A mode of communication between neurons and microglia, immune cells present in the brain, has just been discovered and would provide a better understanding of multiple sclerosis.
- A mode of communication has been discovered between neurons and microglia, immune cells present in the brain.
- This could lead to a better understanding of the disease of multiple sclerosis and perhaps, in time, to the development of new treatments.
According to federation for brain research, the mammalian brain contains between 100 million and 100 billion neurons depending on the species. For humans, this figure is estimated between 86 and 100 billion. Neurons are specialized cells responsible for transmitting information to other cells. But, other cell types exist in our cranium, such as glial cells, which have an important role in cleaning up cellular debris and transporting nutrients to neurons or microglia, immune cells. Researchers have just discovered, for the first time, an interaction between neurons and microglia. Their work has been published in the journal NatureCommunications.
Five essential elements for the transmission of the nervous message
To understand this discovery, you must first understand how the transmission of a nervous message takes place. Neurons send it. This first passes through the axons (the extension of the neurons) which are surrounded by myelin, a kind of protective membrane. Myelin insulates and protects nerve fibers in the brain and is essential to the central and peripheral nervous system, particularly for the conduction of nerve messages. Then there are the nodes of Ranvier, located between the myelin segments. They play a key role in the rapid dissemination of information.
In summary, there are therefore four essential elements for the transmission of a nervous message: the neuron, the axon, the myelin and the nodes of Ranvier. Researchers from the National Institute for Health and Medical Research (Inserm), the National Center for Scientific Research (CNRS), the Assistance Publique – Hôpitaux de Paris (AP-HP) and Sorbonne University have just discover a fifth cell involved in this process: the microglia. These are immune cells that protect the brain and are involved in regenerative processes such as remyelination, ie the production of myelin, which decreases in pathologies such as multiple sclerosis. According to the scientists, the contacts between the neurons and the microglia would take place at the level of the nodes of Ranvier.
An important discovery to better understand multiple sclerosis
To achieve this result, work was carried out on mice and human tissues. They thus observed interactions between neurons and microglia. These were particularly important during the regeneration of myelin. According to them, “it is neural activity that mediates and reinforces the interaction. The microglia are able to “read” the information that arrives at the nodes of Ranvier in the form of an ionic signal, thus modulating their state and their interaction with the neuron. An alteration of this ionic signal can maintain microglia in a pro-inflammatory state, preventing them from playing their pro-regenerative and pro-remyelinating role”.
In other words, when microglia no longer fulfill their regenerative role, it could be due to this interaction with neurons. This discovery is particularly important for future research on the disease of multiple sclerosis. It could make it possible to better understand this pathology and perhaps, in the long term, to develop new treatments which would act on microglia to increase their pro-regenerative role.
.