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Understanding the role of the stromal cell niche in intestinal stem cell aging

了解基质细胞生态位在肠道干细胞衰老中的作用

基本信息

批准号：
10591876
负责人：
Norihiro Goto
金额：
$ 13.67万
依托单位：
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-08-01 至 2025-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10591876
关键词：
Address Affect Aging Back Biology Cell Aging Cell Count Cells ChIP-seq Clinic Clinical Coculture Techniques Complex Dietary Intervention Engineering Enzymes Epigenetic Process Fibroblasts Fostering Gene Deletion Genes Goals Growth Health Homocysteine Hydrolase In Vitro Injury Intervention Intestines Knockout Mice LGR5 gene Ligands Lymphatic Endothelial Cells Measures Mediating Metabolism Methionine Methionine Metabolism Pathway Mus Natural regeneration Organoids Patients Population Regenerative capacity Rejuvenation Research Role Signal Transduction Sirolimus Source Stromal Cells Supporting Cell System Testing Time Training Translating Uncertainty Visualization age effect age related aged cell type conditional knockout dietary dietary restriction experimental study human old age (65+)improved in vitro testing in vivo in vivo evaluation insight intestinal epithelium mouse model novel pharmacologic programs promoter repaired single-cell RNA sequencing skills stem cell aging stem cell biology stem cell function stem cell homeostasis stem cell self renewal stem cells tool transcriptome sequencing

项目摘要

Project Summary Aging compromises the numbers/function of mammalian Lgr5+ intestinal stem cell (ISCs), which depend on niche factors produced by neighboring cell types like stromal cells. Although the necessity of these niche factors has been tested in vitro, many uncertainties remain regarding their in vivo sources and the impact of aging on them. To address these questions, we have focused on RSPO3, the dominant R-spondin in the mammalian intestine and Lgr5 ligand that drives ISC self-renewal. Using novel Rspo3-GFP mice, we have discovered that RSPO3 is expressed by two distinct populations in the intestinal stroma: RSPO3+GREM1+ fibroblasts (RG fibroblasts) and lymphatic endothelial cells (LECs). We have established heterotypic co-culture systems of RSPO3+ stromal cells with intestinal epithelial organoids, and have found that RG fibroblasts, more than LECs, support organoid growth. Importantly, the numbers/function of RG fibroblasts decline significantly in old mice. By RNA-seq, we have discovered that S-adenosyl-L-homocysteine hydrolase (Ahcy), a rate-limiting enzyme in methionine metabolism that hydrolyzes S-adenosyl homocysteine (SAH), is the most downregulated gene in aged mouse RG fibroblasts compared to their young counterparts. Furthermore, pharmacological inhibition of Ahcy recapitulates the age-related decline in the ability of RG fibroblasts to support ISCs, whereas short-term methionine restriction reverses the age-related decline of RG fibroblasts. We hypothesize that Ahcy loss and methionine accumulation in RG fibroblasts account for some of the age-related deficits of old ISCs that can be reversed by short-term dietary methionine restriction. In this proposal, we will test the hypothesis that RG fibroblasts are the dominant niche cells that foster ISCs in vivo (Aim 1); that loss of Ahcy leads to the age-related decline of RG fibroblasts through accumulation of methionine cycle intermediate metabolites (Aim 2); and that short-term dietary methionine restriction rejuvenates aged mouse RG fibroblasts to support ISCs and ISC-mediated regeneration (Aim 3). Through these aims, we will provide novel insights into how age-related changes in the ISC stromal niche contribute to ISC aging and how we can reverse it through modulating methionine metabolism. Identification of a new dietary intervention that may augment intestinal regeneration in old age will have important clinical implications. My goal is to discover novel insights into how aging influences stem cells with the long-term goal of translating these findings back to the clinic for the improvement of patient health. Because little is known about the aging and metabolism of stromal niche cells in ISC biology, the novel tools that I develop and the skill sets I acquire to assess metabolism of aging stromal niche cells during the K99 training period will permit me to establish a successful and independent research program as I transition to independence.

项目总结