Effects of Trichostatin A on drug uptake transporters in primary rat hepatocyte cultures.
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ABSTRACT:
SUBMITTER: Ramboer E
PROVIDER: S-EPMC4669911 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The administration of inorganic Cd and Hg in vivo has been shown to result in markedly different metal concentrations in rat liver. Primary cultures of rat hepatocytes were utilized to gain insight into the dispositional differences between these chemically similar metals. Hepatocyte monolayer cultures were exposed to several concentrations of Cd or Hg (3, 10 and 30mum) in serum-containing medium for 30min. The cells were then washed and incubated in fresh medium for the remainder of the experiment. Hepatocytes exposed to Cd accumulated significantly more metal than hepatocytes exposed to equimolar concentrations of Hg. In cells exposed to 3mum-Cd there was an initial loss of Cd from the hepatocytes when placed in fresh medium, followed by a gradual re-uptake of metal, concomitant with increased binding to metallothionein. In hepatocytes exposed to 3 and 10mum-Cd, 87 and 77% of the intracellular Cd was bound to metallothionein within 24h. Loss of Hg from hepatocytes pulsed with 30mum-Hg was also observed upon the addition of fresh medium and continued for the duration of the experiment. No time-dependent increase in Hg binding to metallothionein was observed. A maximum of about 10% of the intracellular Hg was found associated with metallothionein in hepatocytes exposed to 30mum-Hg. Studies utilizing [(35)S]cysteine incorporation indicated significant increases in the amount of metallothionein synthesized in hepatocytes exposed to 3 and 10mum-Cd (300% of control value) and 30mum-Hg (150% of control value) 24h after metal pulsing. Time-course studies revealed a 6-12h lag in metallothionein synthesis, followed by a significant elevation in [(35)S]cysteine incorporation into metallothionein between 12 and 24h. These studies suggest that (a) isolated hepatocytes differentiate between Cd and Hg and preferentially accumulate the former, and (b) Cd strongly stimulates the induction of, and preferentially binds to, metallothionein, whereas Hg induces weakly, and does not preferentially bind to, metallothionein.
| S-EPMC1153985 | biostudies-other
Project description:The jejunum is the segment of the small intestine responsible for several metabolism and biotransformation functions. In this report, we have cultured rat jejunum explants in vitro and integrated them with hepatocyte cultures. We have also investigated the changes in jejunum function at different locations since spatial variations in intestinal functions have been reported previously. We divided the length of the rat jejunum into three distinct regions of approximately 9 cm each. We defined the regions as proximal (adjacent to the duodenum), medial, and distal (adjacent to the ileum). Spatiotemporal variations in functions were observed between these regions within the jejunum. Alkaline phosphatase activity (a marker of enterocyte function), decreased twofold between the proximal and distal regions at 4 hr. Lysozyme activity (a marker of Paneth cell function) increased from the proximal to the distal jejunum by 40% at 24 hr. Mucin-covered areas, a marker of goblet cell function, increased by twofold between the proximal and distal segments of the jejunum at 24 hr. When hepatocytes were integrated with proximal jejunum explants, statistically higher urea (~2.4-fold) and mucin (57%) production were observed in the jejunum explants. The integrated intestine-liver cultures can be used as a platform for future investigations.
| S-EPMC6971435 | biostudies-literature
Project description:Hepatitis C virus (HCV) remains a major public health problem, affecting approximately 130 million people worldwide. HCV infection can lead to cirrhosis, hepatocellular carcinoma, and end-stage liver disease, as well as extrahepatic complications such as cryoglobulinemia and lymphoma. Preventative and therapeutic options are severely limited; there is no HCV vaccine available, and nonspecific, IFN-based treatments are frequently ineffective. Development of targeted antivirals has been hampered by the lack of robust HCV cell culture systems that reliably predict human responses. Here, we show the entire HCV life cycle recapitulated in micropatterned cocultures (MPCCs) of primary human hepatocytes and supportive stroma in a multiwell format. MPCCs form polarized cell layers expressing all known HCV entry factors and sustain viral replication for several weeks. When coupled with highly sensitive fluorescence- and luminescence-based reporter systems, MPCCs have potential as a high-throughput platform for simultaneous assessment of in vitro efficacy and toxicity profiles of anti-HCV therapeutics.
