Utility of human induced pluripotent stem cell-derived small intestinal epithelial cells for pharmacokinetic, toxicological, and immunological studies.

The small intestine, which plays a crucial role in the absorption and metabolism of drugs and foods, serves as a target organ for drug-induced toxicity and immune interactions with functional foods and intestinal bacteria. Current alternative models of the human small intestine, such as Caco-2 cells and experimental animals, have limitations due to variations in the expression levels of metabolic enzymes, transporters, and receptors. This study presents investigations into the utility of human induced pluripotent stem cell-derived small intestinal epithelial cells (hiSIECs) for pharmacokinetic, toxicological, and immunological studies, respectively. While hiSIECs displayed small intestinal epithelial cell characteristics and barrier function, they demonstrated pharmacokinetic properties such as cytochrome P450 3A4/5 activity equivalent to human primary enterocytes and stable P-glycoprotein activity. These cells also demonstrated potential for assessing two forms of intestinal toxicity caused by anticancer drugs and gamma-secretase inhibitors, displaying immune responses mediated by toll-like and fatty acid receptors while serving as an inflammatory gut model through the addition of tumor necrosis factor alpha and interferon gamma. Overall, hiSIECs hold promise as an in vitro model for assessing pharmacokinetics, toxicity, and effects on the intestinal immunity of pharmaceuticals, functional foods, supplements, and intestinal bacteria.

Effect of Anagliptin on Vascular Injury in the Femoral Artery of Type 2 Diabetic Rats.

Patients with diabetes mellitus (DM) often experience complications such as peripheral arterial disease (PAD), which is thought to be caused by vascular damage resulting from increased oxidative stress. Dipeptidyl peptidase-4 inhibitors have been reported to reduce oxidative stress, although the exact mechanism remains unclear. This study aimed to investigate the impact of long-term (6 weeks) anagliptin treatment at a dose of 200 mg/kg/d against oxidative stress in the femoral artery of Otsuka Long-Evans Tokushima Fatty (OLETF) rats using a well-established animal model for type 2 DM. Serum toxic advanced glycation end-products concentrations and blood glucose levels after glucose loading were significantly elevated in OLETF rats compared to Long-Evans Tokushima Otsuka (LETO) rats but were significantly suppressed by anagliptin administration. Plasma glucagon-like peptide-1 concentrations after glucose loading were significantly increased in anagliptin-treated rats. Superoxide production and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in femoral arteries were significantly increased in OLETF rats compared to LETO rats but were significantly decreased by anagliptin administration. The expressions of NADPH oxidase components (p22phox in the intima region and p22phox and gp91phox in the media region) in the femoral artery were significantly increased in OLETF rats compared to LETO rats but were significantly suppressed by anagliptin administration. Furthermore, the femoral artery showed increased wall thickness in OLETF rats compared to LETO rats, but anagliptin administration reduced the thickening. This study suggests that long-term anagliptin administration can reduce oxidative stress in femoral arteries and improve vascular injury.

New Maintenance Culture Method for Intestinal Stem Cells Derived from Human Induced Pluripotent Stem Cells.

Most orally administered drugs exert their effects after being absorbed in the small intestine. Therefore, new drugs must undergo nonclinical pharmacokinetic evaluations in the small intestine. Enterocytes derived from human induced pluripotent stem cells (hiPSCs) are expected to be used in the evaluation system, as they reflect human intestinal characteristics more accurately; moreover, several differentiation protocols are available for these cells. However, enterocytes derived from hiPSCs have drawbacks such as time, cost, and lot-to-lot differences. Hence, to address these issues, we attempted to maintain hiPSC-derived intestinal stem cells (ISCs) that can differentiate into various intestinal cells by regulating various pathways. Although our previous attempt was partly successful, the drawbacks of elevated cost and complicated handling remained, because more than 10 factors (A 83-01, CHIR99021, epidermal growth factor, basic fibroblast growth factor, SB202190, nicotinamide, N-acetylcysteine, valproic acid, Wnt3a, R-spondin 1, and noggin) are needed to maintain ISCs. Therefore, in this study, we successfully maintained ISCs using only five factors, including growth factors. Moreover, we generated not only enterocytes but also intestinal organoids from the maintained ISCs. Thus, our novel findings provided a time-saving and cost-effective culture method for enterocytes derived from hiPSCs.

