The effect of tai chi intervention on NLRP3 and its related antiviral inflammatory factors in the serum of patients with pre-diabetes.

Background: NLRP3 inflammasome and its related antiviral inflammatory factors have been implicated in the pathogenesis of type 2 diabetes mellitus (T2DM) and insulin resistance, but its contribution to pre-diabetes remains poorly understood. Objective: To investigate the effects and the potential mechanism of Tai Chi intervention on NLRP3 inflammasome and its related inflammatory factors in the serum of middle-aged and older people with pre-diabetes mellitus (PDM). Methods: 40 pre-diabetic subjects were divided into a pre-diabetic control group (PDM-C group, N=20) and a Tai Chi group (PDM-TC group, N=20) by random number table. 10 normoglycemic subjects (NG) were selected as controls. We measured clinical metabolic parameters and collected blood samples before and after the 12 weeks of Tai Chi intervention. Antiviral inflammatory factors in serum were detected by enzyme-linked immunosorbent assay. Results: The blood glucose, insulin resistance, and inflammation in PDM groups were higher than those in the NG group (P<0.05 and P<0.01, respectively). The results also suggested that 12 weeks of Tai Chi intervention could reduce body weight, blood pressure, blood glucose, insulin resistance, blood lipid, and the expressions of serum inflammatory factors in the pre-diabetic population. Conclusion: Tai Chi intervention may improve blood glucose, lipid levels, and insulin resistance in middle-aged and elderly pre-diabetic patients by reducing the level of NLRP3 inflammasome and its related inflammatory factors.

Inflammasome Activation in Parkinson's Disease.

Chronic sterile inflammation and persistent immune activation is a prominent pathological feature of Parkinson's disease (PD). Inflammasomes are multi-protein intracellular signaling complexes which orchestrate inflammatory responses in immune cells to a diverse range of pathogens and host-derived signals. Widespread inflammasome activation is evident in PD patients at the sites of dopaminergic degeneration as well as in blood samples and mucosal biopsies. Inflammasome activation in the nigrostriatal system is also a common pathological feature in both neurotoxicant and α-synuclein models of PD where dopaminergic degeneration occurs through distinct mechanisms. The NLRP3 (NLR Family Pyrin Domain Containing 3) inflammasome has been shown to be the primary driver of inflammatory neurotoxicity in PD and other neurodegenerative diseases. Chronic NLRP3 inflammasome activation is triggered by pathogenic misfolded α-synuclein aggregates which accumulate and spread over the disease course in PD. Converging lines of evidence suggest that blocking inflammasome activation could be a promising therapeutic strategy for disease modification, with both NLRP3 knockout mice and CNS-permeable pharmacological inhibitors providing robust neuroprotection in multiple PD models. This review summarizes the current evidence and knowledge gaps around inflammasome activation in PD, the pathological mechanisms by which persistent inflammasome activation can drive dopaminergic degeneration and the therapeutic opportunities for disease modification using NLRP3 inhibitors.

Expression and Mechanism of TXNIP/NLRP3 Inflammasome in Sciatic Nerve of Type 2 Diabetic Rats.

Objective: To determine the expression profiling and mechanism of thioredoxin-interacting protein (TXNIP)/nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome pathway in sciatic nerve (SN) of type 2 diabetes mellitus (T2DM) rats. Methods: Ten out of the 35 healthy SD rats (specific pathogen free) purchased were randomized into the control group, while the others were established a T2DM model by feeding a high-fat and high-sugar diet plus laparoscopic injection of 1% streptozotocin (STZ). The successfully modeled rats were subgrouped into two arms: a DM group with 10 rats and a resveratrol- (RES-) treated DM intervention group with 11 rats. Normal saline to control and DM groups. Alterations in fasting blood glucose (FBG) and body weight (BW) at different time points after administration were observed. Sciatic nerve conduction velocity (SNCV) and mechanical pain threshold (MPT) were measured. TXNIP, NLRP3, caspase-1, and interleukin- (IL-) 1ß levels in rat SN tissue were determined. Results: DM group rats showed higher FBG and lower BW than control rats at different time points (P < 0.05). The FBG of DM intervention group at 2, 4, and 6 weeks after administration was lower, and the BW at 4 and 6 weeks after dosing was higher than DM group. Higher MPT and SNCV were determined in DM intervention group versus DM group (P < 0.05). DM group rats had disordered, swollen, and dissolved SN myelin sheath structure; TXNIP inhibition led to a small amount of nerve myelin fragments and mild pathological changes. Lower TXNIP, NLRP3, caspase-1, and IL-1ß protein levels were found in DM intervention group versus DM group (P < 0.05). Conclusion: The pathogenesis of peripheral neuropathy in T2DM rats may be linked to TXNIP/NLRP3 inflammasome pathway activation, indicating the potential of this pathway as a therapeutic target for diabetic peripheral neuropathy (DPN).

