成纤维生长因子受体1通过控制微小RNA let-7b表达调节内皮细胞线粒体生源的作用研究

Fibroblast growth factor receptor-1 is essential for regulation of mitochondrial biogenesis via control of microRNA let-Tb

目的探索成纤维生长因子受体l（fihrohlast growth factor receptor1，FGFRl）在调控内皮稳态时对上游分子N-乙酰基-丝氨酰-天冬氨酰-赖氨酰-脯氨酸（N-acetyl-seryl-aspartyl-lysyl-proline、AcSDKP）的影响和下游微小RNAlet-7（microRNA let-7、miR let-7）的诱导作用及与内皮细胞线粒体生源的关系，以期最终研究FGFR1在内皮稳态中的调控作用。方法下调FGF／FGFRl信号通路，蛋白质印迹（Western印迹．WB）法和细胞免疫荧光（Immunofluorescence staining）技术检测线粒体融合蛋白MFN2（mitofusin-2）、OPA1（optic atrophy protein1）和分裂蛋白DRP1（dynamin-related protein-1）的表达；应用线粒体染色（MitoTraker Green）检测线粒体的生成；运用实时荧光定量核酸扩增（Real-time Quantitative PCR、qPCR）检测技术检测microRNA let-7的表达。结果FGFRl通过诱导microRNA let-7b一5p的生成促进AcSDKP维持线粒体的生源；AcSDKP修复细胞因子复合物Triple（TGF-β2、IL-1β和TNF-α）所引起microRNA let-7b-5p表达抑制与线粒体的生成密切相关；抑制microRNA let-7b-5p的表达后，AcSDKP失去促进线粒体生成的作用：上调microRNA let-7b-5p的表达后，可修复内皮细胞中因FGF／FGFRl底物FRS2（fibroblast growth factor receptor substrate）沉默所致通路缺失所致的线粒体生成障碍。结论FGFRl通过上调microRNA let-7b-5p的表达，促进线粒体的生成，从而在内皮细胞的稳态中起着十分重要的作用。

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-scryl-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 , OPAl ） 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-Tb. In endothelial cells, the AcSDKP restored the triple ~[TGF-β2, interleukin （IL） -1β, tumor necrosis factor （TNF）-α]-suppressed microRNA let-7b-Sp 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-Sp mimic reversed the FRS2 siRNA-suppressed mitochondrial biogenesis in endothelial ceils. Conclusion These findings demonstrated that FGFR1 is critical for maintaining mitochondrial biogenesis through control of microRNA let-Tb-5p in endothelial ceils.