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.

项目摘要 许多癌症归因于慢性炎症，这会引起突变并激活致癌信号传导 途径。一个重要的例子是胃癌，这是全球癌症死亡的第四个领先原因。至少80％ 胃癌病例归因于幽门螺杆菌幽门螺杆菌（HP）的失速感染，这引起了 终生的慢性感染不会放射性感染。在某些人中，这种感染可能导致 胃萎缩，化生（将一种正常细胞类型转化为另一种细胞类型），发育不良（存在异常 细胞）和最后的癌症，但是HP触发该级联的特定机制不好 理解齿。通过他莫昔芬诱导的小鼠模型中概括了类似的前塑性变化 活性KRA在摊位的主要细胞（KRAS+小鼠）中的表达。我发现KRAS+小鼠的HP感染 恶化的疾病：与HP-KRAS+小鼠相比，HP+ KRAS+小鼠的化生轨迹和 加速发育不良。 HP+ KRAS+小鼠还具有“变体”坑细胞（表面粘液细胞）的扩展 表达的化生和癌症相关基因（如粘蛋白MUC4）。根据HP的假设 通过引起慢性感染引起癌症，HP+ KRAS+小鼠患有严重感染。 T细胞与HP-KRAS+小鼠的折叠增加。在此提案中，我将研究HP的机制 KRAS+小鼠的疾病恶化，其更广泛的目标是更好地了解HP感染及其相关的方式 慢性炎症会导致癌症。我假设HP调节炎症反应以防止HP 从摊位中消除，这种有害的免疫响应会导致化生和发育不良。在目标1 i 将执行针对CD4+和CD8α+ T细胞子集的目标耗竭，以评估免疫扰动是否影响 化生，发育不良和HP定殖。我还将评估T细胞是否在HP+KRAS+中流动到摊位 小鼠或局部增殖。最后，我将测试HP+人类样品相对于HP-的T细胞是否增加了T细胞 样品。在AIM 2中，我将调查调节注射的候选HP病毒因子：IV型CAG 分泌系统和两个调节T细胞的蛋白质，毒素VACA和转肽酶GGT。我会确定 病毒因子突变体是否可以在KRAS+中引起相同的炎症和疾病进展表型 像野生型HP一样的小鼠。在AIM 3中，我将测试变体细胞是否来自胃祖细胞，并将 评估HP+KRAS+MUC4-小鼠中的疾病表型，以确定MUC4表达是否驱动PIT细胞 转型。我还将在+/- hp，+/- kras小鼠中进行空间单细胞RNA测序以发现是否是否 变体坑细胞在摊位的“第一腺”中与表达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。总之，结果 这些研究将为HP感染和注射如何引起胃肿瘤性提供新的了解 进展并可能揭示了胃免疫疗法的新靶标。这些发现也可能适用于其他 与细菌感染和/或感染相关的癌症，例如结直肠癌。