Health risks associated with genetic alterations in internal clock system by external factors

Exploring the Role of Circadian Rhythms in Sleep and Recovery: A Review Article

Sleep is essential for every living organism. Humans spend about one-third of their lives sleeping. Sleep has been studied extensively, and the role of sleep in psychological, mental, and physical well-being is established to be the best. The rhythm of the brain between wakefulness and sleep is called the circadian rhythm, which is mainly controlled by melatonin and the pineal gland. The imbalance of this rhythm can lead to devastating effects on health. Vigorous workouts close to bedtime can interfere with falling asleep. Meal timing and composition can significantly affect sleep quality. It is advised to avoid large meals, caffeine, and alcohol before bedtime. Heavy meals close to bedtime can lead to poor sleep and hormone disruption. By following these guidelines enumerated in the article, individuals can improve sleep quality and overall health. Sleep cycles, especially rapid eye movement sleep, have a profound influence on mental and physical health. Adhering to recommended sleep practices enhances bodily restoration, fortifies the immune system, and upholds metabolic equilibrium. Sleep hygiene aligned with circadian rhythms is crucial for disease prevention and well-being. Healthcare professionals should prioritize sleep optimization strategies for patient care and public health.

Role of yoga in stress management and implications in major depression disorder

Major Depressive Disorder (MDD) is one of the leading causes of disability affecting more than 340 million people and second largest contributor to global burden of disease. Chronic stress is a common risk factor and important contributor for MDD. Stress could be defined as the "perceived inability to cope". Stressful life events are shown to provoke a sequence of psychological and physiological adjustments including nervous, endocrine and immune mechanisms. Stress can lead to elevation of a variety of inflammatory cytokines and stress hormones, can cause autonomic dysfunction and imbalance in neurotransmitters. Yoga can reduce depressive symptoms by alleviating stress. Studies have shown that yoga can reduce inflammation, maintain autonomic balance and also has a role in maintaining the neurotransmitters. It has role on hypothalamic-pituitary-adrenal (HPA) axis, the peripheral nervous system including GABA, limbic system activity, inflammatory and endocrine responses. Yoga along with antidepressants can help in reducing the depressive symptoms in patient with MDD. Yoga is an ideal complementary and alternative therapy for mental health disorders.

Circadian rhythm in systemic autoimmune conditions: Potential of chrono-immunology in clinical practice: A narrative review

The circadian rhythm (CR) is a fundamental biological process regulated by the Earth's rotation and solar cycles. It plays a critical role in various bodily functions, and its dysregulation can have systemic effects. These effects impact metabolism, redox homeostasis, cell cycle regulation, gut microbiota, cognition, and immune response. Immune mediators, cycle proteins, and hormones exhibit circadian oscillations, supporting optimal immune function and defence against pathogens. Sleep deprivation and disruptions challenge the regulatory mechanisms, making immune responses vulnerable. Altered CR pathways have been implicated in diseases such as diabetes, neurological conditions, and systemic autoimmune diseases (SADs). SADs involve abnormal immune responses to self-antigens, with genetic and environmental factors disrupting self-tolerance and contributing to conditions like Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Inflammatory Myositis. Dysregulated CR may lead to increased production of pro-inflammatory cytokines, contributing to the systemic responses observed in SADs. Sleep disturbances significantly impact the quality of life of patients with SADs; however, they are often overlooked. The relationship between sleep and autoimmune conditions, whether causal or consequential to CR dysregulation, remains unclear. Chrono-immunology investigates the role of CR in immunity, offering potential for targeted therapies in autoimmune conditions. This paper provides an overview of the connections between sleep and autoimmune conditions, highlighting the importance of recognizing sleep disturbances in SADs and the need for further research into the complex relationship between the CR and autoimmune diseases.

