Neuronal nitric oxide synthase (NOS) regulates leukocyte-endothelial cell interactions in endothelial NOS deficient mice.
1. The present study was designed to examine the possible role of neuronal nitric oxide synthase (nNOS) in regulation of leukocyte - endothelial cell interactions in the absence of endothelial nitric oxide synthase (eNOS), using intravital microscopy of the cremasteric microcirculation of eNOS(-/-) mice. 2. Baseline leukocyte rolling and adhesion revealed no differences between wild-type and eNOS(-/-) mice in either the cremasteric or intestinal microcirculations. 3. Superfusion with L-NAME (100 microM) caused a progressive and significant increase in leukocyte adhesion in both wild-type and eNOS(-/-) mice, without detecting differences between the two strains of mice. 4. Superfusion with 7-nitroindazole (100 microM), a selective inhibitor of nNOS, had no effect on leukocyte adhesion in wild-type animals. However, it increased leukocyte adhesion significantly in eNOS(-/-) mice, which was reversed by systemic L-arginine pre-administration. 5. Stimulation of the microvasculature with H(2)O(2) (100 microM) induced a transient elevation in leukocyte rolling in wild-type mice. Conversely, the effect persisted during the entire 60 min of experimental protocol in eNOS(-/-) mice either with or without 7-nitroindazole. 6. Semi-quantitative analysis by RT - PCR of the mRNA for nNOS levels in eNOS(-/-) and wild-type animals, showed increased expression of nNOS in both brain and skeletal muscle of eNOS(-/-) mice. 7. In conclusion, we have demonstrated that leukocyte-endothelial cell interactions are predominantly modulated by eNOS isoform in postcapillary venules of normal mice, whereas nNOS appears to assume the same role in eNOS(-/-) mice. Interestingly, unlike eNOS there was insufficient NO produced by nNOS to overcome leukocyte recruitment elicited by oxidative stress, suggesting that nNOS cannot completely compensate for eNOS.
Sanz
M J
MJ
Immunology Research Group, University of Calgary, Calgary, Alberta T2N 4N1, Canada. maria.j.sanz@uv.es
Hickey
M J
MJ
Johnston
B
B
McCafferty
D M
DM
Raharjo
E
E
Huang
P L
PL
Kubes
P
P
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D005838:Genotype; D006439:Hemodynamics; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007191:Indazoles / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000098:blood supply; D007962:Leukocytes / Q000166:cytology* / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000098:blood supply; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D052248:Nitric Oxide Synthase Type I; D016877:Oxidants / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014699:Venules / Q000502:physiology
D004791:Enzyme Inhibitors; D007191:Indazoles; D016877:Oxidants; D012333:RNA, Messenger; D001120:Arginine; D006861:Hydrogen Peroxide; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; C496321:Nos1 protein, mouse; C080122:7-nitroindazole; D019331:NG-Nitroarginine Methyl Ester