The effect of nitric oxide on adherence of P-fimbriated uropathogenic Escherichia coli to human renal epithelial cells.
OBJECTIVE
To examine the effect of nitric oxide (NO), an endogenous component of the host defence in urinary tract infection, on the adherence of P-fimbriated uropathogenic Escherichia coli (UPEC) to human renal epithelial cells.


METHODS
Two wild-type UPEC strains (AD110 and IA2) and the P-fimbriated recombinant strain HB101pPIL-75 were used. Bacteria were allowed to adhere to the human renal epithelial cell line A498 and attachment was evaluated in the absence or presence of the NO donor DETA/NONOate (1 mm). Total RNA was extracted from NO-exposed bacteria in static urine cultures, followed by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of the papG gene that encodes the P-fimbriae adhesin PapG.


RESULTS
Bacterial adherence to A498 cells was fimbriae-dependent and the ability to agglutinate human P(1) positive erythrocytes confirmed that the used strains were P-fimbriated. UPEC strains AD110 and IA2 attached by a mean of 8 bacteria/cell and 20 bacteria/cell, respectively. In the presence of DETA/NONOate, the attachment of AD110 and IA2 to A498 cells was significantly reduced by a mean (sem) of 34 (3.9)% and 45 (14)%, respectively. The expression of papG was decreased after DETA/NONOate exposure as shown by semiquantitative RT-PCR.


CONCLUSIONS
NO disrupted functional adhesion of P-fimbriated UPEC to kidney epithelial cells, suggesting that NO-production from epithelial cells in the urinary tract may limit bacterial colonization at the mucosal surface. The reduced adherence may involve transcriptional effects of NO on papG expression, but further studies are needed to establish the underlying mechanisms.
School of Pure and Applied Natural Sciences, University of Kalmar, Kalmar, Sweden.
Lovisa
L
Svensson
Susanne
S
Säve
Katarina
K
Persson
D001422:Bacterial Adhesion / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D004927:Escherichia coli Infections / Q000382:microbiology*; D010861:Fimbriae, Bacterial / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000382:microbiology; D009569:Nitric Oxide / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014552:Urinary Tract Infections / Q000382:microbiology*; D056689:Uropathogenic Escherichia coli / Q000187:drug effects*
D009569:Nitric Oxide