Culture

A team of biochemists and virologists at Goethe University and the Frankfurt University Hospital were able to observe how human cells change upon infection with SARS-CoV-2, the virus causing COVID-19 in people. The scientists tested a series of compounds in laboratory models and found some which slowed down or stopped virus reproduction. These results now enable the search for an active substance to be narrowed down to a small number of already approved drugs. (Nature DOI: 10.1038/s41586-020-2332-7). Based on these findings, a US company reports that it is preparing clinical trials. A Canadian company is also starting a clinical study with a different substance.

Since the start of February, the Medical Virology of the Frankfurt University Hospital has been in possession of a SARS-CoV-2 infection cell culture system. The Frankfurt scientists in Professor Sandra Ciesek's team succeeded in cultivating the virus in colon cells from swabs taken from two infected individuals returning from Wuhan (Hoehl et al. NEJM 2020).

Using a technique developed at the Institute for Biochemistry II at Goethe University Frankfurt, researchers from both institutions were together able to show how a SARS-CoV-2 infection changes the human host cells. The scientists used a particular form of mass spectrometry called the mePROD method, which they had developed only a few months previously. This method makes it possible to determine the amount and synthesis rate of thousands of proteins within a cell.

The findings paint a picture of the progression of a SARS-CoV-2 infection: whilst many viruses shut down the host's protein production to the benefit of viral proteins, SARS-CoV-2 only slightly influences the protein production of the host cell, with the viral proteins appearing to be produced in competition to host cell proteins. Instead, a SARS-CoV-2 infection leads to an increased protein synthesis machinery in the cell. The researchers suspected this was a weak spot of the virus and were indeed able to significantly reduce virus reproduction using something known as translation inhibitors, which shut down protein production.

Twenty-four hours after infection, the virus causes distinct changes to the composition of the host proteome: while cholesterol metabolism is reduced, activities in carbohydrate metabolism and in modification of RNA as protein precursors increase. In line with this, the scientists were successful in stopping virus reproduction in cultivated cells by applying inhibitors of these processes. Similar success was achieved by using a substance that inhibits the production of building blocks for the viral genome.

The findings have already created a stir on the other side of the Atlantic: in keeping with common practise since the beginning of the corona crisis, the Frankfurt researchers made these findings immediately available on a preprint server and on the website of the Institute for Biochemistry II. Professor Ivan Dikic, Director of the Institute, comments: "Both the culture of 'open science', in which we share our scientific findings as quickly as possible, and the interdisciplinary collaboration between biochemists and virologists contributed to this success. This project started not even three months ago, and has already revealed new therapeutic approaches to COVID-19."

Professor Sandra Ciesek, Director of the Institute for Medical Virology at the University Hospital Frankfurt, explains: "In a unique situation like this we also have to take new paths in research. An already existing cooperation between the Cinatl and Münch laboratories made it possible to quickly focus the research on SARS-CoV-2. The findings so far are a wonderful affirmation of this approach of cross-disciplinary collaborations."

Among the substances that stopped viral reproduction in the cell culture system was 2-Deoxy-D-Glucose (2-DG), which interferes directly with the carbohydrate metabolism necessary for viral reproduction. The US company Moleculin Biotech possesses a substance called WP1122, a prodrug similar to 2-DG. Recently, Moleculin Biotech announced that they are preparing a clinical trial with this substance based on the results from Frankfurt..

Based on another one of the substances tested in Frankfurt, Ribavirin, the Canadian company Bausch Health Americas is starting a clinical study with 50 participants: https://clinicaltrials.gov/ct2/show/NCT04356677?term=04356677&draw=2&rank=1

Dr Christian Münch, Head of the Protein Quality Control Group at the Institute for Biochemistry II and lead author, comments: "Thanks to the mePROD-technology we developed, we were for the first time able to trace the cellular changes upon infection over time and with high detail in our laboratory. We were obviously aware of the potential scope of our findings. However, they are based on a cell culture system and require further testing. The fact that our findings may now immediately trigger further in vivo studies with the purpose of drug development is definitely a great stroke of luck." Beyond this, there are also other potentially interesting candidates among the inhibitors tested, says Münch, some of which have already been approved for other indications.

Professor Jindrich Cinatl from the Institute of Medical Virology and lead author explains: "The successful use of substances that are components of already approved drugs to combat SARS-CoV-2 is a great opportunity in the fight against the virus. These substances are already well characterised, and we know how they are tolerated by patients. This is why there is currently a global search for these types of substances. In the race against time, our work can now make an important contribution as to which directions promise the fastest success."

A new proof-of-concept study published in the May issue of The Journal of Nuclear Medicine has demonstrated that molecular imaging can be used for identifying early response to 177Lu-DOTATATE treatment in neuroendocrine tumor patients.

