Melatonin prevents neonatal dexamethasone induced programmed hypertension: histone deacetylase inhibition

Interplay between maternal nutrition and epigenetic programming on offspring hypertension

Recent human and animal studies have delineated hypertension can develop in the earliest stage of life. A lack or excess of particular nutrients in the maternal diet may impact the expression of genes associated with BP, leading to an increased risk of hypertension in adulthood. Modulations in gene expression could be caused by epigenetic mechanisms through aberrant DNA methylation, histone modification, and microRNAs (miRNAs). Several molecular mechanisms for the developmental programming of hypertension, including oxidative stress, dysregulated nutrient-sensing signal, aberrant renin-angiotensin system, and dysbiotic gut microbiota have been associated with epigenetic programming. Conversely, maternal nutritional interventions such as amino acids, melatonin, polyphenols, resveratrol or short chain fatty acids may work as epigenetic modifiers to trigger protective epigenetic modifications and prevent offspring hypertension. We present a current perspective of maternal malnutrition that can cause fetal programming and the potential of epigenetic mechanisms lead to offspring hypertension. We also discuss the opportunities of dietary nutrients or nutraceuticals as epigenetic modifiers to counteract those adverse programming actions for hypertension prevention. The extent to which aberrant epigenetic changes can be reprogrammed or reversed by maternal dietary interventions in order to prevent human hypertension remains to be established. Continued research is necessary to evaluate the interaction between maternal malnutrition and epigenetic programming, as well as a greater focus on nutritional interventions for hypertension prevention towards their use in clinical translation.

Melatonin Use during Pregnancy and Lactation Complicated by Oxidative Stress: Focus on Offspring's Cardiovascular-Kidney-Metabolic Health in Animal Models

Cardiovascular-kidney-metabolic (CKM) syndrome has emerged as a major global public health concern, posing a substantial threat to human health. Early-life exposure to oxidative stress may heighten vulnerability to the developmental programming of adult diseases, encompassing various aspects of CKM syndrome. Conversely, the initiation of adverse programming processes can potentially be thwarted through early-life antioxidant interventions. Melatonin, originally recognized for its antioxidant properties, is an endogenous hormone with diverse biological functions. While melatonin has demonstrated benefits in addressing disorders linked to oxidative stress, there has been comparatively less focus on investigating its reprogramming effects on CKM syndrome. This review consolidates the current knowledge on the role of oxidative stress during pregnancy and lactation in inducing CKM traits in offspring, emphasizing the underlying mechanisms. The multifaceted role of melatonin in regulating oxidative stress, mediating fetal programming, and preventing adverse outcomes in offspring positions it as a promising reprogramming strategy. Currently, there is a lack of sufficient information in humans, and the available evidence primarily originates from animal studies. This opens up new avenues for novel preventive intervention in CKM syndrome.

Melatonin and Kidney Health: From Fetal Stage to Later Life

Melatonin, an endogenous hormone mainly released at night by the pineal gland, has multifaceted biofunctions. Emerging evidence points to melatonin having a crucial role in kidney health and disease. As the prevalence of chronic kidney disease (CKD) is still rising, a superior strategy to advance global kidney health is needed to not just treat CKD, but prevent it early on. Adult kidney disease can have its origins in early life. This review aims to evaluate the recent literature regarding melatonin's effect on kidney development, its clinical uses in the early stage of life, animal models documenting preventive applications of melatonin on offspring's kidney-related disease, and a thorough summary of therapeutic considerations concerning melatonin supplementation.

The molecular mechanisms in prenatal drug exposure-induced fetal programmed adult cardiovascular disease

The "developmental origins of health and disease" (DOHaD) hypothesis posits that early-life environmental exposures have a lasting impact on individual's health and permanently shape growth, structure, and metabolism. This reprogramming, which results from fetal stress, is believed to contribute to the development of adulthood cardiovascular diseases such as hypertension, coronary artery disease, heart failure, and increased susceptibility to ischemic injuries. Recent studies have shown that prenatal exposure to drugs, such as glucocorticoids, antibiotics, antidepressants, antiepileptics, and other toxins, increases the risk of adult-onset cardiovascular diseases. In addition, observational and animal experimental studies have demonstrated the association between prenatal drug exposure and the programming of cardiovascular disease in the offspring. The molecular mechanisms underlying these effects are still being explored but are thought to involve metabolism dysregulation. This review summarizes the current evidence on the relationship between prenatal drug exposure and the risk of adult cardiovascular disorders. Additionally, we present the latest insights into the molecular mechanisms that lead to programmed cardiovascular phenotypes after prenatal drug exposure.

Maternal melatonin treatment rescues endocrine, inflammatory, and transcriptional deregulation in the adult rat female offspring from gestational chronodisruption

Introduction

Gestational chronodisruption impact maternal circadian rhythms, inhibiting the nocturnal increase of melatonin, a critical hormone that contributes to maternal changes adaptation, entrains circadian rhythms, and prepares the fetus for birth and successful health in adulthood. In rats, we know that gestational chronodisruption by maternal chronic photoperiod shifting (CPS) impaired maternal melatonin levels and resulted in long-term metabolic and cardiovascular effects in adult male offspring. Here, we investigated the consequences of CPS on mother and adult female offspring and explored the effects of melatonin maternal supplementation. Also, we tested whether maternal melatonin administration during gestational chronodisruption rescues maternal circadian rhythms, pregnancy outcomes, and transcriptional functions in adult female offspring.

Methods

Female rats raised and maintained in photoperiod 12:12 light: dark were mated and separated into three groups: (a) Control photoperiod 12:12 (LD); (b) CPS photoperiod; and (c) CPS+Mel mothers supplemented with melatonin in the drinking water throughout gestation. In the mother, we evaluated maternal circadian rhythms by telemetry and pregnancy outcomes, in the long-term, we study adult female offspring by evaluating endocrine and inflammatory markers and the mRNA expression of functional genes involved in adrenal, cardiac, and renal function.

Results

In the mothers, CPS disrupted circadian rhythms of locomotor activity, body temperature, and heart rate and increased gestational length by almost 12-h and birth weight by 12%, all of which were rescued by maternal melatonin administration. In the female offspring, we found blunted day/night differences in circulating levels of melatonin and corticosterone, abnormal patterns of pro-inflammatory cytokines Interleukin-1a (IL1a), Interleukin-6 (IL6), and Interleukin-10 (IL10); and differential expression in 18 out of 24 adrenal, cardiac, and renal mRNAs evaluated.

Conclusion

Maternal melatonin contributed to maintaining the maternal circadian rhythms in mothers exposed to CPS, and the re-establishing the expression of 60% of the altered mRNAs to control levels in the female offspring. Although we did not analyze the effects on kidney, adrenal, and heart physiology, our results reinforce the idea that altered maternal circadian rhythms, resulting from exposure to light at night, should be a mechanism involved in the programming of Non-Communicable Diseases.

Increasing angiotensin-converting enzyme 1 regulated by histone 3 lysine 27 hyperacetylation in high-fat diet-induced hypertensive rat kidney

BACKGROUND

Obesity is a key risk factor of hypertension. Angiotensin-converting enzyme 1 (ACE1) is a key enzyme involved in the renin-angiotensin-aldosterone system (RAAS), which contributes to obesity-related hypertension (OrHTN). Emerging evidence has shown that histone acetylation is also involved in OrHTN. As kidney is an effector organ that activates the RAAS by secreting renin after hypertension occurs, this study aimed to explore the regulatory role of histone acetylation on renal RAAS expression.

METHODS

Nineteen male Wistar rats were randomly divided into a control group ( n  = 9, fed normal chow) and a high-fat diet (HFD) group ( n  = 10, fed HFD for 16 weeks). The renal transcriptome and histone acetylation spectrum was analyzed by RNA sequencing and tandem mass spectrometry and was further confirmed by RT-qPCR, western blot, and immunohistochemistry. Then, chromatin immunoprecipitation (ChIP)-qPCR analysis was performed for the detection of DNA-protein interaction.

RESULTS

After 16-week HFD, the rats became obese with increased plasma triglyceride and high blood pressure. Increased ACE1 and histone 3 lysine 27 acetylation (H3K27ac) expression levels were found in OrHTN rat kidneys. The following ChIP-qPCR analysis illustrated that the upregulation of ACE1 transcription was mediated by increased H3K27ac.

CONCLUSION

H3K27ac could be an important histone acetylation site that activates renal ACE1 in HFD-induced hypertensive rats.

