Distinct effects on the dendritic arbor occur by microbead versus bath administration of brain-derived neurotrophic factor
Proper communication among neurons depends on an appropriately formed dendritic arbor, and thus, aberrant changes to the arbor are implicated in many pathologies, ranging from cognitive disorders to neurodegenerative diseases. Due to the importance of dendritic shape to neuronal network function, the morphology of dendrites is tightly controlled and is influenced by both intrinsic and extrinsic factors. In this work, we examine how brain-derived neurotrophic factor (BDNF), one of the most well-studied extrinsic regulators of dendritic branching, affects the arbor when it is applied locally via microbeads to cultures of hippocampal neurons. We found that local application of BDNF increases both proximal and distal branching in a time-dependent manner and that local BDNF application attenuates pruning of dendrites that occurs with neuronal maturation. Additionally, we examined whether cytosolic PSD-95 interactor (cypin), an intrinsic regulator of dendritic branching, plays a role in these changes and found strong evidence for the involvement of cypin in BDNF-promoted increases in dendrites after 24 but not 48 h of application. This current study extends our previous work in which we found that bath application of BDNF for 72 h, but not shorter times, increases proximal dendrite branching and that this increase occurs through transcriptional regulation of cypin. Moreover, this current work illustrates how dendritic branching is regulated differently by the same growth factor depending on its spatial localization, suggesting a novel pathway for modulation of dendritic branching locally.
KeywordsHippocampal neurons Dendrite arborization BDNF Cytosolic PSD-95 interactor (cypin) Sholl analysis Local stimulation
This work is funded in part by National Science Foundation grants IOS-0919747 and IOS-1353724 (to BLF). KMO is supported by the National Institutes of Health under the Ruth L. Kirschstein National Research Service Award 5 T32 GM008339 from the NIGMS, a Predoctoral Fellowship from the New Jersey Commission on Brain Injury Research #CBIR13FEL002, and a Predoctoral GAANN Fellowship #P200A150131 from the DOE. KED was awarded Aresty Research Funding from Rutgers University. The authors would also like to thank Dr. Kelvin Kwan (Rutgers University) for his generous help with imaging of the microbeads.
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Conflict of interest
The authors declare that they have no conflicts of interest.
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