SIRT1 is decreased during relapses in patients with multiple sclerosis

Multiple sclerosis disease activity, a multi-biomarker score of disease activity and response to treatment in multiple sclerosis

Regular assessment of disease activity in relapsing-remitting multiple sclerosis (RRMS) is required to optimize clinical outcomes. Biomarkers can be a valuable tool for measuring disease activity in multiple sclerosis (MS) if they reflect the pathological processes underlying MS pathogenicity. In this pilot study, we combined multiple biomarkers previously analyzed in RRMS patients into an MS disease activity (MSDA) score to evaluate their ability to predict relapses and treatment response to glatiramer acetate (GA). Response Gene to Complement 32 (RGC-32), FasL, IL-21, SIRT1, phosphorylated SIRT1 (p-SIRT1), and JNK1 p54 levels were used to generate cut-off values for each biomarker. Any value below the cutoff for RGC-32, FasL SIRT1, or p-SIRT1 or above the cutoff for IL-21 or JNK1 p54 was given a +1 value, indicating relapse or lack of response to GA. Any value above the cutoff value for RGC-32, FasL, SIRT1, p-SIRT1 or below that for IL-21 or JNK1 p54 was given a -1 value, indicating clinical stability or response to GA. An MSDA score above +1 indicated a relapse or lack of response to treatment. An MSDA score below -1 indicated clinical stability or response to treatment. Our results showed that the MSDA scores generated using either four or six biomarkers had a higher sensitivity and specificity and significantly correlated with the expanded disability status scale. Although these results suggest that the MSDA test can be useful for monitoring therapeutic response to biologic agents and assessing clinically challenging situations, the present findings need to be confirmed in larger studies.

Sirtuins and Metabolism Biomarkers in Relapsing-Remitting and Secondary Progressive Multiple Sclerosis: a Correlation Study with Clinical Outcomes and Cognitive Impairments

Multiple sclerosis (MS) is a primary inflammatory demyelinating disease with different clinical courses and subtypes. The present study aimed to determine whether mitochondrial dysfunction and sirtuins 1 and 3, as metabolism and epigenetic modifying factors, might contribute to MS disease progression measured by physical disability and cognitive impairment.The volunteers (n = 20 controls, n = 59 MS) were recruited and assessed for cognitive function and disability scores; then, patients were clinically classified as relapsing-remitting (RR) in remission phase, RR in relapse phase, and secondary progressive MS. We measured sirtuin (SIRT) 1 and 3 levels, mitochondrial complex I, IV, aconitase, and α-ketoglutarate dehydrogenase (α-KGD) activity in the peripheral blood mononuclear cells (PBMCs). Furthermore, SIRT1, pyruvate, lactate, and cytochrome c (Cyt c) were determined in plasma. Finally, we performed postmortem tissue immunohistochemistry to assess the level of SIRT1 and SIRT3 in the brain lesions of patients with MS.Increased disability and cognitive impairment in patients were correlated. Plasma level of lactate showed a correlation with the disability in MS patients; moreover, a trend toward increased Cyt c plasma level was observed. Investigation of PBMCs exhibited decreased SIRT1 during the relapse phase along with a reduced complex IV activity in all MS subgroups. α-KGD activity was significantly increased in the RR-remission, and SIRT3 was elevated in RR-relapse group. This elevation correlated with disability and cognitive impairment. Finally, immunohistochemistry demonstrated increased levels of SIRT1 and 3 in the brain active lesion of patients with MS.Our data suggest that mitochondrial dysfunction and alteration in some epigenetics and metabolism modifying factors in the CNS and peripheral blood cells may contribute or correlate with MS progression.

Unraveling the Epigenetic Landscape: Insights into Parkinson's Disease, Amyotrophic Lateral Sclerosis, and Multiple Sclerosis

Parkinson's disease (PD), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS) are examples of neurodegenerative movement disorders (NMDs), which are defined by a gradual loss of motor function that is frequently accompanied by cognitive decline. Although genetic abnormalities have long been acknowledged as significant factors, new research indicates that epigenetic alterations are crucial for the initiation and development of disease. This review delves into the complex interactions that exist between the pathophysiology of NMDs and epigenetic mechanisms such DNA methylation, histone modifications, and non-coding RNAs. Here, we examine how these epigenetic changes could affect protein aggregation, neuroinflammation, and gene expression patterns, thereby influencing the viability and functionality of neurons. Through the clarification of the epigenetic terrain underpinning neurodegenerative movement disorders, this review seeks to enhance comprehension of the underlying mechanisms of the illness and augment the creation of innovative therapeutic strategies.

Unveiling the interplay of AMPK/SIRT1/PGC-1α axis in brain health: Promising targets against aging and NDDs

The escalating prevalence of neurodegenerative diseases (NDDs) within an aging global population presents a pressing challenge. The multifaceted pathophysiological mechanisms underlying these disorders, including oxidative stress, mitochondrial dysfunction, and neuroinflammation, remain complex and elusive. Among these, the AMPK/SIRT1/PGC-1α pathway emerges as a pivotal network implicated in neuroprotection against these destructive processes. This review sheds light on the potential therapeutic implications of targeting this axis, specifically emphasizing the promising role of flavonoids in mitigating NDD-related complications. Expanding beyond conventional pharmacological approaches, the exploration of non-pharmacological interventions such as exercise and calorie restriction (CR), coupled with the investigation of natural compounds, offers a beacon of hope. By strategically elucidating the intricate connections within these pathways, this review aims to pave the ways for novel multi-target agents and interventions, fostering a renewed optimism in the quest to combat and manage the debilitating impacts of NDDs on global health and well-being.

HERVs: Expression Control Mechanisms and Interactions in Diseases and Human Immunodeficiency Virus Infection

Human endogenous retroviruses (HERVs) are the result of retroviral infections acquired millions of years ago; nowadays, they compose around 8% of human DNA. Multiple mechanisms have been employed for endogenous retroviral deactivation, rendering replication and retrotransposition defective, while some of them have been co-opted to serve host evolutionary advantages. A pleiad of mechanisms retains the delicate balance of HERV expression in modern humans. Thus, epigenetic modifications, such as DNA and histone methylation, acetylation, deamination, chromatin remodeling, and even post-transcriptional control are recruited. In this review, we aim to summarize the main HERV silencing pathways, revisit paradigms of human disease with a HERV component, and emphasize the human immunodeficiency virus (HIV) and HERV interactions during HIV infection.

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.

