title: Genetic Ablation of the ClC-2 Cl- Channel Disrupts Mouse Gastric Parietal Cell Acid Secretion.
abstract: The present studies were designed to examine the effects of ClC-2 ablation on cellular morphology, parietal cell abundance, H/K ATPase expression, parietal cell ultrastructure and acid secretion using WT and ClC-2-/- mouse stomachs. Cellular histology, morphology and proteins were examined using imaging techniques, electron microscopy and western blot. The effect of histamine on the pH of gastric contents was measured. Acid secretion was also measured using methods and secretagogues previously established to give maximal acid secretion and morphological change. Compared to WT, ClC-2-/- gastric mucosal histological organization appeared disrupted, including dilation of gastric glands, shortening of the gastric gland region and disorganization of all cell layers. Parietal cell numbers and H/K ATPase expression were significantly reduced by 34% (P<0.05) and 53% (P<0.001) respectively and cytoplasmic tubulovesicles appeared markedly reduced on electron microscopic evaluation without evidence of canalicular expansion. In WT parietal cells, ClC-2 was apparent in a similar cellular location as the H/K ATPase by immunofluorescence and appeared associated with tubulovesicles by immunogold electron microscopy. Histamine-stimulated [H+] of the gastric contents was significantly (P<0.025) lower by 9.4 fold (89%) in the ClC-2-/- mouse compared to WT. Histamine/carbachol stimulated gastric acid secretion was significantly reduced (range 84-95%, P<0.005) in ClC-2-/- compared to WT, while pepsinogen secretion was unaffected. Genetic ablation of ClC-2 resulted in reduced gastric gland region, reduced parietal cell number, reduced H/K ATPase, reduced tubulovesicles and reduced stimulated acid secretion.
authors.affiliation: North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina, United States of America.
authors.forename: Meghali P
authors.initials: MP
authors.lastname: Nighot
authors.affiliation: North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina, United States of America.
authors.forename: Prashant K
authors.initials: PK
authors.lastname: Nighot
authors.affiliation: University of New Mexico School of Medicine, Albuquerque, New Mexico, United States of America.
authors.forename: Thomas Y
authors.initials: TY
authors.lastname: Ma
authors.affiliation: University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.
authors.forename: Danuta H
authors.initials: DH
authors.lastname: Malinowska
authors.affiliation: University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.
authors.forename: Gary E
authors.initials: GE
authors.lastname: Shull
authors.affiliation: University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America.
authors.forename: John
authors.initials: J
authors.lastname: Cuppoletti
authors.affiliation: North Carolina State University, College of Veterinary Medicine, Raleigh, North Carolina, United States of America.
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Blikslager
mesh_terms: D000818:Animals; D001692:Biological Transport; D000090007:CLC-2 Chloride Channels; D002452:Cell Count; D018118:Chloride Channels / Q000235:genetics*; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D004063:Digestion / Q000235:genetics / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D005744:Gastric Acid / Q000378:metabolism*; D017506:H(+)-K(+)-Exchanging ATPase / Q000096:biosynthesis* / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D010295:Parietal Cells, Gastric / Q000378:metabolism* / Q000648:ultrastructure; D020116:Pepsinogen A / Q000378:metabolism
chemical_list: D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; D020116:Pepsinogen A; D017506:H(+)-K(+)-Exchanging ATPase