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1.
Chem Biol Interact ; 281: 89-97, 2018 Feb 01.
Article in English | MEDLINE | ID: mdl-29273566

ABSTRACT

Melanoma incidence increases every year worldwide and is responsible for 80% of skin cancer deaths. Due to its metastatic potential and resistance to almost any treatments such as chemo, radio, immune and targeted-therapy, the patients still have a poor prognosis, especially at metastatic stage. Considering that, it is crucial to find new therapeutic approaches to overcome melanoma resistance. Here we investigated the effect of cisplatin (CDDP), one of the chemotherapeutic agents used for melanoma treatment, in association with nutritional deprivation in murine melanoma cell lines. Cell death and autophagy were evaluated after the treatment with cisplatin, nutritional deprivation and its association using an in vitro model of murine melanocytes malignant transformation to metastatic melanoma. Our results showed that nutritional deprivation augmented cell death induced by cisplatin in melanoma cells, especially at the metastatic subtype, with slight effects on melanocytes. Mechanistic studies revealed that although autophagy was present at high levels in basal conditions in melanoma cells, was not essential for cell death process that involved mitochondrial damage, reactive oxygen species production and possible glycolysis inhibition. In conclusion, nutritional shortage in combination with chemotherapeutic drugs as cisplatin can be a valuable new therapeutic strategy to overcome melanoma resistance.


Subject(s)
Apoptosis/drug effects , Autophagy/drug effects , Cisplatin/pharmacology , Animals , Autophagy-Related Protein 7/antagonists & inhibitors , Autophagy-Related Protein 7/genetics , Autophagy-Related Protein 7/metabolism , Cell Line , Glucose/metabolism , Macrolides/pharmacology , Melanocytes/cytology , Melanocytes/drug effects , Melanocytes/metabolism , Melanoma/metabolism , Melanoma/pathology , Membrane Potentials/drug effects , Mice , Microscopy, Fluorescence , Microtubule-Associated Proteins/metabolism , RNA Interference , RNA, Small Interfering/metabolism , Reactive Oxygen Species/metabolism
2.
Eur J Neurosci ; 40(3): 2471-8, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24827147

ABSTRACT

Although the accumulation of the neurotoxic peptide ß-amyloid (Aß) in the central nervous system is a hallmark of Alzheimer's disease, whether Aß acts in astrocytes is unclear, and downstream functional consequences have yet to be defined. Here, we show that cytosolic Ca(2+) dysregulation, induced by a neurotoxic fragment (Aß25-35), caused apoptosis in a concentration-dependent manner, leading to cytoplasmic Ca(2+) mobilization from extra- and intracellular sources, mainly from the endoplasmic reticulum (ER) via IP3 receptor activation. This mechanism was related to Aß-mediated apoptosis by the intrinsic pathway because the expression of pro-apoptotic Bax was accompanied by its translocation in cells transfected with GFP-Bax. Aß-mediated apoptosis was reduced by BAPTA-AM, a fast Ca(2+) chelator, indicating that an increase in intracellular Ca(2+) was involved in cell death. Interestingly, the Bax translocation was dependent on Ca(2+) mobilization from IP3 receptors because pre-incubation with xestospongin C, a selective IP3 receptor inhibitor, abolished this response. Taken together, these results provide evidence that Aß dysregulation of Ca(2+) homeostasis induces ER depletion of Ca(2+) stores and leads to apoptosis; this mechanism plays a significant role in Aß apoptotic cell death and might be a new target for neurodegeneration treatments.


Subject(s)
Amyloid beta-Peptides/pharmacology , Apoptosis/drug effects , Astrocytes/drug effects , Astrocytes/metabolism , Calcium Signaling/drug effects , Inositol 1,4,5-Trisphosphate Receptors/metabolism , Peptide Fragments/pharmacology , Alzheimer Disease/metabolism , Animals , Cells, Cultured , Endoplasmic Reticulum/drug effects , Endoplasmic Reticulum/metabolism , Rats , Signal Transduction
3.
Chem Biol Interact ; 206(2): 279-88, 2013 Nov 25.
Article in English | MEDLINE | ID: mdl-24121004

ABSTRACT

Autophagy is a mechanism of protection against various forms of human diseases, such as cancer, in which autophagy seems to have an extremely complex role. In cancer, there is evidence that autophagy may be oncogenic in some contexts, whereas in others it clearly contributes to tumor suppression. In addition, studies have demonstrated the existence of a complex relationship between autophagy and cell death, determining whether a cell will live or die in response to anticancer therapies. Nevertheless, we still need to complete the autophagy-apoptosis puzzle in the tumor context to better address appropriate chemotherapy protocols with autophagy modulators. Generally, tumor cell resistance to anticancer induced-apoptosis can be overcome by autophagy inhibition. However, when an extensive autophagic stimulus is activated, autophagic cell death is observed. In this review, we discuss some details of autophagy and its relationship with tumor progression or suppression, as well as role of autophagy-apoptosis in cancer treatments.


