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Deficiency of Capicua disrupts bile acid homeostasis.

Kim E, Park S, Choi N, Lee J, Yoe J, Kim S, Jung HY, Kim KT, Kang H, Fryer JD, Zoghbi HY, Hwang D, Lee Y - Sci Rep (2015)

Bottom Line: We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L(-/-) liver.Moreover, induction of tumor necrosis factor alpha (Tnfα) expression and decrease in the levels of FOXA2, C/EBPβ, and RXRα were found in Cic-L(-/-) liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L(-/-) mice.Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.

ABSTRACT
Capicua (CIC) has been implicated in pathogenesis of spinocerebellar ataxia type 1 and cancer in mammals; however, the in vivo physiological functions of CIC remain largely unknown. Here we show that Cic hypomorphic (Cic-L(-/-)) mice have impaired bile acid (BA) homeostasis associated with induction of proinflammatory cytokines. We discovered that several drug metabolism and BA transporter genes were down-regulated in Cic-L(-/-) liver, and that BA was increased in the liver and serum whereas bile was decreased within the gallbladder of Cic-L(-/-) mice. We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L(-/-) liver. Consistent with this finding, levels of hepatic transcriptional regulators, such as hepatic nuclear factor 1 alpha (HNF1α), CCAAT/enhancer-binding protein beta (C/EBPβ), forkhead box protein A2 (FOXA2), and retinoid X receptor alpha (RXRα), were markedly decreased in Cic-L(-/-) mice. Moreover, induction of tumor necrosis factor alpha (Tnfα) expression and decrease in the levels of FOXA2, C/EBPβ, and RXRα were found in Cic-L(-/-) liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L(-/-) mice. Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders.

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Down-regulation of drug metabolism genes in Cic-L-/- liver.(a) Heat map showing up- and down-regulated genes in Cic-L-/- mice (KO) at P18, compared with WT. The numbers in x-axis denote four replicates used in WT and KO. Red and green colors represent increase and decrease in expression levels of the genes, respectively, from the mean expression levels of the eight replicates. Color bar, gradient of log2-difference of the intensities from the median intensities. (b) KEGG pathways significantly represented by the up- and down-regulated genes in Cic-L-/- liver. The significance was represented by -log10(P) where P is the enrichment P-value obtained from the DAVID software. The number of the up- or down-regulated genes involved in each pathway is shown. (c) qRT-PCR analysis for levels of nineteen phase I and phase II drug metabolism genes in livers from 18 day-old WT and Cic-L-/- mice (n = 4~5 per each genotype). *P<0.05, **P<0.01, and ***P<0.001. All error bars show s.e.m.
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f2: Down-regulation of drug metabolism genes in Cic-L-/- liver.(a) Heat map showing up- and down-regulated genes in Cic-L-/- mice (KO) at P18, compared with WT. The numbers in x-axis denote four replicates used in WT and KO. Red and green colors represent increase and decrease in expression levels of the genes, respectively, from the mean expression levels of the eight replicates. Color bar, gradient of log2-difference of the intensities from the median intensities. (b) KEGG pathways significantly represented by the up- and down-regulated genes in Cic-L-/- liver. The significance was represented by -log10(P) where P is the enrichment P-value obtained from the DAVID software. The number of the up- or down-regulated genes involved in each pathway is shown. (c) qRT-PCR analysis for levels of nineteen phase I and phase II drug metabolism genes in livers from 18 day-old WT and Cic-L-/- mice (n = 4~5 per each genotype). *P<0.05, **P<0.01, and ***P<0.001. All error bars show s.e.m.

