Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing 100853, China; Center for Cardiovascular Research and Alternative Medicine, Wyoming University, Laramie, WY 82071, USA.
Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing 100853, China.
Cell Signal. 2018 May;45:12-22. doi: 10.1016/j.cellsig.2018.01.020. Epub 2018 Feb 3.
Ripk3-mediated cellular apoptosis is a major contributor to the pathogenesis of myocardial ischemia reperfusion (IR) injury. However, the mechanisms by which Ripk3 influences microvascular homeostasis and endothelial apoptosis are not completely understood. In this study, loss of Ripk3 inhibited endothelial apoptosis, alleviated luminal swelling, maintained microvasculature patency, reduced the expression of adhesion molecules and limited the myocardial inflammatory response. In vitro, Ripk3 deficiency protected endothelial cells from apoptosis and migratory arrest induced by HR injury. Mechanistically, Ripk3 had the ability to migrate onto the endoplasmic reticulum (ER), leading to ER damage, as evidenced by increased IP3R and XO expression. The higher IP3R content was associated with cellular calcium overload, and increased XO expression was involved in cellular oxidative injury. Furthermore, IP3R-mediated calcium overload and XO-dependent oxidative damage were able to initiate cellular apoptosis. More importantly, IP3R and XO also caused F-actin degradation into G-actin via post-transcriptional modification of cofilin, impairing the formation of the filopodia and limiting the migratory response of endothelial cells. Altogether, our data confirmed that Ripk3 was involved in microvascular IR injury via regulation of IP3R-mediated calcium overload, XO-dependent oxidative damage and filopodia-related cellular migration, ultimately leading to endothelial apoptosis and migratory inhibition. These findings provide a potential target for treating cardiac microcirculatory IR injury.
Ripk3 介导的细胞凋亡是心肌缺血再灌注 (IR) 损伤发病机制的主要因素。然而，Ripk3 影响微血管稳态和内皮细胞凋亡的机制尚不完全清楚。在这项研究中，Ripk3 的缺失抑制了内皮细胞凋亡，减轻了管腔肿胀，维持了微血管通畅，减少了粘附分子的表达，并限制了心肌炎症反应。在体外，Ripk3 缺乏可保护内皮细胞免受 HR 损伤诱导的凋亡和迁移阻滞。在机制上，Ripk3 有能力迁移到内质网 (ER)，导致 ER 损伤，这表现为 IP3R 和 XO 表达增加。更高的 IP3R 含量与细胞内钙超载有关，而增加的 XO 表达则与细胞氧化损伤有关。此外，IP3R 介导的钙超载和 XO 依赖性氧化损伤能够引发细胞凋亡。更重要的是，IP3R 和 XO 还通过肌动蛋白丝切割蛋白 cofilin 的转录后修饰，将 F-肌动蛋白降解为 G-肌动蛋白，从而破坏丝状伪足的形成，限制内皮细胞的迁移反应。总之，我们的数据证实，Ripk3 通过调节 IP3R 介导的钙超载、XO 依赖性氧化损伤和与丝状伪足相关的细胞迁移，参与了微血管 IR 损伤，最终导致内皮细胞凋亡和迁移抑制。这些发现为治疗心脏微循环 IR 损伤提供了一个潜在的靶点。
