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Stem cells,including cancer stem cells (CSCs),require niches to maintain stemness,yet it is unclear how CSCs maintain stemness in the suboptimal environment outside their niches during invasion. Postnatal co-deletion of Pten and Trp53 in mouse neural stem cells (NSCs) leads to the expansion of these cells in their subventricular zone (SVZ) niches but fails to maintain stemness outside the SVZ. We discovered that Qki is a major regulator of NSC stemness. Qk deletion on a Pten-/-; Trp53-/- background helps NSCs maintain their stemness outside the SVZ in Nes-CreERT2; QkL/L; PtenL/L; Trp53L/L mice,which develop glioblastoma with a penetrance of 92% and a median survival time of 105 d. Mechanistically,Qk deletion decreases endolysosome-mediated degradation and enriches receptors essential for maintaining self-renewal on the cytoplasmic membrane to cope with low ligand levels outside niches. Thus,downregulation of endolysosome levels by Qki loss helps glioma stem cells (GSCs) maintain their stemness in suboptimal environments outside their niches. View Publication

Despite the high incidence of trophoblast-related diseases,the molecular mechanism of inadequate early trophoblast development is still unclear due to the lack of an appropriate cellular model in vitro. In the present study,we reprogrammed the amniotic cells to be induced pluripotent stem cells (iPSCs) via a non-virus and non-integrated method and subsequently differentiated them into trophoblast-like cells by a modified BMP4 strategy in E6 medium. Compared with the previously studied trophoblast-like cells from ESCs,the iPSCs derived trophoblast-like cells behave similarly in terms of gene expression profiles and biofunctions. Also we confirmed the differentiating tendency from iPSCs to be syncytiotrophoblasts-like cells might be caused by inappropriate differentiating oxygen condition. Additionally,we preliminarily indicated in vitro artificial" differentiation of iPSCs also undergoing a possible trophoblastic stem cell stage as witnessed in vivo. In conclusion we provided an in vitro cellular model to study early trophoblast development for specific individual by using the feasible amnion. View Publication

Nuclear RNA foci are molecular hallmarks of myotonic dystrophy type 1 (DM1). However,no designated study has investigated their formation and changes in proliferating cells. Proliferating cells,as stem cells,consist of an important cellular pool in the human body. The revelation of foci changes in these cells might shed light on the effects of the mutation on these specific cells and tissues. In this study,we used human DM1 iPS-cell-derived neural stem cells (NSCs) as cellular models to investigate the formation and dynamic changes of RNA foci in proliferating cells. Human DM1 NSCs derived from human DM1 iPS cells were cultured under proliferation conditions and nonproliferation conditions following mitomycin C treatment. The dynamic changes of foci during the cell cycle were investigated by fluorescence in situ hybridization. We found RNA foci formed and dissociated during the cell cycle. Nuclear RNA foci were most prominent in number and size just prior to entering mitosis (early prophase). During mitosis,most foci disappeared. After entering interphase,RNA foci accumulated again in the nuclei. After stopping cell dividing by treatment of mitomycin C,the number of nuclear RNA foci increased significantly. In summary,DM1 NSC nuclear RNA foci undergo dynamic changes during cell cycle,and mitosis is a mechanism to decrease foci load in the nuclei,which may explain why dividing cells are less affected by the mutation. The dynamic changes need to be considered when using foci as a marker to monitor the effects of therapeutic drugs. View Publication

Low cell recovery rate of human embryonic stem cells (hESCs) resulting from cryopreservation damages leads to the difficulty in their successful commercialization of clinical applications. Hence in this study,sensitivity of human embryonic stem cells (hESCs) to different cooling rates,ice seeding and cryoprotective agent (CPA) types was compared and cell viability and recovery after cryopreservation under different cooling conditions were assessed. Both extracellular and intracellular ice formation were observed. Reactive oxidative species (ROS) accumulation of hESCs was determined. Cryopreservation of hESCs at 1 °C/min with the ice seeding and at the theoretically predicted optimal cooling rate (TPOCR) led to lower level of intracellular ROS,and prevented irregular and big ice clump formation compared with cryopreservation at 1 °C/min. This strategy further resulted in a significant increase in the hESC recovery when glycerol and 1,2-propanediol were used as the CPAs,but no increase for Me2SO. hESCs after cryopreservation under all the tested conditions still maintained their pluripotency. Our results provide guidance for improving the hESC cryopreservation recovery through the combination of CPA type,cooling rate and ice seeding. View Publication