Subject(s)
Apoptosis , Autophagy , Neoplasms/drug therapy , Antineoplastic Agents/therapeutic use , Cell Communication , Drug Resistance, Neoplasm , Humans , Molecular Chaperones/metabolism , Neoplasm Metastasis , Neoplasms/metabolism , Neoplasms/pathology
5.
Curr Mol Med ; 13(2): 252-65, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23228221

ABSTRACT

The mechanisms that regulate programmed cell death, such as apoptosis, and the cellular "self-eating" phenomenon of autophagy, share many regulatory systems and common pathways. These mechanisms have been extensively investigated over the last few years. Some intracellular structures may determine and control the autophagic fate of the cell such as the endoplasmic reticulum, mitochondria, and lysosomes. The coordination and interrelation of these organelles are crucial in maintaining calcium levels and general cellular homeostasis, as well as in regulating cell life and death under physiological and pathological conditions, including cancer, neurodegeneration, and aging. In this review, we discuss the crosstalk between the aforementioned organelles and their influence in apoptotic and autophagic processes.


Subject(s)
Aging/genetics , Calcium/metabolism , Endoplasmic Reticulum/metabolism , Lysosomes/metabolism , Mitochondria/metabolism , Aging/metabolism , Animals , Apoptosis/genetics , Autophagy/genetics , Endoplasmic Reticulum/genetics , Gene Expression Regulation , Homeostasis , Humans , Lysosomes/genetics , Mitochondria/genetics , Neoplasms/genetics , Neoplasms/metabolism , Neoplasms/pathology , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/metabolism , Neurodegenerative Diseases/pathology , Signal Transduction
7.
Curr Pharm Des ; 17(35): 3865-77, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21933141

ABSTRACT

Glutamate is an important neurotransmitter in neurons and glial cells and it is one of the keys to the neuron-glial interaction in the brain. Glutamate transmission is strongly dependent on calcium homeostasis and on mitochondrial function. In the present work we presented several aspects related to the role of mitochondria in glutamate signaling and in brain diseases. We focused on glutamateinduced calcium signaling and its relation to the organelle dysfunction with cell death processes. In addition, we have discussed how alterations in this pathway may lead or aggravate a variety of neurodegenerative diseases. We compiled information on how mitochondria can influence cell fate during glutamate stimulation and calcium signaling. These organelles play a pivotal role in neuron and glial exchange, in synaptic plasticity and several pathological conditions related to Aging, Alzheimer's, Parkinson's and Huntington's diseases. We have also presented autophagy as a mechanism activated during mitochondrial dysfunction which may function as a protective mechanism during injury. Furthermore, some new perspectives and approaches to treat these neurodegenerative diseases are offered and evaluated.


Subject(s)
Energy Metabolism , Glutamic Acid/metabolism , Mitochondria/metabolism , Neuroglia/metabolism , Neurons/metabolism , Synaptic Transmission , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Animals , Autophagy/drug effects , Calcium Signaling/drug effects , Energy Metabolism/drug effects , Excitatory Amino Acid Agents/metabolism , Excitatory Amino Acid Agents/pharmacology , Humans , Huntington Disease/drug therapy , Huntington Disease/metabolism , Mitochondria/drug effects , Neuroglia/drug effects , Neuronal Plasticity/drug effects , Neurons/drug effects , Neurotoxicity Syndromes/drug therapy , Neurotoxicity Syndromes/metabolism , Neurotoxicity Syndromes/prevention & control , Parkinson Disease/drug therapy , Parkinson Disease/metabolism , Synaptic Transmission/drug effects
8.
Neurochem Res ; 36(5): 829-38, 2011 May.
Article in English | MEDLINE | ID: mdl-21347840

