Genome Reading and Editing Tools for All
An open book representing the ability to read the human genome.
In 2006, the cover of Scientific American was "Know Your DNA" and the inside story was "Genomes for All." Today, we are closer to that goal than ever. Making it affordable for everyone to understand and change their DNA will fundamentally alter how we manage diseases, how we conduct clinical research, and even how we select a mate.
A frequent line of questions on the topic of making genome reading affordable is: Do we need to read the whole genome in order to accurately predict disease risk?
Since 2006, we have driven the cost of reading a human genome down from $3 billion to $600. To aid interpretation and research to produce new diagnostics and therapeutics, my research team at Harvard initiated the Personal Genome Project and later, Openhumans.org. This has demonstrated international informed consent for human genomes, and diverse environmental and trait data can be distributed freely. This is done with no strings attached in a manner analogous to Wikipedia. Cell lines from that project are similarly freely available for experiments on synthetic biology, gene therapy and human developmental biology. DNA from those cells have been chosen by the US National Institute of Standards and Technology and the Food and Drug Administration to be the key federal standards for the human genome.
A frequent line of questions on the topic of making genome reading affordable is: Do we need to read the whole genome in order to accurately predict disease risk? Can we just do most commonly varying parts of the genome, which constitute only a tiny fraction of a percent? Or just the most important parts encoding the proteins or 'exome,' which constitute about one percent of the genome? The commonly varying parts of the genome are poor predictors of serious genetic diseases and the exomes don't detect DNA rearrangements which often wipe out gene function when they occur in non-coding regions within genes. Since the cost of the exome is not one percent of the whole genome cost, but nearly identical ($600), missing an impactful category of mutants is really not worth it. So the answer is yes, we should read the whole genome to glean comprehensively meaningful information.
In parallel to the reading revolution, we have dropped the price of DNA synthesis by a similar million-fold and made genome editing tools close to free.
WRITING
In parallel to the reading revolution, we have dropped the price of DNA synthesis by a similar million-fold and made genome editing tools like CRISPR, TALE and MAGE close to free by distributing them through the non-profit Addgene.org. Gene therapies are already curing blindness in children and cancer in adults, and hopefully soon infectious diseases and hemoglobin diseases like sickle cell anemia. Nevertheless, gene therapies are (so far) the most expensive class of drugs in history (about $1 million dollars per dose).
This is in large part because the costs of proving safety and efficacy in a randomized clinical trial are high and that cost is spread out only over the people that benefit (aka the denominator). Striking growth is evident in such expensive hyper-personalized therapies ever since the "Orphan Drug Act of 1983." For the most common disease, aging (which kills 90 percent of people in wealthy regions of the world), the denominator is maximal and the cost of the drugs should be low as genetic interventions to combat aging become available in the next ten years. But what can we do about rarer diseases with cheap access to genome reading and editing tools? Try to prevent them in the first place.
A huge fraction of these births is preventable if unaffected carriers of such diseases do not mate.
ARITHMETIC
While the cost of reading has plummeted, the value of knowing your genome is higher than ever. About 5 percent of births result in extreme medical trauma over a person's lifetime due to rare genetic diseases. Even without gene therapy, these cost the family and society more than a million dollars in drugs, diagnostics and instruments, extra general care, loss of income for the affected individual and other family members, plus pain and anxiety of the "medical odyssey" often via dozens of mystified physicians. A huge fraction of these births is preventable if unaffected carriers of such diseases do not mate.
The non-profit genetic screening organization, Dor Yeshorim (established in 1983), has shown that this is feasible by testing for Tay–Sachs disease, Familial dysautonomia, Cystic fibrosis, Canavan disease, Glycogen storage disease (type 1), Fanconi anemia (type C), Bloom syndrome, Niemann–Pick disease, Mucolipidosis type IV. This is often done at the pre-marital, matchmaking phase, which can reduce the frequency of natural or induced abortions. Such matchmaking can be done in such a way that no one knows the carrier status of any individual in the system. In addition to those nine tests, many additional diseases can be picked up by whole genome sequencing. No person can know in advance that they are exempt from these risks.
Furthermore, concerns about rare "false positives" is far less at the stage of matchmaking than at the stage of prenatal testing, since the latter could involve termination of a healthy fetus, while the former just means that you restrict your dating to 90 percent of the population. In order to scale this up from 13 million Ashkenazim and Sephardim to billions in diverse cultures, we will likely see new computer security, encryption, blockchain and matchmaking tools.
Once the diseases are eradicated from our population, the interventions can be said to impact not only the current population, but all subsequent generations.
