THE EXTRACELLULAR-MATRIX - FROM SUPPORTIN G TISSUE TO CYTOKINES REGULATION

Extracellular matrix is a polymorphic structure composed of at least t hirty molecules (collagens, glycoproteins, elastin, and proteoglycans) associated in a complex network. This insoluble structured framework ensures tissue cohesiveness, and allows cells to adhere, migrate and i nteract. Together with cytokines extracellular matrix is also involved in the control of various aspects of cell activities. Cytokines media te cell to cell communication. Their broad effect result from their pl eiotropic and overlapping activities. Once secreted, these molecules d iffuse between cells - i.e. accross extracellular matrix - to reach th eir target cells. An increasing number of cytokines are now known to b ind to the extracellular matrix. These interactions change the availab ility of cytokines on effector cells, activate some growth factors, lo calize and/or increase the duration of the expected effect. Matrix-cyt okines interactions are a new field of investigation which has changed our view on extracellular matrix. First considered as a supporting ti ssue, extracellular matrix appears now to be critically involved in th e regulation of cytokine activities.