Pyrin Domain Protein Research Articles

Danshenxinkun B protects human umbilical vein endothelial cells against ox-LDL-induced injury by inhibiting pyroptosis and the NF-κB/NLRP3 pathway

To investigate the protective effect of Danshenxinkun B against oxidized low-density lipoprotein (ox-LDL)- induced human umbilical vein endothelial cell (HUVEC) injury and explore the underlying mechanism. HUVECs cultured in the presence of 10% fetal bovine serum were treated with ox-LDL (100 μg/mL), ox-LDL+0.1% dimethyl sulfoxide (DMSO), or ox-LDL+Danshenxinkun B (100 ng/mL, dissolved in DMSO) for 24 h. The changes in lactate dehydrogenase (LDH) release was detected, and qRT-PCR was used to detect the mRNA expressions of nuclear factor-κB1 (NF-κB1), nucleotide binding oligomerization domain-like receptor family pyrin domain protein 3 (NLRP3), gasdermin D (GSDMD) and interleukin- 1β (IL-1β). The protein expressions of NF-κB1, NLRP3, caspase-1, IL-1β and GSDMD-N were detected with Western blotting. Immunofluorescence assay was performed to examine the changes in GSDMD expression in the cells. Compared with the normal control cells, the cells treated with ox-LDL alone or in combination with DMSO exhibited significantly increased LDH release, mRNA expressions of NF-κB1, NLRP3, GSDMD, and IL- 1β and the protein levels of NF-κB1, NLRP3, IL- 1β, GSDMD-N and caspase-1 (P<0.01), which were all significantly lowered by treatment with Danshenxinkun B (P<0.05 or 0.01). Danshenxinkun B treatment significantly inhibited GSDMD expression on the cell membrane and restricted its entry into the cell nucleus. Danshenxinkun B alleviates ox-LDL-induced HUVEC injury possibly by suppressing pyroptosis mediated by NLRP3 inflammatory bodies and inhibiting the NF-κB/NLRP3 signaling pathway.

Restraint stress promotes monobenzone-induced depigmentation in mice via the activation of glucocorticoid receptor/macrophage migration inhibitory factor signaling pathway

Psychological stress triggers onset and development of vitiligo in humans. However, the mechanism of psychological stress on vitiligo remains unclear. The study aims to investigate whether psychological stress promotes vitiligo and explore the underlying mechanism. A depigmentation mouse model induced by applying a skin-bleaching reagent monobenzone to dorsal skin and an in vitro HaCaT keratinocyte death model induced by monobenzone were employed to explore the effect of restraint stress, which mimics psychological stress, on depigmentation. The results indicated that restraint stress promoted vitiligo-related depigmentation, vacuolisation, spongiosis, CD8+ T lymphocyte infiltration, and loss of melanocytes in the skin. Restraint stress activated cutaneous NLR family containing pyrin domain protein 3 (NLRP3) inflammasome. In addition, restraint stress aggravated anxiety-like behaviors and increased levels of macrophage migration inhibitory factor (MIF) and corticosterone in the circulation, accompanied with decreasing the expression of cutaneous 8-oxoguanine DNA glycosylase (OGG1) in depigmentation mice. In vitro experiments demonstrated that activation of glucocorticoid receptor (GR) by cortisol upregulated NLRP3 expression dependent on MIF, and directly decreased the transcription of OGG1. Blockade of MIF reversed the NLRP3 signal in restraint stress-induced depigmentation mice. In conclusion, restraint stress promotes vitiligo-related depigmentation in mice via the activation of GR/MIF signaling pathway. The findings provide a theoretical basis for prevention and treatments of vitiligo with therapies of targeting GR, MIF, and OGG1.

The role of NLRP3 inflammasome-mediated pyroptosis in ischemic stroke and the intervention of traditional Chinese medicine.

