ABSTRACT
Psoriasis is a common chronic skin disease with a largely unknown pathogenesis. We demonstrate here that transgenic over-expression of interleukin (IL)-22 in mice resulted in neonatal mortality and psoriasis-like skin alterations including acanthosis and hypogranularity. This cutaneous phenotype may be caused by the direct influence of IL-22 on keratinocytes, since this cytokine did not affect skin fibroblasts, endothelial cells, melanocytes, or adipocytes. The comparison of cytokines with hypothesized roles in psoriasis pathogenesis determined that neither interferon (IFN)-gamma nor IL-17, but only IL-22 and, with lower potency, IL-20 caused psoriasis-like morphological changes in a three-dimensional human epidermis model. These changes were associated with inhibited keratinocyte terminal differentiation and with STAT3 upregulation. The IL-22 effect on differentiation-regulating genes was STAT3-dependent. In contrast to IL-22 and IL-20, IFN-gamma and IL-17 strongly induced T-cell and neutrophilic granulocyte-attracting chemokines, respectively. Tumor necrosis factor-alpha potently induced diverse chemokines and additionally enhanced the expression of IL-22 receptor pathway elements and amplified some IL-22 effects. This study suggests that different cytokines are players in the psoriasis pathogenesis although only the IL-10 family members IL-22 and IL-20 directly cause the characteristic epidermal alterations.
Subject(s)
Epidermis/drug effects , Interferon-gamma/pharmacology , Interleukin-17/pharmacology , Interleukins/pharmacology , Animals , Blotting, Western , Cell Differentiation/drug effects , Cells, Cultured , Chemokines/genetics , Chemokines/metabolism , Drug Synergism , Enzyme-Linked Immunosorbent Assay , Epidermis/metabolism , Epidermis/pathology , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/pathology , Humans , Immunohistochemistry , Interleukins/genetics , Interleukins/metabolism , Keratinocytes/drug effects , Keratinocytes/metabolism , Keratinocytes/pathology , Mice , Mice, Inbred Strains , Mice, Transgenic , Psoriasis/genetics , Psoriasis/metabolism , Psoriasis/pathology , RNA Interference , Reverse Transcriptase Polymerase Chain Reaction , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Interleukin-22ABSTRACT
Transcriptional repression and activation by nuclear receptors (NRs) are brought about by coregulator complexes. These complexes modify the chromatin environment of target genes and affect the activity of the basal transcription machinery. We have previously implicated the yeast ADA3 protein in transcriptional activation by estrogen and retinoid X receptors in yeast and mammalian cells. Here we report the cloning of the mouse homolog of ADA3 and its characterization with respect to the estrogen receptor alpha (ERalpha) function. Mouse mADA3 is 23% identical and 47% similar to yeast yADA3, and mADA3 in contrast to yADA3 does not interact with NRs directly even though it contains two LxxLL NR boxes. However, the ADA3-containing TBP-free-TAF-containing complex (TFTC) can interact with ERalpha in a ligand-independent manner, indicating that other subunits of the complex are sufficient to mediate interaction with NRs.
Subject(s)
Receptors, Estrogen/metabolism , Saccharomyces cerevisiae Proteins , Transcription Factors/metabolism , Animals , COS Cells , Cell Line , Estrogen Receptor alpha , Expressed Sequence Tags , Fungal Proteins/chemistry , Fungal Proteins/genetics , Humans , Macromolecular Substances , Mice , Molecular Sequence Data , Precipitin Tests , Protein Binding , Receptors, Estrogen/genetics , Sequence Homology , Transcription Factors/chemistry , Transcription Factors/genetics , Two-Hybrid System TechniquesABSTRACT
The RNA polymerase II transcription factor TFIID, composed of the TATA-binding protein (TBP) and TBP-associated factors (TAF(II)s), nucleates preinitiation complex formation at protein-coding gene promoters. SAGA, a second TAF(II)-containing multiprotein complex, is involved in transcription regulation in Saccharomyces cerevisiae. One of the essential protein components common to SAGA and TFIID is yTAF(II)25. We define a minimal evolutionarily conserved 91-amino-acid region of TAF(II)25 containing a histone fold domain that is necessary and sufficient for growth in vivo. Different temperature-sensitive mutations of yTAF(II)25 or chimeras with the human homologue TAF(II)30 arrested cell growth at either the G(1) or G(2)/M cell cycle phase and displayed distinct phenotypic changes and gene expression patterns. Immunoprecipitation studies revealed that TAF(II)25 mutation-dependent gene expression and phenotypic changes correlated at least partially with the integrity of SAGA and TFIID. Genome-wide expression analysis revealed that the five TAF(II)25 temperature-sensitive mutant alleles individually affect the expression of between 18 and 33% of genes, whereas taken together they affect 64% of all class II genes. Thus, different yTAF(II)25 mutations induce distinct phenotypes and affect the regulation of different subsets of genes, demonstrating that no individual TAF(II) mutant allele reflects the full range of its normal functions.
