pinecone/core-2020-05-10-deduplication huggingface dataset:
IGF-1-mediated osteoblastic niche expansion enhances long-term hematopoietic stem cell engraftment after murine bone marrow transplantation

The efficiency of hematopoietic stem cell (HSC) engraft-ment after bone marrow (BM) transplantation depends largely on the capacity of the marrow microenvironment to accept the transplanted cells. While radioablation of BM damages osteoblastic stem cell niches, little is known about their restoration and mechanisms governing their receptivity to engraft transplanted HSCs. We previously reported rapid restoration and profound expansion of the marrow endosteal microenvironment in response to marrow radioablation. Here, we show that this reorganization represents proliferation of mature endosteal osteoblasts which seem to arise from a small subset of high-proliferative, relatively radio-resistant endosteal cells. Multiple layers of osteoblasts form along the endosteal surface within 48 hours after total body irradiation, concomitant with a peak in marrow cytokine expression. This niche reorganization fosters homing of the transplanted hematopoietic cells to the host marrow space and engraft-ment of long-term-HSC. Inhibition of insulin-like growth factor (IGF)-1-receptor tyrosine kinase signaling abrogates endosteal osteoblast proliferation and donor HSC engraft-ment, suggesting that the cytokine IGF-1 is a crucial mediator of endosteal niche reorganization and consequently donor HSC engraftment. Further understanding of this novel mechanism of IGF-1-dependent osteoblastic niche expansion and HSC engraftment may yield clinical applications for improving engraftment efficiency after clinical HSC transplantation. © AlphaMed Press
Two novel splice variants of SOX2OT, SOX2OT-S1, and SOX2OT-S2 are coupregulated with SOX2 and OCT4 in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) have emerged as new regulators of stem cell pluripotency and tumorigenesis. The SOX2 gene, a master regulator of pluripotency, is embedded within the third intron of a lncRNA known as SOX2 overlapping transcript (SOX2OT). SOX2OT has been suspected to participate in regulation of SOX2 expression and/or other related processes; nevertheless, its potential involvement in tumor initiation and/or progression is unclear. Here, we have evaluated a possible correlation between expression patterns of SOX2OT and those of master regulators of pluripotency, SOX2 and OCT4, in esophageal squamous cell carcinoma (ESCC) tissue samples. We have also examined its potential function in the human embryonic carcinoma stem cell line, NTERA2 (NT2), which highly expresses SOX2OT, SOX2, and OCT4. Our data revealed a significant coupregulation of SOX2OT along with SOX2 and OCT4 in tumor samples, compared to the non-tumor tissues obtained from the margin of same tumors. We also identified two novel splice variants of SOX2OT (SOX2OT-S1 and SOX2OT-S2) which coupregulated with SOX2 and OCT4 in ESCCs. Suppressing SOX2OT variants caused a profound alteration in cell cycle distribution, including a 5.9 and 6.9 time increase in sub-G1 phase of cell cycle for SOX2OT-S1 and SOX2OT-S2, respectively. The expression of all variants was significantly diminished, upon the induction of neural differentiation in NT2 cells, suggesting their potential functional links to the undifferentiated state of the cells. Our data suggest a part for SOX2OT spliced variants in tumor initiation and/or progression as well as regulating pluripotent state of stem cells. © AlphaMed Press 2013
Astrocytes reverted to a neural progenitor-like state with transforming growth factor alpha are sensitized to cancerous transformation.

International audienceGliomas, the most frequent primitive central nervous system tumors, have been suggested to originate from astrocytes or from neural progenitors/stem cells. However, the precise identity of the cells at the origin of gliomas remains a matter of debate because no pre-neoplastic state has been yet identified. Transforming growth factor (TGF)-alpha, an epidermal growth factor family member, is frequently overexpressed in the early stages of glioma progression. We previously demonstrated that prolonged exposure of astrocytes to TGF-alpha is sufficient to trigger their reversion to a neural progenitor-like state. To determine whether TGF-alpha dedifferentiating effects are associated with cancerous transforming effects, we grafted intracerebrally dedifferentiated astrocytes. We show that these cells had the same cytogenomic profile as astrocytes, survived in vivo, and did not give birth to tumors. When astrocytes dedifferentiated with TGF-alpha were submitted to oncogenic stress using gamma irradiation, they acquired cancerous properties: they were immortalized, showed cytogenomic abnormalities, and formed high-grade glioma-like tumors after brain grafting. In contrast, irradiation did not modify the lifespan of astrocytes cultivated in serum-free medium. Addition of TGF-alpha after irradiation did not promote their transformation but decreased their lifespan. These results demonstrate that reversion of mature astrocytes to an embryonic state without genomic manipulation is sufficient to sensitize them to oncogenic stress
The Transition from Stem Cell to Progenitor Spermatogonia and Male Fertility Requires the SHP2 Protein Tyrosine Phosphatase

