Roles Of Drp1and Parkin In The Maintainance Of Pluripotency And Reprogramming

Mitochondria are organelles playing vital roles in a range of diverse cellular functions, from energy generation to cell differentiation and cell cycle and apoptosis regulation. Recently, mitochondria have been shown to exhibit different features and function in stem cells from differentiated cells. Drpl (Dynamin-related protein1) is involved in mitochondria fission and biogenesis in somatic cells. Mice lacking Drpl show embryonic lethal and have developmental abnormalities and die after embryonic day11.5-12.5. DRP1mislocalization also could promote neurodegeneration in vivo. Parkin, encoded by the PARK2gene, is a component of a multiprotein E3ubiquitin ligase complex which in turn is part of the ubiquitin-proteasome system that mediates the targeting of proteins for degradation including Drp1. Parkin appears to be involved in the maintenance of mitochondria, it may help trigger the destruction of mitochondria that are not working properly. The deletions or point mutation of the PARK2gene is identified as the most frequent cause of familial PD. How loss of function of the parkin protein leads to the disease is unclear. iPSCs retain the capability to self-renew indefinitely and to give rise to virtually any cell type of the body and thus hold great promise in medical research. An morphological restructuring to immature state of mitochondria has been observed during the process of cellular reprogramming. Understanding the mitochondrial properties of pluripotent cells, and how to modulate them, may thus help to shed light on the maintainace of pluripotency and possibly increase our knowledge on reprogramming and differentiation pathways. To investagate the function of Drp1and Parkin in the maintenance of pluripotency and reprogramming, we do the research. We show that Drpl band shift occurs in ES cells and iPS cells induced from fibroblasts, in association with mitochondrial morphogenesis. However, depletion of Drpl by shRNA does not abrogate mitochondria morphogenesis and induction of iPS cells from fibroblasts. Also, depletion of Drp1does not change mitochondria fission and function as shown by normal mitochondrial membrane potential, nor proliferation and pluripotency of ES cells. Nonetheless, Drpl knockdown negatively influences terminal differentiation of ES cells, particularly in the lineage of neurogenesis in vitro and in vivo, coincident with delayed reduction of Oct4and Nanog during mid-differentiation. Our data suggest that Drpl is redundant for mitochondria biogenesis in stem cell self-renewal but is required for neurogenesis likely by down-regulation of pluripotency-associated genes Nanog and Oct4. The induction of iPS cells makes it possible to derive induced pluripotent stem cells from donor individuals with particular characteristics. The induction of disease-specific patients bearing specific genetic mutations iPS cell lines is a promising approach for studying disease mechanisms, In the present study, we successfully generated the induced pluripotent stem (iPS) cells from somatic cells taken from WT and parkin knockout (KO) mouse model. We also examined the differentiation potential of generated iPS cell lines. Parkin-KO iPS cells are expected to be a powerful tool to study the pathogenesis of PD and provide a source for replacement therapies in this neurodegenerative disease.