Role of NOD-like receptor protein 3 inflammasome in the development and progression of hepatocellular carcinoma / 临床肝胆病杂志

In recent years， NOD-like receptor protein 3 （NLRP3） inflammasome in tumors has become a research hotspot， especially in melanoma， colorectal cancer， lung cancer， and breast cancer， and more and more evidence has shown that inflammation plays a role in the development， progression， angiogenesis， and invasion of cancer. Hepatocellular carcinoma （HCC） is the most common type of primary liver cancer， and there are still controversies over the role of NLRP3 inflammasome in the development and progression of HCC. Therefore， this article reviews the potential impact of NLRP3 inflammasome in the progression of HCC and its mechanism of action in anticancer therapy， and it is believed that NLRP3 inflammasome can be used as an effective therapeutic target for HCC patients.

NLRP3 Exacerbate NETosis-Associated Neuroinflammation in an LPS-Induced Inflamed Brain.

Neutrophil extracellular traps (NETs) exert a novel function of trapping pathogens. Released NETs can accumulate in inflamed tissues, be recognized by other immune cells for clearance, and lead to tissue toxicity. Therefore, the deleterious effect of NET is an etiological factor, causing several diseases directly or indirectly. NLR family pyrin domain containing 3 (NLRP3) in neutrophils is pivotal in signaling the innate immune response and is associated with several NET-related diseases. Despite these observations, the role of NLRP3 in NET formation in neuroinflammation remains elusive. Therefore, we aimed to explore NET formation promoted by NLRP3 in an LPS-induced inflamed brain. Wild-type and NLRP3 knockout mice were used to investigate the role of NLRP3 in NET formation. Brain inflammation was systemically induced by administering LPS. In such an environment, the NET formation was evaluated based on the expression of its characteristic indicators. DNA leakage and NET formation were analyzed in both mice through Western blot, flow cytometry, and in vitro live cell imaging as well as two-photon imaging. Our data revealed that NLRP3 promotes DNA leakage and facilitates NET formation accompanied by neutrophil death. Moreover, NLRP3 is not involved in neutrophil infiltration but is predisposed to boost NET formation, which is accompanied by neutrophil death in the LPS-induced inflamed brain. Furthermore, either NLRP3 deficiency or neutrophil depletion diminished pro-inflammatory cytokine, IL-1ß, and alleviated blood-brain barrier damage. Overall, the results suggest that NLRP3 exacerbates NETosis in vitro and in the inflamed brain, aggravating neuroinflammation. These findings provide a clue that NLRP3 would be a potential therapeutic target to alleviate neuroinflammation.

Extracellular Acidification Augments NLRP3-Mediated Inflammasome Signaling in Macrophages.

Inflammation is a series of host defense processes in response to microbial infection and tissue injury. Inflammatory processes frequently cause extracellular acidification in the inflamed region through increased glycolysis and lactate secretion. Therefore, the immune cells infiltrating the inflamed region encounter an acidic microenvironment. Extracellular acidosis can modulate the innate immune response of macrophages; however, its role for inflammasome signaling still remains elusive. In the present study, we demonstrated that macrophages exposed to an acidic microenvironment exhibited enhanced caspase-1 processing and IL-1ß secretion compared with those under physiological pH. Moreover, exposure to an acidic pH increased the ability of macrophages to assemble the NLR family pyrin domain containing 3 (NLRP3) inflammasome in response to an NLRP3 agonist. This acidosis-mediated augmentation of NLRP3 inflammasome activation occurred in bone marrow-derived macrophages but not in bone marrow-derived neutrophils. Notably, exposure to an acidic environment caused a reduction in the intracellular pH of macrophages but not neutrophils. Concordantly, macrophages, but not neutrophils, exhibited NLRP3 agonist-mediated translocation of chloride intracellular channel protein 1 (CLIC1) into their plasma membranes under an acidic microenvironment. Collectively, our results demonstrate that extracellular acidosis during inflammation can increase the sensitivity of NLRP3 inflammasome formation and activation in a CLIC1-dependent manner. Thus, CLIC1 may be a potential therapeutic target for NLRP3 inflammasome-mediated pathological conditions.

Effect and mechanism of reactive oxygen species-mediated NOD-like receptor family pyrin domain-containing 3 inflammasome activation in hepatic alveolar echinococcosis.

BACKGROUND: The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is a significant component of the innate immune system that plays a vital role in the development of various parasitic diseases. However, its role in hepatic alveolar echinococcosis (HAE) remains unclear. AIM: To investigate the NLRP3 inflammasome and its mechanism of activation in HAE. METHODS: We assessed the expression of NLRP3, caspase-1, interleukin (IL)-1ß, and IL-18 in the marginal zone and corresponding normal liver of 60 patients with HAE. A rat model of HAE was employed to investigate the role of the NLRP3 inflammasome in the marginal zone of HAE. Transwell experiments were conducted to investigate the effect of Echinococcus multilocularis (E. multilocularis) in stimulating Kupffer cells and hepatocytes. Furthermore, immunohistochemistry, Western blotting, and enzyme-linked immunosorbent assay were used to evaluate NLRP3, caspase-1, IL-1ß, and IL-18 expression; flow cytometry was used to detect apoptosis and reactive oxygen species (ROS). RESULTS: NLRP3 inflammasome activation was significantly associated with ROS. Inhibition of ROS production decreased NLRP3-caspase-1-IL-1ß pathway activation and mitigated hepatocyte damage and inflammation. CONCLUSION: E. multilocularis induces hepatocyte damage and inflammation by activating the ROS-mediated NLRP3-caspase-1-IL-1ß pathway in Kupffer cells, indicating that ROS may serve as a potential target for the treatment of HAE.

