Epigenetic Regulatory Effect of Exercise on Glutathione Peroxidase 1 Expression in the Skeletal Muscle of Severely Dyslipidemic Mice

Star power: harnessing the reactive astrocyte response to promote remyelination in multiple sclerosis

Astrocytes are indispensable for central nervous system development and homeostasis. In response to injury and disease, astrocytes are integral to the immunological- and the, albeit limited, repair response. In this review, we will examine some of the functions reactive astrocytes play in the context of multiple sclerosis and related animal models. We will consider the heterogeneity or plasticity of astrocytes and the mechanisms by which they promote or mitigate demyelination. Finally, we will discuss a set of biomedical strategies that can stimulate astrocytes in their promyelinating response.

Immunoproteasome Inhibition Ameliorates Aged Dystrophic Mouse Muscle Environment

Muscle wasting is a major pathological feature observed in Duchenne muscular dystrophy (DMD) and is the result of the concerted effects of inflammation, oxidative stress and cell senescence. The inducible form of proteasome, or immunoproteasome (IP), is involved in all the above mentioned processes, regulating antigen presentation, cytokine production and immune cell response. IP inhibition has been previously shown to dampen the altered molecular, histological and functional features of 3-month-old mdx mice, the animal model for DMD. In this study, we described the role of ONX-0914, a selective inhibitor of the PSMB8 subunit of immunoproteasome, in ameliorating the pathological traits that could promote muscle wasting progression in older, 9-month-old mdx mice. ONX-0914 reduces the number of macrophages and effector memory T cells in muscle and spleen, while increasing the number of regulatory T cells. It modulates inflammatory markers both in skeletal and cardiac muscle, possibly counteracting heart remodeling and hypertrophy. Moreover, it buffers oxidative stress by improving mitochondrial efficiency. These changes ultimately lead to a marked decrease of fibrosis and, potentially, to more controlled myofiber degeneration/regeneration cycles. Therefore, ONX-0914 is a promising molecule that may slow down muscle mass loss, with relatively low side effects, in dystrophic patients with moderate to advanced disease.

Regulation of A-to-I RNA editing and stop codon recoding to control selenoprotein expression during skeletal myogenesis

Selenoprotein N (SELENON), a selenocysteine (Sec)-containing protein with high reductive activity, maintains redox homeostasis, thereby contributing to skeletal muscle differentiation and function. Loss-of-function mutations in SELENON cause severe neuromuscular disorders. In the early-to-middle stage of myoblast differentiation, SELENON maintains redox homeostasis and modulates endoplasmic reticulum (ER) Ca2+ concentration, resulting in a gradual reduction from the middle-to-late stages due to unknown mechanisms. The present study describes post-transcriptional mechanisms that regulate SELENON expression during myoblast differentiation. Part of an Alu element in the second intron of SELENON pre-mRNA is frequently exonized during splicing, resulting in an aberrant mRNA that is degraded by nonsense-mediated mRNA decay (NMD). In the middle stage of myoblast differentiation, ADAR1-mediated A-to-I RNA editing occurs in the U1 snRNA binding site at 5' splice site, preventing Alu exonization and producing mature mRNA. In the middle-to-late stage of myoblast differentiation, the level of Sec-charged tRNASec decreases due to downregulation of essential recoding factors for Sec insertion, thereby generating a premature termination codon in SELENON mRNA, which is targeted by NMD.

Effects of Long-Term Regular Continuous and Intermittent Walking on Oxidative Stress, Metabolic Profile, Heart Rate Variability, and Blood Pressure in Older Adults with Hypertension

