Korean Red Ginseng attenuates ultraviolet-mediated inflammasome activation in keratinocytes

Maltol, a compound in Korean Red Ginseng, attenuates the Staphylococcus aureus-induced inflammasome activation in the skin

Background

Staphylococcus aureus can cause local or systemic infections as an opportunistic pathogen and induce the activation of inflammasomes, leading to the secretion of interleukin (IL)-1β. Since S. aureus is part of the normal flora, it is essential to control it using safe, non-antibiotic substances like Korean Red Ginseng Extract (RGE). This study investigated the effects of maltol, a non-saponin compound found in RGE, on S. aureus-mediated inflammasome signaling.

Methods

Human keratinocytes (HaCaT) and macrophages were infected with S. aureus and treated with RGE and maltol. The secretion of IL-1β, an indicator of inflammasome activation, was analyzed. For the mechanistic studies, the HaCaT cells were infected with S. aureus in the presence of maltol or inflammasome inhibitors, and the generation of mitochondrial reactive oxygen species (mitROS) and IL-1β production were measured. The effect of maltol was also evaluated in S. aureus-injected mice.

Results

RGE and maltol inhibited S. aureus-mediated IL-1β secretion in HaCaT, but not in macrophages. In the mechanistic studies, maltol suppressed the production of mitROS and the priming step of inflammasome signaling resulting in attenuated S. aureus-mediated inflammasome activation in HaCaT. In mice, maltol inhibited the production of peritoneal IL-1β and IL-6 in response to the S. aureus injection.

Conclusion

Maltol selectively regulated skin inflammasome activation by inhibiting mitROS generation and the inflammasome priming step.

Therapeutic Potential of Natural Resources Against Endometriosis: Current Advances and Future Perspectives

Endometriosis (EMS) is defined as the appearance, growth, infiltration, and repeated bleeding of endometrioid tissue (glands and stroma) outside the uterus cavity, which can form nodules and masses. Endometriosis is a chronic inflammatory estrogen-dependent disease and occurs in women of reproductive age. This disorder may significantly affect the quality of life of patients. The pathogenic processes involved in the development and maintenance of endometriosis remain unclear. Current treatment options for endometriosis mainly include drug therapy and surgery. Drug therapy mainly ties to the use of non-steroidal anti-inflammatory drugs (NSAIDs) and hormonal drugs. However, these drugs may produce adverse effects when used for long-term treatment of endometriosis, such as nausea, vomiting gastrointestinal reactions, abnormal liver and kidney function, gastric ulcers, and thrombosis. Although endometriosis lesions can be surgically removed, the disease has a high recurrence rate after surgical resection, with a recurrence rate of 21.5% within 2 years and 40% to 50% within 5 years. Thus, there is an urgent need to develop alternative or additional therapies for the treatment of endometriosis. In this review, we give a systematic summary of therapeutic multiple component prescriptions (including traditional Chinese medicine and so on), bioactive crude extracts of plants/herbs and purified compounds and their newly found mechanisms reported in literature in recent years against endometriosis.

Combination of red ginseng and velvet antler extracts prevents skin damage by enhancing the antioxidant defense system and inhibiting MAPK/AP-1/NF-κB and caspase signaling pathways in UVB-irradiated HaCaT keratinocytes and SKH-1 hairless mice

Background

Studies have reported that the combination of two or more therapeutic compounds at certain ratios has more noticeable pharmaceutical properties than single compounds and requires reduced dosage of each agent. Red ginseng and velvet antler have been extensively used in boosting immunity and physical strength and preventing diseases. Thus, this study was conducted to elucidate the skin-protective potentials of red ginseng extract (RGE) and velvet antler extract (VAE) alone or in combination on ultraviolet (UVB)-irradiated human keratinocytes and SKH-1 hairless mice.

Methods

HaCaT cells were preincubated with RGE/VAE alone or in combination for 2 h before UVB (30 mJ/cm2) irradiation. SKH-1 mice were orally given RGE/VAE alone or in combination for 15 days before exposure to single dose of UVB (600 mJ/cm2). Treated cells and treated skin tissues were collected and subjected to subsequent experiments.

Results

RGE/VAE pretreatment alone or in combination significantly prevented UVB-induced cell death, apoptosis, reactive oxygen species production, and DNA damage in keratinocytes and SKH-1 mouse skins by downregulating mitogen-activated protein kinases/activator protein 1/nuclear factor kappa B and caspase signaling pathways. These extracts also strengthened the antioxidant defense systems and skin barriers in UVB-irradiated HaCaT cells and SKH-1 mouse skins. Furthermore, RGE/VAE co-administration appeared to be more effective in preventing UVB-caused skin injury than these extracts used alone.

