Protective role of irbesartan against cyclophosphamide-induced testicular damage in rats via up-regulating PPAR-γ signaling and ameliorating NF-κB/NLRP3/IL-18 inflammatory axis.

BACKGROUND: Cancer and its therapies can impact fertility in various ways, and therefore a growing number of cancer survivors face fertility as a significant concern. The cytotoxic alkylating agent cyclophosphamide (CP) is commonly used as an antineoplastic agent; unfortunately, its use is significantly associated with male infertility and damage to the reproductive system. AIM: The present study aimed to assess the possible beneficial effects of Irbesartan (IRB) in a rat model of CP-induced testicular toxicity. MAIN METHODS: The effects of treatment were assessed by measuring peroxisome proliferator-activated receptor gamma (PPAR-γ) expression via qRT-PCR, the immunohistochemical (IHC) assessment of apoptotic markers, NOD-like receptor protein 3 (NLRP3), and nuclear factor-κB (NF-κB), determination of the count and viability of epididymal sperm, oxidative stress markers via biochemical analysis, serum testosterone, caspase-1, and interleukin-18 (IL-18) levels via ELISA, histopathological assessment, and fibrosis by Masson's trichrome (MT) stain. KEY FINDINGS: There was a significant increase in malondialdehyde (MDA), caspase-1, and IL-18 contents, NF-κB, NLRP3, Bcl-2-associated X protein (Bax), caspase-3, and MT staining in testicular tissue after CP administration compared to the normal control group. Whereas reduced glutathione (GSH), superoxide dismutase (SOD), PPAR-γ expression, B-cell lymphoma-2 (Bcl-2) staining, serum testosterone, and the count and viability of epididymal sperm were decreased compared to the normal control group. The IRB treatment has reversed CP-induced testicular toxicity. SIGNIFICANCE: It is possible to conclude that IRB revealed a significant testicular protective effect against CP via antioxidant, anti-apoptotic, and anti-inflammatory effects.

GPR Expression in Intestinal Biopsies From SCT Patients Is Upregulated in GvHD and Is Suppressed by Broad-Spectrum Antibiotics.

Microbiota can exert immunomodulatory effects by short-chain fatty acids (SCFA) in experimental models of graft-versus-host disease (GvHD) after allogeneic hematopoietic stem cell transplantation (allo-SCT). Therefore we aimed to analyze the expression of SCFAs sensing G-protein coupled receptor GPR109A and GPR43 by quantitative PCR in 338 gastrointestinal (GI) biopsies obtained from 199 adult patients undergoing allo-SCT and assessed the interaction of GPR with FOXP3 expression and regulatory T cell infiltrates. GPR expression was strongly upregulated in patients with stage II-IV GvHD (p=0.000 for GPR109A, p=0.01 for GPR43) and at the onset of GvHD (p 0.000 for GPR109A, p=0.006 for GPR43) and correlated strongly with FOXP3 and NLRP3 expression. The use of broad-spectrum antibiotics (Abx) drastically suppressed GPR expression as well as FOXP3 expression in patients' gut biopsies (p=0.000 for GPRs, FOXP3 mRNA and FOXP3+ cellular infiltrates). Logistic regression analysis revealed treatment with Abx as an independent factor associated with GPR and FOXP3 loss. The upregulation of GPRs was evident only in the absence of Abx (p=0.001 for GPR109A, p=0.014 for GPR43) at GvHD onset. Thus, GPR expression seems to be upregulated in the presence of commensal bacteria and associates with infiltration of FOXP3+ T regs, suggesting a protective, regenerative immunomodulatory response. However, Abx, which has been shown to induce dysbiosis, interferes with this protective response.

A peptide derived from chaperonin 60.1, IRL201104, inhibits LPS-induced acute lung inflammation.

