Transglutaminase 1 (TGase 1) is an essential enzyme for cornified envelope formation in stratified squamous epithelia. This enzyme catalyzes the cross‐linking of glutamine and lysine residues in structural proteins in differentiating keratinocytes. To gain insight into the preferred substrate structure of TGase 1, we used a phage‐displayed random peptide library to screen primary amino acid sequences that are preferentially selected by human TGase 1. The peptides selected as glutamine donor substrate exhibited a marked tendency in primary structure, conforming to the sequence: QxK/RψxxxWP (where x and ψ represent non‐conserved and hydrophobic amino acids, respectively). Using glutathione S‐transferase (GST) fusion proteins of the selected peptides, we identified several sequences as preferred substrates and confirmed that they were isozyme‐specific. We generated GST‐fused alanine mutants of the most reactive sequence (K5) to determine the residues that were critical for reactivity. Even in peptide form, K5 appeared to have high and specific reactivity as substrate. In situ analysis of mouse skin sections using fluorescence‐conjugated K5 peptide resulted in detection of TGase 1 activity with high sensitivity, but no signal was detected in a TGase 1‐null mouse. In conclusion, we were successful in generating a novel substrate peptide for sensitive detection of endogenous TGase 1 activity in the skin.

In addition to their antibiotic effects, tetracyclines have anti-inflammatory action that is often beneficial in the control of inflammatory skin disorders. In this study, we examined the effects of tetracycline (TET) and two of its derivatives, doxycycline (DOX) and minocycline (MIN), on the production of interleukin-8 (IL-8) elicited by the activation of protease-activated receptor 2 (PAR2) in normal human epidermal keratinocytes (NHEK). In NHEK, the production of IL-8 stimulated by an agonist peptide of PAR2, SLIGKIV-NH 2 , at 100 M was significantly reduced by TET, DOX, or MIN at 5 and 10 M, concentrations that are noncytotoxic. The tumor necrosis factor alpha (TNF-␣)-induced production of IL-8 was synergistically augmented by SLIGKIV-NH 2 , and that synergistic increase in the production of IL-8 was suppressed by 100 nM PAR2-specific small interfering RNA. It was also suppressed by TET, DOX, or MIN but not by the 14-membered-ring macrolide antibiotics erythromycin, roxithromycin, and clarithromycin, which also have anti-inflammatory activities, at 10 M. These results suggest that tetracyclines attenuate the PAR2-IL-8 axis in keratinocytes and thereby effectively modulate proinflammatory responses in the skin.

Although serum levels of S100A8/A9 were increased in all types of psoriasis examined, patients with PA had higher levels of S100A8/A9, probably because of an activated monocyte/macrophage system.

No abstract

Psoriasis is a skin disorder of chronic keratinization characterized by epidermal hyperplasia, hyperkeratosis, and inflammation. However, little is known about the mechanism (s) underlying the hyperplasia with elongated rete ridges characteristic of psoriasis. The p63 transcription factor, a homologue of the p53 tumor suppressor, has been implicated in the maintenance of epidermal stem cells and the stratification of the epidermis. p63 is up-regulated in squamous cell carcinomas with anaplasia, suggesting that it is also associated with epidermal hyperplasia. In this study, we examined the expression of p63 in the remodeling of psoriatic epidermis. Lesional tissues from 17 psoriasis patients in various stages of plaque-type psoriasis and normal skin tissues from five healthy subjects were examined by immunohistochemistry using a monoclonal anti-p63 antibody. Normal epidermis stained positively for p63 in the basal cell layer and in 2 to 4 layers of the spinous cell layer. p63 was positive in the thickened rete ridges of the epidermis even in early psoriatic lesions. As the epidermis elongated, p63-positive cells moved down and were localized in the lower parts of the rete ridges where keratinocytes densely proliferated. From these results, we suggest that p63 may be involved in the early stage of the remodeling process of the psoriatic epidermis as well as in the elongation of the rete ridges.

: Flap transplantation has been an important procedure in plastic and reconstructive surgery to cover and fill various defects. Flap necrosis due to blood circulation failure leads to severe complications, especially in a patient undergoing reconstruction concerning the body cavity after tumor ablation. Surgical procedures for flap transplantation have been further improved and developed. We have reviewed from the random pattern flap to the newest procedure, the perforator flap. Perforator vessels were investigated in the process of development of the fasciocutaneous flap and have become important for blood supply of the skin flap. Blood circulation of the flap has become more stable and reliable than ever with the development and findings of the perforator vessels. Further development of a skin flap will be based on the perforasome concept, which involves the study of the territory and linking of perforator vessels.

No abstract

Protease-activated receptor 2 (PAR2) is a G protein-coupled receptor which mediates a variety of functions in the skin including cutaneous inflammation. SLIGKV-NH(2) , an agonist peptide for PAR2, enhanced the interleukin (IL)-17-induced production of two CXC chemokines, CXCL1 (GRO-α) and CXCL8 (IL-8), in normal human epidermal keratinocytes (NHEK) in a concentration-dependent manner. The enhanced production of those chemokines was suppressed by a PAR2-specific siRNA. The SLIGKV-NH(2) -induced production of both CXCL1 and CXCL8 was markedly reduced by cyclosporine A. The enhanced production of CXCL1 was suppressed by 1α, 24R-dihydroxyvitamin D(3) , an active form of vitamin D(3) , and weakly by glucocorticoids, dexamethasone and clobetasol propionate, whereas production of CXCL8 was not altered by any of those receptor agonists. In psoriatic skin, the thickened upper spinous layer of the epidermis was positive for PAR2 protein and the expression of the IL17A mRNA was increased. These results suggest that the IL-17-induced pro-inflammatory reaction is enhanced by the activation of PAR2 in keratinocytes, and that the effect of PAR2 is differentially modulated by cyclosporine A, the active form of vitamin D(3) and glucocorticoids.