Inhibiting NLRP3 Inflammasome Activation Research Articles

Protective effect of lycorine hydrochloride against diabetic nephropathy in high-fat diet and streptozotocin-induced diabetic mice

Diabetic nephropathy (DN) poses a significant risk to individuals with diabetes. Inflammation plays a crucial role in DN pathogenesis. Lycorine hydrochloride (LH) is derived from Lycoris radiata (L'Hér.). This herb has been identified as a potent anti-inflammatory molecule. Further studies indicated that LH displayed therapeutic potential against metabolic disorders, renal dysfunction, and fibrosis in a high-fat diet and streptozotocin-induced (HFD/STZ)-induced DN mouse model. Mechanistically, LH mitigated renal inflammation in DN mice by targeting NF-κB pathways and the NLRP3 inflammasome verified by in vivo study. In vitro, LH inhibited NLRP3 inflammasome activation induced by nigericin (Ng), monosodium urate (MSU), and ATP, reduced caspase-1 activation, and IL-1β release. Additionally, LH suppressed the NF-κB IS-induced activation, prevented nuclear translocation of NF-κB, and subsequently reduced the expression of downstream proteins COX2 and iNOS. Collectively, these results indicated that LH primarily improved hyperglycemia-induced renal function by reducing inflammation by targeting NF-κB and NLRP3 inflammasome, implying it is a promising therapeutic agent for DN.

Inhibition of piezo1 prevents chronic cerebral hypoperfusion-induced cognitive impairment and blood brain barrier disruption

Chronic cerebral hypoperfusion (CCH) plays a critical role in the onset and progression of vascular dementia (VD), which is now recognized as the second most common form of dementia after Alzheimer's disease (AD). The mechanosensitive piezo1 channel has been identified to play important roles in several neurological disorders. However, the roles and possible mechanisms of piezo1 in CCH-induced cognitive decline and blood brain barrier (BBB) disruption, as well as the underlying mechanisms remain elusive. In this study, the CCH model was established by bilateral common carotid artery occlusion in rats and by oxygen and glucose deprivation/reoxygenation (OGD/R) in bEnd.3 cells. The results demonstrated that the antagonist of piezo1 GsMTx4 ameliorated CCH-induced cognitive dysfunction and mitigated cerebral edema. Furthermore, this study indicated that GsMTx4 improved the permeability and integrity of BBB and protected cerebral microvasculature after CCH. In vitro, GsMTx4 improved cell viability, promoted the ability of cell motility and migration, and inhibited the degradation of BBB integrity-related proteins by inhibiting NLRP3 inflammasome activation. In addition, NLRP3 agonist abolished the beneficial effects of GsMTx4. Collectively, our results demonstrate that piezo1 might be involved in CCH-induced cognitive impairment and BBB damage, which may be at least partially mediated through regulation of NLRP3 inflammasome.

Scutellarin inhibits oleic acid induced vascular smooth muscle foam cell formation via activating autophagy and inhibiting NLRP3 inflammasome activation.

Abnormalities in vascular smooth muscle cells (VSMCs) are pivotal in the pathogenesis of cardiovascular pathologies such as atherosclerosis and hypertension. Scutellarin (Scu), a flavonoid derived from marigold flowers, exhibits a spectrum of biological activities including anti-inflammatory, antioxidant, antitumor, immunomodulatory and antimicrobial effects. Notably, Scu has demonstrated the capacity to mitigate vascular endothelial damage and prevent atherosclerosis via its antioxidative properties. Nevertheless, the influence of Scu on the formation of VSMC-derived foam cells remains underexplored. In this study, Scu was evidenced to efficaciously attenuate oleic acid (OA)-induced lipid accumulation and the upregulation of adipose differentiation-associated protein Plin2 in a dose- and time-responsive manner. We elucidated that Scu effectively diminishes OA-provoked VSMC foam cell formation. Further, it was established that Scu pretreatment augments the protein expression of LC3B-II and the mRNA levels of Map1lc3b and Becn1, concurrently diminishing the protein levels of the NLRP3 inflammasome compared to the OA group. Activation of autophagy through rapamycin attenuated NLRP3 inflammasome protein expression, intracellular lipid droplet content and Plin2 mRNA levels. Scu also counteracted the OA-induced decrement of LC3B-II levels in the presence of bafilomycin-a1, facilitating the genesis of autophagosomes and autolysosomes. Complementarily, in vivo experiments revealed that Scu administration substantially reduced arterial wall thickness, vessel wall cross-sectional area, wall-to-lumen ratio and serum total cholesterol levels in comparison to the high-fat diet model group. Collectively, our findings suggest that Scu attenuates OA-induced VSMC foam cell formation through the induction of autophagy and the suppression of NLRP3 inflammasome activation.