Mentions: Hepatic expression of CIC proteins and significant alterations in levels of several serum metabolites in Cic-L-/- mice led us to investigate roles of CIC in liver given its role in a wide variety of metabolic processes. To examine hepatic gene expression changes caused by deficiency of CIC, we carried out microarray analysis using liver total RNA from WT and Cic-L-/- mice at P18 (four mice per each genotype). A total of 718 differentially expressed genes (DEGs; P < 0.05) between WT and Cic-L-/- mice (405 up-regulated and 313 down-regulated in Cic-L-/- liver) were identified using an integrative statistical method (Fig. 2a and Table S1). To examine cellular pathways represented by the DEGs, we performed KEGG pathway enrichment analysis for the DEGs using DAVID software17. The analysis revealed that the down-regulated genes most significantly represented those involved in drug metabolism (also known as xenobiotic metabolism) (Fig. 2b). Drug metabolism involves a set of enzymatic processes and transporters that modify and remove toxic chemicals from cells in three phases. Phase I is conducted by enzymes mediating oxidation, reduction, or hydroxylation, such as cytochrome P450 enzymes (CYPs), flavin-containing monooxygenases (FMOs), alcohol dehydrogenases (ADHs), and aldehyde dehydrogenases (ALDHs). In phase II, phase I products are conjugated with charged species, such as glutathione, sulfate, and glucuronic acid mediated by glutathione-S-transferases (GSTs), sulfotransferases (SULTs), and UDP-glucuronosyltransferases (UGTs). In phase III, the conjugates can be excreted from cells by a variety of membrane transporters including multidrug resistance protein (MRP) family. Proteins involved in drug metabolism act not only on the pharmaceutical drugs or xenobiotics, but also on endogenous metabolites including BA to maintain their homeostasis. Using qRT-PCR, we confirmed the down-regulation of several phase I and phase II drug metabolism genes in Cic-L-/- liver. Sixteen (84%) out of the 19 tested genes were significantly down-regulated in Cic-L-/- livers obtained from an independent cohort of animals (Fig. 2c). Taken together, these data suggest that drug metabolism is likely the hepatocellular pathway most significantly affected by CIC deficiency.


Deficiency of Capicua disrupts bile acid homeostasis.

Kim E, Park S, Choi N, Lee J, Yoe J, Kim S, Jung HY, Kim KT, Kang H, Fryer JD, Zoghbi HY, Hwang D, Lee Y - Sci Rep (2015)

Down-regulation of drug metabolism genes in Cic-L-/- liver.(a) Heat map showing up- and down-regulated genes in Cic-L-/- mice (KO) at P18, compared with WT. The numbers in x-axis denote four replicates used in WT and KO. Red and green colors represent increase and decrease in expression levels of the genes, respectively, from the mean expression levels of the eight replicates. Color bar, gradient of log2-difference of the intensities from the median intensities. (b) KEGG pathways significantly represented by the up- and down-regulated genes in Cic-L-/- liver. The significance was represented by -log10(P) where P is the enrichment P-value obtained from the DAVID software. The number of the up- or down-regulated genes involved in each pathway is shown. (c) qRT-PCR analysis for levels of nineteen phase I and phase II drug metabolism genes in livers from 18 day-old WT and Cic-L-/- mice (n = 4~5 per each genotype). *P<0.05, **P<0.01, and ***P<0.001. All error bars show s.e.m.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4317698&req=5

