INTERACTION OF TYPE IV COLLAGEN AGGREGATES WITH CELLS

摘要

Cell function is regulated through cytokines, cell-to-cell interactions, and cell-to-matrix interactions. Collagen proteins comprise tissue skeletal structures and influence cell functions. More than twenty types of collagen molecules are now known. The isolated type Ⅰ collagen reconstitutes into banded fibrils, reminiscent of the collagen fibrils in vivo. Reconstituted type Ⅰ collagen fibrils are utilized to form tissue-like structures including bone or dermis together with -osteoblasts or dermal fibroblasts. Thus a new issue emerges whether the combination of type Ⅰ collagen aggregates with the cells can be extended to other collagen types and cells. The cells are in contact with various extracellular matrix (ECM). Figure 1 is a proposed tissue model with ECM represented by the types of collagen in abundance together with differentiated cells. More than two types of cells are in contact with type Ⅳ collagen aggregates in vivo. Endothelial cells and epithelial cells form cell sheet underneath basement membrane, whereas smooth muscle cells and smooth muscle-related cells are surrounded by type Ⅳ collagen aggregates.