Neuroprotective effects of bee venom phospholipase A2 in the 3xTg AD mouse model of Alzheimer's disease

Bee venom as a promising therapeutic strategy in central nervous system diseases

Central nervous system (CNS) disorders are one of the leading health problems today, accounting for a large proportion of global morbidity and mortality. Most these disorders are characterized by high levels of oxidative stress and intense inflammatory responses in degenerated neuronal tissues. While extensive research has been conducted on CNS diseases, but few breakthroughs have been made in treatment methods. To date, there are no disease-modifying drugs available for CNS treatment, underscoring the urgent need for finding effective medications. Bee venom (BV), which is produced by honeybee workers' stingers, has been a subject of interest and study across various cultures. Over the past few decades, extensive research has focused on BV and its therapeutic potentials. BV consists a variety of substances, mainly proteins and peptides like melittin and phospholipase A2 (PLA2). Research has proven that BV is effective in various medical conditions, including pain, arthritis and inflammation and CNS disorders such as Multiple sclerosis, Alzheimer's disease and Parkinson's disease. This review provides a comprehensive overview of the existing knowledge concerning the therapeutic effects of BV and its primary compounds on various CNS diseases. Additionally, we aim to shed light on the potential cellular and molecular mechanisms underlying these effects.

Microneedle-mediated drug delivery for neurological diseases

Neurological disorders, including brain injury, brain tumors, and neurodegenerative diseases, rank as the second leading cause of death worldwide. Exploring effective new treatments for neurological disorders has long been a hot research issue in clinical practice. Recently, microneedles (MNs) have attracted much attention due to their designation as a "painless and non-invasive" novel transdermal delivery method, characterized by their biocompatibility and sustainability. The advantages of MNs open an avenue for potential therapeutic interventions targeting neurological disorders. This review presents a concise overview of progress in the field of MNs, with highlights on the application in the treatment of neurological disorders. Notably, trends in the development of MNs and future challenges are also discussed.

An insight into structure-activity relationship of naturally derived biological macromolecules for the treatment of Alzheimer's disease: a review

Alzheimer's disease (AD) is a neurological disorder that affects millions of people worldwide. There are currently no cures for AD, although various drugs are used to manage the symptoms and reduce the disease's progression. AChE inhibitors such as rivastigmine, donepezil, galantamine, and the NMDA glutamate receptor antagonist memantine are currently FDA-approved drugs used in the treatment of AD. Recently, naturally derived biological macromolecules have shown promising results in the treatment of AD. Several biological macromolecules derived from natural sources are in various stages of preclinical and clinical trials. During the literature search, it was observed that there is a lack of a comprehensive review that particularly focuses on the role of naturally derived biological macromolecules (protein, carbohydrates, lipids, and nucleic acids) in the treatment of AD and the structure-activity relationship (SAR) approach for understanding the medicinal chemistry perspective. This review focuses on the SAR and probable mechanisms of action of biological macromolecules derived from natural sources for the treatment of AD, including peptides, proteins, enzymes, and polysaccharides. The paper further addresses the therapeutic possibilities of monoclonal antibodies, enzymes, and vaccines for the treatment of AD. Overall, the review provides insight into the SAR of naturally derived biological macromolecules in the treatment of AD. The ongoing research in this field holds great promise for the future development of AD treatment and provides hope for individuals affected by this devastating disease.Communicated by Ramaswamy H. Sarma.

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.

Animal Venoms as Potential Source of Anticonvulsants

Epilepsy affects millions of people worldwide, and there is an urgent need to develop safe and effective therapeutic agents. Animal venoms contain diverse bioactive compounds like proteins, peptides, and small molecules, which may possess medicinal properties against epilepsy. In recent years, research has shown that venoms from various organisms such as spiders, ants, bees, wasps, and conus snails have anticonvulsant and antiepileptic effects by targeting specific receptors and ion channels. This review underscores the significance of purified proteins and toxins from these sources as potential therapeutic agents for epilepsy. In conclusion, this review emphasizes the valuable role of animal venoms as a natural resource for further exploration in epilepsy treatment research.

Differential roles of regulatory T cells in Alzheimer's disease

Regulatory T (Treg) cells interact with a variety of resident cells and infiltrated immune cells in the central nervous system (CNS) to modulate neuroinflammation and neurodegeneration. Extracellular amyloid-β (Aβ) peptide deposition and secondary persistent inflammation due to activation of microglia, astrocytes, and infiltrated immune cells contribute to Alzheimer's disease (AD)-related neurodegeneration. The majority of evidence supports the neuroprotective effects of Treg cells in AD. In the early stages of AD, appropriate Treg cell activity is required for the induction of microglia and astrocyte phagocytic activity in order to clear A deposits and prevent neuroinflammation. Such neuroprotective impacts were in part attributed to the ability of Treg cells to suppress deleterious and/or boost beneficial functions of microglia/astrocytes. In the later stages of AD, an effective Treg cell activity needs to prevent neurotoxicity and neurodegeneration. Treg cells can exert preventive effects on Th1-, and Th17 cell-related pathologic responses, whilst potentiating Th2-mediated protective activity. The impaired Treg cell-related immunomodulatory mechanisms have been described in AD patients and in related animal models which can contribute to the onset and progression of AD. This review aimed to provide a comprehensive figure regarding the role of Treg cells in AD while highlighting potential therapeutic approaches.

Improving productive performance, immunity, and health status of growing rabbits by using honey bee venom (Apis mellifera)

To investigate the effect of bee venom (BV) as a natural growth promotor on growing rabbits as an alternative to antibiotics, sixty 35-day-old Californian male rabbits with an average body weight of 584 ± 9 gm were randomly divided into five equal groups as follows: The 2nd group received drinking water supplied with 10 mg Oxytetracycline (OXT), while the 3rd, 4th, and 5th groups received 2, 4 and 8 mg bee venom (BV)/kg body weight/day in drinking water, and the first group was served as a control group. The growth performance features were positively impacted by adding BV (p ≤ 0.01) compared to the control, whereas LBW and BWG increased and FI reduced. Significantly improved carcass characteristics (p ≤ 0.01) as a result of the BV supplementation. Blood characteristics showed a significant reduction (p ≤ 0.01) in liver enzyme activities and Cholesterol, Triglycerides, and Low-density lipoproteins Cholesterol (LDL) as affected by BV treatment; inversely, total protein and globulin were significantly increased (p ≤ 0.01). Similarly, BV had a positive effect (p ≤ 0.01) on anti-oxidant status (Total anti-oxidant capacity (TAC), Glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase (CAT)). In contrast, the lipid peroxidation biomarker (Malondialdehyde (MDA)) was significantly decreased. The immunoglobulin (IgG and IgM) was significantly increased (p ≤ 0.01) by BV treatment. There was a positive effect of low BV levels on decreasing both cecum TBC and pathogenic bacterial count (Salmonella spp., E.coli spp., Proteus spp., and Clostridia spp.) that was significant (p ≤ 0.01). In conclusion, BV can be a natural growth promoter to enhance growth performance traits, immunological and anti-oxidative responses, and reduce pathogenic bacteria in the hindgut of growing rabbits.

