Neonatal alcohol exposure differentially alters clock gene oscillations within the suprachiasmatic nucleus, cerebellum, and liver of adult rats

Circadian organization of clock factors, antioxidant defenses, and cognitive genes expression, is lost in the cerebellum of aged rats. Possible targets of therapeutic strategies for the treatment of age-related cerebellar disorders

Aging is a major risk factor for cognitive deficits, impaired locomotion, and gait disorders. Although oxidative stress and circadian disruption are involved in both normal aging and the pathogenesis of age-associated diseases, just a very few studies explore the consequences of aging on circadian rhythms in the cerebellum. Here, we investigated age-dependent changes in the circadian organization of the molecular clock, antioxidant defenses and synaptic plasticity-related factors, in the rat cerebellum, and discussed the impact of that altered temporal organization on the cognitive function of this brain area. Particularly, we examined the circadian patterns of Brain and muscle ARNT-like 1 (BMAL1) protein levels, Glutathione peroxidase 4 (GPx4) gene expression, GPx and Catalase (CAT) enzymes activity, reduced glutathione (GSH) levels, and the Brain-derived neurotrophic factor (Bdnf) and its Tyrosine kinase receptor B (TrkB) circadian expression. Endogenously-driven circadian rhythms of BMAL1, GPx4, CAT, GSH, and Bdnf/TrkB factors, were observed in the young rat cerebellum. The rhythms' acrophases show a circadian organization that might be crucial for the daily cerebellar-dependent cognitive functions. Notably, aging disrupted circadian rhythms and the temporal organization of BMAL1, antioxidant defenses, and cognitive Bdnf/TrkB gene expression. Increased oxidative stress and disruption of clock-controlled rhythms during aging, might precede and cause the loss of circadian organization in the aged cerebellum. We expect our results highlight circadian rhythms of the studied factors as new targets for the treatment of age-dependent cerebellar disorders.

Characteristics of sleep in children with heavy prenatal alcohol exposure

BACKGROUND

Sleep plays an important role in neurodevelopment. However, the effects of prenatal alcohol exposure on sleep quality have been understudied, despite reports of sleep disturbance in infants prenatally exposed to alcohol and elevated levels of sleep problems reported by caregivers of children with fetal alcohol spectrum disorders. The current study characterizes sleep in children with prenatal alcohol exposure using both objective (actigraphy) and subjective (questionnaires, sleep diaries) methods.

METHODS

Participants aged 6-10 years, with and without prenatal alcohol exposure, were included in the study (alcohol-exposed [AE]: n = 35; control [CON]: n = 39). Objective sleep was measured via 24-h actigraphy for 2 weeks. Parents completed sleep diaries and sleep questionnaires (Children's Sleep Habits Questionnaire, Pediatric Sleep Questionnaire). Multivariate analysis of variance was used to characterize the sleep profile (objective, subjective) and examine group differences.

RESULTS

There were no group differences on actigraphy metrics averaged across 2 weeks. However, the AE group showed significantly greater intraindividual variability on most actigraphy measures, particularly total sleep time, percent sleep, wake after sleep onset, and number of wake bouts. Parents reported significantly more sleep problems in the AE group than in the CON group, primarily driven by night wakings, parasomnias (e.g., sleepwalking), snoring, and daytime sleepiness. These effects were more severe in children >8.5 years of age.

CONCLUSIONS

Despite similar 2-week average sleep outcomes, children with prenatal alcohol exposure showed greater intraindividual sleep variability and parents reported more sleep problems related to sleep behavior and snoring. These difficulties with sleep may be related to other cognitive and behavioral outcomes. Importantly, sleep is a modifiable behavior, and interventions that focus on variability in sleep, particularly in sleep duration, can impact the quality of life in children with prenatal alcohol exposure and their families.

Developmental alcohol exposure is exhausting: Sleep and the enduring consequences of alcohol exposure during development

Prenatal alcohol exposure is the leading nongenetic cause of human intellectual impairment. The long-term impacts of prenatal alcohol exposure on health and well-being are diverse, including neuropathology leading to behavioral, cognitive, and emotional impairments. Additionally negative effects also occur on the physiological level, such as the endocrine, cardiovascular, and immune systems. Among these diverse impacts is sleep disruption. In this review, we describe how prenatal alcohol exposure affects sleep, and potential mechanisms of those effects. Furthermore, we outline the evidence that sleep disruption across the lifespan may be a mediator of some cognitive and behavioral impacts of developmental alcohol exposure, and thus may represent a promising target for treatment.

Homeostatic NREM sleep and salience network function in adult mice exposed to ethanol during development

Developmental exposure to ethanol is a leading cause of cognitive, emotional and behavioral problems, with fetal alcohol spectrum disorder (FASD) affecting more than 1:100 children. Recently, comorbid sleep deficits have been highlighted in these disorders, with sleep repair a potential therapeutic target. Animal models of FASD have shown non-REM (NREM) sleep fragmentation and slow-wave oscillation impairments that predict cognitive performance. Here we use a mouse model of perinatal ethanol exposure to explore whether reduced sleep pressure may contribute to impaired NREM sleep, and compare the function of a brain network reported to be impacted by insomnia-the Salience network-in developmental ethanol-exposed mice with sleep-deprived, saline controls. Mice were exposed to ethanol or saline on postnatal day 7 (P7) and allowed to mature to adulthood for testing. At P90, telemetered cortical recordings were made for assessment of NREM sleep in home cage before and after 4 h of sleep deprivation to assess basal NREM sleep and homeostatic NREM sleep response. To assess Salience network functional connectivity, mice were exposed to the 4 h sleep deprivation period or left alone, then immediately sacrificed for immunohistochemical analysis of c-Fos expression. The results show that developmental ethanol severely impairs both normal rebound NREM sleep and sleep deprivation induced increases in slow-wave activity, consistent with reduced sleep pressure. Furthermore, the Salience network connectome in rested, ethanol-exposed mice was most similar to that of sleep-deprived, saline control mice, suggesting a sleep deprivation-like state of Salience network function after developmental ethanol even without sleep deprivation.

Blockade of alcohol excessive and "relapse" drinking in male mice by pharmacological cryptochrome (CRY) activation

RATIONALE

Metabolic dysfunction, mood disorders, anxiety disorders, and substance abuse disorders are associated with disruptions in circadian rhythm and circadian clock gene machinery. While the effects of alcohol on several core components of the clock genes have been described in rodent models, pharmacological activation or inhibition of clock gene functions has not been studied on alcohol drinking behaviors.

OBJECTIVES

We investigated whether cryptochrome (CRY1/2) activator KL001 altered alcohol intake in mice in excessive and relapse-like alcohol drinking models.

