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Cell Apoptosis (cell + apoptosi)
Kinds of Cell Apoptosis Selected AbstractsEffects of interleukin 18 on injury and activation of human proximal tubular epithelial cellsNEPHROLOGY, Issue 1 2007DONG LIANG SUMMARY: Background/Aims: Injury and activation of tubular proximal epithelial cells (TEC) play central roles in renal tubulointerstitial fibrosis (TIF), but its mechanisms remain obscure. Interleukin 18 (IL-18) is overproduced during chronic kidney diseases (CKD), but how IL-18 affects the biological behaviour of TEC is not clear. The aim of the present study is to reveal the role of IL-18 in renal TIF. Methods: The expressions of IL-18 and IL-18 receptor in TEC were detected by immunohistochemical staining in vivo and by reverse transcriptase polymerase chain reaction (RT-PCR) in vitro. TEC line (HK-2 cells) were incubated without or with IL-18. Cell proliferation and cell cycle were evaluated by methyl thiazolyl tetrazolium assay and flow cytometric analysis, respectively. Cell apoptosis was assessed by Hoechst 33258 staining. Expression of ,-smooth muscle actin was evaluated by RT-PCR, immunocytochemical staining and flow cytometric analysis, respectively. Type I collagen, fibronectin, MCP-1 and RANTES in cultured supernatants were measured by enzyme-linked immunosorbent assay. Results: IL-18 expression in TEC increased significantly in CKD state. IL-18 receptor was constitutively expressed in normal proximal TEC, and its expression increased strongly in CKD state. Proliferation and cell cycle of HK-2 cells were not affected by IL-18. Cell apoptosis, ,-smooth muscle actin expression, type I collagen and fibronectin production as well as MCP-1 secretion were promoted by IL-18 in dosage- and/or time-dependent manners, but RANTES secretion was not affected. Conclusion: IL-18 may play a crucial role in the process of TIF by promoting TEC injury and activation, and could be a target of the therapeutic approaches against TIF. [source] Carbocisteine inhibits oxidant-induced apoptosis in cultured human airway epithelial cellsRESPIROLOGY, Issue 7 2009Motoki YOSHIDA ABSTRACT Background and objective: Increased oxidant levels have been associated with exacerbations of COPD, and L-carbocisteine, a mucolytic agent, reduces the frequency of exacerbations. The mechanisms underlying the inhibitory effects of L-carbocisteine on oxidant-induced COPD exacerbations were examined in an in vitro study of human airway epithelial cells. Methods: In order to examine the antioxidant effects of L-carbocisteine, human tracheal epithelial cells were treated with L-carbocisteine and exposed to hydrogen peroxide (H2O2). Cell apoptosis was assessed using a cell death detection ELISA, and the pathways leading to cell apoptosis were examined by measurement of caspase-3 and caspase-9 by western blot analysis with fluorescent detection. Results: The proportion of apoptotic cells in human tracheal epithelium was increased in a concentration- and time-dependent manner, following exposure to H2O2. Treatment with L-carbocisteine reduced the proportion of apoptotic cells. In contrast, H2O2 did not increase the concentration of LDH in supernatants of epithelial cells. Exposure to H2O2 activated caspase-3 and caspase-9, and L-carbocisteine inhibited the H2O2 -induced activation of these caspases. L-carbocisteine activated Akt phosphorylation, which modulates caspase activation, and the inhibitors of Akt, LY294002 and wortmannin, significantly reversed the inhibitory effects of L-carbocisteine on H2O2 -induced cell apoptosis. Conclusions: These findings suggest that in human airway epithelium, L-carbocisteine may inhibit cell damage induced by H2O2 through the activation of Akt phosphorylation. L-carbocisteine may have antioxidant effects, as well as mucolytic activity, in inflamed airways. [source] Cationic Ester Porphyrins Cause High Levels of Phototoxicity in Tumor Cells and Induction of Apoptosis in HeLa CellsCHEMISTRY & BIODIVERSITY, Issue 7 2009Lin Wu Abstract A series of cationic ester porphyrins are much more cytotoxic to tumor cells than photofrin, meso -tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP4), and cisplatin. The lowest IC50 value for SGC7901 is ca. 6,nMin vitro with irradiation. These porphyrins also exhibited the most potent photo-induced cytotoxicity without photobleaching. HeLa Cell apoptosis induced by cationic ester porphyrins after illumination was examined by flow cytometric analysis, staining assays with propidium iodide and annexin V FITC-PI, and further confirmed by observing morphological changes in the cells. The result of this study indicates that these cationic ester porphyrins may be applied in photodynamic therapy (PDT) in the future. [source] Effect of storage media on human periodontal ligament cell apoptosisDENTAL TRAUMATOLOGY, Issue 1 2008Mónica M. Chamorro However, the mechanisms by which different storage conditions alter the functional status of PDL cells have not been determined. The purpose of the present study was to investigate, in vitro, the level of programed cell death or apoptosis in a population of PDL cells following storage under different conditions. Primary human PDL cells were plated into 24-well-culture plates and allowed to attach for 24 h. Cells were then exposed for 1 h to milk, Hank's balanced salt solution (HBSS), Soft Wear contact lens solution or Gatorade at room temperature or on ice. Culture medium was used as a negative control. Apoptosis was evaluated at 24, 48, and 72 h after treatment on quadruplicate samples by using the ST 160 ApopTag Fluorescein Direct In Situ Detection Kit. The total number of cells and the total number of apoptotic cells were counted. The results indicated that at 24 and 72 h, PDL treated with Gatorade and the contact lens solution displayed the highest percentages of apoptotic cells when compared with the other treatment groups at room temperature. Overall, cells treated on ice showed significantly lower levels of apoptosis when compared with treatments at room temperature. In conclusion, the results indicated that apoptosis plays a major role in cell death in cells treated with Gatorade and contact lens solutions in comparison to other storage solutions and that storage on ice can inhibit programed cell death. [source] A link between endoplasmic reticulum stress-induced , -cell apoptosis and the group VIA Ca2+ -independent phospholipase A2 (iPLA2,)DIABETES OBESITY & METABOLISM, Issue 2010X. Lei Endoplasmic reticulum (ER) stress is becoming recognized as an important contributing factor in various diseases, including diabetes mellitus. Prolonged ER stress can cause , -cell apoptosis; however, the underlying mechanism(s) that contribute to this process are not well understood. Early reports suggested that arachidonic acid metabolites and a Ca2+ -independent phospholipase A2 (iPLA2) activity play a role in , -cell apoptosis. The PLA2 family of enzymes catalyse the hydrolysis of the sn -2 substituent (i.e. arachidonic acid) of membrane phospholipids. In light of our findings that the pancreatic islet , -cells are enriched in arachidonate-containing phospholipids and express the group VIA iPLA2,, we considered the possibility that iPLA2, participates in ER stress-induced , -cell apoptosis. Our work revealed a novel mechanism, involving ceramide generation and triggering of mitochondrial abnormalities, by which iPLA2, participates in the , -cell apoptosis process. Here, we review our evidence linking ER stress, , -cell apoptosis and iPLA2,. Continued studies in this area will increase our understanding of the contribution of iPLA2, to the evolution of diabetes mellitus and will further our knowledge of factors that influence , -cell health in diabetes mellitus and identify potential targets for future therapeutic interventions to prevent , -cell death. [source] Exendin-4 protects pancreatic beta cells from human islet amyloid polypeptide-induced cell damage: potential involvement of AKT and mitochondria biogenesisDIABETES OBESITY & METABOLISM, Issue 9 2010R. Fan Aim: Glucagon-like peptide-1 (GLP-1) stimulates beta-cell proliferation and enhances beta-cell survival, whereas oligomerization of human islet amyloid polypeptide (hIAPP) may induce beta-cell apoptosis and reduce beta-cell mass. Type 2 diabetes is associated with increased expression of IAPP. As GLP-1-based therapy is currently developed as a novel antidiabetic therapy, we examined the potential protective action of the GLP-1 receptor agonist exendin-4 on hIAPP-induced beta-cell apoptosis. Methods: The study was performed in clonal insulinoma (INS-1E) cells. Both method of transcriptional and translational and sulphorhodamine B (SRB) assays were used to evaluate cell viability and cell mass. Western blot analysis was applied to detect protein expression. Transfection of constitutively active protein kinase B (PKB/AKT) was performed to examine the role of AKT. Mitochondrial biogenesis was quantified by mitogreen staining and RT-PCR. Results: First, we confirmed that hIAPP induced cell apoptosis and growth inhibition in INS-1E cells. These effects were partially protected by exendin-4 in association with partial recovery of the hIAPP-mediated AKT inhibition. Furthermore, AKT constitutive activation attenuated hIAPP-induced apoptosis, whereas PI3K/AKT inhibition abrogated exendin-4-mediated effects. These findings suggest that the antiapoptotic and proliferative effects of exendin-4 in hIAPP-treated INS-1E cells were partially mediated through AKT pathway. Moreover, hIAPP induced FOXO1 but inhibited pdx-1 nucleus translocation. These effects were restored by exendin-4. Finally, mitogreen staining and RT-PCR revealed enhanced mitochondrial biogenesis by exendin-4 treatment. Conclusions: Collectively, these results suggest that GLP-1 receptor agonist protects beta cells from hIAPP-induced cell death partially through the activation of AKT pathway and improved mitochondrial function. [source] Balancing needs and means: the dilemma of the ,-cell in the modern worldDIABETES OBESITY & METABOLISM, Issue 2009G. Leibowitz The insulin resistance of type 2 diabetes mellitus (T2DM), although important for its pathophysiology, is not sufficient to establish the disease unless major deficiency of ,-cell function coexists. This is demonstrated by the fact that near-physiological administration of insulin (CSII) achieved excellent blood glucose control with doses similar to those used in insulin-deficient type 1 diabetics. The normal ,-cell adapts well to the demands of insulin resistance. Also in hyperglycaemic states some degree of adaptation does exist and helps limit the severity of disease. We demonstrate here that the mammalian target of rapamycin (mTOR) system might play an important role in this adaptation, because blocking mTORC1 (complex 1) by rapamycin in the nutritional diabetes model Psammomys obesus caused severe impairment of ,-cell function, increased ,-cell apoptosis and progression of diabetes. On the other hand, under exposure to high glucose and FFA (gluco-lipotoxicity), blocking mTORC1 in vitro reduced endoplasmic reticulum (ER) stress and ,-cell death. Thus, according to the conditions of stress, mTOR may have beneficial or deleterious effects on the ,-cell. ,-Cell function in man can be reduced without T2DM/impaired glucose tolerance (IGT). Prospective studies have shown subjects with reduced insulin response to present, several decades later, an increased incidence of IGT/T2DM. From these and other studies we conclude that T2DM develops on the grounds of ,-cells whose adaptation capacity to increased nutrient intake and/or insulin resistance is in the lower end of the normal variation. Inborn and acquired factors that limit ,-cell function are diabetogenic only in a nutritional/metabolic environment that requires high functional capabilities from the ,-cell. [source] GLP-1: physiological effects and potential therapeutic applicationsDIABETES OBESITY & METABOLISM, Issue 11 2008Kasper Aaboe Glucagon-like peptide 1 (GLP-1) is a gut-derived incretin hormone with the potential to change diabetes. The physiological effects of GLP-1 are multiple, and many seem to ameliorate the different conditions defining the diverse physiopathology seen in type 2 diabetes. In animal studies, GLP-1 stimulates ,-cell proliferation and neogenesis and inhibits ,-cell apoptosis. In humans, GLP-1 stimulates insulin secretion and inhibits glucagon and gastrointestinal secretions and motility. It enhances satiety and reduces food intake and has beneficial effects on cardiovascular function and endothelial dysfunction. Enhancing incretin action for therapeutic use includes GLP-1 receptor agonists resistant to degradation (incretin mimetics) and dipeptidyl peptidase (DPP)-4 inhibitors. In clinical trials with type 2 diabetic patients on various oral antidiabetic regimes, both treatment modalities efficaciously improve glycaemic control and ,-cell function. Whereas the incretin mimetics induce weight loss, the DPP-4 inhibitors are considered weight neutral. In type 1 diabetes, treatment with GLP-1 shows promising