NOD-like Receptor Pyrin Domain-containing Protein 3 Inflammasome Research Articles

Lycopene alleviates zearalenone-induced oxidative stress, apoptosis, and NLRP3 inflammasome activation in mice kidneys

The aim of this study was to investigate the protective effects of lycopene on renal damage caused by zearalenone (ZEN). Male Kunming mice were treated daily for 4 weeks by intragastric administration with 40 mg/kg ZEN in the presence or absence of lycopene (2.5 or 5 mg/kg). The results showed that lycopene markedly alleviated the damage of renal structure and function in mice induced by ZEN, as indicated by the reduced degree of pathological damage and the decreased levels of urea nitrogen and creatinine. Meanwhile, results of dihydroethidine (DHE) staining and biochemical markers revealed that ZEN exposure notably increased the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), decreased the level of GSH, and reduced the activities of catalase (CAT) and superoxide dismutase (SOD). Administration of lycopene alleviated the increased oxidative stress induced by ZEN. Moreover, ZEN ingestion notably resulted in apoptosis, increased the protein levels of BCL2 associated X protein (Bax) and cleaved caspase-3, and decreased the protein levels of apoptosis regulator Bcl-2 (Bcl-2), which were reversed by lycopene intervention. Results of immunofluorescence demonstrated that lycopene reversed ZEN-induced the upregulation of NOD-like receptor pyrin domain-containing protein 3 (NLRP3), Caspase-1, and interleukin-1 beta (IL-1β) in mice kidneys. Lycopene supplementation could alleviate ZEN-induced renal toxicity by inhibiting oxidative stress, apoptosis, and NLRP3 inflammasome activation.

The PGC-1α/ERRα/ULK1 Pathway Contributes to Perioperative Neurocognitive Disorders by Inducing Mitochondrial Dysfunction and Activating NLRP3 Inflammasome in Aged Mice

Perioperative neurocognitive disorders (PND) are intractable, indistinct, and considerably diminish the postoperative quality of life of patients. It has been proved that Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) was involved in neurodegenerative diseases by regulating mitochondrial biogenesis. The underlying mechanisms of PGC-1α and Nod-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome in PND are not well understood. In this study, we constructed a model of laparotomy in aged mice, and then examined the cognition changes with novel object recognition tests and fear condition tests. The protein levels of PGC-1α and NLRP3 in the hippocampus were detect after surgery. Our results showed that NLRP3 and downstream PI3K/AKT pathway expressions were augmented in the hippocampus after surgery, whereas, the expressions of PGC-1α/estrogen-related receptor α (ERRα)/Unc-51-like autophagy activating kinase 1 (ULK1) pathway were diminished after surgery. In addition, we found that NLRP3 was mainly co-localized with neurons in the hippocampus, and synaptic-related proteins were reduced after surgery. At the same time, transmission electron microscopy (TEM) showed that mitochondria were impaired after surgery. Pharmacological treatment of MCC950, a selective NLRP3 inhibitor, effectively alleviated PND. Activation of PGC-1α with ZLN005 significantly ameliorated PND by enhancing the PGC-1α/ERRα/ULK1 signaling pathway, and further suppressing NLRP3 activation. As a result, we conclude that suppression of the PGC-1α/ERRα/ULK1 signaling pathway is the primary mechanism of PND which caused mitochondrial dysfunction, and activated NLRP3 inflammasome and downstream PI3K/AKT pathway, eventually improved cognitive dysfunction.

Interaction of obesity and proteins associated with the NLRP3 inflammasome following mild traumatic brain injury

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome has been associated with worse outcomes from severe traumatic brain injury (TBI). The NLRP3 inflammasome is also strongly associated with other pro-inflammatory conditions, such as obesity. Little is known about the potential effect of mild TBI (mTBI) on the NLRP3 inflammasome and the extent to which modifying factors, such as obesity, may augment the inflammatory response to mTBI. The purpose of this study was to evaluate the association of NLRP3 inflammasome proteins with obese body mass index (BMI ≥ 30) within 24 h of mTBI after presenting to a level 1 trauma center emergency department. This is a secondary analysis of prospectively enrolled patients with mTBI who presented to the emergency department of one U.S. Level 1 trauma center from 2013 to 2018 (n = 243). A series of regression models were built to evaluate the association of NLRP3 proteins obtained from blood plasma within 24 h of injury and BMI as well as the potential interaction effect of higher BMI with NLRP3 proteins (n = 243). A logistic regression model revealed a significant association between IL-18 (p < 0.001) in mTBI patients with obese BMI compared to mTBI patients with non-obese BMI (< 30). Moderation analyses revealed statistically significant interaction effects between apoptotic speck-like protein (ASC), caspase-1, IL-18, IL-1β and obese BMI which worsened symptom burden, quality of life, and physical function at 2 weeks and 6 months post-injury. Higher acute concentrations of IL-1β in the overall cohort predicted higher symptoms at 6-months and worse physical function at 2-weeks and 6-months. Higher acute concentrations of IL-18 in the overall cohort predicted worse physical function at 6-months. In this single center mTBI cohort, obese BMI interacted with higher acute concentrations of NLRP3 inflammasome proteins and worsened short- and long-term clinical outcomes.

