A. GATA3 protein is present in the nuclei of the suprabasal layers of the epidermis in normal skin. In non-lesional psoriatic skin GATA3 is expressed in all epidermal layers whereas in lesional skin sporadic GATA3 expression is observed. The borders of the epidermis are depicted. Scale bar: 100 µm. B. Expression of GATA3 mRNA was almost seven-fold lower in lesional skin (PP) compared to non-lesional skin (PN). Epidermal GATA3 mRNA expression was determined by RT-PCR using ABL1 as a housekeeping control gene. In each patient, GATA3 expression in lesional skin is calculated relative to the expression in non-lesional skin. Bars represent mean +/− SEM (n = 5 patients). C. GATA3 mRNA expression in imiquimod-induced psoriasiform dermatitis in mice is lower than in control back skin of BALB/c mice. Bars indicate the mean +/− SEM (n = 3 mice per group).

A. GATA3 expression is upregulated during the course of NB-UVB phototherapy in patients with psoriasis. 3 mm biopsies were taken from lesional (PP) and non-lesional skin of patients with psoriasis before, during and after NB-UVB phototherapy. Epidermal GATA3 mRNA expression was determined with RT-PCR using ABL1 as a housekeeping control gene. Bars represent mean +/− SEM (n = 5 patients). The interrupted line shows change in the PASI score, relative to the baseline score. B. Psoriasiform dermatitis was induced in BALB/c mice by daily treatment with IMQ cream (or control cream) on the shaved back skin, and irradiated or sham-irradiated every other day with NB-UVB, starting on the first day of imiquimod treatment. Erythema, scaling, and thickness of the back skin were scored daily on a scale from 0 to 4. The cumulative score (erythema plus scaling plus thickness) is shown. Symbols indicate mean score +/− SEM of three mice per group. C. X-gal staining (blue) of GATA3LacZ skin biopsies from mice with psoriasiform dermatitis with or without NB-UVB treatment. D. BrdU incorporation in keratinocytes in the back skin was detected by immunohistochemistry. The bars represent the mean number of BrdU positive cells +/− SD. E. Biopsies from psoriasiform dermatitis on the back skin of the mice were stained for Keratin 1/10. Scale bars on panels C, D and E: 100 µm.

A. Six psoriatic patients underwent repeated tape stripping to induce skin activation and regeneration. Directly before and 5 h after tape stripping biopsies were taken and epidermal GATA3 expression was determined using RT-PCR, relative to ABL1 as a housekeeping control gene. Relative expression values of individual patients are shown. B. GATA3 expression is downregulated in the healing wound of mouse skin. X-gal staining (blue) of wounded skin of a GATA3LacZ mouse shows downregulation of the LacZ transgene under control of GATA3 in the highly proliferative zone of the healing wound. Arrows indicate X-Gal positive cells; the border between regenerating and adjacent normal skin is marked. Scale bar: 200 µm.

Primary human epidermal keratinocytes were cultured on chamber slides. When cells were approximately 75% confluent, 1.2 mM CaCl₂ (B, D) and/or 3 ng/ml TGF-β1 (C, D) were added to the culture medium. After 24 h cells were fixed and immunofluorescent staining for GATA3 protein (pink) was performed. E. GATA3 positive cell nuclei were counted and are shown as a percentage of the total number of cell nuclei. Scale bar: 20 µm.

Three mm biopsies from normal human skin were cultured in the presence of proinflammatory cytokines for 24 h. The epidermis was separated from the dermis and GATA3 expression was measured by RT-PCR in epidermal RNA, using ABL1 as a housekeeping control gene. Bars represent mean +/− SEM (n = 4 (IFN-α, IL-22), n = 6 (IL-4) or n = 8 (IFN-γ) healthy donors).