Circulating perturbation of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is associated to cardiac remodeling and NLRP3 inflammasome in cardiovascular patients with insulin resistance risk.

Lipidome perturbation occurring during meta-inflammation is associated to left ventricle (LV) remodeling though the activation of the NLRP3 inflammasome, a key regulator of chronic inflammation in obesity-related disorders. Little is known about phosphatidylcholine (PC) and phosphatidylethanolamine (PE) as DAMP-induced NLRP3 inflammasome. Our study is aimed to evaluate if a systemic reduction of PC/PE molar ratio can affect NLRP3 plasma levels in cardiovascular disease (CVD) patients with insulin resistance (IR) risk. Forty patients from IRCCS Policlinico San Donato were enrolled, and their blood samples were drawn before heart surgery. LV geometry measurements were evaluated by echocardiography and clinical data associated to IR risk were collected. PC and PE were quantified by ESI-MS/MS. Circulating NLRP3 was quantified by an ELISA assay. Our results have shown that CVD patients with IR risk presented systemic lipid impairment of PC and PE species and their ratio in plasma was inversely associated to NLRP3 levels. Interestingly, CVD patients with IR risk presented LV changes directly associated to increased levels of NLRP3 and a decrease in PC/PE ratio in plasma, highlighting the systemic effect of meta-inflammation in cardiac response. In summary, PC and PE can be considered bioactive mediators associated to both the NLRP3 and LV changes in CVD patients with IR risk.

Tanshinone IIA Alleviates Early Brain Injury after Subarachnoid Hemorrhage in Rats by Inhibiting the Activation of NF-κB/NLRP3 Inflammasome.

The abnormal activation of the nuclear factor-kappa B (NF-κB)/nod-like receptor family-pyrin domain-containing 3 (NLRP3) signaling pathway is closely related to early brain injury after subarachnoid hemorrhage (SAH). Targeting the NLRP3-inflammasome has been considered an efficient therapy for the local inflammatory response after SAH. Tanshinone IIA (Tan IIA), a major component extracted from Salvia miltiorrhiza, has been reported to have anti-inflammatory effects. The aim of this study was to investigate the effect and mechanism of Tan IIA on early brain injury after SAH. In vivo SAH injury was established by endovascular perforation technique in Sprague-Dawley rats. Limb-placement test and corner turning test were used to measure the behavior. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining, hematoxylin-eosin (H&E) staining, and immunofluorescence were used to evaluate the nerve damage. Real-time RT quantitative PCR (RT-qPCR) was used to quantify the levels of inflammatory factors. Western blot was performed for the activation of the NF-κB/NLRP3 pathway. An in vitro SAH model was used to validate the conclusion. We found that the neurobehavioral impairment and cerebral edema in SAH model rats given Tan IIA were alleviated. Further study demonstrated that Tan IIA could inhibit SAH-secondary neuronal apoptosis around hematoma and alleviate brain injury. Tan IIA down-regulated the expression of interleukin-6 (IL)-6, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor (TNF)-α, and inhibited the activation of NF-κB. And the overexpression of pro-inflammatory factors NLRP3, IL-1ß, and IL-18 induced after SAH was also reversed by Tan IIA. In conclusions, Tan IIA could inhibit the NF-κB/NLRP3 inflammasome activation to protect and ameliorate SAH-followed early brain injury, and may be a preventive and therapeutic strategy against SAH.

Vitamin D Mitigates Hepatic Fat Accumulation and Inflammation and Increases SIRT1/AMPK Expression in AML-12 Hepatocytes.

