Regulation of hepatic bile acid transporters Ntcp and Bsep expression

Dissecting modes of action of non-genotoxic carcinogens in primary mouse hepatocytes

Under REACH, the European Community Regulation on chemicals, the testing strategy for carcinogenicity is based on in vitro and in vivo genotoxicity assays. Given that non-genotoxic carcinogens are negative for genotoxicity and chronic bioassays are no longer regularly performed, this class of carcinogens will go undetected. Therefore, test systems detecting non-genotoxic carcinogens, or even better their modes of action, are required. Here, we investigated whether gene expression profiling in primary hepatocytes can be used to distinguish different modes of action of non-genotoxic carcinogens. For this, primary mouse hepatocytes were exposed to 16 non-genotoxic carcinogens with diverse modes of action. Upon profiling, pathway analysis was performed to obtain insight into the biological relevance of the observed changes in gene expression. Subsequently, both a supervised and an unsupervised comparison approach were applied to recognize the modes of action at the transcriptomic level. These analyses resulted in the detection of three of eight compound classes, that is, peroxisome proliferators, metalloids and skin tumor promotors. In conclusion, gene expression profiles in primary hepatocytes, at least in rodent hepatocytes, appear to be useful to detect some, certainly not all, modes of action of non-genotoxic carcinogens.

The traditional ayurvedic medicine, Eugenia jambolana (Jamun fruit), decreases liver inflammation, injury and fibrosis during cholestasis

BACKGROUND

Cholestasis is a common disease of the liver. Chronic cholestasis eventually leads to hepatic cirrhosis and fibrosis, and rodent chronic cholestasis models are used to study aspects of fibrosis and cirrhosis. Cholestasis-induced liver injury and fibrosis are associated with increased oxidative stress and inflammation. Few pharmacological therapies exist for treatment of cholestasis or cirrhosis, but it is known that humans with better nutritional intake are less likely to develop certain types of cirrhosis. Eugenia jambolana (Jamun) is a tropical berry fruit rich in antioxidant anthocyanin compounds.

AIM

As anthocyanins decrease cellular lipid peroxidation and oxidative stress, it was hypothesized that Jamun fruit extract (JFE) administration could protect against cholestatic liver injury and inflammation in mice.

METHOD

Starting 24 h after sham or bile-duct ligation (BDL) surgery, male C57Bl/6 mice were administered vehicle or JFE (100 mg/kg, po) for 10 days.

RESULTS

Mice that underwent BDL had elevated serum ALT levels, which were reduced to 60% by JFE treatment. Likewise, BDL caused hepatic inflammation, macrophage infiltration, fibrosis and necrosis, all of which were largely improved by JFE. Interestingly, hepatoprotection was observed in JFE-treated BDL mice, despite suppressed transporter expression and increased hepatic bile acid concentrations.

CONCLUSION

Jamun fruit phytochemicals decreased hepatic inflammation and oxidative stress, and protected against hepatocellular injury in mice. Jamun warrants further investigation as a potential antioxidant/anti-inflammatory therapy not only to treat cholestasis but also other liver diseases with an inflammatory component.

RNA-Seq reveals different mRNA abundance of transporters and their alternative transcript isoforms during liver development

During development, the maturation of liver transporters is essential for chemical elimination in newborns and children. One cannot compare the real abundance of transcripts by conventional messenger RNA (mRNA) profiling methods; in comparison, RNA-Seq provides a "true quantification" of transcript counts and an unbiased detection of novel transcripts. The purpose of this study was to compare the mRNA abundance of liver transporters and seek their novel transcripts during liver development. Livers from male C57BL/6J mice were collected at 12 ages from prenatal to adulthood. The transcriptome was determined by RNA-Seq, with transcript abundance estimated by Cufflinks. Among 498 known transporters, the ontogeny of 62 known critical xenobiotic transporters was examined in detail. The cumulative mRNAs of the uptake transporters increased more than the efflux transporters in livers after birth. A heatmap revealed three ontogenic patterns of these transporters, namely perinatal (reaching maximal expression before birth), adolescent (about 20 days), and adult enriched (about 60 days of age). Before birth, equilibrative nucleoside transporter 1 was the transporter with highest expression in liver (29%), followed by breast cancer resistance protein (Bcrp) (26%). Within 1 day after birth, the mRNAs of these two transporters decreased markedly, and Ntcp became the transporter with highest expression (52%). In adult liver, the transporters with highest expression were organic cation transporter 1 and Ntcp (23% and 22%, respectively). Three isoforms of Bcrp with alternate leading exons were identified (E1a, E1b, and E1c), with E1b being the major isoform. In conclusion, this study reveals the mRNA abundance of transporters in liver and demonstrates that the expression of liver transporters is both age and isoform specific.

