Pathogenesis Of Drug-induced Liver Injury Research Articles

Endoplasmic reticulum-targeted fluorescent probe with aggregation-induced emission features for imaging peroxynitrite in drug-induced liver injury model

Drug-induced liver injury (DILI) poses a severe threat to public health. Endoplasmic reticulum (ER) stress contributes significantly to DILI pathogenesis, with peroxynitrite (ONOO−) identified as a pivotal indicator. However, the temporal and spatial fluctuations of ONOO− associated with ER stress in the pathogenesis of DILI remain unclear. Herein, a novel ER-specific near-infrared (NIR) probe (QM-ONOO) with aggregation-induced emission (AIE) features for monitoring ONOO− fluctuations in DILI was elaborately constructed. QM-ONOO exhibited excellent ER-targeting specificity, a large Stoke’s shift, and a low detection limit (26.9 nM) toward ONOO−. QM-ONOO performed well in imaging both exogenous and endogenous ONOO− in HepG2 cells. Furthermore, molecular docking calculations validated the ER-targeting mechanism of QM-ONOO. Most importantly, using this probe allowed us to intuitively observe the dynamic fluctuations of ONOO− during the formation and remediation processes of DILI in the acetaminophen (APAP)-induced mouse model. Consequently, this work provides a promising tool for in-depth research of ONOO− associated pathological processes in DILI.

Gut-Liver Axis as a Therapeutic Target for Drug-Induced Liver Injury.

Drug-induced liver injury (DILI) is a liver disease that remains difficult to predict and diagnose, and the underlying mechanisms are yet to be fully clarified. The gut-liver axis refers to the reciprocal interactions between the gut and the liver, and its homeostasis plays a prominent role in maintaining liver health. It has been recently reported that patients and animals with DILI have a disrupted gut-liver axis, involving altered gut microbiota composition, increased intestinal permeability and lipopolysaccharide translocation, decreased short-chain fatty acids production, and impaired bile acid metabolism homeostasis. The present review will summarize the evidence from both clinical and preclinical studies about the role of the gut-liver axis in the pathogenesis of DILI. Moreover, we will focus attention on the potential therapeutic strategies for DILI based on improving gut-liver axis function, including herbs and phytochemicals, probiotics, fecal microbial transplantation, postbiotics, bile acids, and Farnesoid X receptor agonists.

Hepatocyte DDX3X protects against drug-induced acute liver injury via controlling stress granule formation and oxidative stress

Drug-induced liver injury (DILI) is the leading cause of acute liver failure (ALF). Continuous and prolonged hepatic cellular oxidative stress and liver inflammatory stimuli are key signatures of DILI. DEAD-box helicase 3, X-linked (DDX3X) is a central regulator in pro-survival stress granule (SG) assembly in response to stress signals. However, the role of DDX3X in DILI remains unknown. Herein, we characterized the hepatocyte-specific role of DDX3X in DILI. Human liver tissues of DILI patients and control subjects were used to evaluate DDX3X expression. APAP, CCl4 and TAA models of DILI were established and compared between hepatocyte-specific DDX3X knockout (DDX3XΔhep) and wild-type control (DDX3Xfl/fl) mice. Hepatic expression of DDX3X was significantly decreased in the pathogenesis of DILI compared with controls in human and mice. Compared to DDX3Xfl/fl mice, DDX3XΔhep mice developed significant liver injury in multiple DILI models. DDX3X deficiency aggravates APAP induced oxidative stress and hepatocyte death by affecting the pro-survival stress granule (SG) assembly. Moreover, DDX3X deficiency induces inflammatory responses and causes pronounced macrophage infiltration. The use of targeted DDX3X drug maybe promising for the treatment of DILI in human.

