Secreted midbody remnants are a class of extracellular vesicles molecularly distinct from exosomes and microparticles

Abstract

During the final stages of cell division, newly-formed daughter cells remain connected by a thin intercellular bridge containing the midbody (MB), a microtubule-rich organelle responsible for cytokinetic abscission. Following cell division the MB is asymmetrically inherited by one daughter cell where it persists as a midbody remnant (MB-R). Accumulating evidence shows MB-Rs are secreted (sMB-Rs) into the extracellular medium and engulfed by neighbouring non-sister cells. While much is known about intracellular MB-Rs, sMB-Rs are poorly understood. Here, we report the large-scale purification and biochemical characterisation of sMB-Rs released from colon cancer cells, including profiling of their proteome using mass spectrometry. We show sMB-Rs are an abundant class of membrane-encapsulated extracellular vesicle (200-600 nm) enriched in core cytokinetic proteins and molecularly distinct from exosomes and microparticles. Functional dissection of sMB-Rs demonstrated that they are engulfed by, and accumulate in, quiescent fibroblasts where they promote cellular transformation and an invasive phenotype.

Impact of chemically defined culture media formulations on extracellular vesicle production by amniotic epithelial cells

“…Transmission electron microscopy revealed that Evs were intact, spherical in morphology (Figure S2). Single particle analysis revealed that all EV samples were positive for CD9, CD81 and CD63 markers, consistent with previous reports [16,17,60,61]. All of the CD9 + , CD81 + , and CD63 + hAEC-Evs were 50-150 nm in size (Figure S3, Tables S1 and S2).…”

“…Importantly, EVs traffic their complex molecular cargo in a bidirectional manner, direct their cargoes to specific cell types, and upon uptake, the capacity to induce phenotypic change [13][14][15]. There is now growing awareness that predominant EV subtypes can be further stratified into distinct subtypes [6,[16][17][18].…”

Cancer stem cell marker DCLK1 reprograms small extracellular vesicles toward migratory phenotype in gastric cancer cells

“…Extracellular vesicles (EVs) are secreted lipid-encapsulated vesicles representing an active element of the cell secretome [55]. EVs include plasma membrane-derived large EVs (termed microvesicles, 100-1500 nm size) [56][57][58][59], endosomal-derived small EVs (termed exosomes, 30-200 nm size) [58][59][60][61], midbody remnants (200-600 nm) [62,63] and exomeres (∼30 nm size) [64,65], all are well-established mediators of cancer pathology [66][67][68]. Even though exosomes and microvesicles have different biological origin, their sizes and biomarkers overlap [58,59,[69][70][71][72], as such we used the consensus MISEV guidelines to term these EVs as either large or small EVs [68].…”

“…Andromeda [62,[94][95][96][97]. Tandem mass spectra were searched against Homo sapiens (human) reference proteome (74,811 entries, downloaded 1-2020) supplemented with common contaminants.…”

“…The endosomal EVs are smaller (30-200 nm) than plasma membrane EVs (100-1500 nm) and therefore more likely to end up in the sEV fraction. In addition, the lEV fraction consists of a heterogeneous pool of EVs (different exosome types, microvesicles) [62,71] and had approximately 2.5 Log 2 fold lower yield (AUC) (Figure S1G), hence only the composition of sEVs was analyzed by mass spectrometry. S2A, Table S1).…”