Transport of vitamin E by differentiated Caco-2 cells
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...
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| Format: | Article |
| Language: | English |
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Elsevier
2006-06-01
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| Series: | Journal of Lipid Research |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520332259 |
| _version_ | 1818602528746504192 |
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| author | Kamran Anwar Herbert J. Kayden M. Mahmood Hussain |
| author_facet | Kamran Anwar Herbert J. Kayden M. Mahmood Hussain |
| author_sort | Kamran Anwar |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-16T13:08:43Z |
| format | Article |
| id | doaj.art-0ccb30c5db3f4f72b2cf250afd822400 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-16T13:08:43Z |
| publishDate | 2006-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-0ccb30c5db3f4f72b2cf250afd8224002022-12-21T22:30:41ZengElsevierJournal of Lipid Research0022-22752006-06-0147612611273Transport of vitamin E by differentiated Caco-2 cellsKamran Anwar0Herbert J. Kayden1M. Mahmood Hussain2Departments of Anatomy & Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NYNew York University Medical Center, New York, NYDepartments of Anatomy & Cell Biology and Pediatrics, State University of New York Downstate Medical Center, Brooklyn, NYIn 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.http://www.sciencedirect.com/science/article/pii/S0022227520332259microsomal triglyceride transfer proteinlipoprotein assemblytriglyceridescholesteryl estersphospholipidstriacylglycerol |
| spellingShingle | Kamran Anwar Herbert J. Kayden M. Mahmood Hussain Transport of vitamin E by differentiated Caco-2 cells Journal of Lipid Research microsomal triglyceride transfer protein lipoprotein assembly triglycerides cholesteryl esters phospholipids triacylglycerol |
| title | Transport of vitamin E by differentiated Caco-2 cells |
| title_full | Transport of vitamin E by differentiated Caco-2 cells |
| title_fullStr | Transport of vitamin E by differentiated Caco-2 cells |
| title_full_unstemmed | Transport of vitamin E by differentiated Caco-2 cells |
| title_short | Transport of vitamin E by differentiated Caco-2 cells |
| title_sort | transport of vitamin e by differentiated caco 2 cells |
| topic | microsomal triglyceride transfer protein lipoprotein assembly triglycerides cholesteryl esters phospholipids triacylglycerol |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520332259 |
| work_keys_str_mv | AT kamrananwar transportofvitaminebydifferentiatedcaco2cells AT herbertjkayden transportofvitaminebydifferentiatedcaco2cells AT mmahmoodhussain transportofvitaminebydifferentiatedcaco2cells |