Progetto: New Mouse Models of Friedreich’s Ataxia

Principal Investigator: Dr.Cathleen M Lutz, PhD- Director of Rare and Orphan Disease Center, Director of Mouse Repository – Jackson Laboratory, USA.

Il progetto supporta l’ingegnerizzazione presso il Laboratorio Jackson (JAX)  di due nuovi modelli di atassia di Friedreich (FRDA), un  BAC transgenico con una lunga ripetizione GAA  e un modello  di topo  Knock-in  con ripetizioni GAA nel locus della Fratassina. Il finanziamento ricevuto sarà utilizzato per creare tali modelli sulla base delle osservazioni cliniche di riferimento relative al peso e alla sopravvivenza e con un fenotipo manifesto.

JAX ha collaborato con la comunità FRDA sin dal 2007 importando e standarizzando gli esistenti modelli di topo FRDA.  In uno studio compartivo longitudinale è stato determinato che tutti  i modelli esistenti, pur con vari livelli di espressione della proteina Fratassina,  presentano un fenotipo neurologico (per esempio andatura)  molto subdolo che inizia a manifestarsi solo intorno ai 9-12 mesi di vita dell’animale. Mentre questi modelli sono adatti ad essere usati in studi preclinici atti a testare la sovra –regolazione della espressione del gene della Fratassina  e a misurare la proteina, essi falliscono nel  rilevamento di importanti misure di efficacia neurologica a breve tempo.

Nel Maggio del 2014 GoFAR e FARA  hanno organizzato un meeting a Filadelfia per superare l’esistente ostacolo della carenza di un modello FRDA adeguato a fornire informazioni in tempi brevi relative all’efficacia di eventuali trattamenti atti a curare la FRDA. E’stato deciso che tale ingegnerizzazione sarebbe avvenuta allo JAX per assicurare la rapida caratterizzazione e distribuzione  di questi nuovi modelli FRDA.

Finanziamento: 85.440 $ (Agosto 2014-Luglio 2015) Co-finanziato da FARA

Progetto: Beta-band EMG-EMG coherence: a novel, painless and simple screening test for the onset of corticospinal tract disease/dorsal root ganglionopathy in Friedreich’s Ataxia

Principal-Investigator: Dr Mark R Baker, Institute of Neuroscience, Newcastle University, UK
Co-Investigators: Professor Patrick F Chinnery, Institute of Genetic Medicine and Professor Stuart Baker, Institute of Neuroscience, Newcastle University, UK

Friedreich’s Ataxia (FA) is an autosomal recessive hereditary ataxia with a very high carrier rate (between 1/60 and 1/90), caused by unstable GAA trinucleotide repeat expansions within the first intron of the frataxin (FXN) gene. FXN is clearly important in normal mitochondrial function; reduced levels of functioning FXN results in mitochondrial iron accumulation and the accumulation of multiple mitochondrial DNA deletions.
In patients the lack of functioning FXN typically manifests as a progressive neurological syndrome with features of dorsal root ganglionopathy, and degeneration and atrophy of the dorsal columns, spinocerebellar tracts, corticospinal tracts and dentate nuclei.
With the increasing understanding of the molecular basis of FA and the move to potential neuroprotective therapies, there is an increasing need for non-invasive measures of neuronal degeneration and loss. Such measures must be capable of detecting subclinical pathological changes in individuals with a genetic diagnosis who have not yet developed extensive neuronal loss, thus permitting early intervention.
We propose to develop just such a measure using surface electromyogram (EMG) recorded using a novel handheld device developed in our research laboratory. This test is painless and therefore easy to use in children. It is also extremely simple to perform and could be delivered by any healthcare professional.
We plan a longitudinal study of adult and paediatric patients with FA. Repeated surface EMG recordings will be made at intervals of 3 months, in addition to routine clinical neurophysiological tests, which will include nerve conduction studies (NCS), sensory evoked potentials (SEPs) and transcranial magnetic stimulation (TMS) motor evoked potentials (MEPs). Finally, these electrophysiological measures will be compared with measures of frataxin (FXN) expression and functional assays of frataxin deficiency (i.e. mitochondrial dysfunction and degeneration)
In this project we aim to develop a simple, painless, inexpensive and portable electro-diagnostic screening test of subclinical sensory neuronopathy/corticospinal tract degeneration in Friedreich’s Ataxia and to assess what happens to this electrophysiological measure over time in a longitudinal study and thus to establish whether it can be used as a marker of progression (or surrogate outcome measure) for future therapeutic trials.

