Autism spectrum disorder is a group of social and neurodevelopmental disorders that include difficulty with interpersonal interaction, communication and excessive repetitive behaviors. Currently, though there are medications to treat some symptoms but no drug therapies exist to treat the underlying disorders.
Treating mice with a compound called SR1078 showed reduced autistic behavior in the mouse analog of autism, according to Thomas Burris, Ph.D., chair of pharmacology and physiology at Saint Louis University, by increasing the expression of genes known to be low in the brains of autistic patients.
RORa, a nuclear receptor, tends to be low in the brains of those with autism. An activator of gene expression, RORa has been shown to regulate the key genes that are underexpressed in autistic brains. SR1078, that increases the activity of RORa, and, subsequently, increases expression of the missing genes.
"We developed the first drugs that can target RORa effectively. SR1078 is, at this point, more of compound than a true drug. It will have to be optimized before it is ready for human testing," Burris said. "However, it is able to reach the brain, and that is a key factor."
In the modified mouse that mimics autism, animals display behavior such as overgrooming, fixation on inanimate objects and social deficits.
"Mice groom themselves constantly. We use videotape and count their grooming events. A normal mouse will groom itself around 125 times in 10 minutes. Mice with an autistic profile will groom themselves 250 times in that span due to excessive repetitive behavior."
When these mice were treated with the drug compound, Burris found both increased expression of the missing genes and reduced autistic behavior, with a significant decrease in repetitive grooming events.
Additionally, studies with human brain cells in culture also showed that the drug increases the expression of these genes, as well.
Next, the research team will study the mice's social activity and see what impact the drug has on this aspect of their behavior.
The research is in early stages and much more study will need to be completed, including clinical trials in humans, before it could be used as a therapy for children with autism. However, the research team is encouraged by their progress in a field that currently offers very few pharmacological options for those on the autism spectrum.