Apelin-13 alleviates osteoclast formation and osteolysis through Nrf2-pyroptosis pathway.

Wear particle-induced periprosthetic osteolysis is the key to aseptic loosening after artificial joint replacement. Osteoclastogenesis plays a central role in this process. Apelin-13 is a member of the adipokine family with anti-inflammatory effects. Here, we report that apelin-13 alleviates RANKL-mediated osteoclast differentiation and titanium particle-induced osteolysis in mouse calvaria. Mechanistically, apelin-13 inhibits NLRP3 inflammasome-mediated pyroptosis by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In summary, apelin-13 is expected to be a potential drug for relieving aseptic osteolysis. RESEARCH HIGHLIGHTS: This study reveals the molecular mechanism by which apelin-13 inhibits NLRP3 inflammasome activation and pyroptosis by promoting Nrf2. This study confirms that apelin-13 alleviates osteoclast activation by inhibiting pyroptosis. In vivo studies further confirmed that apelin-13 alleviated mouse skull osteolysis by inhibiting the activation of NLRP3 inflammasome.

Dual-Atom Nanozyme Eye Drops Attenuate Inflammation and Break the Vicious Cycle in Dry Eye Disease

HighlightsA dual-atom nanozyme (DAN) was successfully prepared based on Fe and Mn bimetallic single-atom embedded in N-doped carbon material and modified with hydrophilic polymer.The DAN possess excellent enzyme catalytic activity and attenuate dramatically inflammation by inhibiting the reactive oxygen species (ROS)/NLRP3 signal axis.The DAN break the vicious cycle in dry eye disease and is a potential strategy for treating dry eye disease.

Isoliquiritigenin inhibits NLRP3 inflammasome activation with CAPS mutations by suppressing caspase-1 activation and mutated NLRP3 aggregation.

The nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain containing 3 (NLRP3) inflammasome contributes to the development of inflammatory diseases. Cryopyrin-associated periodic syndrome (CAPS) is an autoinflammatory disease caused by NLRP3 gene mutations that results in excessive IL-1β production. We previously identified isoliquiritigenin (ILG), a component of Glycyrrhiza uralensis extracts, as a potent inhibitor of the NLRP3 inflammasome. Here, we aimed to investigate whether ILG inhibits the activation of NLRP3 inflammasome caused by NLRP3 gene mutations. We demonstrated that ILG significantly inhibited NLRP3 inflammasome-mediated lactate dehydrogenase (LDH) release and IL-1β production in two CAPS model THP-1 cell lines, NLRP3-D303N and NLRP3-L353P, in a dose-dependent manner. Interestingly, the NLRP3 inhibitor MCC950 inhibited LDH release and IL-1β production in NLRP3-D303N cells, but not in NLRP3-L353P cells. Western blotting and caspase-1 activity assays showed that ILG, as well as caspase inhibitors, including Z-VAD and YVAD, suppressed caspase-1 activation. Notably, ILG prevented cryo-sensitive foci formation of NLRP3 without affecting the levels of intracellular Ca2+. We concluded that ILG effectively prevents the constitutive activation of the inflammasome associated with NLRP3 gene mutations by inhibiting the aggregation of cryo-sensitive mutated NLRP3.

Fluorofenidone attenuates renal fibrosis by inhibiting lysosomal cathepsin‑mediated NLRP3 inflammasome activation.

