Elevated troponin after exercise refines cardiac risk prediction

Elevated troponin levels in response to exercise can predict future outcomes in patients with coronary artery disease -- better than stress tests with Read more

Delayed mechanical strain promotes angiogenesis in bone/wound healing

The natural processes of wound or bone healing rely on the growth of new blood vessels, or angiogenesis. If someone breaks a bone, it is standard practice to apply a cast and immobilize the broken bone, so that healing can proceed without mechanical distortion. 

After those initial stages of healing, applying surprising amounts of pressure can encourage angiogenesis, according to a new paper in Science Advances from biomedical engineer Nick Willett’s lab.

“These data have implications directly on bone healing and more broadly on wound healing,” Willett says. “In bone healing or grafting scenarios, physicians are often quite conservative in how quickly patients begin to load the repair site.”

Willett’s lab is part of both Emory’s Department of Orthopedics and the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory, and is based at the Atlanta Veterans Affairs Medical Center.

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Posted on by Quinn Eastman in Uncategorized Leave a comment

Burning fat like a baby

Newborn humans and hibernating mammals have high levels of brown adipose tissue, which they use to generate heat. Adult humans generally don’t have abundant brown adipose tissue, even if they have lots of “white” fat. Increasing brown fat’s activity may be an approach to treat obesity and related metabolic disorders.

Recently researchers identified an enzyme called Them1 (thioesterase superfamily member 1) as a factor that limits heat generation in brown adipose tissue. Emory biochemist Eric Ortlund and his lab showed how part of the Them1 enzyme binds a certain type of lipid molecule, and also how that part of the enzyme anchors the enzyme close to lipid droplets in adipose cells. Former graduate student Matt Tillman, now a postdoc at Duke, was the first author of the new paper in Proceedings of the National Academy of Sciences.

“In this study, we show Them1 contains a lipid sensor module that detects specific lipids within the cell to regulate its activity,” says Tillman.

In brown adipose cells, the lipid-sensing domain of Them1 is needed for localization around lipid droplets

From Tillman et al PNAS (2020)

He and his colleagues showed that a lipid known for its role in cell signaling, lysophosphatidylcholine or LPC, inhibits Them1 activity, which in turn activates thermogenesis in brown adipose tissue. In contrast, other fatty acids that serve as fuel tend to activate Them1. This regulatory system within Them1 allows the cell to sense its metabolic state and decide when to burn or conserve fat.

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Preparing for weapons production

At Lab Land, we have been thinking and writing a lot about plasma cells, which are like mobile microscopic weapons factories.

Plasma cells secrete antibodies. They are immune cells that appear in the blood (temporarily) and the bone marrow (long-term). A primary objective for a vaccine – whether it’s against SARS-CoV-2, flu or something else — is to stimulate the creation of plasma cells.

A new paper from Jerry Boss’s lab in Nature Communications goes into fine detail on how plasma cells develop. Boss is one of the world authorities on this process. Assistant professor Christopher Scharer and graduate student Dillon Patterson are co-first authors of the paper.

“We are excited about this paper because it shows specific paths and choices that these immune cells make. These previously unknown paths unfold very early in the differentiation scheme as B cells convert their biochemical machinery to become antibody factories,” Boss says. Read more

At Lab Land, we have been thinking and writing a lot about plasma cells, which are like mobile microscopic weapons factories.

Plasma cells secrete antibodies. They are immune cells that appear in the blood (temporarily) and the bone marrow (long-term). A primary objective for a vaccine – whether it’s against SARS-CoV-2, flu or something else — is to stimulate the creation of plasma cells.

A new paper from Jerry Boss’s lab in Nature Communications goes into fine detail on how plasma cells develop. Boss is one of the world authorities on this process. Assistant professor Christopher Scharer and graduate student Dillon Patterson are co-first authors of the paper.

“We are excited about this paper because it shows specific paths and choices that these immune cells make. These previously unknown paths unfold very early in the differentiation scheme as B cells convert their biochemical machinery to become antibody factories,” Boss says. Read more

Posted on by Quinn Eastman in Immunology 1 Comment

SARS-CoV-2 culture system using human airway cells

Journalist Roxanne Khamsi had an item in Wired highlighting how virologists studying SARS-CoV-2 and its relatives have relied on Vero cells, monkey kidney cells with deficient antiviral responses.

Vero cells are easy to culture and infect with viruses, so they are a standard laboratory workhorse. Unfortunately, they may have given people the wrong idea about the controversial drug hydroxychloroquine, Khamsi writes.

In contrast, Emory virologist Mehul Suthar’s team recently published a Journal of Virology paper on culturing SARS-CoV-2 in primary human airway epithelial cells, which are closer to the cells that the coronavirus actually infects “out on the street.”

Effect of interferon-beta on SARS-CoV-2 in primary human epithelial airway cells. Green = SARS-CoV-2, Red = F-actin, Blue = Hoechst (DNA). Courtesy of Abigail Vanderheiden

The Emory researchers found that airway cells are permissive to SARS-CoV-2 infection, but mount a weak antiviral response lacking certain interferons (type I and type III). Interferons are cytokines, part of the immune system’s response to viral infection. They were originally named for their ability to interfere with viral replication, but they also rouse immune cells and bolster cellular defenses.

