FTO Genotype, Physical Activity, and Coronary Heart Disease Risk in Swedish Men and Women

Cold atmospheric plasma control metabolic syndromes via targeting fat mass and obesity-associated protein

Both obesity and metabolic disorders are global medical problems. Driven by prolonged inflammation, obesity increases the risk of developing metabolic syndromes such as fatty liver, diabetes, cardiovascular diseases and cancers. The fat mass and obesity-associated protein (FTO) is an m6A demethylase, elevated activity of which is known to promote the pathogenesis of many metabolic disorders, leading to the establishment of various FTO inhibitors. By combing through intrinsic connections among obesity and the four primary metabolic problems, we attribute their shared pathological cause to prolonged inflammation. By reviewing the roles of FTO in promoting these disorders and the current status of existing FTO inhibitors in treating these syndromes, we underpinned the paramount potential of resolving these clinical issues by targeting FTO and the urgent need of establishing novel FTO inhibitors with maximized efficacy and minimized side effect. Cold atmospheric plasma (CAP) is the fourth state of matter with demonstrated efficacy in treating various diseases associated with chronic inflammation. By introducing the medical characteristics of CAP, we proposed it as a possible solution to unresolved issues of current FTO inhibitors given its anti-inflammation feature and demonstrated clinical safety. We also emphasized the need of intensive investigations in exploring the feasibility of using CAP in treating obesity and associated metabolic syndromes that might function through targeting FTO.

FTO rs1121980 polymorphism contributes to coronary artery disease susceptibility in a Chinese Han population

BACKGROUND

The fat mass and obesity-associated protein (FTO) has been showed to be involved in the pathogenesis and progression of coronary artery disease (CAD). However, the effects of FTO variants on CAD risk remain poorly understood. We herein genotyped three SNPs (rs1121980, rs72803657, and rs4783818) in FTO to investigate the influence of FTO polymorphisms on individual susceptibility to CAD.

METHODS

Genotyping for the three SNPs (rs1121980, rs72803657, and rs4783818) was conducted in a cohort of 712 CAD cases with 349 myocardial infarction (MI) cases and 701 control participants, utilizing the polymerase chain reaction-ligation detection reaction (PCR-LDR) technique. The associations of these SNPs with CAD were analyzed using multivariate logistic regression, and the associations with lipid profiles were assessed by the Kruskal-Wallis or Wilcoxon-Mann-Whitney tests.

RESULTS

The A allele (OR = 1.26, 95% CI = 1.01-1.57, and P = 0.044) and the AA genotype (OR = 3.13, 95% CI = 1.53-6.38, and P = 0.002) of FTO rs1121980 were significantly associated with an elevated risk of CAD. Similarly, the A allele (OR = 1.54, 95% CI = 1.18-2.02, and P = 0.002) and the AA genotype (OR = 5.61, 95% CI = 2.57-12.27, and P < 0.001) of rs1121980 exhibited increased MI risk. This SNP also showed significant associations under recessive genetic models for both CAD and MI (OR = 3.09, 95% CI = 1.52-6.27, P = 0.002 for CAD; OR = 5.40, 95% CI = 2.49-11.71, P < 0.001 for MI). However, the other two SNPs did not show significant associations with CAD or MI risks under any genetic model tested. Stratified analyses indicated a more pronounced association of the A allele with increased CAD/MI risk among younger participants, non-smokers, and non-drinkers. Interestingly, A allele carriers in younger subjects exhibited higher triglyceride (TG) levels and lower high-density lipoprotein cholesterol (HDL-C) levels compared to non-carriers (P < 0.05).

CONCLUSIONS

Our data provides the first evidence that the FTO rs1121980 polymorphism is associated with an increased risk of CAD in the Chinese population. This association is more significant in younger subjects, likely due to the elevated TG levels and reduced HDL-C levels.

Screening of key genes related to M6A methylation in patients with heart failure

OBJECTIVE

This study aims to identify m6A methylation-related and immune cell-related key genes with diagnostic potential for heart failure (HF) by leveraging various bioinformatics techniques.

METHODS

The GSE116250 and GSE141910 datasets were sourced from the Gene Expression Omnibus (GEO) database. Correlation analysis was conducted between differentially expressed genes (DEGs) in HF and control groups, alongside differential m6A regulatory factors, to identify m6A-related DEGs (m6A-DEGs). Subsequently, candidate genes were narrowed down by intersecting key module genes derived from weighted gene co-expression network analysis (WGCNA) with m6A-DEGs. Key genes were then identified through the Least Absolute Shrinkage and Selection Operator (LASSO) analysis. Correlation analyses between key genes and differentially expressed immune cells were performed, followed by the validation of key gene expression levels in public datasets. To ensure clinical applicability, five pairs of blood samples were collected for quantitative real-time fluorescence PCR (qRT-PCR) validation.

RESULTS

A total of 93 m6A-DEGs were identified (|COR| > 0.6, P < 0.05), and five key genes (LACTB2, NAMPT, SCAMP5, HBA1, and PRKAR2A) were selected for further analysis. Correlation analysis revealed that differential immune cells were negatively associated with the expression of LACTB2, NAMPT, and PRKAR2A (P < 0.05), while positively correlated with SCAMP5 and HBA1 (P < 0.05). Subsequent expression validation confirmed significant differences in key gene expression between the HF and control groups, with consistent expression trends observed across both training and validation sets. The expression trends of LACTB2, PRKAR2A, and HBA1 in blood samples from the qRT-PCR assay aligned with the results derived from public databases.

CONCLUSION

This study successfully identified five m6A methylation-related key genes with diagnostic significance, providing a theoretical foundation for further exploration of m6A methylation's molecular mechanisms in HF.

Hypoxia-induced downregulation of RNA m6A protein machinery in the naked mole-rat heart

Naked mole-rats, Heterocephalus glaber, are champion hypoxia-tolerant rodents that live under low oxygen conditions in their subterranean burrows. Detrimental effects of low oxygen can be mitigated through metabolic rate depression (MRD), metabolic reorganization, and global downregulation of nonessential cellular processes. Recent research has progressively implicated epigenetic modifications - rapid, reversible changes to gene expression that do not alter the DNA sequence itself - as major players in implementing and maintaining MRD. N6-adenosine (m6A) methylation is the most prevalent mammalian RNA modification and is responsible for pre-mRNA processing and mRNA export from the nucleus. Hence, m6A -mediated conformational changes alter the cellular fate of transcripts. The present study investigated the role of m6A RNA methylation responses to 24 h of hypoxia exposure in H. glaber cardiac tissue. Total protein levels of m6A writers/readers/erasers, m6A demethylase activity, and total m6A quantification were measured under normoxic vs. hypoxic conditions in H. glaber heart. While there was no change in either demethylase activity or total m6A content, many proteins of the m6A pathway were downregulated during hypoxia. Overall, m6A may not be a signature hypoxia-responsive characteristic in H. glaber heart, but downregulation of the protein machinery involved in m6A cycling points to an alternate biological involvement. Further research will explore other forms of RNA modifications and other epigenetic mechanisms to determine the controls on hypoxia endurance in this subterranean mammal.