Chaperonin 60.1 (Cpn60.1) is a protein derived from Mycobacterium tuberculosis that has been shown, along with its peptide fragment IRL201104, to have beneficial effects in models of allergic inflammation. To further investigate the anti-inflammatory properties of Cpn60.1 and IRL201104, we have investigated these molecules in a model of nonallergic lung inflammation. Mice were treated with Cpn60.1 (0.5-5,000 ng/kg) or IRL201104 (0.00025-2.5 ng/kg), immediately before intranasal instillation of bacterial lipopolysaccharide (LPS). Cytokine levels and cell numbers in mouse bronchoalveolar lavage (BAL) fluid were measured 4 h after LPS administration. In some experiments, mice were depleted of lung-resident phagocytes. Cells from BAL fluid were analyzed for inflammasome function. Human umbilical vein endothelial cells (HUVECs) were analyzed for adhesion molecule expression. Human neutrophils were analyzed for integrin expression, chemotaxis, and cell polarization. Cpn60.1 and IRL201104 significantly inhibited neutrophil migration into the airways, independently of route of administration. This effect of the peptide was absent in TLR4 and annexin A1 knockout mice. Intravital microscopy revealed that IRL201104 reduced leukocyte adhesion and migration into inflamed tissues. However, IRL201104 did not significantly affect adhesion molecule expression in HUVECs or integrin expression, chemotaxis, or polarization of human neutrophils at the studied concentrations. In phagocyte-depleted animals, the anti-inflammatory effect of IRL201104 was not significant. IRL201104 significantly reduced IL-1ß and NLRP3 expression and increased A20 expression in BAL cells. This study shows that Cpn60.1 and IRL201104 potently inhibit LPS-induced neutrophil infiltration in mouse lungs by a mechanism dependent on tissue-resident phagocytes and to a much lesser extent, the proresolving factor annexin A1.

The Severity of CVB3-Induced Myocarditis Can Be Improved by Blocking the Orchestration of NLRP3 and Th17 in Balb/c Mice.

BACKGROUND: The functional characteristics of NLRP3 in the pathogenesis of coxsackievirus B3- (CVB3-) induced viral myocarditis (VMC) have not been fully elucidated, and the targeted therapeutic effect of NLRP3 or its related pathway in VMC has not been reported. METHOD: In this work, the change patterns of NLRP3- and Th17-related factors were detected during the pathological process of CVB3-induced VMC in Balb/c mice. The correlation between NLRP3 and Th17 cells during the VMC process was analyzed by Spearman test. The coculture system of spleen CD4+ T and bone marrow CD11c+ DC cells was set to explore the orchestration of NLRP3 and Th17 in the pathological development of VMC in vitro. Anti-IL-1ß antibody or NLRP3-/- Balb/c were used to block the NLRP3 pathway indirectly and directly to analyze the NLRP3-targeting therapeutic value. RESULTS: The change patterns of NLRP3- and Th17-related molecules in the whole pathological process of mouse CVB3-induced VMC were described. Through Spearman correlation analysis, it was confirmed that there was a close correlation between NLRP3 and Th17 cells in the whole pathological process of VMC. And the interaction mode between NLRP3 and Th17 was preliminarily explored in the cell experiment in vitro. Under the intervention of an anti-IL-1ß antibody or NLRP3 knockout, the survival rate of the intervention group was significantly improved, the degree of myocardial inflammation and fibrosis was significantly alleviated, and the content of myocardial IL-17 and spleen Th17 was also significantly decreased. CONCLUSION: Our findings demonstrated a key role of the NLRP3 inflammasome and its close relationship with Th17 in the pathological progression of CVB3-induced VMC and suggested a possible positive feedback-like mutual regulation mechanism between the NLRP3 inflammasome and Th17 in vitro and in the early stage of CVB3 infection. Taking NLRP3 as a new starting point, it provides a new target and idea for the prevention and treatment of CVB3-induced VMC.

VDAC1 regulates mitophagy in NLRP3 inflammasome activation in retinal capillary endothelial cells under high-glucose conditions.

