HiRet/NeuRet Vectors: Lentiviral System for Highly Efficient Gene Transfer Through Retrograde Axonal Transport

Lentiviral vectors are used for a wide range of research applications in the field of neuroscience. Notably, lentiviral tropism can be manipulated by genetically engineering envelope glycoproteins that are essential for vector transduction. The structural and functional analyses of specific neural pathways are crucial to understanding the neural mechanisms underlying brain functions controlled through complex neural circuits. Viral vectors that produce gene transfer via retrograde axonal transport offer a powerful tool for the analysis of neural pathways. We have succeeded in developing novel types of lentiviral vectors for retrograde gene transfer, named “highly efficient retrograde gene transfer” (HiRet) and “neuron-specific retrograde gene transfer” (NeuRet) vectors, by pseudotyping human immunodeficiency virus type 1 with fusion envelope glycoproteins composed of rabies virus glycoprotein segments and vesicular stomatitis virus glycoprotein segments. HiRet/NeuRet vectors show highly efficient retrograde gene transfer in diverse neural pathways in animal models. These vectors have been harnessed for the analysis of specific neural pathways in combination with various genetic approaches for neuromodulation, including optogenetics and chemogenetics. In this chapter, we describe experimental procedures for producing HiRet/NeuRet vectors and injecting them into brain regions, as well as summarize points important to conduct the experiments smoothly and effectively.