Extracellular Vesicles Activate a CD36-Dependent Signaling Pathway to Inhibit Microvascular Endothelial Cell Migration and Tube Formation

Abstract

Objective Literature on the effect of cell-derived extracellular vesicles (EV), ≤1μm vesicles shed from various cell types during activation or apoptosis, on microvascular endothelial cell (MVEC) signaling is conflicting. Thrombospondin-1 and related proteins induce anti-angiogenic signals in MVEC via CD36. CD36 binds EV via phosphatidylserine (PS) exposed on their surface but the effects of this interaction on MVEC functions are not known. We hypothesized that EV would inhibit angiogenic MVEC functions via CD36. Approach and Results EV generated in vitro from various cell types or isolated from plasma inhibited MVEC tube formation in in vitro matrigel assays and EC migration in Boyden chamber assays. Exosomes derived from the same cells did not have inhibitory activity. Inhibition of migration required EC expression of CD36. In mouse in vivo matrigel plug assays EV inhibited cell migration into matrigel plugs in wild type but not in cd36 null animals. Annexin V, an anionic phospholipid binding protein, when incubated with EV partially reversed inhibition of migration, suggesting a PS-dependent effect. EV exposure induced reactive oxygen species (ROS) generation in MVEC in a NADPH oxidase and Src family kinase dependent manner and their inhibition by apocynin and PP2, respectively, partially reversed the EV-mediated inhibition of migration. Annexin V partially reversed EV-induced ROS generation in murine CD36 cDNA transfected HVUEC but not in CD36 negative HUVEC. Conclusions These studies establish a general inhibitory effect of EV on EC pro-angiogenic responses and identify a CD36-mediated mechanistic pathway through which EV inhibit MVEC migration and tube formation.

Monocyte exosomes induce adhesion molecules and cytokinesviaactivation of NF‐κB in endothelial cells

“…At present, less than a handful of studies have been published on the effect of monocyte Exos on target cells. In most of these studies, extracellular vesicles, including microparticles, from THP1 acute monocytic leukemia cells were used (26)(27)(28)(29). Microparticles are distinct from Exos, in that they are larger and originate from a different cellular compartment.…”

Down‐regulation of exosomal miR‐106b‐5p derived from cholesteatoma perimatrix fibroblasts promotes angiogenesis in endothelial cells by overexpression of Angiopoietin 2

“…Several studies have demonstrated that exosomal miRNA can modulate angiogenesis through targeting different mRNAs (van Balkom et al, ; Kang et al, ; Liang et al, ; Ramakrishnan et al, ). Exosomal miR‐126‐3p from CD34 + stem cells (Mathiyalagan et al, ), exosomal miR‐125a from adipose‐derived MSCs (Liang et al, ), exosomal miR‐23a from hypoxic lung cells (Hsu et al, ), exosomal miR‐17‐92 cluster and miR‐21 from leukaemia cells (Umezu et al, ), and exosomal miR‐21 from glioma stem cell (Sun et al, ) promote endothelial cell viability, proliferation, migration, or tube formation.…”

Extracellular vesicles and microvascular pathology: Decoding the active dialogue

“…In contrast, Ramakrishnan et al reported that EV isolated from various sources in vitro , including endothelial cells, circulating red blood cells and tumor cells, as well as circulating EV isolated from healthy humans and subjects with vasculitis, inhibited microvascular endothelial cell migration and tube‐like structure formation. They further demonstrated that EV from different sources inhibited the endothelial cell pro‐angiogenic activity due to the interaction of PS on EV membranes with CD36 on microvascular endothelial cells, involving NADPH and Fyn kinase–mediated ROS generation . In a more recent study, the angiogenic effect of exosomes derived from two oral squamous cell carcinoma cell lines (SCC15 and HSC3) was found to increase HUVEC migration and tube formation .…”

“…69 Kucharzewska and colleagues reported that hypoxic exosomes ac- to the interaction of PS on EV membranes with CD36 on microvascular endothelial cells, involving NADPH and Fyn kinase-mediated ROS generation. 72 In a more recent study, the angiogenic effect of exosomes derived from two oral squamous cell carcinoma cell lines (SCC15 and HSC3) was found to increase HUVEC migration and tube formation. 73 Thus, many different EV proteins, including but not limited to CD97, 74 the heparin-binding factor midkine, 75 and annexin II, 76 have been shown to support angiogenesis in cancer models by affecting different mechanisms.…”