Sympathetic overdrive and unrestrained adipose lipolysis drive alcohol-induced hepatic steatosis in rodents

GDF15 links adipose tissue lipolysis with anxiety

Psychological stress changes both behaviour and metabolism to protect organisms. Adrenaline is an important driver of this response. Anxiety correlates with circulating free fatty acid levels and can be alleviated by a peripherally restricted β-blocker, suggesting a peripheral signal linking metabolism with behaviour. Here we show that adrenaline, the β3 agonist CL316,243 and acute restraint stress induce growth differentiation factor 15 (GDF15) secretion in white adipose tissue of mice. Genetic inhibition of adipose triglyceride lipase or genetic deletion of β-adrenergic receptors blocks β-adrenergic-induced increases in GDF15. Increases in circulating GDF15 require lipolysis-induced free fatty acid stimulation of M2-like macrophages within white adipose tissue. Anxiety-like behaviour elicited by adrenaline or restraint stress is eliminated in mice lacking the GDF15 receptor GFRAL. These data provide molecular insights into the mechanisms linking metabolism and behaviour and suggest that inhibition of GDF15-GFRAL signalling might reduce acute anxiety.

Puerarin Alleviates Alcoholic Liver Disease via Suppressing Lipolysis Induced by Sympathetic Outflow

The aim of this study was to evaluate the therapeutic effect of puerarin (PUE) on alcoholic liver disease (ALD) and elucidate the potential mechanism from the perspective of lipolysis and hepatic steatosis. Assessment of PUE efficacy against ALD was performed using serum biochemical parameters and the histological examination of liver and adipose tissue via Hematoxylin and eosin (H&E) staining. The potential mechanisms underlying the amelioration of ALD by PUE were investigated using Western blotting (WB) analysis and immunofluorescence (IHC) staining. We demonstrated that PUE attenuated steatosis in ALD by alleviating ethanol-induced liver damage and lipid accumulation, suppressing the expression of lipid synthesis genes, upregulating the expression of lipid metabolism genes, and reducing lipolysis by inhibiting adipose triglyceride lipase (ATGL) activation and the phosphorylation of hormone-sensitive lipase (HSL). In conclusion, PUE ameliorates ALD by inhibiting the sympathetic outflow-mediated activation of key lipolysis enzymes ATGL and HSL. These findings provide a solid theoretical foundation for the potential application of PUE in the clinical treatment of ALD.

The role of the nervous system in liver diseases

The nervous system significantly participates in maintaining homeostasis, and modulating repair and regeneration processes in the liver. Moreover, the nervous system also plays an important role in the processes associated with the development and progression of liver disease, and can either potentiate or inhibit these processes. The aim of this review is to describe the mechanisms and pathways through which the nervous system influences the development and progression of liver diseases, such as alcohol-associated liver disease, nonalcoholic fatty liver disease, cholestatic liver disease, hepatitis, cirrhosis, and hepatocellular carcinoma. Possible therapeutic implications based on modulation of signals transduction between the nervous system and the liver are also discussed.