Scientists at the University of California have made a significant discovery regarding the SARS-CoV-2 virus and its ability to induce sneezing. The research has uncovered a specific viral protein, PLpro, which stimulates neurons in the respiratory passages and triggers the sneeze reflex. This finding not only provides insight into a previously unknown symptom of COVID-19 but also opens up new possibilities for treatment and reducing transmission.
Traditionally, sneezing has been considered an incidental byproduct of illness, resulting from infected cells releasing molecules that irritate nasal passages. However, the recent study conducted by Dr. Diana Bautista and her team suggests a more direct role for the SARS-CoV-2 virus in the sneezing reflex. The researchers found that the viral protein PLpro, produced in significant amounts by infected cells, directly activates sensory neurons responsible for inducing sneezing.
The study involved introducing PLpro into the noses of mice, which led to a rapid and robust sneezing response. This not only confirmed the connection between the viral protein and the sneeze reflex but also raised concerns about its potential role in promoting virus transmission. The researchers discovered that PLpro stimulates calcium influx in sensory neurons, triggering the release of large quantities of nasal secretions, which could contribute to the spread of the virus.
Furthermore, the study delved into the impact of PLpro on other COVID-19 symptoms. Mice injected with PLpro displayed face and mouth pain, which are commonly reported by COVID-19 patients. The researchers also found that PLpro triggered nocifensive behaviors, such as nose rubbing, suggesting its role in inducing irritation and pain.
In addition to its implications for COVID-19, the researchers tested PLpro from other coronaviruses, including the severe acute respiratory syndrome (SARS) virus, and found that it also stimulates sensory neurons. This suggests that the phenomenon of PLpro-triggered sneezing may extend beyond SARS-CoV-2 to other coronaviruses and even viruses causing common colds.
While the findings are promising, caution is advised. Dr. Felipe Ribeiro, a neuroimmunologist from Washington University School of Medicine, urges researchers to rule out the possibility that sneezing might have a beneficial role in the recovery from COVID-19. It is important to demonstrate that blocking the sneezing reflex is safe and does not hinder the overall healing process.
The study also highlights the presence of PLpro in other coronaviruses, such as SARS and Middle East respiratory syndrome (MERS), although variations in structure and efficiency were noted. This raises questions about whether PLpro from other viruses, including those causing the common cold, may also trigger sneezing and pain.
The research goes into detail about the molecular mechanisms through which PLpro activates sensory neurons. The protein, released from infected cells, stimulates specific neurons that express ion channels, resulting in behaviors like sneezing, nose rubbing, and orofacial pain.
In terms of long-term effects, the study suggests a potential link between PLpro and Long COVID. Over 10% of SARS-CoV-2 patients experience chronic symptoms, including headache and peripheral neuropathy. The research indicates that PLpro may persist in the body even after active infection, contributing to long-lasting changes in sensory neurons and potentially influencing chronic symptoms.
The significance of PLpro in SARS-CoV-2 infection and symptom manifestation makes it a potential therapeutic target. Researchers are already exploring PLpro as a drug target, with several compounds inhibiting the protein in preclinical development. This presents the possibility that targeting PLpro could not only hinder viral replication but also alleviate symptoms and reduce transmission.
In conclusion, the study provides a deeper understanding of how SARS-CoV-2 induces sneezing and sheds light on the intricate mechanisms of the virus. The role of PLpro in stimulating sensory neurons not only enhances our knowledge of COVID-19 symptoms but also offers potential avenues for treatment. Targeting PLpro could be a promising strategy to alleviate symptoms, hinder transmission, and address the enigma of Long COVID. Ongoing research into the interplay between PLpro and the human body offers hope for more effective treatments and a comprehensive understanding of the long-term effects of this global health crisis.