Chimeric peptide-mediated siRNA transduction to inhibit HIV-1 infection

The Role of Peptides in Combatting HIV Infection: Applications and Insights

Peptide-based inhibitors represent a promising approach for the treatment of HIV-1, offering a range of potential advantages, including specificity, low toxicity, and the ability to target various stages of the viral lifecycle. This review outlines the current state of research on peptide-based anti-HIV therapies, highlighting key advancements and identifying future research directions. Over the past few years, there has been significant progress in developing synthetic peptide-based drugs that target various stages of the viral life cycle, including entry and replication. These approaches aim to create effective anti-HIV therapies. Additionally, peptides have proven valuable in the development of anti-HIV vaccines. In the quest for effective HIV vaccines, discovering potent antigens and designing suitable vaccine strategies are crucial for overcoming challenges such as low immunogenicity, safety concerns, and increased viral load. Innovative strategies for vaccine development through peptide research are, therefore, a key focus area for achieving effective HIV prevention. This review aims to explore the strategies for designing peptides with anti-HIV activity and to highlight their role in advancing both therapeutic and preventive measures against HIV.

Application of Cell Penetrating Peptides as a Promising Drug Carrier to Combat Viral Infections

Novel effective drugs or therapeutic vaccines have been already developed to eradicate viral infections. Some non-viral carriers have been used for effective drug delivery to a target cell or tissue. Among them, cell penetrating peptides (CPPs) attracted a special interest to enhance drug delivery into the cells with low toxicity. They were also applied to transfer peptide/protein-based and nucleic acids-based therapeutic vaccines against viral infections. CPPs-conjugated drugs or vaccines were investigated in several viral infections including poliovirus, Ebola, coronavirus, herpes simplex virus, human immunodeficiency virus, hepatitis B virus, hepatitis C virus, Japanese encephalitis virus, and influenza A virus. Some studies showed that the uptake of CPPs or CPPs-conjugated drugs can be performed through both non-endocytic and endocytic pathways. Despite high potential of CPPs for cargo delivery, there are some serious drawbacks such as non-tissue-specificity, instability, and suboptimal pharmacokinetics features that limit their clinical applications. At present, some solutions are utilized to improve the CPPs properties such as conjugation of CPPs with targeting moieties, the use of fusogenic lipids, generation of the proton sponge effect, etc. Up to now, no CPP or composition containing CPPs has been approved by the Food and Drug Administration (FDA) due to the lack of sufficient in vivo studies on stability, immunological assays, toxicity, and endosomal escape of CPPs. In this review, we briefly describe the properties, uptake mechanisms, advantages and disadvantages, and improvement of intracellular delivery, and bioavailability of cell penetrating peptides. Moreover, we focus on their application as an effective drug carrier to combat viral infections.

Antiviral Peptide-Based Conjugates: State of the Art and Future Perspectives

Infectious diseases caused by microbial pathogens (bacteria, virus, fungi, parasites) claim millions of deaths per year worldwide and have become a serious challenge to global human health in our century. Viral infections are particularly notable in this regard, not only because humankind is facing some of the deadliest viral pandemics in recent history, but also because the arsenal of drugs to combat the high levels of mutation, and hence the antigenic variability of (mostly RNA) viruses, is disturbingly scarce. Therefore, the search for new antivirals able to successfully fight infection with minimal or no adverse effects on the host is a pressing task. Traditionally, antiviral therapies have relied on relatively small-sized drugs acting as proteases, polymerases, integrase inhibitors, etc. In recent decades, novel approaches involving targeted delivery such as that achieved by peptide-drug conjugates (PDCs) have gained attention as alternative (pro)drugs for tackling viral diseases. Antiviral PDC therapeutics typically involve one or more small drug molecules conjugated to a cell-penetrating peptide (CPP) carrier either directly or through a linker. Such integration of two bioactive elements into a single molecular entity is primarily aimed at achieving improved bioavailability in conditions where conventional drugs are challenged, but may also turn up novel unexpected functionalities and applications. Advances in peptide medicinal chemistry have eased the way to antiviral PDCs, but challenges remain on the way to therapeutic success. In this paper, we review current antiviral CPP-drug conjugates (antiviral PDCs), with emphasis on the types of CPP and antiviral cargo. We integrate the conjugate and the chemical approaches most often applied to combine both entities. Additionally, we comment on various obstacles faced in the design of antiviral PDCs and on the future outlooks for this class of antiviral therapeutics.

