Clock genes alterations and endocrine disorders

Deficiency of circadian clock gene Bmal1 exacerbates noncanonical inflammasome-mediated pyroptosis and lethality via Rev-erbα-C/EBPβ-SAA1 axis

Circadian arrhythmia has been linked to increased susceptibility to multiple inflammatory diseases, such as sepsis. However, it remains unclear how disruption of the circadian clock modulates molecular aspects of innate immune responses, including inflammasome signaling. Here, we examined the potential role of the circadian clock in inflammasome-mediated responses through myeloid-specific deletion of BMAL1, a master circadian clock regulator. Intriguingly, Bmal1 deficiency significantly enhanced pyroptosis of macrophages and lethality of mice under noncanonical inflammasome-activating conditions but did not alter canonical inflammasome responses. Transcriptome analysis of enriched peritoneal myeloid cells revealed that Bmal1 deficiency led to a marked reduction in Rev-erbα expression at steady state and a significant increase in serum amyloid A1 (SAA1) expression upon poly(I:C) stimulation. Notably, we found that the circadian regulator Rev-erbα is critical for poly(I:C)- or interferon (IFN)-β-induced SAA1 production, resulting in the circadian oscillation pattern of SAA1 expression in myeloid cells. Furthermore, exogenously applied SAA1 markedly increased noncanonical inflammasome-mediated pyroptosis of macrophages and lethality of mice. Intriguingly, our results revealed that type 1 IFN receptor signaling is needed for poly(I:C)- or IFN-β-induced SAA1 production. Downstream of the type 1 IFN receptor, Rev-erbα inhibited the IFN-β-induced association of C/EBPβ with the promoter region of Saa1, leading to the reduced transcription of Saa1 in macrophages. Bmal1-deficient macrophages exhibited enhanced binding of C/EBPβ to Saa1. Consistently, the blockade of Rev-erbα by SR8278 significantly increased poly(I:C)-stimulated SAA1 transcription and noncanonical inflammasome-mediated lethality in mice. Collectively, our data demonstrate a potent suppressive effect of the circadian clock BMAL1 on the noncanonical inflammasome response via the Rev-erbα-C/EBPβ-SAA1 axis.

Characteristics of insulin resistance in Korean adults from the perspective of circadian and metabolic sensing genes

BACKGROUND

The biological clock allows an organism to anticipate periodic environmental changes and adjust its physiology and behavior accordingly.

OBJECTIVE

This retrospective cross-sectional study examined circadian gene polymorphisms and clinical characteristics associated with insulin resistance (IR).

METHODS

We analyzed data from 1,404 Korean adults aged 30 to 55 with no history of cancer and cardio-cerebrovascular disease. The population was classified according to sex and homeostasis model assessment of insulin resistance (HOMA-IR) values. Demographics, anthropometric and clinical characteristics, and single nucleotide polymorphisms (SNPs) were analyzed with respect to sex, age, and HOMA-IR values. We used association rule mining to identify sets of SNPs from circadian and metabolic sensing genes that may be associated with IR.

RESULTS

Among the subjects, 15.0% of 960 women and 24.3% of 444 men had HOMA-IR values above 2. Most of the parameters differed significantly between men and women, as well as between the groups with high and low insulin sensitivity. Body fat mass of the trunk, which was significantly higher in insulin-resistant groups, had a higher correlation with high sensitivity C-reactive protein and hemoglobin levels in women, and alanine aminotransferase and aspartate aminotransferase levels in men. Homozygous minor allele genotype sets of SNPs rs17031578 and rs228669 in the PER3 gene could be more frequently found among women with HOMA-IR values above 2 (p = .014).

CONCLUSION

Oxidative stress enhanced by adiposity and iron overload, which may also be linked to NRF2 and PER3-related pathways, is related to IR in adulthood. However, due to the small population size in this study, more research is needed.

Genetic Variants in CD36 Involved in Fat Taste Perception: Association with Anthropometric and Clinical Parameters in Overweight and Obese Subjects Affected by Type 2 Diabetes or Dysglycemia-A Pilot Study

Obesity and overweight represent a growing health problem worldwide. Genes regulating the intake and metabolism of different nutrients can positively or negatively influence the efficacy of nutritional interventions against obesity and its complications. The aim of this study was to assess changes in anthropometric and clinical parameters and the adherence to a Mediterranean diet (MedDiet) over time in relation to nutrigenetic variants in overweight or obese subjects affected by Type 2 Diabetes (T2D) or dysglycemia, who were included in a nutritional program. A total of 23 subjects were included in this study. Clinical parameters, physical activity levels, and the adherence to a MedDiet were evaluated at baseline, at 6 (T6), and at 12 months (T12) during and after a diet/lifestyle intervention. In a single blood sample from each subject, rs1984112 (A>G) and rs1761667 (G>A) in CD36; rs7950226 (G>A) in BMAL1; and rs1801260 (A>G), rs4864548 (A>G), and rs3736544 (G>A) in CLOCK were genotyped with Real-Time PCR. Significant associations were observed between CD36 rs1761667 and weight (p = 0.025), hip circumference (p = 0.042), triglycerides (p = 0.047), and HbA1c (p = 0.012) at baseline. Moreover, the genotype AA in CD36 rs1761667 was significantly associated with a lower BMI when compared to G carriers at baseline, at T6, and also at T12. In addition, subjects with the AA genotype at CD36 rs1984112 had significantly lower levels of HbA1c (p = 0.027) than the GG and AG genotypes at baseline. These results show that variants in CD36 can have an impact on anthropometric and clinical parameters in overweight or obese subjects affected by T2D or dysglycemia, and that it might influence the success of the diet/lifestyle intervention.