effects. However, several areas need clinical confirmation: the durability of the weight loss, the ability to preserve functional ,-cell mass and the applicability in other than type 2 diabetes. As such, long-term studies and studies with cardiovascular end-points are needed to confirm the true benefits of these new classes of antidiabetic drugs in the treatment of diabetes mellitus. [source] Insulitis in type 2 diabetesDIABETES OBESITY & METABOLISM, Issue 2008M. Böni-Schnetzler Islets of patients with type 2 diabetes have the feature of an inflammatory process reflected by the presence of cytokines, immune cells, ,-cell apoptosis, amyloid deposits and fibrosis. Indeed, ,-cells from patients with type 2 diabetes display inflammatory markers, including increased interleukin (IL)-1, expression. Furthermore, increased islet-associated macrophages are observed in human type 2 diabetic patients and in most animal models of diabetes. Importantly, increased numbers of macrophages are detectable very early in high fat,fed mice islets, before the onset of diabetes. These immune cells are most likely attracted by islet-derived chemokines, produced in response to metabolic stress, and under the control of IL-1,. It follows that modulation of intra-islet inflammatory mediators, in particular IL-1,, may prevent insulitis in type 2 diabetes and therefore presents itself as a possible causal therapy with disease-modifying potential. [source] Effects of dietary fatty acids on insulin sensitivity and secretionDIABETES OBESITY & METABOLISM, Issue 6 2004Melania Manco Globalization and global market have contributed to increased consumption of high-fat, energy-dense diets, particularly rich in saturated fatty acids( SFAs). Polyunsaturated fatty acids (PUFAs) regulate fuel partitioning within the cells by inducing their own oxidation through the reduction of lipogenic gene expression and the enhancement of the expression of those genes controlling lipid oxidation and thermogenesis. Moreover, PUFAs prevent insulin resistance by increasing membrane fluidity and GLUT4 transport. In contrast, SFAs are stored in non-adipocyte cells as triglycerides (TG) leading to cellular damage as a sequence of their lipotoxicity. Triglyceride accumulation in skeletal muscle cells (IMTG) derives from increased FA uptake coupled with deficient FA oxidation. High levels of circulating FAs enhance the expression of FA translocase the FA transport proteins within the myocites. The biochemical mechanisms responsible for lower fatty acid oxidation involve reduced carnitine palmitoyl transferase (CPT) activity, as a likely consequence of increased intracellular concentrations of malonyl-CoA; reduced glycogen synthase activity; and impairment of insulin signalling and glucose transport. The depletion of IMTG depots is strictly associated with an improvement of insulin sensitivity, via a reduced acetyl-CoA carboxylase (ACC) mRNA expression and an increased GLUT4 expression and pyruvate dehydrogenase (PDH) activity. In pancreatic islets, TG accumulation causes impairment of insulin secretion. In rat models, ,-cell dysfunction is related to increased triacylglycerol content in islets, increased production of nitric oxide, ceramide synthesis and ,-cell apoptosis. The decreased insulin gene promoter activity and binding of the pancreas-duodenum homeobox-1 (PDX-1) transcription factor to the insulin gene seem to mediate TG effect in islets. In humans, acute and prolonged effects of FAs on glucose-stimulated insulin secretion have been widely investigated as well as the effect of high-fat diets on insulin sensitivity and secretion and on the development of type 2 diabetes. [source] Advanced glycation end products-induced apoptosis attenuated by PPAR, activation and epigallocatechin gallate through NF-,B pathway in human embryonic kidney cells and human mesangial cellsDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 5 2010Yao-Jen Liang Abstract Background Diabetic nephropathy has attracted many researchers' attention. Because of the emerging evidence about the effects of advanced glycation end products (AGEs) and receptor of AGE (RAGE) on the progression of diabetic nephropathy, a number of different therapies to inhibit AGE or RAGE are under investigation. The purpose of the present study was to examine whether peroxisome proliferator-activated receptor , (PPAR,) agonist (L-165041) or epigallocatechin gallate (EGCG) alters AGE-induced pro-inflammatory gene expression and apoptosis in human embryonic kidney cells (HEK293) and human mesangial cells (HMCs). Methods The HEK cells and HMC were separated into the following groups: 100 µg/mL AGE alone for 18 h; AGE treated with 1 µM L-165041 or 10 µM EGCG, and untreated cells. Inflammatory cytokines, nuclear factor-,B pathway, RAGE expression, superoxide dismutase and cell apoptosis were determined. Results AGE significantly increased tumour necrosis factor-, (TNF-,), a major pro-inflammatory cytokine. The mRNA and protein expression of RAGE were up-regulated. These effects were significantly attenuated by pre-treatment with L-165041 or EGCG. AGE-induced nuclear factor-,B pathway activation and both cells apoptosis were also inhibited by L-165041 or EGCG. Furthermore, both L-165041 and EGCG increased superoxide dismutase levels in AGE-treated HEK cells and HMC. Conclusions This study demonstrated that PPAR, agonist and EGCG decreased the AGE-induced kidney cell inflammation and apoptosis. This study provides important insights into the molecular mechanisms of EGCG and PPAR, agonist in attenuation of kidney cell inflammation and may serve as a therapeutic modality to treat patients with diabetic nephropathy. Copyright © 2010 John Wiley & Sons, Ltd. [source] Fine-needle aspiration biopsy of metastatic malignant melanoma resembling a malignant peripheral nerve sheath tumorDIAGNOSTIC CYTOPATHOLOGY, Issue 10 2008Svetoslav Bardarov M.D. Abstract We report a case of metastatic malignant melanoma resembling a malignant peripheral sheath tumor, which posed a significant diagnostic challenge. The patient is a 76-year-old male, who presented in the emergency room with bilateral chest pain exacerbated by inspiration. The pain was present for 3 week and was not exacerbated by physical exercise. The diagnostic workup revealed bilateral parenchymal pulmonary infiltrates. The CT-scan guided fine-needle aspiration and the core biopsies of the largest pulmonary lesion revealed high-grade spindle cell neoplasm with individual cell apoptosis and necrosis. The immunohistochemical profile on the cell block showed that the cells are positive for Vimentin. The S-100 stain showed only focal positivity. The immunohistochemical stains for HMB45, Melan A, pancytokeratin, and smooth muscle actin were negative. Five years ago the patient was diagnosed with melanoma on the back with Clark level of IV. The melanoma was excised with clear margins and sentinel lymph nodes were negative. Careful examination of patient's previous slides revealed an area of spindle cell melanoma adjacent to a nodular type melanoma. Based on the patient's previous history, current clinico-pathologic presentation and immunohistochemical profile, the diagnosis of metastatic malignant melanoma resembling peripheral nerve sheath tumor was favored over the diagnosis of metastatic malignant spindle cell neoplasm of unknown primary site, which by itself is very rare clinical scenario. Diagn. Cytopathol. 