Rg3-enriched Korean Red Ginseng extract inhibits blood-brain barrier disruption in an animal model of multiple sclerosis by modulating expression of NADPH oxidase 2 and 4

Exploring the Potential Therapeutic Approach Using Ginsenosides for the Management of Neurodegenerative Disorders

There is a need for an efficient and long-lasting treatment due to the population's increasing prevalence of neurodegenerative disorders. In an effort to generate fresh ideas and create novel therapeutic medications, scientists have recently started to investigate the biological functions of compounds derived from plants and herbs. Ginseng, famous Chinese herbal medicine, has therapeutic value by virtue of its compounds ginsenosides or panaxosides, which are triterpene saponins and steroid glycosides. Research revealed positive impacts on ameliorating various disease conditions and found it as a possible drug candidate. Several neuroprotection mechanisms followed by this compound are inhibition of cell apoptosis, oxidative stress, inflammatory, and tumor activity. It has been demonstrated that controlling these mechanisms enhances cognitive performance and safeguards the brain against neurodegenerative disorders. The main objective of this review is to give a description of the most recent studies on ginsenoside's possible therapeutic application in the treatment of neurodegenerative diseases. Using organic compounds like ginseng and its various components may create new avenues for innovative treatment approaches development for neurological diseases. However, further research is necessary to confirm the stability and effectiveness of ginsenosides for neurodegenerative disease.

Ginsenoside-Re inhibits experimental autoimmune encephalomyelitis as a mouse model of multiple sclerosis by downregulating TLR4/MyD88/NF-κB signaling pathways

BACKGROUND

Ginsenosides are main active compounds of Panax ginseng with pharmacological effects on immunological/neurological diseases. Recently, ginsenoside-Re (G-Re) has been shown to exert neuroprotective effects on neurodegenerative diseases such as Alzheimer's disease. However, whether G-Re has an effect on multiple sclerosis (MS), a representative autoimmune disease of the central nervous system (CNS), has not been revealed yet.

PURPOSE AND METHODS

The purpose of this study was to investigate pharmacological effects of G-Re and related molecular mechanisms using a myelin oligodendrocyte glycoprotein peptide-immunized experimental autoimmune encephalomyelitis (EAE) animal model of MS and lipopolysaccharide (LPS)-stimulated bEND.3 cells as an in vitro model of the blood-brain barrier (BBB).

RESULTS

G-Re attenuated motor impairment of EAE, demyelination, and inflammation in spinal cords of EAE mice. G-Re reduced infiltration/activation of microglia/macrophages and decreased mRNA expression levels of pro-inflammatory cytokines (IL-1β and IL-6), chemokines (MIP-1α, MCP-1, and RANTES), and enzymes (iNOS) in spinal cords of EAE mice. G-Re inhibited alterations of BBB constituents (such as astrocytes, cell adhesion molecule (platelet endothelial cell adhesion molecule-1), and tight junctional molecules (occludin and zonula occludens-1)) and toll like receptor 4 (TLR4)/MyD88/nuclear factor kappa-B (NF-κB) signaling pathways in spinal cords of EAE mice and LPS-stimulated bEND.3 cells. Interestingly, combination treatment with G-Re and TLR4 inhibitor (TAK242) significantly inhibited the upregulation of TLR4/MyD88/NF-κB pathway in LPS-stimulated bEND.3 cells. TLR4 inhibitor- and activator-treated EAE mice showed conflicting behavior patterns.

CONCLUSION

G-Re might alleviate motor impairment of EAE and its pathological/inflammatory events in the spinal cord by preventing BBB disruption via downregulation of TLR4/MyD88/NF-κB signaling pathways. These findings for the first time suggest that G-Re might be a potential therapeutic for MS through maintenance of BBB integrity.

