The First Cloned Monkeys Provoked More Shrugs Than Shocks
Zhong Zhong and Hua Hua, the two cloned macaques.
A few months ago, it was announced that not one, but two healthy long-tailed macaque monkeys were cloned—a first for primates of any kind. The cells were sourced from aborted monkey fetuses and the DNA transferred into eggs whose nuclei had been removed, the same method that was used in 1996 to clone "Dolly the Sheep." Two live births, females named Zhong Zhong and Hua Hua, resulted from 60 surrogate mothers. Inefficient, it's true. But over time, the methods are likely to be improved.
The scientist who supervised the project predicts that cloning, along with gene editing, will result in "ideal primate models" for studying disease mechanisms and drug screening.
Dr. Gerald Schatten, a famous would-be monkey cloner, authored a controversial paper in 2003 describing the formidable challenges to cloning monkeys and humans, speculating that the feat might never be accomplished. Now, some 15 years later, that prediction, insofar as it relates to monkeys, has blown away.
Zhong Zhong and Hua Hua were created at the Chinese Academy of Science's Institute of Neuroscience in Shanghai. The Institute founded in 1999 boasts 32 laboratories, expanding to 50 labs in 2020. It maintains two non-human primate research facilities.
The founder and director, Dr. Mu-ming Poo, supervised the project. Poo is an extremely accomplished senior researcher at the pinnacle of his field, a distinguished professor emeritus in Biology at UC Berkeley. In 2016, he was awarded the prestigious $500,000 Gruber Neuroscience Prize. At that time, Poo's experiments were described by a colleague as being "innovative and very often ingenious."
Poo maintains the reputation of studying some of the most important questions in cellular neuroscience.
But is society ready to accept cloned primates for medical research without the attendant hysteria about fears of cloned humans?
By Western standards, use of non-human primates in research focuses on the welfare of the animal subjects. As PETA reminds us, there is a dreadful and sad history of mistreatment. Dr. Poo assures us that his cloned monkeys are treated ethically and that the Institute is compliant with the highest regulatory standards, as promulgated by the U.S. National Institutes of Health.
He presents the noblest justifications for the research. He predicts that cloning, along with gene editing, will result in "ideal primate models" for studying disease mechanisms and drug screening. He declares that this will eventually help to solve Parkinson's, Huntington's and Alzheimer's disease.
But is society ready to accept cloned primates for medical research without the attendant hysteria about fears of cloned humans? It appears so.
While much of the news coverage expressed this predictable worry, my overall impression is that the societal response was muted. Where was the expected outrage? Then again, we've come a long way since Dolly the Sheep in terms of both the science and the cultural acceptance of cloning. Perhaps my unique vantage point can provide perspective on how much attitudes have evolved.
Perhaps my unique vantage point can provide perspective on how much attitudes have evolved.
I sometimes joke that I am the world's only human cloning lawyer—a great gig but there are still no clients.
I first crashed into the cloning scene in 2002 when I sued the so-called human cloning company "Clonaid" and asked in court to have a temporary guardian appointed for the alleged first human clone "Baby Eve." The claim needed to be tested, and mine was the first case ever aiming to protect the rights of a human clone. My legal basis was child welfare law, protecting minors from abuse, negligence, and exploitation.
The case had me on back-to-back global television broadcasts around the world; there was live news and "breathless" coverage at the courthouse emblazoned in headlines in every language on the planet. Cloning was, after all, perceived as a species-altering event: asexual reproduction. The controversy dominated world headlines for month until Clonaid's claim was busted as the "fakest" of fake news.
Fresh off the cloning case, the scientific community reached out to me, seeing me as the defender of legitimate science, an opponent of cloning human babies but a proponent of using cloning techniques to accelerate ethical regenerative medicine and embryonic stem cell research in general.
The years 2003 to 2006 were the era of the "stem cell wars" and a dominant issue was human cloning. Social conservative lawmakers around the world were seeking bans or criminalization not only of cloning babies but also the cloning of cells to match the donor's genetics. Scientists were being threatened with fines and imprisonment. Human cloning was being challenged in the United Nations with the United States backing a global treaty to ban and morally condemn all cloning -- including the technique that was crucial for research.
Scientists and patients were touting the cloning technique as a major biomedical breakthrough because cells could be created as direct genetic matches from a specific donor.
At the same time, scientists and patients were touting the cloning technique as a major biomedical breakthrough because cells could be created as direct genetic matches from a specific donor.
