Reciprocal control of excitatory synapse numbers by Wnt and Wnt inhibitor PRR7 secreted on exosomes

Sang H. Lee, Seung Min Shin, Peng Zhong, Hyun Taek Kim, Dong Il Kim, June Myoung Kim, Won Do Heo, Dae Won Kim, Chang Yeol Yeo, Cheol Hee Kim, Qing song Liu

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Secreted Wnts play crucial roles in synaptogenesis and synapse maintenance, but endogenous factors promoting synapse elimination in central neurons remain unknown. Here we show that proline-rich 7 (PRR7) induces specific removal of excitatory synapses and acts as a Wnt inhibitor. Remarkably, transmembrane protein PRR7 is activity-dependently released by neurons via exosomes. Exosomal PRR7 is uptaken by neurons through membrane fusion and eliminates excitatory synapses in neighboring neurons. Conversely, PRR7 knockdown in sparse neurons greatly increases excitatory synapse numbers in all surrounding neurons. These non-cell autonomous effects of PRR7 are effectively negated by augmentation or blockade of Wnt signaling. PRR7 exerts its effect by blocking the exosomal secretion of Wnts, activation of GSK3β, and promoting proteasomal degradation of PSD proteins. These data uncover a proximity-dependent, reciprocal mechanism for the regulation of excitatory synapse numbers in local neurons and demonstrate the significance of exosomes in inter-neuronal signaling in the vertebrate brain.

Original languageEnglish
Article number3434
JournalNature Communications
Issue number1
StatePublished - 1 Dec 2018

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© 2018, The Author(s).


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