Mondal Ayan, Tapader Rima, Chatterjee Nabendu Sekhar, Ghosh Amit, Sinha Ritam, Koley Hemanta, Saha Dhira Rani, Chakrabarti Manoj K, Wai Sun Nyunt, Pal Amit
Division of Pathophysiology, National Institute of Cholera and Enteric Diseases, Kolkata, India.
Division of Biochemistry, National Institute of Cholera and Enteric Diseases, Kolkata, India.
Infect Immun. 2016 Apr 22;84(5):1478-1490. doi: 10.1128/IAI.01365-15. Print 2016 May.
Proteases in Vibrio cholerae have been shown to play a role in its pathogenesis. V. cholerae secretes Zn-dependent hemagglutinin protease (HAP) and calcium-dependent trypsin-like serine protease (VesC) by using the type II secretion system (TIISS). Our present studies demonstrated that these proteases are also secreted in association with outer membrane vesicles (OMVs) and transported to human intestinal epithelial cells in an active form. OMV-associated HAP induces dose-dependent apoptosis in Int407 cells and an enterotoxic response in the mouse ileal loop (MIL) assay, whereas OMV-associated VesC showed a hemorrhagic fluid response in the MIL assay, necrosis in Int407 cells, and an increased interleukin-8 (IL-8) response in T84 cells, which were significantly reduced in OMVs from VesC mutant strain. Our results also showed that serine protease VesC plays a role in intestinal colonization of V. cholerae strains in adult mice. In conclusion, our study shows that V. cholerae OMVs secrete biologically active proteases which may play a role in cytotoxic and inflammatory responses.
霍乱弧菌中的蛋白酶已被证明在其发病机制中起作用。霍乱弧菌通过II型分泌系统（TIISS）分泌锌依赖性血凝素蛋白酶（HAP）和钙依赖性胰蛋白酶样丝氨酸蛋白酶（VesC）。我们目前的研究表明，这些蛋白酶也与外膜囊泡（OMV）一起分泌，并以活性形式转运到人类肠道上皮细胞。与OMV相关的HAP在Int407细胞中诱导剂量依赖性凋亡，并在小鼠回肠袢（MIL）试验中引起肠毒素反应，而与OMV相关的VesC在MIL试验中表现出出血性液体反应，在Int407细胞中引起坏死，并在T84细胞中引起白细胞介素-8（IL-8）反应增加，这在来自VesC突变株的OMV中显著降低。我们的结果还表明，丝氨酸蛋白酶VesC在成年小鼠霍乱弧菌菌株的肠道定殖中起作用。总之，我们的研究表明，霍乱弧菌OMV分泌具有生物活性的蛋白酶，这些蛋白酶可能在细胞毒性和炎症反应中起作用。