Gender-divergent profile of bile acid homeostasis during aging of mice

Aging is a physiological process with a progressive decline of adaptation and functional capacity of the body. Bile acids (BAs) have been recognized as signaling molecules regulating the homeostasis of glucose, lipid, and energy. The current study characterizes the age-related changes of individual BA concentrations by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in serum and liver of male and female C57BL/6 mice from 3 to 27 months of age. Total BA concentrations in serum increased 340% from 3 to 27 months in female mice, whereas they remained relatively constant with age in male mice. During aging, male and female mice shared the following changes: (1) BA concentrations in liver remained relatively constant; (2) the proportions of beta-muricholic acid (βMCA) increased and deoxycholic acid (DCA) decreased between 3 and 27 months in serum and liver; and (3) total BAs in serum and liver became more hydrophilic between 3 and 27 months. In female mice, (1) the mRNAs of hepatic BA uptake transporters, the Na⁺/taurocholate cotransporting polypeptide (Ntcp) and the organic anion transporting polypeptide 1b2 (Oatp1b2), decreased after 12 months, and similar trends were observed for their proteins; (2) the mRNA of the rate-limiting enzyme for BA synthesis, cholesterol 7α-hydroxylase (Cyp7a1), increased from 3 to 9 months and remained high thereafter. However, in male mice, Ntcp, Oatp1b2, and Cyp7a1 mRNAs remained relatively constant with age. In summary, the current study shows gender-divergent profiles of BA concentrations and composition in serum and liver of mice during aging, which is likely due to the gender-divergent expression of BA transporters Ntcp and Oatp1b2 as well as the synthetic enzyme Cyp7a1.

Loss of organic anion transporting polypeptide 1a1 increases deoxycholic acid absorption in mice by increasing intestinal permeability

Deoxycholic acid (DCA) is a known hepatotoxicant, a tissue tumor promoter, and has been implicated in colorectal cancer. Male mice are more susceptible to DCA toxicity than female mice. Organic anion transporting polypeptide 1a1 (Oatp1a1), which is known to transport bile acids (BAs) in vitro, is predominantly expressed in livers of male mice. In addition, the concentrations of DCA and its taurine conjugate (TDCA) are increased in serum of Oatp1a1-null mice. To investigate whether Oatp1a1 contributes to the gender difference in DCA toxicity in mice, wild-type (WT) and Oatp1a1-null mice were fed a 0.3% DCA diet for 7 days. After feeding DCA, Oatp1a1-null mice had 30-fold higher concentrations of DCA in both serum and livers than WT mice. Feeding DCA caused more hepatotoxcity in Oatp1a1-null mice than WT mice. After feeding DCA, Oatp1a1-null mice expressed higher BA efflux-transporters (bile salt-export pump, organic solute transporter (Ost)α/β, and multidrug resistance-associated protein [Mrp]2) and lower BA-synthetic enzymes (cytochrome P450 [Cyp]7a1, 8b1, 27a1, and 7b1) in livers than WT mice. Intravenous administration of DCA and TDCA showed that lack of Oatp1a1 does not decrease the plasma elimination of DCA or TDCA. After feeding DCA, the concentrations of DCA in ileum and colon tissues are higher in Oatp1a1-null than in WT mice. In addition, Oatp1a1-null mice have enhanced intestinal permeability. Taken together, the current data suggest that Oatp1a1 does not mediate the hepatic uptake of DCA or TDCA, but lack of Oatp1a1 increases intestinal permeability and thus enhances the absorption of DCA in mice.

