Learning how SARS-CoV2 hijacks and damages lung cells

Learning how SARS-CoV2 hijacks and damages lung cells

The emergence of the SARS-CoV2 virus has caused turmoil across the globe, forcing the researchers to study it in more detail. However, the behavior of the virus has been quite notorious. The frequent mutations and very less prior knowledge has caused some obstacles. However, scientists were acquainted that if they understand the underlying pathways in lung cells and host protein being impacted during the viral infection then there can be chances of identifying potential solutions. Considering this, scientists have recently found out how SARS-CoV2 hijacks and damages the lung cells.

The study was a multi-group collaboration between the Center for Network Systems Biology (CNSB), Center for Regenerative Medicine (CReM), and National Emerging Infectious Disease Laboratory (NEIDL). The researchers have mapped the molecular responses emerging from lung cells infected with the SAR-CoV2 virus. The finding of the study has been published in the Journal of Molecular Cell.

To understand the disease pathology and gain new insights to discover potential therapeutic targets, the researchers bioengineered the human alveolar cells. The cells when combined with high-end mass spectroscopy technology, it helped the researchers to identify potential host proteins and pathways changing during SARS-CoV2 infection. The researchers found out that lung cells infected with SAR-CoV2 have abnormal phosphorylation.

Phosphorylation is a very crucial protein modification process contributing to protein functionality in the cells. The proper phosphorylation process is important for healthy cells. However, it was noticed that the infection alters this process leading to cascading abnormal changes. These changes increase the chances of the virus to thrive within the cells and eventually destroy it.

The study also showed that as soon as the virus encounters the lung cells, it initiates exploiting the resources required for the normal functioning and growth of the cell. The invasion of the virus further disrupts the functioning of the cell and damaging it extensively. The resources used, powers the virus eventually leading to rapid proliferation and expansion in nearby regions. As a result, the exhausted and damaged cells undergo self-destruction and the virus starts infecting the cells in the vicinity while evading the body’s immune system. This cycle repeats continuously leading to the hijacking of lung cells and widespread damage.

The researchers examined lung alveolar cells from one to 24 hours after infection with SARS-CoV-2 to understand what changes occur in lung cells immediately (at one, three, and six hours after infection by SARS-CoV-2) and what changes occur later (at 24 hours after infection). These changes were then compared to uninfected cells. All proteins from infected and uninfected alveolar cells, corresponding to the different time-points were extracted and labeled with unique barcoding tags called “tandem mass tag.” These tags, which can be accurately detected only by a mass spectrometer, permit robust quantification of protein and phosphorylation abundance in cells.

“Our results showed that in comparison to normal/uninfected lung cells, SARS-CoV-2 infected lung cells showed dramatic changes in the abundance of thousands of proteins and phosphorylation events,” said Darrell Kotton, MD, BUSM, CReM.

“Moreover, our data also showed that the SARS-CoV-2 virus induces a significant number of these changes as early as one-hour post-infection and lays the foundation for a complete hijack of the host lung cells,” adds Elke Mehlberger, PhD, NEIDL.

Scientists also tried to examine the data obtained from the study to identify any potential opportunities for COVID-19 treatment. They found that about more than 18 existing drugs that have been already clinically approved can be re-purposed for the treatment. The research team believes that the current findings are very crucial and can contribute a lot to the field, specifically in terms of devising a cost-effective, robust and life-saving treatment to overcome COVID-19.

 

COVID-19: Loss of smell, a new symptom added to the list

COVID-19: Loss of smell, a new symptom added to the list

New evidence finds that anosmia- loss of smell as a new symptom caused by the COVID-19 virus. Experts believe that it can be added as a potential screening tool for the novel viral infection, and here’s why!

Cases of post-viral anosmia are one of the leading causes of loss of smell among adults suffering from viral infection. This has been associated with previous coronaviruses which are usually known to cause upper respiratory tract infections and have accounted for 10-15% of the cases. Therefore it comes off as no surprise that the current novel COV ID-19 virus also causes anosmia in the infected. 

A significant number of cases from South Korea, Italy, and China prove as good evidence for COVID-19 patients developing anosmia. More than 2 out of 3 confirmed cases in Europe have been diagnosed with anosmia. It is also noticed that several COVID-19 cases also present anosmia as the only symptom. Given the above evidence, experts contemplate using anosmia of a screening tool to diagnose people with COVID-19 at the early stages. 

Cases of anosmia reflect how COVID-19 affects the brain:

“There’s something unusual about the relationship between COVID-19 and smell,” states Sandeep Robert Datta a neuroscientist from Harvard Medical School and one of the leading scientists in the study. It is well known that common cold, is associated with stuffy noses leading to a temporary loss of smell, but it found that the COVID-19 virus leaves the nose free. “But recently lots of people are complaining about losing their sense of smell when they don’t feel stuffed up at all,” Datta says. 

The team further experimented on nose cells, including the support cells and nerve cells sending messages to the brain using both mice and human models. This was especially performed to see if there were any signs of a link between the cells and the ACE2 receptor. A small recap: ACE2 receptor is the primary receptor in humans which the COVID-19 viruses used to attach to the host and cause infection. 

The researchers from the study found that the results demonstrated a molecular signal showing that ACE2 receptors were present in nose cells and the subsidiary cells. These cells generally maintain a chemical balance in the nose, which allows the nerve cells to send smell signals to the brain. 

A Contradicting study published by a team from Nicolaus Copernicus University, Poland resulted that the olfactory neurons did not pose any ACE2 receptors, implying that the novel virus cant infect the cells themselves. 

It was also noticed that the timing of the onset of anosmia symptoms was varied, with some patients developing the symptoms at early stages, while another group of patients reported the loss of smell in the later stages of their illness. 

How will this help in the fight against COIVD-19?

More studies need to be conducted regarding the frequency of the symptoms and the exact science behind how the COVID-19 virus affects the olfactory senses. To collect more data on the cases posing these symptoms, the AOS-HNS Infectious Disease and Patient Safety Quality Improvement Committees have developed a COVID-19 anosmia detecting tool for health care workers. Using this tool the clinicians of all specialties will be able to confidently confirm cases portraying the loss of smell. 

The idea of adding the symptoms of unexplained anosmia as an official symptom of COVID-19 can help with earlier detection and isolation of potential carriers of the virus and improve safety by containing the spread of the virus. 

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