Associations of polymorphisms in circadian genes with abdominal obesity in Chinese adult population

Circadian clock gene polymorphisms implicated in human pathologies

Circadian rhythms, ~24 h cycles of physiological and behavioral processes, can be synchronized by external signals (e.g., light) and persist even in their absence. Consequently, dysregulation of circadian rhythms adversely affects the well-being of the organism. This timekeeping system is generated and sustained by a genetically encoded endogenous mechanism composed of interlocking transcriptional/translational feedback loops that generate rhythmic expression of core clock genes. Genome-wide association studies (GWAS) and forward genetic studies show that SNPs in clock genes influence gene regulation and correlate with the risk of developing various conditions. We discuss genetic variations in core clock genes that are associated with various phenotypes, their implications for human health, and stress the need for thorough studies in this domain of circadian regulation.

The interaction between CRY1 Polymorphism and Alternative Healthy Eating Index (AHEI) on cardiovascular risk factors in overweight women and women with obesity: a cross-sectional study

BACKGROUND

According to some studies, diet can be interaction with CRY1 polymorphism and may be related to obesity and the risk of cardiovascular diseases (CVD). So, this study examined the interaction between CRY1 polymorphism and AHEI on cardiovascular risk factors in overweight women and women with obesity.

METHODS

This cross-sectional study was performed on 377 Iranian women with overweight and obesity aged 18-48(BMI ≥ 25 kg/m2). Dietary intake was evaluated by the use of a food frequency questionnaire (FFQ) with 147 items. The AHEI was calculated based on previous studies. Anthropometric and biochemical measurements were assessed and the bioelectrical impedance analysis method was used for body analysis. The rs2287161 was genotyped by the restriction fragment length polymorphism (PCR-RFLP) method. Objects were divided into three groups based on rs2287161 genotypes.

RESULTS

Our findings determined that the prevalence of the C allele was 51.9% and the G allele was 48.0%. The mean age and BMI were 36.6 ± 9.1years and 31 ± 4 kg/m2 respectively. After controlling for confounders (BMI, age, total energy intake, and physical activity), this study demonstrated that there was a significant interaction between CC genotype and adherence to AHEI on odds of hyper LDL (OR = 1.94, 95% CI = 1.24-3.05, P for interaction = 0.004), hypertension (OR = 1.80, 95% CI = 1.11-2.93, P for interaction = 0.01) and hyperglycemia (OR = 1.56, 95% CI = 0.98-2.47, P for interaction = 0.05).

CONCLUSIONS

This study indicated that adherence to AHEI can reduce the odds of hyper LDL, hypertension, and hyperglycemia in the CC genotype of rs2287161.

Positive Interaction Between CG, CC Genotypes of Cryptochrome Circadian Clocks 1, and Energy-Adjusted Dietary Inflammatory Index on High Sensitivity C-Reactive Protein Level in Women With Central Obesity

Creating a complex balance between dietary composition, circadian rhythm, and the hemostasis control of energy is important for managing diseases. Therefore, we aimed to determine the interaction between cryptochrome circadian clocks 1 polymorphism and energy-adjusted dietary inflammatory index (E-DII) on high-sensitivity C-reactive protein in women with central obesity. This cross-sectional study recruited 220 Iranian women aged 18-45 with central obesity. The 147-item semi-quantitative food frequency questionnaire was used to assess the dietary intakes, and the E-DII score was calculated. Anthropometric and biochemical measurements were determined. By polymerase chain response-restricted length polymorphism method, cryptochrome circadian clocks 1 polymorphism was assigned. Participants were categorized into three groups based on the E-DII score, then categorized according to cryptochrome circadian clocks 1 genotypes. The mean and standard deviation of age, BMI, and high-sensitivity C-reactive protein (hs-CRP) were 35.61 ± 9.57 years, 30.97 ± 4.16 kg/m², and 4.82 ± 5.16 mg/dL, respectively. The interaction of the CG genotype and E-DII score had a significant association with higher hs-CRP level compared to GG genotype as the reference group (β, 1.19; 95% CI, 0.11-2.27; p value, 0.03). There was a marginally significant association between the interaction of the CC genotype and the E-DII score with higher hs-CRP level compared to the GG genotype as the reference group (β, 0.85; 95% CI, -0.15 to 1.86; p value, 0.05). There is probably positive interaction between CG, CC genotypes of cryptochrome circadian clocks 1, and E-DII score on the high-sensitivity C-reactive protein level in women with central obesity.