Finanziamento: 149,358 $ ( 1anno da 17 Novembre 2014) Co-finanziato da FARA e Ataxia UK

Progetto: Early and longitudinal assessment of neurodegeneration in the brain and spinal cord in Friedreich’s ataxia

Principal Investigators: Pierre-Gilles Henry, Ph.D, Christophe Lenglet, Ph.D – Center for Magnetic Resonance Research, Department of Radiology,University of Minnesota Medical School, Minneapolis US

We propose to assess the sensitivity of candidate biomarkers forFriedreich’s ataxia in patients, using Magnetic Resonance Imaging (MRI) techniques.Sensitive early-stage biomarkers of the disease are currently lacking in Friedreich’s Ataxia (FRDA).Such biomarkers would constitute an invaluable tool for monitoring disease progression in prospective therapeutic trials.In this project, we propose to use both Magnetic Resonance Spectroscopy (MRS) and diffusionMagnetic Resonance Imaging (diffusion MRI). MRS allows non-invasive measurement of a“neurochemical profile” of 10-15 metabolites, and has the potential to reveal biochemical alterations in the nervous system before irreversible tissue damage. Diffusion MRI, in combination with advanced white matter fiber orientation mapping and tractography algorithms, provides unprecedented information about the integrity of the cerebral, cerebellar and spinal axonal wiring.Preliminary data obtained in our center in the past year shows significant differences in both MRS and diffusion MRI data between patients and controls.  In this project based on our preliminary results, we propose to focus on a subset of the data already acquired and investigate year-to-year temporal changes in Friedreich’s ataxia.We hope to identify sensitive biomarkers of the disease in the central nervous system of patients with Friedreich’s ataxia at an early stage, and gain better insights into their temporal evolution. These aims could ultimately provide novel and unique tools for the quantitativeassessment of treatment efficacy in prospective therapeutic trials.

Finanziamento:149,793$ (1anno da 1 Maggio 2014) Co-finanziato da FARA e Ataxia UK

Progetto: Investigation of mitochondrial function and novel therapies in Friedreich’s ataxia mouse models

Principal Investigator: Dr. Paola Giunti, Co-PI Andrey Abramov Department of Molecular Neuroscience Institute of Neurology, UCL, London

We propose to study the mitochondrial pathophysiology in FRDA using mouse models (YG8R and KIKO), and the pharmacological effects of Nrf2 inducers and D-PUFAs compounds on the mitochondrial function in  models, looking at different cell types variably involved in the disease, such as neurons and glia of the cerebellum and kidney fibroblast cells.

The methodologies chosen to achieve our goals include: cell biology, functional microscopy, fluorescence imaging techniques, and oxygen consumption measurements. Experiments will be conducted initially on primary cultures of cerebellar granular cells, co-cultures of neurons and glia, freshly isolated a kidney fibroblast cells. These cell culture preparations are currently used in our lab for other projects. The assays will include pre-clinical studies of two different types of drugs that will tackle potential therapeutic targets to envisage novel pharmaceutical trials for FRDA patients. The first type of compounds are Nrf2 inducers, that will trigger the antioxidant pathway of Nrf2, which has been found to be involved in FRDA (Shan et al,. 2013), and will also provide mitochondrial respiration substrates, helping the mitochondrial bioenergetics (Homstrom et al., 2013; Luthmann et al., 2013). The second type of compounds, D-PUFAs, will protect the cells from lipid peroxidation, which is relevant in FRDA mitochondrial function and, more importantly, our preliminary data has shown that FRDA mouse model cerebellar granule cells undergo dramatic increases in lipid peroxidation.

Finanziamento:133,000$ ( 1anno da 1 Maggio 2014) Co-finanziato da FARA

Progetto:Investigating the mechanisms of long-range epigenetic gene regulation (LREGR) at the Friedreich’s ataxia (FRDA) locus.

Dr Mark Pook-Ataxia Research Group, Division of Biosciences, Brunel University, Uxbridge, UK

Since GAA repeat expansions in the frataxin gene were identified as the genetic cause of Friedreich’s ataxia in 1996, research in the field has rapidly progressed and at the same time our understanding of the complexity of the disease mechanisms has increased. In this context, we have recently shown that GAA repeat expansions, in addition to impairing the expression of the frataxin gene, can also impair the expression of a second gene named PIP5K1B and located near the frataxin gene. Based on these findings, we propose that GAA expansions may act at a distance to impair the expression of several surrounding genes, and this could have important consequences in Friedreich’s ataxia. Now, using cells in culture, we would like to pursue this work by:

1) determining which additional genes located near the frataxin gene are indeed affected,

2) understanding the molecular mechanisms responsible for these effects. This work may lead to the identification of additional target genes and novel mechanisms relevant to Friedreich’s ataxia,which might result in the design of new therapeutic strategies to counteract the disease.

GoFAR has come to award an additional research grant of 5.000 £ to Dr.M. Pook.