Potential of cell-penetrating peptides (CPPs) in delivery of antiviral therapeutics and vaccines

Viral infections are a great threat to human health. Currently, there are no effective vaccines and antiviral drugs against the majority of viral diseases, suggesting the need to develop novel and effective antiviral agents. Since the intracellular delivery of antiviral agents, particularly the impermeable molecules, such as peptides, proteins, and nucleic acids, are essential to exert their therapeutic effects, using a delivery system is highly required. Among various delivery systems, cell-penetrating peptides (CPPs), a group of short peptides with the unique ability of crossing cell membrane, offer great potential for the intracellular delivery of various biologically active cargoes. The results of numerous in vitro and in vivo studies with CPP conjugates demonstrate their promise as therapeutic agents in various medical fields including antiviral therapy. The CPP-mediated delivery of various antiviral agents including peptides, proteins, nucleic acids, and nanocarriers have been associated with therapeutic efficacy both in vitro and in vivo. This review describes various aspects of viruses including their biology, pathogenesis, and therapy and briefly discusses the concept of CPP and its potential in drug delivery. Particularly, it will highlight a variety of CPP applications in the management of viral infections.

Design of Peptidomimetic Functionalized Cholesterol Based Lipid Nanoparticles for Efficient Delivery of Therapeutic Nucleic Acids

Lipid nanoparticles (LNP) are the most potent carriers for the delivery of nucleic acid-based therapeutics. The first FDA approved a short interfering RNA (siRNA) drug that uses a cationic LNP system for the delivery of siRNA against human transthyretin (hTTR). However, preparation of such LNP involves tedious multi-step synthesis with relatively low yields. In the present study, we synthesized cationic peptidomimetic functionalized cholesterol (denote Chorn) in straightforward chemical approaches with high yield. When formulated with helper lipids, Chorn LNPs complexed with siRNA to form nanoparticles with an average diameter of 150 nm to 200 nm. Chorn LNP mediated transfection of a green fluorescence protein (GFP) expressing plasmid resulted in 60% GFP positive cells. Moreover, Chorn LNP delivered siRNA against polo-like kinase 1 (Plk1), a disease related gene in cancer cells and efficiently suppressed the expression of the gene, resulting in significant morphological changes in the cell nuclei. Our data suggested that cholesterol based cationic LNP, prepared through a robust chemical strategy, may provide a promising siRNA delivery system.

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

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.

Cell-penetrating peptides and their utility in genome function modifications (Review)

For almost 30 years, studies have confirmed the effectiveness of cell-penetrating peptides (CPPs) in the facilitation of the intracellular delivery of various cargo molecules, including RNA, DNA, plasmids, proteins or nanoparticles, under in vitro and in vivo conditions. The cellular uptake of CPPs occurs via energy-dependent, as well as -independent mechanisms. In this relatively new direction of research, studies have attempted to introduce genome modification systems into cells by CPPs. Cellular uptake of CPPs carrying either covalently bound or electrostatically conjugated cargo, has several advantages over viral delivery systems, as it does not lead to any significant cytotoxicity or immunogenicity, and simultaneously it is more efficient than other non-viral systems. So far, CPPs have been successfully used to introduce Cre recombinase, zinc finger nucleases, transcription activator-like effector nucleases and clustered regularly interspaced short palindromic repeats systems into cells. The present article systematically reviewed the information obtained from studies on CPPs and assessed their utility with regard to their effectiveness and safety of use.

Synthetic Nucleic Acid Analogues in Gene Therapy: An Update for Peptide-Oligonucleotide Conjugates

The main objective of this work is to provide an update on synthetic nucleic acid analogues and nanoassemblies as tools in gene therapy. In particular, the synthesis and properties of peptide-oligonucleotide conjugates (POCs), which have high potential in research and as therapeutics, are described in detail. The exploration of POCs has already led to fruitful results in the treatment of neurological diseases, lung disorders, cancer, leukemia, viral, and bacterial infections. However, delivery and in vivo stability are the major barriers to the clinical application of POCs and other analogues that still have to be overcome. This review summarizes recent achievements in the delivery and in vivo administration of synthetic nucleic acid analogues, focusing on POCs, and compares their efficiency.