The Effects of Resiquimod Treatment on the Asthma Transcriptome

Resiquimod is a nucleoside analog belonging to the imidazoquinoline family of compounds which is known to signal through Toll-like receptor 7. Resiquimod treatment has been demonstrated to inhibit the development of allergen induced asthma in experimental models. Despite this demonstrated effectiveness, little is known about the molecular events responsible for this effect. The aim of the present study was to elucidate the molecular processes which were altered following resiquimod treatment and antigen challenge in a mouse model of allergic asthma. Employing microarray analysis, we have characterized the asthmatic transcriptome of the murine lung and determined that it includes genes involved in: the control of cell cycle progression, airway remodelling, the complement and coagulation cascades, and chemokine signalling. We have demonstrated that systemic resiquimod administration resulted in the recruitment of NK cells to the lungs of the mice, although no causal relationship between NK cell recruitment and treatment efficacy was found. Furthermore, results of our studies demonstrated that resiquimod treatment resulted in the normalization of the expression of genes involved with airway remodelling and chemokine signalling, and in the modulation of the expression of genes including cytokines and chemokines, adhesion molecules, and B-cell related genes, involved in several aspects of immune function and antigen presentation. Overall, our findings identified several genes, important in the development of asthma pathology, that were normalized following resiquimod treatment thus improving our understanding of the molecular consequences of resiquimod treatment in the lung milieu.

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Camateros P, Kanagaratham C, Henri J, Sladek R, Hudson TJ, Radzioch D