Pharmacological Analysis of NLRP3 Inflammasome Inhibitor Sodium [(1,2,3,5,6,7-Hexahydro-s-indacen-4-yl)carbamoyl][(1-methyl-1H-pyrazol-4-yl)({[(2S)-oxolan-2-yl]methyl})sulfamoyl]azanide in Cellular and Mouse Models of Inflammation Provides a Translational Framework.

Interleukin (IL)-1β is an apex proinflammatory cytokine produced in response to tissue injury and infection. The output of IL-1β from monocytes and macrophages is regulated not only by transcription and translation but also post-translationally. Release of the active cytokine requires activation of inflammasomes, which couple IL-1β post-translational proteolysis with pyroptosis. Among inflammasome platforms, NOD-like receptor pyrin domain-containing protein 3 (NLRP3) is implicated in the pathogenesis of numerous human disorders in which disease-specific danger-associated molecular patterns (DAMPS) are positioned to drive its activation. As a promising therapeutic target, numerous candidate NLRP3-targeting therapeutics have been described and demonstrated to provide benefits in the context of animal disease models. While showing benefits, published preclinical studies have not explored dose-response relationships within the context of the models. Here, the preclinical pharmacology of a new chemical entity, [(1,2,3,5,6,7-hexahydro-s-indacen-4-yl)carbamoyl][(1-methyl-1H-pyrazol-4-yl)({[(2S)-oxolan-2-yl]methyl})sulfamoyl]azanide (NT-0249), is detailed, establishing its potency and selectivity as an NLRP3 inhibitor. NT-0249 also is evaluated in two acute in vivo mouse challenge models where pharmacodynamic/pharmacokinetic relationships align well with in vitro blood potency assessments. The therapeutic utility of NT-0249 is established in a mouse model of cryopyrin-associated periodic syndrome (CAPS). In this model, mice express a human gain-of-function NLRP3 allele and develop chronic and progressive IL-1β-dependent autoinflammatory disease. NT-0249 dose-dependently reduced multiple inflammatory biomarkers in this model. Significantly, NT-0249 decreased mature IL-1β levels in tissue homogenates, confirming in vivo target engagement. Our findings highlight not only the pharmacological attributes of NT-0249 but also provide insight into the extent of target suppression that will be required to achieve clinical benefit.

METTL14 contributes to acute lung injury by stabilizing NLRP3 expression in an IGF2BP2-dependent manner

Acute lung injury (ALI) as well as its more severe form, acute respiratory distress syndrome (ARDS), frequently leads to an uncontrolled inflammatory response. N6-methyladenosine (m6A) modification was associated with the progression of several inflammatory diseases. However, the role of methyltransferase-like 14 (METTL14)-mediated m6A methylation in ALI/ARDS remains unclear. Here, we reported an increase in overall expression levels of m6A and METTL14 in circulating monocyte-derived macrophages recruited to the lung following ALI, which is correlated with the severity of lung injury. We further demonstrated the critical function of METTL14 in activating NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome in vitro and in mouse models of ALI/ARDS, and validated NLRP3 as the downstream target of METTL14 by the m6A RNA immunoprecipitation (MeRIP) and RIP assays. Mechanistically, METTL14-methylated NLRP3 transcripts were subsequently recognized by insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2), an m6A reader, which stabilized NLRP3 mRNA. Furthermore, we observed that IGF2BP2 knockdown diminished LPS-induced ALI in mice by downregulating NLRP3 expression. In summation, our study revealed that the molecular mechanism underlying the pathogenesis of ALI/ARDS involves METTL14-mediated activation of NLRP3 inflammasome in an IGF2BP2 dependent manner, thereby demonstrating the potential of METTL14 and IGF2BP2 as promising biomarkers and therapeutic targets for ALI/ARDS treatment.

