Gene editing reverses Huntington's in mouse model

This is a concrete example, not yet clinical, of what can be done with CRISPR/Cas9 gene Read more

Urine tests for prostate cancer could reduce biopsies

Urine RNA tests could reduce the number of biopsies by giving a preview of a cancer's aggressiveness. Featuring Martin Sanda and Carlos Read more

Mitochondrial blindness -- Newman's Emory story

Neuro-ophthalmologist Nancy Newman’s 2017 Dean’s Distinguished Faculty Lecture and Award were unexpectedly timely. Her talk on Tuesday was a tour of her career and mitochondrial disorders affecting vision, culminating in a description of gene therapy clinical trials for the treatment of Leber’s hereditary optic neuropathy. The sponsor of those studies, Gensight Biologics, recently presented preliminary data on a previous study of their gene therapy at the American Academy of Neurology meeting in April. Two larger trials Read more

Immunology

Case report on first newborn to survive Ebola

Pediatric infectious diseases specialist Anita McElroy was a co-author on a case report on the first newborn to survive Ebola infection, published recently in Journal of Infectious Diseases.

“Of all the work I’ve been privileged to be involved in over the past few years, this paper was one of the most personally satisfying,” McElroy writes.

The child described in the paper is named Nubia; she is mentioned in several news stories from 2015. She was the last known Ebola case in Guinea, one of three African countries hit hard by the virus in 2014 and 2015. Her mother died shortly after her birth.

Nubia leaves hospital in Guinea. Photo from Medecins Sans Frontieres.

Nubia was cared for at the Ebola treatment ward run by Medecins Sans Frontieres (MSF, aka Doctors without Borders) in Conakry, Guinea. She was given three experimental therapies: ZMapp antibodies, survivor white blood cell transfusion and an antiviral drug called GS-5734. It is not clear which of these interventions were critical for Nubia’s recovery, although the paper makes clear that ZMapp did not result in viral suppression all by itself.

McElroy is a go-to person for studies of dangerous viruses such as Ebola, Lassa and Zika, partly because of her affiliation with the Centers for Disease Control and Prevention’s Viral Special Pathogens Branch. She advised the MSF team on the use of the antiviral drug and other interventions.

Posted on by Quinn Eastman in Immunology Leave a comment

Double vision: seeing viruses by both light and electron microscopy

Advances in both light and electron microscopy are improving scientists’ ability to visualize viruses such as HIV, respiratory syncytial virus (RSV), measles, influenza, and Zika in their native states.

Researchers from Emory University School of Medicine and Children’s Healthcare of Atlanta developed workflows for cryo-correlative light and electron microscopy (cryo-CLEM), which were published in the January 2017 issue of Nature Protocols.

An example of the images of viruses obtainable with cryo-CLEM. Pseudotyped HIV-1 particles undergoing endocytosis. Viral membrane = light blue. Mature core = yellow. Clathrin cages = purple. From Hampton et al Nat. Protocols (2016)

Previously, many electron microscopy images of well-known viruses were obtained by studying purified virus preparations. Yet the process of purification can distort the structure of enveloped viruses, says Elizabeth R. Wright, PhD, associate professor of pediatrics at Emory University School of Medicine.

Wright and her colleagues have refined techniques for studying viruses in the context of the cells they infect. That way, they can see in detail how viruses enter and are assembled in cells, or how genetic modifications alter viral structures or processing.

“Much of what is known about how some viruses replicate in cells is really a black box at the ultrastructural level,” she says. “We see ourselves as forming bridges between light and electron microscopy, and opening up new realms of biological questions.”

Wright is director of Emory’s Robert P. Apkarian Integrated Electron Microscopy Core and a Georgia Research Alliance Distinguished Investigator. The co-first authors of the Nature Protocols paper are postdoctoral fellows Cheri Hampton, PhD. and Joshua Strauss, PhD, and graduate students Zunlong Ke and Rebecca Dillard.

The Wright lab’s work on cryo-CLEM includes collaborations with Gregory Melikyan in Emory’s Department of Pediatrics, Phil Santangelo in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory, and Paul Spearman, now at Cincinnati Children’s.

For this technique, virus-infected or transfected cells are grown on fragile carbon-coated gold grids and then “vitrified,” meaning that they are cooled rapidly so that ice crystals do not form. Once cooled, the cells are examined by cryo-fluorescent light microscopy and cryo-electron tomography. Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Four biomedical research topics to watch in 2017

HIV/AIDS

The example of the “Berlin patient,” the only person ever cured of HIV infection, has energized HIV/AIDS researchers around the world. They are exploring a variety of tactics to attack the HIV reservoir in infected people, ranging from gene editing to “kick and kill.” A host of Emory/Yerkes researchers are among those pushing this forward.