Protective effect of exogenous peroxiredoxin 6 and thymic peptide thymulin on BBB conditions in an experimental model of multiple sclerosis

This study aimed to assess the effects of the immunomodulator thymulin, a thymic peptide with anti-inflammatory effects, and peroxiredoxin 6 (Prdx6), an antioxidant enzyme with dual peroxidase and phospholipase A2 activities, on the blood‒brain barrier (BBB) condition and general health status of animals with relapsing-remitting experimental autoimmune encephalomyelitis (EAE), which is a model of multiple sclerosis in humans. Both thymulin and Prdx6 significantly improved the condition of the BBB, which was impaired by EAE induction, as measured by Evans blue dye accumulation, tight-junction protein loss in brain tissue, and lymphocyte infiltration through the BBB. The effect was associated with significant amelioration of EAE symptoms. Thymulin treatment was accompanied by a decrease in immune cell activation as judged by interleukin-6, -17, and interferon-gamma cytokine levels in serum and NF-kappaB cascade activation in splenocytes of mice with EAE. Prdx6 did not induce significant immunomodulatory effects but abruptly decreased EAE-induced NOX1 and NOX4 gene expression in brain tissue, which may be one of the possible mechanisms of its beneficial effects on BBB conditions and health status. The simultaneous administration of thymulin and Prdx6 resulted in complete symptomatic restoration of mice with EAE. The results demonstrate prospective strategies for multiple sclerosis treatment.

Retinal cell-targeted liposomal ginsenoside Rg3 attenuates retinal ischemia-reperfusion injury via alleviating oxidative stress and promoting microglia/macrophage M2 polarization

Retinal ischemia-reperfusion (RIR) injury remains a major challenge that is detrimental to retinal cell survival in a variety of ocular diseases. However, current clinical treatments focus on a single pathological mechanism, making them unable to provide comprehensive retinal protection. A variety of natural products including ginsenoside Rg3 (Rg3) exhibit potent antioxidant and anti-inflammatory activities. Unfortunately, the hydrophobicity of Rg3 and the presence of various intraocular barriers limit its effective application in clinical settings. Hyaluronic acid (HA)- specifically binds to cell surface receptors, CD44, which is widely expressed in retinal pigment epithelial cells and M1-type macrophage. Here, we developed HA-decorated liposomes loaded with Rg3, termed Rg3@HA-Lips, to protect against retinal damage caused by RIR injury. Treatment with Rg3@HA-Lips significantly inhibited the oxidative stress induced by RIR injury. In addition, Rg3@HA-Lips promoted the transition of M1-type macrophage to the M2 type, ultimately reversing the pro-inflammatory microenvironment. The mechanism of Rg3@HA-Lips was further investigated and found that they can regulateSIRT/FOXO3a, NF-κB and STAT3 signaling pathways. Together with as well demonstrated good safety profiles, this CD44-targeted platform loaded with a natural product alleviates RIR injury by modulating the retinal microenvironment and present a potential clinical treatment strategy.

Neuroprotective effects of bornyl acetate on experimental autoimmune encephalomyelitis via anti-inflammatory effects and maintaining blood-brain-barrier integrity

BACKGROUND

Bornyl acetate (BA), a chemical component of essential oil in the Pinus family, has yet to be actively studies in terms of its therapeutic effect on numerous diseases, including autoimmune diseases.

PURPOSE

This study aimed to investigate the pharmacological effects and molecular mechanisms of BA on myelin oligodendrocyte glycoprotein (MOG_35-55)-induced experimental autoimmune encephalomyelitis (EAE) mice in an animal model of multiple sclerosis (MS), a representative autoimmune disease in central nervous system.

METHODS

BA (100, 200, or 400 mg/kg) was orally treated to EAE mice once daily for 30 days after immunization for the behavioral test and for the 16th-18th days for the histopathological and molecular analyses, from the onset stage (8th day) of EAE symptoms.