The roles of ubiquitination and deubiquitination of NLRP3 inflammasome in inflammation-related diseases: A review.

The inflammatory response is a natural immune response that prevents microbial invasion and repairs damaged tissues. However, excessive inflammatory responses can lead to various inflammation-related diseases, posing a significant threat to human health. The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome is a vital mediator in the activation of the inflammatory cascade. Targeting the hyperactivation of the NLRP3 inflammasome may offer potential strategies for the prevention or treatment of inflammation-related diseases. It has been established that the ubiquitination and deubiquitination modifications of the NLRP3 inflammasome can provide protective effects in inflammation-related diseases. These modifications modulate several pathological processes, including excessive inflammatory responses, pyroptosis, abnormal autophagy, proliferation disorders, and oxidative stress damage. Therefore, this review discusses the regulation of NLRP3 inflammasome activation by ubiquitination and deubiquitination modifications, explores the role of these modifications in inflammation-related diseases, and examines the potential underlying mechanisms.

Takinib inhibits microglial M1 polarization and oxidative damage after subarachnoid hemorrhage by targeting TAK1-dependent NLRP3 inflammasome signaling pathway.

Transforming growth factor-β-activated kinase 1 (TAK1) positively regulates oxidative stress and inflammation in different diseases. Takinib, a novel and specific TAK1 inhibitor, has beneficial effects in a variety of disorders. However, the effects of takinib on early brain injury (EBI) after subarachnoid hemorrhage (SAH) and the underlying molecular mechanisms remain unknown. Our study showed that takinib administration significantly inhibited phosphorylated TAK1 expression after SAH. In addition, takinib suppressed M1 microglial polarization and promoted M2 microglial polarization. Furthermore, blockade of TAK1 by takinib reduced neuroinflammation, oxidative damage, brain edema, and neuronal apoptosis, and improved neurological behavior after SAH. Mechanistically, we revealed that TAK1 inhibition by takinib mitigated reactive oxygen species (ROS) production and ROS-mediated nod-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome activation. In contrast, NLRP3 activation by nigericin abated the neuroprotective effects of takinib against EBI after SAH. In general, our study demonstrated that takinib could protect against EBI by targeting TAK1-ROS-NLRP3 inflammasome signaling. Inhibition of TAK1 might be a promising option in the management of SAH.

Pharmacology of a Potent and Novel Inhibitor of the NOD-Like Receptor Pyrin Domain-Containing Protein 3 (NLRP3) Inflammasome that Attenuates Development of Nonalcoholic Steatohepatitis and Liver Fibrosis.

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome is a multiprotein complex and component of the innate immune system that is activated by exogenous and endogenous danger signals to promote activation of caspase-1 and the maturation and release of the proinflammatory cytokines interleukin (IL)-1β and IL-18. Inappropriate activation of NLRP3 has been implicated in the pathophysiology of multiple inflammatory and autoimmune diseases, including cardiovascular disease, neurodegenerative diseases, and nonalcoholic steatohepatitis (NASH), thus increasing the clinical interest of this target. We describe in this study the preclinical pharmacologic, pharmacokinetic, and pharmacodynamic properties of a novel and highly specific NLRP3 inhibitor, JT001 (6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine-3-sulfonylurea). In cell-based assays, JT001 potently and selectively inhibited NLRP3 inflammasome assembly, resulting in the inhibition of cytokine release and the prevention of pyroptosis, a form of inflammatory cell death triggered by active caspase-1. Oral administration of JT001 to mice inhibited IL-1β production in peritoneal lavage fluid at plasma concentrations that correlated with mouse in vitro whole blood potency. Orally administered JT001 was effective in reducing hepatic inflammation in three different murine models, including the Nlrp3A350V /+CreT model of Muckle-Wells syndrome (MWS), a diet-induced obesity NASH model, and a choline-deficient diet-induced NASH model. Significant reductions in hepatic fibrosis and cell damage were also observed in the MWS and choline-deficient models. Our findings demonstrate that blockade of NLRP3 attenuates hepatic inflammation and fibrosis and support the use of JT001 to investigate the role of NLRP3 in other inflammatory disease models. SIGNIFICANCE STATEMENT: Persistent inflammasome activation is the consequence of inherited mutations of NLRP3 and results in the development of cryopyrin-associated periodic syndromes associated with severe systemic inflammation. NLRP3 is also upregulated in nonalcoholic steatohepatitis, a metabolic chronic liver disease currently missing a cure. Selective and potent inhibitors of NLRP3 hold great promise and have the potential to overcome an urgent unmet need.

