Now, in a new study, researchers at the University of Wisconsin School of Veterinary Medicine describe another way the bacterium can cause harm: by undermining the body’s ability to heal from those infections.

The findings may point the way toward improving treatment of infections with S. aureus, more commonly called a staph infection.

Wilmara Salgado-Pabón

The S. aureus bacteria produce small toxins, called superantigens, that bind to white blood cells and over-activate the immune system, which can cause complications for the circulatory system. The study in rabbits, published recently in Science Advances, found that a superantigen called SEC (superantigen staphylococcal enterotoxin C) prevents injured blood vessels from healing. It also stops the formation of new branching blood vessels crucial to the wound repair process.

“The role of many immune system molecules is to make the vessels around the infection more permeable, so they can enter and heal the infection,” explains senior author Wilmara Salgado-Pabón, professor of pathobiological sciences. “But when superantigens hyperactivate the immune system, your blood vessels can become leaky, leading to low blood pressure and organ dysfunction.”

When an area of the body has suffered injury, it will form tiny branching blood vessels called capillaries, which send nutrients and oxygen to the damaged area. Using what’s called the aortic root model, researchers sliced small sections of a rabbit’s aortic artery to imitate an injury. These ring slices were unable to form new capillaries in the presence of SEC, hindering the vascular system from healing the injury.

The model works well, says Salgado-Pabón, “because it allows us to test capillary formation — which can be complex — in a laboratory environment, with all of the elements you would expect in the body.”

Infective endocarditis disproportionately affects Black and Indigenous populations, as well as people predisposed to infection — such as the elderly, people with diabetes and people who smoke.

The condition is responsible for high rates of in-hospital mortality, as it progresses very quickly and can go on to cause complications in other organs throughout the body, Salgado-Pabón says.

Over the last 50 years, treatment for infective endocarditis has remained largely unchanged, currently consisting of a six-week course of antibiotics or heart surgery to clear the infection. The new findings offer potential for developing new and better approaches.

“You could not only neutralize the toxins’ vascular effects, but you could possibly treat patients to improve their vascular health,” says Salgado-Pabón, whose work is supported by the National Institutes of Health. “By strengthening a patient’s vascular health, you could proactively prevent the complications that lead to fatality.”

Now that the lab has identified this new biological function, it is working to define the structures and molecules that are critical to the process, including identifying the molecules SEC interacts with and defining the cellular receptors that react to the toxin’s presence.

This work was supported by NIH grants R01AI34692-01 (to W.S.-P.), R01AI136500 (to J.E.G.), 5T32AI007511-23 (to P.M.T.), and T32GM008365 (to K.J.K.).

The study, published recently in the Journal of Neuroscience, may lead to earlier diagnosis of epilepsy and possibly new ways to treat epilepsy and other disorders that share symptoms, like Alzheimer’s disease, traumatic brain injury and autism spectrum disorder.

Temporal lobe epilepsy, marked by seizures in the brain’s centers for learning and memory, affects more than half of the 3.4 million people in the U.S. diagnosed with epilepsy. One part of the temporal lobe, called the dentate gyrus, has long been suspected to work as a gate — helping to manage brain activity by getting choosy about which patterns of brain cells are active and which are silenced.

Antoine Madar

Matt Jones

“You can think of each pattern as representing one memory,” says Antoine Madar, now a postdoctoral researcher at the University of Chicago, who conducted the research while earning his doctorate at UW­–Madison in the lab of neuroscience Professor Matt Jones. “One pattern represents the first time you visited an art museum. Another, similar pattern is going to represent the second time you went to the museum.”

The unique features of each memory may be subtle — from the specific art you admired, different friends along for the experience or even the time of day — but they are important for guiding specific recollections. Researchers like Madar suspected the dentate gyrus helps to discriminate between similar memories, withholding all but the appropriate patterns to prevent confusion.

“In epilepsy, there is this huge rewiring of the dentate gyrus. Some cells die, some new neurons and new connections between neurons are added in the wrong places” Madar says. “It’s a dramatic difference from a healthy dentate gyrus.”

This rewiring, along with molecular changes inside each cell, allows seizures to develop. But it’s unclear what effect this reorganization of the dentate gyrus has on memory.

With the help of UW–Madison neurologists Bruce Hermann and Rama Maganti, the researchers studied patients in the UW Health’s Epilepsy Monitoring Unit, asking them to take image recognition tests. These tests revealed the trouble they had discriminating between similar memories relative to healthy people of similar age and gender.

The study may lead to earlier diagnosis of epilepsy and possibly new ways to treat epilepsy, Alzheimer’s disease, traumatic brain injury and autism spectrum disorder.

The researchers also studied a mouse model of epilepsy and tested their memory by releasing them repeatedly into an arena with a pair of identical objects. Each time a mouse returned to the arena, one of the objects had been moved to a different location.

“Normal mice noticed and acted like something was different. They spent extra time exploring the object that was in a new location,” says Jones, whose work is supported by the National Institutes of Health. “Mice with epilepsy explored, but they did not show a preference for any object; they behaved as if nothing had changed, confusing the new situation with their memory of the old one.”

Looking for the cause of that confusion, Madar examined brain tissue taken from the mice that had undergone memory testing. With a series of specific electrical pulses, he stimulated the nerve fibers that serve as inputs to the dentate gyrus and recorded the patterns of neuronal activity at the output of the dentate gate.

