Rab3A is required for brain-derived neurotrophic factor-induced synaptic plasticity: transcriptional analysis at the population and single-cell levels.
Brain-derived neurotrophic factor (BDNF) modulates synaptic strength in hippocampal neurons, in addition to promoting survival and differentiation. To identify genes involved in trophic regulation of synaptic plasticity, we have used a multidisciplinary approach of differential display and family-specific slot blots in combination with whole-cell patch-clamp recordings of dissociated hippocampal neurons. Three hour exposure to BDNF elicited a 2.6-fold increase in synaptic charge and a concomitant induction of 11 genes as revealed by differential display, including the small GTP-binding vesicular trafficking protein Rab3A and the enzyme guanylate cyclase (GC). Slot blot analysis on a population of neurons confirmed an average of 3.1-fold induction of these clones. In contrast, individual pyramidal-like neurons that were first characterized electrophysiologically in the presence of BDNF and subjected to transcriptional analysis displayed more robust increases (4.8-fold), emphasizing the neuronal heterogeneity. Transcriptional changes of Rab3A and GC were accompanied by translational regulation, shown by Western blot analysis. Furthermore, a number of GC-associated and Rab3A effector molecules were induced by BDNF at either the gene or protein levels. The functional role of Rab3A in BDNF-induced synaptic plasticity was assessed using cells derived from Rab3A knock-out mice. These neurons failed to show an increase in synaptic charge in response to BDNF at 10 min; however a late response to BDNF was detected at 20 min. This late response was similar in time course to that induced by postsynaptic activation of glutamate receptors. Our results demonstrate a requirement for Rab3A and may reveal a temporal distinction between presynaptic and postsynaptic mechanisms of BDNF-induced synaptic plasticity associated with learning and memory.
Thakker-Varia
S
S
Department of Neuroscience and Cell Biology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-5635, USA.
Alder
J
J
Crozier
R A
RA
Plummer
M R
MR
Black
I B
IB
D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism* / Q000494:pharmacology; D002478:Cells, Cultured; D002999:Clone Cells / Q000166:cytology / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D018698:Glutamic Acid / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism; D006624:Hippocampus / Q000166:cytology / Q000196:embryology; D051379:Mice; D018345:Mice, Knockout; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011930:Reaction Time / Q000187:drug effects / Q000235:genetics; D017470:Receptors, Glutamate / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism*; D014158:Transcription, Genetic; D020826:rab3A GTP-Binding Protein / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D017470:Receptors, Glutamate; D018698:Glutamic Acid; D020826:rab3A GTP-Binding Protein; D006162:Guanylate Cyclase