Therapeutic effects of bee venom and its major component, melittin, on atopic dermatitis in vivo and in vitro

Harnessing bee venom for inflammatory diseases management: from traditional medicine to nanotechnology

This review investigates the anti-inflammatory potential of bee venom, a natural compound comprising peptides, enzymes, biogenic amines other bioactive amines, and other bioactive components. It aims to elucidate how bee venom mitigates inflammatory responses caused by tissue injury, infections, and trauma. This study also explores the advancements in nanotechnology to enhance bee venom's therapeutic effects. A systematic review of studies from Google Scholar and PubMed, up to 2025, was conducted. Both in vitro and in vivo research focusing on bee venom's effects on proinflammatory mediators were analyzed. Specific attention was given to its molecular mechanisms, therapeutic impact on inflammatory conditions, and the role of nanotechnology in improving drug delivery and stability. Bee venom and its components, including melittin, apamin, and phospholipase A2 demonstrate robust anti-inflammatory properties by inhibiting key proinflammatory mediators. These effects have been observed in the treatment of chronic inflammatory conditions such as rheumatoid arthritis and skin disorders. Studies show bee venom's capacity to reduce excessive inflammatory responses effectively. Moreover, incorporating nanotechnology significantly enhances its therapeutic benefits by improving delivery, stability, and bioavailability, paving the way for advanced applications. Bee venom offers a natural, powerful approach to combating the inflammation and related chromic disorders. Its ability to regulate inflammatory pathways is promising for therapeutic use. The integration of nanotechnology further amplifies its potential, providing innovative solutions for efficient and targeted treatments. This study also highlights the need for more clinical trials to establish bee venom as a mainstream therapeutic agent in modern medicine.

Ameliorative Effects of Escin on Inflammation via Glucocorticoid Receptor (GR) in Atopic Dermatitis (AD) Mouse Model

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease characterized by intense itching. Escin, derived from Aesculus hippocastanum, has several pharmacological functions, including anti-inflammatory and anti-viral effects, and exhibits glucocorticoid-like actions in inflammatory responses. However, its impact on AD has not been extensively studied. We investigated the anti-inflammatory effects of escin on AD and elucidate its underlying mechanism of actions in the dermatophagoides farinae extract (DFE)-induced AD mouse model. The AD-induced group treated with escin showed a significant reduction in immunoglobulin E (IgE) levels, ear thickness, epidermal thickness, and mast cell infiltration compared to the AD group. Additionally, escin significantly reduced the dermatitis score and the sizes of the spleen and lymph nodes. Notably, escin inhibited the reduction of filaggrin expression induced by DFE, while suppressing the upregulation of thymic stromal lymphopoietin (TSLP), interleukin (IL)-4, IL-13, IL-1β, and tumor necrosis factor (TNF)-α. Escin also significantly suppressed DFE-induced NF-κB expression. Interestingly, pre-treatment with RU486, a glucocorticoid receptor (GR) antagonist, attenuated the therapeutic effects of escin. In line with these findings, escin modulated the IFN-γ/TNF-α-mediated changes in TSLP and filaggrin expression in HaCaT keratinocyte cells. Furthermore, escin inhibited the lipopolysaccharide (LPS)-induced overproduction of nitric oxide (NO), protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and mRNA expression of IL-6 and IL-1β in RAW 264.7 cells. These results indicate that escin may offer therapeutic potential in treating AD through the GR.

A review on NLRP3 inflammasome modulation by animal venom proteins/peptides: mechanisms and therapeutic insights

The venom peptides from terrestrial as well as aquatic species have demonstrated potential in regulating the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a sophisticated assemblage present in immune cells responsible for detecting and responding to external mediators. The NLRP3 inflammasome plays a role in several pathological conditions such as type 2 diabetes, hyperglycemia, Alzheimer's disease, obesity, autoimmune disorders, and cardiovascular disorders. Venom peptides derived from animal venoms have been discovered to selectively induce certain signalling pathways, such as the NLRP3 inflammasome, mitogen-activated protein kinase (MAPK), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Experimental evidence has demonstrated that venom peptides can regulate the expression and activation of the NLRP3 inflammasome, resulting in the secretion of pro-inflammatory cytokines including interleukin (IL)-1β and IL-18. Furthermore, these peptides have been discovered to impede the activation of the NLRP3 inflammasome, therefore diminishing inflammation and tissue injury. The functional properties of venom proteins and peptides obtained from snakes, bees, wasps, and scorpions have been thoroughly investigated, specifically targeting the NLRP3 inflammasome pathway, venom proteins and peptides have shown promise as therapeutic agents for the treatment of certain inflammatory disorders. This review discusses the pathophysiology of NLRP3 inflammasome in the onset of various diseases, role of venom as therapeutics. Further, various venom components and their role in the modulation of NLRP3 inflammasome are discoursed. A substantial number of venomous animals and their toxins are yet unexplored, and to comprehensively grasp the mechanisms of action of them and their potential as therapeutic agents, additional research is required which can lead to the development of novel therapeutics.

d-Limonene inhibits cytokines and chemokines expression by regulating NF-kappaB and STAT in HaCat cells and DNCB-induced atopic dermatitis in BALB/c mice

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by itching and redness, affecting individuals of all ages and significantly impairing their quality of life. The prevalence of AD is rising, posing serious health concern. Relief of itching is a primary treatment objective; however, steroid treatments can lead to adverse effects, including skin barrier thinning. Therefore, there is a pressing need for safer therapeutic alternatives. Limonene, a naturally occurring monocyclic monoterpene found in citrus peel oil, is widely utilized in food, cosmetics, and pharmaceuticals. Research has identified various biological activities of limonene, including antioxidative, anti-inflammatory, immunomodulatory, and antifibrotic properties. This study aims to investigate the therapeutic effects of limonene on atopic dermatitis, focusing on its anti-inflammatory potential.

METHODS

In this study, we investigated the expression levels of pro-inflammatory cytokines and chemokines, conducting histopathological analyses, and collecting physiological data from BALB/c mice with atopic-like dermatitis induced by 2,4-dinitrochlorobenzene (DNCB) and TNF-α/ IFN-γ-stimulated HaCaT cells.

RESULTS

In vitro studies indicated that limonene inhibited cytokine and chemokine expression in human keratinocytes and reduced phosphorylation in the MAPK, NF-κB, and JAK/STAT signaling pathways. In vivo, limonene mitigated DNCB-induced skin barrier damage and itching, improving physiological parameters such as trans-epidermal water loss, erythema, and ear thickness. Furthermore, it decreased the mRNA expression of pro-inflammatory cytokines.

CONCLUSION

Limonene exhibits significant anti-inflammatory effects, highlighting its therapeutic potential for treating atopic dermatitis.

Investigating the effect of a herbal cream containing rose essence in an animal model of eczema

Objective

Eczema, a common inflammatory skin condition characterized by itching and dermatitis, can significantly impact the quality of life. While conventional treatments exist, there is interest in exploring natural alternatives. This study investigates the efficacy of a rosehip extract-based cream in mitigating eczema symptoms in a mouse model.

Materials and Methods

Thirty-five mice were divided into five groups: control, dinitrochlorobenzene (DNCB)-induced eczema (model group), and treatment groups receiving placebo, betamethasone cream (positive control), or rosehip extract cream. Following topical treatment for four weeks, the animals were euthanized, and their skin was evaluated for inflammation, moisture, and thickness. Histopathological analysis was performed using hematoxylin and eosin (H&E) staining.

Results

Compared to the control group, DNCB treatment significantly increased inflammation, erythema (redness), dryness, and epidermal thickness. Notably, topical application of the rosehip extract cream significantly reduced these eczema-associated parameters, demonstrating efficacy comparable to the positive control (betamethasone cream).

Conclusion

This study suggests that a topical cream formulated with rosehip extract may be a promising therapeutic strategy for alleviating eczema symptoms. The anti-inflammatory and potentially regenerative properties of rose extract warrant further investigation for the development of natural eczema treatments.

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.

New perspective for pathomechanism and clinical applications of animal toxins: Programmed cell death

Various animal toxins pose a significant threat to human safety, necessitating urgent attention to their treatment and research. The clinical potential of programmed cell death (PCD) is widely regarded as a target for envenomation, given its crucial role in regulating physiological and pathophysiological processes. Current research on animal toxins examines their specific components in pathomechanisms and injuries, as well as their clinical applications. This review explores the relationship between various toxins and several types of PCD, such as apoptosis, necroptosis, autophagy, ferroptosis, and pyroptosis, to provide a reference for future understanding of the pathophysiology of toxins and the development of their potential clinical value.

