Effect of chronic sleep restriction and aging on calcium signaling and apoptosis in the hippocampus of young and aged animals

Aging leads to progressive deterioration of physiological function and diminished responses to environmental stress. Organic and functional alterations are frequently observed in elderly subjects. Although chronic sleep loss is observed during senescence, little is known about the impact of insufficient sleep on cellular function in aging neurons. Disruption of neuronal calcium (Ca2+) signaling is related to impaired neuronal function and cell death. It has been hypothesized that sleep deprivation may compromise neuronal stability and induce cell death in young neurons; however, it is necessary to evaluate the impact of aging on this process. Therefore, the aim of this study was to evaluate the effects of chronic sleep restriction (CSR) on Ca2+ signaling and cell death in the hippocampus of young and aged animals. We found that glutamate and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP) induced a greater elevation in cytosolic Ca2+ ([Ca2+](c)) in hippocampal slices from aged rats subjected to CSR compared to age-matched controls. Interestingly, aged-matched controls showed a reduced Ca2+ response to glutamate and FCCP, relative to both CSR and control young animals. Apoptotic nuclei were observed in aged rats from both treatment groups; however, the profile of apoptotic nuclei in aged CSR rats was highly variable. Bax and Bc1-2 protein expression did not change with aging in the CSR groups. Our study indicates that aging promotes changes in Ca2+ signaling, which may also be affected by CSR. These age-dependent changes in Ca2+ signaling may increase cellular vulnerability during CSR and contribute to Ca2+ signaling dysregulation, which may ultimately induce cell death. (c) 2012 Elsevier Inc. All rights reserved.Associacao Fundo de Incentivo a Pesquisa (AFIP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CEPIDConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo UNIFESP, Dept Psicobiol, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Farmacol, BR-04044020 São Paulo, BrazilUN1FESP, Ctr Microscopia Eletron, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Psicobiol, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Farmacol, BR-04044020 São Paulo, BrazilFAPESP: 08/50424-3CEPID: 98/14303-3Web of Scienc

Mitochondrial involvement in carbachol-induced intracellular Ca2+ mobilization and contraction in rat gastric smooth muscle

Aims: Mitochondria are important modulators of Ca2+ homeostasis. However, it is not clear if they modulate and participate in smooth muscle signaling and contraction. the aim of the present work was to investigate the role of mitochondria in Ca2+ transients and contraction induced by metabotropic muscarinic receptor activation in rat gastric smooth muscle.Main methods: Carbachol (CC11)-induced contraction was investigated in the absence or presence of increasing concentration of mitochondrial protonophore, carbonyl cyanide p-(trifluoro-methoxy)phenyl-hydrazone (FCCP), in gastric fundus strips. Ca2+ and mitochondrial membrane potential (Delta Psi m) measurements were performed in primarily cultured gastric smooth muscle cells loaded with FURA-2 or TMRE dyes.Key findings: Results show that CCh (1 mu M)-induced contraction was inhibited by FCCP in a concentration-dependent manner. in cultured smooth muscle cells CCh (1 mu M) caused a cytosolic Ca2+ rise. Preincubation with FCCP strongly inhibited CCh-evoked Ca2+ transients indicating that mitochondria shape intracellular Ca2+ Signals. CCh induced elevations of Delta Psi m in 60% of the individual mitochondrion analyzed.Significance: Taken together our results indicate that CCh induces release of Ca2+ from intracellular stores, which may be modulated by mitochondria. Thus, mitochondria participate of the intracellular Ca2+ homeostasis in muscarinic contraction in gastric fundus smooth muscle. (C) 2011 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fed Univ São Paulo UNIFESP EPM, Dept Pharmacol, Paulista Sch Med, São Paulo, BrazilFed Univ Pernambuco UFPE, Dept Pharmaceut Sci, Recife, PE, BrazilFed Univ São Paulo UNIFESP EPM, Dept Pharmacol, Paulista Sch Med, São Paulo, BrazilWeb of Scienc

Autophagy and intermittent fasting: the connection for cancer therapy?

Cancer is a leading cause of death worldwide, and its incidence is continually increasing. Although anticancer therapy has improved significantly, it still has limited efficacy for tumor eradication and is highly toxic to healthy cells. Thus, novel therapeutic strategies to improve chemotherapy, radiotherapy and targeted therapy are an important goal in cancer research. Macroautophagy (herein referred to as autophagy) is a conserved lysosomal degradation pathway for the intracellular recycling of macromolecules and clearance of damaged organelles and misfolded proteins to ensure cellular homeostasis. Dysfunctional autophagy contributes to many diseases, including cancer. Autophagy can suppress or promote tumors depending on the developmental stage and tumor type, and modulating autophagy for cancer treatment is an interesting therapeutic approach currently under intense investigation. Nutritional restriction is a promising protocol to modulate autophagy and enhance the efficacy of anticancer therapies while protecting normal cells. Here, the description and role of autophagy in tumorigenesis will be summarized. Moreover, the possibility of using fasting as an adjuvant therapy for cancer treatment, as well as the molecular mechanisms underlying this approach, will be presented

Effective Synergy of Sorafenib and Nutrient Shortage in Inducing Melanoma Cell Death through Energy Stress

Skin melanoma is one of the most aggressive and difficult-to-treat human malignancies, characterized by poor survival rates, thus requiring urgent novel therapeutic approaches. Although metabolic reprogramming has represented so far, a cancer hallmark, accumulating data indicate a high plasticity of cancer cells in modulating cellular metabolism to adapt to a heterogeneous and continuously changing microenvironment, suggesting a novel therapeutic approach for dietary manipulation in cancer therapy. To this aim, we exposed melanoma cells to combined nutrient-restriction/sorafenib. Results indicate that cell death was efficiently induced, with apoptosis representing the prominent feature. In contrast, autophagy was blocked in the final stage by this treatment, similarly to chloroquine, which also enhanced melanoma cell sensitization to combined treatment. Energy stress was evidenced by associated treatment with mitochondrial dysfunction and glycolysis impairment, suggesting metabolic stress determining melanoma cell death. A reduction of tumor growth after cycles of intermittent fasting together with sorafenib treatment was also observed in vivo, reinforcing that the nutrient shortage can potentiate anti-melanoma therapy. Our findings showed that the restriction of nutrients by intermittent fasting potentiates the effects of sorafenib due to the modulation of cellular metabolism, suggesting that it is possible to harness the energy of cancer cells for the treatment of melanoma