PENN: Phase Estimation Neural Network on Gene Expression Data

With the continuous expansion of available transcriptomic data like gene expression, deep learning techniques are becoming more and more valuable in analyzing and interpreting them. The National Center for Biotechnology Information Gene Expression Omnibus (GEO) encompasses approximately 5 million gene expression datasets from animal and human subjects. Unfortunately, the majority of them do not have a recorded timestamps, hindering the exploration of the behavior and patterns of circadian genes. Therefore, predicting the phases of these unordered gene expression measurements can help understand the behavior of the circadian genes, thus providing valuable insights into the physiology, behaviors, and diseases of humans and animals. In this paper, we propose a novel approach to predict the phases of the un-timed samples based on a deep neural network architecture. It incorporates the potential periodic oscillation information of the cyclic genes into the objective function to regulate the phase estimation. To validate our method, we use mouse heart, mouse liver and temporal cortex of human brain dataset. Through our experiments, we demonstrate the effectiveness of our proposed method in predicting phases and uncovering rhythmic pattern in circadian genes.

Circadian rhythm as a key player in cancer progression as well as a therapeutic target in HER2-positive advanced gastric cancer treatment

Gastric cancer is one of the most common cancer types with less than one year prognosis in metastatic disease, which poses a huge disease burden. One of the key players in poor prognosis is human epidermal growth factor receptor 2 (HER2), which also contributes to the pathogenesis of HER2-positive advanced gastric cancer. Trastuzumab is used as first-line chemotherapy that targets the expression of HER2, however, trastuzumab resistance is an inevitable major problem. To overcome this problem, readjustment of the circadian system may play a crucial role, as dysregulation in the expression of circadian clock genes has been observed in tumors. Therefore, pharmacological modulation of clock components can be considered for better efficacy of trastuzumab. In this review, we discuss the association of circadian clock with cancer progression, development, and treatment. Metformin-based chronotherapy can disrupt BMAL1-CLOCK-PER1-HK2 axis, thereby affecting glycolysis oscillation to overcome trastuzumab resistance in HER2-positive advanced gastric cancer.

The role of circadian clock-controlled mitochondrial dynamics in diabetic cardiomyopathy

Diabetes mellitus is a metabolic disease with a high prevalence worldwide, and cardiovascular complications are the leading cause of mortality in patients with diabetes. Diabetic cardiomyopathy (DCM), which is prone to heart failure with preserved ejection fraction, is defined as a cardiac dysfunction without conventional cardiac risk factors such as coronary heart disease and hypertension. Mitochondria are the centers of energy metabolism that are very important for maintaining the function of the heart. They are highly dynamic in response to environmental changes through mitochondrial dynamics. The disruption of mitochondrial dynamics is closely related to the occurrence and development of DCM. Mitochondrial dynamics are controlled by circadian clock and show oscillation rhythm. This rhythm enables mitochondria to respond to changing energy demands in different environments, but it is disordered in diabetes. In this review, we summarize the significant role of circadian clock-controlled mitochondrial dynamics in the etiology of DCM and hope to play a certain enlightening role in the treatment of DCM.

Redox Regulatory Changes of Circadian Rhythm by the Environmental Risk Factors Traffic Noise and Air Pollution

Significance: Risk factors in the environment such as air pollution and traffic noise contribute to the development of chronic noncommunicable diseases. Recent Advances: Epidemiological data suggest that air pollution and traffic noise are associated with a higher risk for cardiovascular, metabolic, and mental disease, including hypertension, heart failure, myocardial infarction, diabetes, arrhythmia, stroke, neurodegeneration, depression, and anxiety disorders, mainly by activation of stress hormone signaling, inflammation, and oxidative stress. Critical Issues: We here provide an in-depth review on the impact of the environmental risk factors air pollution and traffic noise exposure (components of the external exposome) on cardiovascular health, with special emphasis on the role of environmentally triggered oxidative stress and dysregulation of the circadian clock. Also, a general introduction on the contribution of circadian rhythms to cardiovascular health and disease as well as a detailed mechanistic discussion of redox regulatory pathways of the circadian clock system is provided. Future Directions: Finally, we discuss the potential of preventive strategies or "chrono" therapy for cardioprotection. Antioxid. Redox Signal. 37, 679-703.

