Jin G, Yao X, Liu D, Zhang J, Zhang X, Yang Y, Bi Y, Zhang H, Dong G, Tang H, Cheng S, Hong F, Si M. Inducible nitric oxide synthase accelerates nonalcoholic fatty liver disease progression by regulating macrophage autophagy.
Immun Inflamm Dis 2023;
11:e1114. [PMID:
38156397 PMCID:
PMC10750437 DOI:
10.1002/iid3.1114]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 10/21/2023] [Accepted: 12/05/2023] [Indexed: 12/30/2023] Open
Abstract
BACKGROUND
Cells and tissues, such as macrophages, express inducible nitric oxide synthase (INOS) after stimulation by certain factors. INOS helps mediate the macrophage inflammatory reaction, but few studies have explored how INOS affects macrophage function in nonalcoholic fatty liver disease (NAFLD).
OBJECTIVE
This study investigated the role of INOS-mediated macrophage activity in NAFLD.
METHODS
A high-fat diet was used to establish an NAFLD mouse model. After 12 weeks, blood was collected for immune cell and lipid analyses, and liver tissues were collected for pathological analyses with hematoxylin and eosin and Oil Red O staining. Peritoneal macrophages were extracted in situ, cultured in Dulbecco's modified Eagle's medium, and stimulated with palmitic acid to mimic in vivo conditions for further assays. Real-time polymerase chain reaction, western blot analysis, and immunofluorescence were used to verify the expression of target genes or proteins.
RESULTS
In the NAFLD model, INOS expression in macrophages increased, and INOS knockdown significantly decreased the number of macrophages. Pathological examinations confirmed that INOS knockdown slowed NAFLD progression and macrophage infiltration during inflammation. INOS knockdown also enhanced phagocytosis and lipid transport by macrophages, and increased the expression of autophagy-related molecules in macrophages, which improved the autophagy level, promoted apoptotic cell degradation, and maintained intracellular environment homeostasis.
CONCLUSIONS
These results indicate a correlation between INOS expression and macrophage function in NAFLD.
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