Utilizing single photon emission computed tomography (SPECT) imaging with 111In-antiγH2AX-TAT, researchers were able to visualize a DNA damage response marker just days after 177Lu-DOTATATE treatment. Monitoring the DNA damage response in the early days after the radionuclide injection could allow physicians to determine the therapeutic outcome and adapt the therapy regimen accordingly.

The radiobiologic aspects of 177Lu-DOTATATE, as well as other molecular radiotherapies, are underexplored. Radionuclide therapy is largely delivered to neuroendocrine tumor patients on a fixed dose protocol, regardless of body weight or tumor uptake. To justify any increase or decrease in the prescribed radionuclide dose a sustainable metric is needed; however, no metric currently exists.

"One strategy to develop this metric is to determine if sufficient damage has been afflicted to the tumor, which would allow treating physicians to tailor subsequent doses to ensure therapeutic success," said Bart Cornelissen, PhD, associate professor in the department of oncology at the MRC Oxford Institute for Radiation Oncology at the University of Oxford in Oxford, United Kingdom. "In our study, we sought to image the molecular biological effects of 177Lu-DOTATATE radionuclide therapy by visualizing the DNA double-strand break damage response marker γH2AX."

In the study, researchers first exposed six cell lines to external beam therapy or 177Lu-DOTATATE and measured the number of γH2AX foci and the clonogenic survival (which indicate the extent of DNA double-strand break damage). Mice bearing the same cell line were then treated with 177Lu-DOTATATE or sham-treated, and static SPECT images were acquired at one, 24, 48 and 72 hours after administration. Immediately after the first SPECT imaging session, the mice were administered 111In-anti-γH2AX-TAT or 111In-IgG-TAT.

In vitro cell lines exposed to 177Lu-DOTATATE were found to have increased γH2AX foci and decreased clonogenic survival, and reacted very differently than to an equitoxic dose of external beam irradiation. The γH2AX foci induced by 177Lu-DOTATATE in the preclinical models were successfully imaged by SPECT in vivo using 111In-anti-γH2AX-TAT. An accumulation of γH2AX signal was observed over the days after administration of 177Lu-DOTATATE, indicating an increase in DNA damage. Furthermore, γH2AX expression revealed intratumoral and interlesion heterogeneity with the absorbed 177Lu dose, suggesting that different parts of the tumor may react differentially to treatment with 177Lu-DOTATATE.

"The application of this imaging technique could provide a very early indicator of tumor damage without having to wait for changes in tumor volume, which currently may take months to find out," noted Edward O'Neill, postdoctoral researcher in the department of oncology at MRC Oxford Institute for Radiation Oncology at the University of Oxford in Oxford, United Kingdom. "When using therapeutic response assessment with molecular imaging, making rapid decisions becomes possible, including dose reduction to avoid side effects, assessment of combination therapies, or, in the absence of any measurable response, initiation of palliative options designed toward improving quality of life."

Harvard University scientists have identified a new gut-brain connection in the neurodegenerative disease amyotrophic lateral sclerosis, or ALS. The researchers found that in mice with a common ALS genetic mutation, changing the gut microbiome using antibiotics or fecal transplants could prevent or improve disease symptoms.

Published in the journal Nature, the findings provide a potential explanation for why only some individuals carrying the mutation develop ALS. They also point to a possible therapeutic approach based on the microbiome.

"Our study focused on the most commonly mutated gene in patients with ALS. We made the remarkable discovery that the same mouse model -- with identical genetics -- had substantially different health outcomes at our different lab facilities," said Kevin Eggan, Harvard professor of stem cell and regenerative biology. "We traced the different outcomes to distinct gut microbial communities in these mice, and now have an intriguing hypothesis for why some individuals carrying this mutation develop ALS while others do not."

Different facilities, different outcomes

The researchers initially studied the ALS genetic mutation by developing a mouse model at their Harvard lab facility. The mice had an overactive immune response, including inflammation in the nervous system and the rest of the body, which led to a shortened lifespan.

In order to run more detailed experiments, the researchers also developed the mouse model in their lab facility at the Broad Institute, where Eggan is the director of stem cell biology at the Stanley Center for Psychiatric Research. Unexpectedly, although the mice had the same genetic mutation, their health outcomes were dramatically different.

"Many of the inflammatory characteristics that we observed consistently and repeatedly in our Harvard facility mice weren't present in the Broad facility mice. Even more strikingly, the Broad facility mice survived into old age," said Aaron Burberry, postdoctoral fellow in the Eggan lab and lead author of the study. "These observations sparked our endeavor to understand what about the two different environments could be contributing to these different outcomes."

Searching the gut microbiome

Looking for environmental differences between the mice, the researchers honed in on the gut microbiome. By using DNA sequencing to identify gut bacteria, the researchers found specific microbes that were present in the Harvard facility mice but absent in the Broad facility mice, even though the lab conditions were standardized between facilities.

"At this point, we reached out to the broader scientific community, because many different groups have studied the same genetic mouse model and observed different outcomes," Burberry said. "We collected microbiome samples from different labs and sequenced them. At institutions hundreds of miles apart, very similar gut microbes correlated with the extent of disease in these mice."