Bee venom (Apis mellifera L.) rescues zinc oxide nanoparticles induced neurobehavioral and neurotoxic impact via controlling neurofilament and GAP-43 in rat brain

This study investigated the possible beneficial role of the bee venom (BV, Apis mellifera L.) against zinc oxide nanoparticles (ZNPs)-induced neurobehavioral and neurotoxic impacts in rats. Fifty male Sprague Dawley rats were alienated into five groups. Three groups were intraperitoneally injected distilled water (C 28D group), ZNPs (100 mg/kg b.wt) (ZNPs group), or ZNPs (100 mg/kg.wt) and BV (1 mg/ kg.bwt) (ZNPs + BV group) for 28 days. One group was intraperitoneally injected with 1 mL of distilled water for 56 days (C 56D group). The last group was intraperitoneally injected with ZNPs for 28 days, then BV for another 28 days at the same earlier doses and duration (ZNPs/BV group). Depression, anxiety, locomotor activity, spatial learning, and memory were evaluated using the forced swimming test, elevated plus maze, open field test, and Morris water maze test, respectively. The brain contents of dopamine, serotonin, total antioxidant capacity (TAC), malondialdehyde (MDA), and Zn were estimated. The histopathological changes and immunoexpressions of neurofilament and GAP-43 protein in the brain tissues were followed. The results displayed that BV significantly decreased the ZNPs-induced depression, anxiety, memory impairment, and spatial learning disorders. Moreover, the ZNPs-induced increment in serotonin and dopamine levels and Zn content was significantly suppressed by BV. Besides, BV significantly restored the depleted TAC but minimized the augmented MDA brain content associated with ZNPs exposure. Likewise, the neurodegenerative changes induced by ZNPs were significantly abolished by BV. Also, the increased neurofilament and GAP-43 immunoexpression due to ZNPs exposure were alleviated with BV. Of note, BV achieved better results in the ZNPs + BV group than in the ZNPs/BV group. Conclusively, these results demonstrated that BV could be employed as a biologically effective therapy to mitigate the neurotoxic and neurobehavioral effects of ZNPs, particularly when used during ZNPs exposure.

Pharmacokinetics and Tissue Distribution of Bee Venom-Derived Phospholipase A2 Using a Sandwich ELISA after Subcutaneous Injection of New Composition Bee Venom in Rats

Bee venom is a traditional drug used to treat the nervous system, musculoskeletal system, and autoimmune diseases. A previous study found that bee venom and one of its components, phospholipase A2, can protect the brain by suppressing neuroinflammation and can also be used to treat Alzheimer's disease. Thus, new composition bee venom (NCBV), which has an increased phospholipase A2 content of up to 76.2%, was developed as a treatment agent for Alzheimer's disease by INISTst (Republic of Korea). The aim of this study was to characterize the pharmacokinetic profiles of phospholipase A2 contained in NCBV in rats. Single subcutaneous administration of NCBV at doses ranging from 0.2 mg/kg to 5 mg/kg was conducted, and pharmacokinetic parameters of bee venom-derived phospholipase A2 (bvPLA2) increased in a dose-dependent manner. Additionally, no accumulation was observed following multiple dosings (0.5 mg/kg/week), and other constituents of NCBV did not affect the pharmacokinetic profile of bvPLA2. After subcutaneous injection of NCBV, the tissue-to-plasma ratios of bvPLA2 for the tested nine tissues were all <1.0, indicating a limited distribution of the bvPLA2 within the tissues. The findings of this study may help understand the pharmacokinetic characteristics of bvPLA2 and provide useful information for the clinical application of NCBV.

Beneficial Effect of Bee Venom and Its Major Components on Facial Nerve Injury Induced in Mice

Peripheral nerve injury (PNI) is a health problem that affects many people worldwide. This study is the first to evaluate the potential effect of bee venom (BV) and its major components in a model of PNI in the mouse. For that, the BV used in this study was analyzed using UHPLC. All animals underwent a distal section-suture of facial nerve branches, and they were randomly divided into five groups. Group 1: injured facial nerve branches without any treatment. Group 2: the facial nerve branches were injured, and the normal saline was injected similarly as in the BV-treated group. Group 3: injured facial nerve branches with local injections of BV solution. Group 4: injured facial nerve branches with local injections of a mixture of PLA2 and melittin. Group 5: injured facial nerve branches with local injection of betamethasone. The treatment was performed three times a week for 4 weeks. The animals were submitted to functional analysis (observation of whisker movement and quantification of nasal deviation). The vibrissae muscle re-innervation was evaluated by retrograde labeling of facial motoneurons in all experimental groups. UHPLC data showed 76.90 ± 0.13%, 11.73 ± 0.13%, and 2.01 ± 0.01%, respectively, for melittin, phospholipase A2, and apamin in the studied BV sample. The obtained results showed that BV treatment was more potent than the mixture of PLA2 and melittin or betamethasone in behavioral recovery. The whisker movement occurred faster in BV-treated mice than in the other groups, with a complete disappearance of nasal deviation two weeks after surgery. Morphologically, a normal fluorogold labeling of the facial motoneurons was restored 4 weeks after surgery in the BV-treated group, but no such restoration was ever observed in other groups. Our findings indicate the potential of the use of BV injections to enhance appropriate functional and neuronal outcomes after PNI.

The potential for treg-enhancing therapies in nervous system pathologies

While inflammation may not be the cause of disease, it is well known that it contributes to disease pathogenesis across a multitude of peripheral and central nervous system disorders. Chronic and overactive inflammation due to an effector T-cell-mediated aberrant immune response ultimately leads to tissue damage and neuronal cell death. To counteract peripheral and neuroinflammatory responses, research is being focused on regulatory T cell enhancement as a therapeutic target. Regulatory T cells are an immunosuppressive subpopulation of CD4+ T helper cells essential for maintaining immune homeostasis. The cells play pivotal roles in suppressing immune responses to maintain immune tolerance. In so doing, they control T cell proliferation and pro-inflammatory cytokine production curtailing autoimmunity and inflammation. For nervous system pathologies, Treg are known to affect the onset and tempo of neural injuries. To this end, we review recent findings supporting Treg's role in disease, as well as serving as a therapeutic agent in multiple sclerosis, myasthenia gravis, Guillain-Barre syndrome, Parkinson's and Alzheimer's diseases, and amyotrophic lateral sclerosis. An ever-broader role for Treg in the control of neurologic disease has been shown for traumatic brain injury, stroke, neurotrophic pain, epilepsy, and psychiatric disorders. To such ends, this review serves to examine the role played by Tregs in nervous system diseases with a focus on harnessing their functional therapeutic role(s).

Animal toxins: As an alternative therapeutic target following ischemic stroke condition

Globally, Ischemic stroke (IS) has become the second leading cause of mortality and chronic disability. The process of IS has triggered by the blockages of blood vessels to form clots in the brain which initiates multiple interactions with the key signaling pathways, counting excitotoxicity, acidosis, ionic imbalance, inflammation, oxidative stress, and neuronal dysfunction of cells, and ultimately cells going under apoptosis. Currently, FDA has approved only tissue plasminogen activator therapy, which is effective against IS with few limitations. However, the mechanism of excitotoxicity and acidosis has spurred the investigation of a potential candidate for IS therapy. Acid-sensing ion channels (ASICs) and Voltage-gated Ca²⁺ channels (VDCCs) get activated and disturb the brain's normal physiology. Animal toxins are novel inhibitors of ASICs and VDCCs channels and have provided neuroprotective insights into the pathophysiology of IS. This review will discuss the potential directions of translational ASICs and VDCCs inhibitors research for clinical therapies.

Long-Term Administration of Vespa velutina nigrithorax Venom Ameliorates Alzheimer’s Phenotypes in 5xFAD Transgenic Mice

Alzheimer’s disease (AD), the most prevalent neurodegenerative disease, is characterized by progressive and irreversible impairment of cognitive functions. However, its etiology is poorly understood, and therapeutic interventions are limited. Our preliminary study revealed that wasp venom (WV) from Vespa velutina nigrithorax can prevent lipopolysaccharide-induced inflammatory signaling, which is strongly implicated in AD pathogenesis. Therefore, we examined whether WV administration can ameliorate major AD phenotypes in the 5xFAD transgenic mouse model. Adult 5xFAD transgenic mice (6.5 months of age) were treated with WV by intraperitoneal injection at 250 or 400 μg/kg body weight once weekly for 14 consecutive weeks. This administration regimen improved procedural, spatial, and working memory deficits as assessed by the passive avoidance, Morris water maze, and Y-maze tasks, respectively. It also attenuated histological damage and amyloid-beta plaque formation in the hippocampal region and decreased expression levels of pro-inflammatory factors in the hippocampus and cerebrum, while it reduced oxidative stress markers (malondialdehyde in the brain and liver and 8-hydroxy-2′-deoxyguanosine in the plasma). Overall, these findings suggest that long-term administration of WV may alleviate AD-related symptoms and pathological phenotypes.