METHODS

Mice, subjected to 3 weeks of chronic intermittent alcohol drinking (IAD) (two-bottle choice, 24-h access every other day) developed excessive alcohol intake and high preference. We evaluated the pharmacological effects of KL001 after either 1-day acute withdrawal from IAD or 1-week chronic withdrawal using the alcohol deprivation effect (ADE) model.

RESULTS

Single pretreatment with KL001 at 1-4 mg kg-1 reduced alcohol intake and preference after acute withdrawal in a dose-related manner. The effect of KL001 on reducing excessive alcohol consumption seems alcohol specific, as the compound does not alter sucrose (caloric reinforcer) or saccharin (noncaloric reinforcer) consumption in mice. Both single- and multiple-dosing regimens with an effective dose of KL001 (4 mg kg-1) prevented the ADE after chronic withdrawal, with no tolerance development after the multi-dosing regimen.

CONCLUSIONS

Pretreatment with KL001 (a CRY1/2 activator) reduces excessive and "relapse" alcohol drinking in mice. Our in vivo results with a CRY activator suggest a possible novel target for alcohol treatment intervention.

A Review of Sleep Disturbances among Infants and Children with Neurodevelopmental Disorders

Sleep problems are common among children with neurodevelopmental disorders (NDDs). We review sleep disturbance in three major NDDs: autism spectrum disorder, Down syndrome, and fetal alcohol spectrum disorder (FASD). We review associations with functional impairment, discuss how patterns of sleep disturbance inform understanding of etiology, and theorize about mechanisms of impairment. Sleep disturbance is a transdiagnostic feature of NDDs. Caregivers report high rates of sleep problems, including difficulty falling or staying asleep. Polysomnography data reveal differences in sleep architecture and increased rates of sleep disorders. Sleep disturbance is associated with functional impairment and stress among families. Further research is needed to elucidate mechanisms of impairment and develop more effective interventions. Despite significant sleep disturbance in FASD, limited research is available.

Rhythmic Release of Corticosterone Induces Circadian Clock Gene Expression in the Cerebellum

Neurons of the cerebellar cortex contain a circadian oscillator, with circadian expression of clock genes being controlled by the master clock of the suprachiasmatic nucleus (SCN). However, the signaling pathway connecting the SCN to the cerebellum is unknown. Glucocorticoids exhibit a prominent SCN-dependent circadian rhythm, and high levels of the glucocorticoid receptor have been reported in the cerebellar cortex; we therefore hypothesized that glucocorticoids may control the rhythmic expression of clock genes in the cerebellar cortex. We here applied a novel methodology by combining the electrolytic lesion of the SCN with implantation of a micropump programmed to release corticosterone in a circadian manner mimicking the endogenous hormone profile. By use of this approach, we were able to restore the corticosterone rhythm in SCN-lesioned male rats. Clock gene expression in the cerebellum was abolished in rats with a lesioned SCN, but exogenous corticosterone restored the daily rhythm in clock gene expression in the cerebellar cortex, as revealed by quantitative real-time PCR and radiochemical in situ hybridization for the detection of the core clock genes Per1, Per2, and Arntl. On the contrary, exogenous hormone did not restore circadian rhythms in body temperature and running activity. RNAscope in situ hybridization further revealed that the glucocorticoid receptor colocalizes with clock gene products in cells of the cerebellar cortex, suggesting that corticosterone exerts its actions by binding directly to receptors in neurons of the cerebellum. However, rhythmic clock gene expression in the cerebellum was also detectable in adrenalectomized rats, indicating that additional control mechanisms exist. These data show that the cerebellar circadian oscillator is influenced by SCN-dependent rhythmic release of corticosterone.

Sleep in Infants and Children with Prenatal Alcohol Exposure

Prenatal exposure to alcohol can result in a range of neurobehavioral impairments and physical abnormalities. The term "fetal alcohol spectrum disorders (FASD)" encompasses the outcomes of prenatal alcohol exposure (PAE), the most severe of which is fetal alcohol syndrome. These effects have lifelong consequences, placing a significant burden on affected individuals, caregivers, and communities. Caregivers of affected children often report that their child has sleep problems, and many symptoms of sleep deprivation overlap with the cognitive and behavioral deficits characteristic of FASD. Alcohol-exposed infants and children demonstrate poor sleep quality based on measures of electroencephalography, actigraphy, and questionnaires. These sleep studies indicate a common theme of disrupted sleep pattern, more frequent awakenings, and reduced total sleep time. However, relatively little is known about circadian rhythm disruption and the neurobehavioral correlates of sleep disturbance in individuals with PAE. Furthermore, there is limited information available to healthcare providers about identification and treatment of sleep disorders in patients with FASD. This review consolidates the findings from studies of infant and pediatric sleep in this population, providing an overview of typical sleep characteristics, neurobehavioral correlates of sleep disruption, and potential avenues for intervention in the context of PAE.

Circadian Clock Proteins and Melatonin Receptors in Neurons and Glia of the Sapajus apella Cerebellum

Oscillations of brain proteins in circadian rhythms are important for determining several cellular and physiological processes in anticipation of daily and seasonal environmental rhythms. In addition to the suprachiasmatic nucleus, the primary central oscillator, the cerebellum shows oscillations in gene and protein expression. The variety of local circuit rhythms that the cerebellar cortex contains influences functions such as motivational processes, regulation of feeding, food anticipation, language, and working memory. The molecular basis of the cerebellar oscillator has been demonstrated by "clock gene" expression within cells of the cerebellar layers. Genetic and epidemiological evidence suggests that disruption of circadian rhythms in humans can lead to many pathological conditions. Despite this importance, data about clock gene and protein expression in the cerebellum of diurnal (day-active) species, specifically primates, is currently poorly explored, mainly in regard to cellular identity, as well as the relationship with other molecules also involved in cerebellar functions. These studies could contribute to clarification of the possible mechanisms behind cerebellar rhythmicity. Considering that calcium binding proteins (CaBPs) play crucial roles in preserving and modulating cerebellar functions and that clock gene expression can be controlled by afferent projections or paracrine circadian signals such as the hormone melatonin, the present study aimed to describe cellular identities, distribution patterns and day/night expression changes in PER1, PER2, CaBPs, and MT₁ and MT₂ melatonin receptors in the cerebellar cortex of a diurnal primate using conventional fluorescence and peroxidase-antiperoxidase immunocytochemical techniques. PER1 and PER2 immunoreactive (IR) cells were observed in the Purkinje cells of the cerebellum, and MT₁ and MT₂ receptors were localized around Purkinje cells in the Pj layer in Bergmann cells. This identity was confirmed by the S100β-IR of these cells. The highest expression of PER seen in the daytime analysis coincided with the highest expression of melatonin receptors. CaBPs showed day/night morphological and density changes in the cerebellar cortex. The presence of the same temporal variations in the expression of PER in the Pj neurons and in MT₁ and MT₂ receptors in Bergmann cells indicates a possible relation between these cells during the rhythmic processing of the cerebellum, in addition to the CaBP temporal morphological and density changes.

