Directional endothelial communication by polarized extracellular vesicle release
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ABSTRACT: EVs were isolated from primary human aortic endothelial cells (ECs) (+/- IL-1b activation) grown on transwells, quantified, and analysed by miRNA transcriptomics.
Project description:EVs were isolated from primary human aortic endothelial cells (ECs) (+/- IL-1b activation), quantified, and analysed by miRNA transcriptomics and proteomics.
Project description:EVs were isolated from primary human aortic endothelial cells (ECs) (+/- IL-1b activation), quantified, and analysed by miRNA transcriptomics and proteomics. Compared to quiescent ECs, activated ECs increased EV release, with miRNA and protein cargo that were related to atherosclerosis pathways. RNA sequencing of EV-treated monocytes and vascular smooth muscle cells (VSMCs) revealed that EVs from activated ECs altered pathways that were pro-inflammatory and atherogenic.
Project description:BackgroundExtracellular vesicles (EVs) contain bioactive cargo including miRNAs and proteins that are released by cells during cell-cell communication. Endothelial cells (ECs) form the innermost lining of all blood vessels, interfacing with cells in the circulation and vascular wall. It is unknown whether ECs release EVs capable of governing recipient cells within these 2 separate compartments. Given their boundary location, we propose ECs use bidirectional release of distinct EV cargo in quiescent (healthy) and activated (atheroprone) states to communicate with cells within the circulation and blood vessel wall.MethodsEVs were isolated from primary human aortic ECs (plate and transwell grown; ±IL [interleukin]-1β activation), quantified, visualized, and analyzed by miRNA transcriptomics and proteomics. Apical and basolateral EC-EV release was determined by miRNA transfer, total internal reflection fluorescence and electron microscopy. Vascular reprogramming (RNA sequencing) and functional assays were performed on primary human monocytes or smooth muscle cells±EC-EVs.ResultsActivated ECs increased EV release, with miRNA and protein cargo related to atherosclerosis. EV-treated monocytes and smooth muscle cells revealed activated EC-EV altered pathways that were proinflammatory and atherogenic. ECs released more EVs apically, which increased with activation. Apical and basolateral EV cargo contained distinct transcriptomes and proteomes that were altered by EC activation. Notably, activated basolateral EC-EVs displayed greater changes in the EV secretome, with pathways specific to atherosclerosis. In silico analysis determined compartment-specific cargo released by the apical and basolateral surfaces of ECs can reprogram monocytes and smooth muscle cells, respectively, with functional assays and in vivo imaging supporting this concept.ConclusionsDemonstrating that ECs are capable of polarized EV cargo loading and directional EV secretion reveals a novel paradigm for endothelial communication, which may ultimately enhance the design of endothelial-based therapeutics for cardiovascular diseases such as atherosclerosis where ECs are persistently activated.
Project description:Aging significantly affects intercellular communication between vascular endothelial cells (ECs) and hematopoietic cells, leading to vascular inflammation and age-associated diseases. This study determined how senescent ECs communicate with monocytes, whether extracellular vesicles (EVs) released from senescent ECs affect monocyte functions, and investigated the potential for epigallocatechin-3-gallate (EGCG), a flavonoid in green tea, to reverse these effects. Human umbilical vein endothelial cells (HUVECs) were treated with Etoposide (10 µM, 24h) to induce senescence, followed by EGCG (100 µM, 24h) treatment to evaluate its potential as a senotherapeutic agent. The interaction between ECs and monocytes was analyzed using a co-culture system and direct treatment of monocytes with EC-derived EVs. EGCG reduced senescence-associated phenotypes in ECs, as evidenced by decreased senescence-associated (SA)-β-Gal activity and reversal of Etoposide-induced senescence markers. Monocytes co-cultured with EGCG-treated senescent ECs showed decreased pro-inflammatory responses compared to those co-cultured with untreated senescent ECs. Additionally, senescent ECs produced more EVs than non-senescent ECs. EVs from senescent ECs enhanced lipopolysaccharide (LPS)-induced pro-inflammatory activation of monocytes, whereas EVs from EGCG-treated senescent ECs mitigated this activation, maintaining monocyte activation at normal levels. Our findings reveal that EGCG confers anti-senescent effects via modulation of the senescent EC secretome (including EVs) with the capacity to modify monocyte activation. These findings suggest that EGCG could act as a senotherapeutic agent to reduce vascular inflammation related to aging.
