SNAP-29-mediated modulation of synaptic transmission in cultured hippocampal neurons.
Identifying the molecules that regulate both the recycling of synaptic vesicles and the SNARE components required for fusion is critical for elucidating the molecular mechanisms underlying synaptic plasticity. SNAP-29 was initially isolated as a syntaxin-binding and ubiquitously expressed protein. Previous studies have suggested that SNAP-29 inhibits SNARE complex disassembly, thereby reducing synaptic transmission in cultured superior cervical ganglion neurons in an activity-dependent manner. However, the role of SNAP-29 in regulating synaptic vesicle recycling and short-term plasticity in the central nervous system remains unclear. In the present study, we examined the effect of SNAP-29 on synaptic transmission in cultured hippocampal neurons by dual patch clamp whole-cell recording, FM dye imaging, and immunocytochemistry. Our results demonstrated that exogenous expression of SNAP-29 in presynaptic neurons significantly decreased the efficiency of synaptic transmission after repetitive firing within a few minutes under low and moderate frequency stimulations (0.1 and 1 Hz). In contrast, SNAP-29 did not affect the density of synapses and basal synaptic transmission. Whereas neurotransmitter release was unaffected during intensive stimulation, recovery after synaptic depression was impaired by SNAP-29. Furthermore, knockdown of SNAP-29 expression in neurons by small interfering RNA increased the efficiency of synaptic transmission during repetitive firing. These findings suggest that SNAP-29 acts as a negative modulator for neurotransmitter release, probably by slowing recycling of the SNARE-based fusion machinery and synaptic vesicle turnover.
Pan
Ping-Yue
PY
Department of Neurobiology, Shanghai Second Medical University, 280 Chong Qing Nan Road, 200025 Shanghai, China.
Cai
Qian
Q
Lin
Lin
L
Lu
Pei-Hua
PH
Duan
Shumin
S
Sheng
Zu-Hang
ZH
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D005456:Fluorescent Dyes; D015870:Gene Expression; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011726:Pyridinium Compounds; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D000644:Quaternary Ammonium Compounds; D034741:RNA, Small Interfering; D051381:Rats; D017207:Rats, Sprague-Dawley; D050600:SNARE Proteins; D009435:Synaptic Transmission / Q000502:physiology*; D013572:Synaptic Vesicles / Q000502:physiology; D033921:Vesicular Transport Proteins / Q000235:genetics* / Q000378:metabolism*
C092350:FM 4-64; D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D000644:Quaternary Ammonium Compounds; D034741:RNA, Small Interfering; C432420:SNAP29 protein, human; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins