58 research outputs found

    Treatment of CoQ10 Deficient Fibroblasts with Ubiquinone, CoQ Analogs, and Vitamin C: Time- and Compound-Dependent Effects

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    Background: Coenzyme Q(10) (CoQ(10)) and its analogs are used therapeutically by virtue of their functions as electron carriers, antioxidant compounds, or both. However, published studies suggest that different ubiquinone analogs may produce divergent effects on oxidative phosphorylation and oxidative stress.Methodology/Principal Findings: To test these concepts, we have evaluated the effects of CoQ(10), coenzyme Q(2) (CoQ(2)), idebenone, and vitamin C on bioenergetics and oxidative stress in human skin fibroblasts with primary CoQ(10) deficiency. A final concentration of 5 mu M of each compound was chosen to approximate the plasma concentration of CoQ(10) of patients treated with oral ubiquinone. CoQ(10) supplementation for one week but not for 24 hours doubled ATP levels and ATP/ADP ratio in CoQ(10) deficient fibroblasts therein normalizing the bioenergetics status of the cells. Other compounds did not affect cellular bioenergetics. In COQ2 mutant fibroblasts, increased superoxide anion production and oxidative stress-induced cell death were normalized by all supplements.Conclusions/Significance: These results indicate that: 1) pharmacokinetics of CoQ(10) in reaching the mitochondrial respiratory chain is delayed; 2) short-tail ubiquinone analogs cannot replace CoQ(10) in the mitochondrial respiratory chain under conditions of CoQ(10) deficiency; and 3) oxidative stress and cell death can be counteracted by administration of lipophilic or hydrophilic antioxidants. The results of our in vitro experiments suggest that primary CoQ(10) deficiencies should be treated with CoQ(10) supplementation but not with short-tail ubiquinone analogs, such as idebenone or CoQ(2). Complementary administration of antioxidants with high bioavailability should be considered if oxidative stress is present

    A Novel Therapy for Melanoma Developed in Mice: Transformation of Melanoma into Dendritic Cells with Listeria monocytogenes

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    Listeria monocytogenes is a gram-positive bacteria and human pathogen widely used in cancer immunotherapy because of its capacity to induce a specific cytotoxic T cell response in tumours. This bacterial pathogen strongly induces innate and specific immunity with the potential to overcome tumour induced tolerance and weak immunogenicity. Here, we propose a Listeria based vaccination for melanoma based in its tropism for these tumour cells and its ability to transform in vitro and in vivo melanoma cells into matured and activated dendritic cells with competent microbicidal and antigen processing abilities. This Listeria based vaccination using low doses of the pathogen caused melanoma regression by apoptosis as well as bacterial clearance. Vaccination efficacy is LLO dependent and implies the reduction of LLO-specific CD4+ T cell responses, strong stimulation of innate pro-inflammatory immune cells and a prevalence of LLO-specific CD8+ T cells involved in tumour regression and Listeria elimination. These results support the use of low doses of pathogenic Listeria as safe melanoma therapeutic vaccines that do not require antibiotics for bacterial removal

    The Evolution of a Female Genital Trait Widely Distributed in the Lepidoptera: Comparative Evidence for an Effect of Sexual Coevolution

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    Sexual coevolution is considered responsible for the evolution of many male genital traits, but its effect on female genital morphology is poorly understood. In many lepidopterans, females become temporarily unreceptive after mating and the length of this refractory period is inversely related to the amount of spermatophore remaining in their genital tracts. Sperm competition can select for males that delay female remating by transferring spermatophores with thick spermatophore envelopes that take more time to be broken. These envelopes could select for signa, sclerotized sharp structures located within the female genital tract, that are used for breaking spermatophores. Thus, this hypothesis predicts that thick spermatophore envelopes and signa evolve in polyandrous species, and that these adaptations are lost when monandry evolves subsequently. Here we test the expected associations between female mating pattern and presence/absence of signa, and review the scant information available on the thickness of spermatophore envelopes.We made a literature review and found information on female mating pattern (monandry/polyandry), presence/absence of signa and phylogenetic position for 37 taxa. We built a phylogenetic supertree for these taxa, mapped both traits on it, and tested for the predicted association by using Pagel's test for correlated evolution. We found that, as predicted by our hypothesis, monandry evolved eight times and in five of them signa were lost; preliminary evidence suggests that at least in two of the three exceptions males imposed monandry on females by means of specially thick spermatophore envelopes. Previously published data on six genera of Papilionidae is in agreement with the predicted associations between mating pattern and the characteristics of spermatophore envelopes and signa.Our results support the hypothesis that signa are a product of sexually antagonistic coevolution with spermatophore envelopes

    Amifostine reduces the seminiferous epithelium damage in doxorubicin-treated prepubertal rats without improving the fertility status

