Department of Burns and Plastic Surgery, Children's hospital of Soochow University, Suzhou, China.
Suzhou Key Laboratory of Children's Structural Deformities, Suzhou, China.
Cell Death Dis. 2023 May 5;14(5):307. doi: 10.1038/s41419-023-05826-9.
The mitochondrial integrity and function in endothelial cells are essential for angiogenesis. TIMM44 (translocase of inner mitochondrial membrane 44) is essential for integrity and function of mitochondria. Here we explored the potential function and the possible mechanisms of TIMM44 in angiogenesis. In HUVECs, human retinal microvascular endothelial cells and hCMEC/D3 brain endothelial cells, silence of TIMM44 by targeted shRNA largely inhibited cell proliferation, migration and in vitro capillary tube formation. TIMM44 silencing disrupted mitochondrial functions in endothelial cells, causing mitochondrial protein input arrest, ATP reduction, ROS production, and mitochondrial depolarization, and leading to apoptosis activation. TIMM44 knockout, by Cas9-sgRNA strategy, also disrupted mitochondrial functions and inhibited endothelial cell proliferation, migration and in vitro capillary tube formation. Moreover, treatment with MB-10 ("MitoBloCK-10"), a TIMM44 blocker, similarly induced mitochondrial dysfunction and suppressed angiogenic activity in endothelial cells. Contrarily, ectopic overexpression of TIMM44 increased ATP contents and augmented endothelial cell proliferation, migration and in vitro capillary tube formation. In adult mouse retinas, endothelial knockdown of TIMM44, by intravitreous injection of endothelial specific TIMM44 shRNA adenovirus, inhibited retinal angiogenesis, causing vascular leakage, acellular capillary growth, and retinal ganglion cells degeneration. Significant oxidative stress was detected in TIMM44-silenced retinal tissues. Moreover, intravitreous injection of MB-10 similarly induced oxidative injury and inhibited retinal angiogenesis in vivo. Together, the mitochondrial protein TIMM44 is important for angiogenesis in vitro and in vivo, representing as a novel and promising therapeutic target of diseases with abnormal angiogenesis.
线粒体在血管生成中的完整性和功能对于血管生成至关重要。TIMM44（线粒体内膜转位酶 44）对于线粒体的完整性和功能是必需的。在这里，我们探讨了 TIMM44 在血管生成中的潜在功能和可能机制。在 HUVECs、人视网膜微血管内皮细胞和 hCMEC/D3 脑内皮细胞中，靶向 shRNA 沉默 TIMM44 可显著抑制细胞增殖、迁移和体外毛细血管形成。TIMM44 沉默破坏了内皮细胞中线粒体的功能，导致线粒体蛋白输入阻滞、ATP 减少、ROS 产生和线粒体去极化，并导致细胞凋亡激活。通过 Cas9-sgRNA 策略敲除 TIMM44 也破坏了线粒体功能并抑制了内皮细胞的增殖、迁移和体外毛细血管形成。此外，用 MB-10（“MitoBLOCK-10”）治疗，一种 TIMM44 阻断剂，也可诱导线粒体功能障碍并抑制内皮细胞的血管生成活性。相反，外源性过表达 TIMM44 可增加 ATP 含量并增强内皮细胞的增殖、迁移和体外毛细血管形成。在成年小鼠视网膜中，通过玻璃体内注射内皮特异性 TIMM44 shRNA 腺病毒来沉默 TIMM44，可抑制视网膜血管生成，导致血管渗漏、无细胞毛细血管生长和视网膜神经节细胞变性。在 TIMM44 沉默的视网膜组织中检测到明显的氧化应激。此外，玻璃体内注射 MB-10 也可在体内诱导氧化损伤并抑制视网膜血管生成。总之，线粒体蛋白 TIMM44 对于体外和体内的血管生成很重要，代表着一种具有异常血管生成的疾病的新型和有前途的治疗靶点。
