eIF5A binds to translational machinery components and affects translation in yeast

The putative translation factor eIF5A is essential for cell viability and is highly conserved from archebacteria to mammals. Although this protein was originally identified as a translation initiation factor, subsequent experiments did not support a role for eIF5A in general translation. In this work, we demonstrate that eIF-5A interacts with structural components of the 80S ribosome, as well as with the translation elongation factor 2 (eEF2). Moreover, eIF5A is further shown to cofractionate with monosomes in a translation-dependent manner. Finally, eIF5A mutants show altered polysome profiles and are sensitive to translation inhibitors. Our results re-establish a function for eIF5A in translation and suggest a role for this factor in translation elongation instead of translation initiation. (c) 2006 Elsevier B.V. All rights reserved.

Antibodies to yeast Sm motif 1 cross-react with human Sm core polypeptides

Two regions common to all UsnRNP core polypeptides have been described: Sm motif 1 and Sm motif 2. Rabbits were immunized with a 22 amino-acid peptide containing one segment of Sm motif 1 (YRGTLVSTDNYFNLQL-NEAEEF, corresponding to residues 11-32) from yeast F protein. After immunization, the rabbit sera contained antibodies that not only reacted specifically with the peptide from yeast F protein but also cross-reacted with Sm polypeptides from mammals; that is, with purified human U1snRNPs. The results suggest that the peptide used and human Sm polypeptides contain a common feature recognized by the polyclonal antibodies. A large collection of human systemic lupus erythematosus sera was assayed using the yeast peptide as an antigen source. Seventy per cent of systemic lupus erythematosus sera contain an antibody specificity that cross-reacts with the yeast peptide.

Alkaloids extracted from Pterogyne nitens induce apoptosis in malignant breast cell line

In the present study, two alkaloids isolated from Pterogyne nitens, a plant native to Brazil, have been shown to induce apoptosis in human breast cancer cells. These compounds, pterogynine (PGN) and pterogynidine (PGD), were tested for their effect on a human infiltrating ductal carcinoma cell line (ZR-7531). The cell line was treated with each alkaloid at several concentrations. Time-dependence (with or without recuperation time) and concentration-dependence (in the range 0.25-10 mM) were investigated in cytotoxicity and apoptosis assays. The annexin assay indicated an apparently higher percentage of death by necrosis of malignant cells after 24 h exposure to both P. nitens extracts than the Hoechst assay. Thus, our results in the two tests demonstrated that the Hoechst assay can discriminate between late apoptotic cells and necrosis, whereas the flow cytometry-based annexin V assay cannot. We concluded that PGN and PGD have effective antineoplastic activity against human breast cancer cells in vitro, by inducing programmed cell death.

Lower levels of oxidative DNA damage and apoptosis in lymphocytes from patients undergoing surgery with propofol anesthesia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Erythropoietin Attenuates Apoptosis After Ischemia-Reperfusion-Induced Renal Injury in Transiently Hyperglycemic Wister Rats

Background. Hyperglycemia is associated with a decreased tolerance to ischemia and an increased severity of renal ischemia reperfusion (I/R) injury. It has been suggested that erythropoietin (EPO) attenuates this effect in normoglycemic animals. This study sought to examine the effects of EPO on treatment renal I/R injury (IRI) in transiently hyperglycemic rats.Material and Methods. Twenty-eight male Wister rats anesthetized with isoflurane received glucose (2.5 g.kg(-1) intraperitoneally) before right nephrectomy. They were randomly assigned to four groups: sham operation (S); IRI (ISO); IRI+EPO, (600 UI kg(-1) low-dose EPO [EL]); and IRI+EPO 5000 UI kg(-1) (high-dose EPO [EH]). IRI was induced by a 25-minute period of left renal ischemia followed by reperfusion for 24 hours. Serum Creatinine and glucose levels were measure at baseline (M1), immediately after the ischemic period (M2), and at 24 hours after reperfusion (M3). After sacrificing the animals, left kidney specimens were submitted for histological analysis including flow cytometry to estimate tubular necrosis and the percentages of apoptotic, dead or intact cells.Results. Scr in the ISO group was significantly higher at M3 than among the other groups. Percentages of early apoptotic cells in ISO group were significantly higher than the other groups. Percentages of late apoptotic cells in S and ISO groups were significantly greater than EL and EH groups. However, no significant intergroup differences were observed regarding the incidence of tubular necrosis.Conclusions. Our results suggested that, although not preventing the occurrence of tubular necrosis, EPO attenuated apoptosis and glomerular functional impairment among transiently hyperglycemic rats undergoing an ischemia/reperfusion insult.