Alzheimer's Disease: Innovative Therapeutic Approaches Based on Peptides and Nanoparticles

Alzheimer's disease (AD) is the main cause of dementia in the world and its etiology is not yet fully understood. The pathology of AD is primarily characterized by intracellular neurofibrillary tangles and extracellular amyloid-β plaques. Unfortunately, few treatment options are available, and most treat symptoms, as is the case of acetylcholinesterase inhibitors (IAChE) and N-methyl-d-aspartate receptor antagonists. For more than 20 years pharmaceutical research has targeted the "amyloid cascade hypothesis," but this has not produced meaningful results, leading researchers to focus now on other characteristics of the disease and on multitarget approaches. This review aims to evaluate some new treatments that are being developed and studied. Among these are new treatments based on peptides, which have high selectivity and low toxicity; however, these compounds have a short half-life and encounter challenges when crossing the blood-brain barrier. The present review discusses up-and-coming peptides tested as treatments and explores some nanotechnological strategies to overcome the downsides. These compounds are promising, as they not only act on the symptoms but also aim to prevent progressive neuronal loss.

Pharmacokinetic improvement provided by microneedle patch in delivering bee venom, a case study in combating scopolamine-induced neurodegeneration in mouse model

Much research has shown Bee venom to be an effective neuroprotective agent. However, the usual transdermal injection of bee venom poses many pharmacokinetic disadvantages. Here, we compared the administration of bee venom via subcutaneous injection (SC) and via Microneedle patch (MN). Both administrated routes produce significant recovery effects, however: the MN significantly prolongs the bio-significant-and-yet-lower concentration of bee venom in mice bodies. In contrast, SC could produce only a short period of much higher bee venom levels in the blood and brain. We also see that due to the concentration-response-curve of bee venom (represented by melittin): mice bodies do not require much higher bee venom concentration (seen in the SC group) to produce a much more significant neuroprotective effect (than seen in those treated with the MN method). Therefore, a MN could maintain bee venom levels in mice bodies at lower-yet-more-efficient concentrations. This is important, as bee venom can cause more adverse effects and pain sensations, at higher concentrations. For the first time, we confirmed that the pharmacokinetic advantages of MN delivered bee venom also guarantee a holistic neuroprotection effect (which was shown by SC delivered bee venom in previous research). This was proven via the results of the water maze experiments for long-term learning memory assessment and protein analysis of key neuronal regulatory proteins: BDNF, p-CREB, iNOS, and mArhR 1. In conclusion, for situations where we ought to administrate drugs at a more downward amount, such as bee venom, MN can keep the therapeutic concentrations at a lower, yet interestingly, more-efficient level.

Therapeutic Potential of Bee and Scorpion Venom Phospholipase A2 (PLA2): A Narrative Review

Venomous arthropods such as scorpions and bees form one of the important groups with an essential role in medical entomology. Their venom possesses a mixture of diverse compounds, such as peptides, some of which have toxic effects, and enzymatic peptide Phospholipase A2 (PLA2) with a pharmacological potential in the treatment of a wide range of diseases. Bee and scorpion venom PLA2 group III has been used in immunotherapy, the treatment of neurodegenerative and inflammatory diseases. They were assessed for antinociceptive, wound healing, anti-cancer, anti-viral, anti-bacterial, anti-parasitic, and anti-angiogenesis effects. PLA2 has been identified in different species of scorpions and bees. The anti-leishmania, anti-bacterial, anti-viral, and anti-malarial activities of scorpion PLA2 still need further investigation. Many pieces of research have been stopped in the laboratory stage, and several studies need vast investigation in the clinical phase to show the pharmacological potential of PLA2. In this review, the medical significance of PLA2 from the venom of two arthropods, namely bees and scorpions, is discussed.

Crossing borders in Alzheimer's disease: A T cell's perspective

Alzheimer's disease (AD) is the most common form of dementia affecting millions of people worldwide. While different immunotherapies are imminent, currently only disease-modifying medications are available and a cure is lacking. Over the past decade, immunological interfaces of the central nervous system (CNS) and their role in neurodegenerative diseases received increasing attention. Specifically, emerging evidence shows that subsets of circulating CD8⁺ T cells cross the brain barriers and associate with AD pathology. To gain more insight into how the adaptive immune system is involved in disease pathogenesis, we here provide a comprehensive overview of the contribution of T cells to AD pathology, incorporating changes at the brain barriers. In addition, we review studies that provide translation of these findings by targeting T cells to combat AD pathology and cognitive decline. Importantly, these data show that immunological changes in AD are not confined to the CNS and that AD-associated systemic immune changes appear to affect brain homeostasis.

Neuroprotective effects of ex vivo-expanded regulatory T cells on trimethyltin-induced neurodegeneration in mice

Background

Trimethyltin (TMT) is a potent neurotoxicant that leads to hippocampal neurodegeneration. Regulatory T cells (Tregs) play an important role in maintaining the immune balance in the central nervous system (CNS), but their activities are impaired in neurodegenerative diseases. In this study, we aimed to determine whether adoptive transfer of Tregs, as a living drug, ameliorates hippocampal neurodegeneration in TMT-intoxicated mice.

Methods

CD4⁺CD25⁺ Tregs were expanded in vitro and adoptively transferred to TMT-treated mice. First, we explored the effects of Tregs on behavioral deficits using the Morris water maze and elevated plus maze tests. Biomarkers related to memory formation, such as cAMP response element-binding protein (CREB), protein kinase C (PKC), neuronal nuclear protein (NeuN), nerve growth factor (NGF), and ionized calcium binding adaptor molecule 1 (Iba1) in the hippocampus were examined by immunohistochemistry after killing the mouse. To investigate the neuroinflammatory responses, the polarization status of microglia was examined in vivo and in vitro using real-time reverse transcription polymerase chain reaction (rtPCR) and Enzyme-linked immunosorbent assay (ELISA). Additionally, the inhibitory effects of Tregs on TMT-induced microglial activation were examined using time-lapse live imaging in vitro with an activation-specific fluorescence probe, CDr20.

Results

Adoptive transfer of Tregs improved spatial learning and memory functions and reduced anxiety in TMT-intoxicated mice. Additionally, adoptive transfer of Tregs reduced neuronal loss and recovered the expression of neurogenesis enhancing molecules in the hippocampi of TMT-intoxicated mice. In particular, Tregs inhibited microglial activation and pro-inflammatory cytokine release in the hippocampi of TMT-intoxicated mice. The inhibitory effects of TMT were also confirmed via in vitro live time-lapse imaging in a Treg/microglia co-culture system.

Conclusions

These data suggest that adoptive transfer of Tregs ameliorates disease progression in TMT-induced neurodegeneration by promoting neurogenesis and modulating microglial activation and polarization.

Wasp Venom Ameliorates Scopolamine-Induced Learning and Memory Impairment in Mice

This study investigated the effects of wasp venom (WV) from the yellow-legged hornet, Vespa velutina, on scopolamine (SCO)-induced memory deficits in mice, as well as the antioxidant activity in HT22 murine hippocampal neuronal cells in parallel comparison with bee venom (BV). The WV was collected from the venom sac, freeze-dried. Both venoms exhibited free radical scavenging capabilities in a concentration-dependent manner. In addition, the venom treatment enhanced cell viability at the concentrations of ≤40 µg/mL of WV and ≤4 µg/mL of BV in glutamate-treated HT22 cells, and increased the transcriptional activity of the antioxidant response element (ARE), a cis-acting enhancer which regulates the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-downstream antioxidant enzymes. Concurrently, WV at 20 µg/mL significantly increased the expression of a key antioxidant enzyme heme oxygenase 1 (HO-1) in HT22 cells despite no significant changes observed in the nuclear level of Nrf2. Furthermore, the intraperitoneal administration of WV to SCO-treated mice at doses ranged from 250 to 500 µg/kg body weight ameliorated memory impairment behavior, reduced histological injury in the hippocampal region, and reduced oxidative stress biomarkers in the brain and blood of SCO-treated mice. Our findings demonstrate that WV possess the potential to improve learning and memory deficit in vivo while further study is needed for the proper dose and safety measures and clinical effectiveness.