The researchers then tested ways to change the microbiome and improve outcomes for the Harvard facility mice. By treating the Harvard facility mice with antibiotics or fecal transplants from the Broad facility mice, the researchers successfully decreased inflammation.

Gut-brain connection

By investigating the connection between genetic and environmental factors in ALS, the researchers identified an important gut-brain connection. The gut microbiome could influence the severity of disease -- whether individuals with the genetic mutation develop ALS, the releated condition frontotemporal dementia, or no symptoms at all -- and could be a potential target for therapy.

"Our study provides new insights into the mechanisms underlying ALS, including how the most common ALS genetic mutation contributes to neural inflammation," Eggan said. "The gut-brain axis has been implicated in a range of neurological conditions, including Parkinson's disease and Alzheimer's disease. Our results add weight to the importance of this connection."

Whilst the whole world is in lockdown during the current Corona crisis, certain cells within our bodies are still travelling long-distance: while this happens when you develop pneumonia, any ordinary cut on your finger will also trigger white blood cells--aka leukocytes--to instantly move out of your blood vessels into the site of inflammation. Similarly, cancer cells, which can originate in any tissue or organ, can also spread and reproduce far away from their place of origin. The result: a metastasis.

Usually, every cell within the organism binds to its surrounding via specific adhesion receptors that are present on its plasma membrane. As universal "glue" between cells and their surroundings, these adhesion receptors, or integrins, either stabilize a cell if it needs to remain immobile, or serve as anchors when the cell climbs through the tissue. But how can certain types of cells such as white blood cells flexibly crawl through different tissues, although these tissues are composed of very distinct molecules that do not necessarily match the adhesion receptors?

Moving with and without a "glue"

The mystery has been solved in a recent Nature study by the group of Michael Sixt at the Institute of Science and Technology Austria (IST Austria) and collaborators from France. Combining experiments with physical models, the scientists describe a new mechanism of cell locomotion that works completely independent of a cell specifically binding to the extracellular environment. Instead, the cells use the geometry of the environment to propel themselves.

In their experiments, the biologists used different types of leukocytes from which they genetically eliminated the function of integrins to interrupt the binding between the cells and their extracellular environment. While integrins are essential for the survival and movement of almost all cell types, the IST Austria scientists had discovered in a previous study that leukocytes can move and survive without integrins. The same turned out to be true for some cancer cells.

Icy grounds ahead!

To analyze the locomotion mechanism that allows cells to migrate in the absence of adhesion, the scientists focused on the geometry of the environment rather than its molecular composition. They engineered tiny cell-sized "microfluidic" channels with different wall geometries: from completely smooth to rough or serrated texture. They then let the cells migrate through these channels to observe that the integrin-deprived cells were not able to move forward when the walls were smooth and parallel. "The cells were 'running on the spot'--just like a car tire would spin on icy grounds," says Anne Reversat, first author of the study and former IST Austria postdoc, who is now doing research at the University of Liverpool. "However, when the walls were textured with bumps, the cells could efficiently migrate without integrins. Cells that still carried their integrins could equally migrate in both rough textured and smooth channels."

The right grip to go everywhere

By looking closer experimentally and theoretically at the biomechanics of such "off-road" cell movement, Reversat et al. uncovered the unifying mechanical theme that underlies both modes of locomotion: Actin--the filamentous building material of the cell's cytoskeleton--flows from the front of the cell to the tail end. This "retrograde actin flow" is the force within the cell that, once coupled to the environment, drives the cell body forward. Force-coupling can happen via integrins that penetrate the plasma membrane and thereby connect the intracellular actin with the extracellular substrate.

As the scientists found, however, actin cannot only couple through integrins; it can also couple without any transmembrane receptors. Reversat: "The retrograde flow generates intracellular shear forces that push against the channel walls whenever there is a bump. If the walls are parallel, or the bumps are too far apart, this does not work. Another way to see this is that the cell propels itself by changing its shape over time. After all, leukocytes are amoeboid cells--'amoibos' being the Greek word for 'changing'. As the fine structure of tissues is geometrically very complex, amoeboid cells can always rely on this mode of locomotion. This makes them enormously adaptable. Essentially, they can go everywhere."

Researchers at Karolinska Institutet in Sweden have compared two ways of delivering cognitive behavioral therapy, CBT, to treat people with health anxiety, a condition that may increase in the wake of COVID-19. Out of about 200 study participants, half received CBT over the Internet and half were treated with conventional face-to-face CBT. The results, published in JAMA Psychiatry, show that Internet-delivered treatment had comparable effects, and could serve as an alternative to physical meetings in helping people who are worried about their health.

