Keratinocyte stem cell colonies can be identified by analyzing cell motion, an emergent stem cell property.

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Promyelocytic leukemia zinc-finger (PLZF) is a transcriptional repressor and tumor suppressor. PLZF is expressed in melanocytes but not in melanoma cells, and recovery of PLZF expression markedly suppresses melanoma cell growth. Several target genes regulated by PLZF have been identified, but the precise function of PLZF remains uncertain. Here, we searched for candidate target genes of PLZF by DNA microarray analysis. Pre-B-cell leukemia transcription factor 1 (Pbx1) was one of the prominently suppressed genes. Pbx1 was highly expressed in melanoma cells, and its expression was reduced by transduction with the PLZF gene. Moreover, the growth suppression mediated by PLZF was reversed by enforced expression of Pbx1. Knockdown of Pbx1 by specific small interfering RNAs suppressed melanoma cell growth. We also found that Pbx1 binds HoxB7. Reverse transcription-polymerase chain reaction analysis demonstrated that repression of Pbx1 by PLZF reduces the expression of HoxB7 target genes, including tumor-associated neoangiogenesis factors such as basic fibroblast growth factor, angiopoietin-2 and matrix metalloprotease 9. These findings suggest that deregulation of Pbx1 expression owing to loss of PLZF expression contributes to the progression and/or pathogenesis of melanoma.

Androgen-independent cell line DU145 cells lack PLZF gene expression, resulting in the upregulation of Pbx1 and HoxC8 expression. The Pbx1-HoxC8 heterocomplex may lead to androgen-independent growth in prostate cancer.

Background-Pemphigus foliaceus (PF) is an autoimmune blistering disease caused by autoantibodies (Abs) against desmoglein 1 (Dsg1). PF sera contain polyclonal Abs which are heterogeneous mixture of both pathogenic and non-pathogenic Abs, as shown by isolation of monoclonal Abs (mAbs).Objective-To investigate how pathogenic and non-pathogenic anti-Dsg1 Abs contribute to blister formation in PF.Methods-Using organ-cultured human skin, we compared the effect of a single pathogenic antiDsg1 IgG mAb, a single non-pathogenic anti-Dsg1 IgG mAb, and their mixture on blister formation as analyzed by histology, subcellular localization of IgG deposits and desmosomal proteins by confocal microscopy, and desmosomal structure by electron microscopy. In addition, we measured keratinocyte adhesion by an in vitro dissociation assay.Results-24 h after injection, a single pathogenic anti-Dsg1 IgG caused a subcorneal blister with IgG and Dsg1 localized linearly on the cell surface of keratinocytes. A single non-pathogenic antiDsg1 IgG bound linearly on the keratinocytes but did not induce blisters. A pathogenic and a nonpathogenic IgG mAb injected together caused an aberrant granular pattern of IgG and Dsg1 in the lower epidermis with blister formation in the superficial epidermis. Electron microscopy demonstrated that the mixture of mAbs shortened desmosomal lengths more than a single mAb in the basal and spinous layers. Furthermore, although Dsg1 clustering required both cross-linking of Dsg1 molecules by the non-pathogenic IgG plus a pathogenic antibody, the latter could be in the form of a monovalent single chain variable fragment, suggesting that loss of trans-interaction of ✩ This work was done at Tokyo, Japan. *Corresponding author at: Department of Dermatology, Toho University School of Medicine, 6-11-1, Omori-Nishi, Ota-ku, Tokyo 143-8541, Japan. ken.ishii@med.toho-u.ac.jp (K. Ishii). Conflict of interestThe authors have no conflict of interest to declare. HHS Public AccessAuthor manuscript J Dermatol Sci. Author manuscript; available in PMC 2017 July 14. Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptDsg1 is required for clustering. Finally, a p38MAPK inhibitor blocked Dsg1 clustering. When pathogenic strength was measured by the dissociation assay, a mixture of pathogenic and nonpathogenic IgG mAbs disrupted keratinocyte adhesion more than a single pathogenic mAb. This pathogenic effect was only partially suppressed by the p38MAPK inhibitor.Conclusion-These findings indicate that a polyclonal mixture of anti-Dsg1 IgG antibodies enhances pathogenic activity for blister formation associated with p38MAPK-dependent Dsg1 clustering and that not only pathogenic antibodies but also non-pathogenic antibodies coordinately contribute to blister formation in PF.

