ASK1 Enhances Angiotensin II-Induced Liver Fibrosis In Vitro by Mediating Endoplasmic Reticulum Stress-Dependent Exosomes.

BACKGROUND: Apoptosis signal-regulating kinase 1 (ASK1) has been reported to induce fibrotic signaling in the setting of oxidative stress. However, the role of ASK1 and its mechanism of action in angiotensin II- (Ang II-) induced liver fibrosis remain largely unknown. METHODS: Human hepatic LX-2 stellate cells were treated with Ang II alone or cotreated with Ang II plus an ASK1 inhibitor (GS-4997) or siRNA-targeting ASK1. Immunofluorescent staining, real-time PCR, and western blotting were used to determine the expressionof α-SMA, Col I, and Col III expression. Cell viability was assessed by the CCK-8 assay. The concentrations of IL-1ß, IL-18, and TNF-α in conditioned medium were determined by ELISA. The levels of intracellular ROS in LX-2 cells were analyzed using a ROS assay kit. Exosome size was determined by electron microscopy. RESULTS: Ang II markedly increased the expression of extracellular matrix (ECM) proteins (α-SMA, Col I, and Col III) and proinflammatory cytokines (IL-1ß, IL-18, and TNF-α). Ang II also increased the expression of endoplasmic reticulum stress (ERS) markers (GRP78, p-PERK, and CHOP) and p-ASK1. Results also showed that pretreatment with GS-4997 or siRNA could abolish all the abovementioned effects on LX-2 cells. Furthermore, we found that exosome release caused by ASK1-mediated ERS was involved in the activation of LX-2 cells by Ang II. The activation of LX-2 cells could be blocked by treating the exosomes with annexin. CONCLUSIONS: In summary, we found that ASK1 mediates Ang II-activated ERS in HSCs and the subsequent activation of HSCs, suggesting a promising strategy for treating liver fibrosis.

Analyzing hedyotis diffusa mechanisms of action from the genomics perspective.

BACKGROUND AND OBJECTIVE: Hedyotis diffusa is an herb used for anti-cancer, anti-oxidant, anti-inflammatory, and anti-fibroblast treatment in the clinical practice of Traditional Chinese Medicine. However, its pharmacological mechanisms have not been fully established and there is a lack of modern scientific verification. One of the best ways to further understand Hedyotis diffusa's mechanisms of action is to analyze it from the genomics perspective. METHODS: In this study, we used network pharmacology approaches to infer the herb-gene interactions, the herb-pathway interactions, and the gene families. We then analyzed Hedyotis diffusa's mechanisms of action using the genomics context combined with the Traditional Chinese Medicine clinical practice and the pharmacological research. RESULTS: The results obtained in the pathway and gene family analysis were consistent with the Traditional Chinese Medicine clinical experience and the pharmacological activities of Hedyotis diffusa. CONCLUSIONS: Our approach can identify related genes and pathways correctly with little a priori knowledge, and provide potential directions to facilitate further research.

Shikonin protects against D-Galactosamine and lipopolysaccharide-induced acute hepatic injury by inhibiting TLR4 signaling pathway.

Shikonin, a naphthoquinone isolated from the root of medical herb Lithospermum erythrorhizon, has been reported to have anti-inflammatory effect. However, there is no related research for the treatment of shikonin on hepaic injury. The purpose of this study was to investigate the effects of shikonin on D-Galactosamine and Lipopolysaccharide-induced hepatic injury in mice. Male BALB/c mice were pretreated with shikonin 1 h before LPS/D-GalN treatment. The pathological changes of hepatic injury were detected by H&E staining. The levels of TNF-α and IL-1ß in hepatic tissues were detected by ELISA. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also measured in this study. In addition, the expression of TLR4 and NF-κB were determined by western blot analysis. These results suggest that shikonin effectively prevents LPS/D-GalN-induced liver injury by inhibiting AST and ALT levels, as well as inflammatory cytokines TNF-α and IL-1ß production. The expression of TLR4 and NF-κB activation induced by LPS/D-GalN were also inhibited by treatment of shikonin. In vitro, shikonin significantly inhibited LPS-induced TNF-α and IL-1ß production, as well as TLR4 expression and NF-κB activation. In conclusion, the results of the present study suggest that shikonin attenuates LPS/D-GalN-induced hepatic injury by inhibiting TLR4 signaling pathway.