2008;36:754,757. © 2008 Wiley-Liss, Inc. [source] LBY135, a novel anti-DR5 agonistic antibody induces tumor cell,specific cytotoxic activity in human colon tumor cell lines and xenografts,DRUG DEVELOPMENT RESEARCH, Issue 2 2008Jing Li Abstract TRAIL (TNF-related apoptosis-inducing ligand) induces apoptosis on binding to DR4 and DR5 receptors on the surface of tumor cells. These receptors are of particular interest in the development of cancer therapeutics as they preferentially mediate tumor cell apoptosis. We have generated a chimeric anti-DR5 agonistic antibody, LBY135, from its murine parental antibody, LCR211, identified using hybridoma technology. Both LCR211 and LBY135 specifically bind to DR5 with nanomolar affinity, mimic TRAIL to induce cell death in tumor cells, and have little effect on non-transformed cells in vitro. The anti-DR5 antibody reduced viability in 45% of a panel of 40 human colon cancer cell lines with IC50 values of 20,nM or less. In vivo, using human colorectal tumor xenograft mouse models, LCR211 induced tumor regression and showed enhanced efficacy when combined with 5-FU. Both in vitro evaluation of ADCC (antibody-dependent cell-mediated cytotoxicity) and CDC (complement-dependent cytotoxicity), and in vivo studies using a non-functional DR5 specific antibody or SCID-Beige mice, suggested ADCC and CDC are unlikely to be the mechanism to ablate tumors in vivo. LBY135 and LCR211 appear to mediate cell death and tumor regression mainly through apoptosis, as demonstrated by the activation of caspase 3, caspase 8, M30, and TUNEL assay. In addition, the discovery of synergy between cross-linked LBY135 and TRAIL not only revealed the unique epitope of LBY135, but also demonstrated an additional mechanism of action for LBY135 in vivo. LBY135 demonstrates promise as a novel therapeutic for cancer treatment and is currently in Phase I clinical trials. Drug Dev Res 69: 69,82, 2008. © 2008 Wiley-Liss, Inc. [source] TACI attenuates antibody production costimulated by BAFF-R and CD40EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2007Daisuke Sakurai Abstract B cell activating factor of the TNF family (BAFF), plays critical roles in B cell survival, activation, differentiation, and antibody (Ab) production. BAFF binds to three receptors: BAFF-R, transmembrane activator and calcium-modulator and cyclophilin ligand interactor (TACI) and B cell maturation antigen. While BAFF-R is the primary receptor for B cell costimulation by BAFF, TACI is reported to serve as a positive or negative regulator for B cell responses depending on conditions. To determine the real role of TACI in B cell responses, we examined the functional relationship between TACI and BAFF-R in Ab production from human peripheral blood B cells using agonistic mAb. BAFF-R and CD40 enhanced IgG secretion and B cell proliferation, which were inhibited by TACI. Although TACI induced mild B cell apoptosis, its extent did not correlate with that of TACI-mediated inhibition of IgG secretion. In addition, TACI inhibited B-lymphocyte-induced maturation protein-1 expression, IgG secretion from previously IgG-negative selected B cells, and activation-induced cytidine deaminase expression enhanced by BAFF-R and CD40. Importantly, BAFF-R and CD40 enhanced B cell responsiveness to TACI-mediated suppression. Thus, BAFF may attenuate T cell-independent and -dependent B cell responses by TACI. See accompanying commentary http://dx.doi.org/10.1002/eji.200636914 [source] Caspase-dependent and -independent apoptosis of mast cells induced by withdrawal of IL-3 is prevented by Toll-like receptor,4-mediated lipopolysaccharide stimulationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2003Hideshi Yoshikawa Abstract IL-3-dependent mucosal-like mast cells undergo apoptosis upon withdrawal of IL-3. Generally, the apoptosis is mediated by the activation of caspases and inhibited by addition of the pan-caspase inhibitors z-VAD-FMK or BOC-D-FMK. However, DNA fragmentation, a typical characteristic of apoptosis, is not inhibited by z-VAD-FMK or BOC-D-FMK in mast cell apoptosis. In this study, we demonstrate that the apoptosis of mast cells is mediated by both caspase-dependent and -independent mechanisms. The caspase-independent apoptosis is mediated by the translocation of endonuclease,G from mitochondria into nuclei. Withdrawal of IL-3 caused down-regulation of Bcl-xL, resulting in a drop in mitochondrial membrane transition potential followed by the release of cytochrome,c and endonuclease,G from mitochondria. However, stimulation of mast cells through Toll-like receptor,4 (TLR4) by lipopolysaccharide prevented mast cell apoptosis by inducing expression of Bcl-xL. Moreover, the activation of mast cells by LPS is enhanced in the presence of IFN-,, which up-regulates the expression of cell surface TLR4. Taken together, these observations provide evidence that mast cells play importantroles not only in allergic reactions but also in innate immunity recognizing enterobacteria through TLR4, and are regulated differently from allergic inflammation by Th1 cytokines. [source] Phosphorylation of NF-,B proteins by cyclic GMP-dependent kinaseFEBS JOURNAL, Issue 10 2003A noncanonical pathway to NF-, B activation The transcription factor NF-,B is activated in cellular stress responses. This requires rapid regulation of its function, which is accomplished, in part, by various modes of phosphorylation. Even though diverse DNA binding subunits of NF-,B proteins may transactivate from distinct recognition sequences, the differential regulation of transcription from the large number of NF-,B responsive sites in various gene promoters and enhancers has been incompletely understood. The cyclic