Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, University of South China, Hengyang City, Hunan Province, 421001, People's Republic of China.
Center of Medical Laboratory, Affiliated the First People's Hospital of Chenzhou of University of South China, Chenzhou, 423000, China.
Appl Microbiol Biotechnol. 2022 Oct;106(19-20):6657-6669. doi: 10.1007/s00253-022-12146-z. Epub 2022 Sep 6.
By interacting with the receptor on the host cells membrane, Mycoplasma genitalium, a prokaryotic bacterium primarily transmitted through sexual contact, can adhere to and even enter cells. The adhesion protein of M. genitalium (MgPa) plays a critical function in the adhering and subsequent invasion into host cells. Our prior studies verified that cyclophilin A (CypA) was the receptor of MgPa on human urethral epithelial cells (SV-HUC-1) membrane and could induce pro-inflammatory cytokines production through the CypA-CD147-ERK-NF-κB pathway. This research aims to understand how MgPa interacts with its membrane receptor CypA to cause apoptosis in host cells. We employed flow cytometry to see if MgPa prevents or enhances apoptosis of SV-HUC-1 cells. The apoptosis-related proteins such as Bax, caspase-3, and cleaved caspase-3 were assayed using Western blot. Results suggested that MgPa could inhibit the apoptosis of SV-HUC-1 cells. And we demonstrated that interference with the expression of CypA or CD147 significantly reversed the inhibitory effect of MgPa on SV-HUC-1 cells apoptosis, indicating that MgPa inhibited urothelial cells apoptosis through CypA/CD147. Furthermore, we discovered that MgPa regulates the PI3K/Akt/NF-κB pathway through CypA/CD147 to inhibit SV-HUC-1 cells apoptosis. Ultimately, the inhibitory effect of MgPa on the apoptosis of the urothelial epithelial cells extracted from CypA-knockout mice was validated by Annexin V/PI assay. The results corroborated that MgPa could also inhibit mouse urothelial epithelial cells apoptosis. In summary, we demonstrated that MgPa could inhibit SV-HUC-1 cells apoptosis via regulating the PI3K/Akt/NF-κB pathway through CypA/CD147, providing experimental evidence for elucidating the survival strategies of M. genitalium in host cells. KEY POINTS: • M. genitalium protein of adhesion inhibited human urethral epithelial cells apoptosis through CypA-CD147 activating the signal pathway of PI3K/Akt/NF-κB • The knockdown of CypA and CD147 could downregulate the M. genitalium -activated PI3K/Akt/NF-κB pathway in SV-HUC-1 cells • MgPa could inhibit the apoptosis of normal C57BL mouse primary urethral epithelial cells, but not for CypA-knockout C57BL mouse primary urethral epithelial cells.
通过与宿主细胞膜上的受体相互作用，主要通过性接触传播的原核细菌生殖支原体（Mycoplasma genitalium）可以黏附甚至进入细胞。生殖支原体的黏附蛋白（MgPa）在黏附和随后进入宿主细胞中起着关键作用。我们之前的研究证实，亲环素 A（CypA）是人尿道上皮细胞（SV-HUC-1）膜上 MgPa 的受体，可通过 CypA-CD147-ERK-NF-κB 通路诱导促炎细胞因子的产生。本研究旨在了解 MgPa 如何与膜受体 CypA 相互作用，导致宿主细胞凋亡。我们采用流式细胞术观察 MgPa 是否阻止或增强 SV-HUC-1 细胞凋亡。使用 Western blot 测定 Bax、caspase-3 和 cleaved caspase-3 等与凋亡相关的蛋白。结果表明，MgPa 可抑制 SV-HUC-1 细胞凋亡。并且我们证明，干扰 CypA 或 CD147 的表达可显著逆转 MgPa 对 SV-HUC-1 细胞凋亡的抑制作用，表明 MgPa 通过 CypA/CD147 抑制尿路上皮细胞凋亡。此外，我们发现 MgPa 通过 CypA/CD147 调节 PI3K/Akt/NF-κB 通路抑制 SV-HUC-1 细胞凋亡。最终，通过 Annexin V/PI 检测验证了 MgPa 对 CypA 敲除小鼠提取的尿路上皮细胞凋亡的抑制作用。结果证实，MgPa 还可以抑制小鼠尿路上皮细胞凋亡。总之，我们通过 CypA/CD147 证实 MgPa 可通过调节 PI3K/Akt/NF-κB 通路抑制 SV-HUC-1 细胞凋亡，为阐明生殖支原体在宿主细胞中的生存策略提供了实验依据。
生殖支原体黏附蛋白通过激活 CypA-CD147 信号通路抑制人尿道上皮细胞凋亡，从而激活 PI3K/Akt/NF-κB 信号通路
CypA 和 CD147 的敲低可下调 SV-HUC-1 细胞中生殖支原体激活的 PI3K/Akt/NF-κB 通路
MgPa 可抑制正常 C57BL 小鼠原代尿道上皮细胞凋亡，但不能抑制 CypA 敲除 C57BL 小鼠原代尿道上皮细胞凋亡。