Bee venom acupuncture and herbal medicine for hand eczema: Two case reports and an in vivo study

INTRODUCTION

Eczema and contact dermatitis are relatively common, non-life-threatening disease, but can reduce the patient's quality-of-life when it becomes chronic. This study describes two cases of bee venom acupuncture (BVA) and herbal medicine (San Wu Huangqin decoction; SWH) co-treatment for hand eczema and contact dermatitis, then confirms the effect of the combination therapy in an in vivo model of eczema.

CASE PRESENTATION

A 56-year-old female (case 1) and a 33-year-old male (case 2) presented to the clinic with symptoms of itching and erythema (case 1), and scaliness (case 2) on both hands. Both were diagnosed with hand eczema and contact dermatitis based on examination of the erythema and scaliness. They were treated with BVA and SWH for three months. The lesions were healed and had not recurred after 1 and 3 years of follow-up. A mouse study was conducted by repeated application of 2,4-dinitrochlorobenzene (DNCB) to induce eczema-like contact dermatitis in Balb/c mice. In a DNCB-induced eczema-like contact dermatitis model, BVA and SWH co-administration synergistically improved clinical symptoms seen in eczema. Also, they improved histological changes of the skin, suppressed immune cell infiltration, and decreased inflammatory cytokines and immunoglobulin E in the serum.

CONCLUSION

This study suggests BVA and SWH could be an alternative treatment for eczema and contact dermatitis.

Role of LECT2 in exacerbating atopic dermatitis: insight from in vivo and in vitro models via NF-κB signaling pathway

Leukocyte cell-derived chemotaxin 2 (LECT2) is linked to various immune diseases. Previously, we reported that serum LECT2 levels correlate with disease severity in atopic dermatitis (AD) patients. To investigate the role of LECT2 in AD and elucidate its potential mechanisms, we used LECT2 to treat an AD mouse model induced by 1-Chloro-2,4-dinitrobenzene (DNCB) in LECT2 knockout (KO) and wild-type (WT) mice, and an AD cell model using TNF-α/IFN-γ-induced HaCaT cells. Inflammatory factors and barrier proteins were analyzed by histology, immunohistochemistry, RT-qPCR, ELISA, and Western Blot. Activation of the NF-κB signaling pathway was evaluated by Western Blot and immunofluorescence. In the AD mouse model, LECT2 treatment increased epidermal and dermal thickness, mast cell infiltration, and downregulated barrier proteins. Inflammatory factors were increased in skin lesions and serum. In the AD cell model, LECT2 decreased barrier protein levels and increased inflammatory factor levels, enhancing NF-κB P65 nuclear translocation. These results indicate that LECT2 exacerbates AD-like responses by dysregulating the NF-κB signaling pathway, highlighting its potential as a therapeutic target for AD management.

Harnessing the power of bee venom for therapeutic and regenerative medical applications: an updated review

Honeybees have been helpful insects since ancient centuries, and this benefit is not limited to being a honey producer only. After the bee stings a person, pain, and swelling occur in this place, due to the effects of bee venom (BV). This is not a poison in the total sense of the word because it has many benefits, and this is due to its composition being rich in proteins, peptides, enzymes, and other types of molecules in low concentrations that show promise in the treatment of numerous diseases and conditions. BV has also demonstrated positive effects against various cancers, antimicrobial activity, and wound healing versus the human immunodeficiency virus (HIV). Even though topical BV therapy is used to varying degrees among countries, localized swelling or itching are common side effects that may occur in some patients. This review provides an in-depth analysis of the complex chemical composition of BV, highlighting the diverse range of bioactive compounds and their therapeutic applications, which extend beyond the well-known anti-inflammatory and pain-relieving effects, showcasing the versatility of BV in modern medicine. A specific search strategy was followed across various databases; Web of sciences, Scopus, Medline, and Google Scholar including in vitro and in vivo clinical studies.to outline an overview of BV composition, methods to use, preparation requirements, and Individual consumption contraindications. Furthermore, this review addresses safety concerns and emerging approaches, such as the use of nanoparticles, to mitigate adverse effects, demonstrating a balanced and holistic perspective. Importantly, the review also incorporates historical context and traditional uses, as well as a unique focus on veterinary applications, setting it apart from previous works and providing a valuable resource for researchers and practitioners in the field.

Melittin inactivates YAP/HIF-1α pathway via up-regulation of LATS2 to inhibit hypoxia-induced proliferation, glycolysis and angiogenesis in NSCLC

BACKGROUND

NSCLC is one of the most common causes of death. The hypoxia microenvironment contributes to cancer progression. The purpose was to explore the effects and mechanism of melittin on NSCLC cells in the hypoxic microenvironment.

METHODS

NSCLC cell lines (A549 and H1299) were cultured in normoxia or hypoxia conditions with or without melittin treatment. The viability of the cells was detected via MTT assay and the proliferation ability was evaluated by EdU assay. QRT-PCR was performed to evaluate GLUT1, LDHA, HK2, VEGF and LATS2 mRNA levels. Glucose transport was assessed by the 2-NBDG uptake assay. The angiogenesis was determined by the tubule formation assay. The protein expressions of GLUT1, LDHA, HK2, VEGF, LATS2, YAP, p-YAP and HIF-1α were detected via western blotting assay. The tumor formation assay was conducted to examine the roles of melittin and LATS2 in vivo.

RESULTS

Melittin inhibited hypoxia-induced cell viability, proliferation, glycolysis and angiogenesis as well as suppressed YAP binding to HIF-1α in NSCLC. Melittin inactivated the YAP/HIF-1α pathway via up-regulation of LATS2, ultimately inhibiting cancer progression of NSCLC. Moreover, melittin suppressed tumor growth via up-regulation of LATS2 in vivo.

CONCLUSION

Melittin inactivated the YAP/HIF-1α pathway via up-regulation of LATS2 to contribute to the development of NSCLC. Therefore, melittin is expected to become a potential prognostic drug for the therapy of NSCLC.

Exploring the Metabolic Effects of a Herbal Remedy of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia Extracts: Unraveling Its Therapeutic Potential as a Topical Application for Atopic Dermatitis Treatment

Our previous study demonstrated that our novel herbal remedy, a mixture of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum Cassia extracts, exhibits a therapeutic effect in 1-chloro-2,4-dinitrobenzene (DNCB)-induced mice by inhibiting the Th-2 inflammatory response upon oral administration. It also ameliorated imbalances in lipid metabolism related to the skin barrier function in keratinocytes, indicating its potential as a topical agent. This study aims to further investigate the therapeutic effects and metabolic mechanisms of its topical application. The anti-atopic effect was evaluated using dermatitis scores, histopathological analysis, and immune cell factors in DNCB-induced mice. Metabolomic profiling of serum and lesional skin was conducted to elucidate the metabolic mechanisms. The topical application significantly reduced dermatitis scores, mast cell infiltration, and serum levels of immunoglobulin E (IgE), IFN-γ, interleukin (IL)-4, IL-17, and thymic stromal lymphopoietin (TSLP), demonstrating its effectiveness in treating atopic dermatitis (AD). Serum metabolomics revealed alterations in fatty acid metabolism related to the pro-inflammatory response. In lesional skin, metabolic markers associated with oxidative stress, immune regulation, and AD symptoms were restored. This study demonstrated its potential as a topical agent in suppressing Th-2 inflammatory responses and improving metabolic abnormalities related to AD symptoms, providing crucial insights for developing natural AD treatments.

Bee Venom-Loaded Niosomes as Innovative Platforms for Cancer Treatment: Development and Therapeutical Efficacy and Safety Evaluation

Despite past efforts towards therapeutical innovation, cancer remains a highly incident and lethal disease, with current treatments lacking efficiency and leading to severe side effects. Hence, it is imperative to develop new, more efficient, and safer therapies. Bee venom has proven to have multiple and synergistic bioactivities, including antitumor effects. Nevertheless, some toxic effects have been associated with its administration. To tackle these issues, in this work, bee venom-loaded niosomes were developed, for cancer treatment. The vesicles had a small (150 nm) and homogeneous (polydispersity index of 0.162) particle size, and revealed good therapeutic efficacy in in vitro gastric, colorectal, breast, lung, and cervical cancer models (inhibitory concentrations between 12.37 ng/mL and 14.72 ng/mL). Additionally, they also revealed substantial anti-inflammatory activity (inhibitory concentration of 28.98 ng/mL), effects complementary to direct antitumor activity. Niosome safety was also assessed, both in vitro (skin, liver, and kidney cells) and ex vivo (hen's egg chorioallantoic membrane), and results showed that compound encapsulation increased its safety. Hence, small, and homogeneous bee venom-loaded niosomes were successfully developed, with substantial anticancer and anti-inflammatory effects, making them potentially promising primary or adjuvant cancer therapies. Future research should focus on evaluating the potential of the developed platform in in vivo models.

