In Vitro Model for a Drug Assessment of Cytochrome P450 Family 3 Subfamily A Member 4 Substrates Using Human Induced Pluripotent Stem Cells and Genome Editing Technology
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ABSTRACT: In drug development, a system for predicting drug metabolism and drug-induced toxicity is necessary to ensure drug safety. Cytochrome P450 family 3 subfamily A member 4 (CYP3A4) is an important drug-metabolizing enzyme expressed in the liver and small intestine, and predicting CYP3A4-mediated drug metabolism and drug-induced toxicity is essential. We previously developed procedures to differentiate human induced pluripotent stem (iPS) cells into hepatocyte-like cells (HLCs) or intestinal epithelial-like cells (IECs) with a fetal phenotype as well as a highly efficient genome editing technology that could enhance the homologous recombination efficiency at any locus, including CYP3A4. By using human iPS cells and our genome editing technology, we generated CYP3A4-knockout (KO) iPS cell-derived HLCs and IECs for the evaluation of CYP3A4-mediated drug metabolism and drug-induced toxicity. CYP3A4 deficiency did not affect pluripotency and hepatic and intestinal differentiation capacities, and CYP3A4 activity was entirely eradicated by CYP3A4 KO. Off-target effects (e.g., inhibition of bile acid excretion) were hardly observed in CYP3A4-KO cells but were observed in CYP3A4 inhibitor-treated (e.g., ketoconazole) cells. To evaluate whether drug-induced hepatotoxicity and enterotoxicity could be predicted using our model, we exposed CYP3A4-KO HLCs and IECs to acetaminophen, amiodarone, desipramine, leflunomide, tacrine, and tolcapone and confirmed that these cells could predict CYP3A4-mediated toxicity. Finally, we examined whether the therapeutic effects of an anti-hepatitis C virus (HCV) drug metabolized by CYP3A4 would be predicted using our model. CYP3A4-KO HLCs were treated with asunaprevir (antiviral drug metabolized by CYP3A4) after HCV infection, and the anti-viral effect was indeed strengthened by CYP3A4 KO. Conclusion: We succeeded in generating a novel evaluation system for prediction of CYP3A4-mediated drug metabolism and drug-induced toxicity.
Project description:Cytochrome P450 family 2 subfamily C member 19 (CYP2C19), in liver, plays important roles in terms of drug metabolism. It is known that CYP2C19 poor metabolizers (PMs) lack CYP2C19 metabolic capacity. Thus, unexpected drug-induced liver injury or decrease of drug efficacy would be caused in CYP2C19 substrate-treated CYP2C19 PMs. However, it is difficult to evaluate the safety and effectiveness of drugs and candidate compounds for CYP2C19 PMs because there is currently no model for this phenotype. Here, using human iPS cells and our highly efficient genome editing and hepatocyte differentiation technologies, we generated CYP2C19-knockout human iPS cell-derived hepatocyte-like cells (CYP2C19-KO HLCs) as a novel CYP2C19 PM model for drug development and research. The gene expression levels of hepatocyte markers were similar between WT HLCs and CYP2C19-KO HLCs, suggesting that CYP2C19 deficiency did not affect the hepatic differentiation potency. We also examined CYP2C19 metabolic activity by measuring S-mephenytoin metabolites using LC-MS. The CYP2C19 metabolic activity was almost eliminated by CYP2C19 knockout. Additionally, we evaluated whether clopidogrel (CYP2C19 substrate)-induced liver toxicity could be predicted using our model. Unexpectedly, there was no significant difference in cell viability between clopidogrel-treated WT HLCs and CYP2C19-KO HLCs. However, the cell viability in clopidogrel- and ketoconazole (CYP3A4 inhibitor)-treated CYP2C19-KO HLCs was significantly enhanced as compared with that in clopidogrel- and DMSO-treated CYP2C19-KO HLCs. This result suggests that CYP2C19-KO HLCs can predict the clopidogrel-induced liver toxicity. We succeeded in generating CYP2C19 PM model cells using human iPS cells and genome editing technologies for pharmaceutical research.
Project description:Interindividual differences in hepatic metabolism, which are mainly due to genetic polymorphism in its gene, have a large influence on individual drug efficacy and adverse reaction. Hepatocyte-like cells (HLCs) differentiated from human induced pluripotent stem (iPS) cells have the potential to predict interindividual differences in drug metabolism capacity and drug response. However, it remains uncertain whether human iPSC-derived HLCs can reproduce the interindividual difference in hepatic metabolism and drug response. We found that cytochrome P450 (CYP) metabolism capacity and drug responsiveness of the primary human hepatocytes (PHH)-iPSHLCs were highly correlated with those of PHHs, suggesting that the PHH-iPS-HLCs retained donor-specific CYP metabolism capacity and drug responsiveness. We also demonstrated that the interindividual differences, which are due to the diversity of individual SNPs in the CYP gene, could also be reproduced in PHH-iPS-HLCs. We succeeded in establishing, to our knowledge, the first PHH-iPS-HLC panel that reflects the interindividual differences of hepatic drugmetabolizing capacity and drug responsiveness.
Project description:Human pluripotent stem cell (hPSC)-derived hepatocyte-like cells (HLCs) hold great promise for liver disease modeling, drug discovery, drug toxicity screens, or even regenerative therapies. Yet, several hurdles still need to be overcome, including among others decrease in the cost of goods to generate HLCs and automation of the differentiation process. We here describe that use of an automated liquid handling system results in highly reproducible HLC differentiation from hPSCs. This enabled us to screen 92 chemicals to replace expensive growth factors at each step of the differentiation protocol to reduce the cost of goods of the differentiation protocol by approximately 79%. In addition, we also evaluated several recombinant extracellular matrices (ECM) to replace Matrigel. We demonstrated that differentiation of hPSCs on Laminin-521 using an optimized small molecule combination resulted in HLCs that were transcriptionally identical to HLCs generated using current growth factor combinations. In addition, the HLCs created using the optimized small molecule combination also secreted similar concentrations of albumin and urea, and relatively low concentrations of alfa-fetoprotein (AFP), displayed similar CYP3A4 functionality and a similar drug toxicity susceptibility as HLCs generated with growth factor cocktails. The broad applicability of the new differentiation protocol was demonstrated for four different hPSC lines. This allowed the creation of a scalable, xeno-free, and cost-efficient hPSC-derived HLC culture, suitable for high throughput disease modeling and drug screenings, or even for the creation of HLCs for regenerative therapies.
Project description:Human induced pluripotent stem (iPS) cell-derived hepatocyte-like cells (HLCs) are expected to replace primary human hepatocytes (PHHs) as a new stable source of hepatocytes for pharmaceutical researches. However, HLCs have lower hepatic functions than PHHs, take a long time to be differentiated and cannot be prepared in large quantities due to not proliferating after their terminal differentiation. To overcome these problems, we have established hepatic organoids (iHOs) from HLCs. The iHOs could proliferate approximately 10^20-fold by more than 10 passages and expressed most hepatic genes higher than HLCs. Furthermore, in order to enable the widespread use of iHOs for in vitro drug discovery research, we have developed the two-dimensional culture protcol for them. Two-dimensional cutured iHOs (2D-iHOs) expressed most of major hepatocyte marker genes and proteins much higher than HLC, iHOs, and even PHHs. The 2D-iHOs had glycogen storage capacity, the capacity to uptake and release indocyanine green (ICG), albumin and urea secretion, and the capacity of bile canaliculi formation. Importantly, the 2D-iHOs had the activity of major drug-metabolizing enzymes and responded to hepatotoxic drugs, comparable to PHHs. Thus, 2D-iHOs overcome the limitation of the current models and promise to provide robust and reproducible pharmaceutical assays.
Project description:Induced pluripotent stem cells (iPSCs) are similar to embryonic stem cells and can be generated from somatic cells. We have generated episomal plasmid-based and integration-free iPSCs (E-iPSCs) from human fetal foreskin fibroblast cells (HFF1). E-iPSCs were fully characterized and their transcriptomes are more similar to that of hESCs (R2 = 0.9363) in comparison to viral-derived HFF1-iPSCs (R2 = 0.8176). We used an E-iPSC-line to model hepatogenesis in vitro. The differentiation of iPSCs into hepatocyte-like cells (HLCs) is a three-step process, from the undifferentiated E-iPSC to definitive endoderm (DE), hepatic endoderm (HE) and ultimately HLCs. The HLCs were characterized biochemically, i.e. glycogen storage, ICG uptake and release, UREA and bile acid production, as well as CYP3A4 activity. Ultra-structure analysis by electron microscopy revealed the presence of lipid and glycogen storage, tight junctions and bile canaliculi- all typical features of hepatocytes. Furthermore, the transcriptome of undifferentiated E-iPSC, DE, HE and HLCs were compared to that of fetal liver and primary human hepatocytes (PHH). K-means clustering identified 100 clusters which include developmental stage-specific groups of genes, e.g. OCT4 expression at the undifferentiated stage, SOX17 marking the DE stage, DLK and HNF6 the HE stage, HNF4a and Albumin is specific to HLCs, fetal liver and adult liver (PHH) stage. The lack of viral DNA integrations in these E-iPSCs endow them superior to viral-derived iPSCs for (i) modeling gene regulatory networks associated with hepatogenesis and gastrulation in general, (ii) toxicology studies and (iii) drug screening platforms.
Project description:Human stem cell-derived hepatocyte-like cells (HLCs) offer an attractive platform to study liver disease and to test drugs. However, despite their advantages over other hepatocyte culture systems, HLCs lack several in vivo characteristics including cell polarity, which is critical for proper hepatocyte biology. We report a stem cell-based differentiation protocol that uses transwell filters to generate columnar polarized HLCs with clearly defined basolateral and apical membranes separated by tight junctions. Unlike conventional HLCs, polarized HLCs secrete cargo directionally, similar to hepatocytes in vivo. This novel system provides a powerful tool to study hepatocyte biology, disease mechanisms, genetic variation, and drug metabolism in a more physiologically relevant setting.