Killing of Paracoccidioides brasiliensis yeast cells by IFN-gamma and TNF-alpha activated murine peritoneal macrophages: evidence of H(2)O(2) and NO effector mechanisms

Paracoccidioidomycosis is a deep mycosis, endemic in Latin America, caused by Paracoccidioides brasiliensis. Macrophage activation by cytokines is the major effector mechanism against this fungus. This work aimed at a better understanding of the interaction between yeast cells-murine peritoneal macrophages and the cytokine signals required for the effective killing of high virulence yeast-form of P. brasiliensis. In addition, the killing effector mechanisms dependent on the generation of reactive oxygen or nitrogen intermediates were investigated. Cell preincubation with IFN-gamma or TNF-alpha, at adequate doses, resulted in effective yeast killing as demonstrated in short-term (4-h) assays. Both, IFN-gamma and TNF-alpha activation were associated with higher levels of H(2)O(2) and NO when compared to nonactivation. Treatment with catalase (CAT), a H(2)O(2) scavenger, and N(G)-monomethyl-L-arginine (L-NMMA), a nitric oxide synthase inhibitor, reverted the killing effect of activated cells. Taken together, these results suggest that both oxygen and L-arginine-nitric oxide pathways play a role in the killing of highly virulent P. brasiliensis.

Changes in apoptosis and Bcl-2 expression in human hyperglycemic, term placental trophoblast

Apoptosis and its associated regulatory mechanisms are physiological events crucial to the maintenance of placental homeostasis; imbalance of these processes, however, such as occurs under various pathological conditions, may compromise placenta function and, consequently, pregnancy success. Increased apoptosis occurs in the placentas of pregnant women with several developmental disabilities, while increased Bcl-2 expression is generally associated with pregnancy-associated tumors. Herein, we tested the hypothesis that apoptosis-associated disturbs might be involved in the placental physiopathology subjected to different maternal hyperglycemic conditions.Thus, in the present study we investigated and compared the incidence of apoptosis using TUNEL reaction and Bcl-2 expression, in term-placentas of normoglycemic, diabetic and daily hyperglycemic patients. Tissue samples were collected from 37 placentas, being 15 from healthy mothers with normally delivered healthy babies, and 22 from mothers with glucose disturbances. From these latter 22 patients, 10 showed maternal daily hyperglycemia and 12 were clinically diabetics. Both Bcl-2 expression and apoptotic DNA fragmentation were established and quantified in the trophoblasts of healthy mothers. Compared to these reference values, a higher apoptosis index and lower Bcl-2 expression were disclosed in the placentas of the diabetic women, while in the daily hyperglycemic group, values were intermediate between the diabetic and normoglycemic patients. The TUNEL/Bcl-2 index ratio in the placentas varied from 0.02 to 0.09 for pregnant normoglycemic and diabetic women, respectively, revealing a predominance of apoptosis in the diabetic group. Our findings suggest that hyperglycemia may be a key factor evoking apoptosis in the placental trophoblast, and therefore, is relevant to diabetic placenta function. (c) 2006 Elsevier B.V.. All rights reserved.

Evaluation of Cell Proliferation and Apoptosis in Placentas of Rats with Severe Diabetes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

TRAIL-R3-related apoptosis: Epigenetic and expression analyses in women with ovarian neoplasia

Objective. To assess the expression of TRAIL-R3 and the methylation of a CpG island within the TRAIL-R3 promoter both in cystadenoma tumors and primary and metastatic epithelial ovarian carcinoma (EOC).Methods. RNA was obtained from women with normal ovarian (NO) tissues (n = 18), ovarian serous cystadenoma tumors (n = 11) and EOC (n = 16) using Trizol (R). Quantitative PCR (gRT-PCR) was performed to quantify the relative levels of TRAIL-R3. The methylation frequency of the CpG island in the TRAIL-R3 promoter was assessed using the methylation-specific PCR (MSP) assay after DNA bisulfite conversion. The differences between the groups were evaluated using the chi-square, Student's t, ANOVA, Mann-Whitney U, Wilcoxon or Kruskal-Wallis tests as indicated. The survival rates were calculated using the Kaplan-Meier method.Results. Cystadenoma and metastatic EOC tumors expressed significantly more TRAIL-R3 mRNA than primary EOC tumors. Methylation of the TRAIL-R3 promoter was absent in NO tissues, while hemimethylation of the TRAIL-R3 promoter was frequently found in the neoplasia samples with 45.4% of the cystadenoma tumors, 8.3% of the primary EOC samples and 11.1% of the metastatic EOC samples showing at least partial methylation (p = 0.018). Neither the expression of TRAIL-R3 nor alterations in the methylation profile were associated to cumulative progression-free survival or the overall survival in EOC patients.Conclusions. Primary EOC is associated to a lower TRAIL-R3 expression, which leads to a better understanding of the complex disease and highlighting potential therapeutic targets. Promoter DNA methylation was not related to this finding, suggesting the presence of other mechanisms to transcriptional control. (C) 2012 Elsevier B.V. All rights reserved.

