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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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Related in: MedlinePlus

Decrease in protein levels of hepatic transcription factors and induction of Tnfα expression in Cic-L-/- liver at P10.(a) Measurement of hepatic BA concentration in 10 day-old WT and Cic-L-/- mice (n = 5 per each genotype). All error bars show s.e.m. (b) qRT-PCR analysis for levels of Shp mRNA in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). Error bar shows s.e.m. (c) Western blot image showing the decrease in FOXA2, C/EBPβ, and RXRα protein levels in Cic-L-/- liver at P10. The right panel is a bar graph for quantitative analysis on levels of FOXA2, C/EBPβ, and RXRα based on Western blot image. *P<0.05 and #P = 0.0587. All error bars show s.e.m. (d) qRT-PCR analysis for levels of eighteen drug metabolism genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and ***P<0.001. All error bars show s.e.m. (e) qRT-PCR analysis for levels of membrane transporter genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and **P<0.01. All error bars show s.e.m. (f) qRT-PCR analysis for levels of Il-1β, Il-6, and Tnfα using liver total RNAs prepared from 10 day-old WT and Cic-L-/- mice (n = 4 per each genotype). *P<0.05. All error bars show s.e.m.
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f5: Decrease in protein levels of hepatic transcription factors and induction of Tnfα expression in Cic-L-/- liver at P10.(a) Measurement of hepatic BA concentration in 10 day-old WT and Cic-L-/- mice (n = 5 per each genotype). All error bars show s.e.m. (b) qRT-PCR analysis for levels of Shp mRNA in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). Error bar shows s.e.m. (c) Western blot image showing the decrease in FOXA2, C/EBPβ, and RXRα protein levels in Cic-L-/- liver at P10. The right panel is a bar graph for quantitative analysis on levels of FOXA2, C/EBPβ, and RXRα based on Western blot image. *P<0.05 and #P = 0.0587. All error bars show s.e.m. (d) qRT-PCR analysis for levels of eighteen drug metabolism genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and ***P<0.001. All error bars show s.e.m. (e) qRT-PCR analysis for levels of membrane transporter genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and **P<0.01. All error bars show s.e.m. (f) qRT-PCR analysis for levels of Il-1β, Il-6, and Tnfα using liver total RNAs prepared from 10 day-old WT and Cic-L-/- mice (n = 4 per each genotype). *P<0.05. All error bars show s.e.m.

Mentions: Because inflammation can cause hepatic cholestasis and vice versa, it was not clear whether the impaired BA homeostasis is the cause or an effect of the reduced protein levels of FOXA2, HNF1α, C/EBPβ, and RXRα, and up-regulation of proinflammatory cytokine genes in Cic-L-/- liver. To address this, we assessed levels of FOXA2, HNF1α, C/EBPβ, and RXRα at P10, when levels of hepatic BA and Shp mRNA are comparable between WT and Cic-L-/- mice (Figs. 5a and 5b). We found that protein levels of FOXA2, C/EBPβ, and RXRα were still decreased in Cic-L-/- liver compared with WT (Fig. 5c), although the fold decrease in FOXA2 and C/EBPβ protein levels was less dramatic at P10 than at P18 (Figs. 4a and 5c). These data suggest that hepatic cholestasis is not the primary cause for the reduction in levels of FOXA2, C/EBPβ, and RXRα in Cic-L-/- mice, but that it could be facilitated as hepatic cholestasis develops. HNF1α proteins were not detectable in livers at P10 under our experimental conditions. Among eighteen drug metabolism genes with decreased levels in Cic-L-/- liver at P18 (Fig. 2c), seven were significantly down-regulated and half of them showed a trend toward down-regulation in livers from 10 day-old Cic-L-/- mice (Fig. 5d), suggesting that decreased levels of a subset of hepatic transcription factors are probably associated with the down-regulation of drug metabolism genes in Cic-L-/- mice. We also checked hepatic levels of the membrane transporter genes in Cic-L-/- mice at P10. Among five genes, only Oatp2 and Mdr2 levels were significantly down-regulated in livers of Cic-L-/- mice at P10 (Fig. 5e), suggesting that decreased levels of Ntcp, Bsep, and Oatp-b might critically contribute to the disruption in BA homeostasis in Cic-L-/- mice at P18. Finally, we examined the expression of proinflammatory cytokine genes in liver of Cic-L-/- mice at P10. We found that Tnfα levels were significantly increased in Cic-L-/- mice compared with WT (Fig. 5f), suggesting that inflammatory response was already induced in Cic-L-/- liver at P10, but amplified during cholestasis, based on more dramatic and significant fold increase in the levels of proinflammatory cytokine genes in Cic-L-/- liver at P18 than at P10 (Figs. 4c and 5f). Taken together, these data suggest that CIC deficiency induces proinflammatory signaling cascades in liver, thereby perturbing BA homeostasis.


