Modulation of Fibroblast Growth and Glycosaminoglycan Synthesis by Interleukin-1

Abstract

Cellular response to inflammatory mediators is central to the regulation of new scar tissue formation. Fibroblasts derived from normal dermis and from 14-day old skin wound granulation tissue were compared with regard to production of non-collagenous extracellular matrix and response to interleukin-1 (IL-1). Following a serum-free 48 hour labeling with [³H]-glucosamine, the cellular, pericellular and medium fractions from the two cell types were collected, precipitated with cetylpyridinium chloride (CPC), and analyzed by cellulose acetate electrophoresis. In addition, susceptibility of precipitates to the polysaccharidases Streptomyces hyaluronidase and chondroitinase ABC was determined. Labeled conditioned medium from both cell types contained dermatan sulfate (DS) and hyaluronate (HA), although the relative amounts of these glycosaminoglycans (GAGs) were different. Medium from normal dermal fibroblasts contained more DS than HA, while 14-day granulation tissue culture medium contained a proportionately larger amount of HA. The amount of HA in the medium fraction of normal dermal fibroblasts was increased approximately 10-fold in the presence of 5 U/ml IL-1, while HA in the medium of wound-derived fibroblasts was quantitatively unaffected by addition of the mediator. Pericellular GAG consisted of heparan sulfate (HS) and chondroitin sulfate (CS), with no observable differences between the two cell types and no effect of IL-1 on this profile for either cell type. Conditioned medium from both cell types contained IL-1 activity (measured by thymocyte proliferation assay), with medium from 14-day granulation tissue fibroblasts containing 10-fold higher activity than normal dermal fibroblast medium.