Professional Education
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Doctor of Philosophy, University of Toronto (2017)
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Master of Science, Queen's University (2014)
Amyotrophic lateral sclerosis is a fatal disease resulting from motor neuron degeneration in the cortex and spinal cord. Cortical hyperexcitability is a hallmark feature of amyotrophic lateral sclerosis and is accompanied by decreased intracortical inhibition. Using electrophysiological patch-clamp recordings, we revealed parvalbumin interneurons to be hypoactive in the late pre-symptomatic SOD1*G93A mouse model of amyotrophic lateral sclerosis. We discovered that using adeno-associated virus-mediated delivery of chemogenetic technology targeted to increase the activity of the interneurons within layer 5 of the primary motor cortex, we were able to rescue intracortical inhibition and reduce pyramidal neuron hyperexcitability. Increasing the activity of interneurons in the layer 5 of the primary motor cortex was effective in delaying the onset of amyotrophic lateral sclerosis-associated motor deficits, slowing symptom progression, preserving neuronal populations, and increasing the lifespan of SOD1*G93A mice. Taken together, this study provides novel insights into the pathogenesis and treatment of amyotrophic lateral sclerosis.
View details for DOI 10.1093/brain/awaa034
View details for Web of Science ID 000522641900018
View details for PubMedID 32203578
Huntington's disease (HD) is a genetic neurodegenerative disorder of the central nervous system characterized by choreatic movements, behavioral and psychiatric disturbances and cognitive impairments. Deficits in learning and memory are often the first signs of disease onset in both HD patients and mouse models of HD and are in part regulated by the hippocampus. In the R6/2 mouse model of HD, GABAergic transmission can be excitatory in the hippocampus and restoring inhibition can rescue the associated memory deficits. In the present study we determine that hippocampal GABAergic neurotransmission in the R6/2 mouse is disrupted as early as 4 weeks of age and is accompanied by alterations in the expression of key inhibitory proteins. Specifically, spontaneous inhibitory postsynaptic currents were initially increased in frequency at 4 postnatal weeks and subsequently decreased after the mice displayed the typical R6/2 behavioral phenotype at 10 weeks of age. Symptomatic mice also exhibited a change in the probability of GABA release and changes in the basic membrane properties including neuronal excitability and input resistance. These electrophysiological changes in presymptomatic and symptomatic R6/2 mice were further accompanied by alterations in the protein expression level of pre- and postsynaptic inhibitory markers. Taken together, the present findings demonstrate profound alterations in the inhibitory neurotransmission in the hippocampus across the lifespan of the disease, including prior to neuronal degeneration, which suggests that the inhibitory hippocampal synapses may prove useful as a target for future therapeutic design.
View details for DOI 10.1016/j.neuroscience.2019.02.007
View details for PubMedID 30797895
View details for DOI 10.1073/pnas.1716871115
View details for DOI 10.7554/eLife.28270
View details for DOI 10.1074/jbc.M116.767236
View details for DOI 10.1038/ncomms13721
View details for DOI 10.1016/j.molcel.2016.11.033
View details for DOI 10.3389/fncel.2015.00368
View details for DOI 10.1152/jn.00603.2014
View details for DOI 10.1152/jn.00494.2014
View details for DOI 10.1523/JNEUROSCI.5815-12.2013