Research Article Details
| Article ID: | A21551 |
| PMID: | 25234945 |
| Source: | J Hepatol |
| Title: | Arginase 2 deficiency results in spontaneous steatohepatitis: a novel link between innate immune activation and hepatic de novo lipogenesis. |
| Abstract: | BACKGROUND & AIMS: Innate immune activation has been postulated as a central mechanism for disease progression from hepatic steatosis to steatohepatitis in obesity-related fatty liver disease. Arginase 2 competes with inducible nitric oxide synthase (iNOS) for its substrate and the balance between these two enzymes plays a crucial role in regulating immune responses and macrophage activation. Our aim was to test the hypothesis that arginase 2 deficiency in mice favours progression from isolated hepatic steatosis, induced by high fat feeding, to steatohepatitis. METHODS: Arginase 2-knockout (Arg2(-/-)) mice were studied for changes in liver histology and metabolic phenotype at baseline and after a short term course (7 week) feeding with a high fat (HFAT) diet. In additional experiments, Arg2(-/-) mice received tail vein injections of liposome-encapsulated clodronate (CLOD) over a three-week period to selectively deplete liver macrophages. RESULTS: Unexpectedly, Arg2(-/-) mice showed profound changes in their livers at baseline, characterized by significant steatosis as demonstrated with histological and biochemical analysis. These changes were independent of systemic metabolic parameters and associated with marked mRNA level increases of genes involved in hepatic de novo lipogenesis. Liver injury and inflammation were present with elevated serum ALT, marked infiltration of F4/80 positive cells, and increased mRNA levels of inflammatory genes. HFAT feeding exacerbated these changes. Macrophage depletion after CLOD injection significantly attenuated lipid deposition and normalized lipogenic mRNA profile of livers from Arg2(-/-) mice. CONCLUSIONS: This study identifies arginase 2 as a novel link between innate immune responses, hepatic lipid deposition, and liver injury. |
| DOI: | 10.1016/j.jhep.2014.09.015 |
| Strategy ID | Therapy Strategy | Synonyms | Therapy Targets | Therapy Drugs | |
|---|---|---|---|---|---|
| S02 | Enhance lipid metabolism | triglyceride-lowering; lipid tolerance; lipid metabolism | 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) inhibitor; Decreases intestinal cholesterol absorption; FXR agonist; ACC inhibitor; FAS inhibitor; DGAT2 inhibitor; SCD-1 inhibitor | Atorvastatin; Ezetimibe; Obeticholic Acid; GS-9674; GS-0976; TVB-2640; IONIS-DGAT2rx; Aramchol; | Details |
| S03 | Anti-fibrosis | fibrosis | Angiotensin Receptor Blocker (ARB); CCR2/CCR5 antagonist; Thyroid receptor β agonist; PEGylated human FGF21 analogue; Monoclonal antibody to lysyl oxidase-like 2 (LOXL2); Galectin-3 inhibitor; FGF19 variant | Losartan; Cenicriviroc; VK-2809; MGL-3196; Pegbelfermin; Simtuzumab; GR-MD-02; NGM282 | Details |
| S05 | Anti-inflammatory | inflammatory | Bile acid; TNF-a inhibitor; Dual PPAR-α and -δ agonists; Toll-Like Receptor; (TLR)-4 antagonist; Caspase inhibitor; ASK-1 inhibitor | Ursodeoxycholic Acid; Pentoxifylline; Elafibranor; JKB-121; Emricasan; Selonsertib; | Details |
| S07 | Anti-lipogenesis | de novo lipogenesis; de novo lipogenesis; DNL; anti-lipogenic mechanisms; adipogenesis; anti-obesity | stearoyl-CoA desaturase 1 (SCD-1); Acetyl-coenzyme carboxylase; acyl-CoA carboxylase inhibitor (ACC inhibitor); stearoyl Coenzyme A desaturase inhibitor (SCD inhibitor); THR-beta selective agonist; DGAT2 inhibitor; FASN inhibitor | Aramchol; Firsocostat (GS-0976); VK-2809; ION 224 | Details |
| Diseases ID | DO ID | Disease Name | Definition | Class | |
|---|---|---|---|---|---|
| I14 | 9970 | Obesity | An overnutrition that is characterized by excess body fat, traditionally defined as an elevated ratio of weight to height (specifically 30 kilograms per meter squared), has_material_basis_in a multifactorial etiology related to excess nutrition intake, decreased caloric utilization, and genetic susceptibility, and possibly medications and certain disorders of metabolism, endocrine function, and mental illness. https://en.wikipedia.org/wiki/Obesity | disease of metabolism/acquired metabolic disease/ nutrition disease/overnutrition | Details |