Wellcome Trust Research Round-up: 09.05.2016
Our round-up of news from the Wellcome Trust research community.
Labradors may be prone to becoming overweight due to a newly identified gene variant that is associated with obesity and appetite.
The UK’s most popular dog breed has long been associated with obesity, despite their diets being controlled by their owners. Wellcome-funded researchers studied 310 dogs to identify the presence of three possible obesity-related genes. They also questioned the owners about their dogs’ behaviour to assess ‘food motivation.’
The researchers found that one gene variant – called POMC – was very strongly associated with weight, obesity and appetite in these dogs. For each copy of the gene variant the dog carried, they were on average 1.9kg heavier than their counterparts without it. The gene this variant affects is also known to play an important role in how the brain recognises hunger and feeling full in humans.
The findings go some way to explaining why Labradors make such good working dogs; they are often trained with food as a reward and this gene variant could make them more motivated to work for it.
Professor Stephen O’Rahilly, Co-Director of the Wellcome Trust-Medical Research Council Institute of Metabolic Science explains how the results of this study could also have implications for humans: “Common genetic variants affecting the POMC gene are associated with human body weight and there are even some rare obese people who lack a very similar part of the POMC gene to the one that is missing in the dogs. So further research in these obese Labradors may not only help the wellbeing of companion animals but also have important lessons for human health.”
This research is published in Cell Metabolism.
Scientists at the Wellcome Trust Sanger Institute have grown and catalogued more than 130 bacteria from the human intestines to help us understand how they keep us healthy.
In research published in Nature, scientists have developed a method to culture these bacteria in a laboratory. Until now this had been a difficult process as many of the bacterial species are sensitive to oxygen.
Approximately 2% of a person’s body weight can be attributed to bacteria, and imbalances in this microbiome can lead to syndromes and diseases like Irritable Bowel Syndrome, allergies and obesity. By culturing these essential bacteria in a lab, scientists can sequence their genomes and try to create tailored treatments using specific bacteria.
Dr Trevor Lawley, group leader at the Sanger Institute said: “Being able to cast light on this microbial ‘Dark matter’ has implications for the whole of biology and how we consider health. We will be able to isolate the microbes from people with a specific disease, such as infection, cancers or autoimmune diseases, and study these microbes in a mouse model to see what happens. Studying our ‘second’ genome, that of the microbiota, will lead to a huge increase in our understanding of basic biology and the relationship between our gut bacteria and health and disease.”
Memories are replayed and stored in a different part of the brain to where they are formed, according to a new Wellcome-funded study in rats.
The team studied ‘place cells’ in the rats’ hippocampus, an area of the brain important for forming memories, and in the ‘grid cells’ of the entorhinal cortex. The Rats’ brain activity was monitored as they ran along a track for 30 minutes, before resting for 90 minutes.
Activity in the place cells showed the rats replaying their movements on the track in their mind at speeds 10-20 times faster than reality. This activity was also seen with only a 10 millisecond delay in grid cells in a different area of the brain, suggesting that memories are transferred quickly from one area to another.
The study, published in Nature Neuroscience, suggests that replaying memories during rest is essential for consolidating memories. It could offer clues to why people with Alzheimer’s can often recall childhood memories, but not recent ones, as the hippocampus and entorhinal cortex areas of the brain are some of the first to be damaged by the disease.
Wellcome Fellow Dr Caswell Barry from the department of Cell & Developmental Biology at UCL said: “This is the first time we’ve seen coordinated replay between two areas of the brain known to be important for memory, suggesting a filing of memories from one area to another. The hippocampus constantly absorbs information but it seems it can’t store everything so replays the important memories for long-term storage and transfers them to the entorhinal cortex, and possibly on to other areas of the brain, for safe-keeping and easy access.”
A new weapon against Zika
Wolbachia, a naturally occurring bacterium, has been found to be a critical weapon in combatting the spread of Zika virus according to new research published in Cell Host and Microbe.
Insects that are infected with Wolbachia are unable to transmit certain viruses as the bacterium prevents the virus particles replicating within the insect. The bacterium is already known to inhibit the transmission of Dengue virus and was therefore predicted to be effective against the closely-related Zika virus.
Wellcome-funded researchers fed wild mosquitos and Wolbachia-infected mosquitos with blood containing two recently-circulating strains of the Zika virus from South America. The mosquitos infected with Wolbachia had a greatly reduced amount of virus in their saliva compared to the field mosquitos. It is the first published report on the use on Wolbachia against Zika and suggests that the bacterium might be able to block Zika transmission in the field.
Lead scientist Professor Scot O’Neill from Monash University said: “The method we’re using is safe for humans and the environment, and has received widespread international support from governments, regulators and community members. With additional studies testing Zika and Wolbachia also underway in Singapore and Colombia, we’re well positioned to be part of global efforts combining traditional and new approaches to stop the spread of Aedes-borne viral diseases.”
Other Wellcome Trust research news
- Scientists have developed a new technique to allow embryos to survive and develop in vitro (outside the body) past the implantation stage. Research into this crucial stage of human development has been hindered as it has previously been impossible to carry out studies on embryos past the point at which they would normally implant in the womb. Published in Nature, this technique will allow scientists to culture embryos up to day 13 of development, a day under the UK legal limit.
- Five new genes associated with breast cancer have been identified by researchers at the Wellcome Trust Sanger Institute, in the largest-ever breast cancer sequencing study to date. As well as the five genes, the analysis of 560 breast cancer genomes also found 13 new mutational signatures that can influence tumour development. The results, published in Nature and Nature Communications reveal more about the highly individual nature of breast cancer genomes and suggest a role for more personalised treatment of these tumours.
- Antibiotic drug-resistant epidemics could be tackled in real time by combining DNA sequencing and laboratory tests with internet-based location tracking and computer analysis. Researchers developed an on-line tool called Microreact and studied the emergence and transmission of the ‘superbugs’ MRSA (methicillin-resistant Staphylococcus aureus) and MSSA (methicillin-susceptible Staphylococcus aureus) across 450 hospitals in Europe. This research is published in mBio.
- A new class of drug could offer hope to men with aggressive prostate cancer that has stopped responding to conventional treatment. Wellcome-funded researchers studied a type of drug called Hsp90 inhibitors which target the mechanism that prostate cancer cells use to evade normal treatment methods. This research is published in Cancer Research.
Image credits: RobotEwok via Flickr, CC-BY-NC-ND; SEM of E. coli, Debbie Marshall, Wellcome Images; Human brain cells, Spike Walker, Wellcome Images; Aedes aegypti mosquito, Sanofi Pasteur via Flickr, CC-BY-NC-ND