Methylsulfonylmethane inhibits NLRP3 inflammasome activation

Methylsulfonylmethane ameliorates metabolic-associated fatty liver disease by restoring autophagy flux via AMPK/mTOR/ULK1 signaling pathway

Introduction: Metabolism-associated fatty liver disease (MAFLD) is a global health concern because of its association with obesity, insulin resistance, and other metabolic abnormalities. Methylsulfonylmethane (MSM), an organic sulfur compound found in various plants and animals, exerts antioxidant and anti-inflammatory effects. Here, we aimed to assess the anti-obesity activity and autophagy-related mechanisms of Methylsulfonylmethane. Method: Human hepatoma (HepG2) cells treated with palmitic acid (PA) were used to examine the effects of MSM on autophagic clearance. To evaluate the anti-obesity effect of MSM, male C57/BL6 mice were fed a high-fat diet (HFD; 60% calories) and administered an oral dose of MSM (200 or 400 mg/kg/day). Moreover, we investigated the AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin complex 1 (mTORC1)/UNC-51-like autophagy-activating kinase 1 (ULK1) signaling pathway to further determine the underlying action mechanism of MSM. Results: Methylsulfonylmethane treatment significantly mitigated PA-induced protein aggregation in human hepatoma HepG2 cells. Additionally, Methylsulfonylmethane treatment reversed the PA-induced impairment of autophagic flux. Methylsulfonylmethane also enhanced the insulin sensitivity and significantly suppressed the HFD-induced obesity and hepatic steatosis in mice. Western blotting revealed that Methylsulfonylmethane improved ubiquitinated protein clearance in HFD-induced fatty liver. Remarkably, Methylsulfonylmethane promoted the activation of AMPK and ULK1 and inhibited mTOR activity. Conclusion: Our study suggests that MSM ameliorates hepatic steatosis by enhancing the autophagic flux via an AMPK/mTOR/ULK1-dependent signaling pathway. These findings highlight the therapeutic potential of MSM for obesity-related MAFLD treatment.

Methylsulfonylmethane Improves Knee Quality of Life in Participants with Mild Knee Pain: A Randomized, Double-Blind, Placebo-Controlled Trial

Methylsulfonylmethane (MSM) is a food ingredient present in small amounts in many foods, and its anti-inflammatory effects have been reported. We conducted a randomized, double-blind, placebo-controlled trial of oral consumption of MSM on mild pain of the knee joint in healthy Japanese participants. A total of 88 participants were enrolled in this study and randomly assigned to MSM consumption (n = 44) and placebo control (n = 44) groups. Both groups of participants took 10 tablets, each containing 200 mg MSM or lactose, per day for 12 weeks. The primary outcome of this study was measured values of the total score of the Japanese Knee Osteoarthritis Measure (JKOM) at 12 weeks after the test sample consumption. Safety evaluation was performed through physical examination, urine analysis, peripheral blood test, and medical interview. The total scores at 12 weeks in the MSM and placebo groups as the primary outcome were significantly different (p = 0.046). The health condition of JKOM also improved after MSM consumption (p = 0.032). The questionnaire results also suggested improvement in the knee and systemic health. This study indicated that MSM oral consumption improved both knee and systemic health conditions in healthy participants who experienced mild pain in the knee joint.

EVALUATION OF THE EFFECT OF TOPICALLY APPLIED METHYLSULFONYLMETHANE AND THEIR COMBINATION WITH MINOXIDIL SOLUTION FOR IMPROVEMENT OF HAIR GROWTH IN MALE MICE

OBJECTIVE

The aim: The purpose of this research was to find out the effect of Methylsulfonylmethane in minimizing hair loss.

PATIENTS AND METHODS

Materials and methods: Twenty adult Wister Albino mice weighing 25-35g and aged 6-7 weeks were employed. Male mice's coat hairs on the dorsal skin were carefully clipped and then colored. Mice were randomly assigned into four groups, each with five animals: (1) Control group: Treated with D.W. (2), Minoxidil (5%) treated group (3), Methylsulfonylmethane (10%) treated group (4), Methylsulfonylmethane plus Minoxidil treated group.

RESULTS

Results: We found that the tissue level of 8-isoprastanein the groups receiving medication are considerably lower than in the control (D.W.). We also discovered that the serum tissue vascular endothelial growth factor levels in the groups receiving medication are considerably greater than those in the control (D.W.) groups. On the other hand, we discovered that hair growth, hair follicle expansion and hair follicle number are much higher in the groups receiving medication than in the control groups.

CONCLUSION

Conclusions: We concluded that MSM, through its antioxidant and anti-inflammatory properties, dramatically reduces hair loss in male mice.

Expression of Human Immunodeficiency Virus Transactivator of Transcription (HIV-Tat1-86) Protein Alters Nociceptive Processing that is Sensitive to Anti-Oxidant and Anti-Inflammatory Interventions

Despite the success of combined antiretroviral therapy (cART) in reducing viral load, a substantial portion of Human Immunodeficiency Virus (HIV)+ patients report chronic pain. The exact mechanism underlying this co-morbidity even with undetectable viral load remains unknown, but the transactivator of transcription (HIV-Tat) protein is of particular interest. Functional HIV-Tat protein is observed even in cerebrospinal fluid of patients who have an undetectable viral load. It is hypothesized that Tat protein exposure is sufficient to induce neuropathic pain-like manifestations via both activation of microglia and generation of oxidative stress. iTat mice conditionally expressed Tat_(1-86) protein in the central nervous system upon daily administration of doxycycline (100 mg/kg/d, i.p., up to 14 days). The effect of HIV-Tat protein exposure on the well-being of the animal was assessed using sucrose-evoked grooming and acute nesting behavior for pain-depressed behaviors, and the development of hyperalgesia assessed with warm-water tail-withdrawal and von Frey assays for thermal hyperalgesia and mechanical allodynia, respectively. Tissue harvested at select time points was used to assess ex vivo alterations in oxidative stress, astrocytosis and microgliosis, and blood-brain barrier integrity with assays utilizing fluorescence-based indicators. Tat protein induced mild thermal hyperalgesia but robust mechanical allodynia starting after 4 days of exposure, reaching a nadir after 7 days. Changes in nociceptive processing were associated with reduced sucrose-evoked grooming behavior without altering acute nesting behavior, and in spinal cord dysregulated free radical generation as measured by DCF fluorescence intensity, altered immunohistochemical expression of the gliotic markers, Iba-1 and GFAP, and increased permeability of the blood-brain barrier to the small molecule fluorescent tracer, sodium fluorescein, in a time-dependent manner. Pretreatment with the anti-inflammatory, indomethacin (1 mg/kg/d, i.p.), the antioxidant, methylsulfonylmethane (100 mg/kg/d i.p.), or the immunomodulatory agent, dimethylfumarate (100 mg/kg/d p.o.) thirty minutes prior to daily injections of doxycycline (100 mg/kg/d i.p.) over 7 days significantly attenuated the development of Tat-induced mechanical allodynia. Collectively, the data suggests that even acute exposure to HIV-1 Tat protein at pathologically relevant levels is sufficient to produce select neurophysiological and behavioral manifestations of chronic pain consistent with that reported by HIV-positive patients.

