Nonylphenol induces myocardial fibrosis by activating the TGF- β1/LIMK1 signaling pathway

Abstract Objective: The objective was to explore whether perinatal nonylphenol (NP) exposure leads to myocardial fibrosis during adulthood in male rats and to determine the action of the TGF-β1/limk1 signaling pathway in np-induced fibrosis in cardiac fibroblasts (CFs). Methods and Results: The histopathological results showed increased collagen deposition and altered fiber arrangement in the NP and model groups compared with the blank group. The systolic and diastolic functions were impaired. Western blot and qRT-PCR analysis showed that the central myofibrosis-related proteins (collagen I, collagen III, MMP2, MMP9, TGF-β1, α-SMA, IL-1β, and TGF-β1) and genes (Collagen I, Collagen III, TGF-β1, and α-SMA mRNA) were upregulated in the NP and model groups compared with the blank group. The mRNA-seq analysis indicated differential expression of TGF-β1 signaling pathway. In vitro, fibrosis-related protein and gene expression was increased in CFs under recombinant human TGF-β1 and NP stimulation, which was consistent with the results of animal experiments. Mechanistically, immunofluorescence (IF) and Western blot analysis showed that NP exposure activated the TGF-β1/LIMK1 signaling pathway. The mechanism of TGF-β1/LIMK1 signaling pathway in NP-induced CFs was further validated. LIMK1 inhibitor (BMS-5) modulated the TGF-β1/LIMK1 signaling pathway and then suppressed the NP-induced increase in fibrosis-related protein expression in CFs. These results suggest that the TGF-β1/LIMK1 signaling pathway is involved in NP-induced fibrosis. Conclusion: Our results provide the first evidence suggesting that perinatal NP exposure causes myocardial fibrosis in growing male rat pups and reveal the molecular mechanism and functional role of the TGF-β1/LIMK1 signaling pathway in this process.