Interactive actions of Bdnf methylation and cell metabolism for building neural resilience under the influence of diet

A shift to a standard diet after exposure to a high-fat, high-sucrose diet from gestation to weaning restores brain metabolism and behavioral flexibility in adult rats

Prolonged consumption of diets high in saturated fat and sugar has been related to obesity and overweight, which in turn are linked to cognitive impairment in both humans and rodents. This has become a current issue, especially in children and adolescents, because these stages are crucial to neurodevelopmental processes and programming of adult behavior. To evaluate the effects of gestational and early exposure to an obesogenic diet, three groups with different dietary patterns were established: high-fat and high-sucrose diet (HFS), standard diet (SD), and a dietary shift from a high-fat, high-sucrose diet to a standard diet after weaning (R). Spatial learning and behavioral flexibility in adult male and female Wistar rats were evaluated using the Morris water maze (MWM) at PND 60. Furthermore, regional brain oxidative metabolism was assessed in the prefrontal cortex and the hippocampus. Contrary to our hypothesis, the HFS diet groups showed similar performance on the spatial learning task as the other groups, although they showed impaired cognitive flexibility. The HFS group had increased brain metabolic capacity compared to that of animals fed the standard diet. Shifting from the HFS diet to the SD diet after weaning restored the brain metabolic capacity in both sexes to levels similar to those observed in animals fed the SD diet. In addition, animals in the R group performed similarly to those fed the SD diet in the Morris water maze in both tasks. However, dietary shift from HFS diet to standard diet after weaning had only moderate sex-dependent effects on body weight and fat distribution. In conclusion, switching from an HFS diet to a balanced diet after weaning would have beneficial effects on behavioral flexibility and brain metabolism, without significant sex differences.

Low-carbohydrate diet as a nutritional intervention in a major depression disorder: focus on relapse prevention

Objectives: Mood disorders are trending to be among the leading causes of years lived with disability. Despite multiple treatment options, around 30% patients with major depressive disorder (MDD) develop treatment resistant depression (TRD) and fail to respond to current pharmacological therapies. This study aimed to explore the potential benefits of nutritional treatment strategies, along with their molecular mechanisms of action, focusing especially on low-carbohydrate diet (LCHD), ketogenic diet (KD) and other strategies based on carbohydrates intake reduction.Methods: A comprehensive literature review was conducted to determine the impact of LCHD on alleviating depressive symptoms in patients with MDD, along with an explanation of its mode of action.Results: The study revealed significant impact of nutritional interventions based on restriction in carbohydrate intake such as LCHD, KD or sugar-sweetened beverages (SSB) exclusion on anxiety or depression symptoms reduction, mood improvement and lower risk of cognitive impairment or depression. The efficacy of these approaches is further substantiated by their underlying molecular mechanisms, mainly brain-derived neurotrophic factor (BDNF) which is a potential key target of sugar restriction diets in terms of neuroplasticity.Discussion: Healthcare professionals may consider implementing LCHD strategies for MDD and TRD patients to modify the disease process, maintain euthymia, and prevent depressive episode relapses. Ranging from the exclusion of SSB to the adherence to rigorous LCHD regimens, these nutritional approaches are safe, straightforward to implement, and may confer benefits for well-being and relapse prevention in this specific patient population.

Physical Exercise Promotes Beneficial Changes on Neurotrophic Factors in Mesolimbic Brain Areas After AMPH Relapse: Involvement of the Endogenous Opioid System

Addiction is a serious public health problem, and the current pharmacotherapy is unable to prevent drug use reinstatement. Studies have focused on physical exercise as a promising coadjuvant treatment. Our research group recently showed beneficial neuroadaptations in the dopaminergic system related to amphetamine-relapse prevention involving physical exercise-induced endogenous opioid system activation (EXE-OS activation). In this context, additional mechanisms were explored to understand the exercise benefits on drug addiction. Male rats previously exposed to amphetamine (AMPH, 4.0 mg/kg) for 8 days were submitted to physical exercise for 5 weeks. EXE-OS activation was blocked by naloxone administration (0.3 mg/kg) 5 min before each physical exercise session. After the exercise protocol, the rats were re-exposed to AMPH for 3 days, and in sequence, euthanasia was performed and the VTA and NAc were dissected. In the VTA, our findings showed increased immunocontent of proBDNF, BDNF, and GDNF and decreased levels of AMPH-induced TrkB; therefore, EXE-OS activation increased all these markers and naloxone administration prevented this exercise-induced effect. In the NAc, the same molecular markers were also increased by AMPH and decreased by EXE-OS activation. In this study, we propose a close relation between EXE-OS activation beneficial influence and a consequent neuroadaptation on neurotrophins and dopaminergic system levels in the mesolimbic brain area, preventing the observed AMPH-relapse behavior. Our outcomes bring additional knowledge concerning addiction neurobiology understanding and show that EXE-OS activation may be a potential adjuvant tool in drug addiction therapy.

