Stimulating immune cells with two cancer immunotherapies together can shrink the size of the viral “reservoir” in SIV (simian immunodeficiency virus)-infected nonhuman primates treated with antiviral drugs, Emory researchers and their colleagues have concluded. The reservoir includes immune cells that harbor virus despite potent antiviral drug treatment.
The findings, reported in Nature Medicine, have important implications for the quest to cure HIV because reservoir shrinkage has not been achieved consistently before. However, the combination treatment does not prevent or delay viral rebound once antiviral drugs are stopped. Finding an HIV cure is important because, although antiretroviral therapy can reduce the amount of circulating virus to undetectable levels, problematic issues remain such as social stigma in addition to the long-term toxicity and cost of antiretroviral drugs.
“It’s a glass-half-full situation,” says senior author Mirko Paiardini, PhD. “We concluded immune checkpoint blockade, even a very effective combination, is unlikely to achieve viral remission as a standalone treatment during antiretroviral therapy.”
He adds the approach may have greater potential if combined with other immune-stimulating agents. Or it could be deployed at a different point — when the immune system is engaged in fighting the virus, creating a target-rich environment. Other HIV/AIDS researchers have started to test those tactics, he says.
Paiardini is an associate professor of pathology and laboratory medicine at Emory University School of Medicine and a researcher at Yerkes National Primate Research Center. The study performed in nonhuman primates, considered the best animal model for HIV studies, was carried out in collaboration with co-authors Shari Gordon and David Favre at the University of North Carolina at Chapel Hill and GlaxoSmithKline; Katharine Bar at the University of Pennsylvania; and Jake Estes at Oregon Health & Science University. Read more
A collaboration we wrote about back in 2017, between Emory cell biology chair Gary Bassell and University of Florida neurogeneticist Eric Wang, is taking off.
The National Institute of Neurological Disorders and Stroke has awarded Bassell’s and Wang’s laboratories $2.2 million over five years to examine the neuronal function of Muscleblind-like proteins, which play key roles in myotonic dystrophy.
Gary Bassell and Eric Wang have been collaborating on myotonic dystrophy research
The classic symptom for myotonic dystrophy is having trouble releasing one’s grip on a doorknob, but it is a multi-system disorder, caused by expanded DNA triplet or quadruplet repeats. RNA from the expanded repeats is thought to bind and sequester Muscleblind-like proteins, leading to an impaired process of RNA splicing.
Bassell says the project is expected to clarify how Muscleblind-like proteins regulate RNA localization in neurons and also identify therapeutic targets. In recent years, the DM research community has been paying increasing attention to neurologic symptoms.
Congratulations to the CureGRIN Foundation, which was recently awarded a capacity-building grant from the Chan Zuckerberg Initiative’s Rare as One Network. The Chan Zuckerberg Initiative is giving 30 patient advocacy groups such as CureGRIN $450,000 each over two years.
CureGRIN works closely with Emory pharmacologist Stephen Traynelis, who has been investigating rare genetic disorders affecting NMDA receptors, which play key roles in memory, learning and neuronal development. When NMDA receptor function is perturbed by mutations, symptoms appear in infancy or early childhood, usually including epilepsy and developmental delay.
For the grant, Traynelis is named as the lead researcher for the CureGRIN Foundation, with Tim Benke of Children’s Hospital Colorado as lead clinician. Traynelis is director of the Center for Functional Evaluation of Rare Variants, which hosted a gathering at Emory Conference Center that brought together several GRIN-oriented patient advocacy groups in September 2019.
An influential theory about the anatomical trajectory of Parkinson’s disease is getting a microbial boost. The idea, first proposed by neuroanatomist Heiko Braak in 2003, is that pathology and neurodegeneration start in the intestines and then travel to the brain. See this article in Scientific American for background.
Illustration showing neurons with Lewy bodies, depicted as small red spheres, which are deposits of aggregated proteins in brain cells
Timothy Sampson, in Emory’s Department of Physiology, was first author on a recent paper in eLife, which explores the idea that prion-like proteins produced by intestinal bacteria can accelerate the aggregation of similar proteins found in our cells. The findings suggest that interventions targeting intestinal bacteria could modulate neurodegeneration.
Sampson, a former Emory graduate student who did postdoctoral work in Sarkis Mazmaniam’s lab at Caltech, says he will continue the project here. He and his colleagues were looking at the interaction between a bacterial protein called Curli – involved in adhesion + biofilms — and the aggregation-prone mammalian protein alpha-synuclein, known as a main component of the Lewy body clumps seen in Parkinson’s. The experiments were in a mouse model of Parkinson’s neurodegeneration, in which human alpha-synuclein is overproduced.
Looking ahead, Sampson says he is interested in what signals from the microbiome may trigger, accelerate or slow synuclein aggregation. He’s also looking at where in the GI tract synuclein begins to aggregate, possibly facilitated by particular cells in the intestine, and whether the observations with alpha-synuclein hold true for other proteins such as amyloid-beta in Alzheimer’s.
