Project description:The robust transcriptional plasticity of liver mediated through xenobiotic receptors underlies its ability to respond rapidly and effectively to diverse chemical stressors. Thus, drug-induced gene expression changes in liver serve not only as biomarkers of liver injury, but also as mechanistic sentinels of adaptation in metabolism, detoxification and tissue protection from chemicals. Modern RNA sequencing methods offer an unmatched opportunity to quantitatively monitor these processes in parallel and to contextualize the spectrum of dose-dependent stress, adaptation, protection and injury responses induced in liver by drug treatments. Using this approach, we profiled the transcriptional changes in rat liver following daily oral administration of 95 different compounds, many of which are known to be associated with clinical risk for drug induced liver injury (DILI) by diverse mechanisms.
Project description:<p>The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) has established the Drug-Induced Liver Injury Network (DILIN) to collect and analyze cases of severe liver injury caused by prescription drugs, over-the-counter drugs, and alternative medicines, such as herbal products and supplements.</p>
Project description:Liver injury is a core pathological process in the majority of liver diseases, yet the genetic factors predisposing individuals to its initiation and progression remain poorly understood. Here we show that asialoglycoprotein receptor 1 (ASGR1), a lectin specifically expressed in the liver, is downregulated in patients with liver fibrosis or cirrhosis and male mice with liver injury. ASGR1 deficiency exacerbates while its overexpression mitigates acetaminophen-induced acute and CCl4-induced chronic liver injuries in male mice. Mechanistically, ASGR1 binds to an endoplasmic reticulum stress mediator GP73 and facilitates its lysosomal degradation. ASGR1 depletion increases circulating GP73 levels and promotes the interaction between GP73 and BIP to activate endoplasmic reticulum stress, leading to liver injury. Neutralization of GP73 not only attenuates ASGR1 deficiency-induced liver injuries but also improves survival in mice received a lethal dose of acetaminophen. Collectively, these findings identify ASGR1 as a potential genetic determinant of susceptibility to liver injury and propose it as a therapeutic target for the treatment of liver injury.
Project description:In the present study, the proteomics approach identified potential protein signatures with high discriminative ability in TB patients with and without drug-induced liver injury which might play a crucial role in developing Anti-tubercular drug-induced liver injury.
Project description:Hepatic injury provoked by cold storage is a major problem affecting liver transplantation, as exposure to cold induces apoptosis in hepatic tissues. Long noncoding RNAs (lncRNAs) are increasingly understood to regulate apoptosis, but the contribution of lncRNAs to cold-induced liver injury remains unknown. Using RNA-seq, we determined the differential lncRNA expression profile in mouse livers after cold storage and found that expression of the lncRNA TUG1 was significantly down-regulated. Over-expression of TUG1 attenuated cold-induced apoptosis in mouse hepatocytes and liver sinusoidal endothelial cells LSECs, in part by blocking mitochondrial apoptosis and ER stress pathways. Moreover, TUG1 attenuated apoptosis, inflammation and oxidative stress in vivo in livers subjected to cold storage. Over-expression of TUG1 also improved hepatocyte function and prolonged hepatic graft survival rates in mice. These results suggest that the lncRNA TUG1 exerts a protective effect against cold-induced liver damage by inhibiting apoptosis in mice, and suggests a potential role for TUG1 as a target for the prevention of cold-induced liver damage in liver transplantation.
Project description:Fasiglifam (TAK-875), a G protein-coupled receptor 40 (GPR40) agonist, was a drug candidate for type 2 diabetes. However, its development was terminated in phase 3 trials due to liver safety concerns. Although TAK-875 was reported to inhibit hepatobiliary transporters and disturb bile acid disposition, pathogenic mechanisms of TAK-875-induced liver injury are not fully understood. In this study, we sought to identify the mechanisms with a hepatic genome-wide transcriptomic analysis in a murine model. We demonstrated that, among the three GPR40 agonists, TAK-875, AMG-837 and TUG-770, only TAK-875 induced acute liver injury in mice. Transcriptome profiles of TAK-875-exposed liver was compared with those of non-hepatotoxic analogues AMG-837 and TUG-770 as negative controls and those of classical hepatotoxicants concanavalin A and carbon tetrachloride as positive controls. The comparative hepatic transcriptome analyses revealed the enrichment of genes involved in inflammation, endoplasmic reticulum (ER) stress, apoptosis, and hepatic lipid accumulation, suggesting that these events play pathophysiologic roles in the development of TAK-875-induced liver injury. These results were validated by quantitative PCR with significant changes in chemokines, danger signals, ER stress mediators, proapoptotic factors, and hepatic steatosis markers only in TAK-875-exposed liver. Pretreatment of TAK-875-administered mice with an ER stress inhibitor 4-phenylbutyric acid (4-PBA) alleviated the liver injury. Consistent with the in vivo study, pretreatment of HepG2 cells with 4-PBA significantly improved the decrease of cell viability induced by TAK-875. In conclusion, by a comprehensive transcriptomic analysis of GPR40 agonists, we found multiple possible processes that contribute to TAK-875-induced acute liver injury in mice.
