Project description:Aging is a major risk factor for cardiovascular disease. Although the impact of aging has been extensively studied, little is known regarding the aging processes in cells of the heart. Here we analyzed the transcriptomes of hearts of 12-week-old and 18-month-old mice by single-nucleus RNA-sequencing. Among all cell types, aged fibroblasts showed most significant differential gene expression, increased RNA dynamics, and network entropy. Aged fibroblasts exhibited significantly changed expression patterns of inflammatory, extracellular matrix organization angiogenesis, and osteogenic genes. Functional analyses indicated deterioration of paracrine signatures between fibroblasts and endothelial cells in old hearts. Aged heart-derived fibroblasts had impaired endothelial cell angiogenesis and autophagy and augmented proinflammatory response. In particular, expression of Serpine1 and Serpine2 were significantly increased and secreted by old fibroblasts to exert antiangiogenic effects on endothelial cells, an effect that could be significantly prevented by using neutralizing antibodies. Moreover, we found an enlarged subpopulation of aged fibroblasts expressing osteoblast genes in the epicardial layer associated with increased calcification. Taken together this study provides system-wide insights and identifies molecular changes of aging cardiac fibroblasts, which may contribute to declined heart function.
Project description:To identify the gene regulatory network during heart aging, we used the RNA-seq to analyze the gene expression profile difference between adult mouse heart and aging mouse heart.
Project description:Sustained caloric restriction (CR) extends lifespan in animal models but the mechanism and primary tissue target(s) have not been identified. Gene expression changes with aging and CR were examined in both heart and subcutaneous white adipose tissue (WAT) of F344 male rats using Affymetrix® RAE 230 arrays and validated by qRT-PCR on 18 genes. In heart, age- associated changes but not CR-associated changes in old. In WAT, genes were identified where the aging change is suppressed by CR (candidate markers of healthy aging) and those affected by CR but not normal aging (candidate longevity assurance genes). 10-21% of age-associated genes were regulated in common between tissues. Gene set enrichment analysis (GSEA) revealed coordinate small magnitude changes in ribosomal, proteasomal, and mitochondrial genes with similarities between heart and WAT. Further analysis revealed PPARgamma as a potential upstream regulator of altered gene expression in old CR WAT. These results demonstrate a reduced mRNA response to CR with age in heart relative to WAT. In WAT, we identified candidate CR mimetic targets and candidate markers of healthy aging. These data suggest a role for subcutaneous WAT in the effects of CR and strengthen the role for PPAR signaling in aging and CR while indicating that the effects of CR in heart can occur independent of global changes in mRNA level. Keywords: Aging Caloric Restriction