[Atherosclerosis, an inflammatory disease]. / L'athérosclérose, une maladie inflammatoire.

Chronic inflammation is recognized as a contributing factor to the development, progression and complications of atherosclerosis. The inflammatory nature of atherosclerosis has been proven by the presence of inflammatory cells, cytokines and chemokines at all stages of the disease. There is a widely accepted association between cardiovascular events and serum inflammatory markers, such as CRP, IL-6 and IL-1? produced via the inflammasome pathway. The involvement of inflammatory processes in atherosclerosis and progress in the therapeutic strategy are detailed in the article.

: L'inflammation chronique est reconnue comme un facteur contribuant au développement, à la progression et aux complications de l'athérosclérose. La nature inflammatoire de l'athérosclérose a été prouvée par la présence de cellules inflammatoires, de cytokines et chimiokines à tous les stades de celle-ci. Il existe une association largement acceptée entre les événements cardiovasculaires et les marqueurs inflammatoires sériques tels que la CRP, l'IL-6 et l'IL-1? produite via la voie de l'inflammasome. L'implication des processus inflammatoires dans l'athérosclérose et les progrès dans la stratégie thérapeutique sont détaillés dans l'article.

TLR4 aggravates microglial pyroptosis by promoting DDX3X-mediated NLRP3 inflammasome activation via JAK2/STAT1 pathway after spinal cord injury.

BACKGROUND: Toll-like receptor 4 (TLR4) participates in the initiation of neuroinflammation in various neurological diseases, including central nervous system injuries. NLR family pyrin domain containing 3 (NLRP3) inflammasome-mediated microglial pyroptosis is crucial for the inflammatory response during secondary spinal cord injury (SCI). However, the underlying mechanism by which TLR4 regulates NLRP3 inflammasome activation and microglial pyroptosis after SCI remains uncertain. METHODS: We established an in vivo mouse model of SCI using TLR4-knockout (TLR4-KO) and wild-type (WT) mice. The levels of pyroptosis, tissue damage and neurological function recovery were evaluated in the three groups (Sham, SCI, SCI-TLR4-KO). To identify differentially expressed proteins, tandem mass tag (TMT)-based proteomics was conducted using spinal cord tissue between TLR4-KO and WT mice after SCI. For our in vitro model, mouse microglial BV2 cells were exposed to lipopolysaccharides (1 µg/ml, 8 h) and adenosine triphosphate (ATP) (5 mM, 2 h) to induce pyroptosis. A series of molecular biological experiments, including Western blot (WB), real-time quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), immunofluorescence (IF), immunohistochemical (IHC), chromatin immunoprecipitation (ChIP), Dual-Luciferase Reporter assay (DLA) and co-immunoprecipitation (Co-IP), were performed to explore the specific mechanism of microglial pyroptosis in vivo and in vitro. RESULTS: Our results indicated that TLR4 promoted the expression of dead-box helicase 3 X-linked (DDX3X), which mediated NLRP3 inflammasome activation and microglial pyroptosis after SCI. Further analysis revealed that TLR4 upregulated the DDX3X/NLRP3 axis by activating the JAK2/STAT1 signalling pathway, and importantly, STAT1 was identified as a transcription factor promoting DDX3X expression. In addition, we found that biglycan was increased after SCI and interacted with TLR4 to jointly regulate microglial pyroptosis through the JAK2/STAT1/DDX3X/NLRP3 axis after SCI. CONCLUSION: Our study preliminarily identified a novel mechanism by which TLR4 regulates NLRP3 inflammasome-mediated microglial pyroptosis in response to SCI-providing a novel and promising therapeutic target for SCI.

