Pathways in the adult central nervous system (CNS) are unable to regenerate after injury, leaving victims of traumatic nerve damage or degenerative disease severely disabled. Improving the regenerative capacity of the CNS may improve functional recovery, quality of life, as well as decrease overall healthcare costs for many of these patients. A major hurdle, however, is the non-permissive nature of the CNS to axon regeneration. Elucidation of the molecular signaling cascades that inhibits axon re- growth has identified the pivotal role of a common intracellular 'molecular switch' - RhoA GTPase. C3 transferase, a bacterial exoenzyme, inhibits RhoA via ADP- ribosylation and its local application promotes axon re-growth in various CNS injury models. This method of delivery is however limited to a duration of several days, likely insufficient for the regeneration of long axons and sustained neuron survival. To address these issues, we have engineered viral vectors to allow continuous delivery of C3 via gene therapy. A cell-permeable and secretable version of C3 has been developed for more widespread and effective RhoA inactivation. Our objective is to test a variety of different approaches of viral vector - mediated C3 expression to identify the most effective delivery and therapeutic window for CNS axon regeneration in a model of optic nerve injury, the optic nerve crush (ONC). The successful results of these experiments will lay the foundation for the extension of our approach to treat other neuropathology's including spinal cord injury, brain injury, and stroke and neurodegenerative diseases.

Public Health Relevance

C3 transferase, a bacterial exoenzyme, inhibits RhoA and its local application promotes axon growth regeneration in various CNS injury models. We have generated viral vectors to control the expression level and the continuous delivery of various forms of C3 transferase via gene therapy. We propose to test the ability of these C3 viral vectors to increase axon regeneration in a common in vivo rat model of CNS injury.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Small Research Grants (R03)
Project #
1R03NS091699-01
Application #
8873702
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Jakeman, Lyn B
Project Start
2015-03-01
Project End
2017-02-28
Budget Start
2015-03-01
Budget End
2016-02-29
Support Year
1
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Emory University
Department
Neurosurgery
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Gutekunst, Claire-Anne; Tung, Jack K; McDougal, Margaret E et al. (2016) C3 transferase gene therapy for continuous conditional RhoA inhibition. Neuroscience 339:308-318