Flow-Mediated Susceptibility and Molecular Response of Cerebral Endothelia to SARS-CoV-2 Infection

Abstract

Background and Purpose: Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is associated with an increased rate of cerebrovascular events including ischemic stroke and intracerebral hemorrhage. The mechanisms underlying cerebral endothelial susceptibility and response to SARS-CoV-2 are unknown yet critical to understanding the association of SARS-CoV-2 infection with cerebrovascular events. Methods: Endothelial cells were isolated from human brain and analyzed by RNA sequencing. Human umbilical vein and human brain microvascular cells were used in both monolayer culture and endothelialized within a 3-dimensional printed vascular model of the middle cerebral artery. Gene expression levels were measured by quantitative polymerase chain reaction and direct RNA hybridization. Recombinant SARS-CoV-2 S protein and S protein–containing liposomes were used to measure endothelial binding by immunocytochemistry. Results: ACE2 (angiotensin-converting enzyme-2) mRNA levels were low in human brain and monolayer endothelial cell culture. Within the 3-dimensional printed vascular model, ACE2 gene expression and protein levels were progressively increased by vessel size and flow rates. SARS-CoV-2 S protein–containing liposomes were detected in human umbilical vein endothelial cells and human brain microvascular endothelial cells in 3-dimensional middle cerebral artery models but not in monolayer culture consistent with flow dependency of ACE2 expression. Binding of SARS-CoV-2 S protein triggered 83 unique genes in human brain endothelial cells including upregulation of complement component C3. Conclusions: Brain endothelial cells are susceptible to direct SARS-CoV-2 infection through flow-dependent expression of ACE2. Viral S protein binding triggers a unique gene expression profile in brain endothelia that may explain the association of SARS-CoV-2 infection with cerebrovascular events.

Stroke in SARS-CoV-2 Infection: A Pictorial Overview of the Pathoetiology

“…In this model, recombinant SARS-CoV-2 spike protein attachment to ACE2 of endothelial cells induced various gene expression including the offending proteins in COVID-19 such as IL-4, IL-10, and complement C3. These findings further support the susceptibility of human brain endothelial cells to SARS-CoV-2 infection ( 63 ). Moreover, a model of human BBB showed disruption of endothelial barrier after introduction of SARS-CoV-2 spike protein via inducing a pro-inflammatory response on brain endothelium.…”

“…SARS-CoV-2 spike protein subunits seem to directly activate the alternative complement pathway on the cellular surface ( 117 ). Attachment of SARS-CoV-2 spike protein to endothelial cells upregulates the expression of C3 ( 63 ). C3 reduction, due to overactivation and conversion to active components, was related to the poor prognosis of COVID-19 patients ( 118 ).…”

COVID-19 and Cardiovascular Disease

“… 105 – 107 Whether the detected viral RNA reflected infected cardiac cells or circulating viral particles remained in question until more recently. Cardiac cellular tropism of SARS-CoV-2 has now been proven by in situ labeling of SARS-CoV-2 RNA and by electron microscopy detection of virus-like particles within cardiomyocytes, 108 interstitial cells, 105 , 107 and endothelial cells 102 , 108 , 109 of postmortem hearts. Putative SARS-CoV-2 viral particles have also been detected by electron microscopy on endomyocardial biopsy.…”

Viruses and Endogenous Retroviruses as Roots for Neuroinflammation and Neurodegenerative Diseases

“…Highly pathogenic severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a single-stranded RNA virus from the coronavirus's family (Su et al, 2016). SARS-CoV-2 enters host via its immunogenic spike glycoprotein binding to ACE2 receptor on endothelial and smooth muscle cells (Lan et al, 2020;Kaneko et al, 2021). Resultant coronavirus disease 2019 (COVID-19) mainly presents as an acute respiratory disease; however, also neurological symptoms have been reported, including dizziness, headache, encephalitis, seizures, intracerebral hemorrhage, and stroke (Benger et al, 2020;Guadarrama-Ortiz et al, 2020;Huang et al, 2020;Lu et al, 2020;Moriguchi et al, 2020).…”