A Review of Evidence for the Involvement of the Circadian Clock Genes into Malignant Transformation of Thyroid Tissue

(1) Background: In 2013, the results of a pioneer study on abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in cancerous thyroid nodules was published. In the following years, new findings suggesting the involvement of circadian clockwork dysfunction into malignant transformation of thyroid tissue were gradually accumulating. This systematic review provides an update on existing evidence regarding the association of these genes with thyroid tumorigenesis. (2) Methods: Two bibliographic databases (Scopus and PubMed) were searched for articles from inception to 20 March 2023. The reference lists of previously published (nonsystematic) reviews were also hand-searched for additional relevant studies. (3) Results: Nine studies published between 2013 and 2022 were selected. In total, 9 of 12 tested genes were found to be either up- or downregulated. The list of such genes includes all families of core circadian clock genes that are the key components of three transcriptional-translational feedback loops of the circadian clock mechanism (BMAL1, CLOCK, NPAS2, RORα, REV-ERBα, PERs, CRYs, and DECs). (4) Conclusions: Examination of abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in thyroid tissue can help to reduce the rate of inadequate differential preoperative diagnosis for thyroid carcinoma.

Interplay Among the Daily Rhythm of the Thyroid Hormones, Uncoupling Protein 1 and the Clock Gene Per2 in Horses

During husbandry, domestic animals are exposed to many factors that can influence their circadian physiology organization leading to an increase in animals' discomfort. Thermal homeostasis is at the basis of animal wellness, the aim of the present study was to investigate the daily fluctuation of serum concentrations of 3,5,3'-triiodothyronine (T3) and thyroxine (T4) in association with the daily fluctuation of uncoupling protein 1 (UCP1) and clock gene Per2 in healthy horses housed in individual box, to improve the knowledge on this matter. Seven clinically healthy female Italian Saddle horses (8-10 years old, 510 ± 32 kg), were housed in individual boxes under natural photoperiod and environmental temperature and humidity. Blood samples were collected at 4-hour intervals over a 48-hour period, for the assessment of T3, T4, UCP1, and clock gene Per2. The application of two-way analysis of variance (ANOVA) on raw data showed a statistically significant effect of time of day on all studied parameters. A robust daily rhythm of T3, T4, and Per2 was observed. T3 showed a diurnal rhythm, with the acrophase at about 5 hours after sunrise, T4 acrophase was observed in the middle of the scotophase, Per2 acrophase was observed close to sunrise. In conclusion, we can claim that in horses kept under natural environmental conditions and not subjected to thermal stress, there is a daily rhythm of thyroid hormones associated with a daily rhythm of Per2 expression in the peripheral blood, and UCP1 remained constant during the two days.

The circadian rhythm key gene ARNTL2: a novel prognostic biomarker for immunosuppressive tumor microenvironment identification and immunotherapy outcome prediction in human cancers

Background

Aryl hydrocarbon receptor nuclear translocator-like 2 (ARNTL2) belongs to the b HLH- PAS domain transcription factor family and is one of the key clock genes that control the circadian rhythm. ARNTL2 plays an important role in human biological functions. However, its role in various tumors, especially in the tumor immune microenvironment (TIME) and immunotherapy, remains unclear.

Methods

We integrated data from cancer patients from multiple databases, including the Cancer Genome Atlas, Cancer Cell Lineage Encyclopedia, Genotype Tissue Expression, Human Protein Atlas, cBioPortal, TIMER, and ImmuCellAI, with data from a large clinical study, three immunotherapy cohorts, and in vitro experiments to investigate the involvement of ARNTL2 expression in cancer prognosis and immune response.

Results

ARNTL2 displayed abnormal expression within most malignant tumors, and is significantly associated with poorer survival and pathologic staging. Through gene-set enrichment analysis (GSEA) and gene-set variation analysis (GSVA), we found that ARNTL2 not only regulates cell cycle-related functions to promote cell proliferation but also regulates autoimmunity-related functions of the innate and adaptive immune systems, and other immune-related signaling pathways. In addition, ARNTL2 overexpression contributes to an immunosuppressive tumor microenvironment that plays a key role in immunosuppression-related features, such as the expression of immunosuppression-related genes and pathways and the number of immunosuppressive-infiltrating cells, including regulatory T cells (Tregs), tumor-associated macrophages (TAMs), and cancer-associated fibroblasts (CAFs). The group of patients with low ARNTL2 expression who received immune checkpoint inhibitors (ICI) therapy had better response rates and longer survival when compared to those with high ARNTL2 expression.

Conclusion

The findings of this study suggest that ARNTL2 is a potential human oncogene that plays an important role in tumorigenesis and cancer immunity. Elevated ARNTL2 expression indicates an immunosuppressive tumor microenvironment. Targeting ARNTL2 in combination with ICI therapy could bring more significant therapeutic benefits to patients with cancer. Our study sheds light on the remarkable potential of ARNTL2 in tumor immunity and provides a novel perspective for anti-tumor strategies.

The Circadian Clocks, Oscillations of Pain-Related Mediators, and Pain

The circadian clock is a biochemical oscillator that is synchronized with solar time. Normal circadian rhythms are necessary for many physiological functions. Circadian rhythms have also been linked with many physiological functions, several clinical symptoms, and diseases. Accumulating evidence suggests that the circadian clock appears to modulate the processing of nociceptive information. Many pain conditions display a circadian fluctuation pattern clinically. Thus, the aim of this review is to summarize the existing knowledge about the circadian clocks involved in diurnal rhythms of pain. Possible cellular and molecular mechanisms regarding the connection between the circadian clocks and pain are discussed.

Sarm1 Regulates Circadian Rhythm Disorder in Alzheimer's Disease in Mice

BACKGROUND

Sarm1 (Sterile alpha and TIR motif-containing 1) is a key protein that regulates neurodegenerative pathologies. Alzheimer's disease (AD) is highly associated with neurodegenerative lesions and biorhythmic disturbances.

OBJECTIVE

This study aims to decipher the role of Sarm1 in AD-induced circadian rhythm disturbances and AD progression.

METHODS

Open field and water maze tests were used to assess the cognitive function of mice. Thioflavin-S staining was used to assess amyloid-β (Aβ) plaque deposition in the hippocampus and cortex. Rhythmic waveform of home cage activity and temperature was recorded to evaluate circadian rhythm. Expression of clock molecules including Bmal1 and Per2 in the hippocampus were analyzed using western blot and real-time PCR. Further, HT22 cells with Sam1 knockout were treated with Aβ 31-35 treatment to initiate circadian rhythm disorder in the cellular level to assess the changes in Bmal1 and Per2.

