Role of apoptosis-inducing factor in perinatal hypoxic-ischemic brain injury

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.

Role of TNF-related apoptosis-inducing ligand （TRAIL） in the pathogenesis of varicocele-induced testicular dysfunction

The higher frequency of varicocele in men with infertility has drawn attention and resulted in increased research at the molecular level towards treatments. The aim of this study was to investigate the role of tumor necrosis factor （TNF）-related apoptosis-inducing ligand （TRAIL） and its receptors in varicocele-induced testicular dysfunction in an experimental rat model. The rats were divided into three groups： control, sham and varicocele. Varicoceles in rats were induced by partial ligation of the left renal vein and left testes. The rats were analyzed 13 weeks after surgery. The degree of DNA fragmentation within cells in the testis was determined using terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling （TUNEL） assay. Tubule degeneration was evaluated using the Johnsen score. The expression of TRAIL and its receptors was detected by immunohistochemical and Western blotting techniques. The apoptotic index, Johnsen score and the expression of TRAIL and TRAIL receptors were examined. The data are presented as the mean-.＋s.d, and were analyzed using computer software. The KruskaI-Wallis and Dunn＇s multiple comparison tests were used in the statistical analyses. The germ cell apoptotic index was increased in rats with varicoceles when compared with the sham and control groups （P=0.0031）. The Johnsen score was significantly decreased in the varicocele group when compared with the sham and control groups （P〈O.O001）. Immunohistochemical and Western blotting analyses showed that after varicocele induction, the expression of TRAIL-R1 and TRAIL-R4 in germ cells was increased and the expression of TRAIL-R2 was decreased. There are no significant differences among the groups in terms of TRAIL and TRAIL-R3 receptor expression. The results of this study indicate that TRAIL and its receptors may have a potential role in the pathogenesis of varicocele-induced testicular dysfunction.

Relevance and therapeutic potential of Cyp A targeting to block apoptosis inducing factor-mediated neuronal cell death

Programmed cell death （PCD） signaling pathways are import- ant contributors to acute neurological insults such as hypox- ic-ischemic brain damage, traumatic brain injury, stroke etc. The pathogenesis of all these diseases is closely linked with ab- erration of apoptotic cell death pathways. Mitochondria play a crucial role during PCD, acting as both sensors of death signals, and as initiators of biochemical path- ways, which cause cell death （Bras et al., 2005）. Cytochrome c was the firstly identified apoptogenic factor released from mitochondria into the cytosol, where it induces apoptosome formation through the activation of caspases. Other proteins, such as apoptosis inducing factor （AIF）, have been subsequently identified as mitochondrial released factors. AIF contributes to apoptotic nuclear DNA damage （Bras et al., 2005）. in a caspase-independent way

Total Triterpenoids from Ganoderma Lucidum Suppresses Prostate Cancer Cell Growth by Inducing Growth Arrest and Apoptosis

In this study,one immortalized human normal prostatic epithelial cell line（BPH） and four human prostate cancer cell lines（LNCa P,22Rv1,PC-3,and DU-145） were treated with Ganoderma Lucidum triterpenoids（GLT） at different doses and for different time periods. Cell viability,apoptosis,and cell cycle were analyzed using flow cytometry and chemical assays. Gene expression and binding to DNA were assessed using real-time PCR and Western blotting. It was found that GLT dose-dependently inhibited prostate cancer cell growth through induction of apoptosis and cell cycle arrest at G1 phase. GLT-induced apoptosis was due to activation of Caspases-9 and-3 and turning on the downstream apoptotic events. GLT-induced cell cycle arrest（mainly G1 arrest） was due to up-regulation of p21 expression at the early time and down-regulation of cyclin-dependent kinase 4（CDK4） and E2F1 expression at the late time. These findings demonstrate that GLT suppresses prostate cancer cell growth by inducing growth arrest and apoptosis,which might suggest that GLT or Ganoderma Lucidum could be used as a potential therapeutic drug for prostate cancer.

