New research finds mice with mutations in a gene for autism develop too many connections between their neurons when they have the gene altered. Communication malfunctions among neurons seems to be at the root of autism, according to recent findings.
In a study at Washington University School of Medicine in St. Louis, researchers suggest that a defective gene may lead to autism by affecting how neurons connect and communicate with each other in the brain. The mice that lack the gene form overly complicated connections between brain neurons and are unable to learn. Researchers revealed their findings in a November publication. A pair of recent studies, published in Nature Communications, suggest that some of the diverse symptoms associated with autism may result from a malfunction in brain cell communication. The study raises the possibility that patients with autism may have too many synapses in their brains,” said senior author Azad Bonni, MD, PhD, the Edison Professor of Neuroscience and head of the Department of Neuroscience at Washington University School of Medicine in St. Louis. “The increased number of synapses can lead to miscommunication between neurons in the developing brain, which can lead to learning impairments, although we don’t know how.” Autism is a neurodevelopmental disorder that affects about one child out of every 70. Social and communication problems are significant features of this condition.
Six genes involved in attaching a molecular tag to proteins, called ubiquitin, have been linked to autism in people. A group of genes called ubiquitin ligases work as a kind of work order, instructing the rest of the cell how to handle the proteins tagged The one being discarded should be redirected to another part of the cell, and the one being rerouted to a different part of the cell needs its activity adjusted. There may be a mutation in one of the ubiquitin genes in patients with autism that causes it not to work However, it is unclear which types of tagging proteins affect the structure and function of the brain, and why such problems could be linked to autism. In order to study the influence of ubiquitin genes on brain development, Bonni, Valnegri, and colleagues removed the ubiquitin gene RNF8 from cerebellum neurons in young mice. The cerebellum is one of the key brain regions implicated in A study published in Science found that neurons lacking the RNF8 gene were found to form about 50 percent more synapses — the connections that allow neurons to send signals to one another. It worked with the extra synapses. In the mice whose signals were weak due to the lack of the protein, the researchers found that the electrical signal was enhanced by two times. Among other things, the cerebellum is responsible for movement and learning motor skills like riding a bike. The incoordination of movement that is a hallmark of autism and a tendency for people to walk on tiptoes are two such symptoms.
It is not clear that the animals without the RNF8 gene in the neurons of their cerebellum had any A normal stride and good coordination could be seen in their movements. Researchers found that both mice without RNF8 and those that were naturally bred failed miserably at learning motor skills. By using a quick puff of air to the eye, researchers got the mice to connect a blinking light with a puff of air. It is a well-known fact that mice learn to close their eyes to avoid the irritation of the air puff coming from the light blink.
Language delays and intense concentration on objects or topics that are of interest to people with autism are common characteristics. According to the researchers, the cerebellum may contribute to not only motor learning, but that of other symptoms exhibited by people with autism as well. Of course, a mouse that can’t learn to close its eyes is very different from a person with autism who has difficulty communicating. They noted, however, that the finding suggested that increasing or decreasing the number of connections neurons make with each other can have significant In addition to testing the other autism-associated ubiquitin genes since Bonni and colleagues wrote this paper. A rise in the number of synapses in the cerebellum was observed when all the genes tested were suppressed. Bonni said it’s “possible that excessive connections between neurons are contributing to autism.” More study needs to be done on people to verify this hypothesis, but if that does turn out to be true, then researchers can start looking for ways to control There is a potential benefit not just to people with rare mutations in ubiquitin genes but to the greater autism community as well.”