Departamento y Posgrado en Inmunología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional (ENCB-IPN), Mexico 11350, Mexico.
Departamento de Biomedicina Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico 07360, Mexico.
Cells. 2022 Jun 29;11(13):2061. doi: 10.3390/cells11132061.
is a Gram-negative bacterium known to be the major cause of gastrointestinal diseases and systemic infections. During infection of murine B cells, activates the PI3K/Akt pathway through its effector, SopB. This signaling pathway induces the downregulation of NLRC4 transcription, resulting in reduced secretion of IL-1β. Thus, -infected B cells do not progress to pyroptosis; consequently, the bacteria can survive inside these cells. However, the mechanism by which evades the control of B cells has not yet been elucidated. In this study, we found that SopB activates mTORC1, which is necessary for bacterial survival, since B cells cultured with the mTORC1 inhibitor rapamycin and B cells lacking raptor can control infection. A similar result was observed in B cells when they were infected with the SopB mutant (Δsopb). also promoted the phosphorylation of the ULK1 complex at serine 757 (Ser757) by mTORC1, resulting in decreased levels of LC3-II in infected B cells. In this study, we did not observe these results when B cells were infected with Δsopb . Our results demonstrated that survival within B cells depends on the inhibition of autophagy by mTORC1 activation.
是一种革兰氏阴性菌,已知是胃肠道疾病和全身感染的主要原因。在感染鼠 B 细胞时,其效应蛋白 SopB 通过激活 PI3K/Akt 途径。该信号通路诱导 NLRC4 转录下调,导致 IL-1β分泌减少。因此,感染的 B 细胞不会进展为细胞焦亡;因此,细菌可以在这些细胞内存活。然而,尚未阐明逃避 B 细胞控制的机制。在这项研究中,我们发现 SopB 激活了 mTORC1,这对于细菌的存活是必要的,因为用 mTORC1 抑制剂雷帕霉素培养的 B 细胞和缺乏 raptor 的 B 细胞可以控制感染。在感染 SopB 突变体(Δ sopb )的 B 细胞中观察到类似的结果。还通过 mTORC1 促进 ULK1 复合物在丝氨酸 757(Ser757)处的磷酸化,导致感染的 B 细胞中 LC3-II 水平降低。在本研究中,当 B 细胞感染Δ sopb 时,我们没有观察到这些结果。我们的结果表明,B 细胞内的存活取决于 mTORC1 激活对自噬的抑制。