Currently, no antifibrotic drug in clinical use can effectively treat renal fibrosis. Fluorofenidone (AKFPD), a novel pyridone agent, significantly reduces renal fibrosis by inhibiting the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome; however, the underlying mechanism of this inhibition is not fully understood. The present study aimed to reveal the molecular mechanism underlying the suppression of NLRP3 inflammasome activation by AKFPD. It investigated the effect of AKFPD on NLRP3 activation and lysosomal cathepsins in a unilateral ureteral obstruction (UUO) rat model, and hypoxia/reoxygenation (H/R)-treated HK-2 cells and murine peritoneal-derived macrophages (PDMs) stimulated with lipopolysaccharide (LPS) and ATP. The results confirmed that AKFPD suppressed renal interstitial fibrosis and inflammation by inhibiting NLRP3 inflammasome activation in UUO rat kidney tissues. In addition, AKFPD reduced the production of activated caspase-1 and maturation of IL-1β by suppressing NLRP3 inflammasome activation in H/R-treated HK-2 cells and murine PDMs stimulated with LPS and ATP. AKFPD also decreased the activities of cathepsins B, L and S both in vivo and in vitro. Notably, AKFPD downregulated cathepsin B expression and NLRP3 colocalization in the cytoplasm after lysosomal disruptions. Overall, the results suggested that AKFPD attenuates renal fibrosis by inhibiting lysosomal cathepsin-mediated activation of the NLRP3 inflammasome.

Acacetin inhibits inflammation by blocking MAPK/NF-κB pathways and NLRP3 inflammasome activation.

Objective: Our preliminary research indicates that acacetin modulates the nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3) inflammasome, providing protection against Alzheimer's Disease (AD) and cerebral ischemic reperfusion injury. The mechanisms of acacetin to inhibit the activation of the NLRP3 inflammasome remain fully elucidated. This study aims to investigate the effects and potential mechanisms of acacetin on various agonists induced NLRP3 inflammasome activation. Methods: A model for the NLRP3 inflammasome activation was established in mouse bone marrow-derived macrophages (BMDMs) using Monosodium Urate (MSU), Nigericin, Adenosine Triphosphate (ATP), and Pam3CSK4, separately. Western blot analysis (WB) was employed to detect Pro-caspase-1, Pro-Interleukin-1β (Pro-IL-1β) in cell lysates, and caspase-1, IL-1β in supernatants. Enzyme-Linked Immunosorbent Assay (ELISA) was used to measured the release of IL-1β, IL-18, and Tumor Necrosis Factor-alpha (TNF-α) in cell supernatants to assess the impact of acacetin on NLRP3 inflammasome activation. The lactate dehydrogenase (LDH) release was also assessed. The Nuclear Factor Kappa B (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) signaling pathways related proteins were evaluated by WB, and NF-κB nuclear translocation was observed via laser scanning confocal microscopy (LSCM). Disuccinimidyl Suberate (DSS) cross-linking was employed to detect oligomerization of Apoptosis-associated Speck-like protein containing a Caspase Recruitment Domain (ASC), and LSCM was also used to observe Reactive Oxygen Species (ROS) production. Inductively Coupled Plasma (ICP) and N-(6-methoxyquinolyl) acetoethyl ester (MQAE) assays were utilized to determined the effects of acacetin on the efflux of potassium (K+) and chloride (Cl-) ions. Results: Acacetin inhibited NLRP3 inflammasome activation induced by various agonists, reducing the release of TNF-α, IL-1β, IL-18, and LDH. It suppressed the expression of Lipopolysaccharides (LPS)-activated Phosphorylated ERK (p-ERK), p-JNK, and p-p38, inhibited NF-κB p65 phosphorylation and nuclear translocation. Acacetin also reduced ROS production and inhibited ASC aggregation, thus suppressing NLRP3 inflammasome activation. Notably, acacetin did not affect K+ and Cl-ions efflux during the activation process. Conclusion: Acacetin shows inhibitory effects on both the priming and assembly processes of the NLRP3 inflammasome, positioning it as a promising new candidate for the treatment of NLRP3 inflammasome-related diseases.

