Skip to main content

Resistance of #endothelial cells to #SARS-CoV-2 #infection in vitro

Image
By G.M.

 


ABSTRACT

The secondary thrombotic/vascular clinical syndrome of COVID-19 suggests that SARS-CoV-2 infects the endothelium; however, robust in vitro infection of endothelial cells by various strains of SARS-CoV-2 remains to be demonstrated and continues to be debated. Here, we revisit the question of endothelial cell permissiveness to SARS-CoV-2 using isolated endothelial cells (from the lung, aorta, and endothelial cell progenitors), and additionally, to overcome limitations associated with cultured cells, using native endothelial cells within living precision cut human lung slices and single-cell RNA sequencing to track viral presence. Cellular infection in endothelial monocultures was determined using fluorescence imaging. Mediator release was measured by ELISA, and gene expression was assessed by RT-qPCR. Infection in lung slices was determined using single-cell RNA sequencing, capturing molecular identifiers that aligned to the SARS-CoV-2 viral genome (for lung slices). Each cultured endothelial cell type displayed functional viral responses by increased release of IP-10 when stimulated with Poly-IC (TLR3) or Imiquimod (TLR7/8). Compared to nasal epithelial cells, endothelial cells expressed low or undetectable levels of ACE2 and showed susceptibility to Ebola and Vesicular Stomatitis Virus glycoprotein-expressing pseudoviruses but not live SARS-CoV-2. Importantly, native endothelial cells within human lung slices displayed minimal infectability with SARS-CoV-2. To our knowledge, this is the first study to demonstrate that neither cultured nor native human endothelial cells are particularly, directly permissive to SARS-CoV-2, likely due to the lack of sufficient AEC2 expression. These observations confirm that the vascular inflammation and cardiovascular consequences of COVID-19 are largely an indirect result of paracrine inflammatory responses.


IMPORTANCE

SARS-CoV-2 is recognized not only for its acute effects and links with cardiovascular events but also for its ability to cause long COVID syndrome, which is now a major concern particularly since its long-term implications remain poorly understood. Revisiting endothelial cell permissivity to SARS-CoV-2 is therefore critical in this setting. We show that SARS-CoV-2, and several strains, do not infect cultured different types of endothelial cells cultured alone or native endothelial cells in situ in human lung tissue. Our findings are in line with the idea that vascular inflammation and thrombosis seen in COVID-19 are independent of direct endothelial cell infection and likely to be mediated by factors released by adjacent infected cells or circulating systemic inflammatory mediators. Our work also suggests that where viremia occurs, SARS-CoV-2 passes through the endothelium, facilitated by loss of barrier function because of local inflammation at the site of infection.

Source: 


Link: https://journals.asm.org/doi/full/10.1128/jvi.01205-25?af=R

____

Labels:

Comments

Post a Comment

Popular posts from this blog

#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

By G.M.
{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...
Post a Comment
Read more »

No evidence of immune #exhaustion after repeated #SARS-CoV-2 #vaccination in vulnerable and healthy populations

By G.M.
Abstract Frequent SARS-CoV-2 vaccination in vulnerable populations has raised concerns that this may contribute to T cell exhaustion , which could negatively affect the quality of immune protection. Herein, we examined the impact of repeated SARS-CoV-2 vaccination on T cell phenotypic and functional exhaustion in frail older adults in long-term care (n = 23), individuals on immunosuppressive drugs (n = 10), and healthy adults (n = 43), in Canada . Spike-specific CD4+ and CD8+ T cell levels did not decline in any cohort following repeated SARS-CoV-2 vaccination, nor did the expression of exhaustion markers on spike-specific or total T cells increase. T cell production of multiple cytokines (i.e. polyfunctionality) in response to the spike protein of SARS-CoV-2 did not decline in any cohort following repeated vaccination. None of the cohorts displayed elevated levels of terminally differentiated T cells following multiple SARS-CoV-2 vaccinations. Thus, repeated SARS-CoV-2 vaccination was...
Post a Comment
Read more »

Chimeric #hemagglutinin and #M2 #mRNA #vaccine for broad #influenza subtype protection

By G.M.
Abstract Since multiple and unpredicted influenza viruses cause seasonal epidemics and even high-risk pandemics , developing a universal influenza vaccine is essential to provide broad protection against various influenza subtypes. Combined with the mRNA lipid nanoparticle-encapsulated (mRNA-LNP) vaccine platform and chimeric immunogen strategy , we developed a novel cocktail mRNA vaccine encoding chimeric HAs (cH5/1-BV, cH7/3) and intact M2 (termed Fluaxe), which confers broad protection against major circulating IAVs and IBVs , as well as highly pathogenic avian influenza . Two-dose intramuscular immunization of Fluaxe in mice elicited cross-reactive neutralizing antibodies , T cell responses, and long-lived immunity, resulting in robust protection against multiple lethal influenza virus infections and severe acute lung injuries . In particular, intramuscular administration stimulated systemic immunity together with a prominent lung tropism of memory cells . Moreover, Fluaxe immuniza...
Post a Comment
Read more »