Gentiopicroside enhances the protective effect of trimetazidine against myocardial ischemia-reperfusion injury via the AMPK/NLRP3 inflammasome signaling.

Myocardial ischemia-reperfusion injury (MI/R) leads to the inevitable clinical consequences of myocardial infarction and subsequent heart failure. Trimetazidine (TMZ), an anti-ischemic agent, exerts protective potential in MI/R but had limited efficacy for some patients. Here we sought to investigate the single and combined application of gentiopicroside (GPS) and TMZ in MI/R. Notably, GPS had little cytotoxicity to cardiomyocytes. GPS attenuated hypoxia/reoxygenation (H/R)-induced cell death, reactive oxygen species production, lactate dehydrogenase and malondialdehyde releases, and antioxidant stress enzyme superoxide dismutase activity, indicating the protective efficacy of GPS against H/R-induced oxidative injury. Importantly, GPS enhanced the protective efficacy of TMZ against H/R-mediated cardiomyocyte injury. Additionally, GPS mitigated the transcription and releases of pro-inflammatory cytokine interleukin-6 and tumor necrosis factor-α in H/R-treated cardiomyocytes, which were enhanced after co-treatment with TMZ. Mechanistically, GPS activated the AMP-activated protein kinase (AMPK) signaling to inhibit H/R-induced NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome, which was further enhanced after costimulation with TMZ. Importantly, blocking the AMPK signaling reversed the protective roles of GPS and its combination with TMZ in H/R-induced oxidative insult and inflammation. In vivo, both GPS and TMZ alleviated the abnormal cardiac structure, cardiomyocyte apoptosis, and cardiac dysfunction in MI/R rats, which were further enhanced after administration with GPS and TMZ together. Furthermore, GPS intensified TMZ-mediated inhibition of oxidative injury, inflammation, and the AMPK/NLRP3 signaling in MI/R rats. Collectively, GPS enhances the protective efficacy of TMZ against MI/R injury through AMPK activation-mediated inhibition of NLRP3 inflammasome signaling, implying a promising therapeutic agent for the treatment of MI/R.

AMPK activation attenuates cancer-induced bone pain by reducing mitochondrial dysfunction-mediated neuroinflammation.

Bone metastasis of cancer cells leads to severe pain by disrupting bone structure and inducing central sensitization. Neuroinflammation in the spinal cord plays a decisive role in the maintenance and development of pain. In the current study, male Sprague-Dawley (SD) rats are used to establish a cancer-induced bone pain (CIBP) model by intratibial injection of MRMT-1 rat breast carcinoma cells. Morphological and behavioral analyses verify the establishment of the CIBP model, which represents bone destruction, spontaneous pain and mechanical hyperalgesia in CIBP rats. Activation of astrocytes marked by upregulated glial fibrillary acidic protein (GFAP) and enhanced production of the proinflammatory cytokine interleukin-1β (IL-1β) are accompanied by increased inflammatory infiltration in the spinal cord of CIBP rats. Furthermore, activation of the NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome is consistent with increased neuroinflammation. Adenosine monophosphate-activated protein kinase (AMPK) activation is involved in attenuating inflammatory pain and neuropathic pain. Intrathecal injection of the AMPK activator AICAR in the lumbar spinal cord reduces dynamin-related protein 1 (Drp1) GTPase activity and suppresses NLRP3 inflammasome activation. This effect consequently alleviates pain behaviors in CIBP rats. Cell research on C6 rat glioma cells indicates that AICAR treatment restores IL-1β-induced impairment of mitochondrial membrane potential and elevation of mitochondrial reactive oxygen species (ROS). In summary, our findings indicate that AMPK activation attenuates cancer-induced bone pain by reducing mitochondrial dysfunction-mediated neuroinflammation in the spinal cord.

PHLDA1 modulates microglial response and NLRP3 inflammasome signaling following experimental subarachnoid hemorrhage.

