title: Altered endothelial nitric oxide synthase targeting and conformation and caveolin-1 expression in the diabetic kidney.
abstract: Experimental diabetes is associated with complex changes in renal nitric oxide (NO) bioavailability. We explored the effect of diabetes on renal cortical protein expression of endothelial NO synthase (eNOS) with respect to several determinants of its enzymatic function, such as eNOS expression, membrane localization, phosphorylation, and dimerization, in moderately hyperglycemic streptozotocin-induced diabetic rats compared with nondiabetic control rats and diabetic rats with intensive insulin treatment to achieve near-normal metabolic control. We studied renal cortical expression and localization of caveolin-1 (CAV-1), an endogenous modulator of eNOS function. Despite similar whole-cell eNOS expression in all groups, eNOS monomer and dimer in membrane fractions were reduced in moderately hyperglycemic diabetic rats compared with control rats; the opposite trend was apparent in the cytosol. Stimulatory phosphorylation of eNOS (Ser1177) was also reduced in moderately hyperglycemic diabetic rats. eNOS colocalized and interacted with CAV-1 in endothelial cells throughout the renal vascular tree both in control and moderately hyperglycemic diabetic rats. However, the abundance of membrane-localized CAV-1 was decreased in diabetic kidneys. Intensive insulin treatment reversed the effects of diabetes on each of these parameters. In summary, we observed diabetes-mediated alterations in eNOS and CAV-1 expression that are consistent with the view of decreased bioavailability of renal eNOS-derived NO.
authors.affiliation: Division of NephrologyHypertension PP262, Oregon Health and Science University, 3314 SW US Veterans Hospital Rd., Portland, OR 97239, USA. komersr@ohsu.edu
authors.forename: Radko
authors.initials: R
authors.lastname: Komers
authors.forename: William E
authors.initials: WE
authors.lastname: Schutzer
authors.forename: John F
authors.initials: JF
authors.lastname: Reed
authors.forename: Jessie N
authors.initials: JN
authors.lastname: Lindsley
authors.forename: Terry T
authors.initials: TT
authors.lastname: Oyama
authors.forename: David C
authors.initials: DC
authors.lastname: Buck
authors.forename: Scott L
authors.initials: SL
authors.lastname: Mader
authors.forename: Sharon
authors.initials: S
authors.lastname: Anderson
mesh_terms: D000818:Animals; D015153:Blotting, Western; D051242:Caveolin 1 / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007328:Insulin / Q000494:pharmacology; D007668:Kidney / Q000378:metabolism*; D008297:Male; D018613:Microscopy, Confocal; D052250:Nitric Oxide Synthase Type III / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin
chemical_list: D051242:Caveolin 1; D007004:Hypoglycemic Agents; D007328:Insulin; D013311:Streptozocin; D052250:Nitric Oxide Synthase Type III