The striatum plays a key role in motor activity/coordination and goal-directed, habitual learning. Normal striatal drive of motor activity requires precisely balanced opposing outputs from two types of striatal medium spiny neurons (MSNs) that express D1- and D2-dopamine(DA) receptors. A complex signaling cross-talk between glutamate and DA in D1- and D2-MSNs involves """"""""on demand"""""""" Ca2+-dependent endocannabinoid (eCB) synthesis. Thus, DA, glutamate and eCBs collaborate to balance short- and long-term control of the two striatal output pathways by engaging distinct signaling mechanisms in the two MSN subtypes. Disruption of these mechanisms can induce motor deficits (e.g., Parkinson's Disease) or other abnormal striatal-based behaviors. Ca2+/calmodulin-dependent protein kinase II (CaMKII) has diverse bidirectional roles controlling excitatory synapses in hippocampus, cortex and cerebellum. While CaMKII is expressed in both striatal MSN subtypes, suggesting that it regulates excitatory inputs to striatal MSNs and motor activity, the precise functions of striatal CaMKII are poorly understood. Our analyses of knockin mutant mice with the Thr286 autophosphorylation site in CaMKII? replaced by Ala (T286A-KI mice) revealed specific roles for CaMKII in long- and short term eCB- dependent control of excitatory inputs to D1- and D2-MSNs. We also found that CaMKII? associates with and phosphorylates diacylglycerol lipase ? (DGL?), the rate-limiting enzyme for Ca2+-dependent synthesis of the most abundant brain eCB, 2-arachidonyl glycerol (2-AG). In addition, baseline hyperactivity of T286A-KI mice can be rescued by inhibiting 2-AG breakdown. These initial findings strongly support a novel hypothesis that CaMKII is a critical link between postsynaptic Ca2+ and the initiation of 2-AG signaling that controls striatal synapses and striatal based-behaviors. We also created novel transgenic eAC3I mice that selectively express a short CaMKII inhibitor peptide fused to eGFP in striatal MSNs.
Three specific aims will exploit unique features of T286A-KI and eAC3I mice to test specific hypotheses about the roles of striatal CaMKII autophosphorylation and activity. 1. Test the hypothesis that Ca2+-dependent 2-AG synthesis is modulated by CaMKII. We will identify sites of phosphorylation and CaMKII-binding domains in DGL?. DGL? phosphorylation, DGL? activity and 2-AG synthesis will be investigated in heterologous cells and in striatal slices from WT, T286A-KI and eAC3I mice. 2. Test the hypothesis that CaMKII modulates eCB-dependent synaptic regulation in striatal MSNs. Short and long-term roles of CaMKII will be determined by comparing the properties of excitatory synaptic inputs to D1- and D2-MSNs in striatal slices from WT, T286A-KI and eAC3I mice, and by using CaMKII inhibitor peptides. 3. Test the hypothesis that CaMKII modulates eCB-dependent motor activity. We will evaluate motor activity and coordination under basal conditions and following pharmacological modulation of 2-AG metabolism in WT, T286A-KI and eAC3I mice.

Public Health Relevance

Normal movement and coordination is dependent on a brain region called the striatum, and damage to the striatum gives rise to movement disorders such as Parkinson's Disease, Huntington's Disease and several forms of ataxia. The principle neuronal cells in striatum (medium spiny neurons) integrate input signals from motor cortex and thalamus to provide precisely balanced output to other brain regions that control motor activity. This project investigates molecular mechanisms that control the strength of these input signals, with the goal of identifying novel therapeutic targets to treat movement disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS078291-02
Application #
8536971
Study Section
Synapses, Cytoskeleton and Trafficking Study Section (SYN)
Program Officer
Sutherland, Margaret L
Project Start
2012-09-01
Project End
2017-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
2
Fiscal Year
2013
Total Cost
$334,140
Indirect Cost
$117,305
Name
Vanderbilt University Medical Center
Department
Physiology
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Carlson, Gerald M; Dienel, Gerald A; Colbran, Roger J (2018) Introduction to the Thematic Minireview Series: Brain glycogen metabolism. J Biol Chem 293:7087-7088
Shonesy, Brian C; Parrish, Walker P; Haddad, Hala K et al. (2018) Role of Striatal Direct Pathway 2-Arachidonoylglycerol Signaling in Sociability and Repetitive Behavior. Biol Psychiatry 84:304-315
Marks, Christian R; Shonesy, Brian C; Wang, Xiaohan et al. (2018) Activated CaMKII? Binds to the mGlu5 Metabotropic Glutamate Receptor and Modulates Calcium Mobilization. Mol Pharmacol 94:1352-1362
Bermingham, Daniel P; Hardaway, J Andrew; Refai, Osama et al. (2017) The Atypical MAP Kinase SWIP-13/ERK8 Regulates Dopamine Transporters through a Rho-Dependent Mechanism. J Neurosci 37:9288-9304
Wang, Xiaohan; Marks, Christian R; Perfitt, Tyler L et al. (2017) A novel mechanism for Ca2+/calmodulin-dependent protein kinase II targeting to L-type Ca2+ channels that initiates long-range signaling to the nucleus. J Biol Chem 292:17324-17336
Bluett, Rebecca J; Báldi, Rita; Haymer, Andre et al. (2017) Endocannabinoid signalling modulates susceptibility to traumatic stress exposure. Nat Commun 8:14782
Stephenson, Jason R; Wang, Xiaohan; Perfitt, Tyler L et al. (2017) A Novel Human CAMK2A Mutation Disrupts Dendritic Morphology and Synaptic Transmission, and Causes ASD-Related Behaviors. J Neurosci 37:2216-2233
Wang, Shiyi; Stanika, Ruslan I; Wang, Xiaohan et al. (2017) Densin-180 Controls the Trafficking and Signaling of L-Type Voltage-Gated Cav1.2 Ca2+ Channels at Excitatory Synapses. J Neurosci 37:4679-4691
Patel, Sachin; Shonesy, Brian C; Bluett, Rebecca J et al. (2016) The Anxiolytic Actions of 2-Arachidonoylglycerol: Converging Evidence From Two Recent Genetic Endocannabinoid Deficiency Models. Biol Psychiatry 79:e78-e79
Shonesy, Brian C; Winder, Danny G; Patel, Sachin et al. (2015) The initiation of synaptic 2-AG mobilization requires both an increased supply of diacylglycerol precursor and increased postsynaptic calcium. Neuropharmacology 91:57-62

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