Institute of Systems, Molecular and Integrative Biology, Faculty of Health & Life Sciences, University of Liverpool, Liverpool, United Kingdom.
Department of Biochemistry and Biotechnology, School of Health Sciences, University of Thessaly, Larissa, Greece.
Am J Physiol Gastrointest Liver Physiol. 2022 Oct 1;323(4):G306-G317. doi: 10.1152/ajpgi.00037.2022. Epub 2022 Aug 2.
The alternative (noncanonical) nuclear factor-κB (NF-κB) signaling pathway predominantly regulates the function of the p52/RelB heterodimer. Germline 2 deficiency in mice leads to loss of p100/p52 protein and offers protection against a variety of gastrointestinal conditions, including azoxymethane/dextran sulfate sodium (DSS)-induced colitis-associated cancer and lipopolysaccharide (LPS)-induced small intestinal epithelial apoptosis. However, the common underlying protective mechanisms have not yet been fully elucidated. We applied high-throughput RNA-Seq and proteomic analyses to characterize the transcriptional and protein signatures of the small intestinal mucosa of naïve adult mice. Those data were validated by immunohistochemistry and quantitative ELISA using both small intestinal tissue lysates and serum. We identified a B-lymphocyte defect as a major transcriptional signature in the small intestinal mucosa and immunoglobulin A as the most downregulated protein by proteomic analysis in mice. Small intestinal immunoglobulins were dramatically dysregulated, with undetectable levels of immunoglobulin A and greatly increased amounts of immunoglobulin M being detected. The numbers of IgA-producing, cluster of differentiation (CD)138-positive plasma cells were also reduced in the lamina propria of the small intestinal villi of mice. This phenotype was even more striking in the small intestinal mucosa of mice, although these mice were equally sensitive to LPS-induced intestinal apoptosis as their wild-type counterparts. NF-κB2/p52 deficiency confers resistance to LPS-induced small intestinal apoptosis and also appears to regulate the plasma cell population and immunoglobulin levels within the gut. Novel transcriptomic analysis of murine proximal intestinal mucosa revealed an unexpected B cell signature in mice. In-depth analysis revealed a defect in the CD38+ B cell population and a gut-specific dysregulation of immunoglobulin levels.
非经典核因子-κB（NF-κB）信号通路主要调节 p52/RelB 异二聚体的功能。小鼠的 NF-κB2 基因缺失导致 p100/p52 蛋白缺失，并对多种胃肠道疾病提供保护，包括氧化偶氮甲烷/葡聚糖硫酸钠（DSS）诱导的结肠炎相关癌症和脂多糖（LPS）诱导的小肠上皮细胞凋亡。然而，共同的潜在保护机制尚未完全阐明。我们应用高通量 RNA-Seq 和蛋白质组学分析来描述幼稚成年小鼠的小肠黏膜的转录和蛋白质特征。这些数据通过免疫组织化学和使用小肠组织裂解物和血清的定量 ELISA 进行验证。我们发现 B 淋巴细胞缺陷是小肠黏膜的主要转录特征，免疫球蛋白 A 是蛋白质组学分析中 小鼠下调最明显的蛋白质。小肠免疫球蛋白明显失调，免疫球蛋白 A 水平无法检测到，免疫球蛋白 M 水平大大增加。在 小鼠的小肠绒毛固有层中，产生 IgA 的 CD138 阳性浆细胞的数量也减少了。尽管这些小鼠与它们的野生型对应物一样容易受到 LPS 诱导的肠道凋亡，但在 小鼠的小肠黏膜中这种表型更为明显。NF-κB2/p52 缺失赋予对 LPS 诱导的小肠凋亡的抗性，并且似乎还调节肠道内的浆细胞群体和免疫球蛋白水平。对小鼠近端小肠黏膜的新型转录组分析揭示了 小鼠中出乎意料的 B 细胞特征。深入分析显示 CD38+B 细胞群体存在缺陷，并且免疫球蛋白水平在肠道中特异性失调。