Inhibition of p38 MAPK activity leads to cell type-specific effects on the molecular circadian clock and time-dependent reduction of glioma cell invasiveness

BACKGROUND

The circadian clock is the basis for biological time keeping in eukaryotic organisms. The clock mechanism relies on biochemical signaling pathways to detect environmental stimuli and to regulate the expression of clock-controlled genes throughout the body. MAPK signaling pathways function in both circadian input and output pathways in mammals depending on the tissue; however, little is known about the role of p38 MAPK, an established tumor suppressor, in the mammalian circadian system. Increased expression and activity of p38 MAPK is correlated with poor prognosis in cancer, including glioblastoma multiforme; however, the toxicity of p38 MAPK inhibitors limits their clinical use. Here, we test if timed application of the specific p38 MAPK inhibitor VX-745 reduces glioma cell invasive properties in vitro.

METHODS

The levels and rhythmic accumulation of active phosphorylated p38 MAPK in different cell lines were determined by western blots. Rhythmic luciferase activity from clock gene luciferase reporter cells lines was used to test the effect of p38 MAPK inhibition on clock properties as determined using the damped sine fit and Levenberg-Marquardt algorithm. Nonlinear regression and Akaike's information criteria were used to establish rhythmicity. Boyden chamber assays were used to measure glioma cell invasiveness following time-of-day-specific treatment with VX-745. Significant differences were established using t-tests.

RESULTS

We demonstrate the activity of p38 MAPK cycles under control of the clock in mouse fibroblast and SCN cell lines. The levels of phosphorylated p38 MAPK were significantly reduced in clock-deficient cells, indicating that the circadian clock plays an important role in activation of this pathway. Inhibition of p38 MAPK activity with VX-745 led to cell-type-specific period changes in the molecular clock. In addition, phosphorylated p38 MAPK levels were rhythmic in HA glial cells, and high and arrhythmic in invasive IM3 glioma cells. We show that inhibition of p38 MAPK activity in IM3 cells at the time of day when the levels are normally low in HA cells under control of the circadian clock, significantly reduced IM3 invasiveness.

CONCLUSIONS

Glioma treatment with p38 MAPK inhibitors may be more effective and less toxic if administered at the appropriate time of the day.

Understanding and managing sleep disruption in children with fetal alcohol spectrum disorder

Accumulating evidence has revealed high rates of sleep disruption among children with fetal alcohol spectrum disorder (FASD). Multiple animal and clinical studies have found a clear association between sleep problems and prenatal alcohol exposure, and recent research is beginning to characterize the types and extent of sleep disruption in FASD. Nevertheless, sleep disruption in children with FASD often goes unrecognized or is treated without referring to an evidence base. Children's disrupted sleep interferes with parental sleep and increases caregiver burden, which is of particular importance for families raising children with FASD, a group with very high levels of caregiving stress. The literature supporting an association between sleep problems and deficits in emotional, behavioral, and cognitive function in children is compelling, but needs further investigation in children with FASD. This paper will review the current state of knowledge on sleep in FASD and recommend a rational approach to sleep interventions for affected children and their families.

Deleting the Arntl clock gene in the granular layer of the mouse cerebellum: impact on the molecular circadian clockwork

The suprachiasmatic nucleus houses the central circadian clock and is characterized by the timely regulated expression of clock genes. However, neurons of the cerebellar cortex also contain a circadian oscillator with circadian expression of clock genes being controlled by the suprachiasmatic nucleus. It has been suggested that the cerebellar circadian oscillator is involved in food anticipation, but direct molecular evidence of the role of the circadian oscillator of the cerebellar cortex is currently unavailable. To investigate the hypothesis that the circadian oscillator of the cerebellum is involved in circadian physiology and food anticipation, we therefore by use of Cre-LoxP technology generated a conditional knockout mouse with the core clock gene Arntl deleted specifically in granule cells of the cerebellum, since expression of clock genes in the cerebellar cortex is mainly located in this cell type. We here report that deletion of Arntl heavily influences the molecular clock of the cerebellar cortex with significantly altered and arrhythmic expression of other central clock and clock-controlled genes. On the other hand, daily expression of clock genes in the suprachiasmatic nucleus was unaffected. Telemetric registrations in different light regimes did not detect significant differences in circadian rhythms of running activity and body temperature between Arntl conditional knockout mice and controls. Furthermore, food anticipatory behavior did not differ between genotypes. These data suggest that Arntl is an essential part of the cerebellar oscillator; however, the oscillator of the granular layer of the cerebellar cortex does not control traditional circadian parameters or food anticipation.

Chronic Alcohol Consumption in Rats Leads to Desynchrony in Diurnal Rhythms and Molecular Clocks

BACKGROUND

Circadian rhythms are essential for adapting to the environment. Chronic alcohol consumption often leads to sleep and circadian disruptions, which may impair the life quality of individuals with alcohol use disorders and contribute to the morbidity associated with alcoholism.

METHODS

We used a pair-feeding liquid diet alcohol exposure protocol (6 weeks duration) in PER1::LUC transgenic rats to examine the effects of chronic alcohol exposure on: (i) diurnal rhythms of core body temperature and locomotor activity, (ii) plasma corticosterone (CORT) concentrations, and (iii) rhythms of ex vivo Period1 (Per1) expression in the suprachiasmatic nucleus (SCN), pituitary, and adrenal glands. We followed multiple circadian outputs not only to examine individual components, but also to assess the relative phase relationships among rhythms.

RESULTS

We found that chronic alcohol consumption: (i) reduced 24-hour body temperature and locomotor activity counts in the dark period, (ii) advanced the acrophase of diurnal rhythms of body temperature and locomotor activity, (iii) abolished the phase difference between temperature and activity rhythms, (iv) blunted and advanced the diurnal CORT rhythm, and (v) advanced Per1 expression in the adrenal and pituitary glands but not in the SCN. We found that chronic alcohol altered the phase relationships among diurnal rhythms and between the central (SCN) and peripheral (adrenal and pituitary) molecular clocks.

CONCLUSIONS

Our findings suggest that desynchrony among internal rhythms is an important and overlooked aspect of alcohol-induced circadian disruptions. The misalignment of phases among rhythms may compromise normal physiological functions and put individuals with chronic alcohol use at greater risk for developing other physical and mental health issues. How this desynchrony occurs and the extent to which it participates in alcohol-related pathologies requires further investigation.