Korean Red Ginseng, a regulator of NLRP3 inflammasome, in the COVID-19 pandemic

Coronavirus disease 2019 (COVID-19) exhibits various symptoms, ranging from asymptomatic to severe pneumonia or death. The major features of patients in severe COVID-19 are the dysregulation of cytokine secretion, pneumonia, and acute lung injury. Consequently, it leads to acute respiratory distress syndrome, disseminated intravascular coagulation, multiple organ failure, and death. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative virus of COVID-19, influences nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 3 (NLRP3), the sensor of inflammasomes, directly or indirectly, culminating in the assembly of NLRP3 inflammasome and activation of inflammatory caspases, which induce the inflammatory disruption in severe COVID-19. Accordingly, the target therapeutics for inflammasome has attracted attention as a treatment for COVID-19. Korean Red Ginseng (KRG) inhibits several inflammatory responses, including the NLRP3 inflammasome signaling. This review discusses the role of KRG in the treatment and prevention of COVID-19 based on its anti-NLRP3 inflammasome efficacy.

Methylsulfonylmethane protects against lethal dose MRSA-induced sepsis through promoting M2 macrophage polarization

BACKGROUND

Multi-drug-resistant bacterial infections, which have become a global threat, lack effective treatments. The discoveries of non-antibiotics with different modes of antibacterial action, such as methylsulfonylmethane (MSM), are a promising new treatment for multi-drug-resistant pathogens.

METHODS

We constructed a mouse peritonitis infection model to evaluate the effects of MSM against methicillin-resistant Staphylococcus aureus (MRSA) infection. The time-kill kinetics of MSM against MRSA and the effect of MSM on the integrity of bacterial cell membrane were measured. Viability effects of MSM on THP1 cells were performed by CCK-8 cytotoxicity assay. Systematic inflammatory factor levels of mice were detected using ELISA. The immune response of peritoneal macrophages during MRSA-infection was evaluated using RNA sequencing. Gene Ontology function, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, and correlation analyses were applied to analysis RNA sequencing data. RT-qPCR, western blotting and flow cytometry were performed to analysis the gene and protein expression levels of macrophages.

RESULTS

In in vitro experiments, MSM did not show significant killing effects on the growth of MRSA directly and did not destroy bacterial membrane integrity. MSM also displayed no significant effects on the proliferative capacity of THP1 cells. However, MSM treatment protected mice against a lethal dose MRSA-infection and decreased systemic inflammation. MSM upregulated metabolic pathway in peritoneal macrophages, especial glycolysis, during MRSA infection. MSM increased the expression of M2 markers (such as Arg1), promoted phosphorylation of STAT3 (which regulates M2 polarization), and decreased the expression of M1 markers in peritoneal macrophages. Additionally, MSM treatment increased the expression of H3K18 lactylation specific target genes, including Arg1. GNE-140, the LDHA-specific inhibitor of glycolysis, blocked the MSM-induced Arg1 expression in this disease model.

CONCLUSIONS

MSM protects against MRSA infection through immunomodulation. MSM promotes the expression of Arg1 by lactate-H3K18la pathway to control macrophage to M2 polarization; it firstly provides therapeutic potential for drug-resistant infections and sepsis.

Methylsulfonylmethane protects against ethanol-induced brain injury in mice through the inhibition of oxidative stress, proinflammatory mediators and apoptotic cell death

Excessive ethanol consumption causes brain injury through oxidative stress, inflammation and apoptotic cell death. Methylsulfonylmethane (MSM) is a natural compound that has therapeutic effects on oxidative and inflammatory disorders. The aim of this study was to investigate the protective effect and underlying mechanisms of MSM on ethanol-induced brain injury in an experimental model. Male C57BL/6 mice were exposed to binge ethanol (5 g/kg/day, orally) and treated with MSM (200 and 400 mg/kg/day) concomitantly for 12 days. At the end of the experiment brain tissues were removed for histological and biochemical analysis. The results showed that MSM reduced ethanol-mediated oxidative stress by decreasing the levels of malondialdehyde (MDA) and carbonyl protein. The Nrf2/HO-1 pathway and the levels of cytoprotective antioxidants superoxide dismutase (SOD), catalase and glutathione (GSH) were increased by MSM in the brain tissue. MSM treatment reduced the ethanol-induced inflammatory factors including myeloperoxidase (MPO), iNOS/NO, cyclooxygenase (COX)-2, nuclear factor kappa B (NF-κB), NLRP3 inflammasome and proinflammatory cytokines including TNF-α, IL-1β, IL-6 and MCP-1. MSM also decreased the levels of pro-apoptotic caspase-3 and TUNEL positive cells while increased the level of anti-apoptotic Bcl-2 in the brain tissue. Our findings demonstrated that MSM protects against ethanol-induced brain injury by improving anti-oxidant defense mechanism and reducing ethanol-mediated inflammation and apoptosis. Therefore, MSM may be a potential protective approach for brain damage caused by high levels of alcohol.

Modulatory Properties of Food and Nutraceutical Components Targeting NLRP3 Inflammasome Activation

Inflammasomes are key intracellular multimeric proteins able to initiate the cellular inflammatory signaling pathway. NLRP3 inflammasome represents one of the main protein complexes involved in the development of inflammatory events, and its activity has been largely demonstrated to be connected with inflammatory or autoinflammatory disorders, including diabetes, gouty arthritis, liver fibrosis, Alzheimer’s disease, respiratory syndromes, atherosclerosis, and cancer initiation. In recent years, it has been demonstrated how dietary intake and nutritional status represent important environmental elements that can modulate metabolic inflammation, since food matrices are an important source of several bioactive compounds. In this review, an updated status of knowledge regarding food bioactive compounds as NLRP3 inflammasome modulators is discussed. Several chemical classes, namely polyphenols, organosulfurs, terpenes, fatty acids, proteins, amino acids, saponins, sterols, polysaccharides, carotenoids, vitamins, and probiotics, have been shown to possess NLRP3 inflammasome-modulating activity through in vitro and in vivo assays, mainly demonstrating an anti-NLRP3 inflammasome activity. Plant foods are particularly rich in important bioactive compounds, each of them can have different effects on the pathway of inflammatory response, confirming the importance of the nutritional pattern (food model) as a whole rather than any single nutrient or functional compound.

Nutraceutical Approach to Chronic Osteoarthritis: From Molecular Research to Clinical Evidence

Osteoarthritis (OA) is a degenerative inflammatory condition of the joint cartilage that currently affects approximately 58 million adults in the world. It is characterized by pain, stiffness, and a reduced range of motion with regard to the arthritic joints. These symptoms can cause in the long term a greater risk of overweight/obesity, diabetes mellitus, and falls and fractures. Although the current guidelines for the treatment of OA suggest, as the gold standard for this condition, pharmacological treatment characterized by non-steroidal anti-inflammatory drugs (NSAID), opioids, and cyclooxygenase (COX)-2-specific drugs, a great interest has been applied to nutraceutical supplements, which include a heterogeneous class of molecules with great potential to reduce inflammation, oxidative stress, pain, and joint stiffness and improve cartilage formation. The purpose of this review is to describe the potential application of nutraceuticals in OA, highlighting its molecular mechanisms of actions and data of efficacy and safety (when available).

