ObjectiveHepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) pathophysiology remains unclear. This study aims to characterise the molecular basis of HBV-ACLF using transcriptomics.MethodsFour hundred subjects with HBV-ACLF, acute-on-chronic hepatic dysfunction (ACHD), liver cirrhosis (LC) or chronic hepatitis B (CHB) and normal controls (NC) from a prospective multicentre cohort were studied, and 65 subjects (ACLF, 20; ACHD, 10; LC, 10; CHB, 10; NC, 15) among them underwent mRNA sequencing using peripheral blood mononuclear cells (PBMCs).ResultsThe functional synergy analysis focusing on seven bioprocesses related to the PBMC response and the top 500 differentially expressed genes (DEGs) showed that viral processes were associated with all disease stages. Immune dysregulation, as the most prominent change and disorder triggered by HBV exacerbation, drove CHB or LC to ACHD and ACLF. Metabolic disruption was significant in ACHD and severe in ACLF. The analysis of 62 overlapping DEGs further linked the HBV-based immune-metabolism disorder to ACLF progression. The signatures of interferon-related, neutrophil-related and monocyte-related pathways related to the innate immune response were significantly upregulated. Signatures linked to the adaptive immune response were downregulated. Disruptions of lipid and fatty acid metabolism were observed during ACLF development. External validation of four DEGs underlying the aforementioned molecular mechanism in patients and experimental rats confirmed their specificity and potential as biomarkers for HBV-ACLF pathogenesis.ConclusionsThis study highlights immune-metabolism disorder triggered by HBV exacerbation as a potential mechanism of HBV-ACLF and may indicate a novel diagnostic and treatment target to reduce HBV-ACLF-related mortality.

Isoniazid (INH), since its introduction in the year 1952, still serves as a frontline drug in tuberculosis treatment (1). Despite the fact that INH has been widely used as a first-line antitubercular agent (2, 3), its therapeutic value is usually accompanied by severe hepatotoxicity and lethal hepatic injury (4, 5). Although the pathophysiology of INH-induced liver injury might vary, the toxicity features of the drug, including hepatocellular steatosis, necrosis, and inflammatory infiltration, are nearly consistent (6, 7).Even though extensive studies expounding INH toxicity have been carried out, the exact mechanism of INH hepatotoxicity remains controversial. Among numerous established theories, an inflammatory stress theory has recently been widely used to explain the idiosyncrasy. One hypothesis is that inflammatory stress increases sensitivity to drug-induced liver injury (DILI) (8, 9). In this theory, an incidence of systemic inflammation might reduce the xenobiotic toxicity threshold, which could be easily accomplished by coadministration with an inflammatory agent (10), thus promoting drug toxicity. Lipopolysaccharide (LPS) is an outer cell wall membrane constituent of Gram-negative bacteria that has been comprehensively studied as an inflammatory agent with a major role in bacterial infections (11,12). Previous studies have suggested that LPS might intensify DILI (13-15), and, hence, a possible cornerstone role for LPS in INH-induced hepatotoxicity might be assumed.Oxidative stress, generated from the accumulation of reactive oxygen species (ROS), may be potentiated by different factors, including drugs and inflammation (16,17). In addition, oxidative stress plays a major role in several types of hepatic injury (18). Furthermore, with cytochrome P450 2E1 (CYP2E1) playing a major role in drug metabolism and the pathophysiology of DILI (19) and being considered a principal element in human susceptibility to chemical toxins (20), it plays a central part in oxidative stress, production of ROS, and hepatotoxic injury. Moreover, a previous report proposed that hepatic CYP2E1 plays a fundamental role in the propagation of INH-induced hepatotoxicity, mainly throughout ROS generation (21). Nevertheless, a full understanding of CYP2E1 as a major hepatotoxin-forming, catalyzing enzyme and its influence on INH-induced liver damage has not been completely achieved.Studies of the hepatotoxic mechanisms of INH were previously conducted using different animal models; however, results were accompanied by the absence of certain features of INH toxicity, i.e., delayed onset or inconsistency in severity compared to that in hu-

Isoniazid (INH) is an antituberculosis drug associated with idiosyncratic liver injury in susceptible patients. INH-induced hepatotoxicity remains a significant clinical problem, but the underlying mechanisms are still unclear, despite the growing evidence that INH and/or its major metabolite, hydrazine, play an important role in hepatotoxicity.

No abstract

No abstract

Pristimerin, a natural triterpenoid isolated form Celastrus and Maytenus spp, has been shown to possess a variety of biological and pharmacological effects. Recently, pristimerin has attracted more attention, especially for its potential anticancer activities. The anticancer activities of pristimerin have been illustrated in various cancer cell lines and animal models. It has been found to inhibit in vitro and in vivo proliferation, survival, angiogenesis and metastasis of tumor cells. These activities have been attributed to its modulation of various molecular targets such as cyclins, apoptosis- related proteins, proteasome activity, reactive oxygen species, as well as NF-kB, AKT/mTOR and MAPK/ERK pathways. This mini-review discussed the cellular impact and animal studies of pristimerin treatment, with more attention on the various molecular targets of pristimerin.

