Department of Molecular Genetics, Biochemistry, and Microbiology, Cincinnati OH, United States of America.
Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati OH, United States of America.
PLoS Pathog. 2019 Jan 31;15(1):e1007468. doi: 10.1371/journal.ppat.1007468. eCollection 2019 Jan.
Helicobacter pylori (H. pylori) is the major risk factor for the development of gastric cancer. Our laboratory has reported that the Sonic Hedgehog (Shh) signaling pathway is an early response to infection that is fundamental to the initiation of H. pylori-induced gastritis. H. pylori also induces programmed death ligand 1 (PD-L1) expression on gastric epithelial cells, yet the mechanism is unknown. We hypothesize that H. pylori-induced PD-L1 expression within the gastric epithelium is mediated by the Shh signaling pathway during infection. To identify the role of Shh signaling as a mediator of H. pylori-induced PD-L1 expression, human gastric organoids generated from either induced pluripotent stem cells (HGOs) or tissue (huFGOs) were microinjected with bacteria and treated with Hedgehog/Gli inhibitor GANT61. Gastric epithelial monolayers generated from the huFGOs were also infected with H. pylori and treated with GANT61 to study the role of Hedgehog signaling as a mediator of induced PD-1 expression. A patient-derived organoid/autologous immune cell co-culture system infected with H. pylori and treated with PD-1 inhibitor (PD-1Inh) was developed to study the protective mechanism of PD-L1 in response to bacterial infection. H. pylori significantly increased PD-L1 expression in organoid cultures 48 hours post-infection when compared to uninfected controls. The mechanism was cytotoxic associated gene A (CagA) dependent. This response was blocked by pretreatment with GANT61. Anti-PD-L1 treatment of H. pylori infected huFGOs, co-cultured with autologous patient cytotoxic T lymphocytes and dendritic cells, induced organoid death. H. pylori-induced PD-L1 expression is mediated by the Shh signaling pathway within the gastric epithelium. Cells infected with H. pylori that express PD-L1 may be protected from the immune response, creating premalignant lesions progressing to gastric cancer.
幽门螺杆菌（H. pylori）是胃癌发展的主要危险因素。我们的实验室已经报告，Sonic Hedgehog（Shh）信号通路是感染的早期反应，对于启动 H. pylori 诱导的胃炎至关重要。H. pylori 还诱导胃上皮细胞程序性死亡配体 1（PD-L1）的表达，但机制尚不清楚。我们假设 H. pylori 感染时 Shh 信号通路在胃上皮细胞中诱导 PD-L1 的表达。为了确定 Shh 信号通路作为 H. pylori 诱导的 PD-L1 表达的介质的作用，我们用人诱导多能干细胞（HGOs）或组织（huFGOs）生成的胃类器官进行细菌微注射，并接受 Hedgehog/Gli 抑制剂 GANT61 处理。还从 huFGOs 中生成的胃上皮细胞单层感染 H. pylori 并接受 GANT61 处理，以研究 Hedgehog 信号作为诱导 PD-1 表达的介质的作用。开发了一种患者衍生的类器官/自体免疫细胞共培养系统，用于感染 H. pylori 并接受 PD-1 抑制剂（PD-1Inh）处理，以研究 PD-L1 对细菌感染的保护机制。与未感染对照相比，感染后 48 小时，H. pylori 显著增加了类器官培养物中的 PD-L1 表达。该机制依赖于细胞毒素相关基因 A（CagA）。预处理用 GANT61 可阻断该反应。用抗 PD-L1 处理 H. pylori 感染的 huFGOs，与自体患者细胞毒性 T 淋巴细胞和树突状细胞共培养，诱导类器官死亡。H. pylori 在胃上皮细胞中诱导的 PD-L1 表达是由 Shh 信号通路介导的。表达 PD-L1 的 H. pylori 感染细胞可能免受免疫反应的保护，从而产生进展为胃癌的癌前病变。
