Spinal cord impairment involving motor neuron degeneration and demyelination can cause lifelong disabilities,but effective clinical interventions for restoring neurological functions have yet to be developed.In early ...Spinal cord impairment involving motor neuron degeneration and demyelination can cause lifelong disabilities,but effective clinical interventions for restoring neurological functions have yet to be developed.In early spinal cord development,neural progenitors of the motor neuron(pMN)domain,defined by the expression of oligodendrocyte transcription factor 2(OLIG2),in the ventral spinal cord first generate motor neurons and then switch the fate to produce myelin-forming oligodendrocytes.Given their differentiation potential,pMN progenitors could be a valuable cell source for cell therapy in relevant neurological conditions such as spinal cord injury.However,fast generation and expansion of pMN progenitors in vitro while conserving their differentiation potential has so far been technically challenging.In this study,based on chemical screening,we have developed a new recipe for efficient induction of pMN progenitors from human embryonic stem cells.More importantly,these OLIG2+pMN progenitors can be stably maintained for multiple passages without losing their ability to produce spinal motor neurons and oligodendrocytes rapidly.Our results suggest that these self-renewing pMN progenitors could potentially be useful as a renewable source of cell transplants for spinal cord injury and demyelinating disorders.展开更多
N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis a...N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis and neural regeneration, where it is highly concentrated and actively involved in these processes. Changes in m^(6)A modification levels and the expression levels of related enzymatic proteins can lead to neurological dysfunction and contribute to the development of neurological diseases. Furthermore, the proliferation and differentiation of neural stem cells, as well as nerve regeneration, are intimately linked to memory function and neurodegenerative diseases. This paper presents a comprehensive review of the roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, as well as its implications in memory and neurodegenerative diseases. m^(6)A has demonstrated divergent effects on the proliferation and differentiation of neural stem cells. These observed contradictions may arise from the time-specific nature of m^(6)A and its differential impact on neural stem cells across various stages of development. Similarly, the diverse effects of m^(6)A on distinct types of memory could be attributed to the involvement of specific brain regions in memory formation and recall. Inconsistencies in m^(6)A levels across different models of neurodegenerative disease, particularly Alzheimer's disease and Parkinson's disease, suggest that these disparities are linked to variations in the affected brain regions. Notably, the opposing changes in m^(6)A levels observed in Parkinson's disease models exposed to manganese compared to normal Parkinson's disease models further underscore the complexity of m^(6)A's role in neurodegenerative processes. The roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, and its implications in memory and neurodegenerative diseases, appear contradictory. These inconsistencies may be attributed to the timespecific nature of m^(6)A and its varying effects on distinct brain regions and in different environments.展开更多
AIM： To identify cancer stern cells （CSCs） in human gallbladder carcinomas （GBCs）. METHODS： Primary GBC cells were cultured under serum-free conditions to produce floating spheres. The stem-cell properties of th...AIM： To identify cancer stern cells （CSCs） in human gallbladder carcinomas （GBCs）. METHODS： Primary GBC cells were cultured under serum-free conditions to produce floating spheres. The stem-cell properties of the sphere-forming cells, including self-renewal, differentiation potential, chemoresistance and tumorigenicity, were determined in vitro or in vivo. Cell surface expression of CD133 was investigated in primary tumors and in spheroid cells using flow cytometry. The sphere-colony-formation ability and tumorigenicity of CD133＋ cells were assayed.floating spheroids were generated from primary GBC cells, and these sphere-forming cells could generate new progeny spheroids in serum-free media. Spheroid cells were differentiated under serum-containing conditions with downregulation of the stem cell markers Oct-4, Nanog, and nestin （P 〈 0.05）. The differentiated cells showed lower spheroid-colony-formation ability than the original spheroid cells （P 〈 0.05）. Spheroid ceils were more resistant to chemotherapeutic reagents than the congenetic adherent cells （P 〈 0.05）. Flow cytometry showed enriched CD133＋ population in sphereforming cells （P 〈 0.05）. CD133＋ cells possessed high colony-formation ability than the CD133 population （P 〈 0.01）. CD133＋ cells injected into nude mice revealed higher tumorigenicity than their antigen-negative counterparts （P 〈 0.05）. CONCLUSION： CD133 may be a cell surface marker for CSCs in GBC.展开更多
AIM： To investigate the effect of activation of canonical Wnt signaling pathway on the proliferation and differentiation of hepatic oval cells in vitro. METHODS： WB-F344 cells were treated with recombinant Wnt3a （2...AIM： To investigate the effect of activation of canonical Wnt signaling pathway on the proliferation and differentiation of hepatic oval cells in vitro. METHODS： WB-F344 cells were treated with recombinant Wnt3a （20, 40, 80, 160, 200 ng/mL） in serum-free medium for 24 h. Cell proliferation was measured by Brdu incorporation analysis; untreated WB-F344 cells were taken as controls. After treatment with Wnt3a （160 ng/mL） for 24 h, subcellular localization and protein expression of p-catenin in WB-F344 cells treated and untreated with Wnt3a were examined by immunofluorescence staining and Western blot analysis. CyclinD1 mRNA expression was determined by semi-quantitative reverse-transcript polymerase chain reaction （RT-PCR）. The mRNA levels of some phenotypic markers （AFP, CK-19, ALB） and two hepatic nuclear factors （HNF-4, HIVF-6） were measured by RT-PCR. Expressions of CK-19 and AFP protein were detected by Western blot analysis. RESULTS： Wnt3a promoted proliferation of WB-F344 cells. Stimulation of WB-F344 cells with recombinant Wnt3a resulte^l in accumulation of the transcriptional activator β-catenin, together with its translocation into the nuclei, and up-regulated typical Wnt target gene CyclinD1. After 3 d of Wnt3a treatment in the absence of serum, WB-F344 cells retained their bipotential to express several specific phenotypic markers of hepatocytes and cholangiocytes, such as AFP and CK-19, following activation of the canonical Wnt signaling pathway. CONCLUSION： The canonical Wnt signaling pathway promotes proliferation and self-renewal of rat hepatic oval cells.展开更多
Spermatogonial stem cells （SSCs）, the stem cells responsible for male fertility, are one of a small number of cells with the abilities of both self-renewal and generation of large numbers of haploid cells. Technolog...Spermatogonial stem cells （SSCs）, the stem cells responsible for male fertility, are one of a small number of cells with the abilities of both self-renewal and generation of large numbers of haploid cells. Technology improvements, most importantly, transplantation assays and in vitro culture systems have greatly expanded our understanding of SSC self-renewal and differentiation. Many important molecules crucial for the balance between self-renewal and differentiation have been recently identified although the exact mechanism（s） remain largely undefined. In this review, we give a brief introduction to SSCs, and then focus on extrinsic and intrinsic factors controlling SSCs self-renewal and differentiation.展开更多
