Dr. Jongens and his collaborators have found an insulin-like protein in the fly brain that is overexpressed in the Fragile X mutant fly, leading to increased activity of the insulin signaling pathway. Furthermore, they found that certain behavioral patterns in the fragile X flies can be rescued by expressing the FX gene just in insulin producing neurons in the fly brain. In the mutant, there are other changes in the signaling pathways, including a decrease in cAMP and elevation in PI3K, mTOR, Akt and ERK activity. They now propose to study 2 medicines used for diabetes: pioglitazone (increases cAMP and decreases Akt and ERK) and metformin (inhibits mTOR), in flies and mice to validate the potential efficacy of these novel therapeutics for Fragile X.
With a $90,000 grant from the FRAXA Research Foundation from 2013-2014, Dr. Andres Ozaita led a team to test rimonabant’s ability to blockade the CB1 receptor. Blocking CB1 has shown potential to reverse most symptoms of disease in mice bred to mimic 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 in 2013-2014, Dr. Molly Huntsman’s team examined how these networks interact and how inhibitory deficits can best be remedied.
With a $180,000 grant from the FRAXA Research Foundation over 2011-2014, Dr. Yue Feng and Dr. Wenqi Li at Emory University will study CDK5 pathway function and regulation in an effort to break down whether and how CDK5 signaling is affected by the loss of the fragile X protein, FMRP, in the fragile X mouse model.
With a $90,000 grant from FRAXA Research Foundation over 2013-14, Dr. Marius Wernig and Dr. Samuele Marro at Stanford analyzed homeostatic plasticity and regulation of synaptic strength by retinoic acid. If the results are encouraging, they will move forward with testing whether available RA antagonists can alleviate observed abnormalities in these cells.
Scientists have found increases in the numbers of neurons in brain regions of autistic children, suggesting a problem in developmental programmed cell death pathways. One of the most important effectors of neuronal survival during brain development is the “anti-cell death” protein Bcl-xL. While the normal function of Bcl-xL is to maintain a healthy number of neurons and synapses, over-expressed Bcl-xL can cause an overabundance of synaptic connections. This may be happening in fragile X.
With a 2-year, $90,000 grant from FRAXA Research Foundation, Dr.’s Matthew Disney and Wang-Yong Yang worked to correct the underlying problem in fragile X: the silencing of the fragile X gene (FMR1) and the resulting lack of FMRP (Fragile X Mental Retardation Protein). Their approach was to use novel small molecules to target the abnormal CGG repeats before the FMR1 gene.
One of the features of the fragile X mouse model which is relevant to the human fragile X syndrome (and autism) is social behavior. Several tests show consistent social behavioral abnormalities in the fragile X mouse model. With a $140,000 grant from FRAXA Research Foundation in 2012-2013, Dr. Willemsen at Erasmus University used social behavior tests to measure the effectiveness of several drug strategies.
With a $140,000 grant from FRAXA Research Foundation, Dr. Vitaly Klyachko and team at Washington University explored STP (short-term plasticity) in fragile X, namely looking at presynaptic calcium dynamics as a major underlying cause of the STP defects.
Of the many genes known to be regulated by FMRP, the gamma-aminobutyric acid receptor A (GABA(A)), is gaining attention as a potential target for the treatment of FXS. Mounting evidence suggests decreased expression and functioning of GABA(A) is involved in the pathophysiology of FXS. Non-selective GABA(A) agonism in animal models of FXS has been associated with normalization of morphological features, GABA(A) expression, and behavior. However, the clinical use of these agents in fragile X is associated with unwanted side-effects, such as sedation, dulling of cognition, and occasional paradoxical agitation, which limits their use. Given the limitations in available GABA(A)-based treatment of FXS, this group plans to investigate a novel selective GABA(A) agonist in a mouse model of FXS. This agent has the potential to relieve many symptoms of fragile X without the unwanted side effects.
With a $157,000 grant from the FRAXA Research Foundation in 201202013, Dr. Kendal Broadie and Dr. Cheryl Gatto worked to define the distinct but also overlapping roles for MMP-1 and MMP-2 in synaptic structural and functional development. In drug studies with fragile X fruit flies, they will be testing a range of MMPIs in drug treatments to compare effectiveness during development and at maturity, in order to define the contributions of FXS developmental impairments and adult recovery/plasticity.