Methyl-CpG-Binding Protein 2 Emerges as a Central Player in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

MECP2 and its product methyl-CpG binding protein 2 (MeCP2) are associated with multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), which are inflammatory, autoimmune, and demyelinating disorders of the central nervous system (CNS). However, the mechanisms and pathways regulated by MeCP2 in immune activation in favor of MS and NMOSD are not fully understood. We summarize findings that use the binding properties of MeCP2 to identify its targets, particularly the genes recognized by MeCP2 and associated with several neurological disorders. MeCP2 regulates gene expression in neurons, immune cells and during development by modulating various mechanisms and pathways. Dysregulation of the MeCP2 signaling pathway has been associated with several disorders, including neurological and autoimmune diseases. A thorough understanding of the molecular mechanisms underlying MeCP2 function can provide new therapeutic strategies for these conditions. The nervous system is the primary system affected in MeCP2-associated disorders, and other systems may also contribute to MeCP2 action through its target genes. MeCP2 signaling pathways provide promise as potential therapeutic targets in progressive MS and NMOSD. MeCP2 not only increases susceptibility and induces anti-inflammatory responses in immune sites but also leads to a chronic increase in pro-inflammatory cytokines gene expression (IFN-γ, TNF-α, and IL-1β) and downregulates the genes involved in immune regulation (IL-10, FoxP3, and CX3CR1). MeCP2 may modulate similar mechanisms in different pathologies and suggest that treatments for MS and NMOSD disorders may be effective in treating related disorders. MeCP2 regulates gene expression in MS and NMOSD. However, dysregulation of the MeCP2 signaling pathway is implicated in these disorders. MeCP2 plays a role as a therapeutic target for MS and NMOSD and provides pathways and mechanisms that are modulated by MeCP2 in the regulation of gene expression.

Evaluation of Rosuvastatin Therapy on SIRT1 Gene Expression in Patients with Multiple Sclerosis: An Uncontrolled Clinical Trial

Background

Multiple sclerosis (MS) is a chronic autoimmune disease. Current medications have some limitations such as low efficacy and high side effects. In recent years, statins have been raised as potential therapeutics for MS treatment with minimal complications. In addition, patient monitoring using suitable molecular markers is necessary for treatment response evaluation.

Objective

The aim of the present study was the evaluation of SIRT1 gene expression changes following rosuvastatin therapy in patients with MS.

Methods

This before-after uncontrolled clinical trial study was performed on 25 patients with MS. Patients were treated with 20 mg rosuvastatin daily for 3 months. The Expanded Disability Status Scale (EDSS) was measured before and after statin therapy. Blood samples were taken from patients 2 times, before and after statin therapy, and centrifuged for white blood cell isolation. Total RNA was extracted using RNX-plus reagent, and complementary DNA was synthesized using Pars Tous cDNA Synthesis Kit. Real-time polymerase chain reaction was done using SYBR blue master mix and gene-specific primers in Roche light cycler. Patients' information was recorded using a checklist. Data analysis was performed using SPSS version 23 and Graph Pad version 9 software and P < 0.05 was considered a significant level.

Results

SIRT1 was significantly upregulated in MS patients after statin therapy. Subsequently, EDSS of patients was decreased along with the increase in SIRT1 gene expression, although EDSS changes were not significant (P > 0.05). Pearson correlation test showed no significant relationship between EDSS and SIRT1 gene expression (P > 0.05). No significant relationship was observed between SIRT1 expression or EDSS levels with patients' age, sex, weight, height, and body mass index and administrated drugs (P > 0.05).

Conclusions

SIRT1 potentially is a sensitive and reliable biomarker for patients with MS monitoring during statin therapy.

Sirtuin family in autoimmune diseases

In recent years, epigenetic modifications have been widely researched. As humans age, environmental and genetic factors may drive inflammation and immune responses by influencing the epigenome, which can lead to abnormal autoimmune responses in the body. Currently, an increasing number of studies have emphasized the important role of epigenetic modification in the progression of autoimmune diseases. Sirtuins (SIRTs) are class III nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases and SIRT-mediated deacetylation is an important epigenetic alteration. The SIRT family comprises seven protein members (namely, SIRT1-7). While the catalytic core domain contains amino acid residues that have remained stable throughout the entire evolutionary process, the N- and C-terminal regions are structurally divergent and contribute to differences in subcellular localization, enzymatic activity and substrate specificity. SIRT1 and SIRT2 are localized in the nucleus and cytoplasm. SIRT3, SIRT4, and SIRT5 are mitochondrial, and SIRT6 and SIRT7 are predominantly found in the nucleus. SIRTs are key regulators of various physiological processes such as cellular differentiation, apoptosis, metabolism, ageing, immune response, oxidative stress, and mitochondrial function. We discuss the association between SIRTs and common autoimmune diseases to facilitate the development of more effective therapeutic strategies.

Neurobehavioral, biochemical and histological assessment of the effects of resveratrol on cuprizone-induced demyelination in mice: role of autophagy modulation

Resveratrol is known to exhibit neuroprotective effects in many neurological disorders via autophagy modulation. However, controversial results have been reported about the therapeutic potential of resveratrol and the implication of autophagy in demyelinating diseases. This study aimed to evaluate the autophagic changes in cuprizone-intoxicated C57Bl/6 mice and explore the effect of autophagy activation by resveratrol on the demyelination and remyelination processes. Mice were fed with chow containing 0.2% cuprizone for 5 weeks, followed by a cuprizone-free diet for 2 weeks. Resveratrol (250 mg/kg/day) and/or chloroquine (an autophagy inhibitor; 10 mg/kg/day) were given for 5 weeks starting from the third week. At the end of the experiment, animals were tested on rotarod and then sacrificed for biochemical assessment, luxol fast blue (LFB) staining, and transmission electron microscopy (TEM) imaging of the corpus callosum. We observed that cuprizone-induced demyelination was associated with impaired degradation of autophagic cargo, induction of apoptosis, and manifest neurobehavioral disturbances. Oral treatment with resveratrol promoted motor coordination and improved remyelination with regular compacted myelin in most axons without a significant impact on myelin basic protein (MBP) mRNA expression. These effects are mediated, at least in part, via activating autophagic pathways that may involve SIRT1/FoxO1 activation. This study verified that resveratrol dampens cuprizone-induced demyelination, and partially enhances myelin repair through modulation of the autophagic flux, since interruption of the autophagic machinery by chloroquine reversed the therapeutic potential of resveratrol.

Immunomodulatory therapy with glatiramer acetate reduces endoplasmic reticulum stress and mitochondrial dysfunction in experimental autoimmune encephalomyelitis

Endoplasmic reticulum (ER) stress and mitochondrial dysfunction are found in lesions of multiple sclerosis (MS) and animal models of MS such as experimental autoimmune encephalomyelitis (EAE), and may contribute to the neuronal loss that underlies permanent impairment. We investigated whether glatiramer acetate (GA) can reduce these changes in the spinal cords of chronic EAE mice by using routine histology, immunostaining, and electron microscopy. EAE spinal cord tissue exhibited increased inflammation, demyelination, mitochondrial dysfunction, ER stress, downregulation of NAD+ dependent pathways, and increased neuronal death. GA reversed these pathological changes, suggesting that immunomodulating therapy can indirectly induce neuroprotective effects in the CNS by mediating ER stress.