Conclusion

Overall, these findings suggest that the consumption of RGE/VAE, especially in combination, offers a protective ability against UVB-caused skin injury by preventing inflammation and apoptosis and enhancing antioxidant capacity.

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.

Antitumor Effect of Korean Red Ginseng through Blockade of PD-1/PD-L1 Interaction in a Humanized PD-L1 Knock-In MC38 Cancer Mouse Model

Blocking immune checkpoints, programmed death-1 (PD-1) and its ligand PD-L1, has proven a promising anticancer strategy for enhancing cytotoxic T cell activity. Although we previously demonstrated that ginsenoside Rg3, Rh2, and compound K block the interaction of PD-1 and PD-L1, the antitumor effect through blockade of this interaction by Korean Red Ginseng alone is unknown. Therefore, we determined the effects of Korean Red Ginseng extract (RGE) on the PD-1/PD-L1 interaction and its antitumor effects using a humanized PD-1/PD-L1-expressing colorectal cancer (CRC) mouse model. RGE significantly blocked the interaction between human PD-1 and PD-L1 in a competitive ELISA. The CD8⁺ T cell-mediated tumor cell killing effect of RGE was evaluated using murine hPD-L1-expressing MC38 cells and tumor-infiltrating hPD-1-expressing CD8⁺ T cells isolated from hPD-L1 MC38 tumor-bearing hPD-1 mice. RGE also reduced the survival of hPD-L1 MC38 cells in a cell co-culture system using tumor-infiltrating CD8⁺ T cells as effector cells combined with hPD-L1 MC38 target cells. RGE or Keytruda (positive control) treatment markedly suppressed the growth of hPD-L1 MC38 allograft tumors, increased CD8⁺ T cell infiltration into tumors, and enhanced the production of Granzyme B. RGE exhibits anticancer effects through the PD-1/PD-L1 blockade, which warrants its further development as an immunotherapy.

Ginseng-derived nanoparticles induce skin cell proliferation and promote wound healing

Background

Past studies suggested that ginseng extracts and ginseng-derived molecules exerted significant regulatory effects on skin. However, no reports have described the effects of ginseng-derived nanoparticles (GDNPs) on skin cell proliferation and wound healing. In this study, we investigated whether GDNPs regulate the proliferation of skin cells and promote wound healing in a mouse model.

Methods

GDNPs were separated and purified via differential centrifugation and sucrose/D2O gradient ultracentrifugation. GDNP uptake, cell proliferation and cell cycle progression were measured by confocal microscopy, CCK-8 assay and flow cytometry, respectively. Cell migration and angiogenic effects were assessed by the wound scratch assay and tube formation assay, respectively. ELISA was used to detect extracellular matrix secretion. The relevant signaling pathway was confirmed by western blotting. The effects of GDNPs on skin wound healing were assessed by wound observation, HE staining, and western blotting.

Results

GDNPs possessed the essential features of exosomes, and they were accumulated by skin cells. Treatment with GDNPs notably enhanced the proliferation of HaCaT, BJ and HUVECs. GDNPs also enhanced the migration in HaCaT cells and HUVECs and angiogenesis in HUVECs. GDNPs increased the secretion of MMP-1, fibronectin-1, elastin-1, and COL1A1 in all three cell lines. GDNPs regulated cell proliferation through the ERK and AKT/ mTOR pathways. Furthermore, GDNPs facilitated skin wound healing and decreased inflammation in a mouse skin wound model.

Conclusion

GDNPs can promote skin wound healing through the ERK and AKT/mTOR pathways. GDNPs thus represent an alternative treatment for chronic skin wounds.

JC2-11, a benzylideneacetophenone derivative, attenuates inflammasome activation

Dysregulation of inflammasome activation induces chronic and excess inflammation resulting in several disorders, such as metabolic disorders and cancers. Thus, screening for its regulator derived from natural materials has been conducted progressively. JC2-11 (JC) was designed to enhance the antioxidant activity based on a chalcone, which is abundant in edible plants and a precursor of flavonoids. This study examined the effects of JC on inflammasome activation in human and murine macrophages. JC inhibited the secretion of interleukin (IL)-1β and lactate dehydrogenases, and the cleavage of caspase-1 and gasdermin D in response to the tested activators (i.e., NLRP3, NLRC4, AIM2, and non-canonical inflammasome triggers). In addition, JC attenuated IL-1β secretion from lipopolysaccharide (LPS)-injected mice, an inflammasome-mediating disease model. Mechanistically, JC blocked the expression of the inflammasome components during the priming step of the inflammasome, and interrupted the production of mitochondrial reactive oxygen species. In addition, JC inhibited the activity of caspase-1. In conclusion, JC may be a candidate pan-inflammasome inhibitor.

