Differential Regulation of Lipopolysaccharide and Gram-Positive Bacteria Induced Cytokine and Chemokine Production in Splenocytes by Gα_I Proteins

Creator(s)

Hongkuan Fan
David L. Williams, East Tennessee State UniversityFollow
Basilia Zingarelli, Cincinnati Children's Hospital Medical Center
Kevin F. Breuel, Quillen-Dishner College of MedicineFollow
Giuseppe Teti, Università degli Studi di Messina
George E. Tempel
Karsten Spicher, Heinrich-Heine-Universität Düsseldorf
Guylain Boulay, Université de Sherbrooke
Lutz Birnbaumer, National Institute of Environmental Health Sciences (NIEHS)
Perry V. Halushka, Medical University of South Carolina
James A. Cook

Document Type

Article

Publication Date

10-1-2006

Description

Heterotrimeric Gi proteins play a role in lipopolysaccharide (LPS) and Staphylococcus aureus (SA) activated signaling leading to inflammatory mediator production. We hypothesized that genetic deletion of Gi proteins would alter cytokine and chemokine production induced by LPS and SA. LPS- and heat killed SA-induced cytokine and chemokine production in splenocytes from wild type (WT), Gαi2 (-/-) or Gαi1/3 (-/-) mice were investigated. LPS- or SA-induced production of TNFα, IL-6, IFNγ, IL-12, IL-17, GM-CSF, MIP-1α, MCP-1, MIG and IP-10 were significantly increased (1.2 to 33 fold, p < 0.05) in splenocytes harvested from Gαi2(-/-) mice compared with WT mice. The effect of Gαi protein depletion was remarkably isoform specific. In splenocytes from Gαi1/3 (-/-) mice relative to WT mice, SA-induced IL-6, IFNγ, GM-CSF, and IP-10 levels were decreased (59% to 86%, p < 0.05), whereas other LPS- or SA-stimulated cytokines and chemokines were not different relative to WT mice. LPS- and SA-induced production of KC were unchanged in both groups of the genetic deficient mice. Splenocytes from both Gαi2 (-/-) and Gαi1/3 (-/-) mice did not exhibit changes in TLR2 and TLR4 expression. Also analysis of splenic cellular composition by flow cytometry demonstrated an increase in splenic macrophages and reduced CD4 T cells in both Gαi2 (-/-) and Gαi1/3 (-/-) mice relative to WT mice. The disparate response of splenocytes from the Gαi2 (-/-) relative to Gαi1/3 (-/-) mice therefore cannot be attributed to major differences in spleen cellular composition. These data demonstrate that Gi2 and Gi1/3 proteins are both involved and differentially regulate splenocyte inflammatory cytokine and chemokine production in a highly Gi isoform specific manner in response to LPS and Gram-positive microbial stimuli.

Citation Information

Fan, Hongkuan; Williams, David L.; Zingarelli, Basilia; Breuel, Kevin F.; Teti, Giuseppe; Tempel, George E.; Spicher, Karsten; Boulay, Guylain; Birnbaumer, Lutz; Halushka, Perry V.; and Cook, James A.. 2006. Differential Regulation of Lipopolysaccharide and Gram-Positive Bacteria Induced Cytokine and Chemokine Production in Splenocytes by Gα_I Proteins. Biochimica et Biophysica Acta - Molecular Cell Research. Vol.1763(10). 1051-1058. https://doi.org/10.1016/j.bbamcr.2006.08.003 PMID: 16962188 ISSN: 0167-4889