A key issue to be addressed in stem cell biology is the molecular signaling mechanism controlling embryonic stem （ES） cell pluripotency. Stem cell properties are dictated by specific transcription factors and epigen...A key issue to be addressed in stem cell biology is the molecular signaling mechanism controlling embryonic stem （ES） cell pluripotency. Stem cell properties are dictated by specific transcription factors and epigenetic processes such as DNA methylation and chromatin remodeling. Several cytokines/growth factors have been identified as critical ES cell regulators. However, there is a gap in our knowledge of the intracellular signaling pathways linking extracellular signals to transcriptional regulation in ES cells. This short review discusses the physiological role of Shp2, a cytoplasmic tyro- sine phosphatase, in the molecular switch governing ES cell self-renewal versus differentiation. Shp2 promotes ES cell differentiation, mainly through bi-directional modulation of Erk and Stat3 pathways. Deletion of Shp2 in mouse ES cells results in more efficient self-renewal. This observation provides the impetus to develop Shp2 inhibitors for maintenance and amplification of ES cells in culture.展开更多
BACKGROUND Cellular metabolism regulates stemness in health and disease.A reduced redox state is essential for self-renewal of normal and cancer stem cells(CSCs).However,while stem cells rely on glycolysis,different C...BACKGROUND Cellular metabolism regulates stemness in health and disease.A reduced redox state is essential for self-renewal of normal and cancer stem cells(CSCs).However,while stem cells rely on glycolysis,different CSCs,including pancreatic CSCs,favor mitochondrial metabolism as their dominant energy-producing pathway.This suggests that powerful antioxidant networks must be in place to detoxify mitochondrial reactive oxygen species(ROS)and maintain stemness in oxidative CSCs.Since glutathione metabolism is critical for normal stem cell function and CSCs from breast,liver and gastric cancer show increased glutathione content,we hypothesized that pancreatic CSCs also rely on this pathway for ROS detoxification.AIM To investigate the role of glutathione metabolism in pancreatic CSCs.METHODS Primary pancreatic cancer cells of patient-derived xenografts(PDXs)were cultured in adherent or CSC-enriching sphere conditions to determine the role of glutathione metabolism in stemness.Real-time polymerase chain reaction(PCR)was used to validate RNAseq results involving glutathione metabolism genes in adherent vs spheres,as well as the expression of pluripotency-related genes following treatment.Public TCGA and GTEx RNAseq data from pancreatic cancer vs normal tissue samples were analyzed using the webserver GEPIA2.The glutathione-sensitive fluorescent probe monochlorobimane was used to determine glutathione content by fluorimetry or flow cytometry.Pharmacological inhibitors of glutathione synthesis and recycling[buthionine-sulfoximine(BSO)and 6-Aminonicotinamide(6-AN),respectively]were used to investigate the impact of glutathione depletion on CSC-enriched cultures.Staining with propidium iodide(cell cycle),Annexin-V(apoptosis)and CD133(CSC content)were determined by flow cytometry.Self-renewal was assessed by sphere formation assay and response to gemcitabine treatment was used as a readout for chemoresistance.RESULTS Analysis of our previously published RNAseq dataset E-MTAB-3808 revealed upregulation of genes involved in the KEGG(Kyoto Encyclopedia of Genes and Genomes)Pathway Glutathione Metabolism in CSC-enriched cultures compared to their differentiated counterparts.Consistently,in pancreatic cancer patient samples the expression of most of these up-regulated genes positively correlated with a stemness signature defined by NANOG,KLF4,SOX2 and OCT4 expression(P<10-5).Moreover,3 of the upregulated genes(MGST1,GPX8,GCCT)were associated with reduced disease-free survival in patients[Hazard ratio(HR)2.2-2.5;P=0.03-0.0054],suggesting a critical role for this pathway in pancreatic cancer progression.CSC-enriched sphere cultures also showed increased expression of different glutathione metabolism-related genes,as well as enhanced glutathione content in its reduced form(GSH).Glutathione depletion with BSO induced cell cycle arrest and apoptosis in spheres,and diminished the expression of stemness genes.Moreover,treatment with either BSO or the glutathione recycling inhibitor 6-AN inhibited self-renewal and the expression of the CSC marker CD133.GSH content in spheres positively correlated with intrinsic resistance to gemcitabine treatment in different PDXs r=0.96,P=5.8×1011).Additionally,CD133+cells accumulated GSH in response to gemcitabine,which was abrogated by BSO treatment(P<0.05).Combined treatment with BSO and gemcitabine-induced apoptosis in CD133+cells to levels comparable to CD133-cells and significantly diminished self-renewal(P<0.05),suggesting that chemoresistance of CSCs is partially dependent on GSH metabolism.CONCLUSION Our data suggest that pancreatic CSCs depend on glutathione metabolism.Pharmacological targeting of this pathway showed that high GSH content is essential to maintain CSC functionality in terms of self-renewal and chemoresistance.展开更多
Long non-coding RNAs(lncRNAs)regulate transcription to control development and homeostasis in a variety of tissues and organs.However,their roles in the development of the cerebral cortex have not been well elucidated...Long non-coding RNAs(lncRNAs)regulate transcription to control development and homeostasis in a variety of tissues and organs.However,their roles in the development of the cerebral cortex have not been well elucidated.Here,a bioinformatics pipeline was applied to delineate the dynamic expression and potential cis-regulating effects of mouse lncRNAs using transcriptome data from 8 embryonic time points and sub-regions of the developing cerebral cortex.We further characterized a sense lncRNA,SenZfp536,which is transcribed downstream of and partially overlaps with the protein-coding gene Zfp536.Both SenZfp536 and Zfp536 were predominantly expressed in the proliferative zone of the developing cortex.Zfp536 was cis-regulated by SenZfp536,which facilitates looping between the promoter of Zfp536 and the genomic region that transcribes SenZfp536.Surprisingly,knocking down or activating the expression of SenZfp536 increased or compromised the proliferation of cortical neural progenitor cells(NPCs),respectively.Finally,overexpressing Zfp536 in cortical NPCs reversed the enhanced proliferation of cortical NPCs caused by SenZfp536 knockdown.The study deepens our understanding of how lncRNAs regulate the propagation of cortical NPCs through cis-regulatory mechanisms.展开更多
In this Editorial review,we would like to focus on a very recent discovery showing the global autosomal gene regulation by Y-and inactivated X-chromosomal transcription factors,zinc finger gene on the Y chromosome(ZFY...In this Editorial review,we would like to focus on a very recent discovery showing the global autosomal gene regulation by Y-and inactivated X-chromosomal transcription factors,zinc finger gene on the Y chromosome(ZFY)and zinc finger protein X-linked(ZFX).ZFX and ZFY are both zinc-finger proteins that encode general transcription factors abundant in hematopoietic and embryonic stem cells.Although both proteins are homologs,interestingly,the regulation of self-renewal by these transcriptional factors is almost exclusive to ZFX.This fact implies that there are some differential roles between ZFX and ZFY in regulating the maintenance of self-renewal activity in stem cells.Besides the maintenance of stemness,ZFX overexpression or mutations may be linked to certain cancers.Although cancers and stem cells are double-edged swords,there is no study showing the link between ZFX activity and the telomere.Thus,stemness or cancers with ZFX may be linked to other molecules,such as Oct4,Sox2,Klf4,and others.Based on very recent studies and a few lines of evidence in the past decade,it appears that the ZFX is linked to the canonical Wnt signaling,which is one possible mechanism to explain the role of ZFX in the self-renewal of stem cells.展开更多
Cancer stem cells(CSCs)possess self-renewal and differentiation potential,which may be related to recurrence,metastasis,and radiochemotherapy resistance during tumor treatment.Understanding the mechanisms via which CS...Cancer stem cells(CSCs)possess self-renewal and differentiation potential,which may be related to recurrence,metastasis,and radiochemotherapy resistance during tumor treatment.Understanding the mechanisms via which CSCs maintain self-renewal may reveal new therapeutic targets for attenuating CSC resistance and extending patient life-span.Recent studies have shown that amino acid metabolism plays an important role in maintaining the self-renewal of CSCs and is involved in regulating their tumorigenicity characteristics.This review summarizes the relationship between CSCs and amino acid metabolism,and discusses the possible mechanisms by which amino acid metabolism regulates CSC characteristics particularly self-renewal,survival and stemness.The ultimate goal is to identify new targets and research directions for elimination of CSCs.展开更多
