THE A10 CELL-LINE - A MODEL FOR NEONATAL, NEOINTIMAL, OR DIFFERENTIATED VASCULAR SMOOTH-MUSCLE CELLS

Objectives: The A10 cell line was derived from the thoracic aorta of e mbryonic rat and is a commonly used model of vascular smooth muscle ce lls (VSMC). Despite its wide use this cell line has not been well char acterized. This is especially important in light of recent evidence of phenotypically distinct cell populations isolated from rat vascular t issue. Therefore, the present study was undertaken to confirm the VSMC nature of A10 cells and to investigate whether these cells particular ly resemble adult, neonatal, or neointimal rat VSMC. Methods: A variet y of defining characteristics were used that included immunofluorescen t analysis for smooth muscle alpha-actin, smooth and non-muscle myosin heavy chains, desmin and vimentin; Western analysis for smooth muscle and non-muscle myosin heavy chains; mRNA analysis for smooth muscle m yosin heavy chain, calponin, SM22 alpha, tropoelastin and PDGF-B pepti de: and functional assays of cell migration, proliferation and agonist induced intracellular Ca transients. Results: A10 cells expressed smo oth muscle alpha-actin, SM22 alpha, smooth muscle calponin and vimenti n, characteristic of in vivo rat VSMCs: however they also resembled de -differentiated smooth muscle cells in that they expressed non-muscle myosin rather than smooth muscle myosin heavy chain. A10 cells resembl ed cultured rat neonatal smooth muscle cells (''pup cells'') in that t hey had an epithelioid shape and lacked functional PDGF-alpha receptor s; however they did not express PDGF-B mRNA or proliferate in low seru m containing medium as do neonatal cells. A10 cells had several charac teristics in common with neointimal cells including the expression of alpha-actin, vimentin, and non-muscle myosin and the lack of expressio n of PDGF-B mRNA as well as the ability to migrate in response to PDGF -BB. Conclusion: In conclusion, A10 cells are nondifferentiated VSMC t hat differ from neonatal but bear significant resemblance to neointima l cells. (C) 1997 Elsevier Science B.V.