Exploring the Hepatotoxicity of Drugs through Machine Learning and Network Toxicological Methods

Background: The prediction of the drug-induced liver injury (DILI) of chemicals is still a key issue of the adverse drug reactions (ADRs) that needs to be solved urgently in drug development. The development of a novel method with good predictive capability and strong mechanism interpretation is still a focus topic in exploring the DILI. Objective: With the help of systems biology and network analysis techniques, a class of descriptors that can reflect the influence of drug targets in the pathogenesis of DILI is established. Then a machine learning model with good predictive capability and strong mechanism interpretation is developed between these descriptors and the toxicity of DILI. Methods: After overlapping the DILI disease module and the drug-target network, we developed novel descriptors according to the number of drug genes with different network overlapped distance parameters. The hepatotoxicity of drugs is predicted based on these novel descriptors and the classical molecular descriptors. Then the DILI mechanism interpretations of drugs are carried out with important network topological descriptors in the prediction model. Results: First, we collected targets of drugs and DILI-related genes and developed 5 NT parameters (S, Nds=0, Nds=1, Nds=2, and Nds>2) based on their relationship with a DILI disease module. Then hepatotoxicity predicting models were established between the above NT parameters combined with molecular descriptors and drugs through the machine learning algorithms. We found that the NT parameters had a significant contribution in the model (ACCtraining set=0.71, AUCtraining set=0.76; ACCexternal set=0.79, AUCexternal set=0.83) developed by these descriptors within the applicability domain, especially for Nds=2, and Nds>2. Then, the DILI mechanism of acetaminophen (APAP) and gefitinib are explored based on their risk genes related to ds=2. There are 26 DILI risk genes in the regulation of cell death regulated with two steps by 5 APAP targets, and gefitinib regulated risk gene of CLDN1, EIF2B4, and AMIGO1 with two steps led to DILI which fell in the biological process of response to oxygen-containing compound, indicating that different drugs possibly induced liver injury through regulating different biological functions. Conclusion: A novel method based on network strategies and machine learning algorithms successfully explored the DILI of drugs. The NT parameters had shown advantages in illustrating the DILI mechanism of chemicals according to the relationships between the drug targets and the DILI risk genes in the human interactome. It can provide a novel candidate of molecular descriptors for the predictions of other ADRs or even of the predictions of ADME/T activity.

Role of oxidative stress and endoplasmic reticulum stress in drug-induced liver injury

The pathogenesis of drug-induced liver injury (DILI) is still in an early stage of research. However, investigators have shown that both oxidative stress and endoplasmic reticulum (ER) stress play a significant role in the pathological mechanism. However, there is little in-depth literature about these two mechanisms. In order to prevent and improve the clinical symptoms of DILI, it is particularly important to study its pathogenesis. In this review article, the role of ER and oxidative stress in DILI is thoroughly discussed.

Immunophenotyping to improve the mechanistic understanding of idiosyncratic drug-induced liver injury: clinical implications and future directions

The late event onset of a fraction of idiosyncratic drug-induced liver injury (DILI) cases and the link observed by genome-wide association studies (GWASs) of certain human leucocyte antigen (HLA) alleles with DILI due to specific drugs support the crucial role of the immune system (both innate and adaptive) in the pathogenesis of DILI. Recent advances in both flow and mass cytometry have allowed the profiling of all major immune cell types in a given sample. Therefore, determining the lymphocyte populations in samples from patients with DILI would facilitate the development of specific biomarkers for DILI diagnosis and prognosis. To date, a few studies have explored the immune landscape in DILI. In a recent study of leukocyte immunophenotyping using flow cytometry from the Spanish DILI Registry, an important role of adaptive immune response in DILI is suggested. DILI patients had significantly higher levels of T helper 1 (Th1) cells and activated helper and cytotoxic T cells than healthy controls. Furthermore, the increased expression of negative immune checkpoints and ligands in DILI patients could reflect a restoration of the immune homeostasis. Differences in the profile of cytokines in DILI patients from the Drug-Induced Liver Injury Network (DILIN) also suggest an involvement of both innate and adaptive immune systems in DILI development and prognosis. Moreover, several studies based on immunophenotyping of liver infiltrates showed a distinctive pattern of cellular infiltrates in patients with immune checkpoint inhibitors (ICIs)-DILI, with lower levels of plasma cells, CD20+ B cells and CD4+ T cells than in autoimmune hepatitis (AIH) patients. These pioneering studies highlight the importance of immunophenotyping for the mechanistic understanding of DILI. In this review, available data on immunophenotyping in DILI are gathered, and the potential clinical applications of cutting-edge, novel immunophenotyping techniques are discussed.

A Circular Dichroism and Photoacoustic Dual-Mode Probe for Detection In Vitro and Imaging In Vivo of Hydroxyl Radicals.

