Improved transduction efficiency of a lentiviral vector for neuron-specific retrograde gene transfer by optimizing the junction of fusion envelope glycoprotein

Abstract

The vector for neuron-specific retrograde gene transfer (NeuRet) is a pseudotype of human immunodeficiency virus type 1 (HIV-1)-based vector with fusion glycoprotein type C (FuG-C), which consists of the N-terminal region of the extracellular domain of rabies virus glycoprotein (RVG) and the membrane-proximal region of the extracellular domain and the transmembrane/cytoplasmic domains of vesicular stomatitis virus glycoprotein (VSVG). The NeuRet vector shows a high efficiency of gene transfer through retrograde axonal transport and transduces selectively neuronal cells around the injection site. We aimed to improve the efficiency of retrograde gene transfer of the NeuRet vector by optimizing the junction of RVG and VSVG segments in fusion glycoproteins in their membrane-proximal region. We produced various types of fusion glycoproteins, in which the junction of the two glycoprotein segments diverged in the membrane-proximal region and used for pseudotyping of HIV-1-based vector to evaluate the in vivo gene transfer efficiency after intrastriatal injection. We found a novel type of fusion glycoprotein termed type E (FuG-E) that yielded enhanced efficiency of retrograde gene delivery, showing neuron-specific transduction surrounding the injection site. The NeuRet vector pseudotyped with FuG-E displayed the improved efficiency of retrograde gene transfer into different neural pathways compared with the original vector pseudotyped with FuG-C. Our vector system with FuG-E provides a powerful tool for gene therapeutic trials of neurological and neurodegenerative diseases and for the study of the mechanisms of neural networks underlying various brain functions.