# Cellular and Molecular Mechanisms of SARS-CoV-2 Spike Protein-Induced Endothelial Dysfunction

## TL;DR

The paper explains how the SARS-CoV-2 spike protein causes damage to blood vessels, leading to inflammation and other complications in multiple organs.

## Contribution

This review synthesizes how the spike protein alone, without full viral infection, causes endothelial dysfunction through various molecular mechanisms.

## Key findings

- Spike protein disrupts endothelial homeostasis via ACE2 dysregulation and integrin engagement.
- It causes vascular inflammation, barrier disruption, and pro-inflammatory pathways.
- Therapeutic strategies to preserve endothelial integrity are discussed.

## Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is initiated by the viral spike proteins, which are key structural components that mediate host cell binding and entry and alter downstream signaling through multiple interactions with endothelial surface receptors. Endothelial dysfunction is a central consequence of COVID-19, contributing to vascular inflammation, barrier disruption, thrombosis, and multi-organ injury affecting the pulmonary, cardiovascular, cerebral, and renal systems. Emerging evidence demonstrates that spike protein-mediated effects, independent of productive viral infection, disrupt endothelial homeostasis through angiotensin-converting enzyme 2 (ACE2) dysregulation, integrin engagement, altered calcium signaling, junctional protein remodeling, oxidative stress, and pro-inflammatory and pro-apoptotic pathways. This review is intentionally focused on spike (S) protein-driven mechanisms of endothelial dysfunction; pathogenic vascular effects attributed to other SARS-CoV-2 structural proteins, including the nucleocapsid (N) protein, are beyond the scope of this discussion. In this review, we synthesize current experimental and translational data detailing the molecular mechanisms by which the SARS-CoV-2 spike protein drives endothelial dysfunction across multiple organ systems and discuss potential therapeutic strategies aimed at preserving endothelial integrity in acute COVID-19 and its long-term vascular sequela.