Antitumor effect of tumor necrosis factor-related apoptosis inducing ligand combined with mevastatin on a human glioma cell line SWO-38

BACKGROUND： Previous studies have reported that statins are less toxic to the human body and have greater antitumor activity; however, few studies have addressed the antitumor effect of statins combined with tumor necrosis factor-related apoptosis inducing ligand （TRAIL）. OBJECTIVE： To explore the effect of TRAIL combined with mevastatin on the proliferation and apoptotic cell death of a human glioma cell line SWO-38, and to study its mechanism of action. DESIGN, TIME AND SETTING： An in vitro control experiment was performed at the Central Laboratory of the Third Hospital Affiliated to Sun Yat-sen University, between January and April 2009. MATERIALS： The human SWO-38 cell line was provided by Cell Research, Department of Animal Experimental Center of Sun Yat-sen University; human recombinant soluble TRAIL by R＆D, USA; and mevastatin by Sigma, USA. METHODS： SWO-38 cells were separately incubated in TRAIL （100, 200, 300, 400, and 500 tJg/L） and mevastatin （5, 10, 20, 30, and 40 pmol/L） for 72 hours. In addition, SWO-38 cells were incubated in TRAIL （300 μg/L）, mevastatin （30 μmol/L）, and a solution containing both TRAIL and mevastatin for 12, 24, 48 and 72 hours. MAIN OUTCOME MEASURES： Cell proliferation was detected using methyl thiazolyl tetrazolium assay; cell apoptosis was observed using Hoechst 33258 staining and fluorescence microscopy and was measured using Annexin V/propidium iodide flow cytometry; TRAIL R1/DR4 and TRAIL R2/DR5 protein expressions levels were measured using indirect immunofluorescence staining combined with flow cytometry in the recombinant soluble TRAIL （rsTRAIL, 300 tJg/L）, mevastatin （30 IJmol/L） and combination groups; TRAIL R1/DR4 and TRAIL R2/DR5 mRNA expression was detected using real-time polymerase chain reaction. RESULTS： rsTRAIL, mevastatin and their combination inhibited tumor proliferation in a time- and dose-dependent manner. The proliferation inhibitory rate and apoptosis rate of human SWO-38 cells in the combined group were significantly greater than the rsTRAIL or mevastatin alone group （P 〈 0.01）. TRAIL R1/DR4 and TRAIL R2/DR5 protein and mRNA expressions were increased in the combination group compared with mevastatin or rsTRAIL alone after 72 hours （P 〈 0.01）. CONCLUSION： Both rsTRAIL and mevastatin inhibit the proliferation and apoptosis of the human glioma cell line SWO-38, while their combination enhances the anti-tumor effect. The mechanism of action possibly correlates to the upregulation of TRAIL R1/DR4 and TRAIL R2/DR5 mRNA expression by mevastatin, thereby enhancing the cell sensitivity to rsTRAIL.

Expression of tumor necrosis factor related apoptosis inducing ligand receptor in glioblastoma

BACKGROUND： Receptors for tumor necrosis factor related apoptosis inducing ligand （TRAIL） include death receptor 4, death receptor 5, decoy receptor 1, and decoy receptor 2. Activation of death receptor 4 and 5 selectively kills tumor cells. OBJECTIVE： To detect TRAIL receptor expression in glioblastoma by immunohistochemistry and RT-PCR, and to compare this expression to that in normal brain tissue. DESIGN： Observational analysis. SETTING： Department of Pathology, the First Affiliated Hospital of Zhengzhou University; Henan Tumor Pathology Key Laboratory. PARTICIPANTS： Twenty-five patients （17 males and 8 females） who received glioblastoma resection were selected from the Fifth Affiliated Hospital of Zhengzhou University, between September 2003 to June 2004. All glioblastoma samples were diagnosed pathologically. Twenty patients （12 males and 8 females） with craniocerebral injury who received normal brain tissue resection were selected in the same time period. There were no significant differences in sex and age between glioblastoma patients or between craniocerebral injury patients （P 〉 0.05）. All patients and appropriate relatives provided informed consent, and this study was approved by the local research ethics committee. METHODS： Polyclonal antibody against TRAIL receptors and an immunohistochemical kit （batch number： 200502） were purchased from Boster Company, Wuhan. Immunohistochemistry： Expression of death receptor 4, death receptor 5, decoy receptor l, and decoy receptor 2 were observed in both glioblastoma and normal brain tissue. The experiment was performed according to the kit instructions, and positive staining was brown-yellow. Assessment： There were no positive signals （-）; weakly positive signals, positive cells 〈 25% （＋）; weakly positive signals, positive cells 25%-50% （＋＋）; strongly positive signals, positive cells 50%-75% （＋＋＋）; strongly positive signals, positive cells 〉 75% （＋＋＋＋）. Evaluation： Expression levels of TRAIL receptors were estimated in both normal brain tissue and glioblastoma. Expression of decoy receptor 1 and decoy receptor 2 mRNA in glioblastoma were detected by reverse transcription polymerase chain reaction, and expression of decoy receptor in glioblastoma was estimated. MAIN OUTCOME MEASURES： Comparison of death receptor and decoy receptor protein expression between glioblastoma and normal brain tissue; decoy receptor mRNA expression in glioblastoma. RESULTS： Death receptor protein expression was strongly positive （＋＋＋） in glioblastoma, while it was weakly positive （＋, ＋＋） in normal brain tissue. Therefore, expression rate of death receptor protein in the glioblastoma was significantly higher than that in the normal brain tissue （.~ 2 = 18.48, 23.03, P 〈 0.01）. Decoy receptor protein expression in the glioblastoma was significantly lower than that in the normal brain tissue （ x2 = 6.65, 18.76, P 〈 0.01）. The level of decoy receptor mRNA expression in glioblastoma was significantly higher than those of protein expression （ x 2 = 9.82, 10.09, P〈 0.01）. CONCLUSION： High expression of death receptor and low expression of decoy receptor are frequently observed in glioblastoma, suggesting that TRAIL receptor genes show an anti-tumor and expressive response during the initiation and development of the tumor. There are significant differences in decoy receptor expression between normal brain tissue and glioblastoma, suggesting that the restricted expression of decoy receptor in glioblastoma is regulated at the post-transcriptional level.

