3'-Deoxyadenosin alleviates methamphetamine-induced aberrant synaptic plasticity and seeking behavior by inhibiting the NLRP3 inflammasome

Methamphetamine addiction is a brain disorder characterized by persistent drug-seeking behavior, which has been linked with aberrant synaptic plasticity. An increasing body of evidence suggests that aberrant synaptic plasticity is associated with the activation of the NOD-like receptor family pyrin domain containing-3(NLRP3) inflammasome. 3′-Deoxyadenosin, an active component of the Chinese fungus Cordyceps militaris, has strong anti-inflammatory effects. However, whether 3′-deoxyadenosin attenuates methamphetamine-induced aberrant synaptic plasticity via an NLRP3-mediated inflammatory mechanism remains unclear. We first observed that 3′-deoxyadenosin attenuated conditioned place preference scores in methamphetamine-treated mice and decreased the expression of c-fos in hippocampal neurons. Furthermore, we found that 3′-deoxyadenosin reduced the aberrant potentiation of glutamatergic transmission and restored the methamphetamine-induced impairment of synaptic plasticity. We also found that 3′-deoxyadenosin decreased the expression of NLRP3 and neuronal injury. Importantly, a direct NLRP3 deficiency reduced methamphetamine-induced seeking behavior, attenuated the impaired synaptic plasticity, and prevented neuronal damage. Finally, NLRP3 activation reversed the effect of 3′-deoxyadenosin on behavior and synaptic plasticity, suggesting that the anti-neuroinflammatory mechanism of 3′-deoxyadenosin on aberrant synaptic plasticity reduces methamphetamine-induced seeking behavior. Taken together, 3′-deoxyadenosin alleviates methamphetamine-induced aberrant synaptic plasticity and seeking behavior by inhibiting the NLRP3 inflammasome.

Microglial NLRP3 inflammasome-mediated neuroinflammation and therapeutic strategies in depression

Previous studies have demonstrated a bidirectional relationship between inflammation and depression.Activation of the nucleotide-binding oligomerization domain,leucine-rich repeat,and NLR family pyrin domain-containing 3(NLRP3)inflammasomes is closely related to the pathogenesis of various neurological diseases.In patients with major depressive disorder,NLRP3 inflammasome levels are significantly elevated.Understanding the role that NLRP3 inflammasome-mediated neuroinflammation plays in the pathogenesis of depression may be beneficial for future therapeutic strategies.In this review,we aimed to elucidate the mechanisms that lead to the activation of the NLRP3 inflammasome in depression as well as to provide insight into therapeutic strategies that target the NLRP3 inflammasome.Moreover,we outlined various therapeutic strategies that target the NLRP3 inflammasome,including NLRP3 inflammatory pathway inhibitors,natural compounds,and other therapeutic compounds that have been shown to be effective in treating depression.Additionally,we summarized the application of NLRP3 inflammasome inhibitors in clinical trials related to depression.Currently,there is a scarcity of clinical trials dedicated to investigating the applications of NLRP3 inflammasome inhibitors in depression treatment.The modulation of NLRP3 inflammasomes in microglia holds promise for the management of depression.Further investigations are necessary to ascertain the efficacy and safety of these therapeutic approaches as potential novel antidepressant treatments.

SLC6A14 promotes ulcerative colitis progression by facilitating NLRP3 inflammasome-mediated pyroptosis

BACKGROUND Ulcerative colitis(UC)is an inflammatory condition with frequent relapse and recurrence.Evidence suggests the involvement of SLC6A14 in UC pathogenesis,but the central regulator remains unknown.AIM To explore the role of SLC6A14 in UC-associated pyroptosis.METHODS Quantitative real-time polymerase chain reaction(qRT-PCR),immunoblotting,and immunohistochemical were used to assess SLC6A14 in human UC tissues.Lipopolysaccharide(LPS)was used to induce inflammation in FHC and NCM460 cells and model enteritis,and SLC6A14 levels were assessed.Pyroptosis markers were quantified using enzyme-linked immunosorbent assay,Western blotting,and qRT-PCR,and EdU incubation,CCK-8 assays and flow cytometry were used to examine proliferation and apoptosis.Mouse models of UC were used for verification.RESULTS SLC6A14 was increased and correlated with NLRP3 in UC tissues.LPS-induced FHC and NCM460 cells showed increased SLC6A14 levels.Reducing SLC6A14 increased cell proliferation and suppressed apoptosis.Reducing SLC6A14 decreased pyroptosis-associated proteins(ASC,IL-1β,IL-18,NLRP3).NLRP3 overexpression counteracted the effects of sh-SLC6A14 on LPS-induced FHC and NCM460 cell pyroptosis.SLC6A14 improved the mucosa in mice with dextran sulfate sodium-induced colitis.CONCLUSION SLC6A14 promotes UC pyroptosis by regulating NLRP3,suggesting the therapeutic potential of modulating the SLC6A14/NLRP3 axis.