Ischemic stroke (IS) is the second leading cause of death and disability in the world. Pyroptosis, a form of programmed cell death initiated by caspases, participates in the occurrence and development of IS. Because it can increase cell membrane permeability, mediate the release of inflammatory factors, and aggravate inflammation, inhibiting this process can significantly reduce the pathological injury of IS. The nucleotide binding oligomerization domain-like receptor family pyrin domain protein 3 (NLRP3) is a multiprotein complex whose activation is the core link of pyroptosis. In recent years, studies have reported that traditional Chinese medicine (TCM) could regulate pyroptosis mediated by NLRP3 inflammasome through multi-channel and multi-target networks and thus exert the effect against IS. This article reviews 107 papers published in recent years in PubMed, Chinese National Knowledge Infrastructure (CNKI), and WanFang Data in recent years. It has found that the activation factors of NLRP3 inflammasome include ROS, mitochondrial dysfunction, K+, Ca2+, lysosome rupture, and trans-Golgi breakdown. TLR4/NF-κB/NLRP3, ROS/TXNIP/NLRP3, AMPK/Nrf2/NLRP3, DRP1/NLRP3, TAK1/JNK/NLRP3 signaling pathways regulate the initiation and assembly of the NLRP3 inflammasome, subsequently induce pyroptosis, affecting the occurrence and development of IS. TCM can affect the above signaling pathways and regulate the pyroptosis mediated by NLRP3 inflammasome, so as to play a protective role against IS, which provides a new entry point for discussing the pathological mechanism of IS and a theoretical basis for developing TCM treasure house.

Experimental study of cardioprotective effects of Cinnamomi Ramulus and Cinnamomi Cortex formula granules on myocardial ischemia/reperfusion injury in rats based on efficacy of "warming and coordinating heart Yang"

This study aimed to parallelly investigate the cardioprotective activity of Cinnamomi Ramulus formula granules(CRFG) and Cinnamomi Cortex formula granules(CCFG) against acute myocardial ischemia/reperfusion injury(MI/RI) and the underlying mechanism based on the efficacy of &quot;warming and coordinating the heart Yang&quot;. Ninety male SD rats were randomly divided into a sham group, a model group, CRFG low and high-dose(0.5 and 1.0 g·kg~(-1)) groups, and CCFG low and high-dose(0.5 and 1.0 g·kg~(-1)) groups, with 15 rats in each group. The sham group and the model group were given equal volumes of normal saline by gavage. Before modeling, the drug was given by gavage once a day for 7 consecutive days. One hour after the last administration, the MI/RI rat model was established by ligating the left anterior descending artery(LAD) for 30 min ischemia followed by 2 h reperfusion except the sham group. The sham group underwent the same procedures without LAD ligation. Heart function, cardiac infarct size, cardiac patho-logy, cardiomyocyte apoptosis, cardiac injury enzymes, and inflammatory cytokines were determined to assess the protective effects of CRFG and CCFG against MI/RI. The gene expression levels of nucleotide-binding oligomerization domain-like receptor family pyrin domain protein 3(NLRP3) inflammasome, apoptosis-associated speck-like protein containing a CARD(ASC), cysteinyl aspartate specific proteinase-1(caspase-1), Gasdermin-D(GSDMD), interleukin-1β(IL-1β), and interleukin-18(IL-18) were determined by real-time quantitative polymerase chain reaction(RT-PCR). The protein expression levels of NLRP3, caspase-1, GSDMD, and N-GSDMD were determined by Western blot. The results showed that both CRFG and CCFG pretreatments significantly improved cardiac function, decreased the cardiac infarct size, inhibited cardiomyocyte apoptosis, and reduced the content of lactic dehydrogenase(LDH), creatine kinase MB isoenzyme(CK-MB), aspartate transaminase(AST), and cardiac troponin Ⅰ(cTnⅠ). In addition, CRFG and CCFG pretreatments significantly decreased the levels of IL-1β, IL-6, and tumor necrosis factor-α(TNF-α) in serum. RT-PCR results showed that CRFG and CCFG pretreatment down-regulated the mRNA expression levels of NLRP3, caspase-1, ASC, and downstream pyroptosis-related effector substances including GSDMD, IL-18, and IL-1β in cardiac tissues. Western blot revealed that CRFG and CCFG pretreatments significantly decreased the protein expression levels of NLRP3, caspase-1, GSDMD, and N-GSDMD in cardiac tissues. In conclusion, CRFG and CCFG pretreatments have obvious cardioprotective effects on MI/RI in rats, and the under-lying mechanism may be related to the inhibition of NLRP3/caspase-1/GSDMD signaling pathway to reduce the cardiac inflammatory response.