In healthy mice, similar input patterns were transformed by the dentate gyrus network into easily distinguishable patterns of output activity. The input patterns simulated different but similar memories. In epileptic mice, that process was broken. A subset of the neurons was not doing its job to separate patterns. Instead of transmitting a single impulse from Madar’s electrodes, the epileptic neurons would pass along bursts of pulses.

“We wonder if the same deficits in dentate gyrus function that cause memory problems are simultaneously causing susceptibility to these seizures,” Jones says. “That abnormal activity leads to over-excitation, and that’s how seizures happen.”

The new study, which received support from the Madison-based Lily’s Fund for Epilepsy Research, improves our understanding of the mechanisms of memory, linking the biological function of the dentate gyrus and the ability to avoid memory confusion. This could lead to better care for patients with epilepsy and similar disorders that feature memory impairments or seizures, especially if the new findings help researchers differentiate between brain cells that are damaged and those that retain normal function.

“Identifying markers to specifically target pathological neurons could allow treatment of both seizures and memory symptoms with fewer side effects than current anti-seizure drugs,” Madar says.

Because memory problems often precede the seizure that leads to an epilepsy diagnosis, they could be used to diagnose patients earlier.

“Take a person who’s had a head injury: They could evaluate their own memory regularly, using inexpensive and noninvasive computer-based tests like we used,” Jones says. “If they start showing progressive deficits, a clinician could propose treatment to make sure they never have a first seizure.”

Morgridge Institute for Research investigator Phillip Newmark

A research team led by Morgridge investigator Phillip Newmark reported in the Oct. 17, 2019 issue of PLOS Biology the successful characterization of this chemical, which could lead to new ways to fight the neglected tropical disease schistosomiasis. This disease, caused by schistosome infection, affects more than 240 million people in Africa, Asia and parts of South America.

In fact, schistosomiasis is second only to malaria in sheer numbers of people infected, and children are most often the victims. The disease is common in tropical areas where freshwater and human wastewater are not separated, allowing the schistosome to thrive.

The Newmark team focused on a phase of the schistosome life cycle that’s an intriguing target for preventing infection. Schistosomes seek out freshwater snails as hosts in order to produce millions of tiny fork-tailed creatures called cercariae, which are unleashed in the water and seek out mammals to infect. Their frenzied swimming allows them to penetrate human skin in minutes.

However, tiny aquatic creatures called rotifers also live on these snails and release a chemical compound that paralyzes cercariae on contact. Scientists have known about this factor for decades but have not further probed its biochemistry.

University of Wisconsin–Madison graduate student Jiarong Gao

In the new paper, the Newmark lab and collaborators in Jonathan Sweedler’s laboratory at the University of Illinois at Urbana-Champaign report their successful effort to purify and chemically define this molecule, calling it “schistosome paralysis factor” (SPF). Lead author and University of Wisconsin–Madison graduate student Jiarong Gao placed SPF in various concentrations in water and demonstrated that the compound immobilized the cercariae, which promptly sank to the bottom of the water and remained in that state. Further, she showed that cercariae exposed to SPF were unable to infect mice.

Newmark, a professor of integrative biology at UW–Madison and an investigator of the Howard Hughes Medical Institute, says the results could open a promising new path to controlling schistosomiasis. Currently only a single drug, praziquantel, is used to treat infection and is given to millions of school children each year. But it only kills adult schistosomes and does not stop reinfection.

“Any time you’re talking about treating that many people with just one drug and no alternative, you’re really concerned about the ability of the parasites to develop resistance,” Newmark says.  “And that’s becoming more and more of an issue as the geographic range of the parasite may be spreading and hybrids between human- and livestock-infecting schistosome species are being reported.”

The Phil Newmark Lab has isolated a natural chemical capable of paralyzing the parasitic worm schistosome, opening the door to new ways to combat a neglected tropical disease that sickens more than 240 million people. Video: Morgridge Institute for Research

Once schistosomes burrow inside host skin, the parasites migrate into the blood vessels and anchor on a vein that supplies the liver. During this process, the parasites reorganize their tissues, and upon reaching the liver, develop reproductive organs, pair with a mate, and grow into mature adults.

At this point, the adults can live for decades inside the host. They produce hundreds to thousands of eggs daily, many of which are not expelled through waste and become lodged in organs such as the liver. Children with the disease are often ravaged by anemia, malnutrition and pervasive learning disabilities. The World Health Organization estimates roughly 280,000 people die annually from schistosomiasis.

Schistosomiasis is second only to malaria in sheer numbers of people infected, affecting more than 240 million people in Africa, Asia and parts of South America. Children are most often the victims.

Newmark says one interesting element of SPF is that its structure resembles serotonin, a neurotransmitter most widely known for regulating mood. But it also has an impact on normal neuromuscular function and SPF may be interfering with that pathway.

This research would not have been possible without a key discovery in 1981 by Peg Stirewalt and Fred Lewis of the Biomedical Research Institute in Rockville, Maryland. They found that the rotifers — which are known for the flowing filaments on their heads that look like spinning wheels — produced a factor that paralyzed cercariae.

But until now, their sole impact on schistosome research was to keep them away from snails because they interfered with the infection process. Newmark turned the equation around and put the rotifers in the spotlight.

