Amazing stuff!
Unfortunately, the general scientific information available on the Internet about the family of coronaviruses is so tainted and crowded out with Covid-19 disease information.
The lab leak hypothesis again: From the beginning the virus was extremely infectious and as if perfectly designed to be so infectious. It is capable of infecting a broad range of cell types. Now we learn, how the virus is perhaps able to breach the blood-brain barrier. Thus, the SARS-CoV-2 virus seems to have some special features that make it apparently quite different from other, previous known human coronaviruses. If the lab leak hypothesis is confirmed one day, then the global Covid-19 pandemic was the first major quasi biological warfare incident luckily with a fairly harmless virus.
"... Tunneling nanotubes (TNTs) are delicate, hairlike structures that sprout from the cell body and pierce through neighboring cell membranes when cells are stressed, including when they’re low on oxygen or during infection. Through the tubes, which are made of the protein actin, cells can send and receive RNA, nutrients, even entire organelles—and, unfortunately, viruses. From previous work, ... [it was known] that some viruses use nanotubes to spread from cell to cell. And given the fact that SARS-CoV-2 was infecting such a broad array of cell types, she thought maybe the coronavirus could similarly exploit TNTs. ..."
From the abstract:
"Neurological manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection represent a major issue in long coronavirus disease. How SARS-CoV-2 gains access to the brain and how infection leads to neurological symptoms are not clear because the principal means of viral entry by endocytosis, the angiotensin-converting enzyme 2 receptor, are barely detectable in the brain. We report that human neuronal cells, nonpermissive to infection through the endocytic pathway, can be infected when cocultured with permissive infected epithelial cells. SARS-CoV-2 induces the formation of tunneling nanotubes (TNTs) and exploits this route to spread to uninfected cells. In cellulo correlative fluorescence and cryo–electron tomography reveal that SARS-CoV-2 is associated with TNTs between permissive cells. Furthermore, multiple vesicular structures such as double-membrane vesicles, sites of viral replication, are observed inside TNTs between permissive and nonpermissive cells. Our data highlight a previously unknown mechanism of SARS-CoV-2 spreading, likely used as a route to invade nonpermissive cells and potentiate infection in permissive cells."
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