Miracle-dz/UniFAR-FTUs huggingface dataset:
Temporal and functional dynamics of the transcriptome during nerve growth factor‐induced differentiation

The rat pheochromocytoma cell line (PC12) is an extensively used model to study neuronal differentiation. The initial signaling cascades triggered by nerve growth factor (NGF) stimulation have been subject to thorough investigation and are well characterized. However, knowledge of temporal transcriptomal regulation during NGF‐induced differentiation of PC12 cells remains far from complete. We performed a microarray study that characterized temporal and functional changes of the transcriptome during 4 subsequent days of differentiation of Neuroscreen‐1 PC12 cells. By analyzing the transcription profiles of 1595 NGF‐regulated genes, we show a large diversity of transcriptional regulation in time. Also, we quantitatively identified 26 out of 243 predefined biological process and 30 out of 255 predefined molecular function classes that are specifically regulated by NGF. Combining the temporal and functional transcriptomal data revealed that NGF selectively exerts a temporally coordinated regulation of genes implicated in protein biosynthesis, intracellular signaling, cell structure, chromatin packaging and remodeling, intracellular protein traffic, mRNA transcription, and cell cycle. We will discuss how NGF‐induced changes may modulate the transcriptional response to NGF itself during differentiation.
Genetic inactivation of p62 leads to accumulation of hyperphosphorylated tau and neurodegeneration

The signaling adapter p62 plays a coordinating role in mediating phosphorylation and ubiquitin‐dependent trafficking of interacting proteins. However, there is little known about the physiologic role of this protein in brain. Here, we report age‐dependent constitutive activation of glycogen synthase kinase 3β, protein kinase B, mitogen‐activated protein kinase, and c‐Jun‐N‐terminal kinase in adult p62−/− mice resulting in hyperphosphorylated tau, neurofibrillary tangles, and neurodegeneration. Biochemical fractionation of p62−/− brain led to recovery of aggregated K63‐ubiquitinated tau. Loss of p62 was manifested by increased anxiety, depression, loss of working memory, and reduced serum brain‐derived neurotrophic factor levels. Our findings reveal a novel role for p62 as a chaperone that regulates tau solubility thereby preventing tau aggregation. This study provides a clear demonstration of an Alzheimer‐like phenotype in a mouse model in the absence of expression of human genes carrying mutations in amyloid‐beta protein precursor, presenilin, or tau. Thus, these findings provide new insight into manifestation of sporadic Alzheimer disease and the impact of obesity.
Amyloid beta peptide and NMDA induce ROS from NADPH oxidase and AA release from cytosolic phospholipase A2 in cortical neurons

Increase in oxidative stress has been postulated to play an important role in the pathogenesis of a number of neurodegenerative diseases including Alzheimer’s disease. There is evidence for involvement of amyloid‐β peptide (Aβ) in mediating the oxidative damage to neurons. Despite yet unknown mechanism, Aβ appears to exert action on the ionotropic glutamate receptors, especially the N‐methyl‐D‐aspartic acid (NMDA) receptor subtypes. In this study, we showed that NMDA and oligomeric Aβ1–42 could induce reactive oxygen species (ROS) production from cortical neurons through activation of NADPH oxidase. ROS derived from NADPH oxidase led to activation of extracellular signal‐regulated kinase 1/2, phosphorylation of cytosolic phospholipase A2α (cPLA2α), and arachidonic acid (AA) release. In addition, Aβ1–42‐induced AA release was inhibited by d(−)‐2‐amino‐5‐phosphonopentanoic acid and memantine, two different NMDA receptor antagonists, suggesting action of Aβ through the NMDA receptor. Besides serving as a precursor for eicosanoids, AA is also regarded as a retrograde messenger and plays a role in modulating synaptic plasticity. Other phospholipase A2 products such as lysophospholipids can perturb membrane phospholipids. These results suggest an oxidative‐degradative mechanism for oligomeric Aβ1–42 to induce ROS production and stimulate AA release through the NMDA receptors. This novel mechanism may contribute to the oxidative stress hypothesis and synaptic failure that underline the pathogenesis of Alzheimer’s disease.
Histamine induces neural stem cell proliferation and neuronal differentiation by activation of distinct histamine receptors

