osteoarthritis
Could CRISPR Gene-Editing Technology Be an Answer to Chronic Pain?
Posted on by Dr. Francis Collins
Gene editing has shown great promise as a non-heritable way to treat a wide range of conditions, including many genetic diseases and more recently, even COVID-19. But could a version of the CRISPR gene-editing tool also help deliver long-lasting pain relief without the risk of addiction associated with prescription opioid drugs?
In work recently published in the journal Science Translational Medicine, researchers demonstrated in mice that a modified version of the CRISPR system can be used to “turn off” a gene in critical neurons to block the transmission of pain signals [1]. While much more study is needed and the approach is still far from being tested in people, the findings suggest that this new CRISPR-based strategy could form the basis for a whole new way to manage chronic pain.
This novel approach to treating chronic pain occurred to Ana Moreno, the study’s first author, when she was a Ph.D. student in the NIH-supported lab of Prashant Mali, University of California, San Diego. Mali had been studying a wide range of novel gene- and cell-based therapeutics. While reading up on both, Moreno landed on a paper about a mutation in a gene that encodes a pain-enhancing protein in spinal neurons called NaV1.7.
Moreno read that kids born with a loss-of-function mutation in this gene have a rare condition known as congenital insensitivity to pain (CIP). They literally don’t sense and respond to pain. Although these children often fail to recognize serious injuries because of the absence of pain to alert them, they have no other noticeable physical effects of the condition.
For Moreno, something clicked. What if it were possible to engineer a new kind of treatment—one designed to turn this gene down or fully off and stop people from feeling chronic pain?
Moreno also had an idea about how to do it. She’d been working on repressing or “turning off” genes using a version of CRISPR known as “dead” Cas9 [2]. In CRISPR systems designed to edit DNA, the Cas9 enzyme is often likened to a pair of scissors. Its job is to cut DNA in just the right spot with the help of an RNA guide. However, CRISPR-dead Cas9 no longer has any ability to cut DNA. It simply sticks to its gene target and blocks its expression. Another advantage is that the system won’t lead to any permanent DNA changes, since any treatment based on CRISPR-dead Cas9 might be safely reversed.
After establishing that the technique worked in cells, Moreno and colleagues moved to studies of laboratory mice. They injected viral vectors carrying the CRISPR treatment into mice with different types of chronic pain, including inflammatory and chemotherapy-induced pain.
Moreno and colleagues determined that all the mice showed evidence of durable pain relief. Remarkably, the treatment also lasted for three months or more and, importantly, without any signs of side effects. The researchers are also exploring another approach to do the same thing using a different set of editing tools called zinc finger nucleases (ZFNs).
The researchers say that one of these approaches might one day work for people with a large number of chronic pain conditions that involve transmission of the pain signal through NaV1.7. That includes diabetic polyneuropathy, sciatica, and osteoarthritis. It also could provide relief for patients undergoing chemotherapy, along with those suffering from many other conditions. Moreno and Mali have co-founded the spinoff company Navega Therapeutics, San Diego, CA, to work on the preclinical steps necessary to help move their approach closer to the clinic.
Chronic pain is a devastating public health problem. While opioids are effective for acute pain, they can do more harm than good for many chronic pain conditions, and they are responsible for a nationwide crisis of addiction and drug overdose deaths [3]. We cannot solve any of these problems without finding new ways to treat chronic pain. As we look to the future, it’s hopeful that innovative new therapeutics such as this gene-editing system could one day help to bring much needed relief.
References:
[1] Long-lasting analgesia via targeted in situ repression of NaV1.7 in mice. Moreno AM, Alemán F, Catroli GF, Hunt M, Hu M, Dailamy A, Pla A, Woller SA, Palmer N, Parekh U, McDonald D, Roberts AJ, Goodwill V, Dryden I, Hevner RF, Delay L, Gonçalves Dos Santos G, Yaksh TL, Mali P. Sci Transl Med. 2021 Mar 10;13(584):eaay9056.
[2] Nuclease dead Cas9 is a programmable roadblock for DNA replication. Whinn KS, Kaur G, Lewis JS, Schauer GD, Mueller SH, Jergic S, Maynard H, Gan ZY, Naganbabu M, Bruchez MP, O’Donnell ME, Dixon NE, van Oijen AM, Ghodke H. Sci Rep. 2019 Sep 16;9(1):13292.
[3] Drug Overdose Deaths. Centers for Disease Control and Prevention.
