TGF-β1 Induces Differentiation and Senescence in Cardiac Fibroblasts
Cardiac fibroblasts differentiate into myofibroblasts under TGF-β1 stimulation, acquiring senescent markers. Senolytic agents reduce viability of these cells.
Aging significantly increases the risk of cardiovascular disease through the accumulation of senescent cells within cardiac tissue. These cells exhibit irreversible cell cycle arrest and secrete a senescence-associated secretory phenotype (SASP) that drives inflammation and tissue remodeling, ultimately contributing to cardiac dysfunction. Cardiac fibroblasts serve as key regulators of cardiac repair but can differentiate into myofibroblasts in response to pathological stimuli such as mechanical stiffness and transforming growth factor-beta 1 (TGF-β1). While transient senescence may restrict fibrosis during acute injury, persistent senescence promotes chronic remodeling through sustained SASP activity.
The researchers investigated whether TGF-β1 simultaneously triggers both differentiation into myofibroblasts and induction of senescence in neonatal rat cardiac fibroblasts. They also examined whether the senotherapeutics Navitoclax and a combination of Dasatinib plus Quercetin modulate the viability of these differentiated cells. Cardiac fibroblasts were incubated in DMEM-F12 medium supplemented with 10% fetal bovine serum and treated with TGF-β1 at concentrations ranging from 10 to 46 ng/mL for seven days.
Protein analysis was conducted using Western blotting and immunocytochemistry, while cytokine profiling was performed via Milliplex assays. Results demonstrated that fibroblasts treated with TGF-β1 exhibited senescence markers including p15-p16, p21, increased SA-β-gal activity, and reduced Ki-67 and p-Rb expression. Differentiated myofibroblasts displayed enhanced secretion of IL-1β, IL-6, IL-5, and IL-10 alongside elevated collagen and VCAM-1 levels, indicating a pro-fibrotic and low-grade inflammatory phenotype.
Treatment with Navitoclax or the Dasatinib plus Quercetin combination decreased cell viability and reduced the proportion of SA-β-gal-positive cells. These findings suggest that TGF-β1 simultaneously promotes cardiac fibroblast differentiation into myofibroblasts and induces senescence, resulting in a sustained pro-fibrotic and inflammatory phenotype. Senotherapeutics treatment attenuates senescent myofibroblasts, supporting its potential as a therapeutic strategy to mitigate cardiac fibrosis in preclinical models.