Methodological considerations for measuring biofluid-based microRNA biomarkers.

MicroRNAs (miRNAs) are small non-coding RNA that regulate the expression of messenger RNA and are implicated in almost all cellular processes. Importantly, miRNAs can be released extracellularly and are stable in these matrices where they may serve as indicators of organ or cell-specific toxicity, disease, and biological status. There has thus been great enthusiasm for developing miRNAs as biomarkers of adverse outcomes for scientific, regulatory, and clinical purposes.

Glutamate dehydrogenase as a biomarker for mitotoxicity; insights from furosemide hepatotoxicity in the mouse.

Glutamate dehydrogenase (GLDH) is a liver-specific biomarker of hepatocellular damage currently undergoing qualification as a drug development tool. Since GLDH is located within the mitochondrial matrix, it has been hypothesized that it might also be useful in assessing mitotoxicity as an initiating event during drug-induced liver injury. According to this hypothesis, hepatocyte death that does not involve primary mitochondrial injury would result in release of intact mitochondria into circulation that could be removed by high speed centrifugation and result in lower GLDH activity measured in spun serum vs un-spun serum.

Cannabidiol and Abnormal Liver Chemistries in Healthy Adults: Results of a Phase I Clinical Trial.

Liver safety concerns were raised in randomized controlled trials of cannabidiol (CBD) in patients with Lennox-Gastaut and Dravet syndromes, but the relevance of these concerns to healthy adults consuming CBD is unclear. The objective of this manuscript is to report on liver safety findings from healthy adults who received therapeutic daily doses of CBD for ~ 3.5 weeks and to investigate any correlation between transaminase elevations and baseline characteristics, pharmacogenetic, and pharmacokinetic data.

HLA associations with infliximab-induced liver injury.

Biomarkers that are able to identify patients at risk of drug-induced liver injury (DILI) after treatment with infliximab could be important in increasing the safety of infliximab use. We performed a genetic analysis to identify possible human leukocyte antigen (HLA) associations with DILI in European Caucasian users of infliximab in a retrospective study of 16 infliximab-DILI patients and 60 matched controls. In infliximab-associated liver injury, multiple potentially causal individual HLA associations were observed, as well as possible haplotypes.

Hepatocyte-Derived Exosomes Promote Liver Immune Tolerance: Possible Implications for Idiosyncratic Drug-Induced Liver Injury.

Most idiosyncratic drug-induced liver injury appears to result from an adaptive immune attack on the liver. Recent evidence suggests that the T-cell response may be facilitated by the loss of immune tolerance. In this study, we explored the hypothesis that constitutively released hepatocyte-derived exosomes (HDE) are important for maintaining normal liver immune tolerance.

Serum biomarkers of drug-induced liver injury: Current status and future directions.

Drug-induced liver injury (DILI), which is caused by drugs and herbal or dietary supplements, remains a serious concern for drug developers, regulators, and clinicians; however, serum biomarkers utilized to detect and monitor DILI have not changed in decades and have limitations. Data-driven mathematical modeling that incorporates the release and clearance kinetics of traditional biomarkers has improved their use in the prediction of liver safety liabilities for new drug candidates. Several newer biomarkers have shown promise in terms of liver specificity, predicting the outcome of DILI events, and providing insight into its underlying mechanisms.

A Mutation in the Borcs7 Subunit of the Lysosome Regulatory BORC Complex Results in Motor Deficits and Dystrophic Axonopathy in Mice.

Lysosomes play a critical role in maintenance of the integrity of neuronal function, and mutations in genes that contribute to lysosome formation, transport, and activity are associated with neurodegenerative disorders. Recently, the multisubunit complex, BLOC-one-related complex (BORC), has been shown to be involved in positioning lysosomes within the cytoplasm, although the consequences of altered BORC function in adult animals have not been established. We show that a spontaneous truncation mutation in the mouse Borcs7 gene, identified through whole-genome sequencing followed by genetic complementation, results in progressive axonal dystrophy with dramatic impairment of motor function.

Candidate biomarkers for the diagnosis and prognosis of drug-induced liver injury: An international collaborative effort.

Current blood biomarkers are suboptimal in detecting drug-induced liver injury (DILI) and predicting its outcome. We sought to characterize the natural variabilty and performance characteristics of 14 promising DILI biomarker candidates. Serum or plasma from multiple cohorts of healthy volunteers (n = 192 and n = 81), subjects who safely took potentially hepatotoxic drugs without adverse effects (n = 55 and n = 92) and DILI patients (n = 98, n = 28, and n = 143) were assayed for microRNA-122 (miR-122), glutamate dehydrogenase (GLDH), total cytokeratin 18 (K18), caspase cleaved K18, glutathione S-transferase α, alpha-fetoprotein, arginase-1, osteopontin (OPN), sorbitol dehydrogenase, fatty acid binding protein, cadherin-5, macrophage colony-stimulating factor receptor (MCSFR), paraoxonase 1 (normalized to prothrombin protein), and leukocyte cell-derived chemotaxin-2.