Elaidic acid-induced intestinal barrier damage led to gut-liver axis derangement and triggered NLRP3 inflammasome in the liver of SD rats

Previous studies have shown that trans fatty acids(TFA) are associated with several chronic diseases,the gut microbiota is directly influenced by dietary components and linked to chronic diseases.Our research investigated the effects of elaidic acid(EA),a typical TFA,on the gut microbiota to understand the underlying mechanisms of TFA-related chronic diseases.16S rDNA gene sequencing on faecal samples from Sprague-Dawley rats were performed to explore the composition change of the gut microbiota by EA gavage for 4 weeks.The results showed that the intake of EA increased the abundance of well-documented harmful bacteria,such as Proteobacteria,Anaerotruncus,Oscillibacter and Desulfovibrionaceae.Plus,EA induced translocation of lipopolysaccharides(LPS) and the above pathogenic bacteria,disrupted the intestinal barrier,led to gut-liver axis derangement and TLR4 pathway activation in the liver.Overall,EA induced intestinal barrier damage and regulated TLR4-MyD88-NF-κB/MAPK pathways in the liver of SD rats,leading to the activation of NLRP3 inflammasome and inflammatory liver damage.

Lactobacillus rhamnosus GR-1 attenuates foodborne Bacillus cereus-induced NLRP3 inflammasome activity in bovine mammary epithelial cells by protecting intercellular tight junctions

Background:Bacillus cereus is an important pathogen that causes human food poisoning,specifically diarrhea and vomiting.B.cereus can also induce mastitis in dairy cows and has a strong survival ability in milk,as it cannot be inactivated by high-temperature short-time pasteurization.Therefore,B.cereus can enter the market through pasteurized milk and other dairy products,imposing enormous hidden dangers on food safety and human health.Results:In this study,B.cereus 2101(BC)was isolated from milk samples of cows with mastitis.BC grew rapidly with strong hemolysis,making it difficult to prevent mastitis and ensure food security.MAC-T cells were treated with BC and/or Lactobacillus rhamnosus GR-1(LGR-1).Pretreatment with LGR-1 protected the integrity of tight junctions and the expression of zonula occludens-1(ZO-1)and occludin destroyed by BC.Furthermore,LGR-1 pretreatment reduced the expression of NOD-like receptor family member pyrin domain-containing protein 3(NLRP3),caspase recruitment and activation domain(ASC),Caspase-1 p20,gasdermin D(GSDMD)p30,inflammatory factors(interleukin(IL)-1βand IL-18),and cell death induced by BC.Moreover,LGR-1 pretreatment reduced NLRP3 inflammasome activity and increased expressions of ZO-1 and occludin induced by lipopolysaccharides(LPS)+ATP stimulation.MAC-T cells were transfected with NLRP3 si RNA or MCC950 and/or treated with BC and/or LGR-1.NLRP3-si RNA transfection and MCC950 attenuated BC-induced NLRP3 inflammasome activity.Expression of inflammatory cytokines and cell death suggested that the inflammatory pathway might play an important role in the induction of the NLRP3 inflammasome by BC and the protection of LGR-1.Conclusions:These results suggest that LGR-1 might be a probiotic alternative to antibiotics and could be administered to prevent mastitis in dairy cows,thus ensuring food security.