Balancing microglia M1/M2 polarization is an effective therapeutic strategy for neuroinflammation after subarachnoid hemorrhage (SAH). Pleckstrin homology-like domain family A member 1 (PHLDA1) has been demonstrated to play a crucial role in immune response. However, the function roles of PHLDA1 in neuroinflammation and microglial polarization after SAH remain unclear. In this study, SAH mouse models were assigned to treat with scramble or PHLDA1 small interfering RNAs (siRNAs). We observed that PHLDA1 was significantly increased and mainly distributed in microglia after SAH. Concomitant with PHLDA1 activation, nod-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome expression in microglia was also evidently enhanced after SAH. In addition, PHLDA1 siRNA treatment significantly reduced microglia-mediated neuroinflammation by inhibiting M1 microglia and promoting M2 microglia polarization. Meanwhile, PHLDA1 deficiency reduced neuronal apoptosis and improved neurological outcomes after SAH. Further investigation revealed that PHLDA1 blockade suppressed the NLRP3 inflammasome signaling after SAH. In contrast, NLRP3 inflammasome activator nigericin abated the beneficial effects of PHLDA1 deficiency against SAH by promoting microglial polarization to M1 phenotype. In all, we proposed that PHLDA1 blockade might ameliorate SAH-induced brain injury by balancing microglia M1/M2 polarization via suppression of NLRP3 inflammasome signaling. Targeting PHLDA1 might be a feasible strategy for treating SAH.

Peimine Inhibits MCF-7 Breast Cancer Cell Growth by Modulating Inflammasome Activation: Critical Roles of MAPK and NF-κB Signaling.

Peimine (PM) is a bioactive compound obtained from Fritillaria. It has been documented that PM exhibits potent antitumor properties against multiple cancers. However, the antitumor properties of PM in breast cancer and its associated mechanisms have not been clarified. Proliferation and apoptosis of MCF-7 and MCF-10A cells were detected by CCK8, colony formation, and flow cytometry assays. Cytotoxicity was measured by Lactate dehydrogenase (LDH) leakage assay. The level of IL-1β and IL-18 were detected with ELISA kits. Western blotting and real-time Polymerase Chain Reaction were performed to analyze the expression of proteins and genes related to the NLRP3 inflammasome pathway and Endoplasmic reticulum stress. The doses of PM (5, 10, and 20 μM) inhibited cell viability significantly, apoptotic induction, and inflammasome activation in breast cancer cells in vitro. Inflammasome components were decreased, including the apoptosisassociated speck like protein containing a CARD (ASC) and NOD-like receptor pyrindomain-containing protein3 (NLRP3), as well as the inhibition of caspase-1 and interleukin-1β activation. Moreover, inflammasome inhibitors suppressed cell growth and induced apoptosis, implying that PM suppresses the growth of breast cancer cells through regulating inflammasome. Mechanistically, PM inhibited the activity of inflammasome by alleviating endoplasmic reticulum (ER) stress and by down-regulating the expression of multiple proteins in transcription factor nuclear factor- κB (NF-κB) and mitogen-activated protein kinases (MAPKs) signaling pathways. These findings show that PM suppresses the growth of breast cancer cells by inhibiting inflammasome activation, to a certain extent, by primarily acting on the MAPK/NF-κB pathway's inactivation-dependent mechanisms.

Abstract 11665: Mediation of Sterile Inflammation Through Ca 2+ / Calmodulin-Dependent Protein Kinase in Macrophage is Essential for Pressure Overload-Induced Adverse Cardiac Remodeling

Introduction: There is evidence that inflammation is associated with pressure overload induced cardiac remodeling and heart failure, as well as evidence for a role of Ca 2+ / Calmodulin-dependent protein kinase II (CaMKII) in remodeling and heart failure development. Pressure overload triggers inflammatory gene expression and the activation of the NOD-like receptor pyrin domain containing protein 3 (NLRP3) inflammasome in cardiomyocytes. These responses provide signals for macrophage recruitment, fibrosis, and myocardial dysfunction in the heart. However, the downstream mechanism is not elucidated. Methods and Results: Macrophage specific CaMKIIdelta knockout (mKO) mice were subjected to transverse aortic constriction (TAC). Cardiomyocyte mRNA levels for pro-inflammatory chemokines and cytokines increased and peaked with 5 to 10 folds vs sham in both control and mKO mice. Priming and activation of the NLRP3 inflammasome, assessed by measuring NLRP3 mRNA and caspase-1 activity, were increased by TAC in isolated cardiomyocytes of both control and mKO. In contrast, caspase-1 activation in isolated macrophage were attenuated in mKO. CD68 positive cell accumulation and cardiac fibrosis in cardiac tissue in response to pressure overload were also attenuated in mKO vs control (CD68 41 ± 9 cells/mm 2 vs 78 ± 13 cells/mm 2 , fibrotic area 8.5 ± 1.2 % vs 4.1 ± 0.9 %). Subsequent cardiac dysfunction in response to pressure overload were less impaired in the mKO vs control (ejection fraction 44 ± 3% vs 35 ± 6%). Conclusions: Activated CaMKIIdelta in response to pressure overload triggers inflammatory signals including NLRP3 inflammasome cascade in cardiomyocytes. It also contributes amplification of inflammasome signal in macrophages leading fibrosis and consequent cardiac dysfunction. CaMKIIdelta in cardiomyocytes and macrophages could be a therapeutic anti-inflammatory and anti-fibrotic target for preventing adverse cardiac remodeling and heart failure.

