Eric Kandel, 88, is a living legend. A specialist in the neurobiology of learning and memory, he received a Nobel Prize in 2000 for his work on the physiological basis of memory storage. Kandel is the Director of the Kavli Institute for Brain Science and Co-Director of the Mortimer B. Zuckerman Mind Brain Behavior Institute at Columbia University, where he has taught and conducted research for 44 years.
"If you walk two or three miles a day, you will release sufficient osteocalcin from your bones to combat non-Alzheimer's age-related memory loss."
And he's still going strong. Leapsmag Editor-in-Chief Kira Peikoff recently caught up with Dr. Kandel about his latest research, his advice for fellow seniors, and his opinions on some of the biggest challenges in neuroscience today.
What are working on these days?
I'm working on three problems: one is age-related memory loss, the second is post-traumatic stress disorder, and the third is the beholder's share: how a viewer responds to works of art. The beholder's share is a term that Alois Riegl created. He said there are two shares to a painting: the painter creates it, but it's not meaningful until somebody responds to it: the viewer, the beholder.
That's fascinating. As far as age-related memory loss, what are you learning in that area?
I'm learning that there are two forms of age-related memory loss. One is Alzheimer's disease, which we've known about for a long time. But the second is a more benign form which I call just age-related memory loss, which begins actually somewhat earlier and has a very different anatomical locus in the brain. It is caused by a different anatomical defect and responds to different therapeutic measures. It critically involves an area in the hippocampus called the dentate gyrus and it responds to a hormone released by bone called osteocalcin.
It therefore seems likely that one very effective way of combatting age-related memory loss is walking. If you walk two or three miles a day, you are likely to release sufficient osteocalcin from your bones to combat non-Alzheimer's age-related memory loss. In collaboration with Gerard Karsenty at Columbia, my lab at Columbia has been exploring this over the last year and a half.
Have you published anything about this yet?
We are just getting ready to do so.
"I think at the moment we should stick with trying to just reverse abnormalities."
Another question I have is about brain-computer interfaces to help cure disease or even provide cognitive enhancements. What do you think of companies like Kernel and Neuralink that are trying to push this new technology?
I think if it works it would be very nice. We have to see some direct evidence first, but it's certainly an encouraging approach. I think there are a number of directions we could take. The one I think at the moment is most profitable is to try to use the brain as it is and try to enhance it, restore it, refurbish it, make it function better from its age-related condition.
You mean, without some kind of machine interface?
Without necessarily introducing anything from the outside world. Although I have no objection whatsoever to introducing ancillary aids if they're beneficial and not harmful.
Do you have any opinion on whether neuroscience and technology should aim to provide an enhancement to the brain or just return it to baseline and cure disease?
I would be perfectly satisfied if we just cured diseases. I think at the moment we should stick with trying to just reverse abnormalities, but certainly … having the capability of becoming more intelligent, more attentive, capable of remembering things better than normal, that would be nice.
What do you think is the most important challenge facing the field of neuroscience today?
It's hard to say. I think the biology of consciousness is one fantastic problem. Trying to understand and successfully reverse some of the abnormalities of the brain, like age-related memory loss, schizophrenia, depression, manic depressive illness would be wonderful.
To be able to reverse memory loss, to allow people in their 70s, 80s, and 90s to live free and independent lives, is a major challenge for brain science.
Absolutely. Is there anything else you'd like to share with our readers about your research or the field more broadly?
I'd emphasize that brain science is a relatively young discipline but it's moving ahead in a very responsible and a very effective fashion, making progress in a number of areas, and is clearly sensitive to, and responsive to, the demands of the social situation. Right now, number one, the population is aging dramatically. In 1900, the average life expectancy was 50, and now the average life expectancy is 78 for men, and 82 for women.
So people are living longer and therefore are having age-related diseases, including memory loss. To be able to reverse it, to allow people in their 70s, 80s, and 90s to live free and independent lives, is a major challenge for brain science in both its basic and its clinically applied fashion. I think this is very important and serious effort should be put into this.
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 the two molecular components that make up CRISPR — a guide molecule and a cutting protein — to snip 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."
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."
"Making Sense of Science" is a monthly podcast that features interviews with leading medical and scientific experts about the latest developments and the big ethical and societal questions they raise. This episode is hosted by science and biotech journalist Emily Mullin, summer editor of the award-winning science outlet Leaps.org.