"The study is unique in that it is the first direct comparison of face-to-face CBT and Internet-delivered CBT for health anxiety," says Erik Hedman-Lagerlöf, professor of psychology and researcher at the Department of Clinical Neuroscience, Karolinska Institutet. "The results show that a treatment delivered exclusively online is sufficient to achieve tough and required behavioral changes. This is especially relevant now when the coronavirus pandemic limits our opportunities for physical meetings, while the fear of being affected by a severe health condition is discussed more frequently."

Health anxiety, also referred to as hypochondriasis, is characterized by an excessive and persistent fear or worry about serious illness. It often leads to significant suffering and functional impairment. , About 3.5 percent of the general population and up to 20 percent of patients in medical clinics are estimated to suffer from the condition, which causes great strain on the health care system.

In face-to-face CBT, which typically involves weekly sessions with a mental health clinician, about two thirds of patients respond to treatment. However, given the prevalence of health anxiety and scarcity of mental health professionals, the need for treatment far exceeds the availability of evidence-based face-to-face therapy. The researchers therefore wanted to examine the effect of an Internet-based treatment where the patient has access to information online and communicates regularly with a therapist through an email-like system. The patient also engages in behavioral changes in their day-to-day life, just as in the case of face-to-face CBT.

In the study, 204 adults with health anxiety were randomized to receive either face-to-face or Internet CBT for a period of 12 weeks. The participants were asked to rate their level of health anxiety each week using a standardized questionnaire commonly referred to as the Health Anxiety Inventory.

According to the researchers, Internet CBT had effects largely on par with the face-to-face treatment. This was despite the fact that the average Internet-therapist spent only 10 minutes per patient per week compared with about 45 minutes in the other group.

"One significant advantage is that the therapist can help more patients in the same time, but also that the treatment can be delivered regardless of the patient's geographical location, including to people living in rural areas," says Erland Axelsson, psychologist and researcher at the Department of Clinical Neuroscience, Karolinska Institutet. "The fact that you can access the content and communicate with your therapist at any time of the day also means that people who struggle to take time off from work can take part in treatment."

Another positive aspect of online CBT is that patients who are reluctant to seek psychological treatment due to perceived stigma may be more inclined to seek help, Erland Axelsson adds.

The study was conducted from 2014 to 2020 as a collaboration between Gustavsberg's primary care clinic and Karolinska Institutet. This research was financed by Karolinska Institutet, Region Stockholm, and Psykiatrifonden. Some of the authors have reported conflicts of interest including the co-authorship of a self-help book for health anxiety and shareholdings in a company specializing in online psychiatric symptom assessment.

What The Study Did: This study combined the results of 57 studies with 7,000 participants to examine how effective are interventions and programs to enhance the social, emotional and spiritual aspects of wisdom.

Authors: Dilip V. Jeste, M.D., of the University of California, San Diego in La Jolla, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamapsychiatry.2020.0821)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the articles for additional information, including other authors, author contributions and affiliations, conflicts of interest and financial disclosures, and funding and support.

A study led by researchers at the Babraham Institute in collaboration with the Wellcome Sanger Institute has uncovered how variations in a non-protein coding 'dark matter' region of the genome could make patients susceptible to complex autoimmune and allergic diseases such as inflammatory bowel disease. The study in mice and human cells reveals a key genetic switch that helps immune responses remain in check. Published today in the leading scientific journal Nature, the research, involving collaborations with research institutions in the UK and worldwide, identifies a new potential therapeutic target for the treatment of inflammatory diseases.

Over the last twenty years, the genetic basis of susceptibility to complex autoimmune and allergic diseases, such as Crohn's disease, ulcerative colitis, type 1 diabetes and asthma, has been narrowed down to a particular region of chromosome 11. This work has involved large scale genome-wide association studies (GWAS), a genome-wide 'spot-the-difference' comparison between the genomes of individuals with or without a disease, to highlight regions of variation in the DNA code. This can identify potential genetic causes, and reveal possible drug targets.

However, most of the genetic variations responsible for the susceptibility to complex immune and allergic diseases are concentrated within regions of the genome that don't encode proteins - the genome's 'dark matter'. This means there's not always a clear gene target for further investigation and the development of treatments.

Recent advances in sequencing-based approaches have shown that these disease-associated genetic changes are concentrated within regions of DNA called enhancers, which act as switches to precisely regulate the expression of genes. Further technological developments have allowed scientists to map physical interactions between different remote parts of the genome in 3D, so they can connect enhancers in non-coding regions with their target gene.

To gain insight into inflammatory disease, a large team of researchers used these methods to study an enigmatic non-protein-coding region of the genome whose genetic variations are associated with increased immune disease risk. They identified an enhancer element that is required for the immune system's 'peace-keepers' and immune response mediators, regulatory T cells (Tregs), to balance an immune response.

