A physiologic three-dimensional cell culture system to investigate the role of decorin in matrix organisation and cell survival

In vivo cells exist in a three-dimensional environment generated and maintained by multiple cell-cell and cell-matrix interactions. Proteoglycans, like decorin, affect these complex interactions. Thus, we sought to investigate the role of decorin in a three-dimensional environment where the matrix was generated over time by decorin-deficient fibroblasts in the presence of l-ascorbic acid 2-phosphate. The cells were viable and proliferated in response to FGF2. Decorin was incorporated in the matrix and caused a ∼2 nm shift in the average diameter of the collagen fibrils, and the range and distribution of the fibrils became narrower and more uniform. Although there were no appreciable changes in collagen composition, we found that exogenous decorin induced the de novo synthesis of collagen I and V and cross-linked β (I). In the early phases of the three-dimensional culture, decorin reduced apoptosis. However, following the establishment of a three-dimensional matrix, the cells did not require decorin for their survival.