Transcription Factor EB Drives Thrombospondin-1 Expression to DampenFocal-adhesion Signaling and Limit Post-infarction Cardiac Fibrosis

BACKGROUND: Cardiac fibroblasts (CFs) are essential for cardiac morphogenesis and homeostasis. We investigated whether transcription factor EB (TFEB) directly targeted and suppressed the activation of CFs, aiming to elucidate its underlying pathological mechanism from the perspectives of gene and cell therapy. METHODS: Following myocardial infarction (MI) induction, we performed transcriptome sequencing of CFs isolated from R26-LSL-TFEB+/+; Acta2-cre (n = 3) and R26-LSL-TFEB+/+ (n = 3) mice. Differential gene expression and functional enrichment analyses were conducted using R software. The binding between TFEB and Thrombospondin-1 (Thbs1) was validated by ChIP-qPCR assay. CFs were extracted from adult mice in the R26-LSL-TFEB+/+; Acta2-cre and R26-LSL-TFEB+/+ groups. Protein expressions of integrin, CD47, CD36, Thbs1, p-paxillin, vinculin, P-FAK, and α- SMA were detected by Western blot. Cell migration was assessed by the wound healing and Transwell assays. RESULTS: TFEB modulated the expression of a broad spectrum of RNAs associated with the transformation of CFs. Pathway analysis revealed significant enrichment in pathways related to extracellular matrix (ECM) receptor interaction and focal adhesion (FA). Notably, both mRNA and protein levels of Thbs1 were markedly elevated in TFEB-overexpressing CFs. Integrated computational prediction and chromatin immunoprecipitation assays identified that TFEB directly bound to the promoter region of Thbs1. This binding was associated with downstream modulation of its receptor network and a concomitant reduction in FA complex activation at the protein level. These findings positioned Thbs1 as a key transcriptional target through which TFEB regulated ECM-related signaling and cellular adhesion dynamics in CFs. DISCUSSION: The current findings showed that the modulation of Thbs1 and associated FA signaling was a mechanism through which TFEB overexpression exerted its anti-fibrotic effects on CFs. This highlighted the TFEB-Thbs1 axis as a potential novel target for developing therapeutic strategies to mitigate cardiac fibrosis. CONCLUSIONS: This study suggested that the protective effect of TFEB against MI injury was associated with the Thbs1/FA signaling pathway, providing a novel potential therapeutic target for cardiac fibrosis.