Neuropeptides are packaged in dense-core vesicles (DCVs) and released to control development, mood and behavior. Despite the importance of neuropeptides, there is only rudimentary knowledge of how DCVs are delivered to nerve terminals and undergo release in response to bursts of activity. Furthermore, it remains unclear how presynaptic signaling controls exocytosis of DCVs and small synaptic vesicles (SSVs), which contain classical transmitters. This proposal will continue to use GFP-based imaging of DCVs, Ca2+ and presynaptic regulatory and scaffold proteins to study maintenance and modulation of native nerve terminals in Drosophila, an experimental system that is well suited for genetics, electrophysiology and imaging in native intact synapses. Proposed experiments are based on: (a) our development of a new method for tracking single DCVs in native neurons for minutes (SPAIM), (b) the discovery of a new mechanism for delivering DCVs to sequential synaptic release sites called vesicle circulation, (c) the demonstration that synaptic neuropeptide release can be evoked by cAMP without Ca2+ influx, (d) findings suggesting that inositol trisphosphate receptors (IP3Rs) control translocation of regulatory and scaffold proteins in the nerve terminal, and (e) the ability to directly monitor activity-dependent release from a single vesicle in a native synapse for the first time. Here three main questions will be addressed with GFP-based imaging in Drosophila neurons: 1. How does vesicle circulation vary with nerve terminal shape, disease and acute injury? 2. How do single DCVs release their contents in response to different stimuli and why is release reduced with inhibition of retrograde transport, a condition associated with neurodegenerative diseases? 3. How does presynaptic signaling induce translocation of regulatory proteins within the nerve terminal? These studies will yield fundamental insights into the maintenance of terminals and the regulation of release of neuropeptides and their cotransmitters. Furthermore, the proposal will reveal how these processes are affected by acute nerve injury and diseases such as Fragile X syndrome and Lou Gehrig's disease (ALS).

Public Health Relevance

This project will elucidate mechanisms that regulate neuropeptide delivery to and release from nerve terminals. These mechanisms are essential to understanding neuropeptide control of pain perception, sleep and mood. Furthermore, they provide insights into the disruption of nerve terminal function by neurodegenerative diseases that affect axonal transport.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS032385-17
Application #
8471204
Study Section
Special Emphasis Panel (ZRG1-MDCN-B (04))
Program Officer
Whittemore, Vicky R
Project Start
1995-08-04
Project End
2017-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
17
Fiscal Year
2013
Total Cost
$375,968
Indirect Cost
$106,081
Name
University of Pittsburgh
Department
Pharmacology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Cavolo, Samantha L; Bulgari, Dinara; Deitcher, David L et al. (2016) Activity Induces Fmr1-Sensitive Synaptic Capture of Anterograde Circulating Neuropeptide Vesicles. J Neurosci 36:11781-11787
Roland, Bartholomew P; Zeccola, Alison M; Larsen, Samantha B et al. (2016) Structural and Genetic Studies Demonstrate Neurologic Dysfunction in Triosephosphate Isomerase Deficiency Is Associated with Impaired Synaptic Vesicle Dynamics. PLoS Genet 12:e1005941
Rao, Kavitha; Stone, Michelle C; Weiner, Alexis T et al. (2016) Spastin, atlastin, and ER relocalization are involved in axon but not dendrite regeneration. Mol Biol Cell 27:3245-3256
Wong, Man Yan; Cavolo, Samantha L; Levitan, Edwin S (2015) Synaptic neuropeptide release by dynamin-dependent partial release from circulating vesicles. Mol Biol Cell 26:2466-74
Cavolo, Samantha L; Zhou, Chaoming; Ketcham, Stephanie A et al. (2015) Mycalolide B dissociates dynactin and abolishes retrograde axonal transport of dense-core vesicles. Mol Biol Cell 26:2664-72
Li, Long; Tian, Xiaolin; Zhu, Mingwei et al. (2014) Drosophila Syd-1, liprin-α, and protein phosphatase 2A B' subunit Wrd function in a linear pathway to prevent ectopic accumulation of synaptic materials in distal axons. J Neurosci 34:8474-87
James, Rebecca E; Hoover, Kendall M; Bulgari, Dinara et al. (2014) Crimpy enables discrimination of presynaptic and postsynaptic pools of a BMP at the Drosophila neuromuscular junction. Dev Cell 31:586-98
Bulgari, Dinara; Zhou, Chaoming; Hewes, Randall S et al. (2014) Vesicle capture, not delivery, scales up neuropeptide storage in neuroendocrine terminals. Proc Natl Acad Sci U S A 111:3597-601
Lloyd, Thomas E; Machamer, James; O'Hara, Kathleen et al. (2012) The p150(Glued) CAP-Gly domain regulates initiation of retrograde transport at synaptic termini. Neuron 74:344-60
Wong, Man Yan; Zhou, Chaoming; Shakiryanova, Dinara et al. (2012) Neuropeptide delivery to synapses by long-range vesicle circulation and sporadic capture. Cell 148:1029-38

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