The Role Of Lrp4 In The Piriform Cortex

Synaptic plasticity is very important in the central nervous system(CNS),because this process is associated with learning and memory.Synapse dysfunction has been implicated in a series of neuropsychiatric disorders,including schizophrenia,epilepsy,autism and so on.LRP4(or MEGF7)is is a member of the low-density lipoprotein receptor(LDLR)family which is critical for neuromuscular junction(NMJ)formation and maintenance,the role of Lrp4 in the CNS is focus on hippocampus but little about other brain region which Lrp4 also expressed.Lrp4 is a single-pass transmembrane protein contain a large extracellular domain(ECD)which is 90% of the protein.Recently,some studies show that Lrp4 is required for normal hippocampal synaptic plasticity,intracellular domain(ICD)of Lrp4 is required for limb development but not for hippocampal synaptic plasticity.Therefore,we hypothesised that the ECD of Lrp4 can regulate the synaptic plasticity.In our study,we use Golgi staining,behavior analysis,Lac Z staining and immunohistochemistry to study the role of the ECD of Lrp4 in the CNS,especially the piriform cortex.We found the mice only express the ECD of Lrp4(Lrp4-ECD)displayed a phenotype that the body weight and brain mass were significant recuded,the organization of the hippocampus and piriform cortex appeared normal,but the dentritic spine density was increased both two brain regions and the mice show a deficit in olfactory function and limb clasping which is similar to other mouse models of neurological disorders.Our data suggest that a role of the ECD of Lrp4 in synaptic plasticity and olfactory system.