Posted on NIH. 2 March, 2021
The National Institutes of Health (NIH) is our nation’s medical research agency. Its mission focuses on scientific discoveries that improve health and save lives. Founded in 1870, the NIH conducts its own scientific research through its Intramural Research Program (IRP), which supports approximately 1,200 principal investigators and more than 4,000 postdoctoral fellows conducting basic, translational and clinical research. In this blog, we will highlight recent innovative NIH research.
Ten years ago, a young woman from Chicago came to the National Institutes of Health with a rare genetic condition. A mutation in her DNA was making her metabolic system malfunction, causing levels of fat molecules called triglycerides in her blood to skyrocket far out of the normal range. This triggered inflammation in her pancreas, a painful and potentially life-threatening condition known as pancreatitis. She couldn’t understand why there wasn’t any kind of treatment to help her.
IRP senior investigator Dr. Alan Remaley took on the challenge with the help of Dr. Anna Wolska, a research fellow in his lab at the National Heart, Lung and Blood Institute (NHLBI). Their research efforts led to the discovery of a novel method for the effective treatment for pancreatitis and heart disease through the reduction of triglycerides in the bloodstream.
A number of studies have shown a correlation between a high level of triglycerides in the blood and an increased risk of heart disease and acute pancreatitis. Triglycerides in the bloodstream are broken down into fatty acids by an enzyme called lipoprotein lipase (LPL), which is regulated by specific proteins. One of these proteins, called apolipoprotein C-II (apoC-II), activates LPL, triggering it to break down triglycerides. At the same time, a second protein called apolipoprotein C-III (apoC-III) blocks the action of the LPL enzyme. In a normally functioning system, these two proteins work in conjunction to maintain a healthy balance of triglycerides in the bloodstream.
Factors including diet, alcohol consumption, certain medications, as well as genetic predisposition can disrupt this balance resulting in an increase in triglyceride levels. In the case of Dr. Remaley’s patient, a rare genetic mutation damaged the apoC-II protein, causing a significant imbalance in the system. The resulting high production of triglycerides accumulating in her bloodstream at dangerous levels led to the development of pancreatitis.
“Usually if you’re a healthy person, you should have below 150 milligrams per deciliter of triglycerides in your blood,” explains Dr. Wolska. However, among people with a serious genetic defect, she says, “we may see over 10,000 milligrams per deciliter of triglycerides — their blood is basically cream.”
The root cause of the patient’s issue was the absence of the production of the apoC-II protein due to the genetic mutation. The research team sought to address the problem by creating a synthetic peptide to replace it. With the help of IRP computer simulation experts Dr. Richard Pastor and postdoctoral fellow Dr. Mohsen Pourmousa, the team was able to simulate the interaction of apoC-II with fat molecules using a supercomputer located at the Pittsburgh Supercomputing Center. “That gave us a clue as to what piece of apoC-II we would need to synthesize so that our peptide would work,” says Dr. Remaley.
Using the computer simulation models, the IRP team was able to identify several candidate peptides having structures that could mimic apoC-II activity. Subsequent testing on mice determined that peptide candidate D6PV was effective in lowering triglyceride levels by approximately 90%. “In an hour, you could see the effect of the peptide clearing all this fat from the blood,” recalls Dr. Wolska.
Additional tests concluded that D6PV worked efficiently on mice that were bred to have very high triglyceride level despite having functioning apoC-II. This observation indicated that D6PV was lowering triglycerides through a second mechanism separate from its effects on apoC-II. The study revealed that the synthetic peptide also blocked apoC-III, the protein responsible for stopping LPL from breaking down triglycerides.
This important research provided the foundation for the development of a drug that can block apoC-III. The NIH entered into a Cooperative Research and Development Agreement (CRADA) with Corvidia Therapeutics, recently acquired by Novo Nordisk, collaborating on turning D6PV into a drug targeting the treatment of individuals with high triglyceride levels. Since striking the agreement, the combined team of scientists have further determined that D6PV exhibits an unusually long half-life that would allow it to remain in the bloodstream for several days. A weekly injection of a drug containing D6PV beneath the skin could dramatically lower blood triglyceride levels, thereby decreasing the risk for heart disease and pancreatitis.
As for the woman from Chicago, Dr. Remaley hopes to bring her back to the NIH for treatment someday so she might benefit from the study she helped instigate. “In fact, we sent the paper to her to let her know that she was the inspiration,” he says.
A leading cause of Alzheimer’s disease is due to the accumulation of toxic proteins in the brain. In the healthy brain, microgila cells engulf and destroy cellular waste and debris. However, in the aging brain, the microglia can fail to perform this vital function of clearing away waste, debris, and protein collections which include amyloid plaques.
