Therapeutic Effect of Bee Venom and Melittin on Skin Infection Caused by Streptococcus pyogenes

Dimerization and lysine substitution of melittin have differing effects on bacteria

Introduction

Melittin is a potent antimicrobial peptide from bee venom that is effective against both Gram-positive and Gram-negative bacteria. However, it is extremely toxic to mammalian cells and, as yet, has no clinical use. Modifications to its amino acid sequence, cyclization, truncation, and dimerization have been attempted in order to reduce its toxicity whilst maintaining its antimicrobial activity.

Methods

In this study, we targeted the three lysine residues present in melittin and substituted them with lysine homologs containing shorter side chains (ornithine, Orn, diaminobutyric acid, Dab, and diaminopropanoic acid, Dap) and made both parallel and antiparallel melittin dimers to observe how lysine substitution and dimerization affects its activity and toxicity. The antibacterial activity of melittin and its analogs was tested against S. aureus (Gram-positive bacteria) and E. coli (Gram-negative bacteria), and cytotoxicity was tested against the mammalian cell lines HEK293 and H4IIE.

Results

Overall, dimerization and lysine substitution exhibited improved antimicrobial activity toward E. coli and limited improvement toward S. aureus. However, mammalian cell toxicity was only marginally reduced compared to native melittin. Interestingly, the parallel dimer was found to be marginally more active than the antiparallel dimer, indicating orientation maybe important for activity, although both dimers were less effective than the native and Lys-analog peptides toward S. aureus. Of the Lys substitutions, Dab and Dap improved melittin's activity toward E. coli.

Discussion

Dimerization and Lys substitution of melittin improved the antimicrobial activity toward Gram-negative bacteria but did not significantly improve its activity toward Gram-positive bacteria. Some analogs also displayed reduced toxicity toward HEK293 and H4IIE cells but overall remained toxic at bactericidal concentrations. Our data indicates that although highly antibacterial, melittin's toxicity is the major drawback in its potential use.

Being Stung Once or Twice by Bees (Apis mellifera L.) Slightly Disturbed the Serum Metabolome of SD Rats to a Similar Extent

In most cases, the number of honeybee stings received by the body is generally small, but honeybee stings can still cause serious allergic reactions. This study fully simulated bee stings under natural conditions and used 1H Nuclear Magnetic Resonance (1H NMR) to analyze the changes in the serum metabolome of Sprague-Dawley (SD) rats stung once or twice by honeybees to verify the impact of this mild sting on the body and its underlying mechanism. The differentially abundant metabolites between the blank control rats and the rats stung by honeybees included four amino acids (aspartate, glutamate, glutamine, and valine) and four organic acids (ascorbic acid, lactate, malate, and pyruvate). There was no separation between the sting groups, indicating that the impact of stinging once or twice on the serum metabolome was similar. Using the Principal Component Discriminant Analysis ( PCA-DA) and Variable Importance in Projection (VIP) methods, glucose, lactate, and pyruvate were identified to help distinguish between sting groups and non-sting groups. Metabolic pathway analysis revealed that four metabolic pathways, namely, the tricarboxylic acid cycle, pyruvate metabolism, glutamate metabolism, and alanine, aspartate, and glutamate metabolism, were significantly affected by bee stings. The above results can provide a theoretical basis for future epidemiological studies of bee stings and medical treatment of patients stung by honeybees.

Highly in vitro anti-cancer activity of melittin-loaded niosomes on non-small cell lung cancer cells

BACKGROUND

Development of promising medicines from natural sources, specially venom, is of highly necessitated to combat against life-threatening cancers. Non-small cell lung cancer (NSCLC) has a significant percentage of mortalities. Melittin, from bee venom, is a potent anticancer peptide but its toxicity has limited its therapeutic applications. Accordingly, this study aims to synthesize niosomes with suitable stability and capacity for carrying melittin as a drug. Additionally, it seeks to evaluate the anti-cancer activity of melittin-loaded niosomes on non-small cell lung cancer.

METHODS

The niosome was prepared by thin film hydration method. Cytotoxicity and apoptosis were assessed on A549, Calu-3, and MRC5 cells. Real-time PCR was used to determine expression of apoptotic and pro-apoptotic Bax, Bcl2, and Casp3 genes. Immunocytochemistry (ICC) was also used to confirm expression of the abovementioned genes. Furthermore, wound healing assay was performed to compare inhibition effects of melittin-loaded niosomes with free melittin on migration of cancer cells.

RESULTS

IC50 values of melittin-loaded niosomes for A549, Calu-3, and MRC5 cells were respectively 0.69 μg/mL, 1.02 μg/mL, and 2.56 μg/mL after 72 h. Expression level of Bax and Casp3 increased '10 and 8' and '9 and 10.5' fold in A549 and Calu-3, whereas Bcl2 gene expression decreased 0.19 and 0.18 fold in the mentioned cell lines. The cell migration inhibited by melittin-loaded niosomes.

CONCLUSIONS

Melittin-loaded niosomes had more anti-cancer effects and less toxicity on normal cells than free melittin. Furthermore, it induced apoptosis and inhibited cancer cells migration. Our results showed that melittin-loaded niosomes may be a drug lead and it has the potential to be future developed for lung cancer treatment.

