Effects of Steroid, Retinoid, and Protease Inhibitors on the Formation of Acantholysis Induced in Organ Culture of Skins from Patients with Benign Familial Chronic Pemphigus

Skin explants from two lesional areas and four normal-appearing areas of four patients with benign familial chronic pemphigus (BFCP) were organ cultured with and without various reagents. After 24-h culturing of involved skin with medium only, dissociation of keratinocytes, which was also observed prior to culturing, was exacerbated, and the epidermis became edematous, with a large section detaching from the dermis. These phenomena were not suppressed even when betamethasone, retinol acetate, or camostat mesilate (serine protease inhibitor) was added to the medium. On the other hand, in the cultures of uninvolved skin explants with medium only, widened intercellular spaces were observed 24–48h after initiation of culture, and dissociation of keratinocytes and acantholytic clefts became apparent after 72h. Such culture-induced acantholysis was almost completely suppressed by the addition of betamethasone, but not supressed by the addition of retinol acetate, EDTA, N-ethylmaleimaide, or pepstatin A. Camostat and SBTI incompletely suppressed the acantholysis. These findings suggest the possibility that steroid may reduce blistering and that an organ culture of non-lesional benign familial chronic pemphigus (BFCP) skin may be useful for clarifying the pathogenesis, as well as for discovering new drugs for the treatment of BFCP. Further experiments are required to clarify the role of serine proteases in the acantholysis in this disease

Comparative Study of Hepatocyte Growth Factor/Scatter Factor and Keratinocyte Growth Factor Effects on Human Keratinocytes

Hepatocyte growth factor/scatter factor (HGF/SF) and keratinocyte growth factor (KGF, also designated FGF-7) are paracrine growth factors secreted by mesenchymal cells and active on a variety of epithelial cell types. In this study, the biologic response of keratinocytes to these paracrine growth factors were compared. Stimulation of mitogenesis, migration, plasminogen activator (PA) activity, and fibronectin production were examined using human foreskin keratinocytes cultured in serum-free MCDB 153 medium. Although the two factors stimulated a similar level of proliferation when cells were maintained for 5 d in 1.8 mM Ca++, the peak effect of KGF, observed at 10 ng/ml, was approximately threefold higher than that of HGF/SF when cells were in medium containing 0.15 mM Ca++. Both agents promoted the migration of cells in low-calcium medium (0.08 mM Ca++). However, the magnitude of the response was approximately twofold greater for HGF/SF at 10 ng/ml than KGF at the same concentration. None of the matrix proteins such as type I collagen, type IV collagen, laminin, or fibronectin either stimulated or supressed HGF/SF-or KGF-stimulated kerationocyte migration. Both factors stimulated PA activity was maximal with the addition of 10 ng/ml of either factor. Neither factor increased the production of fibronectin under conditions in which transforming growth factor-β1 was active. These results indicate that HGF/SF and KGF, both recognized as paracrine growth factors, elicit distinctive patterns of response by keratinocytes, implying that they have different roles in epidermal physiology

Ultraviolet B irradiation increases endothelin-1 and endothelin receptor expression in cultured human keratinocytes

AbstractThe effect of ultraviolet B (UVB) irradiation on endothelin-1 (ET-1) and ET receptor expression was examined using cultured normal human keratinocytes. Keratinocytes secreted ET-1 in the medium at a level of 2.1 pg/day/105 cells. UVB irradiation up to 10 mJ/cm2 increased ET-1 secretion 3-fold, and potentiated expression of mRNA for ET-1. Both ETA and ETB receptor mRNAs were detected in keratinocytes, and their expression was up-regulated by 5 mJ/cm2 UVB irradiation

A Case of Thrombotic Thrombocytopenia Purpura Associated with Systemic Lupus Erythematosus: Diagnostic Utility of ADAMTS-13 Activity

Thrombotic thrombocytopenia purpura (TTP) caused by a deficiency in ADAMTS-13 activity is considered to involve a subset of thrombotic microangiopathy (TMA). Although concept of TTP is included under the umbrella of TMA, discrimination of TTP from TMA is occasionally difficult in an autoimmune disorder. Herein, we report a case with TTP associated with systemic lupus erythematosus (SLE). In this case, it was difficult to discriminate TTP from TMA and the measurement of ADAMTS-13 activity was useful for obtaining an accurate diagnosis. SLE patients having thrombocytopenia in complication with anemia should be considered a monitoring of ADAMTS-13 activity even though the patients lacked symptoms of TTP related to the microvascular coagulation

The Excimer Lamp Induces Cutaneous Nerve Degeneration and Reduces Scratching in a Dry-Skin Mouse Model

Epidermal hyperinnervation, which is thought to underlie intractable pruritus, has been observed in patients with atopic dermatitis (AD). The epidermal expression of axonal guidance molecules has been reported to regulate epidermal hyperinnervation. Previously, we showed that the excimer lamp has antihyperinnervative effects in nonpruritic dry-skin model mice, although epidermal expression of axonal guidance molecules was unchanged. Therefore, we investigated the antipruritic effects of excimer lamp irradiation and its mechanism of action. A single irradiation of AD model mice significantly inhibited itch-related behavior 1 day later, following improvement in the dermatitis score. In addition, irradiation of nerve fibers formed by cultured dorsal root ganglion neurons increased bleb formation and decreased nerve fiber expression of nicotinamide mononucleotide adenylyl transferase 2, suggesting degenerative changes in these fibers. We also analyzed whether attaching a cutoff excimer filter (COF) to the lamp, thus decreasing cytotoxic wavelengths, altered hyperinnervation and the production of cyclobutane pyrimidine dimer (CPD), a DNA damage marker, in dry-skin model mice. Irradiation with COF decreased CPD production in keratinocytes, as well as having an antihyperinnervative effect, indicating that the antipruritic effects of excimer lamp irradiation with COF are due to induction of epidermal nerve degeneration and reduced DNA damage

Transcriptional Regulation of ATP2C1 Gene by Sp1 and YY1 and Reduced Function of its Promoter in Hailey–Hailey Disease Keratinocytes

Hailey–Hailey disease (HHD) is a blistering skin disease caused by malfunction of the Ca2+-dependent ATPase, ATP2C1. In this study, key regulatory regions necessary for the expression of the gene encoding human ATP2C1 were investigated. The transient reporter assay demonstrated that region +21/+57 was necessary for activation of the ATP2C1 promoter, and the electrophoretic mobility shift assay demonstrated that the region was recognized by the transcription factors, Sp1 and YY1. In accordance with this result, when Sp1 or YY1 was overexpressed in keratinocytes, an obvious increase in ATP2C1 promoter activity was observed, which was in contrast with the case where a mutant promoter lacking the binding sites for Sp1 and YY1 was used as the reporter. Ca2+-stimulation signal increased nuclear Sp1 proteins and ATP2C1 mRNA levels in normal keratinocytes. In contrast, both these increases were suppressed in keratinocytes from HHD patients. These results indicate that Sp1 and YY1 transactivate the human ATP2C1 promoter via cis-enhancing elements and that incomplete upregulation of ATP2C1 transcription contributes to the keratinocyte-specific pathogenesis of HHD. This is a report describing the regulation of the expression of ATP2C1