Lutein isolated from Scenedesmus obliquus microalga boosts immunity against cyclophosphamide-induced brain injury in rats

Lutein is a naturally potent antioxidant carotenoid synthesized in green microalgae with a potent ability to prevent different human chronic conditions. To date, there are no reports of the immune-stimulating effect of pure lutein isolated from Scenedesmus obliquus. Thus, we isolated the natural lutein from S. obliquus and evaluated its effectiveness as an immunostimulant against cyclophosphamide-induced brain injury. We purified all-E-(3R, 3′R, 6′R)-Lutein from S. obliquus using prep-HPLC and characterized it by 1H- and 13C-NMR spectroscopy. We assigned rats randomly to four experimental groups: the Control group got a vehicle for lutein dimethyl sulfoxide for ten successive days. The Cyclophosphamide group received a single i.p injection of Cyclophosphamide (200 mg/kg). Lutein groups received 50 and 100 (mg/kg) of lutein one time per day for ten successive days after the cyclophosphamide dose. Lutein administration reduced brain contents of Macrophage inflammatory protein2 (MIP2), cytokine-induced- neutrophil chemoattractant (CINC), and Matrix metalloproteinase 1 (MMP1). Besides, it lowered the contents of interleukin 1 beta (IL-1β) and interleukin 18 (IL-18), associated with low content of NLR pyrin domain protein 3 (NLRP3) and consequently caspase-1 compared to the cyclophosphamide group. In the histomorphometric analysis, lutein groups (50 and 100 mg/Kg) showed mild histopathological alterations as they significantly reduced nuclear pyknosis numbers by 65% and 69% respectively, compared to the cyclophosphamide group. This is the first study that showed the immunomodulatory roles of lutein against cyclophosphamide-induced brain injury via decreasing neuroinflammation, chemokines recruitment, and neuron degeneration with the modulation of immune markers. Hence, lutein can be an effective immunomodulator against inflammation-related immune disorders.

Piperazine ferulate attenuates gentamicin-induced acute kidney injury via the NF-κB/NLRP3 pathway

BackgroundPiperazine ferulate (PF) is widely used in chronic nephritis and nephrotic syndrome in clinic. PF can improve diseases related inflammation by inhibiting the activation of nuclear factor kappa-B (NF-κB) signal. Acute kidney injury (AKI) is usually associated with the occurrence and development of renal inflammation. However, the nephroprotective effect and anti-inflammatory mechanisms of PF on AKI are not clear. PurposeThis study aimed to investigate the nephroprotective effects of PF on gentamicin (GM) induced AKI in rats and its potential mechanisms. MethodsMale Sprague Dawley (SD) rats were intraperitoneally injected with GM (100 mg/kg/day) with or without PF (50 and 100 mg/kg/day) for 7 consecutive days. In vitro, the NRK-52e cells were exposed to GM (7 mg/ml) with or without PF (62.5 μg/ml) treatment. The renal injury and cell damage were assessed subsequently. ResultsOur findings showed that PF treatment can significantly improve renal function, reduce renal pathological changes, and attenuate inflammatory response in rats treated with gentamicin. Besides, PF could significantly reduce the cell damage and cellular inflammatory response. In terms of mechanisms, our study revealed that PF can evidently inhibit the activation of NF-κB and nod-like receptor family pyrin domain protein 3 (NLRP3) inflammasome. Meanwhile, it could down regulate the expressions of protein and gene of p-IKKα, p-IKKβ, p-p65, p65, p50, p105, NLRP3 and IL-1β. ConclusionOur findings showed that PF may improve inflammation by inhibiting the NF-κB/NLRP3 pathway, so as to attenuate AKI.

Quyu Shengxin Decoction Alleviates DSS-Induced Ulcerative Colitis in Mice by Suppressing RIP1/RIP3/NLRP3 Signalling.

