Differential Regulation of Integrin α5 and ß4 in Normal and Psoriatic Epidermal Keratinocytes

Abstract Psoriasis is a chronic skin inflammation, characterized by impaired differentiation, hyperproliferation of keratinocytes involving pro-inflammatory factors interleukin (IL)-13/17A, tumor necrosis factor (TNF)-α, interferon (IFN)-γ. Among the integrin family, α5 is important for blood vessel formation, and ß4 for proliferation, differentiation of keratinocytes. To investigate the expression and regulation of integrin α5 and ß4 in psoriatic keratinocytes. Skin biopsies were obtained from 14 psoriatic patients and 12 normal volunteers. We compared the immunolocalization and regulation of α5 and ß4 between the psoriatic and normal ones, before and after incubation with MEK/ERK pathway inhibitor U0126 by immunohistochemistry and western blot separately. Immunohistochemistry showed psoriatic keratinocytes had higher α5 than normal ones. According to western blot, IL-17A and IL-13 increased normal keratinocytes' α5 and ß4 respectively, but psoriatic keratinocytes were the exact opposite. Incubated with U0126, normal keratinocytes' α5 was enhanced by the 5 cytokines ; while IL-13/17A, IFN-γ suppressed ß4. Psoriatic keratinocytes' α5 was increased by IL-13/17A, decreased by IFN-γ; but ß4 increased by IL-17A, IFN-γ. IL-13/17A, TNF-α, IFN-γ regulate α5 and ß4 through ERK pathway whether normal or psoriasis. The normal and psoriatic keratinocytes respond to the same cytokines differently

Ustekinumab treats psoriasis by suppressing RORC and T-box but its suppression of GATA restrains its efficacy

Psoriasis is a T-cell mediated disease that involves IL-23/Th17 and IL-12/Th1 axes. Ustekinumab, a fully human monoclonal antibody targeting the p40 subunit of both IL-12 and IL-23, has proven to be efficient and safe for treating patients with psoriasis. Yet, there have been no reports with human skin/blood samples that would elucidate the molecular mechanisms by which ustekinumab calms psoriasis skin lesions. To investigate the efficacy and molecular pathway (RORC, t-BOX and GATA) of ustekinumab in treating patients with psoriasis skin lesions. A total of 30 patients with psoriasis were randomized into placebo group and treatment group. PASI of each patient was calculated at 0, 12 and 24 weeks post-treatment. The mRNA levels of RORC, t-BOX and GATA in peripheral blood mononuclear cells separated from patients' whole blood were analyzed using qPCR. Decreased mRNA of RORC, t-BOX and GATA were observed after continuous injections, indicating that ustekinumab exerts its effect by interacting with these molecules; while no significant difference in foxp3 mRNA levels were found between placebo group and treatment group.