Fat Mass and Obesity-Related (FTO) Gene Variant Is a Predictor of CVD in T2DM Patients

Background: The role of the common FTO gene variant rs9939609 in obesity has been well established, and the FTO gene has a strong association with T2DM. Objective: To investigate the association of FTO gene variant rs9939609 with obesity-related parameters in T2DM and CVD patients. Materials and Methods: In this cross-sectional study, 280 subjects of either sex aged 45.10 ± 9.6 years were randomly divided into four groups, that is, T2DM, T2DM with CVD, nondiabetic with CVD disease, and normal control. These samples were genotyped by ARMS-PCR. The FTO gene association with obesity-related parameters in T2DM and CVD patients was analyzed by SPSS 22. Results: The TT genotype was the most common genotype (46.80%) in our study groups. The minor allele frequency (MAF) was significantly higher in T2DM patients (0.39 vs. 0.28), T2DM patients with CVD (0.43 vs. 0.28), and nondiabetic patients with CVD (0.35 vs. 0.28) as compared to control with p < 0.005. Carriers of the AA genotype of the FTO gene rs9939609 were significantly associated with increased BMI, WC, HbA1C, SBP, DBP, and TGs and lowered HDL cholesterol as compared to the TA and TT genotypes in T2DM and CVD patients with p < 0.005. The FTO gene variant rs9939609 showed a significant association with T2DM and CVD. The AA genotype odds ratio (OR) in T2DM was 1.48 (1.06-2.32), p = 0.006, and in CVD, it was 1.56 (1.04-2.4), p = 0.003. Conclusion: The FTO gene variant rs9939609 has a strong association with T2DM and CVD. The AA genotype of FTO gene variants rs9939609 showed a strong association with most of the risk factors of CVD and T2DM.

Sex-based differences in short- and longer-term diet-induced metabolic heart disease

Sex-based differences in the development of obesity-induced cardiometabolic dysfunction are well documented, however, the specific mechanisms are not completely understood. Obesity has been linked to dysregulation of the epitranscriptome, but the role of N6-methyladenosine (m6A) RNA methylation has not been investigated in relation to the sex differences during obesity-induced cardiac dysfunction. In the current study, male and female C57BL/6J mice were subjected to short- and long-term high-fat/high-sucrose (HFHS) diet to induce obesogenic stress. Cardiac echocardiography showed males developed systolic and diastolic dysfunction after 4 mo of diet, but females maintained normal cardiac function despite both sexes being metabolically dysfunctional. Cardiac m6A machinery gene expression was differentially regulated by duration of HFHS diet in male, but not female mice, and left ventricular ejection fraction correlated with RNA machinery gene levels in a sex- and age-dependent manner. RNA-sequencing of cardiac transcriptome revealed that females, but not males may undergo protective cardiac remodeling early in the course of obesogenic stress. Taken together, our study demonstrates for the first time that cardiac RNA methylation machinery genes are regulated early during obesogenic stress in a sex-dependent manner and may play a role in the sex differences observed in cardiometabolic dysfunction.NEW & NOTEWORTHY Sex differences in obesity-associated cardiomyopathy are well documented but incompletely understood. We show for the first time that RNA methylation machinery genes may be regulated in response to obesogenic diet in a sex- and age-dependent manner and levels may correspond to cardiac systolic function. Our cardiac RNA-seq analysis suggests female, but not male mice may be protected from cardiac dysfunction by a protective cardiac remodeling response early during obesogenic stress.

Identification of 6-methyladenosine sites using novel feature encoding methods and ensemble models

N6-methyladenosine (6 mA) is the most common internal modification in eukaryotic mRNA. Mass spectrometry and site-directed mutagenesis, two of the most common conventional approaches, have been shown to be laborious and challenging. In recent years, there has been a rising interest in analyzing RNA sequences to systematically investigate mutated locations. Using novel methods for feature development, the current work aimed to identify 6 mA locations in RNA sequences. Following the generation of these novel features, they were used to train an ensemble of models using methods such as stacking, boosting, and bagging. The trained ensemble models were assessed using an independent test set and k-fold cross validation. When compared to baseline predictors, the suggested model performed better and showed improved ratings across the board for key measures of accuracy.

Studies on the fat mass and obesity-associated (FTO) gene and its impact on obesity-associated diseases

Obesity has become a major health crisis in the past ∼50 years. The fat mass and obesity-associated (FTO) gene, identified by genome-wide association studies (GWAS), was first reported to be positively associated with obesity in humans. Mice with more copies of the FTO gene were observed to be obese, while loss of the gene in mice was found to protect from obesity. Later, FTO was found to encode an m6A RNA demethylase and has a profound effect on many biological and metabolic processes. In this review, we first summarize recent studies that demonstrate the critical roles and regulatory mechanisms of FTO in obesity and metabolic disease. Second, we discuss the ongoing debates concerning the association between FTO polymorphisms and obesity. Third, since several small molecule drugs and micronutrients have been found to regulate metabolic homeostasis through controlling the expression or activity of FTO, we highlight the broad potential of targeting FTO for obesity treatment. Improving our understanding of FTO and the underlying mechanisms may provide new approaches for treating obesity and metabolic diseases.

Precision Nutrition and Cardiovascular Disease Risk Reduction: the Promise of High-Density Lipoproteins

PURPOSE OF REVIEW

Emerging evidence supports the promise of precision nutritional approaches for cardiovascular disease (CVD) prevention. Here, we discuss current findings from precision nutrition trials and studies reporting substantial inter-individual variability in responses to diets and dietary components relevant to CVD outcomes. We highlight examples where early precision nutrition research already points to actionable intervention targets tailored to an individual's biology and lifestyle. Finally, we make the case for high-density lipoproteins (HDL) as a compelling next generation target for precision nutrition aimed at CVD prevention. HDL possesses complex structural features including diverse protein components, lipids, size distribution, extensive glycosylation, and interacts with the gut microbiome, all of which influence HDL's anti-inflammatory, antioxidant, and cholesterol efflux properties. Elucidating the nuances of HDL structure and function at an individual level may unlock personalized dietary and lifestyle strategies to optimize HDL-mediated atheroprotection and reduce CVD risk.

