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Platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β) have been suggested to play important roles in wound healing. We investigated the effect of TGF-β1 on the mitogenic and chemotactic activities of PDGF A-chain homodimer (PDGF-AA) and B-chain homodimer (PDGF-BB) in primary cultures of human skin fibroblasts. TGF-β1 inhibited the growth-promoting activity of both PDGFs. Proliferative responses to basic fibroblast growth factor and epidermal growth factor were also restricted by TGF-β1. A Boyden chamber chemotaxis assay revealed that the chemotactic migration to PDGF-AA was inhibited by TGF-β1 pretreatment, but in contrast, the response to PDGF-BB was not affected by the same treatment. Western blot analysis showed that TGF-β1 downregulated PDGF α-receptors, but not β-receptors, indicating that the isoform-specific inhibition of chemotaxis is related to differential effects of TGF-β1 on PDGF receptor expression. The present findings suggest that TGF-β1 may act antagonistically towards PDGFs in humans under certain conditions, and this antagonistic nature of TGF-β1 must be considered when it is applied to human wounds as a therapeutic agent. [ABSTRACT FROM AUTHOR]

Antibodies to U1 ribonucleoproteins (RNP) have been detected in serum from patients with various autoimmune diseases. However, the presence of anti-U1RNP antibodies in patients with localized scleroderma has not been reported. In this study, we examined the frequency of anti-U1RNP antibodies using immunoprecipitation of U small nuclear RNAs and determined the antigen specificity by immunoblotting. Of 70 serum samples from patients with localized scleroderma, 2 (3%) immunoprecipitated U1 small nuclear RNA. Indirect immunofluorescence using HEp-2 cells as substrate showed coarse speckled nuclear fluorescence without nucleolar staining in both of the samples positive for anti-U1RNP antibodies. In addition, the presence of anti-U1RNP antibodies in each serum sample was confirmed by immunodiffusion against HeLa cell extracts. Immunoblotting analysis showed anti-70 kDa antibodies in each serum sample. This reaction against 70 kDa protein in the patients with localized scleroderma was analogous to that in patients with systemic sclerosis or mixed connective tissue disease. Both patients with positive serum were diagnosed as having linear scleroderma, but neither had evidence of Raynaud’s phenomenon or sclerodactyly. These results indicate that the presence of anti-U1RNP antibodies is one of the serological abnormalities in localized scleroderma, and that the mechanism of induction of anti-U1RNP antibodies in patients with localized scleroderma might be similar to that in patients with systemic sclerosis and mixed connective tissue disease. [ABSTRACT FROM AUTHOR]

Serum containing anti-U1RNP antibodies reacts with the nuclear matrix, the relatively insoluble component of the cell nucleus, in addition to U1RNP. In this study, we determine the serum titer and clinical correlations of antinuclear matrix antibodies in samples from patients with anti-U1RNP antibodies. The patients with anti-U1RNP antibodies were classified as having mixed connective tissue disease (MCTD, 15 patients), systemic sclerosis (SSc, 12 patients), systemic lupus erythematosus (SLE, 7 patients), and undifferentiated CTD (UCTD, 9 patients). Antinuclear matrix antibodies were detected using indirect immunofluorescence staining on HCl-treated HEp-2 cells. The antinuclear matrix antibody titer was significantly higher in serum from patients with MCTD or SSc than in serum from patients with SLE or UCTD. The antinuclear matrix antibody titer was significantly increased in serum from patients with sclerodactyly, pitting scars, contracture of the phalanges, and decreased carbon monoxide diffusion capacity. Thus, a higher titer of antinuclear matrix antibodies in serum from patients with anti-U1RNP antibodies may be associated with a clinical diagnosis of MCTD or SSc rather than a diagnosis of SLE or UCTD. [ABSTRACT FROM AUTHOR]