Dimethyl sulfoxide inhibits NLRP3 inflammasome activation

Coenzyme Q10 and Vitamin E Alleviate Heat Stress-Induced Mood Disturbances in Male Mice: Modulation of Inflammatory Pathways and the HPA Axis

Heat stress, as an environmental stressor, can lead to temperature dysregulation and neuroinflammation, causing depression and anxiety by disrupting brain physiology and functional connectivity. This study looked at how co-enzyme Q10 (Q10) and vitamin E (Vit E), alone and together, affected heat stress-caused anxiety and depression symptoms and inflammation in male mice. Five groups were utilized in the study: control, heat stress (NS), Q10, Vit E, and the combination group (Q10+Vit E). The mice were subjected for 15min/day to a temperature of 43°C for 14 consecutive days, followed by daily treatments for two weeks with either normal saline, Q10 (500mg/kg), Vit E (250mg/kg), or their combination. The forced swimming test (FST) and tail suspension test (TST) were employed to evaluate despair behavior, whereas the elevated plus maze (EPM) and open field test (OFT) were used to assess anxious behaviors. Subsequently, the animals were sacrificed, and serum corticosterone levels, protein expression of inflammasome-related proteins, and hsp70 gene expression were evaluated in the prefrontal cortex (PFC). The study revealed that treatment with Vit E and Q10, alone or together, provided anxiolytic and antidepressant effects in the heat-stress-subjected animals. Also, giving Vit E and Q10 alone or together greatly lowered serum corticosterone levels. In the PFC, they also lowered the levels of hsp70 mRNA and NF-κB, caspase 1, NLRP3, and IL-1β proteins. It is speculated that treatment with Q10 and Vit E can attenuate heat stress-associated anxious and depressive responses by inhibiting the inflammatory pathways and modulating the hypothalamus-pituitary-adrenal axis.

Dimethyl sulfoxide as a novel therapy in a murine model of acute lung injury

INTRODUCTION

The endothelial glycocalyx on the luminal surface of endothelial cells contributes to the permeability barrier of the pulmonary vasculature. Dimethyl sulfoxide (DMSO) has a disordering effect on plasma membranes, which prevents the formation of ordered membrane domains important in the shedding of the endothelial glycocalyx. We hypothesized that DMSO would protect against protein leak by preserving the endothelial glycocalyx in a murine model of acute respiratory distress syndrome (ARDS).

METHODS

C57BL/6 mice were given ARDS via intratracheally administered lipopolysaccharide (LPS). Dimethyl sulfoxide (220 mg/kg) was administered intravenously for 4 days. Animals were sacrificed postinjury day 4 after bronchoalveolar lavage (BAL). Bronchoalveolar lavage cell counts and protein content were quantified. Lung sections were stained with fluorescein isothiocyanate-labeled wheat germ agglutinin to quantify the endothelial glycocalyx. Human umbilical vein endothelial cells (HUVECs) were exposed to LPS. Endothelial glycocalyx was measured using fluorescein isothiocyanate-labeled wheat germ agglutinin, and co-immunoprecipitation was performed to measure interaction between sheddases and syndecan-1.

RESULTS

Dimethyl sulfoxide treatment resulted in greater endothelial glycocalyx staining intensity in the lung when compared with sham (9,641 vs. 36,659 arbitrary units, p < 0.001). Total BAL cell counts were less for animals receiving DMSO (6.93 × 10 6 vs. 2.49 × 10 6 cells, p = 0.04). The treated group had less BAL macrophages (189.2 vs. 76.9 cells, p = 0.02) and lymphocytes (527.7 vs. 200.0 cells, p = 0.02). Interleukin-6 levels were lower in DMSO treated. Animals that received DMSO had less protein leak in BAL (1.48 vs. 1.08 μg/μL, p = 0.02). Dimethyl sulfoxide prevented LPS-induced endothelial glycocalyx loss in HUVECs and reduced the interaction between matrix metalloproteinase 16 and syndecan-1.

CONCLUSION

Systemically administered DMSO protects the endothelial glycocalyx in the pulmonary vasculature, mitigating pulmonary capillary leak after acute lung injury. Dimethyl sulfoxide also results in decreased inflammatory response. Dimethyl sulfoxide reduced the interaction between matrix metalloproteinase 16 and syndecan-1 and prevented LPS-induced glycocalyx damage in HUVECs. Dimethyl sulfoxide may be a novel therapeutic for ARDS.

Circadian Influences on Myocardial Ischemia-Reperfusion Injury and Heart Failure

The impact of circadian rhythms on cardiovascular function and disease development is well established, with numerous studies in genetically modified animals emphasizing the circadian molecular clock's significance in the pathogenesis and pathophysiology of myocardial ischemia and heart failure progression. However, translational preclinical studies targeting the heart's circadian biology are just now emerging and are leading to the development of a novel field of medicine termed circadian medicine. In this review, we explore circadian molecular mechanisms and novel therapies, including (1) intense light, (2) small molecules modulating the circadian mechanism, and (3) chronotherapies such as cardiovascular drugs and meal timings. These promise significant clinical translation in circadian medicine for cardiovascular disease. (4) Additionally, we address the differential functioning of the circadian mechanism in males versus females, emphasizing the consideration of biological sex, gender, and aging in circadian therapies for cardiovascular disease.

Local Scaffold Diversity-Contributed Generator for Discovering Potential NLRP3 Inhibitors

Deep generative models have become crucial tools in de novo drug design. In current models for multiobjective optimization in molecular generation, the scaffold diversity is limited when multiple constraints are introduced. To enhance scaffold diversity, we herein propose a local scaffold diversity-contributed generator (LSDC), which can be utilized to generate diverse lead compounds capable of satisfying multiple constraints. Compared to the state-of-the-art methods, molecules generated by LSDC exhibit greater diversity when applied to the generation of inhibitors targeting the NOD-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3). We present 12 molecules, some of which feature previously unreported scaffolds, and demonstrate their reasonable docking binding modes. Consequently, the modification of selected scaffolds and subsequent bioactivity evaluation lead to the discovery of two potent NLRP3 inhibitors, A22 and A14, with IC50 values of 38.1 nM and 44.43 nM, respectively. And the oral bioavailability of compound A14 is very high (F is 83.09% in mice). This work contributes to the discovery of novel NLRP3 inhibitors and provides a reference for integrating AI-based generation with wet experiments.

