scholarly journals Curcumin Enhanced Busulfan-Induced Apoptosis through Downregulating the Expression of Survivin in Leukemia Stem-Like KG1a Cells

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Guangyang Weng ◽  
Yingjian Zeng ◽  
Jingya Huang ◽  
Jiaxin Fan ◽  
Kunyuan Guo
Keyword(s):  
Specific Inhibitor ◽  
Annexin V ◽  
Chemotherapeutic Agents ◽  
Combination Group ◽  
Hematopoietic Stem ◽  
Leukemia Relapse ◽  
Conditioning Regimens ◽  
Underlying Mechanisms ◽  
Induced Apoptosis ◽  
Related Proteins

Leukemia relapse and nonrecurrence mortality (NRM) due to leukemia stem cells (LSCs) represent major problems following hematopoietic stem cell transplantation (HSCT). To eliminate LSCs, the sensitivity of LSCs to chemotherapeutic agents used in conditioning regimens should be enhanced. Curcumin (CUR) has received considerable attention as a result of its anticancer activity in leukemia and solid tumors. In this study, we investigated the cytotoxic effects and underlying mechanisms in leukemia stem-like KG1a cells exposed to busulfan (BUS) and CUR, either alone or in combination. KG1a cells exhibiting BUS-resistance demonstrated by MTT and annexin V/propidium iodide (PI) assays, compared with HL-60 cells. CUR induced cell growth inhibition and apoptosis in KG1a cells. Apoptosis of KG1a cells was significantly enhanced by treatment with CUR+BUS, compared with either agent alone. CUR synergistically enhanced the cytotoxic effect of BUS. Seven apoptosis-related proteins were modulated in CUR- and CUR+BUS-treated cells analyzed by proteins array analysis. Importantly, the antiapoptosis protein survivin was significantly downregulated, especially in combination group. Suppression of survivin with specific inhibitor YM155 significantly increased the susceptibility of KG1a cells to BUS. These results demonstrated that CUR could increase the sensitivity of leukemia stem-like KG1a cells to BUS by downregulating the expression of survivin.

scholarly journals Anthracycline-induced cytotoxicity in the GL261 glioma model system

2021 ◽  
Author(s):  
Amber M. Tavener ◽  
Megan C. Phelps ◽  
Richard L. Daniels
Keyword(s):  
Cell Viability ◽  
Tumor Cells ◽  
Flow Cytometric Analysis ◽  
Annexin V ◽  
Chemotherapeutic Agents ◽  
Cytotoxic Effects ◽  
High Concentrations ◽  
Induced Apoptosis ◽  
Dose Dependent ◽  
Gl261 Glioma

AbstractGlioblastoma (GBM) is a lethal astrocyte-derived tumor that is currently treated with a multi-modal approach of surgical resection, radiotherapy, and temozolomide-based chemotherapy. Alternatives to current therapies are urgently needed as its prognosis remains poor. Anthracyclines are a class of compounds that show great potential as GBM chemotherapeutic agents and are widely used to treat solid tumors outside the central nervous system. Here we investigate the cytotoxic effects of doxorubicin and other anthracyclines on GL261 glioma tumor cells in anticipation of novel anthracycline-based CNS therapies. Three methods were used to quantify dose-dependent effects of anthracyclines on adherent GL261 tumor cells, a murine cell-based model of GBM. MTT assays quantified anthracycline effects on cell viability, comet assays examined doxorubicin genotoxicity, and flow cytometry with Annexin V/PI staining characterized doxorubicin-induced apoptosis and necrosis. Dose-dependent reductions in GL261 cell viability were found in cells treated with doxorubicin (EC50 = 4.9 μM), epirubicin (EC50 = 5.9 μM), and idarubicin (EC50 = 4.4 μM). Comet assays showed DNA damage following doxorubicin treatments, peaking at concentrations of 1.0 μM and declining after 25 μM. Lastly, flow cytometric analysis of doxorubicin-treated cells showed dose-dependent induction of apoptosis (EC50 = 5.2 μM). Together, these results characterized the cytotoxic effects of anthracyclines on GL261 glioma cells. We found dose-dependent apoptotic induction; however at high concentrations we find that cell death is likely necrotic. Our results support the continued exploration of anthracyclines as compounds with significant potential for improved GBM treatments.