RECENT FINDINGS

Recent human studies have demonstrated that HDL particles are key players in the reduction of CVD risk. Our review highlights the role of HDL and the importance of personalized therapeutic approaches to improve their potential for reducing CVD risk. Factors such as diet, genetics, glycosylation, and gut microbiome interactions can modulate HDL structure and function at the individual level. We emphasize that fractionating HDL into size-based subclasses and measuring particle concentration are necessary to understand HDL biology and for developing the next generation of diagnostics and biomarkers. These discoveries underscore the need to move beyond a one-size-fits-all approach to HDL management. Precision nutrition strategies that account for personalized metabolic, genetic, and lifestyle data hold promise for optimizing HDL therapies and function to mitigate CVD risk more potently. While human studies show HDL play a key role in reducing CVD risk, recent findings indicate that factors such as diet, genetics, glycosylation, and gut microbes modulate HDL function at the individual level, underscoring the need for precision nutrition strategies that account for personalized variability to optimize HDL's potential for mitigating CVD risk.

RNA modifications in aging-associated cardiovascular diseases

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide that bears an enormous healthcare burden and aging is a major contributing factor to CVDs. Functional gene expression network during aging is regulated by mRNAs transcriptionally and by non-coding RNAs epi-transcriptionally. RNA modifications alter the stability and function of both mRNAs and non-coding RNAs and are involved in differentiation, development, and diseases. Here we review major chemical RNA modifications on mRNAs and non-coding RNAs, including N6-adenosine methylation, N1-adenosine methylation, 5-methylcytidine, pseudouridylation, 2′ -O-ribose-methylation, and N7-methylguanosine, in the aging process with an emphasis on cardiovascular aging. We also summarize the currently available methods to detect RNA modifications and the bioinformatic tools to study RNA modifications. More importantly, we discussed the specific implication of the RNA modifications on mRNAs and non-coding RNAs in the pathogenesis of aging-associated CVDs, including atherosclerosis, hypertension, coronary heart diseases, congestive heart failure, atrial fibrillation, peripheral artery disease, venous insufficiency, and stroke.

The roles and mechanisms of epigenetic regulation in pathological myocardial remodeling

Pathological myocardial remodeling was still one of the leading causes of death worldwide with an unmet therapeutic need. A growing number of researchers have addressed the role of epigenome changes in cardiovascular diseases, paving the way for the clinical application of novel cardiovascular-related epigenetic targets in the future. In this review, we summarized the emerged advances of epigenetic regulation, including DNA methylation, Histone posttranslational modification, Adenosine disodium triphosphate (ATP)-dependent chromatin remodeling, Non-coding RNA, and RNA modification, in pathological myocardial remodeling. Also, we provided an overview of the mechanisms that potentially involve the participation of these epigenetic regulation.

Role of m6A Methylation in the Occurrence and Development of Heart Failure

N6-methyladenosine (m6A) RNA methylation is one of the most common epigenetic modifications in RNA nucleotides. It is known that m6A methylation is involved in regulation, including gene expression, homeostasis, mRNA stability and other biological processes, affecting metabolism and a variety of biochemical regulation processes, and affecting the occurrence and development of a variety of diseases. Cardiovascular disease has high morbidity, disability rate and mortality in the world, of which heart failure is the final stage. Deeper understanding of the potential molecular mechanism of heart failure and exploring more effective treatment strategies will bring good news to the sick population. At present, m6A methylation is the latest research direction, which reveals some potential links between epigenetics and pathogenesis of heart failure. And m6A methylation will bring new directions and ideas for the prevention, diagnosis and treatment of heart failure. The purpose of this paper is to review the physiological and pathological mechanisms of m6A methylation that may be involved in cardiac remodeling in heart failure, so as to explain the possible role of m6A methylation in the occurrence and development of heart failure. And we hope to help m6A methylation obtain more in-depth research in the occurrence and development of heart failure.

Emerging role of m6 A modification in cardiovascular diseases

Cardiovascular diseases (CVDs) contribute to the leading cause of death worldwide. Despite significantly improvements in CVDs diagnosis and treatment, a continued effort to explore novel therapeutic strategies is urgently need. N6-methyladenosine (m⁶ A) RNA methylation, well known as the most prevalent type of RNA modifications, involved in RNA stability, nuclear exports, translation and decoy, plays a crucial role in the pathogenesis of a variety of diseases, including CVDs, cancer and drug resistance. Here, our article summarizes cellular functions of m⁶ A modulators and recent research progress concerning the functions and mechanisms of m⁶ A methylation in CVDs, in hope of providing references for exploring novel therapeutic approaches and potential biomarkers in the treatment of CVDs. This article is protected by copyright. All rights reserved.

Relevance of N6-methyladenosine regulators for transcriptome: Implications for development and the cardiovascular system

N6-methyladenosine (m6A) is the most abundant and well-studied internal modification of messenger RNAs among the various RNA modifications in eukaryotic cells. Moreover, it is increasingly recognized to regulate non-coding RNAs. The dynamic and reversible nature of m6A is ensured by the precise and coordinated activity of specific proteins able to insert ("write"), bind ("read") or remove ("erase") the m6A modification from coding and non-coding RNA molecules. Mounting evidence suggests a pivotal role for m6A in prenatal and postnatal development and cardiovascular pathophysiology. In the present review we summarise and discuss the major functions played by m6A RNA methylation and its components particularly referring to the cardiovascular system. We present the methods used to study m6A and the most abundantly methylated RNA molecules. Finally, we highlight the possible involvement of the m6A mark in cardiovascular disease as well as the need for further studies to better describe the mechanisms of action and the potential therapeutic role of this RNA modification.

Protective mechanism of demethylase fat mass and obesity-associated protein in energy metabolism disorder of hypoxia-reoxygenation-induced cardiomyocytes

NEW FINDINGS

What is the central question of this study? What is the effect of fat mass and obesity-associated protein (FTO) on energy metabolism in hypoxia-reoxygenation (H/R)-induced cardiomyocytes? What is the main finding and its importance? FTO modification of N⁶ -methyladenosine (m⁶ A) is associated with myocardial cell energy metabolism disorder. FTO reduced the m⁶ A level of sarcoplasmic/endoplasmic reticulum calcium ATPase 2a (SERCA2a) mRNA through demethylation, thus promoting SERCA2a expression, maintaining calcium homeostasis, and improving energy metabolism of H/R cardiomyocytes.