The Alzheimer's disease-associated gene TREML2 modulates inflammation by regulating microglia polarization and NLRP3 inflammasome activation

Triggering receptor expressed on myeloid cells-like 2(TREML2)is a newly identified susceptibility gene for Alzheimer's disease(AD).It encodes a microglial inflammation-associated receptor.To date,the potential role of mic roglial TREML2 in neuroinflammation in the context of AD remains unclear.In this study,APP/PS1 mice were used to investigate the dynamic changes of TREML2 levels in brain during AD progression.In addition,lipopolysaccharide(LPS)stimulation of primary microglia as well as a lentivirus-mediated TREML2 overexpression and knockdown were employed to explore the role of TREML2 in neuroinflammation in the context of AD.Our res ults show that TREML2 levels gradually increased in the brains of AP P/PS1 mice during disease progression.LPS stimulation of primary microglia led to the release of inflammato ry cytokines including interleukin-1β,inte rleukin-6,and tumor necrosis factor-a in the culture medium.The LPS-induced mic roglial release of inflammatory cytokines was enhanced by TREML2 overexpression and was attenuated by TREML2 knoc kdown.LPS increased the levels of mic roglial M1-type polarization marker inducible nitric oxide synthase.This effect was enhanced by TREML2 overexpression and ameliorated by TREML2 knockdown.Furthermore,the levels of microglial M2-type polarization markers CD206 and ARG1 in the primary microglia were reduced by TREML2 overexpression and elevated by TREML2 knockdown.LPS stimulation increased the levels of NLRP3 in primary microglia.The LPS-induced increase in NLRP3 was further elevated by TREML2 overexpression and alleviated by TREML2 knockdown.In summary,this study provides the first evidence that TREML2 modulates inflammation by regulating microglial polarization and NLRP3 inflammasome activation.These findings reveal the mechanisms by which TREML2 regulates microglial inflammation and suggest that TREML2 inhibition may represent a novel therapeutic strategy for AD.

Vav1 promotes inflammation and neuronal apoptosis in cerebral ischemia/reperfusion injury by upregulating microglial and NLRP3 inflammasome activation

Microglia,which are the resident macrophages of the central nervous system,are an important part of the inflammatory response that occurs after cerebral ischemia.Vav guanine nucleotide exchange factor 1(Vav1) is a guanine nucleotide exchange factor that is related to microglial activation.However,how Vav1 participates in the inflammato ry response after cerebral ischemia/reperfusion inj ury remains unclea r.In this study,we subjected rats to occlusion and repe rfusion of the middle cerebral artery and subjected the BV-2 mic roglia cell line to oxygen-glucose deprivatio n/reoxygenation to mimic cerebral ischemia/repe rfusion in vivo and in vitro,respectively.We found that Vav1 levels were increased in the brain tissue of rats subjected to occlusion and reperfusion of the middle cerebral arte ry and in BV-2 cells subjected to oxygen-glucose deprivation/reoxygenation.Silencing Vav1 reduced the cerebral infarct volume and brain water content,inhibited neuronal loss and apoptosis in the ischemic penumbra,and im p roved neurological function in rats subjected to occlusion and repe rfusion of the middle cerebral artery.Further analysis showed that Vav1 was almost exclusively localized to microglia and that Vav1 downregulation inhibited microglial activation and the NOD-like receptor pyrin 3(NLRP3) inflammasome in the ischemic penumbra,as well as the expression of inflammato ry facto rs.In addition,Vov1 knoc kdown decreased the inflammatory response exhibited by BV-2 cells after oxygen-glucose deprivation/reoxyge nation.Taken together,these findings show that silencing Vav1 attenuates inflammation and neuronal apoptosis in rats subjected to cerebral ischemia/repe rfusion through inhibiting the activation of mic roglia and NLRP3 inflammasome.

Ginsenoside Rk2, a dehydroprotopanaxadiol saponin, alleviates alcoholic liver disease via regulating NLRP3 and NLRP6 inflammasome signaling pathways in mice

Heavy alcohol consumption results in alcoholic liver disease(ALD)with inadequate therapeutic options.Here,we first report the potential beneficial effects of ginsenoside Rk2(Rk2),a rare dehydroprotopanaxadiol saponin isolated from streamed ginseng,against alcoholic liver injury in mice.Chronic-plus-single-binge ethanol feeding caused severe liver injury,as manifested by significantly elevated serum aminotransferase levels,hepatic histological changes,increased lipid accumulation,oxidative stress,and inflammation in the liver.These deleterious effects were alleviated by the treatment with Rk2(5 and 30 mg/kg).Acting as an nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3(NLRP3)inhibitor,Rk2 ameliorates alcohol-induced liver inflammation by inhibiting NLRP3 inflammasome signaling in the liver.Meanwhile,the treatment with Rk2 alleviated the alcohol-induced intestinal barrier dysfunction via enhancing NLRP6 inflammasome in the intestine.Our findings indicate that Rk2 is a promising agent for the prevention and treatment of ALD and other NLPR3-driven diseases.

