Aging is a major risk factor for cardiovascular disease. The aging heart shows progressive vascular dysfunction, hypertrophy, fibrosis, and electrical remodeling that collectively predispose to arrhythmias. We recently identified the vascular niche as an early hotspot of senescence and inflammatory activation, driving so-called inflammaging. Although senolytic treatments alleviate vascular aging, their non-specificity limits therapeutic applicability. Defining precise upstream regulators of endothelial senescence remains crucial for targeted intervention.
To identify such candidates, we screened cardiac microRNA (miR) profiles from young (3-month) versus aged (>18-month) mice. Among the most repressed transcripts, miR-145-5p emerged as a key regulator. RNA-scope in situ hybridization confirmed strong vascular and smooth mucle cell (SMC) localization and significant repression of miR145 in aged hearts (n = 3, p = 0.01). Notably, miR145 was also expressed by cardiac endothelial cells (ECs) and was equally diminished in aged ECs (n = 4, p = 0.0037).
Global deletion of the miR143/145 cluster induced profound cardiac arterial senescence (n = 4, p < 0.0001). To dissect cell-type–specific effects, we deleted miR143/145 selectively in vascular SMCs or ECs. SMC-specific deletion for 8 weeks did not affect cardiac remodeling or function and caused only mild vascular senescence, consistent with in vitro findings where anti-miR145 treatment induced limited SMC senescence and but reduced migration of SMC. Surprisingly, although the miR143/145 cluster is known for its enrichment in SMC, EC-specific deletion caused more severe effects including the significant induction of diastolic dysfunction, left atrial dilation, and enhanced endothelial senescence in vivo. Anti-miR145 treatment in human umbilical vein ECs impaired migration and proliferation, further supporting a profound effect of miR145 on ECs.
Single-nucleus RNA-seq of EC-specific miR143/145-deletion hearts (n = 3) revealed profound activation of senescence-associated genes, with a prominent upregulation of Serpine1, an anti-apoptotic and pro-senescent molecule. Silencing SERPINE1 in anti-miR145–treated ECs mitigated senescence, identifying Serpine1 as a downstream mediator of miR145 loss. Ligand–receptor analysis further suggested altered endothelial–neuronal and matrix interactions, including upregulation of Sema3a, collagens, and laminins. Functionally, EC-specific deletion reduced sympathetic innervation and increased vascular fibrosis.
Restoring miR145 in aged (18-month-old) mice via intravenous delivery of 1 nmol miR145 mimics elevated cardiac miR145 levels, improved diastolic function, and tended to reduce vascular senescence.
In conclusion, we identify endothelial miR145 as a critical upstream regulator of vascular senescence and cardiac dysfunction in aging. Unlike loss in SMCs, endothelial miR145 depletion drives profound functional decline, underscoring its distinct role in maintaining vascular integrity. Restoring endothelial miR145 levels ameliorates cardiac aging, highlighting its translational potential as a novel therapeutic target to preserve cardiovascular health in the elderly.
