Project description:Drug-induced hepatotoxicity is a leading cause of attrition of candidate drugs in drug development. Therefore new screening methods are necessary which predict these hazards more accurate and earlier in the drug development process. Of all in vitro hepatotoxicity models, primary human hepatocytes are considered as 'the gold standard'. However, the use of these hepatocytes is hindered by their scarcity and major inter-individual variation. These limitations may be overcome with use of primary mouse hepatocytes. Within this context changes in protein expressions in primary mouse hepatocytes, after exposure to cyclosporin A were studied using differential gel electrophoresis. Thereafter, the mRNA expression levels of these deregulated proteins from cyclosporin A-treated cells were analyzed. Cyclosporin A induced ER stress and altered the ER-Golgi transport, which may alter vesicle mediated transport and protein secretion. Moreover are the differentially expressed proteins observed upon challenge by cyclosporin A, associated with cholestatic mechanisms. For each biological experiment, one hybridization was conducted and one sample per array. In total, 6 arrays were used for 2 different conditions (Csa or control at 48 hours).
Project description:Drug-induced hepatotoxicity is a leading cause of attrition of candidate drugs in drug development. Therefore new screening methods are necessary which predict these hazards more accurate and earlier in the drug development process. Of all in vitro hepatotoxicity models, primary human hepatocytes are considered as 'the gold standard'. However, the use of these hepatocytes is hindered by their scarcity and major inter-individual variation. These limitations may be overcome with use of primary mouse hepatocytes. Within this context changes in protein expressions in primary mouse hepatocytes, after exposure to cyclosporin A were studied using differential gel electrophoresis. Thereafter, the mRNA expression levels of these deregulated proteins from cyclosporin A-treated cells were analyzed. Cyclosporin A induced ER stress and altered the ER-Golgi transport, which may alter vesicle mediated transport and protein secretion. Moreover are the differentially expressed proteins observed upon challenge by cyclosporin A, associated with cholestatic mechanisms.
Project description:Drug-induced hepatotoxicity is still one of the main reasons for drug attrition; therefore, there is an urgent need for more predictive models to identify the toxic potential of new drug candidates. Here, transcriptomic data from short- and long-term cultured primary human hepatocytes exposed to four pharmaceuticals, namely ibuprofen, chlorpromazine, cyclosporine A and amiodarone was analysed.
Project description:Human liver organoids, an in vitro 3D culture system to recapitulate biological tissue, are expected to be used for drug discovery. However, Matrigel, the most widely used extracellular matrix for organoid culture, has concerns about safety and reproducibility since it is murine-derived. Morever, low hepatic functions of human liver organoids compared to primary human hepatocytes is considered a challenge. Herein, we attempted to culture human liver organoids, established from primary (cryopreserved) human hepatocytes (PHH), using HYDROX, a chemically defined 3D nanofiber. While proliferative capacity of human liver organoids was lost by HYDROX-culture, the gene expression level of a hepatocyte marker CYP3A4 and the CYP3A4 metabolic activity in HYDROX-cultured liver organoids were significantly improved, comparable to those of PHH. HYDROX-cultured liver organoids when treated with hepatotoxic drugs such as acetaminophen showed similar cell viability to that of PHH, suggesting that HYDROX-cultured liver organoids could be applied to drug-induced hepatotoxicity test. Furthermore, HYDROX-cultured liver organoids maintained its functions for up to 35 days and could be used to estimate chronic drug-induced hepatotoxicity such as those of fialuridine. Our findings demonstrated that human liver organoids obtained high liver functions by HYDROX-culture, meaning that HYDROX could contribute to drug discovery as a novel biomaterial.
Project description:Pazopanib is a drug with idiosyncratic hepatotoxicity risk. Analysis of gene expression changes after exposing hepatocytes can indicate effects on specific biological pathways and potential mechanisms of hepatotoxicity. HLCs derived from patient-specific iPSCs were treated with pazopanib to identify both drug-related global effects and patient-specific effects
Project description:Drug induced liver injury (DILI) is still a major reason for drug attrition during clinical trials and market-withdrawal of already approved drugs. DILI is difficult to predict in animal models, hence more suitable screening methods are needed to predict adverse effects in human. Here, transcriptomic data from short- and long-term cultured primary human hepatocytes exposed to the human hepatotoxin Chlorpromazine was analysed.