Astragaloside IV Inhibits Rotenone-Induced α-syn Presentation and the CD4 T-Cell Immune Response

The increased α-synuclein (α-syn)-dependent activation of CD4 T cells leads to the progressive loss of dopaminergic (DA) neurons in the substantia nigra (SN) in Parkinson's disease (PD). Astragaloside IV (AS-IV) protects DA neurons against neuroinflammation. The effects of AS-IV on CD4 T-cell-mediated immune responses in PD remain unknown. Rotenone (ROT) injected unilaterally into the substantia nigra pars compacta (SNc) of rats induced PD. AS-IV (20 mg/kg) was intraperitoneally injected once a day for 14 days. The limb hanging test and rotarod test were performed to evaluate the alteration of behavior at 4 and 6 weeks. Total gastrointestinal transit tests were performed at 4 weeks. Western blotting was used to detect the expression of proinflammatory cytokine proteins. Immunofluorescence staining was conducted to test the expression and localization of major histocompatibility complex class II (MHCII), cleaved caspase-1 and α-syn in astrocytes. Flow cytometry analysis, immunohistochemistry and immunofluorescence staining were used to measure the expression of CD4 T-cell subsets in the SN. The application of AS-IV protected against the loss of DA neurons and behavioral deficits in ROT-induced PD rat models. AS-IV administration inhibited the aggregation of α-syn in DA neurons and the expression of proinflammatory cytokines such as TNF-α, IL-18, IL-6 and IL-1β. AS-IV decreased the activation of CD4 T cells and three CD4 T-cell subsets: Tfh, Treg and Th1. AS-IV interrupted the ROT-induced interaction between astrocytes and CD4 T cells and the colocalization of MHCII and α-syn in astrocytes. AS-IV inhibited the expression of α-syn in astrocytes and the colocalization of α-syn and cleaved caspase-1 in astrocytes. AS-IV prevents the loss of DA neurons in PD by inhibiting the activation of α-syn-specific CD4 T cells, which is regulated by MHCII-mediated antigen presentation in astrocytes.

Expression analysis of Carassius auratus-leukocyte-immune-type receptors (CaLITRs) during goldfish kidney macrophage development and in activated kidney leukocyte cultures

Carassius auratus leukocyte immune-type receptors (CaLITRs) were recently discovered immunoregulatory receptors in goldfish that have diverse immunoglobulin-like (Ig-like) ectodomains and intracellular signaling motifs. Genomic analysis shows that CaLITR-types are also located as distinct gene clusters across multiple goldfish chromosomes. For example, CaLITR1 (unplaced) is a functionally ambiguous receptor having two Ig-like domains, a transmembrane domain (TM), and a short cytoplasmic tail (CYT) devoid of any recognizable signaling motifs. CaLITR2 (Chr47) is a putative inhibitory receptor containing four Ig-like domains, a TM, and a long CYT with an immunoreceptor tyrosine-based inhibition motif (ITIM) and immunoreceptor tyrosine-based switch motif (ITSM). A putative activating receptor-type, CaLITR3 (Chr3), has four Ig-like domains, a TM, and a short CYT containing a positively charged histidine residue and CaLITR4 (ChrLG28B) is a receptor with putative multifunctional signaling potential as well as five Ig-like domains, a TM, and a long tyrosine-motif containing CYT region. The variable genomic locations of the CaLITRs suggest that they are likely under the influence of different cis- and/or trans-regulatory elements. To better understand the transcriptional activities of select CaLITRs from variable genomic regions, we used an RT-qPCR-based approach to examine the expression of CaLITR1, CaLITR2, CaLITR3, and CaLITR4 during goldfish primary kidney macrophage (PKM) development and in mixed leukocyte reaction cultures (MLRs) of the goldfish. Our results showed that the select CaLITRs are differentially expressed during PKM development and in goldfish MLRs exposed to T-cell mitogens/immunosuppressive drugs, supporting that the transcription of these CaLITRs is likely regulated by distinct cis- and/or trans-regulatory elements.

Inflammasomes: Cause or consequence of obesity-associated comorbidities in humans

Inflammasomes are multiprotein intracellular complexes composed of innate immune system receptors and sensors; they activate the inflammatory cascade in response to infectious microbes and/or molecules derived from host proteins. Because of cytokine secretion, inflammasomes can induce amplified systemic responses, its dysregulation can exacerbate symptoms in infectious diseases, and it has been related to the development of autoimmune diseases, inflammatory disorders, and even cancer. Obesity is associated with a chronic low-grade inflammation, in which circulating proinflammatory cytokines are elevated. Some publications describe changes in inflammation markers as a consequence of obesity, but others suggest that chronic inflammation might cause obesity (e.g., C-reactive protein): these assumptions reflect the difficulty of identifying the appropriate role of inflammation as cause or consequence of obesity and its related complications. Obesity is recognized as a clinical risk factor for developing cardiovascular diseases including atherosclerosis, metabolic syndrome, insulin resistance, and diabetes mellitus. Changes in the expression of inflammasomes are described in some of these obesity-related complications, and moreover, its modulation might exert a beneficial effect in some cases. Despite some contradictory results, most publications suggest a promising clinical effect based on in vitro and in vivo experiments. In this review, we summarized recent publications about inflammasome dysregulation in humans and its relationship with obesity-related comorbidities.

Inflammasome Signaling in the Aging Brain and Age-Related Neurodegenerative Diseases

Inflammasomes are intracellular protein complexes, members of the innate immune system, and their activation and regulation play an essential role in maintaining homeostatic conditions against exogenous and endogenous stimuli. Inflammasomes occur as cytosolic proteins and assemble into a complex during the recognition of pathogen-associated or danger-associated molecular patterns by pattern-recognition receptors in host cells. The formation of the inflammasome complex elicits signaling molecules of proinflammatory cytokines such as interleukin-1β and interleukin 18 via activation of caspase-1 in the canonical inflammasome pathway whereas caspase-11 in the case of a mouse and caspase-4 and caspase-5 in the case of humans in the non-canonical inflammasome pathway, resulting in pyroptotic or inflammatory cell death which ultimately leads to neuroinflammation and neurodegenerative diseases. Inflammasome activation, particularly in microglial cells and macrophages, has been linked to aging as well as age-related neurodegenerative diseases. The accumulation of abnormal/ misfolded proteins acts as a ligand for inflammasome activation in neurodegenerative diseases. Although recent studies have revealed the inflammasomes' functionality in both in vitro and in vivo models, many inflammasome signaling cascade activations during biological aging, neuroinflammation, and neurodegeneration are still ambiguous. In this review, we comprehensively unveil the cellular and molecular mechanisms of inflammasome activation during neuronal aging and age-related neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, prion disease, and amyotrophic lateral sclerosis.

