Endocannabinoids signaling: Molecular mechanisms of liver regulation and diseases

The endocannabinoid system (ECS) includes endocannabinoids (eCBs), cannabinoid (CB) receptors and the enzymes that are responsible for endocannabinoid production and metabolism. The ECS has been reported to be present in both brain and peripheral tissues. Recent studies have indicated that eCBs and their receptors are involved in the development of various liver diseases. They were found to be altered in response to many danger factors. It is generally accepted that eCB may exert a protective action via CB2 receptors in different liver diseases. However, eCBs have also been demonstrated to have pathogenic role via their CB1 receptors. Although the therapeutic potential of CB1 receptor blockade in liver diseases is limited by its neuropsychiatric side effects, many studies have been conducted to search for novel, peripherally restricted CB1 antagonists or CB2 agonists, which may minimize their neuropsychiatric side effects in clinical use. This review summarizes the current understanding of the ECS in liver diseases and provides evidence for the potential to develop new therapeutic strategies for the treatment of these liver diseases.