The Newmark lab first ventured into studying schistosomes about 10 years ago. The lab’s primary focus has been on the planarian, an organism that can regenerate its entire body from tiny fragments. The researchers recognized the many similarities between planarians and schistosomes, and then applied more than two decades of advances in planarian cell and molecular biology to study its parasitic relatives.

“All the work that we’ve done has been driven by our curiosity about these amazing planarians and all the different things that they can do,” Newmark says. “But we now have a new end game: We could actually wind up helping people in a tangible way, on a scale that we could not have considered before.”

What got you into the stem cell business in the first place?

My work was always research, but I was trying to find a way to deal with patient problems; I came from medical school. With brain cells, the source of material is critical. You could study canine or rodent neural stem cells, but they are not human. For neural cells, you have to take them from the brain, which means from abortions or from surgical tissue. I was looking to overcome these ethical and practical issues, and I started working with Jamie [Thomson] even before his human ES cell discovery.

“The pure science is fascinating, but when I talk to patients, I see their anxiety, their desire to move ahead,” says Su-Chun Zhang. “But as a scientist, or as a doctor, the number one thing is to make sure you do not create harm, and so we move cautiously.” UW Health / John Maniaci

After I got the ES cells and watched them differentiate, I quickly saw the neural cells. The neural stem cells line up beautifully in a neural tube-like rosette. The neural tube is the structure from which our brain and spinal cord form. I grabbed Jamie to have a look, and he told me he’d seen those cells many times. I came from the neural field, so I immediately knew what I was seeing. But Jamie was an expert in stem cells, so he did not pay attention. It was remarkable, very fascinating to me, rewarding. In science this happens all the time. Science requires people from different fields to generate something new.

It’s been 20 years now and stem cells have not yet provided any treatments for human neurological problems. Why is it so hard to derive such treatments?

When we started, we thought these cells could be extremely useful for patients, but the problem is extremely difficult. We spent many years arguing about the morality and legality of using embryonic stem cells. That’s over, but the brain is a very special organ where the cells are wired very precisely, and that complicates the work greatly. The first step is getting a pure population of cells of the exact type of neuron.

Parkinson’s, for example, results from the death of neurons deep in the brain that make a neurotransmitter called dopamine. So to treat Parkinson’s, you need the midbrain type of dopamine-creating neuron, not just any kind of dopamine neuron. Although we can’t yet produce pure populations of those cells, we’re getting close.

These astrocytes were derived from human stem cells. Red shows the structural protein, GFAP, which gives the cell its distinctive starlike shape. DNA in the cell nucleus appears blue. Jeffrey Jones / Zhang lab

The overriding issue is safety. It’s not enough to prove that transplanted cells don’t generate a tumor; we also need to ensure they don’t create other problems. The brain is almost unfathomably complex, and if transplanted cells wire incorrectly, that can be worse than useless. Animals seem easier compared to humans. We can get cell replacement to treat the animal model of Parkinson’s, but there we only look at motor function. With a human being, we need to consider thinking, reasoning, memory, talking, emotions, to name a few.

Are you frustrated?

Yes, because I always want to move it to the clinic. The pure science is fascinating, but when I talk to patients, I see their anxiety, their desire to move ahead. But as a scientist, or as a doctor, the number one thing is to make sure you do not create harm, and so we move cautiously. Look around: For any new drug development, 15 years is a common time course. Yet here we are dealing with living cells, which are vastly more complex. And once you put them into the brain, you cannot scoop them out if something goes wrong.

What have stem cells taught us about how human brains develop and work?

It turns out that human brain cells behave very differently than animal cells. For example, we published a paper saying that the genes that control brain development are different in humans compared to animals. This may explain why, most of the time, drugs that work in animals do not help patients, particularly for neural problems.

Kaiping Xu dispenses cells at BrainXell, a UW–Madison spinoff founded to pursue Su-Chun Zhang’s processes for developing stem cells into neural cells. Photo: David Tenenbaum

Take the fatal disease ALS, which is caused by a degeneration of motor neurons. There are a dozen effective treatments for animal models, but none of the clinical trials have been effective for patients. This pains me, but it also motivates me.

With the development of iPS cells, you can get stem cells from patients and look at the disease process. Previously, we’ve had to use animal models, transgenic cells or cells with genes knocked out. They’re less realistic, less effective as research tools.

But here’s a clue: iPS cells from ALS patients show a mutant protein in the motor neuron, but it’s not at a sky-high level, unlike what we see in the animal model. In animals, when we have a load of misshapen proteins, the cell’s response is not an authentic replica of what happens in the human body. It’s misleading. That discovery led to the next step, which was to build a drug screening platform to test drugs. Once you think you know the mechanism, it becomes much easier to evaluate thousands of compounds very quickly, and then you are doing it in human cells. When you look at patient cells directly, you see the real thing.

Where do you see the field in another 5–10 years?

There should be something in the clinic. I’d bet on a few conditions with local pathology or a defined cell type, such as Parkinson’s, spinal cord injury, and possibly Huntington’s disease or even stroke. For some disorders, cell therapy could remain quite difficult. Alzheimer’s, for example, is a very diffuse wiring problem.

But I also see that the basic science is setting us up for more victories further down the road. Ask anyone in neuroscience: The need has never been greater.

