The Journal of Neuroscience, March 19, 2008, 28(12):3159-3169; doi:10.1523/JNEUROSCI.5227-07.2008
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Cellular/Molecular
Deafferentation-Induced Activation of NFAT (Nuclear Factor of Activated T-Cells) in Cochlear Nucleus Neurons during a Developmental Critical Period: A Role for NFATc4-Dependent Apoptosis in the CNS
Jessie I. Luoma and
Lance Zirpel
Graduate Program in Neuroscience, Department of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota 55455
Correspondence should be addressed to Lance Zirpel, Department of Neuroscience, University of Minnesota Medical School, 6-145 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455. Email: zirpe001{at}umn.edu
During the development and maturation of sensory neurons, afferent activity is required for normal maintenance. There exists a developmental window of time when auditory neurons, including neurons of the anteroventral cochlear nucleus (AVCN), depend on afferent input for survival. This period of time is often referred to as a critical period. The cellular and molecular mechanisms that underlie AVCN neuron susceptibility to deafferentation-induced death remain unknown. Here, we show that only during this critical period deafferentation of mouse AVCN neurons by in vivo cochlea removal results in rapid nuclear translocation and activation of the transcription factor NFATc4 (nuclear factor of activated T-cells isoform 4). NFAT activation is abolished by in vivo treatment with the calcineurin inhibitor FK506 and the specific NFAT-inhibitor 11R-VIVIT. Inhibition of NFAT significantly attenuates deafferentation-induced apoptosis of AVCN neurons and abolishes NFAT-mediated expression of FasL, an initiator of apoptotic pathways, in the cochlear nucleus. These data suggest that NFAT-mediated gene expression plays a role in deafferentation-induced apoptosis of cochlear nucleus neurons during a developmental critical period.
Key words: auditory; activity-dependent; FasL; AVCN; calcineurin; mouse
Received April 26, 2007;
revised Jan. 10, 2008;
accepted Feb. 7, 2008.
Correspondence should be addressed to Lance Zirpel, Department of Neuroscience, University of Minnesota Medical School, 6-145 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455. Email: zirpe001{at}umn.edu