A comprehensive systematic review of CSF proteins and peptides that define Alzheimer's disease.

BACKGROUND: During the last two decades, over 100 proteomics studies have identified a variety of potential biomarkers in CSF of Alzheimer's (AD) patients. Although several reviews have proposed specific biomarkers, to date, the statistical relevance of these proteins has not been investigated and no peptidomic analyses have been generated on the basis of specific up- or down- regulation. Herein, we perform an analysis of all unbiased explorative proteomics studies of CSF biomarkers in AD to critically evaluate whether proteins and peptides identified in each study are consistent in distribution; direction change; and significance, which would strengthen their potential use in studies of AD pathology and progression. METHODS: We generated a database containing all CSF proteins whose levels are known to be significantly altered in human AD from 47 independent, validated, proteomics studies. Using this database, which contains 2022 AD and 2562 control human samples, we examined whether each protein is consistently present on the basis of reliable statistical studies; and if so, whether it is over- or under-represented in AD. Additionally, we performed a direct analysis of available mass spectrometric data of these proteins to generate an AD CSF peptide database with 3221 peptides for further analysis. RESULTS: Of the 162 proteins that were identified in 2 or more studies, we investigated their enrichment or depletion in AD CSF. This allowed us to identify 23 proteins which were increased and 50 proteins which were decreased in AD, some of which have never been revealed as consistent AD biomarkers (i.e. SPRC or MUC18). Regarding the analysis of the tryptic peptide database, we identified 87 peptides corresponding to 13 proteins as the most highly consistently altered peptides in AD. Analysis of tryptic peptide fingerprinting revealed specific peptides encoded by CH3L1, VGF, SCG2, PCSK1N, FBLN3 and APOC2 with the highest probability of detection in AD. CONCLUSIONS: Our study reveals a panel of 27 proteins and 21 peptides highly altered in AD with consistent statistical significance; this panel constitutes a potent tool for the classification and diagnosis of AD.

Sex-dependent co-occurrence of hypoxia and ß-amyloid plaques in hippocampus and entorhinal cortex is reversed by long-term treatment with ubiquinol and ascorbic acid in the 3 × Tg-AD mouse model of Alzheimer's disease.

Structural and functional abnormalities in the cerebral microvasculature have been observed in Alzheimer's disease (AD) patients and animal models. One cause of hypoperfusion is the thickening of the cerebrovascular basement membrane (CVBM) due to increased collagen-IV deposition around capillaries. This study investigated whether these and other alterations in the cerebrovascular system associated with AD can be prevented by long-term dietary supplementation with the antioxidant ubiquinol (Ub) stabilized with Kaneka QH P30 powder containing ascorbic acid (ASC) in a mouse model of advanced AD (3 × Tg-AD mice, 12 months old). Animals were treated from prodromal stages of disease (3 months of age) with standard chow without or with Ub + ASC or ASC-containing vehicle and compared to wild-type (WT) mice. The number of ß-amyloid (Aß) plaques in the hippocampus and entorhinal cortex was higher in female than in male 3 × Tg-AD mice. Extensive regions of hypoxia were characterized by a higher plaque burden in females only. This was abolished by Ub + ASC and, to a lesser extent, by ASC treatment. Irrespective of Aß burden, increased collagen-IV deposition in the CVBM was observed in both male and female 3 × Tg-AD mice relative to WT animals; this was also abrogated in Ub + ASC- and ASC-treated mice. The chronic inflammation in the hippocampus and oxidative stress in peripheral leukocytes of 3 × Tg-AD mice were likewise reversed by antioxidant treatment. These results provide strong evidence that long-term antioxidant treatment can mitigate plasma oxidative stress, amyloid burden, and hypoxia in the AD brain parenchyma.

Environmental and health risk implications of unregulated emissions from advanced biofuels in a Euro 6 engine.