GMP-dependent kinase (PKG) is an important mediator of signal transduction that may induce gene expression through cAMP response element binding protein (CREB) and through other, yet undefined, mechanisms. We have previously characterized a signal transduction pathway that leads to activation-induced cell death in T-lymphocytes and involves the activation of PKG. Here we demonstrate that the NF-,B proteins p65, p49 (also called p52), and p50 are specific substrates for this kinase. PKG dose-dependently increases the transactivating activity of p65 from the NF-,B consensus sequence. It also mediates dose-dependently an increase in transcriptional activity by p49 or p50 from a unique CCAAT/enhance binding protein (C/EBP)-associated NF-,B site, but not from the consensus site. Phosphorylation of p65, p50, or p49 does not alter their subcellular distribution. Because the release of cytosolic p65/p50 heterodimers into the nucleus is by itself insufficient to differentiate all the numerous NF-,B promoter sequences, phosphorylation of the DNA-binding subunits reveals a form of differential regulation of NF-,B activity and it implies a novel pathway for PKG-induced gene transcription. These observations may bear on mechanisms of programmed cell death in T-lymphocytes. They may also be relevant to ongoing efforts to induce cancer cell apoptosis through activation of PKG. [source] Silencing MAT2A gene by RNA interference inhibited cell growth and induced apoptosis in human hepatoma cellsHEPATOLOGY RESEARCH, Issue 5 2007Quanyan Liu Aims:, A switch in gene expression from MAT1A to MAT2A was found in liver cancer, suggesting that MAT2A plays an important role in facilitating cancer growth. MAT2A is an interesting target for antineoplastic therapy. The molecular mechanisms of silencing MAT2A by RNA interference inhibited cell growth and induced apoptosis in hepatoma cells was studied. Methods:, We investigated the effects of MAT2A on S-adenosyl-methionine (SAM) production, cell growth and apoptotic cell death in hepatoma cell lines (Bel-7402, HepG2, and Hep3B) using an RNA interference approach. Results:, The treatment of three hepatoma cell lines with small interfering RNA (siRNA) targeting to the MAT2A gene resulted in reducing the MAT II activity, facilitating SAM production, increasing SAM : SAH ratio, inhibiting cell growth and inducing cell apoptosis in hepatoma cells. In addition, silencing MAT2A gene resulted in the stimulation of MAT1A mRNA production, which was blocked by 3-deazaadenosine and l -ethionine, but not d -ethionine, suggesting that such effect was specific and mediated by upregulation of SAM level and SAM : S-adenosylethionine (SAH) ratio. Conclusion:, Silencing MAT2A by sequence-specific small interfering RNA caused a switch of MAT gene expression from MAT2A to MAT1A, which led the content of SAM to change to a higher steady-state level that resulted in the inhibition of cell growth and the induction of apoptotic cell death in human hepatoma cells. These results also suggested that MAT2A may hold potential as a new target for liver cancer gene therapy. [source] ,-Arrestin 2 regulates toll-like receptor 4-mediated apoptotic signalling through glycogen synthase kinase-3,IMMUNOLOGY, Issue 4 2010Hui Li Summary Toll-like receptor 4 (TLR4), a key member of the TLR family, has been well characterized by its function in the induction of inflammatory products of innate immunity. However, the involvement of TLR4 in a variety of apoptotic events by an unknown mechanism has been the focus of great interest. Our investigation found that TLR4 promoted apoptotic signalling by affecting the glycogen synthase kinase-3, (GSK-3,) pathway in a serum-deprivation-induced apoptotic paradigm. Serum deprivation induces GSK-3, activation in a pathway that leads to subsequent cell apoptosis. Intriguingly, this apoptotic cascade is amplified in presence of TLR4 but greatly attenuated by ,-arrestin 2, another critical molecule implicated in TLR4-mediated immune responses. Our data suggest that the association of ,-arrestin 2 with GSK-3, contributes to the stabilization of phospho-GSK-3,, an inactive form of GSK-3,. It becomes a critical determinant for the attenuation of TLR4-initiated apoptosis by ,-arrestin 2. Taken together, we demonstrate that the TLR4 possesses the capability of accelerating GSK-3, activation thereby deteriorating serum-deprivation-induced apoptosis; ,-arrestin 2 represents an inhibitory effect on the TLR4-mediated apoptotic cascade, through controlling the homeostasis of activation and inactivation of GSK-3,. [source] Roles of proinflammatory cytokines and the Fas/Fas ligand interaction in the pathogenesis of inflammatory myopathiesIMMUNOLOGY, Issue 1pt2 2009Masahiro Kondo Summary Within the lesions of inflammatory myopathies, muscle fibres and invading mononuclear cells express Fas and Fas ligand (FasL), respectively. However, the roles of the Fas/FasL interaction in the pathogenesis of inflammatory myopathies are not fully understood. In the present study, we investigated the roles of proinflammatory cytokines and the Fas/FasL system in the pathogenesis of inflammatory myopathies. In vitro culturing of muscle cells with the proinflammatory cytokines interferon-,, tumour necrosis factor-,, and interleukin (IL)-1, synergistically increased Fas expression, susceptibility to Fas-mediated apoptosis, and the expression of cytoplasmic caspases 8 and 3. In addition, culturing of muscle cells with activated CD4+ T cells induced muscle cell apoptosis, which was partially inhibited by anti-FasL antibody. We also tested the possibility that T helper (Th) 17, which is an IL-17-producing helper T-cell subset that plays crucial roles in autoimmune and inflammatory responses, participates in the pathogenesis of inflammatory myopathies. Interestingly, in vitro culturing of dendritic cells with anti-Fas immunoglobulin M (IgM) or activated CD4+ T cells induced the expression of mRNA for IL-23p19, but not for IL-12p35, in addition to proinflammatory cytokines. Furthermore, IL-23p19 and IL-17 mRNAs were detected in the majority of biopsy samples from patients with inflammatory myopathies. Taken together, these results suggest that proinflammatory cytokines enhance Fas-mediated apoptosis of muscle cells, and that the Fas/FasL interaction between invading dendritic cells and CD4+ T cells induces local production of IL-23 and proinflammatory cytokines, which can promote the proliferation of Th17 cells and enhance Fas-mediated apoptosis of muscle cells, respectively. [source] Apoptosis induction by