This study investigates the electrophysiological properties and functional integration of different phenotypes of transplanted human neural precursor cells (hNPCs) in immunodeficient NSG mice. Postnatal day 2 mice received unilateral injections of 100,000 GFP+ hNPCs into the right parietal cortex. Eight weeks after transplantation,1.21% of transplanted hNPCs survived. In these hNPCs,parvalbumin (PV)-,calretinin (CR)-,somatostatin (SS)-positive inhibitory interneurons and excitatory pyramidal neurons were confirmed electrophysiologically and histologically. All GFP+ hNPCs were immunoreactive with anti-human specific nuclear protein. The proportions of PV-,CR-,and SS-positive cells among GFP+ cells were 35.5%,15.7%,and 17.1%,respectively; around 15% of GFP+ cells were identified as pyramidal neurons. Those electrophysiologically and histological identified GFP+ hNPCs were shown to fire action potentials with the appropriate firing patterns for different classes of neurons and to display spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs). The amplitude,frequency and kinetic properties of sEPSCs and sIPSCs in different types of hNPCs were comparable to host cells of the same type. In conclusion,GFP+ hNPCs produce neurons that are competent to integrate functionally into host neocortical neuronal networks. This provides promising data on the potential for hNPCs to serve as therapeutic agents in neurological diseases with abnormal neuronal circuitry such as epilepsy. View Publication

Glioblastoma multiforme (GBM) is an aggressive,Grade IV astrocytoma with a poor survival rate,primarily due to the GBM tumor cells migrating away from the primary tumor site along the nanotopography of white matter tracts and blood vessels. It is unclear whether this nanotopography influences the biomechanical properties (i.e. cytoskeletal stiffness) of GBM tumor cells. Although GBM tumor cells have an innate propensity to migrate,we believe this capability is enhanced due to the influence of nanotopography on the tumor cells' biomechanical properties. In this study,we used an aligned nanofiber film that mimics the nanotopography in the tumor microenvironment to investigate the mechanical properties of GBM tumor cells in vitro. The data demonstrate that the cytoskeletal stiffness,cell traction stress,and focal adhesion area were significantly lower in the GBM tumor cells compared to healthy astrocytes. Moreover,the cytoskeletal stiffness was significantly reduced when cultured on aligned nanofiber films compared to smooth and randomly aligned nanofiber films. Gene expression analysis showed that tumor cells cultured on the aligned nanotopography upregulated key migratory genes and downregulated key proliferative genes. Therefore,our data suggest that the migratory potential is elevated when GBM tumor cells are migrating along aligned nanotopographical substrates. View Publication

Glioblastoma multiforme (GBM) is the most common primary malignant adult brain tumor and is associated with poor survival. Recently,stem-like cell populations have been identified in numerous malignancies including GBM. To identify genes whose expression is changed with differentiation,we compared transcript profiles from a GBM oncosphere line before and after differentiation. Bioinformatic analysis of the gene expression profiles identified podocalyxin-like protein (PODXL),a protein highly expressed in human embryonic stem cells,as a potential marker of undifferentiated GBM stem-like cells. The loss of PODXL expression upon differentiation of GBM stem-like cell lines was confirmed by quantitative real-time PCR and flow cytometry. Analytical flow cytometry of numerous GBM oncosphere lines demonstrated PODXL expression in all lines examined. Knockdown studies and flow cytometric cell sorting experiments demonstrated that PODXL is involved in GBM stem-like cell proliferation and oncosphere formation. Compared to PODXL-negative cells,PODXL-positive cells had increased expression of the progenitor/stem cell markers Musashi1,SOX2,and BMI1. Finally,PODXL expression directly correlated with increasing glioma grade and was a marker for poor outcome in patients with GBM. In summary,we have demonstrated that PODXL is expressed in GBM stem-like cells and is involved in cell proliferation and oncosphere formation. Moreover,high PODXL expression correlates with increasing glioma grade and decreased overall survival in patients with GBM. View Publication

Adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are good candidates for cell therapy due to the accessibility of fat tissue and the abundance of AT-MSCs therein. Neurospheres are free-floating spherical condensations of cells with neural stem/progenitor cell (NSPC) characteristics that can be derived from AT-MSCs. The aims of this study were to examine the influence of oxygen (O2) tension on generation of neurospheres from canine AT-MSCs (AT-cMSCs) and to develop a hypoxic cell culture system to enhance the survival and therapeutic benefit of generated neurospheres. AT-cMSCs were cultured under varying oxygen tensions (1%,5% and 21%) in a neurosphere culture system. Neurosphere number and area were evaluated and NSPC markers were quantified using real-time quantitative PCR (qPCR). Effects of oxygen on neurosphere expression of hypoxia inducible factor 1,α subunit (HIF1A) and its target genes,erythropoietin receptor (EPOR),chemokine (C-X-C motif) receptor 4 (CXCR4) and vascular endothelial growth factor (VEGF),were quantified by qPCR. Neural differentiation potential was evaluated in 21% O2 by cell morphology and qPCR. Neurospheres were successfully generated from AT-cMSCs at all O2 tensions. Expression of nestin mRNA (NES) was significantly increased after neurosphere culture and was significantly higher in 1% O2 compared to 5% and 21% O2. Neurospheres cultured in 1% O2 had significantly increased levels of VEGF and EPOR. There was a significant increase in CXCR4 expression in neurospheres generated at all O2 tensions. Neurosphere culture under hypoxia had no negative effect on subsequent neural differentiation. This study suggests that generation of neurospheres under hypoxia could be beneficial when considering these cells for neurological cell therapies. View Publication

Respiratory syncytial virus (RSV) causes severe respiratory disease in young children. Antibodies specific for the RSV prefusion F protein have guided RSV vaccine research,and in human serum,these antibodies contribute to<90% of the neutralization response; however,detailed insight into the composition of the human B cell repertoire against RSV is still largely unknown. In order to study the B cell repertoire of three healthy donors for specificity against RSV,CD27+memory B cells were isolated and immortalized using BCL6 and Bcl-xL. Of the circulating memory B cells,0.35% recognized RSV-A2-infected cells,of which 59% were IgA-expressing cells and 41% were IgG-expressing cells. When we generated monoclonal B cells selected for high binding to RSV-infected cells,44.5% of IgG-expressing B cells and 56% of IgA-expressing B cells reacted to the F protein,while,unexpectedly,41.5% of IgG-expressing B cells and 44% of IgA expressing B cells reacted to the G protein. Analysis of the G-specific antibodies revealed that 4 different domains on the G protein were recognized. These epitopes predicted cross-reactivity between RSV strain A (RSV-A) and RSV-B and matched the potency of antibodies to neutralize RSV in HEp-2 cells and in primary epithelial cell cultures. G-specific antibodies were also able to induce antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis of RSV-A2-infected cells. However,these processes did not seem to depend on a specific epitope. In conclusion,healthy adults harbor a diverse repertoire of RSV glycoprotein-specific antibodies with a broad range of effector functions that likely play an important role in antiviral immunity.IMPORTANCEHuman RSV remains the most common cause of severe lower respiratory tract disease in premature babies,young infants,the elderly,and immunocompromised patients and plays an important role in asthma exacerbations. In developing countries,RSV lower respiratory tract disease has a high mortality. Without an effective vaccine,only passive immunization with palivizumab is approved for prophylactic treatment. However,highly potent RSV-specific monoclonal antibodies could potentially serve as a therapeutic treatment and contribute to disease control and mortality reduction. In addition,these antibodies could guide further vaccine development. In this study,we isolated and characterized several novel antibodies directed at the RSV G protein. This information can add to our understanding and treatment of RSV disease. View Publication

