Pluripotent stem cells are able to self-renew indefinitely and differentiate into all types of cells in the body.They can thus be an inexhaustible source for future cell transplantation therapy to treat degenerative d...Pluripotent stem cells are able to self-renew indefinitely and differentiate into all types of cells in the body.They can thus be an inexhaustible source for future cell transplantation therapy to treat degenerative diseases which currently have no cure.However,non-autologous cells will cause immune rejection.Induced pluripotent stem cell(iPSC)technology can convert somatic cells to the pluripotent state,and therefore offers a solution to this problem.Since the first generation of iPSCs,there has been an explosion of relevant research,from which we have learned much about the genetic networks and epigenetic landscape of pluripotency,as well as how to manipulate genes,epigenetics,and microRNAs to obtain iPSCs.In this review,we focus on the mechanism of cellular reprogramming and current methods to induce pluripotency.We also highlight new problems emerging from iPSCs.Better understanding of the fundamental mechanisms underlying pluripotenty and refining the methodology of iPSC generation will have a significant impact on future development of regenerative medicine.展开更多
Primitive mammalian heart transforms from a single tube to a four-chambered muscular organ during a short developmental window.We found that knocking out global microRNA by deleting Dgcr8 microprocessor in Mespl cardi...Primitive mammalian heart transforms from a single tube to a four-chambered muscular organ during a short developmental window.We found that knocking out global microRNA by deleting Dgcr8 microprocessor in Mespl cardiovascular progenitor cells lead to the formation of extremely dilated and enlarged heart due to defective cardiomyocyte(CM)differentiation.Transcriptome analysis revealed unusual upregulation of vascular gene expression in Dgcr8 cKO hearts.Single cell RNA sequencing study further confirmed the increase of angiogenesis genes in single Dgcr8 cKO CM.We also performed global microRNA profiling of E9.5 heart for the first time,and identified that miR-541 was transiently highly expressed in E9.5 hearts.Interestingly,introducing miR-541 back into microRNA-free CMs partially rescued their defects,downregulated angiogenesis genes and significantly upregulated cardiac genes.Moreover,miR-541 can target Ctgf and inhibit endothelial function.Our results suggest that micro-RNAs are required to suppress abnormal angiogenesis gene program to maintain CM differentiation.展开更多
Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aur...Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B (AurkB) is ubiquitously expressed while Aurora kinase C (AurkC) is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 (H3S10P) and regulate metaphase timing. Using an Oct4-photoactivat- able GFP fusion protein (Oct4-paGFP) and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.展开更多
文摘Pluripotent stem cells are able to self-renew indefinitely and differentiate into all types of cells in the body.They can thus be an inexhaustible source for future cell transplantation therapy to treat degenerative diseases which currently have no cure.However,non-autologous cells will cause immune rejection.Induced pluripotent stem cell(iPSC)technology can convert somatic cells to the pluripotent state,and therefore offers a solution to this problem.Since the first generation of iPSCs,there has been an explosion of relevant research,from which we have learned much about the genetic networks and epigenetic landscape of pluripotency,as well as how to manipulate genes,epigenetics,and microRNAs to obtain iPSCs.In this review,we focus on the mechanism of cellular reprogramming and current methods to induce pluripotency.We also highlight new problems emerging from iPSCs.Better understanding of the fundamental mechanisms underlying pluripotenty and refining the methodology of iPSC generation will have a significant impact on future development of regenerative medicine.
基金the National Key R&D Program of China,grants 2017YFA0102802 and 2016YFC0900100 to J.Na and J.Wangthe National Natural Science Foundation of China(NSFC)grants 91740115,21675098 and 31471222 to J.Na,J.Wang and Y.Wang+1 种基金the National Basic Research Program of China,grant 2012CB966701 to J.Nathe funding from Tsinghua-Peking Center for Life Sciences and core facilities of Tsinghua-Peking Center for Life Sciences.
文摘Primitive mammalian heart transforms from a single tube to a four-chambered muscular organ during a short developmental window.We found that knocking out global microRNA by deleting Dgcr8 microprocessor in Mespl cardiovascular progenitor cells lead to the formation of extremely dilated and enlarged heart due to defective cardiomyocyte(CM)differentiation.Transcriptome analysis revealed unusual upregulation of vascular gene expression in Dgcr8 cKO hearts.Single cell RNA sequencing study further confirmed the increase of angiogenesis genes in single Dgcr8 cKO CM.We also performed global microRNA profiling of E9.5 heart for the first time,and identified that miR-541 was transiently highly expressed in E9.5 hearts.Interestingly,introducing miR-541 back into microRNA-free CMs partially rescued their defects,downregulated angiogenesis genes and significantly upregulated cardiac genes.Moreover,miR-541 can target Ctgf and inhibit endothelial function.Our results suggest that micro-RNAs are required to suppress abnormal angiogenesis gene program to maintain CM differentiation.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (Grant No. 31171381), NSFC-MRC China-UK collaborative project grant 81261130320, the Beijing Natural Science Foundation grant 20151100084 (J.N.), the National Basic Research Program (973 Program) (Nos. 2016YFC0900301 and 2015CB856201 ), the Youth Thousand Scholar Program of China (W.X.), and the funding from the Tsinghua-Peking Center for Life Sciences (W.X., J.N.). We thank the animal facility, SLSTH-Nikon Biological Imaging Center of Tsinghua University for assistance with fluorescence imaging and Dr. Richard de Grijs for helpful comments and English language editing of the manuscript. All authors have contributed to, read, and approved the manuscript for submission.
文摘Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B (AurkB) is ubiquitously expressed while Aurora kinase C (AurkC) is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 (H3S10P) and regulate metaphase timing. Using an Oct4-photoactivat- able GFP fusion protein (Oct4-paGFP) and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.