RESULTS

BA mitigated behavioral dysfunction (motor disability) and demyelination in the spinal cord that were associated with the down-regulation of representative pro-inflammatory cytokines (interleukin (IL)-1 beta, IL-6, and tumor necrosis factor-alpha), enzymes (cyclooxygenase-2 and inducible nitric oxide synthase), and chemokines (monocyte chemotactic protein-1, macrophage inflammatory protein-1 alpha, and regulated on activation), and decreased infiltration of microglia (CD11b⁺/CD45^+(low)) and macrophages (CD11b⁺/CD45^+(high)). The anti-inflammatory effect of BA was related to the inhibition of mitogen-activated protein kinases and nuclear factor-kappa B pathways. BA also reduced the recruitment/infiltration rates of CD4⁺ T, Th1, and Th17 cells into the spinal cords of EAE mice, which was related to reduced blood-spinal cord barrier (BSCB) disruption.

CONCLUSION

These findings strongly suggest that BA may alleviate EAE due to its anti-inflammatory and BSCB protective activities. This indicates that BA is a potential therapeutic agent for treating autoimmune demyelinating diseases including MS.

Ginsenosides from Panax ginseng as Key Modulators of NF-κB Signaling Are Powerful Anti-Inflammatory and Anticancer Agents

Nuclear factor kappa B (NF-κB) signaling pathways progress inflammation and immune cell differentiation in the host immune response; however, the uncontrollable stimulation of NF-κB signaling is responsible for several inflammatory illnesses regardless of whether the conditions are acute or chronic. Innate immune cells, such as macrophages, microglia, and Kupffer cells, secrete pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-1β, via the activation of NF-κB subunits, which may lead to the damage of normal cells, including neurons, cardiomyocytes, hepatocytes, and alveolar cells. This results in the occurrence of neurodegenerative disorders, cardiac infarction, or liver injury, which may eventually lead to systemic inflammation or cancer. Recently, ginsenosides from Panax ginseng, a historical herbal plant used in East Asia, have been used as possible options for curing inflammatory diseases. All of the ginsenosides tested target different steps of the NF-κB signaling pathway, ameliorating the symptoms of severe illnesses. Moreover, ginsenosides inhibit the NF-κB-mediated activation of cancer metastasis and immune resistance, significantly attenuating the expression of MMPs, Snail, Slug, TWIST1, and PD-L1. This review introduces current studies on the therapeutic efficacy of ginsenosides in alleviating NF-κB responses and emphasizes the critical role of ginsenosides in severe inflammatory diseases as well as cancers.

Natural products targeting cellular processes common in Parkinson's disease and multiple sclerosis

The hallmarks of Parkinson's disease (PD) include the loss of dopaminergic neurons and formation of Lewy bodies, whereas multiple sclerosis (MS) is an autoimmune disorder with damaged myelin sheaths and axonal loss. Despite their distinct etiologies, mounting evidence in recent years suggests that neuroinflammation, oxidative stress, and infiltration of the blood-brain barrier (BBB) all play crucial roles in both diseases. It is also recognized that therapeutic advances against one neurodegenerative disorder are likely useful in targeting the other. As current drugs in clinical settings exhibit low efficacy and toxic side effects with long-term usages, the use of natural products (NPs) as treatment modalities has attracted growing attention. This mini-review summarizes the applications of natural compounds to targeting diverse cellular processes inherent in PD and MS, with the emphasis placed on their neuroprotective and immune-regulating potentials in cellular and animal models. By reviewing the many similarities between PD and MS and NPs according to their functions, it becomes evident that some NPs studied for one disease are likely repurposable for the other. A review from this perspective can provide insights into the search for and utilization of NPs in treating the similar cellular processes common in major neurodegenerative diseases.

Rg3-enriched Korean red ginseng alleviates chloroquine-induced itch and dry skin pruritus in an MrgprA3-dependent manner in mice

Background

Previous studies have found that Korean red ginseng extract (KRG) has antipruritic effects, which can be attributed to the presence of Rg3, one of the most potent ginsenosides. Therefore, Rg3-enriched KRG extract (Rg3EKRG) is anticipated to have enhanced antipruritic effects. The present study was conducted to examine the effects of Rg3EKRG in acute chloroquine (CQ)-induced and chronic dry skin pruritus.