Methylsulfonylmethane Increases the Alveolar Bone Density of Mandibles in Aging Female Mice

Methylsulfonylmethane (MSM) is a naturally occurring anti-inflammatory compound that effectively treats multiple degenerative diseases such as osteoarthritis and acute pancreatitis. Our previous studies have demonstrated the ability of MSM to differentiate stem cells from human exfoliated deciduous (SHED) teeth into osteoblast-like cells. This study examined the systemic effect of MSM in 36-week-old aging C57BL/6 female mice in vivo by injecting MSM for 13 weeks. Serum analyses showed an increase in expression levels of bone formation markers [osteocalcin (OCN) and procollagen type 1 intact N-terminal propeptide (P1NP)] and a reduction in bone resorption markers [tartrate-resistant acid phosphatase (TRAP) and C-terminal telopeptide of type I collag (CTX-I)] in MSM-injected animals. Micro-computed tomographic images demonstrated an increase in trabecular bone density in mandibles. The trabecular bone density tended to be higher in the femur, although the increase was not significantly different between the MSM- and phosphate-buffered saline (PBS)-injected mice. In mandibles, an increase in bone density with a corresponding decrease in the marrow cavity was observed in the MSM-injected mice. Furthermore, immunohistochemical analyses of the mandibles for the osteoblast-specific marker - OCN, and the mesenchymal stem cell-specific marker - CD105 showed a significant increase and decrease in OCN and CD105 positive cells, respectively. Areas of bone loss were observed in the inter-radicular region of mandibles in control mice. However, this loss was considerably decreased due to stimulation of bone formation in response to MSM injection. In conclusion, our study has demonstrated the ability of MSM to induce osteoblast formation and function in vivo, resulting in increased bone formation in the mandible. Hence, the application of MSM and stem cells of interest may be the right combination in alveolar bone regeneration under periodontal or other related diseases that demonstrate bone loss.

The Effect of Daily Methylsulfonylmethane (MSM) Consumption on High-Density Lipoprotein Cholesterol in Healthy Overweight and Obese Adults: A Randomized Controlled Trial

Interventions to decrease inflammation and improve metabolic function hold promise for the prevention of obesity-related diseases. Methylsulfonylmethane (MSM) is a naturally occurring compound that demonstrates antioxidant and anti-inflammatory effects. Improvements in measures of metabolic health have been observed in mouse models of obesity and diabetes following MSM treatment. However, the effects of MSM on obesity-related diseases in humans have not been investigated. Therefore, the purpose of this investigation was to determine whether MSM supplementation improves cardiometabolic health, and markers of inflammation and oxidative status. A randomized, double-blind, placebo-controlled design was utilized with a total of 22 overweight or obese adults completing the study. Participants received either a placebo (white rice flour) or 3 g MSM daily for 16 weeks. Measurements occurred at baseline and after 4, 8, and 16 weeks. Outcome measures included fasting glucose, insulin, blood lipids, blood pressure, body composition, metabolic rate, and markers of inflammation and oxidative status. The primary finding of this work shows that high-density lipoprotein cholesterol was elevated at 8 and 16 weeks of daily MSM consumption compared to baseline, (p = 0.008, p = 0.013). Our findings indicate that MSM supplementation may improve the cholesterol profile by resulting in higher levels of high-density lipoprotein cholesterol.

Methylsulfonylmethane enhances MSC chondrogenic commitment and promotes pre-osteoblasts formation

BACKGROUND

Methylsulfonylmethane (MSM) is a nutraceutical compound which has been indicated to counteract osteoarthritis, a cartilage degenerative disorder. In addition, MSM has also been shown to increase osteoblast differentiation. So far, few studies have investigated MSM role in the differentiation of mesenchymal stem cells (MSCs), and no study has been performed to evaluate its overall effects on both osteogenic and chondrogenic differentiation. These two mutually regulated processes share the same progenitor cells.

METHODS

Therefore, with the aim to evaluate the effects of MSM on chondrogenesis and osteogenesis, we analyzed the expression of SOX9, RUNX2, and SP7 transcription factors in vitro (mesenchymal stem cells and chondrocytes cell lines) and in vivo (zebrafish model). Real-time PCR as well Western blotting, immunofluorescence, and specific in vitro and in vivo staining have been performed. Student's paired t test was used to compare the variation between the groups.

RESULTS

Our data demonstrated that MSM modulates the expression of differentiation-related genes both in vitro and in vivo. The increased SOX9 expression suggests that MSM promotes chondrogenesis in treated samples. In addition, RUNX2 expression was not particularly affected by MSM while SP7 expression increased in all MSM samples/model analyzed. As SP7 is required for the final commitment of progenitors to preosteoblasts, our data suggest a role of MSM in promoting preosteoblast formation. In addition, we observed a reduced expression of the osteoclast-surface receptor RANK in larvae and in scales as well as a reduced pERK/ERK ratio in fin and scale of MSM treated zebrafish.

CONCLUSIONS

In conclusion, our study provides new insights into MSM mode of action and suggests that MSM is a useful tool to counteract skeletal degenerative diseases by targeting MSC commitment and differentiation.

Molecular and cellular mechanisms of liver fibrosis and its regression

Chronic liver injury leads to liver inflammation and fibrosis, through which activated myofibroblasts in the liver secrete extracellular matrix proteins that generate the fibrous scar. The primary source of these myofibroblasts are the resident hepatic stellate cells. Clinical and experimental liver fibrosis regresses when the causative agent is removed, which is associated with the elimination of these activated myofibroblasts and resorption of the fibrous scar. Understanding the mechanisms of liver fibrosis regression could identify new therapeutic targets to treat liver fibrosis. This Review summarizes studies of the molecular mechanisms underlying the reversibility of liver fibrosis, including apoptosis and the inactivation of hepatic stellate cells, the crosstalk between the liver and the systems that orchestrate the recruitment of bone marrow-derived macrophages (and other inflammatory cells) driving fibrosis resolution, and the interactions between various cell types that lead to the intracellular signalling that induces fibrosis or its regression. We also discuss strategies to target hepatic myofibroblasts (for example, via apoptosis or inactivation) and the myeloid cells that degrade the matrix (for example, via their recruitment to fibrotic liver) to facilitate fibrosis resolution and liver regeneration.

Dietary Thiols: A Potential Supporting Strategy against Oxidative Stress in Heart Failure and Muscular Damage during Sports Activity

Moderate exercise combined with proper nutrition are considered protective factors against cardiovascular disease and musculoskeletal disorders. However, physical activity is known not only to have positive effects. In fact, the achievement of a good performance requires a very high oxygen consumption, which leads to the formation of oxygen free radicals, responsible for premature cell aging and diseases such as heart failure and muscle injury. In this scenario, a primary role is played by antioxidants, in particular by natural antioxidants that can be taken through the diet. Natural antioxidants are molecules capable of counteracting oxygen free radicals without causing cellular cytotoxicity. In recent years, therefore, research has conducted numerous studies on the identification of natural micronutrients, in order to prevent or mitigate oxidative stress induced by physical activity by helping to support conventional drug therapies against heart failure and muscle damage. The aim of this review is to have an overview of how controlled physical activity and a diet rich in antioxidants can represent a "natural cure" to prevent imbalances caused by free oxygen radicals in diseases such as heart failure and muscle damage. In particular, we will focus on sulfur-containing compounds that have the ability to protect the body from oxidative stress. We will mainly focus on six natural antioxidants: glutathione, taurine, lipoic acid, sulforaphane, garlic and methylsulfonylmethane.

Modulatory effect of methylsulfonylmethane against BPA/γ-radiation induced neurodegenerative alterations in rats: Influence of TREM-2/DAP-12/Syk pathway

AIMS

Methylsulfonylmethane (MSM), is an organosulfur compound, has many health benefits. Bisphenol-A (BPA) and γ-radiation (R) are two risky environmental contaminants that human beings are exposed to in everyday life. This work aims at unveiling the modulatory role of MSM in combating BPA and R co-exposure induced neurodegenerative disorder (Alzheimer's (AD)-mimic neurotoxicity).

MAIN METHODS

Female rats were randomly divided into five groups. One group was normal control and the other four groups were subjected to subacute BPA intoxication and/or exposed to fractionated weekly doses of R for 4 weeks and either untreated or treated with MSM concomitantly.

