Perinatal complications,such as asphyxia,can cause brain injuries that are often associated with subsequent neurological deficits,such as cerebral palsy or mental retardation.The mechanisms of perinatal brain injury a...Perinatal complications,such as asphyxia,can cause brain injuries that are often associated with subsequent neurological deficits,such as cerebral palsy or mental retardation.The mechanisms of perinatal brain injury are not fully understood,but mitochondria play a prominent role not only due to their central function in metabolism but also because many proteins with apoptosis-related functions are located in the mitochondrion.Among these proteins,apoptosis-inducing factor has already been shown to be an important factor involved in neuronal cell death upon hypoxia-ischemia,but a better understanding of the mechanisms behind these processes is required for the development of more effective treatments during the early stages of perinatal brain injury.In this review,we focus on the molecular mechanisms of hypoxic-ischemic encephalopathy,specifically on the importance of apoptosis-inducing factor.The relevance of apoptosis-inducing factor is based not only because it participates in the caspase-independent apoptotic pathway but also because it plays a crucial role in mitochondrial energetic functionality,especially with regard to the maintenance of electron transport during oxidative phosphorylation and in oxidative stress,acting as a free radical scavenger.We also discuss all the different apoptosis-inducing factor isoforms discovered,focusing especially on apoptosis-inducing factor 2,which is only expressed in the brain and the functions of which are starting now to be clarified.Finally,we summarized the interaction of apoptosis-inducing factor with several proteins that are crucial for both apoptosis-inducing factor functions(prosurvival and pro-apoptotic)and that are highly important in order to develop promising therapeutic targets for improving outcomes after perinatal brain injury.展开更多
We report the cloning and functional characterization of human cyclin L2, a novel member of the cyclin family. Human cyclin L2 shares significant homology to cyclin L1, K, T1, T2, and C, which are involved in transcri...We report the cloning and functional characterization of human cyclin L2, a novel member of the cyclin family. Human cyclin L2 shares significant homology to cyclin L1, K, T1, T2, and C, which are involved in transcriptional regulation via phosphorylation of the C-terminal domain of RNA polymerase Ⅱ. The cyclin L2 protein contains an N-terminal "cyclin box" and C-terminal dipeptide repeats of alternating arginines and serines, a hallmark of the SR family of splicing factors. A new isoform and the mouse homologue of human cyclin L2 have also been cloned in this study. Human cyclin L2 is expressed ubiquitously in normal human tissues and tumor cells. We show here that cyclin L2 co-localizes with splicing factors SC-35 and 9G8 within nuclear speckles and that it associates with hyperphosphorylated, but not hypophosphorylated, RNA polymerase Ⅱ and CDK p110 PITSLRE kinase via its N-terminal cyclin domains. It can also associate with the SC-35 and 9G8 through its RS repeat region. Recombinant cyclin L2 protein can stimulate in vitro mRNA splicing. Overexpression of human cyclin L2 suppresses the growth of human hepatocellular carcinoma SMMC 7721 cells both in vitro and in vivo, inducing cellular apoptosis. This process involves up-regulation of p53 and Bax and decreased expression of Bcl-2. The data suggest that cyclin L2 represents a new member of the cyclin family, which might regulate the transcription and RNA processing of certain apoptosis-related factors, resulting in tumor cell growth inhibition and apoptosis.展开更多
