Efficient transfer, integration, and sustained long-term expression of the transgene in adult rat brains injected with a lentiviral vector.

TLDR

Clinically acceptable lentiviral vectors could enable sustained delivery of therapeutic genes to diverse somatic tissues. The study aims to construct a safe, replication‑defective, efficient lentiviral vector for in vivo gene delivery. The vector was engineered to be replication‑defective and efficient for in vivo delivery. Promoting reverse transcription within vector particles markedly increased gene transfer efficiency, and a single injection produced sustained, widespread, neuron‑specific transgene expression without pathology, mediated by integrase‑dependent integration.

Abstract

We describe the construction of a safe, replication-defective and efficient lentiviral vector suitable for in vivo gene delivery. The reverse transcription of the vector was found to be a rate-limiting step; therefore, promoting the reaction inside the vector particles before delivery significantly enhanced the efficiency of gene transfer. After injection into the brain of adult rats, sustained long-term expression of the transgene was obtained in the absence of detectable pathology. A high proportion of the neurons in the areas surrounding the injection sites of the vector expressed the transduced beta-galactosidase gene. This pattern was invariant in animals sacrificed several months after a single administration of the vector. Transduction occurs by integration of the vector genome, as it was abolished by a single amino acid substitution in the catalytic site of the integrase protein incorporated in the vector. Development of clinically acceptable derivatives of the lentiviral vector may thus enable the sustained delivery of significant amounts of a therapeutic gene product in a wide variety of somatic tissues.