The transcription factor HNF-4α: a key factor of the intestinal uptake of fatty acids in mouse

Frochot V, Alqub M, Cattin A, Carriere V, Houllier A, Baraille F, Barbot L, Saint-Just S, Ribeiro A, Lacasa M, Cardot P, Chambaz J, Rousset M, Lacorte J. The transcription factor HNF-4 alpha : a key factor of the intestinal uptake of fatty acids in mouse. Am J Physiol Gastrointest Liver Physiol 302: G1253-G1263, 2012. First published March 29, 2012; doi:10.1152/ajpgi.00329.2011.-With an excessive postprandial accumulation of intestine-derived, triglyceride-rich lipoproteins being a risk factor of cardiovascular diseases, it is essential to characterize the mechanisms controlling the intestinal absorption of dietary lipids. Our aim was to investigate the role of the transcription factor hepatocyte nuclear factor (HNF)-4 alpha in this process. We used transgenic mice with a specific and inducible intestinal knockout of Hnf-4 alpha gene. One hour after a lipid bolus, in the presence of the lipase inhibitor tyloxapol, lower amounts of triglycerides were found in both plasma and intestinal epithelium of the intestine-specific Hnf-4 alpha knockout (Hnf-4 alpha(int Delta)) mice compared with the Hnf-4 alpha(loxP/loxP) control mice. These discrepancies were due to a net decrease of the intestinal uptake of fatty acid in Hnf-4 alpha(int Delta) mice compared with Hnf-4 alpha(loxP/loxP) mice, as assessed by the amount of radioactivity that was recovered in intestine and plasma after gavage with labeled triolein or oleic acid, or in intestinal epithelial cells isolated from jejunum after a supply of labeled oleic acid-containing micelles. This decreased fatty acid uptake was associated with significant lower levels of the fatty acid transport protein-4 mRNA and protein along the intestinal tract and with a lower acyl-CoA synthetase activity in Hnf-4 alpha(int Delta) mice compared with the control mice. We conclude that the transcription factor Hnf-4 alpha is a key factor of the intestinal absorption of dietary lipids, which controls this process as early as in the initial step of fatty acid uptake by enterocytes.