In SARS-CoV-2 infection, the “misdirected” innate immune response is dominated instead by inflammatory and fibrosis-promoting cytokines, something others have observed as well.

“Early administration of type I or III IFN could potentially decrease virus replication and disease,” the authors conclude. We note that an NIH-supported clinical trial testing a type I interferon (along with remdesivir) for COVID-19 just started.

The first author of the paper is IMP graduate student Abigail Vanderheiden. As with a lot of recent SARS-CoV-2 work, this project included contributions from several labs at Emory: Arash Grakoui’s, Steve Bosinger’s, Larry Anderson’s, and Anice Lowen’s, along with help from University of Texas Medical Branch at Galveston.

Posted on by Quinn Eastman in Immunology Leave a comment

Triple play in science communication

Emory BCDB graduate student Emma D’Agostino

We are highlighting Emory BCDB graduate student Emma D’Agostino, who is a rare triple play in the realm of science communication.

Emma has her own blog, where she talks about what it’s like to have cystic fibrosis. Recent posts have discussed the science of the disease and how she makes complicated treatment decisions together with her doctors. She’s an advisor to the Cystic Fibrosis Foundation on patient safety, communicating research and including the CF community in the research process. She’s also working in biochemist Eric Ortlund’s lab on nuclear receptors in the liver:drug targets for the treatment of diabetes and intestinal diseases.

The triple play is this — on her blog, Emma has discussed how she has to deal with antibiotic resistance. Emory Antibiotic Resistance Center director David Weiss’ lab has published a lot on colistin: how it’s a last-resort drug because of side effects, and how difficult-to-detect resistance to it is spreading. Emma has some personal experience with colistin that for me, brought the issue closer. Read more

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Deep brain stimulation for narcolepsy: proof of concept in mouse model

Emory neurosurgeon Jon Willie and colleagues recently published a paper on deep brain stimulation in a mouse model of narcolepsy with cataplexy. Nobody has ever tried treating narcolepsy in humans with deep brain stimulation (DBS), and the approach is still at the “proof of concept” stage, Willie says.

People with the “classic” type 1 form of narcolepsy have persistent daytime sleepiness and disrupted nighttime sleep, along with cataplexy (a loss of muscle tone in response to emotions), sleep paralysis and vivid dream-hallucinations that bleed into waking time. If untreated, narcolepsy can profoundly interfere with someone’s life. However, the symptoms can often be effectively, if incompletely, managed with medications. That’s why one question has to be: would DBS, implemented through brain surgery, be appropriate?

The room where it happens. Sandwiched between the thalamus and the pituitary, the hypothalamus is home to several distinct bundles of neurons that regulate appetite, heart rate, blood pressure and sweating, as well as sleep and wake. It’s as if in your house or apartment, the thermostat, alarm clock and fuse box were next to each other.

Emory audiences may be familiar with DBS as a treatment for conditions such as depression or Parkinson’s disease, because of the pioneering roles played by investigators such as Helen Mayberg and Mahlon DeLong. Depression and Parkinson’s can also often be treated with medication – but the effectiveness can wane, and DBS is reserved for the most severe cases. For difficult cases of narcolepsy, investigators have been willing to consider brain tissue transplants or immunotherapies in an effort to mitigate or interrupt neurological damage, and similar cost-benefit-risk analyses would have to take place for DBS.

Willie’s paper is also remarkable because it reflects how much is now known about how narcolepsy develops. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

In current vaccine research, adjuvants are no secret

Visionary immunologist Charlie Janeway was known for calling adjuvants – vaccine additives that enhance the immune response – a “dirty little secret.”

Charlie Janeway, MD, in a hat he wore often

Janeway’s point was that foreign antigens, by themselves, were unable to stimulate the components of the adaptive immune system (T and B cells) without signals from the innate immune system. Adjuvants facilitate that help.

By now, adjuvants are hardly a secret, looking at some of the research that has been coming out of Emory Vaccine Center. This week, an analysis by Ali Ellebedy, now at Washington University St Louis, and colleagues showed that in healthy volunteers, the AS03 adjuvant boosted otherwise poor immune responses to a limited dose of the exotic avian flu H5N1, recruiting both memory and naïve B cells. More on that here.

The Moderna SARS-CoV-2 vaccine, which has shown some activity in a small clinical trial here at Emory, has its own kind of adjuvant, since it’s made of both innate-immune-stimulating mRNA and clothed in lipid nanoparticles. Extra adjuvants may come into play later, either with this vaccine or others.

A question we’ve seen many people asking, and discussed on Twitter etc is this: how long does the immunity induced by a SARS-CoV-2 vaccine last? How can we make the immune cells induced by a vaccine stick around for a long time? Read more

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Study finds ‘important implications’ to understanding immunity against COVID-19

New research from Emory University indicates that nearly all people hospitalized with COVID-19 develop virus-neutralizing antibodies within six days of testing positive. The findings will be key in helping researchers understand protective immunity against SARS-CoV-2 and in informing vaccine development.

