Abstract Body: Cardiac aging, a significant risk factor for cardiovascular diseases, occurs through the intricate interplay between cardiomyocytes (CM) and other non-CMs within the aging heart. Compared to the CMs, the non-CMs’ role in cardiac aging is understudied. In this study, we employed single-cell RNA-seq and scATAC-seq to profile the transcriptome and epigenome of non-CMs in young, middle-aged, and elderly mice. Our single-cell dual-omics analysis revealed aging response heterogeneity and its dynamics over time. Specifically, we observed that senescence-associated secretory phenotype (SASP), characterized by pro-inflammatory and fibrotic factors secretion, is prevalent in most non-CMs cell types in the aging murine heart, including fibroblasts, endothelial cells, and immune cells. Through change point detection analysis, we aim to identify the critical points in the aging trajectory—instances where SASP-related gene expression patterns shift significantly, reflecting the progression of senescence phenotypes. Utilizing gene regulatory network inferring tools, we will identify key driver genes orchestrating SASP activation in the heart, which regulate inflammatory and fibrotic pathways. We will employ a co-culture system to validate these findings to investigate the effects of silencing these driver genes in non-CMs and how these changes affect the cardiomyocyte phenotype. These results aim to establish SASP as a conserved hallmark of cardiac aging and highlight its molecular drivers as potential therapeutic targets. By integrating single-cell omics with experimental validation, our study seeks to provide novel insights into the mechanisms of cardiac aging and lay the groundwork for strategies to ameliorate age-related heart dysfunction.