociceptive. S-Nitrosylation, the reversible post-translational modification of selective cysteine residues in proteins, has emerged as an important mechanism by which NO acts as a signaling molecule. The occurrence of S-nitrosylation in the spinal cord and its targets that may modulate pain transmission remain unclarified. The "biotin-switch" method and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were employed for identifying S-nitrosylated proteins.
 RESULTS Here we show that actin was a major protein S-nitrosylated in the spinal cord by the NO donor, S-nitroso-N-acetyl-DL-penicillamine (SNAP). Interestingly, actin was S-nitrosylated, more in the S2 fraction than in the P2 fraction of the spinal homogenate. Treatment of PC12 cells with SNAP caused rapid S-nitrosylation of actin and inhibited dopamine release from the cells. Just like cytochalasin B, which depolymerizes actin, SNAP decreased the amount of filamentous actin cytoskeleton just beneath the membrane. The inhibition of dopamine release was not attenuated by inhibitors of soluble guanylyl cyclase and cGMP-dependent protein kinase.
 CONCLUSION The present study demonstrates that actin is a major S-nitrosylated protein in the spinal cord and suggests that NO directly regulates neurotransmitter release by S-nitrosylation in addition to the well-known phosphorylation by cGMP-dependent protein kinase.

title: Eosinophil pathogenicity mechanisms and therapeutics in neuromyelitis optica.

text: Eosinophils are abundant in inflammatory demyelinating lesions in neuromyelitis optica (NMO). We used cell culture, ex vivo spinal cord slices, and in vivo mouse models of NMO to investigate the role of eosinophils in NMO pathogenesis and the therapeutic potential of eosinophil inhibitors. Eosinophils cultured from mouse bone marrow produced antibody-dependent cell-mediated cytotoxicity (ADCC) in cell cultures expressing aquaporin-4 in the presence of NMO autoantibody (NMO-IgG). In the presence of complement, eosinophils greatly increased cell killing by a complement-dependent cell-mediated cytotoxicity (CDCC) mechanism. NMO pathology was produced in NMO-IgG-treated spinal cord slice cultures by inclusion of eosinophils or their granule toxins. The second-generation antihistamines cetirizine and ketotifen, which have eosinophil-stabilizing actions, greatly reduced NMO-IgG/eosinophil-dependent cytotoxicity and NMO pathology. In live mice, demyelinating NMO lesions produced by continuous intracerebral injection of NMO-IgG and complement showed marked eosinophil infiltration. Lesion severity was increased in transgenic hypereosinophilic mice. Lesion severity was reduced in mice made hypoeosinophilic by anti-IL-5 antibody or by gene deletion, and in normal mice receiving cetirizine orally. Our results implicate the involvement of eosinophils in NMO pathogenesis by ADCC and CDCC mechanisms and suggest the therapeutic utility of approved eosinophil-stabilizing drugs.

title: Rapamycin treatment augments motor neuron degeneration in SOD1(G93A) mouse model of amyotrophic lateral sclerosis.

text: Aberrant protein misfolding may contribute to the pathogenesis of amyotrophic lateral sclerosis (ALS) but the detailed mechanisms are largely unknown. Our previous study has shown that autophagy is altered in the mouse model of ALS. In the present study, we systematically investigated the correlation of the autophagic alteration with the motor neurons (MNs) degeneration in the ALS mice. We have demonstrated that the autophagic protein marker LC3-II is markedly and specifically increased in the spinal cord MNs of the ALS mice. Electron microscopy and immunochemistry studies have shown that autophagic vacuoles are significantly accumulated in the dystrophic axons of spinal cord MNs of the ALS mice. All these changes in the ALS mice appear at the age of 90 d when the ALS mice display modest clinical symptoms; and they become prominent at the age of 120 d. The clinical symptoms are correlated with the progression of MNs degeneration. Moreover, we have found that p62/SQSTM1 is accumulated progressively in the spinal cord, indicating that the possibility of impaired autophagic flux in the SOD1(G93A) mice. Furthermore, to our surprise, we have found that treatment with autophagy enhancer rapamycin accelerates the MNs degeneration, shortens the life span of the ALS mice, and has no obvious effects on the accumulation of SOD1 aggregates. In addition, we have demonstrated that rapamycin treatment in the ALS mice causes more severe mitochondrial impairment, higher Bax levels and greater caspase-3 activation. These findings suggest that selective degeneration of MNs is associated with the impairment of the autophagy pathway and that rapamycin treatment may exacerbate the pathological processing through apoptosis and other mechanisms in the ALS mice.

title: Systematic review of role of bisphosphonates on skeletal morbidity in metastatic cancer.