Natural Sources of Therapeutic Agents Used in Skin Conditions

Skin conditions are numerous and often have a major impact on patients' quality of life, and effective and safe treatment is very important. The conventional drugs used for skin diseases are usually corticosteroids and antimicrobial products that can induce various side effects, especially with long-term use, which is why researchers are studying alternatives, especially biologically active natural products. Three products caught our attention: bee venom (BV), due to reported experimental results showing anti-inflammatory, antibacterial, antiviral, antioxidant, antimycotic, and anticancer effects, Ficus carica (FC) due to its demonstrated antioxidant, antibacterial, and anti-inflammatory action, and finally Geranium essential oil (GEO), with proven antifungal, antibacterial, anti-inflammatory, and antioxidant effects. Following a review of the literature, we produced this paper, which presents a review of the potential therapeutic applications of the three products in combating various skin conditions and for skin care, because BV, FC, and GEO have common pharmacological actions (anti-inflammatory, antibacterial, and antioxidant). We also focused on studying the safety of the topical use of BV, FC, and GEO, and new approaches to this. This paper presents the use of these natural therapeutic agents to treat patients with conditions such as vitiligo, melasma, and melanoma, as well as their use in treating dermatological conditions in patients with diabetes.

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.

Characterization of Different Inflammatory Skin Conditions in a Mouse Model of DNCB-Induced Atopic Dermatitis

The mouse model of 2,4-dinitrochlorbenzene (DNCB)-induced human-like atopic dermatitis (hlAD) has been widely used to test novel treatment strategies and compounds. However, the study designs and methods are highly diverse, presenting different hlAD disease patterns that occur after sensitization and repeated challenge with DNCB on dorsal skin. In addition, there is a lack of information about the progression of the disease during the experiment and the achieved pheno- and endotypes, especially at the timepoint when therapeutic treatment is initiated. We here examine hlAD in a DNCB-induced BALB/cJRj model at different timepoints: (i) before starting treatment with dexamethasone, representing a standard drug control (day 12) and (ii) at the end of the experiment (day 22). Both timepoints display typical AD-associated characteristics: skin thickening, spongiosis, hyper- and parakeratosis, altered cytokine and gene expression, increased lipid mediator formation, barrier protein and antimicrobial peptide abnormalities, as well as lymphoid organ hypertrophy. Increased mast cell infiltration into the skin and elevated immunoglobulin E plasma concentrations indicate a type I allergy response. The DNCB-treated skin showed an extrinsic moderate sub-acute hlAD lesion at day 12 and an extrinsic mild sub-acute to chronic pheno- and endotype at day 22 with a dominating Th2 response. A dependency of the filaggrin formation and expression in correlation to the disease severity in the DNCB-treated skin was found. In conclusion, our study reveals a detailed classification of a hlAD at two timepoints with different inflammatory skin conditions and pheno- and endotypes, thereby providing a better understanding of the DNCB-induced hlAD model in BALB/cJRj mice.

Bee venom: apitherapy and more

Honeybees are becoming increasingly familiar to the general population due to the growing popularity of backyard and amateur beekeeping. Although bee venom produces reactions ranging from mild local irritation to life-threatening anaphylaxis, it is also used for life-saving desensitization immunotherapy in those with severe reactions to bee stings. The use of honeybee venom for immunotherapy has increased due to an enhanced interest in natural therapeutics. Recently, honeybee venom has been administered as a successful, safe, and cost-effective treatment for rheumatoid arthritis, back pain, and skin diseases. During the past two decades, studies have tested honeybee venom's efficacy for treating various skin disorders, including atopic dermatitis, wound healing, and psoriasis. We will review bee venom from multiple perspectives, including its medical applications and mechanisms for dermatological pathologies.

Bee Venom and Its Two Main Components-Melittin and Phospholipase A2-As Promising Antiviral Drug Candidates

Viruses are known to infect most types of organisms. In humans, they can cause several diseases that range from mild to severe. Although many antiviral therapies have been developed, viral infections continue to be a leading cause of morbidity and mortality worldwide. Therefore, the discovery of new and effective antiviral agents is desperately needed. Animal venoms are a rich source of bioactive molecules found in natural goods that have been used since ancient times in alternative medicine to treat a variety of human diseases. Recently, and with the onset of the COVID-19 pandemic, scientists have regained their interest in the possible use of natural products, such as bee venom (BV), as a potential antiviral agent to treat viral infections. BV is known to exert many therapeutic activities such as anti-proliferative, anti-bacterial, and anti-inflammatory effects. However, there is limited discussion of the antiviral activity of BV in the literature. Therefore, this review aims to highlight the antiviral properties of BV and its two primary constituents, melittin (MEL) and phospholipase A2 (PLA2), against a variety of enveloped and non-enveloped viruses. Finally, the innovative strategies used to reduce the toxicity of BV and its two compounds for the development of new antiviral treatments are also considered.

Effects of Magnoliae Flos on Atopic Dermatitis-Like Inflammation Evaluated via Extracellular Signal-regulated Kinase or Signal Transducers and Activators of Transcription 1/3 Signalling Pathways

Atopic dermatitis is a chronic inflammatory skin  disease. Skin is the largest organ and plays a pivotal role in protecting the body. Not only does the skin act as a physical barrier against the external environment, but it also has its own immune system. Atopic dermatitis is caused by prolonged excessive inflammatory responses that worsen under imbalanced cutaneous immune system skin conditions. Although the prevalence and burden of atopic dermatitis is increasing, the standard therapeutic agents remain unclear due to  the complicated pathophysiology of the condition. The objective of this study is to examine the use of Magnoliae flos, the dried flower bud of Magnolia biondii or  related plants. The effects and underlying mechanism of  action of aqueous extract of the buds of Magnoliae flos (MF) were evaluated. Immortalized human keratinocytes (HaCaT) stimulated with tumour necrosis factor-α and interferon-γ mixture and NC/Nga mice stimulated with 2,4-dinitrochlorobenzene were used as atopic dermatitis models, in vitro and in vivo, respectively. The effects of MF were determined by measuring the suppression of pro-inflammatory signalling pathways, such as extracellular signal-regulated kinase or signal transducers and activators of transcription 1/3 and restoring skin barrier molecules. In conclusion, MF is a potential therapeutic alternative for the treatment of atopic dermatitis through repressing inflammatory pathways.

Establishment and Characterization of Mild Atopic Dermatitis in the DNCB-Induced Mouse Model

In dermatological research, 2,4-dinitrochlorbenzene (DNCB)-induced atopic dermatitis (AD) is a standard model as it displays many disease-associated characteristics of human AD. However, the reproducibility of the model is challenging due to the lack of information regarding the methodology and the description of the phenotype and endotype of the mimicked disease. In this study, a DNCB-induced mouse model was established with a detailed procedure description and classification of the AD human-like skin type. The disease was induced with 1% DNCB in the sensitization phase and repeated applications of 0.3% and 0.5% DNCB in the challenging phase which led to a mild phenotype of AD eczema. Pathophysiological changes of the dorsal skin were measured: thickening of the epidermis and dermis, altered skin barrier proteins, increased TH1 and TH2 cytokine expression, a shift in polyunsaturated fatty acids, increased pro-resolving and inflammatory mediator formation, and dysregulated inflammation-associated gene expression. A link to type I allergy reactions was evaluated by increased mast cell infiltration into the skin accompanied by elevated IgE and histamine levels in plasma. As expected for mild AD, no systemic inflammation was observed. In conclusion, this experimental setup demonstrates many features of a mild human-like extrinsic AD in murine skin.

Revolutionizing the Use of Honeybee Products in Healthcare: A Focused Review on Using Bee Pollen as a Potential Adjunct Material for Biomaterial Functionalization

The field of biomedical engineering highly demands technological improvements to allow the successful engraftment of biomaterials requested for healing damaged host tissues, tissue regeneration, and drug delivery. Polymeric materials, particularly natural polymers, are one of the primary suitable materials employed and functionalized to enhance their biocompatibility and thus confer advantageous features after graft implantation. Incorporating bioactive substances from nature is a good technique for expanding or increasing the functionality of biomaterial scaffolds, which may additionally encourage tissue healing. Our ecosystem provides natural resources, like honeybee products, comprising a rich blend of phytochemicals with interesting bioactive properties, which, when functionally coupled with biomedical biomaterials, result in the biomaterial exhibiting anti-inflammatory, antimicrobial, and antioxidant effects. Bee pollen is a sustainable product recently discovered as a new functionalizing agent for biomaterials. This review aims to articulate the general idea of using honeybee products for biomaterial engineering, mainly focusing on describing recent literature on experimental studies on biomaterials functionalized with bee pollen. We have also described the underlying mechanism of the bioactive attributes of bee pollen and shared our perspective on how future biomedical research will benefit from the fabrication of such functionalized biomaterials.

