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

基本信息

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
项目类别：
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

项目摘要

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一个重要的例子是胃癌，它是全球至少 80% 的癌症死亡原因。的胃癌病例归因于胃部感染幽门螺杆菌 (Hp)，该细菌会导致在某些个体中，这种炎症可能会导致无法根除感染的终生慢性炎症。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 Hp+KRAS+ 小鼠也出现了“变异”凹坑细胞（表面粘液细胞）的扩张。表达与化生和癌症相关的基因，如粘蛋白 Muc4。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 细胞增加了倍数在本提案中，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。我认为幽门螺杆菌通过调节炎症反应来预防幽门螺杆菌。从胃中根除，这种有害的免疫反应会导致化生和发育异常。将进行 CD4+ 和 CD8α+ T 细胞亚群的靶向清除，以评估免疫扰动是否会产生影响我还将评估 Hp+KRAS+ 中 T 细胞是否流入胃。最后，我将测试 Hp+ 人类样本相对于 Hp- 是否有增加的 T 细胞。在目标 2 中，我将研究调节炎症的候选 Hp 毒力因子：cag IV 型。我将确定分泌系统和调节 T 细胞的两种蛋白质：毒素 VacA 和转肽酶 gGT。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在目标 3 中，我将测试变异型凹陷细胞是否由胃祖细胞产生。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我还将在 +/- Hp、+/- KRAS 小鼠中进行空间单细胞 RNA 测序，以确定是否存在转化。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。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这些发现也可能适用于其他疾病。与细菌感染和/或炎症相关的癌症，如结直肠癌。