Purpose To study the therapeutic effect of Quyu (QY) Shengxin (SX) decoction (QYSXD) in mice with dextran sulfate sodium- (DSS-) induced ulcerative colitis and to investigate the effects of QYSXD on the regulation of the receptor-interacting protein kinase 1 (RIP1)/receptor-interacting protein kinase 3 (RIP3)/nucleotide-binding oligomerization domain-like receptor family pyrin domain protein 3 (NLRP3) signaling pathway. Method Thirty-six mice were randomly divided into the following 6 groups: the experimental group (QYSX group), the model group (DSS group), the positive control group (5-aminosalicylic acid (5-ASA) group), the control group, the first component group (QY group), and the second component group (SX group). Each group included 6 mice. Ulcerative colitis (UC) was induced in the mice by providing 3.5% DSS in drinking water. The mice were weighed every day to evaluate the disease activity index (DAI). After 7 days, the mice were sacrificed, and colonic tissues were obtained for colon length measurement. The morphological changes in the colon and the pathological scores of the mice in each group were observed by hematoxylin-eosin (HE) staining. The messenger ribonucleic acid (mRNA) and protein expression levels of RIP1, RIP3, dynamin-related protein 1 (Drp1), NLRP3, cysteinyl aspartate specific proteinase-1 (caspase-1), interleukin (IL)-1β, and IL-18 in the colon tissues of the mice in each group were detected and compared by real-time quantitative reverse transcription PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). The levels of RIP1, RIP3, NLRP3, IL-1β, and IL-8 in the colonic mucosa were detected by ELISA. Western blotting was used to compare the protein expression of Drp1, caspase-1, mitochondrial fission protein 1 (FIS1), and mitophagy-associated protein light chain 3a/b (LC3a/b) among groups. The levels of reactive oxygen species (ROS) in the colonic mucosal cells were compared by immunofluorescence. Results Compared with those in the DSS group, the mice with DSS-induced colitis in the QYSX group exhibited clearly higher body weights (P < 0.05) and DAI scores (P < 0.05). The colon lengths of the mice in the QYSX group were longer than those in the DSS group (P < 0.05), and the pathological score of the QYSX group was lower than that of the DSS group (P < 0.05). The RIP1, RIP3, Drp1, IL-1β, IL-18, and caspase-1 mRNA levels in the QYSX, 5-ASA, SX, and QY groups were significantly lower than those in the DSS group (P < 0.05), but there were no differences between the QYSX group and the 5-ASA group. The levels of RIP1, RIP3, NLRP3, IL-1β, and IL-18 in the QYSX group were lower than those in the DSS group (P < 0.01). The levels of Drp1, caspase-1, FIS1, and LC3a/b in the QYSX group and the 5-ASA group were lower than those in the DSS group (P < 0.05). The levels of ROS in the colonic mucosal cells in the QYSX, 5-ASA, and QY groups were lower than those in the DSS group (P < 0.05). Conclusion QYSXD has certain therapeutic effects on DSS-induced colitis in mice and may be as effective as 5-ASA. QY and SX decoctions also have certain effects on colitis; however, these decoctions are not as beneficial as QYSXD. QYSXD may ameliorate colitis by inhibiting the expression of RIP1/RIP3/NLRP3 pathway-related proteins and reversing mitochondrial dysfunction to control inflammation.

P2X7 Receptor Antagonist Attenuates Retinal Inflammation and Neovascularization Induced by Oxidized Low-Density Lipoprotein.

Age-related macular degeneration (AMD) is a common and severe blinding disease among people worldwide. Retinal inflammation and neovascularization are two fundamental pathological processes in AMD. Recent studies showed that P2X7 receptor was closely involved in the inflammatory response. Here, we aim to investigate whether A740003, a P2X7 receptor antagonist, could prevent retinal inflammation and neovascularization induced by oxidized low-density lipoprotein (ox-LDL) and explore the underlying mechanisms. ARPE-19 cells and C57BL/6 mice were treated with ox-LDL and A740003 successively for in vitro and in vivo studies. In this research, we found that A740003 suppressed reactive oxygen species (ROS) generation and inhibited the activation of Nod-like receptor pyrin-domain protein 3 (NLRP3) inflammasome and nuclear factor-κB (NF-κB) pathway. A740003 also inhibited the generation of angiogenic factors in ARPE-19 cells and angiogenesis in mice. The inflammatory cytokines and phosphorylation of inhibitor of nuclear factor-κB alpha (IKBα) were repressed by A740003. Besides, ERG assessment showed that retinal functions were remarkably preserved in A740003-treated mice. In summary, our results revealed that the P2X7 receptor antagonist reduced retinal inflammation and neovascularization and protected retinal function. The protective effects were associated with regulation of NLRP3 inflammasome and the NF-κB pathway, as well as inhibition of angiogenic factors.