A huge cancer genome project has highlighted how DNA that doesn’t code for proteins is still important for keeping our cells on track.
The Pan-Cancer Analysis of Whole Genomes analyzed more than 2,600 tumors from 38 tissues, looking for causative mutations and patterns. Previous work had concentrated on the regions of the genome that code for proteins, but a significant proportion of cancer patients’ tumors don’t carry known “driver” (causative) mutations in protein-coding regions. So this project went out into what used to be called “junk DNA” or the “dark matter” of the genome.
Emory bioinformatics postdoc Matthew Reyna is the first author of one of 23 papers on the PCAWG project, published Feb. 5 in the Nature family of journals. His paper in Nature Communications looks at mutations in non-coding regions of the genome in tumors, analyzing which biological processes are affected.
Some of these were mutations in the promoters of genes encoding well-known cancer suppressors such as p53, but the project also identified new genes containing cancer-driving mutations. A promoter is the stretch of DNA that tells the cell “make RNA copies starting here”.
Reyna contributed to the project while he was at Princeton, working with Benjamin Raphael, and at Emory as well. More recently, he’s been investigating protein-protein interactions with Haian Fu, Andrey Ivanov and others as part of the Cancer Target Discovery and Development (CTD2) project.
In a mouse model of chronic viral infection, there are very few virus-specific killer T cells in the blood, Emory Vaccine Center scientists report in a new paper in PNAS. This has implications for efforts to enhance cancer immunotherapy, because in both chronic viral infection and cancer, the same types of exhausted T cells accumulate.
CD8 T cells in lymphoid tissue (spleen) – from Im et al Nature (2016)
Vaccine Center director Rafi Ahmed’s lab has learned a great deal about exhausted T cells by studying the LCMV (lymphocytic choriomeningitis virus) model. In this situation, virus-specific CD8 T cells accumulate in lymph nodes and in other organs, without circulating in the blood, because they acquire a residency program, the PNAS authors write. Postdoc Sejin Im’s 2016 paper defined these “stem-like” cells – he is the first author of the new one as well.
A related phenomenon can be seen in the Kissick lab’s recent paper on immune “outposts” in kidney and other urologic tumors. The stem-like cells stay within the tumor and give rise to similar progeny. One consequence may be that treatments aimed at reactivating those cells need to get inside the tumor.
A recent paper in Journal of Virology mixes tried-and-true cancer-fighting tactics with the exotic. Sort of a peanut-butter-and-chocolate story, but definitely not tasty!
The tried and true is doxorubicin (Adriamycin), the notorious ‘red devil’ chemotherapy drug, which has been around for decades. On the exotic side, we have oncolytic viruses – viruses retuned to attack cancer cells more than healthy cells. This idea finally made it to FDA approval in 2015 in the form of a re-engineered herpes virus directed against melanoma.
Bernardo Mainou’s lab in the Department of Pediatrics is combining both of these approaches together. He and his team are looking to supercharge reoviruses, a mostly harmless type of virus that has been adapted into an anticancer agent. A Canadian company has brought its reovirus forward into several cancer clinical trials, but its product has not gotten to the finish line.
In the JVI paper, graduate students Roxana Rodriguez-Stewart, Jameson Berry and their colleagues infected triple-negative breast cancer cells with a variety of reoviruses, in an effort to select for those that replicate better in those cells. They also looked for drugs that enhance viral infection of those cells, and landed on doxorubicin and related drugs. Doxorubicin is part of a class of anticancer drugs that inhibit topoisomerases, enzymes that unwind DNA as part of the process of replication.
Yesterday at the GDBBS graduate research symposium, Berry gave a talk about the next step: attaching the souped-up reovirus to doxorubicin.
Three varieties of reovirus were grown together in breast cancer cells to select for efficient replication.
Intestinal microbes are necessary for the actions of an important hormone regulating bone density, according to two papers from the Emory Microbiome Research Center. The papers represent a collaboration between Roberto Pacifici, MD and colleagues in the Department of Medicine and laboratory of Rheinallt Jones, PhD in the Department of Pediatrics.
Together, the results show how probiotics or nutritional supplementation could be used to modulate immune cell activity related to bone health. The two papers, published in Nature Communications and Journal of Clinical Investigation, are the first reports of a role for intestinal microbes in the mechanism of action of PTH (parathyroid hormone), Pacifici says.
PTH increases calcium levels in the blood and can either drive bone loss or bone formation, depending on how it is produced or administered. Continuous excessive production of PTH, or primary hyperparathyroidism, is a common endocrine cause of osteoporosis. Yet in another context, intermittent external PTH stimulates bone formation, and is an FDA-approved treatment for osteoporosis – also used off-label for fracture repair in athletes. Read more