Song Yang-Da, Song Yi-Hang, Liu Si-Xue, Huang Hua-Rong, Zhong Ying-Qiang
Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.
Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institutes of Sun Yat-Sen University, Guangzhou, China.
Arch Med Sci. 2021 May 7;20(6):2022-2033. doi: 10.5114/aoms/127587. eCollection 2024.
CC chemokine receptor 5 (CCR5) and the NF-κB signaling pathway play important roles in the pathophysiology of inflammatory bowel disease (IBD). Previously, we synthesized two peptides (GH and HY peptides) that specifically bind to the first and the second extracellular loops (ECL1 and ECL2, respectively) of CCR5 and preliminarily found an inhibitory effect of these peptides on colitis. However, the specific mechanism by which these two peptides regulate trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats remains unclear. Aim of the study was to further investigate the effect and mechanism of CCR5 binding peptides in rat colitis.
Experimental colitis was induced by 5% TNBS. CCR5 antagonist peptides were administered intravenously once a day for a week. Histological evaluation, real-time PCR, western blotting and correlation analysis were performed to examine the effects of the CCR5 binding peptides on the infiltration of inflammatory cells and the NF-κB signaling pathway.
Administration of GH and HY peptides ameliorated mucosal damage and reduced the infiltration of neutrophils, lymphocytes and macrophages in experimental colitis ( < 0.05). The expression of NF-κB-related genes, including p105, p100, IKK and TNF-α, was reduced after GH and HY peptide administration ( < 0.01), and the protein level of TNF-α and the phosphorylation of IKK, IκBα and p65 were also suppressed. Furthermore, the CCR5 antagonist peptides inhibited nuclear translocation of p65. Spearman correlation analysis showed that the infiltration of inflammatory cells was significantly correlated with the NF-κB pathway.
Antagonistic peptides that specifically bind to ECL1 and ECL2 of CCR5 inhibit the infiltration of neutrophils, lymphocytes and macrophages in the colonic mucosa of Sprague-Dawley rats with TNBS-induced colitis via regulation of the NF-κB signaling pathway.
C-C趋化因子受体5（CCR5）和核因子κB（NF-κB）信号通路在炎症性肠病（IBD）的病理生理学中发挥重要作用。此前，我们合成了两种分别特异性结合CCR5第一和第二细胞外环（分别为ECL1和ECL2）的肽（GH肽和HY肽），并初步发现这些肽对结肠炎有抑制作用。然而，这两种肽调节三硝基苯磺酸（TNBS）诱导的大鼠结肠炎的具体机制仍不清楚。本研究的目的是进一步探究CCR5结合肽在大鼠结肠炎中的作用及机制。
用5% TNBS诱导实验性结肠炎。CCR5拮抗剂肽每天静脉注射一次，持续一周。进行组织学评估、实时聚合酶链反应（PCR）、蛋白质印迹法及相关性分析，以检测CCR5结合肽对炎症细胞浸润和NF-κB信号通路的影响。
给予GH肽和HY肽可改善黏膜损伤，并减少实验性结肠炎中中性粒细胞、淋巴细胞和巨噬细胞的浸润（<0.05）。给予GH肽和HY肽后，NF-κB相关基因（包括p105、p100、IKK和TNF-α）的表达降低（<0.01），TNF-α的蛋白水平以及IKK、IκBα和p65的磷酸化也受到抑制。此外，CCR5拮抗剂肽抑制了p65的核转位。Spearman相关性分析表明，炎症细胞浸润与NF-κB通路显著相关。
特异性结合CCR于5的ECL1和ECL2的拮抗肽通过调节NF-κB信号通路，抑制TNBS诱导的Sprague-Dawley大鼠结肠黏膜中中性粒细胞、淋巴细胞和巨噬细胞的浸润。