Lead researcher and Babraham Institute group leader, Dr Rahul Roychoudhuri said: "The immune system needs a way of preventing reactions to harmless self- and foreign substances and Treg cells play a vital role in this. They're also crucial in maintaining balance in the immune system, so that our immune responses are kept in check during infections. Tregs only represent a small percentage of the cells making up our complete immune system but they're essential; without them we die from excessive inflammation. Despite this important role, there has been little evidence that unequivocally links the genetic variations that cause certain individuals to be susceptible to inflammatory diseases to changes in Treg function. It turns out that non-protein-coding regions provided us with the opportunity to address this important question in the field."

Evolution gave the researchers a helping hand. The researchers took advantage of an approach called shared synteny, where not just genes are conserved between species, but a whole section of the genome. Similar to finding part of your book collection duplicated in your neighbour's house, including the order of their arrangement on the bookshelf.

They used this genomic similarity to translate what was known about the enhancer in the human genome and find the corresponding region in mice. They then explored the biological effect of removing the enhancer using mouse models.

The researchers found that the enhancer element controls the expression of a gene in Treg cells, which encodes a protein called GARP (Glycoprotein A Repetitions Predominant). They showed that deleting this enhancer element caused loss of the GARP protein in Treg cells, and an uncontrolled response to a triggered inflammation of the colon lining. This demonstrated that the enhancer is required for Treg-mediated suppression of colitis, with a role for the GARP protein in this immune system control.

There was a similar effect in human Treg cells from healthy blood donors. The researchers identified an enhancer region whose activity was impacted by genetic variation specifically in Treg cells. The enhancer directly interacted with the human form of the same gene, and the genomic variations occurring in the enhancer element were associated with reduced GARP expression.

Dr Gosia Trynka, a senior author on the paper from the Wellcome Sanger Institute and Open Targets, said: "Genetic variation provides important clues into disease processes that can be targeted by drugs. In our joint efforts here, we combined human and mouse research to gain invaluable insight into complex processes underlying immune diseases. This has identified GARP as a promising new drug target and brings us a step closer to developing more efficient therapies for people suffering from diseases such as asthma or inflammatory bowel disease."

Dr Roychoudhuri concludes: "Decades of research have now identified the variations in our genomes that make some of us more susceptible to inflammatory diseases than others. It has been very difficult, however, to make sense of how these variations relate to immune disease since many of them occur in non-protein-coding regions, and therefore the implications of these changes are poorly understood. Studies such as these will enable us to link the genetic switches that commonly reside in such disease-associated non-coding regions with the genes they control in different cell types. This will yield new insights into the cell types and genes underlying disease biology and provide new targets for therapeutic development."

What The Study Did: Professional medical societies recommend certain genetic tests for individuals with autism spectrum disorder (ASD). This study looked at how common it was for nearly 1,300 individuals diagnosed with ASD to undergo these tests and the factors associated with receiving genetic testing.

Authors: Eric M. Morrow, M.D., Ph.D., of Brown University in Providence, Rhode Island, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamapsychiatry.2020.0950)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the articles for additional information, including other authors, author contributions and affiliations, conflicts of interest and financial disclosures, and funding and support.

MINNEAPOLIS - It's never too late to lace up some sneakers and work up a sweat for brain health, according to a study published in the May 13, 2020, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study suggests older adults, even couch potatoes, may perform better on certain thinking and memory tests after just six months of aerobic exercise.

"As we all find out eventually, we lose a bit mentally and physically as we age. But even if you start an exercise program later in life, the benefit to your brain may be immense," said study author Marc J. Poulin, Ph.D., D.Phil., from the Cumming School of Medicine at the University of Calgary in Alberta, Canada. "Sure, aerobic exercise gets blood moving through your body. As our study found, it may also get blood moving to your brain, particularly in areas responsible for verbal fluency and executive functions. Our finding may be important, especially for older adults at risk for Alzheimer's and other dementias and brain disease."

The study involved 206 adults who prior to starting the six-month exercise intervention worked out no more than four days per week at a moderate intensity for 30 minutes or less, or no more than two days per week a high intensity for 20 minutes or less per day. They had an average age of 66 and no history of heart or memory problems. Participants were given thinking and memory tests at the start of the study, as well as an ultrasound to measure blood flow in the brain. Physical testing was repeated at three months, and thinking and physical testing repeated at the end of the six months.

Participants were enrolled in a supervised aerobic exercise program held three days a week. As they progressed through the program, they increased their workout from an average of 20 minutes a day to an average of at least 40 minutes. In addition, people were asked to work out on their own once a week.

Researchers found that after six months of exercise, participants improved by 5.7% on tests of executive function, which includes mental flexibility and self-correction. Verbal fluency, which tests how quickly you can retrieve information, increased by 2.4%.

"This change in verbal fluency is what you'd expect to see in someone five years younger," Poulin said.

Before and after six months of aerobic activity, the participants' average peak blood flow to the brain was measured using ultrasound. Blood flow rose from an average of 51.3 centimeters per second (cm/sec) to an average of 52.7 cm/sec, a 2.8% increase. The increase in blood flow with exercise was associated with a number of modest but significant improvements in aspects of thinking that usually decline as we age, Poulin said.