Emerging evidence has demonstrated a strong correlation between vitamin D status and fatty liver disease. Aberrant hepatic fat infiltration contributes to oxidant overproduction, promoting metabolic dysfunction, and inflammatory responses. Vitamin D supplementation might be a good strategy for reducing hepatic lipid accumulation and inflammation in non-alcoholic fatty liver disease and its associated diseases. This study aimed to investigate the role of the most biologically active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)2D), in hepatic fat accumulation and inflammation in palmitic acid (PA)-treated AML-12 hepatocytes. The results indicated that treatment with 1,25(OH)2D significantly decreased triglyceride contents, lipid peroxidation, and cellular damage. In addition, mRNA levels of apoptosis-associated speck-like CARD-domain protein (ASC), thioredoxin-interacting protein (TXNIP), NOD-like receptor family pyrin domain-containing 3 (NLRP3), and interleukin-1ß (IL-1ß) involved in the NLRP3 inflammasome accompanied by caspase-1 activity and IL-1ß expression were significantly suppressed by 1,25(OH)2D in PA-treated hepatocytes. Moreover, upon PA exposure, 1,25(OH)2D-incubated AML-12 hepatocytes showed higher sirtulin 1 (SIRT1) expression and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. A SIRT1 inhibitor alleviated the beneficial effects of 1,25(OH)2D on PA-induced hepatic fat deposition, IL-1ß expression, and caspase-1 activity. These results suggest that the favorable effects of 1,25(OH)2D on hepatic fat accumulation and inflammation may be, at least in part, associated with the SIRT1.

Possible roles of anti-type II collagen antibody and innate immunity in the development and progression of diabetic retinopathy.

The pathogenesis of both diabetic retinopathy (DR) and rheumatoid arthritis (RA) has recently been considered to involve autoimmunity. Serum and synovial fluid levels of anti-type II collagen antibodies increase early after the onset of RA, thus inducing immune responses and subsequent hydrarthrosis and angiogenesis, which resemble diabetic macular edema and proliferative DR (PDR), respectively. We previously reported that DR is also associated with increased serum levels of anti-type II collagen antibodies. Retinal hypoxia in DR may induce pericytes to express type II collagen, resulting in autoantibody production against type II collagen. As the result of blood-retinal barrier disruption, anti-type II collagen antibodies in the serum come into contact with type II collagen around the retinal vessels. A continued loss of pericytes and type II collagen around the retinal vessels may result in a shift of the immune reaction site from the retina to the vitreous. It has been reported that anti-inflammatory M2 macrophages increased in the vitreous of PDR patients, accompanied by the activation of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity. M2 macrophages promote angiogenesis and fibrosis, which might be exacerbated and prolonged by dysregulated innate immunity.

Interaction between autophagy and the NLRP3 inflammasome.

Autophagy, a metabolic pathway that plays an important role in maintaining the dynamic balance of cells, has two types, i.e. non-selective autophagy and selective autophagy. The role of non-selective autophagy is primarily to allow cells to circulate nutrients in an energy-limited environment, while selective autophagy primarily cleans up the organelles inside the cells to maintain the cell structure. The NLRP3 inflammasome is an innate immune response produced by the organism that can promote the secretion of interleukin-1ß and interleukin-18 through caspase-1 activation and resist the damage of some pathogens. However, when the NLRP3 inflammasome is overactivated, it can cause various inflammatory diseases, such as inflammatory liver disease and inflammatory bowel disease. Many previous studies have shown that autophagy can inhibit the NLRP3 inflammasome, while in recent years, new studies have found that autophagy can also promote the NLRP3 inflammasome in some cases, and the NLRP3 inflammasome can, in turn, affect autophagy. In this review, the interaction between autophagy and the NLRP3 inflammasome is explored, and then the application of this interaction in disease treatment is discussed.

Functional Characterization of an Arylsulfonamide-Based Small-Molecule Inhibitor of the NLRP3 Inflammasome.

