Preferential uptake of SARS-CoV-2 by pericytes potentiates vascular damage and permeability in an organoid model of the microvasculature

Abstract

Aims Thrombotic complications and vasculopathy have been extensively associated with severe COVID-19 infection, however the mechanisms inducing endotheliitis and the disruption of endothelial integrity in the microcirculation are poorly understood. We hypothesized that within the vessel wall, pericytes preferentially take up viral particles and mediate the subsequent loss of vascular integrity. Methods and Results Immunofluorescence of post-mortem patient sections were used to assess pathophysiological aspects of COVID19 infection. The effects of COVID-19 on the microvasculature were assessed using a vascular organoid model exposed to live viral particles or recombinant viral antigens. We find increased expression of the viral entry receptor ACE2 on pericytes when compared to vascular endothelium, and a reduction in the expression of the junctional protein CD144, as well as increased cell death, upon treatment with both live virus and/or viral antigens. We observe a dysregulation of genes implicated in vascular permeability including NOTCH3, angiopoietin-2 and TEK. Activation of vascular organoids with IL-1β did not have an additive effect on vascular permeability. Spike antigen was detected in some patients’ lung pericytes, which was associated with a decrease in CD144 expression and increased platelet recruitment and VWF deposition in the capillaries of these patients, with thrombi in large vessels rich in VWF and fibrin. Conclusions Together our data indicates that direct viral exposure to the microvasculature modelled by organoid infection and viral antigen treatment result in pericyte infection, detachment, damage and cell death, disrupting pericyte-endothelial cell crosstalk and increasing microvascular endothelial permeability, which can promote thrombotic and bleeding complications in the microcirculation. Translational Perspective Endotheliitis is a serious complication of severe COVID-19 patients which remains poorly understood. We identify a pericyte mediated mechanism by which the vasculature becomes compromised, contributing to thrombotic complications, highlighting important avenues for the development of therapies.

Severity of SARS-CoV-2 infection is associated with high numbers of alveolar mast cells and their degranulation

“…Controls (n = 3) were individuals died from non-COVID-19-related reasons. Detailed information about both patient and control cohorts can be found in ( 24 ). Patient lung damage was quantified by a semi-quantitative scale for the evaluation of lesion volume in lungs based on a chest CT scan, applied according to the national guidelines ( 25 , 26 ) as follows: chest CT grade 0 (no low abnormalities on the chest CT), chest CT grade 1 (25% of the lungs were affected), chest CT grade 2 (50% of the lungs were affected), chest CT grade 3 (75% of the lungs were affected), chest CT grade 4 (100% of the lungs were affected).…”

SARS-CoV-2 infection predicts larger infarct volume in patients with acute ischemic stroke

“…In addition, vWF acts as a carrier protein for FVIII in plasma, protecting it from proteolytic degradation ( 23 ). SARS-CoV-2 or SP per se can directly or through a pericyte-mediated mechanism ( 2 ), activate endothelium cells or endothelialitis can be secondary to systemic inflammation ( 2 , 3 ). In this regard, we have found a marked increase of fibrinogen levels in the COVID-19 patient group compared to AIS patients without COVID-19, whereas D-dimer levels were similar in both groups.…”

“…Hypercoagulation and microthrombosis represent the typical features of Coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) ( 1 ). The pathogenic mechanisms are not yet fully understood, but multiple pathways are involved, including endothelialitis, endothelium dysfunction due to a direct ( 1 ) or pericyte-mediated ( 2 ) virus infection, a hyper-inflammatory state (“cytokine storm”), neutrophil activation and neutrophil extracellular traps (NETs) formation that trigger thrombosis in a complex phenomenon known as “thromboinflammation” ( 1 , 3 , 4 ). SARS-CoV-2 infection is also associated with platelet hyperactivity with increased platelet-platelet and platelet-leukocyte interactions ( 5 ).…”

Blood Coagulation and Beyond: Position Paper from the Fourth Maastricht Consensus Conference on Thrombosis

“…During the SARS-CoV-2 pandemic, organoid models their utility in investigating poorly understood aspects of disease pathology. Our own work using microvascular organoid models demonstrated an important role of pericyte mediated viral uptake in the loss of vascular integrity contributing to thrombosis in severe COVID-19 infection (205). More recently, a vascularised bone marrow organoid was developed and validated which faithfully recapitulates key features of the myelopoietic central bone marrow.…”