text:
OBJECTIVE To review the evidence for the use of bisphosphonates to reduce skeletal morbidity in cancer patients with bone metastases.
 DATA SOURCES Electronic databases, scanning reference lists, and consultation with experts and pharmaceutical companies. Foreign language papers were included.    STUDY SELECTION Included trials were randomised controlled trials of patients with malignant disease and bone metastases who were treated with oral or intravenous bisphosphonate compared with another bisphosphonate, placebo, or standard care. All trials measured at least one outcome of skeletal morbidity.
 RESULTS 95 articles were identified; 30 studies fulfilled inclusion criteria. In studies that lasted > or = 6 months, compared with placebo bisphosphonates significantly reduced the odds ratio for fractures (vertebral 0.69, 95% confidence interval 0.57 to 0.84, P < 0.0001; non-vertebral 0.65, 0.54 to 0.79, P < 0.0001; combined 0.65, 0.55 to 0.78, P < 0.0001), radiotherapy (0.67, 0.57 to 0.79, P < 0.0001), and hypercalcaemia (0.54, 0.36 to 0.81, P = 0.003) but not for orthopaedic surgery (0.70, 0.46 to 1.05, P = 0.086) or spinal cord compression (0.71, 0.47 to 1.08, P = 0.113). The reduction in orthopaedic surgery was significant in studies that lasted over a year (0.59, 0.39 to 0.88, P = 0.009). Use of bisphosphonates significantly increased time to first skeletal related event but did not increase survival. Subanalyses showed that most evidence supports use of intravenous aminobisphosphonates.
 CONCLUSIONS In people with metastatic bone disease bisphosphonates significantly decrease skeletal morbidity, except for spinal cord compression and increased time to first skeletal related event. Treatment should start when bone metastases are diagnosed and continue until it is no longer clinically relevant.

title: Potentiation of NMDA currents by pituitary adenylate cyclase activating polypeptide in neonatal rat sympathetic preganglionic neurons.

text: Whole cell patch-clamp recordings were made from sympathetic preganglionic neurons (SPNs) in the intermediolateral cell column of thoracolumbar spinal cord slices of 12- to 16-day-old rats, and the effects of pituitary adenylate cyclase activating polypeptide (PACAP)-38 on N-methyl-D-aspartate (NMDA)- and kainate (KA)-induced inward currents were examined. PACAP, in concentrations (10-30 nM) that caused no significant change of holding currents, reversibly increased NMDA-induced currents but not KA-induced currents. At higher concentrations (>30 nM), the peptide produced a sustained inward current. The potentiating effect of PACAP was nullified by prior incubation of the slices with the adenylate cyclase inhibitor MDL-12,330A (25 microM). Further, superfusing the slices with the membrane-permeable cyclic AMP analogue N6,2'-O-dibutyryladenosine 3':5'-cyclic monophosphate (100-300 microM) in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (700 microM) increased the NMDA currents. This result suggests that PACAP selectively increases NMDA-receptor-mediated responses in the rat SPNs, probably via a cyclic-AMP-dependent mechanism, providing evidence that the peptide may be involved in synaptic plasticity.

title: Expression of the gene encoding the chemorepellent semaphorin III is induced in the fibroblast component of neural scar tissue formed following injuries of adult but not neonatal CNS.

text: This study evaluates the expression of the chemorepellent semaphorin III (D)/collapsin-1 (sema III) following lesions to the rat CNS. Scar tissue, formed after penetrating injuries to the lateral olfactory tract (LOT), cortex, perforant pathway, and spinal cord, contained numerous spindle-shaped cells expressing high levels of sema III mRNA. The properties of these cells were investigated in detail in the lesioned LOT. Most sema III mRNA-positive cells were located in the core of the scar and expressed proteins characteristic for fibroblast-like cells. Neuropilin-1, a sema III receptor, was expressed in injured neurons with projections to the lesion site, in a subpopulation of scar-associated cells and in blood vessels around the scar. In contrast to lesions made in the mature CNS, LOT transection in neonates did not induce sema III mRNA expression within cells in the lesion and was followed by vigorous axonal regeneration. The concomitant expression of sema III and its receptor neuropilin-1 in the scar suggests that sema III/neuropilin-1-mediated mechanisms are involved in CNS scar formation. The expression of the secreted chemorepellent sema III following CNS injury provides the first evidence that chemorepulsive semaphorins may contribute to the inhibitory effects exerted by scars on the outgrowth of injured CNS neurites. The vigorous regrowth of injured axons in the absence of sema III following early neonatal lesions is consistent with this notion. The inactivation of sema III in scar tissue by either antibody perturbation or by genetic or pharmacological intervention could be a powerful means to promote long-distance regeneration in the adult CNS.