SHP2 is a widely expressed protein tyrosine phosphatase required for signal transduction from multiple cell surface receptors. Gain and loss of function SHP2 mutations in humans are known to cause Noonan and LEOPARD syndromes, respectively, that are characterized by numerous pathological conditions including male infertility. Using conditional gene targeting in the mouse, we found that SHP2 is required for maintaining spermatogonial stem cells (SSCs) and the production of germ cells required for male fertility. After deleting SHP2, spermatogenesis was halted at the initial step during which transit‐amplifying undifferentiated spermatogonia are produced from SSCs. In the absence of SHP2, proliferation of SSCs and undifferentiated spermatogonia was inhibited, thus germ cells cannot be replenished and SSCs cannot undergo renewal. However, germ cells beyond the undifferentiated spermatogonia stage of development at the time of SHP2 knockout were able to complete their maturation to become sperm. In cultures of SSCs and their progeny, inhibition of SHP2 activity reduced growth factor‐mediated intracellular signaling that regulates SSC proliferation and cell fate. Inhibition of SHP2 also decreased the number of SSCs present in culture and caused SSCs to detach from supporting cells. Injection of mice with an SHP2 inhibitor blocked the production of germ cells from SSCs. Together, our studies show that SHP2 is essential for SSCs to maintain fertility and indicates that the pathogenesis of infertility in humans with SHP2 mutations is due to compromised SSC functions that block spermatogenesis. S tem  C ells   2014;32:741–75
Sowing the Seeds of a Fruitful Harvest: Hematopoietic Stem Cell Mobilization

Hematopoietic stem cell transplantation is the only curative option for a number of malignant and non-malignant diseases. As the use of hematopoietic transplant has expanded, so too has the source of stem and progenitor cells. The predominate source of stem and progenitors today, particularly in settings of autologous transplantation, is mobilized peripheral blood. This review will highlight the historical advances which lead to the widespread use of peripheral blood stem cells for transplantation, with a look towards future enhancements to mobilization strategies
Stress Hematopoiesis Is Regulated by the Krüppel‐Like Transcription Factor ZBP‐89

Previous studies have shown that ZBP‐89 (Zfp148) plays a critical role in erythroid lineage development, with its loss at the embryonic stage causing lethal anemia and thrombocytopenia. Its role in adult hematopoiesis has not been described. We now show that conditional deletion of ZBP‐89 in adult mouse hematopoietic stem/progenitor cells (HSPC) causes anemia and thrombocytopenia that are transient in the steady state, but readily uncovered following chemically induced erythro/megakaryopoietic stress. Unexpectedly, stress induced by bone marrow transplantation of  ZBP89 −  /  −   HSPC also resulted in a myeloid‐to‐B lymphoid lineage switch in bone marrow recipients. The erythroid and myeloid/B lymphoid lineage anomalies in  ZBP89 −  /  −   HSPC are reproduced in vitro in the  ZBP‐89 ‐silenced multipotent hematopoietic cell line FDCP‐Mix A4, and are associated with the upregulation of  PU.1  and downregulation of  SCL/Tal1  and  GATA‐1  in ZBP89‐deficient cells. Chromatin immunoprecipitation and luciferase reporter assays show that ZBP‐89 is a direct repressor of  PU.1  and activator of  SCL/Tal1  and  GATA‐1 . These data identify an important role for ZBP‐89 in regulating stress hematopoiesis in adult mouse bone marrow. S tem  C ells   2014;32:791–80
SIRT1 positively regulates autophagy and mitochondria function in embryonic stem cells under oxidative stress