Astragaloside IV plays a role in reducing radiation-induced liver inflammation in mice by inhibiting thioredoxin-interacting protein/nod-like receptor protein 3 signaling pathway.

OBJECTIVE: To investigate the efficacy of Astragaloside IV (AS-IV) on radiation-induced liver inflammation in mice. METHODS: The mice were divided into normal group, dimethyl sulfoxide solvent group, irradiation group (IR), irradiation + AS-IV (20 mg/kg) group (IR+AS-20) and irradiation + AS-IV (40 mg/kg) group (IR+AS-40). One month after intraperitoneal injection of AS-IV, the mice were irradiated with 8Gry Co60γ, the blood was collected for biochemical analysis, and the liver was collected for hematoxylin-eosin staining, immunofluorescence and electron microscopic observation, oxidative stress, and Western blot analysis. RESULTS: The AS-IV treatment significantly ameliorated the pathological morphology of liver and reduced the alanine aminotransferase and aspertate amino-transferase levels in serum induced by radiation; AS-IV treatment also significantly reduced the expression of inflammatory factors tumor necrosis factor alpha and interleukin 6 and antagonized malonaldehyde content and superoxide dismutase activity in liver caused by radiation; in addition, AS-IV treatment can significantly inhibited the positive expression of thioredoxin-interacting protein (TXNIP) and nod-like receptor protein 3 (NLRP3) inflammasome in liver tissue after radiation; The expression of TXNIP, NLRP3 inflammasome, apoptosis-associated speck-like protein containing a CARD, cysteinyl aspartate-specific proteinase 1 and interleukin 1beta in the AS-IV prevention group decreased significantly compared to the radiation group. CONCLUSIONS: These findings suggested that Co60γ radiation can cause structural and functional damage to the liver, which may be related to the NLRP3 mediated inflammatory pathway; AS-IV may play a protective role by inhibiting the TXNIP/NLRP3 inflammasome signaling pathway in the radiation-induced liver injury model.

NLRP3 Inflammasome Activation Through Heart-Brain Interaction Initiates Cardiac Inflammation and Hypertrophy During Pressure Overload.

BACKGROUND: Mechanical stress on the heart, such as high blood pressure, initiates inflammation and causes hypertrophic heart disease. However, the regulatory mechanism of inflammation and its role in the stressed heart remain unclear. IL-1ß (interleukin-1ß) is a proinflammatory cytokine that causes cardiac hypertrophy and heart failure. Here, we show that neural signals activate the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3) inflammasome for IL-1ß production to induce adaptive hypertrophy in the stressed heart. METHODS: C57BL/6 mice, knockout mouse strains for NLRP3 and P2RX7 (P2X purinoceptor 7), and adrenergic neuron-specific knockout mice for SLC17A9, a secretory vesicle protein responsible for the storage and release of ATP, were used for analysis. Pressure overload was induced by transverse aortic constriction. Various animal models were used, including pharmacological treatment with apyrase, lipopolysaccharide, 2'(3')-O-(4-benzoylbenzoyl)-ATP, MCC950, anti-IL-1ß antibodies, clonidine, pseudoephedrine, isoproterenol, and bisoprolol, left stellate ganglionectomy, and ablation of cardiac afferent nerves with capsaicin. Cardiac function and morphology, gene expression, myocardial IL-1ß and caspase-1 activity, and extracellular ATP level were assessed. In vitro experiments were performed using primary cardiomyocytes and fibroblasts from rat neonates and human microvascular endothelial cell line. Cell surface area and proliferation were assessed. RESULTS: Genetic disruption of NLRP3 resulted in significant loss of IL-1ß production, cardiac hypertrophy, and contractile function during pressure overload. A bone marrow transplantation experiment revealed an essential role of NLRP3 in cardiac nonimmune cells in myocardial IL-1ß production and cardiac phenotype. Pharmacological depletion of extracellular ATP or genetic disruption of the P2X7 receptor suppressed myocardial NLRP3 inflammasome activity during pressure overload, indicating an important role of ATP/P2X7 axis in cardiac inflammation and hypertrophy. Extracellular ATP induced hypertrophic changes of cardiac cells in an NLRP3- and IL-1ß-dependent manner in vitro. Manipulation of the sympathetic nervous system suggested sympathetic efferent nerves as the main source of extracellular ATP. Depletion of ATP release from sympathetic efferent nerves, ablation of cardiac afferent nerves, or a lipophilic ß-blocker reduced cardiac extracellular ATP level, and inhibited NLRP3 inflammasome activation, IL-1ß production, and adaptive cardiac hypertrophy during pressure overload. CONCLUSIONS: Cardiac inflammation and hypertrophy are regulated by heart-brain interaction. Controlling neural signals might be important for the treatment of hypertensive heart disease.

Puerarin protects renal ischemia-reperfusion injury in rats through NLRP3/Caspase-1/GSDMD pathway

Purpose: To observe the effect of puerarin on renal ischemia-reperfusion (I/R) injury in rats, and to explore its mechanism based on NLRP3/Caspase-1/GSDMD pathway. Methods: Twenty-one Sprague-Dawley rats were divided into three groups: sham-operated group (sham), model group (RIRI), and puerarin treatment group (RIRI + Pue). The model of acute renal I/R injury was established by cutting the right kidney and clamping the left renal pedicle for 45 min. Results: Renal function parameters were statistically significant in group comparisons. The renal tissue structure of rats in sham group was basically normal. Pathological changes were observed in the RIRI group. The renal pathological damage score and apoptosis rate in the RIRI group were higher than those in the sham group, and significantly lower in the RIRI + Pue group than in the RIRI group. Indicators of oxidative stress-superoxide dismutase, malondialdehyde, and glutathione peroxidase-were statistically significant in group comparisons. Compared with the sham group, the relative expressions of NLRP3, Caspase-1 and GSDMD proteins in the RIRI group were increased. Compared with the RIRI group, the RIRI + Pue group had significant reductions. Conclusions: Puerarin can inhibit the activation of NLRP3/Caspase-1/GSDMD pathway, inhibit inflammatory response and pyroptosis, and enhance the antioxidant capacity of kidney, thereby protecting renal I/R injury in rats.

Metabolic regulation of Nod-like receptor protein 3 inflammasome and its role in renal diseases / 中华肾脏病杂志

In recent years, with the development of metabolic reprogramming research, people have changed their understanding of the biological effects of immune cells. Under the stimulation of inflammatory response, immune cells re-regulate their metabolism and bioenergetics, provide energy and substrates for cell survival, and initiate immune effect functions. Nod-like receptor protein 3 (NLRP3) inflammasome, as an important component of the innate immune system, has been shown to sense metabolites such as uric acid and cholesterol crystals, and can be inhibited by metabolites such as ketones. It is also regulated by mitochondrial reactive oxygen species and glycolytic components (such as hexokinase). Recent studies have shown that a variety of metabolic pathways converge as effective regulators of NLRP3 inflammasome. The paper reviews the metabolic regulatory pathways and specificity of NLRP3 inflammasome activation, and its role in renal diseases.

Hepatitis B virus X protein promotes podocyte pyroptosis in hepatitis B virus-associated glomerulonephritis by down-regulating microRNA -223 targeting NLRP3 inflammasome / 中华肾脏病杂志

Objective:To investigate the potential function and related mechanism of microRNA-223 (miRNA-223) in the podocyte pyroptosis of hepatitis B virus (HBV)-associated glomerulonephritis induced by HBV X protein (HBx).Methods:HBx-overexpressing lentivirus was transfected into human renal podocytes to mimic the pathogenesis of HBV-GN. Real-time fluorescence quantitative PCR and Western blotting experiments were used to detect the mRNA and protein expression of pyroptosis-related proteins [nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD (ASC) and caspase-1], and inflammatory factors (interleukin-1β and interleukin-18), respectively.TUNEL staining and flow cytometry were used to detect the number of pyroptosis cells. Immunofluorescence staining was used to detect the expression of podocytes biomarkers desmin and nephrin; Hoechst 33342 staining was used to observe the morphological and quantitative changes of podocyte nuclei. Enzyme-linked immunosorbent assay was used to measure caspase-1 activity. The dual luciferase reporter gene assay was used to verify the downstream target of miRNA-223. Podocytes were divided into the following nine groups: control group (no special treatment), empty plasmid group (transfected with empty plasmid), HBx overexpression group (transfected with HBx overexpression lentivirus), HBx overexpression+miRNA-223 mimic group (transfected with HBx overexpression lentivirus and miRNA-223 mimic), HBx overexpression+miRNA-223 inhibitor group (transfected with HBx overexpression lentivirus and miRNA-223 inhibitor), HBx overexpression+miRNA-223 mimic+NLRP3 group (transfected with HBx overexpression lentivirus, miRNA-223 mimic and NLRP3 overexpression plasmid), HBx overexpression+miRNA-223 mimic+ NLRP3 siRNA group (transfected with HBx overexpression lentivirus, miRNA-223 mimic and NLRP3 siRNA), HBx overexpression+miRNA-223 inhibitor+NLRP3 group (transfected with HBx overexpression lentivirus, miRNA-223 inhibitor and NLRP3 overexpression plasmid), HBx overexpression+miRNA-223 inhibitor+NLRP3 siRNA group (transfected with HBx overexpression lentivirus, miRNA-223 inhibitor and NLRP3 siRNA).Results:miRNA-223 was down-regulated in HBx overexpression group compared with the control group ( P < 0.05). TUNEL and immunofluorescence staining showed that NLRP3 knockdown attenuated podocyte injury and pyroptosis induced by HBx overexpression ( P < 0.05). Dual luciferase reporter gene assay demonstrated that NLRP3 was one of the downstream targets of miRNA-223. Rescue experiments revealed that NLRP3 overexpression weakened the protective effect of miRNA-223 in podocyte injury ( P < 0.05). The addition of miRNA-223 mimic and NLRP3 siRNA decreased the expression of NLRP3 inflammasome and cytokines, and reduced the number of pyroptosis cells induced by HBx overexpression (all P < 0.05); The addition of miRNA-223 inhibitor and NLRP3 overexpression plasmid significantly increased the expression of NLRP3 inflammasome and cytokines, caspase-1 activity, and the number of pyroptosis cells (all P < 0.05). Conclusion:HBx may promote podocyte pyroptosis of HBV-GN via downregulating miRNA-223 targeting NLRP3 inflammasome, suggesting that miRNA-223 is expected to be a potential target for the treatment of HBV-GN.

