Treponema pallidum induces the activation of endothelial cells via macrophage-derived exosomes
- 46 Downloads
Recent studies have shown that exosomes play a role in pathogenesis and in the treatment of inflammatory diseases and tumours. We explored the effects of Treponema pallidum-induced macrophage-derived exosomes on vascular endothelial cells to determine whether they are involved in the pathogenesis of syphilis. A syphilis infection model was established using rabbits to harvest T. pallidum at the peak of proliferation. Exosomes derived from macrophages were extracted using commercial kits and characterized by transmission electron microscopy, western blot assays, and nanoparticle tracking analysis. Secreted cytokine levels and the adhesion and permeability of human umbilical vein endothelial cells were evaluated in a co-culture model using the extracted exosomes. The results of this study revealed that exosomes derived from T. pallidum-infected macrophages enhanced cell adhesion and permeability. The levels of the secreted cytokines, including ICAM-1, VCAM-1, VEGF, and IL-8 were higher in the experimental group than in the control group. Our findings suggest that exosomes derived from T. pallidum-infected macrophages affect the cell adhesion and permeability of vascular endothelial cells. These changes may play important roles in syphilis pathogenesis. This study is the first to reveal the effects of exosomes derived from T. pallidum-infected macrophages on the adhesion, permeability, and secreted cytokines of human umbilical vein endothelial cells.
KeywordsSyphilis Treponema pallidum Macrophage Exosome Endothelial cells
We thank Professor Tianci Yang (Zhongshan Hospital, Medical College of Xiamen University) for supplying us T. pallidum (Nichols strain) and the Nanjing Military Region CDC for their assistance in the animal experiment. We acknowledge Guo-Jun Liang and Zhi-Ju Zheng for their support and assistance. We also thank Xiang-Dong Gong and Fang-Zhi Du for their assistance with data analysis.
Q-QW, R-LZ, and B-FX conceived the experiments. B-FX conducted the experiments. Q-QW, B-FX, and W-LH analysed the results. B-FX and Q-QW wrote the manuscript. All authors contributed to the review of the manuscript.
This study was funded by the Union Innovation Team Project of the Chinese Academy of Medical Sciences (2016-I2M-3021), the National Natural Science Foundation of China (81772209 and 81601804), the Natural Science Foundation of Jiangsu Province of China (BK20150121), and the PUMC Youth Fund of the Fundamental Research Funds for the Central Universities (2017310056). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Compliance with ethical standards
Conflict of interest
The authors have declared that no competing interests exist.
All animal experimentation was conducted following the Guide for the Care and Use of Laboratory Animals and according to protocols reviewed and approved by the Nanjing Military Region CDC in China. The experimental rabbits were anaesthetized with urethane and killed under air embolism by euthanasia. The project licence number (2017-KY-010) was assigned by the ethics committee that approved our animal experiments.