SIRT1, an NAD-dependent deacetylase, plays a role in regulation of autophagy. SIRT1 increases mitochondrial function and reduces oxidative stress, and has been linked to age-related reactive oxygen species (ROS) generation, which is highly dependent on mitochondrial metabolism. H2O2 induces oxidative stress and autophagic cell death through interference with Beclin 1 and the mTOR signaling pathways. We evaluated connections between SIRT1 activity and induction of autophagy in murine (m) and human (h) embryonic stem cells (ESCs) upon ROS challenge. Exogenous H2 O2 (1 mM) induced apoptosis and autophagy in wild-type (WT) and Sirt1-/- mESCs. High concentrations of H2O2 (1 mM) induced more apoptosis in Sirt1-/-, than in WT mESCs. However, addition of 3-methyladenine, a widely used autophagy inhibitor, in combination with H2O2 induced more cell death in WT than in Sirt1-/- mESCs. Decreased induction of autophagy in Sirt1-/- mESCs was demonstrated by decreased conversion of LC3-I to LC3-II, lowered expression of Beclin-1, and decreased LC3 punctae and LysoTracker staining. H2O2 induced autophagy with loss of mitochondrial membrane potential and disruption of mitochondrial dynamics in Sirt1-/- mESCs. Increased phosphorylation of P70/85-S6 kinase and ribosomal S6 was noted in Sirt1-/- mESCs, suggesting that SIRT1 regulates the mTOR pathway. Consistent with effects in mESCs, inhibition of SIRT1 using Lentivirus-mediated SIRT1 shRNA in hESCs demonstrated that knockdown of SIRT1 decreased H2O2-induced autophagy. This suggests a role for SIRT1 in regulating autophagy and mitochondria function in ESCs upon oxidative stress, effects mediated at least in part by the class III PI3K/Beclin 1 and mTOR pathways
PRL2/PTP4A2 phosphatase is important for hematopoietic stem cell self-renewal

Hematopoietic stem cell (HSC) self-renewal is tightly controlled by cytokines and other signals in the microenvironment. While stem cell factor (SCF) is an early acting cytokine that activates the receptor tyrosine kinase KIT and promotes HSC maintenance, how SCF/KIT signaling is regulated in HSCs is poorly understood. The protein tyrosine phosphatase 4A (PTP4A) family (aka PRL [phosphatase of regenerating liver] phosphatases), consisting of PTP4A1/PRL1, PTP4A2/PRL2, and PTP4A3/PRL3, represents an intriguing group of phosphatases implicated in cell proliferation and tumorigenesis. However, the role of PTP4A in hematopoiesis remains elusive. To define the role of PTP4A in hematopoiesis, we analyzed HSC behavior in Ptp4a2 (Prl2) deficient mice. We found that Ptp4a2 deficiency impairs HSC self-renewal as revealed by serial bone marrow transplantation assays. Moreover, we observed that Ptp4a2 null hematopoietic stem and progenitor cells (HSPCs) are more quiescent and show reduced activation of the AKT and ERK signaling. Importantly, we discovered that the ability of PTP4A2 to enhance HSPC proliferation and activation of AKT and ERK signaling depends on its phosphatase activity. Furthermore, we found that PTP4A2 is important for SCF-mediated HSPC proliferation and loss of Ptp4a2 decreased the ability of oncogenic KIT/D814V mutant in promoting hematopoietic progenitor cell proliferation. Thus, PTP4A2 plays critical roles in regulating HSC self-renewal and mediating SCF/KIT signaling
Human adipose derived stromal/stem cells (hASCs) protect against STZ-induced hyperglycemia; analysis of hASC-derived paracrine effectors

Adipose-derived stromal/stem cells (ASCs) ameliorate hyperglycemia in rodent models of islet transplantation and autoimmune diabetes, yet the precise human ASC (hASC)-derived factors responsible for these effects remain largely unexplored. Here, we show that systemic administration of hASCs improved glucose tolerance, preserved β cell mass, and increased β cell proliferation in streptozotocin-treated nonobese diabetic/severe combined immunodeficient mice. Coculture experiments combining mouse or human islets with hASCs demonstrated that islet viability and function were improved by hASCs following prolonged culture or treatment with proinflammatory cytokines. Analysis of hASC-derived factors revealed vascular endothelial growth factor and tissue inhibitor of metalloproteinase 1 (TIMP-1) to be highly abundant factors secreted by hASCs. Notably, TIMP-1 secretion increased in the presence of islet stress from cytokine treatment, while TIMP-1 blockade was able to abrogate in vitro prosurvival effects of hASCs. Following systemic administration by tail vein injection, hASCs were detected in the pancreas and human TIMP-1 was increased in the serum of injected mice, while recombinant TIMP-1 increased viability in INS-1 cells treated with interleukin-1beta, interferon-gamma, and tumor necrosis factor alpha. In aggregate, our data support a model whereby factors secreted by hASCs, such as TIMP-1, are able to mitigate against β cell death in rodent and in vitro models of type 1 diabetes through a combination of local paracrine as well as systemic effects
Restoring Akt1 activity in outgrowth endothelial cells from South Asian men rescues vascular reparative potential

