Human red blood cells release microvesicles with distinct sizes and protein composition that alter neutrophil phagocytosis

Abstract

Extracellular vesicles (EVs) are membrane‐bound structures released by cells and tissues into biofluids, involved in cell‐cell communication. In humans, circulating red blood cells (RBCs), represent the most common cell‐type in the body, generating daily large numbers of microvesicles. In vitro, RBC vesiculation can be mimicked by stimulating RBCs with calcium ionophores, such as ionomycin and A23187. The fate of microvesicles released during in vivo aging of RBCs and their interactions with circulating cells is hitherto unknown. Using SEC plus DEG isolation methods, we have found that human RBCs generate microvesicles with two distinct sizes, densities and protein composition, identified by flow cytometry, and MRPS, and further validated by immune TEM. Furthermore, proteomic analysis revealed that RBC‐derived microvesicles (RBC‐MVs) are enriched in proteins with important functions in ion channel regulation, calcium homeostasis and vesicular transport, such as of sorcin, stomatin, annexin A7 and RAB proteins. Cryo‐electron microscopy identified two separate pathways of RBC‐MV‐neutrophil interaction, direct fusion with the plasma membrane and internalization, respectively. Functionally, RBC‐MVs decrease neutrophil ability to phagocytose Escherichia coli but do not affect their survival at 24 h. This work brings new insights regarding the complexity of the RBC‐MVs biogenesis, as well as their possible role in circulation.

Erythrocyte Vulnerability to Airborne Nanopollutants

“…From the morphological findings, the sheading of extracellular vesicles is a key observation. It has been reported that erythrocyte extracellular vesicles can alter neutrophil’s phagocytic behavior depending on their size and content [ 74 ]. Extracellular nanovesicles released by human erythrocytes have been considered to play different roles in physiological, pathological, and even immune processes; their formation has been linked to intracellular calcium level increases, ATP depletion, or oxidative stress conditions [ 69 ].…”

Comprehensive Phenotyping of Extracellular Vesicles in Blood of Healthy Humans – Insights into Cellular Origin and Biological Variability

“…To estimate the relative abundance of circulating EV subsets with respect to their cell origin, we used established markers for the immunophenotyping by flow cytometry (Kalina et al 2019;Grant et al 2021;de Oliveira et al 2023;Berckmans et al 2019;Spurgeon and Frelinger 2022). We designated CD235a+ subsets as erythrocyte EVs, CD41+ and PAC1+ subsets as platelet EVs, and CD61+, CD31+, and CD62P+ subsets as originating from platelets or endothelial cells.…”