Biochemical and Biophysical Research Communications
Niemann–Pick C1 like 1 gene expression is down-regulated by LXR activators in the intestine
Section snippets
Materials and methods
Caco-2/TC7 cell culture. Cell culture reagents were obtained from Invitrogen and microporous PET membrane inserts (23.1 mm, 3 μm pore size) from Becton Dickinson. Caco-2/TC7 cells (kindly provided by Dr. M. Rousset INSERM U505) were routinely grown in plastic flasks (TPP, ATGC) under a humidified atmosphere containing 10% CO2, at 37 °C, in Dulbecco’s modified essential medium containing 25 mM glucose and glutamax, supplemented with penicillin/streptomycin (100 IU/ml and 100 g/ml, respectively), 1%
PPARα ligands do not regulate NPC1L1 gene expression
Treatment with PPARα ligands has been shown to decrease intestinal cholesterol absorption [16]. To test whether PPARα is implicated in NPC1L1 regulation, polarized Caco-2/TC7 cells were treated with different specific PPARα agonists and hNPC1L1 mRNA expression level was determined. Fig. 1A shows that none of the PPARα agonists tested was able to regulate hNPC1L1 gene expression. However, in the same experiment, hPDK4 was highly up-regulated by all the PPARα ligands tested (Fig. 1B). These
Discussion
NPC1L1 has been shown to play a central role in intestinal cholesterol absorption. Given the role of PPARα and LXRα in cholesterol homeostasis, we tested the possibility of a regulation of NPC1L1 gene expression by these nuclear receptors. In this report, we demonstrate that NPC1L1 gene expression is repressed by LXR but not by PPARα agonists both in mice in vivo and in a human enterocyte cell line in vitro.
Previously, it has been reported that LXRα agonists inhibit intestinal cholesterol
Acknowledgments
This work was supported by grants from the Fondation Leducq and the Groupe Lillois de Recherche en Pathologie Vasculaire - Laboratoires Servier (to C.D.). We thank Bruno Derudas for his technical assistance and K. Bertrand (Genfit SA, France) and P. Brown (Glaxo Smith Kline) for providing the T0901317 and GW3965 compounds and the GW7647 compound, respectively.
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