Maltol, a Natural Flavor Enhancer, Inhibits NLRP3 and Non-Canonical Inflammasome Activation

Maltol (3-hydroxy-2-methyl-4-pyrone) is used widely as a food and cosmetic supplement, and it has antioxidant and anti-inflammatory activities. Inflammasome causes the maturation and secretion of interleukin (IL)-1β and -18 through the activation of caspase-1 (Casp1), which contributes to various inflammatory diseases. This study examined the effects of maltol on the inflammasome activation in macrophages and mice. Lipopolysaccharide (LPS)-primed macrophages were treated with a trigger of NLRP3, NLRC4, AIM2, or non-canonical (NC) inflammasomes in the presence of maltol. The secretion of IL-1β and IL-18 and the cleavage of Casp1 were analyzed as indices of inflammasome activation. Mice were injected with LPS and an NLRP3 trigger with or without maltol, and the peritoneal IL-1β secretions were observed. The effects of maltol on reactive oxygen species (ROS) production and Casp1 activity were analyzed to determine the mechanism. Maltol inhibited the activation of NLRP3 and NC inflammasomes, but it did not alter the other inflammasomes. Maltol also attenuated IL-1β secretion resulting from the inflammasome activation in mice. The anti-inflammatory mechanism of maltol was revealed by the inhibition of ROS production and Casp1 activity. Maltol is suggested to be promising as a anti-inflammasome molecule.

The protective effects of S14G-humanin (HNG) against mono-sodium urate (MSU) crystals- induced gouty arthritis

Gout is a common and complex form of arthritis that has brought great inconveniences to the normal lives of patients. It is reported that oxidative stress and nod-like receptor family protein 3 (NLRP3) inflammasome-mediated inflammatory reactions are involved in the pathogenesis of gout arthritis. S14G-humanin (S14G-HNG) is a modified peptide of HNG with higher inhibitory activity on the accumulation and deposition of Aβ. Recently, S14G-HNG has been reported to exert great anti-inflammatory effects. The present study proposed to explore the possible therapeutic property of S14G-HNG against gout arthritis. An animal model was established by stimulation with mono-sodium urate (MSU) crystals, followed by treatment with colchicine and S14G-HNG, respectively. The elevated Gait score promoted synovitis score and activated myeloperoxidase (MPO) observed in MSU crystals-treated mice were significantly reversed by colchicine and S14G-HNG. Bone marrow-derived macrophages (BMDMs) were isolated from mice and stimulated with MSU crystals, followed by being treated with 25 and 50 μM S14G-HNG. The increased mitochondrial reactive oxygen species (ROS) and Malondialdehyde (MDA) levels, upregulated NADPH oxidase-4 (NOX-4), activated NLRP3 inflammasome, and elevated production of inflammatory factors in MSU crystals-treated BMDMs were dramatically reversed by S14G-HNG, accompanied by the upregulation of sirtuin type-1 (SIRT1). Lastly, the protective effects of S14G-HNG against MSU crystals-induced NLRP3 inflammasome activation were significantly abolished by the knockdown of SIRT1. In conclusion, our data reveal that S14G-HNG could possess potential benefits against MSU crystals-induced gout arthritis, with colchicine displaying a better effect.

A novel mechanism of Korean red ginseng-mediated anti-inflammatory action via targeting caspase-11 non-canonical inflammasome in macrophages

Background

Korean Red Ginseng (KRG) was reported to play an anti-inflammatory role, however, previous studies largely focused on the effects of KRG on priming step, the inflammation-preparing step, and the anti-inflammatory effect of KRG on triggering, the inflammation-activating step has been poorly understood. This study demonstrated anti-inflammatory role of KRG in caspase-11 non-canonical inflammasome activation in macrophages during triggering of inflammatory responses.

Methods

Caspase-11 non-canonical inflammasome-activated J774A.1 macrophages were established by priming with Pam3CSK4 and triggering with lipopolysaccharide (LPS). Cell viability and pyroptosis were examined by MTT and lactate dehydrogenase (LDH) assays. Nitric oxide (NO)-inhibitory effect of KRG was assessed using a NO production assay. Expression and proteolytic cleavage of proteins were examined by Western blotting analysis. In vivo anti-inflammatory action of KRG was evaluated with the LPS-injected sepsis model in mice.

