The effect of lysosomal enzymes on the proliferation of aortic smooth muscle cells and fibroblasts.
The rate of 3H-thymidine incorporation and cell multiplication was investigated in aortic smooth muscle cells and WI-38 fibroblasts exposed to lysosomal enzymes isolated from liver or alveolar macrophages. It was found that cells grown in the presence of lysosomal enzymes reached higher final densities than untreated cells and the rate of 3H-thymidine incorporation was markedly increased in the enzyme-exposed cultures. The stimulation of 3H-thymidine uptake was detected both in growing and quiescent cultures of smooth muscle cells and WI-38 fibroblasts. The precursor taken up by the lysosomal enzyme treated cells was incorporated into a DN-ase susceptible material. These experiments illustrate that lysosomal enzymes, when present in low concentration in the cellular environment, can act as mitogens and may play a role in the pathogenesis of atherosclerosis.
D000818:Animals; D001013:Aorta, Thoracic; D001161:Arteriosclerosis / Q000209:etiology; D002417:Cattle; D002455:Cell Division; D002478:Cells, Cultured; D003851:Deoxyribonucleases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology*; D008247:Lysosomes / Q000201:enzymology*; D008934:Mitogens; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D013936:Thymidine / Q000378:metabolism
D008934:Mitogens; D003851:Deoxyribonucleases; D013936:Thymidine