Krüppel-like Factor-4-Mediated Macrophage Polarization and Phenotypic Transitions Drive Intestinal Fibrosis in THP-1 Monocyte Models In Vitro.

Background and Objectives: Despite the fact that biologic drugs have transformed inflammatory bowel disease (IBD) treatment, addressing fibrosis-related strictures remains a research gap. This study explored the roles of cytokines, macrophages, and Krüppel-like factors (KLFs), specifically KLF4, in intestinal fibrosis, as well as the interplay of KLF4 with various gut components. Materials and Methods: This study examined macrophage subtypes, their KLF4 expression, and the effects of KLF4 knockdown on macrophage polarization and cytokine expression using THP-1 monocyte models. Co-culture experiments with stromal myofibroblasts and a conditioned medium from macrophage subtype cultures were conducted to study the role of these cells in intestinal fibrosis. Human-induced pluripotent stem cell-derived small intestinal organoids were used to confirm inflammatory and fibrotic responses in the human small intestinal epithelium. Results: Each macrophage subtype exhibited distinct phenotypes and KLF4 expression. Knockdown of KLF4 induced inflammatory cytokine expression in M0, M2a, and M2c cells. M2b exerted anti-fibrotic effects via interleukin (IL)-10. M0 and M2b cells showed a high migratory capacity toward activated stromal myofibroblasts. M0 cells interacting with activated stromal myofibroblasts transformed into inflammatory macrophages, thereby increasing pro-inflammatory cytokine expression. The expression of IL-36α, linked to fibrosis, was upregulated. Conclusions: This study elucidated the role of KLF4 in macrophage polarization and the intricate interactions between macrophages, stromal myofibroblasts, and cytokines in experimental in vitro models of intestinal fibrosis. The obtained results may suggest the mechanism of fibrosis formation in clinical IBD.

Simultaneous Evaluation of Membrane Permeability and UDP-Glucuronosyltransferase-Mediated Metabolism of Food-Derived Compounds Using Human Induced Pluripotent Stem Cell-Derived Small Intestinal Epithelial Cells.

Pharmacokinetic prediction after oral ingestion is important for quantitative risk assessment of food-derived compounds. To evaluate the utility of human intestinal absorption prediction, we compared the membrane permeability and metabolic activities of human induced pluripotent stem cell-derived small intestinal epithelial cells (hiPSC-SIECs) with Caco-2 cells or human primary enterocytes (hPECs). We found that membrane permeability in hiPSC-SIECs had better predictivity than that in Caco-2 cells against 21 drugs with known human intestinal availability (r = 0.830 and 0.401, respectively). Membrane permeability in hiPSC-SIECs was only 0.019-0.25-fold as compared with that in Caco-2 cells for 7 in 15 food-derived compounds, primarily those that were reported to undergo glucuronidation metabolism. The metabolic rates of the glucuronide conjugate were similar or higher in hiPSC-SIECs as compared with hPECs but lower in Caco-2 cells. Expression levels of UDP-glucuronosyltransferase (UGT) isoform mRNA in hiPSC-SIECs were similar or higher as compared with hPECs. Therefore, hiPSC-SIECs could be a useful tool for predicting human intestinal absorption to simultaneously evaluate membrane permeability and UGT-mediated metabolism. SIGNIFICANCE STATEMENT: Gastrointestinal absorption is an important step for predicting the internal exposure of food-derived compounds. This research revealed that human induced pluripotent stem cell-derived small intestinal cells (hiPSC-SIECs) had better predictivity of intestinal availability than Caco-2 cells; furthermore, the metabolic rates of UDP-glucuronosyltransferase (UGT) substrates of hiPSC-SIECs were closer to those of human primary enterocytes than those of Caco-2 cells. Therefore, hiPSC-SIECs could be a useful tool for predicting human intestinal absorption to simultaneously evaluate membrane permeability and UGT-mediated metabolism.

