DERMAL STEM CELLS & TISSUE REGENERATION Keratinocyte Microvesicles Regulate the Expression of Multiple Genes in Dermal Fibroblasts Researchers investigated whether microvesicle-like structures are present in human wounds and whether they affect wound healing-associated gene expression in dermal fibroblasts. [J Invest Dermatol] Abstract Fate of Prominin-1 Expressing Dermal Papilla Cells During Homeostasis, Wound Healing and Wnt Activation By examining endogenous Prominin-1/CD133 (Prom1) expression and expression of LacZ in the skin of Prom1CreERLacZ mice, investigators confirmed that Prom1 is expressed in the dermal papilla of all developing hair follicles and also by postnatal anagen follicles. [J Invest Dermatol] Abstract | Full Article Vitamin D Induces Cyclooxygenase 2 Dependent Prostaglandin E2 Synthesis in HaCaT Keratinocytes Treatment of human immortalized HaCaT keratinocytes with calcitriol increased prostaglandin E2 production due to increased mRNA and protein expression of COX-2, but not to increase of COX-1 or release of arachidonic acid. [J Cell Physiol] Abstract Antibiotics in Cell Culture: Friend or Foe? Suppression of Keratinocyte Growth and Differentiation in Monolayer Cultures and 3D Skin Models The authors investigated the effect of the most commonly used antibiotics; gentamycin and the combination of penicillin and streptomycin on keratinocyte growth and differentiation. [Exp Dermatol] Abstract Vitamin D and Calcium Regulation of Epidermal Wound Healing Mice lacking the vitamin D receptor when placed on a low calcium diet had delayed wound healing. This was associated with reduced β-catenin transcriptional activity and proliferation in the cells at the leading edge of wound closure. [J Steroid Biochem Mol Biol] Abstract miR-526b Targets 3′ UTR of MMP1 mRNA Using reporter constructs containing the 3′ untranslated region of matrix metalloproteinases 1 (MMP1) and its mutant form, scientists showed that the region from 377–383 in the 3′ UTR of MMP1 is critical for targeting by miR-526b. In addition, the expression pattern of miR-526b and MMP1 mRNA showed reverse relation between adult dermal and neonatal fibroblasts. [Exp Mol Med] Full Article SKIN CANCERS & DISORDERS Circadian Gene Clock Regulates Psoriasis-Like Skin Inflammation in Mice The authors found that Clock mutation ameliorated imiquimod (IMQ)-induced dermatitis whereas Period2 mutation exaggerated IMQ-induced dermatitis when compared with wild-type mice associated with decreased or increased IL-23 receptor expression in γ/δ+ T cells, respectively. [J Invest Dermatol] Full Article The Transcription Cofactor c-JUN Mediates Phenotype Switching and BRAF Inhibitor Resistance in Melanoma Most patients with BRAF-mutant metastatic melanoma display remarkable but incomplete and short-lived responses to inhibitors of the BRAF kinase or the mitogen-activated protein kinase kinase (MEK), collectively BRAF/MEK inhibitors. Researchers found that inherent resistance to these agents in BRAF(V600)-mutant melanoma cell lines was associated with high abundance of c-JUN and characteristics of a mesenchymal-like phenotype. [Sci Signal] Abstract Atypical Signaling of Metabotropic Glutamate Receptor 1 in Human Melanoma Cells Investigators determined if the activation of a canonical G protein-dependent signal transduction cascade, which is often used as an output of metabotropic glutamate 1 (mGlu1) receptor activity in neuronal cells, correlated with mGlu1 receptor-mediated melanoma cell viability. [Biochem Pharmacol] Abstract | Graphical Abstract Compound 13, an α1-Selective Small Molecule Activator of AMPK, Potently Inhibits Melanoma Cell Proliferation Scientists studied the potential effect of Compound 13 (C13), a novel α1-selective AMP-activated protein kinase (AMPK) activator, in melanoma cells. C13 potently inhibited proliferation in melanoma cell lines, but not in B10BR melanocytes. [Tumor Biol] Abstract |