Renault Marie-Ange, Roncalli Jérôme, Tongers Jörn, Misener Sol, Thorne Tina, Jujo Kentaro, Ito Aiko, Clarke Trevor, Fung Chris, Millay Meredith, Kamide Christine, Scarpelli Andrew, Klyachko Ekaterina, Losordo Douglas W
Feinberg Cardiovascular Research Institute, Northwestern University School of Medicine, 303 E Chicago Ave., Chicago, IL 60611, USA.
Circ Res. 2009 Oct 9;105(8):818-26. doi: 10.1161/CIRCRESAHA.109.206706. Epub 2009 Sep 3.
The Gli transcription factors are mediators of Hedgehog (Hh) signaling and have been shown to play critical roles during embryogenesis. Previously, we have demonstrated that the Hh pathway is reactivated by ischemia in adult mammals, and that this pathway can be stimulated for therapeutic benefit; however, the specific roles of the Gli transcription factors during ischemia-induced Hh signaling have not been elucidated.
To investigate the role of Gli3 in ischemic tissue repair.
Gli3-haploinsufficient (Gli3(+/-)) mice and their wild-type littermates were physiologically similar in the absence of ischemia; however, histological assessments of capillary density and echocardiographic measurements of left ventricular ejection fractions were reduced in Gli3(+/-) mice compared to wild-type mice after surgically induced myocardial infarction, and fibrosis was increased. Gli3-deficient mice also displayed reduced capillary density after induction of hindlimb ischemia and an impaired angiogenic response to vascular endothelial growth factor in the corneal angiogenesis model. In endothelial cells, adenovirus-mediated overexpression of Gli3 promoted migration (modified Boyden chamber), small interfering RNA-mediated downregulation of Gli3 delayed tube formation (Matrigel), and Western analyses identified increases in Akt phosphorylation, extracellular signal-regulated kinase (ERK)1/2 activation, and c-Fos expression; however, promoter-reporter assays indicated that Gli3 overexpression does not modulate Gli-dependent transcription. Furthermore, the induction of endothelial cell migration by Gli3 was dependent on Akt and ERK1/2 activation.
Collectively, these observations indicate that Gli3 contributes to vessel growth under both ischemic and nonischemic conditions and provide the first evidence that Gli3 regulates angiogenesis and endothelial cell activity in adult mammals.
Gli转录因子是刺猬信号通路（Hh）的介质，已被证明在胚胎发育过程中起关键作用。此前，我们已经证明，在成年哺乳动物中，Hh通路会因缺血而重新激活，并且该通路可以被刺激以获得治疗益处；然而，Gli转录因子在缺血诱导的Hh信号传导过程中的具体作用尚未阐明。
研究Gli3在缺血组织修复中的作用。
Gli3单倍体不足（Gli3(+/-)）小鼠及其野生型同窝小鼠在未发生缺血时生理状态相似；然而，与野生型小鼠相比，手术诱导心肌梗死后，Gli3(+/-)小鼠的毛细血管密度组织学评估和左心室射血分数的超声心动图测量值降低，纤维化增加。在诱导后肢缺血后，Gli3缺陷小鼠的毛细血管密度也降低，并且在角膜血管生成模型中对血管内皮生长因子的血管生成反应受损。在内皮细胞中，腺病毒介导的Gli3过表达促进迁移（改良的Boyden小室），小干扰RNA介导的Gli3下调延迟了管形成（基质胶），蛋白质免疫印迹分析确定Akt磷酸化、细胞外信号调节激酶（ERK）1/2激活和c-Fos表达增加；然而，启动子报告基因分析表明Gli3过表达不会调节Gli依赖的转录。此外，Gli3对内皮细胞迁移的诱导依赖于Akt和ERK1/2激活。
总的来说，这些观察结果表明Gli3在缺血和非缺血条件下均有助于血管生长，并提供了首个证据表明Gli3在成年哺乳动物中调节血管生成和内皮细胞活性。
