Early intra-amniotic gene transfer using lentiviral vector improves skin blistering phenotype in a murine model of Herlitz junctional epidermolysis bullosa

Abstract

Mutations of the LAMB3 gene cause a lethal form of junctional epidermolysis bullosa (JEB). We hypothesized that early intra-amniotic gene transfer in a severe murine model of JEB would improve or correct the skin phenotype. Time-dated fetuses from heterozygous LAMB3 IAP breeding pairs underwent ultrasound guided intra-amniotic injection of lentiviral vector encoding the murine LAMB3 gene at embryonic day 8 (E8). Gene expression was monitored by immunohistochemistry. The transgenic laminin-b3 chain was shown to assemble with its endogenous partner chains, resulting in detectable amounts of laminin-332 in the basement membrane zone of skin and mucosa. Ultrastructually, the restoration of B60% of hemidesmosomal structures was also noted. Although we could correct the skin phenotype in 11.9% of homozygous LAMB3 IAP mice, none survived beyond 48 h. However, skin transplants from treated E18 homozygous LAMB3 IAP fetuses maintained normal appearance for 6 months with persistence of normal assembly of laminin-332. These results demonstrate for the first time long-term phenotypic correction of the skin pathology in a severe model of JEB by in vivo prenatal gene transfer. Although survival remained limited due to the limitations of this mouse model, this study supports the potential for treatment of JEB by prenatal gene transfer.

Junctional Epidermolysis Bullosa

“…However, the treatment did not affect the survival of the mice. 60 One of the main problems associated with gene therapy are safety issues concerning the vectors used. Retroviral vectors are inserted uncontrolled into the human genome, with a high chance of deregulating neighboring genes.…”

Toward an orofacial gene regulatory network

“…In addition to genetic rescue, experimental embryonic gene therapy protocols to prevent disease in animal models have been developed for cystic fibrosis (Keswani et al, 2011), Duchenne muscular dystrophy (Koppanati et al, 2010), Herlitz junctional epidermolysis bullosa (Muhle et al, 2006;Endo et al, 2011), thrombotic thrombocytopenic purpura (Niiya et al, 2009), and congenital blindness (Dejneka et al, 2004). Likewise, gene delivery to oral epithelium and developing epidermis is possible during development (Wu et al, 2012).…”

Gene Therapy for Skin Diseases

“…Laminin-332 was incorporated into the basement membrane of the skin and the oral mucosa. Although none of the mice survived more than 48 h, harvested transduced skin showed correct expression of laminin-332 for the 6 mo duration of the experiment (Endo et al 2012).…”

“…Using a model of lethal Herlitz JEB mice with homozygous LAMB3 mutations, Endo et al (2012) attempted to perform in utero gene transfer. A lentiviral vector encoding for LAMB3 was injected into the amniotic space.…”