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An Essential Role for Liver ERα in Coupling Hepatic Metabolism to the Reproductive Cycle.

Della Torre S, Mitro N, Fontana R, Gomaraschi M, Favari E, Recordati C, Lolli F, Quagliarini F, Meda C, Ohlsson C, Crestani M, Uhlenhaut NH, Calabresi L, Maggi A - Cell Rep (2016)

Bottom Line: We show that this receptor regulates the synthesis of cholesterol transport proteins, enzymes for lipoprotein remodeling, and receptors for cholesterol uptake.Additionally, ERα is indispensable during proestrus for the generation of high-density lipoproteins efficient in eliciting cholesterol efflux from macrophages.We propose that a specific interaction with liver X receptor α (LXRα) mediates the broad effects of ERα on the hepatic lipid metabolism.

View Article: PubMed Central - PubMed

Affiliation: Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy; Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy.

No MeSH data available.


Related in: MedlinePlus

Inhibition of the Transcriptional Activity of LXRα by ERα: In Vitro Studies(A) HeLa cells were co-transfected with LXRα and the reporter LXRE-Luc in the presence or absence of ERα. Where indicated, LXRα agonist T0901317 (T09), E2 plus T09, and ERα antagonist ICI 182,780 (ICI) were added. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. VEH, vehicle. ∗∗∗p < 0.001 versus LXRα/LXRE-Luc+T09; Op < 0.05 and OOOp < 0.001 versus LXRα/LXRE-Luc+E2+T09; #p < 0.05 and ###p < 0.001 versus LXRα/LXRE-Luc+ICI+E2+T09.(B) Effect of ERα on the transcriptional activity of PPARα. The cells were co-transfected with PPARα and the reporter PPRE-Luc in the presence or absence of ERα. Where indicated, the cells were treated with the PPARα agonist WY-14,643 (WY), E2 + WY, and ICI + E2 + WY. The data indicate mean ± SEM, n = 4; the experiment was repeated three times.(C and D) HeLa cells were co-transfected with LXRα and the reporter ABCA1-Luc (C) or SREBP1C-Luc (D) in the presence or absence of ERα. Treatments were done with vehicle, T09, or E2 + T09. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 versus VEH; Op < 0.05 and OOOp < 0.001 versus LXRα/ABCA1-Luc+T09; +p < 0.05 and +++p < 0.001 versus LXRα/ABCA1-Luc+E2+T09.(E) Identification of the co-activators of the LXRα (top) and ERα (bottom) proteins by FRET. SRC-1, PGC-1α, RIP140, CBP, TIF2, nuclear receptor corepressor (NCoR), and TRAP220. The data indicate mean ± SEM, n = 2; the experiment was repeated twice.(F) FRET analysis of the changes in the recruitment of co-activators by LXRα in the presence of increasing amounts of ERα stimulated with DMSO (dark lanes) or 5 nM E2 (red lanes). The data indicate mean ± SEM, n = 2; the experiment was repeated three times.BLI, bioluminescence imaging; RLU, relative light units.
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fig5: Inhibition of the Transcriptional Activity of LXRα by ERα: In Vitro Studies(A) HeLa cells were co-transfected with LXRα and the reporter LXRE-Luc in the presence or absence of ERα. Where indicated, LXRα agonist T0901317 (T09), E2 plus T09, and ERα antagonist ICI 182,780 (ICI) were added. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. VEH, vehicle. ∗∗∗p < 0.001 versus LXRα/LXRE-Luc+T09; Op < 0.05 and OOOp < 0.001 versus LXRα/LXRE-Luc+E2+T09; #p < 0.05 and ###p < 0.001 versus LXRα/LXRE-Luc+ICI+E2+T09.(B) Effect of ERα on the transcriptional activity of PPARα. The cells were co-transfected with PPARα and the reporter PPRE-Luc in the presence or absence of ERα. Where indicated, the cells were treated with the PPARα agonist WY-14,643 (WY), E2 + WY, and ICI + E2 + WY. The data indicate mean ± SEM, n = 4; the experiment was repeated three times.(C and D) HeLa cells were co-transfected with LXRα and the reporter ABCA1-Luc (C) or SREBP1C-Luc (D) in the presence or absence of ERα. Treatments were done with vehicle, T09, or E2 + T09. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 versus VEH; Op < 0.05 and OOOp < 0.001 versus LXRα/ABCA1-Luc+T09; +p < 0.05 and +++p < 0.001 versus LXRα/ABCA1-Luc+E2+T09.(E) Identification of the co-activators of the LXRα (top) and ERα (bottom) proteins by FRET. SRC-1, PGC-1α, RIP140, CBP, TIF2, nuclear receptor corepressor (NCoR), and TRAP220. The data indicate mean ± SEM, n = 2; the experiment was repeated twice.(F) FRET analysis of the changes in the recruitment of co-activators by LXRα in the presence of increasing amounts of ERα stimulated with DMSO (dark lanes) or 5 nM E2 (red lanes). The data indicate mean ± SEM, n = 2; the experiment was repeated three times.BLI, bioluminescence imaging; RLU, relative light units.