Neuroimaging of Mouse Models of Alzheimer’s Disease

Magnetic resonance imaging (MRI) and positron emission tomography (PET) have made great strides in the diagnosis and our understanding of Alzheimer’s Disease (AD). Despite the knowledge gained from human studies, mouse models have and continue to play an important role in deciphering the cellular and molecular evolution of AD. MRI and PET are now being increasingly used to investigate neuroimaging features in mouse models and provide the basis for rapid translation to the clinical setting. Here, we provide an overview of the human MRI and PET imaging landscape as a prelude to an in-depth review of preclinical imaging in mice. A broad range of mouse models recapitulate certain aspects of the human AD, but no single model simulates the human disease spectrum. We focused on the two of the most popular mouse models, the 3xTg-AD and the 5xFAD models, and we summarized all known published MRI and PET imaging data, including contrasting findings. The goal of this review is to provide the reader with broad framework to guide future studies in existing and future mouse models of AD. We also highlight aspects of MRI and PET imaging that could be improved to increase rigor and reproducibility in future imaging studies.

The Responsiveness of Bee Venom Phospholipase A2 on Regulatory T Cells Correlates with the CD11c+CD206+Population in Human Peripheral Blood Mononuclear Cells

Bee venom phospholipase A2 (bvPLA2) has been reported to have therapeutic effects such as neuroprotection, anti-inflammation, anti-nociception, anti-cancer properties, caused by increasing regulatory T cells (Tregs). The mechanism of Tregs modulation by bvPLA2 has been demonstrated by binding with the mannose receptor, CD206 in experimental models of several diseases. However, it remains unknown whether this mechanism can also be applied in human blood. In this study, we collected peripheral blood samples from healthy donors and analyzed the percentages of monocyte-derived dendritic cells with CD206 (CD206+ DCs) before expansion, the proportion of Tregs, and the subpopulations after expansion treated with bvPLA2 or PBS using flow cytometry and the correlations among them. The percentage of Tregs tended to be higher in the bvPLA2 group than in the control group. There were significant positive correlations between the CD206 population in hPBMC and the proportions of Tregs treated with bvPLA2, especially in the Treg fold change comparing the increase ratio of Tregs in bvPLA2 and in PBS. These findings indicate that bvPLA2 increased the proportion of Tregs in healthy human peripheral blood and the number of CD206+ DCs could be a predictor of the bvPLA2 response of different individuals.

Bee venom Apis mellifera lamarckii rescues blood brain barrier damage and neurobehavioral changes induced by methyl mercury via regulating tight junction proteins expression in rat cerebellum

The objective of the current study is to investigate the protective effect of Egyptian bee venom (BV) against methyl mercury chloride (MMC) induced blood-brain barrier (BBB) damage and neurobehavioral changes. Eighty male Sprague-Dawley rats were randomly grouped into 1st control (C), 2nd BV (0.5 mg/kg S/C for14 days), 3rd MMC (6.7 mg/kg orally/14 days), and 4th MMC + BV group. MMC exposure significantly altered rat cognitive behavior, auditory startle habituation, and swimming performance, increased the exploratory, grooming, and stereotypic behavior. MMC significantly impaired BBB integrity via induction of inflammation, oxidative stress, and down-regulation of tight junction proteins genes (TJPs) mRNA expression levels: Occludin (OCC), Claudins-5 (CLDN5), Zonula occludens-1 (ZO-1), while up-regulated the transforming growth factor-beta (TGF-β) mRNA expression levels. MMC revealed a significantly higher percentage of IgG positive area ratio, a higher index ratio of Iba1, Sox10, and ss-DNA, while index ratio of CD31, neurofilament, and pan neuron showed a significant reduction. Administration of BV significantly regulates the MMC altered behavioral responses, TJPs relative mRNA expression, and the immune-expression markers for specific neural cell types. It could be concluded for the first time that BV retains a promising in vivo protection against MMC-induced BBB dysfunction and neurobehavioral toxicity.

Targeting of adipose tissue macrophages by bee venom phospholipase A2 attenuates high-fat diet-induced obesity

Background/objectives

Adipose tissue macrophages (ATMs) exist in either the M1 or M2 form. The anti-inflammatory M2 ATMs accumulate in lean individuals, whereas the pro-inflammatory M1 ATMs accumulate in obese individuals. Bee venom phospholipase A2 (bvPLA2), a major component in honeybee (Apis mellifera) venom, exerts potent anti-inflammatory effects via interactions with regulatory T cells (Treg) and macrophages. This study investigated the effects of bvPLA2 on a high-fat diet (HFD)-induced obesity in mice.

Subjects/methods

For in vivo experiments, male C57BL/6, CD206-deficient, and Treg-depleted mice models were fed either a normal diet 41.86 kJ (ND, 10 kcal% fat) or high-fat diet 251.16 kJ (HFD, 60 kcal% fat). Each group was i.p. injected with PBS or bvPLA2 (0.5 mg/kg) every 3 days for 11 weeks. Body weight and food intake were measured weekly. Histological changes in the white adipose tissue (WAT), liver, and kidney as well as the immune phenotypes of the WAT were examined. Immune cells, cytokines, and lipid profiles were also evaluated. The direct effects of bvPLA2 on 3T3-L1 pre-adipocytes and bone marrow-derived macrophages were measured in vitro.

Results

bvPLA2 markedly decreased bodyweight in HFD-fed mice. bvPLA2 treatment also decreased lipid accumulation in the liver and reduced kidney inflammation in the mice. It was confirmed that bvPLA2 exerted immunomodulatory effects through the CD206 receptor. In addition, bvPLA2 decreased M1 ATM and alleviated the M1/M2 imbalance in vivo. However, bvPLA2 did not directly inhibit adipogenesis in the 3T3-L1 adipose cells in vitro.

Conclusions

bvPLA2 is a potential therapeutic strategy for the management of obesity by regulating adipose tissue macrophage homeostasis.

Low semen quality and adverse histological changes in testes of adult male mice treated with bee venom (Apis mellifera)

Background

Male infertility has been on the rise since the past seven decades. Recently, in Libya, bee venom therapy (BVT) has become a popular method among alternative healthcare practitioners for treating male infertility. However, a literature search did not find any published studies that investigated the use of BVT for infertility treatment.

Aim

To investigate the effect of bee venom on the male reproductive status through measurements of semen quality parameters and testicular histological changes in adult male mice.

Methods

A total of 48 male mice were randomly divided into three experimental groups (which were subdivided into two subgroups with eight mice each) as follows: control, bee venom sting (BVS), and bee venom injection (BVI). The normal control subgroup mice were not subjected to any treatment, while the vehicle control subgroup mice were injected (i.p.) with 200 μl of 0.9% saline solution. In the BVS-treated subgroups, each mouse was stung by one live bee for five times (BVS-5) or seven times (BVS-7) every third day for 2 or 3 weeks. While each mouse in the BVI-treated subgroups received 23 μg/kg in a dose volume of 200 μl BVIs (i.p.) for five times (BVI-5) or seven times (BVI-7) every third day for 15 or 21 days.

Results

The findings of this study showed that repeated bee venom treatment by sting or injection to adult male mice resulted in a significant decline in testosterone levels, sperm count, sperm motility, and a very significant increase in the percentage of abnormal sperm morphology; also, there were harmful testicular histological changes in the structural organization of seminiferous tubules and degenerative changes in the germinal epithelium compared to control group.

