Splice variants of neuronal nitric oxide synthase are present in the rat kidney.
BACKGROUND
Decreased renal cortical neuronal NO synthase (nNOS) abundance/activity correlates with progression of chronic kidney disease (CKD) in a number of animal models.


METHODS
Western blotting with both N-terminal and C-terminal antibodies, immunoprecipitation, proteomics, RT-PCR and in situ hybridization were used to identify nNOS splice variants in the rat kidney.


RESULTS
We have identified two nNOS proteins and transcripts in the rat kidney; nNOSalpha (approximately 160 kDa) and nNOSbeta (approximately 140 kDa), a catalytically active exon-2 deletion variant, lacking both the PDZ and protein inhibitor of nNOS (PIN) domains. We also report that nNOSbeta protein abundance is increased in the kidney at 11 weeks following 5/6th nephrectomy (5/6NX)-induced CKD while nNOSalpha protein abundance is diminished. The transcript data parallel the protein data in 5/6NX. By in situ hybridization, there is abundant nNOSalpha mRNA widely distributed throughout the normal kidney cortex, with very sparse nNOSbeta mRNA confined to a few proximal tubules. In a second injury model (6 weeks after 5/6 renal mass reduction by combined right kidney ablation and infarction of approximately 2/3 of the left kidney; 5/6 A/I), nNOSalpha mRNA almost disappears from the kidney cortex while nNOSbeta mRNA abundance increases in tubules and tubulo-interstitium.


CONCLUSIONS
The renal cortical nNOSbeta protein is present in low abundance in the normal kidney and increases with injury, in an inverse pattern of change with the nNOSalpha.
Smith
Cheryl
C
Department of Physiology and Functional Genomics, University of Florida, POB 100274, Gainesville, FL 36210, USA.
Merchant
Michael
M
Fekete
Andrea
A
Nyugen
Ha-Long
HL
Oh
Paul
P
Tain
You-Lin
YL
Klein
Jon B
JB
Baylis
Chris
C
D000818:Animals; D002908:Chronic Disease; D004195:Disease Models, Animal; D005260:Female; D014644:Genetic Variation / Q000235:genetics; D007527:Isoenzymes / Q000378:metabolism; D007672:Kidney Cortex / Q000201:enzymology*; D007674:Kidney Diseases / Q000201:enzymology*; D008297:Male; D009392:Nephrectomy; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats
D007527:Isoenzymes; D020033:Protein Isoforms; D012333:RNA, Messenger; D052248:Nitric Oxide Synthase Type I