Investigating gastric inflammation and preneoplastic progression driven by Helicobacter pylori infection

研究幽门螺杆菌感染驱动的胃部炎症和癌前进展

• 批准号: 10661588
• 负责人: Valerie Phoebe O'Brien
• 金额: $ 16.78万
• 依托单位: FRED HUTCHINSON CANCER CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-07 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10661588
• 关键词: Abnormal Cell; Acceleration; Alleles; Atrophic Gastritis; Bacteria; Bacterial Infections; Cancer Etiology; Carcinoma; Cell Line; Cell Lineage; Cells; Cessation of life; Chronic; Colorectal Cancer; Cytotoxin; Development; Disease; Disease Progression; Dysplasia; Environment; Gastric Acid; Gastric Chief Cells; Gastric Metaplasia; Gastric Parietal Cells; Gastritis; Gene Expression; Gene Expression Profile; Genes; Gland; Goals; Guanosine Triphosphate Phosphohydrolases; Helicobacter Infections; Helicobacter pylori; Human; Immune; Immune response; Immunity; Immunotherapy; In Situ Hybridization; Individual; Infection; Infiltration; Inflammation; Inflammatory; Inflammatory Response; Intestinal Metaplasia; Intestines; KRAS2 gene; MUC4 mucin; Malignant Neoplasms; Mediating; Metaplasia; Modeling; Morphology; Mucous body substance; Mus; Mutation; Normal Cell; Oncogenic; PTPRC gene; Pathway interactions; Peptidyltransferase; Phenotype; Preneoplastic Change; Proliferating; Protein Secretion; Proteins; Research; Role; Sampling; Series; Signal Pathway; Signaling Protein; Source; Splenocyte; Stomach; Surface; T-Cell Proliferation; T-Lymphocyte; T-Lymphocyte Subsets; T-cell inflamed; Tamoxifen; Techniques; Testing; Tissues; Toxin; Transgenic Organisms; Type IV Secretion System Pathway; Variant; Virulence; Virulence Factors; cancer immunotherapy; cancer risk; cell transformation; cell type; congenic; disease phenotype; experimental study; genetic approach; immunopathology; inflammatory modulation; insight; malignant stomach neoplasm; mouse model; mutant; novel; polarized cell; premalignant; prevent; progenitor; programs; protein expression; repaired; single cell sequencing; single-cell RNA sequencing; stem cells; tumor progression

Project Summary Many cancers are attributed to chronic inflammation, which can cause mutations and activate oncogenic signaling pathways. An important example is gastric cancer, the fourth-leading cause of cancer death worldwide. At least 80% of gastric cancer cases are attributed to stomach infection with the bacterium Helicobacter pylori (Hp), which causes lifelong chronic inflammation that does not eradicate the infection. In some individuals, this inflammation can cause gastric atrophy, metaplasia (conversion of one normal cell type to another), dysplasia (presence of abnormal cells) and finally cancer, but the specific mechanism(s) through which Hp triggers this cascade are not well understood. Similar preneoplastic changes are recapitulated in a mouse model through tamoxifen-induced expression of active KRAS in the chief cells of the stomach (KRAS+ mice). I found that Hp infection of KRAS+ mice exacerbated disease: compared to Hp-KRAS+ mice, Hp+KRAS+ mice had an altered trajectory of metaplasia and accelerated dysplasia. Hp+KRAS+ mice also had expansion of “variant” pit cells (surface mucous cells) that expressed metaplasia- and cancer-related genes like the mucin Muc4. In accordance with the hypothesis that Hp causes cancer through eliciting chronic inflammation, Hp+KRAS+ mice had severe inflammation marked by a ten- fold increase in T cells vs. Hp-KRAS+ mice. In this proposal I will investigate the mechanism(s) through which Hp worsens disease in KRAS+ mice, with a broader goal of better understanding how Hp infection and its associated chronic inflammation cause cancer. I hypothesize that Hp modulates the inflammatory response to prevent Hp eradication from the stomach, and this deleterious immune response leads to metaplasia and dysplasia. In Aim 1 I will perform targeted depletion of CD4+ and CD8α+ T cell subsets to assess whether immune perturbation impacts metaplasia, dysplasia and Hp colonization. I will also assess whether T cells traffic to the stomach in Hp+KRAS+ mice or proliferate locally. Finally, I will test whether Hp+ human samples have increased T cells relative to Hp- samples. In Aim 2 I will investigate candidate Hp virulence factors that modulate inflammation: the cag type IV secretion system and two proteins that modulate T cells, the toxin VacA and the transpeptidase gGT. I will determine whether virulence factor mutants can elicit the same inflammatory and disease progression phenotypes in KRAS+ mice as wild-type Hp does. In Aim 3 I will test whether variant pit cells arise from gastric progenitor cells, and will assess disease phenotypes in Hp+KRAS+MUC4- mice to determine whether Muc4 expression drives pit cell transformation. I will also perform spatial single-cell RNA sequencing in +/- Hp, +/- KRAS mice to discover whether variant pit cells share a gene expression signature with Muc4-expressing cells in the “first gland” of the stomach, a morphologically distinct gland that is believed to be a source of reparative cell lineages. Taken together, the results of these studies will provide new understanding of how Hp infection and inflammation cause gastric preneoplastic progression and may reveal new targets for gastric immunotherapy. These findings may also be applicable to other cancers associated with bacterial infection and/or inflammation, like colorectal cancer.