Protective Effect of Irsogladine against Aspirin-Induced Mucosal Injury in Human Induced Pluripotent Stem Cell-Derived Small Intestine.

Background and Objectives: Acetylsalicylic acid (ASA) is widely used for preventing cerebrovascular and cardiovascular diseases. Gastrointestinal (GI) tract injury is one of the major complications of aspirin use, potentially leading to severe GI bleeding. However, no drugs for preventing aspirin-induced small intestinal injury have been developed. The aim of this study was to establish a human experimental model for investigating aspirin-induced small intestinal mucosal injury. In addition, we evaluated the protective effect of Irsogladine against aspirin-induced small intestinal mucosal injury using human induced pluripotent stem cell-derived 2D monolayer crypt-villus structural small intestine (2D-hiPSC-SI). Materials and Methods: Human iPS cell-derived intestinal organoids were seeded and cultured in Air-liquid interface. The permeability of 2D-hiPSC-SI was evaluated using Lucifer yellow. Changes in structure and mucosal permeability of 2D-hiPSC-SI after addition of aspirin were confirmed over time, and changes in intestinal epithelium-related markers were evaluated by real-time qPCR and Immunofluorescence staining. The effect of Irsogladine on prevention of aspirin mucosal injury was examined by adding Irsogladine to the culture medium. Results: Cultured 2D-hiPSC-SI showed multi-lineage differentiation into small intestinal epithelium comprised of absorptive cells, goblet cells, enteroendocrine cells, and Paneth cells, which express CD10, MUC2, chromogranin A, and lysozyme, respectively. RNA in situ hybridization revealed intestinal stem cells that express Lgr5. ASA administration induced an increase in the mucosal permeability of 2D-hiPSC-SI. ASA-injured 2D-hiPSC-SI showed decreased mRNA expression of multi-lineage small intestinal cell markers as well as intestinal stem cell marker Lgr5. Administration of Irsogladine on the basal side of the 2D-hiPSC-SI resulted in significant increases in Mki67 and Muc2 mRNA expression by 2D-hiPSCs at 48 h compared with the control group. Administration of 400 µg/mL Irsogladine to the ASA-induced small intestinal injury model resulting in significantly decreased mucosal permeability of 2D-hiPSC-SI. In immunofluorescence staining, Irsogladine significantly increased the fluorescence intensity of MUC2 under normal conditions and administration of 400 µg/mL ASA. Conclusions: we established a novel ASA-induced small intestinal injury model using human iPSC-derived small intestine. Irsogladine maintains mucosal permeability and goblet cell differentiation against ASA-induced small intestinal injury.

Application of Human Induced Pluripotent Stem Cell-Derived Intestinal Organoids as a Model of Epithelial Damage and Fibrosis in Inflammatory Bowel Disease.

Inflammatory bowel disease, which typically manifests as Crohn's disease and ulcerative colitis, is caused by the abnormal production of cytokines such as tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-ß. These cytokines damage intestinal epithelial cells and trigger fibrosis, respectively, for which the current in vitro models have many limitations. Therefore, we tested whether human induced pluripotent stem cell-derived intestinal organoids (HiOs) can mimic inflammatory bowel disease (IBD), and whether such a model is suitable for drug screening. HiOs were treated with TNF-α and TGF-ß to construct mucosal damage and fibrosis models. TNF-α diminished the mRNA expression of intestinal epithelial cell and goblet cell markers in HiOs. TNF-α also induced epithelial cell damage and degradation of tight junctions but not in the presence of infliximab, an antibody used in the clinic to deplete TNF-α. Furthermore, permeation of the non-absorbable marker FD-4 was observed in HiOs treated with TNF-α or ethylene glycol tetraacetic acid (EGTA), but not in the presence of infliximab. In contrast, TNF-α and TGF-ß induced mRNA expression of mesenchymal and fibrosis markers, as well as epithelial-mesenchymal transition. SB431542, a TGF-ß inhibitor, significantly reversed these events. The data indicate that HiOs mimic mucosal damage and fibrosis due to IBD and are thus suitable models for drug screening.

