• Objective: To investigate the role of hepatocyte growth factor (HGF)-regulated adipose-derived mesenchymal stem cells (ADSCs) in promoting vocal fold repair through modulation of the TGF-_ signaling pathway.
• Methods: Rat ADSCs were isolated, cultured, and transduced with a lentiviral vector to overexpress HGF. Transfected ADSCs were sorted and validated by flow cytometry. To specifically silence Smad3 in fibroblasts, siRNA knockdown was conducted, followed by TGF-_ stimulation in vocal fold fibroblasts. The effects of ADSCs on fibroblast phenotype and extracellular matrix (ECM) components were assessed via immunofluorescence, while mRNA and protein levels were quantified using RT-qPCR and Western blot analysis. Confocal laser immunofluorescence further examined ECM protein localization relative to ADSCs with regulated expression.
• Results: Flow cytometry confirmed HGF overexpression in ADSCs after 28 days, showing a significant increase in HGF secretion. In the HGF-ADSCs group, there was a notable suppression of type I and III collagen and _-SMA expression, alongside an upregulation of hyaluronan synthase 1 (HAS1). Smad3 knockdown via siRNA in fibroblasts effectively mitigated fibrotic transformation, characterized by reduced type I/III collagen and _-SMA expression and increased HAS1 levels. The HGF-ADSCs group exhibited the most substantial modulation, including marked decreases in type I/III collagen and _-SMA secretion, with a concurrent increase in HAS1 (P = 0.000, 0.002, and 0.000, respectively). Additionally, TGF-_ mRNA levels were significantly downregulated (P = 0.001), while HGF mRNA expression was significantly upregulated (P = 0.000). Minimal changes were observed in ADSC groups. Upon adding exogenous TGF-_, both the normal and ADSCs groups showed elevated type I collagen and _-SMA levels (P = 0.000), whereas the HGF-ADSCs group maintained stable ECM and _-SMA expression levels.
• Conclusions: HGF appears to promote the transdifferentiation of ADSCs, with HGF-overexpressing ADSCs effectively suppressing the secretion of collagen I/III, enhancing HAS1 production, and downregulating the TGF-_/Smad3 signaling pathway. This mechanism may play a crucial role in alleviating pathological fibrosis in injured vocal folds.