Diabetic retinopathy (DR) has been considered to involve mitochondrial alterations and be related to the nucleotide-binding oligomerization domain-like receptors 3 (NLRP3) inflammasome activation. The voltage-dependent anion channel 1 (VDAC1) protein is one of the key proteins that regulates the metabolic and energetic functions of the mitochondria. To explore the involvement of VDAC1 in mitophagy regulation of NLRP3 inflammasome activation under high-glucose (HG) conditions, this study examined expressions of VDAC1, mitochondrial function and mitophagy-related proteins, and NLRP3 inflammasome-related proteins in human retinal capillary endothelial cells (HRCECs) cultured with 30 mM of glucose in the presence or absence of mitophagy inhibitor (Mdivi-1) using Western blot. Mitochondrial membrane potential and mitochondrial reactive oxygen species (mtROS) were detected using flow cytometry. GFP-tagged pAdTrack-VDAC1 adenovirus was used to overexpress VDAC1. Cell biological behaviors, including proliferation, migration, tubule formation, and apoptosis, were also observed. Our results showed that when compared to the normal glucose and high mannitol groups, increased amounts of mitochondrial fragments, reduced mitochondrial membrane potential, increased expression of mitochondrial fission protein Drp 1, decreased expression of mitochondrial fusion protein Mfn 2, accumulation of mtROS, and activation of the NLRP3 inflammasome were observed in the HG group. Meanwhile, HG markedly reduced the protein expressions of PINK1, Parkin and VDAC1. Inhibition of mitophagy reduced PINK1 expression, enhanced NLRP3 expression, but failed to alter VDAC1. VDAC1 overexpression promoted PINK1 expression, inhibited NLRP3 activation and changed the cell biological behaviors under HG conditions. These findings demonstrate that VDAC1-mediated mitophagy plays a crucial role in regulating NLRP3 inflammasome activation in retinal capillary endothelial cells under HG conditions, suggesting that VDAC1 may be a potential target for preventing or treating DR.

Arginine Regulates NLRP3 Inflammasome Activation Through SIRT1 in Vascular Endothelial Cells.

L-arginine (Arg), a semi-essential amino acid, has recently been shown to attenuate inflammatory response during cardiovascular disease. NLRP3 inflammasome serves a central role in amplification of cellular inflammation. In this study, we aimed to confirm the modulatory effect of Arg on NLRP3 inflammasome and the underlying mechanisms in vascular endothelial cells (ECs). Arg suppressed NLRP3 inflammasome activation in ECs stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP). Moreover, treatment with Arg increased the expression of the deacetylase sirtuin 1 (SIRT1) in ECs. Importantly, knockdown of SIRT1 abolished the inhibitory potential of Arg on the activation of NLRP3 inflammasome. Further study indicated that Arg also alleviated LPS plus ATP-induced the generation of reactive oxygen species (ROS) in ECs. In addition, Arg may regulate NLRP3 inflammasome activation partly through suppression of ROS production. In combination, we speculate that Arg exerts an inhibitory effect on the activation of NLRP3 inflammasome in ECs, which may be partly mediated by SIRT1 and ROS.

Chronic stress promotes acute myeloid leukemia progression through HMGB1/NLRP3/IL-1ß signaling pathway.

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy with poor prognosis and overall survival. Clinical investigations show that chronic stress is commonly present in the course of AML and associated with adverse outcome. However, the underlying molecular mechanisms are elusive. In the present study, a chronic restraint stress mouse model was established to evaluate the effect of stress on AML. We found that mice under chronic stress exhibited significantly increased liver and spleen infiltration of leukemic cells and poorer overall survival. This was accompanied by elevated cellular NLR family pyrin domain containing 3 (NLRP3) and interleukin-1ß (IL-1ß) in the liver or bone marrow, and secreted IL-1ß in the plasma, indicating the activation of inflammasomes under chronic restraint stress. High mobility group box 1 (HMGB1) expression was markedly increased in newly diagnosed AML patients, but reduced in complete remission AML patients. The expression level of HMGB1 was positively correlated with NLRP3 mRNA in AML patients. Knockdown of HMGB1 significantly decreased NLRP3 and IL-1ß expression in AML cell lines, and secreted IL-1ß in supernatant of AML cell culture, while HMGB1 stimulation caused contrary effects. These results implied that HMGB1 could be involved in the regulation of inflammasome activation in AML development. Mice model showed that chronic restraint stress-facilitated proliferation and infiltration of AML cells were largely abrogated by knocking down HMGB1. Knockdown of HMGB1 also ameliorated overall survival and remarkably neutralized NLRP3 and IL-1ß expression under chronic restraint stress. These findings provide evidences that chronic stress promotes AML progression via HMGB1/NLRP3/IL-1ß dependent mechanism, suggesting that HMGB1 is a potential therapeutic target for AML. KEY MESSAGES: • Chronic restraint stress promoted acute myeloid leukemia (AML) progression and mediated NLRP3 inflammasome activation in xenograft mice. • HMGB1 mediated NLRP3 inflammasome activation in AML cells. • Knockdown of HMGB1 inhibited AML progression under chronic stress in vivo.