KEY FINDINGS

BPA and R co-exposure induced typical hallmarks of neurodegenerative disorders as revealed by tremendously elevated oxidative stress, extensive neuroinflammation (tumor necrosis factor -α and interleukin-1β), elevated AD markers (amyloid-beta (Aβ₄₂), acetylcholinesterase (AchE) activity and tau-phosphorylation) in cortex and hippocampus as well as up-regulation of microglial pro-inflammatory triggering receptor expressed on myeloid cell-2(TREM-2)/DNAX-activating protein of 12 kDa (DAP-12)/spleen-tyrosine kinase (Syk) pathway and its downstream targets (PLC-γ/DAG/p38-MAPK) in hippocampus. Also, neurodegenerative lesions were revealed in histopathological examination of cortex and hippocampus coupled with marked Aβ deposition in hippocampus. Whereas, MSM treatment improved histopathological insults and ameliorated level of oxidative stress, neuroinflammation and AD markers as well as modulated TREM-2/DAP-12/Syk pathway.

SIGNIFICANCE

Our data suggest that MSM afforded neuroprotection against BPA and R; supporting its potential application in the associated neurodegenerative disorders.

Transungual Delivery, Anti-Inflammatory Activity, and In Vivo Assessment of a Cyclodextrin Polypseudorotaxanes Nail Lacquer

A new cyclodextrin polypseudorotaxanes nail lacquer (Regenail^®) containing biotin, methyl sulphonyl methane (MSM), and dimethylsilanediol salicylate was developed and evaluated in vitro and in vivo. The product was developed to improve nail status and diminish signs of pathological nail alterations. A reference product (Betalfatrus^®) was used for comparative purposes. An in vitro permeation experiment in hooves showed high MSM and biotin absorption. The content of sulfur and silicon in hooves was also found to be higher compared with the reference product. MSM was tested in human keratinocytes, exhibiting a good cytotoxicity profile and anti-inflammatory activity by the reduction in IL-8 and TNF-α under LPS stimuli. A clinical study was performed to check product safety and efficacy against nail brittleness and alterations such as Beau's lines and onychorrhexis. A reduction in both alterations and in surface roughness without alteration of nail structure was observed, with a good level of patient acceptance and satisfaction.

Fructose-arginine, a non-saponin molecule of Korean Red Ginseng, attenuates AIM2 inflammasome activation

Background

Korean Red Ginseng extract (RGE) has been reported to act as an inflammasome modulator. Ginsenosides, saponin molecules of RGE, selectively inhibit activation of NLRP3 and AIM2 inflammasomes, while non-saponin molecules of RGE upregulate inflammasome components associated with the initiation of NLRP3 inflammasome activation. In this study, we investigated the effect of non-saponin components of RGE on AIM2 inflammasome activation.

Methods

The role of non-saponins of RGE on AIM2 inflammasomes was tested in mouse bone marrow-derived macrophages, a human monocyte-like cell line, and a mouse animal model. Cells or mice were transfected with dsDNA or inoculated with Listeria monocytogenes to activate AIM2 inflammasomes. Several indices of inflammasome activation were examined via immunoblot or ELISA analysis.

Results

The non-saponin fraction and saponin-eliminating fraction (SEF) of RGE selectively attenuated the activation of AIM2 inflammasomes, but not that of NLRP3 or NLRC4 inflammasomes. Fructose-arginine, an amino-sugar, was shown to be effective against AIM2 inflammasome activation.

Conclusion

Non-saponins of RGE, such as fructose-arginine, might be effective in regulating infectious and autoimmune diseases resulting from AIM2 inflammasome activation.

Methylsulfonylmethane Exhibits Bacteriostatic Inhibition of Vancomycin-Resistant Enterococcus faecium, In Vitro

The aim of this study was to evaluate the antibacterial properties of methylsulfonylmethane (MSM) on vancomycin-resistant Enterococcus faecium (VRE). Bacterial proliferation was measured spectrophotometrically during growth in brain heart infusion broth with 0%, 3%, 5%, 7%, 10%, 12%, and 16% MSM. To assess the mechanism of inhibition, VRE was grown overnight with 0-16% MSM and enumerated on unmedicated and medicated (3-16% MSM) brain heart infusion agar (BHIA). Viability studies were performed to evaluate the impact of 10-16% MSM on VRE over 7 days. Absorbance data indicated a dose-dependent inhibition from 0% to 7% MSM and no increase in optical density in 10-16% MSM. VRE enumerated on unmedicated BHIA from overnight cultures with 10-16% MSM partially recovered. No growth was observed when BHIA contained 10-16% MSM. There was little effect on VRE growth in 10% MSM over 7 days. VRE displayed a population rebound on day 6 when exposed to 12% MSM, and elimination by day 6 in 16% MSM. Regrowth after MSM removal may be indicative of a bacteriostatic mechanism of inhibition. Cell elimination in 16% MSM suggests inhibition of an essential metabolic function from which the bacterium could not recover.

Organosulfur Compounds: A Review of Their Anti-inflammatory Effects in Human Health

Phytonutrients are widely recognized for providing protective human health benefits. Among the phytonutrients, epidemiological and experimental studies show that dietary organosulfur compounds (OSC) play a significant role in preventing various human pathological progressions, including chronic inflammation, by decreasing inflammatory mediators such as nitric oxide (NO), prostaglandin (PG)E₂, interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and IL-17, which are all typical hallmarks of inflammation. Evidence supports OSC in reducing the expression of these markers, thereby attenuating chronic inflammatory processes. Nuclear factor-kappa B (NF-κB) is a key regulating factor during inflammation, and novel evidence shows that OSC downregulates this transcriptional factor, thus contributing to the anti-inflammatory response. In vitro and in vivo studies show that inflammation is mechanistically linked with acute and chronic pathological conditions including cancer, diabetes, obesity, neural dysfunction, etc. Furthermore, a considerable number of experiments have demonstrated that the anti-inflammatory properties of OSC occur in a dose-dependent manner. These experiments also highlight indirect mechanisms as well as potent co-functions for protective roles as antioxidants, and in providing chemoprotection and neuroprotection. In this brief review, we provided an overview of the anti-inflammatory effects of OSC and elucidated probable mechanisms that are associated with inflammation and chronic disorders.

Characterization of equine inflammasomes and their regulation

Inflammasome, a cytosolic multi-protein complex, assembly is a response to sensing intracellular pathogenic and endogenic danger signals followed by caspase-1 activation, which maturates precursor cytokines such as interleukin (IL)-1β. Most inflammasome research has been undertaken in humans and rodents, and inflammasomes in veterinary species have not been well-characterized. In this study, we observed the effects of well-known inflammasome activators on equine peripheral blood monocytes (PBMCs). The NLRP3 inflammasome triggers include ATP, nigericin, aluminum crystals, and monosodium urate crystals, and NLRP3 activation induces IL-1β secretion in a dose-dependent manner. Activators of NLRC4 and AIM2 inflammasomes include cytosolic flagellin and dsDNA, and their activation induces IL-1β secretion. The bacterial inflammasome triggers Salmonella Typhimurium and Listeria monocytogenes also induce IL-β releases. To elucidate the role of potassium efflux as an upstream signal of NLRP3 inflammasome activation, equine PBMCs were treated with blockers of potassium efflux in the presence of NLRP3 triggers. As a result, the IL-1β secretion stemming from equine NLRP3 inflammasome activation was not completely attenuated by the inhibition of potassium efflux. Taken together, the results indicate that equine PBMCs normally secrete IL-1β in response to well-known inflammasome activators, although equine NLRP3 inflammasome activation might not be dependent on potassium efflux.

