Li Wei, Xie Lin, Li Qiu-Ling, Xu Qiu-Yan, Lin Li-Rong, Liu Li-Li, Yang Tian-Ci
Center of Clinical Laboratory, Zhongshan Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, China.
Institute of Infectious Disease, School of Medicine, Xiamen University, Xiamen, China.
J Eur Acad Dermatol Venereol. 2023 Mar;37(3):558-572. doi: 10.1111/jdv.18728. Epub 2022 Nov 25.
Pathological angiogenesis is an important manifestation of syphilis, but the underlying mechanism of Treponema pallidum subspecies pallidum (T. pallidum)-induced angiogenesis is poorly understood.
The objective of this study is to investigate the role and related mechanism of the T. pallidum membrane protein Tp47 in angiogenesis.
The proangiogenic activity of recombinant T. pallidum membrane protein Tp47 in human umbilical vein endothelial cells (HUVECs) was assessed by tube formation assay, three-dimensional angiogenesis analysis and experiments with a zebrafish embryo model. The effects of mitochondrial ROS and NADPH oxidase on intracellular ROS induced by Tp47 were further investigated. Furthermore, the levels of autophagy-related proteins and autophagic flux were measured. Finally, the role of ROS-induced autophagy in angiogenesis was studied.
Tp47 promoted tubule formation and the formation of angiogenic sprouts in vitro. In addition, a significant increase in the number of subintestinal vessel branch points in zebrafish injected with Tp47 was observed using a zebrafish embryo model. Tp47 also significantly increased intracellular ROS levels in a dose-dependent manner. Tp47-induced tube formation and angiogenic sprout formation were effectively prevented by the ROS inhibitor NAC. In addition, Tp47 enhanced the production of mitochondrial ROS and expression of the NADPH oxidase-related proteins Nox2 and Nox4. The production of mitochondrial ROS and intracellular ROS was reduced by the NADPH oxidase inhibitors DPI and apocynin. Furthermore, Tp47 significantly increased expression of the autophagy-related proteins P62 and Beclin 1 and the LC3-II/LC3-I ratio and promoted an increase in autophagic flux, which could be effectively rescued by coincubation with the ROS inhibitor NAC. Further intervention with the autophagy inhibitor BafA1 significantly inhibited tube formation and angiogenic sprout formation.
Tp47-induced NADPH oxidase enhanced intracellular ROS production via mitochondrial ROS and promoted angiogenesis through autophagy mediated by ROS. These findings may contribute to our understanding of pathological angiogenesis in syphilis.
病理性血管生成是梅毒的重要表现，但苍白密螺旋体亚种（梅毒螺旋体）诱导血管生成的潜在机制尚不清楚。
本研究旨在探讨梅毒螺旋体膜蛋白Tp47在血管生成中的作用及相关机制。
通过管腔形成试验、三维血管生成分析和斑马鱼胚胎模型实验，评估重组梅毒螺旋体膜蛋白Tp47在人脐静脉内皮细胞（HUVECs）中的促血管生成活性。进一步研究线粒体活性氧（ROS）和NADPH氧化酶对Tp47诱导的细胞内ROS的影响。此外，检测自噬相关蛋白水平和自噬通量。最后，研究ROS诱导的自噬在血管生成中的作用。
Tp47促进体外管腔形成和血管生成芽的形成。此外，使用斑马鱼胚胎模型观察到，注射Tp47的斑马鱼肠下血管分支点数量显著增加。Tp47还以剂量依赖性方式显著提高细胞内ROS水平。ROS抑制剂NAC有效阻止了Tp47诱导的管腔形成和血管生成芽形成。此外，Tp47增强了线粒体ROS的产生以及NADPH氧化酶相关蛋白Nox2和Nox4的表达。NADPH氧化酶抑制剂二苯基碘鎓（DPI）和夹竹桃麻素降低了线粒体ROS和细胞内ROS的产生。此外，Tp47显著增加自噬相关蛋白P62和Beclin 1的表达以及LC3-II/LC3-I比值，并促进自噬通量增加，与ROS抑制剂NAC共同孵育可有效挽救这一现象。自噬抑制剂巴弗洛霉素A1（BafA1）的进一步干预显著抑制管腔形成和血管生成芽形成。
Tp47诱导的NADPH氧化酶通过线粒体ROS增强细胞内ROS产生，并通过ROS介导的自噬促进血管生成。这些发现可能有助于我们理解梅毒中的病理性血管生成。
