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  3. A new mechanism of obeticholic acid on NASH treatment by inhibiting NLRP3 inflammasome activation in macrophage

A new mechanism of obeticholic acid on NASH treatment by inhibiting NLRP3 inflammasome activation in macrophage

  • Metabolism. 2021 Jul;120:154797. doi: 10.1016/j.metabol.2021.154797.
Suling Huang 1,  Yanwei Wu 2,  Zhuohui Zhao 3,  Bing Wu 4,  Kai Sun 3,  Haoyu Wang 4,  Li Qin 1,  Fang Bai 4,  Ying Leng 5,  Wei Tang 6
Affiliations

Affiliations

  • 1 State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
  • 2 Laboratory of Anti-inflammation, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
  • 3 State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
  • 4 Laboratory of Anti-inflammation, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
  • 5 State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China. Electronic address: yleng@simm.ac.cn.
  • 6 Laboratory of Anti-inflammation, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China. Electronic address: tangwei@simm.ac.cn.
PMID: 33984334 DOI: 10.1016/j.metabol.2021.154797
Abstract

Objective: Obeticholic acid (OCA) has been proved to play potential therapeutic effect on nonalcoholic steatohepatitis (NASH). Up to now, the study of OCA on NLRP3 inflammasome activation in macrophage is still blank and merits great attention. Here, we aimed to better characterize the role and mechanism of OCA on NASH treatment focusing on NLRP3 inflammasome activation in macrophages.

Methods: The effects of OCA on inflammasome activation were investigated in BMDM, Kupffer cell, BMDC and LX2 cell. Preconditioned media from BMDM culture was used to treat primary hepatocytes to explore the effects of macrophage NLRP3 inflammasome activation on the function of hepatocytes. In vivo, high fat diet plus CCl4 (DIO + CCl4) induced murine NASH model and choline-deficient and amino acid-defined (CDA) diet-induced NASH mice were used to verify the inhibitory effect of OCA on inflammasome activation in liver macrophages and recapitulate its protective role on NASH progressing. To clear up the effect of OCA on macrophage is FXR dependent or not, FXR siRNA was introduced into BMDMs.

Results: OCA blockaded NLRP3 inflammasome in BMDMs by impacting on the activation stage and disrupting ASC oligomerization. Preconditioned supernatant from LPS + ATP treated BMDMs increased mRNA expression of lipogenic Enzymes and lipid content, whereas preconditioned supernatant from OCA treated BMDM blocked these effects in both normal and the FXR knockdown hepatocytes. In DIO + CCl4 mice, the population of inflammatory myeloid lineage cells in livers was decreased upon OCA treatment. Accordingly, the level of IL-1β and IL-18 in liver, the hepatic expression of ASC, pro-caspase-1 and active Caspase-1, the expression of Caspase 1 p20 in liver macrophages were also reduced. Similar results were obtained in CDA diet-fed mice. Furthermore, OCA maintained the inhibition on NLRP3 inflammasome activation in FXR knockdown BMDMs, suggesting FXR could be dispensable in this effect.

Conclusions: This finding brings up a new mechanism of OCA on NASH treatment, suggested by direct inhibition on NLRP3 inflammasome activation in macrophage, further suppression on inflammasome activation-elicited hepatic lipid accumulation, and contributing to the amelioration of NASH.

Keywords

FXR; Hepatic lipid accumulation; Macrophage; NASH; NLRP3 inflammasome.

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