Glycogen Synthase Kinase-3β,NLRP3 Inflammasome,and Alzheimer's Disease

Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. Because of the progressive neurodegeneration, individual cognitive and behavioral functions are impaired, affecting the quality of life of millions of people. Although the exact pathogenesis of AD has not been fully elucidated, amyloid plaques, neurofibrillary tangles (NFTs), and sustaining neuroinflammation dominate its characteristics. As one of the major tau kinases leading to hyperphosphorylation and aggregation of tau, glycogen synthase kinase-3β (GSK-3β) has been drawing great attention in various AD studies. Another research focus of AD in recent years is the inflammasome, a multiprotein complex acting as a regulator in immunological reactions to exogenous and endogenous danger signals, of which the Nod-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome has been studied mostly in AD and proven to play a significant role in AD development by its activation and downstream effects such as caspase-1 maturation and interleukin (IL)-1β release. Studies have shown that the NLRP3 inflammasome is activated in a GSK-3β-dependent way and that inhibition of the NLRP3 inflammasome downregulates GSK-3β, suggesting that these two important proteins are closely related. This article reviews the respective roles of GSK-3β and the NLRP3 inflammasome in AD as well as their relationship and interaction.

Research Progress and Ideas on the Anti-liver Fibrosis Effect of Ethnic Medicine Plumbagin Based on microRNAs/TLR4/NF-κB and NLRP3 Inflammasome Activation

The core of hepatic fibrosis is the activation of hepatic stellate cells.Through the lipopolysaccharide/TLR4/MyD88/NF-κB signal transduction pathway,the inflammatory response in the liver is directly enhanced,and then returns to promote the activation of hepatic stellate cells.And TLR4/MyD88/NF-κB signaling pathway can directly regulate the activation of NLRP3 inflammasome and is an important pathway for activating hepatic stellate cells.TLR4/MyD88/NF-κB/NLRP3 inflammasome pathway is regulated by upstream microRNAs.These miRNAs can significantly regulate the inflammatory response of the liver and the activation behavior of hepatic stellate cells,affecting the formation of liver fibrosis.Previous studies have found that the active ingredient of Guangxi specialty ethnic medicine,plumbagin,has a definite anti liver fibrosis effect,but its mechanism of action is not clear.This paper provides a review of the research progress on the above issues,and further research ideas have been derived from this,stating that"the anti liver fibrosis effect of plumbagin is achieved by regulating miRNA/TLR4/MyD88/NF-κB inflammatory pathway and activating downstream NLRP3 inflammasome".

Mechanism of Qishen Decoction inhibition of macrophage M1 type polarization by targeting TGR5-mediated NLRP3 inflammasome

Objective:To observe the effect of Qishen decoction on TGR5-mediated activation of NLRP3 inflammasome,so as to clarify the molecular mechanism of its inhibition of macrophage M1-type polarisation to ameliorate non-alcoholic steatohepatitis;Methods:Mouse macrophage cell line RAW264.7 was randomly divided into a control group,model group,Qishen decoction group,TGR5 agonist group and Qishen decoction+TGR5 agonist group.Except for the control group,the remaining groups were constructed the macrophage NLRP3 activation model by palmitic acid induction,and the corresponding drugs were given to intervene.ELISA was used to detect the levels of TNF-α,IL-6,IL-1βand CXCL2 in macrophage supernatants,flow cytometry was used to detect the expression levels of macrophage polarisation marker molecules CD86 and iNOS,and Western blot was used to detect the expression of the TGR5/STAT1/STAT6 signaling pathway and the expression of NLRP3 inflammasome-associated proteins,respectively.Results:Compared with the control group,the contents of macrophages TNF-α,IL-6,IL-1β,CXCL2 and the proportion of macrophages with positive expression of CD86 and iNOS were significantly increased in the model group,and the differences were all statistically significant(P<0.01).Compared with the model group,the contents of TNF-α,IL-6,IL-1β,CXCL2 and the proportion of macrophages with positive expression of CD86 and iNOS were significantly decreased in the Qishen decoction group,and the differences were all statistically significant(P<0.01).In addition,the expression of NLRP3 and Pro-IL-1βproteins in the macrophage lysate and the expression of Caspase-1 p10,Caspase-1 p20 and IL-1βp17 proteins in the cell supernatant of the model group were significantly increased when compared with the control group,and the differences were all statistically significant(P<0.01).Compared with the model group,the expression of NLRP3 and Pro-IL-1βproteins in macrophage lysate and the expression of Caspase-1 p10,Caspase-1 p20 and IL-1βp17 proteins in cell supernatant of the Qishen decoction were significantly reduced,and the differences were all statistically significant(P<0.01);Conclusion:Qishen decoction can inhibit the activation of NLRP3 inflammasome in macrophages by inhibiting the TGR5/STAT1/STAT6 signaling pathway,thereby inhibiting macrophage M1 polarization and improving inflammatory response.

