The cultured human gastric cells HGT-1 express the principal transporters involved in acid secretion.
HGT-1 is a human cell line sharing a number of physiological features with gastric parietal cells. HGT-1 cell monolayers were able to secrete H+ when stimulated with histamine (calculated external pH variation, deltapH(e) 0.46+/-0.05) as assessed using the impermeant, pH-sensitive fluorescence dye 8-hydroxypyrene-1,3,6-trisulphonic acid, trisodium salt (HPTS). Treatment with 100 microM omeprazole inhibited the histamine-induced apical acidification by about 60%. Intracellular pH (pH(i)) measurements using the fluorescent pH-sensitive dye 2',7'-bis-carboxyethyl-5(6)-carboxyfluorescein (BCECF) demonstrated the expression of a functional, omeprazole-sensitive H+/K+-pump. A monoclonal antibody directed against the alpha subunit of the H+/K+-ATPase immunoprecipitated a 95-kDa protein from HGT-1 cells and human stomach which corresponds to the expected molecular size of the native protein. HGT-1 cells were also positive for the anion exchanger AE2 that is expressed in gastric parietal cells. In addition, we identified a histamine- and pH(i)-sensitive Na+/H+ exchanger in HGT-1 cells, which might correspond to the functional expression of the NHE4 isoform that has been detected in gastric epithelial cells as well as in primary cultured parietal cells. HGT-1 cells therefore display the principal features of parietal cells and might represent an interesting cell culture model for studying the regulatory mechanisms involved in acid secretion.
Carmosino
M
M
Dipartimento di Fisiologia Generale ed Ambientale, Bari, Italy.
Procino
G
G
Casavola
V
V
Svelto
M
M
Valenti
G
G
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000911:Antibodies, Monoclonal; D002460:Cell Line; D004396:Coloring Agents; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005452:Fluoresceins; D005455:Fluorescent Antibody Technique; D005744:Gastric Acid / Q000378:metabolism*; D017506:H(+)-K(+)-Exchanging ATPase / Q000276:immunology / Q000378:metabolism; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007163:Immunosorbent Techniques; D007700:Kinetics; D008954:Models, Biological; D009853:Omeprazole / Q000494:pharmacology; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D054328:Proton Pump Inhibitors; D012964:Sodium / Q000494:pharmacology; D019108:Tight Junctions / Q000648:ultrastructure
D000911:Antibodies, Monoclonal; D004396:Coloring Agents; D004791:Enzyme Inhibitors; D005452:Fluoresceins; D054328:Proton Pump Inhibitors; D000584:Amiloride; D006632:Histamine; C043829:2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; D012964:Sodium; D017506:H(+)-K(+)-Exchanging ATPase; D009853:Omeprazole; D015056:1-Methyl-3-isobutylxanthine