Science: scientists from Zhejiang University reveal that microglia play a key role in memory regulation

February 10, 2020 / Bio Valley bio on / - -- microglia are the resident immune cells in the brain, they are the first responders, always looking for the place where something goes wrong They make up about 10% of our brain cells In the past, they were thought to be passive bystanders in the brain, working only when injured or infected These cells were first observed by Rudolf Virchow, a German doctor, in 1856 They were later called microglia, meaning "little glue" Now, in a new study of mice, researchers from the medical school of Zhejiang University in China have found that microglia may actually be a key factor in memory retention If the same effect is found in humans, it could lead to better treatments for amnesia, Alzheimer's and other memory impairing diseases The relevant research results were published in the Science Journal on February 7, 2020, and the title of the paper is "microglia mediate forcing via complex dependent synthetic elimination" Rat microglia (green), image from Wikipedia, CC by-sa Microglia have many functions When there is injury or infection, they play a positive role in inhibiting brain response But scientists are increasingly aware that microglia have many functions Our brains are a mixture of dead cells and accumulated chemicals that need to be removed The task of microglia is to keep our brain clean and healthy Scientists have also recently discovered that microglia are involved in maintaining connections between nerve cells (called synapses) These synapses are vital communication hubs for brain cells to talk to each other and transmit brain signals In particular, during brain development, microglia actively clear or "prune" synapses, which helps shape circuits that allow the brain to work effectively In fact, it's the connections between these neurons that keep our memory alive, and they're vulnerable to diseases that affect our memory, such as Alzheimer's disease Therefore, the whole scientific community is increasingly interested in these cells and their potential to provide new targets for the treatment of complex brain diseases such as Alzheimer's disease Indeed, one gene known to increase people's risk of Alzheimer's disease is TREM-2, which encodes a protein found in microglia The new study of memory retention shows that microglia are closely related to memory retention in mice Mice experienced the fear conditioning task, so that when they were placed in an environment where they remembered experiencing something negative - in this study, when they were given a small shock to their feet - they would stay still because of fear Over the course of 35 days, the mice 'freeing response decreased from 70% to 20%, indicating that they had forgotten the negative effects of this particular environment Then, using a series of scientific tools, including genetic, pharmacological and biochemical methods, the authors removed microglia from the brains of these mice and carried out experiments again The results showed that the removal of microglia changed their response to this task About 50% of the mice (20% in the above experiments) remembered the negative experience even after a similar period of time Based on this, a hypothesis is put forward that microglia is the key to consolidate these memories and support which memories are forgotten and which memories are kept The study continued to find that it was the synaptic rearrangement within these mice that led to this observation Although this is an exciting study for the scientific community, what does it mean to improve our understanding of the human brain and our ability to forget? It's important to remember that the situation in the human brain is likely to be completely different Now more and more evidences show that there are obvious differences between mouse and human microglia These existing studies have observed the composition of microglia in human and mouse, and found that they react differently to injury This means that their responses to brain maintenance may also be very different Therefore, although it seems that the functional description of microglia is a little more complicated, the mystery surrounding human microglia and its role in forgetfulness still need to be explored However, as genetic research suggests, these cells may play an important role in human memory function (bio Com) reference: 1 Chao Wang et al Microglia mediate forcing via complex dependent synthetic killing Science, 2020, DOI: 10.1126/science.aaz2288 2 Study in micro: brain cells long thought of as passive play key role in memory https://mediaexpress.com/news/2020-02-micro-brain-cells-thought-passive.html