The NLRP3 Inflammasome Inhibitor Dapansutrile Attenuates Cyclophosphamide-Induced Interstitial Cystitis.

Interstitial cystitis (IC)/bladder pain syndrome (BPS), hereafter referred together as IC, is a clinical syndrome characterized by sterile inflammation in the bladder. While the etiology and pathophysiology of IC remain unclear, it may involve autoimmunity in light of the significant role played by the NLRP3 inflammasome. However, the effect of NLRP3 inhibitors including dapansutrile (Dap) on IC had not been explored previously. Here, we investigated the effect of Dap in the cyclophosphamide (CYP)-induced experimental mouse model of IC, which results in functional and histological alterations confined to the urinary bladder (UB) comparable to that of clinical IC. CYP-induced mice treated with Dap exhibited improved UB pathology and reductions in inflammation scores and the frequency and the number of mast cells and neutrophils, relative to mice that received CYP alone. Dap- and CYP-treated mice also exhibited infiltration of T cells in the spleen and iliac lymph nodes (ILNs) and a concurrent significant decrease (p<0.01) in CXCR3+CD8+ T cells in the UB, induction of systemic and mucosal dendritic cells (DCs), and reduced levels of systemic proinflammatory cytokines, as compared to CYP alone. We also observed decreases in the expression of several signaling pathways regulators, including interleukin-1 beta (IL-1ß), NLRP3, caspase-1, nuclear factor kappa B (NF-κB), and inducible nitric oxide synthase (iNOS) in the UB of CYP- and Dap-treated mice, relative to those receiving CYP alone. Taken together, these results suggest that Dap suppresses IC through the reduction of CXCR3+T cells, mast cells, and neutrophils in the UB and induces DCs as a protective measure. The present study identifies the mechanisms underlying the amelioration of IC by the NLRP3 inhibitor Dap and may provide an avenue for a potential therapeutic agent for the treatment of IC.

Long non-coding RNA SNHG5 mediates periodontal inflammation through the NF-κB signalling pathway.

AIM: We investigated the role of long non-coding RNAs and small nucleolar RNA host gene 5 (SNHG5) in the pathogenesis of periodontitis. MATERIALS AND METHODS: A ligature-induced periodontitis mouse model was established, and gingival tissues were collected from patients with periodontitis and healthy controls. Inflammatory cytokines were detected using quantitative reverse transcription-polymerase chain reaction and western blotting analyses. Direct interactions between SNHG5 and p65 were detected by RNA pull-down and RNA immunoprecipitation assays. Micro-computed tomography, haematoxylin and eosin staining, and immunohistochemical staining were used to measure periodontal bone loss. RESULTS: SNHG5 expression was down-regulated in human and mouse periodontal tissues compared to that in the healthy controls. In vitro experiments demonstrated that SNHG5 significantly ameliorated tumour necrosis factor α-induced inflammation. Mechanistically, SNHG5 directly binds to the nuclear factor-kappa B (NF-κB) p65 subunit and inhibits its translocation, thereby suppressing the NF-κB signalling pathway activation and reducing the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing three inflammasome expression. Locally injecting si-SNHG5 aggravated the periodontal destruction. CONCLUSION: This study revealed that SNHG5 mediates periodontal inflammation through the NF-κB signalling pathway, providing a potential therapeutic target for periodontitis treatment.

[Effects of NLRP3-mediated pyroptosis on olfaction dysfunction in allergic rhinitis].

