OBJECTIVE: We have previously shown that macrophage colony stimulating factor (M-CSF), a potent survival and mitogenic factor for monocytes/macrophages (MM), enables MM to induce vascular smooth muscle cell (VSMC) apoptosis. The killing requires the binding of MM to VSMC via Mac-1 (CD11b/CD18) on MM and intracellular adhesion molecule-1 (ICAM-1) on VSMC. We hypothesized that, in addition to Mac-1 binding, the killing process requires the activation of the Fas-death receptor pathway, which can be blocked at the level of Fas-Fas ligand interaction. METHODS AND RESULTS: Human peripheral blood monocytes and VSMC were isolated and cultured as previously described. Soluble Fas (sFas) was overexpressed in VSMC by transduction using adenovirus specifying soluble Fas (Ad3hsFas). M-CSF markedly increased the expression of ICAM-1 in VSMC, resulting in enhanced clustering of MM on the surface of VSMC (>/=3 MM per VSMC). MM, but not VSMC, expressed Fas-ligand (FasL), and VSMC apoptosis was inhibited by secretion of sFas by VSMC upon Ad3sFas transduction. CONCLUSIONS: MM and M-CSF-induced VSMC killing requires MM binding to VSMC mediated by Mac-1 and ICAM-1, and Fas-FasL interaction.
OBJECTIVE: We have previously shown that macrophage colony stimulating factor (M-CSF), a potent survival and mitogenic factor for monocytes/macrophages (MM), enables MM to induce vascular smooth muscle cell (VSMC) apoptosis. The killing requires the binding of MM to VSMC via Mac-1 (CD11b/CD18) on MM and intracellular adhesion molecule-1 (ICAM-1) on VSMC. We hypothesized that, in addition to Mac-1 binding, the killing process requires the activation of the Fas-death receptor pathway, which can be blocked at the level of Fas-Fas ligand interaction. METHODS AND RESULTS:Human peripheral blood monocytes and VSMC were isolated and cultured as previously described. Soluble Fas (sFas) was overexpressed in VSMC by transduction using adenovirus specifying soluble Fas (Ad3hsFas). M-CSF markedly increased the expression of ICAM-1 in VSMC, resulting in enhanced clustering of MM on the surface of VSMC (>/=3 MM per VSMC). MM, but not VSMC, expressed Fas-ligand (FasL), and VSMC apoptosis was inhibited by secretion of sFas by VSMC upon Ad3sFas transduction. CONCLUSIONS: MM and M-CSF-induced VSMC killing requires MM binding to VSMC mediated by Mac-1 and ICAM-1, and Fas-FasL interaction.
Authors: Joseph J Boyle; Ivy Christou; M Bilal Iqbal; Aivi T Nguyen; Viola W Y Leung; Paul C Evans; Yu Liu; Michael Johns; Paul Kirkham; Dorian O Haskard Journal: Am J Pathol Date: 2012-05-30 Impact factor: 4.307