Three cross-section images of nerve tissue from cats, each showing an individual oligodendrocyte cell (marked with “O”) among nerve cell axons surrounded by dark-colored sheaths of myelin. Mature myelin sheaths (around axons marked with asterisks) are thick. Thin sheaths (marked with arrows) are remyelinated by the pictured oligodendrocyte. Images from Duncan et al, PNAS, 2018

Nerve cells stripped of their insulation can no longer carry vital information, leading to the numbness, weakness and vision problems often associated with multiple sclerosis. A new study shows an overlooked source may be able to replace that lost insulation and provide a new way to treat diseases like MS.

Cells called neurons make the central nervous system work by passing electrical signals along threadlike connections called axons. Axons do their work best when wrapped in an insulating coating of a fatty substance called myelin.

“When you lose myelin, axons don’t conduct at their normal speed or don’t conduct at all,” says Ian Duncan, a neuroscientist at the University of Wisconsin–Madison’s School of Veterinary Medicine. “And if enough of them are affected — such as in a big area of demyelination in MS — you develop clinical symptoms related to that part of the nervous system.”

Ian Duncan

Myelin is made by oligodendrocytes, cells that can reach out to several nearby axons to wrap parts of them in the protective myelin sheath.

Consensus has held that once an axon is robbed of its myelin, the only way to bring it back is by starting with fresh oligodendrocytes. Only oligodendrocytes arising from precursors called oligodendrocyte progenitor cells can apply a new coat of myelin to axons, goes the dogma. Thus, MS treatments aimed at remyelination have focused on recruiting progenitor cells in demyelinated areas (called plaques), and spurring them to develop.

However, researchers led by Duncan have shown in a study published today in the Proceedings of the National Academy of Sciences that starting from progenitor cells is not the only route to remyelination. In cats and rhesus macaques experiencing a severe loss of myelin, Duncan found fully developed oligodendrocytes already in place were reaching out and beginning to coat affected axons with myelin once again.

The catch, if there is one, is that to be helpful and remyelinate damaged axons, the adult oligodendrocytes may still need to have connections to surviving myelin segments — called “internodes” — on other axons.

“If this cell is still biologically active and maintaining these internodes, it can re-extend processes out to these demyelinated segments,” says Duncan, whose work is supported by the National Multiple Sclerosis Society. “Those processes can make new myelin sheaths, which end up being thinner and shorter than the previous internodes.”

But even thinner myelin will restore nerve function, as Duncan and colleagues reported in 2009.

Cats fed irradiated food for several months develop severe myelin loss throughout the nervous system. When the cats returned to a regular diet, nerve function was restored because of extensive myelin repair.

Nerve cell extensions called axons (green) are sheathed in protective myelin (red) provided by nearby cells called oligodendrocytes (blue). New research shows oligodendrocytes can respond to damage to myelin sections by creating a thin replacement coating of myelin. Graphic modified from Duncan et al, PNAS, 2018

The cats’ demyelination problems are unusual as a lab model of the disease.

“The de facto model to study demyelination and remyelination is in a mouse fed a toxin called cuprizone,” Duncan says. “But the toxin kills oligodendrocytes. So, studying the mouse, you naturally wouldn’t see any of the original oligodendrocytes beginning remyelination.”

In the new study, the researchers looked at the cats’ nervous tissue and found a unique myelin mosaic — axons surrounded by thick layers of myelin (formed during development when the axons themselves grew) were interspersed with other axons surrounded by thin layers of myelin.

“The most likely explanation of that mosaic appearance is surviving oligos,” Duncan says. “Thick myelin sheaths are never seen following remyelination, just thin sheaths. And surviving adult oligodendrocytes are adjacent to these sites of demyelination, making them likely candidates for myelin repair.”

Sure enough, the researchers found oligodendrocytes connected to both thick and thin myelin sheaths in the cat spinal cord.

The discovery of the mature myelin-producing cells’ capacity for repair opens new opportunities to slow or reverse the disease.

They also found this association when they reached back to a decades-old monkey model of demyelination. Neuropathologist Dimitri Agamanolis tried to make a model of another human demyelinating disease — called sub-acute combined degeneration and caused by Vitamin B12 deficiency — at Case Western Reserve University in the 1970s. Agamanolis had saved preserved blocks of sampled nervous tissue from the monkeys, and he shared them with Duncan. The monkeys’ myelin lesions resembled those in the cats.

“You see in the monkeys, too, single oligodendrocytes connected to mature myelin sheaths that also have processes extended out to and surrounding demyelinated axons,” Duncan says.

The UW–Madison researchers enlisted Grahame Kidd and the private research lab Renovo Neural in Cleveland to reconstruct stacks of electron microscope images of cat nerve cells into 3D representations that show oligodendrocytes reaching up and down the spinal cord, sustaining mature myelin and remyelinating damaged sheaths.

The process may not be playing out in human MS patients fast enough to help mitigate the progression of the disease, Duncan says. Or too many oligodendrocytes may lose so many of their internodal connections that they become inactive or die.

But the discovery of the mature myelin-producing cells’ capacity for repair opens new opportunities to slow or reverse the disease.

“Right now, the emphasis is on promoting the numbers of oligo progenitors and their differentiation, particularly into adult oligodendrocytes,” says Duncan. “What this work provides is a different target.”

That target will call for new therapeutic approaches — finding drugs, for example, that rally the oligodendrocytes to reach out with new lifelines to damaged myelin sheaths.

“In fighting complex diseases, such as MS, the more tools you have on hand, the better,” Duncan says. “If these adult cells are recruitable in some fashion, we should be looking at ways to do it.”

