Heme oxygenase/carbon monoxide-biliverdin pathway down regulates neutrophil rolling, adhesion and migration in acute inflammation.
OBJECTIVE
Heme oxygenase (HO) activity is known to down-regulate inflammatory events. Here, we address the role of HO and its metabolites, carbon monoxide (CO) and biliverdin (BVD), in leukocyte rolling, adhesion and neutrophil migration during inflammatory processes.


METHODS
Intravital microscopy was used to evaluate leukocyte rolling and adhesion in the mesenteric microcirculation of mice. TNFalpha and IL-1beta were determined by ELISA and HO-1 protein expression by Western blot.


RESULTS
Intraperitoneal challenge with carrageenan enhanced HO-1 protein expression in mesentery and bilirubin concentration in peritoneal exudates. Pretreatment of mice with a non-specific inhibitor of HO (ZnDPBG) or with a HO-1 specific inhibitor (ZnPP IX) enhanced neutrophil migration, rolling and adhesion on endothelium induced by carrageenan. In contrast, HO substrate (hemin), CO donor (DMDC) or BVD reduced these parameters. The reduction of neutrophil recruitment promoted by HO metabolites was independent of the production of chemotactic cytokines. Inhibitory effects of CO, but not of BVD, were counteracted by treatment with a soluble guanylate cyclase (sGC) inhibitor, ODQ. Furthermore, inhibition of HO prevented the inhibitory effect of a nitric oxide (NO) donor (SNAP) upon neutrophil migration, while the blockade of NO synthase (NOS) activity by aminoguanidine did not affect the CO or BVD effects.


CONCLUSIONS
Metabolites of HO decreased leukocyte rolling, adhesion and neutrophil migration to the inflammatory site by a mechanism partially dependent on sGC. Moreover, inhibition by NO of neutrophil migration was dependent on HO activity.
Freitas
A
A
Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo, São Paulo, Brazil.
Alves-Filho
J C
JC
Secco
D D
DD
Neto
A F
AF
Ferreira
S H
SH
Barja-Fidalgo
C
C
Cunha
F Q
FQ
D000818:Animals; D001664:Biliverdine / Q000494:pharmacology*; D002248:Carbon Monoxide / Q000494:pharmacology*; D002351:Carrageenan; D002448:Cell Adhesion / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects*; D003905:Deuteroporphyrins / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006427:Hemin / Q000494:pharmacology; D007249:Inflammation / Q000097:blood / Q000139:chemically induced / Q000201:enzymology*; D053583:Interleukin-1beta / Q000097:blood; D036904:Leukocyte Rolling / Q000187:drug effects*; D008642:Mesenteric Veins; D051379:Mice; D008807:Mice, Inbred BALB C; D018715:Microscopy, Video; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology; D009569:Nitric Oxide / Q000378:metabolism; D011524:Protoporphyrins / Q000494:pharmacology; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D003905:Deuteroporphyrins; D004791:Enzyme Inhibitors; D053583:Interleukin-1beta; D011524:Protoporphyrins; D018160:Receptors, Cytoplasmic and Nuclear; D014409:Tumor Necrosis Factor-alpha; C060750:zinc deuteroporphyrin IX 2,4-bis(glycol); C017803:zinc protoporphyrin; D009569:Nitric Oxide; D006427:Hemin; D002248:Carbon Monoxide; D002351:Carrageenan; D006419:Heme Oxygenase (Decyclizing); D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D001664:Biliverdine