The drug toxicity is a long-term concern in contemporary medical research. Serious drug toxicity may cause acute liver failure or even patient death. Currently, the pathogenesis of drug-induced liver injury (DILI) is not entirely clear, and there is still no specific treatment for patients with DILI. Accordingly, improving the diagnosis and treatment level of DILI is a major challenge facing the basic and clinical research in relevant fields. To address these, an ·OH-activated circular dichroism (CD) and photoacoustic (PA) dual-mode nanoprobe was here designed and synthesized. The probe was prepared using chiral d/l-cysteine and polymolybdate as raw materials to form a nanocomplex with chiral properties (Ox-POM@d/l-Cys) based on the interaction between metal ions and sulfhydryl groups in Ox-POM@d/l-Cys. In vitro and in vivo experimental results have shown that the as-proposed dual-mode nanoprobe can be used not only for CD spectral detection of Fenton's reagent but also for PA imaging monitoring of ·OH. More importantly, inspired by the NIR PA properties, the Ox-POM@d/l-Cys probe was used for the first time to detect ·OH in DILI mice. This will provide very useful information for the diagnosis and treatment of DILI disease.

Diketopyrrolopyrrole-based sensor for over-expressed peroxynitrite in drug-induced hepatotoxicity via ratiometric fluorescence imaging

Early diagnosis and detection of drug-induced liver injury (DILI) is great significance for the effective prevention and treatment of patients with liver injury. Studies indicate that the up-regulation of peroxynitrite (ONOO−) levels in liver is profoundly involved in acetaminophen (APAP)-induced liver injury. Herein, we constructed diketopyrrolopyrrole (DPP)-based ratiometric fluorescent probes (DPP-DH-P and DPP-DEG-P) for detecting and imaging ONOO−. Comparing two probes, DPP-DEG-P exhibited higher signal-to-noise ratio (2750-fold) and lower detection limit (3.5 nM) for tracking ONOO− in solution. DPP-DH-P possessing better biocompatibility had been successfully applied to monitor the fluctuation of ONOO− in LPS/IFN-γ or APAP-treated hepatocytes with a high signal-to-noise ratio (20-fold) by ratiometric imaging. Moreover, the probe was used to evaluate the repair effect of glutathione on DILI. We unexpectedly discovered that DPP-DH-P and DPP-DH targeted lysosomes and mitochondria, respectively. Based on the change of ONOO− induced by APAP, we observed that DPP-DH-P and the generated DPP-DH diffused from lysosome into cytoplasm, and DPP-DH did not target mitochondria due to the effect of endogenous ONOO−, these indirectly reflected the dysfunction of organelles. Observably, this work will accelerate a deeper comprehending for the pathogenesis of DILI, and furnish an effective tool for the diagnosis and treatment of DILI.

A novel near-infrared viscosity probe based on synergistic effect of AIE property and molecular rotors for mitophagy imaging during liver injury

Mitophagy, a specialized form of autophagy, holds the key to cellular metabolism and physiology. Viscosity is a significant marker for visualization of the mitophagy process in real-time. Hence, development of well-performing viscosity probe is beneficial to study mitophagy-related dynamic physiological and pathological processes. Here, a new strategy was proposed by combination of AIE property and molecular rotors to design novel viscosity probe. The probe named TPA-Py was obtained by Knoevenagel condensation reaction of AIE unit and pyridine salt, which giving the probe excellent near-infrared emission, good water-solubility and mitochondrial targeting ability. Most importantly, TPA-Py owns two rotatable parts of triphenylamine and double bond, enabling the probe to equip with AIE property and sensitive recognition units for viscosity. With the environmental viscosity increasing, the rotation of the molecular rotor and the AIE unit is restricted effectively, the probe displayed strong fluorescence. Then, TPA-Py was successfully employed for monitoring the mitophagy process in A549 cells by imaging viscosity alterations. As mitophagy constitutes an important consideration in the pathogenesis of drug-induced liver injury, TPA-Py was also applied to explore the variation of viscosity in production and remediation pathways of APAP-induced liver injury. These results demonstrated that TPA-Py was a highly sensitive viscosity probe which holds great potential of biological applications.

Research Progress of Pharmacogenomics in Drug-Induced Liver Injury.

