Glucocorticoid regulation and glycosylation of mouse intestinal type IIb Na-P(i) cotransporter during ontogeny.
We sought to characterize expression of an apically expressed intestinal Na-P(i) cotransporter (Na-P(i)-IIb) during mouse ontogeny and to assess the effects of methylprednisolone (MP) treatment. In control mice, Na-P(i) uptake by intestinal brush-border membrane vesicles was highest at 14 days of age, lower at 21 days, and further reduced at 8 wk and 8-9 mo of age. Na-P(i)-IIb mRNA and immunoreactive protein levels in 14-day-old animals were markedly higher than in older groups. MP treatment significantly decreased Na-P(i) uptake and Na-P(i)-IIb mRNA and protein expression in 14-day-old mice. Additionally, the size of the protein was smaller in 14-day-old mice. Deglycosylation of protein from 14-day-old and 8-wk-old animals with peptide N-glycosidase reduced the molecular weight to the predicted size. We conclude that intestinal Na-P(i) uptake and Na-P(i)-IIb expression are highest at 14 days and decrease with age. Furthermore, MP treatment reduced intestinal Na-P(i) uptake approximately threefold in 14-day-old mice and this reduction correlates with reduced Na-P(i)-IIb mRNA and protein expression. We also demonstrate that Na-P(i)-IIb is an N-linked glycoprotein and that glycosylation is age dependent.
Department of Pediatrics, Steele Memorial Children's Research Center, University of Arizona Health Sciences Center, Tucson 85724, USA.
Kayo
K
Arima
Eric R
ER
Hines
Pawel R
PR
Kiela
Jason B
JB
Drees
James F
JF
Collins
Fayez K
FK
Ghishan
D000375:Aging / Q000502:physiology*; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D000833:Animals, Suckling / Q000502:physiology; D015152:Blotting, Northern; D006026:Glycoside Hydrolases / Q000494:pharmacology; D006031:Glycosylation; D007106:Immune Sera / Q000276:immunology; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D008775:Methylprednisolone / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008871:Microvilli / Q000378:metabolism; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000276:immunology / Q000378:metabolism; D050608:Sodium-Phosphate Cotransporter Proteins; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb; D027981:Symporters / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014886:Weaning
D007106:Immune Sera; D020033:Protein Isoforms; C493558:Slc34a2 protein, mouse; D050608:Sodium-Phosphate Cotransporter Proteins; D050614:Sodium-Phosphate Cotransporter Proteins, Type IIb; D027981:Symporters; D006026:Glycoside Hydrolases; D008775:Methylprednisolone