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Inflammation is a key response to a variety of stimuli, and inflammatory molecules such as cytokines play a central role in the pathogenesis of many diseases, including bone and joint diseases. Proinflammatory cytokines are mainly produced by immune cells, which mediate inflammation and innate immune responses. Inflammasomes are newly recognized as important players in innate immunity. The most typical one is the NOD-like receptor protein 3 (NLRP3) inflammasome. NLRP3 detects exogenous pathogenic invasion and endogenous cell damage and responds by forming the NLRP3 inflammasome. The three main components of the NLRP3 inflammasome are NLRP3 (capturing danger signals and recruits downstream molecules), caspase-1 (inducing the maturation of cytokines IL-18 and IL-18 to mediate the release and focal death of cytokines) and apoptosis-related spot-like protein containing caspase recruitment domain (ASC, which connects NLRP3 and caspase-1). In addition, proinflammatory cytokines accelerate bone absorption and cartilage destruction, leading to bone and joint tissue destruction. Therefore, proinflammatory cytokines are involved in regulating the pathogenesis of bone and joint diseases. This paper reviewed the research progress on the activation and function of NLRP3 inflammatory corpuscles in bone and joint diseases in recent years. [ABSTRACT FROM AUTHOR]

Objective To investigate the role of sodium-hyaluronate-modified calcium peroxide nanoparticles (SH-CaO2 NPs) in inducing pyroptosis in human gastric cancer cells and its possible mechanisms. Methods Transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy, and zeta potential test were used to confirm the synthesis of SH-CaO2 NPs. Cell scratch assay and CCK-8 assay were employed to observe the impacts of SH-CaO2 NPs on the migration and proliferation of human gastric cancer cell line HGC-27. The generation of reactive oxygen species (ROS) was observed with confocal laser scanning microscopy (CLSM) and quantified with flow cytometry in the cells after SH-CaO2 NPs treatment or with pretreatment with ROS inhibitor NAC. Furthermore, the effects of pretreatment of NLRP3 inhibitor (MCC950) and Caspase-1 inhibitor (VX765) on the proliferative activity and on expression of their own and their downstream GSDMD in HGC-27 cells were also investigated with CCK-8 assay, immunofluorescence assay and Western blotting. Results TEM images, XRD, infrared spectroscopy, and zeta potential test confirmed the successful preparation of SH-CaO2 NPs. Cell scratch assay and CCK-8 assay showed that application of SH-CaO2 NPs for 24 h significantly inhibited the proliferation of HGC-27 cells (P < 0.001), while, CLSM and flow cytometry indicated the treatment also promoted the production of ROS (P < 0.001). Pretreatment of ROS inhibitor NAC resulted in up-regulation of NLRP3, and increased expression levels of cleaved Caspase-1 and N-terminal fragment of GSDMD (P < 0.001), while pretreatment of both NLRP3 inhibitor and Caspase-1 inhibitor could reverse the process. Conclusion SH-CaO2 NPs inhibit cell viability of human gastric cancer, which may mediate the inflammatory response and pyroptosis by activating the ROS/NLRP3/Caspase-1/GSDMD signaling pathway.

Introduction: NOD-like receptor protein 3 (NLRP3) is implicated in chronic obstructive pulmonary disease (COPD) pathogenesis. Here, we explored the role of NLRP3 in cigarette smoke (CS)-induced airway inflammation in COPD. Material and methods: NLRP3 expression level was assessed with the microarray data in GEO datasets and validated in serum by ELISA from a case-control cohort. Male C57BL/6J mice were randomly divided into: saline, CS, MCC950 (a specific NLRP3 inhibitor, 10 mg/kg) and CS + MCC950 (5 mg/kg and 10 mg/kg) groups (n = 5 per group). All mice were exposed to CS or air for 4 weeks. Then, broncho-alveolar lavage (BAL) fluid and lung tissues were collected for cell counting, ELISA, HE staining and RNA sequencing with validation by real-time qPCR. Results: Compared to non-smokers, NLRP3 expression was significantly elevated in the lung tissues and sera of COPD smokers. CS remarkably induced airway inflammation in mice, characterized by an increase of inflammatory cells and proinflammatory cytokines in BAL fluid and HE inflammatory score, which were ameliorated by MCC950 treatment dose-dependently. Subsequently, 84 candidate genes were selected following RNA sequencing, and five hub genes (Mmp9, IL-1a, Cxcr2, Cxcl10, Ccr1) were then identified by PPI and MCODE analyses, which were confirmed by real-time qPCR. GO and KEGG analysis suggested that the five genes were enriched in a complicated network of inflammatory processes and signaling pathways. Conclusions: NLRP3 expression is elevated in lungs and sera of COPD smokers. Inhibition of NLRP3 significantly attenuates CS-induced airway inflammation in mice via inactivation of multiple hub genes and their related inflammatory processes and signaling pathways. [ABSTRACT FROM AUTHOR]