Chrononutrition-When We Eat Is of the Essence in Tackling Obesity

Obesity is a chronic and relapsing public health problem with an extensive list of associated comorbidities. The worldwide prevalence of obesity has nearly tripled over the last five decades and continues to pose a serious threat to wider society and the wellbeing of future generations. The pathogenesis of obesity is complex but diet plays a key role in the onset and progression of the disease. The human diet has changed drastically across the globe, with an estimate that approximately 72% of the calories consumed today come from foods that were not part of our ancestral diets and are not compatible with our metabolism. Additionally, multiple nutrient-independent factors, e.g., cost, accessibility, behaviours, culture, education, work commitments, knowledge and societal set-up, influence our food choices and eating patterns. Much research has been focused on 'what to eat' or 'how much to eat' to reduce the obesity burden, but increasingly evidence indicates that 'when to eat' is fundamental to human metabolism. Aligning feeding patterns to the 24-h circadian clock that regulates a wide range of physiological and behavioural processes has multiple health-promoting effects with anti-obesity being a major part. This article explores the current understanding of the interactions between the body clocks, bioactive dietary components and the less appreciated role of meal timings in energy homeostasis and obesity.

Sex-specific genetic association of brain and muscle Arnt-like protein-1 (BMAL1) and obesity in Chinese youth

BACKGROUND

The circadian clock gene brain and muscle Arnt-like protein-1 (BMAL1) regulates energy metabolism, adipocyte proliferation and differentiation, glucose metabolism, and other functions. This study aimed to examine the association of potential polymorphisms in BMAL1 with obesity among Chinese youth.

METHODS

A total of 2973 participants were included in this study. According to the body mass index obesity standard of China, 208 subjects were defined as experiencing general obesity. According to the waist-to-hip ratio obesity standard, 335 participants were defined as experiencing central obesity. Four single nucleotide polymorphisms (SNPs) (rs9633835, rs6486121, rs7107287, and rs12364562) were genotyped using TaqMan probe techniques.

RESULTS

There was no significant difference in the either genotypic or allelic frequencies between the non-general and general obesity groups, while a positive association was observed between BMAL1 rs6486121 variant and central obesity risk (CC＋CT vs. TT: OR:2.139, 95% CI:1.164-3.930; P = 0.014) after adjusting for covariates. Stratification analyses revealed significant associations with central obesity risk for rs6486121 polymorphism in women according to the additive model (CC vs. CT vs. TT: OR：1.409; 95 % CI: 1.029-1.930; P = 0.032). Haplotype analysis showed that only paired haplotypes, including rs9633835G with rs6486121T, had a significant effect on central obesity with OR (95%CI) was 1.035 (1.011-1.060) and P = 0.004.

CONCLUSION

our findings suggest that BMAL1 polymorphisms are significantly associated with central obesity and sex-specific genetic effects on BMAL1-mediated genetic susceptibility to obesity.

Interaction of cry1 gene polymorphisms and dominant food patterns on obesity: A cross-sectional study

Background:

Evidence suggests that there is some relationship between circadian clock gene variants and obesity. However, there are few examinations supporting this observation in human subjects. This study was aimed to investigate the interaction between Cry1 circadian gene polymorphism and major dietary patterns on obesity measurements.

Methods:

Healthy overweight and obese women aged 18–53 years old were recruited from health centers in Tehran, Iran by a multistage cluster random sampling method (n = 377). Major dietary patterns were elicited after assessing the intake of 16 food groups using a valid and reliable 147-item food frequency questionnaire (FFQ). Anthropometric measurements were performed for each and every participant. Body composition was analyzed using bioelectrical impedance analysis (BIA). Socio-demographic and physical activity data were also collected by a validated Farsi demographic questionnaire and the international physical activity questionnaire (IPAQ). The Cry1 rs2287161 polymorphism were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Generalized linear models were used for interaction analysis.

Results:

Two major dietary patterns, including healthy and unhealthy dietary pattern (HDP and UDP, respectively) were determined using factor analysis. Our study showed a significant higher weight (P = 0.003), body mass index (BMI) (P = 0.042), hip circumference (P = 0.052), and body fat mass (P = 0.028) in carriers of C allele compared with G allele. Moreover, a significant gene-diet interaction was observed between being a carrier of C allele and BMI (P = 0.099 for CC genotype; P = 0.1 for CG genotype) and fat mass (P = 0.1 for CG genotype).

Conclusions:

The current study suggests a significant interaction of Cry1 rs2287161 gene polymorphisms in people following a healthy dietary pattern on BMI and fat mass among carriers of C allele compared to carriers of G allele.

