Fibroblast RNA and macrophage proteins (including the fibrogenic factor) in experimental silicosis.
A hypothesis is presented for the action of silica-treated macrophages on protein synthesis in fibroblasts and also a method for the isolation of silica-attached materials in lung tissue. The increased protein synthesis in the fibroblasts is due, at least partly, to an increase in mRNA. Silica prevents the suppressing "macrophage effect" of macrophage-originated ribonuclease on fibroblasts. However, under certain conditions, collagen synthesis is stimulated by silica-treated macrophage preparations to such an extent that the effect cannot be explained by the inhibition of macrophage ribonuclease alone. We therefore postulate the existence of a fibrogenic factor, which is released by the macrophages. This factor has been demonstrated and can be purified from lung homogenate of SiO2-treated rats.
D000818:Animals; D005347:Fibroblasts / Q000378:metabolism; D066298:In Vitro Techniques; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D012313:RNA / Q000378:metabolism*; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism; D012822:Silicon Dioxide / Q000378:metabolism / Q000633:toxicity; D012829:Silicosis / Q000378:metabolism*
D011506:Proteins; D012313:RNA; D012822:Silicon Dioxide; D012260:Ribonucleases