In a recent study conducted by researchers from the National Institute of Aging (NIA), patients with Alzheimer’s disease were found to have larger amounts of mitochondrial debris floating in their bloodstream. This discovery provides a biomarker for easily diagnosing or predicting Alzheimer’s in patients. Biomarkers provide a non-invasive method for determining biological signs of the disease and can be easily and inexpensively obtained from a blood sample.
“The brain is inaccessible for direct testing — we cannot take a brain sample,” says Dr. Kapogiannis, NIA clinical investigator and co-senior author of the study. “Ideally, that would be the tissue we would need to examine to understand the disease, but because we cannot do that in living individuals, we have to rely on something that is accessible without invasive procedures, but may still give us relevant information.”
Dr. Kapogiannis’ research has focused on extracellular vesicles (EVs) that are released into the bloodstream and facilitate intercellular communication with other cells to dispose of waste products. In his prior studies, elevated levels of certain protein in EVs ejected from neurons were observed in patients with Alzheimer’s. In the new study, his lab teamed up with researchers led by IRP senior investigator Dr. Myriam Gorospe, the study’s other senior author, to investigate whether strands of RNA might also be present in differing amounts in EVs from Alzheimer’s patients compared to healthy individuals.
The scientists took blood samples from individuals in similar age groups who were either healthy, had Alzheimer’s related dementia or mild cognitive impairment (MCI) due to Alzheimer’s disease. MCI is thought to occur within the early stages of Alzheimer’s. The research team discovered that levels of numerous mitochondrial RNAs were significantly higher in EVs isolated from the blood of patients with Alzheimer’s dementia or MCI compared to those found in the blood of healthy individuals.
“People with MCI who have very mild symptoms and are very early in the course of the disease are already showing very high levels of these mitochondrial RNAs, so it’s a good marker for early detection,” says Dr. Gorospe. “You don’t have to have dementia for this to be a useful biomarker.”
The team further investigated to confirm if the source of the elevated mitochondrial RNA’s were in fact coming from the Alzheimer patients’ brains. Dr. Gorospe’s research team exposed isolated mouse neurons and various types of human brains cells growing in petri dishes to either harmful amyloid-beta proteins known to be involved in Alzheimer’s disease or hydrogen peroxide, a chemical that causes a damaging state known as ‘oxidative stress’ that is thought to afflict brain cells in Alzheimer’s patients. Compared to brain cells exposed to a harmless control solution, the cells exposed to amyloid-beta or hydrogen peroxide released EVs containing more mitochondrial RNA, similar to those found in the blood of Alzheimer’s and MCI patients. Under further examination using a microscope, the scientists were able to visualize materials that closely resembled fragments of mitochondria in EVs released from brain cells exposed to the toxic agents. Additional experiments are required to conclusively confirm these fragments to be the remains of defunct mitochondria.
Larger studies would be required to develop a definitive biomarker test to measure levels of mitochondrial RNA in blood to diagnose or predict Alzheimer’s disease before symptoms become apparent. . “You don’t know how a biomarker operates in a large population until you examine it in a large population.” Explains Dr. Kapogiannis. Developing a blood biomarker based test would enable early intervention in the course of the disease at the stage when interventions are more likely to be effective.
In 1995, nearly twenty-four years before the coronavirus emerged in Wuhan, China, another lethal virus began spreading through parts of Central Africa. The first outbreak of a viral hemorrhagic fever (VHF) like illness occurred in the Democratic Republic of Congo (formerly Zaire) village of Kikwit located near the Ebola River. A second outbreak occurred approximately 500 miles away in what is now South Sudan.
With the fatal epidemic continuing to spread, the Government of Zaire invited a team from the World Health Organization and the CDC to investigate the outbreak. Initial assumptions were that the outbreak was caused by an infected person traveling between the two locations. Upon further study, the team of scientists concluded that the virus, otherwise known as Ebola, came from two different sources and spread independently throughout both areas. Data suggests that the Ebola virus existed long before these outbreaks occurred. Factors such as population growth and encroachment into forested area leading to direct interaction with wildlife have likely led to the spread of the Ebola virus amongst humans.
More than a decade following this initial deadly outbreak, a team of NIH infectious disease scientists would track down one of the survivors and use a sample of the individual’s blood to produce one of the first effective treatments for Ebola. In honor for her contributions to Ebola research which ultimately led to the development of an FDA approved therapy in December, IRP senior investigator Dr. Nancy Sullivan, head of the Biodefense Research Section at the NIH’s Vaccine Research Center (VRC), was named a finalist for the 2020 Samuel J. Heyman Service to America Medals which recognizes outstanding achievements by federal employees such as Dr. Sullivan.
Dr. Sullivan’s graduate research focused on the study of HIV and how a protein located on the virus’s surface binds to a ‘receptor’ protein outside the cell in order to infect it, ultimately turning the cell into a factory for producing more of the virus. “When we think about developing therapies or vaccines for viruses, that binding process is a good one to block,” Dr. Sullivan explains. “It’s the first step for infection, and if you can block that step, you have a pretty good chance of blocking the virus.”