COMBINATION OF γ-INTERFERON WITH TRAIL AND CISPLATIN OR ETOPOSIDE INDUCES APOPTOSIS IN HUMAN NEUROBLASTOMA CELL LINE SH-SY5Y

Objective To study the effect of γ-interferon （IFNγ）, tumor necrosis factor related apoptosis inducing ligand （TRAIL）, and cisplatin or etoposide induced apoptosis in human neuroblastoma cell line SH-SY5Y and its possible molecular mechanisms. Methods The expressions of Caspase 8 mRNA and protein were detected with RT-PCR and Western blot analysis. The effects of IFNγ, TRAIL, IFNγ ＋ TRAIL, IFNγ ＋ Caspase 8 inhibitor ＋ TRAIL, IFNγ ＋ cisplatin ＋ TRAIL, and IFNγ ＋ etoposide ＋ TRAIL on the growth and apoptosis of SH-SY5Y cells were detected with the methods of MTT and flow cytometry. The relative Caspase 8 activity was measured with colorimetric assay. Results Caspase 8 was undetectable in SH-SY5Y cells but an increased expression of Caspase 8 mRNA and protein was found after treatment with IFNγ. SH-SY5Y ceils themselves were not sensitive to TRAIL, but those expressing Caspase 8 after treatment with IFNγ were. The killing effect of TRAIL on SH-SY5Y cells expressing Caspase 8 was depressed by Caspase 8 inhibitor. Cisplatin and etoposide could enhance the sensitivity of TRAIL on SH-SY5Y cells. The relative Caspase 8 activity of SH-SY5Y cells in IFNγ ＋ TRAIL group was significantly higher than those of control group, IFNγ group, TRAIL group, and inhibitor group （ P 〈 0. 01 ）. There was no significant difference among IFNγ ＋ TRAIL group, IFNγ ＋ cisplatin ＋ TRAIL group, and IFNγ ＋ etoposide ＋ TRAIL group. Conclusions IFNγ could sensitize SH-SY5Y cells to TRAIL-induced apoptosis and this may be realized by the up-regulation of Caspase 8. Cisplatin and etoposide could enhance the killing effect of TRAIL on SH-SY5Y cells.

