Potential roles for regulatory oxygenases in rickettsial pathogenesis.

Sanjeev Sahni, Elena Rydkina, Abha Sahni, Suresh G. Joshi, David J. Silverman

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Clinical and experimental evidence suggests an important role for oxidative stress and associated cellular defense mechanisms in the pathogenesis of vasculopathic rickettsioses. Our laboratory has reported that R. rickettsii infection of endothelial cells in vitro induces the expression of HO-1, the inducible isoform of the antioxidant defense enzyme heme oxygenase. HO-1 plays a critical role in maintaining the integrity of the vasculature and controls the functioning of the cyclooxygenase (COX) system. This study was undertaken to investigate the expression of COX and HO isozymes during in vitro infection of EC with two major representatives of spotted fever group Rickettsia species. The mRNA expression of COX-2 was significantly increased in endothelial cells infected with R. rickettsii and R. conorii, while that of COX-1 remained unaffected. Western blot analysis using total protein lysates from infected endothelial cells and corresponding uninfected controls further confirmed specific induction of COX-2 in response to infection. ELISA measurements on culture supernatants also suggested enhanced secretion of 6-keto PGF(1alpha) (stable hydrolysis product of PGI(2) and PGE(2). As a functional consequence of HO-1 upregulation, increased expression of the iron storage protein ferritin following R. rickettsii and R. conorii infection was also evident. Since products of HO-1 and COX-2 reactions govern a variety of physiologically important functions in the vasculature, further studies to define their regulation in the host cell should provide useful insights into the pathogenesis of rickettsial diseases.

Original languageEnglish (US)
Pages (from-to)207-214
Number of pages8
JournalAnnals of the New York Academy of Sciences
Volume1063
DOIs
StatePublished - Dec 2005
Externally publishedYes

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Oxygenases
Endothelial cells
Cyclooxygenase 2
Prostaglandin-Endoperoxide Synthases
Endothelial Cells
Infection
Heme Oxygenase (Decyclizing)
Cyclooxygenase 1
Oxidative stress
Prostaglandins F
Ferritins
Prostaglandins E
Rickettsia
Isoenzymes
Hydrolysis
Protein Isoforms
Proteins
Iron
Antioxidants
Messenger RNA

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Potential roles for regulatory oxygenases in rickettsial pathogenesis. / Sahni, Sanjeev; Rydkina, Elena; Sahni, Abha; Joshi, Suresh G.; Silverman, David J.

In: Annals of the New York Academy of Sciences, Vol. 1063, 12.2005, p. 207-214.

Research output: Contribution to journalArticle

Sahni, Sanjeev ; Rydkina, Elena ; Sahni, Abha ; Joshi, Suresh G. ; Silverman, David J. / Potential roles for regulatory oxygenases in rickettsial pathogenesis. In: Annals of the New York Academy of Sciences. 2005 ; Vol. 1063. pp. 207-214.
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