Heat shock protein B1 is a key mediator of prolactin-induced beta-cell cytoprotection against oxidative stress.
Heat shock protein B1 is a key mediator of prolactin-induced beta-cell cytoprotection against oxidative stress.
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DOI：
10.1016/j.freeradbiomed.2019.01.023
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发表时间：
2019-04
影响因子：
7.4
通讯作者：
L. F. Terra;R. Wailemann;A. F. dos Santos;V. M. Gomes;R. Silva;A. Laporte;F. Meotti;W. Terra;G. Palmisano;S. Lortz;L. Labriola
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作者：
L. F. Terra;R. Wailemann;A. F. dos Santos;V. M. Gomes;R. Silva;A. Laporte;F. Meotti;W. Terra;G. Palmisano;S. Lortz;L. Labriola
体外维持胰岛细胞的活性，虽然具有挑战性，但似乎是改善胰岛移植结果的策略。我们已经表明，催乳素（PRL）导致β细胞对细胞凋亡的细胞保护，热休克蛋白B1（HSPB 1）介导的效果。由于HSPB 1在β细胞中的作用尚不清楚，并且由于激素在其他组织中显示的所有副作用，所使用的激素浓度与临床应用不相容，因此我们探索了HSPB 1介导β细胞细胞保护的分子机制。PRL处理的细胞呈现出与HSPB 1共沉淀的几种蛋白质的富集。值得注意的是氧化应激抗性，蛋白质降解和碳水化合物代谢相关的proteins.Wild型，HSPB 1沉默或过表达MIN 6细胞暴露于甲萘醌和过氧化氢，并分析了几个氧化应激参数。HSPB 1基因敲低使细胞对氧化应激更敏感，导致抗氧化能力降低，而催乳素诱导HSPB 1介导的细胞保护作用对抗氧化应激。然而，HSPB 1过表达导致相反的效果。PRL处理、HSPB 1沉默或过表达不改变抗氧化酶的表达或活性，也不导致总谷胱甘肽水平或G6 PD表达的调节。然而，HSPB 1水平与GSH/GSSG比率、G6 PD活性和NADPH/NADP+比率的调节有关。这些结果与PRL诱导的HSPB 1相互作用蛋白的富集与抗氧化应激保护有关。最后，我们的研究结果概述了进一步研究HSPB 1对β细胞活力的重要性的必要性，因为这可能会导致通过内源性保护途径的上调来减轻β细胞死亡。
Maintaining islet cell viabilityin vitro, although challenging, appears to be a strategy for improving the outcome of pancreatic islet transplantation. We have shown that prolactin (PRL) leads to beta-cell cytoprotection against apoptosis, an effect mediated by heat shock protein B1 (HSPB1). Since the role of HSPB1 in beta-cells is still unclear and the hormone concentration used is not compatible with clinical applications because of all the side effects displayed by the hormone in other tissues, we explored the molecular mechanisms by which HSPB1 mediates beta-cell cytoprotection.Lysates from PRL- and/or cytokine-treated MIN6 beta-cells were subjected to HSPB1 immunoprecipitation followed by identification through mass spectrometry. PRL-treated cells presented an enrichment of several proteins co-precipitating with HSPB1. Of note were oxidative stress resistance-, protein degradation- and carbohydrate metabolism-related proteins.Wild type, HSPB1 silenced or overexpressing MIN6 cells were exposed to menadione and hydrogen peroxide and analysed for several oxidative stress parameters. HSPB1 knockdown rendered cells more sensitive to oxidative stress and led to a reduced antioxidant capacity, while prolactin induced an HSPB1-mediated cytoprotection against oxidative stress. HSPB1 overexpression, however, led to opposite effects. PRL treatment, HSPB1 silencing or overexpression did not change the expression nor activities of antioxidant enzymes, it also did not lead to a modulation of total glutathione levels nor G6PD expression. However, HSPB1 levels are related to a modulation of GSH/GSSG ratio, G6PD activity and NADPH/NADP+ratio.We have shown that HSPB1 is important for pro-survival effects against oxidative stress-induced beta-cell death. These results are in accordance with PRL-induced enrichment of HSPB1-interacting proteins related to protection against oxidative stress. Finally, our results outline the need of further studies investigating the importance of HSPB1 for beta-cell viability, since this could lead to the mitigation of beta-cell death through the up-regulation of an endogenous protective pathway.