Evidence for possible role of melatonin in reducing oxidative stress in multiple sclerosis through its effect on SIRT1 and antioxidant enzymes

Mechanical stimulation promotes the maturation of cardiomyocyte-like cells from P19 cells and the function in a mouse model of myocardial infarction

In this study, we aimed to promote the maturation of cardiomyocytes-like cells by mechanical stimulation, and evaluate their therapeutic potential against myocardial infarction. The cyclic tensile strain was used to induce the maturation of cardsiomyocyte-like cells from P19 cells in vitro. Western blot and qPCR assays were performed to examine protein and gene expression, respectively. High-resolution respirometry was used to assay cell function. The induced cells were then evaluated for their therapeutic effect. In vitro, we observed cyclic tensile strain induced P19 cell differentiation into cardiomyocyte-like cells, as indicated by the increased expression of cardiomyocyte maturation-related genes such as Myh6, Myl2, and Gja1. Furthermore, cyclic tensile strain increased the antioxidant capacity of cardiomyocytes by upregulating the expression Sirt1, a gene important for P19 maturation into cardiomyocyte-like cells. High-resolution respirometry analysis of P19 cells following cyclic tensile strain showed enhanced metabolic function. In vivo, stimulated P19 cells enhanced cardiac function in a mouse model of myocardial infarction, and these mice showed decreased infarction-related biomarkers. The current study demonstrates a simple yet effective mean to induce the maturation of P19 cells into cardiomyocyte-like cells, with a promising therapeutic potential for the treatment of myocardial infarction.

L-carnitine protects the lung from radiation-induced damage in rats via the AMPK/SIRT1/TGF-1ß pathway

Radiotherapy (RAD) is a common cancer treatment method, but it can have unintended lung side effects. L-carnitine (LCAR) is an amino acid with antioxidant and anti-inflammatory properties. This study aims to demonstrate the effects of LCAR against radiation-induced acute lung injury and to elucidate its possible protective molecular mechanisms. A total of 32 Wistar albino rats were separated into four groups: control, RAD (10 Gy once on 1st day), RAD + LCAR (intraperitoneally, 200 mg/kg/d, for 10 days), and LCAR. At the end of the experiment, the rats were euthanized, and the lung tissues were collected for histopathological, immunohistochemical, biochemical, and genetic analysis. Emphysema, pronounced hyperemia, increased total oxidant status, and increased caspase-3 and TNF-α immunostainings were all seen in the lung tissues of the RAD group. LCAR treatment reduced these negative effects. In addition, AMPK and SIRT1 gene expressions increased in the RAD + LCAR group compared to the RAD group, while TGF-1ß gene expression decreased. While RAD caused major damage to the lungs of rats, LCAR application reduced this damage through antioxidant, anti-inflammatory, and anti-apoptotic mechanisms. Specifically, LCAR reduced fibrosis while attenuating RAD-induced inflammation and oxidative stress via the AMPK/SIRT1/TGF-1ß pathway. Therefore, LCAR can be considered a supplement to reduce complications associated with RAD.

Oxidative Stress Markers in Multiple Sclerosis

The pathogenesis of multiple sclerosis (MS) is not completely understood, but genetic factors, autoimmunity, inflammation, demyelination, and neurodegeneration seem to play a significant role. Data from analyses of central nervous system autopsy material from patients diagnosed with multiple sclerosis, as well as from studies in the main experimental model of multiple sclerosis, experimental autoimmune encephalomyelitis (EAE), suggest the possibility of a role of oxidative stress as well. In this narrative review, we summarize the main data from studies reported on oxidative stress markers in patients diagnosed with MS and in experimental models of MS (mainly EAE), and case-control association studies on the possible association of candidate genes related to oxidative stress with risk for MS. Most studies have shown an increase in markers of oxidative stress, a decrease in antioxidant substances, or both, with cerebrospinal fluid and serum/plasma malonyl-dialdehyde being the most reliable markers. This topic requires further prospective, multicenter studies with a long-term follow-up period involving a large number of patients with MS and controls.

Exploring the mRNA and Plasma Protein Levels of BDNF, NT4, SIRT1, HSP27, and HSP70 in Multiple Sclerosis Patients and Healthy Controls

Multiple sclerosis (MS) is a chronic, autoimmune neurodegenerative disease affecting the central nervous system. It is a major cause of non-traumatic neurological disability among young adults in North America and Europe. This study focuses on neuroprotective genes (BDNF, NT4/5, SIRT1, HSP70, and HSP27). Gene expression and protein levels of these markers were compared between MS patients and healthy controls. Blood samples were collected from 42 patients with multiple sclerosis (MS) and 48 control subjects without MS. Quantitative real-time PCR was performed to measure the expression of specific genes. The samples were analyzed in duplicate, and the abundance of mRNA was quantified using the 2-ΔCt method. ELISA assay was used to measure the concentration of specific proteins in the plasma samples. The results show that a 3.5-fold decrease in the gene expression of BDNF corresponds to a 1.5-fold downregulation in the associated plasma protein concentration (p < 0.001). Similar trends were observed with NT-4 (five-fold decrease, slight elevation in protein), SIRT1 (two-fold decrease, two-fold protein decrease), HSP70 (four-fold increase, nearly two-fold protein increase), and HSP27 (four-fold increase, two-fold protein increase) (p < 0.001). This study reveals strong correlations between gene expression and protein concentration in MS patients, emphasizing the relevance of these neuroprotective markers in the disease.

Clinical efficacy and safety of melatonin supplementation in multiple sclerosis: a systematic review

BACKGROUND

Melatonin is a neurohormone secreted predominantly by the pineal gland that is demonstrated to be associated with the pathogenesis of multiple sclerosis (MS). This research desires to evaluate the tolerability and beneficial effects of exogenous melatonin supplementations in patients with MS.

METHODS

This study was executed following the PRISMA 2020 statement. Both observational and interventional studies which reported the clinical effectiveness and/or safety of melatonin supplementation in patients with MS were included in this systematic review. Ovid, PubMed, Scopus, Embase, and Web of Science databases were searched and the risk of bias in included studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools based on study design.

RESULTS

Out of 1304 results of database searches, finally, 14 articles, including 7 randomized controlled trials (RCTs), 6 case-control studies, and one quasi-experimental study, were included based on the full-text review. Included phenotypes of MS were mostly relapsing-remitting MS (RRMS) (in 11 studies); it was secondary progressive MS (SPMS) in only one study, and two other studies had a mixture of the different phenotypes. The course of treatment with melatonin supplementation was between 2 weeks and 12 months. There were no substantial safety issues. Although melatonin was associated with enhanced oxidative stress and inflammation status, concerning the clinical benefits, limited studies suggested improvements in sleep conditions, cognitive outcomes, and fatigue in MS.

DISCUSSION

There are insufficient data to support the regular melatonin prescription in MS. Limitations such as the small number of included studies, the diversity of the dosage, route, and duration of melatonin administration, and the diversity of assessment tests lead to unconvincing findings in this study. There is a need for future studies to achieve a comprehensive judgment on this subject.