Role of SIRT1/NLRP3 signaling pathway in sevoflurane postconditioning-induced attenuation of oxygen-glucose deprivation and restoration injury in HT22 cells / 中华麻醉学杂志

Objective:To evaluate the role of silent information regulator-1 (SIRT1)/nucleotide-binding domain (NOD)-like receptor protein-3 (NLRP3) signaling pathway in sevoflurane postconditioning-induced attenuation of oxygen-glucose deprivation and restoration (OGD/R) injury in mouse hippocampal neuronal cell line (HT22) cells.Methods:The HT22 cells were seeded in a culture plate (96-well plate, 100 μl/well; 6-well plate, 2 ml/well) at the density of 5×10 4 cells/ml or in a culture dish (6 cm in diameter) and then divided into 4 groups ( n=24 each) using a random number table method: control group (Control group), OGD/R group, sevoflurane postconditioning group (SPC group), and SIRT1 small interfering RNA group (si-SIRT 1 group). In Control group, cells were cultured at 37 ℃ in normal culture atmosphere. In OGD/R group, the culture medium was replaced with glucose-free serum-free culture medium, and cells were exposed to 95% N 2+ 5% CO 2 for 4 h in an incubator at 37 ℃, and then the glucose-free serum-free culture medium was replaced with the primary culture medium, and cells were cultured for 24 h at 37 ℃ in normal culture atmosphere. In SPC group, the glucose-free serum-free culture medium was replaced with the primary cell culture medium after 4-h oxygen and glucose deprivation, the cells were put into the hypoxia incubator chamber which was filled with 2% sevoflurane immediately after start of reoxygenation, then the chamber was placed in an incubator and the cells were cultured for 1 h at 37 ℃ in normal culture atmosphere, and finally the cells were removed from the chamber and cultured for 23 h at 37 ℃ in normal culture atmosphere. In si-SIRT1 group, SIRT1 small interfering RNA 150 pmol was added at 24 h before surgery, cells were then incubated, and the other procedures were the same as those previously described in group SPC. The cell survival rate was determined using MTT assay. TUNEL assay was used to detect cell apoptosis, and the apoptosis rate was calculated. The expression of SIRT1, NLRP3, IL-1β and IL-18 mRNA was determined using polymerase chain reaction. The expression of SIRT1, NLRP3, interleukin-1beta (IL-1β) and IL-18 was detected using Western blot. Results:Compared with Control group, the cell survival rate was significantly decreased, the apoptosis rate was increased, the expression of SIRT1 protein and mRNA was down-regulated, and the expression of NLRP3, IL-1β and IL-18 protein and mRNA was up-regulated in OGD/R group ( P<0.05). Compared with OGD/R group, the cell survival rate was significantly increased, the apoptosis rate was decreased, the expression of SIRT1 protein and mRNA was up-regulated, and the expression of NLRP3, IL-1β and IL-18 protein and mRNA was down-regulated in SPC group ( P<0.05). Compared with SPC group, the cell survival rate was significantly decreased, the apoptosis rate was increased, the expression of SIRT1 protein and mRNA was down-regulated, and the expression of NLRP3, IL-1β and IL-18 protein and mRNA was up-regulated in si-SIRT1 group ( P<0.05). Conclusions:Activation of SIRT1-NLRP3 signaling pathway is involved in sevoflurane postconditioning-induced attenuation of OGD/R injury in HT22 cells.

Role of bilateral superior cervical sympathetic ganglion in myocardial ischemia-reperfusion injury in mice: relationship with NLRP3 inflammasomes / 中华麻醉学杂志

Objective:To evaluate the role of bilateral superior cervical sympathetic ganglia (SCG) in myocardial ischemia-reperfusion (I/R) injury in mice and the relationship with NOD-like receptor protein 3 (NLRP3) inflammasomes.Methods:Thirty-two healthy SPF male C57BL mice, aged 8-10 weeks, weighing 25-30 g, were divided into 4 groups ( n=8 each) by the random number table method: sham operation group (NS group), myocardial I/R group (NIR group), bilateral SCG excision group (SCGx group) and bilateral SCG excision + myocardial I/R group (SCGx+ IR group). The myocardial I/R injury model was prepared by ligating the anterior descending branch of the left coronary artery for 30 min followed by 24 h reperfusion in isoflurane-anesthetized mice. Bilateral superior cervical sympathectomy was performed at 3 days before reperfusion. Blood samples were collected from the inferior vena cava at 24 h of reperfusion for examination of pathological changes (by HE and WGA staining) and for measurement of serum creatine kinase isoenzymes (CK-MB) activity, cardiac troponin I (cTnI) concentration, norepinephrine (NE) concentration and lactic dehydrogenase (LDH) activity (by enzyme-linked immunosorbent assay), superoxide dismutase (SOD) activity (by colorimetric method), myocardial reactive oxygen species (ROS) level (by DHE method), myocardial infarct size(by TTC method), and expression of interleukin-1beta (IL-1β), IL-6, IL-10, tumor necrosis factor-alpha (TNF-α), NLRP3 mRNA (by quantitativepolymerase chain reaction ), and expression of tyrosine hydroxylase (TH), IL-1β, TNF-α, NLRP3, atrial natriuretic peptide (ANP)and brain natriuretic peptide (BNP) (by Western blot). Results:Compared with NS group, the NE concentration was significantly decreased, and TH expression was down-regulated in SCGx group, and the serum CK-MB activity, concentrations of cTnI and NE, LDH activity and myocardial ROS level were significantly increased, SOD activity was decreased, the expression of IL-1β, TNF-α, NLRP3, ANP and BNP was up-regulated, and the expression of IL-1β, IL-6, TNF-α and NLPR3 mRNA was up-regulated in NIR group ( P<0.05). Compared with SCGx group, the serum CK-MB activity, concentrations of cTnI and NE, LDH activity and myocardial ROS levels were significamtly increased, SOD activity was decreased, the expression of IL-1β, TNF-α, NLRP3, ANP and BNP was up-regulated, and the expression of IL-1β, IL-6, TNF-α and NLPR3 mRNA was up-regulated in SCGx+ NIR group ( P<0.05). Compared with NIR group, the serum CK-MB activity, cTnI concentration, LDH activity and myocardial ROS level were significantly decreased, SOD activity was increased, the expression of IL-1β, TNF-α, NLRP3, ANP and BNP was down-regulated, the expression of IL-1β, IL-6, TNF-α and NLPR3 mRNA was down-regulated, and myocardial infarct size was decreased in SCGx+ NIR group ( P<0.05). Conclusions:The mechanism by which bilateral SCG excision attenuates myocardial I/R injury is associated with decreased NLRP3 inflammatory inflammasome activation and inhibition of inflammatory responses in mice.

