Our recent clinical trial using adeno-associated viral vectors (AAV) to deliver Mini-Dystrophin to the muscle of patients with Duchenne muscular dystrophy (DMD) was met with an unexpected result; after treatment, a Dystrophin-specific T-cell response was found in two patients, which was related to revertant fiber development prior to therapy. These Dystrophin-specific T cells have the potential to eradicate all genetically modified muscle resulting in an ineffective therapy, as well as presenting a general concern for gene therapy communities in general. Currently, no strategy exists to avoid transgene-specific CTLs, whether they are pre-existing or therapy- induced, and systemic long-term immunosuppression is considered a non-viable option. However, particular viruses found in nature have evolved a potential solution to this dilemma by synthesizing small peptides that inhibit antigen presentation only in transduced cells. In preliminary experiments, we demonstrate that the cellular synthesis of these viral inhibitory peptides (termed VIPRs) prevents the surface presentation of a well-defined antigen, thus protecting transduced cells from the host's immune response. In the current proposal, we will use a canine DMD model (GRMD) to evaluate the evasion ability of VIPRs from Dystrophin- specific CTL-mediated elimination of AAV transduced muscles. First, we will test whether the utilization of VIPRs can block the induction of a Dystrophin-specific CTL response after AAV muscle injection (Aim 1). Next, we will study whether the application of VIPRs will help AAV transduced muscle fibers escape pre-existing Dystrophin-specific CTL-mediated elimination (Aim 2). To decrease the vector cassette size for efficient virion package and/or to enhance the evasion ability of VIPRs, we will optimize the VIPR domains and test the immune evasion capacity of mutant variants (Aim 3). By delivering VIPRs and mini-dystrophin in the same vector, this approach ensures that antigen presentation will be attenuated only in AAV- transduced cells without systemic side effects on the immune system (as would be the case using immunosuppressive drugs or by the application of regulatory T-cells). Collectively, this proposal outlines a promising strategy to overcome our clinical DMD observations and concerns for gene therapy studies in general, by creating an AAV vector capable of avoiding the host's immune response to a foreign protein.

Public Health Relevance

In this proposal we will study the immune-mediated clearance of genetically modified cells in dystrophic muscle. Then, we will rely on an approach taken from human viruses to evade the host's immune response which can kill gene therapy treated cells. This evasion technique will be employed during therapeutic treatment using a viral gene therapy vector in large animal models of Duchenne muscular dystrophy (DMD). Positive outcomes from these studies will justify moving this strategy forward into a clinical trial to treat patients wit DMD.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR064369-03
Application #
8925675
Study Section
Gene and Drug Delivery Systems Study Section (GDD)
Program Officer
Cheever, Thomas
Project Start
2013-09-17
Project End
2016-08-31
Budget Start
2015-09-01
Budget End
2016-08-31
Support Year
3
Fiscal Year
2015
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Pharmacology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Chai, Zheng; Samulski, R Jude; Li, Chengwen (2018) Nab Escaping AAV Mutants Isolated from Mouse Muscles. Bio Protoc 8:
Song, Liujiang; Llanga, Telmo; Conatser, Laura M et al. (2018) Serotype survey of AAV gene delivery via subconjunctival injection in mice. Gene Ther 25:402-414
Shao, Wenwei; Chen, Xiaojing; Samulski, Richard J et al. (2018) Inhibition of antigen presentation during AAV gene therapy using virus peptides. Hum Mol Genet 27:601-613
Shao, Wenwei; Earley, Lauriel F; Chai, Zheng et al. (2018) Double-stranded RNA innate immune response activation from long-term adeno-associated virus vector transduction. JCI Insight 3:
Brown, Nolan; Song, Liujiang; Kollu, Nageswara R et al. (2017) Adeno-Associated Virus Vectors and Stem Cells: Friends or Foes? Hum Gene Ther 28:450-463
Llanga, Telmo; Nagy, Nadia; Conatser, Laura et al. (2017) Structure-Based Designed Nano-Dysferlin Significantly Improves Dysferlinopathy in BLA/J Mice. Mol Ther 25:2150-2162
Hirsch, Matthew L; Conatser, Laura M; Smith, Sara M et al. (2017) AAV vector-meditated expression of HLA-G reduces injury-induced corneal vascularization, immune cell infiltration, and fibrosis. Sci Rep 7:17840
Nagy, Nadia; Nonneman, Randal J; Llanga, Telmo et al. (2017) Hip region muscular dystrophy and emergence of motor deficits in dysferlin-deficient Bla/J mice. Physiol Rep 5:
MacLeod, Daniel T; Antony, Jeyaraj; Martin, Aaron J et al. (2017) Integration of a CD19 CAR into the TCR Alpha Chain Locus Streamlines Production of Allogeneic Gene-Edited CAR T Cells. Mol Ther 25:949-961
Xiao, Ping-Jie; Mitchell, Angela M; Huang, Lu et al. (2016) Disruption of Microtubules Post-Virus Entry Enhances Adeno-Associated Virus Vector Transduction. Hum Gene Ther 27:309-24

Showing the most recent 10 out of 27 publications