Plasma exosomes are enriched in Hsp70 and modulated by stress and cortisol in rainbow trout
Plasma exosomes are enriched in Hsp70 and modulated by stress and cortisol in rainbow trout
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DOI：
10.1530/joe-16-0427
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发表时间：
2017-02-01
影响因子：
4
通讯作者：
Vijayan, Mathilakath M.
中科院分区：
文献类型：
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作者：
Faught, Erin;Henrickson, Lynsi;Vijayan, Mathilakath M.
外泌体是从细胞分泌的内体衍生的囊泡，含有一系列分子，包括蛋白质和核酸。最近的研究表明，循环中的外泌体可能会影响受体靶细胞的功能，但作用方式尚不清楚。在这里，我们测试了外泌体在鱼血浆中循环并且这些囊泡富含热休克蛋白 70 (Hsp70) 的假设。使用差速离心从虹鳟鱼（Oncorhynchus mykiss）血浆中分离出外泌体，并通过透射电子显微镜和外泌体标记乙酰胆碱酯酶证实了它们的存在。血浆外泌体富含 Hsp70，这种应激蛋白在鳟鱼血浆中短暂升高，以响应体内热休克。我们使用原代培养物中的鳟鱼肝细胞，测试了皮质醇（硬骨鱼中的主要皮质类固醇）的应激水平是否调节外泌体 Hsp70 含量。正如预期的那样，1 小时热休克（高于环境温度 +15 摄氏度）增加了肝细胞中 Hsp70 的表达，这导致 24 小时内外泌体中 Hsp7O 的富集程度更高。然而，皮质醇处理显着降低了未应激或热休克肝细胞释放的外泌体中 Hsp70 的表达。这种皮质醇介导的抑制并不是 Hsp7O 所特有的，因为用类固醇处理的肝细胞释放的外泌体中 β-肌动蛋白的表达也有所减少。我们的结果表明，循环中的 Hsp70 通过外泌体从靶组织中释放，并且它们的释放受到压力和皮质醇的调节。总的来说，我们提出了 Hsp70 的细胞外囊泡转运在生物体应激反应中的新作用。
Exosomes are endosomally derived vesicles that are secreted from cells and contain a suite of molecules, including proteins and nucleic acids. Recent studies suggest the possibility that exosomes in circulation may be affecting recipient target cell function, but the modes of action are unclear. Here, we tested the hypothesis that exosomes are in circulation in fish plasma and that these vesicles are enriched with heat shock protein 70 (Hsp70). Exosomes were isolated from rainbow trout (Oncorhynchus mykiss) plasma using differential centrifugation, and their presence was confirmed by transmission electron microscopy and the exosomal marker acetylcholinesterase. Plasma exosomes were enriched with Hsp70, and this stress protein was transiently elevated in trout plasma in response to a heat shock in vivo. Using trout hepatocytes in primary culture, we tested whether stress levels of cortisol, the principle corticosteroid in teleosts, regulates exosomal Hsp70 content. As expected, a 1-h heat shock (+15 degrees C above ambient) increased Hsp70 expression in hepatocytes, and this led to higher Hsp7O enrichment in exosomes over a 24-h period. However, cortisol treatment significantly reduced the expression of Hsp70 in exosomes released from either unstressed or heat shocked hepatocytes. This cortisol-mediated suppression was not specific to Hsp7O as beta-actin expression was also reduced in exosomes released from hepatocytes treated with the steroid. Our results suggest that circulating Hsp70 is released from target tissues via exosomes, and their release is modulated by stress and cortisol. Overall, we propose a novel role for extracellular vesicular transport of Hsp70 in the organismal stress response.