The use of conventional and advanced biofuels is part of the efforts to reduce greenhouse gases and harmful exhaust gaseous emissions. This study investigates the unregulated emissions in gas and particles from a Euro 6b diesel engine, operated with four unconventional and advanced biofuels (two hydrogenated terpenic biofuels, a polyoxymethylene dimethyl ether, and a glycerol-derived biofuel), blended with diesel fuel and pure hydrotreated vegetable oil as base biofuel. The engine was operated following WLTC starting from cold-engine conditions. Gas phase samples were collected at each phase of the driving cycle and particulate matter (PM) samples were collected from a dilution tunnel at the end of the driving cycle. A total of 16 PAH and 13 carbonyls were analyzed. In addition, the apoptotic index induced by gas and particle emissions was determined. In the gaseous phase, the total PAH and carbonyl emission factors were higher at the low-speed phase for all fuels. Gas-phase PAH emission factors exceeded particle-bound PAH. Carbonyl emission factors ranged from 0.12 ± 0.012 to 25.3 ± 4.2 mg/km, markedly exceeding gaseous PAH emissions, which ranged from 20.7 ± 1.5 to 51.7 ± 8.9 µg/km. Diesel fuel exhibited the highest carbonyl emissions and its blend with 20% of hydrogenated turpentine exhibited the highest PAH emissions at the end of the WLTC, both due to high emissions at the low-speed phase. Although particle-bound PAH comprise only a small fraction of total PAH emissions, both phases (gas and particles) contributed approximately equal to the toxicity associated with carcinogenic PAH. The apoptotic cells percentage increased in a dose-dependent manner and was significantly higher in cells exposed to gas phase-derived samples. The apoptotic index induced by particulate matter samples did not show a concentration-response effect for any of the fuels.

CoQ10 reduces glioblastoma growth and infiltration through proteome remodeling and inhibition of angiogenesis and inflammation.

PURPOSE: Most monotherapies available against glioblastoma multiforme (GBM) target individual hallmarks of this aggressive brain tumor with minimal success. In this article, we propose a therapeutic strategy using coenzyme Q10 (CoQ10) as a pleiotropic factor that crosses the blood-brain barrier and accumulates in cell membranes acting as an antioxidant, and in mitochondrial membranes as a regulator of cell bioenergetics and gene expression. METHODS: Xenografts of U251 cells in nu/nu mice were used to assay tumor growth, hypoxia, angiogenesis, and inflammation. An orthotopic model was used to explore microglial infiltration, tumor growth, and invasion into the brain parenchyma. Cell proliferation, migration, invasion, proteome remodeling, and secretome were assayed in vitro. Conditioned media were used to assay angiogenesis, monocyte chemoattraction, and differentiation into macrophages in vitro. RESULTS: CoQ10 treatment decreased tumor volume in xenografts and orthotopic models, although its effect on tumor cell proliferation was not direct. Tumors from mice treated with CoQ10 were less hypoxic and vascularized, having less infiltration from inflammatory cells. Treatment-induced downregulation of HIF-1α and NF-kB led to a complete remodeling of the tumor cells proteome and secretome, impacting angiogenesis, monocyte infiltration, and their differentiation into macrophages. Besides, tumor cell migration and invasion were drastically restricted by mechanisms involving modulation of the actin cytoskeleton and downregulation of matrix metalloproteases (MMPs). CONCLUSIONS: CoQ10 has a pleiotropic effect on GBM growth, targeting several hallmarks simultaneously. Thus, its integration into current treatments of this fatal disease should be considered.

Biological Significance of the Protein Changes Occurring in the Cerebrospinal Fluid of Alzheimer's Disease Patients: Getting Clues from Proteomic Studies.

The fact that cerebrospinal fluid (CSF) deeply irrigates the brain together with the relative simplicity of sample extraction from patients make this biological fluid the best target for biomarker discovery in neurodegenerative diseases. During the last decade, biomarker discovery has been especially fruitful for the identification new proteins that appear in the CSF of Alzheimer's disease (AD) patients together with amyloid-ß (Aß42), total tau (T-tau), and phosphorylated tau (P-tau). Thus, several proteins have been already stablished as important biomarkers, due to an increase (i.e., CHI3L1) or a decrease (i.e., VGF) in AD patients' CSF. Notwithstanding this, only a deep analysis of a database generated with all the changes observed in CSF across multiple proteomic studies, and especially those using state-of-the-art methodologies, may expose those components or metabolic pathways disrupted at different levels in AD. Deep comparative analysis of all the up- and down-regulated proteins across these studies revealed that 66% of the most consistent protein changes in CSF correspond to intracellular proteins. Interestingly, processes such as those associated to glucose metabolism or RXR signaling appeared inversely represented in CSF from AD patients in a significant manner. Herein, we discuss whether certain cellular processes constitute accurate indicators of AD progression by examining CSF. Furthermore, we uncover new CSF AD markers, such as ITAM, PTPRZ or CXL16, identified by this study.