Circadian rhythms of clock gene expression in the cerebellum of serotonin-deficient Pet-1 knockout mice

Serotonin plays an important role in the central regulation of circadian clock function. Serotonin levels are generally higher in the brain during periods of high activity, and these periods are in turn heavily regulated by the circadian clock located in the suprachiasmatic nucleus. However, the role of serotonin as a regulator of circadian rhythms elsewhere in the brain has not been extensively examined. In this study, we examined circadian rhythms of clock gene expression in the cerebellum in mice lacking the Pet-1 transcription factor, which results in a developed brain that is deficient in serotonin neurons. If serotonin helps to synchronize rhythms in brain regions other than the suprachiasmatic nucleus, we would expect to see differences in clock gene expression in these serotonin deficient mice. We found minor differences in the expression of Per1 and Per2 in the knockout mice as compared to wild type, but these differences were small and of questionable functional importance. We also measured the response of cerebellar clocks to injections of the serotonin agonist 8-OH-DPAT during the early part of the night. No effect on clock genes was observed, though the immediate-early gene Fos showed increased expression in wild type mice but not the knockouts. These results suggest that serotonin is not an important mediator of circadian rhythms in the cerebellum in a way that parallels its regulation of the circadian clock in the suprachiasmatic nucleus.

The Molecular Circadian Clock and Alcohol-Induced Liver Injury

Emerging evidence from both experimental animal studies and clinical human investigations demonstrates strong connections among circadian processes, alcohol use, and alcohol-induced tissue injury. Components of the circadian clock have been shown to influence the pathophysiological effects of alcohol. Conversely, alcohol may alter the expression of circadian clock genes and the rhythmic behavioral and metabolic processes they regulate. Therefore, we propose that alcohol-mediated disruption in circadian rhythms likely underpins many adverse health effects of alcohol that cut across multiple organ systems. In this review, we provide an overview of the circadian clock mechanism and showcase results from new studies in the alcohol field implicating the circadian clock as a key target of alcohol action and toxicity in the liver. We discuss various molecular events through which alcohol may work to negatively impact circadian clock-mediated processes in the liver, and contribute to tissue pathology. Illuminating the mechanistic connections between the circadian clock and alcohol will be critical to the development of new preventative and pharmacological treatments for alcohol use disorders and alcohol-mediated organ diseases.

Activity and social behavior in a complex environment in rats neonatally exposed to alcohol

Environmental complexity (EC) is a powerful, stimulating paradigm that engages animals through a variety of sensory and motor pathways. Exposure to EC (30 days) following 12 days of wheel running preserves hippocampal neuroplasticity in male rats neonatally exposed to alcohol during the third-trimester equivalent (binge-like exposure on postnatal days [PD] 4-9). The current experiment investigates the importance of various components of EC (physical activity, exploration, social interaction, novelty) and examines whether neonatal alcohol exposure affects how male rats interact with their environment and other male rats. Male pups were assigned to 1 of 3 neonatal conditions from PD 4-9: suckle control (SC), sham-intubated (SI), or alcohol-exposed (AE, 5.25 g/kg/day). From PD 30-42 animals were housed with 24-h access to a voluntary running wheel. The animals were then placed in EC from PD 42-72 (9 animals/cage, counterbalanced by neonatal condition). During EC, the animals were filmed for five 30-min sessions (PD 42, 48, 56, 64, 68). For the first experiment, the videos were coded for distance traveled in the cage, overall locomotor activity, time spent near other animals, and interaction with toys. For the second experiment, the videos were analyzed for wrestling, mounting, boxing, grooming, sniffing, and crawling over/under. AE animals were found to be less active and exploratory and engaged in fewer mounting behaviors compared to control animals. Results suggest that after exposure to wheel running, AE animals still have deficits in activity and social behaviors while housed in EC compared to control animals with the same experience.

Circadian rhythms and addiction: mechanistic insights and future directions

Circadian rhythms are prominent in many physiological and behavioral functions. Circadian disruptions either by environmental or molecular perturbation can have profound health consequences, including the development and progression of addiction. Both animal and humans studies indicate extensive bidirectional relationships between the circadian system and drugs of abuse. Addicted individuals display disrupted rhythms, and chronic disruption or particular chronotypes may increase the risk for substance abuse and relapse. Moreover, polymorphisms in circadian genes and an evening chronotype have been linked to mood and addiction disorders, and recent efforts suggest an association with the function of reward neurocircuitry. Animal studies are beginning to determine how altered circadian gene function results in drug-induced neuroplasticity and behaviors. Many studies suggest a critical role for circadian rhythms in reward-related pathways in the brain and indicate that drugs of abuse directly affect the central circadian pacemaker. In this review, we highlight key findings demonstrating the importance of circadian rhythms in addiction and how future studies will reveal important mechanistic insights into the involvement of circadian rhythms in drug addiction.

Circadian rhythms in liver physiology and liver diseases

In mammals, circadian rhythms function to coordinate a diverse panel of physiological processes with environmental conditions such as food and light. As the driving force for circadian rhythmicity, the molecular clock is a self-sustained transcription-translational feedback loop system consisting of transcription factors, epigenetic modulators, kinases/phosphatases, and ubiquitin E3 ligases. The molecular clock exists not only in the suprachiasmatic nuclei of the hypothalamus but also in the peripheral tissues to regulate cellular and physiological function in a tissue-specific manner. The circadian clock system in the liver plays important roles in regulating metabolism and energy homeostasis. Clock gene mutant animals display impaired glucose and lipid metabolism and are susceptible to diet-induced obesity and metabolic dysfunction, providing strong evidence for the connection between the circadian clock and metabolic homeostasis. Circadian-controlled hepatic metabolism is partially achieved by controlling the expression and/or activity of key metabolic enzymes, transcription factors, signaling molecules, and transporters. Reciprocally, intracellular metabolites modulate the molecular clock activity in response to the energy status. Although still at the early stage, circadian clock dysfunction has been implicated in common chronic liver diseases. Circadian dysregulation of lipid metabolism, detoxification, reactive oxygen species (ROS) production, and cell-cycle control might contribute to the onset and progression of liver steatosis, fibrosis, and even carcinogenesis. In summary, these findings call for a comprehensive study of the function and mechanisms of hepatic circadian clock to gain better understanding of liver physiology and diseases.

