In Utero Gene Therapy (IUGT) Using GLOBE Lentiviral Vector Phenotypically Corrects the Heterozygous Humanised Mouse Model and Its Progress Can Be Monitored Using MRI Techniques

Abstract

In utero gene therapy (IUGT) to the fetal hematopoietic compartment could be used to treat congenital blood disorders such as β-thalassemia. A humanised mouse model of β-thalassemia was used, in which heterozygous animals are anaemic with splenomegaly and extramedullary hematopoiesis. Intrahepatic in utero injections of a β globin-expressing lentiviral vector (GLOBE), were performed in fetuses at E13.5 of gestation. We analysed animals at 12 and 32 weeks of age, for vector copy number in bone marrow, peripheral blood liver and spleen and we performed integration site analysis. Compared to noninjected heterozygous animals IUGT normalised blood haemoglobin levels and spleen weight. Integration site analysis showed polyclonality. The left ventricular ejection fraction measured using magnetic resonance imaging (MRI) in treated heterozygous animals was similar to that of normal non-β-thalassemic mice but significantly higher than untreated heterozygous thalassemia mice suggesting that IUGT ameliorated poor cardiac function. GLOBE LV-mediated IUGT normalised the haematological and anatomical phenotype in a heterozygous humanised model of β-thalassemia.

Ionizable lipid nanoparticles for in utero mRNA delivery

“…Luminescence in fetuses injected with jetPEI.luc was both qualitatively and quantitatively similar to our lowest-performing LNPs. The high survival rates from injections with our LNPs (>90%) are comparable to ours and others’ previous work with vitelline vein injections ( 5 , 63 , 64 ). The reduction in survival (although not statistically significant) of LNP MC3.luc compared to our LNPs may indicate increased toxicity of MC3.luc.…”

Therapy Development by Genome Editing of Hematopoietic Stem Cells

“…For further progress here, major hurdles associated with target tissue specificity, immunogenicity, biodistribution and efficacy need to be overcome. Similarly, the concept of in utero gene therapy [58,60,61], which offers the opportunity for early clinical intervention at significantly reduced use of GMP-grade reagents, may provide an alternative solution to resource-demanding ex vivo HSC gene editing. For further progress here, additional data in large animal models and new legislations and guidelines need to be put in place first.…”

“…Findings for therapy by gene addition indicate that gene editing, too, might benefit from selective HSC depletion by delivery of antibody-drug conjugates[55] and for suitable disorders, such as FA, from engraftment of corrected cells without conditioning[14]. Steps shown for In vivo editing are in part extrapolated for HSC-targeted approaches of gene addition[56][57][58] and in part based on the latest developments and concepts in the delivery of gene editing components and mRNAs[59][60][61][62].…”

Envisioning treating genetically-defined urinary tract malformations with viral vector-mediated gene therapy

“…Lentiviral vectors can hold larger cargoes than AAV vectors and, by virtue of integrating into the genome of targeted cells, they may have advantages over AAVs in producing long-term transduced gene expression especially in cells that have a high turnover beyond the fetal period [62]. As for AAV vectors, lentivirus vectors hold promise for delivery of genes into mouse fetuses [63,64]. The interested reader is also referred to a comprehensive catalogue of preclinical gene transfer studies into the kidney, with comparisons of outcomes between protocols that used either AAV or lentiviral vectors [65].…”