Dimethylarginine Dimethylaminohydrolase - 1 expression is increased under tBHP-induced oxidative stress regulates nitric oxide production in PCa cells attenuates mitochondrial ROS-mediated apoptosis

Dimethylarginine dimethylaminohydrolase-1 (DDAH1) expression is frequently elevated in different cancers including prostate cancer (PCa) and enhances nitric oxide (NO) production in tumor cells by metabolising endogenous nitric oxide synthase (NOS) inhibitors. DDAH1 protects the PCa cells from cell death and promotes survival. In this study, we have investigated the cytoprotective role of DDAH1 and determined the mechanism of DDAH1 in protecting the cells in tumor microenvironment. Proteomic analysis of PCa cells with stable overexpression of DDAH1 has identified that oxidative stress-related activity is altered. Oxidative stress promotes cancer cell proliferation, survival and causes chemoresistance. A known inducer of oxidative stress, tert-Butyl Hydroperoxide (tBHP) treatment to PCa cells led to elevated DDAH1 level that is actively involved in protecting the PCa cells from oxidative stress induced cell damage. In PC3-DDAH1- cells, tBHP treatment led to higher mROS levels indicating that the loss of DDAH1 increases the oxidative stress and eventually leads to cell death. Under oxidative stress, nuclear Nrf2 controlled by SIRT1 positively regulates DDAH1 expression in PC3 cells. In PC3-DDAH1+ cells, tBHP induced DNA damage is well tolerated compared to wild-type cells while PC3-DDAH1- became sensitive to tBHP. In PC3 cells, tBHPexposure has increased the production of NO and GSH which may be acting as an antioxidant defence to overcome oxidative stress. Furthermore, in tBHP treated PCa cells, DDAH1 is controlling the expression of Bcl2, active PARP and caspase 3. Taken together, these results confirm that DDAH1 is involved in the antioxidant defence system and promotes cell survival.

Efforts Towards Repurposing of Antioxidant Drugs and Active Compounds for Multiple Sclerosis Control

Multiple Sclerosis (MS) is a degenerative disorder of the central nervous system (CNS) with complicated etiology that has not been clearly analyzed until nowadays. Apart from anti-inflammatory, immune modulatory and symptomatic treatments, which are the main tools towards MS control, antioxidant molecules may be of interest. Oxidative stress is a key condition implicated in the disease progression. Reactive species production is associated with immune cell activation in the brain as well as in the periphery, accounting for demyelinating and axonal disruptive processes. This review refers to research articles, of the last decade. It describes biological evaluation of antioxidant drugs, and molecules with pharmaceutical interest, which are not designed for MS treatment, however they seem to have potency against MS. Their antioxidant effect is accompanied, in most of the cases, by anti-inflammatory, immune-modulatory and neuroprotective properties. Compounds with such characteristics are expected to be beneficial in the treatment of MS, alone or as complementary therapy, improving some clinical and mechanistic aspects of the disease. This review also summarizes some of the pathobiological characteristics of MS, as well as the role of oxidative stress and inflammation in the progression of neurodegeneration. It presents known drugs and bioactive compounds with antioxidant, and in many cases, pleiotropic activity that have been tested for their efficacy in MS progression or the experimentally induced MS. Antioxidants may offer reduction or prevention of the disease symptoms and progression. Thus, their results may, combined with already applied treatments, be beneficial for the development of new molecules or the repurposing of drugs and supplements that are used with other indication so far.

Exploring the Role of Neurotransmitters in Multiple Sclerosis: An Expanded Review

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS). Although emerging evidence has shown that changes in neurotransmitter levels in the synaptic gap may contribute to the pathophysiology of MS, their specific role has not been elucidated yet. In this review, we aim to analyze preclinical and clinical evidence on the structural and functional changes in neurotransmitters in MS and critically discuss their potential role in MS pathophysiology. Preclinical studies have demonstrated that alterations in glutamate metabolism may contribute to MS pathophysiology, by causing excitotoxic neuronal damage. Dysregulated interaction between glutamate and GABA results in synaptic loss. The GABAergic system also plays an important role, by regulating the activity and plasticity of neural networks. Targeting GABAergic/glutamatergic transmission may be effective in fatigue and cognitive impairment in MS. Acetylcholine (ACh) and dopamine can also affect the T-mediated inflammatory responses, thereby being implicated in MS-related neuroinflammation. Also, melatonin might affect the frequency of relapses in MS, by regulating the sleep-wake cycle. Increased levels of nitric oxide in inflammatory lesions of MS patients may be also associated with axonal neuronal degeneration. Therefore, neurotransmitter imbalance may be critically implicated in MS pathophysiology, and future studies are needed for our deeper understanding of their role in MS.

Insights into Manganese Superoxide Dismutase and Human Diseases

Redox equilibria and the modulation of redox signalling play crucial roles in physiological processes. Overproduction of reactive oxygen species (ROS) disrupts the body's antioxidant defence, compromising redox homeostasis and increasing oxidative stress, leading to the development of several diseases. Manganese superoxide dismutase (MnSOD) is a principal antioxidant enzyme that protects cells from oxidative damage by converting superoxide anion radicals to hydrogen peroxide and oxygen in mitochondria. Systematic studies have demonstrated that MnSOD plays an indispensable role in multiple diseases. This review focuses on preclinical evidence that describes the mechanisms of MnSOD in diseases accompanied with an imbalanced redox status, including fibrotic diseases, inflammation, diabetes, vascular diseases, neurodegenerative diseases, and cancer. The potential therapeutic effects of MnSOD activators and MnSOD mimetics are also discussed. Targeting this specific superoxide anion radical scavenger may be a clinically beneficial strategy, and understanding the therapeutic role of MnSOD may provide a positive insight into preventing and treating related diseases.

Evidence for novel cell defense mechanisms sustained by dimethyl fumarate in multiple sclerosis patients: the HuR/SOD2 cascade

BACKGROUND

Dimethyl fumarate (DMF) is an effective treatment for relapsing remitting Multiple Sclerosis (MS) and its mechanisms of action encompass immunomodulatory and cytoprotective effects. Despite DMF is known to activate the Nrf2 pathway, Nrf2-independent mechanisms have been also reported and new insights on the underlying molecular mechanisms are still emerging including transcriptional and post-transcriptional events. At this regard, we focused on a small family of RNA-binding proteins, the ELAV-like proteins, that play a pivotal role in post-transcriptional mechanisms and are involved in the pathogenesis of several psychiatric and neurologic disorders. HuR, the ubiquitously expressed member of the family, is implicated in many cellular functions, including survival, inflammation and proper functioning of the immune system. We previously documented the potential entanglement of HuR in MS pathogenesis. In the present work, we explored HuR protein levels in peripheral blood mononuclear cells (PBMCs) from MS patients before and after DMF treatment compared to healthy controls (HC). Considering that HuR may act on various targets, playing a protective role against oxidative stress, our main goals were to evaluate whether manganese-dependent superoxide dismutase transcript (SOD2) could represent a new molecular target of HuR and to study the potential influence of DMF treatment on this interaction.

METHODS

PBMCs from 20 patients with MS and 20 frequency-matched HC by sex and age were used to evaluate HuR, MnSOD (the protein coded by SOD2) and Nrf2 protein content by Western blot, before and after 12 months of DMF treatment. Immunoprecipitation experiments coupled with RNA extraction in PBMCs were performed to explore whether SOD2 mRNA could be physically bound by HuR and whether the expression of MnSOD protein could be affected by 12 months of DMF treatment.

RESULTS

In PBMCs, HuR protein binds SOD2 transcript in HC and in MS patients naïve to disease modifying treatment. The expression of MnSOD protein is positively affected by 12 months of DMF treatment. PBMCs from MS patients have a lower HuR and MnSOD protein content compared to matched HC (HuR: p<0.01, MnSOD: p<0.01). Of interest, 12 months of DMF treatment in MS patients restores the amount of both HuR protein and MnSOD enzyme to the levels observed in HC. We also confirmed that Nrf2 is an HuR target, and we report that its levels are significantly increased in MS patients naïve to disease modifying treatment and remain elevated following DMF administration.

