Acquired semi-squamatization during chemotherapy suggests differentiation as a therapeutic strategy for bladder cancer

1. Download : Download high-res image (118KB)
2. Download : Download full-size image

     

Streptococcus pneumoniae induces pyroptosis through the regulation of autophagy in murine microglia

Streptococcus pneumoniae is responsible for significant mortality and morbidity worldwide and causes invasive pneumococcal diseases including pneumococcal meningitis. Pyroptosis is caspase-1-dependent inflammatory cell death and is known to be induced by various microbial infections. In the present study, we investigated the molecular mechanisms that regulate pyroptosis induced by S. pneumoniae in microglia. Our results revealed that S. pneumoniae induced pyroptosis through caspase-1 activation and IL-1β production. We also found that the activation of caspase-1 and the maturation of IL-1β and IL-18 in the S. pneumoniae-triggered pyroptotic cell death process were mediated by NLRP3 inflammasome. In addition, pneumococcal infection increased the expression of autophagy-related genes and induced autophagosome formation. We also showed that the inhibition of autophagy promoted pneumococcus-induced pyroptosis. Furthermore, ROS was generated by pneumococcal infection and inhibited caspase-1 activation within 4 h of infection. However, in the late phase of infection, IL-1β secretion and caspase-1-dependent cell death were induced by ROS. These results suggest that autophagy induction transiently delay pyroptosis induced by S. pneumoniae in microglia. Our study also revealed that the activation of caspase-1 and the production of IL-1β were induced by pneumolysin and that pneumolysin triggered pyroptosis in microglial cells. Similar to the in vitro results, S. pneumoniae induced caspase-1 activation and caspase-1-dependent cytokine maturation in the mouse meningitis model. Thus, the present data demonstrate that S. pneumoniae induces pyroptosis in murine microglia and that NLRP3 inflammasome is critical for caspase-1 activation during the process. Furthermore, the induction of autophagy could transiently protect microglia from pyroptosis.     

IFN regulatory Factor-1 induced macrophage pyroptosis by modulating m6A modification of circ_0029589 in patients with acute coronary syndrome

BackgroundPyroptosis is identified as a novel form of inflammatory programmed cell death and has been recently found to be closely related to atherosclerosis (AS). We found that IFN regulatory factor-1(IRF-1) effectively promotes macrophage pyroptosis in patients with acute coronary syndrome (ACS). Subsequent studies have demonstrated that circRNAs are implicated in AS. However, the underlying mechanisms of circRNAs in macrophage pyroptosis remain elusive.MethodsWe detected the RNA expression of hsa_circ_0002984, hsa_circ_0010283 and hsa_circ_0029589 in human PBMC-derived macrophages from patients with coronary artery disease (CAD). The lentiviral recombinant vector for hsa_circ_0029589 overexpression (pLC5-GFP-circ_0029589) and small interference RNAs targeting hsa_circ_0029589 and METTL3 were constructed. Then, macrophages were transfected with pLC5-GFP-circ_0029589, si-circ_0029589 or si-METTL3 after IRF-1 was overexpressed and to explore the potential mechanism of hsa_circ_0029589 involved in IRF-1 induced macrophage pyroptosis.ResultsThe relative RNA expression level of hsa_circ_0029589 in macrophages was decreased, whereas the N6-methyladenosine (m6A) level of hsa_circ_0029589 and the expression of m6A methyltransferase METTL3 were validated to be significantly elevated in macrophages in patients with ACS. Furthermore, overexpression of IRF-1 suppressed the expression of hsa_circ_0029589, but induced its m6A level along with the expression of METTL3 in macrophages. Additionally, either overexpression of hsa_circ_0029589 or inhibition of METTL3 significantly increased the expression of hsa_circ_0029589 and attenuated macrophage pyroptosis.ConclusionOur observations suggest a novel mechanism by which IRF-1 facilitates macrophage pyroptosis and inflammation in ACS and AS by inhibiting circ_0029589 through promoting its m6A modification.     