It is documented that regular exercise is beneficial for improving the antioxidant system, metabolic system, cardiac autonomic function, and blood pressure in those with hypertension. In this regard, low-intensity exercise is recommended for older adults, particularly those with chronic diseases. This study aimed to compare the effects of long-term regular continuous walking with intermittent walking on oxidative stress, metabolic profile, heart rate variability, and blood pressure in older adults with hypertension. Forty-three participants with hypertension aged 60–80 years were randomly divided into the continuous or intermittent walking (CON or INT) groups. Participants in the CON group walked for 30 min, 3 days/week for 12 weeks. Participants in the INT group split 30 min walking into 3 identical sessions punctuated by a 1 min rest after each session, 3 days/week for 12 weeks. Antioxidant and oxidative stress markers, metabolic markers, heart rate variability, and blood pressure were evaluated before and after the exercise program. Glutathione (GSH), GSH to GSH disulfide (GSSG) ratio, and total GSH increased significantly, and GSSG and malondialdehyde decreased significantly in both groups ( $p<0.05$ ) without significant differences between groups. Triglycerides, ratio of total cholesterol to high-density lipoprotein cholesterol, and atherosclerogenic index were significantly lower in the CON group than those in the INT group ( $p<0.05$ ). The standard deviation of the NN intervals and root mean square of the successive differences were significantly higher, and low-frequency power was significantly lower in the INT group than that in the CON group ( $p<0.05$ ). No significant changes in blood pressure were noted in both groups, and nor were there any significant differences between groups. Long-term regular continuous and intermittent walking may comparably increase antioxidants, reduce oxidative stress, and be beneficial for improving important blood pressure-related outcomes, including metabolic profile or cardiac autonomic function in older adults with hypertension.

Molecular Big Data in Sports Sciences: State-of-Art and Future Prospects of OMICS-Based Sports Sciences

Together with environment and experience (that is to say, diet and training), the biological and genetic make-up of an athlete plays a major role in exercise physiology. Sports genomics has shown, indeed, that some DNA single nucleotide polymorphisms (SNPs) can be associated with athlete performance and level (such as elite/world-class athletic status), having an impact on physical activity behavior, endurance, strength, power, speed, flexibility, energetic expenditure, neuromuscular coordination, metabolic and cardio-respiratory fitness, among others, as well as with psychological traits. Athletic phenotype is complex and depends on the combination of different traits and characteristics: as such, it requires a “complex science,” like that of metadata and multi-OMICS profiles. Several projects and trials (like ELITE, GAMES, Gene SMART, GENESIS, and POWERGENE) are aimed at discovering genomics-based biomarkers with an adequate predictive power. Sports genomics could enable to optimize and maximize physical performance, as well as it could predict the risk of sports-related injuries. Exercise has a profound impact on proteome too. Proteomics can assess both from a qualitative and quantitative point of view the modifications induced by training. Recently, scholars have assessed the epigenetics changes in athletes. Summarizing, the different omics specialties seem to converge in a unique approach, termed sportomics or athlomics and defined as a “holistic and top-down,” “non-hypothesis-driven research on an individual’s metabolite changes during sports and exercise” (the Athlome Project Consortium and the Santorini Declaration) Not only sportomics includes metabonomics/metabolomics, but relying on the athlete’s biological passport or profile, it would enable the systematic study of sports-induced changes and effects at any level (genome, transcriptome, proteome, etc.). However, the wealth of data is so huge and massive and heterogenous that new computational algorithms and protocols are needed, more computational power is required as well as new strategies for properly and effectively combining and integrating data.

The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms

Oxidative stress can be induced by various stimuli and altered in certain conditions, including exercise and pain. Although many studies have investigated oxidative stress in relation to either exercise or pain, the literature presents conflicting results. Therefore, this review critically discusses existing literature about this topic, aiming to provide a clear overview of known interactions between oxidative stress, exercise, and pain in healthy people as well as in people with chronic pain, and to highlight possible confounding factors to keep in mind when reflecting on these interactions. In addition, autonomic regulation and epigenetic mechanisms are proposed as potential mechanisms of action underlying the interplay between oxidative stress, exercise, and pain. This review highlights that the relation between oxidative stress, exercise, and pain is poorly understood and not straightforward, as it is dependent on the characteristics of exercise, but also on which population is investigated. To be able to compare studies on this topic, strict guidelines should be developed to limit the effect of several confounding factors. This way, the true interplay between oxidative stress, exercise, and pain, and the underlying mechanisms of action can be revealed and validated via independent studies.