Duncan’s co-authors on the study include Kidd and UW–Madison neuroscience researchers Abigail Radcliff and Moones Heidari, veterinary medicine student Lauren Wierenga, and electron microscopy specialist Benjamin August.

Globally, TB is caused by seven major strains.

Caitlin Pepperell Submitted photo

“Yes, I was surprised at the lack of diversity in the bacterium,” said Caitlin Pepperell, an associate professor of medical microbiology at University of Wisconsin-Madison. Pepperell is a corresponding author in a paper published online today (Nov. 5) in Nature Ecology and Evolution that looked at 4,578 samples from patients in China.

Pepperell’s co-authors included Qian Gao and Qingyun Liu, both at the Shanghai Public Health Clinical Center and Fudan University in Shanghai.

China has about one million new cases of TB annually, a number that is slowly falling. Each year, 10 million cases of TB account for an estimated 1.7 million deaths globally, making it the most deadly infectious disease. The pandemic is particularly acute in developing countries in Asia and sub-Saharan Africa.

The most likely explanation for the uniformity of TB strains in China is political. Movement into the old empire was limited by dynastic policies of seclusion, Pepperell says. “The hypothesis my colleagues and I use to explain the surprising lack of diversity is that at the time when the current TB epidemic was taking hold in China, there was less contact with other regions compared to contemporaneous societies elsewhere, but there was a lot of movement within China.”

That internal movement allowed the strain Lineage 2 or L2 to spread widely in China, where it now accounts for 80 percent of current cases. L2 is estimated to have arisen in Southeast Asia, with subsequent evolution of important daughter strains within China.

The introduction of strain Lineage 4, which now causes 17 percent of cases in China, was likely from ships engaged in the silk trade between 1084 and 1336 A.D.

Map shows movement of two subtypes of the tuberculosis bacterium lineage 4 after `it was introduced, presumably by infected sailors. Today, lineage 4 causes 17 percent of China’s tuberculosis cases. Pepperell, et al., Nature Ecology & Evolution

And because apparently few other strains were introduced into China, the result is a picture not seen elsewhere – of two dominant strains in a pandemic that has persisted for a thousand years or more.

Several features distinguish TB from other pathogens and make its evolution dependent on human behavior. Mycobacterium tuberculosis does not share DNA with other species of bacteria. This dangerous phenomenon, called “horizontal gene transfer,” allows rapid movement of traits like antibiotic resistance among bacteria.

And because TB has no non-human hosts, it infects only through human-to-human contact, producing a slower advance compared to many other epidemics.

Although these factors could help explain why a political decision to isolate China allowed two strains to move through the country largely unchanged, the study was not designed to prove causation.

The new study adds to an emerging picture of the movement of the dangerous and persistent TB epidemic across the globe. In a recent report in Science Advances, Pepperell and colleagues studied Lineage 4, the predominant international strain, and concluded that “repeated sourcing from Europe has been the main driving force for the global expansion of L4, with intense dispersal to Africa and the Americas concomitant with European colonizing efforts” between the years 1600 and 1900.

That study also found that strains of TB resistant to multiple drugs in recent decades have “overwhelmingly” remained local. That encouraging finding raises the possibility of limiting the spread of these particularly dangerous pathogens.

After decades of little progress in drug treatment for TB, new drugs are already in use or in the pipeline, Pepperell adds. However, because many people stop taking the pills before the bacterium is fully vanquished, standard practice calls for practitioners to watch that doses are actually taken for at least the six months needed to clear the infection.

Pepperell, who practices infectious disease medicine in addition to her research, says a main goal of the genetic studies is to gain an evolutionary understanding of why TB is so difficult to treat and eradicate. “We talk about robustness and adaptability,” she says. “A robust organism is strong in the face of perturbations. Adaptability is the ability to change in response to a change in environmental conditions.”

Clearly, the Lineage 2 strain that dominates in China is robust. It is also a major cause of drug resistant TB, demonstrating its adaptability as well.   

The current study alone, she adds, “will not tell us why treatment and eradication of TB is so difficult, and it will not change treatment, directly. The overarching contribution of this kind of study is to understand what forces shaped these bacteria. That is obviously relevant to treatment, and to drug resistance, but you can’t draw a direct line from what we have found so far, saying, ‘These will be the effects.’”

This work was supported by the National Institutes of Health (grant 1R01AI113287-01A1); the Natural Science Foundation of China and other sources.

By the time Parkinson’s disease patients are diagnosed — typically based on the tremors and motor-control symptoms most associated with the disease — about 60 percent of them also have serious damage to the heart’s connections to the sympathetic nervous system. When healthy, those nerves spur the heart to accelerate its pumping to match quick changes in activity and blood pressure.

“This neural degeneration in the heart means patients’ bodies are less prepared to respond to stress and to simple changes like standing up,” says Marina Emborg, a University of Wisconsin–Madison professor of medical physics and Parkinson’s researcher at the Wisconsin National Primate Research Center. “They have increased risk for fatigue, fainting and falling that can cause injury and complicate other symptoms of the disease.”

Marina Emborg

Emborg, graduate student Jeanette Metzger, and colleagues including UW–Madison specialists in cardiology and medical imaging developed a method for tracking the mechanisms that cause the damage to heart nerve cells. They tested the method in the human-like nervous system and heart of monkeys, and published their results today (July 13, 2018) in the journal npj Parkinson’s Disease.