The selective NLRP3 inflammasome inhibitor MCC950 improves isoproterenol-induced cardiac dysfunction by inhibiting cardiomyocyte senescence

BackgroundActivation of the NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome contributes to heart failure (HF) pathogenesis. However, the effect of NLRP3 inhibition on β-adrenergic receptor agonist-induced HF remains unknown. Here, we evaluated the role of MCC950, a selective NLRP3 inhibitor, in isoproterenol (ISO)-induced cardiac dysfunction. MethodsMice were administered ISO (30 mg/kg/day) for 14 days with or without MCC950 (10 mg/kg) injection every other day. Cardiac function and the extent of hypertrophy and fibrosis were measured by echocardiography, HE and Masson trichrome staining, respectively. Immunohistochemistry, quantitative real-time PCR and Western blotting were performed to investigate the impact of MCC950 on ISO-induced cardiac dysfunction. The levels of oxidative stress and cell senescence were detected in H9C2 cells to explore the mechanism of MCC950 on ISO-induced myocardial injury in vitro. ResultsWe found that the NLRP3 inflammasome was significantly activated in response to ISO treatment in mice. Selective inhibition of the NLRP3 inflammasome by MCC950 ameliorated cardiac fibrosis, hypertrophy and inflammation in ISO-treated mice, ultimately improving heart function. Furthermore, MCC950 significantly inhibited ISO-induced oxidative stress in the myocardium, accompanied by increased superoxide dismutase 2 (SOD2) and nuclear factor erythroid 2-related factor 2 (Nrf2) protein. In addition, MCC950 attenuated cardiomyocyte death and senescence in ISO-treated H9C2 cells, which was attributed to the decreased oxidative stress. ConclusionNLRP3 inhibition by MCC950 ameliorated ISO-induced cardiac dysfunction by inhibiting cardiomyocyte senescence and oxidative stress. Therefore, inhibition of the NLRP3 inflammasome may be a potential therapeutic strategy for preventing cardiac dysfunction, especially age-related HF.

Theacrine alleviates sepsis-induced acute kidney injury by repressing the activation of NLRP3/Caspase-1 inflammasome.

Acute kidney injury (AKI) is a frequent and serious complication of sepsis, which results in a rapid decline of kidney function. Currently, there are no curative therapies for AKI. Theacrine is a purine alkaloid and exerts significant role in regulating inflammation, oxidative stress, and mood elevation. The study aims to evaluate the biological role and potential mechanism of theacrine in septic AKI. The murine and cellular models of septic AKI were established in lipopolysaccharide (LPS)-treated C57BL/6 mice and HK-2 cells, respectively. The effect of theacrine on alleviating septic AKI was assessed after pretreatment with theacrine in vivo and in vitro. We found that theacrine treatment significantly alleviated LPS-induced kidney injury, as evidenced by decreased levels of kidney injury markers (blood urea nitrogen and creatinine), inflammatory factors (IL-1β and IL-18), and cell apoptosis in vivo and in vitro. Mechanistically, theacrine markedly repressed the activation of NOD-like receptor (NLR) pyrin domain-containing protein 3 (NLRP3)inflammasome. As expected, MCC950 (a specific inhibitor of NLRP3) treatment also decreased LPS-induced production of IL-18 and IL-1β and cell apoptosis in HK-2 cells. More important, Nigericin sodiumsalt (a NLRP3 agonist) damaged the effect of theacrine on repressing kidney injury markers (blood urea nitrogen and creatinine), pro-inflammatory cytokines (IL-18 and IL-1β), and cell apoptosis. Taken together, these results demonstrate that theacrine alleviates septic AKI, at least in part by repressing the activation of NLRP3 inflammasome.