Early life nutrition and brain development: breakthroughs, challenges and new horizons

The role of early life nutrition's impact on relevant health outcomes across the lifespan laid the foundation for the field titled the developmental origins of health and disease. Studies in this area initially concentrated on nutrition and the risk of adverse cardio-metabolic and cancer outcomes. More recently the role of nutrition in early brain development and the subsequent influence of later mental health has become more evident. Scientific breakthroughs have elucidated two mechanisms behind long-term nutrient effects on the brain, including the existence of critical periods for certain nutrients during brain development and nutrient-driven epigenetic modifications of chromatin. While multiple nutrients and nutritional conditions have the potential to modify brain development, iron can serve as a paradigm to understand both mechanisms. New horizons in nutritional medicine include leveraging the mechanistic knowledge of nutrient-brain interactions to propose novel nutritional approaches that protect the developing brain through better timing of nutrient delivery and potential reversal of negative epigenetic marks. The main challenge in the field is detecting whether a change in nutritional status truly affects the brain's development and performance in human subjects. To that end, a strong case can be made to develop and utilise bioindicators of a nutrient's effect on the developing brain instead of relying exclusively on biomarkers of the nutrient's status.

Nutrition and Brain Development

All nutrients are essential for brain development, but pre-clinical and clinical studies have revealed sensitive periods of brain development during which key nutrients are critical. An understanding of these nutrient-specific sensitive periods and the accompanying brain regions or processes that are developing can guide effective nutrition interventions as well as the choice of meaningful circuit-specific neurobehavioral tests to best determine outcome. For several nutrients including protein, iron, iodine, and choline, pre-clinical and clinical studies align to identify the same sensitive periods, while for other nutrients, such as long-chain polyunsaturated fatty acids, zinc, and vitamin D, pre-clinical models demonstrate benefit which is not consistently shown in clinical studies. This discordance of pre-clinical and clinical results is potentially due to key differences in the timing, dose, and/or duration of the nutritional intervention as well as the pre-existing nutritional status of the target population. In general, however, the optimal window of success for nutritional intervention to best support brain development is in late fetal and early postnatal life. Lack of essential nutrients during these times can lead to long-lasting dysfunction and significant loss of developmental potential.

Targeting DNA Methylation in the Adult Brain through Diet

Metabolism and nutrition have a significant role in epigenetic modifications such as DNA methylation, which can influence gene expression. Recently, it has been suggested that bioactive nutrients and gut microbiota can alter DNA methylation in the central nervous system (CNS) through the gut-brain axis, playing a crucial role in modulating CNS functions and, finally, behavior. Here, we will focus on the effect of metabolic signals in shaping brain DNA methylation during adulthood. We will provide an overview of potential interactions among diet, gastrointestinal microbiome and epigenetic alterations on brain methylation and behavior. In addition, the impact of different diet challenges on cytosine methylation dynamics in the adult brain will be discussed. Finally, we will explore new ways to modulate DNA hydroxymethylation, which is particularly abundant in neural tissue, through diet.

Early-Life Iron Deficiency Anemia Programs the Hippocampal Epigenomic Landscape

Iron deficiency (ID) anemia is the foremost micronutrient deficiency worldwide, affecting around 40% of pregnant women and young children. ID during the prenatal and early postnatal periods has a pronounced effect on neurodevelopment, resulting in long-term effects such as cognitive impairment and increased risk for neuropsychiatric disorders. Treatment of ID has been complicated as it does not always resolve the long-lasting neurodevelopmental deficits. In animal models, developmental ID results in abnormal hippocampal structure and function associated with dysregulation of genes involved in neurotransmission and synaptic plasticity. Dysregulation of these genes is a likely proximate cause of the life-long deficits that follow developmental ID. However, a direct functional link between iron and gene dysregulation has yet to be elucidated. Iron-dependent epigenetic modifications are one mechanism by which ID could alter gene expression across the lifespan. The jumonji and AT-rich interaction domain-containing (JARID) protein and the Ten-Eleven Translocation (TET) proteins are two families of iron-dependent epigenetic modifiers that play critical roles during neural development by establishing proper gene regulation during critical periods of brain development. Therefore, JARIDs and TETs can contribute to the iron-mediated epigenetic mechanisms by which early-life ID directly causes stable changes in gene regulation across the life span.

Western diet aggravates neuronal insult in post-traumatic brain injury: Proposed pathways for interplay

Traumatic brain injury (TBI) is a global health burden and a major cause of disability and mortality. An early cascade of physical and structural damaging events starts immediately post-TBI. This primary injury event initiates a series of neuropathological molecular and biochemical secondary injury sequelae, that last much longer and involve disruption of cerebral metabolism, mitochondrial dysfunction, oxidative stress, neuroinflammation, and can lead to neuronal damage and death. Coupled to these events, recent studies have shown that lifestyle factors, including diet, constitute additional risk affecting TBI consequences and neuropathophysiological outcomes. There exists molecular cross-talk among the pathways involved in neuronal survival, neuroinflammation, and behavioral outcomes, that are shared among western diet (WD) intake and TBI pathophysiology. As such, poor dietary intake would be expected to exacerbate the secondary damage in TBI. Hence, the aim of this review is to discuss the pathophysiological consequences of WD that can lead to the exacerbation of TBI outcomes. We dissect the role of mitochondrial dysfunction, oxidative stress, neuroinflammation, and neuronal injury in this context. We show that currently available data conclude that intake of a diet saturated in fats, pre- or post-TBI, aggravates TBI, precludes recovery from brain trauma, and reduces the response to treatment.