Ten rhesus macaque monkeys served as models for Parkinson’s symptoms, receiving doses of a neurotoxin that caused damage to the nerves in their hearts in much the same way Parkinson’s affects human patients. Once before and twice in the weeks after, the monkeys underwent PET scans — positron emission tomography, a medical imaging technology that can track chemical processes in the body using radioactive tracers.

The UW–Madison researchers used three different tracers, called radioligands, to map three different things in the left ventricle (the strongest pumping chamber) of monkeys’ hearts: where the nerves extending into the heart muscle were damaged, where the heart tissue was experiencing the most inflammation, and where they found the most oxidative stress.

The scans were accurate enough to allow the researchers to focus on changes over time in specific areas of the heart’s left ventricle.

“We know there is damage in the heart in Parkinson’s, but we haven’t been able to look at exactly what’s causing it,” says Metzger, lead author of the study. “Now we can visualize in detail where inflammation and oxidative stress are happening in the heart, and how that relates to how Parkinson’s patients lose those neuronal connections in the heart.”

Heart attacks, diabetes and other disorders cause similar damage to nerves in the heart, and those patients and potential therapies could also benefit from the new visualization method.

By tracing the progression of nerve damage and the progression of potential causes of that damage, the radioligands can also be used to test the efficacy of new treatments to protect the neurons that regulate the activity of the patients’ hearts.

The researchers gave half the monkeys in the study a drug, pioglitazone, that has shown promise in protecting central nervous system cells from inflammation and oxidative stress.

“The recovery of nerve function is much greater in the pioglitazone-treated animals,” says Emborg, whose work is supported by the National Institutes of Health. “And what’s interesting is this method allows us to identify very specifically the differences the treatment made — separately for inflammation and for oxidative stress — across the heart.”

The results suggest human patients could benefit from the radioligand scans, and Metzger wonders if it could help catch some Parkinson’s patients before their other symptoms progress.

“Much of the neural degeneration that occurs in the heart can happen very early in the course of the disease. A lot of patients have problems with their heart before they have motor problems,” she says. “While these PET techniques potentially provide a way to test drugs, they may also be used as tools to understand the mechanisms underlying early heart nerve damage”

The heart problems opened to examination by the new imaging methods are not limited to Parkinson’s disease. Heart attacks, diabetes and other disorders cause similar damage to nerves in the heart, and those patients and potential therapies could also benefit from the new visualization method.

Emborg and Metzger’s UW–Madison collaborators included psychology Professor Emerita Colleen Moore, cardiovascular medicine Professor Timothy Kamp, neurology Professor Catherine Gallagher, and medical physics Professor Bradley Christian and emeritus professors Jerry Nickels and James Holden.

Support for this research was provided by grants from the National Institutes of Health (P51OD011106, R21NS084158, F31HL136047), the Parkinson’s Foundation, Welton and Trewartha undergraduate honors scholarships and UW–Madison.

With the help of experts at Waisman Biomanufacturing, within the University of Wisconsin–Madison’s Waisman Center, UW–Madison School of Veterinary Medicine Professor Yoshihiro Kawaoka will lead a $3 million effort to produce as many as 1,000 doses of an experimental vaccine that has already been proven to work safely in monkeys.

“The goal is to produce a safe and effective vaccine against Ebola virus for people,” says Kawaoka, a world expert on Ebola and influenza. The vaccine is planned for use in a phase 1 clinical trial in Japan and is the only whole-virus Ebola vaccine candidate under development.

It will be produced at Waisman Biomanufacturing, a specialized facility whose mission is to help translate scientific discovery into early-stage clinical trials. The staff of the facility provides expert help with manufacturing processes, quality control and overall product development in addition to regulatory support.

“Waisman Biomanufacturing produces many different types of biopharmaceutical products, keeping our range of expertise broad in order to serve any University of Wisconsin investigator who has a biological that they wish to bring into the clinic,” says Carl Ross, the facility’s managing director. “We have made many prophylactic and therapeutic vaccines for use in human clinical trials.”

The technology behind the new Ebola vaccine was devised nearly a decade ago by Peter Halfmann, a research scientist in Kawaoka’s lab who is also an expert on the Ebola virus. It is known as “Delta VP30,” and is a form of Ebola virus that is noninfectious and safe to work with under routine laboratory conditions such as those at Waisman Biomanufacturing. The virus is missing a critical gene — one of only eight genes that make up the virus genome — that makes a protein the virus needs to reproduce in host cells.

Vaccines work by exposing the immune system to viruses or parts of viruses. The Delta VP30-based vaccine may offer better protection against Ebola virus than others in the pipeline, Kawaoka says, because it is a whole-virus vaccine. Other Ebola vaccine candidates use vector viruses to ferry a single Ebola protein, a surface antigen, to prime the immune system.

“Here, we have a whole-virus vaccine that presents all the viral proteins to the immune system, which may result in increased and broadened immune responses compared to vaccines that present only a single viral antigen to the immune system,” Kawaoka explains.

The need for an Ebola vaccine is acute. Periodic outbreaks of the disease in sub-Saharan Africa, including an epidemic between 2013 and 2016, caused major loss of life and serious economic disruption in the three countries where it occurred: Sierra Leone, Guinea and Liberia.

