CD80CD86 deficiency disrupts regulatory CD4+FoxP3+T cell homoeostasis and induces autoimmune-like alopecia.

Alopecia areata (AA) is an autoimmune disease that results in spot baldness in humans. Adequate animal models for AA are currently lacking. The objective of this study was to elucidate the mechanism of autoimmune-like alopecia (ALA) in C57BL/6.CD80CD86-deficient (B6.CD80CD86-/- ) mice. Incidence and severity of alopecia were analysed in 58 B6.CD80CD86-/- mice using histological examination, flow cytometry, multiplex enzyme-linked immunosorbent assay, quantitative RT-PCR and CD25 inhibition test. Both male and female B6.CD80CD86-/- mice showed almost 100% incidence of hair loss at 40 weeks of age. Moreover, CD4+FoxP3+Treg (Treg) cell population in B6.CD80CD86-/- mice was significantly lower than in B6 mice, which presumably underlined autoimmune reaction. Histologically, B6.CD80CD86-/- mice showed CD4+ and CD8+ T-cell infiltration around terminal follicle region and exhibited hair follicle destruction in the anagen or catagen stage. Negative correlation between the number of CD4+FoxP3+ Tregs and ALA was confirmed by the CD25 depletion test in B6 mice, as follicle destruction was similar to that observed in B6.CD80CD86-/- animals. CD80CD86 deficiency disrupted CD4+FoxP3+ Treg homoeostasis and prompted the development of ALA. We demonstrated that B6.CD80CD86-/- mice might have several advantages as an ALA model, because they exhibited high incidence of disease phenotype and epipathogenesis similar to that observed in human AA.

5-Bromo-2'-deoxyuridine induced effluvium via p53-mediated CD326-positive keratinocyte apoptosis in C57BL/6 mice.

Anagen effluvium develops because of disturbances in the hair follicle cycle, leading to acute and severe hair loss in humans. The objective of this study was to establish a mouse model of anagen effluvium by 5-bromo-2'-deoxyuridine (BrdU) treatment, and evaluate the pathological changes and underlying mechanisms. We treated 9-10-day-old pups and 3-7-week-old C57BL/6 mice with BrdU. After successfully inducing hair loss in the neonatal pups, microscopic, immunohistochemical and flow cytometry analyses were conducted. BrdU induced early onset alopecia in neonates and caused epidermal thickening and hair shaft breakage. BrdU appeared to incorporate the CD326-positive keratinocyte layer and induced p53-related apoptosis. Keratinocyte apoptosis caused immune cell infiltration in the dermal region; M2 macrophages and neutrophils were dominant. The BrdU-induced hair loss was dose-dependent, and alopecia was visible at a dose range of 25-200 µg/g bodyweight. The BrdU-induced anagen effluvium mouse model is novel and easily established by administrating four simple BrdU injections to pups; these mice showed synchronized onset of alopecia symptoms with little individual variation. Moreover, this model showed an alopecia phenotype similar to that of human anagen effluvium with acute, severe and widespread hair loss.

The accessory proteins REEP5 and REEP6 refine CXCR1-mediated cellular responses and lung cancer progression.

Some G-protein-coupled receptors have been reported to require accessory proteins with specificity for proper functional expression. In this study, we found that CXCR1 interacted with REEP5 and REEP6, but CXCR2 did not. Overexpression of REEP5 and REEP6 enhanced IL-8-stimulated cellular responses through CXCR1, whereas depletion of the proteins led to the downregulation of the responses. Although REEPs enhanced the expression of a subset of GPCRs, in the absence of REEP5 and REEP6, CXCR1 was expressed in the plasma membrane, but receptor internalization and intracellular clustering of ß-arrestin2 following IL-8 treatment were impaired, suggesting that REEP5 and REEP6 might be involved in the ligand-stimulated endocytosis of CXCR1 rather than membrane expression, which resulted in strong cellular responses. In A549 lung cancer cells, which endogenously express CXCR1, the depletion of REEP5 and REEP6 significantly reduced growth and invasion by downregulating IL-8-stimulated ERK phosphorylation, actin polymerization and the expression of genes related to metastasis. Furthermore, an in vivo xenograft model showed that proliferation and metastasis of A549 cells lacking REEP5 and REEP6 were markedly decreased compared to the control group. Thus, REEP5 and REEP6 could be novel regulators of G-protein-coupled receptor signaling whose functional mechanisms differ from other accessory proteins.

The effect of a "push-pull" structure on the turn-on fluorescence of photochromic thio-ketone type diarylethenes.

a series of diarylethene compounds with a thiophene bridging unit have been synthesized to investigate the relationship between molecular structure and photochromic properties. In particular, the fluorescence properties related to compound 1 were investigated. The results showed that a six-membered ring carrying an electron-donating sulfur atom and an electron-withdrawing carbonyl group is necessary to form a "push-pull" system for the fluorescence of 1.

Photoswitchable fluorescent diarylethene in a turn-on mode for live cell imaging.

A new diarylethene-derived photochromic compound, with little cytotoxicity, plasma membrane-permeability, and efficient photoswitchability in cells upon alternative UV and visible light irradiation, was synthesized and applied to live cell imaging.