ABSTRACT

Energy metabolism disorder is the initial physiological link of myocardial ischaemia-reperfusion injury. Fat mass and obesity-associated protein (FTO) is an N⁶ -methyladenosine (m⁶ A) demethylase implicated in several cardiac defects. This study sought to investigate the effect of FTO on energy metabolism in hypoxia-reoxygenation (H/R)-induced cardiomyocytes. FTO and sarcoplasmic/endoplasmic reticulum calcium ATPase 2a (SERCA2a) expression in H/R-induced cardiomyocytes were determined. Cardiomyocyte viability, cytotoxicity and apoptosis were measured. The total RNA and polyA⁺ RNA contents were isolated from cells. The m⁶ A level of RNA and the enrichment of m⁶ A of SERCA2a mRNA were calculated. Several indices such as the glycolytic potential, reactive oxygen species (ROS), mitochondrial activity and ATP content were evaluated. The concentration of calcium in cardiomyocytes was determined. FTO and SERCA2a were poorly expressed in H/R-induced cardiomyocytes. There was an elevated m⁶ A level in total RNA and enrichment of m⁶ A in SERCA2a mRNA. H/R treatment reduced the cell viability, mitochondrial membrane potential and ATP content in cardiomyocytes, but increased the cytotoxicity, apoptosis, ROS content and calcium concentration. Upregulation of FTO reversed the preceding findings with downregulation of the m⁶ A level of SERCA2a mRNA. Downregulation of SERCA2a annulled the promoting effect of FTO on calcium homeostasis and energy metabolism in H/R-induced cardiomyocytes. Collectively, the current study demonstrated that FTO reduced the m⁶ A level on SERCA2a mRNA through demethylation, thus promoting SERCA2a expression, maintaining calcium homeostasis and improving the energy metabolism of H/R cardiomyocytes.

Integrated analysis of m6A mRNA methylation in rats with monocrotaline-induced pulmonary arterial hypertension

Background: N6-methyladenosine (m⁶A) modification is one of the most common chemical modifications of eukaryotic mRNAs, which play an important role in tumors and cardiovascular disease through regulating mRNA stability, splicing and translation. However, the changes of m⁶A mRNA and m⁶A-related enzymes in pulmonary arterial hypertension (PAH) remain largely unexplored.

Methods: MeRIP-seq was used to identify m⁶A methylation in lung tissues from control and MCT-PAH rats. Western blot and immunofluorescence were used to evaluate expression of m⁶A-related enzymes.

Results: Compared with control group, m⁶A methylation was mainly increased in lung tissues from MCT-PAH rats. The up-methylated coding genes in MCT-PAH rats were primarily enriched in processes associated with inflammation, glycolysis, ECM-receptor interaction and PDGF signal pathway, while genes with down-methylation were enriched in processes associated with TGF-β family receptor members. The expression of FTO and ALKBH5 downregulated, METTL3 and YTHDF1 increased and other methylation modification-related proteins was not significantly changed in MCT-PAH rats lung tissues. Immunofluorescence indicated that expression of FTO decreased and YTHDF1 increased in small pulmonary arteries of MCT-PAH rats.

Conclusion: m⁶A levels and the expression of methylation-related enzymes were altered in PAH rats, in which FTO and YTHDF1 may play a crucial role in m⁶A modification.

Comprehensive Analysis of the Transcriptome-Wide m6A Methylome in Pterygium by MeRIP Sequencing

Aim

Pterygium is a common ocular surface disease, which is affected by a variety of factors. Invasion of the cornea can cause severe vision loss. N6-methyladenosine (m6A) is a common post-transcriptional modification of eukaryotic mRNA, which can regulate mRNA splicing, stability, nuclear transport, and translation. To our best knowledge, there is no current research on the mechanism of m6A in pterygium.

Methods

We obtained 24 pterygium tissues and 24 conjunctival tissues from each of 24 pterygium patients recruited from Shanghai Yangpu Hospital, and the level of m6A modification was detected using an m6A RNA Methylation Quantification Kit. Expression and location of METTL3, a key m6A methyltransferase, were identified by immunostaining. Then we used m6A-modified RNA immunoprecipitation sequencing (MeRIP-seq), RNA sequencing (RNA-seq), and bioinformatics analyses to compare the differential expression of m6A methylation in pterygium and normal conjunctival tissue.

Results

We identified 2,949 dysregulated m6A peaks in pterygium tissue, of which 2,145 were significantly upregulated and 804 were significantly downregulated. The altered m6A peak of genes were found to play a key role in the Hippo signaling pathway and endocytosis. Joint analyses of MeRIP-seq and RNA-seq data identified 72 hypermethylated m6A peaks and 15 hypomethylated m6A peaks in mRNA. After analyzing the differentially methylated m6A peaks and synchronously differentially expressed genes, we searched the Gene Expression Omnibus database and identified five genes related to the development of pterygium (DSP, MXRA5, ARHGAP35, TMEM43, and OLFML2A).

Conclusion

Our research shows that m6A modification plays an important role in the development of pterygium and can be used as a potential new target for the treatment of pterygium in the future.

Epigenetic role of N6-methyladenosine (m6A) RNA methylation in the cardiovascular system

As the most prevalent and abundant transcriptional modification in the eukaryotic genome, the continuous and dynamic regulation of N6-methyladenosine (m6A) has been shown to play a vital role in physiological and pathological processes of cardiovascular diseases (CVDs), such as ischemic heart failure (HF), myocardial hypertrophy, myocardial infarction (MI), and cardiomyogenesis. Regulation is achieved by modulating the expression of m6A enzymes and their downstream cardiac genes. In addition, this process has a major impact on different aspects of internal biological metabolism and several other external environmental effects associated with the development of CVDs. However, the exact molecular mechanism of m6A epigenetic regulation has not been fully elucidated. In this review, we outline recent advances and discuss potential therapeutic strategies for managing m6A in relation to several common CVD-related metabolic disorders and external environmental factors. Note that an appropriate understanding of the biological function of m6A in the cardiovascular system will pave the way towards exploring the mechanisms responsible for the development of other CVDs and their associated symptoms. Finally, it can provide new insights for the development of novel therapeutic agents for use in clinical practice.

mRNA modifications in cardiovascular biology and disease: with a focus on m6A modification