甜橙黄酮体外抑制氧化应激减轻肾小球微血管内皮细胞焦亡的机制研究

目的 糖尿病肾脏疾病(diabetic kidney disease,DKD)的发病率逐年升高,氧化应激诱发的肾小球微血管内皮损伤与其发生发展具有重大关联,但其潜在机制尚不完全清楚,且治疗策略有限。甜橙黄酮是一种广泛用于治疗心血管疾病的多甲氧基化黄酮类化合物,有研究显示其抗氧化的作用较为显著。然而,甜橙黄酮是否抑制肾小球微血管内皮细胞的氧化应激来延缓DKD的进展尚不清楚。因此,本研究旨在从一个全新的角度探讨DKD发生发展的机制,并证实甜橙黄酮的作用和机理,为DKD的治疗提供新思路。方法 采用Px-12孵育人肾小球微血管内皮细胞(human renal glomerular microvascular endothelial cells, HRGEC)在体外建立细胞氧化损伤模型。根据光镜观察细胞形态、细胞活性检测试剂盒-8明确细胞活性、并使用(reactive oxygen species ,SROS)/O_^2?荧光探针测定各组HRGEC细胞氧化应激水平的差异。通过透射电镜观察各组细胞膜形态的变化以及western blot检测膜穿孔蛋白(gasdermin D,GSDMD)蛋白表达的变化来明确细胞焦亡的情况。最后通过增加氧化应激抑制剂和细胞外调节蛋白激酶(extracellular regulated protein kinases, ERK1/2)抑制剂,采用western blot探讨间隙连接、丝裂原活化蛋白激酶(mitogen-activated protein kinases, MAPK)信号通路在HRGEC细胞焦亡中的调控关系以及甜橙黄酮的作用机理。结果 Px-12可诱导HRGEC细胞细胞膜完整性破坏,并可使 GSDMD蛋白剪切暴露其NT端,出现细胞焦亡的发生；Px-12可明显上调ROS/O_^2-的表达,激活氧化应激水平；甜橙黄酮可明显的抑制Px-12诱导的ROS/O_^2-增加,同时能够减少Px-12诱导的GSDMD-NT的形成和ERK的磷酸化；Px-12可诱导间隙连接蛋白43(Connexin 43,Cx43)的表达明显的增加,ERK信号通路抑制剂PD98059则可以明显的抑制Cx43的表达,而甜橙黄酮与其作用相似。结论 甜橙黄酮可减轻Px-12诱导的HRGEC细胞焦亡,可能与调控ERK-MAPK/Cx43信号通路相关。     

基于NF-κB/NLRP3/Caspase-1通路介导的巨噬细胞焦亡探究葛根芩连汤对动脉粥样硬化易损斑块的干预机制

目的 探究葛根芩连汤（GQL）通过调控核转录因子（NF）-κB/NOD样受体蛋白3（NLRP3）/胱天蛋白酶（Caspase）-1通路介导的巨噬细胞焦亡对动脉粥样硬化（AS）易损斑块的作用。方法 12只正常C57BL/6CNC小鼠作为空白组，60只同品系的载脂蛋白E基因敲除（ApoE^-/-）小鼠随机分为5组，即模型组、葛根芩连汤低、中、高剂量组（GQL-D、Z、G组）、立普妥组，以高脂饲料喂养造模。空白组、模型组予等体积无菌蒸馏水灌胃；GQL-D、Z、G、立普妥组分别予对应浓度的药物灌胃8周。苏木素-伊红（HE）染色观测主动脉区域斑块情况，酶联免疫吸附测定法（ELISA）检测血清白细胞介素-1β（IL-1β）、白细胞介素-18（IL-18）水平，ELISA检测巨噬细胞甘露糖受体（MMR/CD206）/凋亡相关斑点样蛋白（ASC）、CD206/NLRP3蛋白表达水平，蛋白免疫印迹法（Western blot）检测各组小鼠gasdermin D蛋白C端（C-terminal GSDMD）、gasdermin D蛋白N端（N-terminal GSDMD）、NLRP3、含胱天蛋白酶-1前体（pro-Caspase-1）和NF-κB p65蛋白表达水平。结果 与空白组比较，模型小鼠AS病变程度严重，血清IL-1β、IL-18、组织ASC、NLRP3、C-terminal GSDMD、N-terminal GSDMD、pro-Caspase-1和NF-κB p65表达水平明显升高（P<0.05），CD206水平明显下降（P<0.05）；与模型组比较，给药各组小鼠主动脉壁AS病变程度有所减轻，血清IL-1β、IL-18、组织ASC、NLRP3、C-terminal GSDMD、N-terminal GSDMD、pro-Caspase-1和NF-κB p65表达水平有不同程度下降，CD206水平不同程度上升，部分组结果差异有统计学意义（P<0.05）。结论 GQL对AS易损斑块的干预作用可能是通过调控NF-κB/NLRP3/Caspase-1通路，减轻其介导的巨噬细胞焦亡来实现的。     

