Imiquimod enhances Th1 and Th17 cell responses by inducing IL-12 and IL-6 production in dendritic cells via the NF-κB pathway

This study investigates how imiquimod (IMQ) influences the activation and maturation of dendritic cells (DCs) and their subsequent effects on T helper (Th) cell polarization, contributing to the understanding of immunopharmacological mechanisms in psoriasis. The dataset includes experimental data from in vitro assays (FACS, RT-PCR, ELISA, IF assay) where bone marrow-derived DCs were treated with IMQ to induce maturation and cytokine production. Additionally, co-culture experiments were performed with CD4 T cells isolated from OT-II mice to assess the functional effects of IMQ-activated DCs on T cell polarization.

Sample Collection: Bone marrow-derived DCs were isolated from mice and treated with various doses (0.1, 0.5, 1, and 2 µg/ml) of IMQ in a dose-dependent manner. Naive CD4 T cells were isolated from OT-II mice.
Measurement Techniques: The activation and maturation markers of DCs were assessed using flow cytometry (FACS). Data were further analyzed using FlowJo software to quantify the expression of maturation markers (CD40, CD80, CD86, and MHC class II). Pro-inflammatory cytokine levels (IL-12, IL-6, TNF-α, and IL-1β) were measured using RT-PCR and ELISA. The activation of the NF-κB pathway was confirmed through immunofluorescence (IF) assays. Inhibitors of NF-κB signaling (CAPE and BAY) were applied to evaluate their effects on IMQ-induced DC maturation and activation, confirming a reduction in DC activation through FACS analysis. Additionally, co-culture experiments with IMQ-treated DCs and OT-II mouse-derived CD4 T cells were conducted to confirm naive CD4 T cell polarization into Th1, Th17, and potentially Th9, which was also analyzed using FACS. To determine whether the secretion of IL-12 and IL-6 from IMQ-stimulated DCs is associated with increased Th1 and Th17 cell populations, neutralizing anti-IL-12 and anti-IL-6 monoclonal antibodies were added to the co-cultures.

These findings reveal that IMQ enhances Th1 and Th17 cell responses through the activation of DCs and the production of IL-12 and IL-6 via the NF-κB pathway. This study contributes to our understanding of the immunopharmacological mechanisms associated with imiquimod-induced psoriasis, suggesting potential therapeutic targets for psoriasis intervention.