Human umbilical cord mesenchymal stem cell treatment alleviates symptoms in an atopic dermatitis-like mouse model

BACKGROUND

Atopic dermatitis (AD) is one of the most common immune and inflammatory skin disorders, leading to insufferable itching and skin abnormalities that seriously affect life quality of patients. There are still huge unmet needs for long-term and effective disease control, despite currently available therapies. Evidenced by some preclinical and clinical studies of AD treatment with stem cells, stem cell treatment could significantly and effectively ameliorate AD symptoms.

OBJECTIVES

To elucidate underlying mechanisms of how stem cells therapy alleviates AD-like symptoms.

METHODS

An AD-like mouse model was constructed and treated with mesenchymal stem cells (MSCs) subcutaneously or subcutaneously combined with intravenously. The differentially expressed genes were sorted out from RNA sequencing results of dorsal skin and blood.

RESULTS

Two injection routes of MSCs could alleviate AD-like symptoms and pathologic changes of the skin and immune organs. RNA sequencing of dorsal skin sections and blood provided gene expression signatures for amelioration of skin defects, inflammatory and immune modulation by MSCs, as well as common AD molecular markers for the skin and blood, which may benefit for clinical diagnosis. IL-1β and its signaling pathway were specifically found to be associated with the development of AD-like dermatitis lesions. MSC treatment effectively inhibited the JAK-STAT pathway and receptors of IL-4, IL-13, IL-17, and IgE.

CONCLUSIONS

MSC therapy could regulate abnormal immune and inflammatory status in AD. Mechanistic exploration will contribute to the development of personalized AD treatment based on MSCs.

Ursolic acid ameliorates DNCB-induced atopic dermatitis-like symptoms in mice by regulating TLR4/NF-κB and Nrf2/HO-1 signaling pathways

BACKGROUND

Ursolic acid (UA) is a triterpenoid compound found in natural plants. It has been reported to have anti-inflammatory, antioxidant, and immunomodulatory properties. However, its role in atopic dermatitis (AD) is unknown. This study aimed to evaluate the therapeutic effect of UA in AD mice and explore the underlying mechanisms.

METHODS

Balb/c mice were treated with 2, 4-dinitrochlorobenzene (DNCB) to induce AD-like lesions. During modeling and medication administration, dermatitis scores and ear thickness were measured. Subsequently, histopathological changes, levels of T helper cytokines, and oxidative stress markers levels were evaluated. Immunohistochemistry staining was used to assess changes in the expression of the nuclear factor of kappa B (NF-κB) and NF erythroid 2-related factor 2 (Nrf2). Furthermore, CCK8 assay, reactive oxygen species (ROS) assay, real-time PCR, and western blotting were employed to evaluate the effects of UA on ROS levels, inflammatory mediator production, and the NF-κB and Nrf2 pathways in TNF-α/IFN-γ-stimulated HaCaT cells.

RESULTS

The results showed that UA significantly reduced dermatitis score and ear thickness, effectively inhibited skin proliferation and mast cell infiltration in AD mice, and decreased the expression level of T helper cytokines. Meanwhile, UA improved oxidative stress in AD mice by regulating lipid peroxidation and increasing the activity of antioxidant enzymes. In addition, UA inhibited ROS accumulation and chemokine secretion in TNF-α/IFN-γ-stimulated HaCaT cells. It might exert anti-dermatitis effects by inhibiting the TLR4/NF-κB pathway and activating the Nrf2/HO-1 pathway.

CONCLUSION

Taken together, our results suggest that UA may have potential therapeutic effects on AD and could be further studied as a promising drug for AD treatment.

Fulvic Acid Attenuates Atopic Dermatitis by Downregulating CCL17/22

The main pathogenic factor in atopic dermatitis (AD) is Th2 inflammation, and levels of serum CCL17 and CCL22 are related to severity in AD patients. Fulvic acid (FA) is a kind of natural humic acid with anti-inflammatory, antibacterial, and immunomodulatory effects. Our experiments demonstrated the therapeutic effect of FA on AD mice and revealed some potential mechanisms. FA was shown to reduce TARC/CCL17 and MDC/CCL22 expression in HaCaT cells stimulated by TNF-α and IFN-γ. The inhibitors showed that FA inhibits CCL17 and CCL22 production by deactivating the p38 MAPK and JNK pathways. After 2,4-dinitrochlorobenzene (DNCB) induction in mice with atopic dermatitis, FA effectively reduced the symptoms and serum levels of CCL17 and CCL22. In conclusion, topical FA attenuated AD via downregulation of CCL17 and CCL22, via inhibition of P38 MAPK and JNK phosphorylation, and FA is a potential therapeutic agent for AD.

Anti-inflammatory effect and metabolic mechanism of BS012, a mixture of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia extracts, on atopic dermatitis in vivo and in vitro

BACKGROUND

Atopic dermatitis (AD) is a chronic, relapsing skin disease accompanied by itchy and dry skin. AD is caused by complex interactions between innate and adaptive immune response. AD treatment include glucocorticoids and immunosuppressants. However, long-term treatment can have serious side effects. Thus, an effective AD treatment with fewer side effects is required. Natural materials, including herbal medicines, have potential applications.

PURPOSE

This study evaluated the in vivo and in vitro therapeutic effects of BS012, a mixture of Asarum sieboldii, Platycodon grandiflorum, and Cinnamomum cassia extracts, on AD and investigated the underlying metabolic mechanisms.

METHODS

The anti-inflammatory effects of BS012 were assessed using a mouse model of AD induced by 1‑chloro-2,4-dinitrobenzene (DNCB) and in tumor necrosis factor-alpha/interferon-gamma (TNF-α/IFN-γ) stimulated normal human epidermal keratinocytes (NHEKs). In DNCB-induced mice, total dermatitis score, histopathological analysis, and immune cell factors were assessed to evaluate the anti-atopic activity. In TNF-α/IFN-γ-stimulated NHEKs, pro-inflammatory cytokines, chemokines, and related signaling pathways were investigated. Serum and intracellular metabolomics were performed to identify the metabolic mechanism underlying the therapeutic effects of BS012 treatment.

RESULTS

In DNCB-induced mice, BS012 showed potent anti-atopic activity, including reducing AD-like skin lesions and inhibiting the expression of Th2 cytokines and thymic stromal lymphopoietin. In TNF-α/IFN-γ-stimulated keratinocytes, BS012 dose-dependently inhibited the expression of pro-inflammatory cytokines and chemokines by blocking nuclear factor-kappa B and signal transducer and activator of transcription signaling pathways. Serum metabolic profiles of mice revealed significant changes in lipid metabolism related to inflammation in AD. Intracellular metabolome analysis revealed that BS012 treatment affected the metabolism associated with inflammation, skin barrier function, and lipid organization of the stratum corneum.

CONCLUSION

BS012 exerts anti-atopic activity by reducing the Th2-specific inflammatory response and improving skin barrier function in AD in vivo and in vitro. These effects are mainly related to the inhibition of inflammation and recovery of metabolic imbalance in lipid organization. BS012, a novel combination with strong activity in suppressing the Th2-immune response, could be a potential alternative for AD treatment. Furthermore, the metabolic mechanism in vivo and in vitro using a metabolomics approach will provide crucial information for the development of natural products for AD treatment.