Mentions: The existence of a functional interaction between ERα and LXRα was further investigated in co-transfection studies. Figure 5A shows that the LXRα-dependent activity of the LXRE-Luc promoter was augmented 13.6-fold in the presence of the LXRα-specific agonist T0901317 (T09). Co-transfection with increasing concentrations of ERα in the presence of 10 nM E2 substantially diminished LXRα transcriptional efficiency (from 9.3- to 5.0-fold at the highest ERα concentration). However, when the ERα antagonist ICI 182,780 was added, ERα inhibition was maintained. This highlighted the possibility of a ligand-independent effect of ERα, which was further demonstrated in transfection experiments performed in the absence of E2 (data not shown). Remarkably, this effect was specific to LXRα, because the transcriptional activity of PPARα that was stimulated by its agonist WY-14,643 was not altered by the presence of ERα with E2 or E2 plus ICI 182,780 (Figure 5B). Next, we asked whether the unliganded ERα was able to interfere with LXRα activity on the ABCA1 and SREBP-1c promoters. Figures 5C and 5D show that ERα interfered with LXRα transcriptional activity on the ABCA1, but not of the SREBP-1c promoter. This was consistent with prior observation (Figure 4D) that the transcription of SREBP-1c in liver was not modulated by the estrous cycle or influenced by the absence of liver ERα.


An Essential Role for Liver ERα in Coupling Hepatic Metabolism to the Reproductive Cycle.

Della Torre S, Mitro N, Fontana R, Gomaraschi M, Favari E, Recordati C, Lolli F, Quagliarini F, Meda C, Ohlsson C, Crestani M, Uhlenhaut NH, Calabresi L, Maggi A - Cell Rep (2016)

