How mRNA Could Revolutionize Medicine
In November 2020, messenger RNA catapulted into the public consciousness when the first COVID-19 vaccines were authorized for emergency use. Around the same time, an equally groundbreaking yet relatively unheralded application of mRNA technology was taking place at a London hospital.
Over the past two decades, there's been increasing interest in harnessing mRNA — molecules present in all of our cells that act like digital tape recorders, copying instructions from DNA in the cell nucleus and carrying them to the protein-making structures — to create a whole new class of therapeutics.
Scientists realized that artificial mRNA, designed in the lab, could be used to instruct our cells to produce certain antibodies, turning our bodies into vaccine-making factories, or to recognize and attack tumors. More recently, researchers recognized that mRNA could also be used to make another groundbreaking technology far more accessible to more patients: gene editing. The gene-editing tool CRISPR has generated plenty of hype for its potential to cure inherited diseases. But delivering CRISPR to the body is complicated and costly.
"Most gene editing involves taking cells out of the patient, treating them and then giving them back, which is an extremely expensive process," explains Drew Weissman, professor of medicine at the University of Pennsylvania, who was involved in developing the mRNA technology behind the COVID-19 vaccines.
But last November, a Massachusetts-based biotech company called Intellia Therapeutics showed it was possible to use mRNA to make the CRISPR system inside the body, eliminating the need to extract cells out of the body and edit them in a lab. Just as mRNA can instruct our cells to produce antibodies against a viral infection, it can also teach them to produce one of the two components that make up CRISPR — a cutting protein that snips out a problem gene.
"The pandemic has really shown that not only are mRNA approaches viable, they could in certain circumstances be vastly superior to more traditional technologies."
In Intellia's London-based clinical trial, the company applied this for the first time in a patient with a rare inherited liver disease known as hereditary transthyretin amyloidosis with polyneuropathy. The disease causes a toxic protein to build up in a person's organs and is typically fatal. In a company press release, Intellia's president and CEO John Leonard swiftly declared that its mRNA-based CRISPR therapy could usher in a "new era of potential genome editing cures."
Weissman predicts that turning CRISPR into an affordable therapy will become the next major frontier for mRNA over the coming decade. His lab is currently working on an mRNA-based CRISPR treatment for sickle cell disease. More than 300,000 babies are born with sickle cell every year, mainly in lower income nations.
"There is a FDA-approved cure, but it involves taking the bone marrow out of the person, and then giving it back which is prohibitively expensive," he says. It also requires a patient to have a matched bone marrow done. "We give an intravenous injection of mRNA lipid nanoparticles that target CRISPR to the bone marrow stem cells in the patient, which is easy, and much less expensive."
Cancer Immunotherapy
Meanwhile, the overwhelming success of the COVID-19 vaccines has focused attention on other ways of using mRNA to bolster the immune system against threats ranging from other infectious diseases to cancer.
The practicality of mRNA vaccines – relatively small quantities are required to induce an antibody response – coupled with their adaptable design, mean companies like Moderna are now targeting pathogens like Zika, chikungunya and cytomegalovirus, or CMV, which previously considered commercially unviable for vaccine developers. This is because outbreaks have been relatively sporadic, and these viruses mainly affect people in low-income nations who can't afford to pay premium prices for a vaccine. But mRNA technology means that jabs could be produced on a flexible basis, when required, at relatively low cost.
Other scientists suggest that mRNA could even provide a means of developing a universal influenza vaccine, a goal that's long been the Holy Grail for vaccinologists around the world.
"The mRNA technology allows you to pick out bits of the virus that you want to induce immunity to," says Michael Mulqueen, vice president of business development at eTheRNA, a Belgium-based biotech that's developing mRNA-based vaccines for malaria and HIV, as well as various forms of cancer. "This means you can get the immune system primed to the bits of the virus that don't vary so much between strains. So you could actually have a single vaccine that protects against a whole raft of different variants of the same virus, offering more universal coverage."
