Inherited Channelopathies in Cortical Circuits of Fmr1 KO Mice

Andreas Frick, PhD

With this two year award of $90,000, Dr. Zhang and Principal Investigator Dr. Andreas Frick at Neurocentre Magendie in France investigated channelopathies using Fragile X mice. Many other proteins are misregulated as a result of the absence of FMRP. It is known that many ion channels, the pores in the cell membrane which allow neurons to conduct electrical impulses, have altered levels in Fragile X. This state is sometime called a “channelopathy” in the pharma world. This group is studying the effect of specific alterations in ion channels, and potential therapeutic effects of drugs which open and close these channels.

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Compound that Inhibits mGluR5 Corrects Signs of Fragile X in Adult Mice

A study finds that a new compound reverses many of the major symptoms associated with Fragile X syndrome (FXS). The paper is published in the April 12 issue of the journal Neuron, describing the exciting observation that the FXS correction can occur in adult mice, after the symptoms of the condition have already been established. Previous research has suggested that inhibition of mGlu5, a subtype of receptor for the excitatory neurotransmitter glutamate, may ameliorate many of the major symptoms of the disease. This study, a collaboration between a group at Roche in Switzerland, led by Dr. Lothar Lindemann, and Dr. Mark Bear’s MIT lab, used an mGlu5 inhibitor called CTEP to examine whether inhibition of mGlu5 could reverse FXS symptoms.

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GABAergic Inhibitory Function in Fragile X Syndrome

With a $100,000 grant from FRAXA Research Foundation, Drs. Joshua Corbin and Molly Huntsman from the Children’s National Medical Center examined the role of a particular class of brain cells (inhibitory interneurons) that dampen excessive activity in the “emotional center of the brain” (the amydala). This inhibition is deficient in Fragile X, and so they are looking for ways to remedy this. This is particularly interesting to parents of children who are overly anxious and emotional. They worked with Dr. Walter Kaufmann, a clinician at Kennedy Krieger Institute in Maryland.

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Electrophysiological, Biochemical and Immunohistochemical Characterization of Kv3.1 in Auditory Brainstem Nuclei in the Fragile X Knockout Mouse

Leonard Kaczmarek, PhD

With $80,000 in funding from FRAXA over several years, the Yale University team of Leonard Kaczmarek, PhD showed that loss of FMRP leads to an increased Kv3.1 potassium currents. This change impairs timing of action potentials in auditory neurons (and likely others throughout the brain).

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