Loss of the vitamin D receptor in human breast and prostate cancers strongly induces cell apoptosis through downregulation of Wnt/β-catenin signaling

Vitamin D co-regulates cell proliferation, differentiation and apoptosis in numerous tissues, including cancers. The known anti-proliferative and pro-apoptotic actions of the active metabolite of vitamin D, 1,25-dihydroxy-vitamin D [1,25（OH）2D] are mediated through binding to the vitamin D receptor （VDR）. Here, we report on the unexpected finding that stable knockdown of VDR expression in the human breast and prostate cancer cell lines, MDA-MB-231 and PC3, strongly induces cell apoptosis and inhibits cell proliferation in vitro. Implantation of these VDR knockdown cells into the mammary fat pad （MDA-MB-231）, subcutaneously （PC3） or intra-tibially （both cell lines） in immune-incompetent nude mice resulted in reduced tumor growth associated with increased apoptosis and reduced cell proliferation compared with controls. These growth-retarding effects of VDR knockdown occur in the presence and absence of vitamin D and are independent of whether cells were grown in bone or soft tissues. Transcriptome analysis of VDR knockdown and non-target control cell lines demonstrated that loss of the VDR was associated with significant attenuation in the Wnt/0-catenin signaling pathway. In particular, cytoplasmic and nuclear β-catenin protein levels were reduced with a corresponding downregulation of downstream genes such as Axin2, Cyclin D1, interleukin-6 （IL-6）, and IL-8. Stabilization of 0-catenin using the GSK-3β inhibitor BIO partly reversed the growth-retarding effects of VDR knockdown. Our results indicate that the unliganded VDR possesses hitherto unknown functions to promote breast and prostate cancer growth, which appear to be operational not only within but also outside the bone environment. These novel functions contrast with the known anti-proliferative nuclear actions of the liganded VDR and may represent targets for new diagnostic and therapeutic approaches in breast and prostate cancer.

TRAIL-induced apoptosis of hepatocellular carcinoma cells is augmented by targeted therapies

AIM:To analyze the effect of chemotherapeutic drugs and specific kinase inhibitors,in combination with the death receptor ligand tumor necrosis factor-related apoptosis inducing ligand(TRAIL),on overcoming TRAIL resistance in hepatocellular carcinoma(HCC)and to study the efficacy of agonistic TRAIL antibodies,as well as the commitment of antiapoptotic BCL-2 proteins, in TRAIL-induced apoptosis. METHODS:Surface expression of TRAIL receptors (TRAIL-R1-4)and expression levels of the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL were analyzed by flow cytometry and Western blotting,respectively. Knock-down of MCL-1 and BCL-xL was performed by transfecting specific small interfering RNAs.HCC cellswere treated with kinase inhibitors and chemotherapeutic drugs.Apoptosis induction and cell viability were analyzed via flow cytometry and 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS:TRAIL-R1 and-R2 were profoundly expressed on the HCC cell lines Huh7 and Hep-G2. However,treatment of Huh7 and Hep-G2 with TRAIL and agonistic antibodies only induced minor apoptosis rates.Apoptosis resistance towards TRAIL could be considerably reduced by adding the chemotherapeutic drugs 5-fluorouracil and doxorubicin as well as the kinase inhibitors LY294002[inhibition of phosphoinositol- 3-kinase(PI3K)],AG1478(epidermal growth factor receptor kinase),PD98059(MEK1),rapamycin(mam- malian target of rapamycin)and the multi-kinase inhibitor Sorafenib.Furthermore,the antiapoptotic BCL-2 proteins MCL-1 and BCL-xL play a major role in TRAIL resistance:knock-down by RNA interference increased TRAIL-induced apoptosis of HCC cells.Additionally, knock-down of MCL-1 and BCL-xL led to a significant sensitization of HCC cells towards inhibition of both c-Jun N-terminal kinase and PI3K.CONCLUSION:Our data identify the blockage of survival kinases,combination with chemotherapeutic drugs and targeting of antiapoptotic BCL-2 proteins as promising ways to overcome TRAIL resistance in HCC.

Apoptosis and Expression of Protein TRAIL in Granulosa Cells of Rats with Polycystic Ovarian Syndrome

The relationship between apoptosis of granulosa cells and follicle development arrest in polycystic ovarian syndrome (PCOS) rats, and the contribution of tumor necrosis factor related apoptosis inducing ligand (TRAIL) in apoptosis of granulosa cells were explored. By using sodium prasterone sulfate rat PCOS model was induced. The apoptosis of granulosa cells in ovaries of rats was observed by TdT-mediated dUTP-biotin nick end-labeling (TUNEL), and the expression of TRAIL protein and mRNA in granulosa cells was detected by using immunhistochemical staining and reverse transcription polymerase chain reaction (RT-PCR) respectively. The apoptotic rate and the expression of protein TRAIL in granulosa cells were significantly higher in antral follicles from the PCOS rats than in those from the control rats (P<0.01, P<0.05). There was no significant difference in apoptotic rate and the expression of TRAIL protein in granulosa cells of preantral follicles between the PCOS rats and the control rats (P>0.05). No apoptosis and the expression of TRAIL protein in granulosa cells of primordial follicles were found in the two groups. The expression of TRAIL mRNA was significantly stronger in granulosa cells from the PCOS rats than in those from the con- trol rats (P<0.01). It was suggested that the apoptotic rate in granulosa cells was significantly higher in antral follicle from the PCOS rats than in those from the control rats. TRAIL played a role in regu- lating the apoptosis of granulosa cells in PCOS rats.

