ABSTRACT
Objective@#To investigate the role of fibroblast growth factor receptor(FGFR) 1 in endothelial to-mesenchymal transition(EndMT) and epithelial-to-mesenchymal transition(EMT), and to find out a new strategy to study the vascular endothelial function of diabetic renal fibrosis.@*Methods@#Culture media from FRS2 knockdown HMVECs was transferred to HK-2 cells. Western blot and immunofluorescence staining were used to measure EMT markers and key moleculars of transforming growth factor(TGFβ).@*Results@#It was found that the medium from FRS2 siRNA-transfected HMVECs reduced E-cadherin protein levels, increased EMT markers levels, and activated TGFβ signal pathway in HK-2 cells.@*Conclusion@#Endothelial FGFR1 deficiency-induced EndMT leads to EMT in neighboring cells in a manner dependent on TGFβ1 signaling. Endothelial cell FGFR1 is an important molecule for maintaining endothelial homeostasis and epithelial homeostasis, and seems to be a key target for anti-diabetic renal fibrosis.
ABSTRACT
Objective To explore the role of fibroblast growth factor receptor ( FGFR ) 1 in endothelial homeostasis via an induction of microRNA let-7s, with effects on AcSDKP(N-acetyl-seryl-aspartyl-lysyl-proline) and associated mitochondrial biogenesis. Methods Blocking FGFR1 signaling pathway, Western blot and immunofluorescence staining were used to measure mitochondrial fusion ( mitofusin-2, MFN2;optic atrophy protein 1, OPA1 ) and fission ( dynamin-related protein-1, DRP1 ) proteins and mitochondrial biogenesis by MitoTraker Green. Also real-time quantitative PCR(qPCR) was performed to test microRNA let-7' expression. Results FGFR1 signaling pathway was critical for AcSDKP maintaining mitochondrial biogenesis through induction of microRNA let-7b. In endothelial cells, the AcSDKP restored the triple[TGF-β2, interleukin (IL)-1β, tumor necrosis factor (TNF)-α]-suppressed microRNA let-7b-5p expression and associated with mitochondrial biogenesis. Such effect of AcSDKP was lost in either fibroblast growth factor receptor substrate 2 (FRS2) siRNA or neutralizing FGFR1 treated-cells. Similarly, AcSDKP lost its effect on mitochondrial biogenesis in microRNA let-7b-5p inhibitor-treated-cells. In addition, microRNA let-7b-5p mimic reversed the FRS2 siRNA-suppressed mitochondrial biogenesis in endothelial cells. Conclusion These findings demonstrated that FGFR1 is critical for maintaining mitochondrial biogenesis through control of microRNA let-7b-5p in endothelial cells.