A new hypothesis: role of p53 inhibitory factors in cellular reprogramming

新假说：p53抑制因子在细胞重编程中的作用

• 批准号: 8632184
• 负责人: Kitai Kim
• 金额: $ 46.5万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-30 至 2019-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8632184
• 关键词: ATM promoter; Age; Aging; Apoptotic; Binding; Cell Line; Cell physiology; Cells; Centromere; Chromosomal Instability; Chronic; DNA Damage; Degenerative Disorder; Development; Ectopic Expression; Embryo; Epigenetic Process; Ethics; Fibroblasts; Genes; Genome Stability; Genomic Instability; Genomics; Goals; Human; Immune system; In Vitro; Individual; Lead; Legal patent; MAPK9 gene; Malignant Neoplasms; Molecular Abnormality; Mutation; Oncogenic; Oocytes; PLK1 gene; Pathway interactions; Patients; Phenotype; Phosphorylation; Pluripotent Stem Cells; Population; Regenerative Medicine; Replacement Therapy; Reporting; Research; Residual state; Role; Somatic Cell; Source; Stem cells; Systems Biology; Testing; Tissue Donors; Tissue Transplantation; Tissues; age effect; age related; aged; cell type; clinical application; comparative; embryonic stem cell; genome-wide; histone modification; improved; in vivo; induced pluripotent stem cell; innovation; insight; mouse model; normal aging; older patient; pluripotency; pressure; public health relevance; response; tissue regeneration; tool

Project Summary/Abstract Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)-generated by ectopic expression of four embryonic reprogramming genes in somatic cells-provide a source of patient-specific stem cells without the ethical limitations associated with embryonic stem cells (ESC). However, we and others have reported that iPSC are incompletely reprogrammed, and we found that the degree of reprogramming decreases with the age of the donor tissue. Our overall research goal is to improve the reprogramming of iPSC in order to produce high-quality patient-specific histocompatible tissues for transplantation. Because older patients are more likely to benefit from the clinical applications of iPSC, there is a significant need to comprehensively evaluate iPSC derived from older donor cells (A-iPSC) and identify additional pluripotent reprogramming factors that can reverse the negative impact of aging on A-iPSC reprogramming. Multiple reports have proposed that p53 is a negative regulator of somatic cell reprogramming, and that elimination of p53 increases iPSC reprogramming efficiency. However, basal p53 levels are elevated in ESC and iPSC compared with somatic cells, leading us to propose an innovative hypothesis-that iPSC reprogramming is incomplete due to insufficient inhibition of elevated p53 by p53 inhibitory factors. We further hypothesized that A-iPSC may be unable to activate these putative p53 inhibitory factors to overcome the elevated p53 during iPSC reprogramming. As a result, p53 cannot be completely restrained, and the residual p53 activity stimulates a constitutive DNA damage response that mimics what normally occurs only in response to a genotoxic insult. A chronic DNA damage response (via p53-dependent and -independent pathways) has also been observed during normal aging of somatic cells, and can lead to the complete loss of the DNA damage response during cancer development. We posited that epigenetic destruction of the entire DNA damage response would improve A-iPSC reprogramming and quality. In preliminary studies, we examined the function of two putative p53 inhibitory factors and used these factors to identify pluripotent regulatory factors that can correct the aging-related epigenetic landscape and improve the quality of A-iPSC. In this proposal, we will examine the function of these pluripotent regulatory factors by conducting a comprehensive comparative analysis of these iPSC types. In Aim 1, we will determine the mechanism by which the pluripotent regulatory factors reverse the aberrant DNA damage response and negative effects of aging on the A-iPSC phenotype. In Aim 2, we will determine the functional effects of the pluripotent regulatory factors by comparing the pluripotency and differentiation potential of each cell line in several in vitro and in vivo tests. Ultimately, our findings will provide critical insight into how we can improve the quality of patient-specific stem cells derived from aged patients for use in tissue regeneration and transplantation. Public Health Relevance Regenerative medicine using individual patent-derived iPSC has enomous potential to generate histocompatible transplantable tissue; this approach will particuarly benefit the aged population who is more likely to have degenerative disease. Ultimately, our findings and proposed research will provide critical insight into how we can improve the quality of patient-specific stem cells derived from aged patients for use in tissue regeneration and transplantation.

项目总结/文摘