Microparticles generated during chronic cerebral ischemia deliver proapoptotic signals to cultured endothelial cells

• Published in: Biochemical and biophysical research communications 2014-07, Vol.450 (1), p.912-917
• Main Authors: Schock, Sarah C., Edrissi, Hamidreza, Burger, Dylan, Cadonic, Robert, Hakim, Antoine, Thompson, Charlie
• Format: Article
• Language: English
• Subjects: 60 APPLIED LIFE SCIENCES; Animals; ANTIBODIES; APOPTOSIS; Apoptosis Regulatory Proteins - metabolism; BLOOD PLASMA; Brain Ischemia - metabolism; Caspase 3 - metabolism; Cell Communication; CELL CULTURES; Cell Survival; Cell-Derived Microparticles - metabolism; Cell-Derived Microparticles - pathology; Cells, Cultured; Cerebral ischemia; Chronic Disease; DOSES; ELECTRON MICROSCOPY; Endothelial Cells - metabolism; Endothelial Cells - pathology; INHIBITION; ISCHEMIA; KIDNEYS; Male; Microparticles; OXIDATION; Particle Size; RATS; Rats, Long-Evans; RECEPTORS; Receptors, TNF-Related Apoptosis-Inducing Ligand - metabolism; Receptors, Tumor Necrosis Factor - metabolism; TNF-α; TRAIL; Tumor Necrosis Factor-alpha - metabolism
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2014.06.096

•Microparticles are elevated in the plasma in a rodent model of chronic cerebral ischemia.•These microparticles initiate apoptosis in cultured cells.•Microparticles contain caspase 3 and they activate receptors for TNF-α and TRAIL. Circulating microparticles (MPs) are involved in many physiological processes and numbers are increased in a variety of cardiovascular disorders. The present aims were to characterize levels of MPs in a rodent model of chronic cerebral hypoperfusion (CCH) and to determine their signaling properties. MPs were isolated from the plasma of rats exposed to CCH and quantified by flow cytometry. When MPs were added to cultured endothelial cells or normal rat kidney cells they induced cell death in a time and dose dependent manner. Analysis of pellets by electron microscopy indicates that cell death signals are carried by particles in the range of 400nm in diameter or less. Cell death involved the activation of caspase 3 and was not a consequence of oxidative stress. Inhibition of the Fas/FasL signaling pathway also did not improve cell survival. MPs were found to contain caspase 3 and treating the MPs with a caspase 3 inhibitor significantly reduced cell death. A TNF-α receptor blocker and a TRAIL neutralizing antibody also significantly reduced cell death. Levels of circulating MPs are elevated in a rodent model of chronic cerebral ischemia. MPs with a diameter of 400nm or less activate the TNF-α and TRAIL signaling pathways and may deliver caspase 3 to cultured cells.