RESULTS

Our data suggested that Sarm1 deficiency rescued cognitive disorder, decreased Aβ plaque deposition in the hippocampus and cortex, inhibited astrocyte activation, improved circadian rhythm, altered clock molecule expression in the cortex and hippocampus in APP/PS1 mice.

CONCLUSION

Sarm1 attenuates circadian rhythm disturbances and reduces AD progression. These data support the potential use of Sarm1 as a therapeutic target to improve circadian rhythm to impede AD progression.

Neuroprotective effect of thyroid hormones on methamphetamine-induced neurotoxicity via cell surface receptors

Thyroid hormones (THs) have an essential role in normal brain development and function. Methamphetamine (MA) is a widely abused psychostimulant that induces irreversible damages to neuronal cells. In the current study, we used rat primary hippocampal neurons (PHNs) to investigate the neuroprotective effect of THs against MA neurotoxicity. PHNs were prepared from 18-day rat embryos and cell viability was assessed using MTT assay, following treatment with various concentrations of MA, T3, T4 or tetrac, an integrin αvβ3 cell surface receptor antagonist. Our results showed that 7 mM MA induced an approximately 50 % reduction in the PHNs viability. Treatment with 800 nM T3 or 8 μM T4 protected PHNs against MA toxicity, an effect which was blocked in the presence of tetrac. These findings suggest that THs protect PHNs against MA-induced cell death by the activation of integrin αvβ3 cell surface receptors. So, targeting integrin αvβ3 receptors or using THs can be considered as promising therapeutic strategies to overcome MA neurotoxicity.

Association between CLOCK gene polymorphisms and ADHD in Mexican teenagers: A comprehensive assessment

This study aimed to evaluate markers of the CLOCK gene rs1801260 and rs4864548 in Mexican adolescents, addressing clinical and biological aspects previously associated with ADHD. 347 Mexican adolescents were assessed for mental disorders, metabolic disruption and related conditions, circadian preference, as well as genotyping for the CLOCK. We found a significant association between ADHD and the AA and AG genotypes of rs1801260. Also, we identified in the ADHD group that the total Triiodothyronine and total Thyroxine values were respectively 10 ng/dl units and 0.58 ug/dl units lower in females than in males. Previously reported common variations of the CLOCK gene have been associated with ADHD like the Rs1801260 polymorphism hereby we could consider it as risk factor, but genetic, biochemical and clinical studies in the Mexican population are entailed.

Diurnal rhythms in testicular blood flow, testicular morphometry and reproductive hormones in Shiba goats

Context Testicular blood flow (TBF) is crucial for testicular function. The pattern of TBF in Shiba goats indicates seasonal variations. Aims This study aimed to investigate the effect of diurnal variations on TBF, testis volume (TV), testicular echogenicity, and reproductive hormones in goats over a 24-h period. Methods In three trials that went for three consecutive days each, 12 bucks were scanned using Triplex ultrasonography to assess the TV, pixel intensity of testicular echotexture (PIX), and Doppler indices of TBF (resistive index: RI and pulsatility index: PI) in four-time points a day (at 6.00, 12.00, 18.00, and 00.00 h). Concomitantly, the changes in circulating FSH, LH, inhibin, testosterone (T), estradiol (E2), cortisol, and melatonin were assessed. Key results Results revealed diurnal alterations in the calculated RI of TBF and the PIX of testicular parenchyma (P < 0.05). Lower RI values of the TBF were observed at 6.00 h compared to other time points. There were significant diurnal alterations in the levels of FSH (P < 0.05), LH (P < 0.05), T (P < 0.0001), E2 (P < 0.0001), cortisol (P < 0.0001), and melatonin (P < 0.0001). FSH attained a higher concentration at 18.00 h compared to 12.00 h. Concentrations of LH were significantly higher at 06.00 h compared to those at 18.00 h. Concentrations of T were significantly higher at 6.00 compared to other time points. E2 showed higher concentrations at 6.00 h and 00.00 h compared to 12.00 h and 18.00 h. On the contrary, concentrations of cortisol were significantly higher at 12.00 h and 18.00 h compared to 06.00 h and 00.00 h. The highest concentrations of melatonin were observed at 00.00 h compared to other time points, while the lowest concentrations were at 12.00 h. Conclusions Diurnal rhythm induces significant changes in TBF, testicular PIX, and circulating FSH, LH, T, E2, cortisol, and melatonin over the 24-h day. Implications The outcomes of the study are reflected in the advisability of monitoring the TBF at a fixed time a day to avoid the circadian rhythm effect.

The Association of Dietary Vitamin Intake Time Across a Day With Cardiovascular Disease and All-Cause Mortality

Background

Chrono-nutrition emphasized the importance of the intake time; however, less is known about the impact of dietary vitamin intake time on health. This study aimed to examine our hypothesis about which vitamin intake time could influence the natural course of cardiovascular disease (CVD).

Methods

A total of 27,455 adults enrolled in the National Health and Nutrition Examination Survey (NHANES) during 2003–2014 were recruited. The 12 dietary vitamin intakes in the morning, afternoon, and evening were categorized into tertiles or quartiles. Cox-proportional hazard regression models were developed to evaluate the association of vitamin intake time with CVD and all-cause mortalities.

Results

Compared with participants in the lowest quartile, participants in the highest quartile of dietary VB2 intake in the morning had significantly lowest mortality risk of CVD [hazard ratio (HR)_VB2 = 0.75, 95% CI: 0.60–0.94, p = 0.017]; whereas, participants in the highest quartile of dietary-vitamin B6 (VB6), vitamin C (VC), vitamin E (VE), and folate-equivalent consumed in the evening showed the lowest risks of CVD (HR_VB6 = 0.77, 95% CI: 0.60–0.99, p = 0.103; HR_VC = 0.80, 95% CI: 0.65–0.98, p = 0.050; HR_VE = 0.75, 95% CI: 0.56–0.99, p = 0.032; HR_{folate–equivalent} = 0.78, 95% CI: 0.63–0.97, p = 0.116) and all-cause mortalities (HR_VB6 = 0.81, 95% CI: 0.71–0.93, p = 0.006; HR_VC = 0.85, 95% CI: 0.76–0.95, p = 0.004; HR_VE = 0.84, 95% CI: 0.72–0.97, p = 0.011; HR_{folate–equivalent} = 0.80, 95% CI: 0.71–0.90, p = 0.001). Moreover, equivalently replacing 10% intake of dietary VB6, VC, VE, and folate-equivalent in the morning with evening were associated with 4% (HR_VB6 = 0.96, 95% CI: 0.92–0.99), 5% (HR_VC = 0.95, 95% CI: 0.92–0.99), 4% (HR_VE = 0.96, 95% CI: 0.91–0.99), and 5% (HR_{folate–equivalent} = 0.95, 95% CI: 0.92–0.99) lower risk of CVD mortality.

