The prevalence of scleroderma-type capillary abnormalities, as observed by in vivo microscopy, was determined in 173 patients from three rheumatic disease centers. The patients had a variety of connective tissue diseases: scleroderma (systemic sclerosis) 50; systemic lupus erythematosus 60, mixed connective tissue disease 26; Raynaud's disease 11; other rheumatic disorders 26. Enlarged and deformed capillary loops surrounded by relatively avascular areas, most prominently in the nailfolds, were found in 82% of patients with scleroderma and in 54% with mixed connective tissue disease. The rarity of these abnormalities in systemic lupus erythematosus (2%) despite the presence of Raynaud's phenomenon suggests that they are not an expression of the Raynaud's phenomenon frequently associated with scleroderma and mixed connective tissue disease. The single patient with Raynaud's disease and sclerodermatype capillary changes subsequently developed scleroderma.

The fingers of 75 patients with connective tissue disorders were examined by "wide-field" capillary microscopy. Four diagnostic groups were included in this study: rheumatoid arthritis-28, scleroderma-22, dermatomyositis-8, and systemic lupus erythematosus-17. On the basis of different patterns of elementary microvascular abnormalities and their distribution, 3 distinct groups were recognized among these patients: 1) increased visibility of nailfold subpapillary plexus in rheumatoid arthritis, 2) massive capillary dilatation in scleroderma-dermatomyositis, and 3) focal loss of capillaries and prominence of subpapillary vessels with "punched-out" lesions in systemic lupus erythematosus.

Oncostatin M (OSM), a member of the hematopoietic cytokine family, has been implicated in excessive bone growth and in the process of fibrosis. As part of an ongoing study of the molecular mechanisms of fibrosis, we have investigated the transcriptional regulation of the ␣2(I) collagen gene by OSM in human fibroblasts. An OSM response element was mapped by deletional analysis between base pairs (bp) ؊148 and ؊108 in the ␣2(I) collagen promoter. Further functional analysis of the ␣2(I) collagen promoter containing various substitution mutations revealed that both the basal activity and OSM stimulation of this promoter are mediated by a TCCTCC motif located between bp ؊128 and ؊123. Furthermore, three copies of the 12-bp synthetic ␣2(I) collagen promoter fragment containing the "TCC" motif conferred OSM inducibility to the otherwise unresponsive thymidine kinase promoter. Electrophoretic mobility shift assays demonstrated that the TCCTCC motif constitutes a novel binding site for the transcription factors Sp1 and Sp3. No differences have been observed in in vitro gel shift binding assays between unstimulated and OSMstimulated fibroblasts. However, subtle conformational changes were detected in the region of the promoter surrounding TCC repeats after OSM stimulation using in vivo footprint analysis. In conclusion, this study characterized a dual-function response element that mediates the basal activity and OSM stimulation of the human ␣2(I) collagen promoter.Type I collagen, the most abundant mammalian collagen, consists of two ␣1(I) chains and one ␣2(I) chain that are coordinately expressed (1-3). Excessive deposition of type I collagen, characteristic of many fibrotic disorders (4), most likely results from transcriptional activation of collagen genes in response to cytokines and other factors present in prefibrotic/ inflammatory lesions. The most widely studied cytokine involved in collagen deposition is TGF-␤ 1 ; nonetheless, other cytokines such as IL-4, IL-1, or OSM share many biological effects of TGF-␤ including stimulation of collagen synthesis and may play important roles in extracellular matrix accumulation during fibrotic process, especially immune-mediated fibrosis (5-7).OSM is produced by activated T cells (8) and monocytes (9) and belongs to a subfamily of hematopoietic cytokines that also includes IL-6, IL-11, LIF (leukemia inhibitory factor), and CNTF (ciliary neurotrophic factor). Members of this family bind receptor complexes containing a signal-transducing subunit termed gp130 (10 -12). Interestingly, OSM utilizes a dualreceptor system (13). First, a heterodimeric receptor complex consisting of gp130 and LIF receptor-␤ can be used by both OSM and LIF. A second heterodimeric receptor complex consisting of gp130 and OSM receptor-␤ is activated by OSM only. As a result, some of the biological effects are shared by OSM and LIF, whereas others are OSM-specific.In fibroblasts, OSM stimulates both collagen and glycosaminoglycan production (7). Moreover, OSM has been reported to stimulate the synthesis...

To analyze regulatory elements in the human alpha 2(I) collagen gene (COL1A2) promoter, a series of deletion mutants from -323 to -186 base pairs was tested in transient transfection assays in human fibroblasts. A strong positive responsive element was mapped to a GC-rich region located between base pairs -303 and -271. This region contains three binding sites (GC-boxes) resembling recognition sites for the transcription factor Sp1. Substitution mutations in the GC-boxes abolished binding to the GC-rich region in gel shift analyses and resulted in 90% reduction of promoter activity in transient transfection assays. We demonstrated that transcription factor Sp1 is essential for binding based on the following observations. 1) Sp1 consensus binding site alone competes by binding to the GC-rich region in the DNase I protection assay; 2) both Sp1 consensus binding site and Sp1 antibodies prevent the formation of a DNA-protein complex in the mobility shift assay; 3) anti-Sp1 antibodies recognize a component of the complex competed for by Sp1 consensus binding site.