Enhanced Central Nervous System Transduction with Lentiviral Vectors Pseudotyped with RVG/HIV-1gp41 Chimeric Envelope Glycoproteins

Abstract

To investigate the potential benefits which may arise from pseudotyping the HIV-1 lentiviral vector with its homologous gp41 envelope glycoprotein (GP) cytoplasmic tail (CT), we created chimeric RVG/HIV-1gp41 GPs composed of the extracellular and transmembrane sequences of RVG and either the full-length gp41 CT or C terminus gp41 truncations sequentially removing existing conserved motifs. Lentiviruses (LVs) pseudotyped with the chimeric GPs were evaluated in terms of particle release (physical titer), biological titers, infectivity, and in vivo central nervous system (CNS) transduction. We report here that LVs carrying shorter CTs expressed higher levels of envelope GP and showed a higher average infectivity than those bearing fulllength GPs. Interestingly, complete removal of GP CT led to vectors with the highest transduction efficiency. Removal of all Cterminal gp41 CT conserved motifs, leaving just 17 amino acids (aa), appeared to preserve infectivity and resulted in a significantly increased physical titer. Furthermore, incorporation of these 17 aa in the RVG CT notably enhanced the physical titer. In vivo stereotaxic delivery of LV vectors exhibiting the best in vitro titers into rodent striatum facilitated efficient transduction of the CNS at the site of injection. A particular observation was the improved retrograde transduction of neurons in connected distal sites that resulted from the chimeric envelope R5 which included the "Kennedy" sequence (Ken) and lentivirus lytic peptide 2 (LLP2) conserved motifs in the CT, and although it did not exhibit a comparable high titer upon pseudotyping, it led to a significant increase in distal retrograde transduction of neurons. IMPORTANCEIn this study, we have produced novel chimeric envelopes bearing the extracellular domain of rabies fused to the cytoplasmic tail (CT) of gp41 and pseudotyped lentiviral vectors with them. Here we report novel effects on the transduction efficiency and physical titer of these vectors, depending on CT length and context. We also managed to achieve increased neuronal transduction in vivo in the rodent CNS, thus demonstrating that the efficiency of these vectors can be enhanced following merely CT manipulation. We believe that this paper is a novel contribution to the field and opens the way for further attempts to surface engineer lentiviral vectors and make them more amenable for applications in human disease.

Rabies Virus Envelope Glycoprotein Targets Lentiviral Vectors to the Axonal Retrograde Pathway in Motor Neurons

“…In addition, lentiviral vector transduction of dendritic cells involved endosomal trafficking, and its efficiency was enhanced by suppressing autophagy (59). Indeed, we have recently reported an increase in retrograde transduction in the brain of lentiviral vectors pseudotyped with a chimeric RV-G bearing a portion of gp41 for its cytoplasmic tail (60). We have also observed that incorporation of different yet more efficient fusogens (61) in combination with surface-expressed antibodies targeting neuromuscular junction receptors onto the lentiviral vector surface enhances the ability of retrogradely transported vectors to transduce motor neurons within microfluidic motor neuron cultures following axonal chamber application (50).…”

G gene-deficient single-round rabies viruses for neuronal circuit analysis

“…Lentivirus vector particles are usually pseudotyped with VSV G to enlarge their tropism, but also RABV G can be used to more specifically target neurons (Cronin et al, 2005;Trabalza et al, 2014). A fundamental difference between lentiviruses and (onco-) retroviruses like mouse leukemia virus (MLV) is the inability of the latter to transduce postmitotic cells like neurons.…”

Pseudotyped Lentiviral Vectors: One Vector, Many Guises

“…In particular, HiRet (FuG-B/B2) and FuG-E are highly efficient at transduction and retrograde transport. [57][58][59][60] The G protein from a related Rhabdovirus, Mokola virus (MOKV-G), also shows similar ability to pseudotype LVs. MOKV infects cats and other sub-Saharan mammals, but rarely humans.…”