Proteolytic enzymes and arachidonic acid metabolites produced by MRC-5 cells on various microcarrier substrates

Human diploid fibroblasts were cultured on microcarriers made from DEAE-dextran, denatured collagen, DEAE-dextran linked to denatured collagen, and glass. Cells grown on these four substrates were examined for the production of proteolytic enzymes and arachidonic acid metabolites. Culture fluids from cells grown on the DEAE-dextran microcarriers contained the highest amounts of proteolytic enzyme activity. Both plasminogen-independent and plasminogen-dependent fibrinolytic activities were present and the plasminogen-dependent activity seemed to result from the presence of both urokinase and tissue plasminogen activator. Culture fluid from the cells grown on the glass microcarriers contained the least amount of protease activity, and nearly all of the plasminogen-activator activity seemed to be of the urokinase type. Protease activity in the culture fluids of cells grown on the other two substrates were intermediate. With regard to arachidonic acid metabolites, cells grown on the DEAE-dextran microcarriers produced the highest amounts of cyclooxygenase products but very low levels of lipoxygenase metabolites. Cells grown on the other three substrates produced comparable amounts of various cyclooxygenase products (lower than that produced by cells on the DEAE-dextran substrate). Cells grown on the glass microcarriers also produced detectable amounts of two lipoxygenase metabolites--leukotriene B4 and leukotriene C4. Inasmuch as both proteolytic enzymes and arachidonic acid metabolites regulate basic cell properties, the differential amounts of these metabolites observed in the culture fluids on the various substrates may contribute to the biological differences that exist on these substrates.