Suppression of IL-12/IL-23 p40 subunit in the skin and blood of psoriasis patients by Tofacitinib is dependent on active interferon-γ signaling in dendritic cells: Implications for the treatment of psoriasis and interferon-driven diseases

Abstract

Interleukin (IL)-12 and IL-23 are pro-inflammatory cytokines produced by dendritic cells (DCs) and associated with Psoriasis (Pso) and Psoriatic Arthritis (PsA) pathogenesis. Tofacitinib, a Janus kinase inhibitor, effectively suppresses inflammatory cascades downstream the IL-12/IL-23 axis in Pso and PsA patients. Here, we investigated whether Tofacitinib directly regulates IL-12/IL-23 production in DCs, and how this regulation reflects responses to Tofacitinib in Pso patients. We treated monocyte-derived dendritic cells and myeloid dendritic cells with Tofacitinib and stimulated cells with either lipopolysaccharide (LPS) or a combination of LPS and IFN-γ. We assessed gene expression by qPCR, obtained skin microarray and blood Olink data and clinical parameters of Pso patients treated with Tofacitinib from public data sets. Our results indicate that in DCs co-stimulated with LPS and IFN-γ, but not with LPS alone, Tofacitinib leads to the decreased expression of IL-23/IL-12 shared subunit IL12B (p40). In Tofacitinib-treated Pso patients, IL-12 expression and psoriasis area and severity index (PASI) are significantly reduced in patients with higher IFN-γ at baseline. These findings demonstrate for the first time that Tofacitinib suppresses IL-23/IL-12 shared subunit IL12B in DCs upon active IFN-γ signaling, and that Pso patients with higher IFN-γ baseline levels display improved clinical response after Tofacitinib treatment.

Keywords: Janus Kinase Inhibitors; dendritic cells; interferon; p40; psoriasis.

FIGURE 1

Cytokine gene expression in LPS‐stimulated DCs treated with Tofacitinib. (A‐B) Gene expression of IL12B, IL12A and IL23A subunits (A) and TNF (B) in mDCs (n = 10). (C‐E) IL12B, IL12A and IL23A subunits (C), TNF (D) and CXCL10 (E) in moDCs (n = 12). mDCs and moDCs were pre‐treated or not with Tofacitinib for 30 min and stimulated with LPS for 4 h. Gene expression was measured by real‐time qPCR and represented as relative expression (2^−∆CT). Lines connect individual donors. Significance was determined by Friedman's test followed by Dunn's multiple comparisons test

FIGURE 2

IL12B gene expression is suppressed by Tofacitinib in the presence of IFN‐γ in LPS‐stimulated mDCs and moDCs. (A, B) Gene expression of IL12B, IL12A, IL23A (A) and TNF and CXCL10 (B) in mDCs (n = 12). (C‐D) Gene expression of IL12B, IL12A and IL23A (C) and TNF and CXCL10 (D) in moDCs (n = 13). mDCs and moDCs were pre‐treated or not with Tofacitinib for 30 min and stimulated with a combination of LPS and IFN‐γ for 4 h. Gene expression was measured by real‐time qPCR and represented as relative expression (2^−∆CT). Lines connect individual donors. Significance was determined by Friedman's test followed by Dunn's multiple comparisons test

FIGURE 3

Patients with higher basal IFN‐γ display higher basal IL‐12 levels and have a significant reduction in IL‐12 levels when treated with Tofacitinib (A) Normalized Protein eXpression (NPX) of IL‐12 protein levels in the blood of Pso patients before and after 4 weeks treatment with either Tofacitinib (n = 134) or Etanercept (n = 125). (B) NPX of baseline blood IFN‐γ protein levels for patients treated with Tofacitinib or Etanercept. Treatment groups were divided by the mean IFN‐γ expression to define IFN‐γ high or low patients. (C) NPX of baseline IL‐12 protein levels per treatment group for IFN‐γ high or low patients. (D) Delta decrease of IL‐12 (ΔIL‐12) after 4 weeks of treatment with either Tofacitinib or Etanercept for IFN‐γ high or low patients. Significance was determined by the Kruskal‐Wallis test followed by Dunn's multiple comparisons test. Series matrix data derived from public database GSE136435. (E) Gene expression of IL12B after 0, 4 and 12 weeks of Tofacitinib treatment in whole lesional psoriatic skin (n = 9) compared to paired non‐lesional skin. (F) Delta decrease of IL12B mRNA in relation to baseline IFN‐γ mRNA in lesional psoriatic skin after 12 weeks of Tofacitinib treatment (n = 9). Data from patient 10021001 was only available until 4 weeks of treatment. Series matrix data derived from public database GSE69967