Mice Lacking the Transcriptional Coactivator PGC-1α Exhibit Hyperactivity

Significant evidence from various sources suggests that structural alterations in mitochondrial function may play a role in both the pathogenesis of mood disorders and the therapeutic effects of available treatments. PGC-1α is a distinct transcriptional regulator designed to mediate the synchronous release of neurotransmitter in the brain and thereby to coordinate a number of gene expression pathways to promote mitochondrial biogenesis and oxidative phosphorylation. The role of PGC-1α in the context of affective disorder phenotypes and treatments has been suggested but not studied in depth. To further investigate the possible involvement of PGC-1α in affective disorders, we generated conditional PGC-1α null mice through transgenic expression of cre recombinase under the control of a Dlx5/6 promoter; cre-mediated excision events were limited to γ-amino-butyric-acid (GABA)-ergic specific neurons. We tested these mice in a battery of behavioral tests related to affective change including spontaneous activity, elevated plus maze, forced swim test, and tail suspension test. Results demonstrated that mice lacking PGC-1α in GABAergic neurons exhibited increased activity across tests that might be related to a mania-like phenotype. These results suggest possible relevance of PGC-1α to affective change, which corresponds with data connecting mitochondrial function and affective disorders and their treatment.

Perioperative Heart-Brain Axis Protection in Obese Surgical Patients: The Nutrigenomic Approach

The number of obese patients undergoing cardiac and noncardiac surgery is rapidly increasing because they are more prone to concomitant diseases, such as diabetes, thrombosis, sleep-disordered breathing, cardiovascular and cerebrovascular disorders. Even if guidelines are already available to manage anesthesia and surgery of obese patients, the assessment of the perioperative morbidity and mortality from heart and brain disorders in morbidly obese surgical patients will be challenging in the next years. The present review will recapitulate the new mechanisms underlying the Heart-brain Axis (HBA) vulnerability during the perioperative period in healthy and morbidly obese patients. Finally, we will describe the nutrigenomics approach, an emerging noninvasive dietary tool, to maintain a healthy body weight and to minimize the HBA propensity to injury in obese individuals undergoing all types of surgery by personalized intake of plant compounds that may regulate the switch from health to disease in an epigenetic manner. Our review provides current insights into the mechanisms underlying HBA response in obese surgical patients and how they are modulated by epigenetically active food constituents.

Maternal Obesity as a Risk Factor for Brain Development and Mental Health in the Offspring

Maternal obesity plays a key role in the health trajectory of the offspring. Although research on this topic has largely focused on the potential of this condition to increase the risk for child obesity, it is becoming more and more evident that it can also significantly impact cognitive function and mental health. The mechanisms underlying these effects are starting to be elucidated and point to the placenta as a critical organ that may mediate changes in the response to stress, immune function and oxidative stress. Long-term effects of maternal obesity may rely upon epigenetic changes in selected genes that are involved in metabolic and trophic regulations of the brain. More recent evidence also indicates the gut microbiota as a potential mediator of these effects. Overall, understanding cause-effect relationships can allow the development of preventive measures that could rely upon dietary changes in the mother and the offspring. Addressing diets appears more feasible than developing new pharmacological targets and has the potential to affect the multiple interconnected physiological pathways engaged by these complex regulations, allowing prevention of both metabolic and mental disorders.

Environmental enrichment, new neurons and the neurobiology of individuality

'Enriched environments' are a key experimental paradigm to decipher how interactions between genes and environment change the structure and function of the brain across the lifespan of an animal. The regulation of adult hippocampal neurogenesis by environmental enrichment is a prime example of this complex interaction. As each animal in an enriched environment will have a slightly different set of experiences that results in downstream differences between individuals, enrichment can be considered not only as an external source of rich stimuli but also to provide the room for individual behaviour that shapes individual patterns of brain plasticity and thus function.

Neuroendocrine drivers of risk and resilience: The influence of metabolism & mitochondria

The manifestation of risk versus resilience has been considered from varying perspectives including genetics, epigenetics, early life experiences, and type and intensity of the challenge with which the organism is faced. Although all of these factors are central to determining risk and resilience, the current review focuses on what may be a final common pathway: metabolism. When an organism is faced with a perturbation to the environment, whether internal or external, appropriate energy allocation is essential to resolving the divergence from equilibrium. This review examines the potential role of metabolism in the manifestation of stress-induced neural compromise. In addition, this review details the current state of knowledge on neuroendocrine factors which are poised to set the tone of the metabolic response to a systemic challenge. The goal is to provide an essential framework for understanding stress in a metabolic context and appreciation for key neuroendocrine signals.