Melittin-Carrying Nanoparticle Suppress T Cell-Driven Immunity in a Murine Allergic Dermatitis Model

Allergic contact dermatitis (ACD) and atopic dermatitis (AD) are the most common human skin disorders. Although corticosteroids have been widely used to treat ACD and AD, the side effects of corticosteroids encourage researchers to explore new immunoregulatory treatments. Here, an immunomodulatory approach based on lipid nanoparticles carrying α-helical configurational melittin (α-melittin-NP) is developed to overcome T cell-mediated inflammatory reactions in an oxazolone (OXA)-induced contact hypersensitivity mouse model and OXA-induced AD-like mouse model. Intradermal injection of low-dose α-melittin-NPs prevents the skin damage caused by melittin administration alone and efficiently targeted lymph nodes. Importantly, melittin and α-melittin-NPs restrain RelB activity in dendritic cells (DCs) and further suppresses dendritic cell activation and maturation in lymph nodes. Furthermore, low-dose α-melittin-NPs leads to relief of antigen recognition-induced effector T cell arrest in the dermis and inhibited allergen-specific T cell proliferation and activation. Significantly, this approach successfully controls Th1-type cytokine release in the ACD model and restricts Th2-type cytokine and IgE release in the AD-like model. Overall, intradermal delivery of low-dose α-melittin-NPs efficiently elicits immunosuppression against T cell-mediated immune reactions, providing a promising therapeutic strategy for treating skin disorders not restricted to the lesion region.

Inhibitory Effect of Bisdemethoxycurcumin on DNCB-Induced Atopic Dermatitis in Mice

Atopic dermatitis (AD) is a common chronic inflammatory skin disease. Bisdemethoxycurcumin (BDMC) is an ingredient from the rhizome of the traditional Chinese herbal medicine turmeric. BDMC has been reported to have important pharmacological properties, such as anti-inflammatory, antioxidant, antitumor and antiproliferative activities. However, its effect on atopic dermatitis has not been reported. The purpose of our study was to demonstrate the effectiveness of BDMC on TNF-α/IFNγ-stimulated HaCaT cells and on 2,4-dinitrochlorobenzene (DNCB)-induced AD mice. Our studies showed in vitro that BDMC was able to significantly inhibit the mRNA expression of chemokines and cytokines in TNF-α/IFN-γ-stimulated HaCaT cells and alleviate their inflammatory response. Our studies found in vivo that BDMC was able to significantly improve the symptoms of DNCB-induced AD skin lesions, decrease the number of scratches, ear thickness, and spleen index, improve inflammatory cells and mast cell infiltration and decrease skin thickness. Moreover, it was also able to inhibit the mRNA expression levels of chemokines and inflammatory cytokines and the activation of the MAPK and NF-κB signaling pathways. Thus, the results indicated that BDMC can improve atopic dermatitis in mice and that further clinical studies are warranted on its treatment of AD.

Pharmacological effects and mechanisms of bee venom and its main components: Recent progress and perspective

Bee venom (BV), a type of defensive venom, has been confirmed to have favorable activities, such as anti-tumor, neuroprotective, anti-inflammatory, analgesic, anti-infectivity effects, etc. This study reviewed the recent progress on the pharmacological effects and mechanisms of BV and its main components against cancer, neurological disorders, inflammatory diseases, pain, microbial diseases, liver, kidney, lung and muscle injury, and other diseases in literature during the years 2018-2021. The related target proteins of BV and its main components against the diseases include Akt, mTOR, JNK, Wnt-5α, HIF-1α, NF-κB, JAK2, Nrf2, BDNF, Smad2/3, AMPK, and so on, which are referring to PI3K/Akt/mTOR, MAPK, Wnt/β-catenin, HIF-1α, NF-κB, JAK/STAT, Nrf2/HO-1, TrkB/CREB/BDNF, TGF-β/Smad2/3, and AMPK signaling pathways, etc. Further, with the reported targets, the potential effects and mechanisms on diseases were bioinformatically predicted via Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, disease ontology semantic and enrichment (DOSE) and protein-protein interaction (PPI) analyses. This review provides new insights into the therapeutic effects and mechanisms of BV and its main components on diseases.

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

Streptococcus pyogenes (S. pyogenes) bacteria cause almost all primary skin infections in humans. Bee venom (BV) and melittin (Mel) have multiple effects, including antibacterial and anti-inflammatory activities. This study aims to demonstrate their effects on bacterial mouse skin infection using S. pyogenes. The dorsal skin was tape-stripped, then S. pyogenes was topically applied. BV or Mel were topically applied to the lesion. The tissues were stained with hematoxylin and eosin, while immunohistochemical staining was performed with anti-neutrophil. S. pyogenes-infected skin revealed increased epidermal and dermal layers, but it was reduced in the BV and Mel groups. Finding increased neutrophils in the mice infected with S. pyogenes, but the BV and Mel mice showed decreased expression. These results suggest that BV and Mel treatments could reduce the inflammatory reactions and help improve lesions induced by S. pyogenes skin infection. This study provides additional assessment of the potential therapeutic effects of BV and Mel in managing skin infection caused by S. pyogenes, further suggesting that it could be a candidate for developing novel treatment alternative for streptococcal skin infections.

Adverse Events Associated with the Clinical Use of Bee Venom: A Review

Bee venom is used to treat various diseases but can cause a tickling sensation and anaphylaxis during clinical treatment. Adverse events (AEs) associated with bee venom may vary depending on the dosage, method, route of administration, and the country, region, and user. We summarized the AEs of bee venom used in various ways, such as by the injection of extracts, venom immunotherapy (VIT), live bee stings, or external preparations. We conducted a search in eight databases up to 28 February 2022. It took one month to set the topic and about 2 weeks to set the search terms and the search formula. We conducted a search in advance on 21 February to see if there were omissions in the search terms and whether the search formula was correct. There were no restrictions on the language or bee venom method used and diseases treated. However, natural stings that were not used for treatment were excluded. A total of 105 studies were selected, of which 67, 26, 8, and 4 were on the injection of extracts, VIT, live bee stings, and external preparation, respectively. Sixty-three studies accurately described AEs, while 42 did not report AEs. Thirty-five randomized controlled trials (RCTs) were evaluated for the risk of bias, and most of the studies had low significance. A large-scale clinical RCT that evaluates results based on objective criteria is needed. Strict criteria are needed for the reporting of AEs associated with bee venom

Modern venomics-Current insights, novel methods, and future perspectives in biological and applied animal venom research

Venoms have evolved >100 times in all major animal groups, and their components, known as toxins, have been fine-tuned over millions of years into highly effective biochemical weapons. There are many outstanding questions on the evolution of toxin arsenals, such as how venom genes originate, how venom contributes to the fitness of venomous species, and which modifications at the genomic, transcriptomic, and protein level drive their evolution. These questions have received particularly little attention outside of snakes, cone snails, spiders, and scorpions. Venom compounds have further become a source of inspiration for translational research using their diverse bioactivities for various applications. We highlight here recent advances and new strategies in modern venomics and discuss how recent technological innovations and multi-omic methods dramatically improve research on venomous animals. The study of genomes and their modifications through CRISPR and knockdown technologies will increase our understanding of how toxins evolve and which functions they have in the different ontogenetic stages during the development of venomous animals. Mass spectrometry imaging combined with spatial transcriptomics, in situ hybridization techniques, and modern computer tomography gives us further insights into the spatial distribution of toxins in the venom system and the function of the venom apparatus. All these evolutionary and biological insights contribute to more efficiently identify venom compounds, which can then be synthesized or produced in adapted expression systems to test their bioactivity. Finally, we critically discuss recent agrochemical, pharmaceutical, therapeutic, and diagnostic (so-called translational) aspects of venoms from which humans benefit.

Low-dose melittin is safe for intravitreal administration and ameliorates inflammation in an experimental model of uveitis

Uveitis is a group of sight-threatening ocular inflammatory disorders, whose mainstay of therapy is associated with severe adverse events, prompting the investigation of alternative treatments. The peptide melittin (MEL) is the major component of Apis mellifera bee venom and presents anti-inflammatory and antiangiogenic activities, with possible application in ophthalmology. This work aims to investigate the potential of intravitreal MEL in the treatment of ocular diseases involving inflammatory processes, especially uveitis. Safety of MEL was assessed in retinal cells, chick embryo chorioallantoic membranes, and rats. MEL at concentrations safe for intravitreal administration showed an antiangiogenic activity in the chorioallantoic membrane model comparable to bevacizumab, used as positive control. A protective anti-inflammatory effect in retinal cells stimulated with lipopolysaccharide (LPS) was also observed, without toxic effects. Finally, rats with bacille Calmette-Guerin- (BCG) induced uveitis treated with intravitreal MEL showed attenuated disease progression and improvement of clinical, morphological, and functional parameters, in addition to decreased levels of proinflammatory mediators in the posterior segment of the eye. These effects were comparable to the response observed with corticosteroid treatment. Therefore, MEL presents adequate safety profile for intraocular administration and has therapeutic potential as an anti-inflammatory and antiangiogenic agent for ocular diseases.

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Melittin at low concentration is safe for intravitreal administration.

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The antiangiogenic effect of melittin on the chorioallantoic membrane model is comparable to bevacizumab.

