B-188. Effect of LPS on Gb3 Expression in Murine Tissues

G. Kolling, F. Obata, L. Gross, T. Obrig;
Univ. of Virginia, Charlottesville, VA.

Shiga Toxin-producing Escherichia coli (STEC) cause hemorrhagic colitis and more severely, the hemolytic uremic syndrome (HUS). During gastrointestinal infection, the host is exposed to STEC virulence factors including Shiga toxin (Stx) and lipopolysaccharide (LPS). Shiga toxin binds to globotriaoslyceramide on the host cell membrane, is endocytosed, and eventually halts protein synthesis resulting in cell death. On the other hand, LPS initiates a potent inflammatory response involving cytokine release. In vitro, both LPS and pro-inflammatory cytokines increase cellular Gb3 thereby increasing cell sensitivity to Stx. Currently, there is no in vivo data showing the effect of LPS on global Gb3 expression. Therefore, Gb3 levels were examined in tissues from LPS treated mice using thin-layer chromatography in conjunction with toxin overlay. Lipids isolated from murine tissues revealed the presence of Gb3 in the kidneys, lungs, descending colon, and spleen. In the aforementioned tissues, Gb3 levels appeared unaltered after LPS treatment. Preliminary studies of cells isolated from whole blood suggest that platelets and leukocytes contain Gb3. Ongoing confocal microscopy experiments will demonstrate whether LPS augments cellular levels of Gb3 in the kidney. The results presented here will be useful in determining the contributions of LPS during the progression of HUS in a murine model. Moreover, the presence of Gb3 on platelets and/or leukocytes may clarify the role of circulating cells in disease pathogenesis.