We see amazing scientific breakthroughs every day and these help us understand our bodies better and learn to treat them better. As per the latest news from the Langone Medical Center at NYU, the scientists there have found two genes that create the neuronal circuits essential for breathing. This new information could be very helpful when it comes to advancing treatments in the field of neurodegenerative diseases like ALS that is responsible for killing neurons which control muscle movement required for eating, breathing and even in moving. The find will also help advance treatments in the field of spinal cord injuries.
The study has found that there is code in the molecules that identifies a phrenic motor column (PMC) – which is a group of nerve cells that control the muscles and these are present in out body almost halfway up in the back of our neck, above our fourth cervical vertebra and are considered to be very important motorneurons in the body and that is clear by their function, if these neurons were to malfunction, we could face troubles performing basic tasks and in some cases even breathing could become difficult. Jeremy Dasen, who is a member of Howard Hughes Institute and the assistant professor of psychology and neuroscience indicates that the normal functioning of these neurons is very important for us to function normally and independently. Jeremy Dasen has also led a three year long study with Dr. Polyxeni Philippidou.
The find indicates that if these neurons are harmed a lot of damage can happen to the body instantly and any harm to the spinal cord that has these neurons can immediately shut down breathing, that is how important this discovery is. If the PMC neurons degenerate then they could lead to death in patients who have ALS or injuries of the spinal cord.
The scientists have still not identified how these PMC neurons can be identified from the others present in the body and how these neurons can develop themselves in the fetus’s diaphragm. However, we do know that these PMC neurons make sure that there is a regular flow of electrochemical signals through their axons that are bundled and to the muscles of the diaphragm and this process makes it possible for the lungs to relax and expand to make natural breathing possible. Dr. Dasen states that they have found a set of markers for the neurons that can identify the cells from all the other neurons so it has become easy to study them with a lot of focus and find newer ways to selectively make the chances of their survival better and healthier.
To further understand how the PMC neurons can be distinguished from the other spinal cord neurons, Dr. Philippidou started the process by injecting a fluorescent tracer in the phrenic nerve in transgenic mice. This nerve connects the PMC neurons to the diaphragm and after injecting the tracer, Dr. Philippidou looked for all the neurons in the spine that light up while the tracer travelled towards the PMC. The reason for using transgenic mice was that they express the green fluorescent protein (GFP) in their neurons and their axons. This made it possible for the scientists to view the phrenic nerve. After the pattern of expression of the genes was identified, Dr. Philippidou started identifying the specific roles that they play. After much research, he came across a complex strain of these mice that were transgenic and also considered the results received from the mice provided through another collaborator Lucie Jeannotte, at University of Quebec. Two genes, called Hoxa5 and Hoxc5 came out as the major controllers in the proper development of PMC. It is important to know here that the Hox genes are responsible for gene regulation in animal development and in humans there are 39 of them expressed. In mice, it was noticed that when these two genes are silenced,the PMC becomes unable to form their highly complex and tight columnar organization and is unable to connect with the diaphragm…this leads to the newborn not being able to breathe at all.
Dr. Dasen says that if these genes are deleted in late fetal development as well the PMC neuron numbers drop and the nerve under discussion cannot form enough to create enough branches to reach the diaphragm muscles. The plan as per Dr. Dasen is to utilize the findings to understand the entire process of breathing better. This would include the neurons that generate rhythm in the brain stem that respond to the levels of carbon dioxide, understand stress, and also other factors in the environment. He also says that now they know more about the PMC cells and are better equipped to understand how breathing works and how all the connections form. Both the scientists are hopeful that once a deeper understanding to the respiratory network and the way it is formed is created, then better ways to treat breathing disorders can be created and used.
Even though Dr. Dasen lost most of his research to Hurricane Sandy while the research was still on and in its final stages, he had shipped some of them to Quebec and that helped reach the final stages and to complete the research that will in the future benefit a very big population.