Exploring polygenic-environment and residual-environment interactions for depressive symptoms within the UK Biobank

Substantial advances have been made in identifying genetic contributions to depression, but little is known about how the effect of genes can be modulated by the environment, creating a gene-environment interaction. Using multivariate reaction norm models (MRNMs) within the UK Biobank (N = 61294-91644), we investigate whether the polygenic and residual variance components of depressive symptoms are modulated by 17 a priori selected covariate traits-12 environmental variables and 5 biomarkers. MRNMs, a mixed-effects modelling approach, provide unbiased polygenic-covariate interaction estimates for a quantitative trait by controlling for outcome-covariate correlations and residual-covariate interactions. A continuous depressive symptom variable was the outcome in 17 MRNMs-one for each covariate trait. Each MRNM had a fixed-effects model (fixed effects included the covariate trait, demographic variables, and principal components) and a random effects model (where polygenic-covariate and residual-covariate interactions are modelled). Of the 17 selected covariates, 11 significantly modulate deviations in depressive symptoms through the modelled interactions, but no single interaction explains a large proportion of phenotypic variation. Results are dominated by residual-covariate interactions, suggesting that covariate traits (including neuroticism, childhood trauma, and BMI) typically interact with unmodelled variables, rather than a genome-wide polygenic component, to influence depressive symptoms. Only average sleep duration has a polygenic-covariate interaction explaining a demonstrably nonzero proportion of the variability in depressive symptoms. This effect is small, accounting for only 1.22% (95% confidence interval: [0.54, 1.89]) of variation. The presence of an interaction highlights a specific focus for intervention, but the negative results here indicate a limited contribution from polygenic-environment interactions.

Alignment between glioblastoma internal clock and environmental cues ameliorates survival in Drosophila

Virtually every single living organism on Earth shows a circadian (i.e. "approximately a day") internal rhythm that is coordinated with planet rotation (i.e. 24 hours). External cues synchronize the central clock of the organism. Consequences of biological rhythm disruptions have been extensively studied on cancer. Still, mechanisms underlying these alterations, and how they favor tumor development remain largely unknown. Here, we show that glioblastoma-induced neurodegeneration also causes circadian alterations in Drosophila. Preventing neurodegeneration in all neurons by genetic means reestablishes normal biological rhythms. Interestingly, in early stages of tumor development, the central pacemaker lengthens its period, whereas in later stages this is severely disrupted. The re-adjustment of the external light:dark period to longer glioblastoma-induced internal rhythms delays glioblastoma progression and ameliorates associated deleterious effects, even after the tumor onset.

Night shift work characteristics are associated with several elevated metabolic risk factors and immune cell counts in a cross-sectional study

Night shift work is associated with increased health risks. Here we examined the association of metabolic risk factors and immune cell counts, with both night shift work and particular characteristics thereof: frequency, duration and consecutive night shifts. We performed a cross-sectional study using data from 10,201 non-shift workers and 1062 night shift workers of the Lifelines Cohort study. Linear regression analyses, adjusted for demographic, lifestyle and occupational factors, were used to study associations of night shift work characteristics with metabolic risk factors and immune cell counts. Night shift workers had an increased BMI, waist circumference and immune cell counts compared to non-shift workers. This was especially seen in night shift workers who had a higher frequency of night shifts per month (≥ 5: BMI: B = 0.81 kg/m² (95%-CI = 0.43–1.10); waist circumference: B = 1.58 cm (95%-Cl = 0.34–1.71; leukocytes: B = 0.19 × 10⁹ cells/L (95%-CI = 0.04–0.34 × 10⁹)) and worked more consecutive night shifts (> 3: BMI: B = 0.92 kg/m² (95%-CI = 0.41–1.43); waist circumference: B = 1.85 cm (95%-Cl = 0.45–3.24); leukocytes: B = 0.32 × 10⁹ cells/L (95%-CI = 0.09–0.55 × 10⁹)). This association was less pronounced in long-term night shift workers (≥ 20 years). Our findings provide evidence for the association between night shift work characteristics and BMI, waist circumference and leukocytes (including, monocytes, lymphocytes, and basophil granulocytes).

Bright Light Therapy for Parkinson Disease: A Literature Review and Meta-Analysis of Randomized Controlled Trials