Project description:Primary human hepatocytes (PHH) are a main instrument in drug metabolism research and in the prediction of drug-induced phase I/II enzyme induction in humans. The HepG2 liver-derived cell line is commonly used as a surrogate for human hepatocytes, but their use in ADME and toxicity studies can be limited because of lowered basal levels of metabolizing enzymes. Despite their widespread use, the transcriptome of HepG2 cells compared to PHH is not well characterized. In this study, microarray analysis was conducted to ascertain the differences and similarities in mRNA expression between HepG2 cells and human hepatocytes before and after exposure to a panel of fluoroquinolone compounds. Comparison of the naïve HepG2 cell and PHH transcriptomes revealed a substantial number of basal gene expression differences. When HepG2 cells were dosed with a series of fluoroquinolones, trovafloxacin, which has been associated with human idiosyncratic hepatotoxicity, induced substantially more gene expression changes than the other quinolones, similar to previous observations with PHH. While TVX-treatment resulted in many gene expression differences between HepG2 cells and PHH, there were also a number of TVX-induced commonalities, including genes involved in RNA processing and mitochondrial function. Taken together, these results provide insight for interpretation of results from drug metabolism and toxicity studies conducted with HepG2 cells in lieu of PHH, and could provide further insight into the mechanistic evaluation of TVX-induced hepatotoxicity. Keywords: Cell Type Comparison
Project description:Drug-induced liver injury (DILI), especially acetaminophen overdose, is the leading cause of acute liver failure. Pregnane X receptor (PXR) is a nuclear receptor and the master regulator of drug metabolism. Aberrant activation of PXR plays a pathogenic role in the acetaminophen hepatotoxicity. Here, we aimed to examine the PXR S-nitrosylation (SNO) in response to acetaminophen. We found that PXR was S-nitrosylated in hepatocytes and the mouse livers after exposure to acetaminophen or S-nitrosoglutathione (GSNO). Mass-spectrometry and site-directed mutagenesis identified the cysteine 307 as the primary residue for SNO-modification. In hepatocytes, SNO suppressed both agonist (rifampicin and SR12813)-induced and constitutively active PXR (VP-PXR) activations. Furthermore, in acetaminophen overdosed mouse livers, PXR protein was decreased at the centrilobular regions overlapping with increased SNO. In PXR-deficient (PXR-/-) mice, replenishing the livers with the SNO-deficient PXR significantly aggravated hepatic necrosis and apoptosis, increased HMGB1 release, and exacerbated liver injury and inflammation. Particularly, we demonstrated that S-nitrosoglutathione reductase (GSNOR) inhibitor N6022 promoted hepatoprotection by increasing the levels of PXR S-nitrosylation. In conclusion, PXR is post-translationally modified by S-nitrosylation in hepatocytes in response to acetaminophen. This modification mitigated the acetaminophen-induced PXR hyperactivity. It may serve as a new target for therapeutical intervention.
Project description:The zebrafish is as a powerful vertebrate model system for modeling human disease including liver pathology. In ZFE, hepatic responses can be expected after exposure to hepatotoxicants, because hepatocytes are present from 36-hpf and at 72-hpf the liver is fully functioning. These characteristics make the whole ZFE an attractive alternative model for compound-induced hepatotoxicity screening. Therefore, the main objective of this study is to further strengthen the applicability of whole ZFE as an alternative model for hepatotoxicity testing, with a special focus on the ability to identify gene expression responses in whole ZFE that are suggestive of hepatotoxicity. Deep sequence technology is applied to assess whether hepatotoxicity-specific transcripts that are identified in livers of hepatotoxicant treated adult zebrafish can be detected in whole ZFE as well.