Molecular control of systemic bile acid homeostasis by the liver glucocorticoid receptor

Systemic bile acid (BA) homeostasis is a critical determinant of dietary fat digestion, enterohepatic function, and postprandial thermogenesis. However, major checkpoints for the dynamics and the molecular regulation of BA homeostasis remain unknown. Here we show that hypothalamic-pituitary-adrenal (HPA) axis impairment in humans and liver-specific deficiency of the glucocorticoid receptor (GR) in mice disrupts the normal changes in systemic BA distribution during the fasted-to-fed transition. Fasted mice with hepatocyte-specific GR knockdown had smaller gallbladder BA content and were more susceptible to developing cholesterol gallstones when fed a cholesterol-rich diet. Hepatic GR deficiency impaired liver BA uptake/transport via lower expression of the major hepatocyte basolateral BA transporter, Na(+)-taurocholate transport protein (Ntcp/Slc10a1), which affected dietary fat absorption and brown adipose tissue activation. Our results demonstrate a role of the HPA axis in the endocrine regulation of BA homeostasis through the liver GR control of enterohepatic BA recycling.

Diurnal variations of mouse plasma and hepatic bile acid concentrations as well as expression of biosynthetic enzymes and transporters

Background

Diurnal fluctuation of bile acid (BA) concentrations in the enterohepatic system of mammals has been known for a long time. Recently, BAs have been recognized as signaling molecules beyond their well-established roles in dietary lipid absorption and cholesterol homeostasis.

Methods and Results

The current study depicted diurnal variations of individual BAs detected by ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) in serum and livers collected from C57BL/6 mice fed a regular chow or a chow containing cholestyramine (resin). Circadian rhythms of mRNA of vital BA-related nuclear receptors, enzymes, and transporters in livers and ilea were determined in control- and resin-fed mice, as well as in farnesoid X receptor (FXR) null mice. The circadian profiles of BAs showed enhanced bacterial dehydroxylation during the fasting phase and efficient hepatic reconjugation of BAs in the fed phase. The resin removed more than 90% of BAs with β-hydroxy groups, such as muricholic acids and ursodeoxycholic acid, from serum and livers, but did not exert as significant influence on CA and CDCA in both compartments. Both resin-fed and FXR-null mouse models indicate that BAs regulate their own biosynthesis through the FXR-regulated ileal fibroblast growth factor 15. BA flux also influences the daily mRNA levels of multiple BA transporters.

Conclusion

BA concentration and composition exhibit circadian variations in mouse liver and serum, which influences the circadian rhythms of BA metabolizing genes in liver and ileum. The diurnal variations of BAs appear to serve as a signal that coordinates daily nutrient metabolism in mammals.

Alterations in hepatic mRNA expression of phase II enzymes and xenobiotic transporters after targeted disruption of hepatocyte nuclear factor 4 alpha

Hepatocyte nuclear factor 4 alpha (HNF4a) is a liver-enriched master regulator of liver function. HNF4a is important in regulating hepatic expression of certain cytochrome P450s. The purpose of this study was to use mice lacking HNF4a expression in liver (HNF4a-HNull) to elucidate the role of HNF4a in regulating hepatic expression of phase II enzymes and transporters in mice. Compared with male wild-type mice, HNF4a-HNull male mouse livers had (1) markedly lower messenger RNAs (mRNAs) encoding the uptake transporters sodium taurocholate cotransporting polypeptide, organic anion transporting polypeptide (Oatp) 1a1, Oatp2b1, organic anion transporter 2, sodium phosphate cotransporter type 1, sulfate anion transporter 1, sodium-dependent vitamin C transporter 1, the phase II enzymes Uridine 5'-diphospho (UDP)-glucuronosyltransferase (Ugt) 2a3, Ugt2b1, Ugt3a1, Ugt3a2, sulfotransferase (Sult) 1a1, Sult1b1, Sult5a1, the efflux transporters multidrug resistance-associated protein (Mrp) 6, and multidrug and toxin extrusion 1; (2) moderately lower mRNAs encoding Oatp1b2, organic cation transporter (Oct) 1, Ugt1a5, Ugt1a9, glutathione S-transferase (Gst) m4, Gstm6, and breast cancer resistance protein; but (3) higher mRNAs encoding Oatp1a4, Octn2, Ugt1a1, Sult1e1, Sult2a2, Gsta4, Gstm1-m3, multidrug resistance protein (Mdr) 1a, Mrp3, and Mrp4. Hepatic signaling of nuclear factor E2-related factor 2 and pregnane X receptor appear to be activated in HNF4a-HNull mice. In conclusion, HNF4a deficiency markedly alters hepatic mRNA expression of a large number of phase II enzymes and transporters, probably because of the loss of HNF4a, which is a transactivator and a determinant of gender-specific expression and/or adaptive activation of signaling pathways important in hepatic regulation of these phase II enzymes and transporters.

