title: Fibrillar collagen type I stimulation of apolipoprotein B secretion in Caco-2 cells is mediated by beta1 integrin.
abstract: Caco-2 cells spontaneously differentiate into enterocyte-like cells and secrete apolipoprotein B (apoB) lipoproteins. We evaluated the effect of different extracellular matrix proteins on lipoprotein secretion by these cells. Caco-2 cells grown on human amnion connective tissue (HACT) secreted twice as much apoB as control cells on Transwells, but secreted similar amounts of apoA1. Cells cultured on fibrillar collagen type I secreted increased amounts of apoB similar to the cells cultured on HACT, but cells cultured on non-fibrillar collagen type I, type IV collagen or laminin-1 did not. The increased secretion was nullified by a function inhibiting anti-integrin beta1 monoclonal antibody. Therefore, interactions between type I collagen and beta1 integrins augment apoB secretion by Caco-2 cells. Cells on HACT formed a more uniform columnar epithelium with lipid droplets polarized to the basolateral membrane. We also studied the effect of extracellular matrix proteins on transepithelial resistance (TER) of differentiated Caco-2 cells. TER in cells cultured on HACT was similar to that on Transwells, but cells on laminin-1 and collagen IV exhibited higher TER. Thus, various extracellular matrix proteins regulate apoB secretion and TER differently. This new observation that extracellular matrix proteins can enhance apoB secretion in Caco-2 cells could be useful to explore the modulation of lipid transport by these proteins.
authors: Department of Anatomy, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA.
authors: Don R
authors: DR
authors: Ratcliffe
authors: Jahangir
authors: J
authors: Iqbal
authors: M Mahmood
authors: MM
authors: Hussain
authors: Eva B
authors: EB
authors: Cramer
mesh_terms: D000650:Amnion / Q000166:cytology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D016632:Apolipoprotein A-I / Q000378:metabolism; D001055:Apolipoproteins B / Q000378:metabolism*; D018938:Caco-2 Cells; D002352:Carrier Proteins / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D024042:Collagen Type I / Q000494:pharmacology*; D003238:Connective Tissue / Q000187:drug effects / Q000378:metabolism; D017097:Electric Impedance; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats
chemical_list: D000911:Antibodies, Monoclonal; D016632:Apolipoprotein A-I; D001055:Apolipoproteins B; D002352:Carrier Proteins; D024042:Collagen Type I; D016326:Extracellular Matrix Proteins; D019012:Integrin beta1; D047428:Protein Kinase Inhibitors; C106092:microsomal triglyceride transfer protein