The origin of macrophages has been considered since several decades to be a continuum from bone marrow （BM） to tissue via monocytes as precursors. The development of new tools such as genetic lineage tracing,parabio...The origin of macrophages has been considered since several decades to be a continuum from bone marrow （BM） to tissue via monocytes as precursors. The development of new tools such as genetic lineage tracing,parabiosis and BM chimeras changed the paradigm of macrophage origin. In steady state, most resident macro-phages are of embryonic origin, whereas a monocyte origin remains prominent in pathological conditions. The findings of a proliferation of mature macrophages will oblige us to reappraise the relationship between proliferation and differentiation in macrophages. This review is based on the recent explosion of high impact articles on macrophage biology. It summarizes new data on the origin of macrophages and their self-renewal potential in steady states. While monocytes are required for intestinal macrophage development, the microglia is independent of monocyte influx and skin macrophages provide an excellent model of the balance between monocyte input and self-renewal. In addition, macrophage proliferation requires intrinsic and extrinsic factors including growth factors and cytokines. It also analyzes the impact of this new paradigm in human diseases such as athrosclerosis, cancer, infe-ctious diseases and neurodegenerative diseases. In atherosclerosis, the fnding of macrophage proliferation within the lesions will change our understanding of disease pathophysiology, this new paradigm may have therapeutical impact in the future.展开更多
Background Bone marrow mesenchymal stem cells （BMSCs） can be isolated and cultured to many passages However, Stem cells including BMSCs quickly undergo senescence in culture. The cell senescence and multidirectional...Background Bone marrow mesenchymal stem cells （BMSCs） can be isolated and cultured to many passages However, Stem cells including BMSCs quickly undergo senescence in culture. The cell senescence and multidirectional differentiation have hampered producing BMSCs in quantity with their undifferentiated state. In this study we report a natural compound, vitamin C （Vc）, maintains BMSCs stem property. Methods Human BMSCs were isolated from bone marrow and purified by 1.073 g/mL density gradient centrifugation. 50 ng/mL Vc were added to BMSCs for different time point. Flowcytometry was used to detect cell surface markers of BMSCs with or without Vc treatment. BMSCs proliferation was analyzed by MTF assay. PCR（polymerase chain reaction） and real-time PCR were used for detecting c-kit, nanog, and Oct-4 genes expression levels. DNA methyltransferase （Dnmt） 1 and Dnmt3b levels were also detected by real-time PCR. Results Flowcytometry showed that after Vc treatment for 6 h, the surface markers of BMSCs were almost unchanged. Vc increased the proliferation activity of BMSCs from 6h to 24 h. PCR showed the expression of c-kit, nanog, and oct-4 genes were obviously increased c-kit, nanog, and oct-4 in Vc treated group than control group at 12 h. Real-time PCR showed that the level of genes were unregulated from 6h to 12h compared with control group. Vc also increased Dnmt3b but not Dnmtl gene expression. Conclusions Our results showed Vc acts at least accelerates BMSCs proliferation and maintains stem cell property. In our study BMSCs generation and provided additional insights into the we highlighted a method of improving the speed of mechanistic basis of preventing BMSCs senescence展开更多
BACKGROUND The Warburg effect is common in cancers.Lactate and its receptor GPR81 play an important role in cancer progression.It is widely accepted that membrane receptor nuclear translocation plays some novel role i...BACKGROUND The Warburg effect is common in cancers.Lactate and its receptor GPR81 play an important role in cancer progression.It is widely accepted that membrane receptor nuclear translocation plays some novel role in cancer pathology.The mechanism by which the lactate/GPR81 axis regulates cancer malignancy remains unclear.AIM To elucidate the mechanism of GPR81 nuclear transportation promoted by exogenous lactate.METHODS Lung cancer cells were stimulated with exogenous lactate and GPR81 levels were measured by immunofluoresence and western blot analysis in membrane,cytoplasmic,and nuclear fractions.Lung cancer cells were transduced with a mutant GPR81 nuclear localization signal(NLS)construct,wild type GPR81 or empty vector and used to examine how GPR81 nuclear transportation affects lung cancer cells malignancy in vitro and in vivo.Immunoprecipitation Proteomics analysis and Chromatin immunoprecipitation(ChIP)sequencing were used to determine GPR81 interacting proteins and genes.RESULTS In response to hypoxia/Lactate stimulation,GPR81 translocates and accumulates in the nucleus of lung cancer cells.Functionally,GPR81 nuclear translocation promotes cancer cell proliferation and motility.Depletion of the GPR81 NLS depletes GPR81 nuclear levels and decreases cancer cell growth and invasion in vitro,as well as cancer cell malignancy in vivo.Proteomics analysis revealed a set of proteins including SFPQ,that interact with GPR81 in the cancer cell nucleus.Notably,the interaction of GPR81 with SFPQ promotes cancer cell growth and motility.ChIP sequencing analysis discovered that there is a set of genes targeted by GPR81.CONCLUSION The interaction of GPR81 with SFPQ promotes cancer cell malignancy.GPR81 nuclear translocation is critical in conferring cancer progression and may be a potential therapeutic target for limiting cancer progression.展开更多
Embryonic stem(ES)cells are characterized by their ability to indefinitely self-renew and potential to differentiate into all the cell lineages of the body.ES cells are considered to have potential applications in reg...Embryonic stem(ES)cells are characterized by their ability to indefinitely self-renew and potential to differentiate into all the cell lineages of the body.ES cells are considered to have potential applications in regenerative medicine.In particular,the emergence of an ES cell analogue-induced pluripotent stem(iPS)cells via somatic cell reprogramming by co-expressing a limited number of critical stemness-related transcriptional factors has solved the problem of obtaining patient-specific pluripotent cells,encouraging researchers to develop more specific and functional cell lineages from ES or iPS cells for broad therapeutic applications.ES cell fate choice is delicately controlled by a core transcriptional network,epigenetic modification profiles and complex signaling cascades both intrinsically and extrinsically.Of these signals,transforming growth factorβ(TGF-β)family members,including TGF-β,bone morphogenetic protein(BMP),Activin and Nodal,have been reported to influence cell self-renewal and a broad spectrum of lineage differentiation in ES cells,in accordance with the key roles of TGF-βfamily signaling in early embryo development.In this review,the roles of TGF-βfamily signals in coordinating ES cell fate determination are summarized.展开更多
Wnt signaling has been implicated in the control over various types of stem cells and may act as a niche factor to maintain stem cells in a self-renewing state. As currently understood, Wnt proteins bind to receptors ...Wnt signaling has been implicated in the control over various types of stem cells and may act as a niche factor to maintain stem cells in a self-renewing state. As currently understood, Wnt proteins bind to receptors of the Frizzled and LRP families on the cell surface. Through several cytoplasmic relay components, the signal is transduced to β-catenin, which then enters the nucleus and forms a complex with TCF to activate transcription of Wnt target genes. Wnts can also signal through tyrosine kinase receptors, in particular the ROR and RYK receptors, leading to alternative modes of Wnt signaling. During the growth of tissues, these ligands and receptors are dynamically expressed, often transcriptionally controlled by Wnt signals themselves, to ensure the right balance between proliferation and differentiation. Isolated Wnt proteins are active on a variety of stem cells, including neural, mammary and embryonic stem cells. In general, Wnt proteins act to maintain the undifferentiated state of stem cells, while other growth factors instruct the cells to proliferate. These other factors include FGF and EGF, signaling through tyrosine kinase pathways.展开更多