Inactivated Sendai Virus Induces Apoptosis in Murine Melanoma Cells by IGF-1R Down-regulation

The mortality of cancer patients has considerably improved due to progress in surgery, chemotherapy and radiotherapy. However, some types of cancers, such as melanoma, remain refractory to conventional strategies. Although melanoma accounts for only 4% of all dermatological malignancies, it is responsible for 80% of mortalities from skin tumors[11. The reported survival rate of melanoma over 5 years is not yet encouraging due to its chemo-resistance and rapid metastasis. Therefore, it is necessary to develop new drugs with potent activity and weak side-effect against melanoma.

Chloride channel blocker 4,4-diisothiocyanatostilbene-2,2'-disulfonic acid inhibits nitric oxide-induced apoptosis in cultured rat hippocampal neurons

Apoptosis in cultured rat hippocampal neurons was induced using the nitric oxide donor 3-morpholinosydnonimine, and cells were treated with the chloride channel blocker, 4,4- diisothiocyanatostilbene-2,2＇-disulfonic acid. Results showed that the survival rate of neurons was significantly increased after treatment with 4,4-diisothiocyanatostilbene-2,2＇-disulfonic acid, and the rate of apoptosis decreased. In addition, the expression of the apoptosis-related proteins poly（adenosine diphosphate-ribose）polymerase-1 and apoptosis-inducing factor were significantly reduced. Our experimental findings indicate that the chloride channel blocker 4,4- diisothiocyanatostilbene-2,2＇-disulfonic acid can antagonize apoptotic cell death of hippocampal neurons by inhibiting the expression of the apoptosis-related proteins poly（adenosine diphosphate-ribose）polymerase-1 and apoptosis-inducing factor.

LncRNA LUCAT1 Activation Mediated by theDown-regulation of DNMT1 Is Involved inCell Apoptosis Induced by PM2.5

Particulate matter （PM）, which is a great environmental concern, has been classified as a Group 1 human carcinogen by the International Agency for Research on Cancer （IARC）;.Epidemiological and experimental studies have indicated that chronic exposure to PM, especially PM;(particles with an aerodynamic diameter less than

Kinetin Inhibits Proliferation of Hepatic Stellate Cells by Interrupting Cell Cycle and Induces Apoptosis by Down-regulating Ratio of Bcl-2/Bax

Liver fibrosis is an important health problem that can further progress into cirrhosis or liver cancer,and result in significant morbidity and mortality. Inhibiting proliferation and inducing apoptosis of hepatic stellate cells（HSCs） may be the key point to reverse liver fibrosis. At present,anti-fibrosis drugs are rare. Kinetin is a type of plant-derived cytokinin which has been reported to control differentiation and induce apoptosis of human cells. In this study,the HSCs were incubated with different concentrations of kinetin. The proliferation of rat HSCs was measured by MTT assay,cell cycle and apoptosis were analyzed by flow cytometry,and the apoptosis was examined by TUNEL method. The expression of Bcl-2 and Bax proteins was detected by immunocytochemistry staining. It was found that kinetin could markedly inhibit proliferation of HSCs. In a concentration range of 2 to 8 μg/m L,the inhibitory effects of kinetin on proliferation of HSCs were increased with the increased concentration and the extension of time（P〈0.01）. Flow cytometry indicated that kinetin could inhibit the DNA synthesis from G0/G1 to S phase in a dose-dependent manner（P〈0.01）. The apoptosis rates of the HSCs treated with 8,4 and 2 μg/m L kinetin（25.62%±2.21%,15.31%±1.9% and 6.18%±1.23%,respectively） were increased significantly compared with the control group（3.81%±0.93%）（P〈0.01）. All the DNA frequency histogram in kinetin-treated groups showed obvious hypodiploid peak（sub-G1 peak）,and with the increase of kinetin concentrations,the apoptosis rate of HSCs also showed a trend of increase. It was also found that kinetin could down-regulate the expression of Bcl-2,and up-regulate the expression of Bax,leading to the decreased ratio of Bcl-2/Bax significantly. The kinetin-induced apoptosis of HSCs was positively correlated with the expression of Bax,and negatively with the expression of Bcl-2. It was concluded that kinetin can inhibit activation and proliferation of HSCs by interrupting the cell cycle at G1/S restriction point and inducing apoptosis of HSCs via reducing the ratio of Bcl-2/Bax.