Beauty from within: Oral administration of a sulfur-containing supplement methylsulfonylmethane improves signs of skin ageing

Abstract. Background: Methylsulfonylmethane (MSM) is an organosulfur compound with known benefits for joint health, sports nutrition, immune function, and anti‐aging formulations and is gaining popularity as a nutritional supplement for the support of hair, skin and nails. Methods: The study was conducted in two steps; in Part I (pilot study) a panel of 20 participants ingested either 3 g a day of MSM or placebo capsules for 16 weeks. Visual and subject self assessment of wrinkles and skin texture as the predominant sign of ageing was observed. In Part II (dose-response study), 63 participants ingested either 1 g or 3 g per day of MSM for 16 weeks. Expert clinical grading, instrumental measurements and consumer perception was used to evaluate skin conditions like lines and wrinkles. Additionally, instrumentational analysis was conducted using corneometer and cutometer for investigation of skin hydration, firmness and elasticity. Results: Part I of the study clearly indicates that oral ingestion of MSM (3 g/d) reduces signs of ageing like facial wrinkles ( p < 0.05) and skin roughness ( p < 0.05) as compared to placebo. Detailed analysis in Part II instrumentation assessments showed a significant ( p < 0.05) improvement from baseline in the severity of facial wrinkles, as well as improved skin firmness, elasticity and hydration with MSM. Some of these parameters exhibited a good dose-response indicating that the higher (3 g/d) of the supplement was more effective than the lower dose of 1 g/d, but generally the lower dose of 1 g/d appeared to be sufficiently effective in reducing the facial signs of ageing. Conclusion: This study indicated that MSM is effective in reducing visual signs of skin ageing even at a low dose of 1 g/d.

Purification of Methylsulfonylmethane from Mixtures Containing Salt by Conventional Electrodialysis

Methylsulfonylmethane (MSM) is one of the main sources of sulfur for living bodies, but it is hard to obtain as a pure compound. Conventional electrodialysis (CED) is a mature technology that can be used for the separation and purification of biochemical products. In this study, the purification of MSM from mixtures containing salt was performed by CED. The effects of operating conditions such as operation voltage drop, feed MSM concentration, and electrolyte salt concentration on the separation performances were investigated. The results showed that the current efficiency reached 74.0%, and the energy consumption could be 12.3 Wh·L⁻¹. As for the recovery rate and desalination rate, the highest recovery rate could be 97.4%, and the desalination rate was 98.5%. Based on process energy consumption calculation, the total cost of the whole process was estimated at only 2.34 $·t⁻¹. Thus, CED is highly efficient and cost-effective for the separation and purification of MSM.

IκBζ controls NLRP3 inflammasome activation via upregulation of the Nlrp3 gene

Inflammasome activation induces the maturation and secretion of interleukin (IL)-1β and -18, and is dependent on NF-κB signaling to induce the transcription of the inflammasome components, called the priming step. This study elucidated the role of IκBζ, an atypical IκBs (inhibitor of κB) and a coactivator of NF-κB target genes, on the activation of inflammasome. Bone marrow-derived macrophages (BMDMs) that originated from IκBζ-encoding Nfkbiz gene depletion mice presented a defect in NLRP3 inflammasome activation. In addition, the Nfkbiz^+/- and Nfkbiz^-/- mice significantly attenuated serum IL-1β secretion in response to a monosodium urate injection, a NLRP3 trigger, when compared with Nfkbiz^-+/+ mice. The lack of IκBζ in BMDMs produced a disability in the expression of Nlrp3 and pro-Il1β mRNAs during the priming step. In addition, ectopic IκBζ expression enhanced the Nlrp3 promoter activity, and Nlrp3 and pro-Il1β transcription. Overall, IκBζ controlled the activation of NLRP3 inflammasome by upregulating the Nlrp3 gene during the priming step.

Methylsulfonylmethane exhibits bacteriostatic inhibition of Escherichia coli, and Salmonella enterica Kinshasa, in vitro

AIMS

To evaluate antibacterial properties of methylsulfonylmethane (MSM) on Escherichia coli (MDRE21) and Salmonella enterica serovar Kinshasa (SK132).

METHODS AND RESULTS

Bacterial proliferation analysis was measured spectrophotometrically during log phase growth with 0, 3, 5, 7, 10, 12 and 16% MSM. To assess the mechanism of inhibition, cultures were grown overnight with 0-16% MSM and enumerated on unmedicated brain-heart infusion agar (BHIA) or BHIA with 0-16% MSM. The long-term viability studies were done to evaluate the impact of 10% MSM. Absorbance data indicated a dose-dependent inhibition from 0 to 16% MSM. There was no growth of MDRE21 or SK132 on BHIA in 10-16% MSM. Both strains enumerated on unmedicated BHIA from overnight cultures with 10-16% MSM were able to partially recover.

CONCLUSIONS

Recovery after MSM removal may be indicative of a bacteriostatic mechanism of inhibition. The long-term viability studies illustrated that neither MDRE21 nor SK132 could be rescued from 10% MSM after 5 or 6 days respectively.

SIGNIFICANCE AND IMPACT OF THE STUDY

Methylsulfonylmethane antibacterial activity may prove useful during pre or postharvest food safety as a disinfectant. The primary benefit being, its clinical safety to humans. Comparisons to other disinfectants would also need to be done to determine if MSM was superior to those already on the market and would be cost effective.

Raltegravir Attenuates Experimental Pulmonary Fibrosis In Vitro and In Vivo

Raltegravir, an inhibitor of human immunodeficiency virus-1 (HIV-1) integrase, has been used to treat HIV/acquired immunodeficiency syndrome; however, its therapeutic effects on pulmonary fibrosis have not been investigated. In this study, the in vitro effects of raltegravir (RAV) on transforming growth factor beta 1 (TGF-β1)-induced pulmonary fibrosis on L929 mouse fibroblasts were investigated. In addition, the effects of RAV on an in vivo pulmonary fibrosis model induced by intratracheal instillation of bleomycin were investigated. The proliferation of L929 cells was inhibited after RAV treatment. Meanwhile, the in vitro and in vivo protein expression of nucleotide-binding oligomerization domain-like receptor 3 (NLRP3), high-mobility group box 1 (HMGB1), toll-like receptor 4 (TLR4), prolyl hydroxylase domain protein 2, phosphorylated nuclear factor-κB (p-NF-κB), hypoxia-inducible factor-1α (HIF-1α), collagens I and III was reduced relative to TGF-β1 or the bleomycin group. Raltegravir ameliorated pulmonary fibrosis by reducing the pathology score, collagen deposition, and expression of α-smooth muscle actin, NLRP3, HMGB1, TLR4, inhibitor of kappa B, p-NF-κB, HIF-1α, collagen I, and collagen III. The results of this study demonstrate that RAV attenuated experimental attenuates pulmonary fibrosis by inhibiting NLRP3 activation.