Making sense of gut feelings in the traumatic brain injury pathogenesis

Traumatic brain injury (TBI) is a devastating condition which often initiates a sequel of neurological disorders that can last throughout lifespan. From metabolic perspective, TBI also compromises systemic physiology including the function of body organs with subsequent malfunctions in metabolism. The emerging panorama is that the effects of TBI on the periphery strike back on the brain and exacerbate the overall TBI pathogenesis. An increasing number of clinical reports are alarming to show that metabolic dysfunction is associated with incidence of long-term neurological and psychiatric disorders. The autonomic nervous system, associated hypothalamic-pituitary axis, and the immune system are at the center of the interface between brain and body and are central to the regulation of overall homeostasis and disease. We review the strong association between mechanisms that regulate cell metabolism and inflammation which has important clinical implications for the communication between body and brain. We also discuss the integrative actions of lifestyle interventions such as diet and exercise on promoting brain and body health and cognition after TBI.

Iron as a model nutrient for understanding the nutritional origins of neuropsychiatric disease

Adequate nutrition during the pre- and early-postnatal periods plays a critical role in programming early neurodevelopment. Disruption of neurodevelopment by nutritional deficiencies can result not only in lasting functional deficits, but increased risk of neuropsychiatric disease in adulthood. Historical periods of famine such as the Dutch Hunger Winter and the Chinese Famine have provided foundational evidence for the long-term effects of developmental malnutrition on neuropsychiatric outcomes. Because neurodevelopment is a complex process that consists of many nutrient- and brain-region-specific critical periods, subsequent clinical and pre-clinical studies have aimed to elucidate the specific roles of individual macro- and micronutrient deficiencies in neurodevelopment and neuropsychiatric pathologies. This review will discuss developmental iron deficiency (ID), the most common micronutrient deficiency worldwide, as a paradigm for understanding the role of early-life nutrition in neurodevelopment and risk of neuropsychiatric disease. We will review the epidemiologic data linking ID to neuropsychiatric dysfunction, as well as the underlying structural, cellular, and molecular mechanisms that are thought to underlie these lasting effects. Understanding the mechanisms driving lasting dysfunction and disease risk is critical for development and implementation of nutritional policies aimed at preventing nutritional deficiencies and their long-term sequelae.

System biology approach intersecting diet and cell metabolism with pathogenesis of brain disorders

The surge in meals high in calories has prompted an epidemic of metabolic disorders around the world such that the elevated incidence of obese and diabetic individuals is alarming. New research indicates that metabolic disorders pose a risk for neurological and psychiatric conditions including stroke, Alzheimer's disease, Huntington's disease, and depression, all of which have a metabolic component. These relationships are rooted to a dysfunctional interaction between molecular processes that regulate energy metabolism and synaptic plasticity. The strong adaptive force of dietary factors on shaping the brain during evolution can be manipulated to transform the interaction between cell bioenergetics and epigenome with the aptitude to promote long-lasting brain healthiness. A thorough understanding of the association between the broad action of nutrients and brain fitness requires high level data processing empowered with the capacity to integrate information from a multitude of molecular entities and pathways. Nutritional systems biology is emerging as a viable approach to elucidate the multiple molecular layers involved in information processing in cells, tissues, and organ systems in response to diet. Information about the wide range of cellular and molecular interactions elicited by foods on the brain and cognitive plasticity is crucial for the design of public health initiatives for curtailing the epidemic of metabolic and brain disorders.

Nutritional influences on brain development

There is increasing evidence from preclinical and human studies that nutrition in the late foetal and early neonatal period has a significant impact on neurodevelopment across the lifespan. Certain nutrients have particularly large effects in this time period, and their deficits cause greater long-term risk. The mechanisms by which nutrients influence early brain growth and the sensitive periods for when certain nutrients should be provided are being elucidated. Assessments of nutritional status that index brain growth and predict long-term development are important to assess the efficacy of early life nutritional therapies.

CONCLUSION

Optimizing nutrition during foetal and early postnatal life is a golden opportunity to impact neurodevelopment and brain function across the lifespan.

Atypical fetal development: Fetal alcohol syndrome, nutritional deprivation, teratogens, and risk for neurodevelopmental disorders and psychopathology

Accumulating evidence indicates that the fetal environment plays an important role in brain development and sets the brain on a trajectory across the life span. An abnormal fetal environment results when factors that should be present during a critical period of development are absent or when factors that should not be in the developing brain are present. While these factors may acutely disrupt brain function, the real cost to society resides in the long-term effects, which include important mental health issues. We review the effects of three factors, fetal alcohol exposure, teratogen exposure, and nutrient deficiencies, on the developing brain and the consequent risk for developmental psychopathology. Each is reviewed with respect to the evidence found in epidemiological and clinical studies in humans as well as preclinical molecular and cellular studies that explicate mechanisms of action.