The technology devised in 2008 by Halfmann in Kawaoka’s lab provides a safe way to explore countermeasures for Ebola, a disease whose high mortality rate is amplified by a lack of clinically-tested vaccines and antiviral compounds. The Delta VP30 technology has been approved by the National Institutes of Health for use under Biosafety Level 2 conditions and has been utilized safely for a decade to study the basic biology of the virus, identify potential antiviral compound candidates, and make the whole-virus vaccine.

The need for an Ebola vaccine is acute. Periodic outbreaks of the disease in sub-Saharan Africa caused major loss of life and serious economic disruption.

“We have 10 years of experience with this system,” says Kawaoka of work performed in the UW–Madison School of Veterinary Medicine and the Influenza Research Institute (IRI) located in University Research Park. “That includes data that demonstrates that the vaccine does not replicate in and is not pathogenic in animals, including mice with deficient immune systems and nonhuman primates.”

Waisman Biomanufacturing, notes Ross, has a long history of producing experimental vaccines for clinical trials, including for HIV, influenza, hepatitis, herpes and human papillomavirus, among others. In addition to its emphasis on producing vaccines, the lab specializes in gene and cell therapies, including stem cell products.

The Ebola vaccine work at Waisman Biomanufacturing will begin in March, with the clinical vaccine doses for the Japanese trial produced by December of 2018.

The new vaccine project will be the subject of an informational meeting to be held Feb. 27 at 4:30 p.m. at the Friends of the Waisman Center Auditorium on the first floor of the West Annex. The Waisman Center is located at 1500 Highland Ave. Free parking is available after 4:30 p.m. in Lot 82, behind the Waisman Center and accessible from Highland Avenue.

With the help of experts at Waisman Biomanufacturing, within the University of Wisconsin–Madison’s Waisman Center, UW–Madison School of Veterinary Medicine Professor Yoshihiro Kawaoka will lead a $3 million effort to produce as many as 1,000 doses of an experimental vaccine that has already been proven to work safely in monkeys.

Ebola virus swarms the surface of a host cell in this electron micrograph. Like most viruses, Ebola requires the help of a host cell to survive and replicate. Photo: Takeshi Noda, University of Tokyo

“The goal is to produce a safe and effective vaccine against Ebola virus for people,” says Kawaoka, a world expert on Ebola and influenza. The vaccine is planned for use in a phase 1 clinical trial in Japan and is the only whole-virus Ebola vaccine candidate under development.

It will be produced at Waisman Biomanufacturing, a specialized facility whose mission is to help translate scientific discovery into early-stage clinical trials. The staff of the facility provides expert help with manufacturing processes, quality control and overall product development in addition to regulatory support.

“Waisman Biomanufacturing produces many different types of biopharmaceutical products, keeping our range of expertise broad in order to serve any University of Wisconsin investigator who has a biological that they wish to bring into the clinic,” says Carl Ross, the facility’s managing director. “We have made many prophylactic and therapeutic vaccines for use in human clinical trials.”

The technology behind the new Ebola vaccine was devised nearly a decade ago by Peter Halfmann, a research scientist in Kawaoka’s lab who is also an expert on the Ebola virus. It is known as “Delta VP30,” and is a form of Ebola virus that is noninfectious and safe to work with under routine laboratory conditions such as those at Waisman Biomanufacturing. The virus is missing a critical gene — one of only eight genes that make up the virus genome — that makes a protein the virus needs to reproduce in host cells.

Yoshihiro Kawaoka

Carl Ross

Vaccines work by exposing the immune system to viruses or parts of viruses. The Delta VP30-based vaccine may offer better protection against Ebola virus than others in the pipeline, Kawaoka says, because it is a whole-virus vaccine. Other Ebola vaccine candidates use vector viruses to ferry a single Ebola protein, a surface antigen, to prime the immune system.

“Here, we have a whole-virus vaccine that presents all the viral proteins to the immune system, which may result in increased and broadened immune responses compared to vaccines that present only a single viral antigen to the immune system,” Kawaoka explains.

The need for an Ebola vaccine is acute. Periodic outbreaks of the disease in sub-Saharan Africa, including an epidemic between 2013 and 2016, caused major loss of life and serious economic disruption in the three countries where it occurred: Sierra Leone, Guinea and Liberia.

The technology devised in 2008 by Halfmann in Kawaoka’s lab provides a safe way to explore countermeasures for Ebola, a disease whose high mortality rate is amplified by a lack of clinically-tested vaccines and antiviral compounds. The Delta VP30 technology has been approved by the National Institutes of Health for use under Biosafety Level 2 conditions and has been utilized safely for a decade to study the basic biology of the virus, identify potential antiviral compound candidates, and make the whole-virus vaccine.

The need for an Ebola vaccine is acute. Periodic outbreaks of the disease in sub-Saharan Africa caused major loss of life and serious economic disruption.

“We have 10 years of experience with this system,” says Kawaoka of work performed in the UW–Madison School of Veterinary Medicine and the Influenza Research Institute (IRI) located in University Research Park. “That includes data that demonstrates that the vaccine does not replicate in and is not pathogenic in animals, including mice with deficient immune systems and nonhuman primates.”

Waisman Biomanufacturing, notes Ross, has a long history of producing experimental vaccines for clinical trials, including for HIV, influenza, hepatitis, herpes and human papillomavirus, among others. In addition to its emphasis on producing vaccines, the lab specializes in gene and cell therapies, including stem cell products.