Natural agents as wound-healing promoters

The management of acute and chronic wounds resulting from diverse injuries poses a significant challenge to clinical practices and healthcare providers. Wound healing is a complex biological process driven by a natural physiological response. This process involves four distinct phases, namely hemostasis, inflammation, proliferation, and remodeling. Despite numerous investigations on wound healing and wound dressing materials, complications still persist, necessitating more efficacious therapies. Wound-healing materials can be categorized into natural and synthetic groups. The current study aims to provide a comprehensive review of highly active natural animal and herbal agents as wound-healing promoters. To this end, we present an overview of in vitro, in vivo, and clinical studies that led to the discovery of potential therapeutic agents for wound healing. We further elucidated the effects of natural materials on various pharmacological pathways of wound healing. The results of previous investigations suggest that natural agents hold great promise as viable and accessible products for the treatment of diverse wound types.

Melittin acupoint injection in attenuating bone erosion in collagen-induced arthritis mice via inhibition of the RANKL/NF-κB signaling pathway

Background

Rheumatoid arthritis (RA) is an autoimmune disease leading to chronic joint inflammation. Bone erosion is the most serious pathological condition of RA and the main cause of joint deformities and disability. Melittin acupoint injection (MAI) is an effective traditional Chinese medicine (TCM) method for RA treatment. This study aimed to investigate the effect of MAI on RA bone erosion and to elucidate the underlying mechanism.

Methods

A collagen-induced arthritis (CIA) mouse model was established as the experimental subject. MAI was administrated once every other day for 28 days to mice with CIA. The effects of MAI on joint diseases were assessed by body weight, arthritis index (AI) score, swollen joint count (SJC) score, and hind paw thickness. Ankle radiological changes were captured by micro-computed tomography (micro-CT) and histological changes were observed by pathological staining. Organ histological changes, spleen index, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatinine (Crea) levels of serum were tested to evaluate the toxicity of MAI. Cytokine expression levels were confirmed by enzyme-linked immunosorbent assay (ELISA) to evaluate the immunity of CIA mice.

Results

MAI administration markedly improved the clinical signs of CIA in mice, including hind paw thickness, AI, and the number of swollen paw joints (most of them P<0.05 or even <0.01). According to histopathological analysis, MAI ameliorated inflammatory cell infiltration, synovial hyperplasia, pannus formation, and bone erosion (all P<0.01). Micro-CT and tartrate-resistant acid phosphatase (TRAP) staining (P<0.01) also revealed that MAI could relieve bone erosion via reducing the formation of osteoclasts. Not only could MAI relieve the immunological boost [P<0.05 for the high-dose MAI (HM) group], but also it had no liver or kidney side effects (P>0.05). In addition, it decreased the serum levels of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α) and increased the serum levels of IL-4 and IL-10 (the majority of P<0.05 or even <0.01). Transcriptome sequencing results indicated that MAI affected the expression of osteoclast differentiation pathway genes, which was connected with the receptor activator of the nuclear factor κB ligand/nuclear factor kappa B (RANKL/NF-κB) pathway.

Conclusions

Based on our findings, MAI could suppress joint inflammation and inhibit RANKL/NF-κB-mediated osteoclast differentiation to rescue bone erosion in CIA mice, suggesting that MAI can be a potentially therapeutic substance for RA.

Innovative multiple nanoemulsion (W/O/W) based on Chilean honeybee pollen improves their permeability, antioxidant and antibacterial activity

Beehive derivatives, including honeybee pollen (HBP), have been extensively studied for their beneficial health properties and potential therapeutic use. Its high polyphenol content gives it excellent antioxidant and antibacterial properties. Today its use is limited due to poor organoleptic properties, low solubility, stability, and permeability under physiological conditions. A novel edible multiple W/O/W nanoemulsion (BP-MNE) to encapsulate the HBP extract was designed and optimized to overcome these limitations. The new BP-MNE has a small size (∼100 nm), a zeta potential greater than +30 mV, and efficiently encapsulated phenolic compounds (∼82%). BP-MNE stability was measured under simulated physiological conditions and storage conditions (4 months); in both cases, stability was promoted. The formulation's antioxidant and antibacterial (Streptococcus pyogenes) activity was analyzed, obtaining a higher effect than the non-encapsulated compounds in both cases. In vitro permeability was tested, observing a high permeability of the phenolic compounds when they are nanoencapsulated. With these results, we propose our BP-MNE as an innovative solution to encapsulate complex matrices, such as HBP extract, as a platform to develop functional foods.

Strategies for Improving Transdermal Administration: New Approaches to Controlled Drug Release

In this work, we aim to address several strategies to improve transdermal drug delivery, such as iontophoresis, sonophoresis, electroporation and micron. We also propose a review of some transdermal patches and their applications in medicine. TDDs (transdermal patches with delayed active substances) are multilayered pharmaceutical preparations that may contain one or more active substances, of which, systemic absorption is achieved through intact skin. The paper also presents new approaches to the controlled release of drugs: niosomes, microemulsions, transfersomes, ethosomes, but also hybrid approaches nanoemulsions and microns. The novelty of this review lies in the presentation of strategies to improve the transdermal administration of drugs, combined with their applications in medicine, in light of pharmaceutical technological developments.