Results

KRG reduced LPS-stimulated NO production in J774A.1 cells and suppressed pyroptosis and IL-1β secretion in caspase-11 non-canonical inflammasome-activated J774A.1 cells. Mechanistic studies demonstrated that KRG suppressed the direct interaction between LPS and caspase-11 and inhibited proteolytic processing of both caspase-11 and gasdermin D in caspase-11 non-canonical inflammasome-activated J774A.1 cells. Furthermore, KRG significantly ameliorated LPS-mediated lethal septic shock in mice.

Conclusion

The results demonstrate a novel mechanism of KRG-mediated anti-inflammatory action that operates through targeting the caspase-11 non-canonical inflammasome at triggering step of macrophage-mediated inflammatory response.

Parabens disrupt non-canonical inflammasome activation

Parabens are synthetic chemicals widely used as preservatives in cosmetics, pharmaceuticals, and foods. Although parabens, i.e., ethyl- and methyl-parabens, are considered relatively safe, study of possible health hazards has been undertaken due to the frequent exposure to parabens and their accumulation in the body. In this study, we elucidated the effect of parabens on inflammasome induction of inflammatory responses in innate immunity, such as interleukin (IL)-1β maturation and gasdermin D (GSDMD)-mediating pyroptosis. Parabens attenuated the inflammatory responses to intracellular lipopolysaccharide (LPS) triggering of non-canonical (NC) inflammasome activation, but did not alter canonical inflammasome (i.e., NLRP3, NLRC4 and AIM2) responses. The NC inflammasome is assembled by the interaction of murine caspase (Casp)-11 (Casp4/5 in human) with cytosolic LPS, inducing endotoxin sepsis. Parabens selectively inhibited NC inflammasome activation in both human and murine macrophages and diminished the peritoneal IL-1β production in LPS-injected mice. Parabens blocked the cleavage of GSDMD, Casp1, and Casp4, but did not change the expression of Casp11 or the activity of Casp1. Taken together, the results indicate that parabens could disrupt Gram-negative pathogen infection through the inhibition of NC inflammasome activation.

Lower Temperatures Exacerbate NLRP3 Inflammasome Activation by Promoting Monosodium Urate Crystallization, Causing Gout

Gout is a recurrent and chronic form of arthritis caused by the deposition of monosodium urate (MSU) crystals in the joints. Macrophages intake MSU crystals, the trigger for NLRP3 inflammasome activation, which leads to the release of interleukin (IL)-1β and results in the flaring of gout. The effects of temperature, an environmental factor for MSU crystallization, on IL-1β secretion have not been well studied. This study examined the effects of temperature on inflammasome activation. Specific triggers activated canonical inflammasomes (NLRP3, NLRC4, and AIM2) in murine macrophages at various temperatures (25, 33, 37, 39, and 42 °C). The maturation of IL-1β and caspase-1 was measured as an indicator for inflammasome activation. As expected, the optimal temperature of inflammasome activation was 37 °C. The MSU crystal-mediated activation of inflammasome increased at temperatures lower than 37 °C and decreased at higher temperatures. MSU crystals at lower temperatures enhanced IL-1β secretion via the NLRP3 inflammasome pathway. A lower temperature promoted the formation of MSU crystals without changing phagocytosis. Overall, lower temperatures form more MSU crystals and enhance NLRP3 inflammasome activation. In light of these findings, it is possible that hyperthermia therapy may reduce gout flaring.

NLRP3 Triggers Attenuate Lipocalin-2 Expression Independent with Inflammasome Activation

Lipocalin-2 (LCN2), a small secretory glycoprotein, is upregulated by toll-like receptor (TLR) signaling in various cells and tissues. LCN2 inhibits bacterial growth by iron sequestration and regulates the innate immune system. Inflammasome activates the inflammatory caspases leading to pyroptosis and cytokine maturation. This study examined the effects of inflammasome activation on LCN2 secretion in response to TLR signaling. The triggers of NLRP3 inflammasome activation attenuated LCN2 secretion while it induced interleukin-1β in mouse macrophages. In mice, NLRP3 inflammasome activation inhibited TLR-mediated LCN2 secretion. The inhibition of NLRP3 triggers on LCN2 secretion was caused by the inhibited transcription and translation of LCN2. At the same time, no changes in the other cytokines and IκBζ, a well-known transcriptional factor of Lcn2 transcription, were observed. Overall, NLRP3 triggers are a regulator of LCN2 expression suggesting a new linkage of inflammasome activation and LCN2 secretion in the innate immunity.