NLRP3 ablation enhances tolerance in heat stroke pathology by inhibiting IL-1β-mediated neuroinflammation

Background

Patients with prior illness are more vulnerable to heat stroke-induced injury, but the underlying mechanism is unknown. Recent studies suggested that NLRP3 inflammasome played an important role in the pathophysiology of heat stroke.

Methods

In this study, we used a classic animal heat stroke model. Prior infection was mimicked by using lipopolysaccharide (LPS) or lipoteichoic acid (LTA) injection before heat stroke (LPS/LTA 1 mg/kg). Mice survival analysis curve and core temperature (T_C) elevation curve were produced. NLRP3 inflammasome activation was measured by using real-time PCR and Western blot. Mice hypothalamus was dissected and neuroinflammation level was measured. To further demonstrate the role of NLRP3 inflammasome, Nlrp3 knockout mice were used. In addition, IL-1β neutralizing antibody was injected to test potential therapeutic effect on heat stroke.

Results

Prior infection simulated by LPS/LTA injection resulted in latent inflammation status presented by high levels of cytokines in peripheral serum. However, LPS/LTA failed to cause any change in animal survival rate or body temperature. In the absence of LPS/LTA, heat treatment induced heat stroke and animal death without significant systemic or neuroinflammation. Despite a decreased level of IL-1β in hypothalamus, Nlrp3 knockout mice demonstrated no survival advantage under mere heat exposure. In animals with prior infection, their heat tolerance was severely impaired and NLRP3 inflammasome induced neuroinflammation was detected. The use of Nlrp3 knockout mice enhanced heat tolerance and alleviated heat stroke-induced death by reducing mice hypothalamus IL-1β production with prior infection condition. Furthermore, IL-1β neutralizing antibody injection significantly extended endotoxemic mice survival under heat stroke.

Conclusions

Based on the above results, NLRP3/IL-1β induced neuroinflammation might be an important mechanistic factor in heat stroke pathology, especially with prior infection. IL-1β may serve as a biomarker for heat stroke severity and potential therapeutic method.

Pristimerin protects against inflammation and metabolic disorder in mice through inhibition of NLRP3 inflammasome activation

Excessive activation of NLRP3 inflammasome is associated with the pathogenesis of inflammatory diseases. Pristimerin (Pri) is a quinonoid triterpene derived from traditional Chinese medical herb Celastraceae and Hippocrateaceae. Pri has shown antifungal, antibacterial, antioxidant, and anticancer activities. In this study we investigated whether NLRP3 inflammasome was associated with the anti-inflammatory activity of Pri. We showed that Pri (0.1-0.4 μM) dose-dependently blocked caspase-1 activation and IL-1β maturation in LPS-primed mouse bone-marrow-derived macrophages (BMDMs). Pri specifically inhibited NLRP3 inflammasome activation, had no visible effects on NLRC4 and AIM2 inflammasome activation. Furthermore, we demonstrated that Pri blocked the assembly of the NLRP3 inflammasome via disturbing the interaction between NEK7 and NLRP3; the α, β-unsaturated carbonyl moiety of Pri was essential for NLRP3 inflammasome inactivation. In LPS-induced systemic inflammation mouse model and MSU-induced mouse peritonitis model, preinjection of Pri (500 μg/kg, ip) produced remarkable therapeutic effects via inhibition of NLRP3 inflammasome in vivo. In HFD-induced diabetic mouse model, administration of Pri (100 μg· kg-1 ·d-1, ip, for 6 weeks) reversed HFD-induced metabolic disorders via suppression of NLRP3 inflammasome activation. Taken together, our results demonstrate that Pri acts as a NLRP3 inhibitor, suggesting that Pri might be useful for the treatment of NLRP3-associated diseases.

Korean Red Ginseng attenuates ultraviolet-mediated inflammasome activation in keratinocytes

Background

Keratinocytes form a physical barrier and act as an innate immune cell in skin. Keratinocytes secrete pro-inflammatory cytokines, such as interleukin (IL)-1β, resulting from inflammasome activation when exposed to ultraviolet (UV) irradiation. Korean Red Ginseng extracts (RGE) have been well-studied as modulators of inflammasome activation in immune cells, such as macrophages. In the study, we elucidated the role of RGE on the UV-mediated inflammasome activation in keratinocytes compared with that in macrophages.

Methods

Human skin keratinocyte cells (HaCaT), human epidermal keratinocytes (HEK), human monocyte-like cells (THP-1), and mouse macrophages were treated with RGE or a saponin fraction (SF) or non-saponin fraction (NS) of RGE before and after UV irradiation. The secretion levels of IL-1β, as an indicator of inflammasome activation, were analyzed.

Results

The treatment of RGE or SF in macrophages after UV irradiation inhibited IL-1β secretion, but similar treatment in HaCaT cells did not. However, the treatment of RGE or SF in HaCaT cells in the presence of poly I:C, a toll-like receptor (TLR) 3 ligand, before UV exposure elicited the inhibition of the IL-1β secretion. The inhibition was caused by the disruption by RGE or SF of the TLR mediating up-regulation of the pro-IL-1β and NLRP3 genes during the priming step.

Conclusion

RGE and its saponins inhibit IL-1β secretion in response to UV exposure in both keratinocytes and macrophages. In particular, RGE treatment interrupted only the priming step in keratinocytes, although it did attenuate both the priming and activation steps in macrophages.

