1. Academic Validation
  2. Immune response gene 1 deficiency aggravates high fat diet-induced nonalcoholic fatty liver disease via promotion of redox-sensitive AKT suppression

Immune response gene 1 deficiency aggravates high fat diet-induced nonalcoholic fatty liver disease via promotion of redox-sensitive AKT suppression

  • Biochim Biophys Acta Mol Basis Dis. 2023 Jan 24;166656. doi: 10.1016/j.bbadis.2023.166656.
Xue Zhang 1 Ying Zhi 2 Xinyan Zan 2 Kerui Fan 2 Kun Chen 2 Shuang Zhao 2 Xinyi Dai 2 Longjiang Li 2 Yongqiang Yang 2 Kai Hu 3 Xianqiong Gong 4 Li Zhang 5
Affiliations

Affiliations

  • 1 Department of Pathophysiology, Basic Medical College, Chongqing Medical University, Chongqing, China; Laboratory of Stem cell and Tissue Engineering, Chongqing Medical University, Chongqing, China.
  • 2 Department of Pathophysiology, Basic Medical College, Chongqing Medical University, Chongqing, China.
  • 3 Laboratory of Stem cell and Tissue Engineering, Chongqing Medical University, Chongqing, China.
  • 4 Hepatology Center, Xiamen Hospital of Traditional Chinese Medicine, Xiamen, Fujian Province, China. Electronic address: xianqiong-gong@hotmail.com.
  • 5 Department of Pathophysiology, Basic Medical College, Chongqing Medical University, Chongqing, China. Electronic address: zhangli@cqmu.edu.cn.
Abstract

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder worldwide. Immune response gene 1 (IRG1) catalyzes the production of bio-active itaconate, which is actively involved in the regulation of signal transduction. A recent study has found that the expression of IRG1 was significantly down-regulated in obesity-associated fatty liver, but the potential roles of IRG1 in the development NAFLD remain unclear. The present study found that genetic deletion of IRG1 aggravated high fat diet (HFD)-induced metabolic disturbance, including obesity, dyslipidemia and Insulin resistance. In addition, HFD induced more severe liver steatosis and higher serum ALT and AST level in IRG1 KO mice, which were accompanied with altered expression of genes involved in lipid uptake, synthesis and catabolism. RNA-seq and immunoblot analysis indicated that deficiency of IRG1 is associated with suppressed activation of Akt, a master metabolic regulator. Mechanistically, IRG1/itaconate enhanced the antioxidative NRF2 pathway and prevented redox-sensitive suppression of Akt. Interestingly, supplementation with 4-octyl itaconate (4-OI), a cell-permeable derivate of itaconate, alleviated HFD-induced oxidative stress, Akt suppression and liver steatosis. Therefore, IRG1 probably functions as a protective regulator in the development of NAFLD and the cell-permeable 4-OI might have potential value for the pharmacological intervention of NAFLD.

Keywords

AKT; Immune responsive gene 1; Itaconate; NRF2; Nonalcoholic fatty liver disease.

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