Considerable evidence indicates that the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome plays key roles in human pathophysiology, suggesting it as a potential drug target. Currently, studies have yet to develop compounds that are promising therapeutics in the clinic by targeting the NLRP3 inflammasome. Herein, we aim to further biologically characterize a previously identified small-molecule inhibitor of the NLRP3 inflammasome from our group, YM-I-26, to confirm its functional activities. We showed that YM-I-26 is highly selective toward the NLRP3 inflammasome and binds to NLRP3 directly. A systemic analysis revealed YM-I-26 with inflammation-related and immunomodulatory activities by the Eurofins BioMAP Diversity PLUS panel. In addition, studies using the mouse microglia BV2 cell model demonstrated that YM-I-26 is not cytotoxic, improved the phagocytotic functions of BV2 cells toward beta-amyloid, and suppressed the production of cytokines of IL-1ß and IL-10 upon the activation of the NLRP3 inflammasome. Collectively, our studies support the functional activities of YM-I-26 as a NLRP3 inhibitor in physiologically relevant cell models, and warrant future studies of YM-I-26 and its analogs to advance the drug development as potential therapeutics.

Gegen Qinlian decoction ameliorates TNBS-induced ulcerative colitis by regulating Th2/Th1 and Tregs/Th17 cells balance, inhibiting NLRP3 inflammasome activation and reshaping gut microbiota.

ETHNOPHARMACOLOGICAL RELEVANCE: Chinese herbal medicine Gegen Qinlian Decoction (GQD) has been clinically shown to be an effective treatment of ulcerative colitis (UC) in China. However, the underlying mechanism of GQD's anti-ulcerative colitis properties and its effect on gut microbiota still deserve further exploration. AIM OF THE STUDY: This study observed the regulatory effects of GQD on Th2/Th1 and Tregs/Th17 cells balance, the NOD-like receptor family pyrin domain containing 3 (NLRP3) infammasome and gut microbiota in TNBS-induced UC in BALB/c mice. MATERIALS AND METHODS: 61 main chemical compounds in the GQD were determined by UPLC-Q-TOF/MS. The UC BALB/c model was established by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and GQD was orally administered at low and high dosages of 2.96 and 11.83 g/kg/day, respectively. The anti-inflammatory effects of GQD for ulcerative colitis were evaluated by survival rate, body weight, disease activity index (DAI) score, colonic weight and index, spleen index, hematoxylin-eosin (HE) staining and histopathological scores. Flow cytometry was used to detect the percentage of CD4, Th1, Th2, Th17 and Tregs cells. The levels of Th1-/Th2-/Th17-/Tregs-related inflammatory cytokines and additional proinflammatory cytokines (IL-1ß, IL-18) were detected by CBA, ELISA, and RT-PCR. The expressions of GATA3, T-bet, NLRP3, Caspase-1, IL-Iß, Occludin and Zonula occludens-1 (ZO-1) on colon tissues were detected by Western blot and RT-PCR. Transcriptome sequencing was performed using colon tissue and 16S rRNA gene sequencing was performed on intestinal contents. Fecal microbiota transplantation (FMT) was employed to assess the contribution of intestinal microbiota and its correlation with CD4 T cells and the NLRP3 inflammasome. RESULTS: GQD increased the survival rate of TNBS-induced UC in BALB/c mice, and significantly improved their body weight, DAI score, colonic weight and index, spleen index, and histological characteristics. The intestinal barrier dysfunction was repaired after GQD administration through promoting the expression of tight junction proteins (Occludin and ZO-1). GQD restored the balance of Th2/Th1 and Tregs/Th17 cells immune response of colitis mice, primarily inhibiting the increase in Th2/Th1 ratio and their transcription factor production (GATA3 and T-bet). Morever, GQD changed the secretion of Th1-/Th2-/Th17-/Tregs-related cytokines (IL-2, IL-12, IL-5, IL-13, IL-6, IL-10, and IL-17A) and reduced the expressions of IL-1ß, IL-18. Transcriptome results suggested that GQD could also remodel the immune inflammatory response of colitis by inhibiting NOD-like receptor signaling pathway, and Western blot, immunohistochemistry and RT-PCR further revealed that GQD exerted anti-inflammatory effects by inhibiting the NLRP3 inflammasome, such as down-regulating the expression of NLRP3, Caspase-1 and IL-1ß. More interestingly, GQD regulated gut microbiota dysbiosis, suppressed the overgrowth of conditional pathogenic gut bacteria like Helicobacter, Proteobacteria, and Mucispirillum, while the probiotic gut microbiota, such as Lactobacillus, Muribaculaceae, Ruminiclostridium_6, Akkermansia, and Ruminococcaceae_unclassified were increased. We further confirmed that GQD-treated gut microbiota was sufficient to relieve TNBS-induced colitis by FMT, involving the modulation of Th2/Th1 and Tregs/Th17 balance, inhibition of NLRP3 inflammasome activation, and enhancement of colonic barrier function. CONCLUSIONS: GQD might alleviate TNBS-induced UC via regulating Th2/Th1 and Tregs/Th17 cells Balance, inhibiting NLRP3 inflammasome and reshaping gut microbiota, which may provide a novel strategy for patients with colitis.