Before mRNA became synonymous with vaccines, its biggest potential was for cancer treatments. BioNTech, the German biotech company that collaborated with Pfizer to develop the first authorized COVID-19 vaccine, was initially founded to utilize mRNA for personalized cancer treatments, and the company remains interested in cancers ranging from melanoma to breast cancer.
One of the major hurdles in treating cancer has been the fact that tumors can look very different from one person to the next. It's why conventional approaches, such as chemotherapy or radiation, don't work for every patient. But weaponizing mRNA against cancer primes the immune cells with the tumor's specific genetic sequence, training the patient's body to attack their own unique type of cancer.
"It means you're able to think about personalizing cancer treatments down to specific subgroups of patients," says Mulqueen. "For example, eTheRNA are developing a renal cell carcinoma treatment which will be targeted at around 20% of these patients, who have specific tumor types. We're hoping to take that to human trials next year, but the challenge is trying to identify the right patients for the treatment at an early stage."
Repairing Damaged mRNA
While hopes are high that mRNA could usher in new cancer treatments and make CRISPR more accessible, a growing number of companies are also exploring an alternative to gene editing, known as RNA editing.
In genetic disorders, the mRNA in certain cells is impaired due to a rogue gene defect, and so the body ceases to produce a particular vital protein. Instead of permanently deleting the problem gene with CRISPR, the idea behind RNA editing is to inject small pieces of synthetic mRNA to repair the existing mRNA. Scientists think this approach will allow normal protein production to resume.
Over the past few years, this approach has gathered momentum, as some researchers have recognized that it holds certain key advantages over CRISPR. Companies from Belgium to Japan are now looking at RNA editing to treat all kinds of disorders, from Huntingdon's disease, to amyotrophic lateral sclerosis, or ALS, and certain types of cancer.
"With RNA editing, you don't need to make any changes to the DNA," explains Daniel de Boer, CEO of Dutch biotech ProQR, which is looking to treat rare genetic disorders that cause blindness. "Changes to the DNA are permanent, so if something goes wrong, that may not be desirable. With RNA editing, it's a temporary change, so we dose patients with our drugs once or twice a year."
Last month, ProQR reported a landmark case study, in which a patient with a rare form of blindness called Leber congenital amaurosis, which affects the retina at the back of the eye, recovered vision after three months of treatment.
"We have seen that this RNA therapy restores vision in people that were completely blind for a year or so," says de Boer. "They were able to see again, to read again. We think there are a large number of other genetic diseases we could go after with this technology. There are thousands of different mutations that can lead to blindness, and we think this technology can target approximately 25% of them."
Ultimately, there's likely to be a role for both RNA editing and CRISPR, depending on the disease. "I think CRISPR is ideally suited for illnesses where you would like to permanently correct a genetic defect," says Joshua Rosenthal of the Marine Biology Laboratory in Chicago. "Whereas RNA editing could be used to treat things like pain, where you might want to reset a neural circuit temporarily over a shorter period of time."
Much of this research has been accelerated by the COVID-19 pandemic, which has played a major role in bringing mRNA to the forefront of people's minds as a therapeutic.
"The pandemic has really shown that not only are mRNA approaches viable, they could in certain circumstances be vastly superior to more traditional technologies," says Mulqueen. "In the future, I would not be surprised if many of the top pharma products are mRNA derived."
Did researchers finally find a way to lick COVID?
A professor of medicine at the University of Michigan is researching whether lactoferrin, which is found in dairy products such as ice cream, can help to prevent COVID-19 infections.
Already vaccinated and want more protection from COVID-19? A protein found in ice cream could help, some research suggests, though there are a bunch of caveats.
The protein, called lactoferrin, is found in the milk of mammals and thus in dairy products, including ice cream. It has astounding antiviral properties that have been taken for granted and remain largely unexplored because it is a natural product, meaning that it cannot be patented and exploited by pharmaceutical companies.