Recombinant pyrin domain protein attenuates allergic inflammation by suppressing NF-κB pathway in asthmatic mice.

Pyrin domain (PYD), a subclass of protein motif known as the death fold, is frequently involved in inflammation and immune responses. PYD modulates nuclear factor-kappa B (NF-κB) signalling pathway upon various stimuli. Herein, a novel recombinant pyrin domain protein (RPYD) was generated. Its role and mechanism in inflammatory response in an ovalbumin (OVA) induced asthma model was investigated. After OVA challenge, there was inflammatory cell infiltration in the lung, as well as airway hyper-responsiveness (AHR) to inhaled methacholine. In addition, eosinophils increased in the bronchoalveolar lavage fluids, alone with the elevated levels of Th-2 type cytokines [interleukin (IL)-4, IL-5 and IL-13], eotaxin, and adhesion molecules. However, the transnasal administration of RPYD before the OVA challenge significantly inhibited these asthmatic reactions. Moreover, RPYD markedly suppressed NF-κB translocation, reduced phosphorylation of p38 MAPK, and thus attenuated the expression of intercellular adhesion molecule 1 and IL-6 in the BEAS-2B cells stimulated by proinflammatory cytokines invitro. These findings indicate that RPYD can protect asthma host from OVA-induced airway inflammation and AHR via down-regulation of NF-κB and p38 MAPK activities. RPYD may be used as a potential medicine for the treatment of asthma in clinic.

Inflammasomes are important mediators of prostatic inflammation associated with BPH.

BackgroundThere is mounting evidence to support the role of inflammation in benign prostate hyperplasia (BPH), and a recent study reported expression of inflammasome derived cytokine IL-18 in prostate biopsy of BPH patients. Here we examined the expression of inflammasome-derived cytokines and activation of nucleotide-binding oligomerization domain-like receptor with pyrin domain protein 1 (NLRP) 1 inflammasome in a rat model of prostatic inflammation relevant to BPH.MethodsProstatic inflammation was experimentally induced in three-month-old male Sprague–Dawley rats by intraprostatic injection (50 μL) of either 5 % formalin or saline (sham) into the ventral lobes of prostate. 7 days later, prostate and bladder tissue was harvested for analysis of inflammasome by Western blot, immunohistochemistry and downstream cytokine production by Milliplex.ResultsExpression of interleukins, CXC and CC chemokines were elevated 2-15 fold in formalin injected prostate relative to sham. Significant expression of NLRP1 inflammasome components and caspase-1 in prostate were associated with significant elevation of pro and cleaved forms of IL-1β (25.50 ± 1.16 vs 3.05 ± 0.65 pg/mg of protein) and IL-18 (1646.15 ± 182.61 vs 304.67 ± 103.95 pg/mg of protein). Relative to prostate tissue, the cytokine expression in bladder tissue was much lower and did not involve inflammasome activation.ConclusionsSignificant upregulation of NLRP1, caspase-1 and downstream cytokines (IL-18 and IL-1β) suggests that a NLRP1 inflammasome is assembled and activated in prostate tissue of this rat model. Recapitulation of findings from human BPH specimens suggests that the inflammasome may perpetuate the inflammatory state associated with BPH. Further clarification of these pathways may offer innovative therapeutic targets for BPH-related inflammation.

Retinal ischemia/reperfusion injury is mediated by Toll-like receptor 4 activation of NLRP3 inflammasomes.

