A General Strategy to Endow Natural Fusion-protein-Derived Peptides with Potent Antiviral Activity

Fusion between the viral and target cell membranes is an obligatory step for the infectivity of all enveloped virus, and blocking this process is a clinically validated therapeutic strategy

An apoA-I mimetic peptide increases LCAT activity in mice through increasing HDL concentration

<p>Lecithin cholesterol acyltransferase (LCAT) plays a key role in the reverse cholesterol transport (RCT) process by converting cholesterol to cholesteryl ester to form mature HDL particles, which in turn deliver cholesterol back to the liver for excretion and catabolism. HDL levels in human plasma are negatively correlated with cardiovascular risk and HDL functions are believed to be more important in atheroprotection. This study investigates whether and how D-4F, an apolipoprotein A-I (apoA-I) mimetic peptide, influences LCAT activity in the completion of the RCT process. We demonstrated that the apparent rate constant value of the LCAT enzyme reaction gives a measure of LCAT activity and determined the effects of free metals and a reducing agent on LCAT activity, showing an inhibition hierarchy of Zn²⁺&#62;Mg²⁺&#62;Ca²⁺ and no inhibition with &#946;-mercaptoethanol up to 10 mM. We reconstituted nano-disc particles using apoA-I or D-4F with phospholipids. These particles elicited good activity <i>in vitro</i> in the stimulation of cholesterol efflux from macrophages through the ATP-binding cassette transporter A1 (ABCA1). With these particles we studied the LCAT activity and demonstrated that D-4F did not activate LCAT <i>in vitro</i>. Furthermore, we have done <i>in vivo</i> experiments with apoE-null mice and demonstrated that D-4F (20 mg/kg body weight, once daily subcutaneously) increased LCAT activity and HDL level as well as apoA-I concentration at 72 hours post initial dosing. Finally, we have established a correlation between HDL concentration and LCAT activity in the D-4F treated mice.</p

Inhibition of Nipah virus envelope glycoproteins mediated fusion by the HPIV-3 HRC-derived fusion inhibitors HPIV-P2 (○), the monomeric cholesterol-tagged fusion inhibitor HPIV-P3 (•), the dimeric fusion inhibitor HPIV-P5 (□), and the dimeric cholesterol-tagged inhibitor HPIV-P4 (▪).

<p>The percent inhibition of fusion (compared to control cells not treated with peptide) is shown as a function of the (log-scale) concentration of peptide. The values are means (±SD) of the results from three experiments.</p

Inhibition of HIV infectivity by the fusion inhibitor HIV-P2 (▪), the monomeric cholesterol-tagged inhibitor HIV-P3 (p), the dimeric fusion inhibitor HIV-P5 (•), and the dimeric cholesterol-tagged inhibitor HIV-P4 (⧫).

<p>The efficiency of virus infection is shown as relative luciferase units (RLU) as a function of the (log-scale) concentration of peptide.</p

In vivo efficacy of the dimeric cholesterol-tagged peptide.

<p>HPIV-P4 (•) was given intraperitoneally to groups of 5 hamsters concurrently with live NiV infection. Injections of the inhibitor were then repeated every day for up to 10 days post infection. Control animals were injected with vehicle alone (untreated, □) or with peptide without NiV infection (mock infected, Δ). Treatment with the dimeric cholesterol tagged peptide led to a statistically significant increase of survival compared to non treated infected animals (Chi² test = **P value = 0.008).</p

Inhibition of type 3 HPIV envelope glycoproteins mediated fusion by the HRC-derived fusion inhibitors HPIV-P2 (○), the monomeric cholesterol-tagged fusion inhibitor HPIV-P3 (•), the dimeric fusion inhibitor HPIV-P5 (□), and the dimeric cholesterol-tagged inhibitor HPIV-P4 (▪).

<p>The percent inhibition of fusion (compared to control cells not treated with peptide) is shown as a function of the (log-scale) concentration of peptide. The values are means (±SD) of the results from three experiments.</p

Sequence of the peptides used in this study.

<p>Sequence of the peptides used in this study.</p