Upon starting her own lab at the NIH, Dr. Sullivan began applying her knowledge of vaccine-induced immune responses to the development of therapeutics. Dr. Sullivan specifically sought to develop a treatment based on monoclonal antibodies, lab-grown copies of the antibody molecules that the immune system naturally produces to nullify a virus. Her prior research on Ebola vaccines was directly applicable to this endeavor since vaccines work by stimulating the immune system to produce antibodies. That work also provided her with critical insights into the traits that an antibody would need to neutralize the Ebola virus.
The protein that Ebola uses to infect cells has a protective ‘cap’ that helps to shield it from the body’s immune system. If the immune system is not able to detect the virus, it is unable to create antibodies against it. Another factor that makes Ebola difficult to combat is that the cellular receptor the virus uses to facilitate infection lies deep within the cell, making it a less accessible target to block with antibodies that are circulating outside the cell. Once inside the cell, the virus uses the cell’s own digestive enzymes to chew off the protective cap, revealing the viral protein that binds to the cell’s receptor and initiating the infection process.
“There will be lots of antibodies that bind to this cap because the cap is on the outside of the virus, but those antibodies are useless once that cap is chewed off,” Dr. Sullivan explains. “So, one of our first questions was whether we could even find an antibody that binds to the virus when the cap is on, stays bound as the virus enters the cell, stays bound as the cell’s enzymes chew off the cap, and then blocks receptor binding.”
In the quest for finding such an antibody, Dr. Sullivan’s team examined antibodies isolated from the blood of a patient who survived the 1995 Ebola outbreak in Kikwit. The researchers theorized that a person who beat the virus might have fought it off with the help of an antibody with the features Dr. Sullivan was seeking — an antibody that the survivor’s immune cells might still be able to produce 20 years later. “This is where the basic science was so important,” she says. “It was studying those molecular interactions between the virus and the immune system for many, many years that allowed us to decide which methods to use to identify the antibody we were looking for.”
The research team was able to identify an antibody, named mAb114, that was highly effective at preventing Ebola from infecting isolated cells in laboratory tests. It was also determined that mAb114 protected macaque monkeys from Ebola infection, even when it was administered as late as five days after the animals were exposed to the virus.
Once mAb114 was shown to be effective in non-human primates, the NIH and Dr. Sullivan’s colleagues at the Institut National de la Recherche Biomédicale (INRB), a medical research organization in the DRC, moved quickly to human trials. The clinical trial compared the effects of mAb114 to three other investigational Ebola therapeutics. It was determined that mAb114 and another monoclonal antibody treatment manufactured by Regeneron Pharmaceuticals both dramatically reduced the death rate of Ebola infected patients. The FDA approved both Regeneron’s monoclonal antibody therapy and mAb114, now under the name Ebanga, in October and December 2020, respectively, making them the first and only effective antiviral therapies for Ebola.
Nearly twenty years of basic research underpins Dr. Sullivan’s work in ultimately finding the right antibody to combat Ebola. That expertise and many of the lessons learned from identifying, containing and treating the Ebola epidemic will continue to inform future research and will be critical in combating a wide array of diseases including those we have yet to encounter. “It probably will become even more important now that we’ve had this awakening with COVID-19,” Dr. Sullivan says. “We need to be able to do this and do it quickly; that is, have that research in place already and be able to move something very quickly to testing in humans. That was the original plan when the VRC was established, and I think licensure of mAb114 by the FDA shows that, in fact, the NIH can do that.”
To protect against COVID-19 transmission, the CDC recommends wearing a mask in public settings, events and gatherings, and while dining in a restaurant, particularly indoors except when actively eating or drinking. Researchers at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDKK) have discovered yet another potential benefit to support the case for wearing a mask. The humidity that is created inside of the mask may also contribute to combating respiratory diseases such as COVID-19.
In this new study, the research team found that face masks substantially increase the amount of humidity in the air that the mask-wearer breathes in. The seasonality associated with respiratory diseases has been correlated to low levels of humidity both indoors and outdoors. Low humidity increases the evaporation of water in the mucosal respiratory tract. Conversely, hydration of the respiratory tract is known to have beneficial effects on immune system and can reduce the spread of a virus to the lungs. The higher levels of humidity in the inhaled air may help explain why the wearing of masks has been linked to a decreased severity of the disease in people infected with the SARS-CoV-2, the virus that causes COVID-19.
“We found that face masks strongly increase the humidity in inhaled air and propose that the resulting hydration of the respiratory tract could be responsible for the documented finding that links lower COVID-19 disease severity to wearing a mask,” said the study’s lead author, Dr. Adriaan Bax, NIH Distinguished Investigator. “High levels of humidity have been shown to mitigate severity of the flu, and it may be applicable to severity of COVID-19 through a similar mechanism.”
