Development of the way how to induce efficient cardiomyocyte differentiation using stem cells and attempt for cell transplantation therapy against heart failure

1)高迁移率族蛋白A(HMGA)家族成员是在胎儿中广泛表达的转录因子。它们通过参与特定的蛋白质-DNA和蛋白质-蛋白质相互作用来调节许多基因的表达，这些相互作用既可以引起染色质底物的结构变化，也可以在靶基因的启动子/增强子区域形成转录复合体。我们证明，HMGA2是HMGA家族的成员，在心肌细胞分化和心脏发育中起着关键作用。HMGA2的稳定过表达可显著促进P19CL6心肌细胞向搏动心肌细胞的分化，而HMGA2的抑制作用则可阻断其向搏动心肌细胞的分化。我们还发现，Smad转录因子与HMGA2形成复合体，与CSX/NKX2.5启动子上进化保守的序列结合，表现出协同转录激活作用。此外，抑制非洲爪哇胚胎中的HMGA2抑制心肌细胞分化…更多和正常的心脏形成，意味着HMGA2在心脏发育中也起着至关重要的作用。2)目前的医学移植面临着供体短缺和地理限制等重大问题，这阻碍了有限供体器官在其保存期内的有效利用。为了克服这些问题，延长器官保存时间已成为一个主要问题。我们研究了是否可以通过使用新开发的冷藏室来实现最好地保存器官移植的策略，该冷藏室能够通过在其内部产生静电场来稳定地建立过冷和解冻状态。成年大鼠的心、肝、肾等器官在过冷条件下保存时，其主要生化标志物的渗漏水平明显低于普通低温保存。过冷保存后未见明显的组织学损伤。我们的结果表明，这种过冷冰箱的使用改善了器官保存，并可能为人类器官移植提供一种创新的技术。较少

1) Members of the high-mobility-group proteins A (HMGA) family are transcription factors expressed ubiquitously in fetus. They regulate expression of numerous genes by participating in specific protein-DNA and protein-protein interactions that induce both structural changes in chromatin substrates and the formation of transcriptional complexes on the promoter/enhancer region of their target genes. We demonstrated that HMGA2, a member of the HMGA family, plays a critical role in cardiomyocyte differentiation and cardiac development. Stable overexpression of HMGA2 strongly enhanced the differentiation of the P19CL6 cardiomyogenic cell line into beating cardiomyocytes while its inhibition blocked it. We also found that the Smad transcription factors and HMGA2 formed complex, bound to an evolutionarily conserved sequence on the Csx/Nkx2.5 promoter and displayed synergistic transcriptional activation. Furthermore, inhibition of HMGA2 in Xenopus embryos blocked cardiomyocyte differentiation … More and normal heart formation, implying an essential role for HMGA2 in cardiac development also in vivo.2) Current medical transplantation confronts major problems such as the shortage of donors and geographical restrictions that inhibit efficient utilization of finite donor organs within their storage lives. To overcome these issues, expanding organ preservation time has become a major concern. We investigated whether a strategy which best preserves organ grafts can be achieved by the use of a newly-developed refrigerating chamber, which is capable of establishing a supercooled and unfrozen state stably by generating an electrostatic field in its inside. When adult rat organs such as heart, liver, and kidneys were stored in the supercooled conditions, the levels of major biochemical markers leaked from the preserved organs were significantly lower than in the ordinary hypothermic storage. No apparent tissue damages were observed histologically after the supercooled preservation. Our results suggest that the use of this supercooling refrigerator improves organ preservation and may provide an innovative technique for human organ transplantation. Less