INTERFERON GAMMA REGULATION OF DENOVO PROTEIN-SYNTHESIS IN HUMAN DERMAL FIBROBLASTS IN CULTURE IS ANATOMIC SITE DEPENDENT

The propensity of the skin of the lower anterior leg to be involved in Graves' dermopathy prompted an examination of the specific protein synthesis and response to interferon gamma in cultured fibroblasts from this area. Confluent cultures from normal skin of the lower leg and from the abdomen of the same three donors were pulse labeled with [S-35]methionine for 3 h and subjected to two-dimensional protein gel electrophoresis and fluorography. Protein spots were mapped using a computer-driven program and the relative densities of the resolvable spots analyzed. Fibroblasts from the two anatomic sites display distinct patterns of de novo protein synthesis. Of the 157 abundant spots arbitrarily chosen for analysis, 31% varied substantially in levels of expression between the sites. A number of proteins appear to be expressed only in cultures derived from one of the two anatomic sites. Interferon gamma (100 U/ml) present in the culture medium for 48 h influenced the abundance of a number of proteins in a site-specific manner. Among them, plasminogen activator inhibitor type-1 was induced three to five times in the leg cultures, whereas this same polypeptide was down-regulated in abdominal fibroblasts. A 54-kD protein was induced in interferon-treated cultures from both sites at least 50 times. It appears that fibroblasts from different regions of the integument are intrinsically distinct in terms of both their protein synthetic programs and their responses to cytokines.