Effect of"Fuzheng Qingretonglin"decoction on complex urinary tract infection in rats by regulating NLRP3 inflammasome pathway

Obiective:To investigate whether"Fuzheng Qingretonglin"decoction can reduce urinary tract damage caused by complex urinary tract infection caused by drug resistant Escherichia coli by regulating Nod-like receptor pyrin domain3 inflammasome,and to explore the feasibility of this decoction combined with levofloxacin in the treatment of complex urinary tract infection caused by drug resistant bacteria.Methods:SD rats were divided into five groups:sham group,model group,levofloxacin group(Lev group),levofloxacin+Fuzheng Qingre Tonglin decoction group(FZ+lev group),and Fuzheng Qingre Tonglin decoction group(FZQRTL group).After the experiment,urine was taken for bacterial culture to determine the urinary tract infection of rats in each group;HE staining was used to observe the pathological changes of kidney and bladder tissues in rats;The expression of NLRP3 in kidney and bladder tissues was detected by immunohistochemistry;The expression of IL-1βand IL-18 in serum of rats was detected by ELISA;The expressions of NLRP3,ASC and Caspase-1 were detected by Western blotting.Results:The positive rate of urine bacteria culture in the sham group was 0%,the positive rate of urine bacteria culture in the model group was 100%;and the positive rate of urine bacteria culture in the FZ+lev group was 37.50%,which was statistically different from that in the model group(P<0.05).A large number of inflammatory cells were observed in the kidney and bladder tissues of the model group by HE staining,while the number of inflammatory cells in the kidney and bladder tissues of the Lev group and FZQRTL group was significantly reduced compared with that of the model group.The FZ+lev group in the number and structure of inflammatory cells in kidney and bladder were similar to the sham group.The NLRP3 immunohistochemistry of kidney and bladder tissue in FZ+lev groups and FZQRTL groups was significantly different from that in model group(P<0.001).The levels of IL-1βand IL-18 in serum of Lev group,FZQRTL group and FZ+lev group were significantly decreased by ELISA compared with model group(P<0.001).The levels of IL-1βand IL-18 in the FZ+lev groups were significantly lower than in the Lev group and FZQRTL group,and the differences were statistically significant(P<0.05).The protein expressions of NLRP3,ASC and Caspase-1 in the Lev group,FZQRTL group and FZ+lev group were significantly lower than those in the model group(P<0.001).The protein expressions of NLRP3,ASC and Caspase-1 in the FZ+lev groups were significantly lower than in the Lev group and FZQRTL group,and the differences were statistically significant(P<0.05).Conclusions:"Fuzheng Qingretonglin"decoction may have a protective effect on the kidney and bladder of rats with complex urinary tract infection caused by drug-resistant Escherichia coli by inhibiting the activation of NLRP3 inflammatory bodies,and TCM combined with levofloxacin has a better therapeutic effect than TCM or levofloxacin alone.

