Showing papers by "B.K. Park published in 2015"

Comprehensive microRNA profiling in acetaminophen toxicity identifies novel circulating biomarkers for human liver and kidney injury

Abstract: Our objective was to identify microRNA (miRNA) biomarkers of drug-induced liver and kidney injury by profiling the circulating miRNome in patients with acetaminophen overdose. Plasma miRNAs were quantified in age- and sex-matched overdose patients with (N = 27) and without (N = 27) organ injury (APAP-TOX and APAP-no TOX, respectively). Classifier miRNAs were tested in a separate cohort (N = 81). miRNA specificity was determined in non-acetaminophen liver injury and murine models. Sensitivity was tested by stratification of patients at hospital presentation (N = 67). From 1809 miRNAs, 75 were 3-fold or more increased and 46 were 3-fold or more decreased with APAP-TOX. A 16 miRNA classifier model accurately diagnosed APAP-TOX in the test cohort. In humans, the miRNAs with the largest increase (miR-122-5p, miR-885-5p, miR-151a-3p) and the highest rank in the classifier model (miR-382-5p) accurately reported non-acetaminophen liver injury and were unaffected by kidney injury. miR-122-5p was more sensitive than ALT for reporting liver injury at hospital presentation, especially combined with miR-483-3p. A miRNA panel was associated with human kidney dysfunction. In mice, miR-122-5p, miR-151a-3p and miR-382-5p specifically reported APAP toxicity - being unaffected by drug-induced kidney injury. Profiling of acetaminophen toxicity identified multiple miRNAs that report acute liver injury and potential biomarkers of drug-induced kidney injury.

Physiological, pharmacological and toxicological considerations of drug-induced structural cardiac injury

Abstract: The incidence of drug-induced structural cardiotoxicity, which may lead to heart failure, has been recognized in association with the use of anthracycline anti-cancer drugs for many years, but has also been shown to occur following treatment with the new generation of targeted anti-cancer agents that inhibit one or more receptor or non-receptor tyrosine kinases, serine/threonine kinases as well as several classes of non-oncology agents. A workshop organized by the Medical Research Council Centre for Drug Safety Science (University of Liverpool) on 5 September 2013 and attended by industry, academia and regulatory representatives, was designed to gain a better understanding of the gaps in the field of structural cardiotoxicity that can be addressed through collaborative efforts. Specific recommendations from the workshop for future collaborative activities included: greater efforts to identify predictive (i) preclinical; and (ii) clinical biomarkers of early cardiovascular injury; (iii) improved understanding of comparative physiology/pathophysiology and the clinical predictivity of current preclinical in vivo models; (iv) the identification and use of a set of cardiotoxic reference compounds for comparative profiling in improved animal and human cellular models; (v) more sharing of data (through publication/consortia arrangements) on target-related toxicities; (vi) strategies to develop cardio-protective agents; and (vii) closer interactions between preclinical scientists and clinicians to help ensure best translational efforts.

Adaptation to acetaminophen exposure elicits major changes in expression and distribution of the hepatic proteome

Abstract: Acetaminophen overdose is the leading cause of acute liver failure. One dose of 10-15 g causes severe liver damage in humans, whereas repeated exposure to acetaminophen in humans and animal models results in autoprotection. Insight of this process is limited to select proteins implicated in acetaminophen toxicity and cellular defence. Here we investigate hepatic adaptation to acetaminophen toxicity from a whole proteome perspective, using quantitative mass spectrometry. In a rat model, we show the response to acetaminophen involves the expression of 30% of all proteins detected in the liver. Genetic ablation of a master regulator of cellular defence, NFE2L2, has little effect, suggesting redundancy in the regulation of adaptation. We show that adaptation to acetaminophen has a spatial component, involving a shift in regionalisation of CYP2E1, which may prevent toxicity thresholds being reached. These data reveal unexpected complexity and dynamic behaviour in the biological response to drug-induced liver injury.

The chemical, genetic and immunological basis of idiosyncratic drug–induced liver injury:

Abstract: Idiosyncratic drug reactions can be extremely severe and are not accounted for by the regular pharmacology of a drug. Thus, the mechanism of idiosyncratic drug-induced liver injury (iDILI), a phenomenon that occurs with many drugs including β-lactams, anti-tuberculosis drugs and non-steroidal anti-inflammatories, has been difficult to determine and remains a pressing issue for patients and drug companies. Evidence has shown that iDILI is multifactorial and multifaceted, which suggests that multiple cellular mechanisms may be involved. However, a common initiating event has been proposed to be the formation of reactive drug metabolites and covalently bound adducts. Although the fate of these metabolites are unclear, recent evidence has shown a possible link between iDILI and the adaptive immune system. This review highlights the role of reactive metabolites, the recent genetic innovations which have provided molecular targets for iDILI, and the current literature which suggests an immunological basis for iDILI.

