calpain and Psoriasis

Psoriatic keratinocytes express exaggerated levels of inflammatory cytokines, and show aberrant hyperproliferation and terminal differentiation in the pathogenesis of psoriasis. The antimicrobial protein hS100A7 (psoriasin) has been found highly expressed in psoriatic skin, but the mechanism and physiological function remain largely unknown. We observed that hS100A7 induces mature interleukin 1α (17kDa) expression in normal human epidermal keratinocytes, which is dependent on RAGE-p38 MAPK and calpain-1 as the inhibitors or knockdown of them completely decreased the expression of mature interleukin1α. Then, we proved mS100a7a15, mature IL-1α and calpain-1 were highly expressed in imquimod-induced psoriasis model and mouse IL-17a-neutralizing antibody treatment attenuated mS100a7a15 expression. At last, PD 151746 (calpain-1 inhibitor) treatment decreased epidermal thickness in imquimod-induced psoriasis model. Taken together, our results suggest that mature IL-1α induced by hS100A7 is via RAGE-p38 MAPK and calpain-1 pathway in keratinocyte and this mechanism may play an important role during psoriasis.

Topics: Acrylates; Animals; Calpain; Cell Line; Disease Models, Animal; Gene Expression; Humans; Hyperplasia; Interleukin-1alpha; Keratinocytes; Mice; p38 Mitogen-Activated Protein Kinases; Proteolysis; Psoriasis; Receptor for Advanced Glycation End Products; S100 Calcium Binding Protein A7; S100 Proteins

IL-33, a member of the IL-1 family, is implicated in type 2 T helper cell immune reactions and acts as an "alarmin" to induce activation of dendritic cells in response to external stimuli. We investigated the effect of inflammatory cytokines on IL-33 expression in normal human epidermal keratinocytes. IFN-γ dose- and time-dependently induced IL-33 expression in protein and mRNA; this was dependent on extracellular signal-regulated kinase, p38, EGFR, and JAK phosphorylation. Combined IFN-γ and tumor necrosis factor (TNF)-α treatment induced expression of a 20-kDa band corresponding to mature IL-33, which was abolished by the addition of a calpain inhibitor. The addition of the inhibitor to IFN-γ and TNF-α-stimulated cells also induced strong expression of a 25-kDa band. Small interference (si) RNA for IL-33 abolished expression of the smaller bands and the 30-kDa IL-33 band, suggesting that these IL-33 forms were IL-33 transcription products. Recombinant IL-33 added in the medium induced IL-8 production, and RNA knockdown by siRNA enhanced IL-8 expression, suggesting its dual role as a cytokine and a nuclear factor. These results indicate that IL-33 has a role in inflammatory skin diseases, in which IFN-γ and TNF-α are present in high levels.

Topics: Calpain; Cells, Cultured; Dermatitis, Atopic; Epidermal Cells; Epidermis; Foreskin; Gene Expression; Humans; Infant, Newborn; Interferon-gamma; Interleukin-33; Interleukin-8; Interleukins; Keratinocytes; Lichen Planus; Male; MAP Kinase Signaling System; Psoriasis; RNA Interference; Skin Diseases; Tumor Necrosis Factor-alpha

Psoriasis is believed to be a T cell-mediated autoimmune disease, but also exhibits autoantibody production. Calpastatin is an endogenous inhibitor of calpain, a ubiquitous protease that regulates inflammatory processes. Anti-calpastatin autoantibody was first identified as an autoantibody specific to rheumatoid arthritis, but has been also detected in other autoimmune diseases. In this study, we examined the presence and levels of anti-calpastatin antibody in 77 psoriasis patients by enzyme-linked immunosorbent assay. Compared with normal controls, psoriasis patients exhibited significantly elevated IgG anti-calpastatin antibody levels that were similar to those found in rheumatoid arthritis patients. Remarkably, IgG anti-calpastatin autoantibody in sera from psoriasis patients inhibited calpastatin activity. Calpain II expression was up-regulated in psoriasis skin lesions compared with normal skin while calpastatin expression was normal. The results of this study reveal the presence of anti-calpastatin autoantibody in psoriasis.

Topics: Adult; Antibodies, Monoclonal; Autoantibodies; Calcium-Binding Proteins; Calpain; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoglobulin G; Male; Middle Aged; Psoriasis; Skin

The biochemical properties and immunohistochemical localization of calpain, a Ca++-dependent, intracellular, nonlysosomal cysteine proteinase was examined in human skin. Human epidermal calpain I was fractionated on a DEAE-cellulose column and was found to be half-maximally activated at 3.5 microM free Ca++ and fully activated at 10 microM Ca++ as measured by casein hydrolysis. Immunoelectrophoretic blotting of calpain revealed only a single band of Mr 83,000, when the blot was made with affinity-purified anti-calpain I heavy subunit IgG. Immunohistochemical staining of normal human epidermis showed that calpain I was localized in the cytoplasm of keratinocytes in the mid to upper epidermis but not in the basal cells. In untreated psoriatic epidermis, the deposition of this proteinase was visualized weakly just beneath the stratum corneum. However, remarkable staining was observed after photochemotherapy of topical psoralen plus long-wave UV irradiation. Whether the photochemotherapy induced a quantitative increase in the amount of calpain or merely made calpain more stainable by altering the membrane remains unknown.

Topics: Antibody Specificity; Calpain; Electrophoresis, Polyacrylamide Gel; Epidermis; Humans; Photochemotherapy; Psoriasis; Sodium Dodecyl Sulfate; Staining and Labeling