An Elastin-like Polypeptide-fusion peptide targeting capsid-tegument interface as an antiviral against cytomegalovirus infection

The tegument protein pp150 of Human Cytomegalovirus (HCMV) is known to be essential for the final stages of virus maturation and mediates its functions by interacting with capsid proteins. Our laboratory has previously identified the critical regions in pp150 important for pp150-capsid interactions and designed peptides similar in sequence to these regions, with a goal to competitively inhibit capsid maturation. Treatment with a specific peptide (PepCR2 or P10) targeted to pp150 conserved region 2 led to a significant reduction in murine CMV (MCMV) growth in cell culture, paving the way for in vivo testing in a mouse model of CMV infection. However, the general pharmacokinetic parameters of peptides, including rapid degradation and limited tissue and cell membrane permeability, pose a challenge to their successful use in vivo. Therefore, we designed a biopolymer-stabilized elastin-like polypeptide (ELP) fusion construct (ELP-P10) to enhance the bioavailability of P10. Antiviral efficacy and cytotoxic effects of ELP-P10 were studied in cell culture, and pharmacokinetics, biodistribution, and antiviral efficacy were studied in a mouse model of CMV infection. ELP-P10 maintained significant antiviral activity in cell culture, and this conjugation significantly enhanced P10 bioavailability in mouse tissues. The fluorescently labeled ELP-P10 accumulated to higher levels in mouse liver and kidneys as compared to the unconjugated P10. Moreover, viral titers from vital organs of MCMV-infected mice indicated a significant reduction of virus load upon ELP-P10 treatment. Therefore, ELP-P10 has the potential to be developed into an effective antiviral against CMV infection.