Still, a few researchers in Europe and elsewhere have sought to better understand the compound.
Jonathan Sexton runs a drug screening program at the University of Michigan where cells are infected with a pathogen and then exposed to a library of the thousands of small molecule drug compounds – which can enter the body more easily than drugs with heavier molecules – approved by the FDA. In addition, the library includes compounds that passed phase 1 safety studies but later proved ineffective against the targeted disease. Each drug is dissolved in a solvent for exposure to the cells in the laborious testing process made feasible by robotic automation.
When COVID hit, researchers scrambled to identify any approved drug that might help fight the infection. Sexton decided to screen the drug library as well as some dietary supplements against SARS-CoV-2, the virus that causes the disease. Sexton says that the grunt work fell to Jesse Wotring, “a very talented PhD student,” who pulled lactoferrin off the shelf. But the regular solvent used in the testing process would destroy the protein, so he had to take another approach and do all the work by hand.
“We were agnostic,” says Sexton, who didn't have a strong interest in lactoferrin or any of the other compounds in the library, but the data was quite clear; lactoferrin “consistently produced the best efficacy...it was the absolute home run.” The findings were published in separate papers last year and in February.
It turns out that lactoferrin has several different mechanisms of action against SARS-CoV-2, inhibiting the virus from entering cells, moving around within them and replicating. Lactoferrin also modulates the overall immune response, which makes it difficult for the virus to simultaneously mutate resistance to the protein at every step of replication. “It has broad efficacy against every [SARS-CoV-2] variant that we've tested,” he says.
From bench to bedside
Sexton's initial interest was to develop a drug for the acute phase of COVID infection, to treat a hospitalized patient or prevent that hospitalization. But with the quick approval of vaccines and drugs to treat the disease, he increasingly focused on ways to better prevent infection and inhibit spread of the virus.
“If you can get lactoferrin to persist in your upper GI tract, then it may very well prevent the primary infection, and that's what we're really interested in.” He reasoned that a chewing gum formula might release enough lactoferrin into the mucosal tissue of the mouth and upper airways to inhibit replication and give the immune system a chance to knock out the virus before it can establish a foothold. It could also reduce the amount of virus spread through talking.
To get enough lactoferrin to have a possible beneficial effect, one would have to drink gallons of milk a day, “and that would have other undesirable consequences, like getting extremely obese,” says Sexton. Obesity is one of the leading risk factors for severe COVID disease.
Testing that theory has been difficult. The easiest way would be a “challenge trial,” where volunteers take the drug, or in this case gum, are exposed to the pathogen, and protection is measured. Some COVID challenge studies have been conducted in Europe but the FDA remains hesitant to allow such a study in the U.S. A traditional prevention study would be like a vaccine trial, involving thousands, perhaps tens of thousands of volunteers over a period of months or years, and it would be very expensive. No one has stepped forward to foot the bill.
So the next step for Sexton is a clinical trial of newly diagnosed COVID patients who will be given standard of care treatment, and layered on top of that they will receive either lactoferrin, probably in pill form, or a placebo. He has identified initial funding. “We would study their viral load over time as well as their symptoms.”
One issue the FDA is grappling with in considering the proposed trial is that it typically decides whether to approve drugs from a factory by applying a rigorous standard, called good manufacturing practices, while food products, which are the source of lactoferrin, are produced under somewhat different standards. The agency still has not finalized rules on how to deal with natural products used as drugs, such as fecal transplants, convalescent plasma, or medical marijuana.
Sexton is frustrated by the delay because lactoferrin derived from bovine milk whey has been used for many decades as a protein supplement by athletes, it is a large component of most infant formula, and the largest number of clinical studies of lactoferrin involve premature infants. There is no question of its safety, he says.
Do it yourself
So what can you do while waiting for regulatory wheels to spin and clinical trial data to be generated?