Role of NLRP3 in sepsis-associated encephalopathy and the relationship with pyroptosis in microglia of mice / 中华麻醉学杂志

Objective:To evaluate the role of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) in sepsis-associated encephalopathy (SAE) and the relationship with pyroptosis in microglia of mice.Methods:Twenty-four SPF healthy male C57BL/6J mice, aged 6-8 weeks, weighing 18-22 g, were divided into 3 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SAE group and SAE plus an NLRP3 inhibitor MCC950 group (SAE+ MCC950 group). The mouse model of SAE was prepared by cecal ligation and puncture after anesthesia. MCC950 20 mg/kg was intraperitoneally injected at 1 h after developing the model in SAE+ MCC950 group, and the equal volume of normal saline was given instead in the other groups. Open field tests were conducted at 1 day after developing the model to record the number of rearing and time spent in the central area. Novel object recognition tests were conducted at 2-3 days after developing the model to record the recognition index. After the behavioral experiment on 3 day after developing the model, mice were sacrificed and hippocampal tissues were collected for determination of the expression of NLRP3 (by Western blot), count of cells co-expressing NLRP3 and microglia-specific ionized calcium-binding adaptor molecule 1 (Iba-1) (by immunofluorescence), activity of caspase-1, and contents of interleukin-1beta(IL-1β) and IL-18 (by enzyme-linked immunosorbent assay). Results:Compared with Sham group, the number of rearing was significantly reduced, the time spent in the central area was shortened, the recognition index was decreased, the expression of NLRP3 was up-regulated, the count of NLRP3 + -Iba-1 + cells was increased, and the activity of caspase-1 and contents of IL-1β and IL-18 were increased in SAE and SAE+ MCC950 groups ( P<0.05). Compared with SAE group, the number of rearing was significantly increased, the time spent in the central area was prolonged, the recognition index was increased, the expression of NLRP3 was down-regulated, the count of NLRP3 + -Iba-1 + cells was decreased, and the activity of caspase-1 and contents of IL-1β and IL-18 were decreased in SAE+ MCC950 group ( P<0.05). Conclusions:NLRP3 is involved in the development of SAE, which may be related to the mediation in microglial pyroptosis in mice.

Mechanism underlying reduction of cerebral ischemia-reperfusion injury by electroacupuncture preconditioning in rats: relationship between cannabinoid type 1 receptor and NLRP3 inflammasome / 中华麻醉学杂志

Objective:To evaluate the relationship between cannabinoid receptor 1 (CB1R) and the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) during the reduction of cerebral ischemia-reperfusion (I/R) injury by electroacupuncture (EA) preconditioning in rats.Methods:Forty SPF healthy male Sprague-Dawley rats, aged 7-9 weeks, weighing 250-280 g, were divided into 5 groups ( n=8 each) according to the random number table method: sham operation group (Sham group), cerebral I/R group (I/R group), EA preconditioning group (EA group), CB1R antagonist AM251+ EA preconditioning group (AM251+ EA group), and CB1R agonist WIN 55, 212-2 group (WIN group). Cerebral I/R was induced by middle cerebral artery occlusion (MCAO) in anesthetized animals. In EA group, EA preconditioning was performed, and the acupoint Baihui (GV20) was stimulated for 30 min with disperse-dense waves, the intensity of 1 mA and frequency of 2/15 Hz once a day for 5 consecutive days, and the model of cerebral I/R injury was developed at 24 h after the last EA. In AM251+ EA group, CB1R antagonist AM251 1 mg/kg was intraperitoneally injected at 30 min before each stimulation, and the remaining operations were the same as those previously described in EA group. CB1R agonist WIN 55, 212-2 1.5 mg/kg was intraperitoneally injected for 5 consecutive days, and the model of cerebral I/R injury was prepared at 24 h after the last injection in WIN group. Neurological behavior was assessed and scored at 3 days of reperfusion. Then the rats were sacrificed, and brains were removed, and the infarct volume was measured by TTC staining, and the tissues in the ischemic penumbra were extracted for determination of the expression of NLRP3, caspase-1 and interleukin-1bata (IL-1β) by Western blot. Results:Compared with Sham group, the percentage of cerebral infarct volume was significantly increased, the neurobehavioral score was decreased, and the expression of NLRP3, caspase-1 and IL-1β was up-regulated in I/R group ( P<0.05). Compared with I/R group, the percentage of cerebral infarct volume was significantly decreased, the neurobehavioral score was increased, and the expression of NLRP3, caspase-1 and IL-1β was down-regulated in EA and WIN groups ( P<0.05). Compared with EA group, the percentage of cerebral infarct volume was significantly increased, the neurobehavioral score was decreased, and the expression of NLRP3, caspase-1 and IL-1β was up-regulated in AM251+ EA group ( P<0.05). Conclusions:EA preconditioning may inhibit the activation of NLRP3 inflammasomes by activating CB1R, thus alleviating cerebral I/R injury in rats.

