Main research results
Autism affects about 2% of children in the United States, and about 30% of these children have seizures. Recent large-scale genetic studies have revealed that genetic variations in the sodium channel, known as the Nav1.2 voltage-controlled sodium channel, are the leading cause of autism. Overactive sodium channels in neurons cause seizures. Doctors usually treat seizures by giving the patient medication to close the sodium channels, reducing sodium flow through the axons. For many patients, such treatments work, but in some cases — up to 20 or 30% — treatments don’t work. These children had “loss of function” variants in Nav1.2, which are thought to reduce sodium channel activity in the form of “anticonvulsants.” Therefore, how Nav1.2 sodium channel deficiency leads to seizures is a great mystery in the field that baffles doctors and scientists.
Yang Yang, assistant professor of pharmaceutical chemistry and molecular pharmacology at Purdue University, and his team, including the paper’s first author, postdoctoral researcher Jingliang Zhang, tackled this problem. . They found that in neurons lacking Nav1.2, the expression of multiple potassium channels was surprisingly reduced. Nav1.2 deficiency itself does not cause seizures; The problem arises when potassium channels overcompensate for the lack of sodium channels by shutting down too many potassium channels, causing neurons to become overstimulated, causing seizures. In such cases, sodium channel treatment is clearly ineffective. Yang and his team suggest that developing drugs to open potassium channels would help control seizures in these patients. Notably, researchers from the University of California, San Francisco led by Kevin Bender’s research group made a similar observation independently. Yang and Bender’s articles were published side by side in the same issue. Mobile reporting.
“We’re looking at genetic makeup, so doctors can prescribe a drug and gene therapy based on the genes that have been identified – personalized drugs,” said Yang. “Our study points towards a future research direction, possibly future treatments. We are peacetime warriors, battling humanity’s greatest enemy: disease. There are children who die from these conditions. Our goal is to help them, to help their parents and their families. This kind of basic research is an important part of finding new drugs.”
Prof. Purdue’s expertise
Yang is an expert in the pharmacokinetics, specifically the genetics of chronic pain, epilepsy and autism.
Name of the magazine
Mobile press. The paper is available online.
Expense
This work was supported by the Showalter Research Trust and Purdue Big Idea Challenge 2.0 on Autism (for YY). The research reported in this publication was also supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health (R01NS117585 and R01NS123154 through YY). The authors sincerely thank the support from FamilySCN2A Support the funding of the Potential Action Foundation and the Purdue Institute for Drug Discovery and the Purdue Institute of Integrative Neuroscience for additional funding support. This project was supported in part by the Indiana Brain and Spinal Injury Research Foundation and CTSI Indiana, and partially funded by UL1TR002529 from the NIH. Yang Laboratories appreciates the bioinformatics support from the Collaborative Core for Cancer Bioinformatics (C3B) of the IU Simon Comprehensive Cancer Center (P30CA082709), PCCR (P30CA023168), and the Walther Cancer Foundation.
Brief summary of methods
The team created a unique Scn2a-deficient mouse model, with low levels of the Nav1.2 sodium channel, to understand how lack of a Nav1.2 channel might lead to seizures. They then closely examined the behavior of the sodium and potassium channels and looked at neuronal excitability. When working with the mice, they carefully included a balanced sex ratio to avoid bias in the data.
Contact author and media: Brittany Steff, bsteff@purdue.edu
Source: Yangyang, yangyang@purdue.edu