ABSTRACT

Apoptosis is a highly complex form of cell death that can be triggered by alterations in Ca(2+) homeostasis. Members of the Bcl-2 family may regulate apoptosis and modulate Ca(2+) distribution within intracellular compartments. Bax, a proapoptotic member of the family, is constitutively expressed and soluble in the cytosol and, under apoptotic induction, translocates to mitochondrial membranes. However, it is not clear if the intracellular Ca(2+) stores and selective Ca(2+) releases can modulate or control Bax translocation. The aim of this study was to investigate the relation of intracellular Ca(2+) stores with Bax translocation in rat cortical astrocytes. Results show that the classical apoptotic inducer, staurosporine, caused high elevations of cytosolic Ca(2+) that precede Bax translocation. On the other hand, agents that mobilize Ca(2+) from endoplasmic reticulum such as noradrenaline or thapsigargin, induced Bax translocation, while mitochondrial Ca(2+) release evoked by carbonyl cyanide-p-(trifluoromethoxyphenyl) hydrazone was not able to cause Bax punctation. In addition, microinjection of inositol 1,4,5- trisphosphate induced Bax translocation. Taken together, our results show that in Bax overexpressing cortical astrocytes, endoplasmic reticulum-Ca(2+) release may induce Bax transactivation and specifically control apoptosis.


Subject(s)
Astrocytes/metabolism , Calcium/metabolism , Cerebral Cortex/metabolism , Endoplasmic Reticulum/metabolism , bcl-2-Associated X Protein/metabolism , Animals , Apoptosis , Cells, Cultured , Cerebral Cortex/cytology , Flow Cytometry , Microinjections , Protein Transport , Rats
9.
Eur J Neurosci ; 32(1): 60-70, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20608968

ABSTRACT

Huntington's disease is a neurodegenerative disorder caused by an expansion of CAGs repeats and characterized by alterations in mitochondrial functions. Although changes in Ca(2+) handling have been suggested, the mechanisms involved are not completely understood. The aim of this study was to investigate the possible alterations in Ca(2+) handling capacity and the relationship with mitochondrial dysfunction evaluated by NAD(P)H fluorescence, reactive oxygen species levels, mitochondrial membrane potential (DeltaPsi(m)) measurements and respiration in whole brain slices from R6/1 mice of different ages, evaluated in situ by real-time real-space microscopy. We show that the cortex and striatum of the 9-month-old R6/1 transgenic mice present a significant sustained increase in cytosolic Ca(2+) induced by glutamate (Glu). This difference in Glu response was partially reduced in R6/1 when in the absence of extracellular Ca(2+), indicating that N-methyl-D-aspartate receptors participation in this response is more important in transgenic mice. In addition, Glu also lead to a decrease in NAD(P)H fluorescence, a loss in DeltaPsi(m) and a further increase in respiration, which may have evoked a decrease in mitochondrial Ca(2+) Ca(2+)(m) uptake capacity. Taken together, these results show that alterations in Ca(2+) homeostasis in transgenic mice are associated with a decrease in Ca(2+)(m) uptake mechanism with a diminished Ca(2+) handling ability that ultimately causes dysfunctions and worsening of the neurodegenerative and the disease processes.


Subject(s)
Brain/metabolism , Calcium Signaling/physiology , Calcium/metabolism , Glutamic Acid/metabolism , Mitochondria/metabolism , Animals , Brain/anatomy & histology , Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone/metabolism , Enzyme Inhibitors/metabolism , Homeostasis , Humans , Huntington Disease/physiopathology , Male , Membrane Potential, Mitochondrial/physiology , Mice , Mice, Transgenic , NADP/metabolism , Oxygen Consumption/physiology , Reactive Oxygen Species/metabolism , Thapsigargin/metabolism , Uncoupling Agents/metabolism
10.
Braz J Biol ; 70(2): 443-9, 2010 May.
Article in English | MEDLINE | ID: mdl-20549071

ABSTRACT

Molecular plant components have long been aimed at the angiogenesis and anti-angiogenesis pathways, and have been tested as sources for antineoplasic drugs with promising success. The present work deals with the anti-angiogenic effects of Methyl Jasmonate. Jasmonate derivatives were demonstrated to selectively damage the mitochondria of cancer cells. In vitro, 1-10 mM Methyl Jasmonate induced the cell death of the human umbilical vein endothelial cells (HUVEC) and the Murine melanoma cells (B16F10), while micromolar concentrations were ineffective. In vivo, comparable concentrations were toxic and reduced the vessel density of the Chorioallantoic Membrane of the Chicken Embryo (CAM). However, 1-10 microM concentrations produced a complex effect. There was increased capillary budding, but the new vessels were leakier and less organised than corresponding controls. It is suggested that not only direct toxicity, but also the drug effects upon angiogenesis are relevant to the antineoplasic effects of Methyl Jasmonate.


