Mitotically Stable Lentiviral Episomes for Stem Cell Gene Therapy

Project: Research project

Description

? DESCRIPTION (provided by applicant): Stable genetic modification of autologous stem cells using HIV-1 derived lentivirus vectors confers clinical benefit in patients with inherited disorder of hematopoiesis and immunity. Broad tropism for gene delivery to diverse tissues, stable passage of the proviral integrant to all progeny, and the ability to scale production for clinical use provide strong motivation for using this vector system in stem cell gene therapy. Nevertheless, instances of insertional activation of endogenous genes continue to raise concerns for the use of integrating lentivectors in hematopoietic stem cell gene therapy. Current non- integrating vectors provide long-term expression in postmitotic tissues, but failure to replicate the episomal vector genome leads to rapid loss in dividing stem cell populations. We recently reported the development of a novel, non-integrating episomal lentivector that faithfully replicates through cell division and expresses a gene of interest - without selection. In distinctin to similar vectors, this anchored Non-Integrating LentiVector (aNILV) avoids heterologous viral sequences and relies on human ?-interferon nuclear scaffold/matrix attachment region (S/MAR) locus sequences. Our principal hypothesis is that aNILV will optimize biosafety and provide long-term correction of bone marrow failure in a murine model of Fanconi Anemia. We will develop a second-generation episome vector design (aNILV-II) additionally capable of conversion to backbone-free minicircles to further enhance biosafety and long-term transgene expression. This proposal is uniquely responsive to PAS-13-006: New Directions in Hematology Research (SHINE-II). SPECIFIC AIM 1 [A] Demonstrate aNILV-mediated phenotype correction, biosafety and clonal diversity under physiologic and pharmacological selection in a murine model of Fanconi Anemia (FA) associated bone marrow failure. SPECIFIC AIM 1 [B] Track molecular persistence and multilineage expression during serial transplantation of aNILV transduced human CD34 progenitor cells in immunodeficient mice. SPECIFIC AIM 1 [C] Design a minicircle-delivering lentivector (aNILV-II) and systematically determine its performance in clonally-derived cell lines and in vivo. The proposed platform promises to reconcile the efficiency of lentivector delivery with the inherent biosafety of episomally maintained genomes. This vector system will have a strong translational impact on stem cell gene therapy and may allow for significant cost savings, currently associated with long- term integration site surveillance in patients.
StatusFinished
Effective start/end date9/25/158/31/18

Funding

  • National Institutes of Health: $242,550.00
  • National Institutes of Health: $242,550.00

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Cell- and Tissue-Based Therapy
Genetic Therapy
Plasmids
Stem Cells
Matrix Attachment Regions
Fanconi Anemia
Nuclear Matrix
Bone Marrow
Genome
Genes
Lentivirus
Tropism
Cost Savings
Insertional Mutagenesis
Hematopoiesis
Hematology
Hematopoietic Stem Cells
Transgenes
Cell Division
Interferons

ASJC

  • Medicine(all)