A positive loop formed by SOX11 and periostin upregulates TGF-β signals leading to skin fibrosis

Procyanidin C1 ameliorates aging-related skin fibrosis through targeting EGFR to inhibit TGFβ/SMAD pathway

BACKGROUND

Aging-related skin fibrosis (SF) is a complex condition with limited treatment options. Procyanidin C1 (PCC1), a natural polyphenolic compound with demonstrated senolytic activity, has emerged as a potential therapeutic agent for fibrotic disorders through its selective elimination of senescent cells. However, its therapeutic efficacy and mechanisms in aging-related SF remain unclear.

PURPOSE

This study aimed to investigate the mechanisms of PCC1 in aging-related SF.

RESULTS

In D-galactose-induced L929 cells, PCC1 treatment significantly attenuated the expression of both senescence-associated markers (IL-1β, P16, P21 and LMNB1) and fibrosis-related markers (α-SMA, LOXL2 and COL1). Network pharmacology and experimental validation (molecular docking, DARTS, CETSA, MST) identified EGFR as a primary target, with PCC1 directly binding to and inhibiting EGFR phosphorylation. Furthermore, PCC1 treatment effectively down-regulated TGFβ1 expression and suppressed SMAD2/3 phosphorylation in D-galactose-induced L929 cells. Notably, PCC1 blocked NSC228155-induced EGFR phosphorylation and inhibited ERK/MAPK, AKT/mTOR and TGFβ/SMAD pathway activation. In bleomycin-induced SF mice, PCC1 significantly attenuated epidermal hyperplasia, improved collagen structure, restored the collagen I/III ratio, and reduced EGFR phosphorylation along with TGFβ1 expression and SMAD2/3 phosphorylation.

CONCLUSION

This study elucidates that PCC1 exerts its anti-fibrotic effects through dual mechanisms: resistance to cellular senescence and modulation of fibroblast heterogeneity. By directly binding to EGFR and inhibiting its phosphorylation, PCC1 subsequently suppresses multiple downstream signaling cascades, ultimately ameliorating TGFβ/SMAD-mediated SF. These findings establish PCC1 as a promising therapeutic candidate for aging-related skin fibrosis, offering a novel approach through targeted EGFR inhibition and comprehensive pathway modulation.

SOX11 silence inhibits atherosclerosis progression in ApoE-deficient mice by alleviating endothelial dysfunction

SRY-Box Transcription Factor-11 (SOX11) is a transcriptional regulatory factor that plays a crucial role in inflammatory responses. However, its involvement in atherosclerosis (AS), a cardiovascular disease driven by endothelial cell inflammation, remains unknown. This study aims to elucidate the role of SOX11 in AS. The expression of SOX11 was found to be elevated in the aortic tissue of AS mice induced by feeding ApoE-deficient mice a high-fat diet. Knockdown of SOX11 using lentiviral-mediated SOX11-specific shRNA via tail vein injection resulted in a reduction in plaque area and lipid deposition within plaques at the aortic root. Furthermore, silencing SOX11 led to decreased expression of cell adhesion factors Intercellular Cell Adhesion Molecule-1 and Vascular Cell Adhesion Molecule-1, as well as reduced levels of inflammatory factors Interleukin (IL)-6, IL-1β, and chemokine Monocyte Chemotactic Protein-1. In the human umbilical vein endothelial cells (HUVECs) induced by Tumor Necrosis Factor (TNF)-α, increased inflammation was observed at the cellular level, along with enhanced monocyte adhesion. Infection of HUVECs with lentivirus carrying specific shRNA targeting SOX11 inhibited inflammatory response. Mechanistically, chromatin immunoprecipitation (ChIP)-PCR results revealed that SOX11 bound to the promoters of downstream target genes Tumor Necrosis Factor Receptor-Associated Factor-1 (TRAF1), Cluster of Differentiation (CD)40, and CD36, positively regulating their transcription. In conclusion, SOX11 plays a pivotal role in promoting endothelial cell inflammation. Suppression of SOX11 reduces endothelial cell inflammation by inhibiting the transcription of TRAF1, CD40, and CD36, thereby impeding the progression of atherosclerosis.

Activated hepatic stellate cell-derived Bmp-1 induces liver fibrosis via mediating hepatocyte epithelial-mesenchymal transition

Liver fibrosis is a reparative response to injury that arises from various etiologies, characterized by activation of hepatic stellate cells (HSCs). Periostin, a secreted matricellular protein, has been reported to participate in tissue development and regeneration. However, its involvement in liver fibrosis remains unknown. This study investigated the roles and mechanisms of Periostin in phenotypic transition of HSCs and relevant abnormal cellular crosstalk during liver fibrosis. The fate of hepatic stellate cells (HSCs) during liver fibrogenesis was investigated using single-cell and bulk RNA sequencing profiles, which revealed a significant proliferation of activated HSCs (aHSCs) in fibrotic livers of both humans and mice. αSMA-TK mice were used to demonstrate that depletion of proliferative aHSCs attenuates liver fibrosis induced by carbon tetrachloride and 3,5-diethoxycarbonyl-1,4-dihydrocollidine. Through integrating data from single-cell and bulk sequencing, Periostin was identified as a distinctive hallmark of proliferative aHSC subpopulation. Elevated levels of Periostin were detected in fibrotic livers of both humans and mice, primarily within aHSCs. However, hepatic Periostin levels were decreased along with depletion of proliferative aHSCs. Deficiency of Periostin led to reduced liver fibrosis and suppressed hepatocyte epithelial-mesenchymal transition (EMT). Periostin-overexpressing HSCs, exhibiting a proliferative aHSC phenotype, release bone morphogenetic protein-1 (Bmp-1), which activates EGFR signaling, inducing hepatocyte EMT and contributing to liver fibrosis. In conclusion, Periostin in aHSCs drives their acquisition of a proliferative phenotype and the release of Bmp-1. Proliferative aHSC subpopulation-derived Bmp-1 induces hepatocyte EMT via EGFR signaling, promoting liver fibrogenesis. Bmp-1 and Periostin should be potential therapeutic targets for liver fibrosis.