[Alcohol and the liver]

Comprehensive characterization of hepatocyte-derived extracellular vesicles identifies direct miRNA-based regulation of hepatic stellate cells and DAMP-based hepatic macrophage IL-1β and IL-17 upregulation in alcoholic hepatitis mice

Extracellular vesicles (EVs) have been growingly recognized as biomarkers and mediators of alcoholic liver disease (ALD) in human and mice. Here we characterized hepatocyte-derived EVs (HC-EVs) and their cargo for their biological functions in a novel murine model that closely resembles liver pathology observed in patients with alcoholic hepatitis (AH), the most severe spectrum of ALD. The numbers of circulating EVs and HC-EVs were significantly increased by 10-fold in AH mice compared with control mice. The miRNA (miR)-seq analysis detected 20 upregulated and 4 downregulated miRNAs (P < 0.001-0.05) in AH-HC-EVs. Treatment of murine primary hepatic stellate cells (HSCs) with AH-HC-EVs induced α-SMA (P < 0.05) and Col1a1 (P < 0.001). Smad7 and Nr1d2 genes, which were downregulated in HSCs from the AH mice, were predicted targets of 20 miRs upregulated in AH-HC-EVs. Among them were miR-27a and miR-181 which upon transfection in HSCs, indeed repressed Nr1d2, the quiescent HSC marker. AH-HC-EVs were also enriched with organelle proteins and mitochondrial DNA (10-fold, P < 0.05) and upregulated IL-1β and IL-17 production by hepatic macrophages (HMs) from AH mice in a TLR9-dependent manner. These results demonstrate HC-EV release is intensified in AH and suggest that AH-HC-EVs orchestrate liver fibrogenesis by directly targeting the quiescent HSC transcripts via a unique set of miRNAs and by amplifying HSC activation via DAMP-based induction of profibrogenic IL-1β and IL-17 by HMs. KEY MESSAGES: • Circulating EVs and HC-EVs were increased in AH mice compared with control mice • AH-HC-EVs were enriched in miRNAs, organelle proteins, and mitochondrial DNA • AH-HC-EVs increased cytokine production by AH-HMs in a TLR9-dependent manner.

Extracellular vesicles in non-alcoholic and alcoholic fatty liver diseases

Fatty liver diseases, non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD) are the most common causes of chronic liver disease around the world. NAFLD and ALD can progress towards a more severe form of the disease, including as non-alcoholic steatohepatitis (NASH) and alcoholic steatohepatitis (ASH). In both instances central pathogenic events include hepatocyte death, liver inflammation, pathological angiogenesis, and fibrosis, followed by cirrhosis and cancer. Over the last few years, extracellular vesicles (EVs) have been identified as effective cell-to-cell communicators that contain a cell- and stress-specific cargo from the cell of origin and are capable of transferring this cargo to a target or acceptor cell. In this review, we focus on the growing evidence supporting a role for EVs in the pathophysiology of NASH and ASH as well as their potential roles as targets for novel biomarkers for these conditions.

[The liver and Europe]

The past 30 years have been witnessing major progress in the knowledge and management of liver diseases. Approximately 29 million people in European Union suffer from chronic liver disease. However, liver diseases have been neglected by most European and national political and public health deciders. A number of measures should be implemented at the European and country levels: an efficient surveillance and data collection policy; broad information of the general population on the nature and importance of liver diseases and the means to diagnose and treat them; treatment and management policies; promotion of research on the causes, risk factors, prevention and management of liver diseases as well as on the most efficient interventions to reduce their incidence, prevalence, morbidity and mortality. The European Association for the Study of the Liver (EASL) has launched in 2006 an ambitious public policy and communication action in order to get recognition of liver diseases as a major cause of morbidity and mortality in Europe and push for appropriate measures. The future of hepatology as a specialty will depend on the success of this initiative.