"Our study showed that six months' worth of vigorous exercise may pump blood to regions of the brain that specifically improve your verbal skills as well as memory and mental sharpness," said Poulin. "At a time when these results would be expected to be decreasing due to normal aging, to have these types of increases is exciting."

A limitation of the study was that the people doing the exercise were not compared to a similar group of people who were not exercising, so the results may have been due to other factors, although the researchers tried to control for this by testing participants twice over six months before the start of the program. In addition, some of the exercise was unsupervised, so the amount reported may be unreliable.

What The Review Says: The characteristics, treatment and outcomes of heart transplant recipients who were infected with COVID-19 in New York City are described in this case series.

Authors: Nir Uriel, M.D., M.Sc., of Columbia University Irving Medical Center and Weill Cornell Medicine in New York, is the corresponding author.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ 

(doi:10.1001/jamacardio.2020.2159)

Editor's Note: The article contains conflict of interest and funding/support disclosures. Please see the articles for additional information, including other authors, author contributions and affiliations, conflicts of interest and financial disclosures, and funding and support.

Doctors regularly warn their patients that having high levels of triglycerides, a major dietary fat, can increase the risk of heart disease, diabetes, obesity and fatty liver disease. There is considerable interest in finding novel ways to effectively regulate triglycerides in the blood to help manage these potentially life-threatening common conditions.

Now, researchers at Baylor College of Medicine, Princeton University and Texas A&M University are closer to achieving this goal after discovering the 3-D structure and mode of action of diacylglycerol O-acyltransferase-1 (DGAT1), the enzyme that synthesizes triglycerides and also is required for human dietary fat absorption and storage. DGAT1 is a known target to treat obesity and other metabolic diseases, so having a detailed understanding of what DGAT1 looks like and how it works opens opportunities for designing novel strategies for managing these conditions. The findings are published in the journal Nature.

"DGAT1 is a particularly interesting enzyme because it synthesizes triglycerides, which are the main component of hard fat, the type of fat usually found in the belly or midsection in our body. Triglycerides also are part of the particles that transport cholesterol - high-density lipoproteins (HDL, or 'good cholesterol'), and low-density and very-low-density lipoproteins (LDL and VLDL, or 'bad cholesterols')," said co-corresponding author Dr. Ming Zhou, Ruth McLean Bowman Bowers Professor in Biochemistry in the Department of Biochemistry and Molecular Biology at Baylor. "Learning to regulate this enzyme can help regulate fat synthesis and potentially manage related conditions."

Lie Wang, a graduate student in the Zhou lab, took the lead on this project. He applied cryo-electron microscopy, a technique that enables scientists to see how biomolecules move and interact as they perform their functions, to visualize the 3-D structure of DGAT1.

"This project was challenging because DGAT1 is embedded in biological membranes where it carries its function," Wang said. "We also developed an enzymatic assay, or test, to monitor the activity of DGAT1 in real time. Thanks to the integration of high-quality structure and precise functional studies we were able to unveil the structure of this important enzyme and gain novel insights into the mechanism of action."

DGAT1 is located in the membrane of the endoplasmic reticulum, a cellular structure engaged in the synthesis of proteins and lipids.

"It was exciting to discover that DGAT1 forms a large chamber inside the membrane, which was unexpected," Wang said. "This 'reaction chamber' isolates a space within the membrane where the enzymatic synthesis of triglycerides takes place."

"The reactants meet inside the chamber and that is where the reaction occurs. Then, the triglycerides bud-off the membrane in lipid droplets that carry them to where they are needed in the cell," Zhou said. "Neither this 3-D structure of DGAT1 nor its mechanism of action were known before in such detail."

This study not only reveals the structure and mode of action of a human enzyme that is essential for proper human metabolism, but it also enables researchers to explore the effects of molecules that interact with DGAT1 and potentially regulate its activity.

By studying samples from two independent clinical trials of malaria vaccines, Gemma Moncunill and colleagues have linked signatures in the immune system to better vaccine protection from the disease in children and adults. Their analysis of the RTS,S vaccine and sporozoite immunization provides generalizable benchmarks that future studies could use to evaluate the effectiveness of malaria vaccine candidates. Malaria continues to pose a huge health burden around the world, with an estimated 218 million cases in 2018. The RTS,S vaccine is the only candidate to have advanced far into clinical trials, but it has shown only modest protection. Researchers have also tested alternative strategies; one approach that combines weakened malaria parasites with preventative drug treatment (CPS immunization) displayed 100% efficacy in experimental trials in adults. Nevertheless, the rollout of a malaria vaccine has been seriously impeded by limited knowledge of the mechanisms of immunity, as well as by a lack of immune surrogates that can predict vaccine efficacy. Using transcriptional analysis of immune cells and systems biology techniques, Moncunill et al. examined blood samples from 24 adult volunteers who received CPS immunization and 255 African children who participated in a phase 3 trial of the RTS,S vaccine. The authors made some surprising findings; for example, children who received the RTS,S vaccine showed few changes in gene expression compared with those who received a nonprotective vaccine. However, the team did identify sets of genes that were linked to a protective response in the trials, observing that the receptor TLR4 and the protein NF-κB both played an important role. Some individuals also showed pre-immunization signatures that were linked to protection, a finding that could help identify non-responders who may benefit from immune priming or other interventions before vaccination.