Mechanism of Sanshi decoction in the treatment of gouty arthritis by NLRP3 inflammasome

Objective:To observe the effect of Sanshi decoction on P2X7R/PKR pathway-mediated activation of macrophage NLRP3 inflammasome to elucidate the molecular mechanism of Sanshi decoction in the treatment of gouty arthritis.Methods:THP-1 macrophages were divided into control group,model group,low dose group,medium dose group,high dose group of Sanshi decoction and inhibitor group.The remaining groups were induced with monosodium urate crystals to establish a gouty arthritis cell model except the control group.Flow cytometry was used to detect macrophage ROS levels in each group,ELISA to detect MDA levels and SOD and GSH-PX activities in each group,and Western blot to detect P2X7R/PKR pathway and NLRP3 inflammasome-associated protein expression.We also used CCK-8 and flow cytometry to measure MH7A activity and apoptotic levels.Results:Compared with the control group,the ROS level,the content of MDA,the activities of SOD and GSH-PX were significantly increased,and the expression levels of NLRP3,full-length IL-1β,pro-IL-1β,full-length IL-18,pro-IL-18,full-length caspase-1,GSDMD-NT,P2X7R and p-PKR protein expression levels were significantly upregulated,and GSDMD-FL protein expression was significantly downregulated in the model group,and that the differences between them were statistically significant(P<0.05 and P<0.01).Compared with the model group,Sanshi decoction could reduce macrophage ROS levels,MDA content,SOD and GSHPX activities,and downregulate macrophage NLRP3,mature IL-1β,pro IL-1β,mature IL-18,pro IL-18,mature caspase-1,GSDMD-NT,P2X7R and p-PKR protein expression,and upregulate GSDMD-FL protein expression,with statistically significant differences(P<0.05 and P<0.01).In addition,MH7A activity was downregulated,and apoptosis level was upregulated in the model group in comparison with the control group,and differences were all significantly different(P<0.05).As compared to the model group,Sanshi decoction could significantly increase the activity of MH7A and inhibit the level of apoptosis,and that the differences between them were statistically significant(P<0.05 and P<0.01).Conclusion:Sanshi decoction can achieve the therapeutic effect of gouty arthritis by inhibiting P2X7R/PKR pathway activation,thus reducing the activation level of NLRP3.

Calpain-1 Mediated Mitochondria ROS/NLRP3 Inflammasome in Atherosclerosis

Calpains are calcium-activated cysteine proteases. There are two main isoforms of calpain that are ubiquitously expressed in tissues, calpain μ or calpain 1, which requires micromolar Ca2+ for activation, and calpain or 2, which requires millimolar Ca2+ for activation. The presence of other calpains is tissue specific. Atherosclerosis (AS) is an important risk factor for cerebral infarction, coronary heart disease and peripheral vascular disease. It was originally thought that AS was caused by impaired lipid metabolism. This research briefly reviewed Calpain Family, the structure and activation mechanism of calpain1, Calpains in the pathogenesis of atherosclerosis, NLRP3 structural characteristics and activation, ROS/NLRP3 inflammasome activation mechanism and ROS/NLRP3 inflammasome in atherosclerosis. The research showed that the Calpain-1 may play an important role in mitochondrial ROS/NLRP3 inflammasome in atherosclerosis.

Correlation Between NLRP3 Inflammasome and GP73 Levels and Hepatitis B Cirrhosis with Esophageal Varices Rupture

Objective:To investigate the correlation between NOD-like receptor family protein 3(NLRP3)inflammasome and Golgi protein 73(GP73)levels and hepatitis B cirrhosis with esophageal varices(EV)rupture.Methods:The subjects of this study were 145 patients with hepatitis B cirrhosis and varices who were treated in our hospital in recent years.Endoscopic examination was performed on the patients.The patients were divided into two groups according to whether there was EV rupture:rupture group and non-rupture group.The correlation between plasma NLRP3 and GP73 levels and hepatitis B cirrhosis with EV rupture was analyzed.Results:Through observation,comparing the levels of NLRP3 and GP73 between the two groups,the levels of NLRP3 and GP73 were significantly higher in the rupture group than in the non-rupture group(P<0.05).Logistic regression analysis showed that NLRP3 and GP73 levels and Child-Pugh classification were related risk factors of hepatitis B cirrhosis with EV rupture.Conclusion:NLRP3 inflammasome and GP73 levels are closely related to hepatitis B cirrhosis with EV rupture.The corresponding evaluation aids in predicting EV rupture and bleeding in patients with hepatitis B cirrhosis.