Quercetin Ameliorates Cognitive Impairment in Depression by Targeting HSP90 to Inhibit NLRP3 Inflammasome Activation.

Cognitive dysfunction was a common symptom of major depressive disorder (MDD). In previous studies, psychological stress leads to activation and proliferation of microglial cells in different brain regions. Quercetin, a bioflavonoid derived from vegetables and fruits, exerts anti-inflammatory effects in various diseases. To demonstrate the role of quercetin in thehippocampal inflammatory response in depress mice. The chronic unpredictable stress (CUS) depressive mice model built is used to explore the protective effects of quercetin on depression. Neurobehavioral test, protein expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and heat shock protein 90 (HSP90), and cytokines (IL-6, IL-1β, MCP-1, and TNF-α) were assessed. Quercetin ameliorated depressive-like behavior and cognitive impairment, and quercetin attenuates neuroinflammation and by targeting HSP90 to inhibit NLRP3 inflammasome activation. Quercetin inhibited the increase of HSP90 levels in the hippocampus and reverses inflammation-induced cognitive impairment. Besides, quercetin inhibited the increased level of cytokines (IL-6, IL-1β, MCP-1, and TNF-α) in the hippocampus of the depressive model mouse and the increased level of cytokines (IL-6, IL-1β, and MCP-1) in microglia. The current study indicated that quercetin mitigated depressive-like behavior and by targeting HSP90 to inhibit NLRP3 inflammasome activation in microglia and depressive mice model, meanwhile ameliorated cognitive impairment in depression. Quercetin has huge potential for the novel pharmacological efficacy of antidepressant therapy.

METTL3 Mediates Microglial Activation and Blood-Brain Barrier Permeability in Cerebral Ischemic Stroke by Regulating NLRP3 Inflammasomes Through m6A Methylation Modification.

Cerebral ischemic stroke (CIS) is the main cause of disability. METTL3 is implicated in CIS, and we explored its specific mechanism. Middle cerebral artery occlusion (MCAO) rat model and oxygen-glucose deprivation/reperfusion (OGD/R) HAPI cell model were established and treated with LV-METTL3 or DAA, oe-METTL3, miR-335-3p mimics, or DAA, to assess their effects on MCAO rat neurological and motor function, cerebral infarction area, brain water content, microglial activation, blood-brain barrier (BBB) permeability, and NLRP3 inflammasome activation. METTL3, pri-miR-335-3p, mature miR-335-3p, and miR-335-3p mRNA levels were assessed by RT-qPCR; M1/M2 microglial phenotype proportion and M1/M2 microglia ratio, inflammatory factor levels, and m6A modification were assessed. MCAO rats manifested cerebral ischemia injury. METTL3 was under-expressed in CIS. METTL3 overexpression inhibited microglial activation and M1 polarization and BBB permeability in MCAO rats and inhibited OGD/R-induced microglial activation and reduced M1 polarization. METTL3 regulated miR-335-3p expression and inhibited NLRP3 inflammasome activation. m6A methylation inhibition averted METTL3's effects on NLRP3 activation, thus promoting microglial activation in OGD/R-induced cells and METTL3's effects on BBB permeability in MCAO rats. Briefly, METTL3 regulated miR-335-3p expression through RNA m6A methylation and inhibited NLRP3 inflammasome activation, thus repressing microglial activation, BBB permeability, and protecting against CIS.

Abstract WMP1: Neuroprotection by Normobaric Oxygen (NBO): Modulating Inflammasome (NLRP3) Activation and Stress Granule Formation in Ischemic Stroke