So my organization organized a conference at UN headquarters to defend research cloning and all the big names in stem cell research were there. We organized petitions to the UN and faxed 35,000 signatures to the country mission. These ongoing public policy battles were exacerbated in part because of the growing fear that cloning babies was just around the corner.
Then in 2005, the first cloned dog stunned the world, an Afghan hound named Snuppy. I met him when I visited the laboratories of Professor Woo Suk Hwang in Korea. His minders let me hold his leash -- TIME magazine's scientific breakthrough of the year. He didn't lick me or even wag his tail; I figured he must not like lawyers.
Tragically, soon thereafter, I witnessed firsthand Dr. Hwang's fall from grace when his human stem cell cloning breakthroughs proved false. The massive scientific misconduct rocked the nation of Korea, stem cell science in general, and provoked terrible news coverage.
Nevertheless, by 2007, the proposed bans lost steam, overridden by the advent of a Japanese researcher's Nobel Prize winning formula for reprogramming human cells to create genetically matched cell lines, not requiring the destruction of human embryos.
After years of panic, none of the recent cloning headlines has caused much of a stir.
Five years later, when two American scientists accomplished therapeutic human cloned stem cell lines, their news was accepted without hysteria. Perhaps enough time had passed since Hwang and the drama was drained.
In the just past 30 days we have seen more cloning headlines. Another cultural icon, Barbara Streisand, revealed she owns two cloned Coton de Tulear puppies. The other weekend, the television news show "60 Minutes" devoted close to an hour on the cloned ponies used at the top level of professional polo. And in India, scientists just cloned the first Assamese buffalo.
And you know what? After years of panic, none of this has caused much of a stir. It's as if the future described by Alvin Toffler in "Future Shock" has arrived and we are just living with it. A couple of cloned monkeys barely move the needle.
Perhaps it is the advent of the Internet and the overall dilution of wonder and outrage. Or maybe the muted response is rooted in popular culture. From Orphan Black to the plotlines of dozens of shows and books, cloning is just old news. The hand-wringing discussions about "human dignity" and "slippery slopes" have taken a backseat to the AI apocalypse and Martian missions.
We humans are enduring plagues of dementia and Alzheimer's, and we will need more monkeys. I will take mine cloned, if it will speed progress.
Personally, I still believe that cloned children should not be an option. Child welfare laws might be the best deterrent.
The same does not hold for cloning monkey research subjects. Squeamishness aside, I think Zhong Zhong and Hua Hua will soon be joined by a legion of cloned macaques and probably marmosets.
We humans are enduring plagues of dementia and Alzheimer's, and we will need more monkeys. I will take mine cloned, if it will speed the mending of these consciousness-destroying afflictions.
Scientific revolutions once took centuries, then decades, and now seem to bombard us daily. The convergence of technologies has accelerated the future. To Zhong Zhong and Hua Hua, my best wishes with the hope that their sacrifices will contribute to the health of all primates -- not just humans.
Scientists Are Growing an Edible Cholera Vaccine in Rice
The world's attention has been focused on the coronavirus crisis but Yemen, Bangladesh and many others countries in Asia and Africa are also in the grips of another pandemic: cholera. The current cholera pandemic first emerged in the 1970s and has devastated many communities in low-income countries. Each year, cholera is responsible for an estimated 1.3 million to 4 million cases and 21,000 to 143,000 deaths worldwide.
Immunologist Hiroshi Kiyono and his team at the University of Tokyo hope they can be part of the solution: They're making a cholera vaccine out of rice.
"It is much less expensive than a traditional vaccine, by a long shot."
Cholera is caused by eating food or drinking water that's contaminated by the feces of a person infected with the cholera bacteria, Vibrio cholerae. The bacteria produces the cholera toxin in the intestines, leading to vomiting, diarrhea and severe dehydration. Cholera can kill within hours of infection if it if's not treated quickly.
Current cholera vaccines are mainly oral. The most common oral are given in two doses and are made out of animal or insect cells that are infected with killed or weakened cholera bacteria. Dukoral also includes cells infected with CTB, a non-harmful part of the cholera toxin. Scientists grow cells containing the cholera bacteria and the CTB in bioreactors, large tanks in which conditions can be carefully controlled.
These cholera vaccines offer moderate protection but it wears off relatively quickly. Cold storage can also be an issue. The most common oral vaccines can be stored at room temperature but only for 14 days.
