Developments in Cell-Penetrating Peptides as Antiviral Agents and as Vehicles for Delivery of Peptide Nucleic Acid Targeting Hepadnaviral Replication Pathway

Abstract

Alternative therapeutic approaches against chronic hepatitis B virus (HBV) infection need to be urgently developed because current therapies are only virostatic. In this context, cell penetration peptides (CPPs) and their Peptide Nucleic Acids (PNAs) cargoes appear as a promising novel class of biologically active compounds. In this review we summarize different in vitro and in vivo studies, exploring the potential of CPPs as vehicles for intracellular delivery of PNAs targeting hepadnaviral replication. Thus, studies conducted in the duck HBV (DHBV) infection model showed that conjugation of (D-Arg)8 CPP to PNA targeting viral epsilon (ε) were able to efficiently inhibit viral replication in vivo following intravenous administration to ducklings. Unexpectedly, some CPPs, (D-Arg)8 and Decanoyl-(D-Arg)8, alone displayed potent antiviral effect, altering late stages of DHBV and HBV morphogenesis. Such antiviral effects of CPPs may affect the sequence-specificity of CPP-PNA conjugates. By contrast, PNA conjugated to (D-Lys)4 inhibited hepadnaviral replication without compromising sequence specificity. Interestingly, Lactose-modified CPP mediated the delivery of anti-HBV PNA to human hepatoma cells HepaRG, thus improving its antiviral activity. In light of these promising data, we believe that future studies will open new perspectives for translation of CPPs and CPP-PNA based technology to therapy of chronic hepatitis B.

Multifunctional Delivery Systems for Peptide Nucleic Acids

“…In the former case, the inhibition of the biological target led to an increased expression of the cystic fibrosis conductance regulator (CTFR) in Calu-3 cells [ 89 ], while in the latter example the sequestration of the given miR promoted a higher expression of the p27Kip1 gene in the breast cancer MDA-MB-231 line [ 90 ]. Both octa-arginine and tetralysine tails were instead found to induce a PNA-mediated decrease of hepatitis B virus replication after intravenous administration in ducklings, with better results in terms of sequence selectivity when the polylysine moiety was conjugated to the given antisense oligomer [ 91 , 92 ].…”

Cell Penetrating Peptides Used in Delivery of Therapeutic Oligonucleotides Targeting Hepatitis B Virus

“…The antiviral efficiency of several oligonucleotides as PNAs and siRNA can be improved by their coupling to CPPs used as vehicles. Indeed, our studies showed that CPPs considerably increased PNAs uptake into the hepatocytes in vitro in primary duck hepatocyte cells and in vivo in duckling [ 9 , 11 , 12 , 37 ]. Otherwise, other studies showed the benefit of siRNA coupling to CPPs on their intracellular delivery [ 38 , 39 ] and on their antiviral activity [ 28 , 40 ].…”

“…The small interfering RNAs (siRNAs), are a promising approach for gene therapy, however their intracellular administration remains difficult. To date, a great variety of delivery system for siRNAs has been investigated such as lipids, polymers, aptamers and cell penetrating peptides (CPPs) [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. In this regard, CPPs appear as a new class of transporters, which increase intracellular uptake of biologically active molecules including siRNAs [ 45 ] ( Figure 2 ).…”

“…The oligonucleotides can to be associated covalently with several sugars such as Galactose alone or Lactose. Certainly, the synthesis of these carbohydrate-conjugates has been documented [ 37 , 59 ] and the results showed that the coupling of these oligonucleotides with carbohydrates enhance their entry into the hepatocyte cell and their stability. In addition, the asialoglycoproteins receptors (ASGP-R), which are found on the hepatocyte cell membranes, were the first mammalian lectins defined.…”

“…Consequently, carbohydrate-siRNA conjugates exhibit a strong gene silencing levels into the liver both in vitro, in hepatoma cell lines and in vivo, in murine models [ 59 ]. Moreover, we evaluated the anti-HBV activity of sugar-modified CPP-PNA conjugates in the HepaRG human hepatoma cell line and our results demonstrated that treatment of HBV-infected HepaRG cells by anti-S PNA coupled to Lactose increases its uptake and decreases HBsAg release [ 37 ].…”