Conclusion

The results of this study provide evidence for the low semen quality and adverse testicular histological changes in male mice treated with bee venom. Hence, there is a desperate need for educating alternative healthcare practitioners and infertile couples about the harmful effects of BVT on reproductive status.

Bee Venom: An Updating Review of Its Bioactive Molecules and Its Health Applications

Bee venom (BV) is usually associated with pain since, when humans are stung by bees, local inflammation and even an allergic reaction can be produced. BV has been traditionally used in ancient medicine and in acupuncture. It consists of a mixture of substances, principally of proteins and peptides, including enzymes as well as other types of molecules in a very low concentration. Melittin and phospholipase A2 (PLA2) are the most abundant and studied compounds of BV. Literature of the main biological activities exerted by BV shows that most studies focuses on the comprehension and test of anti-inflammatory effects and its mechanisms of action. Other properties such as antioxidant, antimicrobial, neuroprotective or antitumor effects have also been assessed, both in vitro and in vivo. Moreover, human trials are necessary to confirm those clinical applications. However, notwithstanding the therapeutic potential of BV, there are certain problems regarding its safety and the possible appearance of adverse effects. On this perspective, new approaches have been developed to avoid these complications. This manuscript is aimed at reviewing the actual knowledge on BV components and its associated biological activities as well as the latest advances on this subject.

Clinical Applications of Bee Venom Acupoint Injection

Bee venom is a complex natural mixture with various pharmaceutical properties. Among these properties, its peptides and enzymes have potential medical therapy for pain relief and inflammation. In clinical settings, this therapy has been used widely to treat diseases by injecting into acupoints. In this article, we have conducted various research from PubMed, Cochrane Library, and Clinical Key from inception of July 2020. The results revealed that bee venom therapy has been reported effective in anti-inflammatory, antiapoptosis, and analgesic effects. Moreover, bee venom acupuncture has been commonly used for clinical disorders such as Parkinson disease, neuropathic pain, Alzheimer disease, intervertebral disc disease, spinal cord injury, musculoskeletal pain, arthritis, multiple sclerosis, skin disease and cancer.

Harnessing regulatory T cell neuroprotective activities for treatment of neurodegenerative disorders

Emerging evidence demonstrates that adaptive immunity influences the pathobiology of neurodegenerative disorders. Misfolded aggregated self-proteins can break immune tolerance leading to the induction of autoreactive effector T cells (Teffs) with associated decreases in anti-inflammatory neuroprotective regulatory T cells (Tregs). An imbalance between Teffs and Tregs leads to microglial activation, inflammation and neuronal injury. The cascade of such a disordered immunity includes the drainage of the aggregated protein antigens into cervical lymph nodes serving to amplify effector immune responses. Both preclinical and clinical studies demonstrate transformation of this altered immunity for therapeutic gain. We posit that the signs and symptoms of common neurodegenerative disorders such as Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, and stroke can be attenuated by boosting Treg activities.

Bee Venom Phospholipase A2 Induces Regulatory T Cell Populations by Suppressing Apoptotic Signaling Pathway

Bee venom phospholipase A2 is a lipolytic enzyme in bee venom that catalyzes hydrolysis of the sn-2 ester bond of membrane phospholipids to produce free fatty acid and lysophospholipids. Current evidence suggests that bee venom phospholipase A2 (bvPLA2) induces regulatory T cell expansion and attenuates several immune system-related diseases, including Alzheimer's disease. The induction of Treg cells is directly mediated by binding to mannose receptors on dendritic cells. This interaction induces the PGE2-EP2 signaling pathway, which promotes Treg induction in CD4⁺ T cells. In this study, we investigated the effects of bvPLA2 treatment on the apoptotic signaling pathway in Treg populations. Flow cytometry was performed to identify early apoptotic cells. As a result, early apoptotic cells were dramatically decreased in bvPLA2-treated splenocytes, whereas rapamycin-treated cells showed levels of apoptotic cells similar to those of PBS-treated cells. Furthermore, bvPLA2 treatment increased expression of anti-apoptotic molecules including CTLA-4 and PD-1. The survival rate increased in bvPLA2-treated Tregs. Our findings indicate that bvPLA2-mediated modulation of apoptotic signaling is strongly associated with the Treg induction, which exhibits protective effects against various immune-related diseases. To our knowledge, this study is the first to demonstrate that bvPLA2 is the major bee venom (BV) compound capable of inducing Treg expansion through altering apoptotic signal.

Amyloids in Site-Specific Autoimmune Reactions and Inflammatory Responses

Amyloid deposition is a histological hallmark of common human disorders including Alzheimer's disease (AD) and type 2 diabetes. Although some reports highlight that amyloid fibrils might activate the innate immunity system via pattern recognition receptors, here, we provide multiple lines of evidence for the protection by site-specific amyloid protein analogs and fibrils against autoimmune attacks: (1) strategies targeting clearance of the AD-related brain amyloid plaque induce high risk of deadly autoimmune destructions in subjects with cognitive dysfunction; (2) administration of amyloidogenic peptides with either full length or core hexapeptide structure consistently ameliorates signs of experimental autoimmune encephalomyelitis; (3) experimental autoimmune encephalomyelitis is exacerbated following genetic deletion of amyloid precursor proteins; (4) absence of islet amyloid coexists with T-cell-mediated insulitis in autoimmune diabetes and autoimmune polyendocrine syndrome; (5) use of islet amyloid polypeptide agonists rather than antagonists improves diabetes care; and (6) common suppressive signaling pathways by regulatory T cells are activated in both local and systemic amyloidosis. These findings indicate dual modulation activity mediated by amyloid protein monomers, oligomers, and fibrils to maintain immune homeostasis. The protection from autoimmune destruction by amyloid proteins offers a novel therapeutic approach to regenerative medicine for common degenerative diseases.

Bee Venom Soluble Phospholipase A2 Exerts Neuroprotective Effects in a Lipopolysaccharide-Induced Mouse Model of Alzheimer's Disease via Inhibition of Nuclear Factor-Kappa B

Neuroinflammation is important in the pathogenesis and development of Alzheimer's disease (AD). In the AD brain, microglial activation and upregulation of pro-inflammatory mediators both induce amyloid beta (Aβ) accumulation. Regulatory T cells (Tregs) and nuclear factor-kappa B (NF-κB) signaling have been implicated in AD development through their effects on neuroinflammation and microglial activation. The bee venom soluble phospholipase A2 (bv-sPLA2) enzyme is known to exert anti-inflammatory and anti-immune effects. Here, we investigated the inhibitory effects of bv-sPLA2 on memory deficiency in a lipopolysaccharide (LPS)-induced mouse model of AD. We examined whether bv-sPLA2 (0.02, 0.2, and 2 mg/kg by i.p. injection three times for 1 week) could inhibit neuroinflammation and memory impairment in LPS-treated mice (250 μg/kg by i.p. injection daily for 1 week). We also assessed the effects of bv-sPLA2 administration (0.01, 0.1, and 1 μg/ml) on LPS (1 μg/ml)-treated microglial BV-2 cells. In the LPS-injected mouse brain, sPLA2 treatment rescued memory dysfunction and decreased Aβ levels, through the downregulation of amyloidogenic proteins, and decreased the expression of inflammatory proteins and pro-inflammatory cytokines. Moreover, the LPS-mediated increase in inflammatory protein expression was attenuated bv-sPLA2 treatment in BV-2 cells. Treatment with bv-sPLA2 also downregulated signaling by NF-κB, which is considered to be an important factor in the regulation of neuroinflammatory and amyloidogenic responses, both in vivo and in vitro. Additionally, co-treatment with NF-κB (5 μM) and bv-sPLA2 (0.1 μg/ml) exerted more marked anti-inflammatory effects, compared to bv-sPLA2 treatment alone. These results indicate that bv-sPLA2 inhibits LPS-induced neuroinflammation and amyloidogenesis via inhibition of NF-κB.