Background: Drug-induced liver injury (DILI) is a common and serious adverse drug reaction with insufficient clinical diagnostic strategies and treatment methods. The only clinically well-received method is the Roussel UCLAF Causality Assessment Method scale, which can be applied to both individuals and prospective or retrospective studies. However, in severe cases, patients with DILI still would develop acute liver failure or even death. Pharmacogenomics, a powerful tool to achieve precision medicine, has been used to study the polymorphism of DILI related genes.Summary: We summarized the pathogenesis of DILI and findings on associated genes and variations with DILI, including but not limited to HLA genes, drug metabolizing enzymes, and transporters genes, and pointed out further fields for DILI related pharmacogenomics study to provide references for DILI clinical diagnosis and treatment.Key Messages: At present, most of the studies are mainly limited to CGS and GWAS, and there is still a long way to achieve clinical transformation. DNA methylation could be a new consideration, and ethnic differences and special populations also deserve attention.

Immune-Mediated Drug-Induced Liver Injury: Immunogenetics and Experimental Models.

Drug-induced liver injury (DILI) is a challenging clinical event in medicine, particularly because of its ability to present with a variety of phenotypes including that of autoimmune hepatitis or other immune mediated liver injuries. Limited diagnostic and therapeutic tools are available, mostly because its pathogenesis has remained poorly understood for decades. The recent scientific and technological advancements in genomics and immunology are paving the way for a better understanding of the molecular aspects of DILI. This review provides an updated overview of the genetic predisposition and immunological mechanisms behind the pathogenesis of DILI and presents the state-of-the-art experimental models to study DILI at the pre-clinical level.

Association between human leukocyte antigen gene polymorphism and drug-induced liver injury

Drug-induced liver injury (DILI) is one of the common adverse drug reactions in clinical practice, and it is difficult to diagnose and treat and may easily develop into acute liver failure. Related pharmacogenomics studies have found a strong genetic correlation between human leukocyte antigen (HLA) genes and DILI. This article reviews the research advances in HLA gene polymorphism in DILI, in order to reveal the role of immune factors in the pathogenesis of DILI, identify related genetic biomarkers, and improve the safety of clinical medication.

Pathogenesis of drug-induced liver injury: Current understanding and future needs

The risk factors for drug-induced liver injury (DILI) involve host factors (including general non-genetic factors and idiosyncratic genetic and immune factors), drug-related factors, and environmental factors. The pathogenesis of DILI can be classified as intrinsic (or direct) hepatotoxicity, idiosyncratic hepatotoxicity, and indirect hepatotoxicity, as well as tumorigenicity and carcinogenicity of some drugs to the liver. The pathogenesis of different types of hepatotoxicity not only has significant differences, but also has internal correlation at multiple links. The three-step model centered on mitochondrial permeability transition (MPT) and a two-stage model with liver cell regeneration and liver tissue repair capacity as the determinants of different outcomes display the mechanism progress of DILI from different perspectives. Clarification of the complex pathogenesis of DILI needs long-term collection of clinical cases and systematic studies, which is of great significance for the scientific prevention, diagnosis, and treatment of DILI.

Drug-induced liver injury: Advances and confusions in treatment

Drug-induced liver injury (DILI) is one of the most common and serious adverse drug reactions and can lead to acute liver failure and even death in severe cases. The pathogenesis of DILI has not been fully clarified, and there is significant individual difference. There is no effective treatment for advanced DILI except liver transplantation, and therefore, early diagnosis and precise treatment are of particular importance. This article reviews the important research advances and difficult issues in the treatment of DILI in recent years.

Hepatic bile formation: bile acid transport and water flow into the canalicular conduit.

Advances in molecular biology identifying the many carrier-mediated organic anion transporters and advances in microscopy that have provided a more detailed anatomy of the canalicular conduit make updating the concept of osmotically determined canalicular flow possible. For the most part water flow is not transmembrane but via specific pore proteins in both the hepatocyte and the tight junction. These pores independently regulate the rate at which water flows in response to an osmotic gradient and therefore are determinants of canalicular bile acid concentration. Review of the literature indicates that the initial effect on hepatic bile flow of cholestatic agents such as Thorazine and estradiol 17β-glucuronide are on water flow and not bile salt export pump-mediated bile acid transport and thus provides new approaches to the pathogenesis of drug-induced liver injury. Attaining a micellar concentration of bile acids in the canaliculus is essential to the formation of cholesterol-lecithin vesicles, which mostly occur in the periportal region of the canalicular conduit. The other regions, midcentral and pericentral, may transport lesser amounts of bile acid but augment water flow. Broadening the concept of how hepatic bile flow is initiated, provides new insights into the pathogenesis of canalicular cholestasis.