Relationship between Sestrin2 and mtDNA-NLRP3 inflammasome pathway during endotoxin-induced myocardial injury in mice / 中华麻醉学杂志

Objective:To evaluate the relationship between Sestrin2 and mitochondrial DNA (mtDNA)-NOD-like receptor associated protein 3 (NLRP3) inflammasome pathway during endotoxin-induced myocardial injury in mice.Methods:One hundred and eighty-four clean-grade healthy male ICR mice, aged 8-12 weeks, weighing 20-25 g, were used in this study. One hundred and sixty-eight mice were divided into 7 groups ( n=24 each) using the random number table method: normal control group (N group), lipopolysaccaride(LPS) group (L group), mtDNA group, LPS+ mtDNA group (M group), normal control+ negative control adeno-associated virus (AAV-NC)group (NC group), LPS+ mtDNA+ AAV-NC group (MC group), and LPS+ mtDNA+ Sestrin2 overexpression adeno-associated virus (AAV-Sestrin2) group (MSgroup). Another 10 mice were used to detect the transfection effect of AAV-Sestrin2, and the left 6 mice were used for mtDNA extraction. The model of endotoxemia was developed by intraperitoneal injection of LPS 10 mg/kg. mtDNA 5 mg/kg was intraperitoneally injected in mtDNA group, and mtDNA 5 mg/kg was intraperitoneally injected at 30 min after LPS injection in M group.AAV-Sestrin2 150 μl was injected via the tail vein in MS group, and the equal volume of AAV-NC was injected via the tail vein in MC and NC groups. Four weeks after virus injection, LPS 10 mg/kg was intraperitoneally injected and 30 min later mtDNA 5 mg/kg was intraperitoneally injected in MS and MC groups. Blood samples were collected at 24 h after LPS injection for determination of serum creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) activities (by biochemical assay), concentrations of serum cardiac troponin I (cTnI), interleukin-18 (IL-18) and interleukin-1beta (IL-1β)(by enzyme-linked immunesorbent assay), and expression of mtDNA (by quantitative real-time polymerase chain reaction). The animals were sacrificed after the end of blood sampling and myocardial tissues were obtained for determination of the contents of reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and adenosine triphosphate (ATP) and expression of NOD-like receptor associated protein 3 (NLRP3), active subunit p20 of caspase-1 (caspase-1p20) and apoptosis-associated microprotein (ASC) in myocardial tissues (by Western blot) and for microscopic examination of the pathological changes after HE staining (with a light microscope). Results:Compared with N group, the levels of CK-MB, LDH, cTnI, IL-1β and IL-18 in serum were significantly increased, the expression of mtDNA was up-regulated, the ROS content in myocardial tissues was increased, the T-AOC and ATP contents in myocardial tissues were decreased, the expression of NLRP3, caspase-1p20 and ASC in the myocardial tissues was up-regulated( P<0.05), and the pathological changes of myocardial tissues were aggravated in L group and mtDNA group.Compared with L group and mtDNA group, the levels of CK-MB, LDH, cTnI, IL-1β and IL-18 in serum were significantly increased, the expression of mtDNA was up-regulated, the ROS content in myocardial tissues was increased, the T-AOC and ATP contents in myocardial tissues were decreased, the expression of NLRP3, caspase-1p20 and ASC in the myocardial tissues was up-regulated( P<0.05), and the pathological changes of myocardial tissues were aggravated in M group. Compared with M group, the levels of CK-MB, LDH, cTnI, IL-1β and IL-18 in serum were significantly decreased, the expression of mtDNA was down-regulated, the ROS content in myocardial tissues was decreased, the T-AOC and ATP contents in myocardial tissues were increased, the expression of NLRP3, caspase-1p20 and ASC in the myocardial tissues was down-regulated( P<0.05), and the pathological changes of myocardial tissues were significantly attenuated in MS group. Conclusions:Sestrin2 can reduce endotoxin-induced myocardial injury in mice by alleviating mitochondrial damage, inhibiting oxidative stress, protecting mtDNA from oxidative damage, and then inhibiting mtDNA-NLRP3 inflammasome pathway.

The role of NLRP3/GATA-4/VEGF signal pathway in neovascular age-related macular degeneration / 中国医师杂志

Objective:To explore the potential role of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3)/GATA-binding protein 4 (GATA-4)/vascular endothelial growth factor (VEGF) signal pathway in neovascular age-related macular degeneration (nAMD).Methods:We applied the TRANSFAC Public database to search the human and mouse VEGF promoters and upstream transcription factors, analyzed the transcription factors that may influence the transcriptional activity of VEGF. The RAW264.7 cells were divided into control group and lipopolysaccharide (LPS) stimulated group (LPS group). Real time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to detect the activation of NLRP3 inflammasome, and the mRNA levels of GATA-4 and VEGFA. Thus, we applied the specific small molecular NLRP3 inhibitor MCC950 pretreated RAW264.7 cells (LPS+ MCC950 group), and detected the gene expression of NLRP3, Caspase-1, interleukin 1β( IL-1β), GATA-4 and VEGFA.Results:There were multiple GATA transcription factor binding sites upstream of human and mouse VEGF promoters. Compared with the control group, mRNA expression of NLRP3, Caspase-1, IL-1β, GATA-4 and VEGFA in LPS group were increased (all P<0.05). Compared with LPS group, mRNA expression of NLRP3, Caspase-1, IL-1β, GATA-4 and VEGFA in LPS+ MCC950 group were significantly decreased (all P<0.05). Conclusions:NLRP3/GATA-4/VEGF signal pathway may play a significant role in the pathologic processes of nAMD.

