Pseudoscleroderma associated with lung cancer: correlation of collagen type I and connective tissue growth factor gene expression.

Pseudoscleroderma as a paraneoplastic syndrome is a rare disease. We report here a patient with lung cancer (undifferentiated squamous cell carcinoma), who developed acrosclerosis. Using in situ hybridization, marked expression of alpha1(I)-collagen and connective tissue growth factor (CTGF) mRNA was found in fibroblasts scattered throughout the dermis. However, transforming growth factor (TGF)-beta1 expression was not detected. The pattern of CTGF gene expression and collagen synthesis was similar to that in systemic scleroderma. The absence of TGF-beta1 mRNA could indicate that tumour-derived factors induce the expression of CTGF.

Expression of TGF-beta 1, -beta 2 and -beta 3 in localized and systemic scleroderma.

Scleroderma is a generalized or localized disorder which leads to fibrosis of the affected organs. TGF-beta has been implicated as a causal agent in its pathogenesis. In mammals, TGF-beta comprises a family of three members, beta 1, beta 2 and beta 3. Since cutaneous wound healing is thought to result either in formation of a scar or in scar-free tissue regeneration, depending on the relative amounts of the beta 3 isoform, the expression of all three isoforms was studied in skin biopsies of patients with either localized or systemic scleroderma. mRNA for all three isoforms was detected in inflammatory skin areas of both disease forms, but never in sclerotic or healthy skin. Immunohistochemical analysis confirmed expression of beta1 and beta 2 proteins in inflammatory skin of patients, whereas beta 3 protein appeared to be present in the subepidermal area and also found throughout the dermis of patients and healthy dermis as well.

Fibroblast expression of collagen integrin receptors alpha1beta1 and alpha2beta1 is not changed in systemic scleroderma.

The skin of patients with systemic scleroderma (SSc) is characterized by excessive extracellular matrix deposition in the dermis. As collagens represent the major structural component, we used fluorescence-activated cell sorter analysis to study the levels of collagen receptors expressed at the surface of fibroblasts derived from involved skin areas. In contrast to previous reports, no differences in the expression of alpha1, alpha2 or beta1 integrin subunits, which constitute the major collagen receptors on fibroblasts, were detected on SSc fibroblasts as compared with normal control fibroblasts. Variation of cell culture conditions, e. g. passage number (from 2 to 10), seeding density, cell cycle or serum concentration, did not change this result. These observations indicate that any abnormal response of SSc fibroblasts to their matrix environment is not controlled at the level of receptor expression.

Serum xylosyltransferase: a new biochemical marker of the sclerotic process in systemic sclerosis.

UDP-D-xylose:proteoglycan core protein beta-D-xylosyltransferase (EC2.4.2.26) is the initial enzyme in the biosynthesis of chondroitin sulfate and dermatan sulfate proteoglycans in fibroblasts and chondrocytes. Secretion of xylosyltransferase into the extracellular space was determined in cultured human dermal fibroblasts. A more than 6-fold accumulation of xylosyltransferase activity in cell culture supernatant was observed (day 1, 0.6 microU per 106 cells; day 9, 4.1 microU per 106 cells); however, intracellular xylosyltransferase activity remained at a constant level (0.4 microU per 106 cells). Exposure of human chondrocytes to colchicine led to a 3-fold decreased level of xylosyltransferase and chondroitin-6-sulfate concentration in cell culture. Specific xylosyltransferase activity and chondroitin-6-sulfate concentration decreased in a concentration-dependent manner and in parallel in culture medium and accumulated 5-fold in cell lysates indicating that xylosyltransferase is secreted simultaneously into the extracellular space with chondroitin sulfate proteoglycans. Xylosyltransferase activities were determined in serum samples of 30 patients with systemic sclerosis. Xylosyltransferase activities in female (mean value 1.28 mU per liter, 90% range 1.10-1.55 mU per liter) and male patients (mean 1.39 mU per liter, 90% range 1.16-1. 57 mU per liter) with systemic sclerosis were significantly increased in comparison with blood donors of a corresponding age. Furthermore, xylosyltransferase activity was correlated with the clinical classification of systemic sclerosis. Female patients with diffuse cutaneous systemic sclerosis showed higher serum xylosyltransferase activities than patients with limited systemic sclerosis. These results confirm that the increase of proteoglycan biosynthesis in sclerotic processes of scleroderma is closely related to an elevated xylosyltransferase activity in blood and demonstrate the validity of xylosyltransferase as an additional diagnostic marker for determination of sclerotic activity in systemic sclerosis.

Up-regulation of keratin 17 expression in human HaCaT keratinocytes by interferon-gamma.

The immortalized human keratinocyte cell line HaCaT was used to assess the effect of interferon-gamma (IFN-gamma) on expression of keratin K17. Both IFN-gamma and K17 have been implicated in the pathophysiology of psoriasis. Western and quantitative enzyme-linked immunosorbent assay analyses demonstrated increasing induction of K17 protein by 48 h exposure to IFN-gamma at concentrations of 10, 50, and 250 U/ml. At 50 U/ml IFN-gamma, immunohistochemical analysis revealed numerous K17-positive foci, whereas in situ hybridization demonstrated K17 message in the majority of cells. In addition, at low (5 U/ml) concentrations of IFN-gamma, cell proliferation and protein synthesis decreased, as determined by 3H-thymidine labeling and 14C-amino acid uptake. These data suggest that aberrant K17 expression observed in psoriatic lesions may be a consequence of IFN-gamma overexpression, and that the HaCaT cell line may be a useful in vitro model system to elucidate the underlying mechanisms.