Scientists Are Working to Develop a Clever Nasal Spray That Tricks the Coronavirus Out of the Body
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.
Imagine this scenario: you get an annoying cough and a bit of a fever. When you wake up the next morning you lose your sense of taste and smell. That sounds familiar, so you head to a doctor's office for a Covid test, which comes back positive.
Your next step? An anti-Covid nasal spray of course, a "trickster drug" that will clear the once-dangerous and deadly virus out of the body. The drug works by tricking the coronavirus with decoy receptors that appear to be just like those on the surface of our own cells. The virus latches onto the drug's molecules "thinking" it is breaking into human cells, but instead it flushes out of your system before it can cause any serious damage.
This may sounds like science fiction, but several research groups are already working on such trickster coronavirus drugs, with some candidates close to clinical trials and possibly even becoming available late this year. The teams began working on them when the pandemic arrived, and continued in lockdown.
This may sounds like science fiction, but several research groups are already working on such trickster coronavirus drugs, with some candidates close to clinical trials and possibly even becoming available late this year. The teams began working on them when the pandemic arrived, and continued in lockdown.
When the pandemic first hit and the state of California issued a lockdown order on March 16, postdoctoral researchers Anum and Jeff Glasgow found themselves stuck at home with nothing to do. The two scientists who study bioengineering felt that they were well equipped to research molecular ways of disabling coronavirus's cell-penetrating spike protein, but they could no longer come to their labs at the University of California San Francisco.
"We were upset that no one put us in the game," says Anum Glasgow. "We have a lot of experience between us doing these types of projects so we wanted to contribute." But they still had computers so they began modeling the potential virus-disabling proteins in silico using Robetta, special software for designing and modeling protein structures, developed and maintained by University of Washington biochemist David Baker and his lab.
"We saw some imperfections in that lock and key and we created something better. We made a 10 times tighter adhesive."
The SARS-CoV-2 virus that causes Covid-19 uses its surface spike protein to bind on to a specific receptor on human cells called ACE2. Unfortunately for humans, the spike protein's molecular shape fits the ACE2 receptor like a well-cut key, making it very successful at breaking into our cells. But if one could design a molecular ACE2-mimic to "trick" the virus into latching onto it instead, the virus would no longer be able to enter cells. Scientists call such mimics receptor traps or inhibitors, or blockers. "It would block the adhesive part of the virus that binds to human cells," explains Jim Wells, professor of pharmaceutical chemistry at UCSF, whose lab took part in designing the ACE2-receptor mimic, working with the Glasgows and other colleagues.
The idea of disabling infectious or inflammatory agents by tricking them into binding to the targets' molecular look-alikes is something scientists have tried with other diseases. The anti-inflammatory drugs commonly used to treat autoimmune conditions, including rheumatoid arthritis, Crohn's disease and ulcerative colitis, rely on conceptually similar molecular mechanisms. Called TNF blockers, these drugs block the activity of the inflammatory cytokines, molecules that promote inflammation. "One of the biggest selling drugs in the world is a receptor trap," says Jeff Glasgow. "It acts as a receptor decoy. There's a TNF receptor that traps the cytokine."
In the recent past, scientists also pondered a similar look-alike approach to treating urinary tract infections, which are often caused by a pathogenic strain of Escherichia coli. An E. coli bacterium resembles a squid with protruding filaments equipped with proteins that can change their shape to form hooks, used to hang onto specific sugar molecules called ligands, which are present on the surface of the epithelial cells lining the urinary tract.
A recent study found that a sugar-like compound that's structurally similar to that ligand can play a similar trick on the E. Coli. When administered in in sufficient amounts, the compound hooks the bacteria on, which is then excreted out of the body with urine. The "trickster" method had been also tried against the HIV virus, but it wasn't very effective because HIV has a high mutation rate and multiple ways of entering human cells.
But the coronavirus spike protein's shape is more stable. And while it has a strong affinity for the ACE2 receptors, its natural binding to these receptors isn't perfect, which allowed the UCSF researchers to design a mimic with a better grip. "We saw some imperfections in that lock and key and we created something better," says Wells. "We made a 10 times tighter adhesive." The team demonstrated that their traps neutralized SARS-CoV-2 in lab experiments and published their study in the Proceedings of the National Academy of Sciences.
Baker, who is the director of the Institute for Protein Design at the University of Washington, was also devising ACE2 look-alikes with his team. Only unlike the UCSF team, they didn't perfect the virus-receptor lock and key combo, but instead designed their mimics from scratch. Using Robetta, they digitally modeled over two million proteins, zeroed-in on over 100,000 potential candidates and identified a handful with a strong promise of blocking SARS-CoV-2, testing them against the virus in human cells. Their design of the miniprotein inhibitors was published in the journal Science.
Biochemist David Baker, pictured in his lab at the University of Washington.
UW
The concept of the ACE2 receptor mimics is somewhat similar to the antibody plasma, but better, the teams explain. Antibodies don't always coat all of the virus's spike proteins and sometimes don't bind perfectly. By contrast, the ACE2 mimics directly compete with the virus's entry mechanism. ACE2 mimics are also easier and cheaper to make, researchers say.
Antibodies, which are long protein chains, must be grown inside mammalian cells, which is a slow and costly process. As drugs, antibody cocktails must be kept refrigerated. On the contrary, proteins that mimic ACE2 receptors are smaller and can be produced by bacteria easily and inexpensively. Designed to specs, these proteins don't need refrigeration and are easy to store. "We designed them to be very stable," says Baker. "Our computation design tries to come up with the stable proteins that have the desired functions."
