Genotype analysis in Hungarian patients with multiple primary melanoma.

Multiple primary melanoma patients (MPMps) have better prognosis and are more prone to genetic predisposition than single melanoma patients. We aimed to compare genetic background (CDKN2A, CDK4, MITF, MC1R) of 43 Hungarian MPMps with their clinicopathological data. We observed a higher rate of synchronous first and second melanoma (MM) (49%) and a higher frequency of non-melanoma tumor co-occurrence (42%) than reported previously. CDKN2A mutation frequency was 4.7% (E69G, R99P). We identified a new human MC1R variant (D117G) and reported MC1R variant distributions in Hungarian MMs for the first time. The rare R163Q was exceptionally common among Hungarian MPMps, a variant otherwise frequent in Asia, but not in Europe. MC1R 'R' carriers showed histopathological signs of a more progressive disease than 'r' carriers did; however, tumor-infiltrating lymphocytes (TILs) in their second melanomas occurred significantly more frequently. Calculating 5-year overall survival, 'R' carriers showed more unfavourable prognosis (87%) than 'r' carriers did (95%).

Gene expression and activity of cartilage degrading glycosidases in human rheumatoid arthritis and osteoarthritis synovial fibroblasts.

INTRODUCTION: Similar to matrix metalloproteinases, glycosidases also play a major role in cartilage degradation. Carbohydrate cleavage products, generated by these latter enzymes, are released from degrading cartilage during arthritis. Some of the cleavage products (such as hyaluronate oligosaccharides) have been shown to bind to Toll-like receptors and provide endogenous danger signals, while others (like N-acetyl glucosamine) are reported to have chondroprotective functions. In the current study for the first time we systematically investigated the expression of glycosidases within the joints. METHODS: Expressions of beta-D-hexosaminidase, beta-D-glucuronidase, hyaluronidase, sperm adhesion molecule 1 and klotho genes were measured in synovial fibroblasts and synovial membrane samples of patients with rheumatoid arthritis and osteoarthritis by real-time PCR. beta-D-Glucuronidase, beta-D-glucosaminidase and beta-D-galactosaminidase activities were characterized using chromogenic or fluorogenic substrates. Synovial fibroblast-derived microvesicles were also tested for glycosidase activity. RESULTS: According to our data, beta-D-hexosaminidase, beta-D-glucuronidase, hyaluronidase, and klotho are expressed in the synovial membrane. Hexosaminidase is the major glycosidase expressed within the joints, and it is primarily produced by synovial fibroblasts. HexA subunit gene, one of the two genes encoding for the alpha or the beta chains of hexosaminidase, was characterized by the strongest gene expression. It was followed by the expression of HexB subunit gene and the beta-D-glucuronidase gene, while the expression of hyaluronidase-1 gene and the klotho gene was rather low in both synovial fibroblasts and synovial membrane samples. Tumor growth factor-beta1 profoundly downregulated glycosidase expression in both rheumatoid arthritis and osteoarthritis derived synovial fibroblasts. In addition, expression of cartilage-degrading glycosidases was moderately downregulated by proinflammatory cytokines including TNFalpha, IL-1beta and IL-17. CONCLUSIONS: According to our present data, glycosidases expressed by synovial membranes and synovial fibroblasts are under negative regulation by some locally expressed cytokines both in rheumatoid arthritis and osteoarthritis. This does not exclude the possibility that these enzymes may contribute significantly to cartilage degradation in both joint diseases if acting in collaboration with the differentially upregulated proteases to deplete cartilage in glycosaminoglycans.

Nitric oxide mediates T cell cytokine production and signal transduction in histidine decarboxylase knockout mice.

Histamine is a key regulator of the immune system. Several lines of evidence suggest the role of histamine in T cell activation and accelerated Th1 immune response is a hallmark of histidine decarboxylase knockout (HDC-KO) mice, with a complete lack of endogenously produced histamine. According to our previous work, T lymphocytes produce NO upon activation, and NO is necessary for effective T cell activation. To study the role of histamine in T cell activation, we investigated cytokine production and T cell signal transduction in HDC-KO and wild-type (WT) mice. In the absence of histamine, an elevated IFN-gamma mRNA and protein levels of splenocytes (p < 0.001; p = 0.001, respectively) were associated with a markedly increased (2.5-fold, p = 0.0009) NO production, compared with WT animals. Furthermore, histamine treatment decreased the NO production of splenocytes from both WT and HDC-KO mice (p = 0.001; p = 0.0004, respectively). NO precursor (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl) amino] diazen-1-ium-1,2-diolate-diethylenetriamine elicited IFN-gamma production (p = 0.0002), whereas NO synthase inhibitors N(G)-monomethyl-L-arginine and nitronidazole both inhibited IFN-gamma production (p = 0.002 and p = 0.01, respectively), suggesting the role of NO in regulating IFN-gamma synthesis. Cytoplasmic Ca(2+) concentration of unstimulated T cells was increased in the HDC-KO mice (p = 0.02), whereas T cell activation-induced delta Ca(2+)-signal was similar in both HDC-KO and WT animals. Our present data indicate that, in addition to its direct effects on T lymphocyte function, histamine regulates cytokine production and T cell signal transduction through regulating NO production.