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ROLE OF EZH2 IN INFECTION-INDUCED URO-EPITHELIAL CELL PROLIFERATION
Darius BAGLI
1
, Karen AITKEN
2
, Kenneth TING
2
and Alaleh SAMIEI
2
1) Sickkids Hospital, Division of Urology, Department of Surgery, Toronto, CANADA - 2) Research Institute, Sickkids
Hospital, Developmental and Stem Cell Biology, Toronto, CANADA
PURPOSE
Upon Urinary Tract Infection (UTI), UPEC infected superficial umbrella cells undergo apoptosis and exfoliation. In
regenerating endoderm such as uro-epithelium, signal transduction cascades alongside epigenetic events underlie
proliferation and differentiation events. Understanding that UPEC can alter epigenetic machineries upon infection as
shown from in previous research (Lab Invest, 2011), we investigated if UPEC induced proliferation is dependent upon
another epigenetic events, Histone lysine27 triemethylation (H3K27me3).
MATERIAL AND METHODS
To establish an association between proliferation and EZH2, immunofluorescence was used to quantify the expression of
EZH2 and PCNA in UPEC inoculated HTB9 cells within 3 days (p.i.). H3K27trimethylation was also examined grossly by
immunostaining. To establish a causation relationship between cell proliferation and EZH2, cell viability assay was
performed to quantify the metabolic activity of UPEC inoculated HTB9 cells treated with UNC1999, a catalytic inhibitor of
EZH2, 48 hours p.i. The effect of GSKJ4, a catalytic inhibitor of JMJD3, involved in de-methylation at H3K27, was also
examined.
RESULTS
UPEC inoculation of HTB9 cells significantly increases H3K27me3 levels 48 hours post-inoculation (p.i.). In HTB9 cells,
UPEC induced a significantly higher expression (p< 10-15) of EZH2 and PCNA than control within 3 days of post-
inoculation. These expression levels correlated with each other (R2=0.74, p<0.05). A significant reduction of viability is
also found in UPEC inoculated cells treated with UNC1999, vs. vehicle. GSKJ4 further enhanced PCNA expression in FIM
H+ inoculated cells, confirming the positive role that EZH2 plays in UPEC-induced proliferation.
CONCLUSIONS
The results from our study have implications in enhancing progeny cells’ defense against chronic UTI via manipulating
the epigenetic aspect of host cells’ response to infection. It also provides potential epigenetic markers that help to
evaluate the risk of UTI reinfection in clinical settings.