The Association between Circadian Clock Gene Polymorphisms and Metabolic Syndrome: A Systematic Review and Meta-Analysis

Metabolic syndrome (MetS) is a combination of cardiovascular risk factors associated with type 2 diabetes, obesity, and cardiovascular diseases. The circadian clock gene polymorphisms are very likely to participate in metabolic syndrome genesis and development. However, research findings of the association between circadian rhythm gene polymorphisms and MetS and its comorbidities are not consistent. In this study, a review of the association of circadian clock gene polymorphisms with overall MetS risk was performed. In addition, a meta-analysis was performed to clarify the association between circadian clock gene polymorphisms and MetS susceptibility based on available data. The PubMed and Scopus databases were searched for studies reporting the association between circadian rhythm gene polymorphisms (ARNTL, BMAL1, CLOCK, CRY, PER, NPAS2, REV-ERBα, REV-ERBβ, and RORα) and MetS, and its comorbidities diabetes, obesity, and hypertension. Thirteen independent studies were analyzed with 17,381 subjects in total. The results revealed that the BMAL1 rs7950226 polymorphism was associated with an increased risk of MetS in the overall population. In contrast, the CLOCK rs1801260 and rs6850524 polymorphisms were not associated with MetS. This study suggests that some circadian rhythm gene polymorphisms might be associated with MetS in different populations and potentially used as predictive biomarkers for MetS.

Every Night and Every Morn: Effect of Variation in CLOCK Gene on Depression Depends on Exposure to Early and Recent Stress

The role of circadian dysregulation is increasingly acknowledged in the background of depressive symptoms, and is also a promising treatment target. Similarly, stress shows a complex relationship with the circadian system. The CLOCK gene, encoding a key element in circadian regulation has been implicated in previous candidate variant studies in depression with contradictory findings, and only a few such studies considered the interacting effects of stress. We investigated the effect of CLOCK variation with a linkage-disequilibrium-based clumping method, in interaction with childhood adversities and recent negative life events, on two phenotypes of depression, lifetime depression and current depressive symptoms in a general population sample. Methods: Participants in NewMood study completed questionnaires assessing childhood adversities and recent negative life events, the Brief Symptom Inventory to assess current depressive symptoms, provided data on lifetime depression, and were genotyped for 1054 SNPs in the CLOCK gene, 370 of which survived quality control and were entered into linear and logistic regression models with current depressive symptoms and lifetime depression as the outcome variable, and childhood adversities or recent life events as interaction variables followed by a linkage disequilibrium-based clumping process to identify clumps of SNPs with a significant main or interaction effect. Results: No significant clumps with a main effect were found. In interaction with recent life events a significant clump containing 94 SNPs with top SNP rs6825994 for dominant and rs6850524 for additive models on current depression was identified, while in interaction with childhood adversities on current depressive symptoms, two clumps, both containing 9 SNPs were found with top SNPs rs6828454 and rs711533. Conclusion: Our findings suggest that CLOCK contributes to depressive symptoms, but via mediating the effects of early adversities and recent stressors. Given the increasing burden on circadian rhythmicity in the modern lifestyle and our expanding insight into the contribution of circadian disruption in depression especially as a possible mediator of stress, our results may pave the way for identifying those who would be at an increased risk for depressogenic effects of circadian dysregulation in association with stress as well as new molecular targets for intervention in stress-related psychopathologies in mood disorders.

Prevalence of abdominal obesity and its association with cardiovascular risk among the adult population in Burkina Faso: findings from a nationwide cross-sectional study

OBJECTIVE

The objective of this study is to determine the prevalence of abdominal obesity, its predictors and its association with cardiovascular risk among adults in Burkina Faso.

DESIGN

We performed a secondary analysis of data from a national cross-sectional study, using WHO STEPwise approach.

SETTING

The study was conducted in Burkina Faso, in all the 13 regions of the country.

PARTICIPANTS

Our study involved 4308 adults of both sexes, aged between 25 and 64 years.

PRIMARY AND SECONDARY OUTCOMES

Our primary outcome was abdominal obesity, which was defined using a cut-off point of waist circumference (WC) of ≥94 cm for men and ≥80 cm for women. The secondary outcome was very high WC (≥102 cm for men and ≥88 cm for women) (for whom weight management is required).