Multiple Signal Pathways Involved in Crocetin-Induced Apoptosis in KYSE-150 Cells

Pharmacology ◽  
2019 ◽  
Vol 103 (5-6) ◽  
pp. 263-272 ◽  
Author(s):  
Sheng Li ◽  
Yuhua Qu ◽  
Xiu-Yin Shen ◽  
Ting Ouyang ◽  
Wen-Bin Fu ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Squamous Carcinoma ◽  
Annexin V ◽  
Signal Pathways ◽  
Dependent Manner ◽  
Apoptosis Pathway ◽  
Anticancer Properties ◽  
Multiple Signal ◽  
Underlying Mechanisms ◽  
Induced Apoptosis

Background: Crocetin is a carotenoid extracted from the traditional Chinese medical herb saffron. Previous studies have demonstrated that crocetin possesses anticancer properties that are effective against various cancers. As an extension of our earlier study, the present study explored the underlying mechanisms in crocetin’s anticancer effect on KYSE-150 cells. The phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT), Mitogen-activated protein kinases (MAPK), and p53/p21 signal pathways play an important role in carcinogenesis, progression, and metastasis of carcinoma cells. Thus, we investigated crocetin’s effects on the PI3K/AKT, MAPK, and p53/p21 pathways in esophageal squamous carcinoma cell line KYSE-150 cells. Methods: KYSE-150 cells were treated with various concentrations of crocetin. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltertrazolium bromide assay, Annexin V/PI stain as well as Rh123 stain were used to evaluate the cell viability, apoptosis, and MMP. Western blot was used to detect the expression of PI3K, AKT, ERK1/2, p38, c-Jun NH-terminal kinase (JNK), P53, P21, Bcl-2, Bax, and cleaved caspase-3, which were associated with cell proliferation and apoptosis. Results: Our results showed that crocetin significantly inhibited the proliferation of KYSE-150 cells in a dose- and time-dependent manner. Crocetin also markedly induced cell apoptosis. Furthermore, we have found that crocetin not only inhibited the activation of PI3K/AKT, extracellular signal–regulated kinase-1/2 (ERK1/2), and p38 but also upregulated the p53/p21 level. These regulations ultimately triggered the mitochondrial-mediated apoptosis pathway with an eventual disruption of MMP, increased levels of Bax and cleaved caspase-3, and decreased levels of Bcl-2. Conclusions: These findings suggested that crocetin interfered with multiple signal pathways in KYSE-150 cells. Therefore, this study suggested that crocetin could potentially be used as a therapeutic candidate for the treatment of esophageal cancer.

Involvement of the sphingolipid ceramide in heat-shock-induced apoptosis of bovine oocytes

2011 ◽  
Vol 23 (7) ◽  
pp. 876 ◽  
Author(s):  
Dorit Kalo ◽  
Zvi Roth
Keyword(s):  
Heat Shock ◽  
De Novo ◽  
Specific Inhibitor ◽  
Annexin V ◽  
Developmental Competence ◽  
Control Group ◽  
Cleavage Rate ◽  
Oocyte Developmental Competence ◽  
Induced Apoptosis

Programmed cell death via the sphingomyelin pathway has been suggested to underlie heat-shock disturbance of oocyte developmental competence. A series of experiments were performed to characterise the role of the sphingolipid ceramide in heat-shock-induced apoptosis, and to determine whether ceramide formation can be regulated. Bovine cumulus–oocyte complexes (COCs) were aspirated from ovaries collected in the cold season (November–April), in vitro-matured, fertilised and cultured for 8 days. Exposure of COCs to heat shock (41°C) during maturation reduced cleavage rate and blastocyst formation relative to the control group (38.5°C). Annexin-V binding (V-FITC assay), which is associated with the early apoptotic event of membrane phosphatidylserine turnover, was higher in oocytes exposed to short-term versus long-term heat shock, suggesting that heat-shock-induced apoptosis involves membrane alterations. Similar to heat exposure, oocyte maturation with C2-ceramide had a dose-dependent deleterious effect on the first cleavages and subsequent embryonic development in association with increased annexin-V binding. Blocking endogenous ceramide generation with fumonisin B1, a specific inhibitor of dihydroceramide synthase (i.e. de novo formation), moderated, to some extent, the effects of heat shock on oocyte developmental competence, suggesting that ceramide plays an important role in heat-shock-induced apoptosis.