The Ebola vaccine work at Waisman Biomanufacturing will begin in March, with the clinical vaccine doses for the Japanese trial produced by December of 2018.

The new vaccine project will be the subject of an informational meeting to be held Feb. 27 at 4:30 p.m. at the Friends of the Waisman Center Auditorium on the first floor of the West Annex. The Waisman Center is located at 1500 Highland Ave. Free parking is available after 4:30 p.m. in Lot 82, behind the Waisman Center and accessible from Highland Avenue.

That’s why scientists, investigating an outbreak of respiratory disease in a community of wild chimpanzees in Uganda’s Kibale National Park, were surprised and dismayed to discover that a human “common cold” virus known as rhinovirus C was killing healthy chimps.

“This was an explosive outbreak of severe coughing and sneezing,” says Tony Goldberg, a professor in the University of Wisconsin–Madison’s School of Veterinary Medicine and one of the senior authors of a report documenting the event. The report was published online today (Dec. 13, 2017) in the journal Emerging Infectious Diseases.

“It was completely unknown that rhinovirus C could infect anything other than humans,” says Goldberg, referencing a two-year-old chimp named Betty, who succumbed to the virus and whose body was quickly recovered and autopsied after her death. “It was surprising to find it in chimpanzees, and it was equally surprising that it could kill healthy chimpanzees outright.”

This 2-year-old chimp named Betty succumbed to a human common cold virus in Uganda. The opportunity to retrieve Betty’s body before it decomposed or scavengers set in was critical to making the discovery. Photo: Richard Wrangham

The outbreak occurred in February of 2013 and affected most of the chimps in the community. During that time, five chimps out of a community of 56 died, including Betty; the other animals that died were adults up to 57 years old. The findings, says Goldberg, are a cautionary tale about human interactions with wild apes. In Africa, people encounter chimpanzees and other apes when human settlements expand into ape habitats, through activities like tourism and research, and when apes leave the forests to raid crops.

Rhinovirus C is one of three rhinovirus species, each causing respiratory disease in humans. But rhinovirus C is notably more severe than its relatives, rhinoviruses A and B. Although the virus had likely been infecting people for several thousand years, it was unknown to science until 2006, when it was discovered using new DNA sequencing technologies.

In people, rhinovirus C infection can be especially severe in children, notes James Gern, another senior author of the study and a professor of allergy and immunology in the UW School of Medicine and Public Health. Gern’s lab was the first to grow rhinovirus C in the laboratory where it could be studied. Gern’s lab also described the receptor that the virus uses to infect cells of the respiratory system.

UW–Madison epidemiologist Tony Goldberg investigating primate disease in Africa. He was dismayed to discover that a human common cold virus was killing healthy chimps. Photo: Ronan Donovan

“In general, this virus seems to affect young children the most,” says Gern, whose lab performs high-throughput viral diagnostics, processing thousands of human samples annually. Gern explains that the genetics of the receptor — which serves like a lock-and-key mechanism that allows the virus to enter and infect a host cell — influences who is likely to be most affected by the virus. Some people have a version of the receptor that makes them highly susceptible to the virus while others have a different version that makes them resistant. For some people (young children, in particular) rhinovirus C infection can be a precursor or complicating factor for asthma.

“Chimps seem to be genetically predisposed to have problems with this virus,” Gern says. “The virus found in Betty was one that looked like it came from a human, and the level of virus in the lung was comparable to what we see in children.”

The authors were also able to examine the DNA of the chimps in Uganda using fecal samples, and they looked at published chimp genomes from across Africa. Goldberg says it was sobering to see that every chimp had the receptor that makes cells exquisitely sensitive to rhinovirus C.  “There’s a species-wide susceptibility of chimps to this virus,” says Goldberg.

Ann Palmenberg, a UW-Madison professor of biochemistry and an authority on cold viruses, says the genome of the virus obtained from Betty shows that the virus came from a human host. “We expected to see changes all over the genome, but it is not a chimp-adapted virus.”

Palmenberg, also a senior author of the study, says the virulence of the virus, with about a 9 percent mortality rate, was remarkable. “That’s why kids with the CDHR3 high-risk mutation are at increased risk for being hospitalized with severe respiratory illness.”

The findings, says Goldberg, are a cautionary tale about human interactions with wild apes.

Goldberg, who has worked in Uganda for years tracking viruses in animals, says outbreaks of respiratory disease in wild chimpanzees are not uncommon, but for the most part they go undiagnosed. In the few cases where causes have been identified, other viruses unrelated to rhinovirus C have been in play.

“In most cases, we don’t find out what it is. We’re thinking that rhinovirus C might be a major, missed cause of disease outbreaks in chimps in the wild,” Goldberg notes.

Unlike other viruses known to cause respiratory disease in chimps, though, rhinovirus C is not typically found in feces and may have been overlooked in the past.

Finding rhinovirus C as the cause of the 2013 outbreak in Uganda was part good luck, says Goldberg. The opportunity to retrieve Betty’s body before it decomposed or scavengers set in was critical. So, too, were Goldberg’s colleagues at Harvard and the University of New Mexico, who run a long-term chimp study in Kibale and can identify all the chimps in the community. This, plus the fact that a Ugandan veterinarian was on hand with the proper tools to obtain and secure samples through a post mortem in the field, made the discovery possible, he says.

From On Wisconsin magazine: The Disease Detective