Retinal ischemia/reperfusion (IR) is common in eye disorders. Pattern-recognition receptors (PRRs) are reported to initiate sterile inflammatory response. The role of PRRs in retinal IR injury is currently unknown. Thus, we investigated the expression and function of membrane and cytoplasmic PRRs during retinal IR. Retinal IR was induced in adult Brown Norway rats by clipping the retinal vessels for 30 minutes. RNA and proteins were extracted during the course of reperfusion, and the expression levels of the following proteins were determined: Toll-like receptor 2 (TLR2), TLR4, myeloid differentiation factor 88 (MyD88), TNF receptor-associated factor 6 (TRAF6), nuclear factor-κB (NF-κB), nucleotide-binding oligomerization domain-like receptor with pyrin domain protein 1 (NLRP1), NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, IL-1β, and IL-18. TLR4 expression in the retina was studied using immunohistochemistry. In addition, a TLR4 inhibitor was injected into the vitreous body as a therapeutic agent. After the treatment of TLR4 inhibitors, the levels of the above factors were evaluated, the apoptosis of cells in the retina, expression of cleaved-caspase-3 (c-casp-3), death of retinal ganglion cells, and the retina electroretinography was assessed. After releasing the artery clamp, the retinal vessels were reperfused in 5 minutes. During the reperfusion, TLR4, MyD88, TRAF6, NF-κB, NLRP1, NLRP3, mature IL-1β, and IL-18 were upregulated, but not TLR2. In the IR model, TLR4 was highly expressed in ganglion cell and glia cell. Additionally, the inhibition of TLR4 significantly downregulated the activation of NLRP3, but not NLRP1, and the secretion of mature IL-1β and IL-18 also were inhibited. Moreover, the TLR4 inhibitor partially attenuated the injury of the retina, including alleviated retina apoptosis, downregulated c-casp-3 expression, rescued retinal ganglion cells death, and restored retina function. These findings suggest that TLR4-signaling activation, triggered by damage-associated molecular patterns, regulates the activation of the NLRP3 inflammasomes and is responsible for the function of the retina in retinal IR injury.

The inhibitory effects and mechanism of Pyrin recombination protein on airway inflamation in mouse with bronchial asthma

Objective To investigate the blocking effects of Pyrin domain protein on mouse allergic airway inflammation induced by ovalbumin and its mechanism.Methods Forty male BALB/c mice were randomly divided into 4 groups with 10 mice in each group.Control group:mice were treated with saline;OVA group:mice were sensitized and challenged with OVA; Pyrin domain protein 3 d group:mice were sensitized and challenged as asthmatic group and treated with 100 μg/kg triptolide before challenged; Pyrin domain protein 7 d group:mice were sensitized and challenged as asthmatic group and treated with 100 μg/kg triptolide before challenged.All mice were killed 24 h after final OVA challenge.The left lung was isolated for pathological examination.Lung sections were stained with hematoxylin and eosin(HE),Masson's trichrome.The thickness of bronchial airway,bronchial smooth muscle thickness,and the collagen deposition area were measured by image analysig system.The concentrations of IL-4,IL-5,TNF-α and IFN-γ in BALF were measured by ELISA,the RT-PCR and Western blot was performed to detect the mRNA expression of connective tissue growth factor (CTGF),TGF-β 1 mRNA and NF -kB from the right lung tissues.Results In OVA group,the number of inflammatory cells and the concentrations of IL-4,IL-5,TNF-a in BALF and Bronchial airway thickness,bronchial smooth muscle thickness,the collagen deposition area,CTGF,TGF-β1 mRNA and NF-kB in lung tissue were significantly higher than those in control group(P＜0.05).IFN-γ were lower than those in control group( P＜0.05 ).While in Pyrin domain protein 3 d group and Pyrin domain protein 7 d group,the number of inflammatory cells,the concentrations of IL-4,IL-5,TNF-α in BALF and bronchial airway thickness,bronchial smooth muscle thickness,the collagen deposition area and NF-kB in lung tissue were significantly lower than those in OVA group,IFN-γwere higher than those in OVA group( P ＜0.05).In Pyrin domain protein 7 d group CTGF and TGF-β1 mRNA in lung tissue were significantly lower than those in OVA group.Conclusion Pyrin domain protein might inhibits airway inflammation and development of airway remodeling in asthmatic mouse,the possible mechanism might in part by associated with reducing the expression of NF-kB and further inhibiting CTGF,TGF-β1. Key words: Bvonchial asthma; Airway remodeling; Mice; Pyrin recombinant protein