| S-EPMC2840339 | biostudies-literature
Project description:Primary human hepatocyte (PHH) cultures have become indispensable to mitigate the risk of adverse drug reactions in human patients. In contrast to dedifferentiating monocultures, coculture with nonparenchymal cells maintains PHH functions for 2-4 weeks. However, because the functional lifespan of PHHs in vivo is 200-400 days, it is desirable to further prolong PHH functions in vitro toward modeling chronic drug exposure and disease progression. Fasting has benefits on the longevity of organisms and the health of tissues such as the liver. We hypothesized that a culturing protocol that mimics dynamic fasting/starvation could activate starvation pathways and prolong PHH functional lifetime. To mimic starvation, serum and hormones were intermittently removed from the culture medium of micropatterned cocultures (MPCCs) containing PHHs organized onto collagen domains and surrounded by 3T3-J2 murine fibroblasts. A weekly 2-day starvation optimally prolonged PHH functional lifetime for 6+ weeks in MPCCs versus a decline after 3 weeks in nonstarved controls. The 2-day starvation also enhanced the functions of PHH monocultures for 2 weeks, suggesting direct effects on PHHs. In MPCCs, starvation activated 5' adenosine monophosphate-activated protein kinase (AMPK) and restricted fibroblast overgrowth onto PHH islands, thereby maintaining hepatic polarity. The effects of starvation on MPCCs were partially recapitulated by activating AMPK using metformin or growth arresting fibroblasts via mitomycin-C. Lastly, starved MPCCs demonstrated lower false positives for drug toxicity tests and higher drug-induced cytochrome-P450 activities versus nonstarved controls even after 5 weeks. In conclusion, intermittent serum/hormone starvation extends PHH functional lifetime toward enabling clinically relevant drug screening.
| S-EPMC7098377 | biostudies-literature
Project description:The Kupffer-cell products interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) have been shown to stimulate hepatic lipogenesis in vivo. Studies were performed to define the direct effects of these cytokines on lipogenesis in primary-culture rat hepatocytes. Hepatocytes were cultured in the presence of IL-6 or TNF-alpha for periods of 24-72 h. IL-6 increased hepatocyte protein content per microgram of DNA. IL-6 also caused a dose- and time-dependent induction of hepatocyte capacity for incorporation of [2-14C]pyruvate into fatty acids (56% increase by 12.5 ng/ml IL-6 after 72 h of cytokine exposure). This increase in cellular lipogenic capacity was confirmed by using 3H2O incorporation into fatty acids as tracer. TNF-alpha did not increase hepatocyte lipogenesis. In contrast with studies in vivo, neither IL-6 nor TNF-alpha had any acute (2 h of exposure) effects on rates of lipogenesis. Both IL-6 and TNF-alpha are known to increase macrophage prostaglandin synthesis acutely. The prostaglandin E agonist misoprostol free acid (0.1 microM) acutely increased hepatocyte lipogenic rates by 14%. Thus, IL-6 can directly induce hepatocyte lipogenic capacity, and E-series prostaglandins can antagonize the acute inhibition of lipogenesis by glucagon. The observations provide further evidence for the role of Kupffer-cell products in the regulation of hepatocyte metabolism.
| S-EPMC1137161 | biostudies-other
Project description:Remdesivir has been approved for treatment of COVID-19 and shortens the time to recovery in hospitalized patients. Drug transporters removing remdesivir from the circulation may reduce efficacy of treatment by lowering its plasma levels. Information on the interaction of remdesivir with drug transporters is limited. We therefore assessed remdesivir as substrate and inhibitor of the clinically relevant hepatic drug uptake transporters organic anion transporting poly-peptide (OATP)-1B1 (SLCO1B1), its common genetic variants OATP1B1*1b, OATP1B1*5, OATP1B1*15, as well as OATP1B3 (SLCO1B3), OATP2B1 (SLCO2B1) and organic cation transporter (OCT)-1 (SLC22A1). Previously established transporter-overexpressing cells were used to measure (i) cellular remdesivir uptake and (ii) cellular uptake of transporter probe substrates in the presence of remdesivir. There was a high remdesivir uptake into vector-transfected control cells. Moderate, but statistically significant higher uptake was detected only for OATP1B1-, OATP1B1*1b and OATP1B1*15-expressing cells when compared with control cells at 5 µM. Remdesivir inhibited all investigated transporters at 10 µM and above. In conclusion, the low uptake rates suggest that OATP1B1 and its genetic variants, OATP1B3, OATP2B1 and OCT1 are not relevant for hepatocellular uptake of remdesivir in humans. Due to the rapid clearance of remdesivir, no clinically relevant transporter-mediated drug-drug interactions are expected.
| S-EPMC7999182 | biostudies-literature
Project description:Synthetic substrates that mimic the properties of extracellular matrix proteins hold significant promise for use in systems designed for tissue engineering applications. In this report, we designed a synthetic polymeric substrate that is intended to mimic chemical, mechanical, and topological characteristics of collagen. We found that elastomeric poly(ester amide) substrates modified with replica-molded nanotopographic features enhanced initial attachment, spreading, and adhesion of primary rat hepatocytes. Further, hepatocytes cultured on nanotopographic substrates also demonstrated reduced albumin secretion and urea synthesis, which is indicative of strongly adherent hepatocytes. These results suggest that these engineered substrates can function as synthetic collagen analogs for in vitro cell culture.
