Removal of rab11 endosomes affects spines morphology and dendritic arbor development.

SEBASTIAN SIRI; QUASSOLLO GONZALO; REMEDI MONICA; CONDENDE CECILIA

La serena

Congreso; Actualizations in membrane trafficking in health and disease.; 2016

p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 120%; }p.western { font-family: "Calibri",sans-serif; font-size: 11pt; }p.cjk { font-family: "Calibri",sans-serif; font-size: 11pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 11pt; }a:link { color: rgb(0, 0, 255); }A large bodyof experimental data over the last 20 years has demonstrated thecrucial role of endosomal traffic during cell development. Theneuronal dendritic arbor development requires a proper spatiotemporaldistribution of the elements of the secretory and endocytic pathways,as well as a dynamic and regulated communication between them.Accordingly, our work has focused on characterizing the role of therecycling endosome (RE) during the development of the dendritic arborin primary embryonic hippocampal neurons. We first determined theendogenous localization of the RE at different times in culture fromday 1 to 21. In the first 8 hours the RE shows a juxtanucleardistribution. After 24 hours the RE, changes its localization to amore broad distribution throughout the neurites until the day 14where it mainly concentrate on the processes tips.Upon using ashRNA-Rab11 we observed a shift in the RE distribution as well asmorphological changes of the normal development of dendriticarborization. In addition, we observed a shortening of the mainneurite and a concomitant increase in number of dendritic branches.Similarresults were found using dominant negative Rab11 constructs inagreement with the important regulatory role of Rab11 on RE dynamic.We quantified the number and type of dendritic spines on matureneurons: a greater number of filopodia spines-like was observed inneurons treated with the shRab11. These results are in agreement withrecently published results suggesting that endosome positioning isbecoming an important factor in controllingsynapse architecture(Esteves da Silva et al, 2015).Remarkably,suppression of Rab11 resulting a significant decrease in theexpression or association to MAP2, which does not occur with otheradapter proteins microtubule, like MAP1B. Taken together, ourexperimental findings suggest that the recycling endosome Rab11member play a key regulatory role on dendritic arbor development.