Penetration of macrophage ribonuclease into fibroblasts and the effects on nucleic acid and collagen metabolism.
RNAase isolated from macrophage culture medium was labelled with 3H-acetic anhydride. The acetylation density of 1.8 acetyl residues/10(4) dalton RNAase was achieved. After just 5 mins' incubation of granulation-tissue slices with 3H-Ac-RNAase, the enzyme had entered fibroblasts, and after 20 min there was only slight increase of the radioactivity. After 1 h incubation 32% of the ingested RNAse was in the nuclei, 23% in the cytosol and about 2% in RER. After the same period of incubation with 3H-Ac-RNAase, 47% of nuclear RNA of the fibroblasts was lost, as compared with the control incubation, and the amount of cytosol RNA increased by about 40%. During a 3-h incubation, in low concentrations, the biologically active macrophage RNAase stimulated. 3H-thymidine incorporation into DNA of proliferative granulation-tissue slices. Thus it was concluded that the fibrogenic effect of the macrophage RNAase on the granulation-tissue fibroblasts takes place through the RNA metabolism and the main target of the enzyme in the fibroblasts is the nuclear RNA.
D000107:Acetylation; D000818:Animals; D002463:Cell Membrane Permeability; D003094:Collagen / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D006097:Granulation Tissue / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology*; D012313:RNA / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012260:Ribonucleases / Q000378:metabolism*
D012313:RNA; D003094:Collagen; D004247:DNA; D012260:Ribonucleases