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Melittin protects retinal cells from inflammatory response induced by lipopolysaccharide.

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Melittin improves clinical, functional and morphological signs of inflammation in rats with BCG-induced uveitis.

Euphorbia hirta Leaf Ethanol Extract Suppresses TNF-α/IFN-γ-Induced Inflammatory Response via Down-Regulating JNK or STAT1/3 Pathways in Human Keratinocytes

Skin inflammation may cause allergic diseases such as allergic rhinitis, asthma, and atopic dermatitis. Euphorbia hirta (E. hirta) is a member of the Euphorbiaceae family and is well-known for its anti-asthma effects. E. hirta has traditionally been used to treat respiratory ailments, dysentery, jaundice, and digestive problems. However, its effects on skin inflammation remain unclear. Here, we determined the effects of 70% ethanol extract of E. hirta leaves (ELE) in vitro using human keratinocyte HaCaT cells, which constitute most epidermal skin cells. We determined the inhibitory effects of ELE on the inflammation caused by tumor necrosis factor (TNF)-α/interferon (IFN)-γ in keratinocytes using ELISA, immunoblotting, and qRT-PCR assay. ELE was found to reduce the production and mRNA expression of pro-inflammatory cytokines such as TNF-α or interleukin-6 and the expression of various proteins, including signal transducers, activators of transcription 1/3, and mitogen-activated protein kinase. Expression levels of these proteins were found to be upregulated in the TNF-α/IFN-γ-stimulated condition and downregulated by ELE treatment. These results indicate that ELE protects HaCaT cells against TNF-α/IFN-γ-induced skin inflammation.

Bee Venom and Its Major Component Melittin Attenuated Cutibacterium acnes- and IGF-1-Induced Acne Vulgaris via Inactivation of Akt/mTOR/SREBP Signaling Pathway

Acne vulgaris is the most common disease of the pilosebaceous unit. The pathogenesis of this disease is complex, involving increased sebum production and perifollicular inflammation. Understanding the factors that regulate sebum production is important in identifying novel therapeutic targets for the treatment of acne. Bee Venom (BV) and melittin have multiple effects including antibacterial, antiviral, and anti-inflammatory activities in various cell types. However, the anti-lipogenic mechanisms of BV and melittin have not been elucidated. We investigated the effects of BV and melittin in models of Insulin-like growth factor-1 (IGF-1) or Cutibacterium acnes (C. acnes)-induced lipogenic skin disease. C. acnes or IGF-1 increased the expression of sterol regulatory element-binding protein-1 (SREBP-1) and proliferator-activated receptor gamma (PPAR-γ), transcription factors that regulate numerous genes involved in lipid biosynthesis through the protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/SREBP signaling pathway. In this study using a C. acnes or IGF-1 stimulated lipogenic disease model, BV and melittin inhibited the increased expression of lipogenic and pro-inflammatory factor through the blockade of the Akt/mTOR/SREBP signaling pathway. This study suggests for the first time that BV and melittin could be developed as potential natural anti-acne agents with anti-lipogenesis, anti-inflammatory, and anti-C. acnes activity.

The effects of bee venom on liver and skeletal muscle in exhaustive swimming rats

Oxidative damage and proinflammatory cytokines are involved in exhaustive exercise-induced fatigue. This study aimed to investigate the effects of bee venom, a natural toxin, on fatigue and tissue damage in rats that underwent forced swimming exercise. Rats were divided into four groups: control, swimming exercise (SE), bee venom (BV) and swimming exercise + bee venom (SE + BV). SE and SE + BV groups were subjected to forced swimming (load of 7% body weight) for 5 days. BV and SE + BV groups were injected with 1 mg/kg BV subcutaneously. Swimming time, blood lactate and TNF-α levels, MDA and GSH levels in liver and gastrocnemius muscle were evaluated. Swimming time was shorter in SE + BV group than SE group. There was no difference in lactate levels between SE and SE + BV groups. MDA and GSH levels were increased in SE, BV and SE + BV groups. TNF-α levels were increased in BV group compared to control and SE groups. Our study demonstrated that BV administration before exhaustive exercise in rats did not provide anti-fatigue effect. Additionally, BV did not show anti-inflammatory activity and had different effects on antioxidant capacity at tissue level. Further research might explore the effects of different doses and durations of BV on exhaustive exercise.

The bee venom active compound melittin protects against bicuculline-induced seizures and hippocampal astrocyte activation in rats

Epilepsy is a chronic neuropathology characterized by an abnormal hyperactivity of neurons that generate recurrent, spontaneous, paradoxical and synchronized nerve impulses, leading or not to seizures. This neurological disorder affects around 70 million individuals worldwide. Pharmacoresistance is observed in about 30% of the patients and long-term use of antiepileptics may induce serious side effects. Thus, there is an interest in the study of the therapeutic potential of bioactive substances isolated from natural products in the treatment of epilepsy. Arthropod venoms contain neurotoxins that have high affinity for molecular structures in the neural tissue such as receptors, transporters and ion channels both in glial and neuronal membranes. This study evaluated the potential neuroprotective effect of melittin (MEL), an active compound of bee venom, in the bicuculline-induced seizure model (BIC) in rats. Male Wistar rats (3 months, 250-300 g) were submitted to surgery for the implantation of a unilateral cannula in the lateral ventricle. After the recovery period, rats received a microinjection of saline solution or MEL (0.1 mg per animal). Firstly, rats were evaluated in the open field (20 min) and in the elevated plus maze (5 min) tests after received microinjection of saline or MEL. After, 30 min later animals received BIC (100 mg/ml) or saline, and their behaviors were analyzed for 20 min in the open field according to a seizure scale. At the end, rats were euthanized, brains collected and processed to glial fibrillary acidic protein (GFAP) immunohistochemistry evaluation. No changes were observed in MEL-treated rats in the open field and elevated plus maze. However, 90% of MEL-treated animals were protected against seizures induced by BIC. There was an increase in the latency for the onset of seizures, accompanied by a reduction of GFAP-immunoreactivity cells in the dentate gyrus and CA1. Thus, our study suggests that MEL has an anticonvulsant potential, and further studies are needed to elucidate the mechanisms involved in this action.

Future Directions for the Discovery of Natural Product-Derived Immunomodulating Drugs

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology, with contributions from a Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.

The Anti-Inflammatory and Anti-Pruritus Mechanisms of Huanglian Jiedu Decoction in the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic skin disease driven by a T-cell-mediated immune response, with inflammation and pruritus being its main clinical manifestations. Huanglian Jiedu decoction (HLJDT), which is an ancient Chinese medicine herbal formula derived from Wai-Tai-Mi-Yao, is a potentially effective treatment for AD. We aimed to clarify the anti-inflammatory and anti-pruritus mechanisms of HLJDT in AD treatment. We performed immunohistochemistry, Western blotting, reverse transcriptase-polymerase chain reaction, Luminex-based direct multiplex immunoassay, enzyme-linked immunosorbent assays, and flow cytometry to address the abovementioned aims. HLJDT significantly reduced clinical symptoms and ear swelling in AD-like mice by inhibiting the production of cytokines [histamine, interleukin (IL)-3, IL-4, IL-5, IL-13, IL-17A, IL-31, and IL-33], substance P (SP), transient receptor potential cation channel subfamily V member 1 (TRPV-1), and gastrin-releasing peptide (GRP). Additionally, HLJDT significantly suppressed the protein expression levels and positive cell percentage of CD28, CD80, CD86, CD207, CD326, MHCII, and OX40 in the lymphoid nodes. Moreover, HLJDT significantly suppressed mRNA and protein expression of tyrosine–protein kinase (JAK1), histamine H4 receptor, and IL-4Rα, as well as the protein expression of GRP, SP, and TRPV-1 in the root ganglion. Our findings indicate that HLJDT can treat AD by regulating the antigen presentation function of dendritic cells, weakening T-lymphocyte activation, and subsequently exerting anti-inflammatory and anti-pruritus effects.