Methods

Calcium imaging technique was used in HE293T cells expressing MrgprA3 and TRPA1 ("MrgprA3/TRPA1") and in primary cultures of mouse dorsal root ganglia (DRG) neurons. Mouse scratching behavior tests were performed on dry skin models. To verify the altered expression of itch-related genes, real-time RNA sequencing analysis and PCR were performed on DRG sections obtained from dry skin models.

Results

Rg3EKRG suppressed CQ-induced intracellular calcium changes to a greater degree than KRG. Rg3EKRG dose-dependently inhibited CQ-induced responses in MrgprA3/TRPA1 cells. Rg3EKRG likely targeted MrgprA3 rather than TRPA1 to exert its inhibitory effect. Further, Rg3EKRG strongly inhibited the scratching behavior in mice induced by acute CQ injection. Importantly, DRG neurons obtained from dry skin mice models showed increased mRNA levels of MrgprA3, and treatment with Rg3EKRG alleviated chronic dry skin conditions and suppressed spontaneous scratching behaviors.

Conclusion

The results of the present study imply that Rg3EKRG has a stronger antipruritic effect than KRG, inhibiting both acute CQ-induced and chronic dry skin pruritus in an MrgprA3-dependent manner. Therefore, Rg3EKRG is a potential antipruritic agent that can suppress acute and chronic itching at the peripheral sensory neuronal level.

The Role of Thymoquinone in Inflammatory Response in Chronic Diseases

Anti-inflammatory therapies have been shown to be effective in the prevention of various cardiovascular diseases, tumors, and cancer complications. Thymoquinone (TQ), the main active constituent of Nigella sativa, has shown promising therapeutic properties in many in vivo and in vitro models. However, TQ has poor bioavailability and is hydrophobic, prohibiting clinical trials with TQ alone. Studies have explored the combination of TQ with biological nanomaterials to improve its bioavailability. The TQ nanoparticle formulation shows better bioavailability than free TQ, and these formulations are ready for clinical trials to determine their potential as therapeutic agents. In this paper, we review current knowledge about the interaction between TQ and the inflammatory response and summarize the research prospects in Korea and abroad. We discuss the different biological activities of TQ and various combination therapies of TQ and nanomaterials in clinical trials.

Potential Utility of Natural Products against Oxidative Stress in Animal Models of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune-mediated degenerative disease of the central nervous system (CNS) characterized by immune cell infiltration, demyelination and axonal injury. Oxidative stress-induced inflammatory response, especially the destructive effect of immune cell-derived free radicals on neurons and oligodendrocytes, is crucial in the onset and progression of MS. Therefore, targeting oxidative stress-related processes may be a promising preventive and therapeutic strategy for MS. Animal models, especially rodent models, can be used to explore the in vivo molecular mechanisms of MS considering their similarity to the pathological processes and clinical signs of MS in humans and the significant oxidative damage observed within their CNS. Consequently, these models have been used widely in pre-clinical studies of oxidative stress in MS. To date, many natural products have been shown to exert antioxidant effects to attenuate the CNS damage in animal models of MS. This review summarized several common rodent models of MS and their association with oxidative stress. In addition, this review provides a comprehensive and concise overview of previously reported natural antioxidant products in inhibiting the progression of MS.

Ginsenosides in central nervous system diseases: Pharmacological actions, mechanisms, and therapeutics

The nervous system is one of the most complex physiological systems, and central nervous system diseases (CNSDs) are serious diseases that affect human health. Ginseng (Panax L.), the root of Panax species, are famous Chinese herbs that have been used for various diseases in China, Japan, and Korea since ancient times, and remain a popular natural medicine used worldwide in modern times. Ginsenosides are the main active components of ginseng, and increasing evidence has demonstrated that ginsenosides can prevent CNSDs, including neurodegenerative diseases, memory and cognitive impairment, cerebral ischemia injury, depression, brain glioma, multiple sclerosis, which has been confirmed in numerous studies. Therefore, this review summarizes the potential pathways by which ginsenosides affect the pathogenesis of CNSDs mainly including antioxidant effects, anti-inflammatory effects, anti-apoptotic effects, and nerve protection, which provides novel ideas for the treatment of CNSDs.