Extracellular Vesicles Facilitate Large-Scale, Homogenizing Dynamic Exchange of Proteins and RNA Among Cultured Chinese Hamster Ovary (CHO) and Human Cells

Abstract

Cells in culture are viewed as unique individuals in a large population communicating through extracellular molecules and, more recently extracellular vesicles (EVs). Our data here paints a different picture: the homogenizing effect of large-scale exchange of cellular material through EVs. We show that Chinese Hamster Ovary (CHO) cells dynamically produce and uptake EVs, to exchange proteins and RNAs at large-scale. To visualize the dynamic production and cellular uptake of EVs, we used correlative confocal microscopy and scanning electron microscopy, as well as flow cytometry to interrogate labeled cells. We employed cells expressing fluorescent proteins (GFP, miRFP703) and tagged cells with protein and RNA dyes. Flow cytometry was used to quantify the exchange of cellular RNA between cells through EVs. This EV-mediated dynamic exchange observed in CHO cultures was also observed in cultures of the human CHRF-288-11 cell line and of primary human hematopoietic stem and progenitor cells. This study demonstrates an underappreciated native cell communication and protein/RNA exchange mechanism mediated by EVs spanning cell type and lines, suggesting the proximity of cells in normal and tumor tissues may also result in prolific cellular exchange. This exchange would be expected to homogenize the cell-population cytoplasm and dynamically regulate cell proliferation and cellular state.