interleukin-2-activated cytotoxic lymphocytes in a squamous cell carcinoma cell line and Daudi cells , involvement of reactive oxygen species-dependent cytochrome c and reactive oxygen species-independent apoptosis-inducing factorsIMMUNOLOGY, Issue 2 2003Tetsuya Yamamoto Summary Investigation of the induction of apoptosis by cytotoxic lymphocytes has mainly focused on the signalling associated with Fas and its adaptor proteins. The signal pathway via mitochondria, however, has not been sufficiently elucidated in cytotoxic lymphocyte-induced apoptosis. We examined the release of mitochondrial proapoptotic factors by lymphokine-activated killer (LAK) cells in two cell lines. LAK cell-induced DNA fragmentation of the target cells was suppressed to approximately 50% of control levels by the addition of neutralizing monoclonal antibody to Fas and a granzyme B inhibitor. When intracellular reactive oxygen species (ROS) were scavenged, the LAK cell-induced DNA fragmentation was decreased to approximately 60% of the non-treated cell level. Co-cultivation of Daudi cells with LAK cells increased cytosolic and mitochondrial ROS levels. Activation of procaspase-3 and apoptosis by treatment of oral squamous cell carcinoma cells (OSC) with LAK cells was partially inhibited by pretreatment of OSC cells with ROS scavengers and mitochondrial complex inhibitors. Furthermore, cytochrome c and apoptosis-inducing factor (AIF) were released from mitochondria by OSC cell treatment with supernatants of LAK cells. The supernatant-induced cytochrome c release was suppressed by mitochondrial complex inhibitors, but the inhibitors did not inhibit the release of AIF. These results indicate that LAK cells induce target cell apoptosis via not only the Fas/Fas ligand system and granzyme B, but also ROS-dependent cytochrome c and ROS-independent AIF release. [source] Probiotics and the management of inflammatory bowel diseaseINFLAMMATORY BOWEL DISEASES, Issue 3 2004FRCPC, Richard N. Fedorak MD Abstract The demonstration that immune and epithelial cells can discriminate between different microbial species has extended our understanding of the actions of probiotics beyond simple barrier and antimicrobial concepts. Several probiotic mechanisms of action, relative to inflammatory bowel disease, have been elucidated: (1) competitive exclusion, whereby probiotics compete with microbial pathogens for a limited number of receptors present on the surface epithelium; (2) immunomodulation and/or stimulation of an immune response of gut-associated lymphoid and epithelial cells; (3) antimicrobial activity and suppression of pathogen growth; (4) enhancement of barrier function; and (5) induction of T cell apoptosis in the mucosal immune compartment. The unraveling of these mechanisms of action has led to new support for the use of probiotics in the management of clinical inflammatory bowel disease. Though level 1 evidence now supports the therapeutic use of probiotics in the treatment of postoperative pouchitis, only levels 2 and 3 evidence is currently available in support of the use of probiotics in the treatment of ulcerative colitis and Crohn's disease. Nevertheless, one significant and consistent finding has emerged during the course of research in the past year: not all probiotic bacteria have similar therapeutic effects. Rigorously designed, controlled clinical trials are vital to investigate the unresolved issues related to efficacy, dose, duration of use, single or multi-strain formulation, and the concomitant use of prebiotics, synbiotics, or antibiotics. [source] Paternal transmission of genetic damage: findings in animals and humansINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 3 2000Martin H. Brinkworth The concept that mutations can be induced in the male germ-line and result in adverse effects in the offspring has achieved only limited acceptance despite considerable theoretical appeal. This is partly because fetal malformations are generally perceived to be induced solely as a result of maternally mediated events during gestation and partly because the low incidence of the end-points concerned make experimental approaches costly and time-consuming. Nonetheless, a substantial body of work relating to the hypothesis has accumulated in the last 20 years, which has never been reviewed in its entirety. A consideration of the available evidence indicates that preconceptional paternal exposure to mutagens (particularly radiation, cyclophosphamide and ethylnitrosourea) can indeed, under certain conditions, have adverse effects on offspring. The results suggest two principal mechanisms by which such effects may be induced: the induction of germ-line genomic instability or the suppression of germ cell apoptosis. [source] Identification of stemonamide synthetic intermediates as a novel potent anticancer drug with an apoptosis-inducing abilityINTERNATIONAL JOURNAL OF CANCER, Issue 2 2010Ying-Yi Li Abstract We previously demonstrated that Pim-3, a protooncogene with serine/threonine kinase activity, was aberrantly expressed in malignant lesions but not in normal tissues of endoderm-derived organs, including pancreas, liver, colon and stomach. Moreover, aberrantly expressed Pim-3 can prevent tumor cell apoptosis by inactivating a proapoptotic molecule, Bad, and enhancing the expression of an antiapoptotic molecule, Bcl-XL. These observations prompted us to speculate that a chemical targeting Pim-3 kinase may be a good candidate for a novel type of anticancer drug. Hence, we screened various low-molecule compounds by examining their capacity to inhibit Pim-3 kinase activity in vitro. We observed that some synthetic intermediates of stemonamide can inhibit in vitro activities of Pim-3 kinase and its related kinases, such as Pim-1 and Pim-2. Moreover, these compounds inhibit in vitro cell proliferation of various human pancreatic, hepatocellular and colon cancer cell lines. Furthermore, the compounds can induce apoptosis of human pancreatic cancer cell lines in vitro by reducing the amount of phospho-Ser112 -Bad, but not total amounts of Bad and Pim-3. Finally, when the compound was administered to nude mice injected with a human pancreatic cancer cell line, it retarded tumor growth by increasing apoptotic cell numbers and decreasing proliferating cell numbers without causing serious adverse effects on blood counts. These observations indicate that the chemicals and its related compounds may be effective for the treatment of tumors of endoderm-derived organs, particularly the pancreas. [source] Release of nucleophosmin from