Excessive inflammatory response and oxidative stress (OS) play an important role in the pathogenesis of spinal cord injury (SCI). Balance of inflammation and prevention of OS have been considered an effective strategy for the treatment of SCI. Hyaluronan and proteoglycan link protein 1 (HAPLN1), also known as cartilage link protein, has displayed a wide range of biological and physiological functions in different types of tissues and cells. However, whether HAPLN1 regulates inflammation and OS during SCI is unknown. Therefore, we aimed to examine whether HAPLN1 can have a protective effect on SCI. In this study, both in vitro and in vivo SCI models were established. Nissl staining and terminal deoxynucleotidyl transferase dUTP nick end labeling staining assays were used. Western blotting and enzyme‐linked immunosorbent assay were employed to assess the expression of proteins. Our results demonstrate that the administration of HAPLN1 promoted the recovery of motor neurons after SCI by increasing the Basso mouse scale score, increasing the numbers of motor neurons, and preventing apoptosis of spinal cord cells. Additionally, HAPLN1 mitigated OS in spinal cord tissue after SCI by increasing the content of superoxide dismutase SOD and the activity of glutathione peroxidase but reducing the levels of malondialdehyde. Importantly, we found that HAPLN1 stimulated the activation of the nuclear factor erythroid 2‐related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and stimulated the expression of heme oxygenase‐1 and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase‐1, which mediated the attenuation of HAPLN1 in activation of the NOD‐like receptor protein 3 (NLRP3) inflammasome by reducing the levels of NLRP3, apoptosis‐associated speck‐like protein containing a caspase recruitment domain (ASC), caspase‐1, and interleukin‐1β. Correspondingly, in vitro experiments show that the presence of HAPLN1 suppressed the NLRP3 inflammasome and prevented cell injury against H2O2 in PC12 cells. These effects were mediated by the Nrf2/ARE pathway, and inhibition of Nrf2 with ML385 abolished the beneficial effects of HAPLN1. Based on these findings, we conclude that HAPLN1 inhibits the NLRP3 inflammasome through the stimulation of the Nrf2/ARE pathway, thereby suppressing neuroinflammation, enhancing motor neuronal survival, and improving the recovery of nerve function after SCI. [ABSTRACT FROM AUTHOR]

Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome signaling pathway is an important mechanism underlying myocardial pyroptosis and plays an important role in inflammatory damage to myocardial tissue in patients with cardiovascular diseases (CVDs), such as diabetic cardiomyopathy, ischemia/reperfusion injury, myocardial infarction, heart failure and hypertension. Noncoding RNAs (ncRNAs) are important regulatory factors. Many Chinese medicine (CM) compounds, including their effective components, can regulate pyroptosis and exert myocardium-protecting effects. The mechanisms underlying this protection include inhibition of inflammasome protein expression, Toll-like receptor 4–NF-κB signal pathway activation, oxidative stress, endoplasmic reticulum stress (ERS), and mixed lineage kinase 3 expression and the regulation of silent information regulator 1. The NLRP3 protein is an important regulatory target for CVD prevention and treatment with CM. Exploring the effects of the interventions mediated by CM and the related mechanisms provides new ideas and perspectives for CVD prevention and treatment. [ABSTRACT FROM AUTHOR]