Higher CSF Levels of NLRP3 Inflammasome Is Associated With Poor Prognosis of Anti-N-methyl-D-Aspartate Receptor Encephalitis

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is accepted as an autoimmune disorder of the central nervous system (CNS). NLR family pyrin domain containing 3 (NLRP3) inflammasome, a potent innate inflammatory mediator, can activate IL-1β and induce the migration of T helper cell into CNS. However, the possible role of NLRP3 inflammasome in the pathogenesis of anti-NMDAR encephalitis remains unclear. This study aims to determine the levels of NLRP3 and related cytokines (IL-1β, IL-6, and IL-17) in the cerebrospinal fluid (CSF) of anti-NMDAR encephalitis patients and to assess whether NLRP3 influences the clinical outcomes of this disease. Twenty-five patients with anti-NMDAR encephalitis, 12 viral meningoencephalitis patients and 26 controls with non-inflammatory neurological diseases were recruited. CSF NLRP3 inflammasome, IL-1β, IL-6, and IL-17 were measured by enzyme-linked immunosorbent assay. Thirteen out of 25 patients were re-examed for the concentrations of NLRP3 and cytokines 6 months later. Our results showed significant increases of CSF NLRP3 inflammasome, IL-1β, IL-6, and IL-17 in anti-NMDAR encephalitis patients. There were positive correlations between CSF NLRP3 inflammasome and cytokines in anti-NMDAR encephalitis patients. There was also a positive correlation between maximum modified Rankin Scale (mRS) scores and CSF NLRP3 inflammasome in anti-NMDAR encephalitis patients. During follow-up, the decrease of mRS was positively correlated with the decrease of CSF NLRP3 inflammasomes. These results suggested that the level of CSF NLRP3 inflammasome could represent the severity of anti-NMDAR encephalitis and the reduction of CSF NLRP3 inflammasome could act as an indicator for the prognosis of this disease.

Emerging Roles of Autophagy and Inflammasome in Ehrlichiosis

Human monocytic ehrlichiosis (HME) is a potentially life-threatening tick-borne rickettsial disease (TBRD) caused by the obligate intracellular Gram-negative bacteria, Ehrlichia. Fatal HME presents with acute ailments of sepsis and toxic shock-like symptoms that can evolve to multi-organ failure and death. Early clinical and laboratory diagnosis of HME are problematic due to non-specific flu-like symptoms and limitations in the current diagnostic testing. Several studies in murine models showed that cell-mediated immunity acts as a “double-edged sword” in fatal ehrlichiosis. Protective components are mainly formed by CD4 Th1 and NKT cells, in contrast to deleterious effects originated from neutrophils and TNF-α-producing CD8 T cells. Recent research has highlighted the central role of the inflammasome and autophagy as part of innate immune responses also leading to protective or pathogenic scenarios. Recognition of pathogen-associated molecular patterns (PAMPS) or damage-associated molecular patterns (DAMPS) triggers the assembly of the inflammasome complex that leads to multiple outcomes. Recognition of PAMPs or DAMPs by such complexes can result in activation of caspase-1 and -11, secretion of the pro-inflammatory cytokines IL-1β and IL-18 culminating into dysregulated inflammation, and inflammatory cell death known as pyroptosis. The precise functions of inflammasomes and autophagy remain unexplored in infections with obligate intracellular rickettsial pathogens, such as Ehrlichia. In this review, we discuss the intracellular innate immune surveillance in ehrlichiosis involving the regulation of inflammasome and autophagy, and how this response influences the innate and adaptive immune responses against Ehrlichia. Understanding such mechanisms would pave the way in research for novel diagnostic, preventative and therapeutic approaches against Ehrlichia and other rickettsial diseases.

P2X7 receptor antagonism ameliorates renal dysfunction in a rat model of sepsis

Sepsis is a major clinical problem associated with significant organ dysfunction and high mortality. The ATP‐sensitive P2X₇ receptor activates the NLRP3 inflammasome and is a key component of the innate immune system. We used a fluid‐resuscitated rat model of fecal peritonitis and acute kidney injury (AKI) to investigate the contribution of this purinergic receptor to renal dysfunction in sepsis. Six and 24 h time‐points were chosen to represent early and established sepsis, respectively. A selective P2X₇ receptor antagonist (A‐438079) dissolved in dimethyl sulfoxide (DMSO) was infused 2 h following induction of sepsis. Compared with sham‐operated animals, septic animals had significant increases in heart rate (−1(−4 to 8)% vs. 21(12–26)%; P = 0.003), fever (37.4(37.2–37.6)°C vs. 38.6(38.2–39.0)°C; P = 0.0009), and falls in serum albumin (29(27–30)g/L vs. 26(24–28); P = 0.0242). Serum IL‐1β (0(0–10)(pg/mL) vs. 1671(1445–33778)(pg/mL); P < 0.001) and renal IL‐1β (86(50–102)pg/mg protein vs. 200 (147–248)pg/mg protein; P = 0.0031) were significantly elevated in septic compared with sham‐operated animals at 6 h. Serum creatinine was elevated in septic animals compared with sham‐operated animals at 24 h (23(22–25) μmol/L vs. 28 (25–30)μmol/L; P = 0.0321). Renal IL‐1β levels were significantly lower in A‐438079‐treated animals compared with untreated animals at 6 h (70(55–128)pg/mg protein vs. 200(147–248)pg/mg protein; P = 0.021). At 24 h, compared with untreated animals, A‐438079‐treated animals had more rapid resolution of tachycardia (22(13–36)% vs. −1(−6 to 7)%; P = 0.019) and fever (39.0(38.6–39.1)°C vs. 38.2(37.6–38.7)°C; P < 0.024), higher serum albumin (23(21–25)g/L vs. (27(25–28)g/L); P = 0.006), lower arterial lactate (3.2(2.5–4.3)mmol/L vs. 1.4(0.9–1.8)mmol/L; P = 0.037), and lower serum creatinine concentrations (28(25–30)μmol/L vs. 22(17–27)μmol/L; P = 0.019). P2X₇A treatment ameliorates the systemic inflammatory response and renal dysfunction in this clinically relevant model of sepsis‐related AKI.

Methylsulfonylmethane and mobilee prevent negative effect of IL-1β in human chondrocyte cultures via NF-κB signaling pathway

Nutraceuticals are compounds that serve as nutrition with an easy accessibility and favourable safety profile. Recent studies showed their potential activity on osteoarthritis (OA) inflammation and cartilage metabolism. We investigated the effect of methylsulfonylmethane (MSM) and mobilee in human OA chondrocyte cultures exposed to interleukin (IL)-1β. OA cartilage was obtained from femoral heads of five patients undergoing total replacement surgery. Chondrocytes were incubated with mobilee (200 and 500 μM) and MSM (2000 and 6000 μM) in presence of IL-1β (10 ng/mL) and nuclear factor (NF)-κB inhibitor (BAY 11-7082, 1 μM), for 24 and 48 h. Viability and apoptosis were performed by MMT and flow cytometry. The metalloproteinase (MMP)-1,-3,-13 and type II collagen (Col2a1) were analyzed by qRT-PCR and ELISA, and NF-κB activation by immunofluorescence. IL-1β stimulus determined a significant regulation of survival, apoptotic ratio, as well as of gene expression and serum levels of MMP-1,-3,-13 and Col2a1 in OA chondrocytes compared to baseline. Mobilee and MSM incubation significantly reversed the effect of IL-1β. IL-1β significantly induced NF-κB p50 nuclear translocation, which was significantly counteracted by the pre-treatment of OA chodrocytes with the tested compounds. BAY11-7082 significantly modulated MMPs and Col2a1 expression respectively to basal state. Co-treatment of IL-1β with mobilee, MSM and BAY11-7082 didn't cause changes of MMPs or Col2a1 beyond that caused by each single treatment. We demonstrated that MSM and mobilee have a beneficial effect on OA chondrocytes metabolism, probably due to the modulation of NF-κB pathway, providing a powerful rationale for the use of these substances in OA treatment.

