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

[junctional epidermolysis bullosa]

Mutations of the LAMB 3 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 LAMB 3 (IAP ) breeding pairs underwent ultrasound guided intra-amniotic injection of lentiviral vector encoding the murine LAMB 3 gene at embryonic day 8 (E 8 ). Gene expression was monitored by immunohistochemistry . The transgenic laminin-β 3 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 ∼60 % of hemidesmosomal structures was also noted . Although we could correct the skin phenotype in 11 .9 % of homozygous LAMB 3 (IAP ) mice , none survived beyond 48 h . However , skin transplants from treated E 18 homozygous LAMB 3 (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 .