In 2015 Francesco Greco, head of the Laboratory of Applied Materials for Printed and Soft electronics (LAMPSe) at the Institute of Solid State Physics at Graz University of Technology, developed so-called "tattoo electrodes" together with Italian scientists. These are conductive polymers that are printed using an inkjet printer on standard tattoo paper and then stuck to the skin like transfers to measure heart or muscle activity.

This type of electrode, optimised in 2018, opened up completely new paths in electrophysiological examinations, such as electrocardiography (ECG) or electromyography (EMG). Thanks to a thickness of 700 to 800 nanometres - that is about 100 times thinner than a human hair - the tattoos adapt to uneven skin and are hardly noticeable on the body. Moreover, the "tattoos" are dry electrodes; in contrast to gel electrodes, they work without a liquid interface and cannot dry out. They are excellently suited for long-term measurements. Even hairs growing through the tattoo do not interfere with the signal recording.

New generation of tattoo electrodes

Building on this pioneering achievement, Greco, together with Esma Ismailova (Department of Bioelectronics, École Nationale Supérieure des Mines de Saint-Étienne, France) and Laura Ferrari (The BioRobotics Institute, Scuola Superiore Sant'Anna, Italy), has now achieved a further milestone in the measurement of bioelectrical signals: the group has modified the tattoo electrodes in such a way that they can also be used in electroencephalography (EEG) - i.e. to measure brain activity.

To do this, the researchers used the same approach as in 2018, i.e. inkjet printing of conductive polymer on tattoo paper. The composition and thickness of the transfer paper and conductive polymer have been optimized to achieve an even better connection between the tattoo electrode and the skin and to record the EEG signals with maximum quality, because: "Brain waves are in the low frequency range and EEG signals have a very low amplitude. They are much more difficult to capture in high quality than EMG or ECG signals," explains Laura Ferrari, who worked on this project during her PhD and is now a postdoc researcher in France.

Tests under real clinical conditions have shown that the EEG measurement with the optimized tattoos is as successful as with conventional EEG electrodes. "Due to inkjet printing and the commercially available substrates, however, our tattoos are significantly less expensive than current EEG electrodes and also offer more advantages in terms of wearing comfort and long-term measurements in direct comparison," says Greco.

First ever MEG-compatible dry electrodes

The new tattoo electrodes are the very first dry electrode type that is suitable for long-term EEG measurements and at the same time compatible with magneto-encephalography (MEG). MEG is a well-established method for monitoring brain activity, for which so far only so-called "wet electrodes" can be used. Such electrodes work on the basis of electrolyte, gel or an electrode paste, and thus dry out quickly and are unsuitable for long-term measurements. The new generation of tattoo electrodes consists exclusively of conductive polymers, i.e. it does not contain any metals which can be problematic for MEG examinations, and is printed exclusively with inkjet. "With our method, we produce the perfect MEG-compatible electrode while reducing costs and production time," says Greco happily. The TU Graz researcher is currently spinning ideas on how this technology can be used in clinics and in neuroengineering as well as in the field of brain computer interfaces.

Viruses are ubiquitous pathogens that cause severe infectious diseases in both humans and agricultural crops. As most viruses have simple genomes and encode only a few proteins, they must usurp host cell resources for propagation. Understanding what host processes are disrupted and which viral proteins are involved greatly facilitate the design of therapeutic measures for controlling viral diseases in humans and crop plants.

Recently, researchers from the Institute of Genetics and Developmental Biology (IGDB) of the Chinese Academy of Sciences discovered a plant viral protein named 17K that disrupts host cell division to promote its own propagation in infected tissues. They also linked it structurally to certain animal virus proteins.

The work was published online in Science Advances on May 13. It is the result of a decade-long collaboration between the IGDB group led by Dr. WANG Daowen and the laboratory of Dr. ZHAO Yuqi at the School of Medicine of the University of Maryland.

The 17K protein is conserved in a group of cereal-infecting viruses called barley yellow dwarf viruses (BYDVs). Even though BYDVs have been studied for more than 60 years, they frequently cause severe epidemics in global wheat, barley, maize and oat crops, with yellowing and dwarfing as typical results.

The researchers hypothesized that one or more BYDV proteins may inhibit host cell growth by disrupting cell division, a fundamental process required for plants and animals to grow, develop and reproduce.

By testing seven BYDV proteins individually in fission yeast - a model for cell division studies - 17K was found to be the only BYDV protein capable of inhibiting cell growth.