LncRNA HOTAIR Promotes Neuronal Damage Through Facilitating NLRP3 Mediated-Pyroptosis Activation in Parkinson's Disease via Regulation of miR-326/ELAVL1 Axis.

Parkinson's disease (PD) seriously threatens human's health. Researches have shown a close correlation between long non-coding RNAs (lncRNAs) and PD. However, the biological function of lncRNA homeobox transcript antisense RNA (HOTAIR) in PD remains largely unknown. In this study, we established PD models in vivo and in vitro by using 1-methyl-4-phenyl-2, 3, 6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridinium (MPP+) to assess the role of HOTAIR in pyroptotic cell death and neuronal damage. RNA immunoprecipitation (RIP) and dual luciferase reporter assay were used to verify the interaction between miR-326 and HOTAIR or ELAV like RNA binding protein 1 (ELAVL1). LncRNA HOTAIR was upregulated in PD mice and MPP+ induced SH-SY5Y cells. Additionally, knockdown of HOTAIR notably attenuated the symptom of PD in vivo. Downregulation of HOTAIR could obviously promoted cell viability and suppressed NLR family pyrin domain containing 3 (NLRP3) mediated pyroptotic cell death of SH-SY5Y cells in the presence of MPP+. Further, lncRNA HOTAIR positively regulated ELAVL1 expression by targeting miR-326, and downregulation of HOTAIR or ELAVL1 notably suppressed promotive effects of miR-326 inhibitor on MPP+ induced pyroptosis via activation of NLRP3 inflammasome. Collectively, HOTAIR silencing significantly inhibits neuronal damage through repressing NLRP3 mediated pyroptosis activation via regulation of miR-326/ELAVL1 axis in PD, which may contribute to a better understanding of PD pathogenesis and provide new treatment strategies for this disease.

Slc6a3-dependent expression of a CAPS-associated Nlrp3 allele results in progressive behavioral abnormalities and neuroinflammation in aging mice.

BACKGROUND: An association between neuroinflammation and age-related neurologic disorders has been established but the molecular mechanisms and cell types involved have not been thoroughly characterized. Activity of the proinflammatory NLRP3 inflammasome is implicated in Alzheimer's and Parkinson's disease and our recent studies in patients suggest that dopaminergic neurons within the degenerating mesencephalon express NLRP3 throughout the progression of PD. Here, we directly test the impact of enhanced inflammasome activity in mesencephalic neurons by characterizing motor function, tissue integrity, and neuroinflammation in aging mice harboring hyperactivating mutations within the endogenous murine Nlrp3 locus, enabled only in cells expressing the dopaminergic neuron-specific Slc6a3 promoter. METHODS: We compared mice harboring inducible alleles encoding the cryopyrin-associated periodic syndrome activating mutations Nlrp3A350V and Nlrp3L351P inserted into the endogenous mouse Nlrp3 locus. Tissue specific expression was driven by breeding these animals with mice expressing Cre recombinase under the control of the dopaminergic neuron-specific Slc6a3 promoter. The experimental mice, designed to express hyperactive NLRP3 only when the endogenous mouse Nlrp3 promotor is active in dopaminergic neurons, were analyzed throughout 18 months of aging using longitudinal motor function assessments. Biochemical and histologic analyses of mesencephalic tissues were conducted in 1- and 18-month-old animals. RESULTS: We observed progressive and significant deficits in motor function in animals expressing Nlrp3L351P, compared with animals expressing Nlrp3WT and Nlrp3A350V. Age-dependent neuroinflammatory changes in the mesencephalon were noted in all animals. Analysis of GFAP-immunoreactive astrocytes in the substantia nigra revealed a significant increase in astrocyte number in animals expressing Nlrp3L351P compared with Nlrp3WT and Nlrp3A350V. Further analysis of Nlrp3L351P striatal tissues indicated genotype specific gliosis, elevated Il1b expression, and both morphologic and gene expression indicators of proinflammatory A1 astrocytes. CONCLUSIONS: Dopaminergic neurons have the potential to accumulate NLRP3 inflammasome activators with age, including reactive oxygen species, dopamine metabolites, and misfolded proteins. Results indicate the Nlrp3 locus is active in dopaminergic neurons in aging mice, and that the hyperactive Nlrp3L351P allele can drive neuroinflammatory changes in association with progressive behavioral deficits. Findings suggest neuronal NLRP3 inflammasome activity may contribute to neuroinflammation observed during normal aging and the progression of neurologic disorders.