In silico modeling to optimize interpretation of liver safety biomarkers in clinical trials.

Current strategies to delineate the risk of serious drug-induced liver injury associated with drugs rely on assessment of serum biomarkers that have been utilized for many decades. In particular, serum alanine aminotransferase and total bilirubin levels are typically used to assess hepatic integrity and function, respectively. Parallel measurement of these biomarkers is utilized to identify patients with drug-induced hepatocellular jaundice ("Hy's Law" cases) which carries at least a 10% risk of death or liver transplant.

Mechanisms of hepatotoxicity associated with the monocyclic β-lactam antibiotic BAL30072.

BAL30072 is a new monocyclic β-lactam antibiotic under development which provides a therapeutic option for the treatment of severe infections caused by multi-drug-resistant Gram-negative bacteria. Despite the absence of liver toxicity in preclinical studies in rats and marmosets and in single dose clinical studies in humans, increased transaminase activities were observed in healthy subjects in multiple-dose clinical studies. We, therefore, initiated a comprehensive program to find out the mechanisms leading to hepatocellular injury using HepG2 cells (human hepatocellular carcinoma cell line), HepaRG cells (inducible hepatocytes derived from a human hepatic progenitor cell line), and human liver microtissue preparations.

The transformation in biomarker detection and management of drug-induced liver injury.

Drug-induced liver injury (DILI) is a major concern for patients, care givers and the pharmaceutical industry. Interpretation of the serum biomarkers routinely used to detect and monitor DILI, which have not changed in almost 50 years, can be improved with recently proposed models employing quantitative systems pharmacology. In addition, several newer serum biomarkers are showing great promise.

Characterization of the Cytochrome P450 epoxyeicosanoid pathway in non-alcoholic steatohepatitis.

Non-alcoholic steatohepatitis (NASH) is an emerging public health problem without effective therapies. Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid into bioactive epoxyeicosatrienoic acids (EETs), which have potent anti-inflammatory and protective effects. However, the functional relevance of the CYP epoxyeicosanoid metabolism pathway in the pathogenesis of NASH remains poorly understood.

Beyond miR-122: Identification of MicroRNA Alterations in Blood During a Time Course of Hepatobiliary Injury and Biliary Hyperplasia in Rats.

Identification of circulating microRNAs for the diagnosis of liver injury and as an indicator of underlying pathology has been the subject of recent investigations. While several studies have been conducted, with particular emphasis on miR-122, the timing of miRNA release into the circulation and anchoring to tissue pathology has not been systematically evaluated. In this study, miRNA profiling was conducted over a time course of hepatobiliary injury and repair using alpha-naphthylisothiocyanate (ANIT) and a proprietary compound, FP004BA.

Sensitivity to hepatotoxicity due to epigallocatechin gallate is affected by genetic background in diversity outbred mice.

Consumer use of herbal and dietary supplements has recently grown in the United States and, with increased use, reports of rare adverse reactions have emerged. One such supplement is green tea extract, containing the polyphenol epigallocatechin gallate (EGCG), which has been shown to be hepatotoxic at high doses in animal models. The Drug-Induced Liver Injury Network has identified multiple patients who have experienced liver injury ascribed to green tea extract consumption and the relationship to dose has not been straightforward, indicating that differences in sensitivity may contribute to the adverse response in susceptible people.

A systems biology approach utilizing a mouse diversity panel identifies genetic differences influencing isoniazid-induced microvesicular steatosis.

Isoniazid (INH), the mainstay therapeutic for tuberculosis infection, has been associated with rare but serious hepatotoxicity in the clinic. However, the mechanisms underlying inter-individual variability in the response to this drug have remained elusive. A genetically diverse mouse population model in combination with a systems biology approach was utilized to identify transcriptional changes, INH-responsive metabolites, and gene variants that contribute to the liver response in genetically sensitive individuals.

Prostaglandin E(2) produced by the lung augments the effector phase of allergic inflammation.

Elevated PGE(2) is a hallmark of most inflammatory lesions. This lipid mediator can induce the cardinal signs of inflammation, and the beneficial actions of nonsteroidal anti-inflammatory drugs are attributed to inhibition of cyclooxygenase (COX)-1 and COX-2, enzymes essential in the biosynthesis of PGE(2) from arachidonic acid. However, both clinical studies and rodent models suggest that, in the asthmatic lung, PGE(2) acts to restrain the immune response and limit physiological change secondary to inflammation.

Allergic inflammation induces a persistent mechanistic switch in thromboxane-mediated airway constriction in the mouse.

Actions of thromboxane (TXA(2)) to alter airway resistance were first identified over 25 years ago. However, the mechanism underlying this physiological response has remained largely undefined. Here we address this question using a novel panel of mice in which expression of the thromboxane receptor (TP) has been genetically manipulated.