IL-22 induces STAT3 phosphorylation and mediates psoriasis-related gene expression.However, the signaling mechanism leading from pSTAT3 to the expression of these genes remains unclear. We focused on Bcl-3, which is induced by STAT3 activation and mediates gene expression. In cultured human epidermal keratinocytes, IL-22 increased Bcl-3, which was translocated to the nucleus with p50 via STAT3 activation. The increases in CXCL8, S100As and human β-defensin 2 mRNA expression caused by IL-22 were abolished by siRNA against Bcl-3. Although CCL20 expression was also augmented by IL-22, the knockdown of Bcl-3 increased its level. Moreover, the combination of IL-22 and IL-17A enhanced Bcl-3 production, IL-22-induced gene expression, and the expression of other psoriasis-related genes, including those encoding IL-17C, IL-19, and IL-36γ. The expression of these genes (except for CCL20) was also suppressed by the knockdown of Bcl-3. Bcl-3 overexpression induced CXCL8 and HBD2 expression but not S100As expression. We also compared Bcl-3 expression between psoriatic skin lesions and normal skin. Immunostaining revealed strong signals for Bcl-3 and p50 in the nucleus of epidermal keratinocytes from psoriatic skin. The IL-22-STAT3-Bcl-3 pathway may be important in the pathogenesis of psoriasis.Keywords: Bcl-3 r IL-22 r p50 r Psoriasis r STAT3 Additional supporting information may be found in the online version of this article at the publisher's web-site Introduction IL-22 mainly affects epithelial cells and is important for defense against environmental insults such as infection and injury [1][2][3]. When skin is injured or invaded by a pathogen, IL-22 is produced by skin homing cells or recruited cells and signals through the IL-22 receptor (IL-22R) expressed on epidermal keratinocytes, Correspondence: Dr. Mikiko Tohyama e-mail: tohm@m.ehime-u.ac.jp resulting in an increased epidermal thickness and enhanced mRNA expression of various compounds, including S100 calcium-binding protein (S100A) family proteins, β-defensins, cytokines, and chemokines [4][5][6]. This response enhances cutaneous defenses and causes inflammation. These defense responses are enhanced in psoriasis, a chronic inflammatory cutaneous disease in which the skin exhibits a robust structure composed of a thick horny epidermal layer with altered keratinocyte differentiation and overexpression of antimicrobial peptides, cytokines, and chemokines from keratinocytes. It is thought that IL-22 and IL-17A mediate gene expression in the inflammatory response of psoriasis [7,8].www.eji-journal.eu Eur. J. Immunol. 2018. 48: 168-179 Allergy and inflammation 169Several studies have revealed important roles for STAT3 activation in the pathogenesis of psoriasis [9,10], and STAT3 is the principal mediator of IL-22 signaling [11,12]. Therefore, studies of IL-22-STAT3 signaling may be significant for elucidating the pathomechanisms of psoriasis. IL-22-responsive genes include CCL2 and suppressor of cytokine signaling 3 (SOCS3), which are known to be involved downstream o...

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The skin microbiome influences skin pathophysiology. Palmoplantar pustulosis (PPP) is a chronic skin disease characterized by infectious‐like pustules on the palms and soles. These pustules are thought to be sterile because bacterial cultures obtained from the pustules are negative. However, culture methods are limited in their ability to identify all bacteria on the skin. We hypothesized that the “sterile” pustules of PPP do not lack bacteria, but rather contain a microbiome. To test this hypothesis, we identified bacteria in “sterile” pustules using non‐culture methods. We conducted Sanger and 16S rRNA sequencing using primers specific to the V1‐V2 region in PPP‐pustulovesicles (PVs) (n = 43) and pompholyx vesicle fluids (n = 15). Sanger sequencing identified some Staphylococcus, Propionibacterium, Streptococcus and Pyrinomonas species in PPP‐PVs but failed to identify any bacteria in most of the pompholyx vesicles. 16S rRNA sequencing of PPP‐PVs indicated the presence of a microbiome that included various phyla, including Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. At the genus level, smokers had higher levels of Staphylococcus in PPP‐PVs compared with non‐smokers. These results indicate that a microbiome exists in “sterile” pustules of PPP and that PPP smokers had higher levels of Staphylococcus in pustules. It is therefore necessary to reconsider the pathogenesis of PPP from the perspective of the microbiome.