Chronic ethanol consumption disrupts the core molecular clock and diurnal rhythms of metabolic genes in the liver without affecting the suprachiasmatic nucleus

Chronic ethanol consumption disrupts several metabolic pathways including β-oxidation and lipid biosynthesis, facilitating the development of alcoholic fatty liver disease. Many of these same metabolic pathways are directly regulated by cell autonomous circadian clocks, and recent studies suggest that disruption of daily rhythms in metabolism contributes to multiple common cardiometabolic diseases (including non-alcoholic fatty liver disease). However, it is not known whether ethanol disrupts the core molecular clock in the liver, nor whether this, in turn, alters rhythms in lipid metabolism. Herein, we tested the hypothesis that chronic ethanol consumption disrupts the molecular circadian clock in the liver and potentially changes the diurnal expression patterns of lipid metabolism genes. Consistent with previous studies, male C57BL/6J mice fed an ethanol-containing diet exhibited higher levels of liver triglycerides compared to control mice, indicating hepatic steatosis. Further, the diurnal oscillations of core clock genes (Bmal1, Clock, Cry1, Cry2, Per1, and Per2) and clock-controlled genes (Dbp, Hlf, Nocturnin, Npas2, Rev-erbα, and Tef) were altered in livers from ethanol-fed mice. In contrast, ethanol had only minor effects on the expression of core clock genes in the suprachiasmatic nucleus (SCN). These results were confirmed in Per2^Luciferase knock-in mice, in which ethanol induced a phase advance in PER2::LUC bioluminescence oscillations in liver, but not SCN. Further, there was greater variability in the phase of PER2::LUC oscillations in livers from ethanol-fed mice. Ethanol consumption also affected the diurnal oscillations of metabolic genes, including Adh1, Cpt1a, Cyp2e1, Pck1, Pdk4, Ppargc1a, Ppargc1b and Srebp1c, in the livers of C57BL/6J mice. In summary, chronic ethanol consumption alters the function of the circadian clock in liver. Importantly, these results suggest that chronic ethanol consumption, at levels sufficient to cause steatosis, disrupts the core hepatic clock as well as the diurnal rhythms of key lipid metabolism genes.

Role of miR-142-3p in the post-transcriptional regulation of the clock gene Bmal1 in the mouse SCN

MicroRNAs (miRNAs) are small non-coding RNAs that function as post-transcriptional modulators by regulating stability or translation of target mRNAs. Recent studies have implicated miRNAs in the regulation of mammalian circadian rhythms. To explore the role of miRNAs in the post-transcriptional modulation of core clock genes in the master circadian pacemaker, we examined miR-142-3p for evidence of circadian expression in the suprachiasmatic nuclei (SCN), regulation of its putative clock gene target Bmal1 via specific binding sites in the 3' UTR and overexpression-induced changes in the circadian rhythm of BMAL1 protein levels in SCN cells. In mice exposed to constant darkness (DD), miR-142-3p levels in the SCN were characterized by circadian rhythmicity with peak expression during early subjective day at CT 3. Mutagenesis studies indicate that two independent miRNA recognition elements located at nucleotides 1-7 and 335-357 contribute equally to miR-142-3p-induced repression of luciferase-reported Bmal1 3' UTR activity. Importantly, overexpression of miR-142-3p in immortalized SCN cells abolished circadian variation in endogenous BMAL1 protein levels in vitro. Collectively, our results suggest that miR-142-3p may play a role in the post-transcriptional modulation of Bmal1 and its oscillatory regulation in molecular feedback loops mediating SCN circadian function.

Circadian clock period inversely correlates with illness severity in cells from patients with alcohol use disorders

BACKGROUND

Clinical and genetic studies suggest circadian clock genes may contribute to biological mechanisms underlying alcohol use disorders (AUD). In particular, the Per2 gene regulates alcohol consumption in mutant animals, and in humans with AUD, the 10870 variant in PER2 has been associated with alcohol consumption. However, with respect to function, the molecular clock remains largely uncharacterized in AUD patients.

METHODS

In skin fibroblast cultures from well-characterized human AUD patients (n = 19) and controls (n = 13), we used a bioluminescent reporter gene (Per2::luc) to measure circadian rhythms in gene expression at high sampling density for 5 days. Cells were genotyped for the PER2 10870 variant. The rhythm parameters period and amplitude were then analyzed using a case-control design and by genetic and clinical characteristics of the AUD subjects.

RESULTS

There were no differences between AUD cases and controls in rhythm parameters. However, period was inversely correlated with illness severity (defined as the number of alcohol dependence criteria met). The PER2 variant 10870 was not associated with differences in rhythm parameters.

CONCLUSIONS

Our data suggest that differences in the cellular circadian clock are not pronounced in fibroblasts from AUD cases and controls. However, we found evidence that the circadian clock may be associated with an altered trajectory of AUD, possibly related to illness severity. Future work will be required to determine the mechanistic basis of this association.

Effects of resveratrol on changes induced by high-fat feeding on clock genes in rats

In mammals, the main component of the circadian system is the suprachiasmatic nucleus in the hypothalamus. However, circadian clocks are also present in most peripheral tissues, such as adipose tissue. The aim of the present study was to analyse the potential effects of resveratrol on changes induced by high-fat feeding in the expression of clock genes and clock-controlled genes in the white adipose tissue from rats. For this purpose, rats were divided into three groups: a control group, fed a standard diet, and two other groups, either fed a high-fat diet supplemented with resveratrol (RSV) or no resveratrol (HF). The expression of clock genes and clock-controlled genes was analysed by RT-PCR. Protein expression and fatty acid synthase (FAS) activity were also analysed. When comparing the controls, the RSV group showed similar patterns of response to the HF group, except for reverse erythroblastosis virus α (Rev-Erbα), which was down-regulated. The expression of this gene reached the same levels as in control rats. The response pattern of protein expression for Rev-Erbα was similar to that found for gene expression. High-fat feeding up-regulated all adipogenic genes and resveratrol did not modify them. In the HF group, the activity of FAS tended to increase, while resveratrol decreased. In conclusion, resveratrol reverses the change induced by high-fat feeding in the expression of Rev-Erbα in adipose tissue, which means that clock machinery is a target for this polyphenol. This change seems to be related to reduced lipogenesis, which might be involved in the body fat-lowering effect of this molecule.

Circadian disruption: potential implications in inflammatory and metabolic diseases associated with alcohol

Circadian rhythms are a prominent and critical feature of cells, tissues, organs, and behavior that help an organism function most efficiently and anticipate things such as food availability. Therefore, it is not surprising that disrupted circadian rhythmicity, a prominent feature of modern-day society, promotes the development and/or progression of a wide variety of diseases, including inflammatory, metabolic, and alcohol-associated disorders. This article will discuss the influence of interplay between alcohol consumption and circadian rhythmicity and how circadian rhythm disruption affects immune function and metabolism as well as potential epigenetic mechanisms that may be contributing to this phenomenon.