the nucleus: Involvement in aloe-emodin,induced human lung non small carcinoma cell apoptosisINTERNATIONAL JOURNAL OF CANCER, Issue 6 2005Hong-Zin Lee Abstract Aloe-emodin (1,8-dihydroxy-3-(hydroxymethyl)-anthraquinone) is one of the active constituents from the root and rhizome of Rheum palmatum. Our previous study has demonstrated that aloe-emodin induced a significant change in the expression of lung cancer cell apoptosis-related proteins compared to those of control cells. However, the molecular mechanisms underlying the biological effects of aloe-emodin still remain unknown. Based on these reasons, we were interested in the change of aloe-emodin,induced total protein expression by the proteomics technique during aloe-emodin,induced lung cancer cell apoptosis. Our study applied 2D electrophoresis to analyze the proteins involved in aloe-emodin,induced apoptosis in H460 cells. We found that the release of nucleophosmin from the nucleus to the cytosol and the degradation of nucleophosmin were associated with aloe-emodin,induced H460 cell apoptosis. Our study also demonstrated that the gene expression of nucleophosmin remained unchanged after treatment with aloe-emodin. The aloe-emodin,caused increase in the amount of proform and fragment of nucleophosmin in cytoplasm may be one of the important events for aloe-emodin,induced H460 cell apoptosis. © 2004 Wiley-Liss, Inc. [source] Hepatic effects of an open lung strategy and cardiac output restoration in an experimental lung injuryACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2010M. KREDEL Background: Ventilation with high positive end-expiratory pressure (PEEP) can lead to liver dysfunction. We hypothesized that an open lung concept (OLC) using high PEEP impairs liver function and integrity dependent on the stabilization of cardiac output. Methods: Juvenile female Pietrain pigs instrumented with flow probes around the common hepatic artery and portal vein, pulmonary and hepatic vein catheters underwent a lavage-induced lung injury. Ventilation was continued with a conventional approach (CON) using pre-defined combinations of PEEP and inspiratory oxygen fraction or with an OLC using PEEP set above the lower inflection point of the lung. Volume replacement with colloids was guided to maintain cardiac output in the CON(V+) and OLC(V+) groups or acceptable blood pressure and heart rate in the OLC(V,) group. Indocyanine green plasma disappearance rate (ICG-PDR), blood gases, liver-specific serum enzymes, bilirubin, hyaluronic acid and lactate were tested. Finally, liver tissue was examined for neutrophil accumulation, TUNEL staining, caspase-3 activity and heat shock protein 70 mRNA expression. Results: Hepatic venous oxygen saturation was reduced to 18 ± 16% in the OLC(V,) group, while portal venous blood flow decreased by 45%. ICG-PDR was not reduced and serum enzymes, bilirubin and lactate were not elevated. Liver cell apoptosis was negligible. Liver sinusoids in the OLC(V+) and OLC(V,) groups showed about two- and fourfold more granulocytes than the CON(V+) group. Heat shock protein 70 tended to be higher in the OLC(V,) group. Conclusions: Open lung ventilation elicited neutrophil infiltration, but no liver dysfunction even without the stabilization of cardiac output. [source] Influence for testicular development and histological peculiarity in the testes of flutamide-induced cryptorchid rat modelINTERNATIONAL JOURNAL OF UROLOGY, Issue 1 2007Kentaro Mizuno Objectives: To investigate influence for the testicular development and to assess the usefulness as an animal model, cryptorchid rats were induced by exposure to flutamide during the fetal period and their testes examined histologically. Methods: Flutamide was injected into the abdomen of pregnant rats for 7 days from the 14th to 20th day of gestation. The male offspring in which cryptorchidism was observed at 28 days after birth were defined as the model rats. They were divided into four groups by dosage of flutamide (2.5 mg, 5 mg, 7.5 mg, 15 mg per day), and their testicular weight, spermatogenesis (modified Johnsen score), and germ cell apoptosis were examined histochemically at 10 weeks after birth. Results: The incidence of cryptorchidism including both unilateral and bilateral in the 2.5, 5, 7.5 and 15-mg flutamide groups was 58.3%, 81.9%, 93.6% and 91.0%, respectively. In the model rats, the undescended testes were located at the caudal end of the abdominal cavity, and these testes weighed less than the contra-descended testes in each group. Histologically, apoptotic cells were markedly increased, the seminiferous tubules were degenerated and disturbance of spermatid differentiation was observed in the undescended testes compared with the normal or contra-lateral descended testes. Conclusions: We found out that the incidence of undescended testes increased in a flutamide dose-dependent manner. The findings of histological examination were independent of the administrated dose of flutamide and it is suggested that exposure of the testes to abdominal temperature causes spermatogenic arrest with germ cell apoptosis. The present animal model indicates high incidence of above 90%, has no surgical stress and dose not require special techniques. We believe that the present model is a useful tool for the understanding of pathogenesis and treatment of cryptorchidism and further biological research into spermatogenesis. [source] Bis(4,7-dimethyl and 5-dinitro-1,10-phenanthroline) sulfato-oxovanadium(IV)-mediated in vivo male germ cell apoptosisJOURNAL OF APPLIED TOXICOLOGY, Issue 4 2001Osmond J. D'Cruz Abstract Oxovanadium(IV) [VO] complexes of 1,10-phenanthroline are a new class of potent apoptosis-inducing cytotoxic agents against human testicular cancer cells in vitro. The present study investigated the in vivo ability of four(bis)-chelated 1,10-phenanthroline [phen] complexes of sulfato-oxovanadium(IV),VO(phen)2, VO(Cl,phen)2, VO(Me2,phen)2 and VO(NO2,phen)2,with and without substitutions, to induce testicular germ cell apoptosis. Male germ cell loss in mice was measured by determining the epididymal sperm count, testicular weight and histological evaluation of the testes. Repetitive intratesticular injection (7.5 mg kg,1 testis,1) of bis-chelated 1,10-phenanthroline complexes of oxovanadium(IV) with 4,7-dimethyl [VO(Me2,phen)2] and 5-dinitro [VO(NO2,phen)2] substitution led to decreased sperm counts and reduced testicular weights. Histopathological examination of testicular sections from VO(Me2,phen)2 - and VO(NO2,phen)2 -treated mice revealed a marked inhibition of