Immunoregulatory Defects In Inflammatory Bowel Disease

炎症性肠病的免疫调节缺陷

• 批准号: 6674046
• 负责人: WARREN STROBER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6674046
• 关键词: Crohn's disease; T cell receptor; confocal scanning microscopy; cytokine; enzyme linked immunosorbent assay; flow cytometry; helper T lymphocyte; human subject; immunopathology; immunoregulation; inflammatory bowel diseases; interferon gamma; interleukin 10; interleukin 12; intestinal mucosa; laboratory mouse; mucosal immunity; patient oriented research; tissue /cell culture; transforming growth factors

Project 1: Defined Th1 responses causing intestinal inflammation such as that occurring in SJL/J mice with TNBS-colitis offer an excellent opportunity to identify genetic loci (and ultimately defined genes) that are responsible for the colitis. This approach is facilitated by the fact that there is enormous mouse strain variability in susceptibility to TNBS-colitis: SJL/J mice and C57BL/10 mice are highly susceptible whereas C25BL/6 mice are highly resistant. Accordingly, we conducted an extensive genome-wide linkage analysis in F2 progeny of SJL/J and C57BL/6 mice by identifying susceptible and resistant progeny and then correlating that with multiple chromosomal markers associated with the two strains. This analysis led to the identification of two susceptibility loci, one on chromosome 9 and one on chromosome 11 called TNBS1 and TNBS2 respectively. Furthermore, while TNBS was strongly associated with disease in male mice, it was relatively weakly associated with disease in females. Conversely, while TNBS was strongly associated with disease in female mice, it was not associated with disease in male mice. However, further analysis of resistant male mice negative for TNBS1 revealed an association with TNBS2; thus, both male and female mice have a susceptibility locus on chromosome 11. Recognizing that locus on chromosome 11 contains the IL-12 gene, we conducted futher studies to identify IL-12 response abnormalities that might also map to this locus. Accordingly, we administered IP LPS to SJL/J and C57BL/6 mice and showed that whereas IL-12 p40 production induced by the LPS was equivalent in the two strains, the amount of IL-12 p70 was vastly greater in the SJL/J strain than in the C57BL/6 strain. We then conducted further genome-analysis to map this difference in responses and found that the ability to mount a high IL-12 p70 response mapped to the SJL/J chromosome 11 allele. Thus, these data were strongly suggestive that a genetic abnormality involving the IL-12 gene is partly responsible for susceptibility to TNBS-colitis. This conclusion was also supported by the fact that male C57BL/10 mice whose genome is 99% identical to that of C57BL/6 mice and differs largely at the chromosome 11 susceptibility region, is also susceptible to TNBS-colitis and mounts a high LPS-induced IL-12 p70 response. Finally, it is important to note that a human chromosome region on human chromosome 5 (5q33-34) syntenic to the TNBS2 on chromosome 11 has been linked to human Crohn?s disease: on this basis, TNBS2 may have relevance to the human disease.

项目一：引起肠道炎症的确定的Th 1应答，例如发生在患有TNBS-结肠炎的SJL/J小鼠中的应答，提供了鉴定导致结肠炎的遗传基因座（和最终确定的基因）的极好机会。这种方法是由TNBS结肠炎的易感性存在巨大的小鼠品系变异性的事实促进的：SJL/J小鼠和C57 BL/10小鼠高度易感，而C25 BL/6小鼠高度耐药。因此，我们在SJL/J和C57 BL/6小鼠的F2后代中进行了广泛的全基因组连锁分析，通过鉴定易感和耐药后代，然后将其与两种品系相关的多个染色体标记相关联。该分析导致鉴定了两个易感性基因座，一个在9号染色体上，一个在11号染色体上，分别称为TNBS 1和TNBS 2。此外，虽然TNBS与雄性小鼠的疾病密切相关，但与雌性小鼠的疾病相关性相对较弱。相反，虽然TNBS与雌性小鼠的疾病密切相关，但与雄性小鼠的疾病无关。然而，对TNBS 1阴性的抗性雄性小鼠的进一步分析揭示了与TNBS 2的关联;因此，雄性和雌性小鼠在11号染色体上都具有易感性基因座。认识到11号染色体上的位点含有IL-12基因，我们进行了进一步的研究，以确定IL-12反应异常，也可能映射到这个位点。因此，我们将IP LPS给予SJL/J和C57 BL/6小鼠，并显示尽管LPS诱导的IL-12 p40产生在两种品系中是相等的，但IL-12 p70的量在SJL/J品系中比在C57 BL/6品系中大得多。然后，我们进行了进一步的基因组分析，以映射这种差异的反应，并发现安装一个高IL-12 p70反应的能力映射到SJL/J染色体11等位基因。因此，这些数据强烈表明，涉及IL-12基因的遗传异常是导致TNBS结肠炎易感性的部分原因。这一结论也得到以下事实的支持，即基因组与C57 BL/6小鼠的基因组99%相同并且在染色体11易感区域差异很大的雄性C57 BL/10小鼠也对TNBS结肠炎易感并且产生高LPS诱导的IL-12 p70应答。最后，重要的是要注意，人类染色体5（5 q33 -34）同线的TNBS 2染色体11上的人类染色体区域已与人类克罗恩病？在此基础上，TNBS 2可能与人类疾病有关。