Subject(s)
Acetates/pharmacology , Angiogenesis Inhibitors/pharmacology , Antineoplastic Agents/pharmacology , Chorioallantoic Membrane/drug effects , Cyclopentanes/pharmacology , Endothelial Cells/drug effects , Oxylipins/pharmacology , Animals , Cell Line, Tumor , Chick Embryo , Chorioallantoic Membrane/blood supply , Endothelial Cells/cytology , Humans , Umbilical Veins/cytology , Umbilical Veins/drug effects
11.
J Neurosci Res ; 88(2): 438-47, 2010 Feb 01.
Article in English | MEDLINE | ID: mdl-19774672

ABSTRACT

Aging is a multifaceted process associated with various functional and structural deficits that might be evolved in degenerative diseases. It has been shown that neurodegenerative disorders are associated with alterations in Ca(2+) homeostasis. Thus, in the present work, we have investigated Ca(2+) signaling and apoptosis in aged striatum. Our results show that glutamate and NMDA evoke a greater Ca(2+) rise in striatum slices from aged animals. However, this difference is not present when glutamate is tested in the absence of external Ca(2+). Immunostaining of glutamate receptors shows that only NMDA receptors (NR1) are increased in the striatum of aged rats. Increases in mitochondrial Ca(2+) content and in the reactive oxygen species levels were also observed in aged animals, which could be associated with tissue vulnerability. In addition, a decrease in the Bcl-2 protein expression and an enhancement in apoptosis were also present in aged striatum. Together the results indicate that, in aged animals, alterations in Ca(2+) handling coupled to an increase in ROS accumulation and a decrease in the prosurvival protein Bcl-2 may contribute to apoptosis induction and cell death in rat striatum.


Subject(s)
Aging/physiology , Apoptosis/physiology , Calcium/metabolism , Corpus Striatum/physiology , Proto-Oncogene Proteins c-bcl-2/metabolism , Animals , Blotting, Western , Fluorescent Antibody Technique , Glutamic Acid/metabolism , In Situ Nick-End Labeling , In Vitro Techniques , Mitochondria/physiology , N-Methylaspartate/metabolism , Rats , Rats, Wistar , Reactive Oxygen Species/metabolism , Receptors, Glutamate/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Time Factors , bcl-2-Associated X Protein/metabolism
12.
Journal of Neuroscience Research ; 88(2): 438-447, Sept 22, 2009.
Article in English | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP, SESSP-IBACERVO | ID: biblio-1064314

ABSTRACT

Aging is a multifaceted process associated with various functional and structural deficits that might be evolved in degenerative diseases. It has been shown that neurodegenerative disorders are associated with alterations in Ca2+ homeostasis. Thus, in the present work, we have investigated Ca2+ signaling and apoptosis in aged striatum. Our results show that glutamate and NMDA evoke a greater Ca2+ rise in striatum slices from aged animals. However, this difference is not present when glutamate is tested in the absence of external Ca2+. Immunostaining of glutamate receptors shows that only NMDA receptors (NR1) are increased in the striatum of aged rats. Increases in mitochondrial Ca2+ content and in the reactive oxygen species levels were also observed in aged animals, which could be associated with tissue vulnerability. In addition, a decrease in the Bcl-2 protein expression and an enhancement in apoptosis were also present in aged striatum. Together the results indicate that, in aged animals, alterations in Ca2+ handling coupled to an increase in ROS accumulation and a decrease in the prosurvival protein Bcl-2 may contribute to apoptosis induction and cell death in rat striatum.