Modulation of salivary ICAM-1 and SIRT1 by disease modifying drugs in undepressed relapsing-remitting multiple sclerosis patients

BACKGROUND

The pathophysiology of Multiple Sclerosis (MS) is multifactorial where the correlation between inflammation and MS is evident. Adhesion molecules such as Intercellular adhesion molecule-1 (ICAM-1) are implicated in MS. SIRT1 is a member of surtins family that play a protective role in neurodegenerative and inflammatory diseases. Although previously studied in Relapsing-Remitting Multiple Sclerosis (RRMS) patients, however the salivary expression of ICAM-1 and SIRT1 have not been yet studied in patients receiving fingolimod or interferon-β. Therefore, the present research aimed to investigate the expression of salivary ICAM-1 and SIRT1 in RRMS patients treated with fingolimod or interferon-β compared to controls.

METHODS

RRMS patients attending the neurology department of AL-Bashir Hospital were recruited. Patients' demographics, clinical information, and psychiatric status were evaluated (depression, anxiety and stress). Afterward, matched controls were recruited, then unstimulated whole saliva was obtained from the participants. The salivary expression of ICAM-1 and SIRT1 was investigated using western blot and normalized with β-actin.

RESULTS

Data were analyzed from 53 participants: 26 on fingolimod, 14 on interferon-β, and 13 control. The interferon-β treated patients showed a significantly (p < 0.001) higher ICAM-1 expression and lower SIRT1 expression (p < 0.05) compared to the control. Levels of ICAM-1 and SIRT1 did not vary between fingolimod and control.

CONCLUSION

ICAM-1 and SIRT1 expression might be affected with fingolimod or INF- β treatment which should be investigated more in the future.

Impact of histone modifier-induced protection against autoimmune encephalomyelitis on multiple sclerosis treatment

Multiple sclerosis is a progressive demyelinating central nervous system disorder with unknown etiology. The condition has heterogeneous presentations, including relapsing-remitting multiple sclerosis and secondary and primary progressive multiple sclerosis. The genetic and epigenetic mechanisms underlying these various forms of multiple sclerosis remain elusive. Many disease-modifying therapies approved for multiple sclerosis are broad-spectrum immunomodulatory drugs that reduce relapses but do not halt the disease progression or neuroaxonal damage. Some are also associated with many severe side effects, including fatalities. Improvements in disease-modifying treatments especially for primary progressive multiple sclerosis remain an unmet need. Several experimental animal models are available to decipher the mechanisms involved in multiple sclerosis. These models help us decipher the advantages and limitations of novel disease-modifying therapies for multiple sclerosis.

Role of Sirtuins in Physiology and Diseases of the Central Nervous System

Silent information regulators, sirtuins (SIRTs), are a family of enzymes which take part in major posttranslational modifications of proteins and contribute to multiple cellular processes, including metabolic and energetic transformations, as well as regulation of the cell cycle. Recently, SIRTs have gained increased attention as the object of research because of their multidirectional activity and possible role in the complex pathomechanisms underlying human diseases. The aim of this study was to review a current literature evidence of SIRTs' role in the physiology and pathology of the central nervous system (CNS). SIRTs have been demonstrated to be crucial players in the crosstalk between neuroinflammation, neurodegeneration, and metabolic alterations. The elucidation of SIRTs' role in the background of various CNS diseases offers a chance to define relevant markers of their progression and promising candidates for novel therapeutic targets. Possible diagnostic and therapeutic implications from SIRTs-related investigations are discussed, as well as their future directions and associated challenges.

Role of Ketogenic Diets in Multiple Sclerosis and Related Animal Models: An Updated Review

Prescribing a ketogenic diet (KD) is a century-old dietary intervention mainly used in the context of intractable epilepsy. The classic KD and its variants regained popularity in recent decades, and they are considered potentially beneficial in a variety of neurological conditions other than epilepsy. Many patients with multiple sclerosis (MS) have attempted diet modification for better control of their disease, although evidence thus far remains insufficient to recommend a specific diet for these patients. The results of 3 pilot clinical trials of KD therapy for MS, as well as several related studies, have been reported in recent years. The preliminary findings suggest that KD is safe, feasible, and potentially neuroprotective and disease-modifying for patients with MS. Research on corresponding rodent models has also lent support to the efficacy of KD in the prevention and treatment of experimental autoimmune encephalomyelitis and toxin-induced inflammatory demyelinating conditions in the brain. Furthermore, the animal studies have yielded mechanistic insights into the molecular mechanisms of KD action in relevant situations, paving the way for precision nutrition. Herein we review and synthesize recent advances and also identify unresolved issues, such as the roles of adipokines and gut microbiota, in this field. Hopefully this panoramic view of current understanding can inform future research directions and clinical practice with regard to KD in MS and related conditions.

Neuroprotective Potential of Dendritic Cells and Sirtuins in Multiple Sclerosis

Myeloid cells, including parenchymal microglia, perivascular and meningeal macrophages, and dendritic cells (DCs), are present in the central nervous system (CNS) and establish an intricate relationship with other cells, playing a crucial role both in health and in neurological diseases. In this context, DCs are critical to orchestrating the immune response linking the innate and adaptive immune systems. Under steady-state conditions, DCs patrol the CNS, sampling their local environment and acting as sentinels. During neuroinflammation, the resulting activation of DCs is a critical step that drives the inflammatory response or the resolution of inflammation with the participation of different cell types of the immune system (macrophages, mast cells, T and B lymphocytes), resident cells of the CNS and soluble factors. Although the importance of DCs is clearly recognized, their exact function in CNS disease is still debated. In this review, we will discuss modern concepts of DC biology in steady-state and during autoimmune neuroinflammation. Here, we will also address some key aspects involving DCs in CNS patrolling, highlighting the neuroprotective nature of DCs and emphasizing their therapeutic potential for the treatment of neurological conditions. Recently, inhibition of the NAD⁺-dependent deac(et)ylase sirtuin 6 was demonstrated to delay the onset of experimental autoimmune encephalomyelitis, by dampening DC trafficking towards inflamed LNs. Thus, a special focus will be dedicated to sirtuins’ role in DCs functions.

