1 Center for Cardiology, Cardiology I, University Medical Center Mainz, Mainz, Germany.
2 Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK) e.V., Berlin, Germany.
Antioxid Redox Signal. 2019 Mar 1;30(7):927-944. doi: 10.1089/ars.2017.7169. Epub 2018 Feb 1.
Protein tyrosine phosphatase-1B (PTP1B) is a negative regulator of receptor tyrosine kinase signaling. In this study, we determined the importance of PTP1B expressed in endothelial cells for the vascular response to arterial injury in obesity.
Morphometric analysis of vascular lesions generated by 10% ferric chloride (FeCl) revealed that tamoxifen-inducible endothelial PTP1B deletion (Tie2.ER-Cre × PTP1B; End.PTP1B knockout, KO) significantly increased neointima formation, and reduced numbers of (endothelial lectin-positive) luminal cells in End.PTP1B-KO mice suggested impaired lesion re-endothelialization. Significantly higher numbers of proliferating cell nuclear antigen (PCNA)-positive proliferating cells as well as smooth muscle actin (SMA)-positive or vascular cell adhesion molecule-1 (VCAM1)-positive activated smooth muscle cells or vimentin-positive myofibroblasts were detected in neointimal lesions of End.PTP1B-KO mice, whereas F4/80-positive macrophage numbers did not differ. Activated receptor tyrosine kinase and transforming growth factor-beta (TGFβ) signaling and oxidative stress markers were also significantly more abundant in End.PTP1B-KO mouse lesions. Genetic knockdown or pharmacological inhibition of PTP1B in endothelial cells resulted in increased expression of caveolin-1 and oxidative stress, and distinct morphological changes, elevated numbers of senescence-associated β-galactosidase-positive cells, and increased expression of tumor suppressor protein 53 (p53) or the cell cycle inhibitor cyclin-dependent kinase inhibitor-2A (p16INK4A) suggested senescence, all of which could be attenuated by small interfering RNA (siRNA)-mediated downregulation of caveolin-1. In vitro, senescence could be prevented and impaired re-endothelialization restored by preincubation with the antioxidant Trolox.
Our results reveal a previously unknown role of PTP1B in endothelial cells and provide mechanistic insights how PTP1B deletion or inhibition may promote endothelial senescence.
Absence of PTP1B in endothelial cells impairs re-endothelialization, and the failure to induce smooth muscle cell quiescence or to protect from circulating growth factors may result in neointimal hyperplasia.
蛋白酪氨酸磷酸酶-1B（PTP1B）是受体酪氨酸激酶信号的负调节剂。在这项研究中，我们确定了肥胖症中动脉损伤血管反应中内皮细胞表达的 PTP1B 的重要性。
通过 10%三氯化铁（FeCl）生成的血管病变的形态计量分析表明，他莫昔芬诱导的内皮 PTP1B 缺失（Tie2.ER-Cre×PTP1B；End.PTP1B 敲除，KO）显著增加了新生内膜形成，并减少了 End.PTP1B-KO 小鼠中（内皮 lectin 阳性）管腔细胞的数量，表明损伤再内皮化受损。在 End.PTP1B-KO 小鼠的新生内膜病变中检测到更多的增殖细胞核抗原（PCNA）阳性增殖细胞以及平滑肌肌动蛋白（SMA）阳性或血管细胞粘附分子-1（VCAM1）阳性激活的平滑肌细胞或波形蛋白阳性的肌成纤维细胞，而 F4/80 阳性巨噬细胞数量无差异。活性受体酪氨酸激酶和转化生长因子-β（TGFβ）信号和氧化应激标志物在 End.PTP1B-KO 小鼠病变中也明显更丰富。内皮细胞中 PTP1B 的基因敲低或药理学抑制导致 caveolin-1 和氧化应激的表达增加，以及明显的形态变化、衰老相关β-半乳糖苷酶阳性细胞数量增加，以及肿瘤抑制蛋白 53（p53）或细胞周期抑制剂细胞周期蛋白依赖性激酶抑制剂-2A（p16INK4A）的表达增加，表明衰老，所有这些都可以通过小干扰 RNA（siRNA）介导的 caveolin-1 下调来减弱。在体外，通过预孵育抗氧化剂 Trolox 可以预防衰老并恢复受损的再内皮化。
我们的结果揭示了 PTP1B 在内皮细胞中的一个先前未知的作用，并提供了关于 PTP1B 缺失或抑制如何促进内皮细胞衰老的机制见解。
内皮细胞中缺乏 PTP1B 会损害再内皮化，并且未能诱导平滑肌细胞静止或免受循环生长因子的保护可能导致新生内膜增生。