Simple Summary

Parkinson’s disease (PD) is a common neurodegenerative disease that manifests as motor dysfunction and nonmotor symptoms (NMSs). Apart from motor symptoms, NMSs include sleep disorders, neuropsychiatric problems, and cognitive impairment, which negatively influence patients’ daily lives and caregivers. Disturbances of the sleep cycle also worsen overall health, causing dysregulation of cortisol and melatonin secretion. Furthermore, bright light therapy (BLT) is a well-known treatment for circadian rhythm sleep disorders, seasonal affective disorders, and dementia-related sleep disturbances under the regulation of circadian rhythm by melatonin, a chronological pacemaker. BLT is also applied to treat depressive symptoms and bipolar disorder through unknown mechanisms. The present study, at first, conducted a literature review, which found that a few non-controlled studies demonstrated improvements in motor symptoms and NMSs in PD. Secondly, the present study performed a meta-analysis of the randomized controlled trials which treated the PD patients with BLT. The results revealed that BLT nonsignificantly alleviated symptoms of depression and sleep disorders in patients with PD. However, the inconsistency between BLT protocols, such as varied timing, dosages, and treatment durations, may render BLT’s efficacy challenging to demonstrate, and future RCTs must be obtained.

Abstract

Sleep disorders and depression are significant nonmotor symptoms (NMSs) of Parkinson disease (PD). However, few effective, evidence-proven medical treatments are available for alleviating these symptoms. Bright light therapy (BLT) is a well-established treatment for circadian rhythm sleep disorders and seasonal affective disorder. The present study conducted a literature review for the effect of BLT on PD, especially a meta-analysis of randomized controlled trials (RCTs). We searched for studies using the PubMed and Cochrane Library databases. The major outcomes were the effects on sleep and depression. The effect on motor symptoms was also analyzed as a secondary outcome. This study was registered with PROSPERO (CRD42020204454). Six studies were included in the literature review only, and the other five RCTs were included in the meta-analysis. Despite the positive effects of BLT on PD patients, which were demonstrated in noncontrolled studies, in the meta-analysis of the RCTs, BLT did not significantly improve the depressive symptoms (standardized mean difference (SMD): −0.15, 95% confidence interval (CI): −0.48 to 0.17, p = 0.36) and excessive daytime sleepiness (EDS) (SMD: −0.12, 95% CI: −0.49 to 0.25, p = 0.53) in PD patients. Regarding motor symptoms, no significant beneficial effects were conferred (SMD: −0.11, 95% CI: −0.44 to 0.21, p = 0.49). In conclusion, BLT did not significantly alleviate depression and sleepiness. The inconsistency between BLT protocols, such as the varied timing, dosages, and treatment durations, may render BLT’s efficacy difficult to demonstrate. The small effect size obtained from the present meta-analysis indicates that future RCTs are necessary, for which BLT protocols are standardized and more patients are enrolled to determine whether a significant therapeutic benefit was conferred.

Study of Post-COVID-19 Syndrome in Saudi Arabia

Background Post-COVID-19 syndrome may be predisposed by organ damage as a complication of COVID-19. Patients may experience persistent symptoms after recovering from their initial illness. Objectives To identify manifestations and predisposing factors for post-COVID-19 syndrome in Saudi Arabia. Methods A cross-sectional study was conducted from May 2021 through June 2021 using an online structured pre-coded closed-ended, pilot-tested questionnaire in Arabic. It included male and female inhabitants of Saudi Arabia aged 18 years and above with a past history of COVID-19 infection. Descriptive statistics were carried out for all variables. A univariate analysis Chi-square test and independent t-test were used. A p-value of less than 0.05 was considered significant. Results A total of 85.3% of post-COVID-19 cases had general manifestations: 77.3% had musculoskeletal and joint complaints, 61.3% had mental and psychological problems, 58.7% had gastrointestinal manifestations, 44% had renal complaints, 41.3% had respiratory complaints, and 36.0% had cardiovascular symptoms. Gender, age, smoking, BMI, associated morbid condition, number of previous COVID-19 attacks, the severity of illness, place of treatment, and complications of COVID-19 due to treatment or hospitalization were significantly correlated with the occurrence of post-COVID-19 syndrome. Conclusion Post-COVID-19 syndrome could be manifested by fatigue, malaise, myalgia, joint pain, depression, anxiety, sleep, memory and concentration disturbances, cough, dyspnea, palpations, arrhythmias, and chest pain. It may be influenced by male gender, smoking, old age, high BMI, comorbidities, and past COVID-19 attacks with regard to the number, place of treatment, and occurrence of complications.

Mental health consequences of infections by coronaviruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

BACKGROUND

Anxiety and stress like mental illnesses are the common outcomes of viral epidemics and pandemics. Novel coronavirus disease 2019 (COVID-19) outbreak caused by the severe acute respiratory syndrome coronavirus virus 2 (SARS-CoV-2) was first reported in Wuhan, China, and then spread all over the world in a short time.