That stability may allow the team to create an inhaler drug rather than an intravenous one, which would be another advantage over the antibody plasma, given via an IV. The team envisions people spraying the miniprotein solution into their nose, creating a protecting coating that would disable the inhaled virus. "The infection starts from your respiratory system, from your nose," explains Longxing Cao, the study's co-author—so a nasal spray would be a natural way to administer it. "So that you can have it like a layer, similar to a mask."
As the virus evolves, new variants are arising. But the teams think that their ACE2 protein mimics should work on the new variants too for several reasons. "Since the new SARS-CoV-2 variants still use ACE2 for their cell entry, they will likely still be susceptible to ACE2-based traps," Glasgow says.
Cao explains that their approach should work too because most of the mutations happen outside the ACE2 binding region. Plus, they are building multiple binders that can bind to an array of the coronavirus variants. "Our binder can still bind with most of the variants and we are trying to make one protein that could inhibit all the future escape variants," he says.
Baker and Cao hope that their miniproteins may be available to patients later this year. But besides getting the medicine out to patients, this approach will allow researchers to test the computer-modeled mimics end-to-end with an unprecedented speed. That would give humans a leg up in future pandemics or zoonotic disease outbreaks, which remain an increasingly pressing threat due to human activity and climate change.
"That's what we are focused on right now—understanding what we have learned from this pandemic to improve our design methods," says Baker. "So that we should be able to obtain binders like these very quickly when a new pandemic threat is identified."
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.
When a patient is diagnosed with early-stage breast cancer, having surgery to remove the tumor is considered the standard of care. But what happens when a patient can’t have surgery?
Whether it’s due to high blood pressure, advanced age, heart issues, or other reasons, some breast cancer patients don’t qualify for a lumpectomy—one of the most common treatment options for early-stage breast cancer. A lumpectomy surgically removes the tumor while keeping the patient’s breast intact, while a mastectomy removes the entire breast and nearby lymph nodes.
Fortunately, a new technique called cryoablation is now available for breast cancer patients who either aren’t candidates for surgery or don’t feel comfortable undergoing a surgical procedure. With cryoablation, doctors use an ultrasound or CT scan to locate any tumors inside the patient’s breast. They then insert small, needle-like probes into the patient's breast which create an “ice ball” that surrounds the tumor and kills the cancer cells.
Cryoablation has been used for decades to treat cancers of the kidneys and liver—but only in the past few years have doctors been able to use the procedure to treat breast cancer patients. And while clinical trials have shown that cryoablation works for tumors smaller than 1.5 centimeters, a recent clinical trial at Memorial Sloan Kettering Cancer Center in New York has shown that it can work for larger tumors, too.
In this study, doctors performed cryoablation on patients whose tumors were, on average, 2.5 centimeters. The cryoablation procedure lasted for about 30 minutes, and patients were able to go home on the same day following treatment. Doctors then followed up with the patients after 16 months. In the follow-up, doctors found the recurrence rate for tumors after using cryoablation was only 10 percent.
For patients who don’t qualify for surgery, radiation and hormonal therapy is typically used to treat tumors. However, said Yolanda Brice, M.D., an interventional radiologist at Memorial Sloan Kettering Cancer Center, “when treated with only radiation and hormonal therapy, the tumors will eventually return.” Cryotherapy, Brice said, could be a more effective way to treat cancer for patients who can’t have surgery.
“The fact that we only saw a 10 percent recurrence rate in our study is incredibly promising,” she said.
Few things are more painful than a urinary tract infection (UTI). Common in men and women, these infections account for more than 8 million trips to the doctor each year and can cause an array of uncomfortable symptoms, from a burning feeling during urination to fever, vomiting, and chills. For an unlucky few, UTIs can be chronic—meaning that, despite treatment, they just keep coming back.
But new research, presented at the European Association of Urology (EAU) Congress in Paris this week, brings some hope to people who suffer from UTIs.
Clinicians from the Royal Berkshire Hospital presented the results of a long-term, nine-year clinical trial where 89 men and women who suffered from recurrent UTIs were given an oral vaccine called MV140, designed to prevent the infections. Every day for three months, the participants were given two sprays of the vaccine (flavored to taste like pineapple) and then followed over the course of nine years. Clinicians analyzed medical records and asked the study participants about symptoms to check whether any experienced UTIs or had any adverse reactions from taking the vaccine.
The results showed that across nine years, 48 of the participants (about 54%) remained completely infection-free. On average, the study participants remained infection free for 54.7 months—four and a half years.
“While we need to be pragmatic, this vaccine is a potential breakthrough in preventing UTIs and could offer a safe and effective alternative to conventional treatments,” said Gernot Bonita, Professor of Urology at the Alta Bro Medical Centre for Urology in Switzerland, who is also the EAU Chairman of Guidelines on Urological Infections.
The news comes as a relief not only for people who suffer chronic UTIs, but also to doctors who have seen an uptick in antibiotic-resistant UTIs in the past several years. Because UTIs usually require antibiotics, patients run the risk of developing a resistance to the antibiotics, making infections more difficult to treat. A preventative vaccine could mean less infections, less antibiotics, and less drug resistance overall.
“Many of our participants told us that having the vaccine restored their quality of life,” said Dr. Bob Yang, Consultant Urologist at the Royal Berkshire NHS Foundation Trust, who helped lead the research. “While we’re yet to look at the effect of this vaccine in different patient groups, this follow-up data suggests it could be a game-changer for UTI prevention if it’s offered widely, reducing the need for antibiotic treatments.”