In vivo enrichment of genetically manipulated platelets for murine hemophilia B gene therapy.
Abstract
Our previous studies have demonstrated that platelet-targeted factor IX (FIX) gene therapy can introduce sustained platelet-FIX expression in hemophilia B (FIXnull ) mice. In this study, we aimed to enhance platelet-FIX expression in FIXnull mice with O6 -methylguanine-DNA-methyltransferase (MGMT)-mediated in vivo drug selection of transduced cells under nonmyeloablative preconditioning. We constructed a novel lentiviral vector (2bF9/MGMT lentivirus vector), which harbors dual genes, the FIX gene driven by the αIIb promoter (2bF9) and the MGMT P140K gene under the murine stem cell virus promoter. Platelet-FIX expression in FIXnull mice was introduced by 2bF9/MGMT-mediated hematopoietic stem cell transduction and transplantation. The 2bF9/MGMT-transduced cells were effectively enriched after drug selection by O6 -benzylguanine/1,3-bis-2-chloroethyl-1-nitrosourea. There were a 2.9-fold higher FIX antigen and a 3.7-fold higher FIX activity in platelets, respectively, posttreatment compared with pretreatment. When a 6-hr tail bleeding test was used to grade the bleeding phenotype, the clotting time in treated animals was 2.6 ± 0.5 hr. In contrast, none of the FIXnull control mice were able to clot within 6 hr. Notably, none of the ...Continue Reading
References
Autologous and Heterologous Cell Therapy for Hemophilia B toward Functional Restoration of Factor IX
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