Circulating Exosomes Are Strongly Involved in SARS-CoV-2 Infection

Area of Science:

• Virology
• Immunology
• Proteomics
• Biomarker Discovery

Background:

• Limited understanding of host response to SARS-CoV-2 hinders COVID-19 pathogenesis insights and therapeutic development.
• Exosomes and extracellular vesicles released during viral infections can modulate the immune response.
• Investigating host exosome response to SARS-CoV-2 is crucial for understanding disease mechanisms.

Purpose of the Study:

• To map the host circulating exosome response to SARS-CoV-2 infection using shotgun proteomics.
• To investigate how SARS-CoV-2 modulates exosome content and their role in disease progression.
• To evaluate the potential of plasma exosomes as biomarkers for COVID-19 severity.

Main Methods:

• Shotgun proteomic analysis of patient-derived exosomes.
• Identification of exosomal proteins involved in immune response, inflammation, coagulation, and complement pathways.
• Detection of SARS-CoV-2 RNA within the exosomal cargo.

Main Results:

• Proteomic analysis revealed molecules linked to inflammation, coagulation, and complement activation, key in COVID-19 tissue damage.
• Identified potential diagnostic biomarkers (e.g., fibrinogen, fibronectin) with high area under the curve (AUC) values.
• Detected proteins correlating with disease severity and, for the first time, SARS-CoV-2 RNA in exosomes, suggesting a role in viral spread.

Conclusions:

• Circulating exosomes significantly contribute to inflammation, coagulation, and immunomodulation during SARS-CoV-2 infection.
• Plasma exosomes show promise as biomarkers for COVID-19 diagnosis and severity assessment.
• The presence of viral RNA in exosomes suggests a potential mechanism for SARS-CoV-2 infection spread via endocytosis.