| S-EPMC2789736 | biostudies-literature
Project description:In the body, nanoparticles can be systemically distributed and then may affect secondary target organs, such as the central nervous system (CNS). Putative adverse effects on the CNS are rarely investigated to date. Here, we used a mixed primary cell model consisting mainly of neurons and astrocytes and a minor proportion of oligodendrocytes to analyze the effects of well-characterized 20 and 40 nm silver nanoparticles (SNP). Similar gold nanoparticles served as control and proved inert for all endpoints tested. SNP induced a strong size-dependent cytotoxicity. Additionally, in the low concentration range (up to 10 ?g/ml of SNP), the further differentiated cultures were more sensitive to SNP treatment. For detailed studies, we used low/medium dose concentrations (up to 20 ?g/ml) and found strong oxidative stress responses. Reactive oxygen species (ROS) were detected along with the formation of protein carbonyls and the induction of heme oxygenase-1. We observed an acute calcium response, which clearly preceded oxidative stress responses. ROS formation was reduced by antioxidants, whereas the calcium response could not be alleviated by antioxidants. Finally, we looked into the responses of neurons and astrocytes separately. Astrocytes were much more vulnerable to SNP treatment compared with neurons. Consistently, SNP were mainly taken up by astrocytes and not by neurons. Immunofluorescence studies of mixed cell cultures indicated stronger effects on astrocyte morphology. Altogether, we can demonstrate strong effects of SNP associated with calcium dysregulation and ROS formation in primary neural cells, which were detectable already at moderate dosages.
| S-EPMC3307608 | biostudies-literature
Project description:ObjectiveCholine deficiency, one main trigger for nonalcoholic fatty liver disease (NAFLD), is closely related to lipid metabolism disorder. Previous study in a choline-deficient model has largely focused on gene expression rather than gene structure, especially sparse are studies regarding to alternative splicing (AS). In modern life science research, primary hepatocytes culture technology facilitates such studies, which can accurately imitate liver activity in vitro and show unique superiority. Whereas limitations to traditional hepatocytes culture technology exist in terms of efficiency and operability. This study pursued an optimization culture method for duck primary hepatocytes to explore AS in choline-deficient model.MethodsWe performed an optimization culture method for duck primary hepatocytes with multi-step digestion procedure from Pekin duck embryos. Subsequently a NAFLD model was constructed with choline-free medium. RNA-seq and further analysis by rMATS were performed to identify AS events alterations in choline-deficency duck primary hepatocytes.ResultsThe results showed E13 (embryonic day 13) to E15 is suitable to obtain hepatocytes, and the viability reached over 95% by trypan blue exclusion assay. Primary hepatocyte retained their biological function as well identified by Periodic Acid-Schiff staining method and Glucose-6-phosphate dehydrogenase activity assay, respectively. Meanwhile, genes of alb and afp and specific protein of albumin were detected to verify cultured hepatocytes. Immunofluorescence was used to evaluate purity of hepatocytes, presenting up to 90%. On this base, choline-deficient model was constructed and displayed significantly increase of intracellular triglyceride and cholesterol as reported previously. Intriguingly, our data suggested that AS events in choline-deficient model were implicated in pivotal biological processes as an aberrant transcriptional regulator, of which 16 genes were involved in lipid metabolism and highly enriched in glycerophospholipid metabolism.ConclusionAn effective and rapid protocol for obtaining duck primary hepatocytes was established, by which our findings manifested choline deficiency could induce the accumulation of lipid and result in aberrant AS events in hepatocytes, providing a novel insight into various AS in the metabolism role of choline.
| S-EPMC9659469 | biostudies-literature
Project description:Sandwich-cultured rat hepatocytes are used in drug discovery for pharmacological and toxicological assessment of drug candidates, yet their utility as a functional model for drug transporters has not been fully characterized. To evaluate the system as an in vitro model for drug transport, expression changes of hepatic transporters relative to whole liver and freshly isolated hepatocytes (day 0) were examined by real-time quantitative reverse transcription-polymerase chain reaction for 4 consecutive days of culture. No significant differences in transporter expression levels were observed between freshly isolated hepatocytes and whole liver. Two distinct mRNA profiles were detected over time showing 1) a more than 5-fold decline in levels of uptake transporters such as Na(+)-taurocholate cotransporting polypeptide (Ntcp), organic anion transporter (Oat) 2, organic anion-transporting polypeptide (Oatp) 1a1, Oatp1a4, and Oatp1b2 and 2) a greater than 5-fold increase of efflux transporters P-glycoprotein (P-gp), breast cancer resistance protein (Bcrp), and multidrug resistance-related proteins (Mrp) 1, 2, 3, and 4. In addition, protein levels and functional activities for selected transporters were also determined. Protein levels for Mrp2, Bcrp, P-gp, Ntcp, and Oatp1a4 corresponded to changes in mRNA. Functional activities of Oatps and Oct1 exhibited a 3- and 4-fold decrease on day 2 and day 4, respectively, relative to that on day 0, whereas a more than 10-fold reduction in Oat2 activity was observed. These results indicate that the cell culture conditions used herein did not provide an optimal environment for expression of all hepatic transporters. Significant time-dependent alterations in basal gene expression patterns of transporters were detected compared with those in liver or freshly isolated hepatocytes. Further work and new strategies are required to improve the validity of this model as an in vitro tool for in vivo drug transport or biliary clearance prediction.
| S-EPMC3226373 | biostudies-literature