Xenobiotic, bile acid, and cholesterol transporters: function and regulation

Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting beta polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) alpha and beta] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory factors that influence transporter expression and function, including transcriptional activation and post-translational modifications as well as subcellular trafficking. Sex differences, ontogeny, and pharmacological and toxicological regulation of transporters are also addressed. Transporters are important transmembrane proteins that mediate the cellular entry and exit of a wide range of substrates throughout the body and thereby play important roles in human physiology, pharmacology, pathology, and toxicology.

Study of the transport of thyroid hormone by transporters of the SLC10 family

Transport of (sulfated) iodothyronines across the plasma membrane is required for their intracellular metabolism. Rat Na(+)/taurocholate cotransporting polypeptide (Ntcp; Slc10a1) has been identified as an important transporter protein. We demonstrate that among the 7 members of the solute carrier family SLC10, only human SLC10A1 mediates sodium-dependent transport of the iodothyronine T4 and iodothyronine sulfates T3S and T4S. In contrast to SLC10A2-7, cells co-expressing SLC10A1 and the deiodinase D1 demonstrate a dramatic increase in T3S and T4S metabolism. The SLC10A1 substrates taurocholate, DHEAS and E3S inhibit T3S and T4S transport. Furthermore, co-transfection of SLC10A1 with CRYM, a well-known intracellular iodothyronine-binding protein, results in an enhanced intracellular accumulation of T3S and T4S, indicating that CRYM binds iodothyronine sulfates. The present findings indicate that the liver-specific transporter SLC10A1 transports (sulfated) iodothyronines, thereby increasing their intracellular availability. Therefore, SLC10A1 may fulfill a critical step in providing liver D1 with iodothyronine sulfates for rapid degradation.

Nrf2 the rescue: effects of the antioxidative/electrophilic response on the liver

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor that positively regulates the basal and inducible expression of a large battery of cytoprotective genes. These gene products include proteins that catalyze reduction reactions (NAD(P)H:quinone oxidoreductase 1, Nqo1), conjugation reactions (glutathione-S-transferases, Gsts and UDP-glucuronosyltransferases, Ugts), as well as the efflux of potentially toxic xenobiotics and xenobiotic conjugates (multidrug resistance-associated proteins, Mrps). The significance of Nrf2 in the liver has been established, as livers of Nrf2-null mice are more susceptible to various oxidative/electrophilic stress-induced pathologies than wild-type mice. In contrast, both pharmacological and genetic models of hepatic Nrf2 activation are protective against oxidative/electrophilic stress. Furthermore, because certain Nrf2-target genes in the liver could affect the distribution, metabolism, and excretion of xenobiotics, the effects of Nrf2 on the kinetics of drugs and other xenobiotics should also be considered, with a special emphasis on metabolism and excretion. Therefore, this review highlights the research that has contributed to the understanding of the importance of Nrf2 in toxicodynamics and toxicokinetics, especially that which pertains to the liver.

Role of hepatic transporters in prevention of bile acid toxicity after partial hepatectomy in mice