Hypotensive effects of melatonin in rats: Focus on the model, measurement, application, and main mechanisms

The hypotensive effects of melatonin are based on a negative correlation between melatonin levels and blood pressure in humans. However, there is a positive correlation in nocturnal animals that are often used as experimental models in cardiovascular research, and the hypotensive effects and mechanism of melatonin action are often investigated in rats and mice. In rats, the hypotensive effects of melatonin have been studied in normotensive and spontaneously or experimentally induced hypertensive strains. In experimental animals, blood pressure is often measured indirectly during the light (passive) phase of the day by tail-cuff plethysmography, which has limitations regarding data quality and animal well-being compared to telemetry. Melatonin is administered to rats in drinking water, subcutaneously, intraperitoneally, or microinjected into specific brain areas at different times. Experimental data show that the hypotensive effects of melatonin depend on the experimental animal model, blood pressure measurement technique, and the route, time and duration of melatonin administration. The hypotensive effects of melatonin may be mediated through specific membrane G-coupled receptors located in the heart and arteries. Due to melatonin's lipophilic nature, its potential hypotensive effects can interfere with various regulatory mechanisms, such as nitric oxide and reactive oxygen species production and activation of the autonomic nervous and circadian systems. Based on the research conducted on rats, the cardiovascular effects of melatonin are modulatory, delayed, and indirect.

Hypertension and renal disease programming: focus on the early postnatal period

The developmental origin of hypertension and renal disease is a concept highly supported by strong evidence coming from both human and animal studies. During development there are periods in which the organs are more vulnerable to stressors. Such periods of susceptibility are also called 'sensitive windows of exposure'. It was shown that as earlier an adverse event occurs; the greater are the consequences for health impairment. However, evidence show that the postnatal period is also quite important for hypertension and renal disease programming, especially in rodents because they complete nephrogenesis postnatally, and it is also important during preterm human birth. Considering that the developing kidney is vulnerable to early-life stressors, renal programming is a key element in the developmental programming of hypertension and renal disease. The purpose of this review is to highlight the great number of studies, most of them performed in animal models, showing the broad range of stressors involved in hypertension and renal disease programming, with a particular focus on the stressors that occur during the early postnatal period. These stressors mainly include undernutrition or specific nutritional deficits, chronic behavioral stress, exposure to environmental chemicals, and pharmacological treatments that affect some important factors involved in renal physiology. We also discuss the common molecular mechanisms that are activated by the mentioned stressors and that promote the appearance of these adult diseases, with a brief description on some reprogramming strategies, which is a relatively new and promising field to treat or to prevent these diseases.

Prenatal dexamethasone exposure induced pancreatic β-cell dysfunction and glucose intolerance of male offspring rats: Role of the epigenetic repression of ACE2

The prevalence of diabetes in children and adolescents has been rising gradually, which is relevant to adverse environment during development, especially prepartum. We aimed to explore the effects of prenatal dexamethasone exposure (PDE) on β-cell function and glucose homeostasis in juvenile offspring rats. Pregnant Wistar rats were subcutaneously administered with dexamethasone [0.1, 0.2, 0.4mg/(kg.d)] from gestational day 9 to 20. PDE impaired glucose tolerance in the male offspring rather than the females. In male offspring, PDE impaired the development and function of β-cells, accompanied with lower H3K9ac, H3K14ac and H3K27ac levels in the promoter region of angiotensin-converting enzyme 2 (ACE2) as well as suppressed ACE2 expression. Meanwhile, PDE increased expression of glucocorticoid receptor (GR) and histone deacetylase 3 (HDAC3) in fetal pancreas. Dexamethasone also inhibited ACE2 expression and insulin production in vitro. Recombinant expression of ACE2 restored insulin production inhibited by dexamethasone. In addition, dexamethasone activated GR and HDAC3, increased protein interaction of GR with HDAC3, and promoted the binding of GR-HDAC3 complex to ACE2 promoter region. Both RU486 and TSA abolished dexamethasone-induced decline of histone acetylation and ACE2 expression. In summary, suppression of ACE2 is involved in PDE induced β-cell dysfunction and glucose intolerance in juvenile male offspring rats.

The Prospective Application of Melatonin in Treating Epigenetic Dysfunctional Diseases

In the past, different human disorders were described by scientists from the perspective of either environmental factors or just by genetically related mechanisms. The rise in epigenetic studies and its modifications, i.e., heritable alterations in gene expression without changes in DNA sequences, have now been confirmed in diseases. Modifications namely, DNA methylation, posttranslational histone modifications, and non-coding RNAs have led to a better understanding of the coaction between epigenetic alterations and human pathologies. Melatonin is a widely-produced indoleamine regulator molecule that influences numerous biological functions within many cell types. Concerning its broad spectrum of actions, melatonin should be investigated much more for its contribution to the upstream and downstream mechanistic regulation of epigenetic modifications in diseases. It is, therefore, necessary to fill the existing gaps concerning corresponding processes associated with melatonin with the physiological abnormalities brought by epigenetic modifications. This review outlines the findings on melatonin’s action on epigenetic regulation in human diseases including neurodegenerative diseases, diabetes, cancer, and cardiovascular diseases. It summarizes the ability of melatonin to act on molecules such as proteins and RNAs which affect the development and progression of diseases.

Nuclear oligo hashing improves differential analysis of single-cell RNA-seq

Single-cell RNA sequencing (scRNA-seq) offers a high-resolution molecular view into complex tissues, but suffers from high levels of technical noise which frustrates efforts to compare the gene expression programs of different cell types. "Spike-in" RNA standards help control for technical variation in scRNA-seq, but using them with recently developed, ultra-scalable scRNA-seq methods based on combinatorial indexing is not feasible. Here, we describe a simple and cost-effective method for normalizing transcript counts and subtracting technical variability that improves differential expression analysis in scRNA-seq. The method affixes a ladder of synthetic single-stranded DNA oligos to each cell that appears in its RNA-seq library. With improved normalization we explore chemical perturbations with broad or highly specific effects on gene regulation, including RNA pol II elongation, histone deacetylation, and activation of the glucocorticoid receptor. Our methods reveal that inhibiting histone deacetylation prevents cells from executing their canonical program of changes following glucocorticoid stimulation.

Developmental and Early Life Origins of Hypertension: Preventive Aspects of Melatonin

Hypertension represents a major disease burden worldwide. Abundant evidence suggests that hypertension can originate in early life. Adverse programming processes can be prevented by early life intervention-namely, reprogramming-to avoid developing chronic diseases later in life. Melatonin is an endogenously produced hormone with a multifaceted biological function. Although melatonin supplementation has shown benefits for human health, less attention has been paid to exploring its reprogramming effects on the early life origins of hypertension. In this review, first, we discuss the physiological roles of melatonin in pregnancy, fetal development, and the regulation of blood pressure. Then, we summarize the epidemiological and experimental evidence for the early life origins of hypertension. This is followed by a description of the animal models used to examine early melatonin therapy as a reprogramming strategy to protect against the early life origins of hypertension. A deeper understanding of the developmental programming of hypertension and recent advances in early melatonin intervention might provide a path forward in reducing the global burden of hypertension.

Melatonin treatment during chronic hypoxic gestation improves neonatal cerebrovascular function

BACKGROUND

Fetal chronic hypoxia is associated with blood flow redistribution and oxidative damage in the brain, leading to increased perinatal morbimortality. Melatonin reduces oxidative stress, improves vascular function, and has neuroprotective effects.

OBJECTIVES

This study aimed to determine the effects of an oral melatonin treatment to pregnant ewes at high-altitude, on the cerebrovascular function of their neonates.

STUDY DESIGN

Ten high-altitude pregnant sheep received either vehicle or melatonin (10 mg/d) during the last third of gestation until delivery. Postnatal daily hemodynamic measurements were recorded from lambs until 12 days old. In addition, lambs were submitted to a graded oxygenation protocol to assess cerebrovascular responses. Subsequently, lambs were euthanized, and middle cerebral arteries (MCA) were collected for vascular function, protein levels, and morphostructural analyses.

RESULTS

Antenatal treatment doubled plasma levels of melatonin in pregnant ewes. Melatonin increased carotid flow and decreased carotid vascular resistance in the lambs by the end of the first week. Furthermore, melatonin increased MCA's maximal vasoconstrictor and vasodilator responses, associated with nitric oxide-dependent and independent mechanisms.

CONCLUSIONS

An oral treatment with melatonin during pregnancy promotes postnatal cerebral perfusion in chronically hypoxic neonates. Melatonin is a potential treatment for cerebrovascular dysfunction due to perinatal chronic hypoxia.

