CXCL1/KC and CXCL2/MIP-2 are critical effectors and potential targets for therapy of Escherichia coli O157:H7-associated renal inflammation.
Neutrophilia is a characteristic of hemolytic uremic syndrome caused by Shiga toxin (Stx2)-producing Escherichia coli. However, the role of neutrophils in the toxin-induced renal injury occurring in enterohemorrhagic E. coli infection remains undefined. We report the trafficking of neutrophils to the kidney of C57BL/6 mice throughout a 72-hour time course after challenge with purified E. coli Stx2 and lipopolysaccharide (LPS). Increased neutrophils were observed in the renal cortex, particularly within the glomeruli where a more than fourfold increase in neutrophils was noted within 2 hours after challenge. Using microarray analysis, an increased number of transcripts for chemoattractants CXCL1/KC (69-fold at 2 hours) and CXCL2/MIP-2 (29-fold at 2 hours) were detected. Ribonuclease protection assays, Northern blotting, enzyme-linked immunosorbent assay, and immunohistochemistry confirmed microarray results, showing that both chemokines were expressed only on the immediate periglomerular epithelium and that these events coincided with neutrophil invasion of glomeruli. Co-administration of Stx2 with LPS enhanced and prolonged the KC and MIP-2 host response (RNA and protein) induced by LPS alone. Immunoneutralization in vivo of CXCL1/KC and CXCL2/MIP-2 abrogated neutrophil migration into glomeruli by 85%. These data define the molecular basis for neutrophil migration into the kidney after exposure to virulence factors of Shiga toxin-producing E. coli O157:H7.
Roche
James K
JK
Division of Nephrology, Department of Medicine, Box 800133, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA.
Keepers
Tiffany R
TR
Gross
Lisa K
LK
Seaner
Regina M
RM
Obrig
Tom G
TG
D000818:Animals; D002465:Cell Movement / Q000187:drug effects; D054360:Chemokine CXCL1; D054426:Chemokine CXCL2; D018925:Chemokines / Q000096:biosynthesis*; D019743:Chemokines, CXC / Q000096:biosynthesis*; D004927:Escherichia coli Infections / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D019453:Escherichia coli O157; D007249:Inflammation / Q000139:chemically induced / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D007678:Kidney Glomerulus / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D008070:Lipopolysaccharides / Q000633:toxicity; D008297:Male; D051379:Mice; D009393:Nephritis / Q000139:chemically induced / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D020556:Neutrophil Infiltration; D009504:Neutrophils / Q000378:metabolism*; D022641:Shiga Toxin 2 / Q000633:toxicity
D054360:Chemokine CXCL1; D054426:Chemokine CXCL2; D018925:Chemokines; D019743:Chemokines, CXC; C475895:Cxcl1 protein, mouse; C404915:Cxcl2 protein, mouse; D008070:Lipopolysaccharides; D022641:Shiga Toxin 2