Synaptic Remodeling Depends on Signaling between Serotonin Receptors and the Extracellular Matrix

Publication date: 30 May 2017
Source:Cell Reports, Volume 19, Issue 9
Author(s): Monika Bijata, Josephine Labus, Daria Guseva, Michał Stawarski, Malte Butzlaff, Joanna Dzwonek, Jenny Schneeberg, Katrin Böhm, Piotr Michaluk, Dmitri A. Rusakov, Alexander Dityatev, Grzegorz Wilczyński, Jakub Wlodarczyk, Evgeni Ponimaskin
Rewiring of synaptic circuitry pertinent to memory formation has been associated with morphological changes in dendritic spines and with extracellular matrix (ECM) remodeling. Here, we mechanistically link these processes by uncovering a signaling pathway involving the serotonin 5-HT7 receptor (5-HT7R), matrix metalloproteinase 9 (MMP-9), the hyaluronan receptor CD44, and the small GTPase Cdc42. We highlight a physical interaction between 5-HT7R and CD44 (identified as an MMP-9 substrate in neurons) and find that 5-HT7R stimulation increases local MMP-9 activity, triggering dendritic spine remodeling, synaptic pruning, and impairment of long-term potentiation (LTP). The underlying molecular machinery involves 5-HT7R-mediated activation of MMP-9, which leads to CD44 cleavage followed by Cdc42 activation. One important physiological consequence of this interaction includes an increase in neuronal outgrowth and elongation of dendritic spines, which might have a positive effect on complex neuronal processes (e.g., reversal learning and neuronal regeneration).

Graphical abstract

Teaser

Bijata et al. examine a signaling module involving the 5-HT7 receptor (5-HT7R), matrix metalloproteinase 9 (MMP-9), the hyaluronan receptor CD44, and the small GTPase Cdc42. Stimulation of 5-HT7R results in MMP-9 activation, which, in turn, cleaves CD44. This results in local detachment from the ECM, thus facilitating spine elongation via 5-HT7R/Cdc42 signaling.


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