Preventive Aspects of Early Resveratrol Supplementation in Cardiovascular and Kidney Disease of Developmental Origins

The increase in the incidence of cardiovascular diseases (CVDs) and kidney disease has stimulated research for strategies that could prevent, rather than just treat, both interconnected disorders. Resveratrol, a polyphenolic compound with pleiotropic biofunctions, has shown health benefits. Emerging epidemiological data supports that early life environmental insults are regarded as increased risks of developing CVDs and kidney disease in adulthood. Conversely, both disorders could be reversed or postponed by shifting interventions from adulthood to earlier stage by so-called reprogramming. The purpose of this review is first to highlight current epidemiological studies linking cardiovascular and renal programming to resulting CVD and kidney disease of developmental origins. This will be followed by a summary of how resveratrol could exert a positive influence on CVDs and kidney disease. This review also presents an overview of the evidence documenting resveratrol as a reprogramming agent to protect against CVD and kidney disease of developmental origins from animal studies and to outline the advances in understanding the underlying molecular mechanisms. Overall, this review reveals the need for future research to further clarify the reprogramming effects of resveratrol before clinical translation.

Targeting the Renin-Angiotensin-Aldosterone System to Prevent Hypertension and Kidney Disease of Developmental Origins

The renin-angiotensin-aldosterone system (RAAS) is implicated in hypertension and kidney disease. The developing kidney can be programmed by various early-life insults by so-called renal programming, resulting in hypertension and kidney disease in adulthood. This theory is known as developmental origins of health and disease (DOHaD). Conversely, early RAAS-based interventions could reverse program processes to prevent a disease from occurring by so-called reprogramming. In the current review, we mainly summarize (1) the current knowledge on the RAAS implicated in renal programming; (2) current evidence supporting the connections between the aberrant RAAS and other mechanisms behind renal programming, such as oxidative stress, nitric oxide deficiency, epigenetic regulation, and gut microbiota dysbiosis; and (3) an overview of how RAAS-based reprogramming interventions may prevent hypertension and kidney disease of developmental origins. To accelerate the transition of RAAS-based interventions for prevention of hypertension and kidney disease, an extended comprehension of the RAAS implicated in renal programming is needed, as well as a greater focus on further clinical translation.

Melatonin and Cancer: A Polyhedral Network Where the Source Matters

Melatonin is one of the most phylogenetically conserved signals in biology. Although its original function was probably related to its antioxidant capacity, this indoleamine has been “adopted” by multicellular organisms as the “darkness signal” when secreted in a circadian manner and is acutely suppressed by light at night by the pineal gland. However, melatonin is also produced by other tissues, which constitute its extrapineal sources. Apart from its undisputed chronobiotic function, melatonin exerts antioxidant, immunomodulatory, pro-apoptotic, antiproliferative, and anti-angiogenic effects, with all these properties making it a powerful antitumor agent. Indeed, this activity has been demonstrated to be mediated by interfering with various cancer hallmarks, and different epidemiological studies have also linked light at night (melatonin suppression) with a higher incidence of different types of cancer. In 2007, the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption, where melatonin plays a central role. Our aim is to review, from a global perspective, the role of melatonin both from pineal and extrapineal origin, as well as their possible interplay, as an intrinsic factor in the incidence, development, and progression of cancer. Particular emphasis will be placed not only on those mechanisms related to melatonin’s antioxidant nature but also on the recently described novel roles of melatonin in microbiota and epigenetic regulation.

Developmental Programming: Physiological Impacts of Prenatal Melatonin Administration on Reproductive Capacity and Serum Triiodothyronine of Adult Female Offspring Rat Born to Moms Exposed to Bisphenol A During Pregnancy

Gestational bisphenol A (BPA) exposure induced multiple programmed diseases in the adult offsprings. Thus, this study targeted exploring the physiological impacts of melatonin (MEL) as a reprogramming strategy against in utero BPA exposure on reproductive capacity of adult F1 female rat offspring. Forty adult pregnant albino female rats were divided equally into 5 groups (n = 8): group I (control), group II (low-dose BPA; 25 μg BPA/kg B.w.t.), group III (low-dose BPA + 10 mg MEL/kg B.w.t.), group IV (high-dose BPA; 250 μg/kg B.w.t.), and group V (high-dose BPA + MEL). Treatments were given daily by subcutaneous (s/c) injection from the fourth day of pregnancy until full term. After delivery, female offspring were selected, and on postnatal day 60, adult offspring were examined for estrus regularity and then were sacrificed at estrus to collect blood and tissue samples. Findings clarified that in utero BPA exposure (both doses) increased significantly (P < 0.05) the ovarian weights and the serum levels of estrogen but decreased that of triiodothyronine (T3) compared to control groups. Significant increasing of serum malondialdehyde (MDA) and decreasing of total antioxidant capacity (TAC) were also detected. Both doses of BPA disturbed remarkably the estrus cycles and caused marked aberrations in ovarian and uterine tissues. Interestingly, prenatal MEL co-treatment with BPA mitigated significantly all of these degenerative changes. Thus, this study first demonstrated that prenatal MEL therapy could be used as a potent reprogramming intervention against BPA-induced reproductive disorders in the adult F1 female rat offspring.

Pharmacological agents under investigation in the treatment of coronavirus disease 2019 and the importance of melatonin

Coronavirus disease 2019 (COVID‐19) is a life‐threatening infectious respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). COVID‐19 pandemic causing morbidities and even deaths worldwide revealed that there is urgent need to find pharmacological agents or vaccines. Although there are a lot of agents under investigation, there is no approved agent for the prevention or treatment of the COVID‐19 yet. Treatment of patients remains mainly supportive as well as compassionate use of the agents under investigation. It is well established that excessive inflammatory and immune response and oxidative injury play a critical role in the pathogenesis of COVID‐19. In this review, we aimed to update knowledge about pathogenesis, clinical features, and pharmacological treatment of COVID‐19 and review the potential beneficial effects of ancient antioxidant, anti‐inflammatory, and immunomodulatory molecule melatonin for prevention and treatment of COVID‐19.

Neonatal glucocorticoid overexposure alters cardiovascular function in young adult horses in a sex-linked manner

Prenatal glucocorticoid overexposure has been shown to programme adult cardiovascular function in a range of species, but much less is known about the long-term effects of neonatal glucocorticoid overexposure. In horses, prenatal maturation of the hypothalamus-pituitary-adrenal axis and the normal prepartum surge in fetal cortisol occur late in gestation compared to other precocious species. Cortisol levels continue to rise in the hours after birth of full-term foals and increase further in the subsequent days in premature, dysmature and maladapted foals. Thus, this study examined the adult cardiovascular consequences of neonatal cortisol overexposure induced by adrenocorticotropic hormone administration to full-term male and female pony foals. After catheterisation at 2-3 years of age, basal arterial blood pressures (BP) and heart rate were measured together with the responses to phenylephrine (PE) and sodium nitroprusside (SNP). These data were used to assess cardiac baroreflex sensitivity. Neonatal cortisol overexposure reduced both the pressor and bradycardic responses to PE in the young adult males, but not females. It also enhanced the initial hypotensive response to SNP, slowed recovery of BP after infusion and reduced the gain of the cardiac baroreflex in the females, but not males. Basal diastolic pressure and cardiac baroreflex sensitivity also differed with sex, irrespective of neonatal treatment. The results show that there is a window of susceptibility for glucocorticoid programming during the immediate neonatal period that alters cardiovascular function in young adult horses in a sex-linked manner.

Gut Dysbiosis Dysregulates Central and Systemic Homeostasis via Suboptimal Mitochondrial Function: Assessment, Treatment and Classification Implications

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The gut and mitochondria have emerged as two important hubs at the cutting edge of research across a diverse array of medical conditions, including most psychiatric conditions. This article highlights the interaction of the gut and mitochondria over the course of development, with an emphasis on the consequences for transdiagnostic processes across psychiatry, but with relevance to wider medical conditions. As well as raised levels of circulating lipopolysaccharide (LPS) arising from increased gut permeability, the loss of the short-chain fatty acid, butyrate, is an important mediator of how gut dysbiosis modulates mitochondrial function. Reactive cells, central glia and systemic immune cells are also modulated by the gut, in part via impacts on mitochondrial function in these cells. Gut-driven alterations in the activity of reactive cells over the course of development are proposed to be an important determinant of the transdiagnostic influence of glia and the immune system. Stress, including prenatal stress, also acts via the gut. The suppression of butyrate, coupled to raised LPS, drives oxidative and nitrosative stress signalling that culminates in the activation of acidic sphingomyelinase-induced ceramide. Raised ceramide levels negatively regulate mitochondrial function, both directly and via its negative impact on daytime, arousal-promoting orexin and night-time sleep-promoting pineal gland-derived melatonin. Both orexin and melatonin positively regulate mitochondria oxidative phosphorylation. Consequently, gut-mediated increases in ceramide have impacts on the circadian rhythm and the circadian regulation of mitochondrial function. Butyrate, orexin and melatonin can positively regulate mitochondria via the disinhibition of the pyruvate dehydrogenase complex, leading to increased conversion of pyruvate to acetyl- CoA. Acetyl-CoA is a necessary co-substrate for the initiation of the melatonergic pathway in mitochondria and therefore the beneficial effects of mitochondria melatonin synthesis on mitochondrial function. This has a number of treatment implications across psychiatric and wider medical conditions, including the utilization of sodium butyrate and melatonin.