CONCLUSION

SOD2 transcript is a new target of HuR protein. DMF induces an increased expression of HuR protein, which ultimately interacts more strongly with SOD2 transcript promoting the expression of this antioxidant protein. The activation of this molecular cascade can constitute an additional tool that the cells can exploit to counteract the oxidative stress associated with MS development, and can account for the multifaceted molecular mechanisms underlying DMF efficacy in MS.

Chicoric acid does not restore palmitate-induced decrease in irisin levels in PBMCs of newly diagnosed patients with T2D and healthy subjects

Targeting irisin as a myokine/adipokine is a new therapeutic approach in the improvement of insulin-resistance (IR) during type 2 diabetes (T2D). In present study we evaluated the effects of palmitate and chicoric acid (CA) on irisin production in peripheral blood mononuclear cells (PBMCs) of patients with T2D. This study performed on 20 newly diagnosed patients with T2D and 20 healthy subjects. PBMCs treated with palmitate and CA. PPARGC1A and FNDC5 genes expression assessed using qRT-PCR. Irisin levels in cell culture medium measured by ELISA. Palmitate decreased PPARGC1A and FNDC5 genes expression, as well as irisin levels in PBMCs from T2D and healthy volunteers. CA significantly restored palmitate-induced decrease in PPARGC1A gene expression in PBMCs of healthy subjects. Although, FNDC5 gene expression and irisin levels were not induced significantly by CA. In conclusion, palmitate decreases irisin production through down-regulation of PPARGC1A and FNDC5 expressions. However, CA does not effect on irisin pathway.Key pointsPalmitate reduced PPARGC1A and FNDC5 genes expression, as well as irisin secretion in PBMCs.Palmitate-induced decrease in PPARGC1A gene expression significantly has been reversed by CA in PBMCs of healthy subjects.CA did not return palmitate-decreased in FNDC5 gene expression and irisin levels in PBMCs.

Profiling and predicting the problem-solving patterns in China’s research systems: A methodology of intelligent bibliometrics and empirical insights

Uncovering the driving forces, strategic landscapes, and evolutionary mechanisms of China’s research systems is attracting rising interest around the globe. One topic of interest is to understand the problem-solving patterns in China’s research systems now and in the future. Targeting a set of high-quality research articles published by Chinese researchers between 2009 and 2018, and indexed in the Essential Science Indicators database, we developed an intelligent bibliometrics-based methodology for identifying the problem-solving patterns from scientific documents. Specifically, science overlay maps incorporating link prediction were used to profile China’s disciplinary interactions and predict potential cross-disciplinary innovation at a macro level. We proposed a function incorporating word embedding techniques to represent subjects, actions, and objects (SAO) retrieved from combined titles and abstracts into vectors and constructed a tri-layer SAO network to visualize SAOs and their semantic relationships. Then, at a micro level, we developed network analytics for identifying problems and solutions from the SAO network, and recommending potential solutions for existing problems. Empirical insights derived from this study provide clues to understand China’s research strengths and the science policies underlying them, along with the key research problems and solutions that Chinese researchers are focusing on now and might pursue in the future.

Mitochondria, Oxidative Stress, cAMP Signalling and Apoptosis: A Crossroads in Lymphocytes of Multiple Sclerosis, a Possible Role of Nutraceutics

Multiple sclerosis (MS) is a complex inflammatory and neurodegenerative chronic disease that involves the immune and central nervous systems (CNS). The pathogenesis involves the loss of blood–brain barrier integrity, resulting in the invasion of lymphocytes into the CNS with consequent tissue damage. The MS etiology is probably a combination of immunological, genetic, and environmental factors. It has been proposed that T lymphocytes have a main role in the onset and propagation of MS, leading to the inflammation of white matter and myelin sheath destruction. Cyclic AMP (cAMP), mitochondrial dysfunction, and oxidative stress exert a role in the alteration of T lymphocytes homeostasis and are involved in the apoptosis resistance of immune cells with the consequent development of autoimmune diseases. The defective apoptosis of autoreactive lymphocytes in patients with MS, allows these cells to perpetuate, within the CNS, a continuous cycle of inflammation. In this review, we discuss the involvement in MS of cAMP pathway, mitochondria, reactive oxygen species (ROS), apoptosis, and their interaction in the alteration of T lymphocytes homeostasis. In addition, we discuss a series of nutraceutical compounds that could influence these aspects.

Exosomes from SIRT1-Overexpressing ADSCs Restore Cardiac Function by Improving Angiogenic Function of EPCs

Acute myocardial infarction (AMI) is one of the leading causes of mortality in cardiovascular diseases. The aim of this study was to investigate whether exosomes from Sirtuin 1 (SIRT1)-overexpressing adipose-derived stem cells (ADSCs) had a protective effect on AMI. The expression of C-X-C chemokine receptor type 7 (CXCR7) was significantly downregulated in peripheral blood endothelial progenitor cells (EPCs) from AMI patients (AMI-EPCs) compared with that in healthy donors, which coincided with impaired tube formation. The exosomes from SIRT1 overexpression in ADSCs (ADSCs-SIRT1-Exos) increased the expression of C-X-C motif chemokine 12 (CXCL12) and nuclear factor E2 related factor 2 (Nrf2) in AMI-EPCs, which promoted migration and tube formation of AMI-EPCs, and overexpression of CXCR7 helped AMI-EPCs to restore the function of cell migration and tube formation. Moreover, CXCR7 was downregulated in the myocardium of AMI mice, and knockout of CXCR7 exacerbated AMI-induced impairment of cardiovascular function. Injection of ADSCs-SIRT1-Exos increased the survival and promoted the recovery of myocardial function with reduced infarct size and post-AMI left ventricular remodeling, induced vasculogenesis, and decreased AMI-induced myocardial inflammation. These findings showed that ADSCs-SIRT1-Exos may recruit EPCs to the repair area and that this recruitment may be mediated by Nrf2/CXCL12/CXCR7 signaling.

Role of Blueberry Anthocyanin Extract in the Expression of SIRT1 and NF-κB in Rat Lens Epithelial Cells in Experimentally Induced DM

PURPOSE

To investigate the mechanism of the protective effects of blueberry anthocyanin extract (BAE) against oxidative stress and the roles of SIRT1 and NF-κB in the pathogenesis of diabetic cataracts.

METHODS

Male SD rats were randomly divided into a control group (group A) and an experimental group. The rats in the experimental group were intraperitoneally injected with streptozotocin (STZ) (60 mg/kg). Rats with blood glucose levels ≥16.7 mmol/L were considered to have DM. The rats in the experimental group were subdivided into group B (distilled water by oral gavage: 10 ml/kg/day), group C (5% blueberry anthocyanin extract by oral gavage: 10 ml/kg/day), and group D (15% blueberry anthocyanin extract by oral gavage: 10 ml/kg/day), with 15 rats in each group. At the end of 8 weeks, some biochemical parameters, including the expression of SIRT1 and NF-κB by qRT-PCR and western blotting and the activity of SOD and GSH, were measured in lens epithelial cells (LECs).

RESULTS

The lenses of the rats in the control group appeared transparent during the entire 8-week period. Four weeks following STZ injection, cataracts gradually progressed in the experimental rats. SIRT1 expression was upregulated in groups B, C and D compared to the control group. However, the expression of NF-κB decreased in the experimental groups with increasing doses of BAE (p < .05). Our study also showed that the activity of the SOD enzyme and GSH in the LECs of the rats in the experimental group increased with higher doses of BAE.