Objective: To investigate the protective effect of dexmedetomidine (DEX) on myocardial ischemia-reperfusion injury in diabetic mice and its possible molecular mechanism. Methods: Sixty 8-week-old SPF C57BL mice were fed with high fat for 6 weeks. At the 7th week, the type 2 diabetes model was established by intraperitoneal injection of streptozotocin (STZ) 45 mg/kg/d once a day for5 days. After modeling, the mice were randomly divided into sham operation group (sham group), ischemia-reperfusion group (I/R group), hypoxia-inducible factor-1α (HIF-1α) inhibitor 2ME2 group (2ME2 group), DEX group and DEX+2ME2 group (DM group), with 12mice in each group. In sham group, the skin was only cut and sutured. In the other four groups, the left anterior descending coronary artery was ligated through thoracotomy, and the ligating wire was released after 60 minutes of ischemia, followed by 120 minutes of reperfusion to establish the ischemia-reperfusion injury model. Blood samples were collected from the abdominal aorta at 120 min of reperfusion for determination of serum concentrations of troponin I (cTnI), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α)by ELISA. Then the mice were sacrificed and left ventricles were isolated for observation of morphology and structure of myocardium by HE staining. The expression of HIF-1α and NOD-like receptor protein 3 (NLRP3) was detected by Western blot. Cardiac function was assessed by echocardiography at 24 h of reperfusion. Results: Compared with sham group, the concentrations of cTnI, IL-1β and TNF-α were significantly increased, myocardial tissue structure disorder, myocardial fiber rupture, myocardial cell swelling, inflammatory cell infiltration were significantly increased, the expression of NLRP3 in myocardial tissue was significantly increased, and stroke volume (SV), ejection fraction (EF) % and fractional shortening (FS) % were significantly decreased in I/R, 2ME2, DEX and DM groups (P＜0.05).Compared with I/R group, the expression of HIF-1α was significantly increased, the expression of NLRP3 was significantly decreased, the concentrations of cTnI, IL-1β and TNF-α were significantly decreased, myocardial tissue structure was significantly improved, inflammatory cell infiltration was significantly decreased, SV, EF and FS were significantly increased in DEX and DM groups (P＜0.05). Compared with the DEX group, the expression of HIF-1α was significantly decreased, the expression of NLRP3 was significantly increased, the concentrations of cTnI, IL-1β and TNF-α were significantly increased, myocardial tissue structure disorder, myocardial fiber rupture, myocardial cell swelling, inflammatory cell infiltration were significantly increased, SV, EF and FS were significantly decreased in the DM group (P＜0.05). Conclusions: DEX can alleviate myocardial I/R injury in diabetic mice by up-regulating HIF-1α, inhibiting the activation of NLRP3 inflammasome and reducing inflammatory response. [ABSTRACT FROM AUTHOR]

Knee osteoarthritis (KOA) is a major cause of disability in elderly individuals. Dicoumarol is a coumarin-like compound derived from sweet clover [Melilotus officinalis (L.) Pall]. It has been suggested that dicoumarol exhibits various types of pharmacological activities, including anticoagulant, antitumor and antibacterial effects. Due to its various biological activities, dicoumarol has a potential protective effect against OA. Therefore, the present study aimed to assess the effects of dicoumarol on knee osteoarthritis. In the present study, dicoumarol was found to protect rat synoviocytes from lipopolysaccharide (LPS)-induced cell apoptosis. Western blot analysis showed that dicoumarol significantly reduced the protein expression levels of fibrosis-related markers and inflammatory cytokines (Tgfb, Timp, Col1a, Il1b and Il18). The inhibitory rates of these proteins were all >50% (P<0.01) compared with those in the LPS and ATP-induced group. Consistently, the mRNA expression levels of these markers and cytokines were decreased to normal levels by dicoumarol after the treatment of rat synovial fibroblasts with LPS and ATP. Mechanistic studies demonstrated that dicoumarol did not affect NF-κB signaling, but it did directly interact with NOD-like receptor protein 3 (NLRP3) to promote its protein degradation, which could be reversed by MG132, but not NH4Cl. The protein half-life of NLRP3 was accelerated from 26.1 to 4.3 h by dicoumarol. Subsequently, dicoumarol could alleviate KOA in vivo; knee joint diameter was decreased from 11.03 to 9.93 mm. Furthermore, the inflammation and fibrosis of the knee joints were inhibited in rats. In conclusion, the present findings demonstrated that dicoumarol could impede the progression of KOA by inhibiting NLRP3 activation, providing a potential treatment strategy for KOA. [ABSTRACT FROM AUTHOR]

Endothelial cell dysfunction is the main pathology of atherosclerosis (AS). Sirtuin 6 (SIRT6), a deacetylase, is involved in AS progression. This study aimed to investigate the impacts of SIRT6 on the pyroptosis of endothelial cells and its underlying mechanisms. ApoE-/- mice were fed a high-fat diet (HFD) to establish the AS mouse model, atherosclerotic lesions were evaluated using oil red O staining, and blood lipids and inflammatory factors were measured using corresponding kits. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to establish the cell model, and pyroptosis was evaluated by flow cytometry, ELISA, and western blot. Immunoprecipitation (IP), co-IP, western blot, and immunofluorescence were used to detect the molecular mechanisms. The results showed that SIRT6 expression was downregulated in the blood of HFD-induced mice and ox-LDL-induced HUVECs. Overexpression of SIRT6 reduced atherosclerotic lesions, blood lipids, and inflammation in vivo and suppressed pyroptosis of HUVECs in vitro. Moreover, SIRT6 interacted with ASC to inhibit the acetylation of ASC, thus, reducing the interaction between ASC and NLRP3. Moreover, SIRT6 inhibits endothelial cell pyroptosis in the aortic roots of mice by deacetylating ASC. In conclusion, SIRT6 deacetylated ASC to inhibit its interaction with NLRP3 and then suppressed pyroptosis of endothelial cells, thus, decelerating the progression of AS. The findings provide new insights into the function of SIRT6 in AS.