Could a dose of Ben & Jerry's provide some protection against SARS-CoV-2?
Sexton chuckles at the suggestion. He supposes it couldn't hurt. But to get enough lactoferrin to have a possible beneficial effect, one would have to drink gallons of milk a day, “and that would have other undesirable consequences, like getting extremely obese.” Obesity is one of the leading risk factors for severe COVID disease.
Pseudo-milk products made from soy, almonds, oats, or other plant products do not contain lactoferrin; it has to come from a teat. So that rules them out.
Whey-based protein shakes might be a useful way to add lactoferrin to the diet.
Probably the best option is to take conventional gelatin capsules of lactoferrin that are widely available wherever supplements are sold. Sexton calculates that about a gram a day, four 250 milligram capsules, should do it. He advises two in the morning and two a night. “You really want to take them on an empty stomach...your stomach treats [the lactoferrin protein] like it would a steak” and chops it for absorption in the intestine, which you do not want. About 70 percent of lactoferrin can get through an empty stomach, but eating food cranks up digestive gastric acids and the amount of intact lactoferrin that gets through to the gut plummets.
Sexton cautions, “We have not determined clinical efficacy yet,” and he is not offering advice as a physician, but in the spirit of harm reduction, he realizes that some people are going to try things that might help them. Lactoferrin “is remarkably safe. And so people have to make their own decisions about what they are willing to take and what they are not,” he says.
In today's episode, Leaps.org interviews Camila dos Santos, a molecular biologist at Cold Spring Harbor Lab, about her research on breasts and what makes them unique compared to any other part of the body.
My guest today for the Making Sense of Science podcast is Camila dos Santos, associate professor at Cold Spring Harbor Lab, who is a leading researcher of the inner lives of human mammary glands, more commonly known as breasts. These organs are unlike any other because throughout life they undergo numerous changes, first in puberty, then during pregnancies and lactation periods, and finally at the end of the cycle, when babies are weaned. A complex interplay of hormones governs these processes, in some cases increasing the risk of breast cancer and sometimes lowering it. Witnessing the molecular mechanics behind these processes in humans is not possible, so instead Dos Santos studies organoids—the clumps of breast cells donated by patients who undergo breast reduction surgeries or biopsies.
Show notes:
2:52 In response to hormones that arise during puberty, the breast cells grow and become more specialized, preparing the tissue for making milk.
7:53 How do breast cells know when to produce milk? It’s all governed by chemical messaging in the body. When the baby is born, the brain will release the hormone called oxytocin, which will make the breast cells contract and release the milk.
12:40 Breast resident immune cells are including T-cells and B-cells, but because they live inside the breast tissue their functions differ from the immune cells in other parts of the body,
17:00 With organoids—dimensional clumps of cells that are cultured in a dish—it is possible to visualize and study how these cells produce milk.
21:50 Women who are pregnant later in life are more likely to require medical intervention to breastfeed. Scientists are trying to understand the fundamental reasons why it happens.
26:10 Breast cancer has many risks factors. Generic mutations play a big role. All of us have the BRCA genes, but it is the alternation in the DNA sequence of the BRCA gene that can increase the predisposition to breast cancer. Aging and menopause are the risk factors for breast cancer, and so are pregnancies.
29:22 Women that are pregnant before the age of 20 to 25, have a decreased risk of breast cancer. And the hypothesis here is that during pregnancy breast cells more specialized, as specialized cells, they have a limited lifespan. It's more likely that they die before they turn into cancer.
33:08 Organoids are giving scientists an opportunity to practice personalized medicine. Scientists can test drugs on organoids taken from a patient to identify the most efficient treatment protocol.
Links:
Camila dos Santos’s Lab Page.
Editor's note: In addition to being a regular writer for Leaps.org, Lina Zeldovich is the guest host for today's episode of the Making Sense of Science podcast.
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.