Lectin-like Ox-LDL receptor is expressed in human INT-407 intestinal cells: involvement in the transcytosis of pancreatic bile salt-dependent lipase.
We have recently shown that the pancreatic bile salt-dependent lipase (BSDL) can be taken up by intestinal cells and transported to the blood circulation. This mechanism likely involves (specific) receptor(s) able to bind BSDL and located at the apical intestinal cell membrane. In this study, using Int407 human intestinal cells cultured to form a tight epithelium, we attempted to characterize (the) BSDL receptor(s). We found that an apical 50-kDa protein was able to bind BSDL. Further, we have demonstrated that Int407 cells expressed the lectin-like oxidized-LDL receptor (LOX-1), the upregulation of which by oxidized-LDL potentiates the transcytosis of BSDL, whereas carrageenan and to a lesser extent polyinosinic acid and fucoidan decrease the enzyme transcytosis. The mAb JTX92, which blocks the LOX-1 receptor function, also impaired the BSDL transcytosis. To confirm these results, the cDNA encoding the human intestinal receptor LOX-1 has been cloned, inserted into vectors, and transfected into Int407 cells. Overexpression of LOX-1 by these cells leads to a substantial increase in the BSDL transcytosis. Globally, these data support the view that LOX-1 could be an intestinal receptor for BSDL, which is implicated in the transcytosis of this enzyme throughout Int407 cells.
Bruneau
Nadine
N
INSERM U-559, Unité de Recherche de Physiopathologie des Cellules Epithéliales and Equipe d'Accueil 3289, Université de la Méditerranée, Faculté de Médecine, Marseilles, France. nadine.brunewu@medecine.univ-mrs.fr
Richard
Stéphane
S
Silvy
Françoise
F
Verine
Alain
A
Lombardo
Dominique
D
D002460:Cell Line; D003001:Cloning, Molecular; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology; D008077:Lipoproteins, LDL / Q000378:metabolism; D011069:Poly I / Q000494:pharmacology; D011134:Polysaccharides / Q000494:pharmacology; D011485:Protein Binding; D011973:Receptors, LDL / Q000378:metabolism*; D051131:Receptors, Oxidized LDL; D051127:Scavenger Receptors, Class E; D002787:Sterol Esterase / Q000378:metabolism*; D014168:Transferrin / Q000378:metabolism
D008077:Lipoproteins, LDL; C495137:OLR1 protein, human; D011134:Polysaccharides; D011973:Receptors, LDL; D051131:Receptors, Oxidized LDL; D051127:Scavenger Receptors, Class E; D014168:Transferrin; C099252:oxidized low density lipoprotein; D011069:Poly I; C054784:bile salt-stimulated lipase; D002787:Sterol Esterase