Studies have shown that tumor necrosis factor-related apoptosis-inducing ligand（TRAIL）exhibits strong induction of apoptosis in human glioma cells.It remains unclear whether the mitochondrion pathway,an important ap...Studies have shown that tumor necrosis factor-related apoptosis-inducing ligand（TRAIL）exhibits strong induction of apoptosis in human glioma cells.It remains unclear whether the mitochondrion pathway,an important apoptosis signaling pathway,is involved in TRAIL-induced glioma cell apoptosis.In the present study,in vitro cultured human glioma U87 cells were treated with human recombinant soluble TRAIL.Apoptosis of glioma U87 cells,mitochondrial transmembrane potential（Δψm）,cytoplasmic cytochrome c concentration and changes in caspase-3,-8 and-9 activity following human recombinant soluble TRAIL treatment were investigated to determine the mechanism of glioma U87 cell apoptosis induced by TRAIL.Additionally,blocking caspase-8resulted in TRAIL-induced mitochondrion pathway activation,suggesting that TRAIL,through activating caspase-8,initiated a series of mitochondrial events and resulted in apoptosis of glioma U87 cells.展开更多
目的:分析关节腔积液中沉默信息调节因子2相关酶1(silencing information regulator 2 related enzyme 1,SIRT1),肿瘤坏死因子样弱凋亡诱导因子(tumor necrosis factor-like weak inducer of apoptosis,TWEAK)表达与膝骨关节炎的相关性...目的:分析关节腔积液中沉默信息调节因子2相关酶1(silencing information regulator 2 related enzyme 1,SIRT1),肿瘤坏死因子样弱凋亡诱导因子(tumor necrosis factor-like weak inducer of apoptosis,TWEAK)表达与膝骨关节炎的相关性。方法:选择2019年2月至2021年8月收治的103例膝骨关节患者(膝骨关节炎组),男40例,女63例,年龄(62.02±6.09)岁。根据改良Mankin评分将患者分为轻度组(Mankin评分1~4分,31例)、中度组(Mankin评分5~8分,40例)和重度组(Mankin评分≥9分,32例),另选择105例体检志愿者为对照组,男46例,女59例,年龄(62.11±6.34)岁。膝骨关节炎组检测关节腔积液和血清中SIRT1、TWEAK水平,对照组仅检测血清SIRT1、TWEAK水平。分析SIRT1、TWEAK与膝骨关节炎发生和病情的关系。结果:膝骨关节炎组关节腔积液TWEAK,血清TWEAK、C反应蛋白(C-reactive protein,CRP)、白细胞介素-6(interleukin,IL-6)、IL-1β、白细胞计数、红细胞沉降率(erythrocyte sedimentation rate,ESR)高于对照组(P<0.05),关节腔积液SIRT1、血清SIRT1低于对照组(P<0.05)。重度组关节腔积液中TWEAK水平高于中度组和轻度组(P<0.05),SIRT1低于中度组和轻度组(P<0.05)。关节腔积液中SIRT1水平与血清SIRT1水平呈正相关(P<0.05),与CRP、IL-6、IL-1β、白细胞计数、改良Mankin评分、ESR呈负相关(P<0.05);关节腔积液中TWEAK水平与血清TWEAK水平呈正相关(P<0.05),与CRP、IL-6、IL-1β、白细胞计数、改良Mankin评分、ESR呈正相关(P<0.05)。身体质量指数、从事重体力工作、关节腔积液TWEAK是膝骨关节炎发生的危险因素(P<0.05),关节腔积液SIRT1是膝骨关节炎发生的保护因素(P<0.05)。关节腔积液SIRT1、TWEAK诊断膝骨关节炎的曲线下面积(area undre curve,AUC)为0.641、0.653,联合关节腔积液SIRT1、TWEAK诊断膝骨关节炎的AUC为0.879,高于单独SIRT1、TWEAK(z=6.105、6.225,P<0.05)。结论:膝骨关节炎患者关节腔积液中SIRT1水平降低,TWEAK水平增高,低SIRT1和高TWEAK与膝骨关节炎发病以及病情加重均有关。展开更多
基金the Swedish Research Council(2018-02667)the National Natural Science Foundation of China(31761133015,U1704281,81901335)+3 种基金the Swedish Childhood Cancer Foundation(PR2018-0082)Swedish Governmental Grants to Scientists Working in Health Care(ALFGBG-717791)the Swedish Brain Foundation(FO2018-0034)the Chinese Scholarship Council to TL(201707040025)and to YX(201507040082)。
文摘Perinatal complications,such as asphyxia,can cause brain injuries that are often associated with subsequent neurological deficits,such as cerebral palsy or mental retardation.The mechanisms of perinatal brain injury are not fully understood,but mitochondria play a prominent role not only due to their central function in metabolism but also because many proteins with apoptosis-related functions are located in the mitochondrion.Among these proteins,apoptosis-inducing factor has already been shown to be an important factor involved in neuronal cell death upon hypoxia-ischemia,but a better understanding of the mechanisms behind these processes is required for the development of more effective treatments during the early stages of perinatal