Expression of activin A in human keratinocytes at early stages of cultivation

AbstractActivins are members of the TGF-β superfamily and are classified into 3 types: activin A, which consists of a homodimer of βA, activin B, which consists of a homodimer of βB, and activin AB, which consists of a heterodimer of βAβB. We studied the expression of activin mRNAs by RT-PCR in normal human epidermis, cultured keratinocytes, and DJM-1 cells (a squamous cell carcinoma line). We could detect only activin A mRNA (βA) in normal human epidermis. In cultured keratinocyte and DJM-1 cells, activin βA mRNA was observed at 4 h but not at 96 h after plating. Activin A activity was detected in the conditioned medium of DJM-1 cells within 48 h. In addition, although follistatin mRNA was not observed in human epidermis in situ, it was transiently expressed in cultured cells at 4 h after plating. These findings suggest that the expression of these molecules in keratinocytes is associated with cell proliferation. In an in vitro tissue injury model, activin A was observed at the wound edge, where cell migration and proliferation may be activated. In DJM-1 cells cultured for 92 h, βA mRNA was observed 4 h after injury treatment. These findings suggest that activin A acts as a potent inducer of proliferation in vitro, at least in keratinocytes

Interferon-γ Decreases Ceramides with Long-Chain Fatty Acids: Possible Involvement in Atopic Dermatitis and Psoriasis

Ceramide (CER) with long-chain fatty acids (FAs) in the human stratum corneum (SC) is important for the skin barrier functions. Changes in the CER profile have been associated with abnormal permeability of dermatoses such as atopic dermatitis (AD) and psoriasis. In addition, interferon-γ (IFN-γ) has been known to be abundant in both AD and psoriatic skin lesions. In this study, we aimed to identify the mechanism underlying the alteration of FA chain length of CERs in these diseases. Mass spectrometry analysis of CERs in the SC showed that the proportion of CERs with long-chain FAs was significantly lower in AD and psoriasis patients than in healthy controls, and this reduction was more pronounced in psoriasis than in AD. Using cultured human keratinocytes and epidermal sheets, we found that only IFN-γ among various cytokines decreased the mRNA expression of elongase of long-chain fatty acids (ELOVL) and ceramide synthase (CerS), enzymes involved in FA chain elongation. Furthermore, quantitative analysis showed that IFN-γ decreased the levels of CERs with long-chain FAs. These results suggest that IFN-γ decreases CERs with long-chain FAs through the downregulation of ELOVL and CerS and that this mechanism may be involved in the CER profile alteration observed in psoriasis and AD

Sonographic Detection of Subcutaneous Foreign Bodies in 3 Cases

Subcutaneous masses caused by foreign bodies are frequently encountered in daily practice. Although the majority of foreign bodies such as metals can be detected by radiography, substances such as vegetative materials or wood are difficult to detect. To our knowledge, only a few studies have described the sonographic characteristics of foreign bodies. Herein, we report 3 cases where we studied the sonographic characteristics of the foreign bodies in the dermis and subcutaneous tissue. Our results revealed the following 3 foreign bodies: (1) glass, (2) vegetative material, and (3) a pencil core. Thus, sonographic examination is useful for the detection of foreign bodies

Expression of Drebrin, an actin binding protein, in basal cell carcinoma, trichoblastoma and trichoepithelioma

Drebrin, an F-actin binding protein, is known to play important roles in cell migration, synaptogenesis and neural plasticity. Although drebrin was long thought to be specific for neuronal cells, its expression has recently been reported in non-neuronal cells. As for skin-derived cells, drebrin was shown to be enriched at adhering junctions (AJs) in cultured primary keratinocytes and also be highly expressed in basal cell carcinoma (BCC) cells. Since BCC and two types of benign neoplasm, trichoblastoma and trichoepithelioma, are considered to derive from the same origin, follicular germinative cells, it is sometimes difficult to morphologically distinguish BCC from trichoblastoma and trichoepithelioma. In this study, we performed immunohistochemical staining of drebrin in BCC, trichoblastoma and trichoepithelioma, to examine whether drebrin could serve as a biomarker for BCC diagnosis. In western blotting, drebrin was detected highly and moderately in the lysates from a squamous cell carcinoma cell line, DJM-1, and normal human epidermis, respectively. In immunofluorescence analyses, drebrin was colocalized with markers of AJs and tight junctions in DJM-1 cells and detected at cellcell junction areas of human normal epidermis tissue. We then examined the distribution patterns of drebrin in BCC, trichoblastoma and trichoepithelioma. In BCC tissues, intense and homogeneous drebrin expression was observed mainly at tumor cell-cell boundaries. In contrast, drebrin was stained only weakly and nonhomogeneously in trichoblastoma and trichoepthelioma tissue samples. For differential diagnosis of BCC, drebrin may be a novel and useful marker