Project description:Small extracellular vesicles (EVs) are released by cells and deliver biologically active payloads important in the intercellular signaling that coordinates the response of multiple cell types in cutaneous wound healing. Here we focus on the use of EV reporters to address cell type specificity and central questions regarding EV source cells, target cells, heterogeneity, payload, and activity using a combination of molecular approaches to address some of the barriers to translation in the use of engineered EVs. We identify a role for EVs released by resident macrophages present in adipose tissue and dermis to stimulate proliferation of overlying basal layer of keratinocytes. For these studies we use an allograft model, where donor EVs are harvested from subcutaneous implants, then purified for transplantation into the wound bed of recipient mice with a defined impaired wound healing phenotype. We demonstrate that EVs isolated from diabetic obese mice decreased keratinocyte proliferation and delayed wound closure, and that EVs loaded with specific miRNAs like miR-425-5p increased proliferation and accelerated wound closure. Utilizing a CD9-GFP reporter system, we show that fibroblasts uptake macrophage-derived EVs. In this work, we show that cell type-specific approaches can be used to unravel the biochemical activity of EVs in the complex microenvironment of the wound bed and form the basis for developing targeted pro-reparative EV payloads.
Project description:BackgroundBoth vector borne and sexual transmission of Zika virus (ZIKV) involve infection of epithelial cells in the initial stages of infection. Epithelial cells are unique in their ability to form polarized monolayers and their barrier function. Cell polarity induces an asymmetry in the epithelial monolayer, which is maintained by tight junctions and specialized sorting machinery. This differential localization can have a potential impact of virus infection. Asymmetrical distribution of a viral receptor can restrict virus entry to a particular membrane while polarized sorting can lead to a directional release of virions. The present study examined the impact of cell polarity on ZIKV infection and release.MethodsA polarized Caco-2 cell model we described previously was used to assess ZIKV infection. Transepithelial resistance (TEER) was used to assess epithelial cell polarity, and virus infection was measured by immunofluorescence microscopy and qRT-PCR. Cell permeability was measured using a fluorescein leakage assay. Statistical significance was calculated using one-way ANOVA and significance was set at p < 0.05.ResultsUsing the Caco-2 cell model for polarized epithelial cells, we report that Zika virus preferentially infects polarized cells from the apical route and is released vectorially through the basolateral route. Our data also indicates that release occurs without disruption of cell permeability.ConclusionsOur results show that ZIKV has directional infection and egress in a polarized cell system. This mechanism of directional infection may be one of the mechanisms that enables the cross the epithelial barrier effectively without a disruption in cell monolayer integrity. Elucidation of entry and release characteristics of Zika virus in polarized epithelial cells can lead to better understanding of virus dissemination in the host, and can help in developing effective therapeutic interventions.
Project description:UnlabelledBloodstream spread is a critical step in the pathogenesis of many viruses. However, mechanisms that promote viremia are not well understood. Reoviruses are neurotropic viruses that disseminate hematogenously to the central nervous system. Junctional adhesion molecule A (JAM-A) is a tight junction protein that serves as a receptor for reovirus. JAM-A is required for establishment of viremia in infected newborn mice and viral spread to sites of secondary replication. To determine how viruses gain access to the circulatory system, we examined reovirus infection of polarized human brain microvascular endothelial cells (HBMECs). Reovirus productively infects polarized HBMECs, but infection does not alter tight junction integrity. Apical infection of polarized HBMECs is more efficient than basolateral infection, which is attributable to viral engagement of sialic acid and JAM-A. Viral release occurs exclusively from the apical surface via a mechanism that is not associated with lysis or apoptosis of infected cells. These data suggest that infection of endothelial cells routes reovirus apically into the bloodstream for systemic dissemination in the host. Understanding how viruses invade the bloodstream may aid in the development of therapeutics that block this step in viral pathogenesis.ImportanceBloodstream spread of viruses within infected hosts is a critical but poorly understood step in viral disease. Reoviruses first enter the host through the oral or respiratory route and infect cells in the central nervous system. Spread of reoviruses to the brain occurs by blood or nerves, which makes reoviruses useful models for studies of systemic viral dissemination. In this study, we examined how reoviruses infect endothelial cells, which form the walls of blood vessels. We found that reovirus infection of endothelial cells allows the virus to enter blood vessels and serves as a means for the virus to reach high titers in the circulation. Understanding how reovirus is routed through endothelial cells may aid in the design of antiviral drugs that target this important step in systemic viral infections.