Ubiquinol Supplementation Improves Gender-Dependent Cerebral Vasoreactivity and Ameliorates Chronic Inflammation and Endothelial Dysfunction in Patients with Mild Cognitive Impairment.

Ubiquinol can protect endothelial cells from multiple mechanisms that cause endothelial damage and vascular dysfunction, thus contributing to dementia. A total of 69 participants diagnosed with mild cognitive impairment (MCI) received either 200 mg/day ubiquinol (Ub) or placebo for 1 year. Cognitive assessment of patients was performed at baseline and after 1 year of follow-up. Patients' cerebral vasoreactivity was examined using transcranial Doppler sonography, and levels of Ub and lipopolysaccharide (LPS) in plasma samples were quantified. Cell viability and necrotic cell death were determined using the microvascular endothelial cell line bEnd3. Coenzyme Q10 (CoQ) levels increased in patients supplemented for 1 year with ubiquinol versus baseline and the placebo group, although higher levels were observed in male patients. The higher cCoQ concentration in male patients improved cerebral vasoreactivity CRV and reduced inflammation, although the effect of Ub supplementation on neurological improvement was negligible in this study. Furthermore, plasma from Ub-supplemented patients improved the viability of endothelial cells, although only in T2DM and hypertensive patients. This suggests that ubiquinol supplementation could be recommended to reach a concentration of 5 µg/mL in plasma in MCI patients as a complement to conventional treatment.

SIRT1 and SIRT2 Activity Control in Neurodegenerative Diseases.

Sirtuins are NAD+ dependent histone deacetylases (HDAC) that play a pivotal role in neuroprotection and cellular senescence. SIRT1-7 are different homologs from sirtuins. They play a prominent role in many aspects of physiology and regulate crucial proteins. Modulation of sirtuins can thus be utilized as a therapeutic target for metabolic disorders. Neurological diseases have distinct clinical manifestations but are mainly age-associated and due to loss of protein homeostasis. Sirtuins mediate several life extension pathways and brain functions that may allow therapeutic intervention for age-related diseases. There is compelling evidence to support the fact that SIRT1 and SIRT2 are shuttled between the nucleus and cytoplasm and perform context-dependent functions in neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). In this review, we highlight the regulation of SIRT1 and SIRT2 in various neurological diseases. This study explores the various modulators that regulate the activity of SIRT1 and SIRT2, which may further assist in the treatment of neurodegenerative disease. Moreover, we analyze the structure and function of various small molecules that have potential significance in modulating sirtuins, as well as the technologies that advance the targeted therapy of neurodegenerative disease.

Human amyloid-ß enriched extracts: evaluation of in vitro and in vivo internalization and molecular characterization.

BACKGROUND: Intracerebral inoculation of extracts from post-mortem human Alzheimer's disease brains into mice produces a prion-like spreading effect of amyloid-ß. The differences observed between these extracts and the synthetic peptide, in terms of amyloid-ß internalization and seed and cell-to-cell transmission of cytosolic protein aggregates, suggest that brain extracts contain key contributors that enhance the prion-like effect of amyloid-ß. Nevertheless, these potential partners are still unknown due to the complexity of whole brain extracts. METHODS: Herein, we established a method based on sequential detergent solubilization of post-mortem samples of human brains affected by Alzheimer's disease that strongly enrich amyloid-ß aggregates by eliminating 92% of the remaining proteins. Internalization of Aß1-42 from the enriched AD extracts was evaluated in vitro, and internalization of fluorescent-labeled AD extracts was also investigated in vivo. Furthermore, we carried out a molecular characterization of the Aß-enriched fraction using label-free proteomics, studying the distribution of representative components in the amygdala and the olfactory cortex of additional human AD brain samples by immunohistochemistry. RESULTS: Aß1-42 from the enriched AD extracts are internalized into endothelial cells in vitro after 48 h. Furthermore, accumulation of fluorescent-labeled Aß-enriched extracts into mouse microglia was observed in vivo after 4 months of intracerebral inoculation. Label-free proteomics (FDR < 0.01) characterization of the amyloid-ß-enriched fraction from different post-mortem samples allowed for the identification of more than 130 proteins, several of which were significantly overrepresented (i.e., ANXA5 and HIST1H2BK; p < 0.05) and underrepresented (i.e., COL6A or FN1; p < 0.05) in the samples with Alzheimer's disease. We were also able to identify proteins exclusively observed in Alzheimer's disease (i.e., RNF213) or only detected in samples not affected by the disease (i.e., CNTN1) after the enrichment process. Immunohistochemistry against these proteins in additional tissues revealed their particular distribution in the amygdala and the olfactory cortex in relation to the amyloid-ß plaque. CONCLUSIONS: Identification and characterization of the unique features of these extracts, in terms of amyloid-ß enrichment, identification of the components, in vitro and in vivo cell internalization, and tissue distribution, constitute the best initial tool to further investigate the seeding and transmissibility proposed in the prion-like hypothesis of Alzheimer's disease.