Recent data suggest reduced indices of vascular repair in South Asian men, a group at increased risk of cardiovascular events. Outgrowth endothelial cells (OEC) represent an attractive tool to study vascular repair in humans and may offer potential in cell-based repair therapies. We aimed to define and manipulate potential mechanisms of impaired vascular repair in South Asian (SA) men. In vitro and in vivo assays of vascular repair and angiogenesis were performed using OEC derived from SA men and matched European controls, prior defining potentially causal molecular mechanisms. SA OEC exhibited impaired colony formation, migration, and in vitro angiogenesis, associated with decreased expression of the proangiogenic molecules Akt1 and endothelial nitric oxide synthase (eNOS). Transfusion of European OEC into immunodeficient mice after wire-induced femoral artery injury augmented re-endothelialization, in contrast with SA OEC and vehicle; SA OEC also failed to promote angiogenesis after induction of hind limb ischemia. Expression of constitutively active Akt1 (E17KAkt), but not green fluorescent protein control, in SA OEC increased in vitro angiogenesis, which was abrogated by a NOS antagonist. Moreover, E17KAkt expressing SA OEC promoted re-endothelialization of wire-injured femoral arteries, and perfusion recovery of ischemic limbs, to a magnitude comparable with nonmanipulated European OEC. Silencing Akt1 in European OEC recapitulated the functional deficits noted in SA OEC. Reduced signaling via the Akt/eNOS axis is causally linked with impaired OEC-mediated vascular repair in South Asian men. These data prove the principle of rescuing marked reparative dysfunction in OEC derived from these men
Endothelial Interleukin‐6 Defines the Tumorigenic Potential of Primary Human Cancer Stem Cells

Head and neck squamous cell carcinomas (HNSCC) contain a small subpopulation of stem cells endowed with unique capacity to generate tumors. These cancer stem cells (CSC) are localized in perivascular niches and rely on crosstalk with endothelial cells for survival and self‐renewal, but the mechanisms involved are unknown. Here, we report that stromal interleukin (IL)−6 defines the tumorigenic capacity of CSC sorted from primary human HNSCC and transplanted into mice. In search for the cellular source of Interleukin‐6 (IL‐6), we observed a direct correlation between IL‐6 levels in tumor‐associated endothelial cells and the tumorigenicity of CSC. In vitro, endothelial cell‐IL‐6 enhanced orosphere formation, p‐STAT3 activation, survival, and self‐renewal of human CSC. Notably, a humanized anti‐IL‐6R antibody (tocilizumab) inhibited primary human CSC‐mediated tumor initiation. Collectively, these data demonstrate that endothelial cell‐secreted IL‐6 defines the tumorigenic potential of CSC, and suggest that HNSCC patients might benefit from therapeutic inhibition of IL‐6/IL‐6R signaling. S tem  C ells   2014;32:2845–285
Concise reviews: in vitro-produced pancreas organogenesis models in three dimensions: self-organization from few stem cells or progenitors.

Three-dimensional models of organ biogenesis have recently flourished. They promote a balance between stem/progenitor cell expansion and differentiation without the constraints of flat tissue culture vessels, allowing for autonomous self-organization of cells. Such models allow the formation of miniature organs in a dish and are emerging for the pancreas, starting from embryonic progenitors and adult cells. This review focuses on the currently available systems and how these allow new types of questions to be addressed. We discuss the expected advancements including their potential to study human pancreas development and function as well as to develop diabetes models and therapeutic cells
Notch Signaling Regulates Motor Neuron Differentiation of Human Embryonic Stem Cells