Objective: To explore the relationship between NLRP3-mediated pyroptosis and olfactory dysfunction (OD) in allergic rhinitis (AR), and to evaluate the therapeutic potential of CY-09, a selective NLRP3 inhibitor for OD. Methods: An AR mouse model was established with ovalbumin, and the olfactory function of AR mice was detected by the buried food pellet test. Mice with OD were intraperitoneally injected with CY-09 or saline. The activation of microglia and astrocytes in olfactory bulb was detected by immunohistochemistry. The expression level of pyroptosis associated protein was detected by Western blot. The level of pyroptosis associated proinflammatory factor mRNA was determined by real-time PCR. SPSS 24.0 software was used for statistical analysis. Results: After the test, ovalbumin successfully established AR mice model, in which 52.5% (21/40) of them showed OD. The number of activated microglia and astroglia in olfactory bulb tissue in OD group were more than those in non-OD group (all P<0.05). Compared with the control group, the expression of NLRP3, caspase-1 and gasdermin D (GSDMD) was significantly increased in the olfactory bulb of the OD group (all P<0.05). CY-09 could significantly reduce the level of NLRP3, caspase-1, GSDMD, IL-1ß and IL-18 expression, and inhibite the activation of microglia and astrocytes in the olfactory bulb tissues (all P<0.05). Conclusion: NLRP3-mediated pyroptosis is closely related to the OD associated with AR. CY-09 could improve the olfactory function in AR mice, which may be related to blocking the NLRP3-mediated pyroptosis.

Berberine protects diabetic nephropathy by suppressing epithelial-to-mesenchymal transition involving the inactivation of the NLRP3 inflammasome.

Accumulating evidence has implicated that berberine (BBR) has a beneficial effect on diabetic kidney disease (DKD), but its mechanism is not clear. The aim of this study was to assess whether berberine could alleviate tubulointerstitial fibrosis and attenuate epithelial-to-mesenchymal transition (EMT) and its possible molecular mechanism. High-fat diet (HFD) followed by injection of STZ was used to induce diabetic rats in vivo. After the onset of diabetes, rats were treated with either BBR or saline for 12 weeks. In vitro, the human renal proximal tubular epithelial cell line (HK-2) was exposed to high glucose, with or without BBR. The influence of berberine on renal tubulointerstitial histological changes, markers of epithelial-to-mesenchymal transition (EMT) and (NOD-like receptor pyrin domain-containing protein 3) NLRP3 inflammasome expression were examined. Results showed that in vivo, BBR could significantly ameliorate microalbumin and renal pathologic changes in diabetic rats. Immunofluorescence showed that BBR could inhibit EMT. Furthermore, BBR could down-regulate the level of the NLRP3 inflammasome in diabetic rats. Consistently, in vitro, BBR suppressed high glucose-induced EMT and activation of NLRP3 inflammasome in HK-2. Our study demonstrated that BBR could inhibit high glucose-induced EMT and renal interstitial fibrosis by suppressing the NLRP3 inflammasome. BBR might be used as a novel drug to ameliorate tubulointerstitial fibrosis in DKD.

Inflammation and atherosclerosis: signaling pathways and therapeutic intervention.

Atherosclerosis is a chronic inflammatory vascular disease driven by traditional and nontraditional risk factors. Genome-wide association combined with clonal lineage tracing and clinical trials have demonstrated that innate and adaptive immune responses can promote or quell atherosclerosis. Several signaling pathways, that are associated with the inflammatory response, have been implicated within atherosclerosis such as NLRP3 inflammasome, toll-like receptors, proprotein convertase subtilisin/kexin type 9, Notch and Wnt signaling pathways, which are of importance for atherosclerosis development and regression. Targeting inflammatory pathways, especially the NLRP3 inflammasome pathway and its regulated inflammatory cytokine interleukin-1ß, could represent an attractive new route for the treatment of atherosclerotic diseases. Herein, we summarize the knowledge on cellular participants and key inflammatory signaling pathways in atherosclerosis, and discuss the preclinical studies targeting these key pathways for atherosclerosis, the clinical trials that are going to target some of these processes, and the effects of quelling inflammation and atherosclerosis in the clinic.

The inflammasome as a therapeutic target for myopericardial diseases.

