Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different...Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.展开更多
Noise-induced hearing loss is the primary non-genetic factor contributing to auditory dysfunction.However,there are currently no effective pharmacological interventions for patients with noise-induced hearing loss.Her...Noise-induced hearing loss is the primary non-genetic factor contributing to auditory dysfunction.However,there are currently no effective pharmacological interventions for patients with noise-induced hearing loss.Here,we present evidence suggesting that the lysine-specific demethylase 1 inhibitor–tranylcypromine is an otoprotective agent that could be used to treat noise-induced hearing loss,and elucidate its underlying regulatory mechanisms.We established a mouse model of permanent threshold shift hearing loss by exposing the mice to white broadband noise at a sound pressure level of 120 d B for 4 hours.We found that tranylcypromine treatment led to the upregulation of Sestrin2(SESN2)and activation of the autophagy markers light chain 3B and lysosome-associated membrane glycoprotein 1 in the cochleae of mice treated with tranylcypromine.The noise exposure group treated with tranylcypromine showed significantly lower average auditory brainstem response hearing thresholds at click,4,8,and 16 k Hz frequencies compared with the noise exposure group treated with saline.These findings indicate that tranylcypromine treatment resulted in increased SESN2,light chain 3B,and lysosome-associated membrane glycoprotein 1 expression after noise exposure,leading to a reduction in levels of 4-hydroxynonenal and cleaved caspase-3,thereby reducing noise-induced hair cell loss.Additionally,immunoblot analysis demonstrated that treatment with tranylcypromine upregulated SESN2 expression via the autophagy pathway.Tranylcypromine treatment also reduced the production of NOD-like receptor family pyrin domaincontaining 3(NLRP3)production.In conclusion,our results showed that tranylcypromine treatment ameliorated cochlear inflammation by promoting the expression of SESN2,which induced autophagy,thereby restricting NLRP3-related inflammasome signaling,alleviating cochlear hair cell loss,and protecting hearing function.These findings suggest that inhibiting lysine-specific demethylase 1 is a potential therapeutic strategy for preventing hair cell loss and noise-induced hearing loss.展开更多
目的:检测炎性复合体隐热蛋白(NLR family,pyrin domain containing 3,NLRP3)、凋亡相关斑点样蛋白(apoptosis associated speck like protein containing a CRAD,ASC)及黑色素瘤缺乏因子2(absent in melanoma 2,AIM2)在急性白血病患者...目的:检测炎性复合体隐热蛋白(NLR family,pyrin domain containing 3,NLRP3)、凋亡相关斑点样蛋白(apoptosis associated speck like protein containing a CRAD,ASC)及黑色素瘤缺乏因子2(absent in melanoma 2,AIM2)在急性白血病患者血浆中的表达水平,并探究其意义。方法:收集2013年7月至2014年7月赣南医学院第一附属医院血液科住院的19例急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)和41例急性非淋巴细胞白血病(acute non-lymphocytic leukemia,ANLL)共60例AL患者(AL组)以及同期20例非恶性血液病患者(对照组)外周血液标本,其中AL组又分为急性白血病初治组、复发组及缓解组各20例。采用酶联免疫吸附剂测定法(enzymelinked immunosorbnent assay,ELISA)检测外周血血浆中NLRP3、ASC及AIM2的表达水平。结果:NLRP3、ASC及AIM2在对照组及AL缓解组患者血浆中表达水平显著高于初治组及复发组,差异有统计学意义(P<0.05)。在ALL与ANLL组表达差异无统计学意义(P>0.05)。结论:炎性复合体在AL患者中表达受抑,可能起到了抗白血病免疫的作用。对炎性复合体的检测可能为急性白血病的早期诊断和疗效判定提供实验室依据。展开更多
基金supported by the National Natural Science Foundation of China(U22A20520)the Innovation Team Project of Modern Agricultural Industrial Technology System of Guangdong Province,China(2023KJ119)the Natural Science Foundation Program of Guangdong Province,China(2023A1515012206)。
文摘Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.
基金supported by the National Key Research and Development Program of China,No.2022YFC2402701(to WC)Key International(Regional)Joint Research Program of the National Natural Science Foundation of China,No.81820108009(to SY)+5 种基金the National Natural Science Foundation of China,Nos.81970890(to WC)and 82371148(to WG)Fujian Provincial Healthcare Young and Middle-aged Backbone Talent Training Project,No.2023GGA035(to XC)Spring City Planthe High-level Talent Promotion and Training Project of Kunming,No.2022SCP001(to SY)the Natural Science Foundation of Hainan Province of China,No.824MS052(to XS)the Sixth Medical Center of Chinese PLA General Hospital Innovation Cultivation,No.CXPY202116(to LX)。
文摘Noise-induced hearing loss is the primary non-genetic factor contributing to auditory dysfunction.However,there are currently no effective pharmacological interventions for patients with noise-induced hearing loss.Here,we present evidence suggesting that the lysine-specific demethylase 1 inhibitor–tranylcypromine is an otoprotective agent that could be used to treat noise-induced hearing loss,and elucidate its underlying regulatory mechanisms.We established a mouse model of permanent threshold shift hearing loss by exposing the mice to white broadband noise at a sound pressure level of 120 d B for 4 hours.We found that tranylcypromine treatment led to the upregulation of Sestrin2(SESN2)and activation of the autophagy markers light chain 3B and lysosome-associated membrane glycoprotein 1 in the cochleae of mice treated with tranylcypromine.The noise exposure group treated with tranylcypromine showed significantly lower average auditory brainstem response hearing thresholds at click,4,8,and 16 k Hz frequencies compared with the noise exposure group treated with saline.These findings indicate that tranylcypromine treatment resulted in increased SESN2,light chain 3B,and lysosome-associated membrane glycoprotein 1 expression after noise exposure,leading to a reduction in levels of 4-hydroxynonenal and cleaved caspase-3,thereby reducing noise-induced hair cell loss.Additionally,immunoblot analysis demonstrated that treatment with tranylcypromine upregulated SESN2 expression via the autophagy pathway.Tranylcypromine treatment also reduced the production of NOD-like receptor family pyrin domaincontaining 3(NLRP3)production.In conclusion,our results showed that tranylcypromine treatment ameliorated cochlear inflammation by promoting the expression of SESN2,which induced autophagy,thereby restricting NLRP3-related inflammasome signaling,alleviating cochlear hair cell loss,and protecting hearing function.These findings suggest that inhibiting lysine-specific demethylase 1 is a potential therapeutic strategy for preventing hair cell loss and noise-induced hearing loss.