Curcumin exerts protective effect on PC12 cells against lidocaine-induced cytotoxicity by suppressing the formation of NLRP3 inflammasome.

OBJECTIVE: To explore the protective effect of curcumin on lidocaine-insulted PC12 cells. MATERIALS AND METHODS: We first treated PC12 cells with different doses of lidocaine, and then treated the cells with curcumin or Nod-like receptor pyrin domain3 (NLRP3) inhibitor (MCC950). Subsequently, the cell viability, apoptosis, reactive oxygen species (ROS) production and NLRP3 inflammasome were detected by cell counting kit-8 (CCK8), Annexin V/PI staining, FCM and Western blot analysis, respectively, and the level of IL-1ß in PC12 cells was determined by an enzyme-linked immunosorbent assay (ELISA) kit. RESULTS: Lidocaine inhibited the viability of PC12 cells, and it induced cell apoptosis, promoted ROS release and activated NLRP3 inflammasome in PC12 cells, but its effects were reversed by the treatment of curcumin. Moreover, NLRP3 over-expression also induced cytotoxicity in PC12 cells, which was also rescued by the treatment of curcumin. CONCLUSIONS: Our study indicates that curcumin exerts protective effect against lidocaine-induced cytotoxicity on PC12 cells by suppressing the activity of NLRP3 inflammasome, which provides new ideas on screening natural product for neurological damage therapy.

Subventricular zone-derived extracellular vesicles promote functional recovery in rat model of spinal cord injury by inhibition of NLRP3 inflammasome complex formation.

Spinal cord injury (SCI) is the destruction of spinal cord motor and sensory resulted from an attack on the spinal cord, which can cause significant physiological damage. The inflammasome is a multiprotein oligomer resulting in inflammation; the NLRP3 inflammasome composed of NLRP3, apoptosis-associated speck-like protein (ASC), procaspase-1, and cleavage of procaspase-1 into caspase-1 initiates the inflammatory response. Subventricular Zone (SVZ) is the origin of neural stem/progenitor cells (NS/PCs) in the adult brain. Extracellular vesicles (EVs) are tiny lipid membrane bilayer vesicles secreted by different types of cells playing an important role in cell-cell communications. The aim of this study was to investigate the effect of intrathecal transplantation of EVs on the NLRP3 inflammasome formation in SCI rats. Male wistar rats were divided into three groups as following: laminectotomy group, SCI group, and EVs group. EVs was isolated from SVZ, and characterized by western blot and DLS, and then injected into the SCI rats. Real-time PCR and western blot were carried out for gene expression and protein level of NLRP3, ASC, and Caspase-1. H&E and cresyl violet staining were performed for histological analyses, as well as BBB test for motor function. The results indicated high level in mRNA and protein level in SCI group in comparison with laminectomy (p < 0.001), and injection of EVs showed a significant reduction in the mRNA and protein levels in EVs group compared to SCI (p < 0.001). H&E and cresyl violet staining showed recovery in neural cells of spinal cord tissue in EVs group in comparison with SCI group. BBB test showed the promotion of motor function in EVs group compared to SCI in 14 days (p < 0.05). We concluded that the injection of EVs could recover the motor function in rats with SCI and rescue the neural cells of spinal cord tissue by suppressing the formation of the NLRP3 inflammasome complex.

Dexmedetomidine exerts dual effects on human annulus fibrosus chondrocytes depending on the oxidative stress status.