Conclusion

This study found that the optimal intake time of dietary VB2 was in the morning, and the optimal intake times of dietary VB6, VC, VE, and folate-equivalent were in the evening.

Research Opportunities in Autonomic Neural Mechanisms of Cardiopulmonary Regulation: A Report From the National Heart, Lung, and Blood Institute and the National Institutes of Health Office of the Director Workshop

This virtual workshop was convened by the National Heart, Lung, and Blood Institute, in partnership with the Office of Strategic Coordination of the Office of the National Institutes of Health Director, and held September 2 to 3, 2020. The intent was to assemble a multidisciplinary group of experts in basic, translational, and clinical research in neuroscience and cardiopulmonary disorders to identify knowledge gaps, guide future research efforts, and foster multidisciplinary collaborations pertaining to autonomic neural mechanisms of cardiopulmonary regulation. The group critically evaluated the current state of knowledge of the roles that the autonomic nervous system plays in regulation of cardiopulmonary function in health and in pathophysiology of arrhythmias, heart failure, sleep and circadian dysfunction, and breathing disorders. Opportunities to leverage the Common Fund's SPARC (Stimulating Peripheral Activity to Relieve Conditions) program were characterized as related to nonpharmacologic neuromodulation and device-based therapies. Common themes discussed include knowledge gaps, research priorities, and approaches to develop novel predictive markers of autonomic dysfunction. Approaches to precisely target neural pathophysiological mechanisms to herald new therapies for arrhythmias, heart failure, sleep and circadian rhythm physiology, and breathing disorders were also detailed.

Roles of clock genes in the pathogenesis of Parkinson's disease

Parkinson's disease (PD) is a common motor disorder that has become increasingly prevalent in the ageing population. Recent works have suggested that circadian rhythms disruption is a common event in PD patients. Clock genes regulate the circadian rhythm of biological processes in eukaryotic organisms, but their roles in PD remain unclear. Despite this, several lines of evidence point to the possibility that clock genes may have a significant impact on the development and progression of the disease. This review aims to consolidate recent understanding of the roles of clock genes in PD. We first summarized the findings of clock gene expression and epigenetic analyses in PD patients and animal models. We also discussed the potential contributory role of clock gene variants in the development of PD and/or its symptoms. We further reviewed the mechanisms by which clock genes affect mitochondrial dynamics as well as the rhythmic synthesis and secretion of endocrine hormones, the impairment of which may contribute to the development of PD. Finally, we discussed the limitations of the currently available studies, and suggested future potential studies to deepen our understanding of the roles of clock genes in PD pathogenesis.

Impact of sleep patterns upon female neuroendocrinology and reproductive outcomes: a comprehensive review

Sleep is vital to human bodily function. Growing evidence indicates that sleep deprivation, disruption, dysrhythmia, and disorders are associated with impaired reproductive function and poor clinical outcomes in women. These associations are largely mediated by molecular-genetic and hormonal pathways, which are crucial for the complex and time sensitive processes of hormone synthesis/secretion, folliculogenesis, ovulation, fertilization, implantation, and menstruation. Pathologic sleep patterns are closely linked to menstrual irregularity, polycystic ovarian syndrome, premature ovarian insufficiency, sub/infertility, and early pregnancy loss. Measures of success with assisted reproductive technology are also lower among women who engage in shift work, or experience sleep disruption or short sleep duration. Extremes of sleep duration, poor sleep quality, sleep disordered breathing, and shift work are also associated with several harmful conditions in pregnancy, including gestational diabetes and hypertensive disorders. While accumulating evidence implicates pathologic sleep patterns in impaired reproductive function and poor reproductive outcomes, additional research is needed to determine causality and propose therapeutic interventions.

A panel of rhythm gene polymorphisms is involved in susceptibility to type 2 diabetes mellitus and bipolar disorder

Background

Biological rhythm is closely related to health. We aimed to identify the potential correlations of rhythm gene polymorphisms to type 2 diabetes mellitus (DM) or bipolar disorder (BD), which both have many abnormal rhythmic activities, in a sample of Chinese Han origin.

Methods

A total of 136 patients with BD, 166 patients with DM, and 130 healthy controls were collected. We screened 28 single nucleotide polymorphisms (SNPs) located in rhythm genes CLOCK, ARNTL, PER2, PER3, CRY1, and CRY2 respectively. Snapshot typing technology was used for genotyping.

Results

Both the rs10832022-G and rs11022765-A allele frequencies of the ARNTL gene were significantly higher in patients with DM than in those with BD (corrected P=0.03, 0.004, respectively). The frequency of rs10832022-G, rs1022765-A, and rs11022762-T haplotypes, which was significantly lower in patients with BD than in controls (P=0.003, OR =0.579), was significantly higher in patients with DM than in those with BD (P=0.0002, OR =1.878). The rs2292910-CC genotypic frequency of the CRY2 gene was significantly higher in patients with BD than in controls (OR of regression =2.203, P=0.01), while the frequency of the AA genotype was significantly lower than in patients with DM (P=0.01). The frequency of rs1972874-G and rs36124720-G haplotype of the PER2 gene was significantly higher in patients with DM than in controls (P=0.01, OR =1.577).

Conclusions

Our study preliminarily suggested that both BD and type 2 DM could be considered as dysrhythmias with different rhythmic genetic backgrounds, which contribute to the early prediction of an individual’s susceptibility to different rhythm disorders and early intervention.

