Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
Department of Hepatobiliary Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
Inflammation. 2017 Dec;40(6):1875-1883. doi: 10.1007/s10753-017-0628-z.
The cleavage and secretion of pro-inflammatory cytokines IL-1β and IL-18 is regulated by NLRP3 (NACHT, LRR, and PYD domain-containing protein 3) inflammasome activation. Kupffer cells (KCs) are implicated in the pathogenesis of various liver diseases, such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease, and liver fibrosis. However, the role of NLRP3 played in the non-alcoholic steatohepatitis (NASH) has yet to be evaluated. In the present study, methionine-choline-deficient (MCD) diet was used to establish the mice NASH model. The expression levels of F4/80 and NLRP3 in liver tissues were evaluated, and the IL-1β and IL-18 in serum were also evaluated. KCs were isolated from wild-type (WT) mice and NLRP3 knockout (NLRP3) mice and then randomly divided into two groups: the control and palmitic acid (PA) groups. The expression levels of NLRP3, ASC, and caspase-1 in KCs were determined by RT-PCR, western blotting, and immunofluorescence. The levels of IL-1β and IL-18 in the supernatant (SN) of KCs were evaluated by enzyme-linked immunosorbent assay (ELISA). We found that KCs and NLRP3 play pro-inflammatory roles in the progression of NASH, probably through secretions of IL-1β and IL-18 by KCs induced by PA. PA could act as a kind of damage-associated molecular patterns to elevate the messenger RNA and protein expression levels of NLRP3, ASC, and caspase-1 in KCs from WT mice. In the contrast, NLRP3 deletion could inhibit the NLRP3 inflammasome upregulation and activation in KCs induced by PA. Furthermore, the levels of pro-inflammatory cytokines IL-1β and IL-18 in the SN of KCs from WT mice were all elevated with the stimulation of PA, and the increase of these cytokines in the SN was blocked by NLRP3 deletion. In conclusion, our novel findings demonstrate that NLRP3 plays a pivotal role in NASH development and pro-inflammatory cytokines IL-1β and IL-18 secretion induced by PA stimulation, and NLRP3 might be an effective potential target for the treatment of liver inflammatory diseases associated with NLRP3 inflammasome activation.
促炎细胞因子白细胞介素-1β（IL-1β）和白细胞介素-18（IL-18）的切割和分泌受 NLRP3（NACHT、LRR 和 PYD 结构域包含蛋白 3）炎性小体激活的调节。Kupffer 细胞（KCs）参与了各种肝脏疾病的发病机制，如非酒精性脂肪性肝病（NAFLD）、酒精性肝病和肝纤维化。然而，NLRP3 在非酒精性脂肪性肝炎（NASH）中的作用尚未得到评估。在本研究中，使用蛋氨酸-胆碱缺乏（MCD）饮食建立了小鼠 NASH 模型。评估了肝组织中 F4/80 和 NLRP3 的表达水平，还评估了血清中 IL-1β 和 IL-18 的水平。从野生型（WT）小鼠和 NLRP3 敲除（NLRP3）小鼠中分离 KCs，并将其随机分为两组：对照组和棕榈酸（PA）组。通过 RT-PCR、western blot 和免疫荧光法测定 KCs 中 NLRP3、ASC 和 caspase-1 的表达水平。通过酶联免疫吸附试验（ELISA）测定 KCs 上清液（SN）中 IL-1β 和 IL-18 的水平。我们发现 KCs 和 NLRP3 在 NASH 的进展中发挥促炎作用，可能是通过 PA 诱导的 KCs 分泌 IL-1β 和 IL-18 引起的。PA 可以作为一种损伤相关分子模式，提高 WT 小鼠 KCs 中 NLRP3、ASC 和 caspase-1 的信使 RNA 和蛋白表达水平。相比之下，NLRP3 缺失可抑制 PA 诱导的 KCs 中 NLRP3 炎性小体的上调和激活。此外，PA 刺激可使 WT 小鼠 KCs SN 中促炎细胞因子 IL-1β 和 IL-18 的水平升高，NLRP3 缺失可阻断这些细胞因子在 SN 中的增加。总之，我们的新发现表明，NLRP3 在 NASH 的发展和 PA 刺激诱导的促炎细胞因子 IL-1β 和 IL-18 分泌中起关键作用，NLRP3 可能是治疗与 NLRP3 炎性小体激活相关的肝脏炎症性疾病的有效潜在靶点。
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