Therapeutic approaches targeting CD95L/CD95 signaling in cancer and autoimmune diseases

Cell death plays a pivotal role in the maintenance of tissue homeostasis. Key players in the controlled induction of cell death are the Death Receptors (DR). CD95 is a prototypic DR activated by its cognate ligand CD95L triggering programmed cell death. As a consequence, alterations in the CD95/CD95L pathway have been involved in several disease conditions ranging from autoimmune diseases to inflammation and cancer. CD95L-induced cell death has multiple roles in the immune response since it constitutes one of the mechanisms by which cytotoxic lymphocytes kill their targets, but it is also involved in the process of turning off the immune response. Furthermore, beyond the canonical pro-death signals, CD95L, which can be membrane-bound or soluble, also induces non-apoptotic signaling that contributes to its tumor-promoting and pro-inflammatory roles. The intent of this review is to describe the role of CD95/CD95L in the pathophysiology of cancers, autoimmune diseases and chronic inflammation and to discuss recently patented and emerging therapeutic strategies that exploit/block the CD95/CD95L system in these diseases.

SIRT1: A Potential Therapeutic Target in Autoimmune Diseases

The morbidity and mortality of autoimmune diseases (Ads) have been increasing worldwide, and the identification of novel therapeutic strategies for prevention and treatment is urgently needed. Sirtuin 1 (SIRT1), a member of the class III family of nicotinamide adenine dinucleotide (NAD⁺)-dependent histone deacetylases, has been reported to participate in the progression of several diseases. SIRT1 also regulates inflammation, oxidative stress, mitochondrial function, immune responses, cellular differentiation, proliferation and metabolism, and its altered functions are likely involved in Ads. Several inhibitors and activators have been shown to affect the development of Ads. SIRT1 may represent a novel therapeutic target in these diseases, and small molecules or natural products that modulate the functions of SIRT1 are potential therapeutic agents. In the present review, we summarize current studies of the biological functions of SIRT1 and its role in the pathogenesis and treatment of Ads.

Chronic Neurological Disorders: Genetic and Epigenetic Markers for Monitoring of Pharmacotherapy

Introduction

Chronic neurological diseases are a major cause of mortality and morbidity in the world. With increasing life expectancy in the developing world, the incidence and prevalence of these diseases are predicted to rise even further. This has also contributed to an increase in disability-adjusted life years (DALYs) for noncommunicable diseases. Treatment for such diseases also poses a challenge with multiple genetic and epigenetic factors leading to a varied outcome. Personalization of treatment is one way that treatment outcome/prognosis of disease can be improved, and pharmacogenomics plays a significant role in this context.

Methodology

This article reviewed the evidence pertaining to the association of genetic and epigenetic markers with major neurological disorders like multiple sclerosis (MS), Alzheimer's disease (AD), and Parkinson's disease (PD), which are a major source of burden among neurological disorders. Types of studies included are peer-reviewed original research articles from the PubMed database (1999-2018).

Results

This study compiled data regarding specific genetic and epigenetic markers with a significant correlation between the clinical diagnosis of the disease and prognosis of therapy from 65 studies. In a single platform, this review highlights the clues to some vital questions, such as why interferon beta (IFN-β) therapy fails to improve symptoms in all MS patients? why cholinesterase inhibitors fail to improve cognitive impairment in a subset of people suffering from AD? or why some individuals on levodopa (L-DOPA) for PD suffer from side-effects ranging from dyskinesia to hallucination while others do not?

Conclusion

This article summarizes the genetic and epigenetic factors that may either require monitoring or help in deciding future pharmacotherapy in a patient suffering from MS, AD, and PD. As the health care system develops and reaches newer heights, we expect more and more of these biomarkers to be used as pharmacotherapeutic outcome indicators.

Multiple Sclerosis Biomarker Discoveries by Proteomics and Metabolomics Approaches

Multiple sclerosis (MS) is an autoimmune inflammatory disorder of the central nervous system (CNS) resulting in demyelination and axonal loss in the brain and spinal cord. The precise pathogenesis and etiology of this complex disease are still a mystery. Despite many studies that have been aimed to identify biomarkers, no protein marker has yet been approved for MS. There is urgently needed for biomarkers, which could clarify pathology, monitor disease progression, response to treatment, and prognosis in MS. Proteomics and metabolomics analysis are powerful tools to identify putative and novel candidate biomarkers. Different human compartments analysis using proteomics, metabolomics, and bioinformatics approaches has generated new information for further clarification of MS pathology, elucidating the mechanisms of the disease, finding new targets, and monitoring treatment response. Overall, omics approaches can develop different therapeutic and diagnostic aspects of complex disorders such as multiple sclerosis, from biomarker discovery to personalized medicine.

Trpv4 regulates Nlrp3 inflammasome via SIRT1/PGC-1α pathway in a cuprizone-induced mouse model of demyelination

Increasing evidence has demonstrated that the Nod-like receptor pyrin domain containing 3 (Nlrp3) inflammasome overactivated during demyelinating disorders. It has been implicated that transient receptor potential type 4 (Trpv4) is regarded as a polymodal ionotropic receptor that plays an important role in a multitude of pathological conditions, including inflammation. The aim of this study was to investigate whether the Trpv4 channel regulates Nlrp3 inflammasome in the corpus callosum of mice with demyelination. Our results showed that CPZ treatment significantly increased the expression of Trpv4, activated Nlrp3 inflammasome, reduced peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) and decreased mitochondrial function. siRNA-mediated Nlrp3 knockdown inhibited glial activation and alleviated demyelination. Whereas knockdown of Trpv4 by siRNA markedly ameliorated Nlrp3 inflammasome activation and restored mitochondrial function as well as reducing the level of reactive oxygen species (ROS). Meanwhile, glial activation, demyelination and behavioral impairment induced by CPZ were also alleviated by siRNA-mediated Trpv4 knockdown. Furthermore, immunoprecipitation and use of a lysine acetylation assay showed that Sirtuin1 (SIRT1) mediated the PGC-1α deacetylation, which is involved in Nlrp3 inflammasome activation. These findings suggest that Trpv4 regulates mitochondrial function through the SIRT1/PGC-1α pathway, which further trigger Nlrp3 inflammasome activation in the CPZ-induced demyelination in mice.