scholarly journals Autophagy Protects Advanced Glycation End Product-Induced Apoptosis and Expression of MMP-3 and MMP-13 in Rat Chondrocytes

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Wenzhou Huang ◽  
Peng Ao ◽  
Jian Li ◽  
Tianlong Wu ◽  
Libiao Xu ◽  
...  
Keyword(s):  
Western Blotting ◽  
Annexin V ◽  
Protective Role ◽  
Autophagic Flux ◽  
Advanced Glycation ◽  
Age Related ◽  
Glycation End Products ◽  
Induced Apoptosis ◽  
Related Proteins

Aging is one of the most prominent risk factors for the pathological progression of osteoarthritis (OA). One feature of age-related changes in OA is advanced glycation end products (AGEs) accumulation in articular cartilage. Autophagy plays a cellular housekeeping role by removing dysfunctional cellular organelles and proteins. However, the relationship between autophagy and AGE-associated OA is unknown. The aim of this study is to determine whether autophagy participates in the pathology of AGE-treated chondrocytes and to investigate the exact role of autophagy in AGE-induced cell apoptosis and expression of matrix metalloproteinase- (MMP-) 3 and MMP-13. AGEs induced notable apoptosis that was detected by Annexin V/PI double-staining, and the upregulation of MMP-3 and MMP-13 was confirmed by Western blotting. Autophagy-related proteins were also determined by Western blotting, and chondrocytes were transfected with mCherry-GFP-LC3B-adenovirus to monitor autophagic flux. As a result, autophagy significantly increased in chondrocytes and peaked at 6 h. Furthermore, rapamycin (RA) attenuated AGE-induced apoptosis and expression of MMP-3 and MMP-13 by autophagy activation. In contrast, pretreatment with autophagy inhibitor 3-methyladenine (3-MA) enhanced the abovementioned effects of AGEs. We therefore demonstrated that autophagy is linked with AGE-related pathology in rat chondrocytes and plays a protective role in AGE-induced apoptosis and expression of MMP-3 and MMP-13.

Apoptosis induced by lipid-associated membrane proteins fromMycoplasma penetransis mediated by nuclear factor κB activation in mouse macrophage

2008 ◽  
Vol 54 (2) ◽  
pp. 150-158 ◽  
Author(s):  
Yanhua Zeng ◽  
Yimou Wu ◽  
Zhongliang Deng ◽  
Xiaoxing You ◽  
Cuiming Zhu ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Molecular Mechanisms ◽  
Specific Inhibitor ◽  
Annexin V ◽  
Fluorescein Isothiocyanate ◽  
Nuclear Factor Κb ◽  
Pyrrolidine Dithiocarbamate ◽  
Pathogenic Potential ◽  
Mouse Macrophages ◽  
Induced Apoptosis

Mycoplasma penetrans was shown to be involved in alteration of several eukaryotical cells functions and a causative agent in urogenital infectious diseases. Lipid-associated membrane proteins (LAMPs) may be responsible for the pathogenicity of some mycoplamas. In this study, we investigated whether M. penetrans LAMPs have pathogenic potential by inducing apoptosis in mouse macrophages. As analyzed by annexin-V – fluorescein isothiocyanate staining, significant early- and late-stage apoptosis was induced in M. penetrans LAMPs-challenged mouse macrophages. And agarose gel electrophoresis of the DNA of M. penetrans LAMPs-challenged cells revealed a ladder-like pattern of migration of DNA indicative of apoptosis. The possible molecular mechanisms responsible for the induction of apoptosis were also investigated by characterizing the activation of nuclear transcription factor κB (NFκB). NFκB was activated and translocated into the nucleus in mouse macrophages stimulated by M. penetrans LAMPs. The activation of NFκB and M. penetrans LAMPs-induced apoptosis in mouse macrophages was partially inhibited by the NFκB-specific inhibitor pyrrolidine dithiocarbamate. Thus, this study demonstrates that M. penetrans LAMPs may be an important etiological factor owing to their ability to induce apoptosis in mouse macrophages, which is probably mediated through the activation of NFκB.