N-3 polyunsaturated fatty acids protect esophageal epithelial cells from acid exposure

Our previous study showed that n-3 PUFAs inhibited inflammation in rats with esophagitis. This study aimed to observe the protective effect of n-3 PUFAs against acid damage to esophageal epithelial cells (Het-1A cells) and to explore its mechanism. The level of malondialdehyde (MDA) was increased by acid exposure, while that of superoxide dismutase (SOD) was decreased. In groups with different ratios of n-6/n-3 PUFAs, the expression levels of nuclear factor E2 related factor 2 (Nrf2) and SOD were increased with increasing proportions of n-3 PUFAs and were highest in the 1:1 group. Compared with those in the 9:1 group, the expression of NOD like receptor pyrin domain-containing protein 3 (NLRP3) and caspase-1 and the pyroptosis rate in the 1:1 group were decreased. Intervention with an Nrf2 agonist increased the expression of Nrf2 and decreased the expression of NLRP3 and caspase-1 and the pyroptosis rate. However, inhibiting Nrf2 expression led to the opposite result. In conclusion, n-3 PUFAs protected esophageal epithelial cells from acid damage by upregulating Nrf2 expression, which disrupted oxidative stress and NLRP3 inflammasome activation and inhibited pyroptosis.

Increased NLRP3 inflammasome expression in peripheral blood mononuclear cells of patients with schizophrenia: a case-control study

Objective This study aimed to evaluate the gene expression of the P2X purinoceptor 7 (P2X7R)- nod-like receptor pyrin domain-containing protein 3 (NLRP3) signal pathway in peripheral blood mononuclear cells (PBMCs) between schizophrenia (SCZ) patients and healthy controls (HC) to reveal its relationship with clinical variables. Methods Thirty-two SCZ patients and 41 healthy controls were included in this study. The Scale for the Assessment of Positive Symptoms (SAPS) and the Scale for the Assessment of Negative Symptoms (SANS), The Global Assessment of Functioning (GAF) scale and the Functioning Assessment Short Test (FAST) scales were applied. P2X7R, NLRP3, IL-1β and IL-18 gene expression levels were evaluated by real-time polymerase chain reaction in PBMCs. Results NLRP3, P2RX7, IL-1β and IL-18 expression levels were significantly higher in PBMCs of SCZ patients than in HC subjects. Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores. There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores and a positive correlation with the SAPS scale scores. Conclusions Systemic inflammation is implicated in SCZ pathogenesis, according to our findings, which suggest that the NLRP3 pathway may be involved. The NLRP3 inflammasome may serve as a biomarker for SCZ, and its pharmacological regulation may be a promising treatment approach. Key points We hypothesised that the NLRP3 pathway may contribute to the etiopathogenesis of schizophrenia. NLRP3, IL-1β and IL-18 mRNA levels were higher in patients with schizophrenia compared to healthy controls. Negative correlations were found between NLRP3 gene expression levels and GAF and FAST scales scores. There was a negative correlation between IL-18 expression levels and the GAF and FAST scales scores. The SAPS scale scores and IL-18 expression levels had a positive correlation. Given all these findings, it can be stated that NLRP3 inflammasome may play a role in the pathogenesis and symptoms of schizophrenia.

GPR40 agonist inhibits NLRP3 inflammasome activation via modulation of nuclear factor-κB and sarco/endoplasmic reticulum Ca2+-ATPase

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome is a multi-protein intracellular complex that activates proinflammatory cytokines, including interleukin (IL)-1β and IL-18. Inflammasome activation is related to metabolic inflammation, such as the progression of non-alcoholic steatohepatitis. Fasiglifam (TAK875), a selective G-protein coupled receptor 40 (GPR40) agonist with high affinity, significantly improves glucose-dependent insulin secretion and weight gain without hypoglycemia. Interestingly, we found that two GPR40 agonists, TAK875 and AMG1638, suppressed activation of the NLRP3 inflammasome in bone marrow-derived macrophages (BMDMs). TAK875 inhibited inflammasome activation by blocking formation of apoptosis-associated speck-like protein containing a CARD (ASC), an inflammasome component. TAK875 also suppressed NLRP3 inflammasome-induced pyroptosis of BMDMs. Moreover, nuclear factor-kappa B (NF-κB)-dependent priming of the NLRP3 inflammasome was partially inhibited by TAK875 and AMG1638. The intracellular Ca2+ increase caused by ATP, nigericin (pore-forming toxin), or endoplasmic reticulum stress activates the NLRP3 inflammasome. Pre-exposure of BMDMs to TAK875 suppressed the ATP-induced intracellular Ca2+ increase, which was reversed by thapsigargin, a sarco/endoplasmic reticulum Ca2+-ATPase inhibitor. Oral administration of mice with TAK875 suppressed the increase in serum IL-1β in mice treated with lipopolysaccharide/D-galactosamine in vivo. These findings indicate that the free fatty acid-sensing GPR40 plays a key role in the NLRP3 inflammasome pathway.

