Atherosclerotic lesions mainly form in arterial areas exposed to low shear stress (LSS), where endothelial cells express a senescent and inflammatory phenotype. Conversely, areas exposed to high shear stress (HSS) are protected from plaque development. Endothelial extracellular vesicles (EVs) have been shown to regulate inflammation and senescence, and therefore play a crucial role in vascular homeostasis. Whilst previous studies have shown links between hemodynamic forces and EV release, the effects of shear stress on the release and uptake of endothelial EVs remains elusive. We aim to decipher the interplay between these processes in endothelial cells exposed to atheroprone or atheroprotective shear stress. Confluent HUVECs were exposed to LSS or HSS for 24 h. Large and small EVs were isolated from conditioned medium by centrifugation and size exclusion chromatography. They were characterised by TEM, Western blot, tunable resistive pulse sensing, flow cytometry and proteomics. Uptake experiments were performed using fluorescently-labelled EVs and differences between groups were assessed by flow cytometry and confocal microscopy. We found that levels of large and small EVs in conditioned media were fifty and five times higher in HSS than in LSS conditions, respectively. In vivo and in vitro uptake experiments revealed greater EV incorporation by cells exposed to LSS conditions. Additionally, endothelial LSS-EVs have a greater affinity for HUVECs than HSS-EVs or EVs derived from platelets, erythrocytes and leukocytes. Proteomic analysis revealed that LSS-EVs were enriched in adhesion proteins (PECAM1, MCAM), participating in EV uptake by endothelial cells. LSS-EVs also carried mitochondrial material, which may be implicated in elevating ROS levels in recipient cells. These findings suggest that shear stress influences EV biogenesis and uptake. Given the major role of EVs and shear stress in vascular health, deciphering the relation between these processes may yield innovative strategies for the early detection and treatment of endothelial dysfunction.
© 2024 The Authors. Journal of Extracellular Vesicles published by Wiley Periodicals LLC on behalf of International Society for Extracellular Vesicles.

Atherosclerotic lesions mainly form in arterial areas exposed to low shear stress (LSS), where endothelial cells express a senescent and inflammatory phenotype. Conversely, high shear stress (HSS) has atheroprotective effects on the endothelium. Endothelial cell-derived extracellular vesicles have been shown to regulate inflammation, senescence and angiogenesis and therefore play a crucial role in vascular homeostasis and disease. While previous studies have shown links between hemodynamic forces and extracellular vesicle release, the exact consequences of shear stress on the release and uptake of endothelial EVs remains elusive. Our aim is therefore to decipher the interplay between these processes in endothelial cells exposed to atheroprone or atheroprotective shear stress. Confluent human umbilical vein endothelial cells (HUVEC) were exposed to either LSS or HSS for 24 hours. Large and small EVs were isolated from conditioned medium by sequential centrifugation and size exclusion chromatography. They were characterized by TEM, Western blot analysis of EV markers, tunable resistive pulse sensing, flow cytometry and proteomics. Uptake experiments were performed using fluorescently-labeled EVs and differences between groups were assessed by flow cytometry and confocal microscopy. We found that levels of large and small EVs in HUVEC conditioned media were fifty and five times higher in HSS than in LSS conditions, respectively. In vivo and in vitro uptake experiments revealed greater EV incorporation by cells exposed to LSS conditions compared to HSS. Additionally, endothelial LSS-EVs appeared to have a greater affinity for HUVECs than HSS-EVs or EVs derived from platelets, red blood cells, granulocytes and peripheral blood mononuclear cells. Proteomic analysis revealed that LSS-EVs were enriched in adhesion proteins such as PECAM1, MCAM, which were involved in EV uptake by endothelial cells. LSS-EVs also carried mitochondrial material, which may be involved in elevating reactive oxygen species levels in recipient cells. These findings suggest that endothelial shear stress has a significant impact during EV biogenesis and uptake. Given the major role of EVs and shear stress in vascular health, deciphering the relation between these processes may yield innovative strategies for the early detection and treatment of endothelial dysfunction.

The extracellular matrix (ECM) plays critical roles in tumor progression and metastasis. However, the contribution of ECM proteins to early metastatic onset in the peritoneal cavity remains unexplored. Here, we suggest a new route of metastasis through the interaction of integrin alpha 2 (ITGA2) with collagens enriched in the tumor coinciding with poor outcome in patients with ovarian cancer. Using multiple gene-edited cell lines and patient-derived samples, we demonstrate that ITGA2 triggers cancer cell adhesion to collagen, promotes cell migration, anoikis resistance, mesothelial clearance, and peritoneal metastasis in vitro and in vivo. Mechanistically, phosphoproteomics identify an ITGA2-dependent phosphorylation of focal adhesion kinase and mitogen-activated protein kinase pathway leading to enhanced oncogenic properties. Consequently, specific inhibition of ITGA2-mediated cancer cell-collagen interaction or targeting focal adhesion signaling may present an opportunity for therapeutic intervention of metastatic spread in ovarian cancer.
© 2020, Huang et al.

Recombinant DNA techniques are capable of introducing genetic changes into food organisms that are more predictable than those introduced through conventional breeding techniques. This review discusses whether the consumption of DNA in approved novel foods and novel food ingredients derived from genetically modified organisms (GMOs) can be regarded as being as safe as the consumption of DNA in existing foods. It concludes that DNA from GMOs is equivalent to DNA from existing food organisms that has always been consumed with human diets. Any risks associated with the consumption of DNA will remain, irrespective of its origin, because the body handles all DNA in the same way. The breakdown of DNA during food processing and passage through the gastrointestinal tract reduces the likelihood that intact genes capable of encoding foreign proteins will be transferred to gut microflora. The review does not specifically address food safety issues arising from the consumption of viable genetically modified microorganisms but it shows that the likelihood of transfer and functional integration of DNA from ingested food by gut microflora and/or human cells is minimal. Information reviewed does not indicate any safety concerns associated with the ingestion of DNA per se from GMOs resulting from the use of currently available recombinant DNA techniques in the food chain.
Copyright 2001 S. Karger AG, Basel