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    <p>Abstract</p> <p>Background</p> <p>Amifostine is an efficient cytoprotector against toxicity caused by some chemotherapeutic drugs. Doxorubicin, a potent anticancer anthracycline, is known to produce spermatogenic damage even in low doses. Although some studies have suggested that amifostine does not confer protection to doxorubicin-induced testicular damage, schedules and age of treatment have different approach depending on the protocol. Thus, we proposed to investigate the potential cytoprotective action of amifostine against the damage provoked by doxorubicin to prepubertal rat testes (30-day-old) by assessing some macro and microscopic morphometric parameters 15, 30 and 60 days after the treatment; for fertility evaluation, quantitative analyses of sperm parameters and reproductive competence in the adult phase were also carried out.</p> <p>Methods</p> <p>Thirty-day-old male rats were distributed into four groups: Doxorubicin (5 mg/kg), Amifostine (400 mg/kg), Amifostine/Doxorubicin (amifostine 15 minutes before doxorubicin) and Sham Control (0.9% saline solution). "Standard One Way Anova" parametric and "Anova on Ranks" non-parametric tests were applied according to the behavior of the obtained data; significant differences were considered when p < 0.05.</p> <p>Results</p> <p>The rats killed 30 and 60 days after doxorubicin treatment showed diminution of seminiferous epithelium height and reduction on the frequency of tubular sections containing at least one type of differentiated spermatogonia; reduction of sperm concentration and motility and an increase of sperm anomalous forms where observed in doxorubicin-treated animals. All these parameters were improved in the Amifostine/Doxorubicin group only when compared to Doxorubicin group. Such reduction, however, still remained below the values obtained from the Sham Control group. Nevertheless, the reproductive competence of doxorubicin-treated rats was not improved by amifostine pre-administration.</p> <p>Conclusions</p> <p>These results suggest that amifostine promotes a significant reduction of the doxorubicin long-term side effects on the seminiferous epithelium of prepubertal rats, which is reflected in the epidydimal fluid parameters in the adult phase. However, fertility status results suggest that such protection may not be effective against sperm DNA content damage. Further investigation of sperm DNA integrity must be carried out using amifostine and doxorubicin-treated experimental models.</p

    Beyond Genetic Factors in Familial Amyloidotic Polyneuropathy: Protein Glycation and the Loss of Fibrinogen's Chaperone Activity

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    Familial amyloidotic polyneuropathy (FAP) is a systemic conformational disease characterized by extracellular amyloid fibril formation from plasma transthyretin (TTR). This is a crippling, fatal disease for which liver transplantation is the only effective therapy. More than 80 TTR point mutations are associated with amyloidotic diseases and the most widely accepted disease model relates TTR tetramer instability with TTR point mutations. However, this model fails to explain two observations. First, native TTR also forms amyloid in systemic senile amyloidosis, a geriatric disease. Second, age at disease onset varies by decades for patients bearing the same mutation and some mutation carrier individuals are asymptomatic throughout their lives. Hence, mutations only accelerate the process and non-genetic factors must play a key role in the molecular mechanisms of disease. One of these factors is protein glycation, previously associated with conformational diseases like Alzheimer's and Parkinson's. The glycation hypothesis in FAP is supported by our previous discovery of methylglyoxal-derived glycation of amyloid fibrils in FAP patients. Here we show that plasma proteins are differentially glycated by methylglyoxal in FAP patients and that fibrinogen is the main glycation target. Moreover, we also found that fibrinogen interacts with TTR in plasma. Fibrinogen has chaperone activity which is compromised upon glycation by methylglyoxal. Hence, we propose that methylglyoxal glycation hampers the chaperone activity of fibrinogen, rendering TTR more prone to aggregation, amyloid formation and ultimately, disease

    Functional Analysis of the Arlequin Mutant Corroborates the Essential Role of the ARLEQUIN/TAGL1 Gene during Reproductive Development of Tomato

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    Reproductive development of higher plants comprises successive events of organ differentiation and growth which finally lead to the formation of a mature fruit. However, most of the genetic and molecular mechanisms which coordinate such developmental events are yet to be identified and characterized. Arlequin (Alq), a semi-dominant T-DNA tomato mutant showed developmental changes affecting flower and fruit ripening. Sepals were converted into fleshy organs which ripened as normal fruit organs and fruits displayed altered ripening features. Molecular characterization of the tagged gene demonstrated that it corresponded to the previously reported TOMATO AGAMOUS-LIKE 1 (TAGL1) gene, the tomato ortholog of SHATTERPROOF MADS-box genes of Arabidopsis thaliana, and that the Alq mutation promoted a gain-of-function phenotype caused by the ectopic expression of TAGL1. Ectopic overexpression of TAGL1 resulted in homeotic alterations affecting floral organ identity that were similar to but stronger than those observed in Alq mutant plants. Interestingly, TAGL1 RNAi plants yielded tomato fruits which were unable to ripen. They displayed a yellow-orange color and stiffness appearance which are in accordance with reduced lycopene and ethylene levels, respectively. Moreover, pericarp cells of TAGL1 RNAi fruits showed altered cellular and structural properties which correlated to both decreased expression of genes regulating cell division and lignin biosynthesis. Over-expression of TAGL1 is able to rescue the non-ripening phenotype of rin and nor mutants, which is mediated by the transcriptional activation of several ripening genes. Our results demonstrated that TAGL1 participates in the genetic control of flower and fruit development of tomato plants. Furthermore, gene silencing and over-expression experiments demonstrated that the fruit ripening process requires the regulatory activity of TAGL1. Therefore, TAGL1 could act as a linking factor connecting successive stages of reproductive development, from flower development to fruit maturation, allowing this complex process to be carried out successfully
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