Myopericardial diseases are relatively common in clinical practice although often neglected due to the limited availability of treatments and evidence to support management strategies. However in the past ten years, growing evidence has improved our knowledge of the pathophysiology of myopericardial diseases and first clinical trials have highlighted the importance of inflammation as therapeutic target developing first steps toward a personalized approach also in this field. The NLRP3 (NACHT, leucine-rich repeat, and pyrin domain-containing protein 3) inflammasome is a protein complex that functions as a platform for rapid induction of the inflammatory response to infection or sterile injury through pro-inflammatory cytokines, now recognized as a new important therapeutic target for myopericardial diseases. Colchicine is an old drug that acts as non-specific inhibitor of the inflammasome and could be a useful and inexpensive option in clinical practice and it is currently registered for pericarditis in some European countries (e.g., Italy, Austria). Anti-interleukin-1 (IL-1) agents (anakinra and rilonacept) appear to be a major advance in medical therapy of recurrent pericarditis and could be a therapeutic option also for myocarditis if confirmed in additional studies. In this review, we provide an update on the inflammasome as therapeutic target for myopericardial diseases, a significant advance in medical therapy for these diseases in the last five years.

Advances in pharmacotherapy for acute and recurrent pericarditis.

INTRODUCTION: Aspirin or non-steroidal anti-inflammatory drugs (NSAIDs) and colchicine are first-line treatments for acute and recurrent pericarditis. Drugs blocking the NACHT, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome/interleukin-1ß (IL-1ß) axis are beneficial in patients with multiple recurrences. AREAS COVERED: In this review, the role of the NLRP3 inflammasome/IL-1ß axis in the pathophysiology of pericarditis is discussed. Updates about novel therapies targeting IL-1 for recurrent pericarditis (RP) and practical considerations for their use are provided. EXPERT OPINION: IL-1 inhibitors have been increasingly studied for RP in recent years. NLRP3 inflammasome is a key mediator in the pathophysiology of RP. IL-1ß, its main product, can sustain its own production and feeds local and systemic inflammation. Randomized clinical trials testing anakinra (a recombinant form of the IL-1 receptor antagonist blocking IL-1α and IL-1ß) and rilonacept (an IL-1α and IL-1ß trap) have shown that IL-1 blockade reduces recurrences. These trials also helped in phenotyping patients with RP. Patients with multiple recurrences and signs of pericardial and/or systemic inflammation might benefit from IL-1 blockers in order to interrupt cyclic flares of auto-inflammation. Given this evidence, guidelines should consider incorporating IL-1 blockers.

A selective inhibitor of the NLRP3 inflammasome as a potential therapeutic approach for neuroprotection in a transgenic mouse model of Huntington's disease.

BACKGROUND: Huntington's disease (HD) is a neurodegenerative disorder caused by the expansion of the CAG repeat in the huntingtin (HTT) gene. When the number of CAG repeats exceeds 36, the translated expanded polyglutamine-containing HTT protein (mutant HTT [mHTT]) interferes with the normal functions of many cellular proteins and subsequently jeopardizes important cellular machineries in major types of brain cells, including neurons, astrocytes, and microglia. The NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome, which comprises NLRP3, ASC, and caspase-1, is involved in the activation of IL-1ß and IL-18 and has been implicated in various biological functions. Although the existence of the NLRP3 inflammasome in the brain has been documented, the roles of the NLRP3 inflammasome in HD remain largely uncharacterized. MCC950 is a highly selective and potent small-molecule inhibitor of NLRP3 that has been used for the treatment of several diseases such as Alzheimer's disease. However, whether MCC950 is also beneficial in HD remains unknown. Therefore, we hypothesized that MCC950 exerts beneficial effects in a transgenic mouse model of HD. METHODS: To evaluate the effects of MCC950 in HD, we used the R6/2 (B6CBA-Tg[HDexon1]62Gpb/1J) transgenic mouse model of HD, which expresses exon 1 of the human HTT gene carrying 120 ± 5 CAG repeats. Male transgenic R6/2 mice were treated daily with MCC950 (10 mg/kg of body weight; oral administration) or water for 5 weeks from the age of 7 weeks. We examined neuronal density, neuroinflammation, and mHTT aggregation in the striatum of R6/2 mice vs. their wild-type littermates. We also evaluated the motor function, body weight, and lifespan of R6/2 mice. RESULTS: Systematic administration of MCC950 to R6/2 mice suppressed the NLRP3 inflammasome, decreased IL-1ß and reactive oxygen species production, and reduced neuronal toxicity, as assessed based on increased neuronal density and upregulation of the NeuN and PSD-95 proteins. Most importantly, oral administration of MCC950 increased neuronal survival, reduced neuroinflammation, extended lifespan, and improved motor dysfunction in R6/2 mice. CONCLUSIONS: Collectively, our findings indicate that MCC950 exerts beneficial effects in a transgenic mouse model of HD and has therapeutic potential for treatment of this devastating neurodegenerative disease.