The Role of the Inflammasome in Neurodegenerative Diseases

Neurodegenerative diseases are chronic, progressive disorders that occur in the central nervous system (CNS). They are characterized by the loss of neuronal structure and function and are associated with inflammation. Inflammation of the CNS is called neuroinflammation, which has been implicated in most neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). Much evidence indicates that these different conditions share a common inflammatory mechanism: the activation of the inflammasome complex in peripheral monocytes and in microglia, with the consequent production of high quantities of the pro-inflammatory cytokines IL-1β and IL-18. Inflammasomes are a group of multimeric signaling complexes that include a sensor Nod-like receptor (NLR) molecule, the adaptor protein ASC, and caspase-1. The NLRP3 inflammasome is currently the best-characterized inflammasome. Multiple signals, which are potentially provided in combination and include endogenous danger signals and pathogens, trigger the formation of an active inflammasome, which, in turn, will stimulate the cleavage and the release of bioactive cytokines including IL-1β and IL-18. In this review, we will summarize results implicating the inflammasome as a pivotal player in the pathogenesis of neurodegenerative diseases and discuss how compounds that hamper the activation of the NLRP3 inflammasome could offer novel therapeutic avenues for these diseases.

Respiratory RNA Viruses: How to Be Prepared for an Encounter with New Pandemic Virus Strains

The characteristics of the biology of influenza viruses and coronavirus that determine the implementation of the infectious process are presented. With provision for pathogenesis of infection possible effects of serine proteinase inhibitors, heparin, and inhibitors of heparan sulfate receptors in the prevention of cell contamination by viruses are examined. It has been determined that chelators of metals of variable valency and antioxidants should be used for the reduction of replicative activity of viruses and anti-inflammatory therapy. The possibility of a pH-dependent impairment of glycosylation of cellular and viral proteins was traced for chloroquine and its derivatives. The use of low-toxicity drugs as part of adjunct therapy increases the effectiveness of synthetic antiviral drugs and interferons and ensures the safety of baseline therapy.

Therapeutic role of inflammasome inhibitors in neurodegenerative disorders

Neuroinflammation, characterized by the activation of glial cells, is a hallmark in several neurological and neurodegenerative disorders. Inadequate inflammation cannot eliminate the infection of pathogens, while excessive or hyper-reactive inflammation can cause chronic or systemic inflammatory diseases affecting the central nervous system (CNS). In response to a brain injury or pathogen invasion, the pathogen recognition receptors (PRRs) expressed on glial cells are activated via binding to cellular damage-associated molecular patterns (DAMPs) or pathogen-associated molecular patterns (PAMPs). This subsequently leads to the activation of NOD (nucleotide-binding oligomerization domain)-like receptor proteins (NLRs). In neurodegenerative diseases such as HIV-1-associated neurocognitive disorders (HAND), Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), chronic inflammation is a critical contributing factor for disease manifestation including pathogenesis. Emerging evidence points to the involvement of "inflammasomes", especially the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing (NLRP) complex in the development of these diseases. The activated NLRP3 results in the proteolytic activation of caspase-1 that facilitates the cleavage of pro-IL-1β and the secretion of IL-1β and IL-18 proinflammatory cytokines. Accordingly, these and other seminal findings have led to the development of NLRP-targeting small-molecule therapeutics as possible treatment options for neurodegenerative disorders. In this review, we will discuss the new advances and evidence-based literature concerning the role of inflammasomes in neurodegenerative diseases, its role in the neurological repercussions of CNS chronic infection, and the examples of preclinical or clinically tested NLRP inhibitors as potential strategies for the treatment of chronic neurological diseases.

A Rational Insight into the Effect of Dimethyl Sulfoxide on TNF-α Activity

Direct inhibition of tumor necrosis factor-alpha (TNF-α) action is considered a promising way to prevent or treat TNF-α-associated diseases. The trimeric form of TNF-α binds to its receptor (TNFR) and activates the downstream signaling pathway. The interaction of TNF-α with molecular-grade dimethyl sulfoxide (DMSO) in an equal volumetric ratio renders TNF-α inert, in this state, TNF-α fails to activate TNFR. Here, we aimed to examine the inhibition of TNF-α function by various concentrations of DMSO. Its higher concentration led to stronger attenuation of TNF-α-induced cytokine secretion by fibroblasts, and of their death. We found that this inhibition was mediated by a perturbation in the formation of the functional TNF-α trimer. Molecular dynamics simulations revealed a transient interaction between DMSO molecules and the central hydrophobic cavity of the TNF-α homodimer, indicating that a brief interaction of DMSO with the TNF-α homodimer may disrupt the formation of the functional homotrimer. We also found that the sensitizing effect of actinomycin D on TNF-α-induced cell death depends upon the timing of these treatments and on the cell type. This study will help to select an appropriate concentration of DMSO as a working solvent for the screening of water-insoluble TNF-α inhibitors.

Understanding the role of Inflammasome in Angina Pectoris

Angina pectoris, associated with coronary artery disease, a cardiovascular disease where, pain is caused by adverse oxygen supply in myocardium, resulting in contractility and discomfort in chest. Inflammasomes, triggered by stimuli due to infection and cellular stress have identified to play a vital role in the progression of cardiovascular disorders and thus, causing various symptoms like angina pectoris. Nlrp3 inflammasome, a key contributor in the pathogenesis of angina pectoris, requires activation and primary signaling for the commencement of inflammation. Nlrp3 inflammasome elicit out an inflammatory response by emission of pro inflammatory cytokines by ROS (reactive oxygen species) production, mobilization of K+ efflux and Ca2+ and by activation of lysosome destabilization that eventually causes pyroptosis, a programmed cell death process. Thus, inflammasome are considered to be one of the factors involved in the progression of coronary artery diseases and have an intricate role in development of angina pectoris.

The past, present and future of RNA respiratory viruses: influenza and coronaviruses

Influenza virus and coronaviruses continue to cause pandemics across the globe. We now have a greater understanding of their functions. Unfortunately, the number of drugs in our armory to defend us against them is inadequate. This may require us to think about what mechanisms to address. Here, we review the biological properties of these viruses, their genetic evolution and antiviral therapies that can be used or have been attempted. We will describe several classes of drugs such as serine protease inhibitors, heparin, heparan sulfate receptor inhibitors, chelating agents, immunomodulators and many others. We also briefly describe some of the drug repurposing efforts that have taken place in an effort to rapidly identify molecules to treat patients with COVID-19. While we put a heavy emphasis on the past and present efforts, we also provide some thoughts about what we need to do to prepare for respiratory viral threats in the future.