THE FUTURE
As reading and writing become exponentially more affordable and reliable, we can tackle equitable distribution, but there remain issues of education and security. Society, broadly (insurers, health care providers, governments) should be able to see a roughly 12-fold return on their investment of $1800 per person ($600 each for raw data, interpretation and incentivizing the participant) by saving $1 million per diseased child per 20 families. Everyone will have free access to their genome information and software to guide their choices in precision medicines, mates and participation in biomedical research studies.
In terms of writing and editing, if delivery efficiency and accuracy keep improving, then pill or aerosol formulations of gene therapies -- even non-prescription, veterinary or home-made versions -- are not inconceivable. Preventions tends to be more affordable and more humane than cures. If gene therapies provide prevention of diseases of aging, cancer and cognitive decline, they might be considered "enhancement," but not necessarily more remarkable than past preventative strategies, like vaccines against HPV-cancer, smallpox and polio. Whether we're overcoming an internal genetic flaw or an external infectious disease, the purpose is the same: to minimize human suffering. Once the diseases are eradicated from our population, the interventions can be said to impact not only the current population, but all subsequent generations. This reminds us that we need to listen carefully, educate each other and proactively imagine and deflect likely, and even unlikely, unintended consequences, including stigmatization of the last few unprotected individuals.
Gene Transfer Leads to Longer Life and Healthspan
In August, a study provided the first proof-of-principle that genetic material transferred from one species to another can increase both longevity and healthspan in the recipient animal.
The naked mole rat won’t win any beauty contests, but it could possibly win in the talent category. Its superpower: fighting the aging process to live several times longer than other animals its size, in a state of youthful vigor.
It’s believed that naked mole rats experience all the normal processes of wear and tear over their lifespan, but that they’re exceptionally good at repairing the damage from oxygen free radicals and the DNA errors that accumulate over time. Even though they possess genes that make them vulnerable to cancer, they rarely develop the disease, or any other age-related disease, for that matter. Naked mole rats are known to live for over 40 years without any signs of aging, whereas mice live on average about two years and are highly prone to cancer.
Now, these remarkable animals may be able to share their superpower with other species. In August, a study provided what may be the first proof-of-principle that genetic material transferred from one species can increase both longevity and healthspan in a recipient animal.
There are several theories to explain the naked mole rat’s longevity, but the one explored in the study, published in Nature, is based on the abundance of large-molecule high-molecular mass hyaluronic acid (HMM-HA).
A small molecule version of hyaluronic acid is commonly added to skin moisturizers and cosmetics that are marketed as ways to keep skin youthful, but this version, just applied to the skin, won’t have a dramatic anti-aging effect. The naked mole rat has an abundance of the much-larger molecule, HMM-HA, in the chemical-rich solution between cells throughout its body. But does the HMM-HA actually govern the extraordinary longevity and healthspan of the naked mole rat?
To answer this question, Dr. Vera Gorbunova, a professor of biology and oncology at the University of Rochester, and her team created a mouse model containing the naked mole rat gene hyaluronic acid synthase 2, or nmrHas2. It turned out that the mice receiving this gene during their early developmental stage also expressed HMM-HA.
The researchers found that the effects of the HMM-HA molecule in the mice were marked and diverse, exceeding the expectations of the study’s co-authors. High-molecular mass hyaluronic acid was more abundant in kidneys, muscles and other organs of the Has2 mice compared to control mice.
In addition, the altered mice had a much lower incidence of cancer. Seventy percent of the control mice eventually developed cancer, compared to only 57 percent of the altered mice, even after several techniques were used to induce the disease. The biggest difference occurred in the oldest mice, where the cancer incidence for the Has2 mice and the controls was 47 percent and 83 percent, respectively.
With regard to longevity, Has2 males increased their lifespan by more than 16 percent and the females added 9 percent. “Somehow the effect is much more pronounced in male mice, and we don’t have a perfect answer as to why,” says Dr. Gorbunova. Another improvement was in the healthspan of the altered mice: the number of years they spent in a state of relative youth. There’s a frailty index for mice, which includes body weight, mobility, grip strength, vision and hearing, in addition to overall conditions such as the health of the coat and body temperature. The Has2 mice scored lower in frailty than the controls by all measures. They also performed better in tests of locomotion and coordination, and in bone density.
Gorbunova’s results show that a gene artificially transferred from one species can have a beneficial effect on another species for longevity, something that had never been demonstrated before. This finding is “quite spectacular,” said Steven Austad, a biologist at the University of Alabama at Birmingham, who was not involved in the study.
