Microarray expression data from P50 mouse full thickness back skin of C57BL/6 mice - various durations of IMQ treatment and timepoints.

Imiquimod (IMQ) is a topical therapeutic immune activator that causes psoriasiform inflammation in mice. To determine if IMQ-induced inflammation and gene expression changes depended on the time of day in which treatment is administered, we performed gene expression profiling of dorsal mouse back skin by microarray after different durations of topical 1% IMQ treatment (control = no treatment, 6 hr, 24 hr, and 5 days of IMQ treatment) at different times of day (ZT01, ZT07, ZT09 = day-time treatment; ZT13 and ZT19 = night-time treatment). We also performed a time course after IMQ treatment by collecting mouse back skin after 0 (no treatment), 1, 2, 4, 6, and 24 hours post-treatment. Lastly, we determined gene expression changes in response to IMQ in mice deleted for the core circadian clock gene, Bmal1, after 0 (no treatment) and 24 hours post-1% IMQ compared to Wt (both treated and collected during the daytime at ZT09). The results of this study are important as they show that IMQ-induced activation of interferon sensitive genes are diurnal in Wt mice after 6 hours and 24 hours but not after 5 consecutive treatments. Furthermore, we find that interferon sensitive genes are induced more robustly in the skin of Bmal1 KO mice after 24 hr IMQ compared to Wt mice. These results are important for further understanding how the circadian clock regulates immune activation in response to the theraputic agent IMQ.

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Greenberg EN, Marshall ME, Jin S, Venkatesh S, Dragan M, Tsoi LC, Gudjonsson JE, Nie Q, Takahashi JS, Andersen B