Novel Role of DRA/SLC26A3 Downregulation in Gut Dysbiosis, Inflammation and Infection

DRA/SLC26A3 下调在肠道菌群失调、炎症和感染中的新作用

• 批准号: 10909515
• 负责人: Pradeep K Dudeja
• 金额: $ 53.34万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-20 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10909515
• 关键词: Affect; Age; Antibiotic Therapy; Bacteria; Bicarbonates; Butyrates; CRISPR/Cas technology; Cells; Chlorides; Citrobacter rodentium; Colitis; Colon; Data; Defect; Diarrhea; Disease; Down-Regulation; Electrolytes; Epithelium; Event; Exhibits; Feces; Genes; Genetic Predisposition to Disease; Germ-Free; Goblet Cells; Human; Immune; Immunology; Impairment; Infection; Inflammation; Inflammatory Bowel Diseases; Inflammatory Response; Intervention; Intestines; Knock-out; Knockout Mice; Lymphoid Cell; Metagenomics; Microclimate; Modeling; Mucin-2 Staining Method; Mucins; Mucous body substance; Mus; Pathogenicity; Phenotype; Predisposition; Production; Regulation; Role; SLC26A3 gene; Secondary to; Sodium Bicarbonate; Structure; Susceptibility Gene; Testing; Thinness; Time; Transgenic Mice; Tretinoin; Volatile Fatty Acids; Water; Wild Type Mouse; absorption; age related; design; drinking water; dysbiosis; efficacy evaluation; fecal transplantation; genome wide association study; gut dysbiosis; gut inflammation; gut microbiome; insight; interleukin-22; intestinal barrier; loss of function mutation; metabolomics; microbial; microbiome; microbiome alteration; nano-string; new therapeutic target; novel; overexpression; pathogen; receptor; response; restoration; transcriptome sequencing; tributyrin

Down regulated in adenoma (DRA) or SLC26A3 is the key intestinal chloride transporter involved in electrolyte and water absorption in the gut. Loss of function mutations in DRA result in “Congenital Chloride Diarrhea” or CLD disease. Extensive studies from our group have now established that downregulation of DRA is one of the key events in infectious and IBD-associated diarrhea. Emerging evidence from our group and others and GWAS studies have now also established DRA gene to be an IBD susceptibility locus. DRA knockout (KO) mice exhibit a CLD phenotype, thinner mucus layer and increased susceptibility to colitis. We recently showed that DRA KO mice exhibit some of the key features of IBD, including dysbiosis and compromised barrier integrity. Our preliminary studies further showed that DRA KO mice are more susceptible to pathogen infection and exhibit immune cell dysregulation. However, the detailed mechanisms underlying dysbiosis and its role in defective mucus-epithelial barrier observed in DRAKO mice and their increased susceptibility to gut inflammation and pathogen infection have not been fully investigated. Our exciting data further showed that the dysbiosis in DRA KO mice was associated with decreased short chain fatty acid (SCFA) producing taxa, fecal SCFA levels and enrichment in mucin-degrading bacteria. Cohousing studies of DRA KO with wildtype mice showed that part of the compromised barrier integrity was secondary to microbial dysbiosis. Further, in preliminary studies, DRA KO mice showed a marked reduction in Innate Lymphoid Cells-3 and IL-22, critical for combating pathogen infection. Preliminary data also showed that the expression of key mucins (MUC2 and 4) was significantly higher in goblet cells but appeared to be trapped in cells suggesting abnormal secretion. Based upon these findings, our overall hypothesis is that “Gut dysbiosis in response to the loss of DRA function contribute to compromised mucus and epithelial barrier integrity leading to increased susceptibility to gut inflammation and pathogen infection and strategies to upregulate DRA expression may alleviate these effects”. The key component of this hypothesis for this R56 proposal will be tested by the following Specific Aims: Aim 1a: Examine the age-dependent dynamic changes in the microbiome and mucus and epithelial barrier defects in DRA KO mice; Aim 1b: Investigate if cohousing with WT mice modulates the epithelium-associated factors including TJs, mucin synthesis and secretion; Aim 1c: Examine the role of altered bacterial species and metabolites by in-depth metabolomic and metagenomic analysis in DRA KO mice; Aim 1d: Evaluate the role of altered microbiome in affecting mucus layer and epithelial integrity via fecal microbial transplant approaches from WT and DRA KO mice to GF mice. The proposed studies will provide mechanistic insights into the role of DRA induced dysbiosis in defective mucus and epithelial barrier integrity and susceptibility to inflammation and infection and may aid in unraveling novel therapeutic targets.

腺瘤 (DRA) 中下调的 SLC26A3 是参与肠道电解质和水吸收的关键肠道氯离子转运蛋白。 DRA 功能缺失突变会导致“先天性氯化物腹泻”或 CLD 疾病。我们小组的广泛研究现已证实，DRA 的下调是感染性腹泻和 IBD 相关性腹泻的关键事件之一。我们小组和其他人的新证据以及 GWAS 研究现在也确定 DRA 基因是 IBD 易感位点。 DRA 基因敲除 (KO) 小鼠表现出 CLD 表型、粘液层变薄以及对结肠炎的易感性增加。我们最近发现 DRA KO 小鼠表现出 IBD 的一些关键特征，包括生态失调和屏障完整性受损。我们的初步研究进一步表明，DRA KO 小鼠更容易受到病原体感染，并表现出免疫细胞失调。然而，生态失调的详细机制及其在粘液上皮屏障缺陷中的作用 DRAKO 小鼠及其对肠道炎症和病原体感染的易感性增加尚未得到充分研究。我们令人兴奋的数据进一步表明，DRA KO 小鼠的生态失调与产生短链脂肪酸 (SCFA) 的分类群、粪便 SCFA 水平和粘蛋白降解细菌富集的减少有关。 DRA KO 与野生型小鼠的同居研究表明，屏障完整性受损的部分原因是微生物失调。此外，在初步研究中，DRA KO 小鼠的先天淋巴细胞 3 和 IL-22 显着减少，这对于对抗病原体感染至关重要。初步数据还表明，杯状细胞中关键粘蛋白（MUC2和4）的表达显着较高，但似乎被困在细胞中，表明分泌异常。基于这些发现，我们的总体假设是“DRA 功能丧失导致的肠道菌群失调导致 “粘液和上皮屏障完整性受损，导致肠道炎症和病原体感染的易感性增加，而上调 DRA 表达的策略可能会减轻这些影响。”R56 提案的这一假设的关键组成部分将通过以下具体目标进行测试：目标 1a：检查 DRA KO 中微生物组以及粘液和上皮屏障缺陷的年龄依赖性动态变化 老鼠；目标 1b：调查与 WT 小鼠共养是否会调节上皮相关因子，包括 TJ、粘蛋白合成和分泌；目标 1c：通过 DRA KO 小鼠的深入代谢组学和宏基因组分析，检查改变的细菌种类和代谢物的作用；目标 1d：评估改变的微生物组在影响粘液层和上皮细胞中的作用 通过粪便微生物移植方法从 WT 和 DRA KO 小鼠到 GF 小鼠的完整性。拟议的研究将为 DRA 诱导的菌群失调在有缺陷的粘液和上皮屏障完整性以及对炎症和感染的易感性中的作用提供机制见解，并可能有助于揭示新的治疗靶点。