Drug-induced liver injury: from pathogenesis to treatment

The article presents data on classification, pathogenesis, clinical picture, diagnosis and differentiated treatment tactics, as well as practical algorithm for recognizing and preventing the development of drug-induced liver injury. Pathogenesis of drug-induced liver injury is analyzed, mechanisms of drug metabolism are explained, metabolism phases are described. Four main mechanisms of the pathological effect of drugs on the liver are identified: direct toxic effect on hepatocytes; toxic effect of drug metabolites; immunoallergic liver injury; idiosyncrasy. Peculiar attention is paid to the pathogenesis of drug-induced cholestasis. Direct hepatotoxic reactions develop according to the cytolytic (hepatocellular, parenchymal), cholestatic or mixed option. The most commonly diagnosed clinical variant of drug-induced liver injury is drug-induced hepatitis. Five forms of hepatitis induced by the use of pharmacological agents are distinguished: drug-induced hepatitis with an isolated increase in transaminases (anti-TB drugs, methyldopa, amiodarone, statins); acute hepatitis with jaundice; pseudo-surgical form of acute hepatitis: abdominal pain, fever, jaundice, enlarged gall bladder (cytostatics, antidepressants, antiarrhythmic drugs); severe forms of acute hepatitis with liver failure; chronic drug hepatitis. International diagnostic criteria, basic data on morphological liver changes are presented. Action of ursodeoxycholic acid is explained. It has a litholytic, anticholestatic, cytoprotective, immunomodulating, anti-inflammatory, antitoxic, hypocholesterolemic effect, modulates apoptosis, has a differentiated effect on the regeneration of hepatocytes.

Visualization of Dynamic Changes in Labile Iron(II) Pools in Endoplasmic Reticulum Stress-Mediated Drug-Induced Liver Injury.

Drug-induced liver injury (DILI) can cause liver failure and even death in severe cases, gravely threatening human health. The treatment of DILI remains a clinical challenge, mainly due to the lack of efficient and accurate diagnosis. Therefore, developing an accurate diagnosis approach is imperative to boost the timely treatment for DILI. As the primary organ of iron storage, liver's functions are tightly linked to iron homeostasis. Thus, monitoring iron homeostasis is promising for the diagnosis and treatment of DILI. Hence, we reported a new near-infrared fluorescent probe (LCy7) that enables real-time and in vivo visualizing of Fe2+ in drug-induced liver injury. In this design, Fe2+ would bind to the N4O ligand in LCy7 and conduce to the C-O bond broken in the presence of O2, which restore the masked QCy7 emitting luminous near-infrared fluorescence. Utilizing LCy7, the increase in Fe2+ was distinctly witnessed in hepatocytes under endoplasmic reticulum stress by acetaminophen (APAP) stimulation. In vivo near-infrared fluorescence imaging revealed the conspicuous rise in Fe2+ in the liver of mice during APAP-induced liver injury. We further unprecedentedly disclosed that endoplasmic reticulum stress was accompanied by the overload of Fe2+ in injured liver of these mice. Collectively, this work will facilitate a greater understanding of the pathogenesis of DILI, and also provide a powerful new tool for DILI diagnosis and treatment.

CCL5 deficiency promotes liver repair by improving inflammation resolution and liver regeneration through M2 macrophage polarization.

Despite the diverse etiologies of drug-induced liver injury (DILI), innate immunity activation is a common feature involved in DILI progression. However, the involvement of innate immunity regulation in inflammation resolution and liver regeneration in DILI remains obscure. Herein, we identified the chemokine CCL5 as a central mediator of innate immunity regulation in the pathogenesis of DILI. First, we showed that serum and hepatic CCL5 levels are elevated in both DILI patients and an APAP-induced liver injury (AILI) mouse model. Interestingly, both nonparenchymal cells and stressed hepatocytes are cell sources of CCL5 induction in response to liver injury. Functional experiments showed that CCL5 deficiency has no effect on the early phase of AILI but promotes liver repair in the late phase mainly by promoting inflammation resolution and liver regeneration, which are associated with an increased number of hepatic M2 macrophages. Mechanistically, CCL5 can directly activate M1 polarization and impede M2 polarization through the CCR1- and CCR5-mediated activation of the MAPK and NF-κB pathways. We then showed that CCL5 inhibition mediated by either a CCL5-neutralizing antibody or the antagonist Met-CCL5 can greatly alleviate liver injury and improve survival in an AILI mouse model. Our data demonstrate CCL5 induction during DILI, identify CCL5 as a novel innate immunity regulator in macrophage polarization, and suggest that CCL5 blockage is a promising therapeutic strategy for the treatment of DILI.

