Bio-nano scale modifications of melittin for improving therapeutic efficacy

Spotlight on HIV-derived TAT peptide as a molecular shuttle in drug delivery

HIV-derived TAT peptide, with a high penetration rate into cells and its nonimmunogenic and minimally toxic nature, is an attractive tool for enhancing the biodistribution of drugs and their systemic administration. Despite the presence of numerous promising preclinical investigations illustrating its capability to specifically target distinct tissues and deliver a diverse range of pharmacological agents, the efficacy of various clinical trials incorporating TAT has been impeded by several considerable obstacles. Hence, there is much need for an in-depth investigation concerning the application of TAT in drug delivery mechanisms. In this review, we have elucidated the structure of TAT and its utility in the proficient delivery of various types of bioactive molecules.

Therapeutic Potential and Mechanisms of Bee Venom Therapy: A Comprehensive Review of Apitoxin Applications and Safety Enhancement Strategies

Apitoxin therapy (BVT-bee venom therapy) is an emerging complementary treatment utilizing bee venom for various medical conditions. This review explores the potential and therapeutic mechanisms of bee venom, focusing on its chemical composition and the methods for its extraction and purification to enhance safety while maintaining bioactivity. Bee venom contains amphipathic peptides such as melittin and apamin, enzymes like phospholipase A2, and bioamines including histamine and catecholamines, contributing to its pleiotropic effects. The therapeutic applications of bee venom span anti-inflammatory, analgesic, antimicrobial, antiviral, neuroprotective, anti-arthritic, and anti-cancer activities. Clinical and laboratory studies have demonstrated its efficacy in treating chronic and autoimmune diseases, pain management, and improving quality of life. The immunogenic properties of bee venom necessitate ongoing research to mitigate allergic reactions, ensuring its safe and effective use in medical practice. This review summarizes the current state of research on bee venom therapy, highlighting its potential benefits and future research directions.

A Critical Review of Short Antimicrobial Peptides from Scorpion Venoms, Their Physicochemical Attributes, and Potential for the Development of New Drugs

Scorpion venoms have proven to be excellent sources of antimicrobial agents. However, although many of them have been functionally characterized, they remain underutilized as pharmacological agents, despite their evident therapeutic potential. In this review, we discuss the physicochemical properties of short scorpion venom antimicrobial peptides (ssAMPs). Being generally short (13-25 aa) and amidated, their proven antimicrobial activity is generally explained by parameters such as their net charge, the hydrophobic moment, or the degree of helicity. However, for a complete understanding of their biological activities, also considering the properties of the target membranes is of great relevance. Here, with an extensive analysis of the physicochemical, structural, and thermodynamic parameters associated with these biomolecules, we propose a theoretical framework for the rational design of new antimicrobial drugs. Through a comparison of these physicochemical properties with the bioactivity of ssAMPs in pathogenic bacteria such as Staphylococcus aureus or Acinetobacter baumannii, it is evident that in addition to the net charge, the hydrophobic moment, electrostatic energy, or intrinsic flexibility are determining parameters to understand their performance. Although the correlation between these parameters is very complex, the consensus of our analysis suggests that there is a delicate balance between them and that modifying one affects the rest. Understanding the contribution of lipid composition to their bioactivities is also underestimated, which suggests that for each peptide, there is a physiological context to consider for the rational design of new drugs.

Immunomodulatory activities and biomedical applications of melittin and its recent advances

Melittin (MLT), a peptide containing 26 amino acids, is a key constituent of bee venom. It comprises ∼40%-60% of the venom's dry weight and is the main pricing index for bee venom, being the causative factor of pain. The unique properties of MLT extracted from bee venom have made it a very valuable active ingredient in the pharmaceutical industry as this cationic and amphipathic peptide has propitious effects on human health in diverse biological processes. It has the ability to strongly impact the membranes of cells and display hemolytic activity with anticancer characteristics. However, the clinical application of MLT has been limited by its severe hemolytic activity, which poses a challenge for therapeutic use. By employing more efficient mechanisms, such as modifying the MLT sequence, genetic engineering, and nano-delivery systems, it is anticipated that the limitations posed by MLT can be overcome, thereby enabling its wider application in therapeutic contexts. This review has outlined recent advancements in MLT's nano-delivery systems and genetically engineered cells expressing MLT and provided an overview of where the MLTMLT's platforms are and where they will go in the future with the challenges ahead. The focus is on exploring how these approaches can overcome the limitations associated with MLT's hemolytic activity and improve its selectivity and efficacy in targeting cancer cells. These advancements hold promise for the creation of innovative and enhanced therapeutic approaches based on MLT for the treatment of cancer.

The Synthetic Antimicrobial Peptide Derived From Melittin Displays Low Toxicity and Anti-infectious Properties

The low stability and nonspecific toxicity are the main limiting factors for the clinical applications of melittin (MLT). This study aimed to design and synthesize new analogs of MLT to increase stability, reduce toxicity, and retain their antimicrobial properties against bacterial pathogens. At first, peptide analogs were designed computationally by inducing single mutations in MLT peptides and evaluating their physicochemical properties. The stability of the analogs with the highest scores was determined by Gromacs software. In vitro assays were performed to examine the antimicrobial activity and toxicity of the selected analogs. Two peptide analogs, M1 and M2, were selected based on the SVM score in cell PPD. The M1 analog was created by replacing alanine with leucine on the 15th. The M2 analog was designed by substituting alanine with leucine and isoleucine with arginine at the 15th and 17th positions. According to the Gromacs results, the M2 peptide indicated more stability. RMSD and RMSF results showed no undesirable fluctuations during the 200 ns MD simulation. The MIC and MBC values for the M1 peptide were calculated in a range of 8-128 μg/ml, while the M2 peptide limited the bacterial growth to 32-128 μg/mL. Both peptides indicated less toxicity than natural MLT, based on MTT assay results. The hemolytic activity of the M1 analog was more than M2 at 16 μg/mL concentration. M1 peptide displayed the highest selectivity index against S. aureus and A. baumannii, which were approximately 5.27-fold improvements compared to MLT. In conclusion, we introduced two analogs of MLT with low toxicity, low hemolytic activity, and higher stability, along with retaining antimicrobial properties against gram-negative and positive bacteria.

Rational design of an anti-cancer peptide inhibiting CD147 / Cyp A interaction

The CD147 / Cyp A interaction is a critical pathway in cancer types and an essential factor in entering the COVID-19 virus into the host cell. Melittin acts as an inhibitory peptide in cancer types by blocking the CD147/ Cyp A interaction. The clinical application of Melittin is limited due to weak penetration into cancer cells. TAT is an arginine-rich peptide with high penetration ability into cells widely used in drug delivery systems. This study aimed to design a hybrid peptide derived from Melittin and TAT to inhibit CD147 /Cyp A interaction. An amino acid region with high anti-cancer activity in Melittin was selected based on the physicochemical properties. Based on the results, a truncated Melittin peptide with 15 amino acids by the GGGS linker was fused to a TAT peptide (nine amino acids) to increase the penetration rate into the cell. A new hybrid peptide analog(TM) was selected by replacing the glycine with serine based on random point mutation. Docking results indicated that the TM peptide acts as an inhibitory peptide with high binding energy when interacting with CD147 and the CypA proteins. RMSD and RMSF results confirmed the high stability of the TM peptide in interaction with CD147. Also, the coarse-grained simulation showed the penetration potential of TM peptide into the DOPS-DOPC model membrane. Our findings indicated that the designed multifunctional peptide could be an attractive therapeutic candidate to halter tumor types and COVID-19 infection.