Colchicine prevents disease progression in viral myocarditis via modulating the NLRP3 inflammasome in the cardiosplenic axis.

AIM: The acute phase of a coxsackievirus 3 (CVB3)-induced myocarditis involves direct toxic cardiac effects and the systemic activation of the immune system, including the cardiosplenic axis. Consequently, the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing-3 (NLRP3) inflammasome pathway is activated, which plays a role in disease pathogenesis and progression. The anti-inflammatory drug colchicine exerts its effects, in part, via reducing NLRP3 activity, and has been shown to improve several cardiac diseases, including acute coronary syndrome and pericarditis. The aim of the present study was to evaluate the potential of colchicine to improve experimental CVB3-induced myocarditis. METHODS AND RESULTS: C57BL6/j mice were intraperitoneally injected with 1 × 105 plaque forming units of CVB3. After 24 h, mice were treated with colchicine (5 µmol/kg body weight) or phosphate-buffered saline (PBS) via oral gavage (p.o.). Seven days post infection, cardiac function was haemodynamically characterized via conductance catheter measurements. Blood, the left ventricle (LV) and spleen were harvested for subsequent analyses. In vitro experiments on LV-derived fibroblasts (FB) and HL-1 cells were performed to further evaluate the anti-(fibro)inflammatory and anti-apoptotic effects of colchicine via gene expression analysis, Sirius Red assay, and flow cytometry. CVB3 + colchicine mice displayed improved LV function compared with CVB3 + PBS mice, paralleled by a 4.7-fold (P < 0.01) and 1.7-fold (P < 0.001) reduction in LV CVB3 gene expression and cardiac troponin-I levels in the serum, respectively. Evaluation of components of the NLRP3 inflammasome revealed an increased percentage of apoptosis-associated speck-like protein containing a CARD domain (ASC)-expressing, caspase-1-expressing, and interleukin-1ß-expressing cells in the myocardium and in the spleen of CVB3 + PBS vs. control mice, which was reduced in CVB3 + colchicine compared with CVB3 + PBS mice. This was accompanied by 1.4-fold (P < 0.0001), 1.7-fold (P < 0.0001), and 1.7-fold (P < 0.0001) lower numbers of cardiac dendritic cells, natural killer cells, and macrophages, respectively, in CVB3 + colchicine compared with CVB3 + PBS mice. A 1.9-fold (P < 0.05) and 4.6-fold (P < 0.001) reduced cardiac gene expression of the fibrotic markers, Col1a1 and lysyl oxidase, respectively, was detected in CVB3 + colchicine mice compared with CVB3 + PBS animals, and reflected by a 2.2-fold (P < 0.05) decreased Collagen I/III protein ratio. Colchicine further reduced Col3a1 mRNA and collagen protein expression in CVB3-infected FB and lowered apoptosis and viral progeny release in CVB3-infected HL-1 cells. In both CVB3 FB and HL-1 cells, colchicine down-regulated the NLRP3 inflammasome-related components ASC, caspase-1, and IL-1ß. CONCLUSIONS: Colchicine improves LV function in CVB3-induced myocarditis, involving a decrease in cardiac and splenic NLRP3 inflammasome activity, without exacerbation of CVB3 load.

Granulomatous Herpetic Encephalitis A Possible Role for Inflammasomes.

