Proinflammatory actions of thromboxane receptors to enhance cellular immune responses.

Published

Journal Article

Metabolism of arachidonic acid by the cyclo-oxygenase (COX) pathway generates a family of prostanoid mediators. Nonsteroidal anti-inflammatory drugs (NSAIDs) act by inhibiting COX, thereby reducing prostanoid synthesis. The efficacy of these agents in reducing inflammation suggests a dominant proinflammatory role for the COX pathway. However, the actions of COX metabolites are complex, and certain prostanoids, such as PGE(2), in some circumstances actually inhibit immune and inflammatory responses. In these studies, we examine the hypothesis that anti-inflammatory actions of NSAIDs may be due, in part, to inhibition of thromboxane A(2) synthesis. To study the immunoregulatory actions of thromboxane A(2), we used mice with a targeted disruption of the gene encoding the thromboxane-prostanoid (TP) receptor. Both mitogen-induced responses and cellular responses to alloantigen were substantially reduced in TP(-/-) spleen cells. Similar attenuation was observed with pharmacological inhibition of TP signaling in wild-type splenocytes, suggesting that reduced responsiveness was not due to subtle developmental abnormalities in the TP-deficient mice. The absence of TP receptors reduced immune-mediated tissue injury following cardiac transplant rejection, an in vivo model of intense inflammation. Taken together, these findings show that thromboxane augments cellular immune responses and inflammatory tissue injury. Specific inhibition of the TP receptor may provide a more precise approach to limit inflammation without some of the untoward effects associated with NSAIDs.

Full Text

Duke Authors

Cited Authors

  • Thomas, DW; Rocha, PN; Nataraj, C; Robinson, LA; Spurney, RF; Koller, BH; Coffman, TM

Published Date

  • December 15, 2003

Published In

Volume / Issue

  • 171 / 12

Start / End Page

  • 6389 - 6395

PubMed ID

  • 14662837

Pubmed Central ID

  • 14662837

International Standard Serial Number (ISSN)

  • 0022-1767

Digital Object Identifier (DOI)

  • 10.4049/jimmunol.171.12.6389

Language

  • eng

Conference Location

  • United States