Inhibition of the Transcriptional Activity of LXRα by ERα: In Vitro Studies(A) HeLa cells were co-transfected with LXRα and the reporter LXRE-Luc in the presence or absence of ERα. Where indicated, LXRα agonist T0901317 (T09), E2 plus T09, and ERα antagonist ICI 182,780 (ICI) were added. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. VEH, vehicle. ∗∗∗p < 0.001 versus LXRα/LXRE-Luc+T09; Op < 0.05 and OOOp < 0.001 versus LXRα/LXRE-Luc+E2+T09; #p < 0.05 and ###p < 0.001 versus LXRα/LXRE-Luc+ICI+E2+T09.(B) Effect of ERα on the transcriptional activity of PPARα. The cells were co-transfected with PPARα and the reporter PPRE-Luc in the presence or absence of ERα. Where indicated, the cells were treated with the PPARα agonist WY-14,643 (WY), E2 + WY, and ICI + E2 + WY. The data indicate mean ± SEM, n = 4; the experiment was repeated three times.(C and D) HeLa cells were co-transfected with LXRα and the reporter ABCA1-Luc (C) or SREBP1C-Luc (D) in the presence or absence of ERα. Treatments were done with vehicle, T09, or E2 + T09. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 versus VEH; Op < 0.05 and OOOp < 0.001 versus LXRα/ABCA1-Luc+T09; +p < 0.05 and +++p < 0.001 versus LXRα/ABCA1-Luc+E2+T09.(E) Identification of the co-activators of the LXRα (top) and ERα (bottom) proteins by FRET. SRC-1, PGC-1α, RIP140, CBP, TIF2, nuclear receptor corepressor (NCoR), and TRAP220. The data indicate mean ± SEM, n = 2; the experiment was repeated twice.(F) FRET analysis of the changes in the recruitment of co-activators by LXRα in the presence of increasing amounts of ERα stimulated with DMSO (dark lanes) or 5 nM E2 (red lanes). The data indicate mean ± SEM, n = 2; the experiment was repeated three times.BLI, bioluminescence imaging; RLU, relative light units.
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fig5: Inhibition of the Transcriptional Activity of LXRα by ERα: In Vitro Studies(A) HeLa cells were co-transfected with LXRα and the reporter LXRE-Luc in the presence or absence of ERα. Where indicated, LXRα agonist T0901317 (T09), E2 plus T09, and ERα antagonist ICI 182,780 (ICI) were added. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. VEH, vehicle. ∗∗∗p < 0.001 versus LXRα/LXRE-Luc+T09; Op < 0.05 and OOOp < 0.001 versus LXRα/LXRE-Luc+E2+T09; #p < 0.05 and ###p < 0.001 versus LXRα/LXRE-Luc+ICI+E2+T09.(B) Effect of ERα on the transcriptional activity of PPARα. The cells were co-transfected with PPARα and the reporter PPRE-Luc in the presence or absence of ERα. Where indicated, the cells were treated with the PPARα agonist WY-14,643 (WY), E2 + WY, and ICI + E2 + WY. The data indicate mean ± SEM, n = 4; the experiment was repeated three times.(C and D) HeLa cells were co-transfected with LXRα and the reporter ABCA1-Luc (C) or SREBP1C-Luc (D) in the presence or absence of ERα. Treatments were done with vehicle, T09, or E2 + T09. The data indicate mean ± SEM, n = 4; each experiment was repeated three times. ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001 versus VEH; Op < 0.05 and OOOp < 0.001 versus LXRα/ABCA1-Luc+T09; +p < 0.05 and +++p < 0.001 versus LXRα/ABCA1-Luc+E2+T09.(E) Identification of the co-activators of the LXRα (top) and ERα (bottom) proteins by FRET. SRC-1, PGC-1α, RIP140, CBP, TIF2, nuclear receptor corepressor (NCoR), and TRAP220. The data indicate mean ± SEM, n = 2; the experiment was repeated twice.(F) FRET analysis of the changes in the recruitment of co-activators by LXRα in the presence of increasing amounts of ERα stimulated with DMSO (dark lanes) or 5 nM E2 (red lanes). The data indicate mean ± SEM, n = 2; the experiment was repeated three times.BLI, bioluminescence imaging; RLU, relative light units.
Mentions: The existence of a functional interaction between ERα and LXRα was further investigated in co-transfection studies. Figure 5A shows that the LXRα-dependent activity of the LXRE-Luc promoter was augmented 13.6-fold in the presence of the LXRα-specific agonist T0901317 (T09). Co-transfection with increasing concentrations of ERα in the presence of 10 nM E2 substantially diminished LXRα transcriptional efficiency (from 9.3- to 5.0-fold at the highest ERα concentration). However, when the ERα antagonist ICI 182,780 was added, ERα inhibition was maintained. This highlighted the possibility of a ligand-independent effect of ERα, which was further demonstrated in transfection experiments performed in the absence of E2 (data not shown). Remarkably, this effect was specific to LXRα, because the transcriptional activity of PPARα that was stimulated by its agonist WY-14,643 was not altered by the presence of ERα with E2 or E2 plus ICI 182,780 (Figure 5B). Next, we asked whether the unliganded ERα was able to interfere with LXRα activity on the ABCA1 and SREBP-1c promoters. Figures 5C and 5D show that ERα interfered with LXRα transcriptional activity on the ABCA1, but not of the SREBP-1c promoter. This was consistent with prior observation (Figure 4D) that the transcription of SREBP-1c in liver was not modulated by the estrous cycle or influenced by the absence of liver ERα.

Bottom Line: We show that this receptor regulates the synthesis of cholesterol transport proteins, enzymes for lipoprotein remodeling, and receptors for cholesterol uptake.Additionally, ERα is indispensable during proestrus for the generation of high-density lipoproteins efficient in eliciting cholesterol efflux from macrophages.We propose that a specific interaction with liver X receptor α (LXRα) mediates the broad effects of ERα on the hepatic lipid metabolism.

View Article: PubMed Central - PubMed

Affiliation: Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy; Department of Pharmacological and Biomolecular Sciences, University of Milan, 20133 Milan, Italy.

No MeSH data available.


Related in: MedlinePlus