BACKGROUND: Granulomatous herpetic encephalitis is a rare inflammatory complication of acute herpes simplex encephalitis. METHODS: We describe 3 cases of granulomatous herpetic encephalitis in children arising between 1 to 10 years after the initial presentation with acute herpes simplex encephalitis. We focus on the clinical course and neuroimaging phenotype with a discussion of possible mechanisms underpinning this entity. RESULTS: The clinical course was highly variable. However, the dominant neuroimaging phenotype in each of our cases was that of confluent gyriform cortical enhancement with predominantly solid foci of enhancement in the subjacent white matter +/- deep gray nuclei. Cerebrospinal fluid was negative for herpes simplex virus DNA in all cases. All 3 cases required brain biopsy to help establish the diagnosis. CONCLUSIONS: Increased recognition of granulomatous herpetic encephalitis in children will facilitate earlier diagnosis and treatment. Although the exact role played by the host immune response, genetics, and environment in determining the different outcomes of herpes simplex encephalitis remains to be determined, we postulate a role for inflammasome dysregulation in this entity.

Dysregulation of the NLRP3 Inflammasome in Diabetic Retinopathy and Potential Therapeutic Targets.

Diabetic Retinopathy (DR) is an insidious neurovascular disorder secondary to chronic glycemic dysregulation in elderly diabetic patients. In the later stages of DR, the disease manifests as fluid infiltrating the macula, culminating in the leading cause of irreversible visual impairment in working age adults. With the current mainstay treatments preoccupied with slowing down the progression of DR, this presents an unsustainable solution from both an economic and quality of life perspective. Although the exact mechanisms by which hyperglycemia leads to retinal tissue insult are unknown, the evidence suggests that chronic low-grade inflammation in diabetic eye is in part driving the constellation of symptoms present in DR. Of the innate immune system within the eye, the NLR Family Pyrin Domain Containing 3 Inflammasome (NLRP3) has been identified in retinal cells as a causal factor in the pathogenesis of DR. Multiple pathways appear to be present in the diabetic eye that instigate prolonged activation of the NLRP3 which subsequently exerts its deleterious effects by upregulating the release of Interleukin-1Beta and Interleukin-18. In this review, we highlight the current understanding of the pathophysiology of DR, the dysregulation of the NLRP3 secondary to hyperglycemic stress in retinal cells, and novel therapeutic targets to alleviate overactivation of the inflammasome.

A novel nutritional mixture, MBN, prevents memory impairment via inhibiting NLRP3 inflammasome formation in 5xFAD transgenic mice.

OBJECTIVES: Amyloid beta (Aß)-induced abnormal neuroinflammation is recognized as a major pathological factor of Alzheimer's disease (AD), which results in memory impairment. Inhibition of excessive neuroinflammation mediated by Aß is considered a promising strategy to ameliorate AD symptoms. To regulate the inflammatory response, nutritional and dietary supplements have been used for centuries. Based on this idea, we investigated whether MBN, a novel nutritional mixture including cassia bark, turmeric root, and ginkgo leaf, can prevent AD progression through neuroinflammatory regulation. METHODS: MBN (10, 30, or 100 µg/ml) and Aß1-42 monomer were incubated together, and the degree of Aß aggregation was measured using Thioflavin T assay. The effects of MBN on Aß pathology in vivo were evaluated by orally administering MBN (40 mg/kg/day for 16 weeks) to five familial AD (5xFAD) mice. RESULTS: We found that treatment with MBN inhibited Aß aggregation in vitro. Next, MBN treatment significantly inhibited the activation of microglia induced by aggregated Aß in 5xFAD mice. Caspase-1 activation, which plays an important role in the maturation of interleukin-1ß, was markedly reduced by MBN. We also found that oral administration of MBN in 5xFAD mice alleviated memory decline. Taken together, our findings demonstrate that MBN suppresses neuroinflammation by downregulating the caspase-1 expression, thereby ameliorating memory impairment in 5xFAD mice. DISCUSSION: Based on these results, we suggest that MBN may be a preventive and therapeutic supplement for AD through the regulation of neuroinflammation.

Upregulated NLRP3 inflammasome activation is attenuated by anthocyanins in patients with nonalcoholic fatty liver disease: A case-control and an intervention study.

