The overall goal of this project is to use the genetically tractable model organism C. elegans to dissect the molecular basis of axon regeneration after injury. The small size, transparent body and simple anatomy of C. elegans allows single axons to be severed in vivo and their regrowth studied in depth. In the prior funding period we used large- scale genetic screens in C. elegans to discover conserved genes and pathways that play regrowth-promoting or regrowth-inhibiting roles in vivo. Many of these pathways are distinct from those involved in developmental axon outgrowth. Our large scale screens and analysis of genetic interactions have led to models for the function of these regrowth factors that we will test mechanistically in this proposal. We will define the roles of ne genes that affect regrowth via axonal microtubule dynamics. We will investigate the role of membrane trafficking regulators in axon regrowth. Results from this work will elucidate intrinsic mechanisms that allow mature axons to regrow after damage. In vertebrates, peripheral nerves are capable of regrowth, yet recovery after peripheral nerve trauma is often incomplete. Improved knowledge of regrowth mechanisms could also inform our understanding of why other neurons do not regrow. The mammalian CNS is only minimally capable of regeneration after injury, reflecting the combined effects of an inhibitory environment and of reduced intrinsic regrowth capacity. Our work addresses intrinsic mechanisms that promote or inhibit axon regrowth, a high priority for this field. Some signaling pathways have conserved roles in axon regrowth, suggesting analysis of C. elegans axon regrowth has implications for understanding axon repair mechanisms in medically relevant situations.

Public Health Relevance

The goal of this work is to define fundamental mechanisms of how axons of mature neurons regrow after damage. We use an anatomically simple and genetically tractable model, the nematode C. elegans, to find conserved genes that affect the ability of axons to regrow after injury. These genes include signaling molecules, regulators of the microtubule cytoskeleton, and regulators of membrane traffic. A better understanding of the roles of these molecules in a simple model of regrowth could improve our ability to manipulate the intrinsic growth capacity of damaged axons in therapeutic settings.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
High Priority, Short Term Project Award (R56)
Project #
2R56NS057317-06A1
Application #
8806150
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Jakeman, Lyn B
Project Start
2006-12-01
Project End
2015-03-31
Budget Start
2014-04-01
Budget End
2015-03-31
Support Year
6
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Chen, Lizhen; Liu, Zhijie; Zhou, Bing et al. (2016) CELF RNA binding proteins promote axon regeneration in C. elegans and mammals through alternative splicing of Syntaxins. Elife 5:
Kim, Kyung Won; Jin, Yishi (2015) Neuronal responses to stress and injury in C. elegans. FEBS Lett 589:1644-52
Chen, Lizhen; Chuang, Marian; Koorman, Thijs et al. (2015) Axon injury triggers EFA-6 mediated destabilization of axonal microtubules via TACC and doublecortin like kinase. Elife 4:
Hammarlund, Marc; Jin, Yishi (2014) Axon regeneration in C. elegans. Curr Opin Neurobiol 27:199-207
Chuang, Marian; Goncharov, Alexandr; Wang, Shaohe et al. (2014) The microtubule minus-end-binding protein patronin/PTRN-1 is required for axon regeneration in C. elegans. Cell Rep 9:874-83
Chen, Lizhen; Wang, Zhiping; Ghosh-Roy, Anindya et al. (2011) Axon regeneration pathways identified by systematic genetic screening in C. elegans. Neuron 71:1043-57
Ghosh-Roy, Anindya; Wu, Zilu; Goncharov, Alexandr et al. (2010) Calcium and cyclic AMP promote axonal regeneration in Caenorhabditis elegans and require DLK-1 kinase. J Neurosci 30:3175-83