Acute-phase protein α-1-acid glycoprotein mediates neutrophil migration failure in sepsis by a nitric oxide-dependent mechanism

doi:10.1073/pnas.0709681104

Acute-phase protein α-1-acid glycoprotein mediates neutrophil migration failure in sepsis by a nitric oxide-dependent mechanism

Departments of *Pharmacology,
^‖Cellular and Molecular Biology and Pathogenic Agents, and
^§Surgery and Anatomy and
^†Protein Chemistry Center, Faculty of Medicine of Ribeirão Preto, University of São Paulo,14049-900 Ribeirao Preto, São Paulo, Brazil;
^‡Hemocenter Foundation of Ribeirão Preto, 14049-900 Ribeirão Preto, São Paulo, Brazil; and
^¶Department of Biological Sciences, Federal University of Triângulo Mineiro, 38025-180 Uberaba, Minas Gerais, Brazil

Contributed by S. H. Ferreira, October 14, 2007 (received for review June 20, 2007)

Abstract

The reduction of circulating neutrophil migration to infection sites is associated with a poor outcome of severe sepsis. α-1-Acid glycoprotein (AGP) was isolated from the sera of severely septic patients by HPLC and acrylamide gel electrophoresis and identified by mass spectrometry. Both the isolated protein and commercial AGP inhibited carrageenin-induced neutrophil migration into the rat peritoneal cavity when administered i.v. at a dose of 4.0 μg per rat (95 pmol per rat). Analysis by intravital microscopy demonstrated that both proteins inhibited the rolling and adhesion of leukocytes in the mesenteric microcirculation. The inhibitory activity was blocked by 50 mg/kg aminoguanidine, s.c., and was not demonstrable in inducible nitric oxide synthase (iNOS) knockout mice. Incubation of AGP with neutrophils from healthy subjects induced the production of NO and inhibited the neutrophil chemotaxis by an iNOS/NO/cyclic guanosine 3,5-monophosphate-dependent pathway. In addition, AGP induced the l-selectin shedding by neutrophils. The administration of AGP to rats with mild cecal ligation puncture sepsis inhibited neutrophil migration and reduced 7-day survival from ≈80% to 20%. These data demonstrate that AGP, an acute-phase protein, inhibits neutrophil migration by an NO-dependent process and suggest that AGP also participates in human sepsis.

Footnotes

**To whom correspondence should be addressed at:
Department of Pharmacology, Faculty of Medicine of Ribeirao Preto, University of Sao Paulo, Avenida dos Bandeirantes 3900, 14049-900 Ribeirao Preto, SP, Brazil.
E-mail: shferrei{at}fmrp.usp.br
Author contributions: F.L.A.C.M., F.S., and H.J.L. contributed equally to the work; F.S., B.M.T.-M., S.H.F., L.J.G., and F.Q.C. designed research; F.L.A.C.M., F.S., H.J.L., F.O.S., and J.C.R. performed research; J.C.R., A.B.-F., S.H.F., L.J.G., and F.Q.C. contributed new reagents/analytic tools; F.S., J.C.R., L.J.G., and F.Q.C. analyzed data; and F.L.M., F.S., L.J.G., and F.Q.C. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0709681104/DC1.