title: SNAP-29-mediated modulation of synaptic transmission in cultured hippocampal neurons.
abstract: 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.
authors.affiliation: Department of Neurobiology, Shanghai Second Medical University, 280 Chong Qing Nan Road, 200025 Shanghai, China.
authors.forename: Ping-Yue
authors.initials: PY
authors.lastname: Pan
authors.forename: Qian
authors.initials: Q
authors.lastname: Cai
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Pei-Hua
authors.initials: PH
authors.lastname: Lu
authors.forename: Shumin
authors.initials: S
authors.lastname: Duan
authors.forename: Zu-Hang
authors.initials: ZH
authors.lastname: Sheng
mesh_terms: 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*
chemical_list: 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