Project description:Orally administered drugs are absorbed and metabolized in the intestine. In order to accurately predict pharmacokinetics in the intestine, it is essential to understand the intestinal expression profiles of genes related to drug absorption, distribution, metabolism, and excretion (ADME). However, in many previous studies, gene expression analysis in the intestine has been carried out using specimens from cancer patients. In this study, in order to obtain a more accurate gene expression profile, biopsy samples were collected from 14 patients under endoscopic observation and RNA-seq analysis was performed. Gene expression analysis of drug metabolizing enzymes (CYPs), non-CYP enzymes, nuclear receptors, drug conjugating enzymes (UGTs and SULTs), and apical and basolateral drug transporters was performed in biopsy samples from the duodenum, ileum, colon, and rectum. The proportions of the CYPs expressed in the ileum were 25% (CYP3A4), 19% (CYP2C18), and 14% (CYP3A5). CYP3A4 and CYP2C19 were highly expressed in the duodenum and ileum, but not in the colon and rectum. In the ileum, apical transporters such as P-gp, PEPT1, BCRP, MRP2, and ASBT were strongly expressed, and the expression levels of P-gp and ASBT in the ileum were higher than those in other regions. In the ileum, basolateral transporters such as OSTα, OSTβ, and MRP3 were strongly expressed. Furthermore, we identified specific markers for the duodenum, ileum, colon, and rectum by conducting comprehensive gene expression analysis. We succeeded in obtaining gene expression profiles of drug ADME-related genes in vivo human intestinal epithelial cells. We expect that this information would be useful for accurate prediction of the pharmacokinetics of oral drugs.
Project description:Various adaptive cellular stress response pathways are critical in the pathophysiology of liver disease and drug-induced liver injury. Human-induced pluripotent stem cell (hiPSC)-derived hepatocyte-like cells (HLCs) provide a promising tool to study cellular stress response pathways, but in this context there is limited insight on how HLCs compare to primary human hepatocytes (PHH). Here, we systematically compared the activation of four different stress pathways in PHH, HepG2 liver cancer cells, hiPSCs and different stages within the differentiation towards HLCs (definitive endoderm, hepatoblast, immature hepatocytes and HLCs). We exposed all different cell types in a concentration response to four different compounds that specifically activate the oxidative stress response (diethyl-maleate), unfolded protein response (tunicamycin), DNA damage response (cisplatin) and inflammatory signalling (TNF). We used targeted RNA-sequencing to map concentration response transcriptional similarities and differences using bench-mark concentration modelling for the various stress responses in the different test systems. We observed that HLCs are more sensitive to oxidative stress than PHH showing activation at ten-fold lower concentrations and induce a strong anti-oxidant response. Although similar UPR gene sets were activated in HLCs compared to PHH, PHH were about ten times more sensitive. Furthermore, HLCs were highly sensitive to inflammation conditions similar to HepG2 cells and in sharp contrast to hiPSC, which showed hardly any response. On the contrary, hiPSC and HepG2 were highly sensitive to DNA damage signalling while HLCs resisted a strong p53 DNA damage response upon exposure. Overall, the data indicate that despite limitation in full hepatocyte maturation, HLCs did gain specific adaptive cellular stress response networks that mimic those of PHHs.
Project description:Hepatocyte-like cells derived from human pluripotent stem cells (hPSC-HLCs) offer an alternative to primary hepatocytes commonly used for drug screenings and toxicological tests. However, these cells do not have hepatic functions comparable to those of hepatocytes in vivo due to insufficient hepatic differentiation. Here we showed that the hepatic functions of hPSC-HLCs were facilitated by applying physiological liver temperatures during hepatic differentiation. We identified the optimal temperature by treating HLCs derived from H9 human embryonic stem cells (hESC-HLCs) at 39 °C; the 42 °C treatment caused significantly greater cell death than the 39 °C treatment. We confirmed the improvement of hepatic functions, such as albumin secretion, cytochrome P450 3A activity, and collagen production, without severe cell damage. In combination with existing hepatic differentiation protocols, the method proposed here may further improve hepatic functions for hPSCs and lead to the realization of drug discovery efforts and drug toxicological tests.
Project description:Human pluripotent stem cells (hPSCs) can differentiate into all cell types in the body that may replace current cell sources applied in regenerative medicine, cell therapy, drug discovery and development and general research. Human PSC-derived hepatocyte-like cells (HLCs) have the potential to replace primary hepatocytes and other cell models applied in liver disease treatment and drug discovery and development. These cells share many features with their in vivo counterparts however, the generation of fully functional hPSC-derive HLCs is still lacking, which prevent their application in the previously mentioned fields. This study followed the transcriptome dynamics during the differentiation of hPSC-derived HLCs at definitive endoderm, hepatoblast, early HLC and late HLC developmental stages and the controls hPSCs and human liver tissues which consists of at least 70% hepatocytes. The aim is to reveal expression deviations between hPSC-derived hepatocytes and their in vivo counterparts that may contribute to the modification of differentiation protocols to generate fully functional hepatocytes.