Histamine has neurotransmitter/neuromodulator functions in the adult brain, but its role during CNS development has been elusive. We studied histamine effects on proliferation, cell death and differentiation of neuroepithelial stem cells from rat cerebral cortex in vitro. RT‐PCR and Western blot experiments showed that proliferating and differentiated cells express histamine H1, H2 and H3 receptors. Treatments with histamine concentrations (100 nM–1 mM) caused significant increases in cell numbers without affecting Nestin expression. Cell proliferation was evaluated by BrdU incorporation; histamine caused a significant increase dependent on H2 receptor activation. Apoptotic cell death during proliferation was significantly decreased at all histamine concentrations, and cell death was promoted in a concentration‐dependent manner by histamine in differentiated cells. Immunocytochemistry studies showed that histamine increased 3‐fold the number of neurons after differentiation, mainly by activation of H1 receptor, and also significantly decreased the glial (astrocytic) cell proportion, when compared to control conditions. In summary, histamine increases cell number during proliferative conditions, and has a neuronal‐differentiating action on neural stem cells, suggesting that the elevated histamine concentration reported during development might play a role in cerebrocortical neurogenesis, by activation of H2 receptors to promote proliferation of neural precursors, and favoring neuronal fate by H1‐mediated stimulation.
Depletion of 14‐3‐3 zeta elicits endoplasmic reticulum stress and cell death, and increases vulnerability to kainate‐induced injury in mouse hippocampal cultures

14‐3‐3 proteins are ubiquitous signalling molecules that regulate development and survival pathways in brain. Altered expression and cellular localization of 14‐3‐3 proteins has been implicated in neurodegenerative diseases and in neuronal death after acute neurological insults, including seizures. Presently, we examined expression and function of 14‐3‐3 isoforms in vitro using mouse organotypic hippocampal cultures. Treatment of cultures with the endoplasmic reticulum (ER) stressor tunicamycin caused an increase in levels of 14‐3‐3 zeta within the ER‐containing microsomal fraction, along with up‐regulation of Lys‐Asp‐Glu‐Leu‐containing proteins and calnexin, and the selective death of dentate granule cells. Depletion of 14‐3‐3 zeta levels using small interfering RNA induced both ER stress proteins and death of granule cells. Treatment of hippocampal cultures with the excitotoxin kainic acid increased levels of Lys‐Asp‐Glu‐Leu‐containing proteins and microsomal 14‐3‐3 zeta levels and caused cell death within the CA1, CA3 and dentate gyrus of the hippocampus. Kainic acid‐induced damage was significantly increased in each hippocampal subfield of cultures treated with small interfering RNA targeting 14‐3‐3 zeta. The present data indicate a role for 14‐3‐3 zeta in survival responses following ER stress and possibly protection against seizure injury to the hippocampus.
Forskolin induction of late‐LTP and up‐regulation of 5′ TOP mRNAs translation via mTOR, ERK, and PI3K in hippocampal pyramidal cells

The late phase of long‐term potentiation (LTP) requires activation of the mammalian target of rapamycin (mTOR) pathway and synthesis of new proteins. mTOR regulates protein synthesis via phosphorylation of 4E‐binding proteins (4E‐BPs) and S6K, and via selective up‐regulation of 5′ terminal oligopyrimidine (5′ TOP) mRNAs that encode components of the translational machinery. In this study, we explored the regulation of 5′ TOP mRNAs during late‐LTP (L‐LTP). Synaptic plasticity was studied at Schaffer collateral – CA1 pyramidal cell synapses in rat organotypic hippocampal slices. Forskolin, an adenylate cyclase activator, induced L‐LTP in organotypic slices that was mTOR‐dependent. To determine if 5′ TOP mRNAs are specifically up‐regulated during L‐LTP, we generated a 5′ TOP‐myr‐dYFP reporter to selectively monitor 5′ TOP translation. Confocal imaging experiments in cultured slices revealed an increase in somatic and dendritic fluorescence after forskolin treatment. This up‐regulation was dependent on an intact TOP sequence and was mTOR, extracellular signal‐regulated kinase (ERK), and phosphatidylinositol 3‐kinase (PI3K)‐dependent. Our findings indicate that forskolin induces L‐LTP in hippocampal neurons and up‐regulates 5′ TOP mRNAs translation via mTOR, suggesting that up‐regulation of the translational machinery is a candidate mechanism for the stabilization of LTP.
Antigen–antibody dissociation in Alzheimer disease: a novel approach to diagnosis