Calorie restriction promotes remyelination in a Cuprizone-Induced demyelination mouse model of multiple sclerosis

Over the past few decades several attempts have been made to introduce a potential and promising therapy for Multiple sclerosis (MS). Calorie restriction (CR) is a dietary manipulation to reduce calorie intake which has been shown to improve neuroprotection and attenuate neurodegenerative disorders. Here, we evaluated the effect of 33% CR regimen for 4 weeks on the remyelination capacity of Cuprizone (CPZ) induced demyelination in a mouse model of MS. Results showed that CR induced a significant increase in motor coordination and balance performance in CPZ mice. Also, luxol fast blue (LFB) staining showed that CR regimen significantly improved the remyelination in the corpus callosum of CPZ + CR mice compared to the CPZ group. In addition, CR regimen significantly increased the transcript expression levels of BDNF, Sox2, and Sirt1 in the corpus callosum of CPZ mice, while decreasing the p53 levels. Moreover, CR regimen significantly decreased the apoptosis rate. Furthermore, astrogliosis (GFAP + astrocytes) and microgliosis (Iba-1 + microglia) were significantly decreased by CR regimen while oligodendrogenesis (Olig2+) and Sirt1 + cell expression were significantly increased in the corpus callosum of CPZ + CR mice compared to the CPZ group. In conclusion, CR regimen can promote remyelination potential in a CPZ-demyelinating mouse model of MS by increasing oligodendrocyte generation while decreasing their apoptosis.

The emerging role of lncRNAs in multiple sclerosis

Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system (CNS) with various clinical manifestations. The characteristic of MS is that myelin is attacked by the body's immune system and increases the electrical capacity of axons, and is the primary pathophysiological mechanism of the transmission block. Studies have shown that epigenetic factors participate in the development of MS. LncRNAs are highly abundant and heterogeneous linear RNA transcripts with lengths exceeding 200 nucleotides and no protein-coding potential. Currently, pieces of evidence have demonstrated that lncRNAs have fundamental actions in multiple cellular pathways, including immune system regulation, epithelial-mesenchymal transition (EMT), cancer cell growth and metastasis, cellular homeostasis, and embryo development. It has been demonstrated that epigenetic mechanisms have an abundant role in the pathogenesis of MS in which the role of lncRNAs as epigenetic regulatory molecules in molecular processes has been proven. In this paper, we have focused on the correlation between MS and lncRNAs, the role of lncRNA in the pathogenesis of the disease, and the diagnostic and prognostic potential of lncRNA in MS.

Histone deacetylases as targets in autoimmune and autoinflammatory diseases

Reversible lysine acetylation of histones is a key epigenetic regulatory process controlling gene expression. Reversible histone acetylation is mediated by two opposing enzyme families: histone acetyltransferases (HATs) and histone deacetylases (HDACs). Moreover, many non-histone targets of HATs and HDACs are known, suggesting a crucial role for lysine acetylation as a posttranslational modification on the cellular proteome and protein function far beyond chromatin-mediated gene regulation. The HDAC family consists of 18 members and pan-HDAC inhibitors (HDACi) are clinically used for the treatment of certain types of cancer. HDACi or individual HDAC member-deficient (cell lineage-specific) mice have also been tested in a large number of preclinical mouse models for several autoimmune and autoinflammatory diseases and in most cases HDACi treatment results in an attenuation of clinical disease severity. A reduction of disease severity has also been observed in mice lacking certain HDAC members. This indicates a high therapeutic potential of isoform-selective HDACi for immune-mediated diseases. Isoform-selective HDACi and thus targeted inactivation of HDAC isoforms might also overcome the adverse effects of current clinically approved pan-HDACi. This review provides a brief overview about the fundamental function of HDACs as epigenetic regulators, highlights the roles of HDACs beyond chromatin-mediated control of gene expression and summarizes the studies showing the impact of HDAC inhibitors and genetic deficiencies of HDAC members for the outcome of autoimmune and autoinflammatory diseases with a focus on rheumatoid arthritis, inflammatory bowel disease and experimental autoimmune encephalomyelitis (EAE) as an animal model of multiple sclerosis.

Epigenetics in Multiple Sclerosis

Multiple sclerosis (MS) is an aggravating autoimmune disease that cripples young patients slowly with physical, sensory and cognitive deficits. The break of self-tolerance to neuronal antigens is the key to the pathogenesis of MS, with autoreactive T cells causing demyelination that subsequently leads to inflammation-mediated neurodegenerative events in the central nervous system. The exact etiology of MS remains elusive; however, the interplay of genetic and environmental factors contributes to disease development and progression. Given that genetic variation only accounts for a fraction of risk for MS, extrinsic risk factors including smoking, infection and lack of vitamin D or sunshine, which cause changes in gene expression, contribute to disease development through epigenetic regulation. To date, there is a growing body of scientific evidence to support the important roles of epigenetic processes in MS. In this chapter, the three main layers of epigenetic regulatory mechanisms, namely DNA methylation, histone modification and microRNA-mediated gene regulation, will be discussed, with a particular focus on the role of epigenetics on dysregulated immune responses and neurodegenerative events in MS. Also, the potential for epigenetic modifiers as biomarkers and therapeutics for MS will be reviewed.

Epigenetic insights into multiple sclerosis disease progression

Multiple sclerosis (MS), a chronic inflammatory demyelinating and neurodegenerative disease of the central nervous system, is today a leading cause of unpredictable lifelong disability in young adults. The treatment of patients in progressive stages remains highly challenging, alluding to our limited understanding of the underlying pathological processes. In this review, we provide insights into the mechanisms underpinning MS progression from a perspective of epigenetics, that refers to stable and mitotically heritable, yet reversible, changes in the genome activity and gene expression. We first recapitulate findings from epigenetic studies examining the brain tissue of progressive MS patients, which support a contribution of DNA and histone modifications in impaired oligodendrocyte differentiation, defective myelination/remyelination and sustained neuro-axonal vulnerability. We next explore possibilities for identifying factors affecting progression using easily accessible tissues such as blood by comparing epigenetic signatures in peripheral immune cells and brain tissue. Despite minor overlap at individual methylation sites, nearly 30% of altered genes reported in peripheral immune cells of progressive MS patients were found in brain tissue, jointly converging on alterations of neuronal functions. We further speculate about the mechanisms underlying shared epigenetic patterns between blood and brain, which likely imply the influence of internal (genetic control) and/or external (e.g. smoking and ageing) factors imprinting a common signature in both compartments. Overall, we propose that epigenetics might shed light on clinically relevant mechanisms involved in disease progression and open new avenues for the treatment of progressive MS patients in the future.