OBJECTIVES: Despite the recent attention focused on the roles of the NLRP3 inflammasome in the pathogenesis of metabolic and inflammatory diseases, little is known about the activation status of NLRP3 inflammasome in patients with nonalcoholic fatty liver disease (NAFLD). The present study aimed to investigate whether inflammasomes activation is upregulated in patients with NAFLD and the upregulation can be attenuated by anthocyanins, which are polyphenols with known anti-inflammatory activities. METHODS: This study included a case-control study and a randomized controlled intervention trial. In the first part, NAFLD patients and healthy controls were recruited from a cohort of railroad workers. In the second part, NAFLD patients were randomly assigned to receive either capsules of anthocyanins (320 mg daily) or placebo for 12 weeks. A series of genes and factors associated with activation of NLRP3 inflammasome in subjects' plasma and peripheral blood mononuclear cells (PBMCs) were analyzed. RESULTS: Compared with healthy controls, the mRNA levels of NLRP3 inflammasome components (NLRP3, caspase-1, interleukin (IL)-1ß, and IL-18) were significantly upregulated in the PBMCs of NAFLD patients. Consistently, plasma levels of mature IL-1ß and IL-18 in NAFLD patients were significantly higher than in controls. After anthocyanin administration, both mRNA expression of NLRP3 inflammasome components (caspase-1, IL-1ß, and IL-18) in PBMCs and plasma levels of IL-1ß and IL-18 decreased dramatically in NAFLD patients compared with controls. CONCLUSIONS: This study has demonstrated that the activation of NLRP3 inflammasome is highly increased in NAFLD patients, but it can be markedly suppressed by anthocyanins, which provides a rationale for the development of anti-inflammatory therapies in NAFLD.

A novel small molecular NLRP3 inflammasome inhibitor alleviates neuroinflammatory response following traumatic brain injury.

BACKGROUND: Neuroinflammation is an essential player in many neurological diseases including traumatic brain injury (TBI). Recent studies have identified that inflammasome complexes are responsible for inflammatory responses in many pathological conditions. Inflammasomes are intracellular multiprotein complexes which regulate the innate immune response, activation of caspase-1, production of pro-inflammatory cytokines IL-1ß and IL-18, and induction of cell death (pyroptosis). Among inflammasome family members, the nucleotide-binding domain leucine-rich repeats family protein 3 (NLRP3) is the most extensively studied and its activation is induced following TBI. As a novel target, drug development targeting the formation and activation of NLRP3 inflammasome is a prospective therapy for TBI. We have recently developed a small molecule JC124 with specificity on NLRP3 inflammasome. In this study, we explored the therapeutic value of JC124 for TBI treatment. METHODS: Adult male Sprague-Dawley rats were subjected to a moderate cortical impact injury. Following TBI, animals received 4 doses of JC124 treatment with the first dose starting at 30 min, the second dose at 6 h after TBI, the third and fourth doses at 24 or 30 h following TBI, respectively. Animals were sacrificed at 2 days post-injury. Brain tissues were processed either for ELISA and western blotting analysis for inflammatory response, or for histological examination to assess degenerative neurons, acute inflammatory cell response and lesion volume. RESULTS: We found that post-injury treatment with JC124 significantly decreased the number of injury-induced degenerating neurons, inflammatory cell response in the injured brain, and cortical lesion volume. Injured animals treated with JC124 also had significantly reduced protein expression levels of NLRP3, ASC, IL-1 beta, TNFα, iNOS, and caspase-1. CONCLUSION: Our data suggest that our novel NLRP3 inhibitor has a specific anti-inflammatory effect to protect the injured brain following TBI.

Inflammasome: A Double-Edged Sword in Liver Diseases.

Inflammasomes have emerged as critical innate sensors of host immune that defense against pathogen infection, metabolism syndrome, cellular stress and cancer metastasis in the liver. The assembly of inflammasome activates caspase-1, which promotes the maturation of interleukin-1ß (IL-1ß) and interleukin-18 (IL-18), and initiates pyroptotic cell death (pyroptosis). IL-18 exerts pleiotropic effects on hepatic NK cells, priming FasL-mediated cytotoxicity, and interferon-γ (IFN-γ)-dependent responses to prevent the development of liver diseases. However, considerable attention has been attracted to the pathogenic role of inflammasomes in various acute and chronic liver diseases, including viral hepatitis, nanoparticle-induced liver injury, alcoholic and non-alcoholic steatohepatitis. In this review, we summarize the latest advances on the physiological and pathological roles of inflammasomes for further development of inflammasome-based therapeutic strategies for human liver diseases.