Bee venom phospholipase A2 ameliorates amyloidogenesis and neuroinflammation through inhibition of signal transducer and activator of transcription-3 pathway in Tg2576 mice

Background

Neuroinflammation and accumulation of β-amyloid (Aβ) play a significant role in the onset and progression of Alzheimer’s disease (AD). Our previous study demonstrated that signal transducer and activator of transcription-3 (STAT3) plays a major role in neuroinflammation and amyloidogenesis.

Methods

In the present study, we investigated the inhibitory effect of bee venom phospholipase A2 (bvPLA2) on memory deficiency in Tg2576 mice, which demonstrate genetic characteristics of AD and the mechanism of its action at the cellular and animal level. For in vivo study, we examined the effect of bvPLA2 on improving memory by conducting several behavioral tests with the administration of bvPLA2 (1 mg/kg) to Tg2576 mice. For in vitro study, we examined the effect of bvPLA2 on amyloidogenesis and neuroinflammation by treating bvPLA2 on LPS-activated BV2 cells.

Results

We found that bvPLA2 alleviated memory impairment in Tg2576 mice, as demonstrated in the behavioral tests assessing memory. In the bvPLA2-treated group, Aβ, amyloid precursor protein (APP), and β-secretase 1 (BACE1) levels and β-secretase activity were significantly decreased. Expression of pro-inflammatory cytokines and inflammation-related proteins decreased in the brain of bvPLA2-treated group, whereas anti-inflammatory cytokines increased. In addition, bvPLA2 reduced STAT3 phosphorylation in the brains of the bvPLA2-treated group. At the cellular level, bvPLA2 inhibits production of nitric oxide, pro-inflammatory cytokines, and inflammation-related proteins including p-STAT3. Additionally, bvPLA2 inhibits the production of Aβ in cultured BV-2 cells. Results from the docking experiment, pull-down assay, and the luciferase assay show that bvPLA2 directly binds STAT3 and, thus, regulates gene expression levels. Moreover, when the STAT3 inhibitor and bvPLA2 were administered together, the anti-amyloidogenic and anti-inflammatory effects were further enhanced than when they were administered alone.

Conclusion

These results suggest that bvPLA2 could restore memory by inhibiting the accumulation of Aβ and inflammatory responses via blockage of STAT3 activity.

Electronic supplementary material

The online version of this article (10.1186/s40035-019-0167-7) contains supplementary material, which is available to authorized users.

Protective and Regenerative Roles of T Cells in Central Nervous System Disorders

Pathogenic mechanisms of T cells in several central nervous system (CNS) disorders are well-established. However, more recent studies have uncovered compelling beneficial roles of T cells in neurological diseases, ranging from tissue protection to regeneration. These divergent functions arise due to the diversity of T cell subsets, particularly CD4⁺ T cells. Here, we review the beneficial impact of T cell subsets in a range of neuroinflammatory and neurodegenerative diseases including multiple sclerosis, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, stroke, and CNS trauma. Both T cell-secreted mediators and direct cell contact-dependent mechanisms deliver neuroprotective, neuroregenerative and immunomodulatory signals in these settings. Understanding the molecular details of these beneficial T cell mechanisms will provide novel targets for therapeutic exploitation that can be applied to a range of neurological disorders.

Complementary and alternative medicine for treating amyotrophic lateral sclerosis: A narrative review

Background

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease that is characterized by selective motor neuron cell death in the motor cortex, brainstem, and spinal cord. Two drugs for ALS, riluzole and edaravone, have been approved by FDA for the treatment of ALS patients. However, they have many side effects, and riluzole extends the patient's life by only 2-3 months. Therefore, ALS patients seek an effective therapy for treating the symptoms or delaying the progression of ALS. Based on this, we review the effects of complementary and alternative medicine (CAM) in ALS animals or patients to verify the efficacy of CAM in incurable diseases. For this review, we searched published papers focusing on the effect of CAM in pre-clinical and clinical study in ALS.

Methods

The search keywords included amyotrophic lateral sclerosis, acupuncture, herbal medicine, Traditional Chinese medicine, CAM, animals, and clinical study through electronic databases PubMed and Google Scholar from their inception until March 2019.

Results

In the ALS animal model, CAM modulated the immune system to increase motor function by reducing the expression levels of neuroinflammatory proteins in the spinal cord. Besides this, ALS patients treated with herbal medicine showed improved disease symptoms, but clinical trials with larger sample sizes are needed to develop a treatment with this herbal medicine.

Conclusion

This review shows that CAM may be useful for ALS treatment, but more evidence regarding the efficacy and molecular mechanisms is required to establish CAM as a good therapy for the treatment of ALS patients.

Suppressive Effects of Bee Venom-Derived Phospholipase A2 on Mechanical Allodynia in a Rat Model of Neuropathic Pain

Bee venom (BV) has a long history of being used in traditional Korean medicine to relieve pain. Here, we investigated the effect of BV-derived phospholipase A2 (bvPLA2), a major component of BV, on peripheral nerve injury-induced neuropathic pain in rats. Spinal nerve ligation (SNL) was performed in Sprague Dawley rats to induce neuropathic pain, and paw withdrawal thresholds were measured using von Frey test. Mechanical allodynia, the representative symptom of neuropathic pain, was manifested following SNL and persisted for several weeks. The repetitive bvPLA2 treatment (0.2 mg/kg/day, i.p.) for two days significantly relieved the SNL-induced mechanical allodynia. The antiallodynic effect of bvPLA2 was blocked by spinal pretreatment with α1-adrenergic antagonist prazosin (30 μg, i.t.) but not with α2-adrenergic antagonist idazoxan (50 μg, i.t.). Also, the spinal application of α1-adrenergic agonist phenylephrine (50 μg, i.t.) reduced mechanical allodynia. These results indicate that bvPLA2 could relieve nerve injury-induced neuropathic mechanical allodynia through the activation of spinal α1-adrenergic receptors.

Bee Venom: Overview of Main Compounds and Bioactivities for Therapeutic Interests

Apitherapy is an alternate therapy that relies on the usage of honeybee products, most importantly bee venom for the treatment of many human diseases. The venom can be introduced into the human body by manual injection or by direct bee stings. Bee venom contains several active molecules such as peptides and enzymes that have advantageous potential in treating inflammation and central nervous system diseases, such as Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. Moreover, bee venom has shown promising benefits against different types of cancer as well as anti-viral activity, even against the challenging human immunodeficiency virus (HIV). Many studies described biological activities of bee venom components and launched preclinical trials to improve the potential use of apitoxin and its constituents as the next generation of drugs. The aim of this review is to summarize the main compounds of bee venom, their primary biological properties, mechanisms of action, and their therapeutic values in alternative therapy strategies.

A longitudinal multimodal in vivo molecular imaging study of the 3xTg-AD mouse model shows progressive early hippocampal and taurine loss

The understanding of the natural history of Alzheimer's disease (AD) and temporal trajectories of in vivo molecular mechanisms requires longitudinal approaches. A behavioral and multimodal imaging study was performed at 4/8/12 and 16 months of age in a triple transgenic mouse model of AD (3xTg-AD). Behavioral assessment included the open field and novel object recognition tests. Molecular characterization evaluated hippocampal levels of amyloid β (Aβ) and hyperphosphorylated tau. Magnetic resonance imaging (MRI) included assessment of hippocampal structural integrity, blood-brain barrier (BBB) permeability and neurospectroscopy to determine levels of the endogenous neuroprotector taurine. Longitudinal brain amyloid accumulation was assessed using 11C Pittsburgh compound B positron emission tomography (PET), and neuroinflammation/microglia activation was investigated using 11C-PK1195. We found altered locomotor activity at months 4/8 and 16 months and recognition memory impairment at all time points. Substantial early reduction of hippocampal volume started at month 4 and progressed over 8/12 and 16 months. Hippocampal taurine levels were significantly decreased in the hippocampus at months 4/8 and 16. No differences were found for amyloid and neuroinflammation with PET, and BBB was disrupted only at month 16. In summary, 3xTg-AD mice showed exploratory and recognition memory impairments, early hippocampal structural loss, increased Aβ and hyperphosphorylated tau and decreased levels of taurine. In sum, the 3xTg-AD animal model mimics pathological and neurobehavioral features of AD, with early-onset recognition memory loss and MRI-documented hippocampal damage. The early-onset profile suggests temporal windows and opportunities for therapeutic intervention, targeting endogenous neuroprotectors such as taurine.