Histone Deacetylase SIRT1 Mediates C5b-9-Induced Cell Cycle in Oligodendrocytes

Sublytic levels of C5b-9 increase the survival of oligodendrocytes (OLGs) and induce the cell cycle. We have previously observed that SIRT1 co-localizes with surviving OLGs in multiple sclerosis (MS) plaques, but it is not yet known whether SIRT1 is involved in OLGs survival after exposure to sublytic C5b-9. We have now investigated the role of SIRT1 in OLGs differentiation and the effect of sublytic levels of C5b-9 on SIRT1 and phosphorylated-SIRT1 (Ser27) expression. We also examined the downstream effects of SIRT1 by measuring histone H3 lysine 9 trimethylation (H3K9me3) and the expression of cyclin D1 as a marker of cell cycle activation. OLG progenitor cells (OPCs) purified from the brain of rat pups were differentiated in vitro and treated with sublytic C5b-9 or C5b6. To investigate the signaling pathway activated by C5b-9 and required for SIRT1 expression, we pretreated OLGs with a c-jun antisense oligonucleotide, a phosphoinositide 3-kinase (PI3K) inhibitor (LY294002), and a protein kinase C (PKC) inhibitor (H7). Our data show a significant reduction in phospho-SIRT1 and SIRT1 expression during OPCs differentiation, associated with a decrease in H3K9me3 and a peak of cyclin D1 expression in the first 24 h. Stimulation of OLGs with sublytic C5b-9 resulted in an increase in the expression of SIRT1 and phospho-SIRT1, H3K9me3, cyclin D1 and decreased expression of myelin-specific genes. C5b-9-stimulated SIRT1 expression was significantly reduced after pretreatment with c-jun antisense oligonucleotide, H7 or LY294002. Inhibition of SIRT1 with sirtinol also abolished C5b-9-induced DNA synthesis. Taken together, these data show that induction of SIRT1 expression by C5b-9 is required for cell cycle activation and is mediated through multiple signaling pathways.

RGC-32 regulates reactive astrocytosis and extracellular matrix deposition in experimental autoimmune encephalomyelitis

Extracellular matrix (ECM) deposition in active demyelinating multiple sclerosis (MS) lesions may impede axonal regeneration and can modify immune reactions. Response gene to complement (RGC)-32 plays an important role in the mediation of TGF-β downstream effects, but its role in gliosis has not been investigated. To gain more insight into the role played by RGC-32 in gliosis, we investigated its involvement in TGF-β-induced ECM expression and the upregulation of the reactive astrocyte markers α-smooth muscle actin (α-SMA) and nestin. In cultured neonatal rat astrocytes, collagens I, IV, and V, fibronectin, α-SMA, and nestin were significantly induced by TGF-β stimulation, and RGC-32 silencing resulted in a significant reduction in their expression. Using astrocytes isolated from RGC-32 knock-out (KO) mice, we found that the expression of TGF-β-induced collagens I, IV, and V, fibronectin, and α-SMA was significantly reduced in RGC-32 KO mice when compared with wild-type (WT) mice. SIS3 inhibition of Smad3 phosphorylation was also associated with a significant reduction in RGC-32 nuclear translocation and TGF-β-induced collagen I expression. In addition, during experimental autoimmune encephalomyelitis (EAE), RGC-32 KO mouse astrocytes displayed an elongated, bipolar phenotype, resembling immature astrocytes and glial progenitors whereas those from WT mice had a reactive, hypertrophied phenotype. Taken together, our data demonstrate that RGC-32 plays an important role in mediating TGF-β-induced reactive astrogliosis in EAE. Therefore, RGC-32 may represent a new target for therapeutic intervention in MS.

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.

LncRNAs, MALAT1 and lnc-DC as potential biomarkers for multiple sclerosis diagnosis

Long non-coding RNAs (lncRNAs) play an important role in gene regulation and show greater tissue specificity and complexity of biological functions. There is on-going research in their contribution in autoimmune diseases like multiple sclerosis (MS). Our study aimed at the evaluation of serum levels of lncRNAs, MALAT1 and lnc-DC in MS patients and the investigation of the association between these lncRNAs and the disease activity. Serum from 45 MS patients and 45 healthy controls was separated. MALAT1 and lnc-DC expression levels were assayed by qRT-PCR. MALAT1 and lnc-DC were significantly increased in MS patients (P=0.004 and P=0.006, respectively) in comparison with controls. There was a significant increase in expression of MALAT1 in secondary progressive MS (SPMS) subgroup compared with controls (P<0.0001); however, significant elevation of lnc-DC was demonstrated in relapsing remitting MS (RRMS) subtype (P=0.003) compared with normal controls. A positive association between the expression levels of MALAT1 and lnc-DC (r = 0.513, P < 0.0001) in MS patients was detected. Moreover, positive correlation was observed between MALAT1and lnc-DC in RRMS (r = 0.569, P = 0.001). Serum levels of MALAT1 and lnc-DC may serve as potential novel molecular biomarkers for MS diagnosis and may provide a new direction for its treatment.

Exploiting the Therapeutic Potential of Endogenous Immunomodulatory Systems in Multiple Sclerosis-Special Focus on the Peroxisome Proliferator-Activated Receptors (PPARs) and the Kynurenines

Multiple sclerosis (MS) is a progressive neurodegenerative disease, characterized by autoimmune central nervous system (CNS) demyelination attributable to a disturbed balance between encephalitic T helper 1 (Th1) and T helper 17 (Th17) and immunomodulatory regulatory T cell (Treg) and T helper 2 (Th2) cells, and an alternatively activated macrophage (M2) excess. Endogenous molecular systems regulating these inflammatory processes have recently been investigated to identify molecules that can potentially influence the course of the disease. These include the peroxisome proliferator-activated receptors (PPARs), PPARγ coactivator-1alpha (PGC-1α), and kynurenine pathway metabolites. Although all PPARs ameliorate experimental autoimmune encephalomyelitis (EAE), recent evidence suggests that PPARα, PPARβ/δ agonists have less pronounced immunomodulatory effects and, along with PGC-1α, are not biomarkers of neuroinflammation in contrast to PPARγ. Small clinical trials with PPARγ agonists have been published with positive results. Proposed as immunomodulatory and neuroprotective, the therapeutic use of PGC-1α activation needs to be assessed in EAE/MS. The activation of indolamine 2,3-dioxygenase (IDO), the rate-limiting step of the kynurenine pathway of tryptophan (Trp) metabolism, plays crucial immunomodulatory roles. Indeed, Trp metabolites have therapeutic relevance in EAE and drugs with structural analogy to kynurenines, such as teriflunomide, are already approved for MS. Further studies are required to gain deeper knowledge of such endogenous immunomodulatory pathways with potential therapeutic implications in MS.

Sirtuins in Neuroendocrine Regulation and Neurological Diseases

Silent information regulator 1 (SIRT1) is a mammalian homolog of the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase sirtuin family. Sirtuin was originally studied as the lifespan-extending gene, silent information regulator 2 (SIRT2) in budding yeast. There are seven mammalian homologs of sirtuin (SIRT1–7), and SIRT1 is the closest homolog to SIRT2. SIRT1 modulates various key targets via deacetylation. In addition to histones, these targets include transcription factors, such as forkhead box O (FOXO), Ku70, p53, NF-κB, PPAR-gamma co-activator 1-alpha (PGC-1α), and peroxisome proliferator-activated receptor γ (PPARγ). SIRT1 has many biological functions, including aging, cell survival, differentiation, and metabolism. Genetic and physiological analyses in animal models have shown beneficial roles for SIRT1 in the brain during both development and adulthood. Evidence from in vivo and in vitro studies have revealed that SIRT1 regulates the cellular fate of neural progenitors, axon elongation, dendritic branching, synaptic plasticity, and endocrine function. In addition to its importance in physiological processes, SIRT1 has also been implicated in protection of neurons from degeneration in models of neurological diseases, such as traumatic brain injury and Alzheimer’s disease. In this review, we focus on the role of SIRT1 in the neuroendocrine system and neurodegenerative diseases. We also discuss the potential therapeutic implications of targeting the sirtuin pathway.

