Differential effects of ethnic microparticles on endothelial cell death and apoptosis
Individuals of South Asian and Black African origin are at a greater risk of diabetes, cancer and cardiovascular disease (CVD). Microparticles (MP), biologically active nanoparticles shed from cells, are novel markers of inflammation and might contribute to the pathogenicity of disease. The aim of this study is to assess the phenotypic differences of ethnic MP and their effects on endothelial cells in vitro. In this pilot study, MP were isolated from blood taken from healthy volunteers of different ethnic groups (White n=6, Black n=7, Asian n=4; there were no differences in age or BMI of ethnic groups), and stained with AnV for PS-MP, CD142 (Tissue Factor) or CD295 (LeptinR); MP were also stimulated with 100ng/ml PMA and stained with DCFH-DA to assay ROS activity. Endothelial cell line EA.hy926 were seeded to confluence in 48-well plates, MP in media were added for 48 hours at 37⁰C 5% CO2. Supernatant MP were removed, and EA.hy926 were stained with AnV-PI for apoptosis. All MP and EA.hy926 were analysed using flow cytometry. Circulating Asian MP stained significantly greater for pro-coagulant PS-MP (5.09±0.38% vs White 2.98±0.79%, Black 3.53±0.58%, P<0.03), pro-coagulant CD142-MP (11.57±1.10±0.38% vs White 8.24±1.23%, Black 7.56±0.40%, P<0.01) and tumourigenic CD295-MP (52.41±2.73±0.38% vs White 46.42±2.82%, Black 45.15±2.76%, P<0.01) than both White and Black MP. Black MP had a reduced, but not significant, change in ROS DCFH-DA-signal upon stimulation with PMA. Interestingly, Asian MP induced a significantly greater proportion of smaller MP released from EA.hy926 cells (56.70±5.02% vs Black 39.70±3.10%, P<0.05), and greater apoptosis of EA.hy926 (19.80±1.97% vs Black 15.09±1.31%, P<0.05). Black MP induced significantly greater EA.hy926 death (1.07±0.15% vs White 0.92±0.08, P<0.005). Our results suggest that the increased pro-coagulant and tumourigenic nature of Asian MP might affect disease pathology. Some of these effects include apoptosis and release of small MP from EA.hy926 in vitro, but the clinical significance of these findings is unclear. Black MP have reduced ROS upon stimulation, possibly due to higher baseline ROS levels and oxidative anergy; these MP also induce greater death in EA.hy926. These results might indicate a role of MP in the increased incidence of CVD in Black individuals. Further work on the pathophysiological role of ethnic MP is required to assess these initial findings.
Citation : Pritchard, C., Henshaw, M., Hussain, A., Yousaf, N.,Akubueze, A., Martin, N. (2018) Differential effects of ethnic microparticles on endothelial cell death and apoptosis. Midlands Innovation Flow Group
Peer Reviewed : No