GnRH agonist versus GnRH antagonist in IVF/ICSI cycles with recombinant LH supplementation: DNA fragmentation and apoptosis in granulosa cells

Objective: To compare the level of apoptosis and DNA fragmentation in the human granulosa cell (GC) layer exposed to an agonist or antagonist of GnRH in intracytoplasmic sperm injection (ICSI) cycles supplemented with recombinant LH (rLH).Study design: Patients without ovulatory dysfunction, aged <= 37 years and in their first ICSI cycle were prospectively randomised to receive either a long GnRH agonist protocol or a multi-dose antagonist protocol. In both groups, recombinant FSH supplemented with rLH was used for ovarian stimulation, and the GCs were collected during oocyte denudation. The GCs were then analysed for DNA fragmentation by TUNEL assay and for apoptosis using the annexin-V assay. The outcomes were given as the percentage of GCs with DNA fragmentation and apoptosis out of the total number of GCs analysed. Comparison of the agonist versus the antagonist group was performed using the Mann-Whitney test.Results: DNA fragmentation: 32 patients were included in either the GnRH agonist group (n = 16) or the antagonist group (n = 16). The percentage of GCs with positive DNA fragmentation did not differ significantly (P = 0.76) between the agonist group (15.5 +/- 9.4%) and the antagonist group (18.8 +/- 13.3%). Apoptosis: 28 patients were included in either the GnRH agonist group (n = 14) or the antagonist group (n = 14). The percentage of GCs positive for apoptosis did not differ significantly (P = 0.78) between the agonist group (34.6 +/- 14.7%) and the antagonist group (36.5 +/- 22%).Conclusions: The results suggest that therapy with either an agonist or antagonist of GnRH is associated with comparable levels of DNA fragmentation and apoptosis in granulosa cells in ICSI cycles supplemented with rLH. (C) 2012 Elsevier B.V. All rights reserved.

Effects of uracil calculi on cell growth and apoptosis in the BBN-initiated Wistar rat urinary bladder mucosa

The different potential of initiated and non-initiated urinary bladder mucosa (UBM) to develop neoplasia was quantitatively evaluated in the male Wistar rat. Initiation of carcinogenesis was accomplished with N-butyl-N- (4-hydroxybutyl) -nitrosamine (BBN). Stimuli for cell proliferation and apoptosis were obtained by exposure followed by withdrawal of 3% Uracil in the diet. The proliferation index (PI) was estimated in UBM immunostained for the proliferating nuclear cell antigen (PCNA). The apoptotic index (AI) and the density of papillary/nodular hyperplasia (PNH) were estimated in hematoxilin-eosin stained sections. PNH was the main proliferative response to the mechanical irritation by uracil, irrespective of previous initiation with BBN. Uracil exposure induced higher PI and PNH density in the initiated rats. After uracil withdrawal, there was a significant increase of the AI in both uracil-treated groups, which correlated well to the respective PNH density. However, at the end of the experiment, PNH incidence and density were significantly higher in the BBN-initiated mucosa, which also presented 18% incidence of papillomas and 27% of carcinomas. Therefore, under prolonged uracil calculi trauma, the UBM of BBN-initiated Wistar rats gives rise to epithelial proliferative lesions that progress to neoplasia through acquired resistance to apoptosis. (C) 1999 Wiley-Liss, Inc.

Cigarette smoke affects apoptosis in rat tongue mucosa: Role of bcl-2 gene family

While it has been clearly demonstrated that smoking is the most significant exogenous factor involved in oral carcinogenesis, little is known about the global molecular and cellular changes that occur prior to the appearance of clinically detectable symptoms. Thus, the aim of this study was to investigate the expressivity of bcl-2, bax and PCNA in the rat tongue mucosa exposed to cigarette smoke by means of immunohistochemistry. A total of twelve male Wistar rats were distributed into 2 groups: negative control and experimental group exposed to cigarette smoke during 75 days. After experimental period, no histopathological changes in the tongue mucosa were detected in the negative control and the experimental group. on the other hand, an overexpression of bcl-2 was detected (p < 0.01) throughout all layers of the epithelium, whereas bax did not show significant differences (p > 0.05). Also, the labeling index for bcl-2 and bax showed an increase 75 days after cigarette exposure (p < 0.01). PCNA-labeling index did not show remarkable changes between groups. Taken together, our results show that bcl-2 is overexpressed in the rat tongue keratinocytes after cigarette smoke exposure.