Isolation of induced pluripotent stem cell-derived endothelial progenitor cells from sac-like structures.

Transplanted endothelial progenitor cells (EPCs) repair blood vessels and exert regenerative effects on disorders such as lower limb ischemia. EPCs serve as a model for pathophysiological and pharmacokinetic studies, which is important for drug discovery. However, primary human EPCs are phenotypically unstable, which limits their clinical utility. Therefore, we employed human induced pluripotent stem (iPS) cells to circumvent this problem. Here we focused on human iPS cell-derived sac-like structures (iPS-sacs), which contain endothelial lineage cells and hematopoietic lineage cells. Previous studies isolated only hematopoietic lineage cells from iPS-sacs. Therefore, here we attempted to isolate EPCs. However, iPS-sacs generated by a published protocol did not contain sufficient EPCs. Therefore, to generate iPS-sacs highly enriched in EPCs, we added the glycogen synthase kinase 3 beta (GSK3ß) inhibitor CHIR-99021 to the culture medium early during differentiation. The cells rapidly differentiated into mesoderm to yield abundant EPCs, and CHIR-99021 increased the proportion of EPCs contained in iPS-sacs. EPCs, which were purified using anti-platelet endothelial cell adhesion molecule (PECAM1) antibody-conjugated beads, expressed markers of immature endothelial cells. Purified EPCs formed tube-like structures and incorporated acetylated low density lipoprotein (Ac-LDL), reflecting endothelial phenotypes. The simple method described here will likely improve regenerative medicine and facilitate basic studies on the endothelial lineage.

Contribution of rat embryonic stem cells to xenogeneic chimeras in blastocyst or 8-cell embryo injection and aggregation.

The ultimate goal of regenerative medicine is the transplantation of a target organ generated by the patient's own cells. Recently, a method of organ generation using pluripotent stem cells (PSCs) and blastocyst complementation was reported. This approach is based on chimeric animal generation using an early embryo and PSCs, and the contribution of PSCs to the target organ is key to the method's success. However, the contribution rate of PSCs in target organs generated by different chimeric animal generation methods remains unknown. In this study, we used 8-cell embryo aggregation, 8-cell embryo injection, and blastocyst injection to generate interspecies chimeric mice using rat embryonic stem (ES) cells and then investigated the differences in the contribution rate of the rat ES cells. The rate of chimeric mouse generation was the highest using blastocyst injection, followed in order by 8-cell embryo injection and 8-cell embryo aggregation. However, the contribution rate of rat ES cells was the highest in chimeric neonates generated by 8-cell embryo injection, and the difference was statistically significant in the liver. Live functionality was confirmed by analyzing the expression of rat hepatocyte-derived drug-metabolizing enzyme. Collectively, these findings indicate that the 8-cell embryo injection method is the most suitable for generation of PSC-derived organs via chimeric animal generation, particularly for the liver.

Effect of Celecoxib on Differentiation of Human Induced Pluripotent Stem Cells into Hepatocytes Involves STAT5 Activation.

The liver abundantly expresses various drug-metabolizing enzymes and, thus, plays a central role in drug metabolism. In this regard, cytochrome P450 (CYP) is responsible for drug metabolism in the liver. Therefore, since CYP3A4 accounts for approximately 30% of the CYPs, the prediction of hepatic CYP3A4-mediated pharmacokinetics is essential for drug development. Human induced pluripotent stem cell-derived hepatocytes (hiHep) have become a major model of drug metabolism in drug development studies. However, drug metabolizing activities, such as those involving CYP3A4, are lower in hiHep than in human primary hepatocytes (HPHs). Recently, it was revealed that celecoxib upregulates the expression of CYPs to normal levels through the activation of signal transducer and transcriptional activation factor 5 (STAT5). Therefore, we investigated whether celecoxib treatment could normalize the low drug metabolism activities in hiHep. The mRNA expression levels of hepatic markers [asialoglycoprotein receptor 1 (ASGR1) and tyrosine aminotransferase (TAT)] and metabolic enzymes (UDP-glucuronosyltransferase 1A1 and CYP3A4) in hiHep significantly increased after celecoxib treatment. These mRNA expression levels were 7-, 1/3-, 1/2-, and 1/10-fold of the HPHs cultured for 48 hours, respectively. Furthermore, CYP3A4 activity significantly increased. To investigate the mechanism of CYP3A4 mRNA upregulation, we analyzed the phosphorylation of STAT5 after celecoxib treatment and found it to be significantly increased. Moreover, the increase in CYP3A4 mRNA expression was attenuated by cotreatment with STAT5 inhibitor. These results suggest that celecoxib promotes hepatocyte differentiation of hiHep by activating STAT5 and is useful for the generation of functional hiHep.