Comparison of the Protective Effects of Bee Venom Extracts with Varying PLA2 Compositions in a Mouse Model of Parkinson's Disease

Bee venom contains a number of pharmacologically active components, including enzymes and polypeptides such as phospholipase A₂ (PLA₂) and melittin, which have been shown to exhibit therapeutic benefits, mainly via attenuation of inflammation, neurotoxicity, and nociception. The individual components of bee venom may manifest distinct biological actions and therapeutic potential. In this study, the potential mechanisms of action of PLA₂ and melittin, among different compounds purified from honey bee venom, were evaluated against Parkinson’s disease (PD). Notably, bee venom PLA₂ (bvPLA₂), but not melittin, exhibited neuroprotective activity against PD in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP-induced behavioral deficits were also abolished after bvPLA₂ treatment, depending on the PLA₂ content. Further, bvPLA₂ administration activated regulatory T cells (Tregs) while inhibiting inflammatory T helper (Th) 1 and Th17 cells in the MPTP mouse model of PD. These results indicate that bvPLA₂, but not melittin, protected against MPTP and alleviated inflammation in PD. Thus, bvPLA₂ is a promising and effective therapeutic agent in Parkinson’s disease.

Dose-Dependent Neuroprotective Effect of Standardized Bee Venom Phospholipase A2 Against MPTP-Induced Parkinson's Disease in Mice

Parkinson’s disease (PD) is a chronic progressive neurodegenerative movement disorder characterized by the selective loss of dopaminergic neurons within the substantia nigra (SN). While the precise etiology of dopaminergic neuronal demise is elusive, multiple lines of evidence indicate that neuroinflammation is involved in the pathogenesis of PD. We have previously demonstrated that subcutaneous administration of bee venom (BV) phospholipase A₂ (bvPLA₂) suppresses dopaminergic neuronal cell death in a PD mouse model. In the present study, we established standardized methods for producing bvPLA₂ agent isolated from crude BV at good manufacturing practice (GMP) facility. The therapeutic efficacy of purified bvPLA2 agent was examined in MPTP-induced PD mice. Importantly, administration of purified bvPLA₂ in a dose-dependent manner reversed motor deficits in PD mice as well as inhibited loss of dopaminergic neurons within the SN of PD mice. The concentration-dependent action of standardized bvPLA₂ appeared to be related to the induction of CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Tregs), which, in part, inhibits T helper 1 (Th1) and Th17 polarization and suppresses microglial activation in PD mice. Taken together, these results suggest that standardized bvPLA₂ purified from BV shows a neuroprotective effect against PD and thus has a potential target for treatment of PD.

L-Norvaline, a new therapeutic agent against Alzheimer's disease

Growing evidence highlights the role of arginase activity in the manifestation of Alzheimer’s disease (AD). Upregulation of arginase was shown to contribute to neurodegeneration. Regulation of arginase activity appears to be a promising approach for interfering with the pathogenesis of AD. Therefore, the enzyme represents a novel therapeutic target. In this study, we administered an arginase inhibitor, L-norvaline (250 mg/L), for 2.5 months to a triple-transgenic model (3×Tg-AD) harboring PS1M146V, APPSwe, and tauP301L transgenes. Then, the neuroprotective effects of L-norvaline were evaluated using immunohistochemistry, proteomics, and quantitative polymerase chain reaction assays. Finally, we identified the biological pathways activated by the treatment. Remarkably, L-norvaline treatment reverses the cognitive decline in AD mice. The treatment is neuroprotective as indicated by reduced beta-amyloidosis, alleviated microgliosis, and reduced tumor necrosis factor transcription levels. Moreover, elevated levels of neuroplasticity related postsynaptic density protein 95 were detected in the hippocampi of mice treated with L-norvaline. Furthermore, we disclosed several biological pathways, which were involved in cell survival and neuroplasticity and were activated by the treatment. Through these modes of action, L-norvaline has the potential to improve the symptoms of AD and even interferes with its pathogenesis. As such, L-norvaline is a promising neuroprotective molecule that might be tailored for the treatment of a range of neurodegenerative disorders. The study was approved by the Bar-Ilan University Animal Care and Use Committee (approval No. 82-10-2017) on October 1, 2017.

Bee venom phospholipase A2 ameliorates Alzheimer's disease pathology in Aβ vaccination treatment without inducing neuro-inflammation in a 3xTg-AD mouse model

Alzheimer’s disease (AD) is the most common form of dementia and is characterized by an imbalance between the production and clearance of amyloid-beta (Aβ) and tau proteins. Although vaccination against Aβ peptide results in a dramatic reduction in Aβ pathology in experimental mouse models, the initial clinical trial for an active Aβ vaccine was halted early due to the development of acute meningoencephalitis in 6% of the immunized patients, which likely involved a T-cell mediated pro-inflammatory response. In this study, we aimed to determine whether bee venom phospholipase A2 (bvPLA2) treatment would induce Tregs and ameliorate AD pathology without unwanted T cell-mediated inflammation. First, we investigated the effects of bvPLA2 on the inflammatory infiltration caused by Aβ vaccination. Inflammatory aggregates of CD3⁺ T lymphocytes and macrophages were found in the brains and spinal cords of mice treated with Aβ. However, administration of bvPLA2 dramatically eliminated central nervous system inflammation following Aβ immunization. In AD model mice (3xTg-AD mice), bvPLA2 administration significantly ameliorated cognitive deficits and reduced Aβ burdens in the brains of Aβ-vaccinated 3xTg-AD mice. Additionally, we examined brain glucose metabolism using positron emission tomography with ¹⁸F-2 fluoro-2-deoxy-d-glucose. Cerebral glucose uptake was considerably higher in the brains of Aβ-vaccinated 3xTg-AD mice that received bvPLA2 than those that did not. The present study suggests that the modulation of Treg populations via bvPLA2 treatment may be a new therapeutic approach to attenuate the progression of AD in conjunction with Aβ vaccination therapy without an adverse inflammatory response.

Immunology of Bee Venom

Bee venom is a blend of biochemicals ranging from small peptides and enzymes to biogenic amines. It is capable of triggering severe immunologic reactions owing to its allergenic fraction. Venom components are presented to the T cells by antigen-presenting cells within the skin. These Th2 type T cells then release IL-4 and IL-13 which subsequently direct B cells to class switch to production of IgE. Generating venom-specific IgE and crosslinking FcεR1(s) on the surface of mast cells complete the sensitizing stage in allergic individuals who are most likely to experience severe and even fatal allergic reactions after being stung. Specific IgE for bee venom is a double-edged sword as it is a powerful mediator in triggering allergic events but is also applied successfully in diagnosis of the venom allergic patient. The healing capacity of bee venom has been rediscovered under laboratory-controlled conditions using animal models and cell cultures. The potential role of enzymatic fraction of bee venom including phospholipase A2 in the initiation and development of immune responses also has been studied in numerous research settings. Undoubtedly, having insights into immunologic interactions between bee venom components and innate/specific immune cells both locally and systematically will contribute to the development of immunologic strategies in specific and epitope-based immunotherapy especially in individuals with Hymenoptera venom allergy.