This past year, an Emory/NIAID team led by Tab Ansari showed that a gentle, antibody-based approach could suppress SIV infection in macaques for extended periods, which surprised many in the field. The human test of this approach is now underway at the National Institutes of Health.

On the preventive vaccine side, a large scale efficacy study recently begun in South Africa, the first in seven years. Geovax’s Emory-rooted technology continues to advance in clinical studies. Further back in the pipeline, Yerkes researchers are testing innovative approaches, such as Rama Amara’s milk-bacteria-based mucosal vaccine and the potent nanoparticle adjuvants developed by Bali Pulendran’s group.

Zika

Despite the World Health Organization’s declaration in November that the public health emergency is over, Zika infection is still driving brain-related birth defects in several countries. Expect to hear more about Zika epidemiology and vaccine research, including from Emory investigators, next year.

In contrast with HIV, which seems to escape from almost anything we or our immune systems throw at it, Zika is doable, scientists think. At a Vaccine Dinner Club talk in September, Harvard’s Dan Barouch made the case that Zika is a slam dunk, immunologically. Two big questions remain: does dengue get in the way? And can vaccine makers test quickly and distribute widely?

FMT for antibiotic-resistant infections

Emory physicians have been leaders in developing fecal microbiota transplant as a remedy for recurrent Clostridium dificile infection. This form of diarrhea, which can be life-threatening, sometimes arises as a result of antibiotics that wipe out the helpful bacteria that live in the intestines, paving the way for “C diff.”

Now the Emory team (Colleen Kraft/Tanvi Dhere/Aneesh Mehta/Rachel Friedman-Moraco) is testing whether FMT could prevent other antibiotic-resistant infections besides C diff. This approach will be examined in a group of patients that tends to have a lot of antibiotic exposure: kidney transplant recipients. The team’s first publication on this topic from 2014 is here. Read more

Posted on by Quinn Eastman in Immunology, Neuro Leave a comment

Threading the RSV needle: live attenuated vaccine effective in animals

Crafting a vaccine against RSV (respiratory syncytial virus) has been a minefield for 50 years, but scientists believe they have found the right balance.

A 3-D rendering of a live-attenuated respiratory syncytial virus (RSV) particle, captured in a near-to-native state by cryo-electron tomography. Surface glycoproteins (yellow) are anchored on the viral membrane (cyan), with ribonucleoprotein complexes inside (red). Image courtesy of Zunlong Ke and Elizabeth Wright.

Researchers at Emory University School of Medicine and Children’s Healthcare of Atlanta have engineered a version of RSV that is highly attenuated – weakened in its ability to cause disease – yet potent in its ability to induce protective antibodies.

The researchers examined the engineered virus using cryo-electron microscopy and cryo-electron tomography techniques, and showed that it is structurally very similar to wild type virus. When used as a vaccine, it can protect mice and cotton rats from RSV infection.

The results were published this morning in Nature Communications.

“Our paper shows that it’s possible to attenuate RSV without losing any immunogenicity,” says senior author Martin Moore, PhD, associate professor of pediatrics at Emory University School of Medicine and a Children’s Healthcare of Atlanta Research Scholar. “This is a promising live-attenuated vaccine candidate that merits further investigation clinically.”

The next steps for this vaccine are to produce a clinical grade lot and conduct a phase 1 study of safety and immunogenicity in infants, Moore says. Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Insane in the membrane – inflamed in the brain

Inflammation in the brain is a feature of several neurological diseases, ranging from Parkinson’s and Alzheimer’s to epilepsy. Nick Varvel, a postdoc with Ray Dingledine’s lab at Emory, was recently presenting his research and showed some photos illustrating the phenomenon of brain inflammation in status epilepticus (prolonged life-threatening seizures).

The presentation was at a Center for Neurodegenerative Disease seminar; his research was also published in PNAS and at the 2016 Society for Neuroscience meeting.green-red-brain

Varvel was working with mice in which two different types of cells are marked by fluorescent proteins. Both of the cell types come originally from the blood and can be considered immune cells. However, one kind – marked with green — is in the brain all the time, and the red kind enters the brain only when there is an inflammatory breach of the blood brain barrier.