Inflammasomes during SARS-CoV-2 infection and development of their corresponding inhibitors.

Corona Virus Disease 2019 (COVID-19) continues to be a burden for human health since its outbreak in Wuhan, China in December 2019. Recently, the emergence of new variants of concerns (VOCs) is challenging for vaccines and drugs efficiency. In severe cases, SARS-CoV-2 provokes inappropriate hyperinflammatory immune responses leading to acute respiratory distress syndrome (ARDS) and even death. This process is regulated by inflammasomes which are activated after binding of the viral spike (S) protein to cellular angiotensin-converting enzyme 2 (ACE2) receptor and triggers innate immune responses. Therefore, the formation of "cytokines storm" leads to tissue damage and organ failure. NOD-like receptor family pyrin domain containing 3 (NLRP3) is the best studied inflammasome known to be activated during SARS-CoV-2 infection. However, some studies suggest that SARS-CoV-2 infection is associated with other inflammasomes as well; such as NLRP1, absent in melanoma-2 (AIM-2), caspase-4 and -8 which were mostly found during dsRNA virus or bacteria infection. Multiple inflammasome inhibitors that exist for other non-infectious diseases have the potential to be used to treat severe SARS-CoV-2 complications. Some of them have showed quite encouraging results during pre- and clinical trials. Nevertheless, further studies are in need for the understanding and targeting of SARS-Cov-2-induced inflammasomes; mostly an update of its role during the new VOCs infection is necessary. Hence, this review highlights all reported inflammasomes involved in SARS-CoV-2 infection and their potential inhibitors including NLRP3- and Gasdermin D (GSDMD)-inhibitors. Further strategies such as immunomodulators and siRNA are also discussed. As highly related to COVID-19 severe cases, developing inflammasome inhibitors holds a promise to treat severe COVID-19 syndrome effectively and reduce mortality.

Clinical application of serum NLRP3 on the diagnosis and prognosis of sepsis patients complicated with acute respiratory distress syndrome.

Introduction: Acute respiratory distress syndrome (ARDS) is a common complication of sepsis, which significantly increases the mortality rate. This work explored the diagnostic value of serum NOD-like receptor family pyrin domain containing 3 (NLRP3) concentration in patients with sepsis for ARDS, and the predictive value of serum NLRP3 concentration at the time of diagnosis for death 28 days after treatment. Methods: A total of 150 sepsis patients were included in this study, including age-matched two groups of patients, 75 patients with ARDS and 75 patients without ARDS. In addition, 60 age-matched healthy patients with physical examination were recruited in this study. Serum NLRP3 concentration was determined by enzyme-linked immunosorbent assay (ELISA). The diagnostic values of serum NLRP3 concentration for ARDS in sepsis patients were evaluated by receiver operating characteristics (ROC) analysis. Correlation of serum NLRP3 with APACHE II score and SOFA were performed by Spearman correlation analysis. Results: Pulmonary infection, APACHE II score and serum NLRP3 concentration were risk factors for patients with sepsis complicated with ARDS. ROC curve results showed that the specificity of serum NLRP3 concentration was 74.67%, the sensitivity was 76.00%, and the area under the curve (AUC) was 0.82 (p<0.001). APACHE II score and SOFA were significantly positively correlated with serum NLRP3 concentration. Baseline serum NLRP3 levels had significant predictive value for 28-day mortality in sepsis patients complicated with ARDS. Conclusion: Serum NLRP3 concentration has clinical value in the diagnosis of sepsis complicated with ARDS.

