Nikhil Prasad Fact checked by:Thailand Medical News Team Apr 29, 2025 1 day, 4 hours, 3 minutes ago
Medical News: In an important new discovery, researchers have found that COVID-19 not only causes respiratory symptoms and other complications, but also leads to significant changes at the genetic level. Scientists from the University of Cagliari, the Technical University of Dresden, the University of Sassari, and the Hospital SS. Trinità in Italy have uncovered how infection with SARS-CoV-2 results in exponential DNA methylation in a key gene called TAS2R38 — a receptor gene involved in both taste sensation and immune response.
COVID-19 Causes Exponential DNA Methylation in the TAS2R38 Gene
This
Medical News report sheds light on the detailed findings of this major study, revealing how changes in the TAS2R38 gene might be linked to the severity of COVID-19 symptoms, and how these genetic modifications may reverse after recovery.
Understanding the TAS2R38 Gene and Its Role in Immunity
The TAS2R38 gene encodes a bitter taste receptor that is not only active in the mouth but also found in other parts of the body such as the lungs, brain, kidneys, and gastrointestinal tract. In the respiratory system, TAS2R38 plays a defensive role, helping the body fend off harmful pathogens by triggering the release of nitric oxide (NO), a natural compound known to inhibit the replication of viruses like SARS-CoV-2.
However, variations in the TAS2R38 gene — referred to as single nucleotide polymorphisms (SNPs) — can affect how well this receptor functions. People with a certain version of the gene (called PAV/PAV) have a stronger receptor function, while those with other versions (like AVI/AVI) show weaker receptor activity, making them more susceptible to infections.
How COVID-19 Changes the TAS2R38 Gene
The study involved 84 participants from Sardinia, Italy, including those infected with COVID-19 and others who had recovered. Researchers collected nasopharyngeal swabs and saliva samples, analyzed the TAS2R38 gene, and specifically examined DNA methylation at a site called cg25481253 — a specific location within the gene.
DNA methylation is a process where chemical tags are added to the DNA molecule, often leading to the suppression of gene activity. It is a normal part of how genes are regulated, but abnormal methylation patterns are associated with various diseases.
The researchers found that during active COVID-19 infection, patients — especially those with severe symptoms — showed dramatically increased methylation at the cg25481253 site of the TAS2R38 gene. Essentially, COVID-19 was silencing this crucial gene, potentially weakening the body's innate immune response.
Those with severe COVID-19 had the highest levels of methylation, suggesting a direct link between disease severity and genetic suppression. Interestingly, once patients recovered, the methylation levels began returning to normal, indicating that these changes were reversible.
Genetic Variants Affect Recover
y Too
Another remarkable finding was the relationship between an individual’s TAS2R38 genotype and their methylation patterns after recovery. People with the PAV/PAV genotype, known for stronger receptor activity, had significantly lower levels of DNA methylation after infection compared to those with other genotypes. This suggests they could restore their TAS2R38 gene activity more easily after the virus was cleared.
In contrast, individuals carrying the weaker AVI/AVI genotype showed higher residual methylation, possibly making their immune systems slower to recover to full strength.
This genotype-based difference hints at why some people might bounce back faster after COVID-19, while others may continue to experience lingering symptoms for months.
Detailed Study Insights
The study divided participants into groups based on the severity of their COVID-19 symptoms: severe, mild-to-moderate, and asymptomatic. DNA methylation was measured during active infection and again after recovery. The statistical analysis revealed that during infection, severe cases had significantly lower ΔCt values — a marker of higher methylation — compared to mild cases or asymptomatic individuals.
Importantly, after recovery, differences in methylation between the groups faded, supporting the idea that the methylation induced by SARS-CoV-2 is a temporary reaction rather than a permanent genetic alteration.
Moreover, the TAS2R38 methylation profile was notably linked to participants' specific genetic makeup only after recovery, not during the infection. This observation strengthens the idea that the virus temporarily overrides the body's natural genetic tendencies during infection.
Why These Findings Matter
This discovery provides new insights into how SARS-CoV-2 manipulates the human body at a molecular level to enhance its own survival. By silencing a gene that plays a role in fighting infections, the virus may create conditions that allow it to spread more easily and cause more severe illness.
The reversibility of the methylation changes is good news because it suggests that once the virus is cleared, the body can eventually restore normal gene function. However, the timeline for full recovery may vary depending on the individual’s genetic background.
These results also open up new possibilities for identifying people at higher risk of severe COVID-19 based on their TAS2R38 genotype and for developing treatments that could prevent the virus from shutting down this important immune defense.
Study Limitations and Future Directions
The researchers caution that while their study offers strong evidence of a link between TAS2R38 methylation and COVID-19 severity, the sample size was relatively small. Larger studies are needed to confirm these findings in different populations and ethnic groups.
Future research could also explore whether methylation changes in other immune-related genes contribute to COVID-19 outcomes, and whether interventions could reverse harmful epigenetic modifications faster.
Understanding these molecular changes is essential not only for fighting COVID-19 but also for preparing for future viral pandemics that might use similar strategies to bypass the immune system.
Conclusion
The study carried out by researchers from the University of Cagliari, the Technical University of Dresden, the University of Sassari, and the Hospital SS. Trinità presents groundbreaking evidence that COVID-19 can cause exponential DNA methylation in the TAS2R38 gene. This silencing of a key immune receptor during infection appears to be closely linked to the severity of symptoms. Thankfully, the methylation changes are reversible after recovery, offering hope for full restoration of immune defenses over time. Additionally, individuals with the PAV/PAV genotype seem to have a genetic advantage both during and after infection, as their TAS2R38 genes are less susceptible to lasting methylation. These findings open exciting new paths for using genetic and epigenetic markers to predict COVID-19 severity and recovery trajectories. Further studies with larger groups are needed to validate these observations and to possibly translate them into clinical practice, such as personalized treatment plans or preventive measures based on genetic risk profiles.
The study findings were published in the peer-reviewed journal: Scientific Reports.
https://www.nature.com/articles/s41598-025-95879-x
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https://www.thailandmedical.news/news/even-mild-or-asymptomatic-covid-19-infections-leave-over-700-dna-methylation-changes-after-recovery
https://www.thailandmedical.news/news/belgium-scientists-provide-new-insights-into-dna-methylation-telomere-length-and-immune-function-in-long-covid-patients
https://www.thailandmedical.news/news/covid-19-induces-epigenetic-changes-in-nasal-cells,-resulting-in-long-term-breathing-issues
https://www.thailandmedical.news/articles/coronavirus
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