Transport of vitamin E by differentiated Caco-2 cells
| Autor: | M. Mahmood Hussain, Herbert J. Kayden, Kamran Anwar |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Vitamin
cholesteryl esters medicine.medical_specialty Vitamin D-binding protein medicine.medical_treatment microsomal triglyceride transfer protein QD415-436 Models Biological Biochemistry Microsomal triglyceride transfer protein chemistry.chemical_compound Endocrinology Internal medicine Chylomicrons medicine Humans Vitamin E Tocopherol Intestinal Mucosa triglycerides Apolipoproteins A phospholipids biology lipoprotein assembly Abetalipoproteinemia Biological Transport Cell Differentiation Cell Biology medicine.disease Intestines Chylomicron assembly chemistry biology.protein lipids (amino acids peptides and proteins) Cholesterol Esters Caco-2 Cells triacylglycerol Carrier Proteins Lipoproteins HDL Signal Transduction Chylomicron |
| Zdroj: | Journal of Lipid Research, Vol 47, Iss 6, Pp 1261-1273 (2006) |
| ISSN: | 0022-2275 |
| DOI: | 10.1194/jlr.m500523-jlr200 |
| Popis: | In hepatocytes, vitamin E is secreted via the efflux pathway and is believed to associate with apolipoprotein B (apoB)-lipoproteins extracellularly. The molecular mechanisms involved in the uptake, intracellular trafficking, and secretion of dietary vitamin E by the intestinal cells are unknown. We observed that low concentrations of Tween-40 were better for the solubilization and delivery of vitamin E to differentiated Caco-2 cells, whereas high concentrations of Tween-40 and sera inhibited this uptake. Vitamin E uptake was initially rapid and then reached saturation. Subcellular localization revealed that vitamin E primarily accumulated in microsomal membranes. Oleic acid (OA) treatment, which induces chylomicron assembly and secretion, decreased microsomal membrane-bound vitamin E in a time-dependent manner. To study secretion, differentiated Caco-2 cells were pulse-labeled with vitamin E and chased in the presence and absence of OA. In the absence of OA, vitamin E was associated with intestinal high density lipoprotein (I-HDL), whereas OA-treated cells secreted vitamin E with I-HDL and chylomicrons. No extracellular transfer of vitamin E between these lipoproteins was observed. Glyburide, an antagonist of ABCA1, partially inhibited its secretion with I-HDL, whereas plasma HDL increased vitamin E efflux. An antagonist of microsomal triglyceride transfer protein, brefeldin A, and monensin specifically inhibited vitamin E secretion with chylomicrons. These studies indicate that vitamin E taken up by Caco-2 cells is stored in the microsomal membranes and secreted with chylomicrons and I-HDL. Transport via I-HDL might contribute to vitamin E absorption in patients with abetalipoproteinemia receiving large oral doses of the vitamin. |
| Databáze: | OpenAIRE |
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