Yoko Kawa

Methotrexate inhibits proliferation and regulation of the expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 by cultured human umbilical vein endothelial cells

Summary Background The mechanism by which a low dose of methotrexate (MTX) works to treat psoriasis is not clear. The overexpression of cell adhesion molecules on dermal vessels is important in the pathogenesis of psoriasis and is probably induced by upregulation of tumour necrosis factor (TNF)‐α.

Cutaneous extramedullary hematopoiesis in myelofibrosis

Erythematous papulonodules that resembled a malignant lymphoma developed in a 62-year-old man. Further examination revealed that he had primary myelofibrosis with cutaneous extramedullary hematopoiesis. All three marrow elements (myeloid, erythroid, and megakaryocytic series) were present in the skin lesions. Although extramedullary hematopoiesis of the skin is a rare complication of myelofibrosis, 13 similar cases have been reported. In nine cases, including ours, all three marrow elements were present in the cutaneous lesions.

Stimulation of the proliferation and differentiation of mouse pink-eyed dilution epidermal melanocytes by excess tyrosine in serum-free primary culture

The epidermal cell suspensions of the neonatal dorsal skin derived from wild type mouse at the pink‐eyed dilution (p) locus (black, C57BL/10JHir‐P/P) and their congenic mutant mouse (pink‐eyed dilution, C57BL/10JHir‐p/p) were cultured with a serum‐free melanocyte growth medium supplemented with additional L‐tyrosine (Tyr) from initiation of the primary culture. L‐Tyr inhibited the proliferation of P/P melanocytes in a dose‐dependent manner, whereas L‐Tyr stimulated the proliferation of p/p melanoblasts and melanocytes regardless of dose. On the other hand, L‐Tyr stimulated (P/P) or induced (p/p) the differentiation of epidermal melanocytes in a dose‐dependent manner. In both P/P and p/p melanoblasts and melanocytes cultured with 2.0 mM L‐Tyr for 14 days, slight increases in contents of eumelanin marker, pyrrole‐2,3,5‐tricarboxylic acid (PTCA) and pheomelanin marker, aminohydroxyphenylalanine (AHP) were observed. The average number of total melanosomes (stages I, II, III, and IV) per P/P melanocyte was not changed by L‐Tyr treatment, but the proportion of stage IV melanosomes in the total melanosomes was increased. On the contrary, in p/p melanoblasts and melanocytes L‐Tyr increased dramatically the number of stage II, III, and IV melanosomes as well as the proportion of stage III melanosomes. Contents of PTCA and eumelanin precursor, 5,6‐dihydroxyindole‐2‐carboxylic acid (DHICA) of cultured media in p/p melanocytes were much more greatly increased than in P/P melanocytes. However, contents of AHP and pheomelanin precursor, 5‐S‐cysteinyldopa (5‐S‐CD) of cultured media in p/p melanocytes were increased in a similar tendency to P/P melanocytes. These results suggest that p/p melanocytes in the primary culture are induced to synthesize eumelanin by excess L‐Tyr, but difficult to accumulate them in melanosomes. J. Cell. Physiol. 191: 162–172, 2002.