Among several known RNA modifications, N6-methyladenosine (m6A) is the most studied RNA epitranscriptomic modification and controls multiple cellular functions during development, differentiation, and disease. Current research advancements have made it possible to examine the regulatory mechanisms associated with RNA methylation and reveal its functional consequences in the pathobiology of many diseases, including heart failure. m6A methylation has been described both on coding (mRNA) and non-coding RNA species including rRNA, tRNA, small nuclear RNA and circular RNAs. The protein components which catalyze the m6A methylation are termed methyltransferase or "m6A writers." The family of proteins that recognize this methylation are termed "m6A readers" and finally the enzymes involved in the removal of a methyl group from RNA are known as demethylases or "m6A erasers." At the cellular level, different components of methylation machinery are tightly regulated by many factors to maintain the m6A methylation dynamics. The m6A methylation process impacts different stages of mRNA metabolism and the biogenesis of long non-coding RNA and miRNA. Although, mRNA methylation was initially described in the 1970s, its regulatory roles in various diseases, including cardiovascular diseases are broadly unexplored. Recent investigations suggest the important role of m6A mRNA methylation in both hypertrophic and ischemic heart diseases. In the present review, we evaluate the significance of m6A methylation in the cardiovascular system, in cardiac homeostasis and disease, all of which may help to improve therapeutic intervention for the treatment of heart failure.

Transcriptome-wide N6-methyladenosine methylation landscape of coronary artery disease

Aim: To reveal transcriptome-wide N6-methyladenosine (m6A) methylome of coronary artery disease (CAD). Materials & methods: The m6A levels of RNA from peripheral blood mononuclear cells measured by colorimetry were significantly decreased in CAD cases. Transcriptome-wide m6A methylome profiled by methylated RNA immunoprecipitation sequencing (MeRIP-seq) identified differentially methylated m6A sites within both mRNAs and lncRNAs between CAD and control group. Results: Bioinformatic analysis indicated that differentially methylated genes were involved in the pathogenesis of atherosclerosis. MeRIP-quantitative real-time PCR assay confirmed the reliability of MeRIP-seq data. Finally, the rat carotid artery balloon injury model was performed to confirm the role of m6A demethylase FTO in neointima formation. Conclusion: Our study provided a resource of differentially methylated m6A profile for uncovering m6A biological functions in the pathogenesis of CAD.

Comprehensive Analysis of the Transcriptome-Wide m6A Methylome of Heart via MeRIP After Birth: Day 0 vs. Day 7

Aim: To systematically classify the profile of the RNA m6A modification landscape of neonatal heart regeneration.

Materials and Methods: Cardiomyocyte proliferation markers were detected via immunostaining. The expression of m6A modification regulators was detected using quantitative real-time PCR (qPCR) and Western blotting. Genome-wide profiling of methylation-modified transcripts was conducted with methylation-modified RNA immunoprecipitation sequencing (m6A-RIP-seq) and RNA sequencing (RNA-seq). The Gene Expression Omnibus database (GEO) dataset was used to verify the hub genes.

Results: METTL3 and the level of m6A modification in total RNA was lower in P7 rat hearts than in P0 ones. In all, 1,637 methylation peaks were differentially expressed using m6A-RIP-seq, with 84 upregulated and 1,553 downregulated. Furthermore, conjoint analyses of m6A-RIP-seq, RNA-seq, and GEO data generated eight potential hub genes with differentially expressed hypermethylated or hypomethylated m6A levels.

Conclusion: Our data provided novel information on m6A modification changes between Day 0 and Day 7 cardiomyocytes, which identified that increased METTL3 expression may enhance the proliferative capacity of neonatal cardiomyocytes, providing a theoretical basis for future clinical studies on the direct regulation of m6A in the proliferative capacity of cardiomyocytes.

RNA Modification by m6A Methylation in Cardiovascular Disease

Cardiovascular disease is currently the leading cause of death worldwide, and its underlying regulatory mechanisms remain largely unknown. N6-Methyladenosine (m6A) RNA methylation is an epigenetic modification involved in the splicing, nuclear export, translational regulation, and degradation of RNA. After the initial identification of m6A RNA methylation in 1974, the rise of next-generation sequencing technology to detect m6A throughout the transcriptome led to its renewed recognition in 2012. Since that time, m6A methylation has been extensively studied, and its functions, mechanisms, and effectors (e.g., METTL3, FTO, METTL14, WTAP, ALKBH5, and YTHDFs) in various diseases, including cardiovascular diseases, have rapidly been investigated. In this review, we first examine and summarize the molecular and cellular functions of m6A methylation and its readers, writers, and erasers in the cardiovascular system. Finally, we discuss future directions for m6A methylation research and the potential for therapeutic targeting of m6A modification in cardiovascular disease.

FTO overexpression inhibits apoptosis of hypoxia/reoxygenation-treated myocardial cells by regulating m6A modification of Mhrt

Heart failure (HF) is the end stage of many cardiovascular diseases and seriously threatens people's health. This article aimed to explore the biological role of fat-mass and obesity-associated gene (FTO) in HF. We constructed HF mouse model by transverse aortic constriction or intraperitoneal injection of doxorubicin. Mouse myocardial cells were exposed to hypoxia/reoxygenation (H/R). FTO and Mhrt were downregulated in heart tissues of HF mice. HF mice exhibited an increase in the total levels of N⁶ methyladenosine (m⁶A) and the m⁶A levels of Mhrt. Moreover, FTO overexpression caused an upregulation of Mhrt and reduced m⁶A modification of Mhrt in the H/R-treated myocardial cells. FTO upregulation repressed apoptosis of H/R-treated myocardial cells. FTO knockdown had the opposite results. Mhrt overexpression reduced apoptosis of H/R-treated myocardial cells. Moreover, the influence conferred by FTO upregulation was abolished by Mhrt knockdown. In conclusion, our data demonstrate that FTO overexpression inhibits apoptosis of hypoxia/reoxygenation-treated myocardial cells by regulating m6A modification of Mhrt. Thus, FTO may be a target gene for HF treatment.

Therapeutic potential of ALKB homologs for cardiovascular disease

Cardiovascular diseases (CVDs) are the leading causes of human death. Recently, ALKB homologs, including ALKBH1-8 and FTO, have been found to have a variety of biological functions, such as histone demethylation, RNA demethylation, and DNA demethylation. These functions may regulate the physiological and pathological processes of CVDs, including inflammation, oxidative stress, cell apoptosis, and mitochondrial, endothelial, and fat metabolism dysfunction. In the present review, we summarize the biological functions of ALKB homologs and the relationship between the ALKB homologs and CVDs. Importantly, we discuss the roles of ALKB homologs in the regulation of oxidative stress, inflammation, autophagy, and DNA damage in CVDs, as well as the practical applications of ALKB homologs inhibitors or agonists in treating CVDs. In conclusion, the ALKBH family might be a promising target for CVDs therapy.