"Current vaccines confer around 60% efficacy over five years post-vaccination," says Lucy Breakwell, who leads the U.S. Centers for Disease Control and Prevention's cholera work within Global Immunization Division. Given the limited protection, refrigeration issue, and the fact that current oral vaccines require two disease, delivery of cholera vaccines in a campaign or emergency setting can be challenging. "There is a need to develop and test new vaccines to improve public health response to cholera outbreaks."
A New Kind of Vaccine
Kiyono and scientists at Tokyo University are creating a new, plant-based cholera vaccine dubbed MucoRice-CTB. The researchers genetically modify rice so that it contains CTB, a non-harmful part of the cholera toxin. The rice is crushed into a powder, mixed with saline solution and then drunk. The digestive tract is lined with mucosal membranes which contain the mucosal immune system. The mucosal immune system gets trained to recognize the cholera toxin as the rice passes through the intestines.
The cholera toxin has two main parts: the A subunit, which is harmful, and the B subunit, also known as CTB, which is nontoxic but allows the cholera bacteria to attach to gut cells. By inducing CTB-specific antibodies, "we might be able to block the binding of the vaccine toxin to gut cells, leading to the prevention of the toxin causing diarrhea," Kiyono says.
Kiyono studies the immune responses that occur at mucosal membranes across the body. He chose to focus on cholera because he wanted to replicate the way traditional vaccines work to get mucosal membranes in the digestive tract to produce an immune response. The difference is that his team is creating a food-based vaccine to induce this immune response. They are also solely focusing on getting the vaccine to induce antibodies for the cholera toxin. Since the cholera toxin is responsible for bacteria sticking to gut cells, the hope is that they can stop this process by producing antibodies for the cholera toxin. Current cholera vaccines target the cholera bacteria or both the bacteria and the toxin.
David Pascual, an expert in infectious diseases and immunology at the University of Florida, thinks that the MucoRice vaccine has huge promise. "I truly believe that the development of a food-based vaccine can be effective. CTB has a natural affinity for sampling cells in the gut to adhere, be processed, and then stimulate our immune system, he says. "In addition to vaccinating the gut, MucoRice has the potential to touch other mucosal surfaces in the mouth, which can help generate an immune response locally in the mouth and distally in the gut."
Cost Effectiveness
Kiyono says the MucoRice vaccine is much cheaper to produce than a traditional vaccine. Current vaccines need expensive bioreactors to grow cell cultures under very controlled, sterile conditions. This makes them expensive to manufacture, as different types of cell cultures need to be grown in separate buildings to avoid any chance of contamination. MucoRice doesn't require such an expensive manufacturing process because the rice plants themselves act as bioreactors.
The MucoRice vaccine also doesn't require the high cost of cold storage. It can be stored at room temperature for up to three years unlike traditional vaccines. "Plant-based vaccine development platforms present an exciting tool to reduce vaccine manufacturing costs, expand vaccine shelf life, and remove refrigeration requirements, all of which are factors that can limit vaccine supply and accessibility," Breakwell says.
Kathleen Hefferon, a microbiologist at Cornell University agrees. "It is much less expensive than a traditional vaccine, by a long shot," she says. "The fact that it is made in rice means the vaccine can be stored for long periods on the shelf, without losing its activity."
A plant-based vaccine may even be able to address vaccine hesitancy, which has become a growing problem in recent years. Hefferon suggests that "using well-known food plants may serve to reduce the anxiety of some vaccine hesitant people."
Challenges of Plant Vaccines
Despite their advantages, no plant-based vaccines have been commercialized for human use. There are a number of reasons for this, ranging from the potential for too much variation in plants to the lack of facilities large enough to grow crops that comply with good manufacturing practices. Several plant vaccines for diseases like HIV and COVID-19 are in development, but they're still in early stages.
In developing the MucoRice vaccine, scientists at the University of Tokyo have tried to overcome some of the problems with plant vaccines. They've created a closed facility where they can grow rice plants directly in nutrient-rich water rather than soil. This ensures they can grow crops all year round in a space that satisfies regulations. There's also less chance for variation since the environment is tightly controlled.
Clinical Trials and Beyond
After successfully growing rice plants containing the vaccine, the team carried out their first clinical trial. It was completed early this year. Thirty participants received a placebo and 30 received the vaccine. They were all Japanese men between the ages of 20 and 40 years old. 60 percent produced antibodies against the cholera toxin with no side effects. It was a promising result. However, there are still some issues Kiyono's team need to address.
The vaccine may not provide enough protection on its own. The antigen in any vaccine is the substance it contains to induce an immune response. For the MucoRice vaccine, the antigen is not the cholera bacteria itself but the cholera toxin the bacteria produces.