Bergenin inhibits palmitic acid-induced pancreatic ß-cell inflammatory death via regulating NLRP3 inflammasome activation.

Background: Bergenin, an active constituent of plants of the genus Bergenia, has been reported to have antidiabetic properties. This study investigated whether bergenin is beneficial for treating type 2 diabetes mellitus (T2DM) via regulating NOD-like receptor family-pyrin domain containing 3 (NLRP3) inflammasome. Methods: Two pancreatic ß-cell lines, INS-1 and MIN6, were treated with 1, 3, or 10 µM bergenin in the absence or presence of palmitic acid (PA). Cell Counting Kit (CCK)-8, flow cytometry, quantitative reverse transcription-polymerase chain reaction, western blotting, and immunofluorescent staining were performed. Results: Bergenin with concentrations of 1, 3, and 10 µM had no cytotoxicity in INS-1 and MIN6 cells. However, bergenin dose-dependently relieved PA-induced pancreatic ß­cell loss and apoptosis. Bergenin dose-dependently inhibited NLRP3 inflammasome-related inflammation, as observed by the downregulation of NLRP3, apoptosis associated speck like protein (ASC), cleaved caspase-1, and gasdermin-D (GSDMD)-N, as well as the decreased release of cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1ß, and IL-18. The NOD-like receptor signaling pathway was predicted to be a downstream signaling pathway regulated by bergenin. Autodock Vina software docked bergenin with NLRP3. The binding energy of interaction was -5.101 kcal/mol and the root-mean-square deviation (RMSD) score was 1.5901A. Treating pancreatic ß­cells with bergenin accelerated the degeneration of NLRP3. Furthermore, restoration of NLRP3 expression using plasmid transfection reversed the protective effects of bergenin on pancreatic ß-cells. Conclusions: Our data suggests that bergenin is a potential agent for treating T2DM through preventing NLRP3 inflammasome-related inflammation in pancreatic ß-cells.

Crosstalk Between RPE Cells and Choroidal Endothelial Cells via the ANXA1/FPR2/SHP2/NLRP3 Inflammasome/Pyroptosis Axis Promotes Choroidal Neovascularization.

One type of age-related macular degeneration (AMD), neovascular (nAMD), characterized by choroidal neovascularization (CNV), accounts for the majority of the severe central vision impairment associated with AMD. Endothelial cells (ECs) in direct contact with retinal pigment epithelial (RPE) cells are more prone to the pathological angiogenesis involved in CNV. Herein, we investigated the effect of crosstalk between RPE cells and choroidal endothelial cells (CECs) via the ANXA1/FPR2/NLRP3 inflammasome/pyroptosis axis on the development of choroidal neovascularization (CNV) in vitro and in vivo. ANXA1 expression and secretion from ARPE-19 cells were upregulated by hypoxia. FPR2 expression, especially on the plasma membrane, in HCECs was upregulated under hypoxic conditions. ANXA1 secreted from ARPE-19 cells inhibited NLRP3 inflammasome activation and NLRP3 inflammasome-mediated pyroptosis in HCECs by activating the FPR2/SHP2 axis. Moreover, ANXA1 secreted by ARPE-19 cells promoted behaviors of HCECs, including proliferation, migration, and tube formation, by activating the FPR2/SHP2 axis and inhibiting NLRP3 inflammasome-mediated pyroptosis. Inhibiting the upregulated ANXA1/FPR2/SHP2/NLRP3 inflammasome/pyroptosis axis decreased the volume of CNV. Our data suggest that the crosstalk between RPE cells and CECs via the ANXA1/FPR2/NLRP3 inflammasome/pyroptosis axis promotes CNV. This finding could identify a potential target for the prevention and treatment of CNV.