Background: NBO has emerged as a promising neuroprotective strategy for ischemic stroke. Key to comprehending these effects is understanding its mechanisms. This study examines the pivotal roles of HIF-1α as an oxygen sensor, the protective emergence of stress granules (SGs) in response to various stimuli, and the inflammatory cell death process known as pyroptosis, triggered by inflammasomes. We elucidated the interplay between HIF-1α, SGs, inflammasomes in ischemia/reperfusion injury and in NBO-induced neuroprotection. Methods: A total of 132 adult male SD rats were subjected to 2 h middle cerebral artery occlusion (MCAO), followed by 2, 6, 24 or 48 h of reperfusion. At the onset of reperfusion, oxygen was inhaled for 2 h at concentration of 95% and flow rate of 2 L/min. YC-1 (HIF-1α inhibitor) was administered 2 h before MCAO. Brain damage was evaluated by infarct volumes (TTC), LDH and ROS levels (ELISA), apoptotic cell death (flow cytometry and TUNEL). Pyroptosis was evaluated by flow cytometry. mRNA and protein levels of HIF-1α and inflammasome related factors, including IL-18, IL-1β, ASC, NLRP3, TXNIP, N-GSDMD, cleaved-Caspase-1, as well as SGs proteins including DDX3X, G3BP1, TIA-1 were examined. Co-IP was used to detect the interaction between DDX3X and G3BP1, as well as DDX3X and NLRP3. Results: Infarct volumes, LDH and ROS levels, apoptotic and pyroptotic cell death, as well as HIF-1α expression were all increased after ischemia/reperfusion. All these increases were reversed by either NBO or YC-1. NBO or YC-1 further reversed the increase in expression of NLRP3 inflammasome related proteins and suppressed the interaction between DDX3X and NLRP3, thereby suppressing inflammasome activation. NBO or YC-1 stimulated the expressions of SGs proteins and facilitated the interaction between DDX3X and G3BP1, thereby promoting the formation of SGs, in association with cell protection. Conclusion: Our findings highlight the neuroprotective effects of NBO in ischemic stroke. This protection is attributed to its dual capacity to inhibit NLRP3 inflammasome activation while simultaneously promoting formation of SGs. Central to these processes, HIF-1α, as an instrumental modulator, sheds light on potential therapeutic targets for stroke intervention.

Hepatic Zbtb18 (Zinc Finger and BTB Domain Containing 18) alleviates hepatic steatohepatitis via FXR (Farnesoid X Receptor)

A lasting imbalance between fatty acid synthesis and consumption leads to non-alcoholic fatty liver disease (NAFLD), coupled with hepatitis and insulin resistance. Yet the details of the underlying mechanisms are not fully understood. Here, we unraveled that the expression of the transcription factor Zbtb18 is markedly decreased in the livers of both patients and murine models of NAFLD. Hepatic Zbtb18 knockout promoted NAFLD features like impaired energy expenditure and fatty acid oxidation (FAO), and induced insulin resistance. Conversely, hepatic Zbtb18 overexpression alleviated hepato-steatosis, insulin resistance, and hyperglycemia in mice fed on a high-fat diet (HFD) or in diabetic mice. Notably, in vitro and in vivo mechanistic studies revealed that Zbtb18 transcriptional activation of Farnesoid X receptor (FXR) mediated FAO and Clathrin Heavy Chain (CLTC) protein hinders NLRP3 inflammasome activity. This key mechanism by which hepatocyte’s Zbtb18 expression alleviates NAFLD and consequent liver fibrosis was further verified by FXR’s deletion and forced expression in mice and cultured mouse primary hepatocytes (MPHs). Moreover, CLTC deletion significantly abrogated the hepatic Zbtb18 overexpression-driven inhibition of NLRP3 inflammasome activity in macrophages. Altogether, Zbtb18 transcriptionally activates the FXR-mediated FAO and CLTC expression, which inhibits NLRP3 inflammasome’s activity alleviating inflammatory stress and insulin resistance, representing an attractive remedy for hepatic steatosis and fibrosis.