Alcohol metabolism and epigenetics changes

Metabolites, including those generated during ethanol metabolism, can impact disease states by binding to transcription factors and/or modifying chromatin structure, thereby altering gene expression patterns. For example, the activities of enzymes involved in epigenetic modifications such as DNA and histone methylation and histone acetylation, are influenced by the levels of metabolites such as nicotinamide adenine dinucleotide (NAD), adenosine triphosphate (ATP), and S-adenosylmethionine (SAM). Chronic alcohol consumption leads to significant reductions in SAM levels, thereby contributing to DNA hypomethylation. Similarly, ethanol metabolism alters the ratio of NAD+ to reduced NAD (NADH) and promotes the formation of reactive oxygen species and acetate, all of which impact epigenetic regulatory mechanisms. In addition to altered carbohydrate metabolism, induction of cell death, and changes in mitochondrial permeability transition, these metabolism-related changes can lead to modulation of epigenetic regulation of gene expression. Understanding the nature of these epigenetic changes will help researchers design novel medications to treat or at least ameliorate alcohol-induced organ damage.

Larval ethanol exposure alters free-running circadian rhythm and per Locus transcription in adult D. melanogaster period mutants

Alcohol consumption causes disruptions in a variety of daily rhythms, including the circadian free-running rhythm. A previous study conducted in our laboratories has shown that larval ethanol exposure alters the free-running period in adult Canton-S Drosophila melanogaster. Few studies, however, have explored the effect of alcohol exposure on organisms exhibiting circadian periods radically different than (normal) 24-h. We reared Canton-S, period long, and period short Drosophila melanogaster larvae on 10%-ethanol supplemented food, and assessed their adult free-running locomotor activity and period transcript at ZT 12. We demonstrate that in Canton-S larval ethanol exposure shortens the adult free-running locomotor activity but does not significantly alter period mRNA levels at ZT 12. Period long mutants exposed to larval ethanol had significantly shortened adult free-running locomotor activity rhythms and decreased period mRNA levels, while period short mutants lengthened their free-running rhythm and showed increased period mRNA levels at ZT 12 after being exposed to larval ethanol. These results indicate that the effects of ethanol on the circadian clock might depend upon the baseline circadian period of the organism or that period mutant gene expression is sensitive to developmental ethanol treatment.

Circadian oscillations of molecular clock components in the cerebellar cortex of the rat

The central circadian clock of the mammalian brain resides in the suprachiasmatic nucleus (SCN) of the hypothalamus. At the molecular level, the circadian clockwork of the SCN constitutes a self-sustained autoregulatory feedback mechanism reflected by the rhythmic expression of clock genes. However, recent studies have shown the presence of extrahypothalamic oscillators in other areas of the brain including the cerebellum. In the present study, the authors unravel the cerebellar molecular clock by analyzing clock gene expression in the cerebellum of the rat by use of radiochemical in situ hybridization and quantitative real-time polymerase chain reaction. The authors here show that all core clock genes, i.e., Per1, Per2, Per3, Cry1, Cry2, Clock, Arntl, and Nr1d1, as well as the clock-controlled gene Dbp, are expressed in the granular and Purkinje cell layers of the cerebellar cortex. Among these genes, Per1, Per2, Per3, Cry1, Arntl, Nr1d1, and Dbp were found to exhibit circadian rhythms in a sequential temporal manner similar to that of the SCN, but with several hours of delay. The results of lesion studies indicate that the molecular oscillatory profiles of Per1, Per2, and Cry1 in the cerebellum are controlled, though possibly indirectly, by the central clock of the SCN. These data support the presence of a circadian oscillator in the cortex of the rat cerebellum.

Integration of the circadian and stress systems: influence of neuropeptides and implications for alcohol consumption

Disruptions in circadian rhythm and stress reactivity are associated with risks of developing neuropsychiatric disorders. The circadian system is organised in a hierarchical manner, whereby the master clock is located at the suprachiasmatic nucleus, a highly conserved brain region that coordinates the oscillations of peripheral clocks. Exposure to psychological stress leads to activation of the hypothalamic-pituitary-adrenal axis. There is growing evidence supporting the interactions between the circadian and stress systems. Anatomically, the circadian and stress signals converge at the paraventricular nucleus (PVN) in the hypothalamus. Genes that are involved in the operation of the circadian and stress systems, including Clock, Period and CRH are expressed in the PVN. In addition, several neuropeptides, including arginin-vasopressin, vasoactive intestinal polypeptide, pituitary adenylate cyclase-activating polypeptide and the neurotransmitter gamma-aminobutyric acid, are present in the PVN. In this review, we will discuss the interaction of circadian genes and stress-response genes at the molecular, neurotransmission and behavioural levels. We will place particular emphasis on the role of neuropeptides in mediating this interaction.

Sleep problems in children with fetal alcohol spectrum disorders

STUDY OBJECTIVES

Sleep problems in children with fetal alcohol spectrum disorders (FASD) are reportedly common but not well characterized. Objectives were to: (1) assess sleep concerns in children with FASD using a caregiver-report survey, the Children's Sleep Habits Questionnaire (CSHQ); (2) compare CSHQ results with those of previously reported community sample; and (3) describe pilot polysomnography findings in children with FASD.

METHODS

Children with FASD were recruited from a behavioral intervention study, and participating caregivers completed the CSHQ. CSHQ results were compared with the original data from a previously published community sample of similar age. Participants with FASD and elevated CSHQ scores were offered overnight polysomnography.

RESULTS

Thirty-three children with FASD (4.1-12.1 years) were enrolled; 85% of children with FASD scored above the clinical cutoff Total Score of 41, reflecting marked sleep disturbance. Elevated subdomain scores occurred primarily in areas concerning for pediatric insomnia. Those with comorbid ADHD had elevated CSHQ on additional subdomains with no difference in Total Scores. Compared with the community sample, children with FASD had higher Total Scores on the CSHQ (52 vs. 39, p < 0.001). Polysomnography, completed in 5 subjects, revealed mild sleep disordered breathing and fragmented sleep with elevated non-respiratory arousal indices.

CONCLUSIONS

Clinically significant sleep problems are present in children with FASD on both subjective and objective measures. Further investigation is needed to better describe these sleep disturbances and their impact on overall health and daytime neurobehavioral problems in this clinical population.

Larval ethanol exposure alters adult circadian free-running locomotor activity rhythm in Drosophila melanogaster

Alcohol consumption causes disruptions in a variety of daily rhythms, including the sleep-wake cycle. Few studies have explored the effect of alcohol exposure only during developmental stages preceding maturation of the adult circadian clock, and none have examined the effects of alcohol on clock function in Drosophila. This study investigates developmental and behavioral correlates between larval ethanol exposure and the adult circadian clock in Drosophila melanogaster, a well-established model for studying circadian rhythms and effects of ethanol exposure. We reared Drosophila larvae on 0%, 10%, or 20% ethanol-supplemented food and assessed effects upon eclosion and the free-running period of the circadian rhythm of locomotor activity. We observed a dose-dependent effect of ethanol on period, with higher doses resulting in shorter periods. We also identified the third larval instar stage as a critical time for the developmental effects of 10% ethanol on circadian period. These results demonstrate that developmental ethanol exposure causes sustainable shortening of the adult free-running period in Drosophila melanogaster, even after adult exposure to ethanol is terminated, and suggests that the third instar is a sensitive time for this effect.