Urotensin II and urotensin II-related peptide activate somatostatin receptor subtypes 2 and 5.

The UII and urotensin II-related peptide (URP) genes belong to the same superfamily as the somatostatin gene. It has been previously shown that somatostatin activates the UII-receptor (UTR). In contrast, the possible interaction between UII and URP and somatostatin receptors has remained scarcely analyzed. Herein, we have investigated the effects of UII and URP on cell proliferation and free cytosolic Ca2+ concentration ([Ca2+]i) in CHO-K1 cells stably expressing the porcine somatostatin receptor subtypes sst2 and sst5. Results show that both UII and URP induce stimulation of cell proliferation mediated by sst2 receptors and UII provokes inhibition of cell proliferation mediated by sst5 receptors. UII and URP also provoked an increase of [Ca2+]i in both sst2- and sst5-transfected cells. Together, our present data demonstrate that UII and URP directly activate sst2 and sst5 and thus mimic the effect of somatostatin on its cognate receptors.

Regulation of the oxidative balance with coenzyme Q10 sensitizes human glioblastoma cells to radiation and temozolomide.

OBJECTIVES: To investigate how the modulation of the oxidative balance affects cytotoxic therapies in glioblastoma, in vitro. MATERIAL AND METHODS: Human glioblastoma U251 and T98 cells and normal astrocytes C8D1A were loaded with coenzyme Q10 (CoQ). Mitochondrial superoxide ion (O2-) and H2O2 were measured by fluorescence microscopy. OXPHOS performance was assessed in U251 cells with an oxytherm Clark-type electrode. Radio- and chemotherapy cytotoxicity was assessed by immunostaining of γH2AX (24 h), annexin V and nuclei morphology, at short (72 h) and long (15 d) time. Hif-1α, SOD1, SOD2 and NQO1 were determined by immunolabeling. Catalase activity was measured by classic enzymatic assay. Glutathione levels and total antioxidant capacity were quantified using commercial kits. RESULTS: CoQ did not affect oxygen consumption but reduced the level of O2- and H2O2 while shifted to a pro-oxidant cell status mainly due to a decrease in catalase activity and SOD2 level. Hif-1α was dampened, echoed by a decrease lactate and several key metabolites involved in glutathione synthesis. CoQ-treated cells were twofold more sensitive than control to radiation-induced DNA damage and apoptosis in short and long-term clonogenic assays, potentiating TMZ-induced cytotoxicity, without affecting non-transformed astrocytes. CONCLUSIONS: CoQ acts as sensitizer for cytotoxic therapies, disarming GBM cells, but not normal astrocytes, against further pro-oxidant injuries, being potentially useful in clinical practice for this fatal pathology.

Cellular density and cell type are the key factors in growth inhibition induced by 2,5bis [1-aziridinyl]-1,4 benzoquinone (DZQ).