T Cells and Mast Cells as a Major Source of Interleukin-13 in Atopic Dermatitis

Background: Interleukin (IL)-13 is a T-cell-derived cytokine that shares several functions with IL-4, including the induction of immunoglobulin E synthesis. Recent studies suggest that cytokines expressed locally in the skin play several critical roles in atopic dermatitis (AD), however, little is known about the role of IL-13 in AD lesions. Objectives: The present study was designed to characterize the involvement of IL-13 in AD in the skin and peripheral blood mononuclear cells (PBMC). Methods: Using lesional and nonlesional skin from adult AD patients and normal skin from healthy volunteers, we performed RT-PCR, in situ RT and immunostaining to determine the IL-13 expression at the mRNA and protein levels. The actual numbers of IL-13 expressing cells in biopsy specimens were counted under the microscope. IL-13 mRNA expression in PBMC from AD patients and healthy volunteers was examined by RT-PCR analysis. Results: IL-13 mRNA expression was detected by RT-PCR in lesional and nonlesional skin and in PBMC from AD patients, but not in normal skin or PBMC from healthy volunteers. In AD lesional skin, numerous IL-13 mRNA-positive cells were demonstrated by in situ RT, and similar numbers of IL-13-positive cells were also detected immunohistochemically. Smaller numbers of IL-13-positive cells were observed in AD nonlesional skin and in normal skin. The differences in the numbers of IL-13-expressing cells between lesional and nonlesional skin were statistically significant. Double immunostaining revealed that IL-13 was produced in approximately 40% of T cells and 20% of mast cells in AD lesional skin, suggesting that T cells and mast cells are major sources of IL-13 in AD lesions. Conclusion: IL-13 may play a local as well as a systemic role in the development of AD lesions.

Pathogenesis of Mucocutaneous Lesions in Behçet's Disease

Behcets disease (BD) is characterized by recurrent oral aphthae, skin lesions, eye lesions, and genital ulceration. To determine the pathogenesis of BD, we performed histological and immunohistochemical studies of these mucocutaneous lesions, an assay of neutrophil activity, and HLA typing.

Serum levels of soluble stem cell factor and soluble KIT are elevated in patients with atopic dermatitis and correlate with the disease severity

Background Mast cell infiltration in skin lesions of atopic dermatitis (AD) is considered to play an important role in the pathogenesis of the disease. The most common factor that stimulates mast cell growth, migration and differentiation is stem cell factor (SCF), and the interaction of SCF and its receptor, KIT (tyrosine kinase transmembrane receptor), appears to be the key event in the recruitment and proliferation of mast cells.

Production of interleukin-1-alpha and -beta by human peripheral polymorphonuclear neutrophils.

The mechanism of the production of interleukin-1 (IL-1) by human peripheral polymorphonuclear neutrophils (PMN) was investigated. Supernatants of PMN stimulated with 30 micrograms/ml lipopolysaccharide (LPS) were used as extracellular IL-1 and supernatants of their lysate as intracellular IL-1 source. IL-1 activity was measured by the C3H/HeJ thymocyte co-mitogenic assay. The supernatants from PMN stimulated with LPS for 72 h showed IL-1 activity which had an apparent molecular weight of 15-20 kilodaltons and pI of 5.0 and more than 8.5. It was neutralized with anti-IL-1 antibodies and it lacked IL-2 activity. Our time course study of the IL-1 assay with neutralization by anti-IL-1-alpha and -beta antibodies indicated that the extracellular IL-1-beta activity appeared predominantly in the early incubation periods, whereas alpha activity appeared predominantly in the late periods. Intracellular IL-1-alpha but not beta activity was detected mainly at the intermediate incubation periods. These data indicate that PMN stimulated with LPS produce both IL-1-alpha and -beta, and release IL-1-beta first and IL-1-alpha later.

CDW49B/CD29 INTEGRIN COMPLEX MEDIATES THE DIFFERENTIATION OF HUMAN ENDOTHELIAL CELLS INTO CAPILLARY-LIKE STRUCTURES IN VITRO

We have investigated different beta-1 integrins (CDw49/CD29) on human umbilical vein endothelial cells (HUVEC) with regard to their roles in modifying the morphological structure of these cells on/in matrigel. The inhibition of matrigel-induced capillary formation by antibodies against subunits of beta-1 integrins was examined quantitatively using a digital analyzer. Antibodies to CDw49b and CD29 (common beta chain) caused a marked inhibition of capillary formation (up to 70%) in a dose-dependent manner, whereas antibodies to CDw49d, CDw49e and CDw49f were less inhibitory. We also examined the appearance of HUVEC cultured in matrigel. HUVEC suspended in matrigel for 24 h formed extended cell processes which connected, resulting in the formation of a capillary network. In contrast, fibroblasts cultured in matrigel showed only bipolar extensions without cell-cell contact. After 48 h in culture in matrigel, some HUVEC showed the capillary-unit of a lumen encircled by EC which may mimic the basic putative unit in the formation of capillaries. However, HUVEC pretreated with antibodies to CDw49b and CD29 failed to form significant processes and a hollow lumen. These phenomena may illustrate the importance of endothelial cell-basement membrane matrix interaction (through integrins, especially CDw49b/CD29 complex) occurring during differentiation of endothelial cells in angiogenesis.