Selective inhibition of NLRP3 inflammasome by designed peptide originating from ASC

NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome is a multiprotein complex which forms within cells in response to various microbial and self-derived triggers. Mutations in the gene encoding NLRP3 cause rare cryopyrin-associated periodic syndromes (CAPS) and growing evidence links NLRP3 inflammasome to common diseases such as Alzheimer´s disease. In order to modulate different stages of NLRP3 inflammasome assembly nine peptides whose sequences correspond to segments of inflammasome components NLRP3 and apoptosis-associated speck-like protein containing a CARD (ASC) were selected. Five peptides inhibited IL-1β release, caspase-1 activation and ASC oligomerization in response to soluble and particulate NLRP3 triggers. Modulatory peptides also attenuated IL-1β maturation induced by constitutive CAPS-associated NLRP3 mutants. Peptide corresponding to H2-H3 segment of ASC pyrin domain selectively inhibited NLRP3 inflammasome by binding to NLRP3 pyrin domain in the micromolar range. The peptide had no effect on AIM2 and NLRC4 inflammasomes as well as NF-κB pathway. The peptide effectively dampened neutrophil infiltration in the silica-induced peritonitis and when equipped with Antennapedia or Angiopep-2 motifs crossed the blood-brain barrier in a mouse model. Our study demonstrates that peptides represent an important tool for targeting multiprotein inflammatory complexes and can serve as the basis for the development of novel anti-inflammatory strategies for neurodegeneration.

Lamivudine Inhibits Alu RNA-induced Retinal Pigment Epithelium Degeneration via Anti-inflammatory and Anti-senescence Activities

Purpose

Accumulation of the long noncoding Alu element RNA activates the NLRP3 inflammasome and leads to retinal pigment epithelium (RPE) cell death, a key event in the pathogenesis of geographic atrophy during late-stage age-related macular degeneration. Lamivudine (3TC) is a nucleoside analog reverse transcriptase inhibitor known to inhibit the NLRP3 inflammasome. Currently, the intracellular response of the senescence marker p16^Ink4a to the long noncoding RNA is being actively studied. The present study aimed to assess the efficacy of 3TC against Alu RNA-induced RPE inflammation and senescence by evaluating changes in expression of the proinflammatory cytokines IL-18 and IL-1β and of p16^INK4a in RPE cells.

Methods

Cultured human RPE cells and in vivo mouse RPE cells were transfected with an in vitro-transcribed Alu RNA, and changes in IL-18, IL-1β, and p16^Ink4a expression measured in the presences of 3TC or 3,4-(M)CA as a negative control.

Results

Treatment with 3TC markedly reduced Alu RNA-induced expression of IL-18 and IL-1β in human and mouse RPE cells compared with the negative control. Further, Alu RNA-induced p16^INK4a expression was suppressed by 3TC in human RPE cells.

Conclusions

Our data suggest that Alu RNA accumulation contributes to RPE cell senescence in age-related macular degeneration and that this pathogenic process can be suppressed by 3TC.

Translational Relevance

Further verifying this study leads to potential targets for age-related macular degeneration therapy.

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.

NLRP3 Inflammasome and Its Central Role in the Cardiovascular Diseases

Materials

The NLRP3 inflammasome controls the activation of the proteolytic enzyme caspase-1. Caspase-1 in turn regulates the maturation of the proinflammasome cytokines IL-1β and IL-18, which leads to an inflammatory response. We made a mini-review on the association of regulatory mechanisms of NLRP3 inflammasome with the development of cardiovascular diseases systematically based on the recent research studies. Discussion. The inflammasome plays an indispensable role in the development of atherosclerosis, coronary heart diseases (CHD), and heart ischemia-reperfusion (I/R) injury, and NLRP3 inflammasome may become a new target for the prevention and treatment of cardiovascular diseases. Effective regulation of NLRP3 may help prevent or even treat cardiovascular diseases.

Conclusion

This mini-review focuses on the association of regulatory mechanisms of NLRP3 inflammasome with the development of cardiovascular diseases, which may supply some important clues for future therapies and novel drug targets for cardiovascular diseases.

Immunomodulatory effects and potential clinical applications of dimethyl sulfoxide

Dimethyl sulfoxide (DMSO) was discovered during the 19th century by the German chemical industry. DMSO comprises a highly polar group and two non-polar domains, which render it soluble in both aqueous solutions and organic solutions. Furthermore, DMSO can penetrate the cell membrane of both the mammalian cells and the non-mammalian cells and prevent freeze-thaw injuries to the cells. Thus, it is frequently used for the cryopreservation of cells and tissues for laboratory and clinical applications. In contrast to this traditional application, DMSO has recently been shown to possess immunomodulatory effects, such as immune enhancement, and anti-inflammatory effects in the innate immunity. In addition, DMSO also affects the adaptive immunity by regulating the expression of transcription factors in immune cells. This review briefly summarizes and highlights the roles and immunomodulatory effects of DMSO on the immune system and reveals the future clinical therapeutic potential of DMSO treatment in cancer, in autoimmune diseases and in chronic inflammatory diseases.

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.

Therapeutic effects of an azaphenothiazine derivative in mouse experimental colitis

Phenothiazines represent a class of compounds of potential therapeutic utility. In this report we evaluated therapeutic value of an azaphenothiazine derivative, 6-acetylaminobutyl-9-chloroquino[3,2-b]benzo[1,4]thiazine (QBT), given intragastrically, in the model of dextran sodium sulfate-induced colitis in C57BL/6 mice using 5-aminosalicylic acid (5-ASA) as a reference drug. Colitis symptoms such as body weight loss, diarrhea and hematochezia (blood in stool) were observed and registered and disease activity index (DAI) was calculated. In addition, weight and cell numbers in the lymphatic organs and histological parameters of the colon wall were analyzed. The effects of QBT on viability of colon epithelial cell lines were also determined. We showed that weight and cell number of draining mesenteric lymph nodes were lower in mice treated with QBT in comparison to their control counterparts. The number of thymocytes, drastically reduced in control mice, was elevated in mice treated with the compounds with a significant effect of 5-ASA. In addition, an abnormal composition of blood cell types was partially corrected in these groups. Histological analysis of the colon revealed that the pathological changes were partially normalized by QBT and even to a higher degree by 5-ASA. In conclusion we demonstrated a therapeutic efficacy of the compound in amelioration of local and systemic pathological changes associated with chemically-induced colitis in mice. A possible mechanism of action of the compound is discussed.