Cyclic AMP Signaling Promotes the Differentiation of Human Induced Pluripotent Stem Cells into Intestinal Epithelial Cells.

To develop a novel in vitro system for predicting intestinal drug absorption using human induced pluripotent stem (iPS) cell-derived intestinal epithelial cells, the cells need to have sufficient drug-metabolizing enzyme and drug transporter activities. We found that cyclic adenosine monophosphate (cAMP) signaling plays an important role in the differentiation of human iPS cells into intestinal epithelial cells. In this study, we aimed to demonstrate the effects of signaling activation in the intestinal differentiation of human iPS cells and the pharmacokinetic characteristics of human iPS cell-derived intestinal epithelial cells. Human iPS cells were differentiated into intestinal stem cells using activin A and fibroblast growth factor 2. Subsequently, the intestinal stem cells were maturated into intestinal epithelial cells by treatment with 8-bromo-cyclic adenosine monophosphate (8-Br-cAMP) and 3-isobutyl-1-methylxanthine (IBMX), which activate cAMP signaling. The expression levels of intestinal markers and pharmacokinetics-related genes in the differentiated cells were markedly increased by using 8-Br-cAMP and IBMX. In the cells differentiated with the compound we observed cytochrome P450 (CYP) 3A4 inducibility via pregnane X receptor and vitamin D receptor. The metabolic activities of CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, and UDP-glucuronosyltransferase, which are expressed in the human small intestine, were also markedly increased. Furthermore, uptake of glycylsarcosine via peptide transporter 1 was markedly increased. The cells differentiated with the compounds also had drug transporter activities via organic anion transporters and P-glycoprotein. This study is the first to report that the activation of cAMP signaling promotes differentiation of human iPS cell-derived intestinal epithelial cells.

Generation of Intestinal Organoids Suitable for Pharmacokinetic Studies from Human Induced Pluripotent Stem Cells.

Intestinal organoids morphologically resemble intestinal tissues and are expected to be used in both regenerative medicine and drug development studies, including pharmacokinetic studies. However, the pharmacokinetic properties of these organoids remain poorly characterized. In this study, we aimed to generate pharmacokinetically functional intestinal organoids from human induced pluripotent stem (iPS) cells. Human iPS cells were induced to differentiate into the midgut and then seeded on EZSPHERE plates (AGC Techno Glass Inc., Shizuoka, Japan) to generate uniform spheroids, and the floating spheroids were subsequently differentiated into intestinal organoids using small-molecule compounds. Exposure to the small-molecule compounds potently increased the expression of intestinal markers and pharmacokinetic-related genes in the organoids, and the organoids also included various intestinal cells such as enterocytes, intestinal stem cells, goblet cells, enteroendocrine cells, Paneth cells, smooth muscle cells, and fibroblasts. Moreover, microvilli and tight junctions were observed in the organoids. Furthermore, we detected not only the expression of drug transporters but also efflux transport activity through ABCB1/MDR1 and the induction of the drug-metabolizing enzyme CYP3A4 by ligands of nuclear receptors. Our results demonstrated the successful generation of pharmacokinetically functional intestinal organoids from human iPS cells. Thus, these intestinal organoids could be used as a pharmacokinetic evaluation system in drug development studies.

Using human iPS cell-derived enterocytes as novel in vitro model for the evaluation of human intestinal mucosal damage.