A case of subcutaneous sparganosis: therapeutic assessment by an indirect immunofluorescence antibody titration using sections of the worm body obtained from the patient

SIR, A 40-year-old man reported the slow progressive appearance, during the previous 6 years, of pruritic erythematous lesions on the trunk, buttock, abdomen, axilla, genital area and forearm (Fig. 1a). Lesions consisted of follicular papules, comedones, milia and cysts. Lesional areas were alopecic (Fig. 1b), and diffuse alopecia was also present on the scalp and beard area, along with comedones and cysts. The patient reported severe skin dryness, especially in the involved areas. No impairment of salivary or lacrimary function was noted. Serological and haematological tests were all normal or negative. Because of the diffuse presence of cysts and comedones, a diagnosis of chloracne had been made in another institution; the clinical diagnosis was confirmed histologically by the presence of infundibular cysts and a granulomatous foreign body reaction to keratin scales. A further biopsy was performed: the most striking histological feature was a lymphocytic infiltrate involving eccrine glands and coils along with a characteristic epithelial hyperplasia (Figs 1c,d). This picture fits perfectly with that reported in the literature as being characteristic of syringolymphoid hyperplasia, also known as syringotropic mycosis fungoides or syringotropic cutaneous T-cell lymphoma (CTCL). The hair follicles were involved by the lymphocytic infiltrate in a manner similar to that of the eccrine glands. Follicles were surrounded by a dense lymphocytic infiltrate, with extensive exocytosis. Occasional Pautrier microabscesses were evident in the follicular sheath. This pattern is that of pilotropic mycosis fungoides, a form of folliculotropic CTCL. Many follicles were entirely trans-

Melanocyte precursors express elastin binding protein and elastin-derived peptide (VGVAPG) stimulates their melanogenesis and dendrite formation

BACKGROUND In congenital or acquired dermal melanocytosis, attachment of melanocyte with elastic fiber was shown in electron microscopy of unknown biological meaning. We hypothesize elastin-derived peptide may play a role in activating dermal melanocyte precursors. OBJECTIVES This study was designed to determine: (i) whether melanocyte precursors express elastin binding protein (EBP); (ii) ontogenic expression of EBP and elastin in murine embryonic skin; (iii) the effects of elastin-derived peptide (VGVAPG) on melanocyte precursors. METHODS Using immunohistochemistry or Western blot to identify EBP on murine embryonic sections, neural crest cell (NCC) primary culture explants, or two melanocyte precursor cell lines, NCCmelb4 and NCCmelan5. NCC explants or cells were treated with VGVAPG to compare its effect on proliferation, dendrite formation, melanosome maturation and tyrosinase mRNA expression of melanocyte precursors. RESULTS EBP was immunostained on c-kit+ melanocyte precursors. 67kDa EBP protein was immunoblotted on NCCmelb4 and NCCmelan5 cells. EBP was expressed early at embryonic day (E) 9.5, but elastin appeared later at E12.5 skin. VGVAPG increased DOPA-positive cell number and enhanced their dendrite formation in NCC explants. Electron microscopy showed advanced melanosome maturation in NCC explants or cells treated with VGVAPG. VGVAPG enhanced tyrosinase mRNA expression in NCCmelan5 cells. CONCLUSIONS Melanocyte precursors expressed EBP. VGVAPG stimulated their melanogenesis and dendrite formation. In the developmental journey interaction between elastin and EBP-expressed melanocyte precursors in embryos happened mainly since the stage of tertiary melanoblasts. These findings first provide biological evidences for the interaction between melanocyte and elastic fiber.