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)

Decrease in protein levels of hepatic transcription factors and induction of Tnfα expression in Cic-L-/- liver at P10.(a) Measurement of hepatic BA concentration in 10 day-old WT and Cic-L-/- mice (n = 5 per each genotype). All error bars show s.e.m. (b) qRT-PCR analysis for levels of Shp mRNA in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). Error bar shows s.e.m. (c) Western blot image showing the decrease in FOXA2, C/EBPβ, and RXRα protein levels in Cic-L-/- liver at P10. The right panel is a bar graph for quantitative analysis on levels of FOXA2, C/EBPβ, and RXRα based on Western blot image. *P<0.05 and #P = 0.0587. All error bars show s.e.m. (d) qRT-PCR analysis for levels of eighteen drug metabolism genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and ***P<0.001. All error bars show s.e.m. (e) qRT-PCR analysis for levels of membrane transporter genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and **P<0.01. All error bars show s.e.m. (f) qRT-PCR analysis for levels of Il-1β, Il-6, and Tnfα using liver total RNAs prepared from 10 day-old WT and Cic-L-/- mice (n = 4 per each genotype). *P<0.05. All error bars show s.e.m.
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f5: Decrease in protein levels of hepatic transcription factors and induction of Tnfα expression in Cic-L-/- liver at P10.(a) Measurement of hepatic BA concentration in 10 day-old WT and Cic-L-/- mice (n = 5 per each genotype). All error bars show s.e.m. (b) qRT-PCR analysis for levels of Shp mRNA in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). Error bar shows s.e.m. (c) Western blot image showing the decrease in FOXA2, C/EBPβ, and RXRα protein levels in Cic-L-/- liver at P10. The right panel is a bar graph for quantitative analysis on levels of FOXA2, C/EBPβ, and RXRα based on Western blot image. *P<0.05 and #P = 0.0587. All error bars show s.e.m. (d) qRT-PCR analysis for levels of eighteen drug metabolism genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and ***P<0.001. All error bars show s.e.m. (e) qRT-PCR analysis for levels of membrane transporter genes in livers from 10 day-old WT and Cic-L-/- mice (n = 3 per each genotype). *P<0.05 and **P<0.01. All error bars show s.e.m. (f) qRT-PCR analysis for levels of Il-1β, Il-6, and Tnfα using liver total RNAs prepared from 10 day-old WT and Cic-L-/- mice (n = 4 per each genotype). *P<0.05. All error bars show s.e.m.
Mentions: Because inflammation can cause hepatic cholestasis and vice versa, it was not clear whether the impaired BA homeostasis is the cause or an effect of the reduced protein levels of FOXA2, HNF1α, C/EBPβ, and RXRα, and up-regulation of proinflammatory cytokine genes in Cic-L-/- liver. To address this, we assessed levels of FOXA2, HNF1α, C/EBPβ, and RXRα at P10, when levels of hepatic BA and Shp mRNA are comparable between WT and Cic-L-/- mice (Figs. 5a and 5b). We found that protein levels of FOXA2, C/EBPβ, and RXRα were still decreased in Cic-L-/- liver compared with WT (Fig. 5c), although the fold decrease in FOXA2 and C/EBPβ protein levels was less dramatic at P10 than at P18 (Figs. 4a and 5c). These data suggest that hepatic cholestasis is not the primary cause for the reduction in levels of FOXA2, C/EBPβ, and RXRα in Cic-L-/- mice, but that it could be facilitated as hepatic cholestasis develops. HNF1α proteins were not detectable in livers at P10 under our experimental conditions. Among eighteen drug metabolism genes with decreased levels in Cic-L-/- liver at P18 (Fig. 2c), seven were significantly down-regulated and half of them showed a trend toward down-regulation in livers from 10 day-old Cic-L-/- mice (Fig. 5d), suggesting that decreased levels of a subset of hepatic transcription factors are probably associated with the down-regulation of drug metabolism genes in Cic-L-/- mice. We also checked hepatic levels of the membrane transporter genes in Cic-L-/- mice at P10. Among five genes, only Oatp2 and Mdr2 levels were significantly down-regulated in livers of Cic-L-/- mice at P10 (Fig. 5e), suggesting that decreased levels of Ntcp, Bsep, and Oatp-b might critically contribute to the disruption in BA homeostasis in Cic-L-/- mice at P18. Finally, we examined the expression of proinflammatory cytokine genes in liver of Cic-L-/- mice at P10. We found that Tnfα levels were significantly increased in Cic-L-/- mice compared with WT (Fig. 5f), suggesting that inflammatory response was already induced in Cic-L-/- liver at P10, but amplified during cholestasis, based on more dramatic and significant fold increase in the levels of proinflammatory cytokine genes in Cic-L-/- liver at P18 than at P10 (Figs. 4c and 5f). Taken together, these data suggest that CIC deficiency induces proinflammatory signaling cascades in liver, thereby perturbing BA homeostasis.

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