Physical Exercise-Mediated Changes in Redox Profile Contribute to Muscle Remodeling After Passive Hand-Rolled Cornhusk Cigarette Smoke Exposure

Consumption of non-traditional cigarettes has increased considerably worldwide, and they can induce skeletal muscle dysfunction. Physical exercise has been demonstrated to be important for prevention and treatment of smoking-related diseases. Therfore, the aim of this study was to investigate the effects of combined physical exercise (aerobic plus resistance exercise) on muscle histoarchitecture and oxidative stress in the animals exposed chronically to smoke from hand-rolled cornhusk cigarette (HRCC). Male Swiss mice were exposed to ambient air or passively to the smoke of 12 cigarettes over three daily sessions (four cigarettes per session) for 30 consecutive days with or without combined physical training. 48 h after the last training session, total leukocyte count was measured in bronchoalveolar lavage fluid (BALF), and the quadriceps were removed for histological/immunohistochemical analysis and measurement of oxidative stress parameters. The effects of HRCC on the number of leukocytes in BALF, muscle fiber diameter, central nuclei, and nuclear factor kappa B (NF-κB) were reverted after combined physical training. In addition, increased myogenic factor 5, tumor necrosis factor alpha (TNFα), reduced transforming growth factor beta (TGF-β), and nitrate levels were observed after physical training. However, the reduction in superoxide dismutase and glutathione/glutathione oxidized ratio induced by HRCC was not affected by the training program. These results suggest the important changes in the skeletal muscle brought about by HRCC-induced alteration in the muscle redox profile. In addition, combined physical exercise contributes to remodeling without disrupting muscle morphology.

Regulatory Phenomena in the Glutathione Peroxidase Superfamily

Significance: The selenium-containing Glutathione peroxidases (GPxs)1-4 protect against oxidative challenge, inhibit inflammation and oxidant-induced regulated cell death. Recent Advances: GPx1 and GPx4 dampen phosphorylation cascades predominantly via prevention of inactivation of phosphatases by H₂O₂ or lipid hydroperoxides. GPx2 regulates the balance between regeneration and apoptotic cell shedding in the intestine. It inhibits inflammation-induced carcinogenesis in the gut but promotes growth of established cancers. GPx3 deficiency facilitates platelet aggregation likely via disinhibition of thromboxane biosynthesis. It is also considered a tumor suppressor. GPx4 is expressed in three different forms. The cytosolic form proved to inhibit interleukin-1-driven nuclear factor κB activation and leukotriene biosynthesis. Moreover, it is a key regulator of ferroptosis, because it reduces hydroperoxy groups of complex lipids and silences lipoxygenases. By alternate substrate use, the nuclear form contributes to chromatin compaction. Mitochondrial GPx4 forms the mitochondrial sheath of spermatozoa and, thus, guarantees male fertility. Out of the less characterized GPxs, the cysteine-containing GPx7 and GPx8 are unique in contributing to oxidative protein folding in the endoplasmic reticulum by reacting with protein isomerase as an alternate substrate. A yeast 2-Cysteine glutathione peroxidase equipped with CP and CR was reported to sense H₂O₂ for inducing an adaptive response. Critical Issues: Most of the findings compiled are derived from tissue culture and/or animal studies only. Their impact on human physiology is sometimes questionable. Future Directions: The expression of individual GPxs and GPx-dependent regulatory phenomena are to be further investigated, in particular in respect to human health.

