Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5508862 | Biochimica et Biophysica Acta (BBA) - Molecular Cell Research | 2017 | 38 Pages |
Abstract
The importance of macroautophagy (hereafter referred to as autophagy) in vascular endothelial cell (VEC) biology and dysfunction is increasingly recognized, but the molecular mechanisms of autophagy in VECs in the presence of serum are still poorly understood. Previously, we identified pterostilbene as a potent autophagy inducer of VECs in the presence of serum. In this study, we used pterostilbene as a tool to induce VEC autophagy and identified the differentially expressed genes using high-throughput DAN microarray. The small GTPase Ras-related protein in brain 13 (Rab13) was found to be the most significantly up-regulated gene in pterostilbene-treated human umbilical VECs (HUVECs). Knockdown of Rab13 blocked pterostilbene-induced mTOR inhibition and autophagy, whereas overexpression of the GTP-containing active form of Rab13 induced mTOR inhibition and autophagy in HUVECs. Using a combination of immunofluorescence and co-immunoprecipitation (co-IP) assays, we demonstrated that pterostilbene or up-regulation of the active form of Rab13 promoted the interaction between Rab13 and growth factor receptor-bound protein 2 (Grb2). Knockdown of Grb2 suppressed pterostilbene or up-regulation of the active form of Rab13-induced autophagy. Further mechanistic studies revealed that Rab13 activated the downstream AMP-activated protein kinase (AMPK) and blocked mammalian target of rapamycin (mTOR) signaling by its functional interaction with Grb2 to regulate autophagy in HUVECs. Our study firmly establishes Rab13 as a novel regulator of autophagy in VECs under nutrient-enriched conditions.
Keywords
70-kDa ribosomal protein S6 kinase4E-BP1MacroautophagyPBS-TFGF-2AMPKMEFsp70S6KHUVECqRT-PCRVECsRT-PCRHRPmTORAVOsPVDFRab13GRB2TMSAMP-activated protein kinaseAcridine orangeAcidic vesicular organellesTemImmunoprecipitationpolyvinylidene difluoridevascular endothelial cellHuman umbilical vein endothelial cellVascular endothelial cellsfibroblast growth factor 2mouse embryonic fibroblastsTransmission electron microscopywild-typeNitric oxidemammalian target of rapamycinhemagglutininquantitative real-time PCRPterostilbeneHorseradish peroxidasegrowth factor receptor-bound protein 2
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Authors
Lu Zhang, Fang Dai, LiuQing Cui, Bo Zhou, YuQi Guo,