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Overall, gut dysbiosis and increased gut permeability have significant impacts on central and systemic homeostasis via the regulation of mitochondrial function, especially in central glia and systemic immune cells.

The Role of Prenatal Melatonin in the Regulation of Childhood Obesity

There is a growing awareness that pregnancy can set the foundations for an array of diverse medical conditions in the offspring, including obesity. A wide assortment of factors, including genetic, epigenetic, lifestyle, and diet can influence foetal outcomes. This article reviews the role of melatonin in the prenatal modulation of offspring obesity. A growing number of studies show that many prenatal risk factors for poor foetal metabolic outcomes, including gestational diabetes and night-shift work, are associated with a decrease in pineal gland-derived melatonin and associated alterations in the circadian rhythm. An important aspect of circadian melatonin’s effects is mediated via the circadian gene, BMAL1, including in the regulation of mitochondrial metabolism and the mitochondrial melatoninergic pathway. Alterations in the regulation of mitochondrial metabolic shifts between glycolysis and oxidative phosphorylation in immune and glia cells seem crucial to a host of human medical conditions, including in the development of obesity and the association of obesity with the risk of other medical conditions. The gut microbiome is another important hub in the pathoetiology and pathophysiology of many medical conditions, with negative consequences mediated by a decrease in the short-chain fatty acid, butyrate. The effects of butyrate are partly mediated via an increase in the melatoninergic pathway, indicating interactions of the gut microbiome with melatonin. Some of the effects of melatonin seem mediated via the alpha 7 nicotinic receptor, whilst both melatonin and butyrate may regulate obesity through the opioidergic system. Oxytocin, a recently recognized inhibitor of obesity, may also be acting via the opioidergic system. The early developmental regulation of these processes and factors by melatonin are crucial to the development of obesity and many diverse comorbidities.

The Role of DNMT and HDACs in the Fetal Programming of Hypertension by Glucocorticoids

The causes of hypertension are complex and involve both genetic and environmental factors. Environment changes during fetal development have been linked to adult diseases including hypertension. Studies show that timed in utero exposure to the synthetic glucocorticoid (GC) dexamethasone (Dex) results in the development of hypertension in adult rats. Evidence suggests that in utero stress can alter patterns of gene expression, possibly a result of alterations in the topology of the genome by epigenetic markers such as DNA methyltransferases (DNMTs) and histone deacetylases (HDACs). The objective of this study was to determine the effects of epigenetic regulators in the fetal programming and the development of adult hypertension. Specifically, this research examined the effects of the HDAC inhibitor valproic acid (VPA) and the DNMT inhibitor 5-aza-2′-deoxycytidine (5aza2DC) on blood pressure (BP) and gene expression in prenatal Dex-programmed rats. Data suggest that both VPA and 5aza2DC attenuated the Dex-mediated development of hypertension and restored BP to control levels. Epigenetic DNMT inhibition (DNMTi) or HDAC inhibition (HDACi) also successfully attenuated elevations in the majority of altered catecholamine (CA) enzyme expression, phenylethanolamine N-methyltransferase (PNMT) protein, and elevated epinephrine (Epi) levels in males. Although females responded to HDACi similar to males, DNMTi drove increased glucocorticoid receptor (GR) and PNMT expression and elevations in circulating Epi in females despite showing normotensive BP.

Light and Circadian Signaling Pathway in Pregnancy: Programming of Adult Health and Disease

Light is a crucial environmental signal that affects elements of human health, including the entrainment of circadian rhythms. A suboptimal environment during pregnancy can increase the risk of offspring developing a wide range of chronic diseases in later life. Circadian rhythm disruption in pregnant women may have deleterious consequences for their progeny. In the modern world, maternal chronodisruption can be caused by shift work, jet travel across time zones, mistimed eating, and excessive artificial light exposure at night. However, the impact of maternal chronodisruption on the developmental programming of various chronic diseases remains largely unknown. In this review, we outline the impact of light, the circadian clock, and circadian signaling pathways in pregnancy and fetal development. Additionally, we show how to induce maternal chronodisruption in animal models, examine emerging research demonstrating long-term negative implications for offspring health following maternal chronodisruption, and summarize current evidence related to light and circadian signaling pathway targeted therapies in pregnancy to prevent the development of chronic diseases in offspring.

Perinatal Use of Melatonin for Offspring Health: Focus on Cardiovascular and Neurological Diseases

Cardiovascular and neurological diseases can originate in early life. Melatonin, a biologically active substance, acts as a pleiotropic hormone essential for pregnancy and fetal development. Maternal melatonin can easily pass the placenta and provide photoperiodic signals to the fetus. Though melatonin uses in pregnant or lactating women have not yet been recommended, there is a growing body of evidence from animal studies in support of melatonin as a reprogramming strategy to prevent the developmental programming of cardiovascular and neurological diseases. Here, we review several key themes in melatonin use in pregnancy and lactation within offspring health and disease. We have particularly focused on the following areas: the pathophysiological roles of melatonin in pregnancy, lactation, and fetal development; clinical uses of melatonin in fetal and neonatal diseases; experimental evidence supporting melatonin as a reprogramming therapy to prevent cardiovascular and neurological diseases; and reprogramming mechanisms of melatonin within developmental programming. The targeting of melatonin uses in pregnancy and lactation will be valuable in the prevention of various adult chronic diseases in later life, and especially cardiovascular and neurological diseases.

Transcriptional dysregulation by a nucleus-localized aminoacyl-tRNA synthetase associated with Charcot-Marie-Tooth neuropathy

Charcot-Marie-Tooth disease (CMT) is a length-dependent peripheral neuropathy. The aminoacyl-tRNA synthetases constitute the largest protein family implicated in CMT. Aminoacyl-tRNA synthetases are predominantly cytoplasmic, but are also present in the nucleus. Here we show that a nuclear function of tyrosyl-tRNA synthetase (TyrRS) is implicated in a Drosophila model of CMT. CMT-causing mutations in TyrRS induce unique conformational changes, which confer capacity for aberrant interactions with transcriptional regulators in the nucleus, leading to transcription factor E2F1 hyperactivation. Using neuronal tissues, we reveal a broad transcriptional regulation network associated with wild-type TyrRS expression, which is disturbed when a CMT-mutant is expressed. Pharmacological inhibition of TyrRS nuclear entry with embelin reduces, whereas genetic nuclear exclusion of mutant TyrRS prevents hallmark phenotypes of CMT in the Drosophila model. These data highlight that this translation factor may contribute to transcriptional regulation in neurons, and suggest a therapeutic strategy for CMT.

Tyrosyl-tRNA synthetase (TyrRS) is a translation factor and predominantly cytoplasmic, but can also be found in the nucleus. Here authors show using a fly model of Charcot-Marie-Tooth (CMT) disease that nuclear localization of mutant TyrRS contributes to the CMT-like phenotype.

Decreased H3K9 acetylation level of LXRα mediated dexamethasone-induced placental cholesterol transport dysfunction

Due to the insufficient fetal cholesterol synthesis, maternal cholesterol transport through the placenta becomes an important source of fetal cholesterol pool, which is essential for fetal growth and development. This study aimed to investigate the effects of dexamethasone on fetal cholesterol levels, and explore its placental mechanism. Pregnant Wistar rats were injected subcutaneously with dexamethasone (0.8 mg/kg·d) from gestational day 9 to 20. Results showed that dexamethasone increased maternal serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C) levels, as well as placental cholesterol synthesis and TC concentration, while reduced fetal birth weight, and serum TC, HDL-C and LDL-C levels. Meanwhile, the expression of placental cholesterol transporters, including low-density lipoprotein receptor (LDLR), scavenger receptor class B type I (SR-B1) and ATP-binding cassette transporter A1 and G1 (ABCA1 and ABCG1) were decreased by dexamethasone. Furthermore, the expression of glucocorticoid receptor (GR) and histone deacetylase 3 (HDAC3) were increased, while the H3K9ac and expression levels of liver X receptor α (LXRα) promoter were reduced. In human trophoblast cell line (BeWo), dexamethasone concentration-dependently decreased the expression levels of LDLR, SR-B1, ABCA1, ABCG1 as well as LXRα. Dexamethasone (2500 nM) induced GR translocation into nucleus and recruited HDAC3. Furthermore, LXRα agonist and GR inhibitor reversed respectively dexamethasone-induced the expression inhibitions of cholesterol transporter and LXRα, and HDAC3 siRNA reversed the H3K9ac level of LXRα promoter and its expression. Together, dexamethasone impaired placental cholesterol transport and eventually decreased fetal cholesterol levels, which is related to the down-regulation of LXRα mediated by GR/HDAC3/H3K9ac signaling.