Subject(s)
Animals , Aged , Rats , Apoptosis , Rats/growth & development , Cellular Senescence , Calcium , Glutamic Acid
13.
Pharmacol Biochem Behav ; 91(3): 327-32, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18765248

ABSTRACT

Huntington's disease (HD) is a neurodegenerative disorder, with an age-related onset and a progressive development, characterized by choreiform movements. 3-nitropropionic acid (3NP) induces the inhibition of succinate dehydrogenase (SDH), an increase in oxidative stress and anatomic changes that are related to the pathophysiology of HD. Hence, this toxin is a useful tool to study this pathology. This study compares the effects of 3NP on the development of orofacial dyskinesia (OD) and on SDH activity in young and old mice. Treatment with 3NP (5, 10, 15 or 20 mg/kg once a day, for four days) induced OD in young mice. Old mice presented an increase in the basal level of orofacial movement that was not potentiated by any dose of 3NP. Histochemical analyses showed that old mice presented an increase in the SDH activity. Finally, 3NP induced a decrease in SDH activity at both ages. We suggest that the 3NP-induced OD in young mice is related to the inhibition of SDH activity. In parallel, an enhancement in the basal activity of SDH could be related to the absence of a further increase in the OD presented by old mice treated with 3NP.


Subject(s)
Aging/physiology , Dyskinesia, Drug-Induced/physiopathology , Nitro Compounds/pharmacology , Propionates/pharmacology , Succinate Dehydrogenase/metabolism , Animals , Brain/drug effects , Brain/enzymology , Immunohistochemistry , Male , Mice , Mice, Inbred CBA , Oxidative Stress/drug effects
14.
Neurosci Lett ; 442(2): 96-9, 2008 Sep 12.
Article in English | MEDLINE | ID: mdl-18619521

ABSTRACT

Apoptosis is a natural cell elimination process involved in a number of physiological and pathological events. This process can be regulated by members of the Bcl-2 family. Bax, a pro-apoptotic member of this family, accelerates cell death, while the pro-survival member, Bcl-x(L), can antagonize the pro-apoptotic function of Bax to promote cell survival. In the present study, we have evaluated the effect of Bcl-x(L) on Bax-induced alterations in mitochondrial respiration and calcium release. We found that in primary cultured astrocytes, recombinant Bcl-x(L) is able to antagonize Bax-induced decrease in mitochondrial respiration and increase in mitochondrial calcium release. In addition, we found that Bcl-x(L) can lower the calcium store in the endoplasmic reticulum, thus limiting potential calcium flux induced by apoptosis. This regulation of calcium flux by Bcl-x(L) may represent an important mechanism by which this protein promotes cell survival.


Subject(s)
Calcium/metabolism , Membrane Potential, Mitochondrial/drug effects , Neurons/drug effects , Neurons/ultrastructure , bcl-2-Associated X Protein/pharmacology , bcl-X Protein/pharmacology , Adenosine Triphosphate/pharmacology , Animals , Animals, Newborn , Cells, Cultured , Cerebral Cortex/cytology , Drug Interactions , Enzyme Inhibitors/pharmacology , Fura-2/metabolism , Ionomycin/pharmacology , Ionophores/pharmacology , Rats , Thapsigargin/pharmacology , Time Factors
15.
Neurosci Lett ; 438(1): 59-63, 2008 Jun 13.
Article in English | MEDLINE | ID: mdl-18468793

ABSTRACT

Huntington's disease (HD) is a hereditary dominant neurodegenerative disorder and the progression of the disease may be associated with apoptosis and altered expression of apoptotic proteins. The aim of this study was to investigate gene expression of bax and bcl-2 in tissues from R6/1 transgenic (TGN) mice of different ages (3, 6 and 9 months). The mRNA expression was investigated and related to apoptotic cells measured by TUNEL. Results showed a significant and progressive increase in bax levels in the cortex of TGN (from 10 to 33%) when compared to control (CT) (8 to 20%) mice with 3, 6 and 9-month-old. The increase in bax was correlated with the elevation in the number of apoptotic nuclei, especially in the cortex of 6 (10%) and 9 (18%)-month-old mice. Increase in bax expression might be related to an apoptotic induction which contributes to the HD progression.


Subject(s)
Apoptosis/genetics , Genetic Predisposition to Disease/genetics , Huntington Disease/genetics , Huntington Disease/metabolism , bcl-2-Associated X Protein/genetics , Animals , Cell Nucleus/pathology , Cerebral Cortex/metabolism , Cerebral Cortex/pathology , Cerebral Cortex/physiopathology , Disease Progression , Gene Expression/genetics , Huntington Disease/physiopathology , In Situ Nick-End Labeling , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Mice, Transgenic , Nerve Degeneration/genetics , Nerve Degeneration/metabolism , Nerve Degeneration/physiopathology , Neurons/metabolism , Neurons/pathology , Proto-Oncogene Proteins c-bcl-2/genetics , RNA, Messenger/metabolism , Up-Regulation/genetics
16.
Cell Death Differ ; 11(12): 1265-76, 2004 Dec.
Article in English | MEDLINE | ID: mdl-15499375