In our previous study, five homologous feeder cell lines, Monkey ear skin fibroblasts （MESFs）, clonally derived fibroblasts from the MESFs （CMESFs）, monkey oviductal fibroblasts （MOFs）, monkey follicular granulo...In our previous study, five homologous feeder cell lines, Monkey ear skin fibroblasts （MESFs）, clonally derived fibroblasts from the MESFs （CMESFs）, monkey oviductal fibroblasts （MOFs）, monkey follicular granulosa fibroblast-like （MFGs） cells, monkey follicular granulosa epithelium-like （MFGEs） cells, were developed for the maintenance of rhesus embryonic stem cells （rESCs）. We found that MESFs, CMESFs, MOFs and MFGs, but not MFGEs, support the growth of rhesus embryonic stem cells. Moreover, we detected some genes that are upregulated in supportive feeder cell lines by semi-quantitative PCR. In the present study, we applied the GeneChip Rhesus Macaque Genome Array of Affymetrix Corporation to study the expression profiles of these five feeder cell lines, in purpose to find out which cytokines and signaling pathways were important in maintaining the rESCs, mRNAs of eight genes, including GREM2, bFGF, KITLG, DKK3, GREM1, AREG, SERPINF1 and LTBP1, were found to be upregulated in supportive feeder cell lines, but not in MFGE. The results indicate that many signaling pathways may play redundant roles in supporting the undifferentiated growth and maintenance of pluripotency in rESCs.展开更多
AIM:To evaluate whether 8-bromo-7-methoxychrysin(BrMC),a synthetic analogue of chrysin,inhibits the properties of cancer stem cells derived from the human liver cancer MHCC97 cell line and to determine the potential m...AIM:To evaluate whether 8-bromo-7-methoxychrysin(BrMC),a synthetic analogue of chrysin,inhibits the properties of cancer stem cells derived from the human liver cancer MHCC97 cell line and to determine the potential mechanisms.METHODS:CD133+cells were sorted from the MHCC97 cell line by magnetic activated cell sorting,and amplified in stem cell-conditioned medium to obtain the enriched CD133+sphere forming cells(SFCs).The stem cell properties of CD133+SFCs were validated by the tumorsphere formation assay in vitro and the xenograft nude mouse model in vivo,and termed liver cancer stem cells(LCSCs).The effects of BrMC on LCSCs in vitro were evaluated by MTT assay,tumorsphere formation assay and transwell chamber assay.The effects of BrMC on LCSCs in vivo were determined using a primary and secondary xenograft model in Balb/c-nu mice.Expressions of the stem cell markers,epithelialmesenchymal transition(EMT)markers andβ-catenin protein were analyzed by western blotting or immunohistochemical analysis.RESULTS:CD133+SFCs exhibited stem-like cell properties of tumorsphere formation and tumorigenesis capacity in contrast to the parental MHCC97 cells.We found that BrMC preferentially inhibited proliferation and self-renewal of LCSCs(P<0.05).Furthermore,BrMC significantly suppressed EMT and invasion of LCSCs.Moreover,BrMC could efficaciously eliminate LCSCs in vivo.Interestingly,we showed that BrMC decreased the expression ofβ-catenin in LCSCs.Silencing ofβ-catenin by small interfering RNA could synergize the inhibition of self-renewal of LCSCs induced by BrMC,while Wnt3a treatment antagonized the inhibitory effects of BrMC.CONCLUSION:BrMC can inhibit the functions and characteristics of LCSCs derived from the liver cancer MHCC97 cell line through downregulation ofβ-catenin expression.展开更多
Mounting evidence in stem cell biology has shown that microRNAs(miRNAs) play a crucial role in cell fate specification, including stem cell self-renewal, lineagespecific differentiation, and somatic cell reprogramming...Mounting evidence in stem cell biology has shown that microRNAs(miRNAs) play a crucial role in cell fate specification, including stem cell self-renewal, lineagespecific differentiation, and somatic cell reprogramming.These functions are tightly regulated by specific gene expression patterns that involve miRNAs and transcription factors. To maintain stem cell pluripotency, specific miRNAs suppress transcription factors that promote differentiation, whereas to initiate differentiation, lineagespecific miRNAs are upregulated via the inhibition of transcription factors that promote self-renewal. Small molecules can be used in a similar manner as natural miRNAs, and a number of natural and synthetic small molecules have been isolated and developed to regulate stem cell fate. Using miRNAs as novel regulators of stem cell fate will provide insight into stem cell biology and aid in understanding the molecular mechanisms and crosstalk between miRNAs and stem cells.Ultimately, advances in the regulation of stem cell fate will contribute to the development of effective medical therapies for tissue repair and regeneration. This review summarizes the current insights into stem cell fate determination by miRNAs with a focus on stem cell self-renewal, differentiation, and reprogramming. Small molecules that control stem cell fate are also highlighted.展开更多
Mesenchymal stem cells(MSCs)have been widely exploited as promising candidates in clinical settings for bone repair and regeneration in view of their self-renewal capacity and multipotentiality.However,little is known...Mesenchymal stem cells(MSCs)have been widely exploited as promising candidates in clinical settings for bone repair and regeneration in view of their self-renewal capacity and multipotentiality.However,little is known about the mechanisms underlying their fate determination,which would illustrate their effectiveness in regenerative medicine.Recent evidence has shed light on a fundamental biological role of autophagy in the maintenance of the regenerative capability of MSCs and bone homeostasis.Autophagy has been implicated in provoking an immediately available cytoprotective mechanism in MSCs against stress,while dysfunction of autophagy impairs the function of MSCs,leading to imbalances of bone remodeling and a wide range of aging and degenerative bone diseases.This review aims to summarize the up-to-date knowledge about the effects of autophagy on MSC fate determination and its role as a stress adaptation response.Meanwhile,we highlight autophagy as a dynamic process and a double-edged sword to account for some discrepancies in the current research.We also discuss the contribution of autophagy to the regulation of bone cells and bone remodeling and emphasize its potential involvement in bone disease.展开更多
Embryonic stem cells （ESCs） hold great promises for treating and studying numerous devastating diseases. The molecular basis of their potential is not completely understood. Large noncoding RNAs （lncRNAs） are an i...Embryonic stem cells （ESCs） hold great promises for treating and studying numerous devastating diseases. The molecular basis of their potential is not completely understood. Large noncoding RNAs （lncRNAs） are an important class of gene regulators that play essential roles in a variety of physiologic and pathologic processes. Dozens of lncRNAs are now identified to control ESC self-renewal and differentiation. Research on lncRNAs may provide novel insights into manipulating the cell fate or reprogramming somatic cells into induced pluripotent stem cells （iPSCs）. In this review, we summarize the recent research efforts in identifying functional lncRNAs and understanding how they act in ESCs, and discuss various future directions of this field.展开更多
基金unding This study was supported by grants from the National Key R&D Program of China(2018YFA0107200 and 2020YFA0113101)the National Natural Science Foundation of China(81571094,81322016,32070866,and 31771643)+4 种基金the Program of Shanghai Academic Research Leader(17XD1404800)the Biotechnology and Biological Sciences Research Council(BB/S000844/1 and BB/S008934/1)Newton Advanced Fellowship(AMS-NAF1-Li),Shanghai Science and Technology Committee(19JC1413200)the program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning(1710000009)the Shanghai Key Laboratory of Reproductive Medicine.
