Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
Department of Hospital Infection Management, Wuhan Children’s Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
Aging (Albany NY). 2020 Dec 3;13(1):957-972. doi: 10.18632/aging.202211.
Bnip3, which is regulated by Hif-1 in cells under oxygen deprivation, is a death related protein associated with autophagy and apoptosis. Hif-1 was reported to regulate autophagy to activate hepatic stellate cells (HSCs), while the specific molecular mechanism is vague. The possible mechanism of Hif-1 regulating autophagy of HSCs via Bnip3 was explored in this study. Bnip3 was detected in fibrotic liver tissues from humans and mice. Hif-1 was inhibited by chemical inhibitor and Bnip3 was detected in activated HSCs. The co-localization of Bnip3 and LC3B was captured by confocal microscopy and autophagic flow was assessed in siRNA transfected cells. Bnip3 interacted proteins were screened with mass spectrometry. The interaction of Bnip3 and vimentin was detected with co-immunoprecipitation and confocal microscopy. The results showed that Bnip3 was increased in fibrotic liver tissues and activated HSCs. Hif-1 inhibition suppressed Bnip3 expression in activated HSCs. Bnip3 was partially co-localized with autophagosomes and Bnip3 inhibition suppessed autophagy in activated HSCs. Bnip3 interacted with vimentin and Bnip3 expression was inhibited as vimentin was inhibited in activated HSCs. Conclusively, this study indicated that Bnip3 promoted autophagy and activation of HSCs, via interacting with vimentin, an intermediate filament protein with highly abundant expression in HSCs.
Bnip3 是一种在缺氧细胞中受 Hif-1 调节的与自噬和凋亡相关的死亡相关蛋白。有报道称，Hif-1 通过调节自噬来激活肝星状细胞（HSCs），但其具体的分子机制尚不清楚。本研究旨在探讨 Hif-1 是否通过 Bnip3 调节 HSCs 的自噬。在人类和小鼠的纤维化肝组织中检测到 Bnip3。用化学抑制剂抑制 Hif-1，检测激活的 HSCs 中的 Bnip3。用共聚焦显微镜捕获 Bnip3 和 LC3B 的共定位，并在 siRNA 转染的细胞中评估自噬流。用质谱筛选 Bnip3 的相互作用蛋白。用共免疫沉淀和共聚焦显微镜检测 Bnip3 与波形蛋白的相互作用。结果表明，Bnip3 在纤维化肝组织和激活的 HSCs 中增加。Hif-1 抑制抑制了激活的 HSCs 中 Bnip3 的表达。Bnip3 部分与自噬体共定位，Bnip3 抑制抑制了激活的 HSCs 中的自噬。Bnip3 与波形蛋白相互作用，且当激活的 HSCs 中波形蛋白被抑制时，Bnip3 的表达也被抑制。综上，本研究表明，Bnip3 通过与波形蛋白相互作用，促进了自噬和 HSCs 的激活，而波形蛋白是 HSCs 中高丰度表达的中间丝蛋白。