The test that Emory researchers developed also could help determine whether convalescent plasma from COVID-19 survivors can provide immunity to others, and which donors’ plasma should be used.

The antibody test developed by Emory and validated with samples from diagnosed patients has demonstrated that not all antibody tests are created equal – and that neutralizing antibodies, which provide immunity, have specific characteristics. Emory’s study focused on those neutralizing antibodies, which can stop the virus from infecting other cells.

The findings are now available on MedRxiv, the preprint server for health sciences, and are not yet peer-reviewed.

In the study, researchers looked at antibodies against the receptor-binding domain (RBD), part of the spike protein on the outside of the virus. The RBD is what grips on to human cells and allows the virus to enter them. The researchers focused on antibodies against the RBD because the sequence of the RBD in SARS-CoV-2 distinguishes it from other coronaviruses that cause the common cold.

The receptor-binding domain, or RBD, is what grips on to human cells and allows the virus to enter them.

The initial 44 patient blood samples used in this study were from patients being treated for COVID-19 at Emory University Hospital and Emory University Hospital Midtown.

“These findings have important implications for our understanding of protective immunity against SARS-CoV-2, the use of immune plasma as a therapy, and the development of much-needed vaccines,” says Mehul S. Suthar, PhD, co-lead author and assistant professor of pediatrics at Emory University School of Medicine and Emory Vaccine Center. This study serves as the initial step in a much larger serology effort.

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Emory plays leading role in landmark HIV prevention study of injectable long-acting cabotegravir

Emory University played a key role in a landmark international study evaluating the safety and efficacy of the long-acting, injectable drug, cabotegravir (CAB LA), for HIV prevention.

The randomized, controlled, double-blind study found that cabotegravir was 69% more effective (95% CI 41%-84%) in preventing HIV acquisition in men who have sex with men (MSM) and transgender women who have sex with men when compared to the current standard of care, daily oral emtricitabine/tenofovir disoproxil fumarate 200 mg and 300 mg (FTC/TDF) tablets.

The study achieved its primary objective of non-inferiority with the difference approaching superiority in favor of cabotegravir, pending final analysis.

The findings were so positive that, during a planned review of study data, an independent Data and Safety Monitoring Board (DSMB) recommended the study results be announced as soon as possible. The study sponsor, the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, agreed with that recommendation.

Emory, through the Emory-CDC HIV Clinical Trials Unit, enrolled 7% of the study’s more than 4,500 worldwide participants at three of its clinical research sites: The Hope Clinic (86 participants) and the Ponce de Leon Center (35 participants) in Atlanta and at the CDC’s Silom Community Clinic in Bangkok, Thailand (203 participants).

“This is a landmark study with a new approach that will change how HIV prevention is being done and will open the field to future interventions,” says Carlos del Rio, MD, the executive associate dean, Emory University School of Medicine at Grady Health System. Del Rio is a member of the study team and the principal investigator at the Ponce de Leon Center.

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Yerkes researchers find Zika infection soon after birth leads to long-term brain problems

Researchers from the Yerkes National Primate Research Center have shown Zika virus infection soon after birth leads to long-term brain and behavior problems, including persistent socioemotional, cognitive and motor deficits, as well as abnormalities in brain structure and function. This study is one of the first to shed light on potential long-term effects of Zika infection after birth.

“Researchers have shown the devastating damage Zika virus causes to a fetus, but we had questions about what happens to the developing brain of a young child who gets infected by Zika,” says lead researcher Ann Chahroudi, MD, PhD, an affiliate scientist in the Division of Microbiology and Immunology at Yerkes, director of the Center for Childhood Infections and Vaccines (CCIV), Children’s Healthcare of Atlanta (CHOA) and Emory University, and an associate professor of pediatrics in the Division of Pediatric Infectious Diseases at Emory University School of Medicine.

“Our pilot study in nonhuman primates provides clues that Zika virus infection during the early postnatal period can have long-lasting impact on how the brain develops and works, and how this scenario has the potential to impact child behavior,” Chahroudi continues.

The study, published online in Nature Communicationsfollowed four infant rhesus monkeys for one year after Zika virus infection at one month of age. Studying a rhesus monkey until the age of 1 translates to the equivalent of 4 to 5 years in human age. Researchers found postnatal Zika virus infections led to Impairments in memory function, significant changes in behavior, including reduced social interactions and increased emotional reactions, and some gross motor deficits. These changes corresponded with structural and functional brain changes the researchers found on MRI scans – findings that indicate long-term neurologic complications.

“Our findings demonstrate neurodevelopmental changes detected at 3 and 6 months of age are persistent,” says first author Jessica Raper, PhD, research assistant professor at Yerkes. (See Science Translational Medicine for an earlier study by members of the current research team.) “This is significant because it gives healthcare providers a better understanding of possible complications of Zika beyond infection during pregnancy and into the first years of life,” she adds.
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