scholarly journals PTPN11D61Y/+; Vavcre+ Animals Commonly Succumb to Leukemia Relapse Despite Robust Engraftment of Transplanted Wild-Type Hematopoietic Stem and Progenitor Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 496-496
Author(s):  
Stefan P. Tarnawsky ◽  
Mervin C. Yoder ◽  
Rebecca J. Chan
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Wild Type ◽  
Hematopoietic Stem ◽  
Donor Cells ◽  
Stem And Progenitor Cells ◽  
Leukemia Relapse ◽  
Conditioning Regimens

Juvenile Myelomonocytic Leukemia (JMML) is a rare childhood myelodysplastic / myeloproliferative overlap disorder. JMML exhibits myeloid populations with mutations in Ras-Erk signaling genes, most commonly PTPN11, which confer growth hypersensitivity to GM-CSF. While allogeneic hematopoietic stem cell transplant (HSCT) is the treatment of choice for children with JMML, 50% of children succumb to leukemia relapse; however, the mechanism leading to this high relapse rate is unknown. We hypothesized that the hyperinflammatory nature of JMML may damage the bone marrow microenvironment, leading to poor engraftment of normal donor cells following transplant, permitting residual leukemia cells to outcompete the normal graft, and thus promoting leukemia relapse. Using Vav1 promoter-directed Cre, we generated a mouse model of JMML that conditionally expresses gain-of-function PTPN11D61Yin utero during development. While PTPN11D61Y/+; VavCre+embryos did not demonstrate in utero lethality, we observed a modest reduction of PTPN11D61Y/+; VavCre+ mice at the time of weaning compared to predicted Mendelian frequencies. Further, surviving PTPN11D61Y/+; VavCre+ mice developed elevated peripheral blood leukocytosis and monocytosis as early as 4 weeks of age compared to PTPN11+/+; VavCre+ controls. To address the hypothesis that an aberrant bone marrow microenvironment in the PTPN11D61Y/+ mice leads to poor engraftment of wild-type donor cells following transplant, we examined engraftment of wild-type hematopoietic stem and progenitor cells (HSPCs) in the PTPN11D61Y/+; VavCre+ mice and monitored animals for disease relapse. 16-24 week-old diseased PTPN11D61Y/+; VavCre+ and control PTPN11+/+; VavCre+ mice were lethally irradiated (11 Gy split dose) and transplanted with 5 x 105 CD45.1+ wild-type bone marrow low density mononuclear cells (LDMNCs), which simulates a limiting stem cell dose commonly available in a human HSCT setting. 6 weeks post-HSCT, PTPN11D61Y/+; VavCre+recipients demonstrated an unexpected elevated CD45.1+ donor cell contribution in peripheral blood compared to the control PTPN11+/+; VavCre+ recipients. However, despite superior engraftment in the PTPN11D61Y/+; VavCre+ recipients, these mice had a significantly shorter median survival post-HSCT due to a resurgence of recipient CD45.2-derived leukemic cells. We repeated the experiment using a high dose of CD45.1+ LDMNCs (10 x 106 cells) to determine if providing a saturating dose wild-type cells could prevent the relapse of recipient-derived leukemogenesis and normalize the survival of the PTPN11D61Y/+; VavCre+recipients. While this saturating dose of wild-type cells resulted in high peripheral blood chimerism in both the PTPN11D61Y/+; VavCre+ and PTPN11+/+; VavCre+ recipients, the PTPN11D61Y/+; VavCre+ animals nevertheless demonstrated significantly reduced overall survival. When we examined the cause of mortality in the HSCT-treated PTPN11D61Y/+; VavCre+mice, we found enlarged spleens, hypercellular bone marrow, and enlarged thymuses. Flow cytometry revealed that the majority of cells in the peripheral blood, bone marrow, and spleen were recipient-derived CD45.2+ CD4+ CD8+ T cells. To verify that the disease was neoplastic in origin, secondary transplants into CD45.1/.2 recipients were performed from two independent primary PTPN11D61Y/+; VavCre+and two independent primary PTPN11+/+; VavCre+ controls. Secondary recipients of bone marrow from PTPN11D61Y/+; VavCre+ animals rapidly succumbed to a CD45.2-derived T-cell acute lymphoid leukemia (T-ALL). Previous studies demonstrated that wild-type PTPN11 is needed to protect the integrity of the genome by regulating Polo-like kinase 1 (Plk1) during the mitosis of the cell cycle (Liu et al., PNAS, 2016). We now demonstrate that even when PTPN11 mutant animals are provided with saturating doses of wild-type HSCs, dysregulated residual recipient cells are able to produce relapsed disease. Collectively, these studies highlight the propensity of residual mutant PTPN11 cells to transform after being subjected to mutagenic agents that are commonly used for conditioning regimens prior to allogeneic HSCT. These findings suggest that modified pre-HSCT conditioning regimens bearing reduced mutagenicity while maintaining adequate cytoreductive efficacy may yield lower post-HSCT leukemia relapse in children with PTPN11mutations. Disclosures No relevant conflicts of interest to declare.

