Adhesive multiplicity in the interaction of embryonic fibroblasts and myoblasts with extracellular matrices.

Abstract

Neff et al. (1982, J. Cell Biol., 95:654-666) have described a monoclonal antibody, CSAT, directed against a cell surface antigen that participates in the adhesion of skeletal muscle to extracellular matrices. We used the same antibody to compare and parse the determinants of adhesion and morphology on myogenic and fibrogenic cells. We report here that the antigen is present on skeletal and cardiac muscle and on tendon, skeletal, dermal, and cardiac fibroblasts; however, its contribution to their morphology and adhesion is different. The antibody produces large alterations in the morphology and adhesion of skeletal myoblasts and tendon fibroblasts; in contrast, its effects on the cardiac fibroblasts are not readily detected. The effects of CSAT on the other cell types, i.e., dermal and skeletal fibroblasts, cardiac muscle, 5-bromodeoxyuridine-treated skeletal muscle, lie between these extremes. The effects of CSAT on the skeletal myoblasts depends on the calcium concentration in the growth medium and on the culture age. We interpret these differential responses to CSAT as revealing differences in the adhesion of the various cells to extracel[ular matrices. This interpretation is supported by parallel studies using quantitative assays of cell-matrix adhesion. The likely origin of these adhesive differences is the progressive display of different kinds of adhesion-related molecules and their organizational complexes on increasingly adhesive cells. The antigen to which CSAT is directed is present on all of the above cells and thus appears to be a lowest common denominator of their adhesion to extracellular matrices.Adhesive differences among embryonic cells are thought to play a prominent role in directing morphogenesis (2, 32). Numerous examples of such differential adhesions have been described and evidence has been presented that relates them to morphogenic phenomena. The histotypic sorting out of embryonic cells is rationalized as reflecting the graded, differential adhesive interactions of the constituent cells (24,26,30,31). In the nervous system, the high specificity of retinotectal interactions appears to reflect the adhesive gradients generated by the retinal and tectal cells (12,24). The migration of neuronal processes to their peripheral targets is also highly specific and is hypothesized to reflect the differential affinities of the processes for extracellular substrates (7,23).Recently membrane proteins have been identified and isolated using adhesion-perturbing monoclonal antibodies whose antigens localize in the region of cell-substratum adhesions (13, 27, 28). One of these antibodies, called CSAT, is directed against an antigen that participates in the adhesion of embryonic skeletal muscle to extracellular matrices (17,18,27). T The active determinant appears to be part of an integral membrane protein complex located in the vicinity of transmembrane assemblies involved in adhesion. The identification of such adhesion-related molecules allows an investigation of their role in regulating the...

The biology of cell locomotion within three-dimensional extracellular matrix

“…Adhesion-independent migration is a controversial issue. Leukocyte migration in attachment-dependent migration models is reduced by adhesion-perturbing antibodies against i1 integrins in vitro [92,100,116,117] and in vivo [85], although never fully abolished. In 3-D collagen lattices, T lymphocytes, monocytes, and dendritic cells continue to migrate after blocking of i1 integrins as assessed by cell-tracking techniques [9,51].…”

Expression of β1 integrins changes during transformation of avian lens epithelium to mesenchyme in collagen gels

“…Both antibodies cause myoblasts to round-up in vitro (Decker et al, 1984;Greve and Gottlieb, 1982) and inhibit fibronectin-mediated adhesion and spreading of normal and transformed fibroblasts (Decker et al, 1984;Chen et al, 1985). Mouse monoclonal antibody 1-N recognizes band 3 (pl integrin) of the complex precipitated by JG22E and CSAT, but does not perturb ligand binding (Clayton Buck, personal communication).…”

Stem Cells

“…The extracellular matrix (ECM) of cardiac tissue, which is composed of a number of cells including cardiac fibroblasts, mesenchymal cells, fibronectin, and other matrix proteins [22-24], provides elasticity and mechanical strength. We have isolated several stromal cell populations from human fetal heart that are positive for CD105, CD90, and CD73, but negative for CD34 and CD45, which is consistent with the phenotype of BM-derived MSCs.…”