High levels of humidity can limit the spread of a virus to the lungs by promoting mucociliary clearance (MCC), a defense mechanism that removes mucus and potentially harmful particles within the mucus from the lungs. High levels of humidity can also bolster the immune system by producing an interferon response to fight against viruses. However, low levels of humidity have been shown to impair both MCC and the interferon response. This may be one of the reasons why cold weather makes it more difficult to fight off respiratory infections.
The study tested four common types of masks: an N95 mask, a three-ply disposable surgical mask, a two-ply cotton-polyester mask, and a heavy cotton mask. The researchers measured the level of humidity by having a volunteer breathe into a sealed steel box. When the person was not wearing a mask, the water vapor of the exhaled breath filled the box, thereby leading to a rapid increase in humidity inside of the box. When the person wore a mask, the buildup of humidity inside the box greatly decreased, due to most of the water vapor condensing in the mask and being re-inhaled. To ensure no leakage, the masks were tightly fitted against the volunteer’s face using high-density foam rubber. Measurements were taken at three different air temperatures, ranging from about 46 to 98 degrees Fahrenheit.
The results showed that all four masks increased the level of humidity of inhaled air, but to varying degrees. At lower temperatures, the humidifying effects of all masks greatly increased. At all temperatures, the thick cotton mask led to the highest increased level of humidity. “The increased level of humidity is something most mask-wearers probably felt without being able to recognize, and without realizing that this humidity might actually be good for them,” said Bax.
The research team did not evaluate the effectiveness of the various masks against the inhalation or transmission of the SARS-CoV-2 virus. Recommendations from the CDC for guidance on choosing a mask can be found here. Prior studies from Dr. Bax and his colleagues showed that any cloth mask can aid in blocking saliva droplets that are released through normal speech and can remain in the air for many minutes. “Even as more people nationwide begin to get vaccinated, we must remain vigilant about doing our part to prevent the spread of the coronavirus that causes COVID-19,” said NIDDK Director Dr. Griffin Rodgers. “This research supports the importance of mask-wearing as a simple, yet effective, way to protect the people around us and to protect ourselves from respiratory infection, especially during these winter months when susceptibility to these viruses increases.”
The emergence of several significant variants of SARS-CoV-2, the virus that causes COVID-19 has rapidly gained worldwide attention amongst health and science experts. In a recent article published in The Journal of the American Medical Association (JAMA), experts from the National Institute of Allergy and Infectious Diseases (NIAID) reported on how new variants became predominant through a process of evolutionary selection. The article also raised concerns about whether vaccines currently authorized for use will protect against new variants, and the need for a global approach to fighting SARS-CoV-2 as the virus spreads and continues to mutate.
In the article, written by NIAID Director Dr. Anthony Fauci, Dr. John Mascola, Director of NIAID’s Vaccine Research Center (VRC); and Dr. Barney Graham, Deputy Director of NIAID’s VRC, the authors noted that the appearance of SARS-CoV-2 variants is so recent that the World Health Organization and other groups are still developing appropriate nomenclature for the numerous different variants that have emerged over the last few months. To communicate effectively about new SARS-CoV-2 variants within the health and scientific community, a common nomenclature is required
Variants known as B.1.1.7 (first identified in the United Kingdom) and B.1.351 (first identified in South Africa) concern scientists because of emerging data suggesting their increased transmissibility. Variants can carry several different mutations, however, changes surrounding the spike protein of the virus that is used to enter cells and infect them are particularly concerning. Changes to the spike protein may cause a vaccine to be less effective against that particular variant. The authors note that the B.1.351 variant may be partially or fully resistant to certain SARS-CoV-2 monoclonal antibodies that are currently authorized for use as therapeutics in the United States.
The identification of all new variants, including a new emergent strain in California called 20C/S:452R, requires a systematic evaluation. The authors state that as SARS-CoV-2 continues to spread, it has the potential to evolve into new variants. Therefore, the fight against SARS-CoV-2 and COVID-19 will require robust surveillance, tracking, and vaccine deployment worldwide. It is further noted that the infrastructure and process that is in place for tracking and updating influenza vaccines could be used to inform that process.
The authors also indicate the need for a pan-coronavirus vaccine. Once researchers gain a better understanding about how the virus evolves as it spreads, it may be possible to develop a vaccine that protects against most or all variants. While similar research programs are already in place for other diseases, such as influenza, the changing nature of SARS-CoV-2 indicates that they will be necessary for this virus.
2021 RNA Biology Symposium
Sponsored by the NCI RNA Biology Initiative
Wednesday, April 14, 2021 to Friday, April 16, 2021 (register by April 9)
National Cancer Institute RNA Biology Symposium
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