Mechanisms of renal interstitial fibrosis: cross-talk between mitophagy and NLRP3 inflammasome

Renal interstitial fibrosis(RIF)is the main pathological basis leading to end-stage renal disease,and is closely related to the prognosis of patients with kidney disease.Increasing evidence as shown that mitophagy and NLRP3 inflammasome play important roles in the pathogenesis of RIF.Studies suggest that inhibiting NLRP3 inflammasome by activating mitophagy can prevent and alleviate RIF.This review summarizes role played by cross-talk between mitophagy and NLRP3 inflammasome in promoting RIF,so as to offer new perspectives on more effective slow the progression of renal diseases and fibrosis prevention.

NLRP3/1-mediated pyroptosis:beneficial clues for the development of novel therapies for Alzheimer’s disease

The inflammasome is a multiprotein complex involved in innate immunity that mediates the inflammatory response leading to pyroptosis,which is a lytic,inflammatory form of cell death.There is accumulating evidence that nucleotide-binding domain and leucine-rich repeat pyrin domain containing 3(NLRP3)inflammasome-mediated microglial pyroptosis and NLRP1 inflammasome-mediated neuronal pyroptosis in the brain are closely associated with the pathogenesis of Alzheimer’s disease.In this review,we summarize the possible pathogenic mechanisms of Alzheimer’s disease,focusing on neuroinflammation.We also describe the structures of NLRP3 and NLRP1 and the role their activation plays in Alzheimer’s disease.Finally,we examine the neuroprotective activity of small-molecule inhibitors,endogenous inhibitor proteins,microRNAs,and natural bioactive molecules that target NLRP3 and NLRP1,based on the rationale that inhibiting NLRP3 and NLRP1 inflammasome-mediated pyroptosis can be an effective therapeutic strategy for Alzheimer’s disease.

Membrane vesicles derived from Streptococcus suis serotype 2 induce cell pyroptosis in endothelial cells via the NLRP3/Caspase-1/GSDMD pathway

Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.

Role of NLRP3 inflammasome in inflammatory bowel diseases

Inflammasomes are multiprotein intracellular complexes which are responsible for the activation of inflammatory responses. Among various subtypes of inflammasomes, NLRP3 has been a subject of intensive investigation. NLRP3 is considered to be a sensor of microbial and other danger signals and plays a crucial role in mucosal immune responses, promoting the maturation of proinflammatory cytokines interleukin 1β(IL-1β) and IL-18. NLRP3 inflammasome has been associated with a variety of inflammatory and autoimmune conditions, including inflammatory bowel diseases(IBD). The role of NLRP3 in IBD is not yet fully elucidated as it seems to demonstrate both pathogenic and protective effects. Studies have shown a relationship between genetic variants and mutations in NLRP3 gene with IBD pathogenesis. A complex interaction between the NLRP3 inflammasome and the mucosal immune response has been reported. Activation of the inflammasome is a key function mediated by the innate immune response and in parallel the signaling through IL-1β and IL-18 is implicated in adaptive immunity. Further research is needed to delineate the precise mechanisms of NLRP3 function in regulating immune responses. Targeting NLRP3 inflammasome and its downstream signaling will provide new insights into the development of future therapeutic strategies.

Hypoxic preconditioning reduces NLRP3 inflammasome expression and protects against cerebral ischemia/reperfusion injury

Hypoxic preconditioning can protect against cerebral ischemia/reperfusion injury. However, the underlying mechanisms that mediate this effect are not completely clear. In this study, mice were pretreated with continuous, intermittent hypoxic preconditioning;1 hour later, cerebral ischemia/reperfusion models were generated by middle cerebral artery occlusion and reperfusion. Compared with control mice, mice with cerebral ischemia/reperfusion injury showed increased Bederson neurological function scores, significantly increased cerebral infarction volume, obvious pathological damage to the hippocampus, significantly increased apoptosis;upregulated interleukin-1β, interleukin-6, and interleukin-8 levels in brain tissue;and increased expression levels of NOD-like receptor family pyrin domain containing 3(NLRP3), NLRP inflammasome-related protein caspase-1, and gasdermin D. However, hypoxic preconditioning significantly inhibited the above phenomena. Taken together, these data suggest that hypoxic preconditioning mitigates cerebral ischemia/reperfusion injury in mice by reducing NLRP3 inflammasome expression. This study was approved by the Medical Ethics Committee of the Fourth Hospital of Baotou, China(approval No. DWLL2019001) in November 2019.