Mercury and arsenic attenuate canonical and non-canonical NLRP3 inflammasome activation

Exposure to heavy metals can cause several diseases associated with the immune system. Although the effects of heavy metals on production of inflammatory cytokines have been previously studied, the role of heavy metals in inflammasome activation remains poorly studied. The inflammasome is an intracellular multi-protein complex that detects intracellular danger signals, resulting in inflammatory responses such as cytokine maturation and pyroptosis. In this study, we elucidated the effects of four heavy metals, including cadmium (Cd), mercury (Hg), arsenic (As), and lead (Pb), on the activation of NLRP3, NLRC4, and AIM2 inflammasomes. In our results, mercury and arsenic inhibited interleukin (IL)-1β and IL-18 secretion resulting from canonical and non-canonical NLRP3 inflammasome activation in macrophages and attenuated elevation of serum IL-1β in response to LPS treatment in mice. In the mechanical studies, mercury interrupted production of mitochondrial reactive oxygen species, release of mitochondrial DNA, and activity of recombinant caspase-1, whereas arsenic down-regulated expression of promyelocytic leukemia protein. Both mercury and arsenic inhibited Asc pyroptosome formation and gasdermin D cleavage. Thus, we suggest that exposure to mercury and/or arsenic could disrupt inflammasome-mediated inflammatory responses, which might cause unexpected side effects.

Gingerol suppresses sepsis-induced acute kidney injury by modulating methylsulfonylmethane and dimethylamine production

Acute kidney injury (AKI) and metabolic dysfunction are critical complications in sepsis syndrome; however, their pathophysiological mechanisms remain poorly understood. Therefore, we evaluated whether the pharmacological properties of 6-gingerol (6G) and 10-gingerol (10G) could modulate AKI and metabolic disruption in a rat model of sepsis (faecal peritonitis). Animals from the sham and AKI groups were intraperitoneally injected with 6G or 10G (25 mg/kg). Septic AKI decreased creatinine clearance and renal antioxidant activity, but enhanced oxidative stress and the renal mRNA levels of tumour necrosis factor-α, interleukin-1β, and transforming growth factor-β. Both phenol compounds repaired kidney function through antioxidant activity related to decreased oxidative/nitrosative stress and proinflammatory cytokines. Metabolomics analysis indicated different metabolic profiles for the sham surgery group, caecal ligation and puncture model alone group, and sepsis groups treated with gingerols. ¹H nuclear magnetic resonance analysis detected important increases in urinary creatine, allantoin, and dimethylglycine levels in septic rats. However, dimethylamine and methylsulfonylmethane metabolites were more frequently detected in septic animals treated with 6G or 10G, and were associated with increased survival of septic animals. Gingerols attenuated septic AKI by decreasing renal disturbances, oxidative stress, and inflammatory response through a mechanism possibly correlated with increased production of dimethylamine and methylsulfonylmethane.

Poly-gamma-glutamic acid from Bacillus subtilis upregulates pro-inflammatory cytokines while inhibiting NLRP3, NLRC4 and AIM2 inflammasome activation

Poly-gamma-glutamic acid (γ-PGA) is a natural, edible and non-toxic polymer synthesized by Bacillus subtilis and is suggested as a safe biomaterial for the use in hydrogels and vaccine adjuvants. However, the effect of γ-PGA on inflammasome activation has not yet been studied in macrophages. Inflammasomes, which are intracellular multi-protein complexes, promote acute and chronic inflammation via interleukin-1β or interleukin-18 maturation, and they are known targets for metabolic syndromes and cancer. In this study, we observed that γ-PGA attenuated NLRP3, NLRC4 and AIM2 inflammasome activation, whereas it upregulated pro-inflammatory cytokine expression in human and murine macrophages. Although γ-PGA had conflicting effects on cytokine production and maturation, it clearly alleviated the severity of lipopolysaccharide-induced endotoxin shock in an animal model. Thus, we suggest γ-PGA as a candidate to control inflammasome-mediated disorders.

Role of inflammasome regulation on immune modulators

Inflammatory responses are essential in eliminating harmful substrates from damaged tissue and inducing recovery. Several cytokines participate in and facilitate this response. Certain cytokines such as interleukin (IL)-1β and IL-18 are initially produced in precursor form in response to toll-like receptor (TLR) ligands and undergo maturation by inflammasomes, which are cytosolic multi-protein complexes containing nucleotide-binding oligomerization domain (NOD)-containing protein 2-like receptors (NLRs). Immune modulators targeting inflammasomes have been investigated to control inflammatory diseases such as metabolic syndrome. However, most immune modulators possessing anti-inflammasome properties attenuate production of other cytokines, which are essential for host defense. In this review, we analyzed the effect of anti-inflammasome agents on the production of cytokines which are not regulated by inflammasome and involving in initial immune responses. As a result, the inflammasome inhibitors are put into three categories: non-effector, stimulator, or inhibitor of cytokine production. Even the stimulator of cytokine production ameliorated symptoms resulting from inflammasome activation in mouse models. Thus, we suggest ideal immune modulators targeting inflammasomes in order to enhance cytokine production while inhibiting cytokine maturation.

Methylene blue inhibits NLRP3, NLRC4, AIM2, and non-canonical inflammasome activation

Methylene blue (MB), which has antioxidant, anti-inflammatory, neuroprotective, and mitochondria protective effects, has been widely used as a dye and medication. However, the effect of MB on inflammasome activation has not yet been studied. Inflammasomes are multi-protein complexes that induce maturation of interleukins (ILs)-1β and -18 as well as caspase-1-mediated cell death, known as pyroptosis. Dysregulation of inflammasomes causes several diseases such as type 2 diabetes, Alzheimer’s disease, and gout. In this study, we assess the effect of MB on inflammasome activation in macrophages. As the result, MB attenuated activation of canonical inflammasomes such as NLRP3, NLRC4, and AIM2 as well as non-canonical inflammasome activation. In addition, MB inhibited upstream signals such as inflammasome assembly, phagocytosis, and gene expression of inflammasome components via inhibition of NF-κB signaling. Furthermore, MB reduced the activity of caspase-1. The anti-inflammasome properties of MB were further confirmed in mice models. Thus, we suggest that MB is a broad-spectrum anti-inflammasome candidate molecule.

Lentinan from shiitake selectively attenuates AIM2 and non-canonical inflammasome activation while inducing pro-inflammatory cytokine production

Lentinan extracted from shiitake (Lentinula edodes) is a β-glucan that has been reported as an intravenous anti-tumor polysaccharide via enhancement of the host immune system. In this study, we determined the effect of lentinan on inflammasome activation, a multi-protein platform, in myeloid cells. Mouse bone marrow-derived macrophages were treated with lentinan with/without inflammasome triggers, and maturation of interleukin (IL)-1β, IL-18, or caspase-1 was measured as a readout of inflammasome activation. As a result, lentinan selectively inhibited absent in melanoma 2 (AIM2) inflammasome activation. In addition, lentinan up-regulated pro-inflammatory cytokines and induced expression of inflammasome-related genes through toll-like receptor 4 signaling. Furthermore, we assessed the effect of lentinan on mice treated with Listeria monocytogenes or lipopolysaccharide as an AIM2 or non-canonical inflammasome-mediated model. Lentinan attenuated IL-1β secretion resulting from Listeria-mediated AIM2 inflammasome activation and reduced endotoxin lethality via inhibition of non-canonical inflammasome activation. Thus, lentinan is suggested as an anti-AIM2 and anti-non-canonical inflammasome candidate despite its up-regulation of cytokine expression.

Methylsulfonylmethane: Applications and Safety of a Novel Dietary Supplement

Methylsulfonylmethane (MSM) has become a popular dietary supplement used for a variety of purposes, including its most common use as an anti-inflammatory agent. It has been well-investigated in animal models, as well as in human clinical trials and experiments. A variety of health-specific outcome measures are improved with MSM supplementation, including inflammation, joint/muscle pain, oxidative stress, and antioxidant capacity. Initial evidence is available regarding the dose of MSM needed to provide benefit, although additional work is underway to determine the precise dose and time course of treatment needed to provide optimal benefits. As a Generally Recognized As Safe (GRAS) approved substance, MSM is well-tolerated by most individuals at dosages of up to four grams daily, with few known and mild side effects. This review provides an overview of MSM, with details regarding its common uses and applications as a dietary supplement, as well as its safety for consumption.