BACKGROUND: Cell density regulates the expression of various antioxidant enzymes in cell culture. The aim of this study was to study the effect of 2,5 bis-[1-aziridinyl]-1,4 benzoquinone (DZQ), an antitumor quinone bioactivated by NQO1, on HeLa and HepG2 cells cultured at various cell densities. MATERIALS AND METHODS: Quinone toxicity was determined by a colorimetric growth inhibition assay. NQO1 and catalase activities were measured spectrophotometrically in soluble fractions, and NQO1 polypeptide was quantified by immunostaining with a commercial polyclonal antiserum. RESULTS: As reported previously, NQO1 activity was much higher in confluent HeLa cells than in sparse cells. However, HepG2 cultures showed an opposite pattern in the regulation of this antioxidant enzyme, sparse cell cultures showing higher NQO1 activity similar to that found in confluent HeLa cells. The expression pattern of catalase activity was similar to that of NQO1 in HeLa cells, but this activity was constant and cell density-independent in HepG2. The growth inhibition effect of DZQ, correlated with NQO1 activity within a given cell type, but HepG2 was always much more sensitive to DZQ than HeLa cells, even under conditions where NQO1 activity was high in HeLa but low in HepG2. CONCLUSION: These results suggest that NQO1 activity is a major factor for DZQ bioactivation, but this enzyme is not likely the sole factor involved in the growth inhibition mediated by DZQ. Since part of the cytotoxic effect of DZQ is mediated by H2O2, other antioxidant enzymes, mainly catalase, could modulate the different growth inhibition found between HeLa and HepG2 cells. In confluent HeLa cells, the higher activity of NQO1 coincides with an increment of catalase activity, thus, reducing the oxidative stress produced by the H2O2 formed.

Enhanced anti-oxidant protection of liver membranes in long-lived rats fed on a coenzyme Q10-supplemented diet.

Coenzyme Q10 supplementation increases life-span of rats fed on a diet enriched with polyunsaturated fatty acids (Quiles, J.L., Ochoa, J.J., Huertas, J.R., Mataix, J., 2004b. Coenzyme Q supplementation protects from age-related DNA double-strand breaks and increased lifespan in rats fed on a PUFA-rich diet. Exp. Gerontol. 39, 189-194). Our study was set as a first attempt to establish a mechanistic link between life span extension and CoQ10 supplementation. When rats were fed on a PUFAn-6 plus CoQ10 diet, levels of CoQ10 were increased in plasma membrane at every time point compared to control rats fed on a PUFAn-6-alone diet. Ratios of CoQ9 to CoQ10 were significantly lower at every time point in both liver plasma membranes and homogenates of CoQ10-supplemented animals. CoQ10 supplementation did not affect cytosolic NAD(P)H:quinone oxidoreductase 1 (NQO1), which increased significantly with aging, but plasma membrane-bound NQO1 decreased significantly in the CoQ10-supplemented group at 12 months, when maximal incorporation of exogenous CoQ10 was observed. Neither aging nor the diet affected NADH-cytochrome b5 reductase levels. Glutathione-dependent anti-oxidant activities such as cytosolic glutathione-S-transferase (GST) and microsomal Se-independent glutathione peroxidase decreased with aging and supplementation with CoQ10 attenuated this decay. 2,2' Azobis amidinopropane (AAPH)-induced oxidation of membranes was significantly higher in aged rats, and supplementation with CoQ10 also inhibited this increase. Consistent with higher CoQ10 levels and enhanced anti-oxidant protection, plasma membrane Mg2+-dependent neutral sphingomyelinase was inhibited by dietary CoQ10 in aged rats. Our results support the involvement of thiol-dependent mechanisms in the potentiation of the anti-oxidant capacity of membranes in CoQ10-supplemented rats, further supporting the potentially beneficial anti-oxidative role of dietary CoQ10 during aging. The possibility that a decreased CoQ9/CoQ10 ratio in animals fed on the PUFAn-6-rich plus CoQ10 diet could also influence longevity is also discussed.

Combined therapies of antithrombotics and antioxidants delay in silico brain tumour progression.

Glioblastoma multiforme (GBM), the most frequent type of primary brain tumour, is a rapidly evolving and spatially heterogeneous high-grade astrocytoma that presents areas of necrosis, hypercellularity and microvascular hyperplasia. The aberrant vasculature leads to hypoxic areas and results in an increase in oxidative stress, selecting for more invasive tumour cell phenotypes. In our study, we assay in silico different therapeutic approaches which combine antithrombotics (ATs), antioxidants and standard radiotherapy (RT). To do so, we have developed a biocomputational model of GBM that incorporates the spatio-temporal interplay among two glioma cell phenotypes corresponding to oxygenated and hypoxic cells, a necrotic core and the local vasculature whose response evolves with tumour progression. Our numerical simulations predict that suitable combinations of ATs and antioxidants may diminish, in a synergistic way, oxidative stress and the subsequent hypoxic response. This novel therapeutical strategy, with potentially low or no toxicity, might reduce tumour invasion and further sensitize GBM to conventional RT or other cytotoxic agents, hopefully increasing median patient overall survival time.