Links:
Congenital insensitivity to pain (National Center for Advancing Translational Sciences/NIH)
Opioids (National Institute on Drug Abuse/NIH)
Mali Lab (University of California, San Diego)
Navega Therapeutics (San Diego, CA)
NIH Support: National Human Genome Research Institute; National Cancer Institute; National Institute of General Medical Sciences; National Institute of Neurological Disorders and Stroke
Aging Research: Blood Proteins Show Your Age
Posted on by Dr. Francis Collins
How can you tell how old someone is? Of course, you could scan their driver’s license or look for signs of facial wrinkles and gray hair. But, as researchers just found in a new study, you also could get pretty close to the answer by doing a blood test.
That may seem surprising. But in a recent study in Nature Medicine, an NIH-funded research team was able to gauge a person’s age quite reliably by analyzing a blood sample for levels of a few hundred proteins. The results offer important new insights into what happens as we age. For example, the team suggests that the biological aging process isn’t steady and appears to accelerate periodically—with the greatest bursts coming, on average, around ages 34, 60, and 78.
These findings indicate that it may be possible one day to devise a blood test to identify individuals who are aging faster biologically than others. Such folks might be at risk earlier in life for cardiovascular problems, Alzheimer’s disease, osteoarthritis, and other age-related health issues.
What’s more, this work raises hope for interventions that may slow down the “proteomic clock” and perhaps help to keep people biologically younger than their chronological age. Such a scenario might sound like pure fantasy, but this same group of researchers showed a few years ago that it’s indeed possible to rejuvenate an older mouse by infusing blood from a much younger mouse.
Those and other earlier findings from the lab of Tony Wyss-Coray, Stanford School of Medicine, Palo Alto, CA, raised the tantalizing possibility that certain substances in young blood can revitalize the aging brain and other parts of the body. In search of additional clues in the new study, the Wyss-Coray team tracked how the protein composition of blood changes as people age.
To find those clues, they isolated plasma from more than 4,200 healthy individuals between ages 18 and 95. The researchers then used data from more than half of the participants to assemble a “proteomic clock” of aging. Within certain limits, the clock could accurately predict the chronological age of the study’s remaining 1,446 participants. The best predictions relied on just 373 of the clock’s almost 3,000 proteins.
As further validation, the clock also reliably predicted the correct chronological age of four groups of people not in the study. Interestingly, it was possible to make a decent age prediction based on just nine of the clock’s most informative proteins.
The findings show that telltale proteomic changes arise with age, and they likely have important and as-yet unknown health implications. After all, those proteins found circulating in the bloodstream come not just from blood cells but also from cells throughout the body. Intriguingly, the researchers report that people who appeared biologically younger than their actual chronological age based on their blood proteins also performed better on cognitive and physical tests.
Most of us view aging as a gradual, linear process. However, the protein evidence suggests that, biologically, aging follows a more complex pattern. Some proteins did gradually tick up or down over time in an almost linear fashion. But the levels of many other proteins rose or fell more markedly over time. For instance, one neural protein in the blood stayed constant until around age 60, when its levels spiked. Why that is so remains to be determined.
As noted, the researchers found evidence that the aging process includes a series of three bursts. Wyss-Coray said he found it especially interesting that the first burst happens in early mid-life, around age 34, well before common signs of aging and its associated health problems would manifest.
It’s also well known that men and women age differently, and this study adds to that evidence. About two-thirds of the proteins that changed with age also differed between the sexes. However, because the effect of aging on the most important proteins of the clock is much stronger than the differences in gender, the proteomic clock still could accurately predict the ages in all people.
Overall, the findings show that protein substances in blood can serve as a useful measure of a person’s chronological and biological age and—together with Wyss-Coray’s earlier studies—that substances in blood may play an active role in the aging process. Wyss-Coray reports that his team continues to dig deeper into its data, hoping to learn more about the origins of particular proteins in the bloodstream, what they mean for our health, and how to potentially turn back the proteomic clock.
Reference:
[1] Undulating changes in human plasma proteome profiles across the lifespan. Lehallier B, Gate D, Schaum N, Nanasi T, Lee SE, Yousef H, Moran Losada P, Berdnik D, Keller A, Verghese J, Sathyan S, Franceschi C, Milman S, Barzilai N, Wyss-Coray T. Nat Med. 2019 Dec;25(12):1843-1850.
Links:
What Do We Know About Healthy Aging? (National Institute on Aging/NIH)
Cognitive Health (NIA)
Wyss-Coray Lab (Stanford University, Palo Alto, CA)
NIH Support: National Institute on Aging
Happy New Year: Looking Back at 2016 Research Highlights
Posted on by Dr. Francis Collins
Happy New Year! While everyone was busy getting ready for the holidays, the journal Science announced its annual compendium of scientific Breakthroughs of the Year. If you missed it, the winner for 2016 was the detection of gravitational waves—tiny ripples in the fabric of spacetime created by the collision of two black holes 1.3 billion years ago! It’s an incredible discovery, and one that Albert Einstein predicted a century ago.