Triptolide (TP), a diterpenoid isolated from Tripterygium wilfordii Hook F, has an excellent pharmacological profile of immunosuppression and anti-tumor activities, but its clinical applications are severely restricted due to its severe and cumulative toxicities. The farnesoid X receptor (FXR) is the master bile acid nuclear receptor and plays an important role in maintaining hepatic metabolism homeostasis. Hepatic Sirtuin (Sirt1) is a key regulator of the FXR signaling pathway and hepatic metabolism homeostasis. The aims of this study were to determine whether Sirt1/FXR signaling pathway plays a critical role in TP-induced hepatotoxicity. Our study revealed that the intragastric administration of TP (400 μg/kg body weight) for 28 consecutive days increased bile acid accumulation, suppressed hepatic gluconeogenesis in rats. The expression of bile acid transporter BSEP was significantly reduced and cholesterol 7α-hydroxylase (CYP7A1) was markedly increased in the TP-treated group, whereas the genes responsible for hepatic gluconeogenesis were suppressed in the TP-treated group. TP also modulated the FXR and Sirt1 by decreasing its expression both in vitro and in vivo. The Sirt1 agonist SRT1720 and the FXR agonist obeticholic acid (OCA) were used both in vivo and in vitro. The remarkable liver damage induced by TP was attenuated by treatment with either SRT1720 or OCA, as reflected by decreased levels of serum total bile acids and alkaline phosphatase and increased glucose levels. Meanwhile, SRT1720 significantly alleviated TP-induced FXR suppression and FXR-targets involved in hepatic lipid and glucose metabolism. Based on these results, we conclude that Sirt1/FXR inactivation plays a critical role in TP-induced hepatotoxicity. Moreover, Sirt1/FXR axis represents a novel therapeutic target that could potentially ameliorate TP-induced hepatotoxicity.

g Pyrazinamide (PZA) is an essential antitubercular drug, but little is still known about its hepatotoxicity potential. This study examined the effects of PZA exposure on zebrafish (Danio rerio) larvae and the mechanisms underlying its hepatotoxicity. A transgenic line of zebrafish larvae that expressed enhanced green fluorescent protein (EGFP) in the liver was incubated with 1, 2.5, and 5 mM PZA from 72 h postfertilization (hpf). Different endpoints such as mortality, morphology changes in the size and shape of the liver, histological changes, transaminase analysis and apoptosis, markers of oxidative and genetic damage, as well as the expression of certain genes were selected to evaluate PZA-induced hepatotoxicity. Our results confirm the manner of PZA dose-dependent hepatotoxicity. PZA was found to induce marked injury in zebrafish larvae, such as liver atrophy, elevations of transaminase levels, oxidative stress, and hepatocyte apoptosis. To further understand the mechanism behind PZA-induced hepatotoxicity, changes in gene expression levels in zebrafish larvae exposed to PZA for 72 h postexposure (hpe) were determined. The results of this study demonstrated that PZA decreased the expression levels of liver fatty acid binding protein (L-FABP) and its target gene, peroxisome proliferator-activated receptor ␣ (PPAR-␣), and provoked more severe oxidative stress and hepatitis via the upregulation of inflammatory cytokines such as tumor necrosis factor alpha (TNF-␣) and transforming growth factor ␤ (TGF-␤). These findings suggest that L-FABP-mediated PPAR-␣ downregulation appears to be a hepatotoxic response resulting from zebrafish larva liver cell apoptosis, and L-FABP can be used as a biomarker for the early detection of PZA-induced liver damage in zebrafish larvae. P yrazinamide (PZA) is an important first-line drug in tuberculosis (TB) combination chemotherapy and is used during the initial 2 months of treatment for its remarkable sterilizing activity (1). Hepatotoxicity is the major adverse effect of PZA and usually occurs in the first 2 months of treatment (2). Previously reported studies showed a high incidence of hepatotoxicity with a high dosage of 40 to 70 mg/kg of body weight and a low rate of liver injury with a daily dose of Ͻ35 mg/kg (3). Although a reduction of the clinical dose considerably decreased the rate of PZA-induced hepatotoxic side effects, PZA is still considered to induce higher hepatotoxicity than other first-line antituberculosis drugs (4, 5). PZA hepatotoxicity cannot be ignored; however, little is known about the exact mechanism of PZA-induced hepatotoxicity.Previous research, by using microarray analyses and proteomics studies, found that metabolism, inflammation, and oxidative stress pathways were probably involved in PZA-induced hepatotoxicity (6, 7). A recent investigation showed that the metabolite 5-hydroxypyrazinoic acid (5-OH-PA) is responsible for PZAinduced hepatotoxicity (8). Despite an increasing number of researchers who are trying to reevaluate the hepatotoxic potentia...