Through detailed molecular genetic and biochemical analyses, the researchers found that the 17K protein can disrupt cell division, and thus cell proliferation, on its own as well as in barley plants naturally infected by BYDV. They further showed that 17K perturbed the function of Wee1-Cdc25-Cdc2/Cdk1, a molecular switch for the orderly progression of cell division in both plants and animals.

Since the study's datasets are all consistent with the idea that 17K - by its ability to disrupt cell division - is a key factor in promoting [or eliciting] host dwarfism by BYDVs, 17K may be a future target in BYDV control.

Notably, the researchers observed that BYDV 17K resembles several animal viral proteins, e.g., the Vpr protein of human immunodeficiency virus 1 (HIV-1) and the p17 protein of avian reovirus (ARV), in the inhibition of cell division and growth.

These three viral proteins represent a novel class of cell division regulators conserved between unrelated plant and animal viruses. They share similarities in secondary structure as well as some amino acid residues crucial to disrupting cell division. How they evolved and their implication for comparative studies of plant and animal viral pathogenesis are interesting questions for further research.

Microplastics are everywhere - including in our drinking water, table salt and in the air that we breathe. Having studied the scope of microplastics in a number of countries, researchers are worried.

- Given the lifetime inevitable exposure to microplastics, we urgently call for a better understanding of the potential hazards of microplastics to human health, says Dr Elvis Genbo Xu, an Assistant Professor of environmental toxicology at the University of Southern Denmark.

There are many studies on microplastics, especially concerning the oceans, but in this study Elvis Genbo Xu and his colleagues, Professor Huanghong Shi from East China Normal University and Professor Eddy Zeng from Jinan University in China, chose to focus on microplastics in table salt, drinking water and air.

In honey, milk and beer

- Microplastics have been found in many places, including in various foods such as honey, milk, beer and seafood, but these are foods that you can choose not to eat - unlike salt, water and air, which no one can avoid, and that's why we're focusing on these, he says.

The researchers have conducted a so-called meta-analysis. This means they have reviewed 46 existing scientific articles on the subject while looking for trends and patterns.

They conclude, among other things, that of the three sources of microplastic intake, the primary one is air; especially indoor air.

We inhale microplastics

- When we inhale microplastics, the tiny particles can reach the lungs and digestive system. Nobody knows what this means for the human organism and our health, but as we are talking about a lifelong exposure, it's a cause for concern, says Elvis Genbo Xu.

There are no official guidelines for how much microplastic food may contain. Likewise, no studies have defined values for when certain sizes or amounts of microplastic particles can be hazardous for humans to ingest.

However, animal studies show that the ingestion of microplastics can disturb, for example, the metabolism and intestinal system.

Table salt:

More than 100 different products from around the world have been examined for microplastics, and there is a huge difference between them.

Microplastics do not come from the salt itself, but are added during drying, production, packaging and transport.

- Our advice is that consumers should be aware of the way food is produced and processed, because it is probably not only in the production and packaging of table salt that microplastics enter the finished product that reaches the supermarket shelves, says Elvis Genbo Xu.

High concentrations of microplastics in table salt have been found in Croatia, Indonesia, Italy, USA and China. Conversely, concentrations are low in Australia, France, Iran, Japan, Malaysia, New Zealand, Portugal and Africa.

There are no studies of table salt in Denmark.

Drinking water:

The occurrence of microplastics is greatest in water from recycled plastic bottles. The microplastics may originate from one or more steps in the water supply chain, from the plastic bottle itself or from its screw cap.

The researchers were surprised to find microplastics in water sold in glass bottles. One possible source is the plastic cap, which can release microparticles when screwed off and on the glass bottle.

- We believe that packaging is a major source of microplastics in bottled drinking water, says Elvis Genbo Xu.

Microplastics have also been found in tap water, which Danes drink a lot of. The microplastics stem from, for example, contaminated drinking water sources such as lakes, groundwater and rivers, but may also come from the water processing plants. There is a huge difference between where and how much microplastic has been found in different countries. In Denmark and Italy, the scope is low.

- Some of the plastics registered in tap water in different countries are quite large pieces, up to 5 mm. Such large pieces may be captured by a water purifier equipped with a membrane filtre. Another way to reduce exposure to microplastics in drinking water is to avoid drinking bottled water, says Elvis Genbo Xu.

Air:

In air, the sources are primarily synthetic textiles, rubber tyres and road dust. Other sources include furniture, building materials, waste incineration, landfills and industrial waste.

The weather has a major influence on where the microplastic particles can be found, but the concentration tends to be higher in wet weather than in dry weather.

The air can release particles in the form of dust, which especially young children may ingest when they put things in their mouths.

- I am more worried about indoor air than outdoor air. Indoors, we have particles from all the household plastic products. You cannot avoid them all, but it is possible to minimise the exposure. Let in some fresh air and don't buy synthetic fabrics and other plastic products like toys, furniture and food containers, says Elvis Genbo Xu.