Lactiplantibacillus plantarum postbiotic protects against Salmonella infection in broilers via modulating NLRP3 inflammasome and gut microbiota

Salmonella infection is a major concern in poultry production which poses potential risks to food safety. Our previous study confirmed that Lactiplantibacillus plantarum (LP) postbiotic exhibited a strong antibacterial capacity on Salmonella in vitro. This study aimed to investigate the beneficial effects and underlying mechanism of LP postbiotic on Salmonella-challenged broilers. A total of 240 one-day-old male yellow-feathered broilers were pretreated with 0.8% deMan Rogosa Sharpe (MRS) medium or 0.8% LP postbiotic (LP cell-free culture supernatant, LPC) in drinking water for 28 d, and then challenged with 1×109 CFU Salmonella enterica serovar Enteritidis (SE). Birds were sacrificed 3 d postinfection. Results showed that LPC maintained the growth performance by increasing body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) in broilers under SE challenge. LPC significantly attenuated SE-induced intestinal mucosal damage. Specifically, it decreased the intestinal injury score, increased villus length and villus/crypt, regulated the expression of intestinal injury-related genes (Villin, matrix metallopeptidase 3 [MMP3], intestinal fatty acid-binding protein [I-FABP]), and enhanced tight junctions (zona occludens-1 [ZO-1] and Claudin-1). SE infection caused a dramatic inflammatory response, as indicated by the up-regulated concentrations of interleukin (IL)-1β, IL-6, TNF-α, and the downregulation of IL-10, while LPC pretreatment markedly reversed this trend. We then found that LPC inhibited the activation of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome by decreasing the gene expression of Caspase-1, IL-lβ, and IL-18. Furthermore, LPC suppressed NLRP3 inflammasome activation by inhibiting nuclear factor-kappa B (NF-κB) signaling pathway (the reduced levels of toll-like receptor 4 [TLR4], myeloid differentiation factor 88 [MyD88], and NF-κB). Finally, our results showed that LPC regulated gut microbiota by enhancing the percentage of Ligilactobacillus and decreasing Alistipes and Barnesiella. In summary, we found that LP postbiotic was effective to protect broilers against Salmonella infection, possibly through suppressing NLRP3 inflammasome and optimizing gut microbiota. Our study provides the potential of postbiotics on prevention of Salmonella infection in poultry.

METTL3 Modulates TXNIP Expression to Affect the Activation of NLRP3 Inflammasome in Hepatic Cells Under Oxygen-Glucose Deprivation/Reperfusion Injury.

Hepatic ischemia-reperfusion (I/R) injury is still a major risk factor and unsolved problem in hepatic surgery. Methyltransferase-like 3 (METTL3), an important m6A-modified methylase, regulates inflammation and cellular stress response. In this study, we demonstrated the special role of METTL3 and its underlying mechanism in hepatic I/R injury. In the mouse model of hepatic I/R and in the oxygen-glucose deprivation and reoxygenation (OGD/R)-induced AML12 and NCTC 1469 cells, the expression of METTL3 was significantly upregulated. Inhibition of METTL3 in OGD/R-induced AML12 and NCTC 1469 cells both increased the cell viability, declined the cell apoptosis, and decreased the reactive oxygen species (ROS) and the release levels of interleukin-1β (IL-1β) and interleukin-18 (IL-18), diminishing NLRP3 and Caspase1-p20 expressions. Moreover, METTL3 positively modulated TXNIP expression in an m6A manner. TXNIP overexpression reversed the effects of METTL3 knockdown on OGD/R-induced injury in AML12 cells. Furthermore, inhibition of NLRP3 inflammasome activity contributed to the protective effects of TXNIP knockdown in OGD/R-induced AML12 cells. In conclusion, METTL3 knockdown alleviated OGD/R-induced hepatocyte injury, and the specific mechanism was associated with the inhibition of NLRP3 inflammasome activation, which was attributed to the reduction of TXNIP in an m6A-dependent manner.

Anastrozole Protects against Human Coronavirus Infection by Ameliorating the Reactive Oxygen Species-Mediated Inflammatory Response.