"The development of the antigen in rice is innovative," says David Sack, a professor at John Hopkins University and expert in cholera vaccine development. "But antibodies against only the toxin have not been very protective. The major protective antigen is thought to be the LPS." LPS, or lipopolysaccharide, is a component of the outer wall of the cholera bacteria that plays an important role in eliciting an immune response.
The Japanese team is considering getting the rice to also express the O antigen, a core part of the LPS. Further investigation and clinical trials will look into improving the vaccine's efficacy.
Beyond cholera, Kiyono hopes that the vaccine platform could one day be used to make cost-effective vaccines for other pathogens, such as norovirus or coronavirus.
"We believe the MucoRice system may become a new generation of vaccine production, storage, and delivery system."
An Investigational Drug Offers Hope to Patients with a Disabling Neuromuscular Disease
Robert Thomas was a devoted runner, gym goer, and crew member on a sailing team in San Diego when, in his 40s, he noticed that his range of movement was becoming more limited.
He thought he was just getting older, but when he was hiking an uphill trail in Lake Tahoe, he kept tripping over rocks. "I'd never had this happen before," Robert says. "I knew something was wrong but didn't know what it was."
It wasn't until age 50 when he was diagnosed with Charcot-Marie-Tooth disease. The genetic disorder damages the peripheral nerves, which connect the brain and spinal cord to the rest of the body. This network of nerves is responsible for relaying information and signals about sensation, movement, and motor coordination. Over time, the disease causes debilitating muscle weakness and the loss of limb control.
Charcot-Marie-Tooth usually presents itself in childhood or in a person's teens, but in some patients, like Robert, onset can be later in life. Symptoms may include muscle cramping, tingling, or burning. Many patients also have high foot arches or hammer toes — toes that curl from the middle joint instead of pointing forward. Those affected often have difficulty walking and may lose sensation in their lower legs, feet, hands, or forearms. One of the most common rare diseases, it affects around 130,000 people in the United States and 2.8 million worldwide.
Like many people with Charcot-Marie-Tooth, or CMT, Robert wears corrective braces on his legs to help with walking. Now 61, he can't run or sail anymore because of the disease, but he still works out regularly and can hike occasionally. CMT also affects his grip, so he has to use special straps while doing some exercises.
For the past few years, Robert has been participating in a clinical trial for an investigational CMT drug. He takes the liquid formulation every morning and evening using an oral syringe. Scientists are following patients like Robert to learn if their symptoms stabilize or improve while on the drug. Dubbed PXT300, the drug was designed by French biopharmaceutical company Pharnext and is the farthest along in development for CMT. If approved, it would be the first drug for the disease.
Currently, there's no cure for CMT, only supportive treatments like pain medication. Some individuals receive physical and occupational therapy. A drug for CMT could be a game-changer for patients whose quality of life is severely affected by the disease.
Genetic Underpinnings
CMT arises from mutations in genes that are responsible for creating and maintaining the myelin sheath — the insulating layer around nerves. Pharnext's drug is meant to treat patients with CMT1A, the most common form of the disease, which represents about half of CMT cases. Around 5% of those with CMT1A become severely disabled and end up in wheelchairs. People with CMT1A have an extra copy of the gene PMP22, which makes a protein that's needed to maintain the myelin sheath around peripheral nerves.
Typically, an individual inherits one copy of PMP22 from each parent. But a person with CMT1A receives a copy of PMP22 from one parent and two copies from a parent with the disease. This extra copy of the gene results in excess protein production, which damages the cells responsible for preserving and regenerating the myelin sheath, called Schwann cells.
The myelin sheath helps ensure that a signal from the brain gets carried to nerves in the muscles so that a part of the body can carry out a particular action or movement. This sheath is like the insulation on an electrical cord and the action is like a light bulb. If the insulation is fine, the light bulb turns on. But if the insulation is frayed, the light will flicker.
"The same happens to these patients," says David Horn Solomon, CEO of Pharnext. "The signal to their muscle is weak and flickers." Over time, their muscles become weaker and thinner.
The PMP22 gene has proven difficult to target with a drug because it's located in a protected space — the Schwann cells that make up the insulation around nerves. "There's not an easy way to tamp it down," Solomon says.
Another company, Acceleron Pharma of Cambridge, Massachusetts, was developing an injectable CMT drug meant to increase the strength of leg muscles. But the company halted development last year after the experimental drug failed in a mid-stage trial. While the drug led to a statistically significant increase in muscle volume, it didn't translate to improvements in muscle function or quality of life for trial participants.
