Alkaline phosphatase (ALP) activity was detected in the restricted mesenchymal and epithelial regions in mouse vibrissal follicles. Its localization and strength dramatically changed during the hair cycle. Activity in the dermal papilla (DP) was moderate in very early anagen, reached a maximal level in early anagen, decreased at the proximal region of DP after mid anagen, and was kept at a low level during catagen. The bulbar dermal sheath showed intense ALP activity only in early anagen. Although most bulbar epithelium did not show ALP activity, germinative epidermal cells that were adjacent to the ALP‐negative DP cells became ALP‐positive in mid anagen and rearranged in a single layer so as to encapsulate the DP in mid catagen. During catagen, the outermost layer of bulbar epithelium became ALP‐positive, which could be follicular epithelial precursors migrating from the bulge. Before the initiation of hair formation, ALP activity in the bulbar epithelium rapidly decreased and that in DP increased. These dynamic changes of ALP expression might be related to DP's functions in hair induction and also to reconstruction of the bulbar structure during the hair cycle.

Recently, extracellular vesicle (EV)-mediated cell differentiation has gained attention in developmental biology due to genetic exchange between donor cells and recipient cells via transfer of mRNA and miRNA. EVs, also known as exosomes, play a role in maintaining paracrine cell communication and can induce cell proliferation and differentiation. However, it remains unclear whether adipose-derived stem cells (ASCs) can adopt dermal papilla (DP)-like properties with dermal papilla cell-derived extracellular vesicles (DPC-EVs). To understand the effect of DPC-EVs on cell differentiation, DPC-EVs were characterized and incubated with ASCs, of monolayer and spheroid cell cultures, in combination with the CAO1/2FP medium specialized for dermal papilla cells (DPCs). DPC-like properties in ASCs were initially evaluated by comparing several genes and proteins with those of DPCs via real-time PCR analysis and immunostaining, respectively. We also evaluated the presence of hair growth-related microRNAs (miRNAs), specifically mir-214-5P, mir-218-5p, and mir-195-5P. Here, we found that miRNA expression patterns varied in DPC-EVs from passage 4 (P4) or P5. In addition, DPC-EVs in combination with CAP1/2FP accelerated ASC proliferation at low concentrations and propagated hair inductive gene expression for versican (vcan), alpha-smooth muscle actin (α-sma), osteopontin (opn), and N-Cam (ncam). Comparison between the expression of hair inductive genes (vcan, α-sma, ctnb, and others), the protein VCAN, α-SMA and β-Catenin (CTNB), and hair inductive miRNAs (mir-214-5P, mir-218-5p, and mir-195-5p) of DPC-EVs revealed similarities between P4 DPC-EVs-treated ASCs and DPCs. We concluded that early passage DPC-EVs, in combination with CAP1/2FP, enabled ASCs to transdifferentiate into DPC-like cells.

Our previous report showed that rapid wound closure in Xenopus laevis embryos was associated with a decrease in the extracellular concentration of either Na+ or Cl- ions. In this study, we examined the wound closure in Xenopus embryos when epithelial Na+ channel (ENaC), Na+/K+ ATPase (Na+ pump) or CICs (members of Cl- channel) were blocked by each specific inhibitor. Blockage of ENaC and CIC restricted the rate of wound closure during the first 30 min PW and during the subsequent period, respectively. In contrast, inhibition of Na+ pump had no effect on the rate of wound closure. Furthermore, simultaneous administration of both ENaC and CIC inhibitors resulted in the cumulative reduction of wound closure. Thus, it is plausible that these ion channels play active roles in wound closure in Xenopus embryos. NPPB is known to inhibit both CIC-2 and CIC-3. Immunohistochemical experiments showed that CIC-3, but not CIC-2, was expressed in Xenopus embryos, suggesting that the reduced wound closure by NPPB was due...

Transgenic (TG) mice that have systemically expressed Endo-β-galactosidase C (EndoGalC) have rough and flaky skin. This skin phenotype is detectable around 5 days postnatal and becomes obscure by 2 weeks after birth. Their epidermis is thickened but the dermis and hair follicles are normal in structure. EndoGalC, which removes the terminal Galα1-3Gal disaccharide (αGal epitope), was expressed in the epidermis of TG mice. GS-IB4 lectin staining showed that the αGal epitope did not exist in the epidermis in TG but existed in wild-type (WT) mice. In TG mice, N-acetylglucosamines were exposed by EndoGalC, which is detected using GS-II lectin. To understand the cause of the epidermal thickening and skin phenotype, we examined the proliferation and differentiation of kerationocytes. BrdU-pulse-labeling revealed that proliferating keratinocytes increased approximately three-fold in TG epidermis compared to WT one. In TG epidermis, the expression domain of cytokeratin 14 increased from 1–2 layers to 4–5 layers and co-expressed with cytokeratin 6 and 10 in the upper layers. The layers expressing involucrin and loricrin also increased but those expressing filaggrin and transglutaminase looked normal. The localization of E-cadherin was similar in both TG and WT mice. Although TG mice showed delayed development of the barrier function around 8 days postnatal, they acquired the function by 12 days after birth. These results suggest that the absence of the αGal epitope or the exposed N-acetylglucosamine terminal could play a critical role in the proliferation of basal keratinocytes and differentiation of them into the spinous cells in newborn mice.