Physical Exercise and Epigenetic Modifications in Skeletal Muscle

Physical activity and sports play major roles in the overall health status of humans. It is well known that regular exercise helps to lower the risk for a broad variety of health problems, such as cardiovascular disease, type 2 diabetes, and cancer. Being physically active induces a wide variety of molecular adaptations, for example fiber type switches or other metabolic alterations, in skeletal muscle tissue. These adaptations are based on exercise-induced changes to the skeletal muscle transcriptome. Understanding their nature is crucial to improve the development of exercise-based therapeutic strategies. Recent research indicates that specifically epigenetic mechanisms, i.e., pathways that induce changes in gene expression patterns without altering the DNA base sequence, might play a major role in controlling skeletal muscle transcriptional patterns. Epigenetic mechanisms include DNA and histone modifications, as well as expression of specific microRNAs. They can be modulated by environmental factors or external stimuli, such as exercise, and eventually induce specific and fine-tuned changes to the transcriptional response. In this review, we highlight current knowledge on epigenetic changes induced in exercising skeletal muscle, their target genes, and resulting phenotypic changes. In addition, we raise the question of whether epigenetic modifications might serve as markers for the design and management of optimized and individualized training protocols, as prognostic tools to predict training adaptation, or even as targets for the design of "exercise mimics".

Exercise, redox homeostasis and the epigenetic landscape

Physical exercise represents one of the strongest physiological stimuli capable to induce functional and structural modifications in all biological systems. Indeed, beside the traditional genetic mechanisms, physical exercise can modulate gene expression through epigenetic modifications, namely DNA methylation, post-translational histone modification and non-coding RNA transcripts.

Initially considered as merely damaging molecules, it is now well recognized that both reactive oxygen (ROS) and nitrogen species (RNS) produced under voluntary exercise play an important role as regulatory mediators in signaling processes. While robust scientific evidences highlight the role of exercise-associated redox modifications in modulating gene expression through the genetic machinery, the understanding of their specific impact on epigenomic profile is still at an early stage. This review will provide an overview of the role of ROS and RNS in modulating the epigenetic landscape in the context of exercise-related adaptations.

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Physical exercise can modulate gene expression through epigenetic modifications.

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Epigenetic regulation of ROS/RNS generating, sensing and neutralizing enzymes can impact the cellular levels of ROS and RNS.

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ROS might act as modulators of epigenetic machinery, interfering with DNA methylation, hPTMs and ncRNAs expression.

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Redox homeostasis might hold a relevant role in the epigenetic landscape modulating exercise-related adaptations.

Atherosclerosis is associated with a decrease in cerebral microvascular blood flow and tissue oxygenation

Chronic atherosclerosis may cause cerebral hypoperfusion and inadequate brain oxygenation, contributing to the progression of cognitive decline. In this study, we exploited two-photon phosphorescence lifetime microscopy to measure the absolute partial pressure of oxygen (PO₂) in cortical tissue in both young and old LDLR^-/-, hApoB100^+/+ mice, spontaneously developing atherosclerosis with age. Capillary red-blood-cell (RBC) speed, flux, hematocrit and capillary diameter were also measured by two-photon imaging of FITC-labelled blood plasma. Our results show positive correlations between RBC speed, flux, diameter and capillary-adjacent tissue PO₂. When compared to the young mice, we observed lower tissue PO₂, lower RBC speed and flux, and smaller capillary diameter in the old atherosclerotic mice. The old mice also exhibited a higher spatial heterogeneity of tissue PO₂, and RBC speed and flux, suggesting a less efficient oxygen extraction.

Blood-brain barrier permeability and physical exercise

In this narrative review, a theoretical framework on the crosstalk between physical exercise and blood-brain barrier (BBB) permeability is presented. We discuss the influence of physical activity on the factors affecting BBB permeability such as systemic inflammation, the brain renin-angiotensin and noradrenergic systems, central autonomic function and the kynurenine pathway. The positive role of exercise in multiple sclerosis and Alzheimer’s disease is described. Finally, the potential role of conditioning as well as the effect of exercise on BBB tight junctions is outlined. There is a body of evidence that regular physical exercise diminishes BBB permeability as it reinforces antioxidative capacity, reduces oxidative stress and has anti-inflammatory effects. It improves endothelial function and might increase the density of brain capillaries. Thus, physical training can be emphasised as a component of prevention programs developed for patients to minimise the risk of the onset of neuroinflammatory diseases as well as an augmentation of existing treatment. Unfortunately, despite a sound theoretical background, it remains unclear as to whether exercise training is effective in modulating BBB permeability in several specific diseases. Further research is needed as the impact of exercise is yet to be fully elucidated.

