OBJECTIVE: T cell-induced cytotoxicity, of which granzyme B is a key mediator, is believed to contribute to the pathogenesis of inflammatory vascular diseases. In this report, we investigate the mechanism of granzyme B-induced smooth muscle cell (SMC) death. METHODS AND RESULTS: The addition of purified granzyme B alone to cultured SMCs caused a significant reduction in cell viability. Chromatin condensation, phosphatidylserine externalization, and membrane blebbing were observed, indicating that the mechanism of granzyme B-induced SMC death was through apoptosis. Activated splenocytes from perforin-knockout mice induced SMC death through a granzyme B-mediated pathway. Inhibition of the proteolytic activities of caspases and granzyme B prevented granzyme B-induced SMC death, whereas attenuation of granzyme B internalization with mannose-6-phosphate (M6P) did not. Further, granzyme B induced the cleavage of several SMC extracellular proteins, including fibronectin, and reduced focal adhesion kinase phosphorylation. CONCLUSIONS: These results indicate that granzyme B can induce apoptosis of SMCs in the absence of perforin by cleaving extracellular proteins, such as fibronectin.
OBJECTIVE: T cell-induced cytotoxicity, of which granzyme B is a key mediator, is believed to contribute to the pathogenesis of inflammatory vascular diseases. In this report, we investigate the mechanism of granzyme B-induced smooth muscle cell (SMC) death. METHODS AND RESULTS: The addition of purified granzyme B alone to cultured SMCs caused a significant reduction in cell viability. Chromatin condensation, phosphatidylserine externalization, and membrane blebbing were observed, indicating that the mechanism of granzyme B-induced SMC death was through apoptosis. Activated splenocytes from perforin-knockout mice induced SMC death through a granzyme B-mediated pathway. Inhibition of the proteolytic activities of caspases and granzyme B prevented granzyme B-induced SMC death, whereas attenuation of granzyme B internalization with mannose-6-phosphate (M6P) did not. Further, granzyme B induced the cleavage of several SMC extracellular proteins, including fibronectin, and reduced focal adhesion kinase phosphorylation. CONCLUSIONS: These results indicate that granzyme B can induce apoptosis of SMCs in the absence of perforin by cleaving extracellular proteins, such as fibronectin.
Authors: Janet E McElhaney; Xin Zhou; H Keipp Talbot; Ernst Soethout; R Chris Bleackley; David J Granville; Graham Pawelec Journal: Vaccine Date: 2012-01-27 Impact factor: 3.641
Authors: Robert J Freishtat; Joanne Natale; Angela S Benton; Joanna Cohen; Matthew Sharron; Andrew A Wiles; Wai-Man Ngor; Bahar Mojgani; Margaret Bradbury; Andrew Degnan; Reecha Sachdeva; Lindsay M Debiase; Svetlana Ghimbovschi; Matthew Chow; Clarice Bunag; Ervand Kristosturyan; Eric P Hoffman Journal: Am J Respir Crit Care Med Date: 2009-01-08 Impact factor: 21.405
Authors: Ciara M Chamberlain; Lisa S Ang; Wendy A Boivin; Dawn M Cooper; Sarah J Williams; Hongyan Zhao; Alon Hendel; Maggie Folkesson; Jesper Swedenborg; Michael F Allard; Bruce M McManus; David J Granville Journal: Am J Pathol Date: 2009-12-24 Impact factor: 4.307