OBJECTIVE AND DESIGN: The primary component in gut mucus is mucin 2 (MUC2) secreted by goblet cells. Fluctuations in MUC2 expression are considered a useful indicator for evaluating mucosal damage and protective effect of various agents using animal studies. However, there are few in vitro studies evaluating mucosal damage using MUC2 as the indicator. Hence, we attempted to establish a novel in vitro model with MUC2 as the indicator for evaluating drug-induced mucosal damage and protective effect using enterocytes derived from human iPS cells. METHODS: Compounds were added into enterocytes derived from human iPS cells, and MUC2 mRNA and protein expression levels were evaluated. Further, the effect of compounds on membrane permeability was investigated. RESULTS: Nonsteroidal anti-inflammatory drugs were found to decrease MUC2 mRNA expression in enterocytes, whereas mucosal protective agents increased mRNA levels. Changes in MUC2 protein expression were consistent with those of mRNA. Additionally, our results indicated that indomethacin caused mucosal damage, affecting membrane permeability of the drug. Moreover, we observed protective effect of rebamipide against the indomethacin-induced permeability increase. CONCLUSIONS: The developed model could facilitate evaluating drug-induced mucosal damage and protective effects of various agents and could impact drug development studies regarding pharmacological efficacy and safety.

Enhancement of Warfarin Anticoagulant Reaction in Patients with Repeated Oral Tolvaptan Administration.

The pharmacokinetics and pharmacodynamics of warfarin remained unaffected by tolvaptan during clinical trials. However, tolvaptan prolonged the prothrombin time-international normalized ratio (PT-INR) level of patients with cardiovascular disease taking warfarin. Tolvaptan was prescribed to 576 patients from December 2010 to December 2015. Of these patients, 37 underwent anticoagulant therapy. We investigated PT-INR fluctuation immediately before tolvaptan therapy was initiated. PT-INR remained unchanged in the control group and in groups administered with less than 7.5 mg/d tolvaptan, whereas it was significantly increased (p=0.03) in the group administered with more than 7.5 mg/d tolvaptan. This result indicates the possibility that tolvaptan affects the pharmacodynamics of warfarin in vivo. However, further research is necessary to clarify the mechanism of this phenomenon.

Functional analysis of carboxylesterase in human induced pluripotent stem cell-derived enterocytes.

Human carboxylesterase (CES) is a key esterase involved in the metabolism and biotransformation of drugs. Hydrolysis activity in the human small intestine is predominantly mediated by CES2A1 rather than CES1A. In drug development studies, Caco-2 cells are commonly used as a model to predict drug absorption in the human small intestine. However, the expression patterns of CES2A1 and CES1A in Caco-2 cells differ from those in the human small intestine. There are also species-specific differences in CES expression patterns between human and experimental animals. Furthermore, it is difficult to obtain primary human intestinal epithelial cells. Therefore, there is currently no system that can precisely predict features of drug absorption, such as CES-mediated metabolism, in the human intestine. To develop a novel system to evaluate intestinal pharmacokinetics, we analyzed CES expression and function in human induced pluripotent stem (iPS) cell-derived enterocytes. CES2A1 mRNA and protein levels in human iPS cell-derived enterocytes were comparable to Caco-2 cells, whereas CES1A levels were lower in human iPS cell-derived enterocytes compared with Caco-2 cells. p-nitrophenyl acetate hydrolysis in human iPS cell-derived enterocytes was significantly inhibited by the CES2A1-specific inhibitor telmisartan. Hydrolysis levels of the CES2A1-specific substrate aspirin were similar in human iPS cell-derived enterocytes and Caco-2 cells, whereas hydrolysis of the CES1A-specific substrate monoethylglycylxylidine was observed in Caco-2 cells but not in human iPS cell-derived enterocytes. These findings demonstrated that the expression and activity of CES isozymes in human iPS cell-derived enterocytes are more similar to the human small intestine compared with Caco-2 cells.

Characteristic Analysis of Intestinal Transport in Enterocyte-Like Cells Differentiated from Human Induced Pluripotent Stem Cells.