With the ever‐increasing population of aged individuals at risk of developing Alzheimer’s disease (AD), there is an urgent need for a sensitive, specific, non‐invasive, and diagnostic standard. The majority of efforts have focused on auto‐antibodies against amyloid‐β (Aβ) protein, both as a potential treatment, and a reliable biomarker of AD pathology. Naturally occurring antibodies against Aβ are found in the CSF and plasma of patients with AD as well as healthy control subjects. To date, differences between diseased and control subjects have been highly variable. However, some of the antibody will be in preformed antigen–antibody complexes and the extent and nature of such complexes may provide a potential explanation for the variable results reported in human studies. Thus, measuring total amounts of antigen or antibody following unmasking is critical. Here, using a technique for dissociating antibody–antigen complexes, we found significant differences in serum antibodies to Aβ between AD and aged‐matched control subjects. While the current study demonstrates the relevance of measuring total antibody, bound and unbound, against Aβ in AD, this technique may be applicable to diseases such as acquired immune deficiency syndrome and hepatitis B where determination of antigen and antibody levels are important for disease diagnosis and assessing disease progression.
Involvement of the low‐density lipoprotein receptor‐related protein in the transcytosis of the brain delivery vector Angiopep‐2

The blood–brain barrier (BBB) restricts the entry of proteins as well as potential drugs to cerebral tissues. We previously reported that a family of Kunitz domain‐derived peptides called Angiopeps can be used as a drug delivery system for the brain. Here, we further characterize the transcytosis ability of these peptides using an in vitro model of the BBB and in situ brain perfusion. These peptides, and in particular Angiopep‐2, exhibited higher transcytosis capacity and parenchymal accumulation than do transferrin, lactoferrin, and avidin. Angiopep‐2 transport and accumulation in brain endothelial cells were unaffected by the P‐glycoprotein inhibitor, cyclosporin A, indicating that this peptide is not a substrate for the efflux pump P‐glycoprotein. However, competition studies show that activated α2‐macroglobulin, a specific ligand for the low‐density lipoprotein receptor‐related protein‐1 (LRP1) and Angiopep‐2 can share the same receptor. In addition, LRP1 was detected in glioblastomas and brain metastases from lung and skin cancers. Fluorescent microscopy also revealed that Alexa488‐Angiopep‐2 co‐localized with LRP1 in brain endothelial cell monolayers. Overall, these results suggest that Angiopep‐2 transport across the BBB is, in part, mediated by LRP1.
Clusterin increases post‐ischemic damages in organotypic hippocampal slice cultures

Clusterin or apolipoprotein J is a heterodimeric glycoprotein which is known to be increased during tissue involution in response to hormonal changes or injury and under circumstances leading to apoptosis. Previous studies in wild‐type (WT) and clusterin‐null (Clu−/−) mice indicated a protective role of clusterin over‐expression in astrocytes lasting up to 90 days post‐ischemia. However, in in vitro and in vivo models of neonatal hypoxia‐ischemia, clusterin exacerbates necrotic cell death. We developed recombinant forms of clusterin and examined their effect on propidium iodide uptake, neuronal and synaptic markers as well as electrophysiological recordings in hippocampal slice cultures from Clu−/− and WT mice subjected to oxygen‐glucose deprivation (OGD). WT mice displayed a marked up‐regulation of clusterin associated with electrophysiological deficits and dramatic increase of propidium iodide uptake 5 days post‐OGD. Immunocytochemical and western blot analyses revealed a substantial decrease of neuronal nuclei and synaptophysin immunoreactivity that predominated in WT mice. These findings contrasted with the relative post‐OGD resistance of Clu−/− mice. The addition of biologically active recombinant forms of human clusterin for 24 h post‐OGD led to the abolishment of the ischemic tolerance in Clu−/− slices. This deleterious effect of clusterin was reverted by the concomitant administration of the NMDA receptor antagonist, d‐2‐amino‐5‐phosphonopentanoate. The present data indicate that in an in vitro model of ischemia characterized by the predominance of NMDA‐mediated cell death, clusterin exerts a negative effect on the structural integrity and functionality of hippocampal neurons.
Opposing effects of retinoid signaling on astrogliogenesis in embryonic day 13 and 17 cortical progenitor cells