Circadian genes, the stress axis, and alcoholism

The body's internal system to control the daily rhythm of the body's functions (i.e., the circadian system), the body's stress response, and the body's neurobiology are highly interconnected. Thus, the rhythm of the circadian system impacts alcohol use patterns; at the same time, alcohol drinking also can alter circadian functions. The sensitivity of the circadian system to alcohol may result from alcohol's effects on the expression of several of the clock genes that regulate circadian function. The stress response system involves the hypothalamus and pituitary gland in the brain and the adrenal glands, as well as the hormones they secrete, including corticotrophin-releasing hormone, adrenocorticotrophic hormone, and glucocorticoids. It is controlled by brain-signaling molecules, including endogenous opioids such as β-endorphin. Alcohol consumption influences the activity of this system and vice versa. Finally, interactions exist between the circadian system, the hypothalamic-pituitary-adrenal axis, and alcohol consumption. Thus, it seems that certain clock genes may control functions of the stress response system and that these interactions are affected by alcohol.

Ethanol consumption and pineal melatonin daily profile in rats

It is well known that melatonin participates in the regulation of many important physiological functions such as sleep-wakefulness cycle, motor coordination and neural plasticity, and cognition. However, as there are contradictory results regarding the melatonin production diurnal profile under alcohol consumption, the aim of this paper was to study the phenomenology and mechanisms of the putative modifications on the daily profile of melatonin production in rats submitted to chronic alcohol intake. The present results show that rats receiving 10% ethanol in drinking water for 35 days display an altered daily profile of melatonin production, with a phase delay and a reduction in the nocturnal peak. This can be partially explained by a loss of the daily rhythm and the 25% reduction in tryptophan hydroxylase activity and, mainly, by a phase delay in arylalkylamine N-acetyltransferase gene expression and a 70% reduction in its peak activity. Upstream in the melatonin synthesis pathway, the results showed that noradrenergic signaling is impaired as well, with a decrease in β1 and α1 adrenergic receptors' mRNA contents and in vitro sustained loss of noradrenergic-stimulated melatonin production by glands from alcohol-treated rats. Together, these results confirm the alterations in the daily melatonin profile of alcoholic rats and suggest the possible mechanisms for the observed melatonin synthesis modification.

Effects of ethanol and NAP on cerebellar expression of the neural cell adhesion molecule L1

The neural cell adhesion molecule L1 is critical for brain development and plays a role in learning and memory in the adult. Ethanol inhibits L1-mediated cell adhesion and neurite outgrowth in cerebellar granule neurons (CGNs), and these actions might underlie the cerebellar dysmorphology of fetal alcohol spectrum disorders. The peptide NAP potently blocks ethanol inhibition of L1 adhesion and prevents ethanol teratogenesis. We used quantitative RT-PCR and Western blotting of extracts of cerebellar slices, CGNs, and astrocytes from postnatal day 7 (PD7) rats to investigate whether ethanol and NAP act in part by regulating the expression of L1. Treatment of cerebellar slices with 20 mM ethanol, 10⁻¹² M NAP, or both for 4 hours, 24 hours, and 10 days did not significantly affect L1 mRNA and protein levels. Similar treatment for 4 or 24 hours did not regulate L1 expression in primary cultures of CGNs and astrocytes, the predominant cerebellar cell types. Because ethanol also damages the adult cerebellum, we studied the effects of chronic ethanol exposure in adult rats. One year of binge drinking did not alter L1 gene and protein expression in extracts from whole cerebellum. Thus, ethanol does not alter L1 expression in the developing or adult cerebellum; more likely, ethanol disrupts L1 function by modifying its conformation and signaling. Likewise, NAP antagonizes the actions of ethanol without altering L1 expression.

Expression and rhythmic modulation of circulating microRNAs targeting the clock gene Bmal1 in mice

MicroRNAs (miRNAs) interact with 3' untranslated region (UTR) elements of target genes to regulate mRNA stability or translation and thus play a role in regulating many different biological processes, including circadian rhythms. However, specific miRNAs mediating the regulation of essential clock genes remain largely unknown. Because vesicles containing membrane-bound miRNAs are present in the circulatory system, we examined miRNAs predicted to target the clock gene, Bmal1, for evidence of rhythmic fluctuations in circulating levels and modulatory effects on the 3' UTR activity of Bmal1. A number of miRNAs with Bmal1 as a predicted target were expressed in the serum of mice exposed to LD 12:12 and of these miRNAs, miR-152 and miR-494 but not miR-142-3p were marked by diurnal oscillations with bimodal peaks in expression occurring near the middle of the day and 8 or 12 hr later during the night. Co-transfection of pre-miR over-expression constructs for miR-494 and miR-142-3p in HEK293 cells had significant effects in repressing luciferase-reported Bmal1 3' UTR activity by as much as 60%, suggesting that these miRNAs may function as post-transcriptional modulators of Bmal1. In conjunction with previous studies implicating miRNAs as extracellular regulatory signals, our results suggest that circulating miRNAs may play a role in the regulation of the molecular clockworks in peripheral circadian oscillators.

The clock gene Period3 in the nocturnal flatfish Solea senegalensis: Molecular cloning, tissue expression and daily rhythms in central areas

Clock genes are responsible for generating and sustaining most rhythmic daily functions in vertebrates. Their expression is endogenously driven, although they are entrained by external cues such as light, temperature and nutrient availability. In the present study, a full-length coding region of Solea senegalensis clock gene Period3 (Per3) has been isolated from sole brain as a first step in understanding the molecular basis underlying circadian rhythms in this nocturnal species. The complete cDNA is 4141 base pairs (bp) in length, including an ORF of 3804bp, a 5'UTR of 247bp and a 3'UTR of 90bp. It encodes a putative PERIOD3 protein (PER3) of 1267 amino acids which shares the main functional domains conserved between transcription factors regulating the circadian clock pathway. Sole PER3 displays high identity with PER3 proteins from teleost species (61-77%) and lower identity (39-46%) with other vertebrate PER3 sequences. This gene is expressed in all examined tissues, being mRNA expression particularly evident in retina, cerebellum, diencephalon, optic tectum, liver and ovary. Per3 exhibits a significant daily oscillation in retina and optic tectum but not in diencephalon and cerebellum. Our results suggest an important role of Per3 in the circadian clockwork machinery of visually-related areas of sole.