Epigenetic Regulation of Endothelial Cell Function by Nucleic Acid Methylation in Cardiac Homeostasis and Disease

Pathological remodelling of the myocardium, including inflammation, fibrosis and hypertrophy, in response to acute or chronic injury is central in the development and progression of heart failure (HF). While both resident and infiltrating cardiac cells are implicated in these pathophysiological processes, recent evidence has suggested that endothelial cells (ECs) may be the principal cell type responsible for orchestrating pathological changes in the failing heart. Epigenetic modification of nucleic acids, including DNA, and more recently RNA, by methylation is essential for physiological development due to their critical regulation of cellular gene expression. As accumulating evidence has highlighted altered patterns of DNA and RNA methylation in HF at both the global and individual gene levels, much effort has been directed towards defining the precise role of such cell-specific epigenetic changes in the context of HF. Considering the increasingly apparent crucial role that ECs play in cardiac homeostasis and disease, this article will specifically focus on nucleic acid methylation (both DNA and RNA) in the failing heart, emphasising the key influence of these epigenetic mechanisms in governing EC function. This review summarises current understanding of DNA and RNA methylation alterations in HF, along with their specific role in regulating EC function in response to stress (e.g. hyperglycaemia, hypoxia). Improved appreciation of this important research area will aid in further implicating dysfunctional ECs in HF pathogenesis, whilst informing development of EC-targeted strategies and advancing potential translation of epigenetic-based therapies for specific targeting of pathological cardiac remodelling in HF.

Function and evolution of RNA N6-methyladenosine modification

N6-methyladenosine (m⁶A) is identified as the most prevalent and abundant internal RNA modification, especially within eukaryotic mRNAs, which has attracted much attention in recent years since its importance for regulating gene expression and deciding cell fate. m⁶A modification is installed by RNA methyltransferases METTL3, METTL14 and WTAP (Writers), removed by the demethylases FTO and ALKBH5 (Erasers) and recognized by m⁶A binding proteins, such as YT521-B homology YTH domain-containing proteins (Readers). Accumulating evidence shows that m⁶A RNA methylation participates in almost all aspects of RNA processing, implying an association with important bioprocesses. In this review, we mainly summarize and discuss the functional relevance and importance of m⁶A modification in cellular processes.

FTO-Dependent N6-Methyladenosine Regulates Cardiac Function During Remodeling and Repair

BACKGROUND

Despite its functional importance in various fundamental bioprocesses, studies of N⁶-methyladenosine (m6A) in the heart are lacking. Here, we show that the FTO (fat mass and obesity-associated protein), an m6A demethylase, plays a critical role in cardiac contractile function during homeostasis, remodeling, and regeneration.

METHODS

We used clinical human samples, preclinical pig and mouse models, and primary cardiomyocyte cell cultures to study the functional role of m6A and FTO in the heart and in cardiomyocytes. We modulated expression of FTO by using adeno-associated virus serotype 9 (in vivo), adenovirus (both in vivo and in vitro), and small interfering RNAs (in vitro) to study its function in regulating cardiomyocyte m6A, calcium dynamics and contractility, and cardiac function postischemia. We performed methylated (m6A) RNA immunoprecipitation sequencing to map transcriptome-wide m6A, and methylated (m6A) RNA immunoprecipitation quantitative polymerase chain reaction assays to map and validate m6A in individual transcripts, in healthy and failing hearts, and in myocytes.

RESULTS

We discovered that FTO has decreased expression in failing mammalian hearts and hypoxic cardiomyocytes, thereby increasing m6A in RNA and decreasing cardiomyocyte contractile function. Improving expression of FTO in failing mouse hearts attenuated the ischemia-induced increase in m6A and decrease in cardiac contractile function. This is performed by the demethylation activity of FTO, which selectively demethylates cardiac contractile transcripts, thus preventing their degradation and improving their protein expression under ischemia. In addition, we demonstrate that FTO overexpression in mouse models of myocardial infarction decreased fibrosis and enhanced angiogenesis.

CONCLUSIONS

Collectively, our study demonstrates the functional importance of the FTO-dependent cardiac m6A methylome in cardiac contraction during heart failure and provides a novel mechanistic insight into the therapeutic mechanisms of FTO.

Relationships between FTO rs9939609, MC4R rs17782313, and PPARγ rs1801282 polymorphisms and the occurrence of selected metabolic and hormonal disorders in middle-aged and elderly men - a preliminary study

PURPOSE

Metabolic disorders, including MetS, obesity, and lipid disorders, may be related to genetic factors. Metabolic disorders are associated with decreased TS levels in aging men. The aim of this study was to evaluate the relationship between FTO rs9939609, MC4R rs17782313, and PPARγ rs1801282 polymorphisms and the presence of MetS and its components, the concurrent lipid disorders, as well as sex hormone concentrations.

SUBJECTS AND METHODS

This study involved 272 men of Caucasian descent aged 50-75 years. Lipid profile, including TCh, LDL, HDL, and TG, was evaluated by spectrophotometric method. Anthropometric measurements concerned WC and blood pressure. MetS was diagnosed according to the criteria of the IDF. Sex hormone profile, including TST, FTS, E2, DHEAS, and SHBG, was examined using enzyme-linked immunosorbent assay. Polymorphisms within FTO, MC4R, and PPARγ genes were identified using polymerase chain reaction-restriction fragments length polymorphism.

RESULTS

This study did not show links between the analyzed genetic polymorphisms and the presence of MetS, T2DM, HT, and obesity. However, higher concentrations of TCh and LDL were found in men with the FTO rs9939609 polymorphism in the recessive mode of inheritance (P=0.03 and P=0.05, respectively). Lower WC was found to be associated with MC4R rs17782313 gene inherited in the same model (P=0.005).

CONCLUSION

FTO rs9939609, MC4R rs17782313, and PPARγ rs1801282 polymorphisms seem to have little effect on the incidence of metabolic malfunctions and no effect on androgen-related disorders in the examined middle-aged and elderly men.

The Role of FTO and Vitamin D for the Weight Loss Effect of Roux-en-Y Gastric Bypass Surgery in Obese Patients

BACKGROUND

A recent study in children demonstrated that the rs9939609 single-nucleotide polymorphism in the fat mass and obesity (FTO) gene influences prospective weight gain, however, only in those who were vitamin D-deficient. If this might also be the case for Roux-en-Y gastric bypass (RYGB), surgery-induced weight loss is however unknown. The objective of this study is to examine if the magnitude of RYGB surgery-induced weight loss after 2 years depends on patients' FTO rs9939609 genotype (i.e., TT, AT, and AA) and presurgery vitamin D status (<50 nmol/L equals deficiency).

