SARS-CoV-2 infection and viral fusogens cause neuronal and glial fusion that compromises neuronal activity

The study, titled “SARS-CoV-2 infection and viral fusogens cause neuronal and glial fusion that compromises neuronal activity” conducted by Ramón Martínez-Mármol and colleagues, provides significant insights into the effects of SARS-CoV-2 on the nervous system​​.

Key Findings:

  1. Neuron and Glia Fusion: SARS-CoV-2 infection leads to the fusion of neurons with each other, and also with glial cells, in both murine hippocampal cultures and human-derived brain organoids. This phenomenon is primarily induced by viral fusogens, such as the SARS-CoV-2 spike protein and the p15 fusogen from baboon orthoreovirus​​.
  2. Fusion at Neurites and Organelle Exchange: Fusion often occurs at the neurites, far from the neuronal cell bodies, forming long fusion bridges. This allows the exchange of large molecules and organelles between fused cells, indicating a significant alteration in cellular function​​.
  3. Compromised Neuronal Activity: Fused neurons exhibited altered activity patterns. Approximately 90% of fused neurons showed synchronized activity, while the remaining 10% lost neuronal activity completely, particularly those fused at the somas. This suggests that fusion disrupts normal neuronal function and could lead to neurological complications​​.
  4. Implications for Neuroinfectious Diseases: The study underscores the potential impact of viral infections, like SARS-CoV-2, on neuronal communication and function. This could be a key mechanism underlying neurological symptoms observed in various viral infections, contributing to conditions like long COVID. The irreversible nature of this fusion might explain some of the long-term neurological consequences associated with viral infections​​.
  5. Neuropathological Consequences: The study hypothesizes that virus-induced neuronal fusion events could be linked to several neurodegenerative and neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis, among others. The ability of a single infected neuron to affect others at a distance highlights the potential widespread impact of such infections on the nervous system​​.

In summary, the study reveals that SARS-CoV-2 infection can cause neuronal and glial fusion, leading to significant changes in neuronal activity and potentially contributing to the neurological symptoms seen in COVID-19 and long COVID. This discovery adds a critical dimension to our understanding of how viruses like SARS-CoV-2 can affect brain function and cause neuropathology.

Read More: https://www.science.org/doi/epdf/10.1126/sciadv.adg2248

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