Isorhamnetin and hyperoside derived from water dropwort inhibits inflammasome activation

BACKGROUND

Water dropwort (Oenanthe javanica), an umbelliferous plant, has been reported as hypolipidemic, antiplatelet, antitumor, or immune-stimulating agents and it has been suggested to cure cardiovascular disease and cancer.

PURPOSE

Present study aimed to evaluate the effect of the extracts of water dropwort (EWD) and its pharmacological molecules, hyperoside and isorhamnetin, on inflammatory response, especially inflammasome activation.

STUDY DESIGN/METHODS

The anti-inflammasome properties of EWD, isorhamnetin, and hyperoside were elucidated by human and mouse macrophages.

RESULTS

EWD attenuated secretion of interleukin (IL)-1β and formation of Asc pyroptosome resulting from NLRP3, NLRC4, and AIM2 inflammasome activation without interruption of cytokine transcription. Isorhamnetin selectively inhibited NLRP3 and AIM2 inflammasome activation and down-regulated expression of pro-inflammatory cytokines. Hyperoside selectively interrupted NLRC4 and AIM2 inflammasome activation but did not alter cytokine expression. In addition, EWD, isorhamnetin, and hyperoside inhibited caspase-1.

CONCLUSION

Isorhamnetin and hyperoside, a key molecule of water dropwort, have been suggested as candidates to attenuate inflammasome inhibition.

The Influence of Methylsulfonylmethane on Inflammation-Associated Cytokine Release before and following Strenuous Exercise

Background. Inflammation is associated with strenuous exercise and methylsulfonylmethane (MSM) has been shown to have anti-inflammatory properties. Methods. Physically active men were supplemented with either placebo or MSM (3 grams per day) for 28 days before performing 100 repetitions of eccentric knee extension exercise. Ex vivo and in vitro testing consisted of evaluating cytokine production in blood (whole blood and isolated peripheral blood mononuclear cells (PBMCs)) exposed to lipopolysaccharide (LPS), before and through 72 hours after exercise, while in vivo testing included the evaluation of cytokines before and through 72 hours after exercise. Results. LPS stimulation of whole blood after MSM supplementation resulted in decreased induction of IL-1β, with no effect on IL-6, TNF-α, or IL-8. After exercise, there was a reduced response to LPS in the placebo, but MSM resulted in robust release of IL-6 and TNF-α. A small decrease in resting levels of proinflammatory cytokines was noted with MSM, while an acute postexercise increase in IL-10 was observed with MSM. Conclusion. Strenuous exercise causes a robust inflammatory reaction that precludes the cells from efficiently responding to additional stimuli. MSM appears to dampen the release of inflammatory molecules in response to exercise, resulting in a less incendiary environment, allowing cells to still have the capacity to mount an appropriate response to an additional stimulus after exercise.

Methylsulfonylmethane (MSM), an organosulfur compound, is effective against obesity-induced metabolic disorders in mice

Methylsulfonylmethane (MSM), an organosulfur compound, has been used as a dietary supplement that can improve various metabolic diseases. However, the effect of MSM on obesity-linked metabolic disorders remains unclear. The goal of the current study is to determine whether MSM has beneficial effects on glucose and lipid homeostasis in obesity-associated pathophysiologic states. High-fat diet-induced obese (DIO) and genetically obese diabetic db/db mice treated with MSM (1%-5% v/v, by drinking water) were studied. Metabolic parameters involved in glucose and lipid metabolism were determined. Treatment of DIO mice with MSM leads to a significant decrease in blood glucose levels. DIO mice treated with MSM are hypersensitive to insulin, as evidenced by decreased serum insulin and an increase in the area above the curve during an ITT. Concurrently, MSM reduces hepatic triglyceride and cholesterol contents in DIO mice. These effects are accompanied by reductions in gene expression of key molecules involved in lipogenesis and inflammation. FACS analysis reveals that MSM markedly increases the frequency of B cells and decreases the frequency of myeloid cells in peripheral blood and in bone marrow. Moreover, overnutrition-induced changes of femur microarchitecture are restored by MSM. In db/db mice, a marked impairment in glucose and lipid metabolic profiles is notably ameliorated when MSM is supplemented. These data suggest that MSM has beneficial effects on multiple metabolic dysfunctions, including hyperglycemia, hyperinsulinemia, insulin resistance, and inflammation. Thus, MSM could be the therapeutic option for the treatment of obesity-related metabolic disorders such as type 2 diabetes and fatty liver diseases.

Methylsulfonylmethane Induces p53 Independent Apoptosis in HCT-116 Colon Cancer Cells

Methylsulfonylmethane (MSM) is an organic sulfur-containing compound which has been used as a dietary supplement for osteoarthritis. MSM has been shown to reduce oxidative stress and inflammation, as well as exhibit apoptotic or anti-apoptotic effects depending on the cell type or activating stimuli. However, there are still a lot of unknowns about the mechanisms of actions of MSM. In this study, MSM was tested on colon cancer cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay and flow cytometric analysis revealed that MSM inhibited cell viability and increased apoptotic markers in both HCT-116 p53 +/+ and HCT-116 p53 −/− colon cancer cells. Increased poly (ADP-ribose) polymerase (PARP) fragmentation and caspase-3 activity by MSM also supported these findings. MSM also modulated the expression of various apoptosis-related genes and proteins. Moreover, MSM was found to increase c-Jun N-terminal kinases (JNK) phosphorylation in both cell lines, dose-dependently. In conclusion, our results show for the first time that MSM induces apoptosis in HCT-116 colon cancer cells regardless of their p53 status. Since p53 is defective in >50% of tumors, the ability of MSM to induce apoptosis independently of p53 may offer an advantage in anti-tumor therapy. Moreover, the remarkable effect of MSM on Bim, an apoptotic protein, also suggests its potential use as a novel chemotherapeutic agent for Bim-targeted anti-cancer therapies.

Oxalate, inflammasome, and progression of kidney disease

PURPOSE OF REVIEW

Oxalate is an end product of metabolism excreted via the kidney. Excess urinary oxalate, whether from primary or enteric hyperoxaluria, can lead to oxalate deposition in the kidney. Oxalate crystals are associated with renal inflammation, fibrosis, and progressive renal failure. It has long been known that as the glomerular filtration rate becomes reduced in chronic kidney disease (CKD), there is striking elevation of plasma oxalate. Taken together, these findings raise the possibility that elevation of plasma oxalate in CKD may promote renal inflammation and more rapid progression of CKD independent of primary cause.

RECENT FINDINGS

The inflammasome has recently been identified to play a critical role in oxalate-induced renal inflammation. Oxalate crystals have been shown to activate the NOD-like receptor family, pyrin domain containing 3 inflammasome (also known as NALP3, NLRP3, or cryopyrin), resulting in release of IL-1β and macrophage infiltration. Deletion of inflammasome proteins in mice protects from oxalate-induced renal inflammation and progressive renal failure.

SUMMARY

The findings reviewed in this article expand our understanding of the relevance of elevated plasma oxalate levels leading to inflammasome activation. We propose that inhibiting oxalate-induced inflammasome activation, or lowering plasma oxalate, may prevent or mitigate progressive renal damage in CKD, and warrants clinical trials.