Increased Dnmt1 Expression And Activity in Uroepithelial Cells Following Uropathogenig E.Coli Infection

Purpose

Urinary tract infection (UTI) affects millions of children and adults worldwide. Uropathogenic E.coli (UPEC) can form internal quiescent reservoirs (IQR) inside the uroepitheilal cells (UEC). We propose that IQR of UPEC incite epigenetic changes, specifically DNA methylation, in the UEC genome, which may alter host susceptibility to recurrent UTI. Methylation of DNA by DNA methyl transferase 1 (Dnmt-1) occurs in the promotor region, which is associated with loss of expression of genes such as p16, a cell cycle regulator.

Material and Methods

In this study, we investigated whether acute infection at low multiplicities of infection (MOI) with FimH [+] E.coli (UT-189) can induce methylation changes by DNMT1 enzyme activaty.

Results

Real-Time PCR revealed a 6-fold increase in DNMT-1 mRNA expression in UT-189 infected UEC compared to non-infected UEC. This increase at the mRNA level correlated with a 170-fold increase in DNMT activity in infected vs. non-infected UEC. Real-time PCR for p16, showed a 3-fold decrease in the mRNA level in infected UEC compared to non-infected cells.

Conclusions

The above data suggest that internalization of FimH [+] E.coli can induce the DNA methylation machinery, possibly downregulating expression by methylation of CpG islands of p16 gene in the UEC DNA. Methylation Specific PCR (MSP) will be employed to determine if the decreased expression of p16, and possibly other candidate genes, is due to downregulation by promotor hypermethylation. Identification of epigenetic alteration in UEC exposed to E.coli may provide a new paradigm for UTI pathogenesis and preemptive diagnosis.

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