Hibernation with rhythmicity: the circadian clock and hormonal adaptations of the hibernating Asiatic toads (Bufo gargarizans)

Hibernation is one of the fundamental strategies in response to cold environmental temperatures. During hibernation, the endocrine and circadian systems ensure minimal expenditure of energy for survival. The circadian rhythms of key hormones, melatonin (MT), corticosterone (CORT), triiodothyronine (T₃ ), and thyroxine (T₄ ), and the underlying molecular regulatory mechanisms of hibernation have been well determined in mammals but not in ectotherms. Here, a terrestrial hibernating species, Asiatic toad (Bufo gargarizans), was employed to investigate the plasma CORT, MT, T₃ , and T₄ ; and the retina, brain, and liver mRNA expression of the core clock genes, including circadian locomotor output cycles kaput (Clock), brain and muscle ARNT-like 1 (Bmal1), cryptochrome (Cry) 1 and 2, and period (Per) 1 and 2, at 7-time points over a 24-h period under acute cold (1 day at 4°C), and hibernation (45 days at 4°C). Our results showed that the circadian rhythms of the core clock genes were rather unaffected by acute cold exposure in the retina, unlike the brain and liver. In contrast, during hibernation, the liver clock genes displayed significant circadian oscillations, while those in the retina and brain stopped ticking. Furthermore, plasma CORT expressed circadian oscillations in both groups, and T₃ in acute cold exposure group, whereas T₄ and MT did not. Our results reveal that the plasma CORT and the liver sustain rhythmicity when the brain was not, indicating that the liver clock along with the adrenal clock synergistically maintains the metabolic requirements to ensure basic survival in hibernating Asiatic toads.

Iron Metabolism in Pancreatic Beta-Cell Function and Dysfunction

Iron is an essential element involved in a variety of physiological functions. In the pancreatic beta-cells, being part of Fe-S cluster proteins, it is necessary for the correct insulin synthesis and processing. In the mitochondria, as a component of the respiratory chain, it allows the production of ATP and reactive oxygen species (ROS) that trigger beta-cell depolarization and potentiate the calcium-dependent insulin release. Iron cellular content must be finely tuned to ensure the normal supply but also to prevent overloading. Indeed, due to the high reactivity with oxygen and the formation of free radicals, iron excess may cause oxidative damage of cells that are extremely vulnerable to this condition because the normal elevated ROS production and the paucity in antioxidant enzyme activities. The aim of the present review is to provide insights into the mechanisms responsible for iron homeostasis in beta-cells, describing how alteration of these processes has been related to beta-cell damage and failure. Defects in iron-storing or -chaperoning proteins have been detected in diabetic conditions; therefore, the control of iron metabolism in these cells deserves further investigation as a promising target for the development of new disease treatments.

Social communication activates the circadian gene Tctimeless in Tribolium castaneum

Chemical communication via pheromones is an integral component in insect behavior, particularly for mate searching and reproduction. Aggregation pheromones, that attract conspecifics of both sexes, are particularly common and have been identified for hundreds of species. These pheromones are among the most ecologically selective pest suppression agents. In this study, we identified an activating effect of the aggregation pheromone of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenibroidae) on a highly conserved circadian clock gene (Tctimeless). Tribolium castaneum is one of the most damaging cosmopolitan pest of flour and other stored food products. Its male produced aggregation pheromone, 4,8-dimethyldecanal (DMD), attracts both conspecific males and females and is used for pest management via monitoring and mating disruption. The Tctimeless gene is an essential component for daily expression patterns of the circadian clock and plays vital roles in eclosion, egg production, and embryonic development. In this study, we demonstrate that constant exposure to the species-specific aggregation pheromone led to Tctimeless up-regulation and a different pattern of rhythmic locomotive behavior. We propose that changing the well-adapted "alarm clock", using DMD is liable to reduce fitness and can be highly useful for pest management.

Long-Term Effects of Very Low Dose Particle Radiation on Gene Expression in the Heart: Degenerative Disease Risks

Compared to low doses of gamma irradiation (γ-IR), high-charge-and-energy (HZE) particle IR may have different biological response thresholds in cardiac tissue at lower doses, and these effects may be IR type and dose dependent. Three- to four-month-old female CB6F1/Hsd mice were exposed once to one of four different doses of the following types of radiation: γ-IR ¹³⁷Cs (40-160 cGy, 0.662 MeV), ¹⁴Si-IR (4-32 cGy, 260 MeV/n), or ²²Ti-IR (3-26 cGy, 1 GeV/n). At 16 months post-exposure, animals were sacrificed and hearts were harvested and archived as part of the NASA Space Radiation Tissue Sharing Forum. These heart tissue samples were used in our study for RNA isolation and microarray hybridization. Functional annotation of twofold up/down differentially expressed genes (DEGs) and bioinformatics analyses revealed the following: (i) there were no clear lower IR thresholds for HZE- or γ-IR; (ii) there were 12 common DEGs across all 3 IR types; (iii) these 12 overlapping genes predicted various degrees of cardiovascular, pulmonary, and metabolic diseases, cancer, and aging; and (iv) these 12 genes revealed an exclusive non-linear DEG pattern in ¹⁴Si- and ²²Ti-IR-exposed hearts, whereas two-thirds of γ-IR-exposed hearts revealed a linear pattern of DEGs. Thus, our study may provide experimental evidence of excess relative risk (ERR) quantification of low/very low doses of full-body space-type IR-associated degenerative disease development.

Sleep, Cognition and Cortisol in Addison's Disease: A Mechanistic Relationship

Sleep is a critical biological process, essential for cognitive well-being. Neuroscientific literature suggests there are mechanistic relations between sleep disruption and memory deficits, and that varying concentrations of cortisol may play an important role in mediating those relations. Patients with Addison's disease (AD) experience consistent and predictable periods of sub- and supra-physiological cortisol concentrations due to lifelong glucocorticoid replacement therapy, and they frequently report disrupted sleep and impaired memory. These disruptions and impairments may be related to the failure of replacement regimens to restore a normal circadian rhythm of cortisol secretion. Available data provides support for existing theoretical frameworks which postulate that in AD and other neuroendocrine, neurological, or psychiatric disorders, disrupted sleep is an important biological mechanism that underlies, at least partially, the memory impairments that patients frequently report experiencing. Given the literature linking sleep disruption and cognitive impairment in AD, future initiatives should aim to improve patients' cognitive performance (and, indeed, their overall quality of life) by prioritizing and optimizing sleep. This review summarizes the literature on sleep and cognition in AD, and the role that cortisol concentrations play in the relationship between the two.