A Poxvirus-Encoded Pyrin Domain Protein Interacts with ASC-1 to Inhibit Host Inflammatory and Apoptotic Responses to Infection

Proinflammatory caspases play an essential role in innate immune responses to infection by regulating the cleavage and activation of proinflammatory cytokines. Activation of these enzymes requires the assembly of an intracellular molecular platform, termed the inflammasome, which is comprised of members of the pyrin domain (PYD)-containing superfamily of apoptosis and inflammation-regulatory proteins. We report here the identification and characterization of a poxvirus-encoded PYD-containing protein that interacts with the ASC-1 component of the inflammasome and inhibits caspase-1 activation and the processing of IL-1beta and IL-18 induced by diverse stimuli. Knockout viruses that do not express this protein are unable to productively infect monocytes and lymphocytes due to an abortive phenotype and are markedly attenuated in susceptible hosts due to decreased virus dissemination and enhanced inflammatory responses at sites of infection. Thus, modulation of inflammasome function constitutes an important immunomodulatory strategy employed by poxviruses to circumvent host antiviral responses.

Apoptotic speck protein-like, a highly homologous protein to apoptotic speck protein in the pyrin domain, is silenced by DNA methylation and induces apoptosis in human hepatocellular carcinoma.

We have identified a novel gene encoding a pyrin domain protein of 89 amino acids that is expressed in various tissues including liver, brain, and spleen. The protein is highly homologous to the pyrin domain of apoptosis-associated speck-like protein (ASC). Therefore, we termed it ASC-like (ASCL). We found that ASCL gene was densely and frequently (80%) methylated in hepatocellular carcinoma (HCC) cell lines. In contrast, normal liver samples did not show any significant methylation. This aberrant methylation correlated well with the suppression of RNA expression. Furthermore, a demethylating agent, 5-aza-2'-deoxycytidine, reactivated the ASCL expression in the methylation-silenced cells, indicating that ASCL is silenced by the associated DNA methylation. ASCL methylation was also found in primary HCC (4 of 17 samples), although the frequency was less than that in cell lines. In addition, we found that ASC was also methylated in primary samples (6 of the 17). Interestingly, either ASCL or ASC methylation was observed in 53% (9 of the 17) of primary HCC samples. Significantly, the restoration of ASCL in the methylation-silenced cells demonstrated growth suppression in colony formation assay. This growth suppression effect of ASCL was supported by apoptotic changes observed in ASCL-transfected cells in which annexin-V binding was positive and caspase-3 was activated. Based on the methylation-silencing and the growth suppression activity, we propose that ASCL plays a significant role in the development of HCC.

The expanding spectrum of systemic autoinflammatory disorders and their rheumatic manifestations.

The authors review the genes, and their respective proteins, responsible for eight autoinflammatory conditions. Familial Mediterranean fever is caused by mutations in pyrin, which is the prototype of a new family of proteins belonging to the death-domain superfamily. This new group of proteins, which regulate apoptosis, inflammation, and cytokine processing, share an approximately 90-amino-acid N-terminal sequence called the PYRIN domain. Mutations in another PYRIN domain protein, termed cryopyrin, are responsible for three clinically defined illnesses, Muckle-Wells syndrome, familial cold autoinflammatory syndrome, and NOMID/CINCA. A related protein encoded by the gene is responsible for the Mendelian disorder, Blau syndrome, and also predisposes to Crohn disease. The gene responsible for PAPA syndrome has recently been identified as, and preliminary results from the authors' laboratory also implicate its protein product in these pathways. Lastly, the authors discuss the broadening genetic and clinical spectrum of TRAPS, an autoinflammatory syndrome resulting from mutations in the 55-kDa receptor for tumor necrosis factor.