Gardenia jasminoides extract ameliorates DfE-induced atopic dermatitis in mice through restoration of barrier function and T-helper 2-mediated immune response

Atopic dermatitis (AD) leads to skin barrier abnormalities and immune dysfunction. As the topical steroids commonly used to treat AD have side effects from long-term use, research into safer treatments for AD is greatly needed. The medicinal herb Gardenia jasminoides improves AD symptoms via skin barrier activation and T helper 2-mediated immune response regulation. Crocin, a bioactive component within the extract, is dispensible for its restorative effects. As such, this work explored the effects of Gardenia jasminoides extract without crocin (GjexCr) on AD symptoms in a DfE-induced AD model in 6-week-old male NC/Nga mice (25.0 ± 0.25 g, n = 10 each, 6 groups). Using histological and behavioral assays, the effects of GjexCr on dermatitis scores, scratching behavior, skin barrier activation, and serum levels of IgE, chemokines, and cytokines were analyzed. In addition, the major components from the GjexCr extract were analyzed by high-performance liquid chromatography and validated in the AD model. GjexCr reduced ear thickness due to hyperkeratosis, dermal thickening, and scratching behavior and restored dermatitis scores in AD-induced mice. GjexCr administration also decreased inflammation and mast cell infiltration, as well as modulated skin barrier recovery by upregulating the production of epidermal proteins. Moreover, GjexCr administration attenuated imbalanced immune responses. Furthermore, geniposide, the main component of GjexCr, improved AD symptoms in DfE-treated NC/Nga mice. Thus, GjexCr could be a suitable treatment for protecting the skin barrier in AD-like skin lesions and a potential therapy for AD.

Cosmetic Applications of Bee Venom

Bee venom (BV) is a typical toxin secreted by stingers of honeybee workers. BV and BV therapy have long been attractive to different cultures, with extensive studies during recent decades. Nowadays, BV is applied to combat several skin diseases, such as atopic dermatitis, acne vulgaris, alopecia, vitiligo, and psoriasis. BV is used extensively in topical preparations as cosmetics and used as dressing for wound healing, as well as in facemasks. Nevertheless, the safety of BV as a therapeutic choice has always been a concern due to the immune system reaction in some people due to BV use. The documented unfavorable impact is explained by the fact that the skin reactions to BV might expand to excessive immunological responses, including anaphylaxis, that typically resolve over numerous days. This review aims to address bee venom therapeutic uses in skin cosmetics.

Differential uptake of three clinically relevant allergens by human plasmacytoid dendritic cells

Background

Human plasmacytoid dendritic cells (pDC) have a dual role as interferon-producing and antigen-presenting cells. Their relevance for allergic diseases is controversial. and the impact of pDC on allergic immune responses is poorly understood.

Methods

This in vitro study on human pDC isolated from peripheral blood was designed to compare side by side the uptake of three clinically relevant representative allergens: fluorochrome-labeled house dust mite Der p 1, Bee venom extract from Apis mellifera (Api) and the food allergen OVA analyzed flow cytometry and confocal microscopy.

Results

We found that the internalization and its regulation by TLR9 ligation was significantly different between allergens in terms of time course and strength of uptake. Api and OVA uptake in pDC of healthy subjects was faster and reached higher levels than Der p 1 uptake. CpG ODN 2006 suppressed OVA uptake and to a lesser extent Der p 1, while Api internalization was not affected. All allergens colocalized with LAMP1 and EEA1, with Api being internalized particularly fast and reaching highest intracellular levels in pDC. Of note, we could not determine any specific differences in antigen uptake in allergic compared with healthy subjects.

Conclusions

To our knowledge this is the first study that directly compares uptake regulation of clinically relevant inhalative, injective and food allergens in pDC. Our findings may help to explain differences in the onset and severity of allergic reactions as well as in the efficiency of AIT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12948-021-00163-8.

Applications and evolution of melittin, the quintessential membrane active peptide

Melittin, the main venom component of the European Honeybee, is a cationic linear peptide-amide of 26 amino acid residues with the sequence: GIGAVLKVLTTGLPALISWIKRKRQQ-NH₂. Melittin binds to lipid bilayer membranes, folds into amphipathic α-helical secondary structure and disrupts the permeability barrier. Since melittin was first described, a remarkable array of activities and potential applications in biology and medicine have been described. Melittin is also a favorite model system for biophysicists to study the structure, folding and function of peptides and proteins in membranes. Melittin has also been used as a template for the evolution of new activities in membranes. Here we overview the rich history of scientific research into the many activities of melittin and outline exciting future applications.

Detoxification of Bee Venom Increases Its Anti-inflammatory Activity and Decreases Its Cytotoxicity and Allergenic Activity

Bee venom is a medicinal product that is widely used in traditional therapies owing to its excellent anti-inflammatory activity. However, the use of bee venom has shown adverse effects. Therefore, there is a need for research that can remove the cytotoxicity of bee venom and enhance its efficacy. In this study, we hydrolyzed melittin, the main component of bee venom, and removed the other components to eliminate the toxicity of bee venom. To compare the efficacy of bee venom and detoxified bee venom, we examined their antioxidant effects using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. In addition, cytotoxicity was confirmed in MCF 10A and RAW 264.7 cells, using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. Detoxified bee venom showed a strong antioxidant activity and decreased a cytotoxicity in MCF 10A and RAW 264.7 cells. The anti-inflammatory activity of detoxified bee venom and bee venom were assessed by comparison of the expression of inflammatory cytokine mRNA and phosphorylation of IκBα in RAW 264.7 cells. Degranulation in RBL-2H3 cells was analyzed through β-hexosaminidase release assay to confirm the allergenic activity of bee venom and detoxified bee venom. Treatment of the detoxified bee venom inhibited inflammatory cytokine mRNA expression, IκBα phosphorylation, and β-hexosaminidase release. Taken together, the results indicated that compared to bee venom, detoxified bee venom exhibited decreased cytotoxicity and allergenicity and increased anti-inflammatory activity. In conclusion, detoxification of bee venom efficiently decreases the adverse effects, making it suitable for medicinal applications.

Epigallocatechin gallate/L-ascorbic acid-loaded poly-γ-glutamate microneedles with antioxidant, anti-inflammatory, and immunomodulatory effects for the treatment of atopic dermatitis

Epigallocatechin gallate (EGCG) is a potential therapeutic agent for treatment of atopic dermatitis (AD) due to its antioxidant and anti-inflammatory activities. However, inherent instability of EGCG greatly limits its bioavailability and clinical efficacy. In this study, we developed a poly-γ-glutamate (γ-PGA)-based microneedle (MN) formulation capable of maintaining EGCG's stability and efficiently delivering EGCG into the skin to ameliorate AD symptoms. The γ-PGA MN can not only protect EGCG from oxidation, but also serve as an immunomodulator to downregulate T helper type 2 (Th2)-type immune responses. Encapsulation of EGCG into the γ-PGA MN and utilization of L-ascorbic acid (AA) as a stabilizer preserved 95% of its structural stability and retained 93% of its initial antioxidant activity after 4 weeks of storage. Once-weekly administration of EGCG/AA-loaded MNs to an Nc/Nga mouse model of AD for 4 weeks significantly ameliorated skin lesions and epidermal hyperplasia by reducing serum IgE (from 12156 ± 1344 to 5555 ± 1362  ng/mL) and histamine levels (from 81 ± 18 to 40 ± 5 pg/mL) and inhibiting IFN-γ (from 0.10 ± 0.01 to 0.01 pg/mg total protein) and Th2-type cytokine production, when compared to the AD (no treatment) group (p < 0.05). Notably, once-weekly MN therapy was at least as effective as the daily topical application of an EGCG + AA solution but markedly reduced the administration frequency and required dose. These results show that EGCG/AA-loaded γ-PGA MNs may be a convenient and promising therapeutic option for AD treatment. STATEMENT OF SIGNIFICANCE: This study describes epigallocatechin gallate (EGCG)/L-ascorbic acid (AA)-loaded poly-γ-glutamate (γ-PGA) microneedles (MN) capable of providing antioxidant, anti-inflammatory, and immunomodulatory effects on inflamed skin for ameliorating atopic dermatitis (AD) symptoms in Nc/Nga mice. After skin insertion, the γ-PGA MN can be quickly dissolved in the skin and remain in the dermis for sustained release of encapsulated active ingredients for 6 days. We demonstrated that once-weekly MN therapy effectively alleviated skin lesions and modulated immune response to relieve Th2-polarized allergic response in mice. Once-weekly MN dosing regimen may provide patients with a more convenient, therapeutically equivalent option to daily topical dosing, and may increase compliance and long-term persistence with AD therapy.

