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自噬溶酶体和半胱天冬酶-3 控制免疫原性凋亡外泌体的生成和释放。

Autolysosomes and caspase-3 control the biogenesis and release of immunogenic apoptotic exosomes.

机构信息

Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM), Université de Montréal, Montréal, QC, Canada.

Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada.

出版信息

Cell Death Dis. 2022 Feb 11;13(2):145. doi: 10.1038/s41419-022-04591-5.

Abstract

Apoptotic exosome-like vesicles (ApoExos) are a novel type of extracellular vesicle that contribute to the propagation of inflammation at sites of vascular injury when released by dying cells. ApoExos are characterized by the presence of the C-terminal perlecan LG3 fragment and 20S proteasome, and they are produced downstream of caspase-3 activation. In the present study, we assessed the relative roles of autophagy and caspase-3-mediated pathways in controlling the biogenesis and secretion of immunogenic ApoExos. Using electron microscopy and confocal immunofluorescence microscopy in serum-starved endothelial cells, we identified large autolysosomes resulting from the fusion of lysosomes, multivesicular bodies, and autophagosomes as a site of ApoExo biogenesis. Inhibition of autophagy with ATG7 siRNA or biochemical inhibitors (wortmannin and bafilomycin) coupled with proteomics analysis showed that autophagy regulated the processing of perlecan into LG3 and its loading onto ApoExos but was dispensable for ApoExo biogenesis. Caspase-3 activation was identified using caspase-3-deficient endothelial cells or caspase inhibitors as a pivotal regulator of fusion events between autolysosomes and the cell membrane, therefore regulating the release of immunogenic ApoExos. Collectively, these findings identified autolysosomes as a site of ApoExo biogenesis and caspase-3 as a crucial regulator of autolysosome cell membrane interactions involved in the secretion of immunogenic ApoExos.

摘要

凋亡外泌体样小泡(ApoExos)是一种新型的细胞外囊泡,当细胞死亡时会释放 ApoExos,从而促进血管损伤部位炎症的传播。ApoExos 的特征是存在 C 末端的硫酸乙酰肝素蛋白聚糖 LG3 片段和 20S 蛋白酶体,并且它们是在 caspase-3 激活的下游产生的。在本研究中,我们评估了自噬和 caspase-3 介导的途径在控制免疫原性 ApoExos 的生物发生和分泌中的相对作用。使用电子显微镜和血清饥饿的内皮细胞共聚焦免疫荧光显微镜,我们鉴定出大自噬体,它是由溶酶体、多泡体和自噬体融合产生的,是 ApoExo 生物发生的部位。用 ATG7 siRNA 或生化抑制剂(wortmannin 和 bafilomycin)抑制自噬,并结合蛋白质组学分析表明,自噬调节了硫酸乙酰肝素蛋白聚糖向 LG3 的加工及其加载到 ApoExos 上,但对 ApoExo 的生物发生是可有可无的。使用 caspase-3 缺陷型内皮细胞或 caspase 抑制剂鉴定 caspase-3 激活是自噬体与细胞膜融合事件的关键调节因子,因此调节免疫原性 ApoExos 的释放。总之,这些发现确定了自噬体是 ApoExo 生物发生的部位,caspase-3 是参与免疫原性 ApoExo 分泌的自噬体与细胞膜相互作用的关键调节因子。

https://cdn.ncbi.nlm.nih.gov/pmc/blobs/08f0/8837616/d0cf01764a0a/41419_2022_4591_Fig1_HTML.jpg

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