CONCLUSIONS

The results indicated that BAE significantly delayed the progression of diabetic cataracts in rats. These effects may be due to the dose-dependent antioxidant activity of BAE, which is mediated by enhanced SOD and GSH activities, SIRT1 expression and reduced NF-κB expression. Abbreviations: SD rat: Sprague-Dawley rat; BAE: Blueberry anthocyanin extract; LECs: Lens epithelial cells; SOD: Superoxide dismutase; GSH: Glutathione; DM: Diabetes mellitus; SIRT1: Silent information regulator protein-1; STZ: Streptozotocin; PBS: Phosphate-buffered saline.

An overview of lipidomic analysis in different human matrices of multiple sclerosis

Multiple sclerosis is a chronic inflammatory and neurodegenerative disease of the central nervous system, and it is one of the most common neurological cause of disability in young adults. It is known that several factors contribute to increase the risk of development and pathogenesis of multiple sclerosis, nonetheless, but the true etiology of this pathology remains unknown. Similar to other inflammatory diseases, oxidative stress and lipid peroxidation are also associated to multiple sclerosis. Alterations in the lipid profile seem to be a hallmark of this pathology which can contribute to the dysregulation of lipid homeostasis and lipid metabolism in multiple sclerosis. Lipidomic studies analysed in this review clearly demonstrate the role of lipids in inflammatory processes, in immunity, and in the onset and development of multiple sclerosis. Several investigations reported alterations of some molecular lipid species, in particular, with decrease of fatty acids (FA) 18:2 and 20:4 and total polyunsaturated FA, with compensatory increases of saturated FA with shorter carbon chains. Oxidized phospholipids were reported in few studies as well. Also, it was shown that clinical lipidomics has potential as a tool to aid both in multiple sclerosis diagnosis and therapeutics by allowing a detailed lipidome profiling of the patients suffering with this disease.

Inflammation and Oxidative Stress in Multiple Sclerosis: Consequences for Therapy Development

CNS inflammation is a major driver of MS pathology. Differential immune responses, including the adaptive and the innate immune system, are observed at various stages of MS and drive disease development and progression. Next to these immune-mediated mechanisms, other mediators contribute to MS pathology. These include immune-independent cell death of oligodendrocytes and neurons as well as oxidative stress-induced tissue damage. In particular, the complex influence of oxidative stress on inflammation and vice versa makes therapeutic interference complex. All approved MS therapeutics work by modulating the autoimmune response. However, despite substantial developments in the treatment of the relapsing-remitting form of MS, approved therapies for the progressive forms of MS as well as for MS-associated concomitants are limited and much needed. Here, we summarize the contribution of inflammation and oxidative stress to MS pathology and discuss consequences for MS therapy development.

The role of melatonin in Multiple Sclerosis

Melatonin is a neurohormone mainly produced by the pineal gland following a circadian rhythm. It is characterized as a pleiotropic factor because it not only regulates the wake-sleep rhythm but also exerts antinociceptive, antidepressant, anxiolytic, and immunomodulating properties. Recent studies suggest that dysregulation of melatonin secretion is associated with the pathogenesis of various autoimmune diseases, such as, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and multiple sclerosis (MS). MS is an autoimmune disorder characterized by an abnormal immune response directed against the myelin sheath in the central nervous system, demyelination, oligodendrocyte death, and axonal degeneration. Recent evidence reveals that melatonin secretion is dysregulated in MS patients, suggesting that melatonin could be a potential target for therapeutic intervention. Here, we summarize the available literature regarding the role of melatonin in immune processes relevant for experimental autoimmune encephalomyelitis (EAE), MS, and the current clinical trials of melatonin supplementation in MS patients.

SUMOylation and deacetylation affect NF-κB p65 activity induced by high glucose in human lens epithelial cells

AIM

To explore the effects of IκBα SUMOylation and NF-κB p65 deacetylation on NF-κB p65 activity induced by high glucose in cultured human lens epithelial cells (HLECs).

METHODS

HLECs (SRA01/04) were cultured with 5.5, 25, and 50 mmol/L glucose media for 24h, and with 50 mmol/L glucose media for 0, 12, and 24h respectively. SUMO1 and SIRT1 expressions were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot (WB). IκBα and NF-κB p65 expressions were detected by WB. With NAC, DTT, MG132 or Resveratrol (RSV) treatment, SUMO1 and SIRT1 expressions were detected by WB. Protein expression localizations were examined by immunofluorescence and co-immunofluorescence. The effects of SUMO1 or SIRT1 overexpression, as well as MG132 and RSV, on the nuclear expression and activity of IκBα and NF-κB p65 were analyzed by immunoblot and dual luciferase reporter gene assay.

RESULTS

SUMO1 and SIRT1 expressions were influenced by high glucose in mRNA and protein levels, which could be blocked by NAC or DTT. SUMO1 was down-regulated by using MG132, and SIRT1 was up-regulated under RSV treatment. IκBα nuclear expression was attenuated and NF-κB p65 was opposite under high glucose, while IκBα and NF-κB p65 location was transferred to the nucleus. SUMO1 or SIRT1 overexpression and MG132 or RSV treatment affected the nuclear expression and activity of IκBα and NF-κB p65 under high glucose condition.

CONCLUSION

IκBα SUMOylation and NF-κB p65 deacetylation affect NF-κB p65 activity in cultured HLECs under high glucose, and presumably play a significant role in controlling diabetic cataract.

Melatonin and Multiple Sclerosis: From Plausible Neuropharmacological Mechanisms of Action to Experimental and Clinical Evidence

Multiple sclerosis (MS) is a devastating chronic autoimmune demyelinating disease of the central nervous system (CNS), thought to affect more than 2.5 million people worldwide. Regulation of the sleep-wake cycle might influence disease activity and the frequency of relapses in patients. As melatonin (or sleep hormone) involves the regulation of circadian rhythms, much attention has been paid to the management of MS symptoms with melatonin. This review describes the pharmacological mechanisms underlying the neuroprotective effects of melatonin and recent clinical evidence from MS patients. Apparent risks and benefits of melatonin therapies are also discussed. Various in vivo and clinical data presented in this up-to-date review suggest that melatonin may possibly possess a protective role against the behavioral deficits and neuropathological characteristics of MS. Multiple mechanisms of the neuroprotective effects of melatonin such as mitochondrial protection and antioxidant, anti-inflammatory, and anti-apoptotic properties, as well as its anti-demyelinating function are also discussed. A large body of evidence shows that melatonin potently regulates the immune system, demyelination, free radical generation, and inflammatory responses in neural tissue, which are mediated by multiple signal transduction cascades. In the present article, we focus on different pathways that are targeted by melatonin to prevent the development and progression of MS.

Melatonin improves the structure and function of autografted mice ovaries through reducing inflammation: A stereological and biochemical analysis

Melatonin has anti-oxidant, anti-inflammatory and anti-apoptotic properties. We aimed to investigate the effect of melatonin on the structure and function of mice ovaries following autograft transplantation. NMRI mice were divided into: control, autografted + saline, autografted + melatonin (20 mg/kg/day i.p. injection for 1 day before until 7 days after transplantation). 28 days post transplantation, ovary compartments were studied stereologically. Follicle apoptosis and the level of progesterone and estradiol were also measured. The inflammation, serum MDA concentration and total antioxidant capacity were also assessed on day 7 post transplantation. The total volume of the ovary, cortex and medulla (P < 0.05) and the number of different types of follicles (P < 0.001), the concentration of IL-10, progesterone and estradiol (P < 0.001) and TAC (P < 0.01) significantly decreased in the autografted + saline group compared to the control. The levels of IL-6 (P < 0.01), TNF-α, MDA and the apoptotic rate (P < 0.001) increased significantly in the autografted + saline group compared to the control, while the total volume of the ovary, cortex and medulla (P < 0.05) and the number of different types of follicles (P < 0.001), the concentration of IL-10, progesterone and estradiol (P < 0.001) and TAC (P < 0.01) significantly increased in the autografted + melatonin group compared to the autografted + saline group. The levels of IL-6 (P < 0.01), TNF-α, MDA and the apoptotic rate (P < 0.001) decreased significantly in the autografted + melatonine group compared to the autografted + saline group. In the autografted + melatonin group, the localization of CD31-positive cells in the theca layer was similar to the control group. Melatonin can improve the structure and function of the grafted ovary.