Motexafin Gadolinium Induces Apoptosis in Lymphoid Cell Lines and Demonstrates Enhanced Biological Activity with Akt Kinase Inhibitors.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3406-3406
Author(s):  
Louie Naumovski ◽  
Jason Ramos ◽  
Jun Chen ◽  
Mint Sirisawad ◽  
David Lucas ◽  
...  
Keyword(s):  
Cell Death ◽  
Chronic Lymphocytic Leukemia ◽  
Cell Lines ◽  
Specific Inhibitor ◽  
Annexin V ◽  
Lymphocytic Leukemia ◽  
Jurkat Cells ◽  
Motexafin Gadolinium ◽  
Akt Phosphorylation ◽  
Induced Apoptosis

Abstract Motexafin gadolinium (MGd, Xcytrin®) is a tumor-selective redox mediator that catalytically oxidizes intracellular reducing metabolites and produces reactive oxygen species (ROS). In this report, we demonstrate that MGd induces apoptosis or growth inhibition in several hematopoietic tumor-derived cell lines and tumor cells from patients with chronic lymphocytic leukemia. Lymphoma (HF-1, Ramos, DHL-4, DB, Hut78 and Raji) and leukemia (Jurkat, HL-60) cell lines were cultured in RPMI 1640 media with 10% heat inactivated fetal bovine serum with or without 50 uM MGd. MGd inhibited the growth of 6 of the cell lines (HF-1, Ramos, HL-60, DHL-4, Jurkat and DB) and was cytotoxic to HF-1. ROS were implicated in MGd-induced cell death since their presence was detected by dichlorofluorescein diacetate staining and peroxiredoxin oxidation in MGd treated HF-1 cells that undergo apoptosis, but not in Jurkat cells that do not undergo MGd-induced apoptosis. MGd triggered an apoptotic pathway in HF-1 cells as demonstrated by loss of mitochondrial membrane potential, release of cytochrome c from mitochondria, activation of caspases, cleavage of PARP and annexin-V binding. MGd also induced cell death and activated caspases in vitro in primary chronic lymphocytic leukemia cells. Protein lysates from cultured cell lines (HF-1, Ramos) were subjected to immunoblot analysis to determine caspase cleavage patterns, and the phosphorylation status of Akt, a kinase that regulates survival pathways. In MGd treated HF-1, phospho-Akt protein levels initially increased 2–3 fold between 30 min and 1 hr (n=4) and then decreased to 40–50% of control levels by 24–48 hrs (n=4). The drop in phospho-Akt protein coincided with an increase in apoptotic cell death as indicated by morphology, staining with Annexin-V and activation of caspases. Addition of a specific inhibitor of Akt phosphorylation (SH-5) reduced Akt phosphorylation in MGd treated HF-1 cells by 90% and enhanced the cytotoxic effect of MGd. In Ramos cells, which do not undergo apoptosis when treated with MGd, co-treatment with MGd and SH-5 decreased phospho Akt levels by only 15% and did not result in cytotoxicity. These data point to a potential role for Akt in MGd-induced apoptosis and suggest that MGd activity may be enhanced by inhibition of Akt. These data show that the pro-apoptotic effects of MGd involve caspase activation and provide a rationale to evaluate MGd in the treatment of lymphoma and leukemia patients.