文摘Spinal cord impairment involving motor neuron degeneration and demyelination can cause lifelong disabilities,but effective clinical interventions for restoring neurological functions have yet to be developed.In early spinal cord development,neural progenitors of the motor neuron(pMN)domain,defined by the expression of oligodendrocyte transcription factor 2(OLIG2),in the ventral spinal cord first generate motor neurons and then switch the fate to produce myelin-forming oligodendrocytes.Given their differentiation potential,pMN progenitors could be a valuable cell source for cell therapy in relevant neurological conditions such as spinal cord injury.However,fast generation and expansion of pMN progenitors in vitro while conserving their differentiation potential has so far been technically challenging.In this study,based on chemical screening,we have developed a new recipe for efficient induction of pMN progenitors from human embryonic stem cells.More importantly,these OLIG2+pMN progenitors can be stably maintained for multiple passages without losing their ability to produce spinal motor neurons and oligodendrocytes rapidly.Our results suggest that these self-renewing pMN progenitors could potentially be useful as a renewable source of cell transplants for spinal cord injury and demyelinating disorders.
基金supported by the Natural Science Foundation of Heilongjiang Province of China,Outstanding Youth Foundation,No.YQ2022H003 (to DW)。
文摘N6-methyladenosine(m^(6)A), the most prevalent and conserved RNA modification in eukaryotic cells, profoundly influences virtually all aspects of mRNA metabolism. mRNA plays crucial roles in neural stem cell genesis and neural regeneration, where it is highly concentrated and actively involved in these processes. Changes in m^(6)A modification levels and the expression levels of related enzymatic proteins can lead to neurological dysfunction and contribute to the development of neurological diseases. Furthermore, the proliferation and differentiation of neural stem cells, as well as nerve regeneration, are intimately linked to memory function and neurodegenerative diseases. This paper presents a comprehensive review of the roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, as well as its implications in memory and neurodegenerative diseases. m^(6)A has demonstrated divergent effects on the proliferation and differentiation of neural stem cells. These observed contradictions may arise from the time-specific nature of m^(6)A and its differential impact on neural stem cells across various stages of development. Similarly, the diverse effects of m^(6)A on distinct types of memory could be attributed to the involvement of specific brain regions in memory formation and recall. Inconsistencies in m^(6)A levels across different models of neurodegenerative disease, particularly Alzheimer's disease and Parkinson's disease, suggest that these disparities are linked to variations in the affected brain regions. Notably, the opposing changes in m^(6)A levels observed in Parkinson's disease models exposed to manganese compared to normal Parkinson's disease models further underscore the complexity of m^(6)A's role in neurodegenerative processes. The roles of m^(6)A in neural stem cell proliferation, differentiation, and self-renewal, and its implications in memory and neurodegenerative diseases, appear contradictory. These inconsistencies may be attributed to the timespecific nature of m^(6)A and its varying effects on distinct brain regions and in different environments.
文摘AIM： To identify cancer stern cells （CSCs） in human gallbladder carcinomas （GBCs）. METHODS： Primary GBC cells were cultured under serum-free conditions to produce floating spheres. The stem-cell properties of the sphere-forming cells, including self-renewal, differentiation potential, chemoresistance and tumorigenicity, were determined in vitro or in vivo. Cell surface expression of CD133 was investigated in primary tumors and in spheroid cells using flow cytometry. The sphere-colony-formation ability and tumorigenicity of CD133＋ cells were assayed.floating spheroids were generated from primary GBC cells, and these sphere-forming cells could generate new progeny spheroids in serum-free media. Spheroid cells were differentiated under serum-containing conditions with downregulation of the stem cell markers Oct-4, Nanog, and nestin （P 〈 0.05）. The differentiated cells showed lower spheroid-colony-formation ability than the original spheroid cells （P 〈 0.05）. Spheroid ceils were more resistant to chemotherapeutic reagents than the congenetic adherent cells （P 〈 0.05）. Flow cytometry showed enriched CD133＋ population in sphereforming cells （P 〈 0.05）. CD133＋ cells possessed high colony-formation ability than the CD133 population （P 〈 0.01）. CD133＋ cells injected into nude mice revealed higher tumorigenicity than their antigen-negative counterparts （P 〈 0.05）. CONCLUSION： CD133 may be a cell surface marker for CSCs in GBC.
文摘AIM： To investigate the effect of activation of canonical Wnt signaling pathway on the proliferation and differentiation of hepatic oval cells in vitro. METHODS： WB-F344 cells were treated with recombinant Wnt3a （20, 40, 80, 160, 200 ng/mL） in serum-free medium for 24 h. Cell proliferation was measured by Brdu incorporation analysis; untreated WB-F344 cells were taken as controls. After treatment with Wnt3a （160 ng/mL） for 24 h, subcellular localization and protein expression of p-catenin in WB-F344 cells treated and untreated with Wnt3a were examined by immunofluorescence staining and Western blot analysis. CyclinD1 mRNA expression was determined by semi-quantitative reverse-transcript polymerase chain reaction （RT-PCR）. The mRNA levels of some phenotypic markers （AFP, CK-19, ALB） and two hepatic nuclear factors （HNF-4, HIVF-6） were measured by RT-PCR. Expressions of CK-19 and AFP protein were detected by Western blot analysis. RESULTS： Wnt3a promoted proliferation of WB-F344 cells. Stimulation of WB-F344 cells with recombinant Wnt3a resulte^l in accumulation of the transcriptional activator β-catenin, together with its translocation into the nuclei, and up-regulated typical Wnt target gene CyclinD1. After 3 d of Wnt3a treatment in the absence of serum, WB-F344 cells retained their bipotential to express several specific phenotypic markers of hepatocytes and cholangiocytes, such as AFP and CK-19, following activation of the canonical Wnt signaling pathway. CONCLUSION： The canonical Wnt signaling pathway promotes proliferation and self-renewal of rat hepatic oval cells.
基金ACKNOWLEDGM ENTS This work was supported by National Basic Research Program of China （grant numbers 2013CB967401 http：//www.most.gov.cn） and the National Nature Science Foundation of China （grant numbers 81370675, 81200472 and 81421061+1 种基金 http：//www.nsfc.gov.cn）, and Shanghai Jiao Tong University Medicine-Engineering Fund （grant numberYG2013ZD04 http：//www.sjtu. edu.cn）.
