03-03-2005, 02:12 PM
The causes of autism have baffled the medical world for years; now, researchers at Columbia University Medical Center have characterized a cellular defect that may begin to explain the disease.
The study, conducted by Peter Scheiffele, assistant professor of physiology and cellular biophysics, examined how brain cells form synapses during development and identified molecules involved in this process. His research indicated that a defective neuroligin gene, which affects the firing of neurons, might be related to autism.
While previous human genome research has indicated that patients with autism have a genetic defect that people without autism do not, Columbia scientists have now shown how this defective gene affects neuronal connectivity.
Autism is a disorder of the nervous system that affects communication and social skills. It develops after birth as the brain forms many of its neural connections, and therefore most signs of autism do not appear until age two.
“We know only very little about the autistic brain, but now at least we can start from the cellular level. Now, we can ask how this affects circuits and development,” Scheiffele said.
Neurons receive both excitatory and inhibitory inputs that determine whether or not the neuron will fire; with a defective neuroligin gene, Scheiffele’s study found that the balance of these inputs is disturbed and thus the process of information is inhibited. When the neuroligin gene is defective, the cell does not form as many connections, or synapses, as it would normally These results indicate the essential nature of neuroligin in synapse formation.
“It feels great to have the study published as a student,” said Ben Chih, graduate student in the department of physiology and cellular biophysics, “to know that other scientists in the field also think the study is good.” Chih performed the research for the study, which was recently published in the journal Science.
Understanding these cellular defects brings researchers one step closer to finding a possible cure for autism, but Scheiffele explains that much more research needs to be done. “We need to learn more on multiple levels. The neuroligin is only one group of genes associated with autism. It is not the whole story,” Scheiffele said. “We need better genetic studies and identification of genetic defects. This highlights how important it is that more funding be made available. I don’t want to give any false hope” about when a cure might be discovered.
Chih plans to expand his research in the future. “I am continuing this study focusing on neuroligin’s role in an animal model,” he said. “Now we are making mutant mice that lack neuroligin protein and see if they would have behavioral defects.”
Autism research is particularly important today. In the last 15 years, there has been an increase in the number of children with autism, and research indicates that one in every 150 children in the United States may be affected.
“It is not completely clear what the cause is or if the numbers are correct, but the numbers are alarming,” Scheiffele said.
The study used primary neurons from the hippocampus of embryonic rats, which enabled Scheiffele’s team of researchers to obtain precisely and directly manipulate the cellular function. Scheiffele and Chih found that rat neurons without neuroligin have altered connections similar to those in children with autism.
“Columbia has a very strong group of researchers studying many different aspects of autism,” Scheiffele said. Besides developmental biologists like Scheiffele, these include researchers who use functional imaging to explore which brain areas are activated when individuals engage in social interactions, and researchers who examine the potential influence of environmental factors, such as viral infections and toxins on neuropsychiatric disorders.
The project received funding from the National Alliance for Austistic Children and the National Institute for Neurological Disorder and Stroke.
http://www.columbiaspectator.com/vnews/d...5780641d9b
The study, conducted by Peter Scheiffele, assistant professor of physiology and cellular biophysics, examined how brain cells form synapses during development and identified molecules involved in this process. His research indicated that a defective neuroligin gene, which affects the firing of neurons, might be related to autism.
While previous human genome research has indicated that patients with autism have a genetic defect that people without autism do not, Columbia scientists have now shown how this defective gene affects neuronal connectivity.
Autism is a disorder of the nervous system that affects communication and social skills. It develops after birth as the brain forms many of its neural connections, and therefore most signs of autism do not appear until age two.
“We know only very little about the autistic brain, but now at least we can start from the cellular level. Now, we can ask how this affects circuits and development,” Scheiffele said.
Neurons receive both excitatory and inhibitory inputs that determine whether or not the neuron will fire; with a defective neuroligin gene, Scheiffele’s study found that the balance of these inputs is disturbed and thus the process of information is inhibited. When the neuroligin gene is defective, the cell does not form as many connections, or synapses, as it would normally These results indicate the essential nature of neuroligin in synapse formation.
“It feels great to have the study published as a student,” said Ben Chih, graduate student in the department of physiology and cellular biophysics, “to know that other scientists in the field also think the study is good.” Chih performed the research for the study, which was recently published in the journal Science.
Understanding these cellular defects brings researchers one step closer to finding a possible cure for autism, but Scheiffele explains that much more research needs to be done. “We need to learn more on multiple levels. The neuroligin is only one group of genes associated with autism. It is not the whole story,” Scheiffele said. “We need better genetic studies and identification of genetic defects. This highlights how important it is that more funding be made available. I don’t want to give any false hope” about when a cure might be discovered.
Chih plans to expand his research in the future. “I am continuing this study focusing on neuroligin’s role in an animal model,” he said. “Now we are making mutant mice that lack neuroligin protein and see if they would have behavioral defects.”
Autism research is particularly important today. In the last 15 years, there has been an increase in the number of children with autism, and research indicates that one in every 150 children in the United States may be affected.
“It is not completely clear what the cause is or if the numbers are correct, but the numbers are alarming,” Scheiffele said.
The study used primary neurons from the hippocampus of embryonic rats, which enabled Scheiffele’s team of researchers to obtain precisely and directly manipulate the cellular function. Scheiffele and Chih found that rat neurons without neuroligin have altered connections similar to those in children with autism.
“Columbia has a very strong group of researchers studying many different aspects of autism,” Scheiffele said. Besides developmental biologists like Scheiffele, these include researchers who use functional imaging to explore which brain areas are activated when individuals engage in social interactions, and researchers who examine the potential influence of environmental factors, such as viral infections and toxins on neuropsychiatric disorders.
The project received funding from the National Alliance for Austistic Children and the National Institute for Neurological Disorder and Stroke.
http://www.columbiaspectator.com/vnews/d...5780641d9b