茶酚抑素通过M1巨噬细胞而非肠道菌群抑制小鼠结肠炎模型中肠道炎症反应的再激活
Title：
Reactivation of intestinal inflammation is suppressed by Catestatin in a murine model of colitis via M1 macrophages and not the gut microbiota
Abstract：
While there is growing awareness of a relationship between chromogranin-A (CHGA) and susceptibility to inflammatory conditions, the role of human catestatin [(hCTS); CHGA352–67] in the natural history of established inflammatory bowel disease is not known. Recently, using two different experimental models, we demonstrated that hCTS-treated mice develop less severe acute colitis. We have also shown the implication of the macrophages in this effect. The aims of this study were to determine (1) whether hCTS treatment could attenuate the reactivation of inflammation in adult mice with previously established chronic colitis; (2) whether this effect is mediated through macrophages or the gut microbiota. Quiescent colitis was induced in 7–8-week-old C57BL6 mice using four cycles (2–4%) of dextran sulfate sodium. hCTS (1.5 mg/kg/day) treatment or vehicle started 2 days before the last induction of colitis and continuing for 7 days. At sacrifice, macro- and microscopic scores were determined. Colonic pro-inflammatory cytokines [interleukin (IL)-6, IL-1β, and TNF- α], anti-inflammatory cytokines (IL-10, TGF- β), classically activated (M1) (iNOS, Mcp1), and alternatively activated (M2) (Ym1, Arg1) macrophages markers were studied using ELISA and/or RT-qPCR. In vitro, peritoneal macrophages isolated from naïve mice and treated with hCTS (10−5 M, 12 h) were exposed to either lipopolysaccharide (100 ng/ml, 12 h) to polarize M1 macrophages or to IL-4/IL-13 (20 ng/ml) to polarize M2 macrophages. M1/M2 macrophage markers along with cytokine gene expression were determined using RT-qPCR. Feces and mucosa-associated microbiota (MAM) samples were collected, and the V4 region of 16 s rRNA was sequenced. Micro- and macroscopic scores, colonic IL-6, IL-1β, TNF- α, and M1 macrophages markers were significantly decreased in the hCTS-treated group. Treatment did not have any effect on colonic IL-10, TGF-β, and M2 markers nor modified the bacterial richness, diversity, or the major phyla in colitic fecal and MAM samples. In vitro, pro-inflammatory cytokines levels, as well as their gene expression, were significantly reduced in hCTS-treated M1 macrophages. hCTS treatment did not affect M2 macrophage markers. These findings suggest that hCTS treatment attenuates the severity of inflammatory relapse through the modulation of the M1 macrophages and the release of pro-inflammatory cytokines.
All Authors：
Mohammad F Rabbi, Nour Eissa, Peris M Munyaka , Laëtitia Kermarrec , Omar Elgazzar , Ehsan Khafipour , Charles N Bernstein, Jean Eric Ghia
First Authors：
Mohammad F Rabbi
Correspondence：
Jean Eric Ghia
内容要点：
1、 嗜铬粒蛋白-A（CHGA）与炎症相关，但来源于CHGA的儿茶酚抑素在IBD中的作用未知；
2、 采用两种炎症模型，体内外实验证实儿茶酚抑素对小鼠肠道炎症反应的作用；3、 儿茶酚抑素处理组促炎因子IL-6，IL-1β，TNF- α，和M1型巨噬细胞标记物显著降低，而抗炎因子IL-10，TGF-β和M2型巨噬细胞标记物无变化；
4、 对小鼠粪便和粘膜样品的菌群丰度、多样性、门的种类无影响；
5、 儿茶酚抑素通过调节M1巨噬细胞和促进促炎细胞因子释放来减轻炎症复发的程度。