Oral Presentations - Pathology and Laboratory Medicine - University ...

Graduate StudentBillie Velapatiño 1 and David P Speert 21Departments of Pathology and Laboratory Medicine and 2 Pediatrics, University of BritishColumbia, Vancouver, British Columbia, CanadaAbstract # 68Billie Velapatiñothe activation of the phosphatidyl-inositol-3 kinasepathway in response to the burkholderia cepacia complexinfectionBackround/ObjectivesCystic fibrosis (CF) is the most common fatal inherited disease in North America and bacterial infection is theleading cause of death in these patients. Infections with the Burkholderia cepacia complex (Bcc) can result in rapiddecline in lung function and death. Whithin the species of the Bcc, B. cenocepacia (Bc) causes more severe infectionsthan B. multivorans (Bm), however the mechanism behind this difference in virulence remains undetermined. Weinvestigated the signaling events, specifically in the phosphoinositide3-kinase (PI3K) signaling pathway after bacterialhostinteraction to determine if measures of cellular activation are associated with the differential virulence andpersistence of these bacteria in infected host cells in CF patients.MethodsCF bronchial epithelial cell line (IB3-1), THP-1 derived macrophages and human monocyte-derived MΦswere infected with Bc and Bm. Lysates from infected and uninfected cells were analyzed by Western blot or byimmunoprecipitation using the appropriate antibodies.ResultsThe activation of the PI3K pathway occurred in IB3-1, in THP-1 derived macrophages and in human monocytederivedmacrophages after infection with live Bc. PI3K was not activated by Bc-LPS in IB3-1 cells but only with liveBc, and this activation was seen up to 3 hours after bacterial challenge. PI3K activation was faster in Bm (5 min) thanBc (30 min) after infection in macrophages. Activation of PI3K was abolished after infection with PI3K inhibitors.The release of TNF-α in macrophages infected with Bc and Bm in the presence of PI3K inhibitor was decreased.ConclusionThe PI3K signaling pathway is activated in response to the Bcc in both macrophages and epithelial cells. Bm showeda more rapid phosphorylation after infection as compare to Bc in macrophages. Current studies are in progress tocorrelate the rate of PI3K phosphorylation with cell death via apoptosis or necrosis assays.This work was supported by a grant from the Canadian Cystic Fibrosis Foundation (to D.P.S.).Poster Presentations * 2 0 1 079