Local translation mechanisms to control inhibitory synaptic plasticity

Project Summary Synaptic inhibition in the brain is mostly mediated by GABAergic inhibitory synapses, which are essential in controlling neuronal firing, neuron and circuit excitability, and synaptic plasticity. Inhibitory synapses undergo multiple modes of plasticity but the molecular mechanisms that drive persistent inhibitory post-synaptic plasticity remain poorly defined. As translation of synaptic proteins is essential for many forms of plasticity, synthesis of new inhibitory post-synaptic proteins likely plays a key role in sustaining changes in inhibitory synaptic strength. However, little is known about which inhibitory synaptic proteins are translated, where they are produced and how this process is regulated during activity. Our preliminary work suggests that multiple inhibitory synaptic proteins are locally translated in neuronal dendrites during inhibitory long-term potentiation. This process is tightly regulated by miRNAs, potent negative-regulators of translation. This proposal will examine the control of inhibitory synaptic plasticity by local miRNA-dependent translational regulation, using in vivo and in vitro advanced imaging and electrophysiological approaches. The proposed studies are significant as they have the potential to reveal key mechanisms that drive persistent and long-lasting changes in synaptic inhibition. Given the important roles of inhibitory synapses in the brain, this project will provide crucial insight into the underlying mechanisms of learning, memory and cognition.