Coenzyme Q10 protects human endothelial cells from ß-amyloid uptake and oxidative stress-induced injury.

Neuropathological symptoms of Alzheimer's disease appear in advances stages, once neuronal damage arises. Nevertheless, recent studies demonstrate that in early asymptomatic stages, ß-amyloid peptide damages the cerebral microvasculature through mechanisms that involve an increase in reactive oxygen species and calcium, which induces necrosis and apoptosis of endothelial cells, leading to cerebrovascular dysfunction. The goal of our work is to study the potential preventive effect of the lipophilic antioxidant coenzyme Q (CoQ) against ß-amyloid-induced damage on human endothelial cells. We analyzed the protective effect of CoQ against Aß-induced injury in human umbilical vein endothelial cells (HUVECs) using fluorescence and confocal microscopy, biochemical techniques and RMN-based metabolomics. Our results show that CoQ pretreatment of HUVECs delayed Aß incorporation into the plasma membrane and mitochondria. Moreover, CoQ reduced the influx of extracellular Ca(2+), and Ca(2+) release from mitochondria due to opening the mitochondrial transition pore after ß-amyloid administration, in addition to decreasing O2(.-) and H2O2 levels. Pretreatment with CoQ also prevented ß-amyloid-induced HUVECs necrosis and apoptosis, restored their ability to proliferate, migrate and form tube-like structures in vitro, which is mirrored by a restoration of the cell metabolic profile to control levels. CoQ protected endothelial cells from Aß-induced injury at physiological concentrations in human plasma after oral CoQ supplementation and thus could be a promising molecule to protect endothelial cells against amyloid angiopathy.

Sirtuin activators and inhibitors.

Sirtuins 1-7 (SIRT1-7) belong to the third class of deacetylase enzymes, which are dependent on NAD(+) for activity. Sirtuins activity is linked to gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection, and healthy aging. Because sirtuins modulation could have beneficial effects on human diseases there is a growing interest in the discovery of small molecules modifying their activities. We review here those compounds known to activate or inhibit sirtuins, discussing the data that support the use of sirtuin-based therapies. Almost all sirtuin activators have been described only for SIRT1. Resveratrol is a natural compound which activates SIRT1, and may help in the treatment or prevention of obesity, and in preventing tumorigenesis and the aging-related decline in heart function and neuronal loss. Due to its poor bioavailability, reformulated versions of resveratrol with improved bioavailability have been developed (resVida, Longevinex(®) , SRT501). Molecules that are structurally unrelated to resveratrol (SRT1720, SRT2104, SRT2379, among others) have been also developed to stimulate sirtuin activities more potently than resveratrol. Sirtuin inhibitors with a wide range of core structures have been identified for SIRT1, SIRT2, SIRT3 and SIRT5 (splitomicin, sirtinol, AGK2, cambinol, suramin, tenovin, salermide, among others). SIRT1 inhibition has been proposed in the treatment of cancer, immunodeficiency virus infections, Fragile X mental retardation syndrome and for preventing or treating parasitic diseases, whereas SIRT2 inhibitors might be useful for the treatment of cancer and neurodegenerative diseases.

A patent review of sirtuin activators: an update.

INTRODUCTION: Reversible acetylation is a key post-translational modification of target proteins. Sirtuin deacetylases represent the homolog of the yeast silent information regulator (SIR2). Although seven sirtuins have been found in mammals, all sirtuin activators described to date act through SIRT1. AREAS COVERED: Areas covered in this paper include a review of the patent literature associated with SIRT1 activators, with a focus on therapeutic applications, primarily related to the use of pharmaceuticals and nutraceuticals containing resveratrol (RSV), and the development of second-generation activators unrelated to RSV. Also discussed is the current controversy over whether or not these molecules are actual SIRT1 activators. EXPERT OPINION: Developing effective strategies to protect against diet-induced metabolic imbalance is necessary to fight against current obesity rates. The hypothalamus is a candidate for developing drugs that suppress SIRT1 degradation, as a strategy for treating metabolic syndrome. Deciphering the basic mechanism of activators is essential to develop effective strategies to alter sirtuin activity. This is true regardless of the apparent controversy of whether in vitro activation of SIRT1 is direct or not, depending on the experimental design, and whether sirtuins may play a major role in longevity. The numerous studies on their positive effects against age-related diseases, obesity and other metabolic disorders are still valid, promising to positively influence the development of treatments to improve human health.

