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Kakiyama G, Marques D, Martin R, Takei H, Rodriguez-Agudo D, LaSalle SA, Hashiguchi T, Liu X, Green R, Erickson S, Gil G, Fuchs M, Suzuki M, Murai T, Nittono H, Hylemon PB, Zhou H, Pandak WM. Insulin resistance dysregulates CYP7B1 leading to oxysterol accumulation: a pathway for NAFL to NASH transition. J Lipid Res 2020; 61:1629-1644. [PMID: 33008924 PMCID: PMC7707165 DOI: 10.1194/jlr.ra120000924] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
NAFLD is an important public health issue closely associated with the pervasive epidemics of diabetes and obesity. Yet, despite NAFLD being among the most common of chronic liver diseases, the biological factors responsible for its transition from benign nonalcoholic fatty liver (NAFL) to NASH remain unclear. This lack of knowledge leads to a decreased ability to find relevant animal models, predict disease progression, or develop clinical treatments. In the current study, we used multiple mouse models of NAFLD, human correlation data, and selective gene overexpression of steroidogenic acute regulatory protein (StarD1) in mice to elucidate a plausible mechanistic pathway for promoting the transition from NAFL to NASH. We show that oxysterol 7α-hydroxylase (CYP7B1) controls the levels of intracellular regulatory oxysterols generated by the "acidic/alternative" pathway of cholesterol metabolism. Specifically, we report data showing that an inability to upregulate CYP7B1, in the setting of insulin resistance, results in the accumulation of toxic intracellular cholesterol metabolites that promote inflammation and hepatocyte injury. This metabolic pathway, initiated and exacerbated by insulin resistance, offers insight into approaches for the treatment of NAFLD.
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Affiliation(s)
- Genta Kakiyama
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA.
| | - Dalila Marques
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | - Rebecca Martin
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - Hajime Takei
- Junshin Clinic Bile Acid Institute, Tokyo, Japan
| | - Daniel Rodriguez-Agudo
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | - Sandra A LaSalle
- Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | | | - Xiaoying Liu
- Department of Medicine, Northwestern University, Chicago, IL, USA
| | - Richard Green
- Department of Medicine, Northwestern University, Chicago, IL, USA
| | - Sandra Erickson
- School of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Gregorio Gil
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Michael Fuchs
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA
| | - Mitsuyoshi Suzuki
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Tsuyoshi Murai
- School of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Hokkaido, Japan
| | | | - Phillip B Hylemon
- Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - Huiping Zhou
- Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
| | - William M Pandak
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, USA; Department of Veterans Affairs, McGuire Veterans Administration Medical Center, Richmond, VA, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
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