RESULTS

The mean age of participants was 38.5±11.1 years. The age-standardised prevalence of abdominal obesity was 22.5% (95% CI 21.3% to 23.7%). This prevalence was 35.9% (95% CI 33.9% to 37.9%) among women and 5.2% (95% CI 4.3% to 6.2%) among men. In urban areas, the age-standardised prevalence of abdominal obesity was 42.8% (95% CI 39.9% to 45.7%) and 17.0% (95% CI 15.7% to 18.2%) in rural areas. The age-standardised prevalence of very high WC was 10.2% (95% CI 9.3% to 11.1%). The main predictors of abdominal obesity were being female, increased age, married status, high level of education and living in urban areas. Abdominal obesity was also significantly associated with high blood pressure (adjusted prevalence ratio (aPR): 1.30; 95% CI 1.14 to 1.47) and hypercholesterolaemia (aPR: 1.52; 95% CI 1.18 to 1.94). According to the combination matrix between body mass index and WC, 14.6% of the adult population in Burkina Faso had an increased cardiometabolic risk.

CONCLUSION

Our study showed a high prevalence of abdominal obesity and a high proportion of adults who require weight management strategies to prevent cardiometabolic complications. Strategies to reduce the burden of abdominal obesity and very high WC should be considered by Burkina Faso's policy-makers.

Common genetic variation in circadian clock genes are associated with cardiovascular risk factors in an African American and Hispanic/Latino cohort

Misalignment of the internal circadian time with external physical time due to environmental factors or due to genetic variantion in circadian clock genes has been associated with increased incidence of cardiovascular risk factors. Common genetic variation in circadian genes in the United States have been identified predominantly in European ancestry individuals. We therefore examined the association between circadian clock single nucleotide polymorphisms (SNPs) in Clock, Cry1, Cry2, Bmal1 and Per3 genes and cardiovascular risk factors in African Americans and Hispanic/Latinos. We analyzed 17 candidate circadian SNPs in 1,166 subjects who self-identified as African-American or Hispanic/Latino and were enrolled in the UIC Cohort of Patients, Family and Friends. We found significant differences in the minor allele frequencies between African American and Hispanic/Latino subjects. Our analyses also established ethnic-specific SNPs that are associated with cardiovascular risk factors. In Hispanic/Latinos, the rs6850524 in Clock was associated with increased risk for hypertension, meanwhile rs12649507, rs4864546, and rs4864548 reduced the risk, also rs8192440 (Cry1) reduced the risk for type 2 diabetes. In African Americans, the Clock rs1801260 and rs6850524 were negatively associated with the presence of obesity; Bmal1 rs11022775 reduced the risk for dyslipidemia; and the Cry2 rs2292912 increased the risk for dyslipidemia and diabetes. Genetic variations in candidate circadian-clock genes are associated with risk factors for cardiovascular disease in African-Americans and Hispanic/Latinos. Our findings may help to improve cardiovascular risk assessment as well as better understand how circadian misalignment impacts cardiovascular risk in diverse populations.

Correlation between circadian rhythm related genes, type 2 diabetes, and cancer: Insights from metanalysis of transcriptomics data

Clock genes work as an auto-regulated transcription-translational loop of circadian genes that drives the circadian rhythms in each cell and they are essential to physiological requests. Since metabolism is a dynamic process, it involves several physiological variables that circadian cycling. The clock genes alterations can affect multiple systems concomitantly, because they constitute the promoter factors for relevant metabolic pathways. Considering the intertwined structure of signaling, regulatory, and metabolic processes within a cell, we employed a genome-scale biomolecular network. Accordingly, a meta-analysis of diabetic-associated transcriptomic datasets was performed, and the core information on differentially expressed genes (DEGs) was obtained by statistical analyses. In the current study, meta-analysis was performed on type 2 diabetes, circadian rhythm-related genes, and breast, bladder, liver, pancreas, colon and rectum cancer-associated transcriptome data using the integration of gene expression profiles with genome-scale biomolecular networks in diabetes samples. First, we detected downregulated and upregulated DEGs in mouse cortex and hypothalamus samples of mice with sleep deprivation. In summary, upregulated genes active genes associated with oxidative phosphorylation, cancer and diabetes, mainly in hypothalamus specimens. In cortex, we observed mainly downregulation of immune system. DEGs were combined with 214 circadian rhythm related genes to type 2 DM and cancer samples. We observed that several common genes deregulated in both diseases. Klf10, Ntkr3, Igf1, Usp2, Ezh2 were both downregulated in type 2 DM and cancer samples, while Arntl2 and Agrp were upregulated. It seems that the changes in mRNA are contributing to the phenotypic changes in type 2 DM, resulting in phenotypic changes associated with the malignant transformation. Taking those genes to perform a survival analysis, we found only Igf1, Usp2 and Arntl2 genes associated with patient outcomes. While Igf1 and Usp2 downregulation had a negative impact, Arntl2 upregulation was associated with poor survival both in BLCA and BRCA cancer samples. Our data stimulate efforts in news studies to achieve the experimental and clinical validation about these biomolecules.

