Heterogeneity of collagen synthesis in normal and systemic sclerosis skin fibroblasts. Increased proportion of high collagen-producing cells in systemic sclerosis fibroblasts.

OBJECTIVE: The goal of this study was to quantitatively analyze the distribution of collagen synthesis in normal and systemic sclerosis (SSc) fibroblast populations in order to determine the extent of activation in SSc populations. METHODS: We used quantitative in situ hybridization to assess the population distribution of type I collagen synthesis. Fibroblast cultures were derived from both clinically involved and uninvolved skin regions of patients with SSc, and from healthy adults, and assessed for levels of alpha 1(I) procollagen messenger RNA (mRNA). RESULTS: Dermal fibroblasts from both patients with SSc and normal adults were heterogeneous for distribution of alpha 1(I) procollagen mRNA when assessed by in situ hybridization, with a wide range of grains per cell. In contrast, clones of neonatal fibroblasts showed a relatively homogeneous distribution of grain counts. Involved SSc skin fibroblasts had a larger proportion of cells in the high collagen-producing mRNA subpopulation (mean +/- SEM 28.4 +/- 6.85%), compared with normal fibroblasts (1.75 +/- 1.44%) and uninvolved fibroblasts (9.6 +/- 6.73%). Conversely, within the low collagen-producing mRNA subpopulation, involved fibroblasts had a smaller proportion of cells (mean +/- SEM 14.0 +/- 5.63%) than did uninvolved fibroblasts (37.8 +/- 13.69%), while normal fibroblasts had a majority of the cells in this subpopulation (53.5 +/- 8.68%). CONCLUSION: These results suggest that only a specific subset of fibroblasts are activated in SSc, as evidence by an increased proportion of cells with high levels of alpha 1(I) procollagen mRNA. Differences between the SSc and normal fibroblast populations appeared to be quantitative rather than qualitative. This may be a result of either clonal selection or selective activation in the pathogenesis of SSc.

Increased collagen synthesis in skin fibroblasts from patients with primary hypertrophic osteoarthropathy. Evidence for trans-activational regulation of collagen transcription.

OBJECTIVE: To investigate collagen synthesis in skin fibroblasts from patients with primary hypertrophic osteoarthropathy (HOA), a disorder characterized clinically by skin thickening. METHODS: Collagenase-digestible protein, messenger RNA (mRNA) levels, and transcriptional activity of the alpha 1(I) procollagen gene were assessed in skin-derived fibroblast lines. RESULTS: Compared with fibroblasts from uninvolved skin, fibroblasts from involved skin had elevated levels of collagen synthesis and alpha 1(I) procollagen mRNA, and increased transcriptional activity of the alpha 1(I) procollagen promoter. CONCLUSION: Abnormalities of collagen synthesis in fibroblasts from patients with primary HOA can be accounted for, at least in part, by a trans-activated up-regulation of collagen transcription.

Regulation of ICAM-1 expression and function in human dermal fibroblasts by IL-4.

ICAM-1 is found on the surface of many hematopoietic and nonhematopoietic cells and can function as an adhesive ligand for the integrin, leukocyte function-associated molecule-1 (LFA-1, CD11a/CD18). ICAM-1/leukocyte function-associated molecule-1 interaction has been shown to be of importance in many immune-mediated cell-cell adhesion reactions. In vitro, unstimulated human fibroblast cell cultures express low levels of ICAM-1. Using ELISA, cytofluorography, electron microscopy, Northern analysis, and an in vitro cell adherence assay, we demonstrate that treatment of human dermal fibroblasts with the cytokine IL-4 leads to an increase in cell surface ICAM-1 expression that is under transcriptional control as well as increased fibroblast adhesion to LFA-1-bearing T lymphocytes. The kinetics of increased ICAM-1 expression induced by IL-4 paralleled the increase in ICAM-1-dependent T lymphocyte adhesion. The increase in T cell adhesion was determined to be due to the effects of IL-4 on the fibroblasts and not the adhering T cells. Treatment of fibroblasts with IL-4 also resulted in enhanced binding of human rhinovirus, a recently reported additional ligand for ICAM-1. Virus binding was IL-4 dose dependent and could be inhibited with mAb to ICAM-1. Both the expression of ICAM-1 and the ICAM-1-dependent increase in T lymphocyte adhesion that was induced by IL-4 could be inhibited by preexposure of the fibroblasts to either IL-1 or IL-6, suggesting that multiple cytokines can have both positive and negative effects on human fibroblast ICAM-1 expression and function.

Immunophenotypization of cells involved in local immune response and serum antibodies in cephalosporin-treated mice.

The in vivo potency of cefodizime (HR 221), tiprotimod (a new synthetic thiazole derivative of HR 221, HBW 538) and cefotaxime to modulate the initiation of immune response in the draining lymph node (LN) after subcutaneous injection of SRBC was evaluated. The timing and sequence of events in the regional LN was investigated by immunophenotypization of node cells with monoclonal antibodies, and the systemic reaction was estimated as primary antibody response to SRBC. From the results it is possible to conclude that: (1) subcutaneous administration of a small dose (2.5-3.0 mg/kg) of cephalosporins, together with antigen, enhanced primary antibody production and persistence; (2) the increase in serum antibodies was preceded by a change in percentage of L3T4+ cells within the regional (popliteal) lymph node. In comparison to antigen alone, cephalosporins (during early immune response) increased the percentage of L3T4+ cells; (3) LN cellularity was strongly enhanced by cephalosporins; (4) cefotaxime influenced the kinetics of the cellularity and the L3T4/Lyt-2 index differently than cefodizime and HBW 538. HBW 538 had either a similar or stronger effect than cefodizime, as judged by the adjuvant effect on antibody production and the appearance of L3T4+ cells during the immunizing period.