Abstract
Dendritic growth is essential for the establishment of a functional nervous system. Among extrinsic signals that control dendritic development, substantial evidence indicates that BDNF regulates dendritic morphology. However, little is known about the underlying mechanisms by which BDNF controls dendritic growth. In this study, we show that the MAPK signaling pathway and the transcription factor cAMP response element-binding protein (CREB) mediate the effects of BDNF on dendritic length and complexity. However, phosphorylation of CREB alone is not sufficient for the stimulation of dendritic growth by BDNF. Thus, using a mutant form of CREB unable to bind CREB-regulated transcription coactivator (CRTC1), we demonstrate that this effect also requires a functional interaction between CREB and CRTC1. Moreover, inhibition of CRTC1 expression by shRNA-mediated knockdown abolished BDNF-induced dendritic growth of cortical neurons. Interestingly, we found that nuclear translocation of CRTC1 results from activation of NMDA receptors by glutamate, a process that is essential for the effects of BDNF on dendritic development. Together, these data identify a previously unrecognized mechanism by which CREB and the coactivator CRTC1 mediate the effects of BDNF on dendritic growth.
Highlights
Increases in Dendritic Growth by BDNF Require NMDA Receptor-mediated Activation of Calcineurin by Glutamate— we examined whether nuclear translocation of CRTC1 by NMDA receptor-mediated activation of calcineurin contributes to the effects of BDNF on dendritic growth
We have shown that activation of MAPK, cAMP response element-binding protein (CREB), and CRTC1 plays a critical role in mediating the effects of BDNF on dendritic growth
Our data revealed that nuclear translocation of CRTC1 results from NMDA receptor-mediated activation of calcineurin
Summary
Cortical Neuron Culture—All experiments were performed in accordance with the European Communities Council Directive regarding the care and use of animals for experimental procedures. Inhibition of PLC␥1 by U73122 did not affect BDNF-induced increases in dendritic length with CRTC1 shRNA or Ctrl shRNA, and the ratio of CRTC1 and branching (Fig. 1C) These results indicate that activation immunofluorescence intensity in the nucleus of the transfected of the MAPK signaling pathway is required for mediating the neuron to that in neighboring non-transfected neurons was effects of BDNF on cortical dendritic morphology. Tyr204 p44/42 MAPK (1:1000), rabbit anti-phospho-Ser473 Akt sufficient to increase the total dendritic length and branch (1:1000), rabbit anti-phospho-Ser133 CREB (1:1000; Cell Signal- point number of cortical neurons (Fig. 2, A and B), whereas ing Technology), mouse anti-Myc tag (9B11; 1:2000), rabbit transfection of cortical neurons with a constitutively active anti-CRTC1 (C71D11; 1:1500), and mouse anti--tubulin form of PI3K [26] did not enhance the extent and complexity of (clone tub 2.1; 1:1000; Sigma) antibodies.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