Toxicity, recovery, and resilience in a 3D dopaminergic neuronal in vitro model exposed to rotenone

To date, most in vitro toxicity testing has focused on acute effects of compounds at high concentrations. This testing strategy does not reflect real-life exposures, which might contribute to long-term disease outcome. We used a 3D-human dopaminergic in vitro LUHMES cell line model to determine whether effects of short-term rotenone exposure (100 nM, 24 h) are permanent or reversible. A decrease in complex I activity, ATP, mitochondrial diameter, and neurite outgrowth were observed acutely. After compound removal, complex I activity was still inhibited; however, ATP levels were increased, cells were electrically active and aggregates restored neurite outgrowth integrity and mitochondrial morphology. We identified significant transcriptomic changes after 24 h which were not present 7 days after wash-out. Our results suggest that testing short-term exposures in vitro may capture many acute effects which cells can overcome, missing adaptive processes, and long-term mechanisms. In addition, to study cellular resilience, cells were re-exposed to rotenone after wash-out and recovery period. Pre-exposed cells maintained higher metabolic activity than controls and presented a different expression pattern in genes previously shown to be altered by rotenone. NEF2L2, ATF4, and EAAC1 were downregulated upon single hit on day 14, but unchanged in pre-exposed aggregates. DAT and CASP3 were only altered after re-exposure to rotenone, while TYMS and MLF1IP were downregulated in both single-exposed and pre-exposed aggregates. In summary, our study shows that a human cell-based 3D model can be used to assess cellular adaptation, resilience, and long-term mechanisms relevant to neurodegenerative research.

Effects of Low Phytanic Acid-Concentrated DHA on Activated Microglial Cells: Comparison with a Standard Phytanic Acid-Concentrated DHA

Docosahexaenoic acid (DHA, 22:6 n-3) is an essential omega-3 (ω-3) long chain polyunsaturated fatty acid of neuronal membranes involved in normal growth, development, and function. DHA has been proposed to reduce deleterious effects in neurodegenerative processes. Even though, some inconsistencies in findings from clinical and pre-clinical studies with DHA could be attributed to the presence of phytanic acid (PhA) in standard DHA treatments. Thus, the aim of our study was to analyze and compare the effects of a low PhA-concentrated DHA with a standard PhA-concentrated DHA under different neurotoxic conditions in BV-2 activated microglial cells. To this end, mouse microglial BV-2 cells were stimulated with either lipopolysaccharide (LPS) or hydrogen peroxide (H₂O₂) and co-incubated with DHA 50 ppm of PhA (DHA (PhA:50)) or DHA 500 ppm of PhA (DHA (PhA:500)). Cell viability, superoxide anion (O₂^-) production, Interleukin 6 (L-6), cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), glutathione peroxidase (GtPx), glutathione reductase (GtRd), Caspase-3, and the brain-derived neurotrophic factor (BDNF) protein expression were explored. Low PhA-concentrated DHA protected against LPS or H₂O₂-induced cell viability reduction in BV-2 activated cells and O₂^- production reduction compared to DHA (PhA:500). Low PhA-concentrated DHA also decreased COX-2, IL-6, iNOS, GtPx, GtRd, and SOD-1 protein expression when compared to DHA (PhA:500). Furthermore, low PhA-concentrated DHA increased BDNF protein expression in comparison to DHA (PhA:500). The study provides data supporting the beneficial effect of low PhA-concentrated DHA in neurotoxic injury when compared to a standard PhA-concentrated DHA in activated microglia.

Iron assessment to protect the developing brain

Iron deficiency (ID) before the age of 3 y can lead to long-term neurological deficits despite prompt diagnosis of ID anemia (IDA) by screening of hemoglobin concentrations followed by iron treatment. Furthermore, pre- or nonanemic ID alters neurobehavioral function and is 3 times more common than IDA in toddlers. Given the global prevalence of ID and the enormous societal cost of developmental disabilities across the life span, better methods are needed to detect the risk of inadequate concentrations of iron for brain development (i.e., brain tissue ID) before dysfunction occurs and to monitor its amelioration after diagnosis and treatment. The current screening and treatment strategy for IDA fails to achieve this goal for 3 reasons. First, anemia is the final state in iron depletion. Thus, the developing brain is already iron deficient when IDA is diagnosed owing to the prioritization of available iron to red blood cells over all other tissues during negative iron balance in development. Second, brain ID, independently of IDA, is responsible for long-term neurological deficits. Thus, starting iron treatment after the onset of IDA is less effective than prevention. Multiple studies in humans and animal models show that post hoc treatment strategies do not reliably prevent ID-induced neurological deficits. Third, most currently used indexes of ID are population statistical cutoffs for either hematologic or iron status but are not bioindicators of brain ID and brain dysfunction in children. Furthermore, their relation to brain iron status is not known. To protect the developing brain, there is a need to generate serum measures that index brain dysfunction in the preanemic stage of ID, assess the ability of standard iron indicators to detect ID-induced brain dysfunction, and evaluate the efficacy of early iron treatment in preventing ID-induced brain dysfunction.