Protective effect of Guanxin Danshen formula on myocardial ischemiareperfusion injury in rats

Purpose: Myocardial ischemia/reperfusion injury (MIRI) leads to myocardial tissue necrosis, which will increase the size of myocardial infarction. The study examined the protective effect and mechanism of the Guanxin Danshen formula (GXDSF) on MIRI in rats. Methods: MIRI model was performed in rats; rat H9C2 cardiomyocytes were hypoxia-reoxygenated to establish a cell injury model. Results: The GXDSF significantly reduced myocardial ischemia area, reduced myocardial structural injury, decreased the levels of interleukin (IL-1ß, IL-6) in serum, decreased the activity of myocardial enzymes, increased the activity of superoxide dismutase (SOD), and reduced glutathione in rats with MIRI. The GXDSF can reduce the expression of nucleotide- binding oligomerization domain, leucine-rich repeat and pyrin domain containing nod-like receptor family protein 3 (NLRP3), IL-1ß, caspase-1, and gasdermin D (GSDMD) in myocardial tissue cells. Salvianolic acid B and notoginsenoside R1 protected H9C2 cardiomyocytes from hypoxia and reoxygenation injury and reduced the levels of tumor necrosis factor α (TNF-α) and IL-6 in the cell supernatant, decreasing the NLRP3, IL-18, IL-1ß, caspase-1, and GSDMD expression in H9C2 cardiomyocytes. GXDSF can reduce the myocardial infarction area and alleviate the damage to myocardial structure in rats with MIRI, which may be related to the regulation of the NLRP3. Conclusion: GXDSF reduces MIRI in rat myocardial infarction injury, improves structural damage in myocardial ischemia injury, and reduces myocardial tissue inflammation and oxidative stress by lowering inflammatory factors and controlling focal cell death signaling pathways.

Effect of electroacupuncture on inflammatory signal expression in local tissues of rats with chronic pelvic pain syndrome based on purinergic 2X7 receptor/NOD-like receptor pyrin domain-containing 3 signal pathway.

OBJECTIVES: To study the expression of inflammatory signal in local prostate tissue of chronic pelvic pain syndrome (CPPS) rats by electroacupuncture (EA) of Guanyuan (CV4), Zhongji (CV3), Huiyang (BL35) and Sanyinjiao (SP6), and to explore the possible mechanism of anti-inflammatory and analgesic effects of EA. METHODS：A total of 36 Sprague-Dawley male rats were randomly divided into three groups: control, model and EA (n=12 rats/group). The CPPS model was made by injection of CFA into ventral lobes of the prostate (0.1 mL). Electric acupuncture apparatus was applied to stimulate Guanyuan (CV4), Zhongji (CV3), bilateral Huiyang (BL35) and Sanyinjiao (SP6) acupoints in EA group. The general condition of rats was observed and the prostate index (PI) was calculated. The thermal pain threshold was collected after each therapeutic course. Histopathological changes of the prostate tissue were examined by hematoxylin-eosin staining method. The expression levels of tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß) and prostaglandin E2 (PGE2) in prostatic homogenates were measured by enzyme linked immunosorbent assay (ELISA). Moreover, the expression levels of purinergic 2X7 receptor (P2X7R), NOD-like receptor pyrin domain-containing 3 (NLRP3), caspase-1 and interleukin-18 (IL-18) mRNA were quantified by quantitative real-time polymerase chain reaction. RESULTS: Compared with control group, the PI of rats increased, and the thermal pain threshold decreased significantly in model group. The morphological structure of prostate tissues of rats in model group was severely damaged with a large number of inflammatory cells infiltration. Additionally, the levels of TNF-α, IL-1ß and PGE2 were higher, and the expressions of P2X7R, NLRP3, caspase-1 and IL-18 mRNA were higher than those in control group. After EA treatment, the PI was significantly decreased, the thermal pain threshold was significantly increased, and the tissue damage was significantly improved. The expressions of inflammatory cytokines were lower in EA group, and expression of P2X7R/NLRP3 pathway was down-regulated. CONCLUSION: The effect of EA at Guanyuan (CV4), Zhongji (CV3), Huiyang (BL35) and Sanyinjiao (SP6) can improve inflammation and pain symptoms of CPPS rats induced by Complete Freund's adjuvant (CFA). This suggests that EA at Guanyuan (CV4), Zhongji (CV3), Huiyang (BL35) and Sanyinjiao (SP6) can produce anti-inflammatory analgesia effect by preventing the activation of P2X7R/NLRP3 signal pathway, inhibit the release of inflammatory cytokines in CPPS rats, which may provide a putative novel target for the treatment of CPPS.

Ginsenoside Rb1 Reduces D-GalN/LPS-induced Acute Liver Injury by Regulating TLR4/NF-κB Signaling and NLRP3 Inflammasome.

Background and Aims: The effect of ginsenoside Rb1 on D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced acute liver injury (ALI) is unknown. The aim of this study was to evaluate the effect of ginsenoside Rb1 on ALI and its underlying mechanisms. Methods: Mice were pretreated with ginsenoside Rb1 by intraperitoneal injection for 3 days before D-GalN/LPS treatment, to induce ALI. The survival rate was monitored every hour for 24 h, and serum biochemical parameters, hepatic index and histopathological analysis were evaluated to measure the degree of liver injury. ELISA was used to detect oxidative stress and inflammatory cytokines in hepatic tissue and serum. Immunohistochemistry staining, RT-PCR and western blotting were performed to evaluate the expression of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), and NLR family, pyrin domain-containing 3 protein (NLRP3) in liver tissue and Kupffer cells (KCs). Results: Ginsenoside Rb1 improved survival with D-GalN/LPS-induced ALI by up to 80%, significantly ameliorated the increased alanine and aspartate transaminase, restored the hepatic pathological changes and reduced the levels of oxidative stress and inflammatory cytokines altered by D-GalN/LPS. Compared to the control group, the KCs were increased in the D-GalN/LPS groups but did not increase significantly with Rb1 pretreatment. D-GalN/LPS could upregulate while Rb1 pretreatment could downregulate the expression of interleukin (IL)-1ß, IL-18, NLRP3, apoptosis associated speck-like protein containing CARD (ASC) and caspase-1 in isolated KCs. Furthermore, ginsenoside Rb1 inhibited activation of the TLR4/NF-κB signaling pathway and NLRP3 inflammasome induced by D-GalN/LPS administration. Conclusions: Ginsenoside Rb1 protects mice against D-GalN/LPS-induced ALI by attenuating oxidative stress and the inflammatory response through the TLR4/NF-κB signaling pathway and NLRP3 inflammasome activation.