Dexmedetomidine (Dex) is an anesthetic widely used in lumbar discectomy, but its effect on chondrocytes remains unclear. Dex is speculated to promote cartilage degeneration by activating α-2 adrenergic receptor. However, the antioxidative and anti-inflammatory effects of Dex implied the potential chondrocyte protective effect under stress conditions. The present study aimed to determine the effect of Dex on chondrocytes under non-stress and stress conditions. Chondrocytes were isolated from human annulus fibrosus (AF) tissues and oxidative stress was induced by treatment with 1 mM hydrogen peroxide (H2O2). Chondrocytes were treated with Dex alone or in combination with H2O2 Treatment with Dex alone decreased mRNA expression of COL2A1 and increased that of MMP-3 and MMP-13, thus contributing to cartilage degeneration. However, Dex prevented H2O2-induced death and degeneration of chondrocytes partly by enhancing antioxidant capacity. Mechanistically, Dex attenuated H2O2-mediated activation of NF-κB and NACHT, LRR, and PYD domains-containing protein 3 (NLRP3), both of which play key roles in inflammation and inflammatory damage. Dex inactivated NLRP3 through the suppression of NF-κB and JNK signals. Co-treatment with Dex and H2O2 increased protein level of XIAP (X-linked inhibitor-of-apoptosis, an anti-apoptosis protein), compared with H2O2 treatment alone. H2O2 treatment increased the expression of neural precursor cell expressed developmentally down-regulated protein 4 (NEDD4) that is a ubiquitin ligase targeting XIAP. However, Dex decreased the amount of NEDD4 adhering to XIAP, thus protecting XIAP protein from NEDD4-mediated ubiquitination and degradation. Given that surgery inevitably causes oxidative stress and inflammation, the protective effect of Dex on chondrocytes during oxidative stress is noteworthy and warrants further study.

Evodiamine prevents dextran sulfate sodium-induced murine experimental colitis via the regulation of NF-κB and NLRP3 inflammasome.

Evodiamine (EVO), an extraction from the traditional Chinese medicine Evodia rutaecarpa, has been reported to possess anti-inflammatory, anti-tumor and other pharmacological activities. However, the effectiveness of EVO to relieve dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) has not been evaluated. In this study, the protective effects and mechanisms of EVO on DSS-induced UC mice were investigated. The results indicated that treatment with EVO ameliorated DSS-induced UC mice body weight loss, disease activity index (DAI), colon length shortening, colonic pathological damage, and myeloperoxidase (MPO) activity. The production of TNF-α, IL-1ß and IL-6 was also significantly inhibited by EVO. Further mechanistic results showed that EVO restrained the inflammation by regulating NF-κB signal and NLRP3 inflammasome. Furthermore, results also showed that EVO contributed to the tight junction (TJ) architecture integrity by modulating the expression of zonula occludens-1 (ZO-1) and occludin during colitis. Surprisingly, treatment with EVO reduced the concentration of plasmatic lipopolysaccharide (LPS) and re-balanced the levels of Escherichia coli and Lactobacillus. These findings suggested that EVO may have a potential protective effect on DSS-induced colitis and may be useful for the prevention and treatment of UC.

MiR-223-3p overexpression inhibits cell proliferation and migration by regulating inflammation-associated cytokines in glioblastomas.

Glioblastoma(GBM) is most common brain tumor in adults. Currently standard treatments have limited effect to increase the survival, because there are still largely unclear mechanisms in glioblastoma development. miR-223 was involved in various types of cancer, however, the function of miR-223-3p in GBM was still unclear. In our study, real-time PCR was performed to exam the expression level of miR-223-3p and NLRP3 (Nucleotide-binding oligomerization domain(NOD)-like receptor family PYRIN domain containing-3) in GBM tissues. Following that, mimic or inhibitor of miR-223-3p were used to modulate miR-223-3p expression in GBM cell lines respectively. Then, we analyzed cell proliferation and migration by cell counting kit and transwell assay. Further, western blot was performed to detect several inflammation-associated cytokines level in GBM cell lines. We found that miR-223-3p was decreased but NLRP3 was increased in GBM tissues. Treatment with miR-223-3p mimic inhibits cell proliferation and migration via decreasing several inflammation-associated cytokines, including interleukin-1ß (IL-1ß), monocyte chemoattractant protein-1 (MCP-1), IL-8 and IL-18. Importantly, these effects induced by miR-223-3p could be attenuated by NLRP3 overexpression, which was considered as one of target genes of miR-223-3p. In conclusion, these results indicated that miR-223-3p might act as a suppressor and a potential therapy target of GBM.

The involvement and mechanism of febuxostat in non-alcoholic fatty liver disease cells.

It has been proved that hyperuricemia is associated with non-alcoholic fatty liver disease (NAFLD). The xanthine oxidase (XO) inhibitor, febuxostat, decreases free fatty acids-induced fat accumulation in HFDT-fed mice. Here, it is shown that febuxostat attenuates fat accumulation and reactive oxygen species (ROS) in HepG2 cells. It was further found that the underlying mechanism is related to the reduction in expression of NLRP3/caspase-1/IL-18/IL-1beta and improved insulin resistance (IR). This finding highlights the possible molecular pathways involving NLRP3 activation for management of ROS and insulin IR. In conclusion, febuxostat may be a promising potential treatment for patients with NAFLD.