Melatonin inhibits high glucose-induced ox-LDL/LDL expression and apoptosis in human umbilical endothelial cells

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yee Lian Tiong ◽  
Khuen Yen Ng ◽  
Rhun Yian Koh ◽  
Gnanajothy Ponnudurai ◽  
Soi Moi Chye
Keyword(s):  
Endothelial Cells ◽  
Umbilical Vein ◽  
Annexin V ◽  
Diabetic Patients ◽  
Therapeutic Effects ◽  
Pathway Activation ◽  
Increased Risk ◽  
Underlying Mechanisms ◽  
Induced Apoptosis ◽  
Umbilical Vein Endothelial Cells

AbstractBackgroundCardiovascular disease (CVD) is one of the major cause of mortality in diabetic patients. Evidence suggests that hyperglycemia in diabetic patients contributes to increased risk of CVD. This study is to investigate the therapeutic effects of melatonin on glucose-treated human umbilical vein endothelial cells (HUVEC) and provide insights on the underlying mechanisms.Materials and methodsCell viability was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Reactive oxygen species (ROS) and membrane potential was detected using 2′,7′-dichlorofluorescein diacetate and 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethylbenzimidazolcarbocyanine iodide (JC-1) dye staining, respectively. While, cell apoptosis was determined by Annexin-V staining and protein expression was measured using Western blot.ResultsOur results suggested that melatonin inhibited glucose-induced ROS elevation, mitochondria dysfunction and apoptosis on HUVEC. Melatonin inhibited glucose-induced HUVEC apoptosis via PI3K/Akt signaling pathway. Activation of Akt further activated BcL-2 pathway through upregulation of Mcl-1 expression and downregulation Bax expression in order to inhibit glucose-induced HUVEC apoptosis. Besides that, melatonin promoted downregulation of oxLDL/LOX-1 in order to inhibit glucose-induced HUVEC apoptosis.ConclusionsIn conclusion, our results suggested that melatonin exerted vasculoprotective effects against glucose-induced apoptosis in HUVEC through PI3K/Akt, Bcl-2 and oxLDL/LOX-1 signaling pathways.

scholarly journals Trichosanthis Pericarpium Aqueous Extract Protects H9c2 Cardiomyocytes from Hypoxia/Reoxygenation Injury by Regulating PI3K/Akt/NO Pathway

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2409 ◽  
Author(s):  
Donghai Chu ◽  
Zhenqiu Zhang
Keyword(s):  
Cell Viability ◽  
Aqueous Extract ◽  
Specific Inhibitor ◽  
Annexin V ◽  
No Production ◽  
H9c2 Cardiomyocytes ◽  
Mrna And Protein Expression ◽  
Underlying Mechanisms ◽  
Apoptotic Effects ◽  
Hypoxia Reoxygenation

Trichosanthis Pericarpium (TP) is a traditional Chinese medicine for treating cardiovascular diseases. In this study, we investigated the effects of TP aqueous extract (TPAE) on hypoxia/reoxygenation (H/R) induced injury in H9c2 cardiomyocytes and explored the underlying mechanisms. H9c2 cells were cultured under the hypoxia condition induced by sodium hydrosulfite for 30 min and reoxygenated for 4 h. Cell viability was measured by MTT assay. The amounts of LDH, NO, eNOS, and iNOS were tested by ELISA kits. Apoptotic rate was detected by Annexin V-FITC/PI staining. QRT-PCR was performed to analyze the relative mRNA expression of Akt, Bcl-2, Bax, eNOS, and iNOS. Western blotting was used to detect the expression of key members in the PI3K/Akt pathway. Results showed that the pretreatment of TPAE remarkably enhanced cell viability and decreased apoptosis induced by H/R. Moreover, TPAE decreased the release of LDH and expression of iNOS. In addition, TPAE increased NO production and Bcl-2/Bax ratio. Furthermore, the mRNA and protein expression of p-Akt and eNOS were activated by TPAE pretreatment. On the contrary, a specific inhibitor of PI3K, LY294002 not only inhibited TPAE-induced p-Akt/eNOS upregulation but alleviated its anti-apoptotic effects. In conclusion, results indicated that TPAE protected against H/R injury in cardiomyocytes, which consequently activated the PI3K/Akt/NO signaling pathway.