A narrative review of positive regulation of NLRP3 inflammasome in rheumatoid arthritis.

OBJECTIVE: This paper briefly reviews the pathological characteristics and regulatory mechanism of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and summarizes the relationship between it and rheumatoid arthritis (RA) as a means to improve its therapeutic potential and clinical application. BACKGROUND: RA is a systemic inflammatory disease with a high incidence rate. The early diagnosis and treatment of the disease is difficult, and the current treatment effect of most patients is not significant and accompanied by serious infection risk. Inflammation is an immune protective mechanism in the body. Inflammasome is an intracellular multi-body protein that stimulates the inflammatory response [inducing the release of pro-inflammatory cytokine interleukin (IL)-1ß and IL-18] and promotes the death of thermophiles. The NLRP3 inflammatory bodies are assembled from NLRP3, apoptosis-associated speck-like protein (ASC), and pro-caspase-1. Previous studies have enriched our understanding of the activation mechanism of NLRP3 inflammasome, and animal model data suggests that it plays an important role in autoimmune diseases, including RA. METHODS: Literatures about inflammation and RA were extensively reviewed to analyze and discuss. CONCLUSIONS: Especially, we focused on the role of NLRP3 inflammasome in the pathogenesis of RA and the potential of NLRP3 inflammasome or their derivatives in the treatment of RA, which enriched the treatment strategies of inflammatory diseases.

Salidroside inhibits NLRP3 inflammasome activation and apoptosis in microglia induced by cerebral ischemia/reperfusion injury by inhibiting the TLR4/NF-κB signaling pathway.

BACKGROUND: The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is an important mediator of neuroinflammatory responses that regulates inflammatory injury following cerebral ischemia and may be a potential target. Salidroside (Sal) has good anti-inflammatory effects; however, it remains unclear whether Sal can regulate NLRP3 inflammasome activation through the Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signaling pathway after cerebral ischemia to alleviate inflammatory injury. METHODS: We established an oxygen-glucose deprivation and reoxygenation (OGD/R) model of BV2 cells and a middle cerebral artery occlusion/reperfusion (MCAO/R) rat model. Cell Counting Kit-8 (CCK-8), flow cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay were used to detect the viability and apoptosis of BV2 cells. Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of inflammatory factors. 2,3,5-triphenyltetrazolium chloride (TTC) staining and modified Neurological Severity Score (mNSS) were used to detect cerebral infarction volume and neurological deficit in rats. Western blot, immunohistochemistry and immunofluorescence staining were used to detect the protein expression levels. RESULTS: Our results showed that Sal increased viability, inhibited lactate dehydrogenase (LDH) release, and reduced apoptosis in OGD/R-induced BV2 cells. Sal reduced the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-8. Following induction by OGD/R, BV2 cells exhibited NLRP3 inflammasome activation and increased protein levels of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, IL-1ß, and IL-18. Protein levels of key TLR4 signaling pathway elements, such as TLR4, myeloid differentiation primary response 88 (MyD88), and phosphorylated nuclear factor kappa B p65 (p-NF-κB p65)/NF-κB p65 were upregulated. Interestingly, it was revealed that Sal could reverse these changes. In addition, TAK242, a specific inhibitor of TLR4, had the same effect as Sal treatment on BV2 cells following induction by OGD/R. In the MCAO/R rat model, Sal was also observed to inhibit NLRP3 inflammasome activation in microglia, reduce cerebral infarction volume, and inhibit apoptosis. CONCLUSIONS: In summary, we found that Sal inhibited NLRP3 inflammasome activation and apoptosis in microglia induced by cerebral ischemia/reperfusion injury by inhibiting the TLR4/NF-κB signaling pathway, thus playing a protective role. Therefore, Sal may be a promising drug for the clinical treatment of ischemic stroke.