Genetic Polymorphisms Implicated in Nonalcoholic Liver Disease or Selected Other Disorders Have No Influence on Drug-Induced Liver Injury.

With the application of genetic testing to contemporary medical diagnostics and practice, it has become apparent that the phenotypes of many disorders are modulated by host genetic factors. The aim of the current study was to determine whether selected single nucleotide polymorphisms (SNPs) unrelated to the human leukocyte antigen region or other immune pathways, including those associated with nonalcoholic fatty liver disease (NAFLD), may influence development, severity, or outcomes of drug‐induced liver injury (DILI). Thirteen variants previously associated with NAFLD and/or selected other liver diseases were tested in 832 Caucasian DILI cases and 10,397 Caucasian population controls. DILI cases were attributed to multiple agents (177 individual drugs), with 56 cases due to herbal/dietary supplement products. Allele frequencies were imputed from recent genome‐wide association studies and compared to those for European control samples from the Gnomad database. Significance was tested by linear regression or logistic regression, depending on the nature of the trait. Any variant that passed the Bonferroni threshold of P < 0.0004 (0.0513) was considered a significant association. None of the variants proved to be significantly associated with DILI as phenotype nor with any of the selected severity traits. Among the variants studied, rs1421085, found in the fat mass and obesity associated (FTO) gene, showed a marginal protective effect (odds ratio, 0.8; 95% confidence interval, 0.77‐0.95; P = 0.005). None of the genetic polymorphisms tested were significantly associated with the risk of development, severity, or outcome of DILI. Conclusion: SNPs implicated in common liver diseases, such as NAFLD, do not play a substantial role in DILI pathogenesis across agents. It remains possible that these variants could be involved with DILI due to single agents, but this will require the evaluation of larger numbers of bona fide cases.

Drug Hepatotoxicity

Idiosyncratic drug-induced liver injury (DILI) caused by xenobiotics (drugs, herbals, and dietary supplements) is an elusive liver disease presenting with a range of phenotypes and severity, including acute hepatitis that is indistinguishable from viral hepatitis, autoimmune hepatitis, steatosis, fibrosis or rare chronic vascular syndromes, asymptomatic liver test abnormalities,and acute liver failure. Case definition and characterization using liver biochemistry and histology are crucial for appropriate phenotyping. The incidence of DILI is probably higher than expected by the cases that are identified in clinical practice because of misdiagnosis and underreporting.The pathogenesis of DILI is complex, depending on the interaction of a drug’s physicochemical properties and host factors. Genome-wide association studies have identified several alleles from the major histocompatibility complex system, indicating a fundamental role of the adaptive immune system in DILI pathogenesis. As specific biomarkers for hepatotoxicity are still not available, the diagnosis of DILI remains one of exclusion of the alternative causes of liver damage. Structured causality assessment using the Roussel Uclaf Causality Assessment Method (RUCAM) or previously Council for International Organizations of Medical Sciences (CIOMS) instrument adds consistency to the diagnostic process, although there is room for improvement in the scale domains and score weighting. The therapy for idiosyncratic hepatotoxicity is supportive and relies on the prompt withdrawal of the offending agent. Corticosteroid therapy for hypersensitivity reactions or ursodeoxycholicacid for prolonged cholestasis is empirically used, although the degree of evidence is low. Existing databases have enabled a better prediction of immediate and long-term DILI prognosis. Multivariate models have identified clinical and analytical variables as predictive of acute liver failure and mortality as well as of chronic DILI. This review contains 2 figures, 5 tables and 55 references Key Words: adaptive immune system;causality assessment;drug-induced liver injury; epidemiology; HLA alleles; pharmacogenetics; registries; risk factors