Ninjurin1 Deletion in NG2-Positive Pericytes Prevents Microvessel Maturation and Delays Wound Healing.

The formation of mature vasculature through angiogenesis is essential for adequate wound healing, such that blood-borne cells, nutrients, and oxygen can be delivered to the remodeling skin area. Neovessel maturation is highly dependent on the coordinated functions of vascular endothelial cells and perivascular cells, namely pericytes (PCs). However, the underlying mechanism for vascular maturation has not been completely elucidated, and its role in wound healing remains unclear.

Gender disparities in academic dermatology in Japan: Results from the first national survey.

Background: A wide gender gap exists in many fields in Japan, including the academic society of dermatology. Women are substantially underrepresented in the highest academic ranks.

Objective: We aimed to clarify the possible factors contributing to the current gender gap in the field of academic dermatology and to recommend necessary measures to decrease the gender gap.

Sphingosine 1-Phosphate Receptor 2 Is Central to Maintaining Epidermal Barrier Homeostasis.

The outer layer of the epidermis composes the skin barrier, a sophisticated filter constituted by layers of corneocytes in a lipid matrix. The matrix lipids, especially the ceramide-generated sphingosine 1-phosphate, are the messengers that the skin barrier uses to communicate with the basal layer of the epidermis where replicating keratinocytes are located. Sphingosine 1-phosphate is a bioactive sphingolipid mediator involved in various cellular functions through S1PR1‒5, expressed by keratinocytes.

Inclusion bodies are not uncommon in angioleiomyoma.

Background: Leiomyomas with eosinophilic intracytoplasmic inclusion bodies have been described in the urinary bladder, brain, gastrointestinal tract, uterus, and oral cavity but not in the skin. Prompted by our recent experience with a case of cutaneous angioleiomyoma with many inclusion bodies, we hypothesized that similar cases might have been previously overlooked.

Methods: We retrospectively reviewed 30 cases of angioleiomyoma and 10 cases of piloleiomyoma focusing on inclusion bodies.

Lipocalin 2: A New Antimicrobial in Mast Cells.

Mast cells (MCs) play a significant role in the innate immune defense against bacterial infection through the release of cytokines and antimicrobial peptides. However, their antimicrobial function is still only partially described. We therefore hypothesized that MCs express additional antimicrobial peptides.

Human Keratinocytes Use Sphingosine 1-Phosphate and its Receptors to Communicate Staphylococcus aureus Invasion and Activate Host Defense.

Sphingosine 1-phosphate (S1P) is a bioactive lipid mediator generated when a cell membrane or its components are damaged by various factors. S1P regulates diverse cell activities via S1P receptors (S1PRs). Keratinocytes express S1PR1-5.

Severe thiopurine-induced leukocytopenia and hair loss in Japanese patients with defective NUDT15 variant: Retrospective case-control study.

Azathioprine (AZA)-metabolizing enzyme gene polymorphism is strongly related to thiopurine-induced leukocytopenia, which has not been well recognized in dermatological practice. We tried to see whether NUDT15 gene polymorphism can be the most susceptible genetic factor for AZA toxicity and the gene screening is beneficial to avoid the adverse events of AZA for the treatment of skin diseases. A retrospective study was carried out on 15 adult Japanese patients who were treated with AZA.

Molecular basis of the skin barrier structures revealed by electron microscopy.

The barrier function of skin is indispensable for terrestrial animals. This function is mainly carried out by the epidermis, more specifically by its granular and cornified layers. The major structural components associated with this function are the intercellular lipid layer, desmosomes, corneodesmosomes, tight junctions, cornified cell envelope and keratin filaments.

RIPK1 downregulation in keratinocyte enhances TRAIL signaling in psoriasis.

Background: Psoriasis, a common inflammatory skin disorder characterized by scaly erythema and plaques, is induced by dysregulation of dendritic cell- and T cell-mediated immune reaction. Receptor-interacting protein kinase 1 (RIPK1) regulates inflammatory signaling in response to stimuli such as TNF-α, TRAIL, and TLRs, resulting in apoptosis, necroptosis and NF-κB activation. However, the physiological relevance in human epidermis remains elusive.

Clinical and molecular implications of structural changes to desmosomes and corneodesmosomes.

Desmosomes provide the main intercellular adhesive properties between epidermal keratinocytes. Their distribution becomes uneven in severe dermatitis, multiple allergies and metabolic wasting syndrome due to desmoglein 1 deficiency and the loss of intercellular adhesion or acantholysis. When keratinocytes differentiate from granular cells into cornified cells, desmosomes are transformed into corneodesmosomes and can provide stronger intercellular adhesion.

Skin microbiome and mast cells.

Microbiotas in the skin have high levels of diversity at the species level, but low phylum-level diversity. The human skin microbiota is composed predominantly of Gram-positive bacteria especially Actinobacteria, which are the dominant bacterial phylum on the skin. Lipoteichoic acid (LTA) is a major constituent of the cell wall of Gram-positive bacteria and is therefore abundant in the skin microbiome.

Incomplete KLK7 Secretion and Upregulated LEKTI Expression Underlie Hyperkeratotic Stratum Corneum in Atopic Dermatitis.

Atopic dermatitis (AD) is a common inflammatory skin disorder. Chronic AD lesions present hyperkeratosis, indicating a disturbed desquamation process. KLK7 is a serine protease involved in the proteolysis of extracellular corneodesmosome components, including desmocollin 1 and corneodesmosin, which leads to desquamation.

The biology and regulation of corneodesmosomes.

The stratum corneum of the epidermis is composed of stacked dead corneocytes embedded in lipid layers and is the main protective shield of the skin. The thickness of the stratum corneum is maintained fairly constantly through the balance between new cell creation and old cell removal. Corneodesmosomes are the main intercellular adhesive structures in the stratum corneum.

Cutaneous necrotizing vasculitis as a manifestation of familial Mediterranean fever.

Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disease, which is characterized by recurrent and paroxysmal fever, peritonitis, arthritis, myalgia, and skin rashes. Although various skin lesions such as "erysipelas-like erythema", urticaria, nonspecific purpura, and subcutaneous nodules have been described, cutaneous vasculitis is rare. We report a Japanese case of sporadic FMF accompanied by cutaneous arteritis at the time of febrile attacks of FMF.

Genetic skin diseases related to desmosomes and corneodesmosomes.

The integrity of the epidermis depends on the cohesion between keratinocytes, and desmosomes are the main adhesion structures. When cells become cornified, desmosomes are modified and transformed into corneodesmosomes. Mutations in the genes encoding desmosomal components underlie several skin diseases including palmoplantar keratoderma and forms of epidermolysis bullosa, indicating the importance of desmosomes as mechanical stress-bearing structures.