DataSheet_1_Fecal Lcn-2 level is a sensitive biological indicator for gut dysbiosis and intestinal inflammation in multiple sclerosis.pdf

Multiple Sclerosis (MS) has been reported to be associated with intestinal inflammation and gut dysbiosis. To elucidate the underlying biology of MS-linked gut inflammation, we investigated gut infiltration of immune cells during the development of spontaneous experimental autoimmune encephalomyelitis (EAE) in humanized transgenic (Tg) mice expressing HLA-DR2a and human T cell receptor (TCR) specific for myelin basic protein peptide (MBP87-99)/HLA-DR2a complexes. Strikingly, we noted the simultaneous development of EAE and colitis, suggesting a link between autoimmune diseases of the central nervous system (CNS) and intestinal inflammation. Examination of the colon in these mice revealed the infiltration of MBP-specific Th17 cells as well as recruitment of neutrophils. Furthermore, we observed that fecal Lipocalin-2 (Lcn-2), a biomarker of intestinal inflammation, was significantly elevated and predominantly produced by the gut-infiltrating neutrophils. We then extended our findings to MS patients and demonstrate that their fecal Lcn-2 levels are significantly elevated compared to healthy donors (HDs). The elevation of fecal Lcn-2 levels correlated with reduced bacterial diversity and increased levels of other intestinal inflammation markers including neutrophil elastase and calprotectin. Of interest, bacteria thought to be beneficial for inflammatory bowel disease (IBD) such as Anaerobutyricum, Blautia, and Roseburia, were reduced in fecal Lcn-2-high MS patients. We also observed a decreasing trend in serum acetate (a short-chain fatty acid) levels in MS Lcn-2-high patients compared to HDs. Furthermore, a decrease in the relative abundance of Blautia massiliensis was significantly associated with a reduction of acetate in the serum of MS patients. This study suggests that gut infiltration of Th17 cells and recruitment of neutrophils are associated with the development of gut dysbiosis and intestinal inflammation, and that fecal Lcn-2 level is a sensitive biological indicator for gut dysbiosis in multiple sclerosis.

已有研究表明，多发性硬化（Multiple Sclerosis, MS）与肠道炎症及肠道菌群失调（gut dysbiosis）密切相关。为阐明MS相关肠道炎症的潜在生物学机制，本研究针对表达HLA-DR2a以及识别髓鞘碱性蛋白肽（myelin basic protein peptide, MBP87-99）/HLA-DR2a复合物的人类T细胞受体（T cell receptor, TCR）的人源化转基因（transgenic, Tg）小鼠，探究了自发性实验性自身免疫性脑脊髓炎（experimental autoimmune encephalomyelitis, EAE）发生过程中肠道的免疫细胞浸润情况。令人意外的是，我们观察到EAE与结肠炎（colitis）同时发生，这提示中枢神经系统（central nervous system, CNS）自身免疫病与肠道炎症之间存在关联。对这些小鼠结肠的检测结果显示，MBP特异性Th17细胞发生浸润，同时中性粒细胞发生募集。此外，我们发现作为肠道炎症生物标志物的粪便脂质运载蛋白-2（Lipocalin-2, Lcn-2）水平显著升高，且其主要由肠道浸润的中性粒细胞产生。随后我们将研究结果拓展至MS患者群体，结果显示，与健康对照者（healthy donors, HDs）相比，患者的粪便Lcn-2水平显著升高。粪便Lcn-2水平升高与细菌多样性降低以及其他肠道炎症标志物（包括中性粒细胞弹性蛋白酶和钙卫蛋白）水平升高呈显著相关。值得关注的是，在粪便Lcn-2水平升高的MS患者中，被认为对炎症性肠病（inflammatory bowel disease, IBD）有益的细菌属，如Anaerobutyricum、Blautia和Roseburia，其相对丰度显著降低。我们还观察到，与健康对照者相比，粪便Lcn-2水平升高的MS患者的血清乙酸盐（一种短链脂肪酸）水平呈下降趋势。此外，Blautia massiliensis相对丰度的降低与MS患者血清乙酸盐水平的降低显著相关。本研究表明，Th17细胞肠道浸润及中性粒细胞募集与肠道菌群失调及肠道炎症的发生密切相关，且粪便Lcn-2水平可作为MS患者肠道菌群失调的敏感生物学指标。