Covid-19 and Thousands of Other Virus Mimic Host Protein Stuctures and Functions

A recent study by Imperial College London determined that in terms of antibody and immunity, Covid-19 is very much like other coronaviruses such as SARS-CoV and MERS. A new study by Columbia University explains how coronaviruses can mimic proteins in the body, which have resulted in severe cases of Covid-19.

The findings were recently published in the journal Cell Systems describing the biological phenomenon of imitation. Mimicry is a survival mechanism of plants and animals to either trick their prey or escape predators. Similarly, viruses have proteins that imitate the three-dimensional structure of host proteins to complete its life cycle.

Professor Sagi Shapira said that basically, viruses use mimicry for deception. They hypothesized that looking for viral-like proteins could help explain how coronaviruses such as Covid-19 cause disease. The authors wrote that the mimicry of host proteins structures is a method "to harness or disrupt host cellular functions."

Virus Mimicry

Using supercomputers, the team searched for viral protein copies with a program similar to three-dimensional face recognition software. The software analyzed 7,486 viruses and over 330,000 viral proteins. Over six million instances of structural mimicry were identified where 70% of the copies would not have been recognized through protein sequencing.

Shapira explained that "Mimicry is a more pervasive strategy among viruses than we ever imagined." Imitation proteins were found in bacteria, plants, and vertebrate hosts.

Coronaviruses were among the types of viruses that used mimicry more than retroviruses and others. Covid-19's family of viruses could mimic nearly 150 proteins, including molecules that control blood coagulation or activate immune proteins that fight pathogens and cause inflammation. These systems could be driven into a hyperactive state due to the mimic proteins of the virus, explained Shapira, resulting in severe infections.

Previous research from the university found a link between coagulation proteins and severe cases of coronavirus. Patients with macular degeneration, an eye disease, had higher chances of dying from Covid-19. Those with mutated coagulation and complement (immune proteins) genes were also most likely to develop severe cases of the virus.

Developing Therapies and Interventions

Discovering pathways and the cellular targets of mimic proteins can help scientists develop better drug treatments or therapies to fight Covid-19. The current study can also help with how vaccines will be genetically engineered to target copycat viral proteins as well.

Shapira explained that the study can also determine who is at high risk of developing severe cases. At the beginning of the pandemic, senior citizens were at the highest risk of infection but soon, all ages became vulnerable to the virus.

"Viruses have already figured out how to exploit their hosts," Shapira says. Aside from discovering fundamental biological principles by studying viruses, the study can help scientists improve existing treatments and develop new ones. Moreover, aside from fighting the current pandemic, understanding viral proteins around the world can lead to the development of medical and agricultural interventions.

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