Transcriptome Analysis of the Cerebellum of Mice Fed a Manganese-Deficient Diet

Manganese (Mn), primarily acquired through diet, is required for brain function and development. Epidemiological studies have found an association between both low and high levels of Mn and impaired neurodevelopment in children. Recent genetic studies have revealed that patients with congenital Mn deficiency display severe psychomotor disability and cerebral and cerebellar atrophy. Although the impact of Mn on gene expression is beginning to be appreciated, Mn-dependent gene expression remains to be explored in vertebrate animals. The goal of this study was to use a mouse model to define the impact of a low-Mn diet on brain metal levels and gene expression. We interrogated gene expression changes in the Mn-deficient mouse brain at the genome-wide scale by RNA-seq analysis of the cerebellum of mice fed low or normal Mn diets. A total of 137 genes were differentially expressed in Mn-deficient cerebellums compared with Mn-adequate cerebellums (Padj < 0.05). Mn-deficient mice displayed downregulation of key pathways involved with "focal adhesion," "neuroactive ligand-receptor interaction," and "cytokine-cytokine receptor interaction" and upregulation of "herpes simplex virus 1 infection," "spliceosome," and "FoxO signaling pathway." Reactome pathway analysis identified upregulation of the splicing-related pathways and transcription-related pathways, as well as downregulation of "metabolism of carbohydrate," and "extracellular matrix organization," and "fatty acid metabolism" reactomes. The recurrent identifications of splicing-related pathways suggest that Mn deficiency leads to upregulation of splicing machineries and downregulation of diverse biological pathways.

Systematic review of melatonin levels in individuals with complete cervical spinal cord injury

Context: Pineal melatonin production is mediated by afferent signaling pathways that navigate through the cervicothoracic spinal cord. Melatonin profiles in individuals with complete cervical spinal cord injury (SCI) have not been systematically reviewed despite this proposed pathway. Objectives: The primary objective was to understand melatonin profiles in individuals with complete cervical SCI, as compared to healthy controls and those with thoracolumbar and incomplete cervical SCI. Secondary objectives were to understand the impact of injury chronicity and melatonin supplementation on melatonin values in adults with complete cervical SCI. Methods: This review (PROSPERO ID: CRD42017073767) searched several databases and gray literature sources from January 1978 to August 2017. Studies were eligible if they evaluated melatonin levels (blood, saliva or urinary metabolite measurements) in adults with complete cervical SCI. 390 studies were screened and 12 studies met final selection criteria. Given the heterogeneity in study designs, a narrative analysis was performed. Results: There is evidence that adults with complete cervical SCI have absent diurnal melatonin rhythms as compared to healthy controls and individuals with thoracolumbar SCI below T3. There is limited evidence comparing levels in individuals with incomplete tetraplegia. There is insufficient evidence describing profiles immediately (<2 weeks) after cervical SCI. Based on a limited number of studies, melatonin supplementation does not appear to improve sleep outcomes in adults with long-standing complete cervical SCI. Conclusions: Future research should explore melatonin levels acutely after cervical SCI and the impact of supplementation on non-sleep outcomes.

Melatonin: an endogenous miraculous indolamine, fights against cancer progression

PURPOSE

Melatonin is an amphipathic indolamine molecule ubiquitously present in all organisms ranging from cyanobacteria to humans. The pineal gland is the site of melatonin synthesis and secretion under the influence of the retinohypothalamic tract. Some extrapineal tissues (skin, lens, gastrointestinal tract, testis, ovary, lymphocytes, and astrocytes) also enable to produce melatonin. Physiologically, melatonin regulates various functions like circadian rhythm, sleep-wake cycle, gonadal activity, redox homeostasis, neuroprotection, immune-modulation, and anticancer effects in the body. Inappropriate melatonin secretion advances the aging process, tumorigenesis, visceral adiposity, etc. METHODS: For the preparation of this review, I had reviewed the literature on the multidimensional activities of melatonin from the NCBI website database PubMed, Springer Nature, Science Direct (Elsevier), Wiley Online ResearchGate, and Google Scholar databases to search relevant articles. Specifically, I focused on the roles and mechanisms of action of melatonin in cancer prevention.

RESULTS

The actions of melatonin are primarily mediated by G-protein coupled MT1 and MT2 receptors; however, several intracellular protein and nuclear receptors can modulate the activity. Normal levels of the melatonin protect the cells from adverse effects including carcinogenesis. Therapeutically, melatonin has chronomedicinal value; it also shows a remarkable anticancer property. The oncostatic action of melatonin is multidimensional, associated with the advancement of apoptosis, the arrest of the cell cycle, inhibition of metastasis, and antioxidant activity.

CONCLUSION

The present review has emphasized the mechanism of the anti-neoplastic activity of melatonin that increases the possibilities of the new approaches in cancer therapy.

Disruption of Circadian Rhythms: A Crucial Factor in the Etiology of Infertility

Infertility represents a growing health problem in industrialized countries. Thus, a greater understanding of the molecular networks involved in this disease could be critical for the development of new therapies. A recent finding revealed that circadian rhythmicity disruption is one of the main causes of poor reproductive outcome. The circadian clock system beats circadian rhythms and modulates several physiological functions such as the sleep-wake cycle, body temperature, heart rate, and hormones secretion, all of which enable the body to function in response to a 24 h cycle. This intricated machinery is driven by specific genes, called “clock genes” that fine-tune body homeostasis. Stress of modern lifestyle can determine changes in hormone secretion, favoring the onset of infertility-related conditions that might reflect disfunctions within the hypothalamic–pituitary–gonadal axis. Consequently, the loss of rhythmicity in the suprachiasmatic nuclei might affect pulsatile sexual hormones release. Herein, we provide an overview of the recent findings, in both animal models and humans, about how fertility is influenced by circadian rhythm. In addition, we explore the complex interaction among hormones, fertility and the circadian clock. A deeper analysis of these interactions might lead to novel insights that could ameliorate the therapeutic management of infertility and related disorders.

