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.
ABSTRACT
Objective To explore the change of microRNA let-7b in heat acclimatization/heat stroke rat models and its relation with HSP70,IL-6,TNF-α,TGF-3 and IL-12,and analyze its clinical significance.Methods 60 male rats with almost the same anal temperature,weight,and weeks' age were selected from Laboratory Animal Center in the Second Military Medical University.They were randomly divided into control,heat acclimatization,heat stroke groups averagely.Heat acclimatization/heat stroke rat models were built in hot climate simulated animal tank,blood was collected from cordis apex and serum was separated.Real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to test microRNA let-7b in serum,enzyme-linked immunosorbent reaction (ELISA) was to measure the protein level of HSP70,IL-6,TNF-α,TGF-β and IL-12 in serum.Kruskal-Wallis H test was used to analyze quantitative data in the three groups,Spearman rank correlation coefficient was used to reveal relation between two variables in heat stroke group.Results M values of miRNA let-7b in control,heat acclimatization,heat stroke groups were 0.99,1.04 and 1.93 separately,Q values were 0.30,0.25 and 0.44 (x2 =38.95,P＜0.001),separately,with statistical significance.The results of pairwise comparison showed no statistical difference in control and heat acclimatization (P＞0.05),but there were differences in control and heat stroke,heat acclimatization and heat stroke groups statistically (P＜0.05).Spearman correlation analysis showed that in heat stroke group,let-7b was positively related with HSP70,TNF-α and IL-6 (rs =0.579,0.498 and 0.609,P＜0.05) with statistical significance.Conclusion miR let-7b might involve in the pathology of heat stroke,it provided a potential biomarker for monitoring patients in high temperature and humidity clinically.