Heme oxygenase-1 deficiency leads to alteration of soluble guanylate cyclase redox regulation.
Heme oxygenase-1 knockout, H(mox)1(-/-), mice exhibit exacerbated vascular lesions after ischemia-reperfusion and mechanical injury. Surprisingly, we found no studies that reported contractile responses and sensitivity to vasorelaxants in H(mox)1(-/-) mice. The contractile responses [superior mesenteric arteries (SMA), from female H(mox)1(-/-) mice] exhibited increased sensitivity to phenylephrine (p < 0.001). Cumulative addition of acetylcholine relaxed SMA, with the residual contraction remaining 2 times higher in H(mox)1(-/-) mice (p < 0.001). Sodium nitroprusside (SNP, an NO donor) and 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole [YC-1; acts directly on soluble guanylate cyclase (sGC)] led to further relaxation, yet the residual contraction remained 2 to 3 times higher in H(mox)1(-/-) than H(mox)1(+/+) mice (p < 0.001). Branches from H(mox)1(-/-) mesenteric and renal arteries also showed reduced relaxation (p < 0.025). Relaxation of SMA was measured to 4-({(4-carboxybutyl) [2-(5-fluoro-2-{[4'-(trifluoromethyl) biphenyl-4-yl] methoxy}phenyl)ethyl]amino}benzoic acid (BAY 60-2770), which is a more effective activator of oxidized/heme-free sGC; and to 5-cyclopropyl-2-{1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl}-pyrimidin-4-ylamine (BAY 41-2272), a more effective stimulator of reduced sGC. H(mox)1(-/-) arteries were 15 times more sensitive to BAY 60-2770 (p < 0.025) than were H(mox)1(+/+) arteries. Pretreatment with 1H-[1,2,4]oxadiazolo[3,4-a]quinoxalin-1-one (ODQ), an oxidizer of sGC, predictably shifted the BAY 60-2770 response of H(mox)1(+/+) to the left (p < 0.01) and BAY 41-2272 response to the right (p < 0.01). ODQ had little effect on the responses of H(mox)1(-/-) arteries, indicating that much of sGC was oxidized/heme-free. Western analyses of sGC in SMA indicated that both α1 and β1 subunit levels were reduced to <50% of H(mox)1(+/+) level (p < 0.025). These findings support the hypothesis that the antioxidant function of H(mox)1 plays a significant role in the maintenance of sGC in a reduced state, which is resistant to degradation and is sensitive to NO. This function may be especially important in reducing vascular damage during ischemia-reperfusion injury.
Jones
Allan W
AW
Department of Medical Pharmacology, and Physiology, University of Missouri-Columbia, Columbia, MO 65212, USA. jonesa@health.missouri.edu
Durante
William
W
Korthuis
Ronald J
RJ
D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism; D015153:Blotting, Western; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006162:Guanylate Cyclase / Q000096:biosynthesis / Q000378:metabolism*; D006418:Heme / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000172:deficiency* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010084:Oxidation-Reduction; D010656:Phenylephrine / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis / Q000378:metabolism*; D000071756:Soluble Guanylyl Cyclase; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D004791:Enzyme Inhibitors; D009566:Nitrates; D020030:Nitric Oxide Donors; D018160:Receptors, Cytoplasmic and Nuclear; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D006418:Heme; D051547:Heme Oxygenase-1; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D000109:Acetylcholine