Effect of elevated temperature on the intracellular degradation of different collagen types

The intracellular degradation of newly synthesized collagen of types I, II and IV was studied under cell culture conditions at normal and elevated body temperatures. The degradation of type I procollagen was studied in both human skin and chicken tendon fibroblasts, type II procollagen in chicken sternal chondrocytes and type IV procollagen in a human tumor cell line (HT-1080). To avoid the effect of the different temperatures on isotope penetration and protein synthesis, the cells were pulsed at 37 degrees C. The degradation of the newly synthesized procollagen was then followed during the chase period at 37 degrees C and at different temperatures slightly above the melting temperature of type I procollagen. Degradation was clearly increased in the human skin fibroblasts when the temperature was raised to 41 degrees C, whereas the result in the chicken tendon fibroblasts at 43 degrees C was not as dramatic. The extent of degradation in chicken chondrocytes was resistant to changes in temperature, whereas that in the HT-1080 cells was clearly increased when the incubation temperature was raised to 43 degrees C.