Melittin ameliorates inflammation in mouse acute liver failure via inhibition of PKM2-mediated Warburg effect

Acute liver failure (ALF) is a fatal clinical syndrome with no special drug. Recent evidence shows that modulation of macrophage to inhibit inflammation may be a promising strategy for ALF treatment. In this study we investigated the potential therapeutic effects of melittin, a major peptide component of bee venom both in mice model of ALF and in LPS-stimulated macrophages in vitro, and elucidated the underlying mechanisms. ALF was induced in mice by intraperitoneal injection of D-galactosamine/LPS. Then the mice were treated with melittin (2, 4, and 8 mg/kg, ip). We showed that melittin treatment markedly improved mortality, attenuated severe symptoms and signs, and alleviated hepatic inflammation in D-galactosamine/LPS-induced ALF mice with the optimal dose being 4 mg/kg. In addition, melittin within the effective doses did not cause significant in vivo toxicity. In LPS-stimulated RAW264.7 macrophages, melittin (0.7 μM) exerted anti-oxidation and anti-inflammation effects. We showed that LPS stimulation promoted aerobic glycolysis of macrophages through increasing glycolytic rate, upregulated the levels of Warburg effect-related enzymes and metabolites including lactate, LDHA, LDH, and GLUT-1, and activated Akt/mTOR/PKM2/HIF-1α signaling. Melittin treatment suppressed M2 isoform of pyruvate kinase (PKM2), thus disrupted the Warburg effect to alleviate inflammation. Molecular docking analysis confirmed that melittin targeted PKM2. In LPS-stimulated RAW264.7 macrophages, knockdown of PKM2 caused similar anti-inflammation effects as melittin did. In D-galactosamine/LPS-induced ALF mice, melittin treatment markedly decreased the expression levels of PKM2 and HIF-1α in liver. This work demonstrates that melittin inhibits macrophage activation-mediated inflammation via inhibition of aerobic glycolysis by targeting PKM2, which highlights a novel strategy of using melittin for ALF treatment.

Effect of Neferine on DNCB-Induced Atopic Dermatitis in HaCaT Cells and BALB/c Mice

Atopic dermatitis (AD) is a chronic and persistent inflammatory skin disease characterized by eczematous lesions and itching, and it has become a serious health problem. However, the common clinical treatments provide limited relief and are accompanied by adverse effects. Therefore, there is a need to develop novel and effective therapies to treat AD. Neferine is a small molecule compound isolated from the green embryo of the mature seeds of lotus (Nelumbo nucifera). It has a bisbenzylisoquinoline alkaloid structure. Relevant studies have shown that neferine has many pharmacological and biological activities, including anti-inflammatory, anti-thrombotic, and anti-diabetic activities. However, there are very few studies on neferine in the skin, especially the related effects on inflammatory skin diseases. In this study, we proved that it has the potential to be used in the treatment of atopic dermatitis. Through in vitro studies, we found that neferine inhibited the expression of cytokines and chemokines in TNF-α/IFN-γ-stimulated human keratinocyte (HaCaT) cells, and it reduced the phosphorylation of MAPK and the NF-κB signaling pathway. Through in vivo experiments, we used 2,4-dinitrochlorobenzene (DNCB) to induce atopic dermatitis-like skin inflammation in a mouse model. Our results show that neferine significantly decreased the skin barrier damage, scratching responses, and epidermal hyperplasia induced by DNCB. It significantly decreased transepidermal water loss (TEWL), erythema, blood flow, and ear thickness and increased surface skin hydration. Moreover, it also inhibited the expression of cytokines and the activation of signaling pathways. These results indicate that neferine has good potential as an alternative medicine for the treatment of atopic dermatitis or other skin-related inflammatory diseases.

Genistein suppresses allergic contact dermatitis through regulating the MAP2K2/ERK pathway

Genistein is one of the main components of soybeans and has been reported to be a potential candidate for the treatment of obesity, cancer, osteoporosis and cardiovascular diseases. Recently, genistein has been shown to have therapeutic effects on some chronic skin diseases, but its underlying mechanisms remain unclear. In this study, we evaluated the role of genistein in alleviating squaric acid dibutylester (SADBE)-induced allergic contact dermatitis (ACD) in mice, and elucidated the potential molecular mechanisms in human keratinocyte (HaCaT) cell line. The impacts of genistein on the production of pro-inflammatory chemokines and cytokines including CXCL9, TSLP, TNF-α, IL-1β and IL-6 in the skin and serum of ACD mice were assessed, as well as the phosphorylation of components in the MAPK and JAK-STAT3 signaling pathways in the skin and dorsal root ganglions (DRGs). The results showed that genistein exerted protective effects on skin damage and inflammatory cell infiltration. Moreover, genistein significantly inhibited the increased expressions of pro-inflammatory factors in skin and peripheral blood, and down-regulated the levels of p-ERK, p-p38 and p-STAT3 in skin and DRGs. Furthermore, genistein inhibited the phosphorylation of ERK and STAT3 to downregulate the expression of cytokines and chemokines, and feedback downregulate phospho-p38 in TNF-α/IFN-γ-induced HaCaT cells. The genistein-mediated inhibitory effect on the MAPK pathway can be reversed by siMAP2K2 but not by siMAP2K4. Altogether, our findings demonstrated that genistein exhibits strong antipruritic and anti-inflammatory effects in ACD mice by inhibiting the production of pro-inflammatory cytokines and intracellular MAP2K2/ERK cell signaling, which makes genistein a potentially valuable candidate for the treatment of skin conditions and systemic syndromes in the setting of contact dermatitis.

Biotechnologically Produced Lavandula angustifolia Mill. Extract Rich in Rosmarinic Acid Resolves Psoriasis-Related Inflammation Through Janus Kinase/Signal Transducer and Activator of Transcription Signaling

Psoriasis is a common skin pathology, characterized by dysregulation of epidermal keratinocyte function attended by persistent inflammation, suggesting that molecules with anti-inflammatory potential may be effective for its management. Rosmarinic acid (RA) is a natural bioactive molecule known to have an anti-inflammatory potential. Here we examined the effect of biotechnologically produced cell suspension extract of Lavandula angustifolia Mill (LV) high in RA content as treatment for psoriasis-associated inflammation in human keratinocytes. Regulatory genes from the nuclear factor kappa B (NF-κB) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathways were upregulated upon stimulation with a combination of interferon gamma (IFN-γ), interleukin (IL)-17A and IL-22. We also observed that both LV extract and RA could inhibit JAK2, leading to reduced STAT1 phosphorylation. Further, we demonstrated that LV extract inhibited phosphoinositide 3-kinases (PI3K) and protein kinase B (AKT), which could be implicated in reduced hyperproliferation in keratinocytes. Collectively, these findings indicate that the biotechnologically produced LV extract resolved psoriasis-like inflammation in human keratinocytes by interfering the JAK2/STAT1 signaling pathway and its effectiveness is due to its high content of RA (10%). Hence, both LV extract and pure RA possess the potential to be incorporated in formulations for topical application as therapeutic approach against psoriasis.

RNA-Seq Identifies Marked Th17 Cell Activation and Altered CFTR Expression in Different Atopic Dermatitis Subtypes in Chinese Han Populations

Background

Patients with atopic dermatitis (AD) exhibit phenotypic variability in ethnicity and IgE status. In addition, some patients develop other allergic conditions, such as allergic rhinitis (AR), in subsequent life. Understanding the heterogeneity of AD would be beneficial to phenotype-specific therapies.

Methods

Twenty-eight Chinese AD patients and 8 healthy volunteers were enrolled in the study. High-throughput transcriptome sequencing was conducted on lesional and nonlesional skin samples from 10 AD patients and matched normal skin samples from 5 healthy volunteers. Identification of differentially expressed genes (DEGs), KEGG pathway analyses, and sample cluster analyses were conducted in the R software environment using the DEseq2, ClusterProfiler, and pheatmap R packages, respectively. qRT-PCR, Western blotting, and ELISA were used to detect gene expression levels among subtypes. Correlation analysis was performed to further investigate their correlation with disease severity.

Results

A total of 25,798 genes were detected per sample. Subgroup differential expression analysis and functional enrichment analysis revealed significant changes in the IL17 signaling pathway in Chinese EAD patients but not in IAD patients. DEGs enriched in cytokine-cytokine receptor interactions and gland secretion were considered to be associated with atopic march. Further investigations confirmed a marked IL17A upregulation in Chinese EAD with a positive relationship with total IgE level and AD severity. In addition, increased IL17A in AD patients with AR demonstrated a closer association with AR severity than IL4R. Moreover, AQP5 and CFTR were decreased in the lesions of AD patients with AR. The CFTR mRNA expression level was negatively associated with the skin IL17A level and AR severity.

Conclusion

Our research characterized marked Th17 activation in Chinese EAD patients, and altered expression of IL17A, IL4R, AQP5, and CFTR in AD patients with AR was associated with AR severity. It partially explained the phenotypic differences of AD subtypes and provided potential references for endotype-targeted therapy.