Cyclin L2, a novel RNA polymerase Ⅱ-associated cyclin, is involved in pre-mRNA splicing and induces apoptosis of human hepatocellular carcinoma cells

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.

Brain edema and tumor necrosis factor-like weak inducer of apoptosis in rats with cerebral ischemia

BACKGROUND： Recent studies have demonstrated that tumor necrosis factor-like weak inducer of apoptosis （TWEAK） participates in brain edema. However, it is unclear whether blood-brain barrier （BBB） disruption is associated with TWEAK during the process of brain edema OBJECTIVE： To investigate the effects of TWEAK on BBB permeability in brain edema. DESIGN, TIME AND SETTING： An immunohistochemical observation, randomized, controlled animal experiment was performed at the Laboratory of Neurosurgical Anatomy, Xiangya Medical College, Central South University ＆ Central Laboratory, Third Xiangya Hospital, Central South University between January 2006 and December 2007. MATERIALS： A total of 48 adult Wistar rats were randomly divided into three groups： normal control （n = 8）, sham-operated （n = 8）, and ischemia/reperfusion （n = 32）. Rats from the ischemia/reperfusion group were randomly assigned to four subgroups according to different time points, i.e., 2 hours of ischemia followed by 6 hours （n = 8）, 12 hours （n = 8）, 1 day （n = 8）, or 12 days （n = 8） of reperfusion. METHODS： Focal cerebral ischemia/reperfusion injury was induced by middle cerebral artery occlusion （MCAO） using the suture method in rats from the ischemia/reperfusion group. Thread was introduced at a depth of 17-19 mm. Rats in the sham-operated group were subjected to experimental procedures similar to the ischemia/reperfusion group; however, the introducing depth of thread was 10 mm. The normal control group was not given any intervention. MAIN OUTCOME MEASURES： TWEAK expression was examined by immunohistochemistry; brain water content on the ischemic side was calculated as the ratio of dry to wet tissue weight; BBB permeability was measured by Evans blue extravasation. RESULTS： A total of eight rats died prior to and after surgery and an additional eight rats were randomly entered into the study. Thus 48 rats were included in the final analysis. In the ischemia/reperfusion group, TWEAK-positive cells were present in the ischemic penumbra surrounding the lamellar necrotic region in the fight cerebral hemisphere at 6 hours reperfusion and increased thereafter; by 2 days reperfusion they had reached a peak level, which was significantly higher than the sham-operated and normal control groups （P 〈 0.05）. At 6 hours reperfusion, both brain water content and Evans blue extravasation showed the same tendency for change as TWEAK expression. Pearson correlation analysis results revealed that the degree of TWEAK expression was positively correlated with brain water content （r = 0.892, P 〈 0.05）. CONCLUSION： The present results confirmed that TWEAK was involved in BBB disruption and participated in brain edema following cerebral ischemia.

