CaMKIV 在脓毒症期间调节线粒体动力学。

CaMKIV regulates mitochondrial dynamics during sepsis.

机构信息

Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.

Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Department of Emergency, Union Hospital, Tongji Medical College, Hua Zhong University of Science and Technology, Wuhan, China.

出版信息

Cell Calcium. 2020 Dec;92:102286. doi: 10.1016/j.ceca.2020.102286. Epub 2020 Sep 5.

Abstract

Sepsis and shock states impose mitochondrial stress, and in response, adaptive mechanisms such as fission, fusion and mitophagy are induced to eliminate damaged portions of or entire dysfunctional mitochondria. The mechanisms underlying these events are being elucidated; yet a direct link between loss of mitochondrial membrane potential ΔΨm and the initiation of fission, fusion and mitophagy remains to be well characterized. The direct association between the magnitude of the ΔΨm and the capacity for mitochondria to buffer Ca renders Ca uniquely suited as the signal engaging these mechanisms in circumstances of mitochondrial stress that lower the ΔΨm. Herein, we show that the calcium/calmodulin-dependent protein kinase (CaMK) IV mediates an adaptive slowing in oxidative respiration that minimizes oxidative stress in the kidneys of mice subjected to either cecal ligation and puncture (CLP) sepsis or endotoxemia. CaMKIV shifts the balance towards mitochondrial fission and away from fusion by 1) directly phosphorylating an activating Serine616 on the fission protein DRP1 and 2) reducing the expression of the fusion proteins Mfn1/2 and OPA-1. CaMKIV, through its function as a direct PINK1 kinase and regulator of Parkin expression, also enables mitophagy. These data support that CaMKIV serves as a keystone linking mitochondrial stress with the adaptive mechanisms of mitochondrial fission, fusion and mitophagy that mitigate oxidative stress in the kidneys of mice responding to sepsis.

摘要

脓毒症和休克状态会对线粒体造成应激,作为应对,分裂、融合和自噬等适应性机制被激活,以消除受损或功能失调的线粒体部分或整个细胞器。这些事件的发生机制正在被阐明;然而,线粒体膜电位(ΔΨm)的丧失与分裂、融合和自噬的启动之间的直接联系仍有待充分描述。线粒体中 ΔΨm 的幅度与线粒体缓冲 Ca 的能力之间的直接关联使得 Ca2+ 成为信号分子,在降低 ΔΨm 的线粒体应激情况下,Ca2+ 可以激活这些机制。本文中,我们发现钙/钙调蛋白依赖性蛋白激酶(CaMK)IV 介导了氧化呼吸的适应性减缓,从而使接受盲肠结扎穿孔(CLP)脓毒症或内毒素血症的小鼠肾脏中的氧化应激最小化。CaMKIV 通过以下两种方式改变线粒体分裂和融合之间的平衡:1)直接磷酸化分裂蛋白 DRP1 上的激活性丝氨酸 616;2)减少融合蛋白 Mfn1/2 和 OPA-1 的表达。CaMKIV 通过其作为 PINK1 激酶和 Parkin 表达的调节剂的功能,还能促进自噬。这些数据表明,CaMKIV 作为一个关键节点,将线粒体应激与线粒体分裂、融合和自噬的适应性机制联系起来,从而减轻了对脓毒症反应的小鼠肾脏中的氧化应激。

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