The protective effect of juglanin on fructose-induced hepatitis by inhibiting inflammation and apoptosis through TLR4 and JAK2/STAT3 signaling pathways in fructose-fed rats.

High fructose-feeding is an essential causative factor leading to the development and progression of hepatitis associated with high levels of endotoxin (LPS). Juglanin, as a natural compound extracted from the crude Polygonum aviculare, displayed inhibitory activity against inflammation response and cancer growth. However, researches about its role on anti-inflammation and apoptosis are far from available. Here, it is the first time that juglanin was administrated to investigate whether it inhibits fructose-feeding-induced hepatitis in rats and to elucidate the possible mechanism by which juglanin might recover it. Fructose-feeding rats were orally administrated with juglanin of 5, 10 and 20mg/kg for 6 weeks, respectively. Juglanin exerted prevention of fructose-feeding-stimulated increased LPS levels, accelerated alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) and up-regulated inflammatory cytokines expression in serum, mainly including tumor necrosis factor-alpha (TNF-a), Interleukin 1beta (IL-1ß), Interleukin 6 (IL-6) and Interleukin 18 (IL-18). Meanwhile, toll-like receptor 4 (TLR4)-modulated mitogen-activated protein kinase (MAPK)/nuclear factor kappa B (NF-κB) and apoptosis-related Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway are involved in the progression of hepatic injury and inflammation. And juglanin was found to suppress fructose-feeding-induced activation of these signaling pathways compared with the model group administrated only with fructose. These results indicate that juglanin represses inflammatory response and apoptosis via TLR4-regulated MAPK/NF-κB and JAK2/STAT3 signaling pathway respectively in rats with hepatitis induced by LPS for fructose-feeding. Treatment of juglanin might be an effective therapeutic strategy for preventing hepatitis.

[Mechanism of liver injury in severe acute pancreatitis rats and role of melatonin].

OBJECTIVE: To investigate the activation level of nuclear factor-kappaB (NF-kappaB) in liver injury caused by severe acute pancreatitis (SAP) and the protective role of melatonin against liver injury. METHODS: Ninety-six Sprague-Dawley (SD) rats were randomly divided into 3 equal groups: SAP group undergoing injection of sodium taurocholate to establish SAP models, melatonin (Mel) treatment group undergoing intraperitoneal injection 50 mg/kg 30 minutes before the establishment of SAP models, and sham operation group (Sham group). 4, 12, 24, and 48 hours after the onset of operation, blood samples were collected from the inferior vena casa of 8 rats from each group to measure the serum level of amylase (AMY) and alanine transaminase (ALT) by iodine colorimetry, and to detect the serum level of tumor necrosis factor-alpha (TNF-alpha) by ELISA. The livers were taken out to undergo pathological examination. Immunohistochemistry was used to examine the percentage of nuclear factor (NF)-kappaB in the hepatocytes. Terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) was used to determine the extent of hepatic apoptosis. RESULTS: The AMY and ALT levels at different time points of the SAP and Mel subgroups were all significantly higher than those of the sham operation subgroups (all P<0.05), and the AMY and ALT levels at different time points of the Mel subgroup were all significantly lower than those of the SAP subgroups (all P<0.05). The liver NF-kappaB activation level and hepatocellular apoptosis index of the SAP group increased since the fourth hour after the operation, and peaked at the time point of 24 hour, all significantly higher than those of the sham operation group (all P<0.05), and then declined. The TNF-alpha level at the time points of 12, 24, and 48 h in the SAP group were all significantly higher than those of the other 2 groups (all P<0.05). The levels of TNF-alpha, AMY, and ALT, the activity of NF-kappaB, and the extent of hepatocellular apoptosis at any time points of the Mel group were all significantly lower than those of the SAP group, but significantly higher than those of the sham operation group. Microscopy showed that the liver pathological damages of the Mel group were milder than those of the SAP group. CONCLUSION: SAP with liver injury is associated with the hepatic NF-kappaB activation leading to the production of NF-kappaB dependent cytokines and chemokines such as TNF-alpha. Melatonin reduces the apoptosis and necrosis in liver by inhibiting the activity of NF-kappaB and decreasing the expression of TNF-alpha.