Introduction: NOD-like receptor protein 3 (NLRP3) is implicated in chronic obstructive pulmonary disease (COPD) pathogenesis. Here, we explored the role of NLRP3 in cigarette smoke (CS)-induced airway inflammation in COPD., Material and Methods: NLRP3 expression level was assessed with the microarray data in GEO datasets and validated in serum by ELISA from a case-control cohort. Male C57BL/6J mice were randomly divided into: saline, CS, MCC950 (a specific NLRP3 inhibitor, 10 mg/kg) and CS + MCC950 (5 mg/kg and 10 mg/kg) groups ( n = 5 per group). All mice were exposed to CS or air for 4 weeks. Then, broncho-alveolar lavage (BAL) fluid and lung tissues were collected for cell counting, ELISA, HE staining and RNA sequencing with validation by real-time qPCR., Results: Compared to non-smokers, NLRP3 expression was significantly elevated in the lung tissues and sera of COPD smokers. CS remarkably induced airway inflammation in mice, characterized by an increase of inflammatory cells and proinflammatory cytokines in BAL fluid and HE inflammatory score, which were ameliorated by MCC950 treatment dose-dependently. Subsequently, 84 candidate genes were selected following RNA sequencing, and five hub genes (Mmp9, IL-1α, Cxcr2, Cxcl10, Ccr1) were then identified by PPI and MCODE analyses, which were confirmed by real-time qPCR. GO and KEGG analysis suggested that the five genes were enriched in a complicated network of inflammatory processes and signaling pathways., Conclusions: NLRP3 expression is elevated in lungs and sera of COPD smokers. Inhibition of NLRP3 significantly attenuates CS-induced airway inflammation in mice via inactivation of multiple hub genes and their related inflammatory processes and signaling pathways., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 Termedia & Banach.)

• NP induced the decline of spatial learning and memory and motor ability in rats. • NP led to the down-regulation of miR-542-3p and pyroptosis in substantia nigra. • Up-regulation of miR-542-3p targetd TLR4 and inhibit NP-induced microglial pyroptosis. This study aimed to investigate the spatial learning/memory and motor abilities of rats and the alteration of miR-542-3p and pyroptosis in the midbrain nigrostriatal area in vivo after nonylphenol (NP) gavage and to explore the mechanism of miR-542-3p regulation of Toll-like receptor 4 (TLR4) in NP-induced pyroptosis in BV2 microglia in vitro. In vivo : Thirty-six specific-pathogen-free-grade Sprague–Dawley rats were divided into three equal groups: blank control group (treated with pure corn oil), NP group (treated with NP, 80 mg/kg body weight per day for 90 days), and positive control group [treated with lipopolysaccharide (LPS), 2 mg/kg body weight for 7 days]. In vitro : The first part of the experiment was divided into blank group (control, saline), LPS group [1 µg/ml + 1 mM adenosine triphosphate (ATP)], and NP group (40 µmol/L). The second part was divided into mimics NC (negative control) group, miR-542-3p mimics group, mimics NC + NP group, and miR-542-3p mimics + NP group. In vivo : Behaviorally, the spatial learning/memory and motor abilities of rats after NP exposure declined, as detected via Y-maze, open field, and rotarod tests. Some microglia in the substantia nigra of the NP-treated rats were activated. The downregulation of miR-542-3p was observed in rat brain tissue after NP exposure. The mRNA/protein expression of pyroptosis-related indicators (TLR4), NOD-like receptor protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), gasdermin-D (GSDMD), cysteinyl aspartate–specific proteinase-1 (caspase-1), and interleukin-1β (IL-1β) in the substantia nigra of the midbrain increased after NP exposure. In vitro : ASC fluorescence intensity increased in BV2 cells after NP exposure. The mRNA and/or protein expression of pyroptosis-related indicators (TLR4, NLRP3, GSDMD, caspase-1, and IL-1β) in BV2 cells was upregulated after NP exposure. The transfection of miR-542-3p mimics inhibited NP-induced ASC expression in BV2 cells. The overexpression of miR-542-3p, followed by NP exposure, significantly reduced TLR4, NLRP3, ASC, caspase-1, and IL-1β gene and/or protein expression. This study suggested that NP exposure caused a decline in spatial learning memory and whole-body motor ability in rats. Our study was novel in reporting that the upregulation of miR-542-3p targeting and regulating TLR4 could inhibit NLRP3 inflammatory activation and alleviate NP-induced microglia pyroptosis. [Display omitted] [ABSTRACT FROM AUTHOR]