Targeting NLRP3 Inflammasome Activation in Severe Asthma

Severe asthma (SA) is a chronic lung disease characterized by recurring symptoms of reversible airflow obstruction, airway hyper-responsiveness (AHR), and inflammation that is resistant to currently employed treatments. The nucleotide-binding oligomerization domain-like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome is an intracellular sensor that detects microbial motifs and endogenous danger signals and represents a key component of innate immune responses in the airways. Assembly of the NLRP3 inflammasome leads to caspase 1-dependent release of the pro-inflammatory cytokines IL-1β and IL-18 as well as pyroptosis. Accumulating evidence proposes that NLRP3 activation is critically involved in asthma pathogenesis. In fact, although NLRP3 facilitates the clearance of pathogens in the airways, persistent NLRP3 activation by inhaled irritants and/or innocuous environmental allergens can lead to overt pulmonary inflammation and exacerbation of asthma manifestations. Notably, administration of NLRP3 inhibitors in asthma models restrains AHR and pulmonary inflammation. Here, we provide an overview of the pathophysiology of SA, present molecular mechanisms underlying aberrant inflammatory responses in the airways, summarize recent studies pertinent to the biology and functions of NLRP3, and discuss the role of NLRP3 in the pathogenesis of asthma. Finally, we contemplate the potential of targeting NLRP3 as a novel therapeutic approach for the management of SA.

Tranilast directly targets NLRP3 to treat inflammasome-driven diseases

The dysregulation of NLRP3 inflammasome can cause uncontrolled inflammation and drive the development of a wide variety of human diseases, but the medications targeting NLRP3 inflammasome are not available in clinic. Here, we show that tranilast (TR), an old anti‐allergic clinical drug, is a direct NLRP3 inhibitor. TR inhibits NLRP3 inflammasome activation in macrophages, but has no effects on AIM2 or NLRC4 inflammasome activation. Mechanismly, TR directly binds to the NACHT domain of NLRP3 and suppresses the assembly of NLRP3 inflammasome by blocking NLRP3 oligomerization. In vivo experiments show that TR has remarkable preventive or therapeutic effects on the mouse models of NLRP3 inflammasome‐related human diseases, including gouty arthritis, cryopyrin‐associated autoinflammatory syndromes, and type 2 diabetes. Furthermore, TR is active ex vivo for synovial fluid mononuclear cells from patients with gout. Thus, our study identifies the old drug TR as a direct NLRP3 inhibitor and provides a potentially practical pharmacological approach for treating NLRP3‐driven 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.

Recent advances in the mechanisms of NLRP3 inflammasome activation and its inhibitors

The NLRP3 inflammasome is a multimeric protein complex that initiates an inflammatory form of cell death and triggers the release of proinflammatory cytokines IL-1β and IL-18. The NLRP3 inflammasome has been implicated in a wide range of diseases, including Alzheimer’s disease, Prion diseases, type 2 diabetes, and some infectious diseases. It has been found that a variety of stimuli including danger-associated molecular patterns (DAMPs, such as silica and uric acid crystals) and pathogen-associated molecular patterns (PAMPs) can activate NLRP3 inflammasome, but the specific regulatory mechanisms of NLRP3 inflammasome activation remain unclear. Understanding the mechanisms of NLRP3 activation will enable the development of its specific inhibitors to treat NLRP3-related diseases. In this review, we summarize current understanding of the regulatory mechanisms of NLRP3 inflammasome activation as well as inhibitors that specifically and directly target NLRP3.

STAT3 Phosphorylation Mediating DMSO's Function on Fetal Cardiomyocyte Proliferation with Developmental Changes

Endogenous cardiac regeneration has been focused for decades as a potential therapy for heart diseases with cell loss, and dimethyl sulfoxide (DMSO) has been proposed as a treatment for many diseases. In this study, we aimed to investigate the function of DMSO on fetal cardiomyocyte proliferation. By tracing BrdU⁺/α actinin⁺ cells or Ki67⁺/α actinin⁺ cells with immunohistochemical staining, we found that DMSO remarkably promoted fetal cardiomyocytes proliferation, and at the late developmental stage (LDS), such effects were more efficient than that at early developmental stage (EDS). Western blot data revealed a significant increase in STAT3 phosphorylation under DMSO treatments at LDS, while not at EDS. Consistently, STAT3 phosphorylation blocker STA21 could greatly reverse DMSO's function at LDS whereas hardly at EDS. Moreover, hearts at the EDS had less total STAT3 protein, but relatively much higher level of phosphorylated STAT3. This suggests that DMSO promote fetal cardiomyocytes proliferation, and STAT3 phosphorylation play a pivotal role in DMSO's function. With maturation, DMSO exerted a better ability to favor cardiomyocyte proliferation depending on STAT3 phosphorylation. Therefore, DMSO could serve as an effective, economic, and safe therapy for heart diseases with cell loss.

Evaluating the Impacts of Methylsulfonylmethane on Allergic Rhinitis After a Standard Allergen Challenge: Randomized Double-Blind Exploratory Study

Background

The sulfur-containing compound methylsulfonylmethane (MSM) has been used as a dietary supplement for a variety of reported health benefits. Clinical observations and case studies have indicated that MSM may help alleviate allergic rhinitis; however, this effect has not been evaluated under controlled conditions.

Objective

This study aimed to determine the effects of MSM consumption on allergic rhinitis symptoms after provocation with a standardized allergen.

Methods

We recruited healthy participants with a history of allergic nasal congestion to participate in a randomized, double-blind, adaptive-design study. Participants were administered a standardized allergen in clinic to determine the presence or absence of an allergic response. Participant responses were recorded using a recognized measure of nasal patency, peak nasal inspiratory flow (PNIF), and by a visual analog scale to score the severity of their allergy-related nasal symptoms. After we collected baseline nasal responses to allergen, followed by a 1-week washout period, participants returned to the clinic and were exposed to allergen after taking an acute high dose of 12 g of MSM. We then randomly assigned participants to a lower dose of MSM (1 g, 3 g, or 6 g), which they consumed once a day for 14 days. Participants returned to the clinic for repeat assessments while again taking their assigned daily dose of MSM.