Antenatal melatonin modulates an enhanced antioxidant/pro-oxidant ratio in pulmonary hypertensive newborn sheep

Chronic hypobaric hypoxia during fetal and neonatal life induces neonatal pulmonary hypertension. Hypoxia and oxidative stress are driving this condition, which implies an increase generation of reactive oxygen species (ROS) and/or decreased antioxidant capacity. Melatonin has antioxidant properties that decrease oxidative stress and improves pulmonary vascular function when administered postnatally. However, the effects of an antenatal treatment with melatonin in the neonatal pulmonary function and oxidative status are unknown. Therefore, we hypothesized that an antenatal therapy with melatonin improves the pulmonary arterial pressure and antioxidant status in high altitude pulmonary hypertensive neonates. Twelve ewes were bred at high altitude (3600 m); 6 of them were used as a control group (vehicle 1.4% ethanol) and 6 as a melatonin treated group (10 mg d-1 melatonin in vehicle). Treatments were given once daily during the last third of gestation (100-150 days). Lambs were born and raised with their mothers until 12 days old, and neonatal pulmonary arterial pressure and resistance, plasma antioxidant capacity and the lung oxidative status were determined. Furthermore, we measured the pulmonary expression and activity for the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase, and the oxidative stress markers 8-isoprostanes, 4HNE and nitrotyrosine. Finally, we assessed pulmonary pro-oxidant sources by the expression and function of NADPH oxidase, mitochondria and xanthine oxidase. Melatonin decreased the birth weight. However, melatonin enhanced the plasma antioxidant capacity and decreased the pulmonary antioxidant activity, associated with a diminished oxidative stress during postnatal life. Interestingly, melatonin also decreased ROS generation at the main pro-oxidant sources. Our findings suggest that antenatal administration of melatonin programs an enhanced antioxidant/pro-oxidant status, modulating ROS sources in the postnatal lung.

Melatonin as a Hormone: New Physiological and Clinical Insights

Melatonin is a ubiquitous molecule present in almost every live being from bacteria to humans. In vertebrates, besides being produced in peripheral tissues and acting as an autocrine and paracrine signal, melatonin is centrally synthetized by a neuroendocrine organ, the pineal gland. Independently of the considered species, pineal hormone melatonin is always produced during the night and its production and secretory episode duration are directly dependent on the length of the night. As its production is tightly linked to the light/dark cycle, melatonin main hormonal systemic integrative action is to coordinate behavioral and physiological adaptations to the environmental geophysical day and season. The circadian signal is dependent on its daily production regularity, on the contrast between day and night concentrations, and on specially developed ways of action. During its daily secretory episode, melatonin coordinates the night adaptive physiology through immediate effects and primes the day adaptive responses through prospective effects that will only appear at daytime, when melatonin is absent. Similarly, the annual history of the daily melatonin secretory episode duration primes the central nervous/endocrine system to the seasons to come. Remarkably, maternal melatonin programs the fetuses' behavior and physiology to cope with the environmental light/dark cycle and season after birth. These unique ways of action turn melatonin into a biological time-domain-acting molecule. The present review focuses on the above considerations, proposes a putative classification of clinical melatonin dysfunctions, and discusses general guidelines to the therapeutic use of melatonin.

The effect of melatonin on cardio fibrosis in juvenile rats with pressure overload and deregulation of HDACs

The effect of melatonin on juveniles with cardio fibrosis is poorly understood. We investigated whether HDACs participate in the anti-fibrotic processes regulated by melatonin during hypertrophic remodeling. Abdominal aortic constriction (AAC) was employed in juvenile rats resulting in pressure overload-induced ventricular hypertrophy and melatonin was subsequently decreased via continuous light exposure for 5 weeks after surgery. AAC rats displayed an increased cross-sectional area of myocardial fibers and significantly elevated collagen deposition compared to sham-operated rats, as measured by HE and Masson Trichrome staining. Continuous light exposure following surgery exacerbated the increase in the cross-sectional area of myocardial fibers. The expression of HDAC1, HDAC2, HDAC3, HDAC4 and HDAC6 genes were all significantly enhanced in AAC rats with light exposure relative to the other rats. Moreover, the protein level of TNF-α was also upregulated in the AAC light exposure groups when compared with the sham. However, Smad4 protein expression was unchanged in the juveniles' hearts. In contrast, beginning 5 weeks after the operation, the AAC rats were treated with melatonin (10 mg/kg, intraperitoneal injection every evening) or vehicle 4 weeks, and sham rats were given vehicle. The changes in the histological measures of cardio fibrosis and the gene expressions of HDAC1, HDAC2, HDAC3, HDAC4 and HDAC6 were attenuated by melatonin administration. The results reveal that melatonin plays a role in the development of cardio fibrosis and the expression of HDAC1, HDAC2, HDAC3, HDAC4 and HDAC6 in cardiomyocytes.

Maternal Melatonin Therapy Attenuates Methyl-Donor Diet-Induced Programmed Hypertension in Male Adult Rat Offspring

Although pregnant women are advised to consume methyl-donor food, some reports suggest an adverse outcome. We investigated whether maternal melatonin therapy can prevent hypertension induced by a high methyl-donor diet. Female Sprague-Dawley rats received either a normal diet, a methyl-deficient diet (L-MD), or a high methyl-donor diet (H-MD) during gestation and lactation. Male offspring were assigned to four groups (n = 7⁻8/group): control, L-MD, H-MD, and H-MD rats were given melatonin (100 mg/L) with their drinking water throughout the period of pregnancy and lactation (H-MD+M). At 12 weeks of age, male offspring exposed to a L-MD or a H-MD diet developed programmed hypertension. Maternal melatonin therapy attenuated high methyl-donor diet-induced programmed hypertension. A maternal L-MD diet and H-MD diet caused respectively 938 and 806 renal transcripts to be modified in adult offspring. The protective effects of melatonin against programmed hypertension relate to reduced oxidative stress, increased urinary NO₂^- level, and reduced renal expression of sodium transporters. A H-MD or L-MD diet may upset the balance of methylation status, leading to alterations of renal transcriptome and programmed hypertension. A better understanding of reprogramming effects of melatonin might aid in developing a therapeutic strategy for the prevention of hypertension in adult offspring exposed to an excessive maternal methyl-supplemented diet.

Preventing childhood and lifelong disability: Maternal dietary supplementation for perinatal brain injury

The majority of brain injuries that lead to cerebral palsy, developmental disability, and mental health disorders have their onset in utero. These lifelong conditions come with great economic and emotional burden as they impact function in nearly all domains of affected individuals' lives. Unfortunately, current therapeutic options are limited. There remains a focus on rescue, rehabilitation, and regeneration after the injury has occurred, rather than aiming to prevent the initial injury. Prevention would imply treating the mother during pregnancy to alter the fetal environment and in turn, treat the fetus. Fear of harming the developing fetus remains as a result of errors of the past such as the release of thalidomide. In this review, we outline evidence from animal studies and clinical trials that have explored maternal dietary supplementation with natural health products (including nutraceuticals and functional foods) for perinatal brain injury prevention. Namely, we discuss magnesium sulphate, creatine, choline, melatonin, resveratrol and broccoli sprouts/sulforaphane. Although clinical trials have only been completed in this realm for magnesium sulphate, results in animal models have been promising, suggesting that this is a productive avenue for further research. Natural health products may provide safe, effective, affordable, and easily accessible prevention of fetal brain injury and resulting lifelong disabilities.

The environmental neurotoxin β-N-methylamino-L-alanine inhibits melatonin synthesis in primary pinealocytes and a rat model

The environmental neurotoxin β-N-methylamino-L-alanine (BMAA) is a glutamate receptor agonist that can induce oxidative stress and has been implicated as a possible risk factor for neurodegenerative disease. Detection of BMAA in mussels, crustaceans, and fish illustrates that the sources of human exposure to this toxin are more abundant than previously anticipated. The aim of this study was to determine uptake of BMAA in the pineal gland and subsequent effects on melatonin production in primary pinealocyte cultures and a rat model. Autoradiographic imaging of 10-day-old male rats revealed a high and selective uptake in the pineal gland at 30 minutes to 24 hours after ¹⁴ C-L-BMAA administration (0.68 mg/kg). Primary pinealocyte cultures exposed to 0.05-3 mmol/L BMAA showed a 57%-93% decrease in melatonin synthesis in vitro. Both the metabotropic glutamate receptor 3 (mGluR3) antagonist Ly341495 and the protein kinase C (PKC) activator phorbol-12-myristate-13-acetate prevented the decrease in melatonin secretion, suggesting that BMAA inhibits melatonin synthesis by mGluR3 activation and PKC inhibition. Serum analysis revealed a 45% decrease in melatonin concentration in neonatal rats assessed 2 weeks after BMAA administration (460 mg/kg) and confirmed an inhibition of melatonin synthesis in vivo. Given that melatonin is a most important neuroprotective molecule in the brain, the etiology of BMAA-induced neurodegeneration may include mechanisms beyond direct excitotoxicity and oxidative stress.