Role of alpha-synuclein in neuronal apoptosis induced by rotenone

BACKGROUND： Aggregation of α-synuclein is the major component of Lewy bodies, which are the pathological hallmarks of Parkinson disease （PD）. Although the mechanism of this protein aggregates is unclear, previous study showed that environmental toxins such as rotenone could induce the expression and aggregation of α-synuclein. OBJECTIVE： To observe the role of α-synuclein in PD.DESIGN ： A randomized controlled trial.SETTING ： Beijing Institute for Neuroscience, Capital University of Medical Sciences.MATERIALS ： This study was performed from July 2005 to January 2006 at the Beijing Institute for Neuroscience, Capital University of Medical Sciences. Human dopaminergic neuroblastoma SH-SY5Y cells were provided by Beijing Institute for Neuroscience, Capital University of Medical Sciences. METHODS： Human dopaminergic neuroblastoma SH-SY5Y cells were treated to make α-synuclein over express. Rotenone was added into the medium of cultured both native SH-SY5Y cells and α-synuclein-overexpression SH-SY5Y cells. Lactate dehydrogenase （LDH） assay was used to detect with the cell viability. Flow cytometry and electrophoresis were adopted to measure the cell apoptosis. MAIN OUTCOME MEASURES ： Cell viability, DNA fragmentation, and the number of cell apoptosis.RESULTS： After being treated with rotenone, LDH activity of α-synuclein overexpressed SH-SY5Y cells was （76.625±6.34） μkat/L, which was significantly lower than that of control group （P 〈 0.05）. As compared with normal SH-SY5Y cell, α-synuclein over-expressed SH-SY5Y cells had less DNA fragments and apoptotic cells, α-synuclein might play a role in cell apoptosis induced by rotenone, which was also confirmed by using of antioxidant reagent. CONCLUSION： α-synuclein may partially protect against cell apoptosis induced by rotenone in SH-SY5Y cells.

Apoptosis Induced by Zinc Deficiency in Rat Osteoblast:Possible Involvement of Protein Kinase C

Ra ostcobasts were isolated from the 21-day fetal rat calvchas. The cells were grown in DMEM Plus 10% FBS, and were treated for 24 h. with 10 μmol/L TPEN or 10 μmol/L TPEN supplemented with 10 μmol/L Zn2+. Apoptosis of osteoblasts were measured by fiow cytometry, electron microscopy and DNA fragmentation analyzed by gel elecmphoresis. In addition, IP3 production and PKC activity were measmed in ordr to show whether they are involved in apoptosis in osteoblast induced by alnc deficiency. The results showed that 10 μmol/L TPEN could induce apoptosis in osteoblast in 24 h. But cells ed with 10μmol/L TPEN supplemented with 10 μmol/L Zn2+ showed no apoptotic changs in 24 h. TPEN significantly reduced the formation of IP3 and PKC activity after 24 h incubation. No differences were observed between the cells treated with TPEN supPlemented with Zn2+ simulaneosly and the untreated cells. It can be inferred that apoptosis induced by ainc deficiency may be due to the decreased activity of PKC which is impaired by reduced formation of IP3.

Effect and mechanism of adrenomedullin on apoptosis of renal tubular epithelial cell in rats induced by renal ischemia reperfusion injury

Objective To investigate the effect and mechanism of adrenomedullin ( AM ) on apoptosis of renal tubular epithelial cell in rats induced by renal ischemia reperfusion injury. Methods Thirty-two Wistar rats were randomly divided into 4 groups: control group,IRI group, empty plasmid group and AM group. One week after re-

Effects of 3-aminobenzamide on expressions of poly（ADP ribose） polymerase and apoptosis inducing factor in cardiomyocytes of rats with acute myocardial infarction

Background Poly（ADP-ribose） polymerase （PARP） plays an important role in cell survival and death. However, the mechanisms involved are not fully understood. Therefore, we investigated the effect of inhibition of PARP on acute myocardial infarction （AMI） at different time points in rats. Methods AMI was induced in rats by ligating the left anterior descending coronary artery. One group received 3-aminobenzamide （3-AB, a kind of PARP inhibitor） （30 mg/kg） by intraperitoneal injection. The changes of ultramicrostructure of cardiocytes in infarction region were noted, PARP cleavage was measured by Western blotting, and expressions of protein of PARP and apoptosis inducing factor （AIF） were measured by immunohistochemical staining after treatment with 3-AB for 2 hours, 4 hours, 6 hours, 1 week, 4 weeks and 8 weeks. Results Few damages to the ultramicrostructure of cardiocytes were observed after treatment with 3-AB. PARP cleavage was detected as early as 4 hours and markedly increased by 6 hours following AMI without 3-AB, but was not found until 6 hours following AMI treated with 3-AB. There were significant differences between 3-AB and AMI groups at the same time points. The expression of PARP was observed gradually increased, but that of AIF was suppressed for 6 hours after treatment of 3-AB, compared with AMI groups in positive cells at the same time points. There was significantly less cleavage of PARP and more PARP expression in 3-AB treated group compared with AMI and control groups at all matched time points. Conclusions Our results suggest that 3-AB inhibits degradation of PARP, increases the expression of PARP protein, and suppresses the expression of AIF protein. Inhibition of PARP activity may protect cardiocytes in rats with AMI and reduce apoptosis.