Expression of nitric oxide synthase isoforms in the mouse kidney: cellular localization and influence by lipopolysaccharide and Toll-like receptor 4.
We determined the cellular mRNA expression of all intrarenal nitric oxide (NO)-producing NO synthase (NOS) isoforms, endothelial NOS (eNOS) and neuronal NOS (nNOS) and inducible NOS (iNOS) in kidneys from wild-type mice (WT) and immune deficient Toll-like receptor 4 (TLR4) mutant mice, during normal physiological conditions and during a short-term (6-16 h) endotoxic condition caused by systemically administered lipopolysaccaride (LPS). Investigations were performed by means of in situ hybridization and polymerase chain reaction amplification techniques. In WT, LPS altered the expression rate of all intrarenal NOS isoforms in a differentiated but NOS-isoform coupled expression pattern, with iNOS induction, and up- and down-regulation of the otherwise constitutively expressed NOS isoforms, e.g. eNOS and nNOS and an iNOS isotype. In TLR4 mutants, LPS caused none or a lowered iNOS induction, but altered the expression rate of the constitutive NOS isoforms. It is concluded that the intrarenal spatial relation of individual NOS-isoforms and their alteration in expression provide the basis for versatile NO-mediated renal actions that may include local interactions between NOS isoforms and their individual NO-target sites, and that the NOS-isoform dependent events are regulated by TLR4 during endotoxic processes. These regulatory mechanisms are likely to participate in different pathophysiological conditions affecting NO-mediated renal functions.
Holmqvist
Bo
B
Department of Pathology, Inst. Medical Sciences, Lund University, Lund, Sweden. bo.holmqvist@med.lu.se
Olsson
Christina Falk
CF
Svensson
Maj-Lis
ML
Svanborg
Catharina
C
Forsell
Johan
J
Alm
Per
P
D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D017403:In Situ Hybridization; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D019001:Nitric Oxide Synthase / Q000235:genetics* / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D051197:Toll-Like Receptor 4 / Q000172:deficiency / Q000378:metabolism*
D008070:Lipopolysaccharides; D020033:Protein Isoforms; D012333:RNA, Messenger; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III