Maternal melatonin or agomelatine therapy prevents programmed hypertension in male offspring of mother exposed to continuous light

Hypertension can originate from early-life insults, whereas maternal melatonin therapy can be protective in a variety of models of programmed hypertension. We hypothesize that melatonin or melatonin receptor agonist agomelatine can prevent programmed hypertension in adult offspring induced by maternal exposure to continuous light. Female Sprague-Dawley pregnant rats randomly divided into four groups: controls, rats exposed to continuous light, exposed to continuous light plus treated with agomelatine (50 mg/day i.p.), and exposed to continuous light plus treated with 0.01% melatonin in drinking water throughout pregnancy and lactation period. Male offspring (n = 10/group) from three litters were examined at 12 weeks of age. Maternal continuous light exposure-induced hypertension in male offspring, which was prevented by melatonin or agomelatine therapy. Continuous light exposure did not affect melatonin pathway in adult offspring kidney. Genes that belong to the renin-angiotensin system (RAS), sodium transporters, AMP-activated protein kinase pathway, and circadian rhythm were potentially involved in the maternal exposure to continuous light-induced programmed hypertension. Maternal agomelatine therapy decreased Ace expression but increased Agtr2 and Mas1. Maternal melatonin therapy prevented the increases of Slc9a3, Slc12a3, and Atp1a1 expression induced by maternal continuous light exposure. In conclusion, maternal melatonin or agomelatine therapy prevents programmed hypertension induced by maternal exposure to continuous light. Agomelatine and melatonin reprogram the RAS and sodium transporters differentially, to prevent negative programming of continuous light. Our data highlight candidate genes and pathways in renal programming as targets for therapeutic approaches to prevent programmed hypertension caused by early-life disturbance of the circadian rhythm.

Postnatal high-fat diet sex-specifically exacerbates prenatal dexamethasone-induced hypertension: Mass spectrometry-based quantitative proteomic approach

Hypertension can originate from pre- and post-natal insults. High-fat (HF) diet and prenatal dexamethasone (DEX) exposure are both involved in hypertension of developmental origins. We examined whether postnatal HF diet sex-specifically increases the vulnerability to prenatal DEX exposure-induced programmed hypertension in adult offspring. Additionally, we sought to identify candidate proteins involved in programmed hypertension through a mass spectrometry-based quantitative proteomic approach. Male and female offspring were studied separately: control, DEX, HF, and DEX + HF (n=8/group). Pregnant Sprague-Dawley rats received dexamethasone (0.1 mg/kg body weight) or vesicle from gestational day 16-22. Offspring received high-fat diet (D12331, Research Diets) or regular diet from weaning to 4 months of age. Rats were sacrificed at 4 months of age. We found that postnatal HF diet increased vulnerability of prenatal DEX-induced hypertension in male but not in female adult offspring. Additionally, HF and DEX elicited renal programming in a sex-specific fashion. In males, DEX + HF increased renal parvalbumin (PVALB) and carbonic anhydrase III (CA III) protein levels. While prenatal DEX down-regulated PVALB and CA III protein abundance in female offspring kidneys. Moreover, DEX + HF increased renal protein level of type 3 sodium hydrogen exchanger (NHE3) in males but not in females. In conclusion, postnatal HF diet and prenatal DEX exposure synergistically induced programmed hypertension in male-only offspring. DEX + HF induced sex-specific alterations of protein profiles in offspring kidneys. By identifying candidate proteins underlying sex-specific mechanisms, our results could lead to novel offspring sex-specific interventions to prevent hypertension induced by antenatal corticosteroids and postnatal HF intake in both sexes.

Biochemical basis for pharmacological intervention as a reprogramming strategy against hypertension and kidney disease of developmental origin

The concept of "developmental origins of health and disease" (DOHaD) stipulates that both hypertension and kidney disease may take origin from early-life insults. The DOHaD concept also offers reprogramming strategies aiming at shifting therapeutic interventions from adulthood to early life, even before clinical symptoms are evident. Based on those two concepts, this review will present the evidence for the existence of, and the programming mechanisms in, kidney developmental programming that may lead to hypertension and kidney disease. This will be followed by potential pharmacological interventions that may serve as a reprogramming strategy to counter the rising epidemic of hypertension and kidney disease. We point out that before patients could benefit from this strategy, the most pressing issue is for the growing body of evidence from animal studies in support of pharmacological intervention as a reprogramming strategy to long-term protect against hypertension and kidney disease of developmental origins to be validated clinically and the critical window, drug dose, dosing regimen, and therapeutic duration identified.

SIRT1 increases cardiomyocyte binucleation in the heart development

SIRT1 regulates cell senescence. We investigated a novel role of SIRT1 in the regulation of cardiomyocyte terminal differentiation in the developing heart. Retinoic acid (RA)-induced binucleation of H9c2 cells was associated with increased SIRT1 expression. Inhibition of SIRT1 activity or expression significantly decreased RA-induced binucleation. SIRT1 expression was minimal in the fetal heart and significantly upregulated in the hearts of postnatal day 7 (P7) rat pups. In contrast, heart-specific miR-133a expression was high in the fetal heart but significantly reduced in P7 pup hearts. The miR-133a promoter contains a canonical HRE element and hypoxia upregulated miR-133a gene expression in the heart. SIRT1 mRNA 3′UTR has miR-133a binding sequences and miR-133a and hypoxia suppressed SIRT1 expression in cardiomyocytes. Of importance, inhibition of SIRT1 significantly reduced binucleated cardiomyocytes in the hearts of P7 pups. Taken together, the present study reveals a novel role of SIRT1 and its regulation by miR-133a in cardiomyocyte terminal differentiation of the developing heart, and suggests a potential therapeutic strategy that may impact cardiac function later in life.

Role of the histone deacetylase inhibitor valproic acid in high-fat diet-induced hypertension via inhibition of HDAC1/angiotensin II axis

BACKGROUND

Obesity is known as an epidemic worldwide because of consumption of westernized high-fat diets and one of the major risk factors of hypertension. Histone deacetylases (HDACs) control gene expression by regulating histone/non-histone protein deacetylation. HDAC inhibitors exert anti-cancer and anti-inflammatory effects and play a protective role in cardiovascular diseases. In the present study, we tested the effect of an FDA-approved pan-HDAC inhibitor valproic acid (VPA) on high-fat diet (HFD)-induced hypertension in mice. Furthermore, we examined the mechanism of VPA-induced prevention of hypertension.

METHODS

Nine-week-old male C57BL/6 mice were fed either a normal diet (ND) or HFD. When the HFD group reached a pre-hypertensive phase (130-140 mm Hg systolic blood pressure), VPA was administered for 6 days (300 mg kg^-1 per day). Body weights and blood pressure (BP), expression of renin-angiotensin system (RAS) components and HDAC1 were determined. The direct role of HDAC1 in the expression of RAS components was investigated using gene silencing.

RESULTS

HFD accelerated the increase in body weight from 22.4±1.3 to 31.9±3.0 compared to in the ND group from 22.7±0.9 to 26.0±1.7 (P=0.0134 ND vs HFD), systolic BP from 118.5±5.7 to 145.0±3.0 (P<0.001), and diastolic BP from 91.0±13.6 to 121.0±5.0 (P=0.006); BP was not altered in the ND group. HFD increased RAS components and HDAC1 in the kidneys as well as leptin in the plasma. VPA administration prevented the progression of hypertension and inhibited the increase in expression of HDAC1 and RAS components. VPA did not affect plasma leptin level. Knockdown of HDAC1 in MDCK cells decreased the expression of angiotensinogen and type 1 angiotensin II receptor.

CONCLUSIONS

VPA prevented HFD-induced hypertension by downregulating angiotensin II and its receptor via inhibition of HDAC1, offering a novel therapeutic option for HFD-induced hypertension.

