In Vivo Efficacy of Measles Virus Fusion Protein-Derived Peptides Is Modulated by the Properties of Self-Assembly and Membrane Residence

Abstract

Measles virus (MV) infection is undergoing resurgence and remains one of the leading causes of death among young children worldwide despite the availability of an effective measles vaccine. MV infects its target cells by coordinated action of the MV hemagglutinin (H) and fusion (F) envelope glycoproteins; upon receptor engagement by H, the prefusion F undergoes a structural transition, extending and inserting into the target cell membrane and then refolding into a postfusion structure that fuses the viral and cell membranes. By interfering with this structural transition of F, peptides derived from the heptad repeat (HR) regions of F can inhibit MV infection at the entry stage. In previous work, we have generated potent MV fusion inhibitors by dimerizing the F-derived peptides and conjugating them to cholesterol. We have shown that prophylactic intranasal administration of our lead fusion inhibitor efficiently protects from MV infection in vivo. We show here that peptides tagged with lipophilic moieties self-assemble into nanoparticles until they reach the target cells, where they are integrated into cell membranes. The selfassembly feature enhances biodistribution and the half-life of the peptides, while integration into the target cell membrane increases fusion inhibitor potency. These factors together modulate in vivo efficacy. The results suggest a new framework for developing effective fusion inhibitory peptides.IMPORTANCE Measles virus (MV) infection causes an acute illness that may be associated with infection of the central nervous system (CNS) and severe neurological disease. No specific treatment is available. We have shown that fusion-inhibitory peptides delivered intranasally provide effective prophylaxis against MV infection. We show here that specific biophysical properties regulate the in vivo efficacy of MV F-derived peptides.

Lipidation increases antiviral activities of coronavirus fusion-inhibiting peptides

“…4 and 5), suggesting that these two lipids tether HR2 peptides near viruses throughout their endocytosis. That lipid conjugations allow HR2 peptides to accumulate in endosomes, thereby blocking "slow"-entering viruses, has been recently documented (Figueira et al, 2016;Lee et al, 2011), and is again shown here with the CoVs. However, when the virus entry was accelerated, through TMPRSS2 overexpression, the cholesterol-conjugated HR2 lost much , 10 µM E64d, or 100 nM bafilomycin A1 (BafA1) for 1 h, then transduced with WT or S2′ mutant (S2′ mut) MERS pps, without removing previously applied inhibitors.…”

Quantitative analysis of molecular partition towards lipid membranes using surface plasmon resonance

“…σ suggests the derivatized peptide may self-associate in membranes, which may be the basis of complex dissociation kinetics. Additionally, HRC4 is able to self-assemble in solution44. We modified equation (S24) to account for two distinct peptide populations, either monomeric or aggregated, for instance, and adequately fitted the resulting equation (1) to the dissociation data (Fig.…”

Fusion Inhibitory Lipopeptides Engineered for Prophylaxis of Nipah Virus in Primates

“…We replaced the traditional PEG flexible linker with dPEG so that chain length can be modulated at the stage of peptide synthesis [31]. For comparison with the cholesterol moiety used in the prototype VIKI-PEG 4 -Chol peptide we studied tocopherol (Table 1), because tocopherol's specific interaction with membranes may improve the biophysical characteristics of the lipopeptide [12].…”

“…We compared the efficacy of VIKI-dPEG4-Chol and VIKI-dPEG4-Toco against NiV in hamsters ( Figure 2). We previously determined an LD [32] and established pharmacokinetics and biodistribution of HRC-derived peptides in hamsters and mice [11,12,17]. In this study, we determined the appropriate dose to target both upper and lower respiratory tract after i.n.…”

“…Nipah virus F-mediated entry into target cells can be specifically targeted by fusion-inhibitory peptides that interfere with this initial step of viral entry by blocking formation of the 6-helix bundle. We have shown that fusion inhibitory peptide entry inhibitors, if conjugated to lipid moieties linked to the amino acid sequence by a flexible linker, can be highly effective inhibitors of NiV central nervous system (CNS) infection [10][11][12][13]. Exploiting the criteria that emerged from our previous biophysical studies, we designed a set of new lipopeptides with an amino acid sequence that confers greater stability to protease degradation and improved efficacy in vitro and in vivo.…”