Loss of HDAC11 ameliorates clinical symptoms in a multiple sclerosis mouse model

In an animal model for multiple sclerosis, the absence of HDAC11 reduces clinical severity, spinal cord demyelination, and immune cell infiltration, suggesting that HDAC11 is a promising target for MS treatment.

Multiple sclerosis (MS) is a chronic, immune-mediated, demyelinating disease of the central nervous system (CNS). There is no known cure for MS, and currently available drugs for managing this disease are only effective early on and have many adverse side effects. Results from recent studies suggest that histone deacetylase (HDAC) inhibitors may be useful for the treatment of autoimmune and inflammatory diseases such as MS. However, the underlying mechanisms by which HDACs influence immune-mediated diseases such as MS are unclear. More importantly, the question of which specific HDAC(s) are suitable drug targets for the potential treatment of MS remains unanswered. Here, we investigate the functional role of HDAC11 in experimental autoimmune encephalomyelitis, a mouse model for MS. Our results indicate that the loss of HDAC11 in KO mice significantly reduces clinical severity and demyelination of the spinal cord in the post-acute phase of experimental autoimmune encephalomyelitis. The absence of HDAC11 leads to reduced immune cell infiltration into the CNS and decreased monocytes and myeloid DCs in the chronic progressive phase of the disease. Mechanistically, HDAC11 controls the expression of the pro-inflammatory chemokine C–C motif ligand 2 (CCL2) gene by enabling the binding of PU.1 transcription factor to the CCL2 promoter. Our results reveal a novel pathophysiological function for HDAC11 in CNS demyelinating diseases, and warrant further investigations into the potential use of HDAC11-specific inhibitors for the treatment of chronic progressive MS.

Do Human Endogenous Retroviruses Contribute to Multiple Sclerosis, and if So, How?

The gammaretroviral human endogenous retrovirus (HERV) families MRSV/HERV-W and HERV-H (including the closely related HERV-Fc1) are associated with an increased risk of multiple sclerosis (MS). Complete HERV sequences betray their endogenous retroviral origin, with open reading frames in gag, pro, pol and env being flanked by two long terminal repeats containing promoter and enhancer sequences with the capacity to regulate HERV transactivation and the activity of host genes in spite of endogenous epigenetic repression mechanisms. HERV virions, RNA, cDNA, Gag and Env, and antibodies to HERV transcriptional products, have variously been found in the blood and/or brain and/or cerebrospinal fluid of MS patients, with the HERV expression level being associated with disease status. Furthermore, some HERV-associated single nucleotide polymorphisms (SNPs), such as rs662139 T/C in a 3-kb region of Xq22.3 containing a HERV-W env locus, and rs391745, upstream of the HERV-Fc1 locus on the X chromosome, are associated with MS susceptibility, while a negative association has been reported with SNPs in the tripartite motif-containing (TRIM) protein-encoding genes TRIM5 and TRIM22. Factors affecting HERV transcription include immune activation and inflammation, since HERV promoter regions possess binding sites for related transcription factors; oxidative stress, with oxidation of guanine to 8-oxoguanine and conversion of cytosine to 5-hydroxymethylcytosine preventing binding of methyl groups transferred by DNA methyltransferases; oxidative stress also inhibits the activity of deacetylases, thereby favouring the acetylation of histone lysine residues favouring gene expression; interferon beta; natalizumab treatment; impaired epigenetic regulation; and the sex of patients.

Epigenetic research in multiple sclerosis: progress, challenges, and opportunities

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system. MS likely results from a complex interplay between predisposing causal gene variants (the strongest influence coming from HLA class II locus) and environmental risk factors such as smoking, infectious mononucleosis, and lack of sun exposure/vitamin D. However, little is known about the mechanisms underlying MS development and progression. Moreover, the clinical heterogeneity and variable response to treatment represent additional challenges to a comprehensive understanding and efficient treatment of disease. Epigenetic processes, such as DNA methylation and histone posttranslational modifications, integrate influences from the genes and the environment to regulate gene expression accordingly. Studying epigenetic modifications, which are stable and reversible, may provide an alternative approach to better understand and manage disease. We here aim to review findings from epigenetic studies in MS and further discuss the challenges and clinical opportunities arising from epigenetic research, many of which apply to other diseases with similar complex etiology. A growing body of evidence supports a role of epigenetic processes in the mechanisms underlying immune pathogenesis and nervous system dysfunction in MS. However, disparities between studies shed light on the need to consider possible confounders and methodological limitations for a better interpretation of the data. Nevertheless, translational use of epigenetics might offer new opportunities in epigenetic-based diagnostics and therapeutic tools for a personalized care of MS patients.

Epigenetic Drugs for Multiple Sclerosis

There is increasing evidence that abnormalities in epigenetic mechanisms of gene expression contribute to the development of multiple sclerosis (MS). Advances in epigenetics have given rise to a new class of drugs, epigenetic drugs. Although many classes of epigenetic drugs are being investigated, at present most attention is being paid to two classes of epigenetic drugs: drugs that inhibit DNA methyltransferase (DNMTi) and drugs that inhibit histone deacetylase (HDACi). This paper discusses the potential use of epigenetic drugs in the treatment of MS, focusing on DNMTi and HDACi. Preclinical drug trials of DNMTi and HDACi for the treatment of MS are showing promising results. Epigenetic drugs could improve the clinical management of patients with MS.

SIRT1 and NAD+ precursors: Therapeutic targets in multiple sclerosis a review

Neurodegeneration is an important determinant of disability in multiple sclerosis (MS) but while currently approved treatments reduce inflammation, they have not been shown to reduce neurodegeneration. SIRT1, a NAD dependent protein deacetylase, has been implicated in the pathogenesis of neurodegeneration in neurological diseases including MS. We have studied the role of SIRT1 in experimental autoimmune encephalomyelitis (EAE) and found evidence for a neuroprotective role. In this review we summarize the most recent findings from the use of SIRT1 activators and SIRT1 overexpression in transgenic mice. These data support provide a rational for the use of SIRT1 activators in MS.