spermatogenesis and preferential loss of maturing, as well as elongated spermatids. In situ evaluation of seminiferous tubule cross-sections by terminal deoxynucleotidyl transferase-mediated FITC-deoxyuridine triphosphate nick end-labeling (TUNEL) and laser scanning confocal microscopy showed characteristic apoptotic germ cells delineating the periphery of the seminiferous tubules. The ability of bis-chelated 4,7-dimethyl- and 5-dinitro-substituted 1,10-phenanthroline complexes of oxovanadium(IV) to induce germ cell apoptosis in vivo may have potential utility in the treatment of human testicular germ cell tumors. Copyright © 2001 John Wiley & Sons, Ltd. [source] GATA-3 transduces survival signals in osteoblasts through upregulation of bcl-xL gene expression,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2010Ruei-Ming Chen Abstract GATA-3, a transcription factor, participates in regulating cell development, proliferation, and death. This study was aimed at evaluating the roles of GATA-3 in protecting osteoblasts against oxidative stress,induced apoptotic insults and their possible mechanisms. Pretreatment with nitric oxide (NO) for 24 hours protected osteoblasts, prepared from neonatal rat calvaria, against oxidative stress,induced apoptotic insults. Such protection involved enhancement of Bcl-XL messenger (m)RNA and protein syntheses and the translocation of this antiapoptotic protein from the cytoplasm to mitochondria. GATA-3 was detected in rat osteoblasts, and GATA-3-specific DNA-binding elements exist in the promoter region of the bcl-xL gene. NO preconditioning attenuated oxidative stress,caused suppression of GATA-3 mRNA and protein synthesis and the translocation of this transcription factor from the cytoplasm to nuclei. Application of GATA-3 small interfering (si)RNA into osteoblasts decreased the levels of this transcription factor and simultaneously inhibited Bcl-XL mRNA synthesis. Pretreatment with NO lowered the oxidative stress,caused alteration in the binding of GATA-3 to its specific DNA motifs. Oxidative stress,inhibited Runx2 mRNA expression, but NO preconditioning decreased such inhibition. NO pretreatment time-dependently enhanced the association of GATA-3 with Runx2. Knocking down the translation of GATA-3 using RNA interference significantly decreased the protection of NO preconditioning against oxidative stress,induced alterations of cell morphologies, DNA fragmentation, and cell apoptosis. In comparison, overexpression of GATA-3 could promote NO preconditioning,involved Bcl-XL expression and cell survival. Therefore, this study shows that GATA-3 plays critical roles in mediating survival signals in osteoblasts, possibly through upregulating bcl-xL gene expression. © 2010 American Society for Bone and Mineral Research. [source] Role of the Bone Marrow Microenvironment in Multiple Myeloma,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2002G. David Roodman M.D., Ph.D. Abstract On June 26,27, 2001, the Sixth Research Roundtable in Multiple Myeloma, entitled "The Role of the Bone Microenvironment in Multiple Myeloma," was held and focused on the biology of cell-to-cell interactions, the mediators of bone disease, and novel treatment strategies for myeloma. Studies on cell-cell interactions showed that vascular cell adhesion molecule 1, expressed by local endothelial and stromal cells, binds to tumor cell surface integrins in which expression may be increased by tumor cell-derived chemokines such as macrophage inflammatory protein (MIP) 1,. These adhesive interactions increase production and release of vascular endothelial growth factor (VEGF). Studies on myeloma bone disease showed the ligand for receptor activator of nuclear transcription factor-,B (RANKL) was expressed on tumor cells and stromal cells associated with myeloma cells and was critical for osteoclast-induced osteolysis. Blockade of RANKL suppressed osteoclast maturation, bone resorption, and tumor development. Bisphosphonates, in addition to reducing osteoclast mobility and inducing osteoclast apoptosis, also decreased tumor cell adhesion to stroma. Immunomodulatory drugs such as thalidomide analogues targeted these tumor cell-stromal cell interactions, blocking both secretion of cytokines and activation of intracellular signaling pathways required for tumor survival and growth. These agents induced tumor cell apoptosis, decreased neovascularization, and potentiated natural killer cell activity. The proteasome inhibitor PS-341 also prevented expression of adhesion molecules and cytokines and triggered tumor cell apoptosis, even in drug-resistant cell lines, while showing minimal activity in healthy cells. In addition, potential therapeutic agents under investigation, which included RANKL antagonists, protein prenylation inhibitors, and osteoblast growth factors, were discussed. [source] H2S-induced pancreatic acinar cell apoptosis is mediated via JNK and p38 MAP kinaseJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2008Sharmila Adhikari Abstract Treatment of pancreatic acinar cells by hydrogen sulphide has been shown to induce apoptosis. However, a potential role of mitogen-activated protein kinases (MAPKs) in this apoptotic pathway remains unknown. The present study examined the role of MAPKs in H2S-induced apoptosis in mouse pancreatic acinar cells. Pancreatic acinar cells were treated with 10 ,M NaHS (a donor of H2S) for 3 hrs. For the evaluation of the role of MAPKs, PD98059, SP600125 and SB203580 were used as MAPKs inhibitors for ERK1/2, JNK1/2 and p38 MAPK, respectively. We observed activation of ERK1/2, JNK1/2 and p38 when pancreatic acini were exposed to H2S. Moreover, H2S-induced ERK1/2, JNK1/2 and p38 activation were blocked by pre-treatment with their corresponding inhibitor in a dose-dependent manner. H2S-induced apoptosis led to an increase in caspase 3 activity and this activity was attenuated when caspase 3 inhibitor were used. Also, the cleavage of caspase 3 correlated with that of poly-(ADP-ribose)-polymerase (PARP) cleavage. H2S treatment induced the release of cytochrome c, smac from mitochondria into the cytoplasm, translocation of Bax into mitochondria and decreased the protein level of Bcl-2. Inhibition of ERK1/2 using PD98059 caused further enhancement of apoptosis as evidenced by annexin V staining, while SP600125 and SB203580 abrogated H2S-induced apoptosis. Taken together, the data suggest that activation of ERKs promotes cell survival, whereas activation of JNKs and p38 MAP kinase leads to H2S-induced apoptosis. [source] | |||||||||||||||||||||||||||||||||||||