brain injury.In this review,we focus on the molecular mechanisms of hypoxic-ischemic encephalopathy,specifically on the importance of apoptosis-inducing factor.The relevance of apoptosis-inducing factor is based not only because it participates in the caspase-independent apoptotic pathway but also because it plays a crucial role in mitochondrial energetic functionality,especially with regard to the maintenance of electron transport during oxidative phosphorylation and in oxidative stress,acting as a free radical scavenger.We also discuss all the different apoptosis-inducing factor isoforms discovered,focusing especially on apoptosis-inducing factor 2,which is only expressed in the brain and the functions of which are starting now to be clarified.Finally,we summarized the interaction of apoptosis-inducing factor with several proteins that are crucial for both apoptosis-inducing factor functions(prosurvival and pro-apoptotic)and that are highly important in order to develop promising therapeutic targets for improving outcomes after perinatal brain injury.
文摘We report the cloning and functional characterization of human cyclin L2, a novel member of the cyclin family. Human cyclin L2 shares significant homology to cyclin L1, K, T1, T2, and C, which are involved in transcriptional regulation via phosphorylation of the C-terminal domain of RNA polymerase Ⅱ. The cyclin L2 protein contains an N-terminal "cyclin box" and C-terminal dipeptide repeats of alternating arginines and serines, a hallmark of the SR family of splicing factors. A new isoform and the mouse homologue of human cyclin L2 have also been cloned in this study. Human cyclin L2 is expressed ubiquitously in normal human tissues and tumor cells. We show here that cyclin L2 co-localizes with splicing factors SC-35 and 9G8 within nuclear speckles and that it associates with hyperphosphorylated, but not hypophosphorylated, RNA polymerase Ⅱ and CDK p110 PITSLRE kinase via its N-terminal cyclin domains. It can also associate with the SC-35 and 9G8 through its RS repeat region. Recombinant cyclin L2 protein can stimulate in vitro mRNA splicing. Overexpression of human cyclin L2 suppresses the growth of human hepatocellular carcinoma SMMC 7721 cells both in vitro and in vivo, inducing cellular apoptosis. This process involves up-regulation of p53 and Bax and decreased expression of Bcl-2. The data suggest that cyclin L2 represents a new member of the cyclin family, which might regulate the transcription and RNA processing of certain apoptosis-related factors, resulting in tumor cell growth inhibition and apoptosis.
基金the National Natural Science Foundation of China, No. 30672409the Science and Technology Foundation Program of Guangdong Province, No. 2006B36003017
文摘Studies have shown that tumor necrosis factor-related apoptosis-inducing ligand（TRAIL）exhibits strong induction of apoptosis in human glioma cells.It remains unclear whether the mitochondrion pathway,an important apoptosis signaling pathway,is involved in TRAIL-induced glioma cell apoptosis.In the present study,in vitro cultured human glioma U87 cells were treated with human recombinant soluble TRAIL.Apoptosis of glioma U87 cells,mitochondrial transmembrane potential（Δψm）,cytoplasmic cytochrome c concentration and changes in caspase-3,-8 and-9 activity following human recombinant soluble TRAIL treatment were investigated to determine the mechanism of glioma U87 cell apoptosis induced by TRAIL.Additionally,blocking caspase-8resulted in TRAIL-induced mitochondrion pathway activation,suggesting that TRAIL,through activating caspase-8,initiated a series of mitochondrial events and resulted in apoptosis of glioma U87 cells.
