Clinical laboratories continue to report positive COVID-19 tests for individuals that have been vaccinated and even previously infected with the same variant of the coronavirus
Researchers across the globe continue to study the SARS-CoV-2 coronavirus and its many variants. Their goals are to curb the spread of the disease and develop new therapies and treatments for optimal patient outcomes. Now, a study conducted by scientists at the University of Missouri (UM) provides deeper insight into the processes the virus uses to mutate and overpower the human immune system. These findings could lead to improved antivirals and clinical laboratory tests for COVID-19.
The UM team identified specific mutations occurring within the virus’ spike protein that help Omicron subvariants evade existing antibodies and create an infection. These mutations may explain why some people who have had previous COVID-19 infections and/or who are fully vaccinated continue to test positive for SARS-CoV-2, and why the virus continues to evolve.
“Omicron now has more than 130 sublineages and they have been here for quite a while. We are now just finally able to detect them and differentiate among them with this research,” said Kamlendra Singh, PhD, associate research professor in the Department of Veterinary Pathobiology at UM’s College of Veterinary Medicine, in a UM press release.
“Previous variants, including Alpha, Beta, Gamma, and Delta, contributed to many of the mutations occurring now with these Omicron variants. So, our research shows how the virus has evolved over time with new mutations,” he added.
“Throughout the pandemic, the [SARS-CoV-2] virus has continued to get smarter and smarter. Even with vaccines, it continues to find new ways to mutate and evade existing antibodies,” said Kamlendra Singh, PhD (above), Associate Research Professor, College of Veterinary Medicine at University of Missouri, in a UM press release. This research team’s findings may help clinical laboratories further develop their SARS-CoV-2 antibody tests. (Photo copyright: University of Missouri.)
Antibodies for One Variant, but Not for Another
The scientists began their investigation by researching online databases that track COVID-19 cases and analyzing the protein sequences from more than 10 million Omicron-related samples that were collected from around the world since November of last year.
They examined the available sequences, structures of spike/receptor and spike/antibody complexes of the samples, and then conducted molecular dynamics simulations. The team utilized 3D modeling to locate where mutations occur and created structures of the spike protein to determine how the mutations are affected by antibodies and vaccinations.
The researchers found that the Omicron variant continues to mutate and has become extremely efficient at adaptation. Reinfections are happening because many individuals do not possess the antibodies for the new subvariants that continue to develop.
“Vaccinated individuals, or those who have previously tested positive, may have the antibodies for one variant but not necessarily for any of the other variants,” Singh explained. “The various mutations may seem like only subtle differences, but they are very important.”
The UM scientists’ research shows it is possible to differentiate Omicron subvariants from each other and pinpoint how certain mutations might become problematic for patients. According to Singh, many people can be infected with multiple variants at the same time. He is hopeful that their work will make it possible for vaccines and other treatments to specifically target different strains of the virus.
Singh also believes that the coronavirus is most likely never going to disappear from society and that new variants and their sublineages will continue to appear and evolve.
“The ultimate solution going forward will likely be the development of small molecule, antiviral drugs that target parts of the virus that do not mutate,” Singh said. “While there is no vaccine for HIV, there are very effective antiviral drugs that help those infected live a healthy life, so hopefully the same can be true with COVID-19.”
Omicron Subvariants May Be Here to Stay
“I am proud of my team’s efforts, as we have identified specific mutations for various variants throughout the pandemic, and it feels good to be contributing to research that is assisting with the situation,” Singh said. “We will continue to help out, as there will surely be new variants in the future.”
Singh is also part of a team that developed a supplement called CoroQuil-Zn, which was designed to reduce a patient’s viral load after being infected with SARS-CoV-2. The drug is currently being used in parts of India and is awaiting approval from the US Food and Drug Administration (FDA).
Clinical laboratories that perform antibody testing for SARS-CoV-2 infections should be aware that the coronavirus will likely be moving among humans for many years to come. This recent research may aid in the development of new antivirals, treatments, and vaccines that target specific subvariants for the best patient outcomes.