Role of glutathione peroxidase 1 in glucose and lipid metabolism-related diseases

Glutathione peroxidase 1 (GPX1) is a selenium-dependent enzyme that reduces intracellular hydrogen peroxide and lipid peroxides. While past research explored regulations of gene expression and biochemical function of this selenoperoxidase, GPX1 has recently been implicated in the onset and development of chronic diseases. Clinical data have shown associations of human GPX1 gene variants with elevated risks of diabetes. Knockout and overexpression of Gpx1 in mice may induce types 1 and 2 diabetes-like phenotypes, respectively. This review assembles the latest advances in this new field of selenium biology, and attempts to postulate signal and molecular mechanisms mediating the role of GPX1 in glucose and lipid metabolism-related diseases. Potential therapies by harnessing the beneficial effects of this ubiquitous redox-modulating enzyme are briefly discussed.

Integration of transcriptome and proteome analyses reveal molecular mechanisms for formation of replant disease in Nelumbo nucifera

The normal growth of Nelumbo nucifera, a widely planted aquatic crop in Asia, was severely ruined by replant disease. The mechanism of replant disease was still unknown in aquatic crops. Complementary transcriptomic and proteomic analyses were performed by comparing seedings of first-year planting (FP) and consecutive planting (CP). 9810 differentially expressed genes (DEGs) were identified between FP and CP. Additionally, 975 differentially expressed proteins (DEPs) were obtained. The correlation of proteome and transcriptome illustrated phenylpropanoid biosynthesis, flavonoid biosynthesis, metabolic pathways, and MAPK signaling pathways were significantly activated. Peroxidase, determined as one of the key proteins in replant disease of N. nucifera, was phylogenetically analyzed. A new depiction of the molecular mechanism causing replant disease in N. nucifera was illustrated. A consecutive monoculture stimulated the generation of reactive oxygen species (ROS) and ethylene, altered the metabolic balance of lignin and flavonoid, and attenuated the activity of antioxidant enzymes through DNA methylation. Therefore, the accumulation of autotoxic allelochemicals and the deficiency of antioxidant enzymes unavoidably suppressed the normal growth and development of replanted N. nucifera.

Complementary transcriptomic and proteomic analyses unveiled the mechanism of replant disease in Nelumbo nucifera, a widely planted aquatic crop in Asia.

Longitudinal effects of developmental bisphenol A, variable diet, and physical activity on age-related methylation in blood

Research indicates that environmental factors can alter DNA methylation, but the specific effects of environmental exposures on epigenetic aging remain unclear. Here, using a mouse model of human-relevant exposures, we tested the hypothesis that early-life exposure to bisphenol A (BPA), variable diet, and/or changes in physical activity would modify rates of age-related methylation at several target regions, as measured from longitudinal blood samples (2, 4, and 10 months old). DNA methylation was quantified at two repetitive elements (LINE-1, IAP), two imprinted genes (Igf2, H19), and one non-imprinted gene (Esr1) in isogenic mice developmentally exposed to Control, Control + BPA (50 µg/kg diet), Western high-fat diet (WHFD), or Western + BPA diets. In blood samples, Esr1 DNA methylation increased significantly with age, but no other investigated loci showed significant age-related methylation. LINE-1 and IAP both showed significant negative environmental deflection by WHFD exposure (P < 0.05). Esr1also showed significant negative environmental deflection by WHFD exposure in female mice (P = 0.02), but not male mice. Physical activity had a non-significant positive effect on age-related Esr1 methylation in female blood, suggesting that it may partially abrogate the effects of WHFD on the aging epigenome. These results suggest that developmental nutritional exposures can modify age-related DNA methylation patterns at a gene related to growth and development. As such, environmental deflection of the aging epigenome may help to explain the growing prevalence of chronic diseases in human populations.

EFFECT OF "TAI CHI" EXERCISE ON ANTIOXIDANT ENZYMES ACTIVITIES AND IMMUNITY FUNCTION IN MIDDLE-AGED PARTICIPANTS

BACKGROUND

"Tai Chi" is a useful exercise that increases physical strength and relax the mind.