Assessment of Brain Derived Neurotrophic Factor in hair to study stress responses: A pilot investigation

To study pathogenic stress-effects in health and disease, it is paramount to define easy access parameters for non-invasive analysis of biological change in response to stress. Hair samples successfully provide this access for the study of hypothalamus-pituitary-adrenal axis (HPA) changes. In this study, we assess the hair expression and corresponding epigenetic changes of a neurotrophin essential for autonomic nervous system function and mental health: brain derived neurotrophic factor (BDNF). In three independent studies in healthy academic volunteers (study I: German students, N=36; study II, German academic population sample, N=28; study III: Mexican students, N=115), BDNF protein expression or BDNF gene (BDNF) histone acetylation was determined. Simultaneously, mental distress and distress-associated somatic complaints were assessed by self-report. In study I, we found a negative correlation between hair-BDNF protein level and hair-cortisol as well as between hair-BDNF and somatic complaints, while hair-cortisol correlated positively with mental distress. In study II, we found a negative correlation between H4 histone acetylation at the BDNF gene P4-promoter and somatic complaints. Regression analysis confirmed confounder stability of associations in both studies. In study III, we confirmed study I and found lower hair-BDNF protein level in volunteers with high somatic complaints, who also reported higher mental distress during the end of term exams. The results indicate that BDNF protein levels can be detected in clipped hair and are associated with somatic complaints and stress in life. In addition, we concluded that plucked hair can provide material for the study of epigenetic changes in stress-affected tissues. These tools can prove valuable for future studies on distress, both under experimental and field conditions.

Dietary docosahexaenoic acid (DHA) as lysophosphatidylcholine, but not as free acid, enriches brain DHA and improves memory in adult mice

Docosahexaenoic acid (DHA) is uniquely concentrated in the brain, and is essential for its function, but must be mostly acquired from diet. Most of the current supplements of DHA, including fish oil and krill oil, do not significantly increase brain DHA, because they are hydrolyzed to free DHA and are absorbed as triacylglycerol, whereas the transporter at blood brain barrier is specific for phospholipid form of DHA. Here we show that oral administration of DHA to normal adult mice as lysophosphatidylcholine (LPC) (40 mg DHA/kg) for 30 days increased DHA content of the brain by >2-fold. In contrast, the same amount of free DHA did not increase brain DHA, but increased the DHA in adipose tissue and heart. Moreover, LPC-DHA treatment markedly improved the spatial learning and memory, as measured by Morris water maze test, whereas free DHA had no effect. The brain derived neurotrophic factor increased in all brain regions with LPC-DHA, but not with free DHA. These studies show that dietary LPC-DHA efficiently increases brain DHA content and improves brain function in adult mammals, thus providing a novel nutraceutical approach for the prevention and treatment of neurological diseases associated with DHA deficiency, such as Alzheimer’s disease.

MeCP2 and CTCF: enhancing the cross-talk of silencers

This paper provides a brief introductory review of the most recent advances in our knowledge about the structural and functional aspects of two transcriptional regulators: MeCP2, a protein whose mutated forms are involved in Rett syndrome; and CTCF, a constitutive transcriptional insulator. This is followed by a description of the PTMs affecting these two proteins and an analysis of their known interacting partners. A special emphasis is placed on the recent studies connecting these two proteins, focusing on the still poorly understood potential structural and functional interactions between the two of them on the chromatin substrate. An overview is provided for some of the currently known genes that are dually regulated by these two proteins. Finally, a model is put forward to account for their possible involvement in their regulation of gene expression.

Lifestyle Modulators of Neuroplasticity: How Physical Activity, Mental Engagement, and Diet Promote Cognitive Health during Aging

The number of the elderly across the globe will approximate 2.1 billion by 2050. Juxtaposed against this burgeoning segment of the population is evidence that nonpathological aging is associated with an increased risk for cognitive decline in a variety of domains, changes that can cause mild disability even before the onset of dementia. Given that pharmacological treatments that mitigate dementia are still outstanding, alternative therapeutic options are being investigated increasingly. The results from translational studies have shown that modifiable lifestyle factors-including physical activity, cognitive engagement, and diet-are a key strategy for maintaining brain health during aging. Indeed, a multiplicity of studies has demonstrated relationships between lifestyle factors, brain structure and function, and cognitive function in aging adults. For example, physical activity and diet modulate common neuroplasticity substrates (neurotrophic signaling, neurogenesis, inflammation, stress response, and antioxidant defense) in the brain whereas cognitive engagement enhances brain and cognitive reserve. The aims of this review are to evaluate the relationship between modifiable lifestyle factors, neuroplasticity, and optimal brain health during aging; to identify putative mechanisms that contribute positive brain aging; and to highlight future directions for scientists and clinicians. Undoubtedly, the translation of cutting-edge knowledge derived from the field of cognitive neuroscience will advance our understanding and enhance clinical treatment interventions as we endeavor to promote brain health during aging.