In the pMN domain of the spinal cord, Notch signaling regulates the balance between motor neuron differentiation and maintenance of the progenitor state for later oligodendrocyte differentiation. Here, we sought to study the role of Notch signaling in regulation of the switch from the pMN progenitor state to differentiated motor neurons in a human model system. Human embryonic stem cells (hESCs) were directed to differentiate to pMN‐like progenitor cells by the inductive action of retinoic acid and a Shh agonist, purmorphamine. We found that the expression of the Notch signaling effector Hes5 was induced in hESC‐derived pMN‐like progenitors and remained highly expressed when they were cultured under conditions favoring motor neuron differentiation. Inhibition of Notch signaling by a γ‐secretase inhibitor in the differentiating pMN‐like progenitor cells decreased Hes5 expression and enhanced the differentiation toward motor neurons. Conversely, over‐expression of Hes5 in pMN‐like progenitor cells during the differentiation interfered with retinoic acid‐ and purmorphamine‐induced motor neuron differentiation and inhibited the emergence of motor neurons. Inhibition of Notch signaling had a permissive rather than an inductive effect on motor neuron differentiation. Our results indicate that Notch signaling has a regulatory role in the switch from the pMN progenitor to the differentiated motor neuron state. Inhibition of Notch signaling can be harnessed to enhance the differentiation of hESCs toward motor neurons. Stem Cells 2015;33:403–41
Acute Loss of Cited2 Impairs Nanog Expression and Decreases Self-Renewal of Mouse Embryonic Stem Cells

Identifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2, and Nanog as well as delineating the interactions within the complex network is key to understanding self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC functions remains unclear. Here, we show that Cited2 is important for proliferation, survival, and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression. Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse embryonic fibroblasts to induced pluripotent stem cells.National Portuguese through FCT-Fundacao para a Ciencia e a Tecnologia [PEst-OE/EQB/LA0023/2013, PTDC/SAU-ENB/111702/2009]; Camara Municipal de Oeiras; Merck Sharp & Dhome Foundation-Portugal; CRUK; Leukaemia & Lymphoma Research; Kay Kendall Leukaemia Fund; Wellcome Trust; Medical Research Council; Cancer Research UK [12796, 14633]; Great Ormond Street Hospital Childrens Charity [W1062]; Medical Research Council [MC_U137973817, G1000801g, MC_qA137913
Acute Loss of Cited2 Impairs Nanog Expression and Decreases Self-Renewal of Mouse Embryonic Stem Cells

Identifying novel players of the pluripotency gene regulatory network centered on Oct4, Sox2,
and Nanog as well as delineating the interactions within the complex network is key to understanding
self-renewal and early cell fate commitment of embryonic stem cells (ESC). While overexpression
of the transcriptional regulator Cited2 sustains ESC pluripotency, its role in ESC
functions remains unclear. Here, we show that Cited2 is important for proliferation, survival,
and self-renewal of mouse ESC. We position Cited2 within the pluripotency gene regulatory network
by defining Nanog, Tbx3, and Klf4 as its direct targets. We also demonstrate that the
defects caused by Cited2 depletion are, at least in part, rescued by Nanog constitutive expression.
Finally, we demonstrate that Cited2 is required for and enhances reprogramming of mouse
embryonic fibroblasts to induced pluripotent stem cells.This work was supported by National Portuguese funding
through FCT—Fundac¸~ao para a Ci^encia e a Tecnologia, projects
PEst-OE/EQB/LA0023/2013 and PTDC/SAU-ENB/111702/
2009, the Young investigator award from the C^amara Municipal
de Oeiras and an award from the Merck Sharp & Dhome
Foundation—Portugal to J.B. K.R.K. is a CRUK Senior Cancer
Research Fellow. Work in KRK’s laboratory is funded by CRUK,
Leukaemia & Lymphoma Research, the Kay Kendall Leukaemia
Fund, the Wellcome Trust, and the Medical Research Council.
We thank Shoumo Bhattacharya (University of Oxford) for Cited2
fl/fl mice, Austin Smith (University of Cambridge) for
E14TG2A and E14/T cells, pPyCAGIP and pPyCAGIP-Nanog,
Tommaso Russo (Universit a degli Studi di Napoli Federico II)
for pNanog-luc and pOct4-luc, Marie-Annick Buendia (INSERM,
Paul Brousse Hospital) for LTBX3-luc, Rui Jian (Third Military
Medical University) for pDoubNeo, and Gustavo Tiscornia
(University of Algarve) for LV-Cre2AGFP. J.B. is grateful to
Paula Alves for sharing resources and equipment in the Animal
Cell Technology group (IBET).This is the final published version. It first appeared at http://onlinelibrary.wiley.com/doi/10.1002/stem.1889/abstract