Identification and meta-analysis of copy number variation-driven circadian clock genes for colorectal cancer

Both copy number variation (CNV) and circadian clock genes play a critical role in the etiology and pathogenesis of colorectal cancer (CRC); however, a comprehensive analysis of CNV-driven circadian clock genes is urgently required. The present study aimed to investigate the systematic associations between somatic cell CNVs and circadian clock gene expression in patients with CRC. Using somatic CNV, legacy clinical information and gene expression data from The Cancer Genome Atlas, 295 genes that were significantly differentially expressed and with significantly different CNV were obtained, and the expression of the genes, among which 15 were circadian clock genes, was significantly associated with CNV. Further analysis revealed that aryl hydrocarbon receptor nuclear translocator-like 2 (ARNTL2) expression and CNV in these circadian clock genes were significantly associated with survival time in patients with CRC, and the expression of ARNTL2 was also significantly associated with the pathological stage of CRC. Gene set enrichment analysis found that ARNTL2 is enriched for gene sets associated with CRC pathogenesis such as the p53 signaling pathway. These results suggest that ARNTL2 may be a promising prognostic biomarker for patients with CRC, and that circadian clock genes play an important role in CRC through CNV.

The Role of the Molecular Clock in Promoting Skeletal Muscle Growth and Protecting against Sarcopenia

The circadian clock has a critical role in many physiological functions of skeletal muscle and is essential to fully understand the precise underlying mechanisms involved in these complex interactions. The importance of circadian expression for structure, function and metabolism of skeletal muscle is clear when observing the muscle phenotype in models of molecular clock disruption. Presently, the maintenance of circadian rhythms is emerging as an important new factor in human health, with disruptions linked to ageing, as well as to the development of many chronic diseases, including sarcopenia. Therefore, the aim of this review is to present the latest findings demonstrating how circadian rhythms in skeletal muscle are important for maintenance of the cellular physiology, metabolism and function of skeletal muscle. Moreover, we will present the current knowledge about the tissue-specific functions of the molecular clock in skeletal muscle.

Iodine Status in Schoolchildren and Pregnant Women of Lazio, a Central Region of Italy

The inhabitants of Lazio, similarly to those of other Italian regions, have been historically exposed to the detrimental effects of an inadequate intake of iodine. The latter is a micronutrient essential for the biosynthesis of thyroid hormones (TH). Iodine deficiency is responsible for a number of adverse effects on human health known as iodine deficiency disorders (IDD), the most common of which worldwide are goiter and hypothyroidism. In order to reduce IDD, a national salt iodination program was started in Italy in 2005. In this article we reviewed the available data regarding iodine intake in the Lazio population before and after the introduction of the national salt iodination program, in order to evaluate its efficacy and the eventual problem(s) limiting its success. On the whole, the information acquired indicates that, following the introduction of the program, the dietary iodine intake in the Lazio population is improved. There is, however, still much work ahead to ameliorate the iodine prophylaxis in this region. In fact, although a generally adequate iodine intake in school-age children has been observed, there are still areas where a mild iodine insufficiency is present. Moreover, two independent epidemiological surveys on pregnant women evidenced a low urinary iodine concentration with respect to the reference range conceived by the World Health Organization. These findings demonstrate the need for greater attention to the iodine prophylaxis by health care providers (i.e., obstetricians, gynecologists, pediatricians, etc.), and the implementation of effective advertising campaigns aimed at increasing the knowledge and awareness of the favorable effects of iodine supplementation on population health.

New Insights Into the Circadian Rhythm and Its Related Diseases

Circadian rhythms (CR) are a series of endogenous autonomous oscillators generated by the molecular circadian clock which acting on coordinating internal time with the external environment in a 24-h daily cycle. The circadian clock system is a major regulatory factor for nearly all physiological activities and its disorder has severe consequences on human health. CR disruption is a common issue in modern society, and researches about people with jet lag or shift works have revealed that CR disruption can cause cognitive impairment, psychiatric illness, metabolic syndrome, dysplasia, and cancer. In this review, we summarized the synchronizers and the synchronization methods used in experimental research, and introduced CR monitoring and detection methods. Moreover, we evaluated conventional CR databases, and analyzed experiments that characterized the underlying causes of CR disorder. Finally, we further discussed the latest developments in understanding of CR disruption, and how it may be relevant to health and disease. Briefly, this review aimed to synthesize previous studies to aid in future studies of CR and CR-related diseases.

Circadian Clock Genes in Diabetic Kidney Disease (DKD)

PURPOSE OF REVIEW

The purpose of this review is to provide a brief summary about the current state of knowledge regarding the circadian rhythm in the regulation of normal renal function.

RECENT FINDINGS

There is a lack of information regarding how the circadian clock mechanisms may contribute to the development of diabetic kidney disease. We discuss recent findings regarding mechanisms that are established in diabetic kidney disease and are known to be linked to the circadian clock as possible connections between these two areas. Here, we hypothesize various mechanisms that may provide a link between the clock mechanism and kidney disease in diabetes based on available data from humans and rodent models.

Circadian Clock Genes in the Metabolism of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a common disease, which is characterized by the accumulation of triglycerides in the hepatocytes without excess alcohol intake. Circadian rhythms can participate in lipid, glucose, and cholesterol metabolism and are closely related to metabolism seen in this disease. Circadian clock genes can modulate liver lipid metabolism. Desynchrony of circadian rhythms and the influences imparted by external environmental stimuli can increase morbidity. By contrast, synchronizing circadian rhythms can help to alleviate the metabolic disturbance seen in NAFLD. In this review, we have discussed the current research connections that exist between the circadian clock and the metabolism of NAFLD, and we have specifically focused on the key circadian clock genes, Bmal1, Clock, Rev-Erbs, Rors, Pers, Crys, Nocturnin, and DECs.