The enterohepatic recirculation of bile acids (BAs) is important in several physiological processes. Although there has been considerable research on liver regeneration after two-thirds partial hepatectomy (PHx), little is known about how the liver protects itself against BA toxicity during regeneration. In this study, various BAs in plasma and liver, the composition of micelle-forming bile constituents, as well as gene expression of the main hepatobiliary transporters were quantified in sham-operated and PHx mice 24 and 48 h after surgery. PHx did not influence the hepatic concentrations of taurine-conjugated BAs (T-BA) but increased the concentration of glycine-conjugated (G-BA) and unconjugated BAs. Total BA excretion (microg x min(-1) x g liver wt(-1)) increased 2.4-fold and was accompanied by a 55% increase in bile flow after PHx. The plasma concentrations of T-BAs (402-fold), G-BAs (17-fold), and unconjugated BAs (500-fold) increased. The mRNA and protein levels of the BA uptake transporter Ntcp were unchanged after PHx, whereas the canalicular Bsep protein increased twofold at 48 h. The basolateral efflux transporter Mrp3 was induced at the mRNA (2.6-fold) and protein (3.1-fold) levels after PHx, which may contribute to elevated plasma BA and bilirubin levels. Biliary phospholipid excretion was nearly doubled in PHx mice, most likely owing to increased mRNA expression of the phospholipid transporter, Mdr2. In conclusion, the remnant liver after PHx excretes 2.5-fold more BAs and three times more phospholipids per gram liver than the sham-operated mouse liver. Upregulation of phospholipid transport may be important in protecting the biliary tract from BA toxicity during PHx.

Nuclear receptors as therapeutic targets in cholestatic liver diseases

Cholestasis results in intrahepatic accumulation of cytotoxic bile acids, which cause liver damage ultimately leading to biliary fibrosis and cirrhosis. Cholestatic liver injury is counteracted by a variety of adaptive hepatoprotective mechanisms including alterations in bile acid transport, synthesis and detoxification. The underlying molecular mechanisms are mediated mainly at a transcriptional level via a complex network involving nuclear receptors including the farnesoid X receptor, pregnane X receptor, vitamin D receptor and constitutive androstane receptor, which target overlapping, although not identical, sets of genes. Because the intrinsic adaptive response to bile acids cannot fully prevent liver injury in cholestasis, therapeutic targeting of these receptors via specific and potent agonists may further enhance the hepatic defence against toxic bile acids. Activation of these receptors results in repression of bile acid synthesis, induction of phases I and II bile acid hydroxylation and conjugation and stimulation of alternative bile acid export while limiting hepatocellular bile acid import. Furthermore, the use of nuclear receptor ligands may not only influence bile acid transport and metabolism but may also directly target hepatic fibrogenesis and inflammation. Many drugs already used to treat cholestasis and its complications such as pruritus (e.g. ursodeoxycholic acid, rifampicin, fibrates) may act via activation of nuclear receptors. More specific and potent nuclear receptor ligands are currently being developed. This article will review the current knowledge on nuclear receptors and their potential role in the treatment of cholestatic liver diseases.

Hematopoietically expressed homeobox is a target gene of farnesoid X receptor in chenodeoxycholic acid-induced liver hypertrophy

Farnesoid X receptor (FXR/Fxr) is a bile acid-regulated nuclear receptor that promotes hepatic bile acid metabolism, detoxification, and liver regeneration. However, the adaptive pathways under conditions of bile acid stress are not fully elucidated. We found that wild-type but not Fxr knockout mice on diets enriched with chenodeoxycholic acid (CDCA) increase their liver/body weight ratios by 50% due to hepatocellular hypertrophy. Microarray analysis identified Hex (Hematopoietically expressed homeobox), a central transcription factor in vertebrate embryogenesis and liver development, as a novel CDCA- and Fxr-regulated gene. HEX/Hex was also regulated by FXR/Fxr and CDCA in primary mouse hepatocytes and human HepG2 cells. Comparative genomic analysis identified a conserved inverted repeat-1-like DNA sequence within a 300 base pair enhancer element of intron-1 in the human and mouse HEX/Hex gene. A combination of chromatin immunoprecipitation, electromobility shift assay, and transcriptional reporter assays demonstrated that FXR/Fxr binds to this element and mediates HEX/Hex transcriptional activation.

CONCLUSION

HEX/Hex is a novel bile acid-induced FXR/Fxr target gene during adaptation of hepatocytes to chronic bile acid exposure.

