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Liver fibrosis, a common scarring response to chronic liver injury, is a precursor to cirrhosis and liver cancer. Here, we identified signal transducer and activator of transcription 1 (STAT1) as an important negative regulator in liver fibrosis. Our findings show that disruption of the STAT1 gene accelerated liver fibrosis and hepatic stellate cell (HSC) proliferation in an in vivo model of carbon tetrachloride (CCl4)-induced liver fibrosis. In vitro treatment with IFN-gamma inhibited prolifera

Abstract Reactive oxygen species (ROS) contribute to the development of non-alcoholic fatty liver disease. ROS generation by infiltrating macrophages involves multiple mechanisms, including Toll-like receptor 4 (TLR4)-mediated NADPH oxidase (NOX) activation. Here, we show that palmitate-stimulated CD11b + F4/80 low hepatic infiltrating macrophages, but not CD11b + F4/80 high Kupffer cells, generate ROS via dynamin-mediated endocytosis of TLR4 and NOX2, independently from MyD88 and TRIF. We demon

UNLABELLED: During liver injury, hepatocytes secrete exosomes that include diverse types of self-RNAs. Recently, self-noncoding RNA has been recognized as an activator of Toll-like receptor 3 (TLR3). However, the roles of hepatic exosomes and TLR3 in liver fibrosis are not yet fully understood. Following acute liver injury and early-stage liver fibrosis induced by a single or 2-week injection of carbon tetrachloride (CCl4 ), increased interleukin (IL)-17A production was detected primarily in hep

UNLABELLED: Activation of innate immunity (natural killer [NK] cell/interferon-γ [IFN-γ]) has been shown to play an important role in antiviral and antitumor defenses as well as antifibrogenesis. However, little is known about the regulation of innate immunity during chronic liver injury. Here, we compared the functions of NK cells in early and advanced liver fibrosis induced by a 2-week or a 10-week carbon tetrachloride (CCl(4) ) challenge, respectively. Injection of polyinosinic-polycytidylic

Quiescent hepatic stellate cells (HSCs) in healthy liver store 80% of total liver retinols and release them depending on the extracellular retinol status. However, HSCs activated by liver injury lose their retinols and produce a considerable amount of extracellular matrix, subsequently leading to liver fibrosis. Emerging evidence suggests that retinols and their metabolites such as retinoic acids (RAs) contribute to liver regeneration, fibrosis and tumor. However, it is not clear yet why HSCs lo

Background and Aims Mitochondrial double‐stranded RNA (mtdsRNA) and its innate immune responses have been reported previously; however, mtdsRNA generation and its effects on alcohol‐associated liver disease (ALD) remain unclear. Here, we report that hepatic mtdsRNA stimulates toll‐like receptor 3 (TLR3) in Kupffer cells through the exosome (Exo) to enhance interleukin (IL)‐17A (IL‐17A) production in ALD. Approach and Results Following binge ethanol (EtOH) drinking, IL‐17A production primarily in

To date, the majority of research on hypercholesterolemia has focused on the effects of a high cholesterol diet on atherosclerosis and coronary heart disease. The toxic effects of cholesterol on the liver and the relationship between the intake of a high cholesterol diet and hepatic fibrosis, however, have not been investigated clearly or histopathologically. Male Wistar rats were fed a diet supplemented with 1.0% cholesterol and 0.3% sodium cholate for 12 weeks. Rats were sacrificed and analyze

UNLABELLED: Clinical trials and animal models suggest that infusion of bone marrow cells (BMCs) is effective therapy for liver fibrosis, but the underlying mechanisms are obscure, especially those associated with early effects of BMCs. Here, we analyzed the early impact of BMC infusion and identified the subsets of BMCs showing antifibrotic effects in mice with carbon tetrachloride-induced liver fibrosis. An interaction between BMCs and activated hepatic stellate cells (HSCs) was investigated us

The hepatic innate immune system consists of predominant innate immunity, which plays an important role in innate defense against infection and tumor transformation. Emerging evidence suggests that innate immunity also contributes to liver injury, repair, and fibrosis. The present review summarizes the recent findings on the role of innate immunity in liver fibrosis. In general, Kupffer cells stimulate liver fibrosis via production of reactive oxygen species and pro-inflammatory cytokines, where

Background and Aims The important roles of glutamate and metabotropic glutamate receptor 5 (mGluR5) in HSCs have recently been reported in various liver diseases; however, the mechanism linking the glutamine/glutamate metabolism and mGluR5 in liver fibrosis remains unclear. Here, we report that mGluR5 activation in natural killer (NK) cells attenuates liver fibrosis through increased cytotoxicity and interferon‐γ (IFN‐γ) production in both mice and humans. Approach and Results Following 2‐week i

Activated hepatic stellate cells (HSCs) have been considered as a major type of cells in liver fibrosis by producing a huge amount of extracellular matrix, especially collagen fibers, and profibrotic mediators such as transforming growth factor-beta, interleukin-6 and monocyte chemoattractant protein-1. Recently, accumulated evidence suggests that the liver is an immunologic organ because of enrichment of diverse types of immune cells and that their interactions with HSCs are closely related wit