248 INVOLVEMENT OF THE SPHINGOLIPID, CERAMIDE, IN HEAT SHOCK-INDUCED APOPTOSIS IN BOVINE OOCYTE

2009 ◽  
Vol 21 (1) ◽  
pp. 222 ◽  
Author(s):  
D. Kalo ◽  
Z. Roth
Keyword(s):  
Heat Shock ◽  
Specific Inhibitor ◽  
Annexin V ◽  
Developmental Competence ◽  
Immunofluorescent Staining ◽  
Blastocyst Formation ◽  
Short Term ◽  
Oocyte Developmental Competence ◽  
Induced Apoptosis

Programmed cell death through the sphingomyelin pathway has been suggested to underlie the mechanism by which heat shock disturbs oocyte developmental competence. Serial experiments were performed to characterize the role of the sphingolipid ceramide in heat-shock-induced apoptosis, and to determine whether ceramide formation could be regulated. In all experiments, bovine cumulus–oocyte complexes (COC) were aspirated from ovaries collected at the abattoir. Cumulus–oocyte complexes were matured (22 h, 38.5°C, 5% CO2), in vitro fertilized (18 h, 38.5°C, 5% CO2), and cultured for 8 days (KSOM; 38.5°C, 5% CO2, 5% O2). In the first experiment, COC were matured at 38.5°C (n = 673) or 41°C (heat shock; n = 718). Exposure of COC to heat shock during maturation reduced cleavage (92.3 v. 84.2%; P < 0.05) and blastocyst formation rates (24.1 v. 14.6%; P < 0.05) relative to the control groups. In the second experiment, COC (n = 563) were exposed to either long-term (22 h) or short-term (0.5 to 3.5 h) heat shock during maturation. An Annexin V-FITC assay (Bender) was used to identify the turnover of phosphatidylserine, one of the features of early-stage apoptosis. In addition, a subgroup of matured oocytes (n = 384) were denuded and fixed in 2% paraformaldehyde, followed by immunofluorescent staining using anti-ceramide (Alexis) to detect ceramide levels and counterstaining with Hoechst (Sigma). Immunofluorescent staining showed no difference in endogenous ceramide levels between groups. Similarly, annexin expression did not differ between groups at the end of the maturation but was higher (P < 0.05) in oocytes exposed to short-term heat shock than in those subjected to long-term heat shock, suggesting that early features of apoptosis should be examined at a specific time of heat exposure. Another experiment was performed to examine the effect of ceramide on oocyte developmental competence. Cumulus–oocyte complexes (n = 1185) were matured with or without 10, 30, and 50 μm C2-ceramide (Sigma). An Annexin V-FITC assay was used with a subgroup of oocytes (n = 137) that were matured with or without 50 μm C2-ceramide for 2 h. To examine the major pathway of ceramide generation, heat-shocked COC were matured with or without 5 μm fumonisin B1 (FB1; Sigma), a specific inhibitor of dihydroceramide synthase (i.e. de novo formation) and ceramide synthase (i.e. salvage pathway), or with 5 μm desipramine hydrochloride (DH; Sigma), a specific inhibitor of the acid sphingomyelinase (i.e. hydrolysis). Results revealed that maturation in 50 μm C2-ceramide increased (P < 0.05) annexin expression in association with reducing cleavage rate and blastocyst formation (P < 0.05). Although not significant, maturation with FB1 moderated the heat-shock effect on oocyte developmental competence. Similarly, 5 μm DH increased the blastocyst formation rate for heat-shocked oocytes from a level of 17% to the control level (22.5%). In summary, ceramide appears to play an important role in heat-shock-induced apoptosis because blocking ceramide formation alleviated its deleterious effect. Research was supported in part by USDA Grant 2007-35203 and BARD Grant 3986-07

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