Mice with miR-146a deficiency develop severe gouty arthritis via dysregulation of TRAF 6, IRAK 1 and NALP3 inflammasome.

BACKGROUND: MicroRNAs (miRNAs) serve as important regulators of inflammatory and immune responses and are implicated in several immune disorders including gouty arthritis. The expression of miR-146a is upregulated in the peripheral blood mononuclear cells of patients with inter-critical gout when compared to normouricemic and hyperuricemic controls and those patients with acute gout flares. However, the role of miR-146a in the development of gout remains unknown. Here, we used miR-146a knockout (KO) mice to test miR-146a function in a monosodium urate (MSU)-induced gouty arthritis model. METHODS: The footpad or ankle joint of miR-146a KO and wild-type (WT) mice were injected with an MSU suspension to induce acute gouty arthritis. Bone marrow-derived macrophages (BMDMs) were stimulated with MSU and the gene expression of miR-146a; interleukin 1 beta (IL-1ß); tumor necrosis factor-α (TNF-α); and the NACHT, LRR and PYD domains-containing protein 3 (NALP3) inflammasome was evaluated. TNF-α and IL-1ß protein levels in BMDMs were assessed by fluorescence-activated cell sorting and western blot analyses. Gene and protein levels of TNF receptor-associated factor 6 (TRAF6) and IL-1 receptor-associated kinase (IRAK1), the targets of miR-146a, were also measured. RESULTS: Significantly increased paw swelling and index and ankle joint swelling were observed in miR-146a KO mice compared to WT controls after MSU treatment. MiR-146a expression in BMDMs from WT mice was dramatically upregulated at 4 h following MSU stimulation. Additionally, the expression of IL-1ß, TNF-α, and NALP3 was higher in BMDMs from miR-146a KO mice after exposure to MSU crystals compared to those from WT mice. Consistent with the observed gene expression, the IL-1ß and TNF-α proteins were upregulated in miR-146a KO mice. Additionally quantitative RT-PCR and western blot demonstrated that TRAF6 and IRAK1 were dramatically upregulated in BMDMs from miR-146 KO mice compared to those from WT mice. CONCLUSIONS: Collectively, these observations suggest that miR-146a provides negative feedback regulation of gouty arthritis development and lack of miR-146a enhances gouty arthritis via upregulation of TRAK6, IRAK-1, and the NALP3 inflammasome function.

Species-specific differences in regulation of macrophage inflammation by the C3a-C3a receptor axis.

Complement is an important arm of the innate immune system. Recent studies have shown that products of complement pathway activation can interact directly with other innate immune signaling molecules, including TLRs and inflammasome family members, during some infectious and chronic inflammatory disorders. Activation of the complement system generates anaphylatoxins, such as C3a and C5a, which modulate inflammation. However, the biological effects of interactions between the anaphylatoxins with their receptors may vary across species. In this study, we demonstrate that human complement and rat complement differ in the way they modulate the inflammatory response to the human pathogen, Neisseria gonorrhoeae, as well as purified pathogen-associated ligands, such as LPS. While rat serum down-regulates MyD88-dependent pro-inflammatory cytokine responses in macrophages, human serum has no effect, or in some cases an enhancing effect. Further, the inhibitory effect of rat serum on otherwise pro-inflammatory stimuli is mediated by complement, specifically C3a-C3a receptor interactions, via an undefined signaling mechanism that down-regulates the transcription factor, NF-κB and NLRP3 inflammasome-mediated caspase-1 activation. This study highlights important functional differences between rodent and human complement that could explain some of the differences in immune responses between these two species. Understanding the crosstalk between complement and other arms of the innate immune system will facilitate the development of better anti-inflammatory therapeutics.

BMSCs-derived miR-223-containing exosomes contribute to liver protection in experimental autoimmune hepatitis.