Resveratrol prevents the combined maternal plus postweaning high-fat-diets-induced hypertension in male offspring

Maternal high-fat (HF) diet is believed to induce oxidative stress and activate nutrient-sensing signals, which increase the risk of adult offspring to develop hypertension. We investigated whether resveratrol prevents the combined maternal plus postweaning HF-diets-induced hypertension in adult male offspring, with a focus on the kidney. Female Sprague-Dawley rats received either a normal diet (ND) or HF diet (D12331, Research Diets) for 5 weeks before mating and during gestation and lactation. The male offspring were placed on either the ND or HF diet from weaning to 4 months of age, resulting in four experimental groups (maternal diet/postweaning diet; n=8-10/group): ND/ND, ND/HF, HF/ND and HF/HF. Another group of HF/HF rats (n=10) was treated with 0.5% resveratrol in drinking water between 2 and 4 months of age (HF/HF+R). Rats were killed at 4 months of age. We found that HF/HF-induced hypertension in adult offspring was prevented by resveratrol. Resveratrol mediated its protective effect on HF/HF-induced hypertension in the kidneys of male offspring by diminishing oxidative stress; reducing renal asymmetric dimethylarginine levels; mediating the renin-angiotensin system (RAS) in favor of vasodilatation; restoring nutrient-sensing pathways via increased levels of silent information regulator transcript 1 (SIRT1), AMP-activated protein kinase 2α and peroxisome proliferator-activated receptor gamma coactivator 1-α; and inducing autophagy. Our data implicated an association between oxidative stress, RAS, nitric oxide, and nutrient-sensing signals in HF/HF-induced hypertension. Resveratrol, acting as an antioxidant as well as a SIRT1 activator, might be a therapeutic approach for hypertension.

Developmental Programming of Adult Disease: Reprogramming by Melatonin?

Adult-onset chronic non-communicable diseases (NCDs) can originate from early life through so-called the "developmental origins of health and disease" (DOHaD) or "developmental programming". The DOHaD concept offers the "reprogramming" strategy to shift the treatment from adulthood to early life, before clinical disease is apparent. Melatonin, an endogenous indoleamine produced by the pineal gland, has pleiotropic bioactivities those are beneficial in a variety of human diseases. Emerging evidence support that melatonin is closely inter-related to other proposed mechanisms contributing to the developmental programming of a variety of chronic NCDs. Recent animal studies have begun to unravel the multifunctional roles of melatonin in many experimental models of developmental programming. Even though some progress has been made in research on melatonin as a reprogramming strategy to prevent DOHaD-related NCDs, future human studies should aim at filling the translational gap between animal models and clinical trials. Here, we review several key themes on the reprogramming effects of melatonin in DOHaD research. We have particularly focused on the following areas: mechanisms of developmental programming; the interrelationship between melatonin and mechanisms underlying developmental programming; pathophysiological roles of melatonin in pregnancy and fetal development; and insight provided by animal models to support melatonin as a reprogramming therapy. Rates of NCDs are increasing faster than anticipated all over the world. Hence, there is an urgent need to understand reprogramming mechanisms of melatonin and to translate experimental research into clinical practice for halting a growing list of DOHaD-related NCDs.

Developmental Origins of Chronic Kidney Disease: Should We Focus on Early Life?

Chronic kidney disease (CKD) is becoming a global burden, despite recent advances in management. CKD can begin in early life by so-called "developmental programming" or "developmental origins of health and disease" (DOHaD). Early-life insults cause structural and functional changes in the developing kidney, which is called renal programming. Epidemiological and experimental evidence supports the proposition that early-life adverse events lead to renal programming and make subjects vulnerable to developing CKD and its comorbidities in later life. In addition to low nephron endowment, several mechanisms have been proposed for renal programming. The DOHaD concept opens a new window to offset the programming process in early life to prevent the development of adult kidney disease, namely reprogramming. Here, we review the key themes on the developmental origins of CKD. We have particularly focused on the following areas: evidence from human studies support fetal programming of kidney disease; insight from animal models of renal programming; hypothetical mechanisms of renal programming; alterations of renal transcriptome in response to early-life insults; and the application of reprogramming interventions to prevent the programming of kidney disease.

Pregnancy as a critical window for blood pressure regulation in mother and child: programming and reprogramming

Pregnancy is a critical time for long-term blood pressure regulation in both mother and child. Pregnancies complicated by placental insufficiency, resulting in pre-eclampsia and intrauterine growth restriction, are associated with a threefold increased risk of the mother to develop hypertension later in life. In addition, these complications create an adverse intrauterine environment, which programmes the foetus and the second generation to develop hypertension in adult life. Female offspring born to a pregnancy complicated by placental insufficiency are at risk for pregnancy complications during their own pregnancies as well, resulting in a vicious circle with programmed risk for hypertension passing from generation to generation. Here, we review the epidemiology and mechanisms leading to the altered programming of blood pressure trajectories after pregnancies complicated by placental insufficiency. Although the underlying mechanisms leading to hypertension remain the subject of investigation, several abnormalities in angiotensin sensitivity, sodium handling, sympathetic activity, endothelial function and metabolic pathways are found in the mother after exposure to placental insufficiency. In the child, epigenetic modifications and disrupted organ development play a crucial role in programming of hypertension. We emphasize that pregnancy can be viewed as a window of opportunity to improve long-term cardiovascular health of both mother and child, and outline potential gains expected of improved preconceptional, perinatal and post-natal care to reduce the development of hypertension and the burden of cardiovascular disease later in life. Perinatal therapies aimed at reprogramming hypertension are a promising strategy to break the vicious circle of intergenerational programming of hypertension.

Mechanisms of Melatonin in Alleviating Alzheimer's Disease

Alzheimer's disease (AD) is a chronic, progressive and prevalent neurodegenerative disease characterized by the loss of higher cognitive functions and an associated loss of memory. The thus far "incurable" stigma for AD prevails because of variations in the success rates of different treatment protocols in animal and human studies. Among the classical hypotheses explaining AD pathogenesis, the amyloid hypothesis is currently being targeted for drug development. The underlying concept is to prevent the formation of these neurotoxic peptides which play a central role in AD pathology and trigger a multispectral cascade of neurodegenerative processes post-aggregation. This could possibly be achieved by pharmacological inhibition of β- or γ-secretase or stimulating the nonamyloidogenic α-secretase. Melatonin the pineal hormone is a multifunctioning indoleamine. Production of this amphiphilic molecule diminishes with advancing age and this decrease runs parallel with the progression of AD which itself explains the potential benefits of melatonin in line of development and devastating consequences of the disease progression. Our recent studies have revealed a novel mechanism by which melatonin stimulates the nonamyloidogenic processing and inhibits the amyloidogenic processing of β-amyloid precursor protein (βAPP) by stimulating α -secretases and consequently down regulating both β- and γ-secretases at the transcriptional level. In this review, we discuss and evaluate the neuroprotective functions of melatonin in AD pathogenesis, including its role in the classical hypotheses in cellular and animal models and clinical interventions in AD patients, and suggest that with early detection, melatonin treatment is qualified to be an anti-AD therapy.

Targeting on Asymmetric Dimethylarginine-Related Nitric Oxide-Reactive Oxygen Species Imbalance to Reprogram the Development of Hypertension

Adult-onset diseases, including hypertension, can originate from early life, known as the developmental origins of health and disease (DOHaD). Because the developing kidney is vulnerable to early-life insults, renal programming is considered key in the developmental programming of hypertension. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide (NO) synthase inhibitor, can regulate the NO–reactive oxygen species (ROS) balance, and is involved in the development of hypertension. Reprogramming interventions aimed at NO-ROS balance can be protective in both genetic and developmentally programmed hypertension. Here we review several emergent themes of the DOHaD approach regarding the impact of ADMA-related NO-ROS imbalance on programmed hypertension. We focus on the kidney in the following areas: mechanistic insights to interpret programmed hypertension; the impact of ADMA-related NO-ROS imbalance in both genetic and acquired animal models of hypertension; alterations of the renal transcriptome in response to ADMA in the developing kidney; and reprogramming strategies targeting ADMA-related NO-ROS balance to prevent programmed hypertension.

Early postnatal treatment with soluble epoxide hydrolase inhibitor or 15-deoxy-Δ(12,14)-prostagandin J2 prevents prenatal dexamethasone and postnatal high saturated fat diet induced programmed hypertension in adult rat offspring

Prenatal dexamethasone (DEX) exposure, postnatal high-fat (HF) intake, and arachidonic acid pathway are closely related to hypertension. We tested whether a soluble epoxide hydrolase (SEH) inhibitor, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) or 15-deoxy-Δ(12,14)-prostagandin J2 (15dPGJ2) therapy can rescue programmed hypertension in the DEX+HF two-hit model. Four groups of Sprague Dawley rats were studied: control, DEX+HF, AUDA, and 15dPGJ2. Dexamethasone (0.1mg/kg body weight) was intraperitoneally administered to pregnant rats from gestational day 16-22. Male offspring received high-fat diet (D12331, Research Diets) from weaning to 4 months of age. In AUDA group, mother rats received 25mg/L in drinking water during lactation. In the 15dPGJ2 group, male offspring received 15dPGJ2 1.5mg/kg BW by subcutaneous injection once daily for 1 week after birth. We found postnatal HF diet aggravated prenatal DEX-induced programmed hypertension, which was similarly prevented by early treatment with AUDA or 15dPGJ2. The beneficial effects of AUDA and 15d-PGJ2 therapy include inhibition of SEH, increases of renal angiotensin converting enzyme-2 (ACE2) and angiotensin II type 2 receptor (AT2R) protein levels, and restoration of nitric oxide bioavailability. Better understanding of the impact of arachidonic acid pathway in the two-hit model will help prevent programmed hypertension in children exposed to corticosteroids and postnatal HF intake.