Sirtuins in Multiple Sclerosis: The crossroad of neurodegeneration, autoimmunity and metabolism

Multiple Sclerosis (MS) is a challenging and disabling condition particularly in the secondary progressive (SP) phase of this disease. The available treatments cannot ameliorate or stop disease progression in this phase, and there is an urgent need to focus on effective therapies and the molecular pathways involved SPMS. Given the significant impact of neurodegeneration, autoimmunity and metabolic alterations in MS, focusing on the molecules that target these different pathways could help in finding new treatments. Sirtuins (SIRTs) are NAD⁺ dependent epigenetic and metabolic regulators, which have critical roles in the physiology of central nervous system, immune system and metabolism. Based on these facts, SIRTs are crucial candidates of therapeutic targets in MS and collecting the information related to MS disease for each SIRT individually is noteworthy and highlights the lack of investigation in each part. In this review we summarized the role of different sirtuins as key regulator in neurodegeneration, autoimmunity and metabolism pathways. We also clarify the rationale behind selecting SIRTs as therapeutic targets in MS disease by collecting the researches showing alteration of these proteins in human samples of MS patients and animal model of MS, and also the improvement of modeled animals after SIRT-directed treatments.

Lipoic Acid and Other Antioxidants as Therapies for Multiple Sclerosis

Oxidative stress (OS), when oxidative forces outweigh endogenous and nutritional antioxidant defenses, contributes to the pathophysiology of multiple sclerosis (MS). Evidence of OS is found during acute relapses, in active inflammatory lesions, and in chronic, longstanding plaques. OS results in both ongoing inflammation and neurodegeneration. Antioxidant therapies are a rational strategy for people with MS with all phenotypes and disease durations. PURPOSE OF REVIEW: To understand the function of OS in health and disease, to examine the contributions of OS to MS pathophysiology, and to review current evidence for the effects of selected antioxidant therapies in people with MS (PwMS) with a focus on lipoic acid (LA). RECENT FINDINGS: Studies of antioxidant interventions in both animal and in vivo models result in reductions in serum markers of OS and increases in levels and activity of antioxidant enzymes. Antioxidant trials in PwMS, while generally underpowered, detect short-term improvements in markers of OS and antioxidant defenses, and to a lesser extent, in clinical symptoms (fatigue, depression). The best evidence to date is a 2-year trial of LA in secondary progressive MS which demonstrated a significant reduction of whole-brain atrophy and trend toward improvement in walking speed. Antioxidant therapy is a promising approach to treat MS across the spectrum and duration of disease. Rigorous and well-powered trials are needed to determine their therapeutic benefits.

Melatonin protects chronic kidney disease mesenchymal stem cells against senescence via PrPC -dependent enhancement of the mitochondrial function

Although mesenchymal stem cell (MSC)-based therapy is a treatment strategy for ischemic diseases associated with chronic kidney disease (CKD), MSCs of CKD patients undergo accelerated senescence, with decreased viability and proliferation upon uremic toxin exposure, inhibiting their utility as a potent stem cell source for transplantation therapy. We investigated the effects of melatonin administration in protecting against cell senescence and decreased viability induced by pathophysiological conditions near the engraftment site. MSCs harvested from CKD mouse models were treated with H₂ O₂ to induce oxidative stress. CKD-derived MSCs exhibited greater oxidative stress-induced senescence than normal-mMSCs, while melatonin protected CKD-mMSCs from H₂ O₂ and associated excessive senescence. The latter was mediated by PrP^C -dependent mitochondrial functional enhancement; melatonin upregulated PrP^C , which bound PINK1, thus promoting mitochondrial dynamics and metabolism. In vivo, melatonin-treated CKD-mMSCs survived longer, with increased secretion of angiogenic cytokines in ischemic disease engraftment sites. CKD-mMSCs are more susceptible to H₂ O₂ -induced senescence than normal-mMSCs, and melatonin administration protects CKD-mMSCs from excessive senescence by upregulating PrP^C and enhancing mitochondrial function. Melatonin showed favorable therapeutic effects by successfully protecting CKD-mMSCs from related ischemic conditions, thereby enhancing angiogenesis and survival. These results elucidate the mechanism underlying senescence inhibition by melatonin in stem cell-based therapies using mouse-derived CKD-mMSCs.

Multiple Immune-Inflammatory and Oxidative and Nitrosative Stress Pathways Explain the Frequent Presence of Depression in Multiple Sclerosis

Patients with a diagnosis of multiple sclerosis (MS) or major depressive disorder (MDD) share a wide array of biological abnormalities which are increasingly considered to play a contributory role in the pathogenesis and pathophysiology of both illnesses. Shared abnormalities include peripheral inflammation, neuroinflammation, chronic oxidative and nitrosative stress, mitochondrial dysfunction, gut dysbiosis, increased intestinal barrier permeability with bacterial translocation into the systemic circulation, neuroendocrine abnormalities and microglial pathology. Patients with MS and MDD also display a wide range of neuroimaging abnormalities and patients with MS who display symptoms of depression present with different neuroimaging profiles compared with MS patients who are depression-free. The precise details of such pathology are markedly different however. The recruitment of activated encephalitogenic Th17 T cells and subsequent bidirectional interaction leading to classically activated microglia is now considered to lie at the core of MS-specific pathology. The presence of activated microglia is common to both illnesses although the pattern of such action throughout the brain appears to be different. Upregulation of miRNAs also appears to be involved in microglial neurotoxicity and indeed T cell pathology in MS but does not appear to play a major role in MDD. It is suggested that the antidepressant lofepramine, and in particular its active metabolite desipramine, may be beneficial not only for depressive symptomatology but also for the neurological symptoms of MS. One clinical trial has been carried out thus far with, in particular, promising MRI findings.

Melatonin attenuates postovulatory oocyte dysfunction by regulating SIRT1 expression

The quality of postovulatory metaphase II oocytes undergoes a time-dependent deterioration as a result of the aging process. Melatonin is considered to be an anti-aging agent. However, the underlying mechanisms of how melatonin improves the quality of postovulatory aged oocytes remain largely unclear. In this study, by using mouse model, we found that there were elevated reactive oxygen species levels and impaired mitochondrial function demonstrated by reduced mitochondrial membrane potential and increased mitochondrial aggregation in oocytes aged 24 h, accompanied by an increased number of meiotic errors, unregulated autophagy-related proteins and early apoptosis, which led to decreased oocyte quality and disrupted developmental competence. However, all of these events can be largely prevented by supplementing the oocyte culture medium with 10−3 M melatonin. Additionally, we found that the expression of sirtuin family members (SIRT1, 2 and 3) was dramatically reduced in aged oocytes. In addition,in vitrosupplementation with melatonin significantly upregulated the expression of SIRT1 and antioxidant enzyme MnSOD, but this action was not observed for SIRT2 and SIRT3. Furthermore, the protective effect of melatonin on the delay of oocyte aging vanished when the SIRT1 inhibitor EX527 was used to simultaneously treat the oocytes with melatonin. Consistent with this finding, we found that the postovulatory oocyte aging process was markedly attenuated when the oocytes were treated with the SIRT1 activator SRT1720. In conclusion, our data strongly indicate that melatonin delays postovulatory mouse oocyte aging via a SIRT1–MnSOD-dependent pathway, which may provide a molecular mechanism support for the further application of melatonin in the assisted reproductive technology field.