Betulin alleviates cisplatin-induced hepatic injury in rats: Targeting apoptosis and Nek7-independent NLRP3 inflammasome pathways

Cisplatin is a chemotherapeutic agent that induces multiorgan toxicity side effect due to induction of inflammation, apoptosis and disruption of intracellular antioxidant pathways. Betulin is a natural triterpenoid that has been shown to counteract cisplatin-induced nephrotoxicity. In this study, we investigated the ameliorative effect of betulin against cisplatin-promoted hepatotoxicity in rats. Moreover, we studied the molecular mechanism underlying betulin’s effect. Single intraperitoneal injection (i.p.) of 10 mg/kg of cisplatin, was used to induce acute liver injury in rats. To assess betulin effect, a dose of 8 mg/kg (i.p.) was daily administered for 10 days. Betulin significantly improved serum Aspartate transaminase (AST), Alanine transaminase (ALT), albumin and total bilirubin levels in comparison with cisplatin group. Histopathologically, betulin restored cisplatin-deteriorated liver structural features and hepatic fibrosis. Mechanistically, betulin reduced hepatic oxidative stress as indicated by increased total antioxidant capacity and decreased malondialdehyde levels compared to cisplatin group. In addition, betulin reduced hepatic inflammation via significant inhibition of NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome, caspase-1 and interleukin-1β (IL-1β) levels. Intriguingly, betulin did not affect the expression levels of the mitotic kinase NIMA-related kinase 7 (Nek7), an NLRP3 interacting/activating protein. Last, Betulin induced anti-apoptotic effects as denoted by significant downregulation of P53 and Bax apoptotic proteins, upregulation of the anti-apoptotic protein, BCL2 and reduction of caspases 8, −9 and −3. This study is the first to provide evidence that betulin might be beneficial as a safe therapeutic approach to manage cisplatin-induced hepatotoxicity via targeting inflammatory and apoptotic pathways.

Hepatoprotective effect of Betulin against Cisplatin‐induced toxicity via inhibiting apoptotic and Nek7‐independent NLRP3 inflammasome pathways: An in vivo study

Background Despite its wide use, cisplatin induces serious multiorgan toxicity via stimulating vicious inflammatory, oxidative stress and apoptotic cascades. Betulin is a naturally occurring triterpene that has been shown to protect against cisplatin-induced nephrotoxicity, yet its protective effect against cisplatin-induced hepato- and cardiotoxicity has not been studied. Aim of the work Here we investigated the potential protective effect of betulin against cisplatin-induced hepatotoxicity in rats and the potential underlying mechanism of this effect. Methods Induction of cisplatin acute hepatotoxicity was achieved by single intraperitoneal injection of 10 mg/kg in the middle of the experimental model timeframe. Betulin treatment (8 mg/kg) was intraperitoneally injected daily for total period of 10 days. Results Treatment with betulin significantly improved biochemical liver functions as indicated by restoring cisplatin disrupted levels of serum Aspartate transaminase (AST), Alanine transaminase (ALT), albumin and total bilirubin. In addition, betulin significantly improved histopathological structural features of liver tissues and significantly reduced hepatic tissue fibrosis turnover. Betulin hepatoprotective effect was mediated via reducing cisplatin-provoked oxidative stress, inflammation and apoptosis. Specifically, betulin increased hepatic total antioxidant capacity and decreased hepatic malondialdehyde levels compared to cisplatin group. In addition, betulin significantly attenuated cisplatin-induced NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome pathway activation as evident by downregulating hepatic tissue levels of NLRP3, caspase-1 and interleukin-1β (IL-1β). Interestingly, despite of the cisplatin-induced upregulation of the hepatic NLRP3 interacting protein, mitotic kinase NIMA-related kinase 7 (Nek7), betulin did not induce any significant alteration of its levels in liver tissues. Betulin significantly reduced cisplatin-induced apoptosis induction as indicated by significant reduction of the apoptotic proteins P53 and Bax, significant reduction of caspases-8, -9 and -3 and upregulation of the anti-apoptotic protein Bcl2. Conclusion To the best of our knowledge, this is the first study to address the hepatoprotective effect of betulin against cisplatin-induced liver injury through modulation of inflammatory and apoptotic pathways.