School of Pre-clinical Medicine, Guangxi Medical University, Nanning, China.
Department of Immunology, Guangxi University of Chinese Medicine, Nanning, China.
PLoS Negl Trop Dis. 2022 Sep 9;16(9):e0010774. doi: 10.1371/journal.pntd.0010774. eCollection 2022 Sep.
Currently, inflammatory bowel disease (IBD) has become a global chronic idiopathic disease with ever-rising morbidity and prevalence. Accumulating evidence supports the IBD-hygiene hypothesis that helminths and their derivatives have potential therapeutic value for IBD. Clonorchis sinensis (C. sinensis) mainly elicit Th2/Treg-dominated immune responses to maintain long-term parasitism in the host. This study aimed to evaluate the therapeutic effects of cysteine protease (CsCP) and adult crude antigen (CsCA) of C. sinensis, and C. sinensis (Cs) infection on DSS-induced colitis mice.
BALB/c mice were given 5% DSS daily for 7 days to induce colitis. During this period, mice were treated with rCsCP, CsCA or dexamethasone (DXM) every day, or Cs infection which was established in advance. Changes in body weight, disease activity index (DAI), colon lengths, macroscopic scores, histopathological findings, myeloperoxidase (MPO) activity levels, regulatory T cell (Treg) subset levels, colon gene expression levels, serum cytokine levels, and biochemical indexes were measured.
Compared with Cs infection, rCsCP and CsCA alleviated the disease activity of acute colitis more significant without causing abnormal blood biochemical indexes. In comparison, rCsCP was superior to CsCA in attenuating colonic pathological symptoms, enhancing the proportion of Treg cells in spleens and mesenteric lymph nodes, and improving the secretion of inflammatory-related cytokines (e.g., IL-2, IL-4, IL-10 and IL-13) in serum. Combined with RNA-seq data, it was revealed that CsCA might up-regulate the genes related to C-type lectin receptor and intestinal mucosal repair related signal pathways (e.g., Cd209d, F13a1 and Cckbr) to reduce colon inflammation and benefit intestinal mucosal repair. Dissimilarly, rCsCP ameliorated colitis mainly through stimulating innate immunity, such as Toll like receptor (TLR) signaling pathway, down-regulating the expression of inflammatory cytokines (e.g., IL-12b, IL-23r and IL-7), thereby restraining the differentiation of Th1/Th17 cells.
Both rCsCP and CsCA showed good therapeutic effects on the treatment of acute colitis, but rCsCP is a better choice. rCsCP is a safe, effective, readily available and promising therapeutic agent against IBD mainly by activating innate immunity and regulating the IL-12/IL-23r axis.
目前，炎症性肠病（IBD）已成为一种全球慢性特发性疾病，发病率和患病率不断上升。越来越多的证据支持 IBD-卫生假说，即寄生虫及其衍生物对 IBD 具有潜在的治疗价值。华支睾吸虫（C. sinensis）主要诱导 Th2/Treg 为主的免疫反应，以维持在宿主中的长期寄生虫状态。本研究旨在评估华支睾吸虫的半胱氨酸蛋白酶（CsCP）和成虫粗抗原（CsCA）以及华支睾吸虫感染对 DSS 诱导的结肠炎小鼠的治疗作用。
BALB/c 小鼠每天给予 5% DSS 诱导结肠炎，共 7 天。在此期间，每天用 rCsCP、CsCA 或地塞米松（DXM）治疗，或预先建立华支睾吸虫感染。测量体重、疾病活动指数（DAI）、结肠长度、大体评分、组织病理学发现、髓过氧化物酶（MPO）活性水平、调节性 T 细胞（Treg）亚群水平、结肠基因表达水平、血清细胞因子水平和生化指标的变化。
与华支睾吸虫感染相比，rCsCP 和 CsCA 更显著地减轻了急性结肠炎的疾病活动度，而不会导致异常的血液生化指标。相比之下，rCsCP 在减轻结肠病理症状、增加脾脏和肠系膜淋巴结中 Treg 细胞的比例以及改善血清中炎症相关细胞因子（如 IL-2、IL-4、IL-10 和 IL-13）的分泌方面优于 CsCA。结合 RNA-seq 数据，结果表明 CsCA 可能通过上调 C 型凝集素受体和肠黏膜修复相关信号通路（如 Cd209d、F13a1 和 Cckbr）的相关基因，减轻结肠炎症，促进肠黏膜修复。相反，rCsCP 主要通过刺激先天免疫，如 Toll 样受体（TLR）信号通路，下调炎症细胞因子（如 IL-12b、IL-23r 和 IL-7）的表达，从而抑制 Th1/Th17 细胞的分化，来改善结肠炎。
rCsCP 和 CsCA 对急性结肠炎的治疗均有较好的疗效，但 rCsCP 是更好的选择。rCsCP 是一种安全、有效、易得且有前途的 IBD 治疗药物，主要通过激活先天免疫和调节 IL-12/IL-23r 轴发挥作用。