Realization of clinical potential of human pluripotent stem cells (hPSCs) in bone regenerative medicine requires development of simple and safe biomaterials for expansion of hPSCs followed by directing their lineage commitment to osteoblasts. In the present study,a chemically defined peptide-decorated polycaprolactone (PCL) nanofibrous microenvironment was prepared through electrospinning technology and subsequent conjugation with vitronectin peptide to promote the culture and osteogenic potential of hPSCs in vitro. The results indicated that hPSCs successfully proliferated and maintained their pluripotency on the biointerface of peptide-conjugated nanofibers without Matrigel under defined conditions. Moreover,the prepared niche exhibited an appealing ability in promoting directed differentiation of hPSCs to osteoblastic phenotype without embryoid body formation step,determined from the cell morphological alteration,alkaline phosphate activity,and osteogenesis-related gene expression,as well as protein production. Such well-defined,xeno-free,and safe nanofiber scaffolds that allow the survival and facilitate osteo-differentiation of hPSCs provide a novel platform for hPSCs differentiation via cell-nanofiber interplay,and possess great value in accelerating the translational perspectives of hPSCs in bone tissue engineering. View Publication

Several progenitor cell populations have been reported to exist in hearts that play a role in cardiac turnover and/or repair. Despite the presence of cardiac stem and progenitor cells within the myocardium,functional repair of the heart after injury is inadequate. Identification of the signaling pathways involved in the expansion and differentiation of cardiac progenitor cells (CPCs) will broaden insight into the fundamental mechanisms playing a role in cardiac homeostasis and disease and might provide strategies for in vivo regenerative therapies. To understand and exploit cardiac ontogeny for drug discovery efforts,we developed an in vitro human induced pluripotent stem cell-derived CPC model system using a highly enriched population of KDR(pos)/CKIT(neg)/NKX2.5(pos) CPCs. Using this model system,these CPCs were capable of generating highly enriched cultures of cardiomyocytes under directed differentiation conditions. In order to facilitate the identification of pathways and targets involved in proliferation and differentiation of resident CPCs,we developed phenotypic screening assays. Screening paradigms for therapeutic applications require a robust,scalable,and consistent methodology. In the present study,we have demonstrated the suitability of these cells for medium to high-throughput screens to assess both proliferation and multilineage differentiation. Using this CPC model system and a small directed compound set,we identified activin-like kinase 5 (transforming growth factor-β type 1 receptor kinase) inhibitors as novel and potent inducers of human CPC differentiation to cardiomyocytes. Significance: Cardiac disease is a leading cause of morbidity and mortality,with no treatment available that can result in functional repair. This study demonstrates how differentiation of induced pluripotent stem cells can be used to identify and isolate cell populations of interest that can translate to the adult human heart. Two separate examples of phenotypic screens are discussed,demonstrating the value of this biologically relevant and reproducible technology. In addition,this assay system was able to identify novel and potent inducers of differentiation and proliferation of induced pluripotent stem cell-derived cardiac progenitor cells. View Publication

Little is known about monocyte differentiation in the lung mucosal environment and about how the epithelium shapes monocyte function. We studied the role of the soluble component of bronchial epithelial cells (BECs) obtained under basal culture conditions in innate and adaptive monocyte responses. Monocytes cultured in bronchial epithelial cell-conditioned media (BEC-CM) specifically upregulate CD141,CD123,and DC-SIGN surface levels andFLT3expression,as well as the release of IL-1β,IL-6,and IL-10. BEC-conditioned monocytes stimulate naive T cells to produce IL-17 through IL-1β mechanism and also trigger IL-10 production by memory T cells. Furthermore,monocytes cultured in an inflammatory environment induced by the cytokines IL-6,IL-8,IL-1β,IL-15,TNF-α,and GM-CSF also upregulate CD123 and DC-SIGN expression. However,only inflammatory cytokines in the epithelial environment boost the expression of CD141. Interestingly,we identified a CD141/CD123/DC-SIGN triple positive population in the bronchoalveolar lavage fluid (BALF) from patients with different inflammatory conditions,demonstrating that this monocyte population existsin vivo. The frequency of this monocyte population was significantly increased in patients with sarcoidosis,suggesting a role in inflammatory mechanisms. Overall,these data highlight the specific role that the epithelium plays in shaping monocyte responses. Therefore,the unraveling of these mechanisms contributes to the understanding of the function that the epithelium may playin vivo. View Publication