NLRP3 炎性小体和 IL-1β 的激活在慢性病毒性肝炎症发病机制中的作用。
The role of the NLRP3 inflammasome and the activation of IL-1β in the pathogenesis of chronic viral hepatic inflammation.
机构信息
Department of Immunology and Histocompatibility, University of Thessaly, School of Health Sciences, Faculty of Medicine, Biopolis 41110, Larissa, Greece.
Molecular Virology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece; Molecular Biology and Immunobiotechnology Laboratory, Hellenic Pasteur Institute, 11521 Athens, Greece.
出版信息
Cytokine. 2018 Oct;110:389-396. doi: 10.1016/j.cyto.2018.04.032. Epub 2018 May 24.
BACKGROUND AND AIMS
Chronic viral hepatitis is a prevalent disease with major health implications. Its underlying pathophysiological mechanisms are not fully understood. IL-1β and the NLRP3 inflammasome involvement has been suggested in recent years, from in vitro data and data from peripheral blood samples. Therefore, we investigated IL-1β and the NLRP3 inflammasome in liver tissues in an effort to clarify their role in the pathophysiology of chronic viral hepatitis.
METHODS
We studied liver biopsies from patients with a new diagnosis of either chronic hepatitis B (CHB) and chronic hepatitis C (CHC) or patients with chronic hepatitis B in remission (CHB-rem). The biopsies were separated in two parts. The first part was sent to histology to determine the grade of inflammation and fibrosis. From the second part, RNA was extracted and converted to cDNA used in semi-quantitative Real-Time PCR to measure the levels of IL1B, CASP1, NLRP3, ASC and IL1RA. The cell lines used in the in vitro experiments were Huh7.5, LX2 and THP-1 in variety of combinations of monocultures, co-cultures and triple cultures with one of the cell lines infected with the JFH-1 HCV clone. From the cell cultures RNA was extracted and converted to cDNA. For cell lines, we focused in the expression of IL1B and NLRP3.
RESULTS
The expression of IL1B, CASP1 and NLRP3 were found significantly different between our groups (p = 0.001, p = 0.001 and p = 0.038, respectively). CHB patients displayed significantly higher IL1B and CASP1 mRNA levels compared to both CHB-rem and CHC patients. IL1B expression significantly correlates with liver biochemical data in CHB patients (AST: p = 0.006, r = 0.457; ALT p = 0.002, r = 0.497). Finally, mRNA levels of IL1B in CHB patients significantly correlate with the degree of inflammation (p = 0.016) but not the stage of fibrosis (p = 0.362). Interestingly, the relative expression of IL1B in triple culture experiments in vitro was below of 1.5-fold, suggesting no activation of IL1B. Moreover, no activation of NLRP3 was demonstrated in all investigated in vitro conditions.
CONCLUSION
IL-1β might play an important role in the pathogenesis of chronic hepatic inflammation from HBV, but not from HCV.
背景与目的
慢性病毒性肝炎是一种常见疾病，对健康有重大影响。其潜在的病理生理机制尚未完全了解。近年来，从体外数据和外周血样本数据中发现白细胞介素 1β（IL-1β）和 NLRP3 炎性小体参与其中。因此，我们研究了肝组织中的 IL-1β 和 NLRP3 炎性小体，以阐明它们在慢性病毒性肝炎病理生理学中的作用。
方法
我们研究了新诊断为慢性乙型肝炎（CHB）和慢性丙型肝炎（CHC）或慢性乙型肝炎缓解（CHB-rem）的患者的肝活检组织。将活检组织分为两部分。第一部分用于组织学检查，以确定炎症和纤维化程度。从第二部分提取 RNA 并转化为 cDNA，用于半定量实时 PCR 测量 IL1B、CASP1、NLRP3、ASC 和 IL1RA 的水平。体外实验中使用的细胞系为 Huh7.5、LX2 和 THP-1，以多种方式进行单核培养、共培养和三细胞培养，其中一种细胞系感染了 JFH-1 HCV 克隆。从细胞培养物中提取 RNA 并转化为 cDNA。对于细胞系，我们主要关注 IL1B 和 NLRP3 的表达。
结果
我们发现各组之间的 IL1B、CASP1 和 NLRP3 的表达存在显著差异（p=0.001、p=0.001 和 p=0.038）。与 CHB-rem 和 CHC 患者相比，CHB 患者的 IL1B 和 CASP1 mRNA 水平明显更高。IL1B 表达与 CHB 患者的肝生化数据显著相关（AST：p=0.006，r=0.457；ALT：p=0.002，r=0.497）。最后，CHB 患者的 IL1B mRNA 水平与炎症程度显著相关（p=0.016），但与纤维化程度无关（p=0.362）。有趣的是，体外三细胞培养实验中 IL1B 的相对表达低于 1.5 倍，表明 IL1B 未被激活。此外，在所有研究的体外条件下均未证明 NLRP3 的激活。
结论
IL-1β 可能在乙型肝炎引起的慢性肝炎症发病机制中发挥重要作用，但在丙型肝炎中则不然。
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