Anxiety and Epigenetics

Anxiety disorders are highly prevalent psychiatric disorders often comorbid with depression and substance abuse. Twin studies have shown that anxiety disorders are moderately heritable. Yet, genome-wide association studies (GWASs) have failed to identify gene(s) significantly associated with diagnosis suggesting a strong role for environmental factors and the epigenome. A number of anxiety disorder subtypes are considered "stress related." A large focus of research has been on the epigenetic and anxiety-like behavioral consequences of stress. Animal models of anxiety-related disorders have provided strong evidence for the role of stress on the epigenetic control of the hypothalamic-pituitary-adrenal (HPA) axis and of stress-responsive brain regions. Neuroepigenetics may continue to explain individual variation in susceptibility to environmental perturbations and consequently anxious behavior. Behavioral and pharmacological interventions aimed at targeting epigenetic marks associated with anxiety may prove fruitful in developing treatments.

Neuroplasticity and Clinical Practice: Building Brain Power for Health

The focus of this review is on driving neuroplasticity in a positive direction using evidence-based interventions that also have the potential to improve general health. One goal is to provide an overview of the many ways new neuroscience can inform treatment protocols to empower and motivate clients to make the lifestyle choices that could help build brain power and could increase adherence to healthy lifestyle changes that have also been associated with simultaneously enhancing vigorous longevity, health, happiness, and wellness. Another goal is to explore the use of a focus in clinical practice on helping clients appreciate this new evidence and use evolving neuroscience in establishing individualized goals, designing strategies for achieving them and increasing treatment compliance. The timing is urgent for such interventions with goals of enhancing brain health across the lifespan and improving statistics on dementia worldwide.

Inhibition of DNA Methylation in the Developing Rat Brain Disrupts Sexually Dimorphic Neurobehavioral Phenotypes in Adulthood

Accumulating evidence indicates a critical implication of DNA methylation in the brain development. We aim to determine whether the disruption of DNA methylation patterns in the developing brain adversely affects neurobehavioral phenotypes later in life in a sex-dependent manner. 5-Aza-2'-deoxycytidine (5-Aza), a DNA methylation inhibitor, was administered in newborn rats from postnatal day 1 to 3. Neurobehavioral outcomes were analyzed at 3 months of age. 5-Aza treatment significantly inhibited DNA methyltransferase activity and decreased global DNA methylation levels in neonatal rat brains, resulting in asymmetric growth restriction with the increased brain to body weight ratio in both male and female rats at 14 days and 3 months of age. Compared with the saline control, 5-Aza treatment significantly improved performance of male rats on the rotarod test, and 5-Aza-treated female rats demonstrated less anxiety, less depression-like behaviors, and enhanced spatial learning performance. Of importance, neonatal 5-Aza treatment eliminated the sexually dimorphic differences in several neurobehavioral tests in adult rats. In addition, 5-Aza treatment decreased promoter methylation of brain-derived neurotrophic factor (BDNF) gene and significantly increased BDNF mRNA and protein abundance in the prefrontal cortex and hippocampus of female rats in a sex-dependent manner. Thus, brain DNA methylation appears to be essential for sexual differentiations of the brain and neurobehavioral functions. Inhibition of DNA methylation in the developing brain of early life induces aberrant neurobehavioral profiles and disrupts sexually dimorphic neurobehavioral phenotypes in adulthood, of which altered BDNF signaling pathway may be an important mediator.

Environmentally induced epigenetic toxicity: potential public health concerns

Throughout our lives, epigenetic processes shape our development and enable us to adapt to a constantly changing environment. Identifying and understanding environmentally induced epigenetic change(s) that may lead to adverse outcomes is vital for protecting public health. This review, therefore, examines the present understanding of epigenetic mechanisms involved in the mammalian life cycle, evaluates the current evidence for environmentally induced epigenetic toxicity in human cohorts and rodent models and highlights the research considerations and implications of this emerging knowledge for public health and regulatory toxicology. Many hundreds of studies have investigated such toxicity, yet relatively few have demonstrated a mechanistic association among specific environmental exposures, epigenetic changes and adverse health outcomes in human epidemiological cohorts and/or rodent models. While this small body of evidence is largely composed of exploratory in vivo high-dose range studies, it does set a precedent for the existence of environmentally induced epigenetic toxicity. Consequently, there is worldwide recognition of this phenomenon, and discussion on how to both guide further scientific research towards a greater mechanistic understanding of environmentally induced epigenetic toxicity in humans, and translate relevant research outcomes into appropriate regulatory policies for effective public health protection.

Early life exposure to obesogenic diets and learning and memory dysfunction

Obesogenic dietary factors, such as simple sugars and saturated fatty acids, have been linked to memory impairments and hippocampal dysfunction. Recent evidence suggests that the brain may be particularly vulnerable to the effects of obesogenic diets during early life periods of rapid growth, maturation, and brain development. Investigations utilizing rodent models indicate that early life exposure to "high fat diets" (40-65% kcal derived from fat) or simple sugars (sucrose or high fructose corn syrup) can impair hippocampus-dependent learning and memory processes. In some cases, these deficits occur independent of obesity and metabolic derangement and can persist into adulthood despite dietary intervention. Various neurobiological mechanisms have been identified that may link early life consumption of obesogenic dietary factors with hippocampal dysfunction, including increased neuroinflammation and reduced neurotrophin mediated regulation of neurogenesis and synaptic plasticity. Age, duration of exposure, and dietary composition are key variables contributing to the interaction between early life diet and cognitive dysfunction, however, more research is needed to unravel the precise critical windows of development and causal dietary factors.