We previously demonstrated that differentiated enterocytes from human induced pluripotent stem (iPS) cells exhibited drug-metabolizing activities and cytochrome P450 CYP3A4 inducibility. The aim of this study was to apply human iPS cell-derived enterocytes in pharmacokinetic studies by investigating the characteristics of drug transport into enterocyte-like cells. Human iPS cells cultured on feeder cells were differentiated into endodermal cells using activin A. These endodermal-like cells were then differentiated into intestinal stem cells by fibroblast growth factor 2. Finally, epidermal growth factor and small-molecule compounds induced the maturation of the intestinal stem cell-like cells. After differentiation, we performed transepithelial electrical resistance (TEER) measurements, immunofluorescence staining, and transport studies. TEER values increased in a time-dependent manner and reached approximately 100 Ω × cm(2) Efflux transport of Hoechst 33342, a substrate of breast cancer resistance protein (BCRP), was observed and inhibited by the BCRP inhibitor Ko143. The uptake of peptide transporter 1 substrate glycylsarcosine was also confirmed and suppressed when the temperature was lowered to 4°C. Using immunofluorescence staining, villin and Na(+)-K(+) ATPase were expressed. These results suggest that human iPS cell-derived enterocytes had loose tight junctions, polarity, as well as uptake and efflux transport functions. In addition, the rank order of apparent membrane permeability coefficient (Papp) values of these test compounds across the enterocyte-like cell membrane corresponded to the fraction absorbance (Fa) values. Therefore, differentiated enterocytes from human iPS cells may provide a useful comprehensive evaluation model of drug transport and metabolism in the small intestine.

Generation of enterocyte-like cells with pharmacokinetic functions from human induced pluripotent stem cells using small-molecule compounds.

The small intestine plays an important role in all aspects of pharmacokinetics, but there is no system for the comprehensive evaluation of small-intestinal pharmacokinetics, including drug metabolism and absorption. In this study, we aimed to construct an intestinal pharmacokinetics evaluation system and to generate pharmacokinetically functional enterocytes from human induced pluripotent stem cells. Using activin A and fibroblast growth factor 2, we differentiated these stem cells into intestinal stem cell-like cells, and the resulting cells were differentiated into enterocytes in a medium containing epidermal growth factor and small-molecule compounds. The differentiated cells expressed intestinal marker genes and drug transporters. The expression of sucrase-isomaltase, an intestine-specific marker, was markedly increased by small-molecule compounds. The cells exhibited activities of drug-metabolizing enzymes expressed in enterocytes, including CYP1A1/2, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, UGT, and sulfotransferase. Fluorescence-labeled dipeptide uptake into the cells was observed and was inhibited by ibuprofen, an inhibitor of the intestinal oligopeptide transporter solute carrier 15A1/PEPT1. CYP3A4 mRNA expression level was increased by these compounds and induced by the addition of 1α,25-dihydroxyvitamin D3. CYP3A4/5 activity was also induced by 1α,25-dihydroxyvitamin D3 in cells differentiated in the presence of the compounds. All these results show that we have generated enterocyte-like cells that have pharmacokinetic functions, and we have identified small-molecule compounds that are effective for promoting intestinal differentiation and the gain of pharmacokinetic functions. Our enterocyte-like cells would be useful material for developing a novel evaluation system to predict human intestinal pharmacokinetics.

Human small intestinal epithelial cells differentiated from adult intestinal stem cells as a novel system for predicting oral drug absorption in humans.