寿胎丸对脂多糖诱导的人绒毛外滋养细胞氧化应激及焦亡的调节作用

目的 探讨寿胎丸在脂多糖（LPS）诱导的人绒毛外滋养细胞（HTR-8/SVneo）损伤中的作用及其对细胞损伤中氧化应激和焦亡的调控，为寿胎丸安胎的作用机制研究提供新的方向。方法 采用LPS（100 μg?L^-1）诱导HTR-8/SVneo细胞损伤建立细胞模型，设置空白组、模型组、寿胎丸组（10%寿胎丸含药血清）、抗氧化剂组（1 mmol·L^-1 NAC）、NOD样受体热蛋白结构域3（NLRP3）抑制剂组（50 μmol·L^-1MCC950）。分别采用细胞增殖与活性检测（CCK-8）试剂盒检测细胞活性情况；Hochest 33342/PI双荧光染色和流式细胞术观察细胞死亡情况；酶联免疫吸附测定法（ELISA）检测细胞上清液中白细胞介素-18（IL-18）、白细胞介素-1β（IL-1β）、丙二醛（MDA）、超氧化物歧化酶（SOD）释放情况；DCFH-DA探针检测细胞内活性氧（ROS）含量；蛋白免疫印迹法（Western blot）检测NLRP3、胱天蛋白酶（Caspase）-1、消化道皮肤素D（GSDMD）、IL-1β蛋白的表达；实时荧光定量聚合酶链式反应（Real-time PCR）检测NLRP3、Caspase-1 mRNA的表达。结果 与空白组比较，模型组细胞活力显著降低（P<0.01），细胞上清液中炎症因子IL-1β、IL-18含量显著增加（P<0.01），氧化应激因子ROS、MDA含量升高，SOD活性显著降低（P<0.01），NLRP3、Caspase-1、GSDMD、IL-1β蛋白和NLRP3、Caspase-1 mRNA表达显著上调（P<0.01）；与模型组比较，寿胎丸组、NAC组及MCC950组细胞活力显著升高（P<0.01），寿胎丸组和NAC组MDA、ROS活性降低，SOD活性显著升高（P<0.01），寿胎丸组和MCC950组细胞上清液中IL-1β、IL-18含量减少（P<0.01），细胞内NLRP3、Caspase-1、GSDMD、IL-1β蛋白和NLRP3、Caspase-1、IL-1β mRNA表达均明显降低（P<0.05，P<0.01）。结论 寿胎丸可通过抑制氧化应激和细胞焦亡减轻LPS诱导的HTR-8/SVneo细胞损伤，这可能是寿胎丸防治复发性流产，发挥安胎作用的机制之一。     

Design and optimize N‐substituted EF24 as effective and low toxicity NF‐κB inhibitor for lung cancer therapy via apoptosis‐to‐pyroptosis switch