文摘Spermatogonial stem cells （SSCs）, the stem cells responsible for male fertility, are one of a small number of cells with the abilities of both self-renewal and generation of large numbers of haploid cells. Technology improvements, most importantly, transplantation assays and in vitro culture systems have greatly expanded our understanding of SSC self-renewal and differentiation. Many important molecules crucial for the balance between self-renewal and differentiation have been recently identified although the exact mechanism（s） remain largely undefined. In this review, we give a brief introduction to SSCs, and then focus on extrinsic and intrinsic factors controlling SSCs self-renewal and differentiation.
文摘A key issue to be addressed in stem cell biology is the molecular signaling mechanism controlling embryonic stem （ES） cell pluripotency. Stem cell properties are dictated by specific transcription factors and epigenetic processes such as DNA methylation and chromatin remodeling. Several cytokines/growth factors have been identified as critical ES cell regulators. However, there is a gap in our knowledge of the intracellular signaling pathways linking extracellular signals to transcriptional regulation in ES cells. This short review discusses the physiological role of Shp2, a cytoplasmic tyro- sine phosphatase, in the molecular switch governing ES cell self-renewal versus differentiation. Shp2 promotes ES cell differentiation, mainly through bi-directional modulation of Erk and Stat3 pathways. Deletion of Shp2 in mouse ES cells results in more efficient self-renewal. This observation provides the impetus to develop Shp2 inhibitors for maintenance and amplification of ES cells in culture.
文摘BACKGROUND Cellular metabolism regulates stemness in health and disease.A reduced redox state is essential for self-renewal of normal and cancer stem cells(CSCs).However,while stem cells rely on glycolysis,different CSCs,including pancreatic CSCs,favor mitochondrial metabolism as their dominant energy-producing pathway.This suggests that powerful antioxidant networks must be in place to detoxify mitochondrial reactive oxygen species(ROS)and maintain stemness in oxidative CSCs.Since glutathione metabolism is critical for normal stem cell function and CSCs from breast,liver and gastric cancer show increased glutathione content,we hypothesized that pancreatic CSCs also rely on this pathway for ROS detoxification.AIM To investigate the role of glutathione metabolism in pancreatic CSCs.METHODS Primary pancreatic cancer cells of patient-derived xenografts(PDXs)were cultured in adherent or CSC-enriching sphere conditions to determine the role of glutathione metabolism in stemness.Real-time polymerase chain reaction(PCR)was used to validate RNAseq results involving glutathione metabolism genes in adherent vs spheres,as well as the expression of pluripotency-related genes following treatment.Public TCGA and GTEx RNAseq data from pancreatic cancer vs normal tissue samples were analyzed using the webserver GEPIA2.The glutathione-sensitive fluorescent probe monochlorobimane was used to determine glutathione content by fluorimetry or flow cytometry.Pharmacological inhibitors of glutathione synthesis and recycling[buthionine-sulfoximine(BSO)and 6-Aminonicotinamide(6-AN),respectively]were used to investigate the impact of glutathione depletion on CSC-enriched cultures.Staining with propidium iodide(cell cycle),Annexin-V(apoptosis)and CD133(CSC content)were determined by flow cytometry.Self-renewal was assessed by sphere formation assay and response to gemcitabine treatment was used as a readout for chemoresistance.RESULTS Analysis of our previously published RNAseq dataset E-MTAB-3808 revealed upregulation of genes involved in the KEGG(Kyoto Encyclopedia of Genes and Genomes)Pathway Glutathione Metabolism in CSC-enriched cultures compared to their differentiated counterparts.Consistently,in pancreatic cancer patient samples the expression of most of these up-regulated genes positively correlated with a stemness signature defined by NANOG,KLF4,SOX2 and OCT4 expression(P<10-5).Moreover,3 of the upregulated genes(MGST1,GPX8,GCCT)were associated with reduced disease-free survival in patients[Hazard ratio(HR)2.2-2.5;P=0.03-0.0054],suggesting a critical role for this pathway in pancreatic cancer progression.CSC-enriched sphere cultures also showed increased expression of different glutathione metabolism-related genes,as well as enhanced glutathione content in its reduced form(GSH).Glutathione depletion with BSO induced cell cycle arrest and apoptosis in spheres,and diminished the expression of stemness genes.Moreover,treatment with either BSO or the glutathione recycling inhibitor 6-AN inhibited self-renewal and the expression of the CSC marker CD133.GSH content in spheres positively correlated with intrinsic resistance to gemcitabine treatment in different PDXs r=0.96,P=5.8×1011).Additionally,CD133+cells accumulated GSH in response to gemcitabine,which was abrogated by BSO treatment(P<0.05).Combined treatment with BSO and gemcitabine-induced apoptosis in CD133+cells to levels comparable to CD133-cells and significantly diminished self-renewal(P<0.05),suggesting that chemoresistance of CSCs is partially dependent on GSH metabolism.CONCLUSION Our data suggest that pancreatic CSCs depend on glutathione metabolism.Pharmacological targeting of this pathway showed that high GSH content is essential to maintain CSC functionality in terms of self-renewal and chemoresistance.
基金This work was supported by grants from the National Key R&D Program of China(2018YFA0800700)the National Natural Science Foundation of China(31970770,31970676,and 31671418)+2 种基金the Natural Science Foundation of Hubei Province,China(2018CFA016)Fundamental Research Funds for the Central Universities,the Medical Science Advancement Program(Basic Medical Sciences)of Wuhan University(TFJC2018005)State Key Laboratory Special Fund 2060204.
文摘Long non-coding RNAs(lncRNAs)regulate transcription to control development and homeostasis in a variety of tissues and organs.However,their roles in the development of the cerebral cortex have not been well elucidated.Here,a bioinformatics pipeline was applied to delineate the dynamic expression and potential cis-regulating effects of mouse lncRNAs using transcriptome data from 8 embryonic time points and sub-regions of the developing cerebral cortex.We further characterized a sense lncRNA,SenZfp536,which is transcribed downstream of and partially overlaps with the protein-coding gene Zfp536.Both SenZfp536 and Zfp536 were predominantly expressed in the proliferative zone of the developing cortex.Zfp536 was cis-regulated by SenZfp536,which facilitates looping between the promoter of Zfp536 and the genomic region that transcribes SenZfp536.Surprisingly,knocking down or activating the expression of SenZfp536 increased or compromised the proliferation of cortical neural progenitor cells(NPCs),respectively.Finally,overexpressing Zfp536 in cortical NPCs reversed the enhanced proliferation of cortical NPCs caused by SenZfp536 knockdown.The study deepens our understanding of how lncRNAs regulate the propagation of cortical NPCs through cis-regulatory mechanisms.
文摘In this Editorial review,we would like to focus on a very recent discovery showing the global autosomal gene regulation by Y-and inactivated X-chromosomal transcription factors,zinc finger gene on the Y chromosome(ZFY)and zinc finger protein X-linked(ZFX).ZFX and ZFY are both zinc-finger proteins that encode general transcription factors abundant in hematopoietic and embryonic stem cells.Although both proteins are homologs,interestingly,the regulation of self-renewal by these transcriptional factors is almost exclusive to ZFX.This fact implies that there are some differential roles between ZFX and ZFY in regulating the maintenance of self-renewal activity in stem cells.Besides the maintenance of stemness,ZFX overexpression or mutations may be linked to certain cancers.Although cancers and stem cells are double-edged swords,there is no study showing the link between ZFX activity and the telomere.Thus,stemness or cancers with ZFX may be linked to other molecules,such as Oct4,Sox2,Klf4,and others.Based on very recent studies and a few lines of evidence in the past decade,it appears that the ZFX is linked to the canonical Wnt signaling,which is one possible mechanism to explain the role of ZFX in the self-renewal of stem cells.