Period 2 gene deletion abolishes beta-endorphin neuronal response to ethanol

BACKGROUND

Ethanol exposure during early life has been shown to permanently alter the circadian expression of clock regulatory genes and the beta-endorphin precursor proopiomelanocortin (POMC) gene in the hypothalamus. Ethanol also alters the stress- and immune-regulatory functions of beta-endorphin neurons in laboratory rodents. Our aim was to determine whether the circadian clock regulatory Per2 gene modulates the action of ethanol on beta-endorphin neurons in mice.

METHODS

Per2 mutant (mPer2(Brdml)) and wild type (C57BL/6J) mice were used to determine the effect of Per2 mutation on ethanol-regulated beta-endorphin neuronal activity during neonatal period using an in vitro mediobasal hypothalamic (MBH) cell culture model and an in vivo milk formula feeding animal model. The beta-endorphin neuronal activity following acute and chronic ethanol treatments was evaluated by measuring the peptide released from cultured cells or peptide levels in the MBH tissues, using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Per2 mutant mice showed a higher basal level of beta-endorphin release from cultured MBH cells and a moderate increase in the peptide content in the MBH in comparison with control mice. However, unlike wild type mice, Per2 mutant mice showed no stimulatory or inhibitory beta-endorphin-secretory responses to acute and chronic ethanol challenges in vitro. Furthermore, Per2 mutant mice, but not wild type mice, failed to show the stimulatory and inhibitory responses of MBH beta-endorphin levels to acute and chronic ethanol challenges in vivo.

CONCLUSIONS

These results suggest for the first time that the Per2 gene may be critically involved in regulating beta-endorphin neuronal function. Furthermore, the data revealed an involvement of the Per2 gene in regulating beta-endorphin neuronal responses to ethanol.

The cerebellum harbors a circadian oscillator involved in food anticipation

The cerebellum participates in motor coordination as well as in numerous cerebral processes, including temporal discrimination. Animals can predict daily timing of food availability, as manifested by food-anticipatory activity under restricted feeding. By studying ex vivo clock gene expression by in situ hybridization and recording in vitro Per1-luciferase bioluminescence, we report that the cerebellum contains a circadian oscillator sensitive to feeding cues (i.e., whose clock gene oscillations are shifted in response to restricted feeding). Food-anticipatory activity was markedly reduced in mice injected intracerebroventricularly with an immunotoxin that depletes Purkinje cells (i.e., OX7-saporin). Mice bearing the hotfoot mutation (i.e., Grid2(ho/ho)) have impaired cerebellar circuitry and mild ataxic phenotype. Grid2(ho/ho) mice fed ad libitum showed regular behavioral rhythms and day-night variations of clock gene expression in the hypothalamus and cerebellum. When challenged with restricted feeding, however, Grid2(ho/ho) mice did not show any food-anticipatory rhythms, nor timed feeding-induced changes in cerebellar clock gene expression. In hypothalamic arcuate and dorsomedial nuclei, however, shifts in Per1 expression in response to restricted feeding were similar in cerebellar mutant and wild-type mice. Furthermore, plasma corticosterone and metabolites before mealtime did not differ between cerebellar mutant and wild-type mice. Together, these data define a role for the cerebellum in the circadian timing network and indicate that the cerebellar oscillator is required for anticipation of mealtime.

Omic analyses unravels global molecular changes in the brain and liver of a rat model for chronic Sake (Japanese alcoholic beverage) intake

The effects of chronic administration of Sake (Japanese alcoholic beverage, Nihonshu) on brain and liver of female F334 (Fisher) rats were surveyed via global omic analyses using DNA microarray, 2-DE, and proton nuclear magnetic resonance. Rats weaned at 4 wk of age were given free access to Sake (15% alcohol), instead of water. At 13 months of age, and 24 h after withdrawal of Sake supply, rats were sacrificed, and the whole brain and liver tissues dissected for analyses. In general, molecular changes in brain were found to be less than those in liver. Transcriptomics data revealed 36 and 9, and 80 and 62 up- and down-regulated genes, in the brain and liver, respectively, with binding and catalytic activity gene categories the most prominently changed. Results suggested Sake-induced fragility of brain and liver toxicity/damage, though no significant abnormalities in growth were seen. At protein level, a striking decrease was found in the expression of NADH dehydrogenase (ubiquinone) Fe-S protein 1 in brain, suggesting attenuation of mitochondrial metabolism. In liver, results again suggested an attenuation of mitochondrial function and, in addition, glycoproteins with unknown function were induced at protein and gene levels, suggesting possible changes in glycoprotein binding in that organ. Metabolomic analysis of brain revealed significant increases in valine, arginine/ornithine, alanine, glutamine, and choline with decreases in isoleucine, N-acetyl aspartate, taurine, glutamate, and gamma aminobutyric acid. Our results provide a detailed inventory of molecular components of both brain and liver after Sake intake, and may help to better understand effects of chronic Sake drinking.

Effects of neonatal alcohol exposure on vasoactive intestinal polypeptide neurons in the rat suprachiasmatic nucleus

Neonatal alcohol exposure produces long-term changes in the suprachiasmatic nucleus (SCN) that are presumably responsible for disturbances in the light-dark regulation of circadian behavior in adult rats, including the pattern of photoentrainment, rate of re-entrainment to shifted light-dark cycles, and phase-shifting responses to light. Because SCN neurons containing vasoactive intestinal polypeptide (VIP) receive direct photic input via the retinohypothalamic tract and thus play an important role in the circadian regulation of the SCN clock mechanism by light, the present study examined the long-term effects of neonatal alcohol exposure on VIP neuronal populations within the SCN of adult rats. Male Sprague-Dawley rat pups were exposed to alcohol (EtOH; 3.0, 4.5, or 6.0 g/kg/day) or isocaloric milk formula (gastrostomy control; GC) on postnatal days 4-9 using artificial-rearing methods. At 2-3 months of age, animals from the suckle control (SC), GC, and EtOH groups were exposed to constant darkness (DD) and SCN tissue was harvested for subsequent analysis of either VIP mRNA expression by quantitative polymerase chain reaction (PCR) and in situ hybridization or of VIP-immunoreactive (ir) neurons using stereological methods. Neonatal alcohol exposure had no impact on VIP mRNA expression but dramatically altered immunostaining of neurons containing this peptide within the SCN of adult rats. The relative abundance of VIP mRNA and anatomical distribution of neurons expressing this transcript were similar among all control- and EtOH-treated groups. However, the total number and density of VIP-ir neurons within the SCN were significantly decreased by about 35% in rats exposed to alcohol at a dose of 6.0 g/kg/day relative to that observed in both control groups. These results demonstrate that VIP neuronal populations in the SCN are vulnerable to EtOH-induced insult during brain development. The observed alterations in SCN neurons containing VIP may have an impact upon clock responses to light input and thus contribute to the long-term effects of neonatal alcohol exposure on the photic regulation of circadian behavior.