IGF2BP3 promotes early angiogenesis in pulmonary fibrosis by stabilizing HIF-1α

Angiogenesis plays a significant role in the progression of idiopathic pulmonary fibrosis (IPF). The RNA-binding protein IGF2BP3 is associated with fibrosis and angiogenesis, but its role in IPF angiogenesis remain unclear. Additionally, Tianlongjie (TL) has been confirmed to inhibit IPF progression, but the role of IGF2BP3 in this process also needs to be elucidated. A bleomycin (BLM)-induced pulmonary fibrosis rat model was established via intratracheal instillation of BLM, and an angiogenesis cell model was constructed by treating HPMVECs with VEGF165. HE staining was used to detect lung tissue injury. Masson staining, HYP content measurement, Western blot, and Immunohistochemistry assessed to evaluate fibrosis and angiogenesis progression. EdU staining was employed to detect cell proliferation. RIP-qPCR and dual-luciferase reporter assays were performed to examine the interaction between IGF2BP3 and HIF-1α. IGF2BP3 was abnormally highly expressed in pulmonary fibrosis. IGF2BP3 knockdown reduced the expression of HYP, COL-I, COL-III, α-SMA, CD31, CD34, and VEGFA in pulmonary fibrosis rat lung tissues, increased E-cadherin expression, and inhibited pulmonary fibrosis progression and microvascular formation in rats. In vitro, IGF2BP3 knockdown suppressed cell proliferation, migration and vascular endothelial cell angiogenesis. Mechanistically, IGF2BP3 may promote HIF-1α stability through m⁶A modification, and HIF-1α overexpression attenuated the inhibitory effect of IGF2BP3 knockdown on angiogenesis. Furthermore, TL treatment was associated with reduced fibrosis and lower IGF2BP3/HIF-1α expression. In conclusion, IGF2BP3 can promote pulmonary fibrosis-related angiogenesis by stabilizing HIF-1α expression, and TL inhibits IGF2BP3 and HIF-1α expression, angiogenesis and fibrosis progression in pulmonary fibrosis rats.