Spasticity Treatment Ameliorates the Efficacy of Melatonin Therapy in Experimental Autoimmune Encephalomyelitis (EAE) Mouse Model of Multiple Sclerosis

Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease in the central nervous system (CNS). Melatonin is an effective treatment in MS patients and experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Melatonin secretion peaks at 2 AM, concomitant with the time at which the muscles are resting and the body is exerting its antioxidant activity. The current study was designed to investigate combination treatment of baclofen, a muscle relaxant drug, and melatonin in EAE mice. Results showed that melatonin (Mel) alone or in combination with baclofen (Bac + Mel) reduced clinical scores and demyelination by significantly increasing myelin oligodendrocyte glycoprotein (MOG) levels, a marker for mature oligodendrocytes, compared to EAE mice. Moreover, Mel or Bac + Mel therapy caused a significant increase in IL-4 serum levels, an anti-inflammatory cytokine, whereas IFN-γ serum levels, a pro-inflammatory cytokine, were significantly reduced. On the other hand, Mel or Bac + Mel caused a significant reduction in malondialdehyde (MDA) levels, a marker of oxidative stress, in comparison to EAE mice. In contrast, the activity of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) was significantly increased in Mel and Bac + Mel groups. In summary, combination therapy improved clinical scores and tend to enhance the efficiency of melatonin treatment by further promoting remyelination, decreasing inflammation, and stimulating the activity of antioxidant enzymes, which suggests that prior spasticity treatment increases the efficacy of melatonin therapy in EAE mouse model of MS. Further experimental and clinical studies are needed to ensure the beneficial role of this combination strategy.

Combination therapy of lovastatin and AMP-activated protein kinase activator improves mitochondrial and peroxisomal functions and clinical disease in experimental autoimmune encephalomyelitis model

Recent studies report that loss and dysfunction of mitochondria and peroxisomes contribute to the myelin and axonal damage in multiple sclerosis (MS). In this study, we investigated the efficacy of a combination of lovastatin and AMP-activated protein kinase (AMPK) activator (AICAR) on the loss and dysfunction of mitochondria and peroxisomes and myelin and axonal damage in spinal cords, relative to the clinical disease symptoms, using a mouse model of experimental autoimmune encephalomyelitis (EAE, a model for MS). We observed that lovastatin and AICAR treatments individually provided partial protection of mitochondria/peroxisomes and myelin/axons, and therefore partial attenuation of clinical disease in EAE mice. However, treatment of EAE mice with the lovastatin and AICAR combination provided greater protection of mitochondria/peroxisomes and myelin/axons, and greater improvement in clinical disease compared with individual drug treatments. In spinal cords of EAE mice, lovastatin-mediated inhibition of RhoA and AICAR-mediated activation of AMPK cooperatively enhanced the expression of the transcription factors and regulators (e.g. PPARα/β, SIRT-1, NRF-1, and TFAM) required for biogenesis and the functions of mitochondria (e.g. OXPHOS, MnSOD) and peroxisomes (e.g. PMP70 and catalase). In summary, these studies document that oral medication with a combination of lovastatin and AICAR, which are individually known to have immunomodulatory effects, provides potent protection and repair of inflammation-induced loss and dysfunction of mitochondria and peroxisomes as well as myelin and axonal abnormalities in EAE. As statins are known to provide protection in progressive MS (Phase II study), these studies support that supplementation statin treatment with an AMPK activator may provide greater efficacy against MS.

SIRT1 exhibits antioxidative effects in HT22 cells induced by tert-butyl alcohol

Tertiary butyl alcohol (TBA) is a principal metabolite of methyl tertiary-butyl ether (MTBE), a common pollutant worldwide in the ground or underground water, which is found to produce nervous system damage. Nevertheless, few data regarding the effects of TBA has been reported. Studies indicated that oxidative stress plays a pivotal role in MTBE neurotoxic mechanism. Sirtuin 1 (SIRT1) has been reported to exert a neuroprotective effect on various neurologic diseases via resistance to oxidative stress by deacetylating its substrates. In this study, we examined levels of oxidative stress after exposure to TBA for 6 h in HT22 cells and HT22 cells with SIRT1 silencing (transfected with SIRT1 siRNA) or high expression (preconditioned with agonists SRT1720). We found that TBA activated oxidative stress by increasing generation of intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and Oxidized glutathione (GSSG), and decreasing contents of superoxide dismutase (SOD) and glutathione reductase (GSH). In additional, levels of TBA-induced oxidative stress were aggravated when SIRT1 silenced but alleviated when SIRT1 enhanced. Our study indicated that SIRT1 mitigated oxidative stress induced by TBA.

Melatonin reduces inflammatory response in peripheral T helper lymphocytes from relapsing-remitting multiple sclerosis patients

Multiple sclerosis (MS) is a neuroinflammatory disease of the central nervous system in which the immune system plays a central role. In particular, effector populations such as T helper (Th) 1, Th9, Th17, and Th22 cells are involved in disease development, whereas T regulatory cells (Tregs) are associated with the resolution of the disease. Melatonin levels are impaired in patients with MS, and exogenous melatonin ameliorates the disease in MS animal models by modulating the Th1/Th17/Treg responses and also improves quality of life and several symptoms in patients with MS. However, no study has examined melatonin's effect on T cells from relapsing-remitting MS (RR-MS) patients. Therefore, the objectives of the present study were to evaluate the effects of the in vitro administration of melatonin to peripheral blood mononuclear cells (PBMCs) from 64 RR-MS patients and 64 sex- and age-matched healthy subjects on Th1, Th9, Th17, Th22, and Treg responses and to analyze the expression of the melatonin effector/receptor system in these cells. Melatonin decreased Th1 and Th22 responses in patients, whereas it did not affect the Th17 and Treg subsets. Melatonin also promoted skewing toward a more protective cytokine microenvironment, as shown by an increased anti-inflammatory/Th1 ratio. Furthermore, for the first time, we describe the overexpression of the melatonin effector/receptor system in PBMCs from patients with MS; this alteration might be relevant to the disease because acetylserotonin O-methyltransferase expression significantly correlates with disease progression and T effector/regulatory responses in patients. Therefore, our data suggest that melatonin may be an effective treatment for MS.

Oxidative Modification of Blood Serum Proteins in Multiple Sclerosis after Interferon Beta and Melatonin Treatment

Multiple sclerosis (MS) is a disease involving oxidative stress (OS). This study was aimed at examination of the effect of melatonin supplementation on OS parameters, especially oxidative protein modifications of blood serum proteins, in MS patients. The study included 11 control subjects, 14 de novo diagnosed MS patients with the relapsing-remitting form of MS (RRMS), 36 patients with RRMS receiving interferon beta-1b (250 μg every other day), and 25 RRMS patients receiving interferon beta-1b plus melatonin (5 mg daily). The levels of N′-formylkynurenine, kynurenine, dityrosine, carbonyl groups, advanced glycation products (AGEs), advanced oxidation protein products (AOPP), and malondialdehyde were elevated in nontreated RRSM patients. N′-Formylkynurenine, kynurenine, AGEs, and carbonyl contents were decreased only in the group treated with interferon beta plus melatonin, while dityrosine and AOPP contents were decreased both in the group of patients treated with interferon beta and in the group treated with interferon beta-1b plus melatonin. These results demonstrate that melatonin ameliorates OS in MS patients supporting the view that combined administration of interferon beta-1b and melatonin can be more effective in reducing OS in MS patients than interferon beta-1b alone.

