Zhanjiang Institute of Clinical Medicine, Central People's Hospital of Zhanjiang, Guangdong Medical University Zhanjiang Central Hospital, Zhanjiang, 524045, People's Republic of China.
College of Pharmacy, China Pharmaceutical University, Nanjing, 211198, People's Republic of China.
Cell Mol Life Sci. 2023 Oct 19;80(11):330. doi: 10.1007/s00018-023-04980-9.
Dramatic alterations in epigenetic landscapes are known to impact genome accessibility and transcription. Extensive evidence demonstrates that senescent cells undergo significant changes in chromatin structure; however, the mechanisms underlying the crosstalk between epigenetic parameters and gene expression profiles have not been fully elucidated. In the present study, we delineate the genome-wide redistribution of accessible chromatin regions that lead to broad transcriptome effects during senescence. We report that distinct senescence-activated accessibility regions (SAAs) are always distributed in H3K27ac-occupied enhancer regions, where they are responsible for elevated flanking senescence-associated secretory phenotype (SASP) expression and aberrant cellular signaling relevant to SASP secretion. Mechanistically, a single transcription factor, TEAD4, moves away from H3K27ac-labled SAAs to allow for prominent chromatin accessibility reconstruction during senescence. The enhanced SAAs signal driven by TEAD4 suppression subsequently induces a robust increase in the expression of adjacent SASP genes and the secretion of downstream factors, which contribute to the progression of senescence. Our findings illustrate a dynamic landscape of chromatin accessibility following senescence entry, and further reveal an insightful function for TEAD4 in regulating the broad chromatin state that modulates the overall transcriptional program of SASP genes.
表观遗传景观的剧烈改变已知会影响基因组的可及性和转录。大量证据表明,衰老细胞的染色质结构会发生重大变化;然而,表观遗传参数与基因表达谱之间相互作用的机制尚未完全阐明。在本研究中,我们描绘了导致衰老过程中广泛转录组效应的全基因组可及染色质区域的重新分布。我们报告说,不同的衰老激活可及性区域 (SAA) 总是分布在 H3K27ac 占据的增强子区域,在这些区域,它们负责上调侧翼的衰老相关分泌表型 (SASP) 表达和与 SASP 分泌相关的异常细胞信号。从机制上讲,单个转录因子 TEAD4 从 H3K27ac 标记的 SAA 上移开,以允许衰老过程中明显的染色质可及性重构。由 TEAD4 抑制驱动的增强的 SAA 信号随后会导致相邻 SASP 基因的表达和下游因子的分泌显著增加,这有助于衰老的进展。我们的研究结果说明了衰老后染色质可及性的动态景观,并进一步揭示了 TEAD4 在调节广泛染色质状态方面的深入功能,这种状态调节了 SASP 基因的整体转录程序。