The common human coronavirus (HCoV) exhibits mild disease with upper respiratory infection and common cold symptoms. HCoV-OC43, one of the HCoVs, can be used to screen drug candidates against SARS-CoV-2. We determined the antiviral effects of FDA/EMA-approved drug anastrozole (AZ) on two human coronaviruses, HCoV-OC43 and HCoV-229E, using MRC-5 cells in vitro. The AZ exhibited antiviral effects against HCoV-OC43 and HCoV-229E infection. Subsequent studies focused on HCoV-OC43, which is related to the SARS-CoV-2 family. AZ exhibited anti-viral effects and reduced the secretion of inflammatory cytokines, TNF-α, IL-6, and IL-1β. It also inhibited NF-κB translocation to effectively suppress the inflammatory response. AZ reduced intracellular calcium and reactive oxygen species (ROS) levels, including mitochondrial ROS and Ca2+, induced by the virus. AZ inhibited the expression of NLRP3 inflammasome components and cleaved IL-1β, suggesting that it blocks NLRP3 inflammasome activation in HCoV-OC43-infected cells. Moreover, AZ enhanced cell viability and reduced the expression of cleaved gasdermin D (GSDMD), a marker of pyroptosis. Overall, we demonstrated that AZ exhibits antiviral activity against HCoV-OC43 and HCoV-229E. We specifically focused on its efficacy against HCoV-OC43 and showed its potential to reduce inflammation, inhibit NLRP3 inflammasome activation, mitigate mitochondrial dysfunction, and suppress pyroptosis in infected cells.

Antagonizing interleukin-5 receptor ameliorates dextran sulfate sodium-induced experimental colitis in mice through reducing NLRP3 inflammasome activation

Inflammatory bowel disease (IBD) is a condition characterized by inflammation in the gastrointestinal tract. Reducing intestinal inflammation is a promising approach for treating IBD. The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome, a critical component of the innate immune system, is implicated in the pathogenesis of IBD. Therefore, inhibiting NLRP3 inflammasome activation is a potential therapeutic strategy for IBD. In this study, we investigated the effects of the interleukin-5 (IL-5) receptor antagonist YM-90709 on dextran sulfate sodium-induced experimental colitis in mice. We found that YM-90709 reduced the expressions of IL-1β and caspase-1 p20 in the colon and ameliorated colitis. Furthermore, we identified YM-90709 as an effective agent for inhibiting NLRP3 inflammasome activation. Knockdown of IL-5 receptor or using an inhibitor of STAT5, a key transcription factor downstream of the IL-5/IL-5 receptor signal pathway, also reduced NLRP3 inflammasome-dependent IL-1β release and ASC speck formation. Our study is the first to demonstrate that the NLRP3 inflammasome may be a downstream signal of IL-5/IL-5 receptor and that YM-90709 protects against IBD by inhibiting IL-5 receptor. These findings suggest a new strategy for regulating intestinal inflammation and managing IBD.

ELAVL1 ameliorates sevoflurane induced neurotoxicity by inhibiting NLRP3 inflammasome activation

Purpose: To investigate the role of embryonic lethal-abnormal vision like protein 1 (ELAVL1) in sevoflurane-induced neurotoxicity.
 Methods: A cell model was established in HT22 cells by exposing them to 3 % sevoflurane for 12 h. The HT22 cells were transfected with siRNA ELAVL1 (si-ELAVL1) or siRNA negative control (si-NC) to knockdown ELAVL1 expression. Enzyme-linked immunosorbent assay (ELISA) was performed to assess the levels of proinflammatory factors in HT22 cell culture supernatants. Cell apoptosis was analyzed using flow cytometry while apoptosis-related proteins and NLRP3 inflammasome pathway proteins were determined by western blot.
 Results: ELAVL1 was upregulated in sevoflurane-exposed HT22 cells. Sevoflurane exposure also resulted in inflammation, apoptosis and activation of NLRP3 inflammasome of HT22 cells. Importantly, knockdown of ELAVL1 inhibited inflammation and apoptosis in HT22 cells caused by sevoflurane through the inhibition of IL-6, IL-1β and TNF-α production and bys regulating Bax and Bcl-2 protein expression. Furthermore, knockdown of ELAVL1 suppressed NLRP3 inflammasome activity as reflected by the inhibition of the expression of caspase 1, ASC, IL-1β and IL-18. 
 Conclusion: The findings of this study suggest that the knockdown of ELAVL1 alleviates the inflammation and apoptosis of HT22 cells induced by sevoflurane which impeded the activation of NLRP3 inflammasome, suggesting that ELAVL1 would make a good therapeutic target for sevoflurane-caused neurotoxicity.

