In adults, axons in the central nervous system (CNS) generally fail to regenerate after they are lost to injury or disease, leading to permanent and incurable disability. Axon growth is prevented by a hostile growth environment, as well as a developmental loss in the intrinsic capacity for axon growth as CNS neurons age. Transcription factors (TFs) interact with DNA and coordinate the production of broad sets of cellular materials, and have emerged as important therapeutic targets to boost regenerative ability within injured neurons. For example, forced re-expression of a pro-regenerative TF called KLF6 in adult neurons can improve their capacity for axon growth after spinal injury. We will now test three complementary and mutually supportive strategies to enhance the promising pro-regenerative properties of KLF6. First, using a novel bioinformatics pipeline, we have predicted additional TFs that functionally interact with KLF6 and verified their ability to synergistically enhance axon growth when combined with KLF6 in cell culture models of axon growth. We will therefore perform in vivo tests of three selected factors, EOMES, NR5A2, and RARB, for the ability to enhance KLF6?s pro-regenerative properties in animal models of spinal cord injury. Second, we will supplement these TF interventions with transplants of growth- permissive stem cells into sites of spinal injury. These grafts will alleviate persistent growth inhibition in the spinal cord environment, and thus unmask the pro-regenerative effects of TF treatments. Finally, we will harness a newly developed gene therapy vector that enables retrograde delivery of genes with unprecedented efficiency. Injection of this vector to the spinal cord results in widespread gene expression in injured neurons throughout the brainstem, midbrain, and motor cortex. This delivery system engages a larger number and a wider diversity of cell types than the current practice of direct brain injection, thus maximizing the chance of achieving functional gains after spinal injury. Throughout these aims, tissue clearing and 3D microscopy will reveal new anatomical details of the evoked regeneration. Bringing together these cutting-edge improvements to a TF-centered strategy will move the field toward novel and effective treatments for individuals suffering from the debilitating consequences of CNS injury.

Public Health Relevance

A major challenge to treating trauma to the brain and spinal cord is that axons, the cellular processes that carry information in the nervous system, are unable to regenerate after injury. Using a rodent model of spinal cord injury, we are testing cutting-edge gene therapy approaches to boost regenerative ability in injured nerve cells and help restore connections across the injury site.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS083983-07
Application #
9890010
Study Section
Clinical Neuroplasticity and Neurotransmitters Study Section (CNNT)
Program Officer
Bambrick, Linda Louise
Project Start
2013-07-15
Project End
2024-02-29
Budget Start
2020-03-01
Budget End
2021-02-28
Support Year
7
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Marquette University
Department
Other Basic Sciences
Type
Sch Allied Health Professions
DUNS #
046929621
City
Milwaukee
State
WI
Country
United States
Zip Code
53201
Venkatesh, Ishwariya; Mehra, Vatsal; Wang, Zimei et al. (2018) Developmental Chromatin Restriction of Pro-Growth Gene Networks Acts as an Epigenetic Barrier to Axon Regeneration in Cortical Neurons. Dev Neurobiol 78:960-977
Venkatesh, Ishwariya; Blackmore, Murray G (2017) Selecting optimal combinations of transcription factors to promote axon regeneration: Why mechanisms matter. Neurosci Lett 652:64-73
Wang, Zimei; Winsor, Kristen; Nienhaus, Christopher et al. (2017) Combined chondroitinase and KLF7 expression reduce net retraction of sensory and CST axons from sites of spinal injury. Neurobiol Dis 99:24-35
Jayaprakash, Naveen; Wang, Zimei; Hoeynck, Brian et al. (2016) Optogenetic Interrogation of Functional Synapse Formation by Corticospinal Tract Axons in the Injured Spinal Cord. J Neurosci 36:5877-90
Wang, Zimei; Reynolds, Ashley; Kirry, Adam et al. (2015) Overexpression of Sox11 promotes corticospinal tract regeneration after spinal injury while interfering with functional recovery. J Neurosci 35:3139-45
Simpson, Matthew T; Venkatesh, Ishwariya; Callif, Ben L et al. (2015) The tumor suppressor HHEX inhibits axon growth when prematurely expressed in developing central nervous system neurons. Mol Cell Neurosci 68:272-83