Bile acid transporters in health and disease

In recent years the discovery of a number of major transporter proteins expressed in the liver and intestine specifically involved in bile acid transport has led to improved understanding of bile acid homeostasis and the enterohepatic circulation. Sodium (Na(+))-dependent bile acid uptake from portal blood into the liver is mediated primarily by the Na(+) taurocholate co-transporting polypeptide (NTCP), while secretion across the canalicular membrane into the bile is carried out by the bile salt export pump (BSEP). In the ileum, absorption of bile acids from the lumen into epithelial cells is mediated by the apical Na(+) bile salt transporter (ASBT), whereas exit into portal blood across the basolateral membrane is mediated by the organic solute transporter alpha/beta (OSTalpha/beta) heterodimer. Regulation of transporter gene expression and function occurs at several different levels: in the nucleus, members of the nuclear receptor superfamily, regulated by bile acids and other ligands are primarily involved in controlling gene expression, while cell signalling events directly affect transporter function, and subcellular localization. Polymorphisms, dysfunction, and impaired adaptive responses of several of the bile acid transporters, e.g. BSEP and ASBT, results in liver and intestinal disease. Bile acid transporters are now understood to play central roles in driving bile flow, as well as adaptation to various pathological conditions, with complex regulation of activity and function in the nucleus, cytoplasm, and membrane.

Resistance of young rat hepatic mitochondria to bile acid-induced permeability transition: potential role of alpha-tocopherol

Retention of bile acids within the liver is a primary factor in the pathogenesis of cholestatic liver disorders, which are more common in human infants. The objective of this study was to evaluate developmental changes in mitochondrial factors involved in bile acid-induced hepatocyte injury. Hepatic mitochondria from adult rats (aged 9 wk) underwent a mitochondrial permeability transition (MPT) and release of cytochrome c upon exposure to glycochenodeoxycholic acid. In contrast, mitochondria from young rats (age 6-36 d) were resistant to MPT induction and cytochrome c release. Neither mitochondrial levels of MPT-associated proteins (voltage-dependent anion channel, cyclophilin D, or adenine nucleotide translocase), Bcl-2 family proteins, nor antioxidant enzymes explained this resistance. Mitochondria from young rats contained 2- to 3-fold higher alpha-tocopherol (alpha-TH). In vivo alpha-TH enrichment of adult hepatic mitochondria increased their MPT resistance. Tetra-linoleoyl cardiolipin (TL-CL), the primary molecular species of CL, was reduced in mitochondria of the young rat; however, enrichment with CL and TL-CL only modestly increased their MPT susceptibility. In conclusion, we observed an unexpected resistance in young rats to bile acid induction of mitochondrial cell death pathways, which may be related to developmental differences in membrane composition.

Critical role of PPAR-alpha in perfluorooctanoic acid- and perfluorodecanoic acid-induced downregulation of Oatp uptake transporters in mouse livers

Perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) have been detected globally in wildlife and humans. Data from a gene array indicate that PFOA decreases organic anion transporting polypeptides (Oatps) in liver. Na(+)-taurocholate cotransporting polypeptide (Ntcp) and Oatp1a1, 1a4, and 1b2 are major transporters responsible for uptake of bile acids (BAs) and other organic compounds into liver. The purpose of the present study was to determine the effects of two perfluorinated fatty acids, PFOA and PFDA, on mRNA and protein expression of hepatic uptake transporters Oatps and Ntcp, and to determine the underlying regulatory mechanisms by using peroxisome proliferator-activated receptor alpha (PPAR-alpha), constitutive androstane receptor, pregnane-X receptor, NF-E2-related factor 2, and farnesoid X receptor-null mouse models. After 2 days following a single i.p. administration, PFOA did not alter serum BA concentrations, but PFDA increased serum BA concentrations 300%. Furthermore, PFOA decreased mRNA and protein expression of Oatp1a1, 1a4, and 1b2, but not Ntcp in mouse liver. In contrast, PFDA decreased mRNA and protein expression of all four transporters, and decreased the mRNA expression in a dose-dependent manner, with the decrease of Oatp1a4 occurring at lower doses than the other three transporters. Multiple mechanisms are likely involved in the down-regulation of mouse Oatps and Ntcp by PFDA. By using the various transcription factor-null mice, PPAR-alpha was shown to play a central role in the down-regulation of Oatp1a1, 1a4, 1b2, and Ntcp by PFDA. The current studies provide important insight into understanding the mechanisms by which PFDA regulate the expression of hepatic uptake transporters. In conclusion, PFOA and PFDA decrease mouse liver uptake transporters primarily via activation of PPAR-alpha.