METHODS

Before and at 24 months after RYGB surgery, BMI was measured in 210 obese patients (mean BMI 45 kg/m(2), 72 % females). Serum 25-hydroxyvitamin D3 levels were also repeatedly measured. Following surgery, vitamin D was supplemented. Possible weight loss differences between genotypes were tested with multiple linear regressions.

RESULTS

The per-allele effect of each FTO A-allele on excessive BMI loss (EBMIL) was 3 % (P = 0.02). When split by baseline status, the EBMIL of vitamin D-deficient patients carrying AA exceeded that of vitamin D-deficient patients carrying TT by ~14 % (P = 0.03). No such genotypic differences were found in patients without presurgery vitamin D deficiency. Post-surgery serum levels of vitamin D did not differ between groups.

CONCLUSIONS

Our data suggest that presurgery vitamin D levels influence the size of genotype effects of FTO rs9939609 on RYGB surgery-induced weight loss in obese patients.

Changes in Physical Activity Following a Genetic-Based Internet-Delivered Personalized Intervention: Randomized Controlled Trial (Food4Me)

Background

There is evidence that physical activity (PA) can attenuate the influence of the fat mass- and obesity-associated (FTO) genotype on the risk to develop obesity. However, whether providing personalized information on FTO genotype leads to changes in PA is unknown.

Objective

The purpose of this study was to determine if disclosing FTO risk had an impact on change in PA following a 6-month intervention.

Methods

The single nucleotide polymorphism (SNP) rs9939609 in the FTO gene was genotyped in 1279 participants of the Food4Me study, a four-arm, Web-based randomized controlled trial (RCT) in 7 European countries on the effects of personalized advice on nutrition and PA. PA was measured objectively using a TracmorD accelerometer and was self-reported using the Baecke questionnaire at baseline and 6 months. Differences in baseline PA variables between risk (AA and AT genotypes) and nonrisk (TT genotype) carriers were tested using multiple linear regression. Impact of FTO risk disclosure on PA change at 6 months was assessed among participants with inadequate PA, by including an interaction term in the model: disclosure (yes/no) × FTO risk (yes/no).

Results

At baseline, data on PA were available for 874 and 405 participants with the risk and nonrisk FTO genotypes, respectively. There were no significant differences in objectively measured or self-reported baseline PA between risk and nonrisk carriers. A total of 807 (72.05%) of the participants out of 1120 in the personalized groups were encouraged to increase PA at baseline. Knowledge of FTO risk had no impact on PA in either risk or nonrisk carriers after the 6-month intervention. Attrition was higher in nonrisk participants for whom genotype was disclosed (P=.01) compared with their at-risk counterparts.

Conclusions

No association between baseline PA and FTO risk genotype was observed. There was no added benefit of disclosing FTO risk on changes in PA in this personalized intervention. Further RCT studies are warranted to confirm whether disclosure of nonrisk genetic test results has adverse effects on engagement in behavior change.

Trial Registration

ClinicalTrials.gov NCT01530139; http://clinicaltrials.gov/show/NCT01530139 (Archived by WebCite at: http://www.webcitation.org/6XII1QwHz)

A patient with a novel homozygous missense mutation in FTO and concomitant nonsense mutation in CETP

The fat mass and obesity associated gene (FTO) has previously been associated with a variety of diseases and conditions, notably obesity, acute coronary syndrome and metabolic syndrome. Reports describing mutations in FTO as well as FTO animal models have further demonstrated a role for FTO in the development of the brain and other organs. Here, we describe a patient born of consanguineous union who presented with microcephaly, developmental delay, behavioral abnormalities, dysmorphic facial features, hypotonia, and other various phenotypic abnormalities. Whole exome sequencing revealed a novel homozygous missense mutation in FTO and a nonsense mutation in the cholesteryl ester transfer protein (CETP). Exome CNV analysis revealed no disease causing large duplications or deletions within coding regions. Patient’s, her parents’ and non-related control’ fibroblasts were analyzed for morphologic defects, abnormal proliferation, apoptosis and transcriptome profile. We have shown that FTO is located in nucleus of cells from each tested samples. Western blot analysis demonstrated no changes in patient FTO. Q-PCR analysis revealed slightly decreased levels of FTO expression in patient cells compared to controls. No morphological or proliferation differences between the patient and control fibroblasts were observed. There is still much to be learned about the molecular mechanisms by which mutations in FTO contribute to such severe phenotypes.

Milk: an epigenetic amplifier of FTO-mediated transcription? Implications for Western diseases

Single-nucleotide polymorphisms within intron 1 of the FTO (fat mass and obesity-associated) gene are associated with enhanced FTO expression, increased body weight, obesity and type 2 diabetes mellitus (T2DM). The N⁶-methyladenosine (m⁶A) demethylase FTO plays a pivotal regulatory role for postnatal growth and energy expenditure. The purpose of this review is to provide translational evidence that links milk signaling with FTO-activated transcription of the milk recipient. FTO-dependent demethylation of m⁶A regulates mRNA splicing required for adipogenesis, increases the stability of mRNAs, and affects microRNA (miRNA) expression and miRNA biosynthesis. FTO senses branched-chain amino acids (BCAAs) and activates the nutrient sensitive kinase mechanistic target of rapamycin complex 1 (mTORC1), which plays a key role in translation. Milk provides abundant BCAAs and glutamine, critical components increasing FTO expression. CpG hypomethylation in the first intron of FTO has recently been associated with T2DM. CpG methylation is generally associated with gene silencing. In contrast, CpG demethylation generally increases transcription. DNA de novo methylation of CpG sites is facilitated by DNA methyltransferases (DNMT) 3A and 3B, whereas DNA maintenance methylation is controlled by DNMT1. MiRNA-29s target all DNMTs and thus reduce DNA CpG methylation. Cow´s milk provides substantial amounts of exosomal miRNA-29s that reach the systemic circulation and target mRNAs of the milk recipient. Via DNMT suppression, milk exosomal miRNA-29s may reduce the magnitude of FTO methylation, thereby epigenetically increasing FTO expression in the milk consumer. High lactation performance with increased milk yield has recently been associated with excessive miRNA-29 expression of dairy cow mammary epithelial cells (DCMECs). Notably, the galactopoietic hormone prolactin upregulates the transcription factor STAT3, which induces miRNA-29 expression. In a retrovirus-like manner milk exosomes may transfer DCMEC-derived miRNA-29s and bovine FTO mRNA to the milk consumer amplifying FTO expression. There is compelling evidence that obesity, T2DM, prostate and breast cancer, and neurodegenerative diseases are all associated with increased FTO expression. Maximization of lactation performance by veterinary medicine with enhanced miRNA-29s and FTO expression associated with increased exosomal miRNA-29 and FTO mRNA transfer to the milk consumer may represent key epigenetic mechanisms promoting FTO/mTORC1-mediated diseases of civilization.

