背景:非酒精性脂肪性肝炎(NASH),最严重的非酒精性脂肪性肝病(NAFLD),目前无法用临床验证的治疗方法治疗。基质金属肽酶10(MMP10)是参与免疫应答的常见宿主应答基因。然而,目前尚不清楚MMP10是否以及如何通过调节巨噬细胞功能影响NASH发育。
方法:体外,MMP10过表达(MMP10-OE),MMP10基因敲除(MMP10-KO),增殖物激活受体γ(PPARγ)-OE,和对照质粒被转染到原代枯否细胞中,然后在有或没有白细胞介素(IL)-4刺激的情况下培养。MMP10-OE小鼠和MMP10-KO小鼠饲喂正常饮食(NCD)或高脂饮食(HFD)30周以研究MMP10在NASH模型中的作用。Hepa1-6细胞在有或没有游离脂肪酸(FFA)处理的情况下培养24小时。
结果:MMP10在NASH中下调,和M1/M2指标明显失衡。MMP10响应于M2巨噬细胞极化而被触发。MMP10过表达减少HFD诱导的NASH中的肝脂肪变性和炎症。机械上,PPARγ可以与MMP10启动子结合,然后上调MMP10的表达,当IL-4刺激M2巨噬细胞极化时参与。下游STAT3信号通路被进一步激活,诱导M2极化,这导致促炎性IL-1β和肿瘤坏死因子(TNF)-a的表达降低和抗炎IL-10的表达增加,最终缓解NASH进展。
结论:我们证明IL-4通过PPARγ有效促进MMP10表达,MMP10过表达调节巨噬细胞极化,肝脂肪变性,和纤维化,为NASH治疗提供前瞻性目标。
BACKGROUND: Non-alcoholic steatohepatitis (NASH), the most severe form of non-alcoholic fatty liver disease (NAFLD), is currently untreatable with a clinically validated treatment. Matrix Metallopeptidase 10 (MMP10) is a common host-response-gene involved in the immune response. However, it remains unknown whether and how MMP10 influences NASH development by modulating macrophage function.
METHODS: In vitro,
MMP10 overexpression (
MMP10-OE),
MMP10 knockout (
MMP10-KO), proliferator-activated receptor γ (PPARγ)-OE, and control plasmids were transfected into primary Kupffer cells, which were then cultured with or without Interleukin (IL)-4 stimulation.
MMP10-OE mice and
MMP10-KO mice were fed a normal chow diet (NCD) or a high-fat diet (HFD) for 30 weeks to study the role of
MMP10 in NASH model. Hepa1-6 cells were cultured with or without free fatty acid (FFA) treatment for 24 h.
RESULTS: MMP10 is downregulated in NASH, and M1/M2 indicators are significantly imbalanced.
MMP10 is triggered in response to M2 macrophages polarization. MMP10 overexpression diminishes hepatic steatosis and inflammation in HFD-induced NASH. Mechanistically, PPARγ can bind to the
MMP10 promoter and then up-regulates
MMP10 expression, which is engaged when IL-4 stimulates M2 macrophage polarization. The downstream STAT3 signaling pathway is further activated to induce M2 polarization, which results in a decreased expression of the pro-inflammatory IL-1β and tumor necrosis factor (TNF)-a and an increased expression of the anti-inflammatory IL-10, ultimately alleviating NASH progression.
CONCLUSIONS: We demonstrate that IL-4 effectively promotes MMP10 expression via PPARγ, and MMP10 overexpression modulates macrophage polarization, hepatic steatosis, and fibrosis, offering prospective targets for NASH treatment.