Disruption of the Pituitary Circadian Clock Induced by Hypothyroidism and Hyperthyroidism: Consequences on Daily Pituitary Hormone Expression Profiles

BACKGROUND

The secretion of pituitary hormones oscillates throughout the 24-hour period, indicating that circadian clock-mediated mechanisms regulate this process in the gland. Additionally, pituitary hormone synthesis has been shown to be altered in hypo- and hyperthyroidism. Although thyroid hormones can modulate the other peripheral clocks, the interaction between thyroid hormone levels and circadian clock gene expression in the anterior pituitary has yet to be elucidated.

METHODS

Male Wistar rats were divided into three groups: control, hypothyroid, and hyperthyroid. Following the experimental procedures, animals were euthanized every three hours over the course of a 24-hour period. The anterior pituitary glands were excised and processed for mRNA expression analysis by quantitative reverse transcriptase polymerase chain reaction. One- and two-way analysis of variance as well as cosinor analysis were used to evaluate the time-of-day-dependent differential expression for each gene in each experimental group and their interactions.

RESULTS

Hyperthyroidism increased the mRNA expression of core clock genes and thyrotrophic embryonic factor (Tef), as well as the mesor and amplitude of brain and muscle Arnt-like protein-1 (Bmal1) and the mesor of nuclear receptor subfamily 1 (Nr1d1) group D member 1, when compared to euthyroid animals. Hypothyroidism disrupted the circadian expression pattern of Bmal1 and period circadian regulator 2 (Per2) and decreased the mesor of Nr1d1 and Tef. Furthermore, it was observed that the pituitary content of Dio2 mRNA was unaltered in hyperthyroidism but substantially elevated in hypothyroidism during the light phase. The upregulated expression was associated with an increased mesor and amplitude, along with an advanced acrophase. The gene expression of all the pituitary hormones was found to be altered in hypo- and hyperthyroidism. Moreover, prolactin (Prl) and luteinizing hormone beta subunit (Lhb) displayed circadian expression patterns in the control group, which were disrupted in both the hypo- and hyperthyroid states.

CONCLUSION

Taken together, the data demonstrate that hypo- and hyperthyroidism alter circadian clock gene expression in the anterior pituitary. This suggests that triiodothyronine plays an important role in the regulation of pituitary gland homeostasis, which could ultimately influence the rhythmic synthesis and/or secretion of all the anterior pituitary hormones.

Bisphenol A Alters Bmal1, Per2, and Rev-Erba mRNA and Requires Bmal1 to Increase Neuropeptide Y Expression in Hypothalamic Neurons

Bisphenol A (BPA), a ubiquitous environmental endocrine disruptor, is considered an obesogen. However, its role in the hypothalamic control of energy balance remains largely unexplored. Because disruption of the circadian clock is tightly associated with metabolic consequences, we explored how BPA affects the components of the molecular circadian clock in the feeding-related neurons of the hypothalamus. In immortalized POMC and NPY/AgRP-expressing hypothalamic cell lines and primary culture, we describe how BPA significantly alters mRNA expression of circadian clock genes Bmal1,Per2, and Rev-Erbα. Furthermore, we use newly generated Bmal1-knockout (KO) hypothalamic cell lines to link the BPA-induced neuropeptide dysregulation to the molecular clock. Specifically, BPA increased Npy, Agrp, and Pomc mRNA expression in wild type hypothalamic cells, whereas the increase in Npy, but not Agrp or Pomc, was abolished in cell lines lacking BMAL1. In line with this increase, BPA led to increased BMAL1 binding to the Npy promotor, potentially increasing Npy transcription. In conclusion, we show that BPA-mediated dysregulation of the circadian molecular clock is linked to the deleterious effects of BPA on neuropeptide expression. Furthermore, we describe hypothalamic Bmal1-KO cell lines to study the role of BMAL1 in hypothalamic responses to metabolic, hormonal, and environmental factors.

An Overview of the Polymorphisms of Circadian Genes Associated With Endocrine Cancer

A major consequence of the world industrialized lifestyle is the increasing period of unnatural light in environments during the day and artificial lighting at night. This major change disrupts endogenous homeostasis with external circadian cues, which has been associated to higher risk of diseases affecting human health, mainly cancer among others. Circadian disruption promotes tumor development and accelerate its fast progression. The dysregulation mechanisms of circadian genes is greatly affected by the genetic variability of these genes. To date, several core circadian genes, also called circadian clock genes, have been identified, comprising the following: ARNTL, CLOCK, CRY1, CRY2, CSNK1E, NPAS2, NR1D1, NR1D2, PER1, PER2, PER3, RORA, and TIMELESS. The polymorphic variants of these circadian genes might contribute to an individual's risk to cancer. In this short review, we focused on clock circadian clock-related genes, major contributors of the susceptibility to endocrine-dependent cancers through affecting circadian clock, most likely affecting hormonal regulation. We examined polymorphisms affecting breast, prostate and ovarian carcinogenesis, in addition to pancreatic and thyroid cancer. Further study of the genetic composition in circadian clock-controlled tumors will be of great importance by establishing the foundation to discover novel genetic biomarkers for cancer prevention, prognosis and target therapies.

Melatonin as a Hormone: New Physiological and Clinical Insights

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

Hypothyroidism and Cognitive Disorders during Development and Adulthood: Implications in the Central Nervous System

Thyroid hormones (THs) play a critical function in fundamental signaling of the body regulating process such as metabolism of glucose and lipids, cell maturation and proliferation, and neurogenesis, to name just a few. THs trigger biological effects both by directly affecting gene expression through the interaction with nuclear receptors (genomic effects) and by activating protein kinases and/or ion channels (short-term effects). For years, a close relationship between the THs hormones and the central nervous system (CNS) has been described, not only for neuronal cells but also for glial development and differentiation. A deficit in thyroid hormones triiodothyronine (T₃) and thyroxine (T₄) is observed in the hypothyroid condition, generated by a iodine deficiency or an autoimmune response of the body. In the hypothyroid condition, several cellular deregulation and alterations have been described in dendrite spine morphology, cell migration and proliferation, and impaired synaptic transmission in the hippocampus, among others. The aim of this review is to describe the role of the thyroid hormones with focus in brain function and neurodegenerative disorders.