The goal of this research is to elucidate principles and mechanisms that govern the assembly of neural circuits. The work focuses on the role of the target field, and in particular target-derived growth factors, in the control of neuronal survival and the establishment of synaptic connections between postganglionic sympathetic neurons and their presynaptic partners, and the differentiation of distinct classes of cutaneous sensory neurons. Proposed experiments address mechanisms and functions of the prototypical target-derived neurotrophic growth factor, nerve growth factor (NGF), and its receptor TrkA. NGF, expressed in targets of sympathetic and cutaneous sensory neurons, promotes target field innervation, survival, and synapse formation in the sympathetic nervous system through retrograde NFG/TrkA signaling. Retrograde NGF/TrkA signaling also controls target innervation, survival, and maturation of cutaneous sensory neurons. A main hypothesis to be tested is whether differential sorting and trafficking of TrkA-containing signaling endosomes account for the unique ability of NGF to support retrograde survival;the NGF family member NT3, an intermediate target- derived growth factor, cannot support retrograde survival. This is especially intriguing since both NGF and NT3 promote TrkA activation and TrkA-dependent axonal extension of sympathetic neurons. The work will assess the contribution of the actin cytoskeleton, and its modulation, during TrkA endosome formation, sorting, maturation, and trafficking. Proposed experiments will also address the exciting hypothesis that TrkA endosomes move retrogradely into cell bodies and then throughout the entire dendritic arbor where they instruct the formation of nascent postsynaptic specializations on dendrites.
A third aim of the proposed work is to test the hypothesis that target-derived NGF signals retrogradely to promote expression of the transcription factor CBF2, which combines with the sensory neuron-subtype specific transcription factor Runx1 to instruct differentiation of non-peptidergic nociceptors. Thus, proposed work will provide insight into how the target field, and target-derived NGF, controls establishment and maintenance of PNS circuits. Since deficits of axonal transport and signaling and synaptic loss underlie forms of neurodegeneration, findings from the proposed work will be insightful not only for understanding normal development but also for maintenance of the nervous system under normal and disease states.

Public Health Relevance

The proposed studies will provide an understanding of how neuronal differentiation and morphology develop and how cell type specificity, survival, and connectivity are achieved. The particular focus is on understanding how a growth factor, called nerve growth factor, promotes survival and directs the differentiation and connectivity of sympathetic and somatosensory neurons. Importantly, since aberrant neuronal signaling is associated with a range of disorders, including neurodevelopmental disorders and degenerative diseases, this work will inform strategies for treatment of these disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS034814-17
Application #
8198880
Study Section
Neurogenesis and Cell Fate Study Section (NCF)
Program Officer
Mamounas, Laura
Project Start
1996-01-01
Project End
2016-04-30
Budget Start
2011-07-01
Budget End
2012-04-30
Support Year
17
Fiscal Year
2011
Total Cost
$358,750
Indirect Cost
Name
Johns Hopkins University
Department
Neurosciences
Type
Schools of Medicine
DUNS #
001910777
City
Baltimore
State
MD
Country
United States
Zip Code
21218
Severson, Kyle S; Xu, Duo; Van de Loo, Margaret et al. (2017) Active Touch and Self-Motion Encoding by Merkel Cell-Associated Afferents. Neuron 94:666-676.e9
Lehigh, Kathryn M; West, Katherine M; Ginty, David D (2017) Retrogradely Transported TrkA Endosomes Signal Locally within Dendrites to Maintain Sympathetic Neuron Synapses. Cell Rep 19:86-100
Orefice, Lauren L; Zimmerman, Amanda L; Chirila, Anda M et al. (2016) Peripheral Mechanosensory Neuron Dysfunction Underlies Tactile and Behavioral Deficits in Mouse Models of ASDs. Cell 166:299-313
Huang, Siyi; O'Donovan, Kevin J; Turner, Eric E et al. (2015) Extrinsic and intrinsic signals converge on the Runx1/CBF? transcription factor for nonpeptidergic nociceptor maturation. Elife 4:e10874
Bai, Ling; Lehnert, Brendan P; Liu, Junwei et al. (2015) Genetic Identification of an Expansive Mechanoreceptor Sensitive to Skin Stroking. Cell 163:1783-1795
Li, Lishi; Ginty, David D (2014) The structure and organization of lanceolate mechanosensory complexes at mouse hair follicles. Elife 3:e01901
Zimmerman, Amanda; Bai, Ling; Ginty, David D (2014) The gentle touch receptors of mammalian skin. Science 346:950-4
Suo, Dong; Park, Juyeon; Harrington, Anthony W et al. (2014) Coronin-1 is a neurotrophin endosomal effector that is required for developmental competition for survival. Nat Neurosci 17:36-45
Mandai, Kenji; Reimert, Dorothy V; Ginty, David D (2014) Linx mediates interaxonal interactions and formation of the internal capsule. Neuron 83:93-103
Rutlin, Michael; Ho, Cheng-Ying; Abraira, Victoria E et al. (2014) The cellular and molecular basis of direction selectivity of A?-LTMRs. Cell 159:1640-51

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