Just as in lifespan, the effects in various organs and systems varied between the sexes, a common occurrence in longevity research, according to Austad, who authored the book Methuselah’s Zoo and specializes in the biological differences between species. “We have ten drugs that we can give to mice to make them live longer,” he says, “and all of them work better in one sex than in the other.” This suggests that more attention needs to be paid to the different effects of anti-aging strategies between the sexes, as well as gender differences in healthspan.
According to the study authors, the HMM-HA molecule delivered these benefits by reducing inflammation and senescence (cell dysfunction and death). The molecule also caused a variety of other benefits, including an upregulation of genes involved in the function of mitochondria, the powerhouses of the cells. These mechanisms are implicated in the aging process, and in human disease. In humans, virtually all noncommunicable diseases entail an acceleration of the aging process.
So, would the gene that creates HMM-HA have similar benefits for longevity in humans? “We think about these questions a lot,” Gorbunova says. “It’s been done by injections in certain patients, but it has a local effect in the treatment of organs affected by disease,” which could offer some benefits, she added.
“Mice are very short-lived and cancer-prone, and the effects are small,” says Steven Austad, a biologist at the University of Alabama at Birmingham. “But they did live longer and stay healthy longer, which is remarkable.”
As for a gene therapy to introduce the nmrHas2 gene into humans to obtain a global result, she’s skeptical because of the complexity involved. Gorbunova notes that there are potential dangers in introducing an animal gene into humans, such as immune responses or allergic reactions.
Austad is equally cautious about a gene therapy. “What this study says is that you can take something a species does well and transfer at least some of that into a new species. It opens up the way, but you may need to transfer six or eight or ten genes into a human” to get the large effect desired. Humans are much more complex and contain many more genes than mice, and all systems in a biological organism are intricately connected. One naked mole rat gene may not make a big difference when it interacts with human genes, metabolism and physiology.
Still, Austad thinks the possibilities are tantalizing. “Mice are very short-lived and cancer-prone, and the effects are small,” he says. “But they did live longer and stay healthy longer, which is remarkable.”
As for further research, says Austad, “The first place to look is the skin” to see if the nmrHas2 gene and the HMM-HA it produces can reduce the chance of cancer. Austad added that it would be straightforward to use the gene to try to prevent cancer in skin cells in a dish to see if it prevents cancer. It would not be hard to do. “We don’t know of any downsides to hyaluronic acid in skin, because it’s already used in skin products, and you could look at this fairly quickly.”
“Aging mechanisms evolved over a long time,” says Gorbunova, “so in aging there are multiple mechanisms working together that affect each other.” All of these processes could play a part and almost certainly differ from one species to the next.
“HMM-HA molecules are large, but we’re now looking for a small-molecule drug that would slow it’s breakdown,” she says. “And we’re looking for inhibitors, now being tested in mice, that would hinder the breakdown of hyaluronic acid.” Gorbunova has found a natural, plant-based product that acts as an inhibitor and could potentially be taken as a supplement. Ultimately, though, she thinks that drug development will be the safest and most effective approach to delivering HMM-HA for anti-aging.
A new study provides key insights in what causes Alzheimer's: a breakdown in the brain’s system for clearing waste.
In recent years, researchers of Alzheimer’s have made progress in figuring out the complex factors that lead to the disease. Yet, the root cause, or causes, of Alzheimer’s are still pretty much a mystery.
In fact, many people get Alzheimer’s even though they lack the gene variant we know can play a role in the disease. This is a critical knowledge gap for research to address because the vast majority of Alzheimer’s patients don’t have this variant.
A new study provides key insights into what’s causing the disease. The research, published in Nature Communications, points to a breakdown over time in the brain’s system for clearing waste, an issue that seems to happen in some people as they get older.
Michael Glickman, a biologist at Technion – Israel Institute of Technology, helped lead this research. I asked him to tell me about his approach to studying how this breakdown occurs in the brain, and how he tested a treatment that has potential to fix the problem at its earliest stages.
Dr. Michael Glickman is internationally renowned for his research on the ubiquitin-proteasome system (UPS), the brain's system for clearing the waste that is involved in diseases such as Huntington's, Alzheimer's, and Parkinson's. He is the head of the Lab for Protein Characterization in the Faculty of Biology at the Technion – Israel Institute of Technology. In the lab, Michael and his team focus on protein recycling and the ubiquitin-proteasome system, which protects against serious diseases like Alzheimer’s, Parkinson’s, cystic fibrosis, and diabetes. After earning his PhD at the University of California at Berkeley in 1994, Michael joined the Technion as a Senior Lecturer in 1998 and has served as a full professor since 2009.
Dr. Michael Glickman