NLRP3 inflammasome and its role in age-related macular degeneration / 中华实验眼科杂志

Age-related macular degeneration (AMD), the leading cause of central vision loss among people aged 50 years and older, is one of the major eye diseases causing blindness in the world.Clinically, advanced AMD is divided into two types, non-exudative AMD with manifestation of geographic atrophy and exudative AMD with manifestation of choroidal neovascularization.The pathogenesis of AMD is complex, and the para-inflammation is recognized as an important risk factor.Nucleotide-binding oligomerization domain like receptors 3 (NLRP3) inflammasome is a cytoplasmic pattern recognition receptor and is expressed in several kings of cells, including retinal pigment epithelium (RPE) cells, microglial cells, Müller glia cells and retinal vascular endothelial cells.Recent studies have suggested that NLRP3 inflammasome plays an important role in the pathophysiology of both non-exudative and exudative AMD.The role of the NLRP3 inflammasome and its effector cytokines interleukin (IL)-1β and IL-18 in AMD were reviewed in this article to provide guidance on future prevention and therapy of AMD.

Effect of ROS/NLRP3/Caspase-1 signaling pathway on the apoptosis of retinal pigment epithelial cells induced by high glucose / 中华实验眼科杂志

Objective:To investigate the effect of the nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3 (NLRP3) inflammasome on the proliferation and apoptosis of human retinal pigment epithelial cell line ARPE-19 exposed to high glucose and its mechanism.Methods:ARPE-19 cells cultured in vitro were divided into normal control group and high-glucose group, and were cultured in conventional medium and medium containing 30 mmol/L glucose for 48 hours, respectively.The content of reactive oxygen species (ROS) were detected by fluorescent probe, and the activity of superoxide dismutase (SOD) and the concentration of malondialdehyde (MDA) were tested by biochemical assay.The cells of the two groups were cultured with 0, 2, 5, 10, 15 and 20 μmol/L NLRP3 inhibitor CY-09 for 48 hours, respectively.The proliferation rate of ARPE-19 cells under various concentrations of CY-09 treatment was detected by cell counting kit-8, and the appropriate concentration of CY-09 was determined.ARPE-19 cells were divided into normal control group, normal+ CY-09 group, high-glucose group and high glucose+ CY-09 group.The culture medium in the normal+ CY-09 group and high glucose+ CY-09 group was supplemented with 15 μmol/L CY-09.Flow cytometry was used to detect the apoptosis rate of each group, and Western blot was used to detect the relative expression levels of NLRP3, apoptosis-associated point protein (ASC), Caspase-1 precursor (pro-Caspase-1) and active fragments (cleaved-Caspase-1), B lymphocytoma-2 protein (Bcl-2), Bcl-2-associated X protein (Bax), Caspase-3 precursor (pro-Caspase-3) and active fragments (cleaved-Caspase-3). Results:The intensity of ROS fluorescence and MDA concentration were 120 020±3 245, (4.92±0.09) nmol/mg in the high-glucose group, which were both significantly higher than 35 426±811 and (1.78±0.03) nmol/mg in the normal control group, and the SOD activity was (35.65±1.22) μmol/(min·mg) in the high-glucose group, which was significantly lower than (74.96±1.41) μmol/(min·mg) in the normal control group, showing statistically significant differences between the two groups ( t=35.760, 46.960, 29.830; all at P<0.05). The proliferation rate of RPE cells in high-glucose group was significantly lower than that in normal control group, and the difference was statistically significant ( t=18.820, P<0.05). With the increase of CY-09 concentration, the proliferation rate of cells in the high-glucose group was gradually increased.The proliferation rates of cells treated with 10, 15 and 20 μmol/L CY-09 were all significantly higher than those treated with 0 μmol/L CY-09, showing statistically significant differences between them (all at P<0.05). The proliferation rates of cells treated with 15 μmol/L and 0 μmol/L CY-09 were not significantly different in the normal control group ( P>0.05). The apoptosis rate of cells in the high-glucose group was (21.68±0.41)%, which was significantly higher than (6.67±1.05)% in the normal control group and (13.96±0.07)% in the high-glucose+ CY-09 group, and the differences were statistically significant (both at P<0.05). The relative expression levels of NLRP3, ASC, cleaved-Caspase-1, cleaved-Caspase-3 and Bax proteins were significantly higher and the relative expression levels of Bcl-2 protein was significantly lower in the high-glucose group compared with the normal control group, and the differences were statistically significant (all at P<0.05). The relative expression levels of NLRP3, ASC, the active fragment of cleaved-Caspase-1, Bax and cleaved-Caspase-3 proteins were decreased and the relative expression levels of Bcl-2 protein were increased in the normal+ CY-09 group and high glucose+ CY-09 group compared with the normal control group and high glucose group, and the differences were statistically significant (all at P<0.05). Conclusions:NLRP3 inflammasome mediates the high glucose induced RPE cells apoptosis through ROS/NLRP3/Caspase-1 signaling pathway.