Project description:BACKGROUND & AIMS: c-Jun N-terminal kinase (JNK)1 and JNK2 are expressed in hepatocytes and have overlapping and distinct functions. JNK proteins are activated, via phosphorylation, in response to acetaminophen- or CCl4-induced liver damage; the level of activation correlates with the degree of injury. SP600125, a JNK inhibitor, has been reported to block acetaminophen-induced liver injury. We investigated the role of JNK in drug-induced liver injury (DILI) in liver tissues from patients and in mice with genetic deletion of JNK in hepatocytes. METHODS: We studied liver sections from patients with DILI (due to acetaminophen, phenprocoumon, non-steroidal anti-inflammatory drugs or autoimmune hepatitis), or patients without acute liver failure (controls), collected from a DILI Biobank in Germany. Levels of total and activated (phosphorylated) JNK were measured by immunohistochemistry and western blotting. Mice with hepatocyte-specific deletion of Jnk1 (Jnk1Îhepa) or combination of Jnk1 and Jnk2 (JnkÎhepa), as well as Jnk1-floxed C57BL/6 (control) mice, were given injections of CCl4 (to induce fibrosis) or acetaminophen (to induce toxic liver injury). We performed gene expression microarray, and phosphoproteomic analyses to determine mechanisms of JNK activity in hepatocytes. RESULTS: Liver samples from DILI patients contained more activated JNK, predominantly in nuclei of hepatocytes and in immune cells, than healthy tissue. Administration of acetaminophen to JnkÎhepa mice produced a greater level of liver injury than that observed in Jnk1Îhepa or control mice, based on levels of serum markers and microscopic and histologic analysis of liver tissues. Administration of CCl4 also induced stronger hepatic injury in JnkÎhepa mice, based on increased inflammation, cell proliferation, and fibrosis progression, compared to Jnk1Îhepa or control mice. Hepatocytes from JnkÎhepa mice given acetaminophen had an increased oxidative stress response, leading to decreased activation of AMPK, total protein AMPK levels, and pJunD and subsequent necrosis. Administration of SP600125 before or with acetaminophen protected JnkÎhepa and control mice from liver injury. CONCLUSIONS: In hepatocytes, JNK1 and JNK2 appear to have combined effects in protecting mice from CCl4- and acetaminophen-induced liver injury. It is important to study the tissue-specific functions of both proteins, rather than just JNK1, in the onset of toxic liver injury. JNK inhibition with SP600125 shows off-target effects. Livers and primary hepatocytes were isolated from wild type and JNKÎhepa (Jnk1Îhepa/global Jnk2-/-) double-knockout mice and subjected to gene expression profiling.
Project description:Liver zonation remains a critical aspect of understanding its response to acute injury. This study investigates the impact of acetaminophen-induced acute liver injury on zonal heterogeneity during early phases of injury. Through Ki67 staining, we observed a transient pause in proliferation specifically among mid-lobular hepatocytes during the initiation phase. Using spatial transcriptomics, immunostaining, and in vivo assays, we elucidated that mid-lobular hepatocytes upregulate the Atf4-Ddit3 axis, offering temporary protection at the cost of reduced proliferation mediated by Btg2. Our findings underscore the unique zonal metabolism of acetaminophen as a determinant of differential tissue responses across lobular regions. This study highlights how distinct liver zones exhibit varied responses during the early stages of acute injury, with mid-lobular hepatocytes showing an integrated stress response characterized by protective mechanisms that temporarily suppress proliferation.
Project description:The mechanism underlying the loss of normal liver tissues in liver cirrhosis, mainly hepatocytes, is not well-characterized. Endoplasmic reticulum (ER) stress-induced cell death has emerged as a potential mechanism for chronic liver diseases. We have previously demonstrated that cyclooxygenase-2 (COX-2) is closely related to the progress of liver cirrhosis. In this study, we aimed to verify whether hepatocytes COX-2 deficiency could protect liver injury via inducing ER stress in liver cirrhosis.