Mitochondrial function in hypoxic ischemic injury and influence of aging

Mitochondria are a major target in hypoxic/ischemic injury. Mitochondrial impairment increases with age leading to dysregulation of molecular pathways linked to mitochondria. The perturbation of mitochondrial homeostasis and cellular energetics worsens outcome following hypoxic-ischemic insults in elderly individuals. In response to acute injury conditions, cellular machinery relies on rapid adaptations by modulating posttranslational modifications. Therefore, post-translational regulation of molecular mediators such as hypoxia-inducible factor 1α (HIF-1α), peroxisome proliferator-activated receptor γ coactivator α (PGC-1α), c-MYC, SIRT1 and AMPK play a critical role in the control of the glycolytic-mitochondrial energy axis in response to hypoxic-ischemic conditions. The deficiency of oxygen and nutrients leads to decreased energetic reliance on mitochondria, promoting glycolysis. The combination of pseudohypoxia, declining autophagy, and dysregulation of stress responses with aging adds to impaired host response to hypoxic-ischemic injury. Furthermore, intermitochondrial signal propagation and tissue wide oscillations in mitochondrial metabolism in response to oxidative stress are emerging as vital to cellular energetics. Recently reported intercellular transport of mitochondria through tunneling nanotubes also play a role in the response to and treatments for ischemic injury. In this review we attempt to provide an overview of some of the molecular mechanisms and potential therapies involved in the alteration of cellular energetics with aging and injury with a neurobiological perspective.

Expression Profile of Long Noncoding RNAs in Peripheral Blood Mononuclear Cells from Multiple Sclerosis Patients

AIMS

Long noncoding RNAs (lncRNAs) play a key role in regulating immunological functions. Their impact on the chronic inflammatory disease multiple sclerosis (MS), however, remains unknown. We investigated the expression of lncRNAs in peripheral blood mononuclear cells (PBMCs) of patients with MS and attempt to explain their possible role in the process of MS.

METHODS

For this study, we recruited 26 patients with MS according to the revised McDonald criteria. Then, we randomly chose 6 patients for microarray analysis. Microarray assays identified outstanding differences in lncRNA expression, which were verified through real-time PCR. LncRNA functions were annotated for target genes using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and regulatory relationships between lncRNAs and target genes were analyzed using the "cis" and "trans" model.

RESULTS

There were 2353 upregulated lncRNAs, 389 downregulated lncRNAs, 1037 upregulated mRNAs, and 279 downregulated mRNAs in patients with MS compared to healthy control subjects (fold change >2.0). Real-time PCR results of six aberrant lncRNAs were consistent with the microarray data. The coexpression network comprised 864 lncRNAs and 628 mRNAs. Among differentially expressed lncRNAs, 10 lncRNAs were predicted to have 10 cis-regulated target genes, and 33 lncRNAs might regulate their trans target genes.

CONCLUSIONS

We identified a subset of dysregulated lncRNAs and mRNAs. The differentially expressed lncRNAs may be important in the process of MS. However, the specific molecular mechanisms and biological functions of these lncRNAs in the pathogenesis of MS need further study.

Role of SIRT1 in autoimmune demyelination and neurodegeneration

Multiple sclerosis (MS) is a demyelinating disease characterized by chronic inflammation of the central nervous system, in which many factors can act together to influence disease susceptibility and progression. SIRT1 is a member of the histone deacetylase class III family of proteins and is an NAD(+)-dependent histone and protein deacetylase. SIRT1 can induce chromatin silencing through the deacetylation of histones and plays an important role as a key regulator of a wide variety of cellular and physiological processes including DNA damage, cell survival, metabolism, aging, and neurodegeneration. It has gained a lot of attention recently because many studies in animal models of demyelinating and neurodegenerative diseases have shown that SIRT1 induction can ameliorate the course of the disease. SIRT1 expression was found to be decreased in the peripheral blood mononuclear cells of MS patients during relapses. SIRT1 represents a possible biomarker of relapses and a potential new target for therapeutic intervention in MS. Modulation of SIRT1 may be a valuable strategy for treating or preventing MS and neurodegenerative central nervous system disorders.

Histone hypoacetylation and increased histone deacetylases in peripheral blood mononuclear cells from patients with Graves' disease

The objective of this study was to investigate histone modification patterns in peripheral blood mononuclear cells (PBMCs) of patients with Graves' disease (GD). Thirty GD patients and 20 healthy controls were enrolled in this study. Global histone H3/H4 acetylation levels of PBMCs in all subjects were detected by enzyme-linked immunosorbent assay. mRNA levels of histone-related chromatin modifier genes were measured by real-time quantitative reverse transcription-polymerase chain reaction. Global histone H4 acetylation level in PBMCs of GD patients was significantly decreased compared with controls (p=0.005). The mRNA expression of histone deacetylases HDAC1 and HDAC2 were significantly increased in PBMCs of GD patients compared with controls (p=0.004 and 0.018; respectively). No significant difference was observed either in SIRT1 or in HATs mRNA including p300, CREBBP between GD patients and controls (p>0.05). Our findings firstly suggested that histone acetylation modifications are aberrant in PBMCs of GD patients, possibly due to the deregulation of epigenetic modifier genes.

Peripheral leukocyte expression of the potential biomarker proteins Bdnf, Sirt1, and Psen1 is not regulated by promoter methylation in Alzheimer's disease patients

The identification of Alzheimer's disease (AD) biomarkers is crucial to support drug discovery. Within putative biomarkers, peripheral Bdnf levels correlate with cognitive decline and AD, although conflicting findings are reported. Sirtuin 1 (Sirt1) serum levels are lower in AD patients and Presenilin 1 (Psen1) is expressed by blood cells. DNA methylation is altered in AD patients, suggesting that epigenetic mechanisms play a role in AD pathophysiology. The objective of this study was to investigate promoter methylation levels of potential biomarkers in AD cases and controls. Peripheral blood DNA methylation levels were analysed by methylation-specific primer real-time PCR. Bdnf promoter methylation levels did not differ between AD patients and controls. Similarly, Sirt1 promoter revealed minimal levels of methylation which did not display significant differences between groups. No significant difference was revealed between AD patients and controls also in Psen1 methylation, showing a large variability of values among subjects. Although peripheral Bdnf expression is associated with differential promoter methylation in psychiatric and neurological disorders, our results suggest that different mechanisms take place in AD. The finding that the control of Sirt1 protein levels in blood is not exerted through the repression of mRNA expression by promoter hypermethylation is in agreement with previous data. In contrast, other studies reported that Psen1 methylation may be increased or decreased in AD patients, suggesting that additional studies are required. In conclusion, this study shows that peripheral levels of the potential AD biomarker proteins Bdnf, Sirt1, and Psen1 are not regulated by different promoter methylation.