Annual Review & Research in Biology, ISSN: 2231-4776,Vol.: 3, Issue.: 4 (October-December)
Embedding the Future of Regenerative Medicine into the Open Epigenomic Landscape of Pluripotent Human Embryonic Stem Cells
Xuejun H. Parsons1,2* 1San Diego Regenerative Medicine Institute, San Diego, CA 92109, USA.
2Xcelthera, San Diego, CA 92109, USA.
Xuejun H. Parsons1,2*
1San Diego Regenerative Medicine Institute, San Diego, CA 92109, USA.
(1) Prof. Paula I. Moreira, Institute of Physiology, Faculty of Medicine, Center for Neuroscience and Cell Biology, University of Coimbra, Portugal.
(2) Prof. George Perry, Dean and Professor of Biology, University of Texas at San Antonio, USA.
Complete Peer review History: http://www.sciencedomain.org/review-history/1457
It has been recognized that pluripotent human embryonic stem cells (hESCs) must be transformed into fate-restricted derivatives before use for cell therapy. Realizing the therapeutic potential of pluripotent hESC derivatives demands a better understanding of how a pluripotent cell becomes progressively constrained in its fate options to the lineages of tissue or organ in need of repair. Discerning the intrinsic plasticity and regenerative potential of human stem cell populations reside in chromatin modifications that shape the respective epigenomes of their derivation routes. The broad potential of pluripotent hESCs is defined by an epigenome constituted of open conformation of chromatin mediated by a pattern of Oct-4 global distribution that corresponds genome-wide closely with those of active chromatin modifications. Dynamic alterations in chromatin states correlate with loss-of-Oct4-associated hESC differentiation. The epigenomic transition from pluripotence to restriction in lineage choices is characterized by genome-wide increases in histone H3K9 methylation that mediates global chromatin-silencing and somatic identity. Human stem cell derivatives retain more open epigenomic landscape, therefore, more developmental potential for scale-up regeneration, when derived from the hESCs in vitro than from the CNS tissue in vivo. Recent technology breakthrough enables direct conversion of pluripotent hESCs by small molecule induction into a large supply of lineage-specific neuronal cells or heart muscle cells with adequate capacity to regenerate neurons and contractile heart muscles for developing safe and effective stem cell therapies. Nuclear translocation of NAD-dependent histone deacetylase SIRT1 and global chromatin silencing lead to hESC cardiac fate determination, while silencing of pluripotence-associated hsa-miR-302 family and drastic up-regulation of neuroectodermal Hox miRNA hsa-miR-10 family lead to hESC neural fate determination. These recent studies place global chromatin dynamics as central to tracking the normal pluripotence and lineage progression of hESCs. Embedding lineage-specific genetic and epigenetic developmental programs into the open epigenomic landscape of pluripotent hESCs offers a new repository of human stem cell therapy derivatives for the future of regenerative medicine.
Human embryonic stem cell; stem cell; pluripotent; epigenome; chromatin; regenerative medicine; neurological disease; heart disease; cell therapy.
Full Article - PDF Page 323-349Review History Comments