Melatonin counteracts cobalt nanoparticle‑induced cytotoxicity and genotoxicity by deactivating reactive oxygen species‑dependent mechanisms in the NRK cell line

Cobalt nanoparticles (CoNPs) released from metal-on-metal implants have caused considerable concern. Oxidative stress is associated with the mechanism underlying cobalt-induced cytotoxicity and genotoxicity. The indolamine melatonin exhibits protective effects against damage induced by metals. The present study investigated the in vitro effects of melatonin on the cytotoxicity and genotoxicity induced by CoNPs. CoNPs (20–50 nm in diameter) were employed in the present study. NRK rat kidney cells were exposed to various concentrations of CoNPs for different durations. The results of the current study demonstrated that CoNPs significantly increased reactive oxygen species (ROS) production and reduced cell viability, as determined by dichlorofluorescein diacetate, and Cell Counting Kit-8 and lactate dehydrogenase leakage assays, respectively. Furthermore, western blot analysis demonstrated that CoNPs led to an increase in the ratio of Bcl-2-associated X/Bcl-2, and the expression of cleaved caspase-3 was upregulated, which indicated increased apoptosis levels. Genotoxicity was detected by a comet assay, which revealed a significant induction in DNA damage, as determined by increases in the tail DNA % and olive tail moment. Phosphorylated-histone H2AX foci analyses by immunofluorescence also demonstrated that CoNPs induced DNA-double strand breaks. However, cellular treatment with melatonin reduced the effects of CoNPs on NRK cells by reducing the production of ROS. The results of the present study demonstrated that CoNPs induced cytotoxicity and genotoxicity by increasing oxidative stress, and melatonin may have pharmacological potential in protecting against the damaging effects of CoNPs following total hip arthroplasty.

Seasonality and autoimmune diseases: The contribution of the four seasons to the mosaic of autoimmunity

Autoimmune diseases (ADs) are a heterogeneous groups of diseases that occur as a results of loss of tolerance to self antigens. While the etiopathogeneis remain obscure, different environmental factors were suggested to have a role in the development of autoimmunity, including infections, low vitamin D levels, UV radiation, and melatonin. Interestingly, such factors possess seasonal variation patterns that could influence disease development, severity and progression. Vitamin D levels which reach a nadir during late winter and early spring is correlated with increased disease activity, clinical severity as well as relapse rates in several disease entities including multiple sclerosis (MS), non-cutaneous flares of systemic lupus erythematosus (SLE), psoriasis, and rheumatoid arthritis (RA). Additionally, immunomodulatory actions of melatonin secretion ameliorate the severity of several ADs including MS and SLE. Melatonin levels are lowest during spring, a finding that correlates with the highest exacerbation rates of MS. Further, melatonin is postulated to be involved in the etiopathogenesis of inflammatory bowel diseases (IBD) through it influence on adhesion molecule and therefore transcription factor expression. Moreover, infections can mount to ADs through pro-inflammatory cytokine release and human antigen mimicry. Seasonal patterns of infectious diseases are correlated with the onset and exacerbation of ADs. During the winter, increased incidence of Epstein-Barr virus (EBV) infectious are associated with MS and SLE flares/onset respectively. In addition, higher Rotavirus infections during the winter precedes type 1 diabetes mellitus onset (T1DM). Moreover, Escherichia coli (E. coli) infection prior to primary biliary cirrhosis (PBC) and T1DM disease onset subsequent to Coxachievirus infections are seen to occur during late summer, a finding that correlate with infectious agents' pattern of seasonality. In this review, the effects of seasonality on the onset, relapses and activity of various ADs were discussed. Consideration of seasonal variation patterns of ADs can possibly provide clues to diseases pathogenesis and lead to development of new approaches in treatment and preventative care.

Long-term melatonin treatment delays ovarian aging

Ovarian aging is characterized by gradual declines in oocyte quantity and quality. Melatonin is considered an anti-aging agent due to its cytoprotective actions as an antioxidant. This study examined whether long-term melatonin treatment would delay ovarian aging in mice. Female ICR mice (10 weeks old) were given melatonin-containing water (100 μg/mL; melatonin) or water only until 43 weeks of age. Their oocytes were recovered from the oviduct, and in vitro fertilization was performed. The ovaries were used for a histological analysis of the number of follicles. The mRNA expression of the aging-related sirtuin genes (SIRT1, SIRT3) and the autophagy-related gene (LC3) and the telomere length of the ovarian chromosomes were analyzed. Transcriptome changes in the ovaries were also characterized using microarray. The number of ovulated oocytes decreased with age; however, it was greater in melatonin-treated mice than that from control animals. The decreased fertilization rate and blastocyst rate during aging also were higher in the melatonin-treated mice than in the controls, as were the numbers of primordial, primary, and antral follicles. The mRNA expression of SIRT1 and LC3 and telomere length were enhanced due to melatonin treatment. Seventy-eight genes that were downregulated during aging and upregulated by melatonin were identified by a microarray analysis. Forty of these 78 genes were ribosome-related genes, and a free radical scavenging network was identified. The present results indicate that melatonin delays ovarian aging by multiple mechanisms including antioxidant action, maintaining telomeres, stimulating SIRT expression and ribosome function, and by reducing autophagy.

Melatonin and sirtuins: A "not-so unexpected" relationship

Epigenetic modifications, including methylation or acetylation as well as post-transcriptional modifications, are mechanisms used by eukaryotic cells to increase the genome diversity in terms of differential gene expression and protein diversity. Among these modifying enzymes, sirtuins, a class III histone deacetylase (HDAC) enzymes, are of particular importance. Sirtuins regulate the cell cycle, DNA repair, cell survival, and apoptosis, thus having important roles in normal and cancer cells. Sirtuins can also regulate metabolic pathways by changing preference for glycolysis under aerobic conditions as well as glutaminolysis. These actions make sirtuins a major target in numerous physiological processes as well as in other contexts such as calorie restriction-induced anti-aging, cancer, or neurodegenerative disease. Interestingly, melatonin, a nighttime-produced indole synthesized by pineal gland and many other organs, has important cytoprotective effects in many tissues including aging, neurodegenerative diseases, immunomodulation, and cancer. The pleiotropic actions of melatonin in different physiological and pathological conditions indicate that may be basic cellular targeted for the indole. Thus, much research has focused attention on the potential mechanisms of the indole in modulating expression and/or activity of sirtuins. Numerous findings report a rise in activity, especially on SIRT1, in a diversity of cells and animal models after melatonin treatment. This contrasts, however, with data reporting an inhibitory effect of melatonin on this sirtuin in some tumor cells. This review tabulates and discusses the recent findings relating melatonin with sirtuins, particularly SIRT1 and mitochondrial SIRT3, showing the apparent dichotomy with the differential actions documented in normal and in cancer cells.

Melatonin and the pathologies of weakened or dysregulated circadian oscillators

Dynamic aspects of melatonin's actions merit increasing future attention. This concerns particularly entirely different effects in senescent, weakened oscillators and in dysregulated oscillators of cancer cells that may be epigenetically blocked. This is especially obvious in the case of sirtuin 1, which is upregulated by melatonin in aged tissues, but strongly downregulated in several cancer cells. These findings are not at all controversial, but are explained on the basis of divergent changes in weakened and dysregulated oscillators. Similar findings can be expected to occur in other accessory oscillator components that are modulated by melatonin, among them several transcription factors and metabolic sensors. Another cause of opposite effects concerns differences between nocturnally active laboratory rodents and the diurnally active human. This should be more thoroughly considered in the field of metabolic syndrome and related pathologies, especially with regard to type 2 diabetes and other aspects of insulin resistance. Melatonin was reported to impair glucose tolerance in humans, especially in carriers of the risk allele of the MT₂ receptor gene, MTNR1B, that contains the SNP rs10830963. These findings contrast with numerous reports on improvements of glucose tolerance in preclinical studies. However, the relationship between melatonin and insulin may be more complex, as indicated by loss-of-function mutants of the MT₂ receptor that are also prodiabetic, by the age-dependent time course of risk allele overexpression, by progressive reduction in circadian amplitudes and melatonin secretion, which are aggravated in diabetes. By supporting high-amplitude rhythms, melatonin may be beneficial in preventing or delaying diabetes.