As NF‐κB signaling pathway is constitutively activated in lung cancer, targeting NF‐κB has a potential for the treatment. EF24 has been proved to be a NF‐κB inhibitor with good antitumor activity, while whose toxicity possibly became one of the obstacles to enter into clinical application. In order to find high efficiency and low toxicity NF‐κB inhibitors, EF24 was modified and 13d was screened out. It was proved that 13d possessed an effective combination of inhibiting NF‐κB pathway and showing lower cytotoxicity on normal cells as well as less toxicity in acute toxicity experiment compared with the lead compound of EF24. In addition, 13d was found to inhibit cell vitality, arrest cell cycle in G2/M phase, promote cell apoptosis, and suppress the xenograft tumor growth. Furthermore, 13d was elucidated to induce pyroptosis developing from apoptosis, which was associated with the inhibition of NF‐κB. Taken together, it was suggested that 13d was a potent antitumor agent.     

The regulation of the ZBP1-NLRP3 inflammasome and its implications in pyroptosis,apoptosis, and necroptosis (PANoptosis)

ZBP1 has been characterized as a critical innate immune sensor of not only viral RNA products but also endogenous nucleic acid ligands. ZBP1 sensing of the Z-RNA produced during influenza virus infection induces cell death in the form of pyroptosis, apoptosis, and necroptosis (PANoptosis). PANoptosis is a coordinated cell death pathway that is driven through a multiprotein complex called the PANoptosome and enables crosstalk and co-regulation among these processes. During influenza virus infection, a key step in PANoptosis and PANoptosome assembly is the formation of the ZBP1-NLRP3 inflammasome. When Z-RNA is sensed, ZBP1 recruits RIPK3 and caspase-8 to activate the ZBP1-NLRP3 inflammasome. Several other host factors have been found to be important for ZBP1-NLRP3 inflammasome assembly, including molecules involved in the type I interferon signaling pathway and caspase-6. Additionally, influenza viral proteins, such as M2, NS1, and PB1-F2, have also been shown to regulate the ZBP1-NLRP3 inflammasome. This review explains the functions of ZBP1 and the mechanistic details underlying the activation of the ZBP1-NLRP3 inflammasome and the formation of the PANoptosome. Improved understanding of the ZBP1-NLRP3 inflammasome will direct the development of therapeutic strategies to target infectious and inflammatory diseases.     

The NLRP1 and CARD8 inflammasomes

Inflammasomes are multiprotein complexes that activate inflammatory cytokines and induce pyroptosis in response to intracellular danger-associated signals. NLRP1 and CARD8 are related germline-encoded pattern recognition receptors that form inflammasomes, but their activation mechanisms and biological purposes have not yet been fully established. Both NLRP1 and CARD8 undergo post-translational autoproteolysis to generate two non-covalently associated polypeptide chains. NLRP1 and CARD8 activators induce the proteasome-mediated destruction of the N-terminal fragment, liberating the C-terminal fragment to form an inflammasome. Here, we review the danger-associated stimuli that have been reported to activate NLRP1 and/or CARD8, including anthrax lethal toxin, Toxoplasma gondii, Shigella flexneri and the small molecule DPP8/9 inhibitor Val-boroPro, focusing on recent mechanistic insights and highlighting unresolved questions. In addition, we discuss the recently identified disease-associated mutations in NLRP1 and CARD8, the potential role that DPP9’s protein structure plays in inflammasome regulation, and the emerging link between NLRP1 and metabolism. Finally, we summarize all of this latest research and consider the possible biological purposes of these enigmatic inflammasomes.     

细胞焦亡在肾脏炎性损伤中的作用研究进展

细胞焦亡(pyroptoysis)是由活化的caspase-1触发的一种特殊的细胞程序性死亡。肾脏细胞焦亡在肾损伤中发挥着重要的作用。GSDMD切割焦亡关键蛋白caspase-1引起下游炎性反应因子IL-18,IL-1β的成熟和释放引起肾脏炎性反应和细胞焦亡发生。本文从NLRP3激活导致肾脏炎性反应、GSDMD裂解引发细胞焦亡等角度,阐释NLRP3-caspase-1-GSDMD介导的细胞焦亡在肾脏炎性反应中的作用。