Chonwerawong Michelle, Ferrand Jonathan, Chaudhry Hassan Mohammad, Higgins Chloe, Tran Le Son, Lim San Sui, Walker Marjorie M, Bhathal Prithi S, Dev Anouk, Moore Gregory T, Sievert William, Jenkins Brendan J, D'Elios Mario M, Philpott Dana J, Kufer Thomas A, Ferrero Richard L
Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Victoria, Australia; Department of Molecular and Translational Science, Monash University, Victoria, Australia.
Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Victoria, Australia.
Gastroenterology. 2020 Jul;159(1):169-182.e8. doi: 10.1053/j.gastro.2020.03.009. Epub 2020 Mar 10.
BACKGROUND & AIMS: Helicobacter pylori induces strong inflammatory responses that are directed at clearing the infection, but if not controlled, these responses can be harmful to the host. We investigated the immune-regulatory effects of the innate immune molecule, nucleotide-binding oligomerization domain-like receptors (NLR) family CARD domain-containing 5 (NLRC5), in patients and mice with Helicobacter infection.
We obtained gastric biopsies from 30 patients in Australia. We performed studies with mice that lack NLRC5 in the myeloid linage (Nlrc5) and mice without Nlrc5 gene disruption (controls). Some mice were gavaged with H pylori SS1 or Helicobacter felis; 3 months later, stomachs, spleens, and sera were collected, along with macrophages derived from bone marrow. Human and mouse gastric tissues and mouse macrophages were analyzed by histology, immunohistochemistry, immunoblots, and quantitative polymerase chain reaction. THP-1 cells (human macrophages, controls) and NLRC5 THP-1 cells (generated by CRISPR-Cas9 gene editing) were incubated with Helicobacter and gene expression and production of cytokines were analyzed.
Levels of NLRC5 messenger RNA were significantly increased in gastric tissues from patients with H pylori infection, compared with patients without infection (P < .01), and correlated with gastritis severity (P < .05). H pylori bacteria induced significantly higher levels of chemokine and cytokine production by NLRC5 THP-1 macrophages than by control THP-1 cells (P < .05). After 3 months of infection with H felis, Nlrc5 mice developed gastric hyperplasia (P < .0001), splenomegaly (P < .0001), and increased serum antibody titers (P < .01), whereas control mice did not. Nlrc5 mice with chronic H felis infection had increased numbers of gastric B-cell follicles expressing CD19 (P < .0001); these follicles had features of mucosa-associated lymphoid tissue lymphoma. We identified B-cell-activating factor as a protein that promoted B-cell hyperproliferation in Nlrc5 mice.
NLRC5 is a negative regulator of gastric inflammation and mucosal lymphoid formation in response to Helicobacter infection. Aberrant NLRC5 signaling in macrophages can promote B-cell lymphomagenesis during chronic Helicobacter infection.
幽门螺杆菌会引发强烈的炎症反应，旨在清除感染，但如果这些反应得不到控制，可能会对宿主造成伤害。我们研究了天然免疫分子含核苷酸结合寡聚化结构域样受体（NLR）家族CARD结构域蛋白5（NLRC5）在幽门螺杆菌感染患者和小鼠中的免疫调节作用。
我们从澳大利亚的30名患者身上获取了胃活检组织。我们对髓系谱系中缺乏NLRC5的小鼠（Nlrc5）和未进行Nlrc5基因敲除的小鼠（对照）进行了研究。部分小鼠经口灌喂幽门螺杆菌SS1或猫幽门螺杆菌；3个月后，收集胃、脾脏和血清，以及从骨髓中分离出的巨噬细胞。通过组织学、免疫组织化学、免疫印迹和定量聚合酶链反应对人和小鼠的胃组织以及小鼠巨噬细胞进行分析。将THP-1细胞（人巨噬细胞，对照）和NLRC5 THP-1细胞（通过CRISPR-Cas9基因编辑产生）与幽门螺杆菌一起孵育，并分析基因表达和细胞因子的产生情况。
与未感染患者相比，幽门螺杆菌感染患者胃组织中NLRC5信使核糖核酸水平显著升高（P < 0.01），且与胃炎严重程度相关（P < 0.05）。幽门螺杆菌诱导NLRC5 THP-1巨噬细胞产生趋化因子和细胞因子的水平显著高于对照THP-1细胞（P < 0.05）。感染猫幽门螺杆菌3个月后，Nlrc5小鼠出现胃增生（P < 0.0001）、脾肿大（P < 0.0001），血清抗体滴度升高（P < 0.01），而对照小鼠未出现这些情况。慢性感染猫幽门螺杆菌的Nlrc5小鼠胃中表达CD19的B细胞滤泡数量增加（P < 0.0001）；这些滤泡具有黏膜相关淋巴组织淋巴瘤的特征。我们确定B细胞活化因子是一种促进Nlrc5小鼠B细胞过度增殖的蛋白。
NLRC5是幽门螺杆菌感染后胃炎症和黏膜淋巴组织形成的负调节因子。巨噬细胞中异常的NLRC5信号传导可在慢性幽门螺杆菌感染期间促进B细胞淋巴瘤的发生。
