calpain and Dermatitis--Atopic

Filaggrin is central to the pathogenesis of atopic dermatitis (AD). The cheeks are a common initiation site of infantile AD. Regional and temporal expression of levels of filaggrin degradation products [natural moisturizing factors (NMFs)], activities of filaggrin-processing enzymes [bleomycin hydrolase (BH) and calpain-1 (C-1)] and plasmin, and corneocyte envelope (CE) maturity in early life are largely unknown.. We conducted a cross-sectional, observational study investigating regional and age-dependent variations in NMF levels, activity of proteases and CE maturity in stratum corneum (SC) from infants to determine whether these factors could explain the observed predilection sites for AD in early life.. We measured NMF using a tape-stripping method at seven sites in the SC of 129 children (aged < 12 months to 72 months) and in three sites in 56 neonates and infants (< 48 h to 3 months). In 37 of these neonates and infants, corneocyte size, maturity, BH, C-1 and plasmin activities were determined.. NMF levels are low at birth and increase with age. Cheek SC, compared with elbow flexure and nasal tip, has the lowest NMF in the first year of life and is the slowest to reach stable levels. Cheek corneocytes remain immature. Plasmin, BH and C-1 activities are all elevated by 1 month of age in exposed cheek skin, but not in elbow skin.. Regional and temporal differences in NMF levels, CE maturity and protease activities may explain the predilection for AD to affect the cheeks initially and are supportive of this site as key for allergen priming in early childhood. These observations will help design early intervention and treatment strategies for AD.

Topics: Age Factors; Calpain; Cheek; Child, Preschool; Cross-Sectional Studies; Cysteine Endopeptidases; Dermatitis, Atopic; Elbow; Female; Fibrinolysin; Filaggrin Proteins; Humans; Infant; Infant, Newborn; Intermediate Filament Proteins; Male; Mutation; Skin

Filaggrin (FLG) and its metabolites are essential for skin barrier function and hydration of the stratum corneum. Alteration of the FLG metabolism could be the basis for an abnormal skin barrier in allergic dogs.. To investigate the expression and distribution of calpain-1, caspase-14, furin and matriptase, four enzymes involved in FLG metabolism, in the skin of atopic and healthy beagles.. Skin biopsies were collected from four healthy and four atopic beagles before and after allergen exposure. The dogs were challenged for three consecutive days to mimic an acute exposure, or once weekly to mimic a chronic exposure to allergens. Skin biopsies were taken on days 0 (nonlesional), 3 and 10 in the "acute" model and on days 0 (nonlesional), 14 and 28 in the "chronic" model. Four healthy dogs were used as controls. Indirect immunofluorescence was used to analyse the distribution and the expression of FLG enzymes in a semi-quantitative manner. Five consecutive pictures/section were taken and the intensity analysed tracing the epidermis and using ImageJ on the traced areas. The enzymes' expression was compared between healthy and atopic nonlesional skin (Day 0) and over time in each group.. All enzymes were expressed in all layers of the epidermis. A significantly higher expression of calpain-1 (P = 0.028), caspase 14 (P = 0.028) and matriptase (P = 0.028) was evident in atopic compared to control dogs on Day 0. No differences over time were seen for any enzyme analysed.. This preliminary study suggests an abnormal catabolism of FLG in canine atopic skin.

Topics: Animals; Calpain; Case-Control Studies; Caspase 14; Dermatitis, Atopic; Disease Models, Animal; Dog Diseases; Dogs; Female; Filaggrin Proteins; Furin; Intermediate Filament Proteins; Male; Pilot Projects; Serine Endopeptidases; Skin

Topics: Adult; Calpain; Caspase 14; Codon, Nonsense; Cysteine Endopeptidases; Dermatitis, Atopic; Down-Regulation; Female; Filaggrin Proteins; Humans; Intermediate Filament Proteins; Male; Skin

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

Changes in the levels of cytokines in the circulating blood and skin have been reported in patients with atopic dermatitis (AD). We determined IFN-gamma, IL-2, IL-4, IL-5 and IL-10 in both the serum and plasma of 45 AD patients and 20 healthy donors. Since differences in the levels of these cytokines between serum and plasma were found, the roles of Ca2+ and proteolytic enzymes were examined. Levels of IL-2 and IL-10 were measured in citrated plasma to which various amounts of CaCl2, protease inhibitors, and proteases had been added. All cytokine determinations were carried out using a standard ELISA. The plasma levels of IFN-gamma, IL-2, and IL-5 were significantly elevated, but the serum levels of these cytokines were not significantly changed. The levels of IL-2 in the plasma of the AD patients averaged 4.25-fold higher than in the serum of the AD patients, and 2.5-fold higher than in the plasma of healthy controls (P < 0.001). CaCl2 produced a dose-dependent decrease in IL-2 and IL-10 in citrated plasma. The protease inhibitors PMSF, aprotinin and leupeptin produced a dose-dependent increase in measurable levels of IL-2 and IL-10 in plasma. A decrease in IL-2 levels was also seen in CaCl2-supplemented serum-free medium, and this was accentuated by the addition of the proteases thrombin, trypsin, chymotrypsin and elastase. These findings suggest that although significant changes in cytokine levels have been reported not to occur in circulating blood but have been reported to occur in the skin of AD patients both in vivo and in vitro, cytokines can indeed also be found to be elevated in circulating blood when assessed carefully by statistically valid methods. Further, it is suggested that during the preparation of serum, some circulating cytokines are degraded by calcium-dependent proteases, and that Ca2+ itself can also affect the measurement of cytokines. The measurement of circulating cytokines needs to be carefully reassessed.

Topics: Adolescent; Adult; Calcium Chloride; Calpain; Culture Media, Serum-Free; Cytokines; Dermatitis, Atopic; Dose-Response Relationship, Drug; Female; Humans; Interferon-gamma; Interleukins; Male; Middle Aged; Plasma; Protease Inhibitors; Reference Values