f2: Down-regulation of drug metabolism genes in Cic-L-/- liver.(a) Heat map showing up- and down-regulated genes in Cic-L-/- mice (KO) at P18, compared with WT. The numbers in x-axis denote four replicates used in WT and KO. Red and green colors represent increase and decrease in expression levels of the genes, respectively, from the mean expression levels of the eight replicates. Color bar, gradient of log2-difference of the intensities from the median intensities. (b) KEGG pathways significantly represented by the up- and down-regulated genes in Cic-L-/- liver. The significance was represented by -log10(P) where P is the enrichment P-value obtained from the DAVID software. The number of the up- or down-regulated genes involved in each pathway is shown. (c) qRT-PCR analysis for levels of nineteen phase I and phase II drug metabolism genes in livers from 18 day-old WT and Cic-L-/- mice (n = 4~5 per each genotype). *P<0.05, **P<0.01, and ***P<0.001. All error bars show s.e.m.
Mentions: Hepatic expression of CIC proteins and significant alterations in levels of several serum metabolites in Cic-L-/- mice led us to investigate roles of CIC in liver given its role in a wide variety of metabolic processes. To examine hepatic gene expression changes caused by deficiency of CIC, we carried out microarray analysis using liver total RNA from WT and Cic-L-/- mice at P18 (four mice per each genotype). A total of 718 differentially expressed genes (DEGs; P < 0.05) between WT and Cic-L-/- mice (405 up-regulated and 313 down-regulated in Cic-L-/- liver) were identified using an integrative statistical method (Fig. 2a and Table S1). To examine cellular pathways represented by the DEGs, we performed KEGG pathway enrichment analysis for the DEGs using DAVID software17. The analysis revealed that the down-regulated genes most significantly represented those involved in drug metabolism (also known as xenobiotic metabolism) (Fig. 2b). Drug metabolism involves a set of enzymatic processes and transporters that modify and remove toxic chemicals from cells in three phases. Phase I is conducted by enzymes mediating oxidation, reduction, or hydroxylation, such as cytochrome P450 enzymes (CYPs), flavin-containing monooxygenases (FMOs), alcohol dehydrogenases (ADHs), and aldehyde dehydrogenases (ALDHs). In phase II, phase I products are conjugated with charged species, such as glutathione, sulfate, and glucuronic acid mediated by glutathione-S-transferases (GSTs), sulfotransferases (SULTs), and UDP-glucuronosyltransferases (UGTs). In phase III, the conjugates can be excreted from cells by a variety of membrane transporters including multidrug resistance protein (MRP) family. Proteins involved in drug metabolism act not only on the pharmaceutical drugs or xenobiotics, but also on endogenous metabolites including BA to maintain their homeostasis. Using qRT-PCR, we confirmed the down-regulation of several phase I and phase II drug metabolism genes in Cic-L-/- liver. Sixteen (84%) out of the 19 tested genes were significantly down-regulated in Cic-L-/- livers obtained from an independent cohort of animals (Fig. 2c). Taken together, these data suggest that drug metabolism is likely the hepatocellular pathway most significantly affected by CIC deficiency.

Bottom Line: We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L(-/-) liver.Moreover, induction of tumor necrosis factor alpha (Tnfα) expression and decrease in the levels of FOXA2, C/EBPβ, and RXRα were found in Cic-L(-/-) liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L(-/-) mice.Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.

ABSTRACT
Capicua (CIC) has been implicated in pathogenesis of spinocerebellar ataxia type 1 and cancer in mammals; however, the in vivo physiological functions of CIC remain largely unknown. Here we show that Cic hypomorphic (Cic-L(-/-)) mice have impaired bile acid (BA) homeostasis associated with induction of proinflammatory cytokines. We discovered that several drug metabolism and BA transporter genes were down-regulated in Cic-L(-/-) liver, and that BA was increased in the liver and serum whereas bile was decreased within the gallbladder of Cic-L(-/-) mice. We also found that levels of proinflammatory cytokine genes were up-regulated in Cic-L(-/-) liver. Consistent with this finding, levels of hepatic transcriptional regulators, such as hepatic nuclear factor 1 alpha (HNF1α), CCAAT/enhancer-binding protein beta (C/EBPβ), forkhead box protein A2 (FOXA2), and retinoid X receptor alpha (RXRα), were markedly decreased in Cic-L(-/-) mice. Moreover, induction of tumor necrosis factor alpha (Tnfα) expression and decrease in the levels of FOXA2, C/EBPβ, and RXRα were found in Cic-L(-/-) liver before BA was accumulated, suggesting that inflammation might be the cause for the cholestasis in Cic-L(-/-) mice. Our findings indicate that CIC is a critical regulator of BA homeostasis, and that its dysfunction might be associated with chronic liver disease and metabolic disorders.

Show MeSH
Related in: MedlinePlus