Animal models are also used for testing translatable biomarkers, which are measures that can be assessed comparably in both human and animal subjects. These biomarkers serve as tools to examine the efficacy of potential therapeutics in animal models, predict their effect in human subjects and inform clinical trials. A recent study in Molecular Autismidentified dysfunction in the protein metabolism of children in ASD and a selection of disorder biomarkers with potential use in clinical diagnosis.
Why use animal models?
Generation of animal models for ASD relies on findings evolving from genetic and environmental studies, which inform us about the insults responsible for the behavioral deficits. Insults (e.g., genetic mutation) are then mimicked in animals modelling the deficits we observe in sufferers and allowing study of the altered mechanisms at the molecular, cellular, and brain level. For example, these models can address questions about the biological effects of a specific genetic mutation on (1) the strength of interaction between nerve cells (known as synaptic plasticity), (2) the integrity of communication
between brain regions that work together to regulate specific behavior (known as brain circuits) and (3) on cognitive, motor and social behaviors. Answers to these questions provide the platform for future studies focused on drug discovery and development.
For example a study in Molecular Autismin a Rett syndrome mouse model, modelling a X-linked neurodevelopmental disorder caused by mutations in gene transcription regulation, identified disrupted cellular processes, including DNA binding. It also identified novel protein targets, involved in neuron structure and synaptic transmission, with potential in therapeutic development.
Research at the Seaver Autism Center
At the Seaver Autism Center for Research, we are characterizing mouse and rat models with mutations in several ASD risk genes, including in the SHANK3, leading to Phelan McDermid Syndrome (PMS) and the FMR1 gene, leading to Fragile X syndrome. By taking the approach described above, we discovered that treatment with IGF-1 in a mouse model with a mutation in the Shank3 gene ameliorates synaptic plasticity and motor deficits. These findings formed the basis of clinical trials with IGF-1 in individuals with PMS which established the feasibility of IGF-1 treatment in PMS, providing proof of concept to advance knowledge about developing targeted treatments for the synaptic dysfunction associated with ASD.
Another example comes from our recent study on a rat model for ASD, the Shank3-deficient rat, harboring a mutation in the Shank3 gene. These rats exhibit social behavior and attentional deficits, recapitulating the neuropsychiatric features of PMS. The nature of the models deficits led us to test the effect of the pro-social hormone, oxytocin, on the synaptic plasticity and behavioral deficits. We found oxytocin significantly improved social memory, attention, and synaptic plasticity deficits, suggesting that oxytocin may have therapeutic potential for both social and non-social deficits in individuals with PMS, supporting our ongoing clinical trials with oxytocin in these individuals.
The study of stem cells has also gained a lot of attention in autism research. Stem cells can be generated from blood or skin samples and differentiated to nerve cells which are examined in the lab. Stem cells can also be used to study the
molecular and cellular mechanisms affected in each individual with ASD, with the benefit of testing for personalized treatment. A recent study published in Molecular Autismaddressed the issue of a limited understanding of Angelman (AS) and Duplication 15q (Dup15q) syndromes at a molecular level, due to an inability to analyze gene expression in living neurons.
Stem cells are also efficient for carrying out high-throughput screening of small molecules, which can accelerate the discovery of new molecules with potential therapeutic effect. At the Seaver Center, we continue to develop the use of stem cells in autism research, and enroll every affected individual that visits our clinic, his/her parents, and unaffected siblings in this research.
Tune into The Mount Sinai Hospital Facebook on the 5th of June at 11am EST / 3pm GMT to hear myself, Dr. Harony-Nicolas’s, speak in more depth about the topic of animal and cell models used in Autism research at the Seaver Center.
Learn more about the Seaver Autism Center at www.seaverautismcenter.org
Discover more of the current research ongoing in this field at Molecular Autism.