Results

All MSM treatment courses significantly reduced visual analog scale average nasal symptoms in a longitudinal comparison across all participants, with low-dose treatments decreasing symptoms by 53.72% (P=.001), and an acute 12-g dose decreasing symptoms by 22.49% (P=.03). Although the acute dose of MSM did not yield significant changes in nasal patency, low “everyday” doses significantly relieved nasal obstruction as indicated by a 17.32% (P=.02) increase in PNIF across all participants. The most effective dose across all measurements was daily consumption of 3 g of MSM, which significantly decreased all nasal symptoms (nasal obstruction, rhinorrhea, watery or itchy eyes and nose, and sneezing) and further was found to significantly (P=.01) increase PNIF.

Conclusions

The MSM study product provided significant relief of allergic rhinitis symptoms and objective nasal obstruction measurements without the occurrence of adverse events. Oral consumption of the study product may reduce the symptoms and onset of allergic rhinitis without the side effects associated with standard-care medication.

Trial Registration

ClinicalTrials.gov NCT02342483; https://clinicaltrials.gov/ct2/show/NCT02342483 (Archived by WebCite at http://www.webcitation.org/73vLKNvAp)

Gliotransmitters and cytokines in the control of blood-brain barrier permeability

The contribution of astrocytes and microglia to the regulation of neuroplasticity or neurovascular unit (NVU) is based on the coordinated secretion of gliotransmitters and cytokines and the release and uptake of metabolites. Blood-brain barrier (BBB) integrity and angiogenesis are influenced by perivascular cells contacting with the abluminal side of brain microvessel endothelial cells (pericytes, astrocytes) or by immune cells existing (microglia) or invading the NVU (macrophages) under pathologic conditions. The release of gliotransmitters or cytokines by activated astroglial and microglial cells is provided by distinct mechanisms, affects intercellular communication, and results in the establishment of microenvironment controlling BBB permeability and neuroinflammation. Glial glutamate transporters and connexin and pannexin hemichannels working in the tight functional coupling with the purinergic system serve as promising molecular targets for manipulating the intercellular communications that control BBB permeability in brain pathologies associated with excessive angiogenesis, cerebrovascular remodeling, and BBB-mediated neuroinflammation. Substantial progress in deciphering the molecular mechanisms underlying the (patho)physiology of perivascular glia provides promising approaches to novel clinically relevant therapies for brain disorders. The present review summarizes the current understandings on the secretory machinery expressed in glial cells (glutamate transporters, connexin and pannexin hemichannels, exocytosis mechanisms, membrane-derived microvesicles, and inflammasomes) and the role of secreted gliotransmitters and cytokines in the regulation of NVU and BBB permeability in (patho)physiologic conditions.

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.

Inflammasomes, the eye and anti-inflammasome therapy

Inflammasomes, key molecular regulators that play an important role in inflammation, consist of a central protein, an adaptor protein ASC (apoptosis speck-like protein) and a caspase-1 protein. Upon activation, caspase-1 induces maturation of cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18). The release of these cytokines can result in inflammation. Inflammasomes are activated by a variety of factors and their activation involves complex signalling leading to resolution of infection, but can also contribute to the pathology of inflammatory, autoimmune, and infectious diseases. The role of NLRP1, NLRP3, NLRC4 and AIM2 inflammasomes in the pathogenesis of ocular diseases such as glaucoma, age related macular degeneration (AMD), diabetic retinopathy, dry eye and infections of the eye has been established over the past decade. In experimental studies and models, inhibition of inflammasomes generally helps to reduce the inflammation associated with these eye diseases, but as yet the role of these inflammasomes in many human eye diseases is unknown. Therefore, a need exists to study and understand various aspects of inflammasomes and their contribution to the pathology of human eye diseases. The goal of this review is to discuss the role of inflammasomes in the pathology of eye diseases, scope for anti-inflammasome therapy, and current research gaps in inflammasome-related eye disease.

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.

Effects of Methylsulfonylmethane (MSM) on exercise-induced oxidative stress, muscle damage, and pain following a half-marathon: a double-blind, randomized, placebo-controlled trial

Background

Oxidative stress and muscle damage occur during exhaustive bouts of exercise, and many runners report pain and soreness as major influences on changes or breaks in training regimens, creating a barrier to training persistence. Methylsulfonylmethane (MSM) is a sulfur-based nutritional supplement that is purported to have pain and inflammation-reducing effects. To investigate the effects of MSM in attenuating damage associated with physical exertion, this randomized, double-blind, placebo-controlled study evaluated the effects of MSM supplementation on exercise-induced pain, oxidative stress and muscle damage.

Methods

Twenty-two healthy females (n = 17) and males (n = 5) (age 33.7 ± 6.9 yrs.) were recruited from the 2014 Portland Half-Marathon registrant pool. Participants were randomized to take either MSM (OptiMSM®) (n = 11), or a placebo (n = 11) at 3 g/day for 21 days prior to the race and for two days after (23 total). Participants provided blood samples for measurement of markers of oxidative stress, and completed VAS surveys for pain approximately one month prior to the race (T₀), and at 15 min (T₁), 90 min (T₂), 1 Day (T₃), and 2 days (T₄) after race finish. The primary outcome measure 8-hydroxy-2-deoxyguanine (8-OHdG) measured oxidative stress. Secondary outcomes included malondialdehyde (MDA) for oxidative stress, creatine kinase (CK) and lactate dehydrogenase (LDH) as measures of muscle damage, and muscle (MP) and joint pain (JP) recorded using a 100 mm Visual Analogue Scale (VAS). Data were analyzed using repeated and multivariate ANOVAs, and simple contrasts compared post-race time points to baseline, presented as mean (SD) or mean change (95% CI) where appropriate.

Results

Running a half-marathon induced significant increases in all outcome measures (p < 0.001). From baseline, 8-OHdG increased significantly at T₁ by 1.53 ng/mL (0.86–2.20 ng/mL CI, p < 0.001) and T₂ by 1.19 ng/mL (0.37–2.01 ng/mL CI, p < 0.01), and fell below baseline levels at T₃ by −0.46 ng/mL (−1.18–0.26 CI, p > 0.05) and T₄ by −0.57 ng/mL (−1.27–0.13 CI, p > 0.05). MDA increased significantly at T₁ by 7.3 μM (3.9–10.7 CI, p < 0.001). Muscle damage markers CK and LDH saw significant increases from baseline at all time-points (p < 0.01). Muscle and joint pain increased significantly from baseline at T₁, T₂, and T₃ (p < 0.01) and returned to baseline levels at T₄. Time-by-treatment results did not reach statistical significance for any outcome measure, however, the MSM group saw clinically significant (Δ > 10 mm) reductions in both muscle and joint pain.

