Fragile X Clinical Trial of New PDE4D Inhibitor from Tetra

With a $200,043 grant from FRAXA Research Foundation, Dr. Elizabeth Berry-Kravis completed a successful Phase 2 clinical trial of a PDE4 inhibitor for adult men with Fragile X syndrome. This trial treated 30 males, 18-45 years of age with a new PDE4D allosteric inhibitor from Tetra Discovery Partners using a crossover design, so that everyone got active drug for part of the time and placebo for part of the time.

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Cellular-Specific Therapeutic Targeting of Inhibitory Circuits in Fragile X Syndrome

Studies have shown that the function of inhibitory networks is disturbed in Fragile X. This abnormality is not well understood but appears to be secondary to abnormalities in metabotropic glutamate and endocannabinoid systems. With a $90,000 grant from FRAXA, Dr. Molly Huntsman’s team examined how these networks interact and how inhibitory deficits can best be remedied.

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Beneath the Surface of Fragile X Syndrome: Study Sheds Light on What’s Happening in Nerve Cells

This FRAXA-funded project has turned up some surprising results. At first, it might seem Kurosaki and Maquat have found yet another cellular process which is malfunctioning in Fragile X. But this finding is intimately related to previous findings of abnormal protein synthesis and misregulated transcription in Fragile X. FMRP (the protein lacking in Fragile X syndrome) is involved in chaperoning messenger RNAs within cells to active sites, and in controlling their translation into many different proteins. Some of these proteins are transcription factors, which feed back to the nucleus to control gene expression.

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Auditory Dysfunction in Fragile X Syndrome in a Mouse Model of Fragile X

Elizabeth MCullough and Achim Klug

With a $90,000 grant from FRAXA, Dr. McCullagh and Dr. Achem Klug at the University of Colorado investigated whether auditory neural circuits are altered in Fragile X mice. They saw minor differences in these mice compared to B6 (control) mice in several measures of auditory acuity. Fmr1 mice had increased latency to the startle response for almost all conditions compared to B6 mice, suggesting altered timing to acoustic cues. These experiments show that, consistent with patient reports and anatomical/physiological data, the auditory system is altered in a mouse model of FXS, though with some potential compensation leading to a subtle behavioral impact.

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Reintroducing FMRP via Tat to Reduce Symptoms of Fragile X Syndrome

Ray Turner, PhD and Xiaoqin Zhan, PhD

FRAXA Research Foundation and the Fragile X Research Foundation of Canada have awarded a grant of $100,000 over two years to Dr. Raymond Turner at the University of Calgary in Alberta, Canada. Dr. Turner and postdoctoral fellow Xiaoqin Zhan, PhD are attempting to reactivate a segment of FMRP to reverse symptoms of Fragile X in a mouse model of the disease to reduce abnormal behaviors.

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Retinoic Acid Signaling is Blocked by Fragile X Mutation

Human Neurons

With a 2013-2014 FRAXA Research Grant, Principal Investigator Marius Wernig, PhD and FRAXA Fellow Samuele Marro, PhD at Stanford University found that the Fragile X mutation impairs homeostatic plasticity in human neurons, by blocking synaptic retinoic acid signaling. Retinoic acid is a metabolite of Vitamin A. The system they have developed could provide a powerful new cellular biomarker for screening many treatment approaches.

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Repurposing Study II: Evaluating Combinations of Drugs to Treat Fragile X

Healx team 2018

FRAXA Research Foundation initially partnered with Healx in 2016 to identify existing drugs with potential to treat Fragile X syndrome, using machine learning algorithms and computational biology.  The study produced results, and now FRAXA and Healx have launched a new round of studies to evaluate combinations of compounds, including both drugs and natural products.

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Defining Subcellular Specificity of Metabotropic Glutamate Receptor (mGluR5) Antagonists

Karen O'Malley

With $217,500 in grants from FRAXA Research Foundation, Dr. Karen O’Malley and team studied the function of mGluR5 when it is inside cells. Many of the symptoms of Fragile X Syndrome (FXS) are thought to arise due to overactive metabotropic glutamate receptor 5 (mGluR5) signaling, which is normally opposed by the protein missing in FXS, Fragile X Protein (FMRP).

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Mechanisms of Tolerance to Chronic mGluR5 Inhibition

Over the past few years, both Novartis and Roche sponsored large-scale clinical trials of metabotropic glutamate receptor 5 (mGlu5) negative allosteric modulators (NAMs) to treat Fragile X syndrome (FXS). With a $90,000 grant from FRAXA Research Foundation in 2015-2017, Dr. Mark Bear’s team will explore if mGlu5 NAMs dosed chronically causes tolerance, and if so, how it develops and to probe new avenues to prevent or circumvent it.

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Clinical Trial of Ganaxolone in Patients with Fragile X Syndrome

Frank Kooy, PhD, at University of Antwerp

With a $90,000 grant from FRAXA Research Foundation funded during 2014-2015, Dr. Frank Kooy and colleagues at the University of Antwerp are conducting a double blind crossover trial of ganaxolone in patients with Fragile X syndrome. Results of this study were mixed (see Marinus: Results from Phase 2 Exploratory Clinical Study Support Continued Development of Ganaxolone in Fragile X Syndrome.)

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