Among the nine other advances that made the first cut for Breakthrough of the Year, several involved the biomedical sciences. As I’ve done in previous years (here and here), I’ll kick off this New Year by taking a quick look of some of the breakthroughs that directly involved NIH support:
Cool Videos: Better Computation, Better Hope for Movement Disorders
Posted on by Dr. Francis Collins
Avatar. Pick your Sim. The entertainment world has done an amazing job developing software that generates animated characters with strikingly realistic movement. But scientists have taken this one step further to create models that can help kids with cerebral palsy walk better, delay the onset of osteoarthritis, and even answer a question in the minds of children of all ages: How exactly did T. rex run?
That’s what the researchers behind this video—an entrant in the NIH Common Fund’s recent video competition—have done. They’ve developed OpenSim: a free software tool that combines state-of-the-art musculoskeletal modeling and dynamic computer simulations to produce highly accurate representations of the underlying biomechanics of motion. OpenSim was designed at the NIH-supported center for physics-based Simulation of Biological Structures (Simbios) at Stanford University, Palo Alto, CA. And now, researchers around the world are using OpenSim to find more effective interventions for a variety of movement disorders.
Links:
NIH Common Fund Video Competition
OpenSim (Stanford University, Palo Alto, CA)
NIH Support: Common Fund; Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Institute for General Medical Sciences
LabTV: Curious about Post-Traumatic Osteoarthritis
Posted on by Dr. Francis Collins
If you like sports and you like science, I think you’ll enjoy meeting Avery White, an undergraduate studying biomedical engineering at the University of Delaware in Newark. In this LabTV profile, we catch up with White as she conducts basic research that may help us better understand—and possibly prevent—the painful osteoarthritis that often pops up years after knee injuries from sports and other activities.
Many athletes, along with lots of regular folks, are familiar with the immediate and painful consequences of tearing the knee’s cartilage (meniscus) or anterior cruciate ligament (ACL). Most also know that such injuries can usually be repaired by surgery. Yet, many people aren’t aware of the longer-term health threat posed by ACL and meniscus tears: a substantially increased risk of developing osteoarthritis years down the road—in some individuals, even as early as age 30. While treatments are available for such post-traumatic osteoarthritis, including physical therapy, pain medications, and even knee-replacement surgery, more preventive options are needed to avoid these chronic joint problems.
White’s interest in this problem is personal. She’s a volleyball player herself, her sister tore her ACL, and her mother damaged her meniscus. After spending a summer working in a lab, this Wilmington, DE native has grown increasingly interested in the field of tissue engineering. She says it offers her an opportunity to use “micro” cell biology techniques to address a “macro” challenge: finding ways to encourage the body to generate healthy new cells that may prevent or reverse injury-induced osteoarthritis.
What’s up next for White? She says maybe a summer internship in a lab overseas, and, on the more distant horizon, graduate school with the goal of earning a Ph.D.
Links:
University of Delaware Biomedical Engineering
Science Careers (National Institute of General Medical Sciences/NIH)
Careers Blog (Office of Intramural Training/NIH)
Reprogramming Genes to Keep Joints Healthy
Posted on by Dr. Francis Collins
![Caption: [Left] The knee joint of a normal mouse that endured an ACL-type injury. The injury triggered osteoarthritis and caused the cartilage on the femur (red) and tibia (green) to degrade, allowing the bones to sandwich together. [Right] This is the knee joint of a mouse that received gene therapy after the ACL injury. The cartilage is thick and healthy, and covers the bones completely, providing a cushion.](http://directorsblog.nih.gov/wp-content/uploads/2013/03/mouse-knee-joints.jpg)
Baylor College of Medicine, Houston, TX
Our joints are pretty amazing marvels of engineering, but they don’t last forever. As we age, or if we suffer certain injuries, the smooth, slippery white cartilage covering the ends of our bones begins to fray and degrade. This causes osteoarthritis (OA), or ‘wear-and-tear’ arthritis. As the cartilage thins and disappears, the bones can even grow spurs that grate against each other, causing swelling and pain. It’s a major cause of disability, and there’s currently no cure—other than joint replacement, which is a pretty big deal and isn’t available for all joints. About 27 million Americans already have osteoarthritis; about 1 in 2 will suffer from some form of the disease over their lifetime. Those are lousy odds.