- 1.Cao Y, Su X, Wang Q, Xue H, Zhu X, Zhang C, Jiang J, Qi S, Gong X, Zhu X, Pan M, Ren H, Hu W, Wei Z, Tian M, Liu W (2017) A multicenter study evaluating ceftriaxone and benzathine penicillin G as treatment agents for early syphilis in Jiangsu, China. Clin Infect Dis 65(10):1683–1688. https://doi.org/10.1093/cid/cix611 CrossRefGoogle Scholar
- 2.World Health Organization (2016) Title of the subordinate document: In: Report on global sexually transmitted infection surveillance 2015, pp 14–27. https://www.who.int/reproductivehealth/publications/rtis/stissurveillance-2015/en
- 3.Chinese center for disease control and prevention (2018) Title of the subordinate document: In: Overview of the national legal infectious disease epidemic in 2017. Chinese center for disease control and prevention. http://www.nhfpc.gov.cn/jkj/s3578/201802/de926bdb046749abb7b0a8e23d929104.shtml. Accessed 26 Feb 2018
- 4.Riley BS, Oppenheimer-Marks N, Radolf JD, Norgard MV (1994) Virulent Treponema pallidum promotes adhesion of leukocytes to human vascular endothelial cells. Infect Immun 62(10):4622–4625Google Scholar
- 9.Liu X, Li Q, Niu X, Hu B, Chen S, Song W, Ding J, Zhang C, Wang Y (2017) Exosomes secreted from human-induced pluripotent stem cell-derived mesenchymal stem cells prevent osteonecrosis of the femoral head by promoting angiogenesis. Int J Biol Sci 13(2):232–244. https://doi.org/10.7150/ijbs.16951 CrossRefGoogle Scholar
- 11.Hui WW, Hercik K, Belsare S, Aluqubelly N, Clapp B, Rinaldi C, Edelmann MJ (2018) Salmonella enterica serovar typhimurium alters the extracellular proteome of macrophages and leads to the production of proinflammatory exosomes. Infect Immun 86(2):e00386–e00317. https://doi.org/10.1128/IAI.00386-17 Google Scholar
- 13.Hawley KL, Cruz AR, Benjamin SJ, La Vake CJ, Cervantes JL, LeDoyt M, Ramirez LG, Mandich D, Fiel-Gan M, Caimano MJ, Radolf JD, Salazar JC (2017) IFNγ enhances CD64-potentiated phagocytosis of Treponema pallidum opsonized with human syphilitic serum by human macrophages. Front Immunol 8:1227. https://doi.org/10.3389/fimmu.2017.01227 CrossRefGoogle Scholar
- 21.Wei F, Liu S, Luo L, Gu N, Zeng Y, Chen X, Xu S, Zhang D (2017) Anti-inflammatory mechanism of ulinastatin: Inhibiting the hyperpermeability of vascular endothelial cells induced by TNF-α via the RhoA/ROCK signal pathway. Int Immunopharmacol 46:220–227. https://doi.org/10.1021/ac200195n CrossRefGoogle Scholar
- 22.Sell S, Salman J, Norris SJ (1985) Reinfection of chancre-immune rabbits with Treponema pallidum. Am J Pathol 118:248–255. (PubMed: 3881974)Google Scholar
- 23.Radolf JD, Arndt LL, Akins DR, Curetty LL, Levi ME, Shen Y, Davis LS, Norgard MV (1995) Treponema pallidum and Borrelia burgdorferi lipoproteins and synthetic lipopeptides activate monocytes/macrophages. J Immunol 154(6):2866–2877Google Scholar
- 24.Sellati TJ, Bouis DA, Kitchens RL, Darveau RP, Pugin J, Ulevitch RJ, Gangloff SC, Goyert SM, Norgard MV, Radolf JD (1998) Treponema pallidum and Borrelia burgdorferi lipoproteins and synthetic lipopeptides activate monocytic cells via a CD14-dependent pathway distinct from that used by lipopolysaccharide. J Immunol 160(11):5455–5464Google Scholar
- 28.Shi Y, Jiang X, Zhang L, Pu H, Hu X, Zhang W, Cai W, Gao Y, Leak RK, Keep RF, Bennett MV, Chen J (2017) Endothelium-targeted overexpression of heat shock protein 27 ameliorates blood-brain barrier disruption after ischemic brain injury. Proc Natl Acad Sci USA 114(7):E1243–E1252. https://doi.org/10.1073/pnas.1621174114 CrossRefGoogle Scholar
- 30.Im E, Choi YJ, Kim CH, Fiocchi C, Pothoulakis C, Rhee SH (2009) The angiogenic effect of probiotic Bacillus polyfermenticus on human intestinal microvascular endothelial cells is mediated by IL-8. Am J Physiol Gastrointest Liver Physiol 297(5):G999–G1008. https://doi.org/10.1152/ajpgi.00204.2009 CrossRefGoogle Scholar