基金Supported by Capital’s Funds for Health Improvement and Research (CFH),No. 2020-2-2175Beijing Talents Project
文摘Cancer stem cells(CSCs)possess self-renewal and differentiation potential,which may be related to recurrence,metastasis,and radiochemotherapy resistance during tumor treatment.Understanding the mechanisms via which CSCs maintain self-renewal may reveal new therapeutic targets for attenuating CSC resistance and extending patient life-span.Recent studies have shown that amino acid metabolism plays an important role in maintaining the self-renewal of CSCs and is involved in regulating their tumorigenicity characteristics.This review summarizes the relationship between CSCs and amino acid metabolism,and discusses the possible mechanisms by which amino acid metabolism regulates CSC characteristics particularly self-renewal,survival and stemness.The ultimate goal is to identify new targets and research directions for elimination of CSCs.
文摘The origin of macrophages has been considered since several decades to be a continuum from bone marrow （BM） to tissue via monocytes as precursors. The development of new tools such as genetic lineage tracing,parabiosis and BM chimeras changed the paradigm of macrophage origin. In steady state, most resident macro-phages are of embryonic origin, whereas a monocyte origin remains prominent in pathological conditions. The findings of a proliferation of mature macrophages will oblige us to reappraise the relationship between proliferation and differentiation in macrophages. This review is based on the recent explosion of high impact articles on macrophage biology. It summarizes new data on the origin of macrophages and their self-renewal potential in steady states. While monocytes are required for intestinal macrophage development, the microglia is independent of monocyte influx and skin macrophages provide an excellent model of the balance between monocyte input and self-renewal. In addition, macrophage proliferation requires intrinsic and extrinsic factors including growth factors and cytokines. It also analyzes the impact of this new paradigm in human diseases such as athrosclerosis, cancer, infe-ctious diseases and neurodegenerative diseases. In atherosclerosis, the fnding of macrophage proliferation within the lesions will change our understanding of disease pathophysiology, this new paradigm may have therapeutical impact in the future.
基金supported by grants from National Natural Science of Foundation China (Nos. 30900610, 30672077)the National Key Basic Research Program (NKBRP) of China (No.2006CB503806)Guangdong Provincial Natural Science Foundation (Nos. 9451008002003467, 8251008004000001, 06020831,06020821)
文摘Background Bone marrow mesenchymal stem cells （BMSCs） can be isolated and cultured to many passages However, Stem cells including BMSCs quickly undergo senescence in culture. The cell senescence and multidirectional differentiation have hampered producing BMSCs in quantity with their undifferentiated state. In this study we report a natural compound, vitamin C （Vc）, maintains BMSCs stem property. Methods Human BMSCs were isolated from bone marrow and purified by 1.073 g/mL density gradient centrifugation. 50 ng/mL Vc were added to BMSCs for different time point. Flowcytometry was used to detect cell surface markers of BMSCs with or without Vc treatment. BMSCs proliferation was analyzed by MTF assay. PCR（polymerase chain reaction） and real-time PCR were used for detecting c-kit, nanog, and Oct-4 genes expression levels. DNA methyltransferase （Dnmt） 1 and Dnmt3b levels were also detected by real-time PCR. Results Flowcytometry showed that after Vc treatment for 6 h, the surface markers of BMSCs were almost unchanged. Vc increased the proliferation activity of BMSCs from 6h to 24 h. PCR showed the expression of c-kit, nanog, and oct-4 genes were obviously increased c-kit, nanog, and oct-4 in Vc treated group than control group at 12 h. Real-time PCR showed that the level of genes were unregulated from 6h to 12h compared with control group. Vc also increased Dnmt3b but not Dnmtl gene expression. Conclusions Our results showed Vc acts at least accelerates BMSCs proliferation and maintains stem cell property. In our study BMSCs generation and provided additional insights into the we highlighted a method of improving the speed of mechanistic basis of preventing BMSCs senescence
文摘BACKGROUND The Warburg effect is common in cancers.Lactate and its receptor GPR81 play an important role in cancer progression.It is widely accepted that membrane receptor nuclear translocation plays some novel role in cancer pathology.The mechanism by which the lactate/GPR81 axis regulates cancer malignancy remains unclear.AIM To elucidate the mechanism of GPR81 nuclear transportation promoted by exogenous lactate.METHODS Lung cancer cells were stimulated with exogenous lactate and GPR81 levels were measured by immunofluoresence and western blot analysis in membrane,cytoplasmic,and nuclear fractions.Lung cancer cells were transduced with a mutant GPR81 nuclear localization signal(NLS)construct,wild type GPR81 or empty vector and used to examine how GPR81 nuclear transportation affects lung cancer cells malignancy in vitro and in vivo.Immunoprecipitation Proteomics analysis and Chromatin immunoprecipitation(ChIP)sequencing were used to determine GPR81 interacting proteins and genes.RESULTS In response to hypoxia/Lactate stimulation,GPR81 translocates and accumulates in the nucleus of lung cancer cells.Functionally,GPR81 nuclear translocation promotes cancer cell proliferation and motility.Depletion of the GPR81 NLS depletes GPR81 nuclear levels and decreases cancer cell growth and invasion in vitro,as well as cancer cell malignancy in vivo.Proteomics analysis revealed a set of proteins including SFPQ,that interact with GPR81 in the cancer cell nucleus.Notably,the interaction of GPR81 with SFPQ promotes cancer cell growth and motility.ChIP sequencing analysis discovered that there is a set of genes targeted by GPR81.CONCLUSION The interaction of GPR81 with SFPQ promotes cancer cell malignancy.GPR81 nuclear translocation is critical in conferring cancer progression and may be a potential therapeutic target for limiting cancer progression.
基金supported by grants from the National Natural Science Foundation of China(Grant Nos.30921004 and 30930050)the National Basic Research Program of China(Grant Nos of China 2006CB943401,2006CB910102 and 2010CB 833706)
文摘Embryonic stem(ES)cells are characterized by their ability to indefinitely self-renew and potential to differentiate into all the cell lineages of the body.ES cells are considered to have potential applications in regenerative medicine.In particular,the emergence of an ES cell analogue-induced pluripotent stem(iPS)cells via somatic cell reprogramming by co-expressing a limited number of critical stemness-related transcriptional factors has solved the problem of obtaining patient-specific pluripotent cells,encouraging researchers to develop more specific and functional cell lineages from ES or iPS cells for broad therapeutic applications.ES cell fate choice is delicately controlled by a core transcriptional network,epigenetic modification profiles and complex signaling cascades both intrinsically and extrinsically.Of these signals,transforming growth factorβ(TGF-β)family members,including TGF-β,bone morphogenetic protein(BMP),Activin and Nodal,have been reported to influence cell self-renewal and a broad spectrum of lineage differentiation in ES cells,in accordance with the key roles of TGF-βfamily signaling in early embryo development.In this review,the roles of TGF-βfamily signals in coordinating ES cell fate determination are summarized.