项目概要 许多癌症归因于慢性炎症，慢性炎症可能导致突变并激活致癌信号 途径。一个重要的例子是胃癌，它是全球第四大癌症死亡原因。至少80% 的胃癌病例归因于胃部感染幽门螺杆菌 (Hp)，该细菌会导致 终生慢性炎症，无法根除感染。在某些人中，这种炎症可能会导致 胃萎缩、化生（一种正常细胞类型转变为另一种细胞类型）、发育异常（存在异常细胞） 细胞），最后是癌症，但 Hp 触发这一级联的具体机制尚不清楚 明白了。通过他莫昔芬诱导，在小鼠模型中重现了类似的肿瘤前变化 胃主细胞中活性 KRAS 的表达（KRAS+ 小鼠）。我发现KRAS+小鼠的Hp感染 病情加重：与 Hp-KRAS+ 小鼠相比，Hp+KRAS+ 小鼠的化生轨迹发生了改变，并且 加速发育异常。 Hp+KRAS+ 小鼠的“变异”凹坑细胞（表面粘液细胞）也有扩增， 表达与化生和癌症相关的基因，如粘蛋白 Muc4。根据 Hp 的假设 通过引发慢性炎症导致癌症，Hp+KRAS+ 小鼠患有严重的炎症，其特征为 10- 与 Hp-KRAS+ 小鼠相比，T 细胞增加了数倍。在本提案中，我将研究 HP 的机制 使 KRAS+ 小鼠的疾病恶化，其更广泛的目标是更好地了解 Hp 感染及其相关的机制 慢性炎症会导致癌症。我假设 Hp 调节炎症反应以预防 Hp 从胃中根除，这种有害的免疫反应会导致化生和发育不良。目标 1 I 将进行 CD4+ 和 CD8α+ T 细胞亚群的定向清除，以评估免疫扰动是否会产生影响 化生、异型增生和 Hp 定植。我还将评估 Hp+KRAS+ 中 T 细胞是否运输到胃 小鼠或局部增殖。最后，我将测试Hp+人类样本相对于Hp-是否有增加的T细胞 样品。在目标 2 中，我将研究调节炎症的候选 Hp 毒力因子：cag IV 型 分泌系统和两种调节 T 细胞的蛋白质：毒素 VacA 和转肽酶 gGT。我会确定 毒力因子突变体是否可以在 KRAS+ 中引发相同的炎症和疾病进展表型 小鼠与野生型 Hp 一样。在目标 3 中，我将测试变异凹坑细胞是否源自胃祖细胞，并将 评估 Hp+KRAS+MUC4- 小鼠的疾病表型以确定 Muc4 表达是否驱动凹陷细胞 转变。我还将在 +/- Hp、+/- KRAS 小鼠中进行空间单细胞 RNA 测序，以发现是否 变异的凹坑细胞与胃“第一腺体”中表达 Muc4 的细胞共享基因表达特征， 形态上不同的腺体，被认为是修复细胞谱系的来源。综合起来，结果 这些研究将为Hp感染和炎症如何导致胃肿瘤前期提供新的认识 进展并可能揭示胃免疫治疗的新靶点。这些发现也可能适用于其他 与细菌感染和/或炎症相关的癌症，如结直肠癌。