Hepatic miR-192-3p reactivation alleviates steatosis by targeting glucocorticoid receptor

Zhangting Wang; Kai-Kei Miu; Xueyan Zhang; Angel Tsz-Yau Wan; Gang Lu; Hoi-Hung Cheung; Heung-Man Lee; Alice Pik-Shan Kong; Juliana Chung-Ngor Chan; Wai-Yee Chan

doi:10.1016/j.jhepr.2020.100179

Hepatic miR-192-3p reactivation alleviates steatosis by targeting glucocorticoid receptor

JHEP Rep. 2020 Sep 6;2(6):100179. doi: 10.1016/j.jhepr.2020.100179. eCollection 2020 Dec.

Authors

Zhangting Wang¹, Kai-Kei Miu¹, Xueyan Zhang^{1

2}, Angel Tsz-Yau Wan¹, Gang Lu¹, Hoi-Hung Cheung¹, Heung-Man Lee³, Alice Pik-Shan Kong^{3

4

5}, Juliana Chung-Ngor Chan^{3

4

5}, Wai-Yee Chan^{1

6}

Affiliations

¹ School of Biomedical Sciences, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
² Department of Gynecology, Women's Hospital, School of Medicine, Zhejiang University, Zhejiang, China.
³ Department of Medicine and Therapeutics, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China.
⁴ Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, Hong Kong Special Administrative Region, China.
⁵ Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong Special Administrative Region, China.
⁶ CUHK_GDL Advanced Institute for Regenerative Medicine, Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.

Abstract

Background & aims: The paradox of hepatic insulin resistance describes the inability for liver to respond to bioenergetics hormones in suppressing gluconeogenesis whilst maintaining lipid synthesis. Here, we report the deficiency of miR-192-3p in the livers of mice with diabetes and its role in alleviating hepatic steatosis.

Methods: As conventional pre-microRNA (miRNA) stem-loop overexpression only boosts guiding strand (i.e. miR-192-5p) expression, we adopted an artificial AAV(DJ)-directed, RNA Pol III promoter-driven miRNA hairpin construct for star-strand-specific overexpression in the liver. Liver steatosis and insulin resistance markers were evaluated in primary hepatocytes, mice with diabetes, and mice with excessive carbohydrate consumption.

Results: Functional loss of miR-192-3p in liver exacerbated hepatic micro-vesicular steatosis and insulin resistance in either mice with diabetes or wild-type mice with excessive fructose consumption. Liver-specific overexpression of miR-192-3p effectively halted hepatic steatosis and ameliorated insulin resistance in these mice models. Likewise, hepatocytes overexpressing miR-192-3p exhibited improved lipid accumulation, accompanied with decreases in lipogenesis and lipid-accumulation-related transcripts. Mechanistically, glucocorticoid receptor (GCR, also known as nuclear receptor subfamily 3, group C, member 1 [NR3C1]) was demonstrated to be negatively regulated by miR-192-3p. The effect of miR-192-3p on mitigating micro-vesicular steatosis was ablated by the reactivation of NR3C1.

Conclusions: The star strand miR-192-3p was an undermined glycerolipid regulator involved in controlling fat accumulation and insulin sensitivity in liver through blockade of hepatic GCR signalling; this miRNA may serve as a potential therapeutic option for the common co-mobility of diabetic mellitus and fatty liver disease.

Lay summary: The potential regulatory activity of star strand microRNA (miRNA) species has been substantially underestimated. In this study, we investigate the role and mechanism of an overlooked star strand miRNA (miR-192-3p) in regulating hepatic steatosis and insulin signalling in the livers of mice with diabetes and mice under excessive carbohydrate consumption.

Keywords: 3′-UTR, 3′-untranslated region; AAV, adeno-associated virus; CPT, carnitine palmitoyl transferase; DEG, differentially expressed gene; DEX, dexamethasone; DM, diabetes mellitus; DNL, de novo lipogenesis; Diabetes mellitus; FA, fatty acid; FAO, fatty acid oxidation; FASN, fatty acid synthase; GCR, glucocorticoid receptor; Glucocorticoid receptor; HFD, high-fat diet; HFrD, high-fructose drink; HOMA-IR, homeostatic model assessment of insulin resistance; Hepatic steatosis; High carbohydrate consumption; MicroRNA; NAFLD, non-alcoholic fatty liver disease; NR3C1, nuclear receptor subfamily 3, group C, member 1; NT, non-targeting; OA, oleic acid; OGTT, oral glucose tolerance test; SCD1, stearoyl-CoA desaturase-1; T2DM, type 2 diabetes mellitus; TAG, triacylglyceride/triglyceride; Transcription repressor; VAT, visceral adipose tissue; miRNA, microRNA; shRNA, short hairpin RNA.