Autoimmune hepatitis is a chronic inflammatory disease in the liver with potential to the development of liver fibrosis. Recent evidences suggest that bone marrow derived mesenchymal stem cells (BMSCs) may exert its therapeutic activity through exosomes. Moreover, miR-223 is highly expressed in BMSCs and plays an important role in autoimmune diseases. Therefore, in this study, hepatoprotective role of BMSCs and miR-223 was investigated in both mice and hepatocytes. Liver antigen S100 was used to establish autoimmune hepatitis model in mice while LPS and ATP were used to establish cell injury model in hepatocyte. Before the experiments, BMSCs were infected with pre-miR-223 and transfected with miR-223 inhibitor respectively. Exosomes from bone marrow stem cells were isolated by ultracentrifugation. Liver injury was evaluated by serum levels of ALT and AST as well as liver histology. Inflammation and cell death were examined by inflammatory cytokines and lactase dehydrogenase respectively. Both BMSCs-exo and BMSCs-exomiR-223(+) significantly reversed either S100 or LPS/ATP induced injury in mice and hepatocytes. Meanwhile, the expressions of cytokines, NLRP3 and caspase-1 were also downregulated by BMSCs-exo and BMSCs-exomiR-223(+) at both protein and mRNA levels in mice and hepatocytes. Moreover, BMSCs-exomiR-223(-) reverses the effects of BMSCs-exo and BMSCs-exomiR-223(+) in mouse AIH and in hepatocytes. In conclusion, bone marrow stem cell derived exosomes can protect liver injury in an experimental model of autoimmune hepatitis and the mechanism could be related to exosomal miR-223 regulation of NLRP3 and caspase-1.

Effects of chronically increased VEGF-A on the aging heart.

Whether approaches to chronically increase VEGF-A in the heart may have beneficial effects and prevent the development of heart failure, in part by improving cardiac perfusion, or whether this increase could have detrimental effects on cardiac performance in the aging heart, has not been tested yet. In this study, a genetic mouse model with a chronic increase in VEGF-A in the heart is shown to have increased cardiac angiogenesis and develop cardiac hypertrophy with enhanced basal cardiac performance with age progression. However, in aged hearts, this increase in VEGF-A was associated with higher expression of fetal cardiac genes and reduced cardiac performance after ß-agonistic stress, features consistent with pathologic cardiac hypertrophy. Expression of Nod-like receptor protein (NLRP)-3 was increased in the hearts of the mice, and its genetic inactivation prevented increased fetal cardiac gene expression and partially rescued the impaired cardiac performance after ß-agonistic stimulation in aged hearts without reducing cardiac angiogenesis or hypertrophy. Thus, although a chronic increase in cardiac VEGF-A may improve cardiac perfusion, long-term upregulation of VEGF-A leads to reduced cardiac performance under stress, an effect that can be partially inhibited by NLRP3 inactivation. Targeting NLRP3 shifts the VEGF-A-induced cardiac hypertrophy from a pathologic toward a more physiologic hypertrophy.-Marneros, A. G. Effects of chronically increased VEGF-A on the aging heart.

Helicobacter pylori controls NLRP3 expression by regulating hsa-miR-223-3p and IL-10 in cultured and primary human immune cells.

Inflammasome-mediated production of mature IL-1ß and IL-18 cytokines represents an important innate immune response against infecting pathogens. Helicobacter pylori, one of the most successful and persistent human pathogens, induces severe inflammation leading to gastritis and more serious gastric diseases. H. pylori modulates different immune responses for its survival and inflammasome signaling is manipulated by the cag pathogenicity island ( cagPAI), urease and VacA cytotoxin. Here we report that H. pylori regulates NLRP3 expression, an inflammasome forming regulator, in infected THP-1 monocytes. This response was independent of the major H. pylori pathogenicity-associated factors CagA, VacA, Cgt, FlaA and cagPAI. Two NLRP3 expression controlling factors, the NLRP3 mRNA targeting microRNA hsa-miR-223-3p and cytokine IL-10, were found to work in tandem for its regulation. H. pylori infection also induced copious amount of pro-IL-1ß in THP-1 monocytes/macrophages but secreted a very low amount of mature IL-1ß. Moreover, secreted IL-10 correlated with the down-regulation of nigericin-induced NLRP3 inflammasome activation of LPS-primed THP-1 monocytes and human PBMCs from volunteers. However, H. pylori-treated PBMCs secreted significantly more mature IL-1ß throughout the infection period, which suggests a different mode of activation. Taken together, this study demonstrates targeting of inflammasome-forming NLRP3, an important innate immunity component, and crucial manipulation of pro- and anti-inflammatory cytokines in H. pylori infection.