Made by Design
Pharnext's drug, PXT3003, is a combination of three existing drugs — baclofen, a muscle relaxant; naltrexone, a drug that decreases the desire for alcohol and opioids; and sorbitol, a type of sugar alcohol.
The company designed the drug using its artificial intelligence platform, which screened 20,000 existing drugs to predict combinations that could inhibit the PMP22 gene and thereby lower protein production. The AI system narrowed the search to several hundreds of combinations and Pharnext tested around 75 of them in the lab before landing on baclofen, naltrexone, and sorbitol. Individually, the drugs don't have much effect on the PMP22 gene. But combined, they work to lower how much protein the gene makes.
"How the drug inside the cell reduces expression isn't quite clear yet," says Florian Thomas, director of the Hereditary Neuropathy Center, and founding chair and professor in the department of neurology at Hackensack University Medical Center and Hackensack Meridian School of Medicine in New Jersey (no relation to Robert Thomas, the CMT patient). "By reducing the amount of protein being produced, we hopefully can stabilize the nerves."
In rodents genetically engineered to have the PMP22 gene, the drug reduced protein levels and delayed onset of muscle weakness when given to rats. In another animal study, the drug increased the size of the myelin sheath around nerves in rats.
"Like humans with CMT, one of the problems the animals have is they can't grip things, their grip strength is poor," Solomon says. But when treated with Pharnext's drug, "the grip strength of these animals improves dramatically even over 12 weeks."
Human trials look encouraging, too. But the company ran into a manufacturing issue during a late-stage trial. The drug requires refrigeration, and as a result of temperature changes, crystals formed inside vials containing the high dose of the drug. The study was a double-blind trial, meaning neither the trial participants nor investigators were supposed to know who received the high dose of the drug, who received the low dose, and who received a placebo. In these types of studies, the placebo and experimental drug should look the same so that investigators can't tell them apart. But because only the high dose contained crystals, not the low dose or placebo, regulators said the trial data could be biased.
Pharnext is now conducting a new randomized, double-blind trial to prove that its drug works. The study is recruiting individuals aged 16 through 65 years old with mild to moderate CMT. The company hopes to show that the drug can stop patients' symptoms from worsening, or in the best case scenario, possibly even improve them. The company doesn't think the drug will be able to help people with severe forms of the disease.
"In neurologic disease, you're looking for plasticity, where there's still the possibility of stabilization or reversal," Solomon says. Plasticity refers to the ability of the nervous system to change and adapt in response to stimuli.
Preventing Disability
Allison Moore, a CMT patient and founder and CEO of the Hereditary Neuropathy Foundation, has been following drug development for CMT since she founded the organization in 2001. She says many investigational drugs haven't moved forward because they've shown little success in animals. The fact that Pharnext's drug has made it to a late-stage human trial is promising, she says.
"It's really exciting," Moore says. "There's a chance that if you take the drug early before you're very severe, you'll end up not developing the disease to a level that's super disabling."
CMT has damaged Moore's peroneal nerve, a main nerve in the foot. As a result, she has foot drop, the inability to lift the front part of her foot, and needs to wear leg braces to help her walk. "The idea that you could take this early on and that it could stop progression, that's the hope that we have."
Thomas, the neurologist, says a drug doesn't have to be a cure to have a significant impact on patients. "If I have a CMT patient who's 50 years old, that patient will be more disabled by age 60," he says. "If I can treat that person with a drug, and that person is just as disabled at age 60 as they were at age 50, that's transformative in my mind."
While Robert Thomas says he hasn't noticed a dramatic improvement since he's been on the drug, he does think it's helping. Robert is now in an open-label study, which means he and his health provider are aware that he's receiving the drug.
When the COVID-19 pandemic hit, manufacturing and supply chain disruptions meant that Robert was without the trial drug for two months. When his medication ran out, his legs felt unstable again and walking was harder. "There was a clear distinction between being on and off that medication," he says.
Pharnext's current trial will take about a year and a half to complete. After that, the FDA will decide on whether to approve the drug for CMT patients.
As scientists learn more about the PMP22 gene and the more than 100 other genes that when mutated cause CMT, more precise treatments could be possible. For instance, scientists have used the gene-editing tool CRISPR to correct a CMT-causing mutation in human cells in the lab. The results were published August 16 in the journal Frontiers in Cell and Developmental Biology.
Pharnext is also interested in pursuing genetic treatments for CMT, but in the meantime, repurposed drugs may be the best shot at helping patients until more advanced treatments are available.