DEPARTMENT OF DEFENSE - CONGRESSIONALLY DIRECTED MEDICAL RESEARCH PROGRAMS

Autism-Associated Mutations in L-Type Ca2+ Channels

Principal Investigator: CONTRACTOR, ANIS
Institution Receiving Award: NORTHWESTERN UNIVERSITY, CHICAGO, ILLINOIS
Program: ARP
Proposal Number: AR170057
Award Number: W81XWH-18-1-0777
Funding Mechanism: Idea Development Award - Partnering PI Option
Partnering Awards: AR170057P1
Award Amount: $281,375.75


PUBLIC ABSTRACT

Autism Spectrum Disorders (ASDs) are characterized by problems with social engagement and communication, as well as inappropriate restrictive and repetitive behaviors. It has been reported that as many as 1 in 70 children are diagnosed with autism; therefore, it represents a major health problem that also profoundly impacts a sizeable number of military families. ASDs have a strong genetic heritability component, but only in a small proportion of cases has the genetic basis been identified, and there is large heterogeneity in the genetic causes. Autism spectrum disorders (ASDs) are characterized by problems with social engagement and communication, as well as inappropriate restrictive and repetitive behaviors. It has been reported that as many as 1 in 70 children are diagnosed with autism; therefore, it represents a major health problem that also profoundly impacts a sizeable number of military families. ASDs have a strong genetic heritability component, but only in a small proportion of cases has the genetic basis been identified, and there is large heterogeneity in the genetic causes.

Recently, several mutations were identified in individuals with ASDs in genes that code for important Ca2+ channels. These ion channels are known to affect neuronal and synaptic development and, therefore, are likely causal to autism diagnosed in these patients. More specifically, because these mutations are known to cause a gain-of-function phenotype, increasing Ca2+ influx through the channel, they provide a unique opportunity to model the disorder in a mouse and establish a “molecules to behavior” understanding of how brain circuits are functionally altered in ASDs. The two partnering laboratories have collaborated to create a novel mutant mouse with the human mutation engineered into the genome. The mice display several aberrant repetitive and social behaviors that are correlates of the altered behaviors in the human disorder. Therefore, these mice are potentially valuable models for understanding the alterations in brain activity that underlie ASDs.

In this proposal, we will use these mice to determine the extent of the alteration in synapses, neural circuits, and behavior and ask the following three questions:

1. How does the mutation in this ion channel affect the development of neurons in a region of the brain known to be important for repetitive and restricted behaviors?

2. What are the alterations in naturalistic behaviors in these mice that correlate with the symptoms of ASDs, and can we detect this by imaging activity of neurons as mice perform basic behaviors?

3. Can we fix the problems in these mice by using drugs that target this ion channel?

This proposal directly addresses one of the “Areas of Interest” by assessing novel therapeutics in valid preclinical models. These studies are designed to understand a critical problem in the ASD field, address important knowledge gaps, and ultimately will determine whether we can find ways to rectify the activity in brain circuits that contribute to the altered behaviors in ASDs. Our experimental design will employ cutting-edge techniques to record from neurons in regions of the brain associated with ASDs and is designed to incorporate the complementary expertise of the partnering laboratories. The ultimate outcome will be in identifying the network basis for repetitive and restricted behaviors, which are a hallmark of ASDs, and will inform the future development of novel treatments.