All‐trans retinoic acid (RA) is a differentiation factor in many tissues. However, its role in astrogliogenesis has not been extensively studied. Here, we investigated the effect of RA on the regulation of astrogliogenesis at different cortical developmental stages. We prepared rat cortical progenitor cells from embryonic day (E) 13 and E17, which correspond to the beginning of neurogenic and astrogliogenic periods, respectively. Surprisingly, RA promoted astrogliogenesis at E17 but inhibited astrogliogenesis induced by ciliary neurotrophic factor (CNTF) at E13. The inhibitory effect of RA on astrogliogenesis at E13 was not due to premature commitment of progenitors to a neuronal or oligodendroglial lineage. Rather, RA retained more progenitors in a proliferative state. Furthermore, RA inhibition of astrogliogenesis at E13 was independent of STAT3 signaling and required the function of the α and β isoforms of the RA receptors (RAR). Moreover, the differential response of E13 and E17 progenitors to RA was due to differences in the intrinsic properties of these cells that are preserved in vitro. The inhibitory effect of RA on cytokine‐induced astrogliogenesis at E13 may contribute to silencing of any potential precocious astrogliogenesis during the neurogenic period.
NFκB in the mechanism of ammonia‐induced astrocyte swelling in culture

Astrocyte swelling and brain edema are major neuropathological findings in the acute form of hepatic encephalopathy (fulminant hepatic failure), and substantial evidence supports the view that elevated brain ammonia level is an important etiological factor in this condition. Although the mechanism by which ammonia brings about astrocyte swelling remains to be determined, oxidative/nitrosative stress and mitogen‐activated protein kinases (MAPKs) have been considered as important elements in this process. One factor known to be activated by both oxidative stress and MAPKs is nuclear factor κB (NFκB), a transcription factor that activates many genes, including inducible nitric oxide synthase (iNOS). As the product of iNOS, nitric oxide (NO), is known to cause astrocyte swelling, we examined the potential involvement of NFκB in ammonia‐induced astrocyte swelling. Western blot analysis of cultured astrocytes showed a significant increase in NFκB nuclear translocation (a measure of NFκB activation) from 12 h to 2 days after treatment with NH4Cl (5 mM). Cultures treated with anti‐oxidants, including superoxide dismutase, catalase, and vitamin E as well as the MAPKs inhibitors, SB239063 (an inhibitor of p38‐MAPK) and SP600125 (an inhibitor of c‐Jun N‐terminal kinase), significantly diminished NFκB activation by ammonia, supporting a role of oxidative stress and MAPKs in NFκB activation. The activation of NFκB was associated with increased iNOS protein expression and NO generation, and these changes were blocked by BAY 11–7082, an inhibitor of NFκB. Additionally, ammonia‐induced astrocyte swelling was inhibited by the NFκB inhibitors, BAY 11–7082 and SN‐50, thereby implicating NFκB in the mechanism of astrocyte swelling. Our studies indicate that cultured astrocytes exposed to ammonia display NFκB activation, which is likely to be a consequence of oxidative stress and activation of MAPKs. NFκB activation appears to contribute to the mechanism of ammonia‐induced astrocyte swelling, apparently through its up‐regulation of iNOS protein expression and the subsequent generation of NO.
Trying to succeed when the right ventricle fails

Purpose of review Compared with the left ventricle, studies of right ventricular failure as a distinct clinical entity have lagged behind. Evolving appreciation of the prognostic significance of right ventricular dysfunction in the heart failure population and advances in noninvasive imaging have provided the impetus for recent investigation into the assessment and management of right ventricular failure. Recent findings Pulmonary hypertension and attendant right ventricular dysfunction are prevalent in patients with systolic and diastolic heart failure and are associated with poor survival. Simple echocardiographic and MRI indices of right ventricular function relate to prognosis and may also be useful in following response to therapy. Management of acute and chronic right ventricular failure is largely empiric and is focused on treating the underlying cause along with judicious use of diuretics and inotropes. The use of left ventricular assist devices to help treat pulmonary hypertension in heart failure is an emerging strategy in transplant-eligible patients. Summary Right ventricular failure is clinically significant and merits further dedicated study. Parameters of right ventricular dysfunction can be assessed noninvasively. An approach to the management of acute and chronic right ventricular failure should take into consideration novel pharmacologic and device-based therapies.
Characterization of urotensin II, distribution of urotensin II, urotensin II‐related peptide and UT receptor mRNAs in mouse: evidence of urotensin II at the neuromuscular junction

