Author ORCID Identifier

https://orcid.org/0000-0002-6647-3367

Date Available

5-13-2024

Year of Publication

2024

Document Type

Master's Thesis

Degree Name

Master of Science in Medical Sciences (MSMS)

College

Medicine

Department/School/Program

Medical Sciences

Advisor

Dr. Andrew N. Stewart

Co-Director of Graduate Studies

Dr. John C. Gensel

Abstract

Spinal cord injury poses multiple regeneration barriers, including neuronal-intrinsic and extrinsic factors. Overcoming these barriers has stood as a longstanding challenge in neuroscience. A well-studied mechanism to promote spinal cord regeneration and locomotor recovery is activating the PI3K/mTOR pathway by knocking out phosphatase and tensin homolog protein (PTEN). PTEN knockout (PTEN-KO) studies have traditionally used adeno-associated virus (AAV) viral vectors to improve functional recovery. The use of traditional AAV serotypes to induce PTEN-KO has shown promise to improve functional recovery in rodent models; however, these approaches show significant limitations for translational utility. Firstly, the use of traditional AAV serotypes to induce PTEN-KO requires injection at the location of cell bodies within the brain, which presents multiple technical challenges. To counteract this issue, we utilize a relatively novel AAV serotype that utilizes a retrograde transport mechanism, termed, retrogradely transported AAV (AAVrg) viral vectors; the use of AAVrg allows us to introduce genetic therapies within the spinal cord by directly injecting at the site of injury which provides for a more translatable model for SCI treatment. Our study aims to investigate delivering gene therapies using AAVrg vectors by modulating the mTOR pathway. Our investigation starts by investigating the use of AAVrg to induce PTEN-KO to restore locomotor recovery and then by activating AKT/PKB, a downstream protein engaged after PTEN-KO. This thesis aims to characterize the extent to which AAVrg can be utilized in SCI by investigating transfection efficiency within the spinal cord. A second aim is to elucidate the extent of behavioral recovery through the use of the Basso Mouse Scale (BMS) locomotor rating scale. Lastly, we aim to replicate PTEN-KO behavioral recovery patterns by activating AKT/PKB using an inducible promoter system to bypass deleterious effects associated with permanent PTEN-KO. By investigating the use of AAVrg and new methods to improve locomotor recovery, we aim to identify and characterize therapies with better translatability for treating SCI.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2024.178

Funding Information

This study was supported by:

  • The Wings for Life Foundation under contract number WFL-US-13/22
  • The Craig H. Neilsen Foundation under award #LOIID 998439,
  • the National Institute of Neurological Disorders and Stroke (NINDS) under Award: R01NS116068
  • The Spinal Cord and Brain Injury Research Center Endowed Chair #5
  • African American Research Training Scholars Program (AARTS)

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