Granulocyte-macrophage colony-stimulating factor neuroprotective activities in Alzheimer's disease mice

We investigated the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on behavioral and pathological outcomes in Alzheimer's disease (AD) and non-transgenic mice. GM-CSF treatment in AD mice reduced brain amyloidosis, increased plasma Aβ, and rescued cognitive impairment with increased hippocampal expression of calbindin and synaptophysin and increased levels of doublecortin-positive cells in the dentate gyrus. These data extend GM-CSF pleiotropic neuroprotection mechanisms in AD and include regulatory T cell-mediated immunomodulation of microglial function, Aβ clearance, maintenance of synaptic integrity, and induction of neurogenesis. Together these data support further development of GM-CSF as a neuroprotective agent for AD.

Comparison of Administration Routes on the Protective Effects of Bee Venom Phospholipase A2 in a Mouse Model of Parkinson's Disease

Parkinson’s disease (PD) is the second most common neurodegenerative disorder worldwide. Progressive loss of dopaminergic neurons in the substantia nigra (SN) and their synaptic terminal connections in the striatum are main characterizations of PD. Although many efforts have been made to develop therapeutics, no treatment has been proven effective. We previously demonstrated that bvPLA2 can protect dopaminergic neurons by modulating neuroinflammatory responses in an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced mouse model of PD. The cellular basis for the neuroprotective response of bvPLA2 was the induction of CD4⁺CD25⁺ regulatory T cells (Tregs), a population known to suppress immune activation and maintain homeostasis and tolerance to self-antigen. The aim of the present study was to investigate the effects of different routes of bvPLA2 administration in a PD mouse model. Neurobehavioral assessment revealed progressive deterioration in locomotor functions of the MPTP group compared with the control group. However, such functions were improved following subcutaneous (s.c.) bvPLA2 administration. The results showed that the s.c. route of bvPLA2 administration contributed to the induction of Treg cells and the reduction of Th1 and Th17 populations, demonstrating that the neuroprotective effects were associated with reduced tyrosine hydroxylase (TH)-positive dopaminergic neurons and microglia. These results suggested that the s.c. bvPLA2 injection could be beneficial for treating aspects of PD.

Effect of Chronic Oxidative Stress on Neuroinflammatory Response Mediated by CD4+T Cells in Neurodegenerative Diseases

In a state of oxidative stress, there is an increase of reactive species, which induce an altered intracellular signaling, leading to dysregulation of the inflammatory response. The inability of the antioxidant defense systems to modulate the proinflammatory response is key to the onset and progression of neurodegenerative diseases. The aim of this work is to review the effect of the state of oxidative stress on the loss of regulation of the inflammatory response on the microglia and astrocytes, the induction of different CD4⁺T cell populations in neuroinflammation, as well as its role in some neurodegenerative diseases. For this purpose, an intentional search of original articles, short communications, and reviews, was carried out in the following databases: PubMed, Scopus, and Google Scholar. The articles reviewed included the period from 1997 to 2017. With the evidence obtained, we conclude that the loss of redox balance induces alterations in the differentiation and number of CD4⁺T cell subpopulations, leading to an increase in Th1 and Th17 response. This contributes to the development of neuroinflammation as well as loss of the regulation of the inflammatory response in neurodegenerative diseases such as Alzheimer's (AD), Parkinson's (PD), and Multiple Sclerosis (MS). In contrast, regulatory T cells (Tregs) and Th2 modulate the inflammatory response of effect of T cells, microglia, and astrocytes. In this respect, it has been found that the mobilization of T cells with anti-inflammatory characteristics toward damaged regions of the CNS can provide neuroprotection and become a therapeutic strategy to control inflammatory processes in neurodegeneration.

Bee venom therapy: Potential mechanisms and therapeutic applications

Bee venom is a very complex mixture of natural products extracted from honey bee which contains various pharmaceutical properties such as peptides, enzymes, biologically active amines and nonpeptide components. The use of bee venom into the specific points is so called bee venom therapy, which is widely used as a complementary and alternative therapy for 3000 years. A growing number of evidence has demonstrated the anti-inflammation, the anti-apoptosis, the anti-fibrosis and the anti-arthrosclerosis effects of bee venom therapy. With these pharmaceutical characteristics, bee venom therapy has also been used as the therapeutic method in treating rheumatoid arthritis, amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, liver fibrosis, atherosclerosis, pain and others. Although widely used, several cases still reported that bee venom therapy might cause some adverse effects, such as local itching or swelling. In this review, we summarize its potential mechanisms, therapeutic applications, and discuss its existing problems.

Animal Toxins as Therapeutic Tools to Treat Neurodegenerative Diseases

Neurodegenerative diseases affect millions of individuals worldwide. So far, no disease-modifying drug is available to treat patients, making the search for effective drugs an urgent need. Neurodegeneration is triggered by the activation of several cellular processes, including oxidative stress, mitochondrial impairment, neuroinflammation, aging, aggregate formation, glutamatergic excitotoxicity, and apoptosis. Therefore, many research groups aim to identify drugs that may inhibit one or more of these events leading to neuronal cell death. Venoms are fruitful natural sources of new molecules, which have been relentlessly enhanced by evolution through natural selection. Several studies indicate that venom components can exhibit selectivity and affinity for a wide variety of targets in mammalian systems. For instance, an expressive number of natural peptides identified in venoms from animals, such as snakes, scorpions, bees, and spiders, were shown to lessen inflammation, regulate glutamate release, modify neurotransmitter levels, block ion channel activation, decrease the number of protein aggregates, and increase the levels of neuroprotective factors. Thus, these venom components hold potential as therapeutic tools to slow or even halt neurodegeneration. However, there are many technological issues to overcome, as venom peptides are hard to obtain and characterize and the amount obtained from natural sources is insufficient to perform all the necessary experiments and tests. Fortunately, technological improvements regarding heterologous protein expression, as well as peptide chemical synthesis will help to provide enough quantities and allow chemical and pharmacological enhancements of these natural occurring compounds. Thus, the main focus of this review is to highlight the most promising studies evaluating animal toxins as therapeutic tools to treat a wide variety of neurodegenerative conditions, including Alzheimer’s disease, Parkinson’s disease, brain ischemia, glaucoma, amyotrophic lateral sclerosis, and multiple sclerosis.

Peripheral Lymphocyte Subsets as a Marker of Parkinson's Disease in a Chinese Population

In this study, we conducted a clinical analysis of lymphocyte subtypes in 268 patients with Parkinson's disease (PD) to assess their clinical impact as a potential marker of advanced PD in Chinese patients. The participants comprised 268 sporadic PD patients and 268 healthy controls. The numbers of natural killer (NK) cells and CD3+, CD3+CD4+, CD3+CD8+, and CD19+ lymphocytes from peripheral blood were determined by immunostaining and flow cytometric analysis and the percentages of these CD+ T cells were calculated. The ratio of regulatory T (Treg)/helper T 17 (Th17) lymphocytes from 64 PD patients and 46 controls was determined by flow cytometric analysis. The results showed that the percentage of NK cells was higher in advanced PD patients than in controls (22.92% ± 10.08% versus 19.76% ± 10.09%, P = 0.006), while CD3+ T cells are decreased (62.93% ± 9.27% versus 65.75% ± 9.13%, P = 0.005). The percentage of CD19+ B cells in male patients was lower (P = 0.021) than in female patients, whereas NK cells were increased (P < 0.0001). The scores on the Unified Parkinson's Disease Rating Scale (UPDRS) and the Non-Motor Symptoms Scale in late-onset PD patients were significantly higher than those in early-onset patients (P = 0.024 and P = 0.007, respectively). The percentage of CD19+ B cells in patients with UPDRS scores >24 was lower than in those with scores <24 (10.17% ± 4.19% versus 12.22% ± 5.39%, P = 0.009). In addition, the Treg/Th17 ratio in female patients was higher than that in female controls (13.88 ± 6.32 versus 9.94 ± 4.06, P = 0.042). These results suggest that the percentages of NK cells, CD3+ T cells, and CD19+ B cells along with the Treg/Th17 ratio in peripheral blood may be used to predict the risk of PD in Chinese individuals and provide fresh avenues for novel diagnostic biomarkers and therapeutic designs.