ABSTRACT

In the present study, we evaluated proapoptotic protein Bax on mitochondria and Ca2+ homeostasis in primary cultured astrocytes. We found that recombinant Bax (rBax, 10 and 100 ng/ml) induces a loss in mitochondrial membrane potential (Delta Psi m). This effect might be related to the inhibition of respiratory rates and a partial release of cytochrome c, which may change mitochondrial morphology. The loss of Delta Psi m and a selective permeabilization of mitochondrial membranes contribute to the release of Ca2+ from the mitochondria. This was inhibited by cyclosporin A (5 microM) and Ruthenium Red (1 microg/ml), indicating the involvement of mitochondrial Ca2+ transport mechanisms. Bax-induced mitochondrial Ca2+ release evokes Ca2+ waves and wave propagation between cells. Our results show that Bax induces mitochondrial alteration that affects Ca2+ homeostasis and signaling. These changes show that Ca2+ signals might be correlated with the proapoptotic activities of Bax.


Subject(s)
Apoptosis/physiology , Astrocytes/metabolism , Calcium Signaling/physiology , Calcium/metabolism , Intracellular Fluid/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Animals , Animals, Newborn , Apoptosis/drug effects , Astrocytes/drug effects , Calcium Signaling/drug effects , Cell Respiration/physiology , Cells, Cultured , Cyclosporine/pharmacology , Cytochromes c/metabolism , Intracellular Membranes/drug effects , Intracellular Membranes/metabolism , Membrane Potentials/drug effects , Membrane Potentials/physiology , Mitochondria/drug effects , Mitochondria/metabolism , Rats , Ruthenium Red/pharmacology , bcl-2-Associated X Protein
17.
J Neurochem ; 88(5): 1220-8, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15009678

ABSTRACT

Intracellular calcium homeostasis is important for cell survival. However, increase in mitochondrial calcium (Ca2+m) induces opening of permeability transition pore (PTP), mitochondrial dysfunction and apoptosis. Since alterations of intracellular Ca2+ and reactive oxygen species (ROS) generation are involved in cell death, they might be involved in neurodegenerative processes such as Huntington's disease (HD). HD is characterized by the inhibition of complex II of respiratory chain and increase in ROS production. In this report, we studied the correlation between the inhibitor of the complex II, 3-nitropropionic acid (3NP), Ca2+ metabolism, apoptosis and behavioural alterations. We showed that 3NP (1 mm) is able to release Ca2+m, as neither Thapsigargin (TAP, 2 microm) nor free-calcium medium affected its effect. PTP inhibitors and antioxidants inhibited this process, suggesting an increase in ROS generation and PTP opening. In addition, 3NP (0.1 mm) also induces apoptotic cell death. Behavioural changes in animals treated with 3NP (20 mg/kg/day for 4 days) were also attenuated by pre- and co-treatment with vitamin E (VE, 20 mg/kg/day). Taken together, our results show that complex II inhibition could involve Ca2+m release, oxidative stress and cell death that may precede motor alterations in neurodegenerative processes such as HD.


Subject(s)
Apoptosis , Astrocytes/metabolism , Calcium/metabolism , Mitochondria/metabolism , Neurodegenerative Diseases/metabolism , Oxidative Stress , Animals , Antioxidants/pharmacology , Apoptosis/drug effects , Astrocytes/drug effects , Astrocytes/pathology , Behavior, Animal/drug effects , Cell Survival/drug effects , Cells, Cultured , Crosses, Genetic , Disease Models, Animal , Electron Transport Complex II/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Fluorescent Dyes , Male , Mice , Mitochondria/drug effects , Neurodegenerative Diseases/chemically induced , Neurodegenerative Diseases/pathology , Nitro Compounds , Oxidative Stress/drug effects , Propionates , Uncoupling Agents/pharmacology , Vitamin E/pharmacology
18.
Braz J Med Biol Res ; 36(2): 183-90, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12563519

ABSTRACT

Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injury and programmed cell death through the regulation of a number of Ca2+-dependent enzymes such as phospholipases, proteases, and nucleases. Mitochondria along with the endoplasmic reticulum play pivotal roles in regulating intracellular Ca2+ content. Mitochondria are endowed with multiple Ca2+ transport mechanisms by which they take up and release Ca2+ across their inner membrane. During cellular Ca2+ overload, mitochondria take up cytosolic Ca2+, which in turn induces opening of permeability transition pores and disrupts the mitochondrial membrane potential (deltapsim). The collapse of deltapsim along with the release of cytochrome c from mitochondria is followed by the activation of caspases, nuclear fragmentation and cell death. Members of the Bcl-2 family are a group of proteins that play important roles in apoptosis regulation. Members of this family appear to differentially regulate intracellular Ca2+ level. Translocation of Bax, an apoptotic signaling protein, from the cytosol to the mitochondrial membrane is another step in this apoptosis signaling pathway.