HLA‐DQ allele‐restricted activation of nitroso sulfamethoxazole‐specific CD4‐positive T lymphocytes from patients with cystic fibrosis

Abstract: BACKGROUND For certain HLA allele-associated drug hypersensitivity reactions, the parent drug has been shown to associate directly with the risk allele. In other forms of hypersensitivity, HLA risk alleles have not been identified and T cells are activated in an allele unrestricted manner. Chemically reactive drug metabolites bind to multiple proteins; thus, it is assumed that the derived peptide antigens interact with a number of HLA molecules to activate T cells; however, HLA restriction of the drug metabolite-specific T-cell response has not been studied. OBJECTIVE To utilize T cells from sulfamethoxazole (SMX) hypersensitive patients with cystic fibrosis to examine the HLA molecules that interact with nitroso SMX (SMX-NO)-derived antigens. METHODS T-cell clones were generated from 4 hypersensitive patients. Drug-specific proliferative responses and cytokine secretion were measured. Anti-human class I and class II antibodies were used to analyse HLA restriction. Antigen-presenting cells expressing different HLA molecules were used to determine the alleles involved in the presentation of SMX-NO-derived antigens to T cells. RESULTS A total of 976 clones were tested for SMX-NO reactivity. Thirty-nine CD4+ clones were activated with SMX-NO and found to proliferate and secrete cytokines. The SMX-NO-specific response was blocked with an antibody against HLA-DQ. SMX-NO-specific responses were detected with antigen-presenting cells expressing HLA-DQB1*05:01 (patient 1) and HLA-DQB1*02:01 (patient 2), but not other HLA-DQB1 alleles. CONCLUSION AND CLINICAL RELEVANCE HLA-DQ plays an important role in the activation of SMX-NO-specific CD4+ T cells. Detection of HLA-DQ allele-restricted responses suggests that T cells are activated by a limited repertoire of SMX-NO-modified peptides.

Evaluation of a novel tissue stabilization gel to facilitate clinical sampling for translational research in surgical trials

Abstract: Background The aim was to establish the feasibility of using a tissue stabilization gel (Allprotect™) as an alternative to liquid nitrogen to facilitate collection of clinical samples for translational research. Methods Tumour samples from patients undergoing surgery for primary or metastatic colorectal cancer were either snap-frozen in liquid nitrogen or stored in Allprotect™ under a number of different conditions. Sample integrity was compared across different storage conditions by assessing biomolecule stability and function. DNA quality was assessed spectrophotometrically and by KRas genotyping by pyrosequencing. Total RNA retrieval was determined by nanodrop indices/RNA integrity numbers, and quality assessed by reverse transcription–PCR for two representative genes (high-mobility group box 1, HMGB1; carboxylesterase 1, CES1) and two microRNAs (miR122 and let7d). Western blot analysis of HMGB1 and CES1 was used to confirm protein expression, and the metabolic conversion of irinotecan to its active metabolite, SN-38, was used to assess function. Results Under short-term storage conditions (up to 1 week) there was no apparent difference in quality between samples stored in Allprotect™ and those snap-frozen in liquid nitrogen. Some RNA degradation became apparent in tissue archived in Allprotect™ after 1 week, and protein degradation after 2 weeks. Conclusion In hospitals that do not have access to liquid nitrogen and –80°C freezers, Allprotect™ provides a suitable alternative for the acquisition and stabilization of clinical samples. Storage proved satisfactory for up to 1 week, allowing transfer of samples without the need for specialized facilities. Surgical relevance Access to clinical material is a fundamental component of translational research that requires significant infrastructure (research personnel, liquid nitrogen, specialized storage facilities). The aim was to evaluate a new-to-market tissue stabilization gel (Allprotect™), which offers a simple solution to tissue preservation without the need for complex infrastructure. Allprotect™ offers comparable DNA, RNA and protein stabilization to tissue snap-frozen in liquid nitrogen for up to 1 week. Degradation of biomolecules beyond this highlights its role as a short-term tissue preservative. Allprotect™ has the potential to increase surgeon participation in translational research and surgical trials requiring tissue collection.