Genetic deletion of Nrf2 promotes immortalization and decreases life span of murine embryonic fibroblasts.

Nuclear factor E2-related factor-2 (Nrf2) transcription factor is one of the main regulators of intracellular redox balance and a sensor of oxidative and electrophilic stress. Low Nrf2 activity is usually associated with carcinogenesis, but Nrf2 is also considered as an oncogene because it increases survival of transformed cells. Because intracellular redox balance alterations are involved in both senescence and tumorigenesis, we investigated the impact of Nrf2 genetic deletion on cellular immortalization and life span of murine embryonic fibroblasts. We report that Nrf2 genetic deletion promotes immortalization due to an early loss of p53-dependent gene expression. However, compared with control cells, immortalized Nrf2-/- murine embryonic fibroblasts exhibited decreased growth, lower cyclin E levels, and impaired expression of NQO1 and cytochrome b5 reductase. Moreover, SirT1 was also significantly reduced in immortalized Nrf2-/- murine embryonic fibroblasts, and these cells exhibited shorter life span. Our results underscore the dual role of Nrf2 in protection against carcinogenesis and in the delay of cellular aging.

Therapeutic use of coenzyme Q10 and coenzyme Q10-related compounds and formulations.

IMPORTANCE OF THE FIELD: Coenzyme Q(10) (CoQ(10)) is found in blood and in all organs. CoQ(10) deficiencies are due to autosomal recessive mutations, ageing-related oxidative stress and carcinogenesis processes, and also statin treatment. Many neurodegenerative disorders, diabetes, cancer and muscular and cardiovascular diseases have been associated with low CoQ(10) levels, as well as different ataxias and encephalomyopathies. AREAS COVERED IN THIS REVIEW: We review the efficacy of a variety of commercial formulations which have been developed to solubilise CoQ(10) and promote its better absorption in vivo, and its use in the therapy of pathologies associated with low CoQ(10) levels, with emphasis in the results of the clinical trials. Also, we review the use of its analogues idebenone and MitoQ. WHAT THE READER WILL GAIN: This review covers the most relevant aspects related with the therapeutic use of CoQ(10), including existing formulations and their effects on its bioavailability. TAKE HOME MESSAGE: CoQ(10) does not cause serious adverse effects in humans and new formulations have been developed that increase CoQ(10) absorption. Oral CoQ(10) is a viable antioxidant strategy in many diseases, providing a significant to mild symptomatic benefit. Idebenone and MitoQ are promising substitutive CoQ(10)-related drugs which are well tolerated and safe.

ES936 stimulates DNA synthesis in HeLa cells independently on NAD(P)H:quinone oxidoreductase 1 inhibition, through a mechanism involving p38 MAPK.

The indolequinone ES936 (5-methoxy-1,2-dimethyl-3-[(4-nitrophenol)methyl]-indole-4,7-dione) is a potent mechanism-based inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1). Here, we report that ES936 significantly stimulated thymidine incorporation in sparse cultures of human adenocarcinoma HeLa cells, but was without effect in dense cultures. Stimulation of DNA synthesis was not related with a DNA repair response because an increase in thymidine incorporation was not observed in cells treated with 2,5 bis-[1-aziridyl]-1,4 benzoquinone, a well-established antitumor quinone that causes DNA damage. Conversely, it was related with an increase of cell growth. NQO1 inhibition was not involved in ES936 stimulation of DNA synthesis, because the same response was observed in cells where NQO1 expression had been knocked down by small interfering RNA. Stimulation of DNA synthesis was reverted by treatment with ambroxol, a SOD mimetic, and by pyruvate, an efficient peroxide scavenger, supporting the involvement of alterations in cellular redox state. Pharmacological inhibition of p38 with either SB203580 or PD169316 completely abolished ES936-stimulated DNA synthesis, indicating the requirement of p38 activity. This is the first report that demonstrates the existence of an ES936-sensitive system which is separate from NQO1, modulating the redox state and cell growth in HeLa cells through a p38-dependent mechanism. Our results show that the effect ES936 exerts on DNA synthesis may be either positive or negative depending on the cellular context and growth conditions.