Subject(s)
Apoptosis/physiology , Calcium Signaling/physiology , Lymphokines/physiology , Mitochondria/physiology , Proto-Oncogene Proteins c-bcl-2/physiology , Animals , Proto-Oncogene Proteins/physiology , bcl-2-Associated X Protein
19.
Braz. j. med. biol. res ; 36(2): 183-190, Feb. 2003. ilus
Article in English | LILACS | ID: lil-326426

ABSTRACT

Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injury and programmed cell death through the regulation of a number of Ca2+-dependent enzymes such as phospholipases, proteases, and nucleases. Mitochondria along with the endoplasmic reticulum play pivotal roles in regulating intracellular Ca2+ content. Mitochondria are endowed with multiple Ca2+ transport mechanisms by which they take up and release Ca2+ across their inner membrane. During cellular Ca2+ overload, mitochondria take up cytosolic Ca2+, which in turn induces opening of permeability transition pores and disrupts the mitochondrial membrane potential (Dym). The collapse of Dym along with the release of cytochrome c from mitochondria is followed by the activation of caspases, nuclear fragmentation and cell death. Members of the Bcl-2 family are a group of proteins that play important roles in apoptosis regulation. Members of this family appear to differentially regulate intracellular Ca2+ level. Translocation of Bax, an apoptotic signaling protein, from the cytosol to the mitochondrial membrane is another step in this apoptosis signaling pathway


Subject(s)
Animals , Apoptosis , Calcium Signaling , Lymphokines , Mitochondria , Proto-Oncogene Proteins c-bcl-2 , Proto-Oncogene Proteins
20.
Cell Death Differ ; 8(9): 909-20, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11526446

ABSTRACT

Bax, a pro-apoptotic member of the Bcl-2 family, is a cytosolic protein that inserts into mitochondrial membranes upon induction of cell death. Using the green fluorescent protein fused to Bax (GFP-Bax) to quantitate mitochondrial binding in living cells we have investigated the cause of Bax association with mitochondria and the time course relative to endogenous and induced changes in mitochondrial membrane potential (DeltaPsi(m)). We have found that staurosporine (STS) induces a loss in DeltaPsi(m) before GFP-Bax translocation can be measured. The onset of the DeltaPsi(m) loss is followed by a rapid and complete collapse of DeltaPsi(m) which is followed by Bax association with mitochondria. The mitochondria uncoupler FCCP, in the presence of the F(1)-F(0) ATPase inhibitor oligomycin, can trigger Bax translocation to mitochondria suggesting that when ATP levels are maintained a collapse of DeltaPsi(m) induces Bax translocation. Neither FCCP nor oligomycin alone alters Bax location. Bax association with mitochondria is also triggered by inhibitors of the electron transport chain, antimycin and rotenone, compounds that collapse DeltaPsi(m) without inducing rapid ATP hydrolysis that typically occurs with uncouplers such as FCCP. Taken together, our results suggest that alterations in mitochondrial energization associated with apoptosis can initiate Bax docking to mitochondria.


Subject(s)
Intracellular Membranes/metabolism , Membrane Potentials , Mitochondria/metabolism , Proto-Oncogene Proteins c-bcl-2 , Proto-Oncogene Proteins/metabolism , Adenosine Triphosphatases/antagonists & inhibitors , Adenosine Triphosphatases/metabolism , Adenosine Triphosphate/metabolism , Animals , Apoptosis/drug effects , COS Cells , Calcium/metabolism , Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone/pharmacology , Chelating Agents/pharmacology , Electrochemistry , Electron Transport/drug effects , Intracellular Membranes/drug effects , Membrane Potentials/drug effects , Microscopy, Confocal , Mitochondria/drug effects , Oligomycins/pharmacology , Protein Binding , Protein Transport/drug effects , Staurosporine/pharmacology , bcl-2-Associated X Protein
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