The role of extracellular matrix in the morphogenesis and differentiation of salivary glands.

The processes of morphogenesis and cytodifferentiation are partially linked, independently regulated processes. The full expression of both processes is modulated or controlled, at least in part, by components of the extracellular matrix. This paper reviews the body of work that demonstrates a role for epithelial-mesenchymal interactions and various extracellular matrix molecules in the induction, control, and maintenance of salivary gland morphogenesis and cytodifferentiation. In addition, new, preliminary information which further elucidates the role of laminin and type IV collagen in the processes of morphogenesis and cytodifferentiation is presented. With regard to the role of extracellular matrix molecules in the regulation of salivary gland morphogenesis and cytodifferentiation, it appears that types I, III, and IV collagen, laminin, and chondroitin sulfate proteoglycan play roles in the control of glandular morphogenesis. With the exception of type IV collagen, these molecules do not appear to be involved in the regulation of cytodifferentiation of salivary gland secretory cells. On the other hand, of the extracellular matrix molecules tested so far, only type IV collagen appears to play a role in the regulation of salivary gland secretory cell differentiation.