The Independent Role of Body Mass Index (BMI) and Severity of Depressive Symptoms on Biological Changes of Women Affected by Overweight/Obesity

Background: Both obesity and depression are medical conditions associated with severe disability and biological abnormalities. Our aim was to study associations between Body Mass Index (BMI), depression and biological changes in women affected by overweight or obesity. Methods: Depressive symptoms were evaluated by the Beck Depression Inventory II (BDI-II) questionnaire in 200 women affected by overweight/obesity (mean age of the sample 52.7 ± 12.9 years, BMI 33.8 ± 5.5 kg/m²). A blood sample was obtained for evaluation of biochemical (oxytocin and vitamin D), inflammatory and epigenetic (methylation of clock genes) parameters. Multivariable linear regression models were used to study the association between BMI or severity of depressive symptoms (BDI-II scores) with different biomarkers. Results: BMI was found to be associated with severity of depressive symptoms (p = 0.050). Severity of obesity resulted to be associated with lower plasma levels of oxytocin (p = 0.053), vitamin D deficiency (p = 0.006) and higher plasma levels of IFN-γ (p = 0.004), IL-6 (p = 0.013), IL-7 (p = 0.013), TNF-alpha (p = 0.036) and chemokine ligand 3 (CCL3) (p = 0.013, R² = 0.03). Severity of depression was significantly associated with more methylation of clock genes CRY1 (p = 0.034, R² = 0.16) and CRY2 (p = 0.019, R² = 0.47). More severe depression together with higher levels of IL-8 strongly predicted lower methylation of CLOCK gene (p = 0.009); Conclusions: Different biological abnormalities have been found to be independently associated with BMI and severity of depressive symptoms in women affected by overweight/obesity. The complex interplay between overweight, depression and biological changes will have to be better clarified by future studies.

Visceral adiposity and expression of clock genes in peripheral blood mononuclear cells: A pilot study

Increasing evidence suggests a close interrelationship between disrupted circadian rhythms and obesity and metabolic disturbances. In particular, abdominal obesity, which contributes to the pathogenesis of metabolic disease, is associated with disrupted clock gene expression. However, little is known about the relationship between clock gene expression and accurate computed tomography (CT)-based measurements of visceral adiposity. Therefore, we examined the relationship between expression of clock genes in peripheral blood mononuclear cells (PBMCs) with visceral and subcutaneous adiposity in 75 healthy overweight or obese individuals. PBMCs were obtained from blood samples collected at 8 AM, and gene expression was analyzed by real-time reverse transcription polymerase chain reaction. Visceral and subcutaneous adiposity were measured by CT. Our results showed that visceral fat area was significantly positively correlated with BMAL1 and CRY1 mRNA levels and significantly negatively correlated with CLOCK, PER2, PER3 and CRY2 mRNA levels. In contrast, subcutaneous fat area was not correlated with the expression of any of the clock genes analyzed. After adjusting for multiple variables, visceral fat area was significantly associated with the expression of BMAL1, PER2 and CRY1. Taken together, our results indicate that visceral adiposity, but not subcutaneous adiposity, correlates with expression of clock genes in PBMCs.

Evidences of Polymorphism Associated with Circadian System and Risk of Pathologies: A Review of the Literature

The circadian system is a supraphysiological system that modulates different biological functions such as metabolism, sleep-wake, cellular proliferation, and body temperature. Different chronodisruptors have been identified, such as shift work, feeding time, long days, and stress. The environmental changes and our modern lifestyle can alter the circadian system and increase the risk of developing pathologies such as cancer, preeclampsia, diabetes, and mood disorder. This system is organized by transcriptional/tranductional feedback loops of clock genes Clock, Bmal1, Per1-3, and Cry1-2. How molecular components of the clock are able to influence the development of diseases and their risk relation with genetic components of polymorphism of clock genes is unknown. This research describes different genetic variations in the population and how these are associated with risk of cancer, metabolic diseases such as diabetes, obesity, and dyslipidemias, and also mood disorders such as depression, bipolar disease, excessive alcohol intake, and infertility. Finally, these findings will need to be implemented and evaluated at the level of genetic interaction and how the environment factors trigger the expression of these pathologies will be examined.