The scientist also employed machine learning “to gauge how easily accessible genes are for transcription” in research that could lead to new clinical laboratory diagnostic tests
Anatomic pathologists and clinical laboratories are of course familiar with the biological science of genomics, which, among other things, has been used to map the human genome. But did you know that a three-dimensional (3D) map of a genome has been created and that it is helping scientists understand how DNA regulates its organization—and why?
The achievement took place at St. Jude Children’s Research Hospital (St. Jude) in Memphis, Tenn. Scientists there created “the first 3D map of a mouse genome” to study “the way cells organize their genomes during development,” a St. Jude news release noted.
Some experts predict that this new approach to understanding how changes happen in a genome could eventually provide new insights that anatomic pathologists and clinical laboratory scientists could find useful when working with physicians to diagnose patients and using the test results to identify the most appropriate therapy for those patients.
In addition to 3D modeling, the researchers applied machine learning to data from multiple sources to see how the organization of the genome changed at different times during development. “The changes are not random, but part of the developmental program of cells,” Dyer said in the news release.
The St. Jude study focused on the rod cells in a mouse retina. That may seem like a narrow scope, but there are more than 8,000 genes involved in retinal development in mice, during which those genes are either turned on or off.
To see what was happening among the cells, the researchers used HI-C analysis, an aspect of ultra-deep chromosome conformation capture, in situ. They found that the loops in the DNA bring together regions of the genome, allowing them to interact in specific ways.
Until this study, how those interactions took place was a
mystery.
“Understanding the way cells organize their genomes during development will help us to understand their ability to respond to stress, injury and disease,”Michael Dyer, PhD (above), Chair of St. Jude’s Developmental Neurobiology Department, co-leader of the Developmental Biology and Solid Tumor Program, and Investigator at Howard Hughes Medical Institute (HHMI), said in the news release. (Photo copyright: St. Jude Children’s Research Hospital.)
The scientists also discovered there were DNA promoters, which encourage gene expression, and also DNA enhancers that increase the likelihood gene expression will occur.
“The research also included the first report of a powerful regulator of gene expression, a super enhancer, that worked in a specific cell at a specific stage of development,” the news release states. “The finding is important because the super enhancers can be hijacked in developmental cancers of the brain and other organs.”
St. Jude goes on to state, “In this study, the scientists determined that when a core regulatory circuit super-enhancer for the VSX2 gene was deleted, an entire class of neurons (bipolar neurons) was eliminated. No other defects were identified. Deletion of the VSX2 gene causes many more defects in retinal development, so the super-enhancer is highly specific to bipolar neurons.”
The St. Jude researchers developed a genetic mouse model of
the defect that scientists are using to study neural circuits in the retina,
the news release states.
Research Technologist Victoria Honnell (left); Developmental Neurobiologist Jackie Norrie, PhD (center); and Postdoctoral Researcher Marybeth Lupo, PhD (right), work in the St. Jude clinical laboratory of Michael Dyer, PhD, using 3D genomic mapping to study gene regulation during development and disease. (Photo copyright: St. Jude Children’s Research Hospital.)
DNA Loops May Matter to Pathology Sooner Rather than
Later
Previous researcher studies primarily used genomic sequencing technology to locate and investigate alterations in genes that lead to disease. In the St. Jude study, the researchers examined how DNA is packaged. If the DNA of a single cell could be stretched out, it would be more than six feet long. To fit into the nucleus of a cell, DNA is looped and bundled into a microscopic package. The St. Jude scientists determined that how these loops are organized regulates how the cell functions and develops.
Scientists around the world will continue studying how the loops in DNA impact gene regulation and how that affects the gene’s response to disease. At St. Jude Children’s Research Hospital, Dyer and his colleagues “used the same approach to create a 3D genomic map of the mouse cerebellum, a brain structure where medulloblastoma can develop. Medulloblastoma is the most common malignant pediatric brain tumor,” noted the St. Jude’s news release.
In addition to providing an understanding of how genes
function, these 3D studies are providing valuable insight into how some
diseases develop and mature. While nascent research such as this may not impact
pathologists and clinical laboratories at the moment, it’s not a stretch to
think that this work may lead to greater understanding of the pathology of
diseases in the near future.