Adult intestinal stem cells (ISCs) possess both a long-term proliferation ability and differentiation capability into enterocytes. As a novel in vitro system for the evaluation of drug absorption, we characterized a human small intestinal epithelial cell (HIEC) monolayer that differentiated from adult ISCs. Continuous proliferation/differentiation from ISCs consistently conferred the capability of maturation of enterocytes to HIECs over 25 passages. The morphologically matured HIEC monolayer consisted of polarized columnar epithelia with dense microvilli, tight junctions, and desmosomes 8 days after seeding onto culture inserts. Transepithelial electrical resistance across the monolayer was 9-fold lower in HIECs (98.9 Ω × cm(2)) than in Caco-2 cells (900 Ω × cm(2)), which indicated that the looseness of the tight junctions in the HIEC monolayer was similar to that in the human small intestine (approximately 40 Ω × cm(2)). No significant differences were observed in the overall gene expression patterns of the major drug-metabolizing enzymes and transporters between the HIEC and Caco-2 cell monolayers. Furthermore, the functions of P-glycoprotein and breast cancer resistance protein in the HIEC monolayer were confirmed by the vectorial transport of marker substrates and their disappearance in the presence of specific inhibitors. The apparent drug permeability values of paracellularly transported compounds (fluorescein isothiocyanate-dextran 4000, atenolol, and terbutaline) and nucleoside transporter substrates (didanosine, ribavirin, and doxifluridine) in the HIEC monolayer were markedly higher than those of Caco-2 cells, whereas transcellularly transported drugs (pindolol and midazolam) were equally well permeated. In conclusion, the HIEC monolayer can serve as a novel and superior alternative to the conventional Caco-2 cell monolayer for predicting oral absorption in humans.

Air-liquid interface culture and modified culture medium promote the differentiation of human induced pluripotent stem cells into intestinal epithelial cells.

An in vitro system that evaluates pharmacokinetics in the small intestine is crucial for the development of oral drugs. We produced human induced pluripotent stem cell-derived small intestinal epithelial cells (hiSIECs) with high drug metabolizing enzyme and drug transporter activities. However, the gene expression of our hiSIECs partially differed from that of the human small intestine, with low drug metabolizing enzyme activities. Therefore, we used air-liquid interface (ALI) culture and 5-aza-2'-deoxycytidine (5AZA)-free medium to generate hiSIECs (novel hiSIECs). Novel hiSIECs showed enhanced gene expression of drug metabolizing enzymes, such as cytochrome P450 (CYP)3A4, CYP2C9, CYP2C19, and carboxylesterase 2 that are highly expressed in the small intestine. In addition, the expression of genes involved in nutrient absorption-one of the major functions of the small intestine-also increased. The novel hiSIECs expressed ZO-1 and E-cadherin. Moreover, the novel hiSIECs exhibited a barrier function that allowed low lucifer yellow permeation. The novel hiSIECs showed high activities of CYP3A4, CYP2C9, and CYP2C19, which are abundantly expressed in the small intestine. In conclusion, the novel hiSIECs have great potential as an in vitro system to evaluate pharmacokinetics in the small intestine.

Phagocytosis model of calcium oxalate monohydrate crystals generated using human induced pluripotent stem cell-derived macrophages.

Macrophages play a role in nephrolithiasis, offering the possibility of developing macrophage-mediated preventive therapies. To establish a system for screening drugs that could prevent the formation of kidney stones, we aimed to develop a model using human induced pluripotent stem cell (iPSC)-derived macrophages to study phagocytosis of calcium oxalate monohydrate (COM) crystals. Human iPSCs (201B7) were cultured. CD14+ monocytes were recovered using a stepwise process that involved the use of growth factors and cytokines. These cells were then allowed to differentiate into M1 and M2 macrophages. The macrophages were co-cultured with COM crystals and used in the phagocytosis experiments. Live cell imaging and polarized light observation via super-resolution microscopy were used to visualize phagocytosis. Localization of phagocytosed COM crystals was observed using transmission electron microscopy. Intracellular fluorescence intensity was measured using imaging cytometry to quantify phagocytosis. Human iPSCs successfully differentiated into M1 and M2 macrophages. M1 macrophages adhered to the culture plate and moved COM crystals from the periphery to cell center over time, whereas M2 macrophages did not adhere to the culture plate and actively phagocytosed the surrounding COM crystals. Fluorescence assessment over a 24-h period showed that M2 macrophages exhibited higher intracellular fluorescence intensity (5.65-times higher than that of M1 macrophages at 4.5 h) and maintained this advantage for 18 h. This study revealed that human iPSC-derived macrophages have the ability to phagocytose COM crystals, presenting a new approach for studying urinary stone formation and highlighting the potential of iPSC-derived macrophages as a tool to screen nephrolithiasis-related drugs.