OBJECTIVES

To highlight and discuss the impact of COVID-19 pandemic on mental or psychological health.

METHOD

Literature search and collection of the information were performed using PubMed, the reports from the World health organization, and the Center for disease control and prevention.

RESULTS

COVID-19 infection has already been declared as a global pandemic, which in association with infodemic has increased the risk of psychiatric/psychological disorders. A large population of the world is prone to develop anxiety, depressive disorders, and other mental abnormalities. Therefore, timely psychological interventions and preventive strategies are required. Moreover, the infection has been reported to be linked with cerebrovascular conditions; therefore, patients with underlying cerebrovascular diseases should be given attention.

CONCLUSION

COVID-19-mediated mental health complications and cerebrovascular conditions may cause a huge burden on healthcare communities in the future. Therefore, timely intervention and the development or application of preventive strategies are required to decrease the risk of neurological consequences.

Coronaviruses disease 2019 (COVID-19): Causative agent, mental health concerns, and potential management options

Coronavirus disease-2019 (COVID-19) pandemic started from Wuhan, China has infected more than 6.7 million individuals and killed more than 390,000 individuals globally. Due to the higher transmissibility and infectiousness, asymptomatic infection, and lack of effective treatment options and vaccine, fatalities and morbidities are increasing day by day globally. Despite physical health consequences, COVID-19 pandemic has created stress and anxiety, as result there is an increased risk of mental illnesses both in the infected and normal individuals. To eradicate these risks, it is necessary to determine the COVID-19 zoonotic source of transmission to humans and clinical manifestations in infected individuals. Although, identification or development of the highly effective therapeutic agents is necessary, however, development of protective strategies against the COVID-19 by enhancing immune responses will be an asset in the current scenarios of the COVID-19 pandemic. In this paper, we discuss the transmission, health consequences, and potential management (therapeutic and preventive) options for COVID-19 disease.

Effects of constant light exposure on sphingolipidomics and progression of NASH in high-fat-fed rats

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is a growing public health concern worldwide. With the progression of urbanization, light pollution is becoming an inevitable risk factor for NAFLD. However, the role of light pollution on NAFLD is insufficiently understood, and the underlying mechanism remains unclear. The present study explored effects of constant light exposure on NAFLD and elucidated its related mechanisms.

METHODS

Thirty-two male Sprague Dawley rats were divided into four groups (n = 8 each): (i) rats on a normal diet exposed to standard light-dark cycle (ND-LD); (ii) rats on a normal diet exposed to constant light (ND-LL); (iii) rats on a high-fat diet exposed to standard light-dark cycle (HFD-LD); and (iv) and rats on a high-fat diet exposed to constant light (HFD-LL). After 12 weeks of treatment, rats were sacrificed and pathophysiological assessments were performed. Targeted lipidomics was used to measure sphingolipids, including ceramides, glucosylceramides, and lactosylceramides, sphingomyelins, and sphingosine-1-phosphates in plasma and liver tissues.

RESULTS

In normal chow rats, constant light exposure led to glucose abnormalities and dyslipidemia. In high-fat-fed rats, constant light exposure exacerbated glucose abnormalities, dyslipidemia, insulin resistance, and inflammation and aggravated steatohepatitis. Compared with HFD-LD rats, HFD-LL had decreased plasma sphingosine-1-phosphate and elevated liver concentrations of total ceramide and specific ceramide species (ceramide d18:0/24:0, ceramide d18:1/22:0, ceramide d18:1/24:0, and ceramide d18:1/24:1), which were associated with increased hepatocyte apoptosis.

CONCLUSIONS

Constant light exposure causes dysregulation of sphingolipids and promotes steatohepatitis in high-fat-fed rats.

Using Circadian Rhythm Patterns of Continuous Core Body Temperature to Improve Fertility and Pregnancy Planning

Objective

Review relationships among circadian clocks, core body temperature (CBT), and fertility in women.

Methods

Scoping literature review.