Carnosol ameliorates sevoflurane induced cognitive impairment in aged rats by suppressing NLRP3 inflammasome via activation of autophagy

Purpose: To investigate the effect of carnosol on the progression of postoperative cognitive dysfunction (POCD) and to elucidate its mechanism of action.
 Methods: A cognitive impairment model rat induced by sevoflurane (SEV) was established. Dihydroethidium (DHE) assay was conducted to determine the effect of carnosol on reactive oxygen species (ROS) levels in sevoflurane-induced rats. Adenosine triphosphate (ATP) production and immunoblot assays were used to assess carnosol effect on mitochondrial damage, while water maze experiment was performed to evaluate cognitive dysfunction in the rats. The mechanism of action was investigated using immunoblot assay.
 Results: Carnosol suppressed sevoflurane-induced ROS production in the rats, and alleviated sevoflurane-induced mitochondrial damage; it also activated autophagy. Furthermore, carnosol suppressed SEV-induced NLRP3 inflammasome activation by activating autophagy and suppressing SEV-induced cognitive dysfunction via the suppression of NLRP3 inflammasome activation.
 Conclusion: Carnosol ameliorates SEV-stimulated cognitive impairment by suppressing NLRP3 inflammasome and thus, can potentially be developed serve as a therapeutic agent for the management of cognitive impairment.

Covalent Targeting As a Common Mechanism for Inhibiting NLRP3 Inflammasome Assembly.

The NLRP3 inflammasome is a cytosolic protein complex important for the regulation and secretion of inflammatory cytokines, including IL-1β and IL-18. Aberrant overactivation of NLRP3 is implicated in numerous inflammatory disorders. However, the activation and regulation of NLRP3 inflammasome signaling remain poorly understood, limiting our ability to develop pharmacologic approaches to target this important inflammatory complex. Here, we developed and implemented a high-throughput screen to identify compounds that inhibit the inflammasome assembly and activity. From this screen, we identify and profile inflammasome inhibition of 20 new covalent compounds across nine different chemical scaffolds, as well as many known inflammasome covalent inhibitors. Intriguingly, our results indicate that NLRP3 possesses numerous reactive cysteines on multiple domains whose covalent targeting blocks the activation of this inflammatory complex. Specifically, focusing on compound VLX1570, which possesses multiple electrophilic moieties, we demonstrate that this compound allows covalent, intermolecular cross-linking of NLRP3 cysteines to inhibit inflammasome assembly. Our results, along with the recent identification of numerous covalent molecules that inhibit NLRP3 inflammasome activation, further support the continued development of electrophilic compounds that target reactive cysteine residues on NLRP3 to regulate its activation and activity.

Intracellular and extracellular synergistic therapy for restoring macrophage functions via anti-CD47 antibody-conjugated bifunctional nanoparticles in atherosclerosis

Atherosclerosis is a significant contributor to global cardiovascular disease. Reducing the formation of atherosclerotic plaque effectively can lead to a decrease in cardiovascular diseases. Therefore, controlling macrophage function is crucial. This study presents the creation of a bifunctional nanoparticle that is specific to macrophages to achieve intracellular and extracellular synergistic therapy for restoring macrophage functions. The nanoparticle is conjugated with anti-CD47 antibody to modulate extracellular CD47-SIRPα phagocytic signaling axis on the outer surface of macrophages and encapsulates the NLRP3 inhibitor (CY-09) to regulate intracellular inflammation response of macrophages. The results showed that the nanoparticles accumulate in the atherosclerotic plaque, alter macrophage phagocytosis, inhibit NLRP3 inflammasome activation, and decrease the plaque burden in Apoe−/− mice whilst ensuring safety. Examination of single-cell RNA sequencing indicates that this multifunctional nanoparticle decreases the expression of genes linked to inflammation and manages inflammatory pathways in the plaque lesion. This study proposes a synergistic therapeutic approach that utilizes a bifunctional nanoparticle, conjugated with anti-CD47, to regulate the microenvironment of plaques.