MATERIALS AND METHODS

The study investigates effect of "tai chi" exercise on antioxidant enzymes activities and immunity function in participants. These participants were randomly divided into two groups: "tai chi" exercise group (n=25) and control group (n=25). The participants in the "tai chi" group performed "tai chi" exercise for 1 h every day. The participants in the control group didn't perform "tai chi". The exercise lasts for half a year.

RESULTS

"tai chi" exercise increased antioxidant enzymes activities and improve immunity function in participants.

CONCLUSION

"tai chi" exercise is useful for health-keep of participants.

Exercise for the diabetic brain: how physical training may help prevent dementia and Alzheimer's disease in T2DM patients

Epidemiological studies indicate that patients with type 2 diabetes mellitus (T2DM) are at increased risk of developing dementia/Alzheimer's disease (AD). This review, which is based on recent studies, presents a molecular framework that links the two diseases and explains how physical training could help counteract neurodegeneration in T2DM patients. Inflammatory, oxidative, and metabolic changes in T2DM patients cause cerebrovascular complications and can lead to blood-brain-barrier (BBB) breakdown. Peripherally increased pro-inflammatory molecules can then pass the BBB more easily and activate stress-activated pathways, thereby promoting key pathological features of dementia/AD such as brain insulin resistance, mitochondrial dysfunction, and accumulation of neurotoxic beta-amyloid (Aβ) oligomers, leading to synaptic loss, neuronal dysfunction, and cell death. Ceramides can also pass the BBB, induce pro-inflammatory reactions, and disturb brain insulin signaling. In a vicious circle, oxidative stress and the pro-inflammatory environment intensify, leading to further cognitive decline. Low testosterone levels might be a common risk factor in T2DM and AD. Regular physical exercise reinforces antioxidative capacity, reduces oxidative stress, and has anti-inflammatory effects. It improves endothelial function and might increase brain capillarization. Physical training can further counteract dyslipidemia and reduce increased ceramide levels. It might also improve Aβ clearance by up-regulating Aβ transporters and, in some cases, increase basal testosterone levels. In addition, regular physical activity can induce neurogenesis. Physical training should therefore be emphasized as a part of prevention programs developed for diabetic patients to minimize the risk of the onset of neurodegenerative diseases among this specific patient group.

Lower Methylation of the ANGPTL2 Gene in Leukocytes from Post-Acute Coronary Syndrome Patients

DNA methylation is believed to regulate gene expression during adulthood in response to the constant changes in environment. The methylome is therefore proposed to be a biomarker of health through age. ANGPTL2 is a circulating pro-inflammatory protein that increases with age and prematurely in patients with coronary artery diseases; integrating the methylation pattern of the promoter may help differentiate age- vs. disease-related change in its expression. We believe that in a pro-inflammatory environment, ANGPTL2 is differentially methylated, regulating ANGPTL2 expression. To test this hypothesis we investigated the changes in promoter methylation of ANGPTL2 gene in leukocytes from patients suffering from post-acute coronary syndrome (ACS). DNA was extracted from circulating leukocytes of post-ACS patients with cardiovascular risk factors and from healthy young and age-matched controls. Methylation sites (CpGs) found in the ANGPTL2 gene were targeted for specific DNA methylation quantification. The functionality of ANGPTL2 methylation was assessed by an in vitro luciferase assay. In post-ACS patients, C-reactive protein and ANGPTL2 circulating levels increased significantly when compared to healthy controls. Decreased methylation of specific CpGs were found in the promoter of ANGPTL2 and allowed to discriminate age vs. disease associated methylation. In vitro DNA methylation of specific CpG lead to inhibition of ANGPTL2 promoter activity. Reduced leukocyte DNA methylation in the promoter region of ANGPTL2 is associated with the pro-inflammatory environment that characterizes patients with post-ACS differently from age-matched healthy controls. Methylation of different CpGs in ANGPTL2 gene may prove to be a reliable biomarker of coronary disease.