Both markers, CX3CR1 (green) and CCR2 (red), are chemokine receptors. Green fluorescent protein is selectively produced in microglia, which settle in the brain before birth and are thought to have important housekeeping/maintenance functions.

Monocytes, a distinct type of cell that is not usually in the brain in large numbers, are lit up red. Monocytes rush into the brain in status epilepticus, and in traumatic brain injury, hemorrhagic stroke and West Nile virus encephalitis, to name some other conditions where brain inflammation is also seen.

In the PNAS paper, Varvel and his colleagues include a cautionary note about using these mice for studying situations of more prolonged brain inflammation, such as neurodegenerative diseases: the monocytes may turn down production of the red protein over time, so it’s hard to tell if they’re still in the brain after several days.

Targeting CCR2 – good or bad? Depends on the disease model

The researchers make the case that “inhibiting brain invasion of CCR2+ monocytes could represent a viable method for alleviating several deleterious consequences of status epilepticus.” Read more

Posted on by Quinn Eastman in Immunology, Neuro Leave a comment

Antiviral success makes some immune cells stickier

As they succeed in clearing a viral infection from the body, some virus-hunting T cells begin to stick better to their target cells, researchers from Emory Vaccine Center and Georgia Tech have discovered.

The increased affinity helps the T cells kill their target cells more efficiently, but it depends both on the immune cells’ anatomic location and the phase of the infection.

The results were published this week in the journal Immunity.

Arash Grakoui, PhD

Arash Grakoui, PhD

After the peak of the infection, cells within the red pulp of the spleen or in the blood displayed a higher affinity for their targets than those within the white pulp. However, the white pulp T cells were more likely to become long-lasting memory T cells, critical for vaccines.

“These results provide a better understanding of how memory precursor populations are established and may have important implications for the development of efficacious vaccines,” the scientists write.

In the mouse model the researchers were using, the differences in affinity were only detectable a few days after the non-lethal LCMV viral infection peaks. How the differences were detected illustrates the role of serendipity in science, says senior author Arash Grakoui, PhD.

Typically, the scientists would have taken samples only at the peak (day 7 of the infection) and weeks later, when memory T cells had developed, Grakoui says. In January 2014, the weather intervened during one of these experiments. Snow disrupted transportation in the Atlanta area and prevented postdoctoral fellow Young-Jin Seo, PhD from taking samples from the infected mice until day 11, which is when the differences in affinity were apparent.

Seo and Grakoui collaborated with graduate student Prithiviraj Jothikumar and Cheng Zhu, PhD at Georgia Tech, using a technique Zhu’s laboratory has developed to measure the interactions between T cells and their target cells. Co-author Mehul Suthar, PhD performed gene expression analysis.

Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Bad neighbors cause bad blood -> cancer

Certain DNA mutations in bone cells that support blood development can drive leukemia formation in nearby blood stem cells, cancer researchers have found.

Many cancer-driving mutations are “cell-autonomous,” meaning the change in a cell’s DNA makes that same cell grow more rapidly. In contrast, an indirect neighbor cell effect was observed in a mouse model of Noonan syndrome, an inherited disorder that increases the risk of developing leukemia.

bone-marrow-300

In mouse bone marrow, mesenchymal stem cells (red), which normally nurture blood stem cells, produce a signal that is attractive for monocytes. The monocytes (green) prod nearby blood stem cells to proliferate, leading to leukemia. From Dong et al Nature (2016).

The findings were published Wednesday, October 26 in Nature.

The neighbor cell effect could be frustrating efforts to treat leukemias in patients with Noonan syndrome and a related condition, juvenile myelomonocytic leukemia (JMML). That’s because bone marrow transplant may remove the cancerous cells, but not the cause of the problem, leading to disease recurrence. However, the researchers show that a class of drugs can dampen the cancer-driving neighbor effect in mice. One of the drugs, maraviroc, is already FDA-approved against HIV infection.

“Our research highlights the importance of the bone marrow microenvironment,” says Cheng-Kui Qu, MD, PhD, professor of pediatrics at Emory University School of Medicine, Winship Cancer Institute and Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta. “We found that a disease-associated mutation, which disturbs the niches where blood stem cell development occurs, can lead to leukemia formation.”

Editorial note: This Nature News + Views, aptly titled “Bad neighbors cause bad blood,” explains JMML, and how the relapse rate after bone marrow transplant is high (about 50 percent). It also notes that a variety of genetic alterations provoke leukemia when engineered into bone marrow stromal cells in mice (like this), but Qu and his colleagues described one that is associated with a known human disease.