Results

Circadian clocks are a ubiquitous adaptation to the most predictable environmental events - the daily cycles of light and dark. Core body temperature (CBT) also follows a circadian rhythm. Additionally, CBT is tightly controlled by a combination of neuronal circuits that begin in the hypothalamus and involve many other portions of the brain as well as a wide range of peripheral mechanisms. In women with normal reproductive function, the diurnal temperature pattern for CBT is strongly influenced by the menstrual cycle of reproductive hormones, primarily estradiol and progesterone, which modulate the activity of hypothalamic neural circuits involved in body temperature control, resulting in an infradian CBT rhythm.

Conclusions

Analysis of CBT via continuous recording reveals patterns in the interactions of circadian and infradian CBT rhythms capable of accurately predicting the fertility window and hormonal patterns suggesting oligo-ovulation and subfertility. New wearable technologies can facilitate employment of hormone-associated changes in CBT for pregnancy planning and offer clinical insight to infertility and menopause.

Circadian activity rhythms and fatigue of adolescent cancer survivors and healthy controls: a pilot study

STUDY OBJECTIVES

The primary objective of this study was to compare circadian activity rhythms (CARs) of adolescents within 5 years of completing cancer treatment (survivors) with that of healthy adolescent controls. Secondary objectives were to explore differences in the relationship of CARs and fatigue between survivors and controls and between early survivors (<12 months posttreatment) and late survivors (≥12 months posttreatment).

METHODS

Twenty-nine survivors and 30 controls, aged 13-18 years, participated in this prospective, descriptive pilot study. Adolescents and their parents completed a baseline measure of adolescents' fatigue. Adolescents wore a wrist actigraph continuously for 7 days and concurrently kept a sleep diary. Activity data recorded by actigraphy were fitted to an extended cosine model to calculate six CAR variables: acrophase, amplitude, midline estimating statistic of rhythm (MESOR), up-MESOR, down-MESOR, and F-statistic. Linear mixed models explored the relationship between CARs and fatigue.

RESULTS

There were no group differences on CAR or fatigue measures. Among survivors, earlier down-MESOR was associated with greater parent-reported fatigue (P = .020), and earlier acrophase (P = .023) and up-MESOR (P = .025) were associated with greater adolescent-reported fatigue. Significant CAR-by-time posttreatment interaction effects were found on fatigue between early and late survivors. Among controls, greater parent-reported fatigue was associated with greater MESOR (P = .0495).

CONCLUSIONS

Survivors within the first 5 years posttreatment were similar to controls in CARs and fatigue, suggesting robust recovery of circadian rhythms posttreatment. Different CAR characteristics were associated with fatigue in survivors and controls. Time posttreatment influenced the relationship between CARs and fatigue for survivors, with significant effects only for early survivors.

The Feasibility of Measuring Sleep and Circadian Characteristics in Adults with Inflammatory Bowel Disease

Interest in sleep and circadian research in inflammatory bowel disease (IBD) (Crohn's disease and ulcerative colitis) is growing; however, few studies have objectively measured sleep or circadian rhythms in people with these conditions. The purpose was to determine the feasibility of the use of wrist actigraphy, electronic sleep/activity diaries, and participant-collected saliva among adults with both active and inactive IBD. We conducted a 10-day feasibility study of adults aged 18 years to 60 years with IBD. We measured sleep and rest-activity rhythms with wrist actigraphy, self-reported sleep/activity using electronic diaries, and participant-collected saliva to compute salivary dim light melatonin onset. All 37 (100%) participants wore the wrist actigraphs, 91.8% (N = 34) participants completed at least 15 of the 18 electronic diaries, and 34 (91.9%) completed the saliva collection. It is feasible to use wrist actigraphy and electronic sleep/activity diaries in adult participants with inflammatory bowel disease.

Extracellular Acidosis Promotes Metastatic Potency via Decrease of the BMAL1 Circadian Clock Gene in Breast Cancer

Circadian oscillation is an essential process that influences many physiological and biological mechanisms and a decrease of circadian genes is associated with many diseases such as cancer. Despite many efforts to identify the detailed mechanism for decreasing circadian genes and recovering reduced circadian genes in cancer, it is still largely unknown. We found that BMAL1 was reduced in tumor hypoxia-induced acidosis, and recovered by selectively targeting acidic pH in breast cancer cell lines. Surprisingly, BMAL1 was reduced by decrease of protein stability as well as inhibition of transcription under acidosis. In addition, melatonin significantly prevented acidosis-mediated decrease of BMAL1 by inhibiting lactate dehydrogenase-A during hypoxia. Remarkably, acidosis-mediated metastasis was significantly alleviated by BMAL1 overexpression in breast cancer cells. We therefore suggest that tumor hypoxia-induced acidosis promotes metastatic potency by decreasing BMAL1, and that tumor acidosis could be a target for preventing breast cancer metastasis by sustaining BMAL1.

