Modulation of human mesangial cell behaviour by extracellular matrix components—the possible role of interstitial type III collagen

SUMMARY We have investigated the effects of various extracellular matrix (ECM) components on the behaviour of human mesangial cells (HMC) in u gel culture system using a modified MTT assay method. When cultured on u reconstituted basement membrane. Matrigel (M gel), HMC aggregated and formed isolated colonies initially, then extended an array of cell processes to form a dendritic network structure and proliferated very slowly as the culture period progressed. On type I colIagen gel (Cl gel), however. HMC developed elongated bipoIar shapes, migrated into the gel. and showed rapid cell growth. Next, separate ECM components, such as type III and IV colIagens. Iaminin. heparm and heparan sulphate, were incorporated into CI gel and HMC proliferation was assessed. Although attachment of HMC to each gel did not differ significantly. HMC proliferation was inhibited markedly on gels containing type III colIagen, heparin and heparan sulphate: type IV colIagen suppressed HMC proliferation slightly; and Iaminin had no significant effect. These data suggest that interstitial type I and III colIagcns. which arc often observed in diseased glomcruli. as well as the basement membrane components, may pIay important roles in the reguIation of HMC proliferation under pathophysiological conditions in vivo . We conclude that HMC behaviour is affected by the surrounding ECM constituents, which appear to function as a refined moduIator.