NPC1L1 gene expression is down‐regulated by stearic acid in CCL‐241 cells

Abstract

We previously reported in hamsters that dietary stearic acid significantly reduced cholesterol absorption and increased biliary cholesterol excretion (J Nutr 130:1232, 2000). Niemann-Pick C1 like 1 (NPC1L1) protein has recently been described and found to be critical for the intestinal absorption of dietary and biliary cholesterol. In the present study, we tested the hypothesis that stearic acid, compared to other fatty acids commonly found in the food supply, down-regulates NPC1L1 gene expression in the human intestinal cell line CCL-241. Cells were incubated 24 h with 100 μM stearic, palmitic, oleic, or linoleic acid complexed to BSA. Total RNA was extracted from ~1 x 106 cells using trizol, reverse transcribed to cDNA, and mRNA quantified using real time PCR. CCL-241 cells incubated with stearic acid exhibited 40–50% reduction in NPC1L1 mRNA abundance compared to cells incubated with palmitic, oleic, or linoleic acid. The data indicate that the expression of NPC1L1 is responsive to fatty acids and that stearic acid may limit intestinal cholesterol absorption by down-regulating NPC1L1 gene expression. [Supported by NSF-EPSCoR grant EPS-0346476 and the Nebraska Agricultural Research Division.]