Influence of mental stress and environmental toxins on circadian clocks: Implications for redox regulation of the heart and cardioprotection

Risk factors in the environment such as air pollution and mental stress contribute to the development of chronic non-communicable disease. Air pollution was identified as the leading health risk factor in the physical environment, followed by water pollution, soil pollution/heavy metals/chemicals and occupational exposures, however neglecting the non-chemical environmental health risk factors (e.g. mental stress and noise). Epidemiological data suggest that environmental risk factors are associated with higher risk for cardiovascular, metabolic and mental diseases, including hypertension, heart failure, myocardial infarction, diabetes, arrhythmia, stroke, depression and anxiety disorders. We provide an overview on the impact of the external exposome comprising risk factors/exposures on cardiovascular health with a focus on dysregulation of stress hormones, mitochondrial function, redox balance and inflammation with special emphasis on the circadian clock. Finally, we assess the impact of circadian clock dysregulation on cardiovascular health and the potential of environment-specific preventive strategies or "chrono" therapy for cardioprotection. LINKED ARTICLES: This article is part of a themed issue on Risk factors, comorbidities, and comedications in cardioprotection. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.23/issuetoc.

Impact of chronically alternating light-dark cycles on circadian clock mediated expression of cancer (glioma)-related genes in the brain

Disruption of the circadian rhythm is a risk factor for cancer, while glioma is a leading contributor to mortality worldwide. Substantial efforts are being undertaken to decrypt underlying molecular pathways. Our understanding of the mechanisms through which disrupted circadian rhythm induces glioma development and progression is incomplete. We, therefore, examined changes in the expression of glioma-related genes in the mouse brain after chronic jetlag (CJL) exposure. A total of 22 candidate tumor suppressor (n= 14) and oncogenes (n= 8) were identified and analyzed for their interaction with clock genes. Both the control and CJL groups were investigated for the expression of candidate genes in the nucleus accumbens, hippocampus, prefrontal cortex, hypothalamus, and striatum of wild type, Bmal1-/- and Cry1/2 double knockout male mice. We found significant variations in the expression of candidate tumor suppressor and oncogenes in the brain tissues after CJL treatment in the wild type, Bmal1-/- and Cry1/2 double knockout mice. In response to CJL treatment, some of the genes were regulated in the wild type, Bmal1-/- and Cry1/2 similarly. However, the expression of some of the genes indicated their association with the functional clock. Overall, our result suggests a link between CJL and gliomas risk at least partially dependent on the circadian clock. However, further studies are needed to investigate the molecular mechanism associated with CJL and gliomas.

Aging and the clock: Perspective from flies to humans

Endogenous circadian oscillators regulate molecular, cellular and physiological rhythms, synchronizing tissues and organ function to coordinate activity and metabolism with environmental cycles. The technological nature of modern society with round-the-clock work schedules and heavy reliance on personal electronics has precipitated a striking increase in the incidence of circadian and sleep disorders. Circadian dysfunction contributes to an increased risk for many diseases and appears to have adverse effects on aging and longevity in animal models. From invertebrate organisms to humans, the function and synchronization of the circadian system weakens with age aggravating the age-related disorders and pathologies. In this review, we highlight the impacts of circadian dysfunction on aging and longevity and the reciprocal effects of aging on circadian function with examples from Drosophila to humans underscoring the highly conserved nature of these interactions. Additionally, we review the potential for using reinforcement of the circadian system to promote healthy aging and mitigate age-related pathologies. Advancements in medicine and public health have significantly increased human life span in the past century. With the demographics of countries worldwide shifting to an older population, there is a critical need to understand the factors that shape healthy aging. Drosophila melanogaster, as a model for aging and circadian interactions, has the capacity to facilitate the rapid advancement of research in this area and provide mechanistic insights for targeted investigations in mammals.