Noonan syndrome often involves short stature, distinctive facial features, congenital heart defects and bleeding problems. It occurs in between one in 1000 to one in 2500 people, and can be caused by mutations in several genes. The most common cause is mutations in the gene PTPN11. Children with Noonan syndrome are estimated to have a risk of developing leukemia or other cancers that is eight times higher than their peers.
Read more

Posted on by Quinn Eastman in Cancer, Immunology Leave a comment

SIV remission follow-up

The surprising finding that an antibody treatment can push SIV-infected monkeys into prolonged remission, even after antiviral drugs are stopped, continues to rumble across the internet.

siv-a4b7-teaser-copy

Blue circles show how viral levels stayed low even after antiretroviral drugs were stopped.

The Science paper was featured on NIH director Francis Collins’ blog this week. NIAID director Anthony Fauci has been giving presentations on the research, which emerged from a collaboration from his lab and Tab Ansari’s at Emory. Fauci’s talk at the recent HIV prevention meeting in Chicago is viewable here.

At Lab Land, we were pleased to see that the watchdogs at Treatment Action Group had this to say:

“Media coverage of the paper has generally been accurate, but has had to wrestle with the uncertainty that exists among scientists regarding how ART-free control of viral load should be described.”

HIV pioneer Robert Gallo noted in an article accompanying the Science paper that the anti-integrin antibody treatment represents an emerging alternative to the vaunted “shock and kill” strategy, which he termed “soothe and snooze.” Note to reporters: the upcoming “Strategies for an HIV cure” conference at NIH in mid-November might be a good chance to compare the different strategies and put them in perspective.

Read more

Posted on by Quinn Eastman in Immunology Leave a comment

Blood versus the crypts

Amielle Moreno

For Halloween, Lab Land welcomes a guest post from Neuroscience graduate student Amielle Moreno, former editor of the Central Sulcus newsletter.

While recent studies have found evidence for the healing properties of blood from younger individuals, the fascination with “young blood” has been a part of the human condition for centuries.

In ancient Greece, Hippocrates introduced the concept that our health and temperament was controlled by the four humors, proposing that blood was the one responsible for courage, playfulness as well as hope. From the 16th century story of Countess Elizabeth Báthory de Ecsed of Hungary, the idea of “blood baths” acquired decidedly more sinister connotations.

The “Blood Countess” holds the Guinness World Record as the most prolific female murderer. With 80 confirmed kills, Báthory might have lured up to 650 peasant girls to her castle with the promise of work as maidservants or courtly training. Instead of etiquette lessons, they were burned, beaten, frozen or starved for the Countess’ sadistic pleasure. Folk stories told how she would bathe in the blood of virgins to preserve her youth and beauty.

Portrait if Elizabeth Bathory, via Wikimedia

Portrait if Elizabeth Bathory, via Wikimedia

Humors remained a staple of traditional western medicine until the 1800s when medical research and our modern concept of medicine emerged. In this more enlightened age, people started sewing animals together to see what would happen.

In the mid-1800s, a French zoologist named Paul Bert first experimented with the creation of parabionts: the surgical joining of two animals, usually two rodents of the same species, in order to study the effect of one’s blood on the other. Read more

Posted on by Quinn Eastman in Heart, Immunology, Neuro Leave a comment

Dengue infection makes exhausted T cells?

An ongoing collaboration between the Emory Vaccine Center and the ICGEB (International Centre for Genetic Engineering and Biotechnology) in New Delh, investigating immune responses to dengue virus, is getting some attention.

A Journal of Virology paper published by the collaboration was highlighted by Nature Asia. In that paper, the researchers show that in dengue infection, the group of antiviral immune cells known as CD8+ T cells undergoes a massive expansion. That could be dangerous if all of the CD8 T cells were making inflammatory cytokines, but they do not. Only a small fraction are making cytokines.

The authors point out that this phenomenon is “somewhat reminiscent of T-cell exhaustion seen under the conditions of prolonged antigenic stimulus in chronic viral infections [which has been studied in detail by Rafi Ahmed and colleagues] or closely resembles the ‘stunned’ phenotype reported in febrile phase of other acute infections such as HIV and viral hepatitis… The IFN-γ unresponsiveness acquired during the massive antigen-driven clonal expansion is likely to ensure that these cells do not cause excessive inflammation at the time that their numbers are high during the febrile phase of dengue disease.” Read more

Posted on by Quinn Eastman in Immunology Leave a comment