Postnatal dexamethasone-induced programmed hypertension is related to the regulation of melatonin and its receptors

Adulthood hypertension can be programmed by glucocorticoid exposure in early life. We found that maternal melatonin therapy prevents postnatal dexamethasone (DEX)-induced programmed hypertension. Melatonin acts through specific receptors, including MT1 and MT2 membrane receptors, and retinoid related orphan nuclear receptors of the RZR/ROR family. Thus we tested whether postnatal DEX-induced hypertension is related to changes of melatonin receptors in the kidney and heart, which was preserved by maternal melatonin therapy. Male neonates were assigned to four groups (n=6-8/group): control, DEX, control+melatonin (MEL), and DEX+MEL. Male rat pups were injected i.p. with DEX on d 1 (0.5 mg/kg BW), d 2 (0.3 mg/kg BW), and d 3 (0.1 mg/kg BW) after birth. Melatonin was administered in drinking water (0.01%) during the lactation period. We found DEX group developed hypertension at 16 weeks of age, which melatonin therapy prevented. Postnatal DEX treatment increased mRNA expression of MT1 and MT2, while decreased RORα and RZRβ in the kidney. These changes were prevented by melatonin therapy. Postnatal DEX decreased protein level of MT2 in the kidney, which was attenuated by melatonin therapy. Renal protein level of RORα was higher in DEX+MEL group compared to control and DEX group. Renal melatonin level was higher in the MEL and DEX+MEL groups compared to control. We concluded that melatonin therapy has long-term protection on postnatal DEX-induced programmed hypertension, which is associated with regulation on melatonin receptors in the kidney. Our findings would offer potential therapeutic approaches to prevent programmed hypertension in premature baby receiving glucocorticoids.

Reprogramming: A Preventive Strategy in Hypertension Focusing on the Kidney

Adulthood hypertension can be programmed in response to a suboptimal environment in early life. However, developmental plasticity also implies that one can prevent hypertension in adult life by administrating appropriate compounds during early development. We have termed this reprogramming. While the risk of hypertension has been assessed in many mother-child cohorts of human developmental programming, interventions necessary to prove causation and provide a reprogramming strategy are lacking. Since the developing kidney is particularly vulnerable to environmental insults and blood pressure is determined by kidney function, renal programming is considered key in developmental programming of hypertension. Common pathways, whereby both genetic and acquired developmental programming converge into the same phenotype, have been recognized. For instance, the same reprogramming interventions aimed at shifting nitric oxide (NO)-reactive oxygen species (ROS) balance, such as perinatal citrulline or melatonin supplements, can be protective in both genetic and developmentally programmed hypertension. Furthermore, a significantly increased expression of gene Ephx2 (soluble epoxide hydrolase) was noted in both genetic and acquired animal models of hypertension. Since a suboptimal environment is often multifactorial, such common reprogramming pathways are a practical finding for translation to the clinic. This review provides an overview of potential clinical applications of reprogramming strategies to prevent programmed hypertension. We emphasize the kidney in the following areas: mechanistic insights from human studies and animal models to interpret programmed hypertension; identified risk factors of human programmed hypertension from mother-child cohorts; and the impact of reprogramming strategies on programmed hypertension from animal models. It is critical that the observed effects on developmental reprogramming in animal models are replicated in human studies.

PPARs Link Early Life Nutritional Insults to Later Programmed Hypertension and Metabolic Syndrome

Hypertension is an important component of metabolic syndrome. Adulthood hypertension and metabolic syndrome can be programmed in response to nutritional insults in early life. Peroxisome proliferator-activated receptors (PPARs) serve as a nutrient-sensing signaling linking nutritional programming to hypertension and metabolic syndrome. All three members of PPARs, PPARα, PPARβ/δ, and PPARγ, are expressed in the kidney and involved in blood pressure control. This review provides an overview of potential clinical applications of targeting on the PPARs in the kidney to prevent programmed hypertension and metabolic syndrome, with an emphasis on the following areas: mechanistic insights to interpret programmed hypertension; the link between the PPARs, nutritional insults, and programmed hypertension and metabolic syndrome; the impact of PPAR signaling pathway in a maternal high-fructose model; and current experimental studies on early intervention by PPAR modulators to prevent programmed hypertension and metabolic syndrome. Animal studies employing a reprogramming strategy via targeting PPARs to prevent hypertension have demonstrated interesting results. It is critical that the observed effects on developmental reprogramming in animal models are replicated in human studies, to halt the globally-growing epidemic of metabolic syndrome-related diseases.

Maternal Melatonin Therapy Rescues Prenatal Dexamethasone and Postnatal High-Fat Diet Induced Programmed Hypertension in Male Rat Offspring

Prenatal dexamethasone (DEX) exposure and high-fat (HF) intake are linked to hypertension. We examined whether maternal melatonin therapy prevents programmed hypertension synergistically induced by prenatal DEX plus postnatal HF in adult offspring. We also examined whether DEX and melatonin causes renal programming using next-generation RNA sequencing (NGS) technology. Pregnant Sprague-Dawley rats received intraperitoneal dexamethasone (0.1 mg/kg) or vehicle from gestational day 16 to 22. In the melatonin-treatment groups (M), rats received 0.01% melatonin in drinking water during their entire pregnancy and lactation. Male offspring were assigned to five groups: control, DEX, HF, DEX+HF, and DEX+HF+M. Male offspring in the HF group were fed a HF diet from weaning to 4 months of age. Prenatal DEX and postnatal HF diet synergistically induced programmed hypertension in adult offspring, which melatonin prevented. Maternal melatonin treatment modified over 3000 renal transcripts in the developing offspring kidney. Our NGS data indicate that PPAR signaling and fatty acid metabolism are two significantly regulated pathways. In addition, maternal melatonin therapy elicits longstanding alterations on renal programming, including regulation of the melatonin signaling pathway and upregulation of Agtr1b and Mas1 expression in the renin-angiotensin system (RAS), to protect male offspring against programmed hypertension. Postnatal HF aggravates prenatal DEX induced programmed hypertension in adult offspring, which melatonin prevented. The protective effects of melatonin on programmed hypertension is associated with regulation of the RAS and melatonin receptors. The long-term effects of maternal melatonin therapy on renal transcriptome require further clarification.

Prenatal dexamethasone-induced programmed hypertension and renal programming

AIMS

Antenatal glucocorticoids can induce long-term effects on offspring health, including hypertension. Programmed hypertension has been observed in a prenatal dexamethasone (DEX) exposure model. However, how renal programming responds to prenatal DEX at different stages of development and the impact of DEX on programmed hypertension remain unclear. Therefore, we utilized RNA next-generation sequencing (NGS) to analyze the renal transcriptome in the offspring to examine whether key genes and pathways are responsible for DEX-induced renal programming and hypertension.

MAIN METHODS

Pregnant rats received intraperitoneal dexamethasone from gestational day 16 to 22. Prenatal DEX-induced programmed hypertension was examined in male offspring at 16 weeks of age.

KEY FINDINGS

Prenatal DEX modified 431 renal transcripts from the nephrogenesis stage to adulthood in a constant manner. At the pre-hypertensive and established hypertension stages, we identified 11 and 13 differentially expressed genes related to blood pressure regulation, respectively. Among these genes, Npr3, Ptgs2, Agt, Edn3, Ephx2, Agtr1b, and Gucy1a3 are associated with endothelium-derived hyperpolarizing and contractile factors (EDHF and EDCF). Genes in the arachidonic acid metabolism pathway may potentially be key genes contributing to programmed hypertension. In addition, DEX induced soluble epoxide hydrolase expression (Ephx2 gene encoding protein).

SIGNIFICANCE

Prenatal DEX elicits an imbalance between EDHFs and EDCFs that might lead to renal programming and hypertension. The arachidonic acid metabolism pathway is a common pathway contributing to programmed hypertension. Our results highlight candidate genes and pathways involved in renal programming as targets for therapeutic approaches to prevent programmed hypertension in children exposed to antenatal corticosteroids.