Conclusion

Participation in a half-marathon was associated with increased markers of oxidative stress, muscle damage, and pain. MSM supplementation was not associated with a decrease from pre-training levels of oxidative stress or muscle damage associated with an acute bout of exercise. MSM supplementation attenuated post-exercise muscle and joint pain at clinically, but not statistically significant levels.

Inhibition of NLRP3 Inflammasome Prevents LPS-Induced Inflammatory Hyperalgesia in Mice: Contribution of NF-κB, Caspase-1/11, ASC, NOX, and NOS Isoforms

The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3), an intracellular signaling molecule that senses many environmental- and pathogen/host-derived factors, has been implicated in the pathogenesis of several diseases associated with inflammation. It has been suggested that NLRP3 inflammasome inhibitors may have a therapeutic potential in the treatment of NLRP3-related inflammatory diseases. The aim of this study was to determine whether inhibition of NLRP3 inflammasome prevents inflammatory hyperalgesia induced by lipopolysaccharide (LPS) in mice as well as changes in expression/activity of nuclear factor κB (NF-κB), caspase-1/11, nicotinamide adenine dinucleotide phosphate oxidase (NOX), and endothelial/neuronal/inducible nitric oxide synthase (eNOS/nNOS/iNOS) that may regulate NLRP3/apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)/pro-caspase-1 inflammasome formation and activity by using a selective NLRP3 inflammasome inhibitor, MCC950. Male mice received saline (10 ml/kg; i.p.), LPS (10 mg/kg; i.p.), and/or MCC950 (3 mg/kg; i.p.). Reaction time to thermal stimuli within 1 min was evaluated after 6 h. The mice were killed and the brains, hearts, and lungs were collected for measurement of NF-κB, caspase-1, caspase-11, NLRP3, ASC, NOX subunits (gp91^phox; NOX2), and p47^phox; NOXO2), nitrotyrosine, eNOS, nNOS, iNOS, and β-actin protein expression, NOS activity, and interleukin (IL)-1β levels. LPS-induced hyperalgesia was associated with a decrease in eNOS, nNOS, and iNOS protein expression and activity as well as an increase in expression of NF-κB p65, caspase-1 p20, caspase-11 p20, NLRP3, ASC, gp91^phox, p47^phox, and nitrotyrosine proteins in addition to elevated IL-1β levels. The LPS-induced changes were prevented by MCC950. The results suggest that inhibition of NLRP3/ASC/pro-caspase-1 inflammasome formation and activity prevents inflammatory hyperalgesia induced by LPS in mice as well as changes in NF-κB, caspase-11, NOX2, NOXO2, and eNOS/nNOS/iNOS expression/activity.

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.

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.

NLRP3 inflammasome: A therapeutic option for kidney disease?

OBJECTIVE

To determine if considering inflammasome NLRP3 as a treatment option for kidney disease is possible.

METHODS

Literature review related to NLRP3 inflammasome structure, biological function and relationship with renal disease and others (hypertension, diabetes, gout, atherosclerosis, amyloidosis, Alzheimer's disease); the systematic review was made searching in the databases PubMed and SciELO for the following terms: "The NLRP3 inflammasome therapeutic for kidney disease", "NLRP3 nflammasome in kidney disease" in PubMed, and "Inflammasome" for Scielo.

RESULTS

146 documents were found, althoughonly 34 matched the working hypothesis concerning the NLRP3 inflammasome as a central component of various diseases in humans, with potential therapeutic use. The NLRP3 inflammasome is responsible for the maturation of inflammatory pro-interleukin IL-1 β and IL-18, which can be triggered by aggregated or crystalline materials (particles), and by various microorganisms and toxins derived from these; however, the way how activation mechanisms work is not completely clear.

CONCLUSIONS

Research on new therapies that focus on removing or inhibiting inflammasome components, both individually and together, is proposed.

Bone marrow stromal cells attenuate LPS-induced mouse acute liver injury via the prostaglandin E 2-dependent repression of the NLRP3 inflammasome in Kupffer cells

The nucleotide-binding and oligomerization domain-like receptor 3 (NLRP3) inflammasome participates in the pathogenesis of acute liver injury during sepsis. Bone marrow mesenchymal stem cells (BMSCs) attenuate sepsis through prostaglandin E 2 (PGE2) by increasing the interleukin-10 (IL-10) production of macrophages; moreover, NLRP3 inflammasome assembly is effectively regulated by IL-10 during infection. Whether BMSCs have an effect on the activation of the NLRP3 inflammasome and its underlying mechanism is unclear. Administering of BMSCs to mice or KCs after LPS stimulating have improved liver function and reduced activation of NLRP3 inflammasome in KCs. The beneficial effect of BMSCs was enhanced by over-expression of PGE2 and eliminated by silence of PGE2. Additionally, The IL-10 levels in the serum and supernatant were increased by given BMSCs and further increase by PGE2 over-expressed BMSCs, but decreased markedly by PGE2 silenced BMSCs. Furthermore, extracellular signal-regulated kinase 1 (ERK1) inhibitor reduced IL-10 production in KCs and blocked the inhibitory effect of PGE2 on the activation of the NLRP3 inflammasome. Our data reveal a novel mechanism of BMSC-mediated suppression of the activation of KCs through the secretion of PGE2 by BMSCs, which promotes KCs to secrete IL-10, leading to the inhibition of the NLRP3 inflammasome in KCs.

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.

Method validation of analytical method for 12 flavonol glycosides in foods using ultra high-performance liquid chromatography coupled with photodiode array detection

An analytical method for the simultaneous determination of 12 flavonol glycosides in buckwheat, black tea, and wild parsley using ultra high-performance liquid chromatography (UHPLC) coupled with a simple liquid extraction method using dimethyl sulfoxide (DMSO) was validated in precision, accuracy, and linearity. The UHPLC separation of target compounds was performed on a C18 column using a photodiode array (PDA) detector and the wavelength was fixed at 350 nm. The recovery values for flavonol glycosides ranged from 85.44 to 108.79%. The limits of detection and limits of quantification were less than 0.32 mg/kg and less than 0.97 mg/kg, respectively. The intraday and interday precisions were less than 13.69% for all the test samples. This method coupled with UHPLCPDA detection could be expected to provide more convenient sample preparation than conventional methods in the tested foods.