Effect of six type II diabetes susceptibility loci and an FTO variant on obesity in Pakistani subjects

The aim of the current study was to analyze the effect of six type II diabetes GWAS loci rs3923113 (GRB14), rs16861329 (ST6GAL1), rs1802295 (VPS26A), rs7178572 (HMG20A), rs2028299 (AP3S2) and rs4812829 (HNF4A), and an FTO polymorphism (rs9939609) on obesity. The probable mechanism of action of these SNPs was analyzed by studying their association with various biochemical and anthropometric parameters. A total of 475 subjects (obese=250, controls=225) were genotyped by TaqMan assay and their lipid profile was determined. Allele/genotype frequencies and an unweighted/weighted gene score were calculated. The effect of the gene score on anthropometric and biochemical parameters was analyzed. The minor allele frequencies of all variants were comparable to that reported in the original studies and were associated with obesity in these Pakistani subjects. Subjects with 9 risk alleles differ from those with <3 and overall there is no significant effect (P-value for trend 0.26). None of the SNPs were associated with any of the serum lipid traits. We are the first to report the association of these T2D SNPs with obesity. In the Pakistani population the reported effect of six SNPs for obesity is similar to that reported for T2D and having a combination of risk alleles on obesity can be considerable. The mechanism of this effect is unclear, but appears not to be mediated by changing serum lipid chemistry.

Increased genetic risk for obesity in premature coronary artery disease

There is ongoing controversy as to whether obesity confers risk for CAD independently of associated risk factors including diabetes mellitus. We have carried out a Mendelian randomization study using a genetic risk score (GRS) for body mass index (BMI) based on 35 risk alleles to investigate this question in a population of 5831 early onset CAD cases without diabetes mellitus and 3832 elderly healthy control subjects, all of strictly European ancestry, with adjustment for traditional risk factors (TRFs). We then estimated the genetic correlation between these BMI and CAD (rg) by relating the pairwise genetic similarity matrix to a phenotypic covariance matrix between these two traits. GRS_BMI significantly (P=2.12 × 10⁻¹²) associated with CAD status in a multivariate model adjusted for TRFs, with a per allele odds ratio (OR) of 1.06 (95% CI 1.042–1.076). The addition of GRS_BMI to TRFs explained 0.75% of CAD variance and yielded a continuous net recombination index of 16.54% (95% CI=11.82–21.26%, P<0.0001). To test whether GRS_BMI explained CAD status when adjusted for measured BMI, separate models were constructed in which the score and BMI were either included as covariates or not. The addition of BMI explained ~1.9% of CAD variance and GRS_BMI plus BMI explained 2.65% of CAD variance. Finally, using bivariate restricted maximum likelihood analysis, we provide strong evidence of genome-wide pleiotropy between obesity and CAD. This analysis supports the hypothesis that obesity is a causal risk factor for CAD.

The 'Fat Mass and Obesity Related' (FTO) gene: Mechanisms of Impact on Obesity and Energy Balance

A cluster of single nucleotide polymorphisms (SNPs) in the first intron of the fat mass and obesity related (FTO) gene were the first common variants discovered to be associated with body mass index and body fatness. This review summarises what has been later discovered about the biology of FTO drawing together information from both human and animal studies. Subsequent work showed that the 'at risk' alleles of these SNPs are associated with greater food intake and increased hunger/lowered satiety, but are not associated with altered resting energy expenditure or low physical activity in humans. FTO is an FE (II) and 2-oxoglutarate dependent DNA/RNA methylase. Contrasting the impact of the SNPs on energy balance in humans, knocking out or reducing activity of the Fto gene in the mouse resulted in lowered adiposity, elevated energy expenditure with no impact on food intake (but the impact on expenditure is disputed). In contrast, overexpression of the gene in mice led to elevated food intake and adiposity, with no impact on expenditure. In rodents, the Fto gene is widely expressed in the brain including hypothalamic nuclei linked to food intake regulation. Since its activity is 2-oxoglutarate dependent it could potentially act as a sensor of citrate acid cycle flux, but this function has been dismissed, and instead it has been suggested to be much more likely to act as an amino acid sensor, linking circulating AAs to the mammalian target of rapamycin complex 1. This may be fundamental to its role in development but the link to obesity is less clear. It has been recently suggested that although the obesity related SNPs reside in the first intron of FTO, they may not only impact FTO but mediate their obesity effects via nearby genes (notably RPGRIP1L and IRX3).

FTO gene variation, macronutrient intake and coronary heart disease risk: a gene-diet interaction analysis

PURPOSE

The fat mass and obesity-associated gene (FTO) is related to obesity and coronary heart disease (CHD). We studied interaction between macronutrient intake and FTO in association with CHD risk or body mass index (BMI).

METHODS

The pooled population-based case-control studies, SHEEP and INTERGENE, included 1,381 first-time CHD patients and 4,290 population controls genotyped for FTO rs9939609 (T/A). Diet data were collected in self-administered food frequency questionnaires. Macronutrients were dichotomized into low/high energy percentages (E%) by median levels in controls. Association of FTO genotype (TA/AA vs. TT) with CHD risk was analysed by multiple logistic regression, and with BMI by multiple linear regression. Interaction between FTO and macronutrient was assessed by introducing an interaction term FTO × macronutrient. Interaction on CHD as deviation from additive effects was assessed by calculating relative excess risk due to interaction.

RESULTS

No statistically significant interaction was found between FTO genotype and any macronutrient on CHD risk or BMI on either the multiplicative or additive scale. However, FTO genotype (TA/AA vs. TT) was associated with significantly increased CHD risk only in subjects with low E% from fat (OR 1.36, 95% CI 1.11-1.66) or saturated fatty acids (OR 1.36, 95% CI 1.10-1.69), or in subjects with high E% from carbohydrate (OR 1.32, 95% CI 1.07-1.61) or protein (OR 1.41, 95% CI 1.13-1.75). Mean BMI was 0.3-0.6 kg/m(2) higher in control subjects with TA/AA compared to TT, regardless of macronutrient E%.

CONCLUSIONS

We found no evidence of interactions between FTO genotype and macronutrient intake on CHD risk or BMI.