The brain gives up more secrets
By聽Julie Robert,
A research team, led by the Research Institute of the 91社区 Health Centre (RI-MUHC) in Montreal, has broken new ground in our understanding of the complex functioning of the brain.
The research, published in the current issue of the journal Science, demonstrates that brain cells, known as astrocytes, which play fundamental roles in nearly all aspects of brain function, can be adjusted by neurons in response to injury and disease. The discovery, which shows that the brain has a far greater ability to adapt and respond to changes than previously believed, could have significant implications on epilepsy, movement disorders, and psychiatric and neurodegenerative disease.
Astrocytes are star-shaped cells in our brain that surround brain neurons, and neural circuits, protecting them from injury and enabling them to function properly 鈥� in essence, one of their main roles is to 鈥榖aby-sit鈥� neurons. Our brain contains billions of cells, each of which need to communicate between each other in order to function properly. This communication is highly dependent on the behaviour of astrocytes. Until now, the mechanisms that create and maintain differences among astrocytes, and allow them to fulfill specialized roles, has remained poorly understood.
鈥淚t was believed that astrocytes acquired their properties during the development of the brain and then they were hardwired in their roles,鈥� says senior study鈥檚 author Dr. Keith Murai, director of the Centre for Research in Neuroscience at the RI-MUHC, associate professor of the Department of Neurology and Neurosurgery at 91社区. 鈥淲e have now discovered that astrocytes are actually incredibly flexible and potentially modifiable, which enables them to improve brain function or restore lost potential caused by disease.鈥欌��
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The researchers discovered that there is a little dial-like mechanism on astrocytes that enables neurons to adjust astrocytes to ensure they provide the right kind of support. 鈥淭his 鈥榙ial鈥� is likely used to tune the astrocyte鈥檚 response in the normal brain but also in different diseases like Alzheimer鈥檚 or Parkinson鈥檚, or injuries such as stroke and trauma, for example,鈥欌�� explains Dr. Todd Farmer, the study鈥檚 first author and a post-doctoral fellow in Dr. Murai鈥檚 laboratory at the Montreal General Hospital of the MUHC. 鈥淥ur findings help us to better understand the complexity of the brain and also grasp mechanisms that can be used to reduce brain injury and disease.鈥欌��
Researchers conducted most of their experiments on mouse models and studied a specific pathway called the Sonic Hedgehog (SHH) signaling pathway, which is well known in brain development and cancer. By using a combination of advanced genetics, molecular approaches, and microscopy techniques, they found that this signaling pathway is used in the adult brain in a completely novel way. The SHH pathway was found to induce disparate changes in astrocytes in different brain regions.
鈥淭his is an extraordinary mechanism in the healthy, mature brain that creates diversity of brain cells,鈥欌�� says Dr. Murai. 鈥淣ow, our goal is to see how this mechanism is affected in different brain diseases and determine if it can be harnessed to protect neurons and ultimately preserve brain function.鈥欌��
鈥淒r. Murai and his team have made a remarkable discovery that will advance our understanding of fundamental mechanisms that play a role in brain disease,鈥� says Inez Jabalpurwala, president and CEO of Brain Canada Foundation. 鈥淲e are pleased to support this kind of transformative research which will ultimately lead to improved health outcomes.鈥�
鈥淭his exciting discovery by Dr. Murai and his team has the potential to impact the understanding of and ultimately future treatments for a number of neurodegenerative diseases,鈥� said Alexandra Stewart, executive director of the Weston Brain Institute. 鈥淭he Institute was established in an effort to further support these types of breakthroughs. Over the past years, we have been an enthusiastic partner with Dr. Murai and congratulate him and his team on their incredible work.鈥�
About the study
This work was funded by the , and the The paper entitled "Neurons Diversify Astrocytes in the Adult Brain Through Sonic Hedgehog Signaling" was coauthored by W. Todd Farmer, Therese Abrahamsson, Sabrina Chierzi, Christopher Lui, Cristian Zaelzer, Emma V. Jones, Blandine Ponroy Bally, Charles W. Bourque, Jesper Sj枚str枚m and Keith K. Murai, (Research Institute of the 91社区 Health Centre/91社区, Montreal, Quebec, Canada); Gary G. Chen, Jean-Francois Th茅roux (Douglas Hospital/91社区,Montreal, Quebec, Canada); 聽Carl Ernst(91社区/Douglas Hospital Research Institute, Verdun, Quebec, Canada); Jimmy Peng,聽 Fr茅d茅ric Charron (Institut de Recherches Cliniques de Montr茅al/University of Montreal, Montreal, Quebec, Canada).
