FRAXA is pleased to announce the first of our 2017 Research Grants aimed at finding specific treatments and ultimately a cure for fragile X syndrome. Several of these projects are funded with generous support from our partner organizations: Autism Science Foundation, The Pierce Family Fragile X Foundation, and the Fragile X Research Foundation of Canada.
Auditory Dysfunction in Fragile X Syndrome, Role for the Sound Localization Pathway
This FRAXA research grant will allow Elizabeth McCullagh, PhD and Achim Klug, PhD to investigate whether neural circuits which process sound are altered in fragile X syndrome. There is a specific circuit which allows us to discriminate between competing sound sources, helping us focus on a sound source of interest such as with a conversation partner. This is the aptly named “cocktail party effect”. The team will measure alterations in this circuit in fragile X syndrome. If clear differences are found, they could be used as potential biomarkers for FXS.
Achim Klug, PhD
Neural Markers of Cognitive, Language, and Behavioral Deficits in Children with Fragile X
With this grant, the team will identify and characterize brain-based markers that predict cognitive, language, and behavioral deficits in young children with fragile X syndrome. Using EEG, a low cost, non-invasive technique, they will measure brain activity in response to sensory stimuli, and correlate this with cognitive, language, and behavioral ratings. The brain-based markers can then be used in future fragile X clinical trials as objective measures for targeted outcomes.
Results from this study should facilitate development of targeted drug and behavioral based interventions. While other research groups have used EEG to study subjects with fragile X, this project will work with much younger children at an earlier stage of development.
Carol Wilkinson MD, PhD
MicroRNA Mediated Astroglial GLT1 Dysregulation in Fragile X
Glutamate is the major excitatory neurotransmitter in the brain. Abnormal regulation of glutamate has been implicated in many neuropsychiatric disorders, including autism, schizophrenia, and fragile X syndrome. It is thought that glutamate levels outside of the nerve cells are elevated and causes nerves more “excited” and induces many symptoms in humans with fragile X and also in mice bred to mimic fragile X syndrome.
Much of glutamate metabolism depends on astrocytes, the versatile and abundant cells nestled between all the neurons of the brain. Extracellular glutamate (which floats around in between brain cells) is regulated by one of the most abundant proteins in the brain, the glutamate transporter GLT1, which is expressed mainly by astrocytes. Previous studies from the Yang lab at Tufts University School of Medicine have found that there is a decrease of this critical glutamate transporter GLT1 in fragile X mice.
This group has shown that removing the fragile X protein from astrocytes decreases the astrocytes’ ability to sweep up excess glutamate. They have recently identified a few small RNA molecules called microRNA that are involved in the regulation of GLT1. With the help of this research grant, they are now exploring how these microRNAs changes underlie decreased GLT1 expression. The Yang lab is also testing whether these microRNAs can restore astrocytes’ ability to reduce extracellular glutamate levels, thus hold the potential to become new therapies for fragile X syndrome.
Haruki Higashimori, PhD
Yuqin Men, PhD
Aberrant Insulin Signaling in a Mouse Model of Fragile X
Insulin signaling is known to be dysregulated in diabetes and cancer, and has lately been described to be implicated in cognitive dysfunctions in neurodegenerative disorders such as Alzheimer’s disease. Furthermore, dysregulation of insulin signaling might also be associated with autism. Funded by FXRFC and FRAXA research grants, this study will systematically investigate the impact of insulin signaling on autistic-like behaviors, synaptic plasticity, spine morphology and mRNA translation in the mouse model of fragile X syndrome.
Ilse Gantois, PhD