(-)-Epigallocatechin-3-gallate alleviates doxorubicin-induced cardiotoxicity in sarcoma 180 tumor-bearing mice

AIMS

(-)-Epigallocatechin-3-gallate (EGCG), a major green tea polyphenol compound, plays an important role in the prevention of cardiovascular disease and cancer. The present study aimed to investigate the effects of EGCG on doxorubicin (DOX)-induced cardiotoxicity in Sarcoma 180 (S180) tumor-bearing mice.

MAIN METHODS

S180 tumor-bearing mice were established by subcutaneous inoculation of S180 cells attached to the axillary region. The extent of myocardial injury was accessed by the amount of lactate dehydrogenase (LDH) released in serum. Heart tissue was morphologically studied with transmission electron microscopy. Apoptosis, reactive oxygen species (ROS) generation, mitochondrial membrane potential (ΔѰm) as well as calcium concentration were measured by flow cytometric analysis. Expression levels of manganese superoxide dismutase (MnSOD) were analyzed by Western blot.

KEY FINDINGS

Results showed that the combination with EGCG and DOX significantly inhibited tumor growth and enhanced induction of apoptosis compared with DOX alone. Moreover, administration of EGCG could suppress DOX-induced cardiotoxicity as evidenced by alleviating LDH release and apoptosis in cardiomyocyte. EGCG-evoked cardioprotection was in association with the increase of ΔѰm and MnSOD expression. EGCG was also found to attenuate ROS generation and myocardial calcium overload in Sarcoma 180 tumor-bearing mice subjected to DOX.

SIGNIFICANCE

EGCG alleviated DOX-induced cardiotoxicity possibly in part mediated by increasing of MnSOD and Ѱm, reducing myocardial calcium overload and subsequently attenuating the apoptosis and LDH release. Our findings suggest that co-administration of EGCG and DOX have potential as a feasible strategy to mitigate cardiotoxicity of DOX without compromising its chemotherapeutic value.

New Insights into the Role of Oxidative Stress Mechanisms in the Pathophysiology and Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a multifactorial disease of the central nervous system (CNS) characterized by an inflammatory process and demyelination. The etiology of the disease is still not fully understood. Therefore, finding new etiological factors is of such crucial importance. It is suspected that the development of MS may be affected by oxidative stress (OS). In the acute phase OS initiates inflammatory processes and in the chronic phase it sustains neurodegeneration. Redox processes in MS are associated with mitochondrial dysfunction, dysregulation of axonal bioenergetics, iron accumulation in the brain, impaired oxidant/antioxidant balance, and OS memory. The present paper is a review of the current literature about the role of OS in MS and it focuses on all major aspects. The article explains the mechanisms of OS, reports unique biomarkers with regard to their clinical significance, and presents a poorly understood relationship between OS and neurodegeneration. It also provides novel methods of treatment, including the use of antioxidants and the role of antioxidants in neuroprotection. Furthermore, adding new drugs in the treatment of relapse may be useful. The article considers the significance of OS in the current treatment of MS patients.

Environmental control of autoimmune inflammation in the central nervous system

Multiple sclerosis (MS) is a chronic autoimmune inflammatory demyelinating disorder of the central nervous system (CNS), which causes severe disability and requires extensive medical attention and treatment. While the infiltration of pathogenic immune cells into the CNS leads to the formation of inflammatory lesions in its initial relapsing-remitting stage, late stages of MS are characterized by progressive neuronal loss and demyelination even without continued interaction with the peripheral immune compartment. Several genetic and environmental factors modulate and influence these processes on multiple levels. Genetic variants confer a predisposition for the development of MS, but are not accessible to therapeutic intervention as of today. However, migration studies suggest that environmental factors influence disease development, activity and progression. This article reviews mechanisms of disease pathogenesis in MS and their modulation by environmental factors such as geographical localization, the gut microbiome and the diet.

RGS2 expression predicts amyloid-β sensitivity, MCI and Alzheimer's disease: genome-wide transcriptomic profiling and bioinformatics data mining

Alzheimer's disease (AD) is the most frequent cause of dementia. Misfolded protein pathological hallmarks of AD are brain deposits of amyloid-β (Aβ) plaques and phosphorylated tau neurofibrillary tangles. However, doubts about the role of Aβ in AD pathology have been raised as Aβ is a common component of extracellular brain deposits found, also by in vivo imaging, in non-demented aged individuals. It has been suggested that some individuals are more prone to Aβ neurotoxicity and hence more likely to develop AD when aging brains start accumulating Aβ plaques. Here, we applied genome-wide transcriptomic profiling of lymphoblastoid cells lines (LCLs) from healthy individuals and AD patients for identifying genes that predict sensitivity to Aβ. Real-time PCR validation identified 3.78-fold lower expression of RGS2 (regulator of G-protein signaling 2; P=0.0085) in LCLs from healthy individuals exhibiting high vs low Aβ sensitivity. Furthermore, RGS2 showed 3.3-fold lower expression (P=0.0008) in AD LCLs compared with controls. Notably, RGS2 expression in AD LCLs correlated with the patients' cognitive function. Lower RGS2 expression levels were also discovered in published expression data sets from postmortem AD brain tissues as well as in mild cognitive impairment and AD blood samples compared with controls. In conclusion, Aβ sensitivity phenotyping followed by transcriptomic profiling and published patient data mining identified reduced peripheral and brain expression levels of RGS2, a key regulator of G-protein-coupled receptor signaling and neuronal plasticity. RGS2 is suggested as a novel AD biomarker (alongside other genes) toward early AD detection and future disease modifying therapeutics.

Nrf2/antioxidant defense pathway is involved in the neuroprotective effects of Sirt1 against focal cerebral ischemia in rats after hyperbaric oxygen preconditioning

Sirtuin 1 (Sirt1) is a class III histone deacetylase involved in neuroprotection induced by hyperbaric oxygen preconditioning (HBO-PC) in animal models of ischemia. However, the underlying mechanisms remain to be illustrated. In the present study, rats exposed to middle cerebral artery occlusion (MCAO) were used to establish an ischemic stroke model. The infarct volume ratio, neurobehavioral score, and expressions of Sirt1, nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), and superoxide dismutase 1 (SOD1) were evaluated at 7 days after reperfusion, and the level of malondialdehyde (MDA) was used to assess oxidative stress. HBO-PC increased the expression of Sirt1 and reduced infarct volume ratio and neurobehavioral deficit in MCAO rats. Meanwhile, HBO-PC also increased expression of Nrf2, HO-1, and SOD1 and decreased MDA content. Furthermore, either Sirt1 or Nrf2 knockdown by short interfering RNA (siRNA) inhibited the expression of Nrf2, HO-1, and SOD1 and eliminated the neuroprotective effects of HBO-PC. Taken together, the results suggest that the Nrf2/antioxidant defense pathway is involved in the long lasting neuroprotective effects of Sirt1 induced by HBO-PC against transient focal cerebral ischemia.