The SGLT2 inhibitor dapagliflozin attenuates the activity of ROS-NLRP3 inflammasome axis in steatohepatitis with diabetes mellitus.

BACKGROUND: Diabetes mellitus (DM) is considered as a risk factor for the progress of liver diseases. After tissue damage, there is the highest amplitude of ubiquitously sterile inflammatory response in the liver, resulting in a major clinical consequence concerning a high prevalence of steatohepatitis in DM patients. This study aimed to investigate the inhibitory efficacy of dapagliflozin (DAPA), a sodium glucose cotransporter-2 (SGLT2) inhibitor, on experimental steatohepatitis with DM. METHODS: DM-steatohepatitis model was established by dual intraperitoneal injection of streptozotocin (STZ) and feeding with the high-fat diet (HFD) in apolipoprotein E-deficient (ApoE-/-) mice (n=40). The mice were concurrently treated with DAPA (1 mg/kg/d) by gavage for 12 weeks. RESULTS: In ApoE-/- mice, dual HFD/STZ dramatically induced hepatic damage and inflammation as compared with HFD alone. DAPA treatment was effective to protect from hepatic damage and inflammation in dual HFD/STZ treated ApoE-/- mice. DAPA also significantly the probability decreased the blood glucose, hepatic lipid accumulation, liver steatosis, and fibrotic response in dual HFD/STZ treated ApoE-/- mice. Further mechanistic investigations indicated that the protection of DAPA on diabetic liver injury was associated with the suppressed production of hepatic reactive oxygen species (ROS) and malondialdehyde (MDA) and the inhibited activation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome. CONCLUSIONS: These data demonstrate the efficacy of DAPA for protecting liver damage, inflammation and steatosis from experimental steatohepatitis with DM, and indicate a possible involvement of the inhibited activity of ROS-NLRP3 inflammasome.

Extracellular mitochondrial DNA promote NLRP3 inflammasome activation and induce acute lung injury through TLR9 and NF-κB.

BACKGROUND: Extracellular mitochondrial DNA (mtDNA) was demonstrated to be capable of inducing pulmonary inflammation through TLR9 while its role in NLRP3 inflammation activation remains unknown. METHODS: C57BL/6 mice were challenged intratracheally with mtDNA. Pulmonary pathology, the NLRP3 and caspase-1 p20 in lung tissues were assayed. PMA-primed THP-1 macrophages were incubated with mtDNA in vitro and cell-free medium were concentrated to detect caspase-1 p20 subunit and NLRP3 by Western blotting. Additionally, IL-1ß, L-18, TNF-α and caspase-1 activity in culture were also analyzed by ELISA kits and activity assay kit. RESULTS: Intratracheal administration of mtDNA increased NLRP3 and caspase-1 p20 subunit in lung together with excessive inflammation and damage. Inhibition of caspase-1 substantially diminished mtDNA-induced lung injury and inflammation. Exposed to mtDNA in THP-1 macrophages resulted in significant up-regulation of NLRP3 and increased caspase-1 p20 subunit release in culture. It also led to significant increased transcripts of NLRP3, ASC, caspase-1 and release of IL-1ß, IL-18 and TNF-α in culture media. Futhermore, mtDNA exposure resulted in significant up-regulation of phosho -p38 MAPK and nucleus translocation of NF-κB. mtDNA-induced Transcripts of NLRP3 and ASC were inhibited by p38 siRNA inhibitor or NF-κB inhibitor. CONCLUSIONS: Extracellular mtDNA promote NLRP3 inflammasome activation, acute pulmonary inflammation and injury through TLR9, p38 MAPK and NF-κB pathways.