文摘Wnt signaling has been implicated in the control over various types of stem cells and may act as a niche factor to maintain stem cells in a self-renewing state. As currently understood, Wnt proteins bind to receptors of the Frizzled and LRP families on the cell surface. Through several cytoplasmic relay components, the signal is transduced to β-catenin, which then enters the nucleus and forms a complex with TCF to activate transcription of Wnt target genes. Wnts can also signal through tyrosine kinase receptors, in particular the ROR and RYK receptors, leading to alternative modes of Wnt signaling. During the growth of tissues, these ligands and receptors are dynamically expressed, often transcriptionally controlled by Wnt signals themselves, to ensure the right balance between proliferation and differentiation. Isolated Wnt proteins are active on a variety of stem cells, including neural, mammary and embryonic stem cells. In general, Wnt proteins act to maintain the undifferentiated state of stem cells, while other growth factors instruct the cells to proliferate. These other factors include FGF and EGF, signaling through tyrosine kinase pathways.
文摘In our previous study, five homologous feeder cell lines, Monkey ear skin fibroblasts （MESFs）, clonally derived fibroblasts from the MESFs （CMESFs）, monkey oviductal fibroblasts （MOFs）, monkey follicular granulosa fibroblast-like （MFGs） cells, monkey follicular granulosa epithelium-like （MFGEs） cells, were developed for the maintenance of rhesus embryonic stem cells （rESCs）. We found that MESFs, CMESFs, MOFs and MFGs, but not MFGEs, support the growth of rhesus embryonic stem cells. Moreover, we detected some genes that are upregulated in supportive feeder cell lines by semi-quantitative PCR. In the present study, we applied the GeneChip Rhesus Macaque Genome Array of Affymetrix Corporation to study the expression profiles of these five feeder cell lines, in purpose to find out which cytokines and signaling pathways were important in maintaining the rESCs, mRNAs of eight genes, including GREM2, bFGF, KITLG, DKK3, GREM1, AREG, SERPINF1 and LTBP1, were found to be upregulated in supportive feeder cell lines, but not in MFGE. The results indicate that many signaling pathways may play redundant roles in supporting the undifferentiated growth and maintenance of pluripotency in rESCs.
基金Supported by National Natural Science Foundation of China,No.81172375Scientific Research Fund of Hunan Normal University,No.81105
文摘AIM:To evaluate whether 8-bromo-7-methoxychrysin(BrMC),a synthetic analogue of chrysin,inhibits the properties of cancer stem cells derived from the human liver cancer MHCC97 cell line and to determine the potential mechanisms.METHODS:CD133+cells were sorted from the MHCC97 cell line by magnetic activated cell sorting,and amplified in stem cell-conditioned medium to obtain the enriched CD133+sphere forming cells(SFCs).The stem cell properties of CD133+SFCs were validated by the tumorsphere formation assay in vitro and the xenograft nude mouse model in vivo,and termed liver cancer stem cells(LCSCs).The effects of BrMC on LCSCs in vitro were evaluated by MTT assay,tumorsphere formation assay and transwell chamber assay.The effects of BrMC on LCSCs in vivo were determined using a primary and secondary xenograft model in Balb/c-nu mice.Expressions of the stem cell markers,epithelialmesenchymal transition(EMT)markers andβ-catenin protein were analyzed by western blotting or immunohistochemical analysis.RESULTS:CD133+SFCs exhibited stem-like cell properties of tumorsphere formation and tumorigenesis capacity in contrast to the parental MHCC97 cells.We found that BrMC preferentially inhibited proliferation and self-renewal of LCSCs(P<0.05).Furthermore,BrMC significantly suppressed EMT and invasion of LCSCs.Moreover,BrMC could efficaciously eliminate LCSCs in vivo.Interestingly,we showed that BrMC decreased the expression ofβ-catenin in LCSCs.Silencing ofβ-catenin by small interfering RNA could synergize the inhibition of self-renewal of LCSCs induced by BrMC,while Wnt3a treatment antagonized the inhibitory effects of BrMC.CONCLUSION:BrMC can inhibit the functions and characteristics of LCSCs derived from the liver cancer MHCC97 cell line through downregulation ofβ-catenin expression.
基金supported by a South Korea Science and Engineering Foundation grant funded by the South Korea government(MEST)(2011-0019243,2011-0019254)a grant from the South Korea Health 21 R and D Project,Ministry of Health and Welfare,South Korea(A120478)a grant from the Korea Health 21 R and D Project,Ministry of Health and Welfare,South Korea(A085136)
文摘Mounting evidence in stem cell biology has shown that microRNAs(miRNAs) play a crucial role in cell fate specification, including stem cell self-renewal, lineagespecific differentiation, and somatic cell reprogramming.These functions are tightly regulated by specific gene expression patterns that involve miRNAs and transcription factors. To maintain stem cell pluripotency, specific miRNAs suppress transcription factors that promote differentiation, whereas to initiate differentiation, lineagespecific miRNAs are upregulated via the inhibition of transcription factors that promote self-renewal. Small molecules can be used in a similar manner as natural miRNAs, and a number of natural and synthetic small molecules have been isolated and developed to regulate stem cell fate. Using miRNAs as novel regulators of stem cell fate will provide insight into stem cell biology and aid in understanding the molecular mechanisms and crosstalk between miRNAs and stem cells.Ultimately, advances in the regulation of stem cell fate will contribute to the development of effective medical therapies for tissue repair and regeneration. This review summarizes the current insights into stem cell fate determination by miRNAs with a focus on stem cell self-renewal, differentiation, and reprogramming. Small molecules that control stem cell fate are also highlighted.
文摘Mesenchymal stem cells(MSCs)have been widely exploited as promising candidates in clinical settings for bone repair and regeneration in view of their self-renewal capacity and multipotentiality.However,little is known about the mechanisms underlying their fate determination,which would illustrate their effectiveness in regenerative medicine.Recent evidence has shed light on a fundamental biological role of autophagy in the maintenance of the regenerative capability of MSCs and bone homeostasis.Autophagy has been implicated in provoking an immediately available cytoprotective mechanism in MSCs against stress,while dysfunction of autophagy impairs the function of MSCs,leading to imbalances of bone remodeling and a wide range of aging and degenerative bone diseases.This review aims to summarize the up-to-date knowledge about the effects of autophagy on MSC fate determination and its role as a stress adaptation response.Meanwhile,we highlight autophagy as a dynamic process and a double-edged sword to account for some discrepancies in the current research.We also discuss the contribution of autophagy to the regulation of bone cells and bone remodeling and emphasize its potential involvement in bone disease.
基金supported by grants from Chinese Ministry of Science and Technology (Nos. 2011CBA01100 and 2012CB966700)the National Natural Science Foundation of China (No. 31221002)
文摘Embryonic stem cells （ESCs） hold great promises for treating and studying numerous devastating diseases. The molecular basis of their potential is not completely understood. Large noncoding RNAs （lncRNAs） are an important class of gene regulators that play essential roles in a variety of physiologic and pathologic processes. Dozens of lncRNAs are now identified to control ESC self-renewal and differentiation. Research on lncRNAs may provide novel insights into manipulating the cell fate or reprogramming somatic cells into induced pluripotent stem cells （iPSCs）. In this review, we summarize the recent research efforts in identifying functional lncRNAs and understanding how they act in ESCs, and discuss various future directions of this field.
