Laminin is a high molecular weight glycoprotein usually associated with tissue basement membranes. This molecule may be involved in the processes of wound healing, tissue regeneration and embryogenesis. Laminin promotes cell adhesion to basement membrane collagen. This is mediated via specific cell surface receptors which have been shown to be expressed on endothelial cells, epithelial cells, malignant tumor cells, granulocytes, monocytes and macrophages, and even various microorganisms. Much like fibronectin, laminin or its enzymatic fragments may also be chemotactic for some of the cells bearing specific laminin receptors and thus promote accumulation of these cells at sites of inflammation. This investigation will study whether laminin plays a role in either the degradative or regenerative processes involved in periodontal disease as a model of nonspecific inflammation. This proposal will focus on whether cells from periodontal tissues express cell surface laminin and/or specific receptors for laminin. This will include a study of crevicular epithelium as well as isolated periodontal ligament cells. We will examine whether laminin can promote the attachment and growth of periodontal tissues in vitro. We will determine whether exogenous laminin can influence the interactions between inflammatory macrophages and periodontal tissue including promoting cell-cell binding or activation of macrophage cytostatic or cytolytic effects on periodontal tissue. We will also study whether can promote the interaction of macrophages with extracellular matrix generated by periodontal tissue in vitro and determine whether this will lead to degradation of this matrix in vitro. In addition, we will examine whether microorganisms associated with periodontal disease display cell surface receptors for laminin and whether exogenous laminin can enhance the phagocytic uptake of these organisms by inflammatory macrophages. Thus, this investigation should enable us to begin to characterize the role of laminin in periodontal disease and provide us new insights into the biology of this disease.
