Abstract
Fragile X syndrome, the most commonly known genetic cause of autism, is due to loss of the fragile X mental retardation protein, which regulates signal transduction at metabotropic glutamate receptor-5 in the brain. Fragile X mental retardation protein deletion in mice enhances metabotropic glutamate receptor-5-dependent long-term depression in the hippocampus and cerebellum. Here we show that a distinct type of metabotropic glutamate receptor-5-dependent long-term depression at excitatory synapses of the ventral striatum and prefrontal cortex, which is mediated by the endocannabinoid 2-arachidonoyl-sn-glycerol, is absent in fragile X mental retardation protein-null mice. In these mutants, the macromolecular complex that links metabotropic glutamate receptor-5 to the 2-arachidonoyl-sn-glycerol-producing enzyme, diacylglycerol lipase-alpha (endocannabinoid signalosome), is disrupted and metabotropic glutamate receptor-5-dependent 2-arachidonoyl-sn-glycerol formation is compromised. These changes are accompanied by impaired endocannabinoid-dependent long-term depression. Pharmacological enhancement of 2-arachidonoyl-sn-glycerol signalling normalizes this synaptic defect and corrects behavioural abnormalities in fragile X mental retardation protein-deficient mice. The results identify the endocannabinoid signalosome as a molecular substrate for fragile X syndrome, which might be targeted by therapy.
Original language | English |
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Number of pages | 11 |
Journal | Nature Communications |
Volume | 3 |
DOIs | |
Publication status | Published - 25 Sept 2012 |
Keywords
- METABOTROPIC GLUTAMATE RECEPTORS
- DIACYLGLYCEROL-LIPASE-ALPHA
- MENTAL-RETARDATION PROTEIN
- LONG-TERM DEPRESSION
- NUCLEUS-ACCUMBENS
- SYNAPTIC PLASTICITY
- MONOGLYCERIDE LIPASE
- MESSENGER-RNAS
- CB1 RECEPTOR
- TRANSLATION