Urotensin II (UII) and UII‐related peptide (URP) are paralog neuropeptides whose existence and distribution in mouse have not yet been investigated. In this study, we showed by HPLC/RIA analysis that the UII‐immunoreactive molecule in the mouse brain corresponds to a new UII17 isoform. Moreover, calcium mobilization assays indicated that UII17 and URP were equally potent in stimulating UII receptor (UT receptor). Quantitative RT‐PCR and in situ hybridization analysis revealed that in the CNS UII and URP mRNAs were predominantly expressed in brainstem and spinal motoneurons. Besides, they were differentially expressed in the medial vestibular nucleus, locus coeruleus and the ventral medulla. In periphery, both mRNAs were expressed in skeletal muscle, testis, vagina, stomach, and gall bladder, whereas only URP mRNA could be detected in the seminal vesicle, heart, colon, and thymus. By contrast, the UT receptor mRNA was widely expressed, and notably, very high amounts of transcript occurred in skeletal muscle and prostate. In the biceps femoris muscle, UII‐like immunoreactivity was shown to coexist with synaptophysin in muscle motor end plate regions. Altogether these results suggest that (i) UII and URP may have many redundant biological effects, especially at the neuromuscular junction; (ii) URP may more specifically participate to autonomic, cardiovascular and reproductive functions.
Fibrates in the treatment of cardiovascular risk and atherogenic dyslipidaemia

Purpose New data have emerged over the last few years about the role of fibrates in treatment of microvascular and macrovascular disease. Recent findings Endpoint studies have been conducted with fibrates in coronary heart disease (CHD) since 1971 and initial results were contradictory. Fibrates later showed benefits in patients with low HDL-C and low LDL-C. The prominence ascribed to the lipid triad of the metabolic syndrome and the increasing prevalence of diabetes has increased the topicality of fibrates given their main action of converting small dense to light buoyant LDL. The Fenofibrate Intervention in Endpoint Lowering in Diabetes (FIELD) study has carried on the tradition. Fenofibrate therapy in 9795 patients comprising a mixed low-risk primary and a medium-risk secondary prevention cohort resulted in an 11% reduction in coronary events (P = 0.16), a similar but significant reduction in cardiovascular events (P = 0.04; number-needed-to-treat = 70). The benefits were concentrated in primary prevention and on nonfatal myocardial events, and post-hoc greater effects were seen in patients with moderate hypertriglyceridaemia (>2.3 mmol/l) and low HDL-C, as had previously been noted in a trial with bezafibrate. Safety was generally good, including in combination with statins, but old concerns about sudden death, pancreatitis and venous thrombosis returned. Unexpected benefits were seen with fenofibrate for microvascular endpoints including microalbuminuria and retinopathy. Summary Fenofibrate and bezafibrate are reasonable second-line therapies for dyslipidaemia and in diabetes, and well tolerated in combination therapy. The benefits of fenofibrate for microvascular disease and its potential role in combination therapy require further confirmation.
Differential migration, LPS‐induced cytokine, chemokine, and NO expression in immortalized BV‐2 and HAPI cell lines and primary microglial cultures

Microglial cells are hematopoietically derived monocytes of the CNS and serve important neuromodulatory, neurotrophic, and neuroimmune roles. Following insult to the CNS, microglia develop a reactive phenotype, migrate to the site of injury, proliferate, and release a range of proinflammatory, anti‐inflammatory, and neurotrophic factors. Isolation of primary microglial cell cultures has been an integral step in elucidating the many roles of these cells. In addition to primary microglial cells, several immortalized cell lines have been created to model primary microglia in vitro, including murine‐derived BV‐2 cells and rat derived highly aggressive proliferating immortalized (HAPI) cells. Here, we compare rat primary microglial, BV‐2, and HAPI cells in experiments assessing migration, expression of activation markers, and production and release of nitric oxide, cytokines, and chemokines. BV‐2 and HAPI cells responded similarly to primary microglia in experiments assessing migration, ionized calcium binding adaptor molecule 1 expression, and nitric oxide release. However, BV‐2 and HAPI cells did not model primary microglia in experiments assessing tumor necrosis factor‐α, interleukin‐1β, interleukin‐6, and monocyte chemoattractant protein‐1 expression and release and phospho‐extracellular signal‐regulated kinase 44/42 expression following lipopolysaccharide treatment. These results indicate that BV‐2 and HAPI cell cultures only partially model primary microglia and that their use should therefore be carefully considered.