Don't worry; be informed about the epigenetics of anxiety

Epigenetic processes regulate gene expression independent of the DNA sequence and are increasingly being investigated as contributors to the development of behavioral disorders. Environmental insults, such as stress, diet, or toxin exposure, can affect epigenetic mechanisms, including chromatin remodeling, DNA methylation, and non-coding RNAs that, in turn, alter the organism's phenotype. In this review, we examine the literature, derived at both the preclinical (animal) and clinical (human) levels, on epigenetic alterations associated with anxiety disorders. Using animal models of anxiety, researchers have identified epigenetic changes in several limbic and cortical brain regions known to be involved in stress and emotion responses. Environmental manipulations have been imposed prior to conception, during prenatal or early postnatal periods, and at juvenile and adult ages. Time of perturbation differentially affects the epigenome and many changes are brain region-specific. Although some sex-dependent effects are reported in animal studies, more research employing both sexes is needed particularly given that females exhibit a disproportionate number of anxiety disorders. The human literature is in its infancy but does reveal some epigenetic associations with anxiety behaviors and disorders. In particular, effects in monoaminergic systems are seen in line with evidence from etiological and treatment research. Further, there is evidence that epigenetic changes may be inherited to affect subsequent generations. We speculate on how epigenetic processes may interact with genetic contributions to inform prevention and treatment strategies for those who are at risk for or have anxiety disorders.

Systems Nutrigenomics Reveals Brain Gene Networks Linking Metabolic and Brain Disorders

Nutrition plays a significant role in the increasing prevalence of metabolic and brain disorders. Here we employ systems nutrigenomics to scrutinize the genomic bases of nutrient–host interaction underlying disease predisposition or therapeutic potential. We conducted transcriptome and epigenome sequencing of hypothalamus (metabolic control) and hippocampus (cognitive processing) from a rodent model of fructose consumption, and identified significant reprogramming of DNA methylation, transcript abundance, alternative splicing, and gene networks governing cell metabolism, cell communication, inflammation, and neuronal signaling. These signals converged with genetic causal risks of metabolic, neurological, and psychiatric disorders revealed in humans. Gene network modeling uncovered the extracellular matrix genes Bgn and Fmod as main orchestrators of the effects of fructose, as validated using two knockout mouse models. We further demonstrate that an omega-3 fatty acid, DHA, reverses the genomic and network perturbations elicited by fructose, providing molecular support for nutritional interventions to counteract diet-induced metabolic and brain disorders. Our integrative approach complementing rodent and human studies supports the applicability of nutrigenomics principles to predict disease susceptibility and to guide personalized medicine.

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Fructose promotes transcriptomic and epigenomic reprogramming to perturb brain networks linking metabolism and brain function.

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The extracellular matrix genes Bgn and Fmod emerge as key regulators of gene networks responsive to fructose.

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The omega-3 fatty acid DHA reverses fructose-induced genomic and network reprogramming.

Meng et al. report fructose as a powerful inducer of genomic and epigenomic variability with the capacity to reorganize gene networks critical for central metabolic regulation and neuronal processes in the brain; conversely, an omega-3 fatty acid, DHA, has the potential to normalize the genomic impact of fructose. Our findings help explain the pathogenic actions of fructose on prevalent metabolic and brain disorders and provide proof-of-concept for nutritional remedies supported by nutrigenomics evidence. Our integrative approach complementing rodent and human studies supports the applicability of nutrigenomics principles to predict disease susceptibility and to guide personalized medicine.

Genetics of anxiety disorders: Genetic epidemiological and molecular studies in humans

This review provides a broad overview of the state of research in the genetics of anxiety disorders (AD). Genetic epidemiological studies report a moderate level of familial aggregation (odds ratio: 4-6) and heritability estimates are about 30-50%. Twin studies suggest that the genetic architecture of AD is not isomorphic with their classifications, sharing risk factors with each other. So far, linkage and association studies of AD have produced inconclusive results. Genome-wide association studies of AD can provide an unbiased survey of common genetic variations across the entire genome. Given the shared causes of AD that transcend our current diagnostic classifications, clustering anxiety phenotypes into broader groups may be a powerful approach to identifying susceptibility locus for AD. Using such a shared genetic risk factor, meta-analyses of genome-wide association studies of AD conducted by large consortia are needed. Environmental factors also make a substantial contribution to the cause of AD. Although candidate gene studies of gene by environmental (G × E) interaction have appeared recently, no genome-wide search for G × E interactions have been performed. Epigenetic modification of DNA appears to have important effects on gene expression mediating environmental influences on disease risk. Given that G × E can be linked to an epigenetic modification, a combination analysis of genome-wide G × E interaction and methylation could be an alternative method to find risk variants for AD. This genetic research will enable us to utilize more effective strategies for the prevention and treatment of AD in the near future.