Emerging Role and Mechanism of the FTO Gene in Cardiovascular Diseases

Corporate genome screening India (CoGsI) identified genetic variants association with T2D in young Indian professionals

Rising cases of type 2 diabetes (T2D) in India, especially in metropolitan cities is an increasing concern. The individuals that were most affected are young professionals working in the corporate sector. However, the corporate sector has remained the least explored for T2D risk predisposition. Considering corporate employees' lifestyles and the role of gene-environment interaction in T2D susceptibility, the study aims to find genetic variants associated with T2D predisposition. In this first kind of study, 680 young professionals (284 T2D cases, and 396 controls) were diagnosed and screened for 2658 variants on an array designed explicitly for the CoGsI study. The variant filtering was done at Bonferroni p-value of 0.000028. The genetic data was analysed using PLINK v1.09, SPSS, R programming, VEP tool, and FUMA GWAS tool. Interestingly, 42 variants were associated with the T2D risk. Out of 42, three missense variants (rs1402467, rs6050, and rs713598) in Sulfotransferase family 1 C member 4 (SULT1C4), Fibrinogen Alpha Chain (FGA), and Taste 2 Receptor Member 38 (TAS2R38) and two untranslated region (UTR) variants (rs1063320 and rs6296) in Major Histocompatibility Complex, Class I, G (HLA-G) and 5-Hydroxytryptamine Receptor 1B (HTR1B) were associated with the T2D risk. CoGsI identified potential genomic markers increasing susceptibility to the early onset of T2D. Present findings provide insights into mechanisms underlying T2D manifestation in corporate professionals due to genetics interacting with occupational stress and urban lifestyles.

Fat mass and obesity associated gene and homeobox transcription factor iriquois-3 mRNA profiles in the metabolic tissues of zebrafish are modulated by feeding and food deprivation

Fat mass and obesity associated gene (FTO) has been strongly associated with obesity, and it is functionally linked to the homeobox transcription factor iriquois-3 (IRX3). In mammals, FTO and IRX3 are involved in the regulation of food intake and metabolism. This study aimed to determine whether FTO and IRX3are affected by feeding and food unavailability. FTO and IRX3 mRNA and protein were found widely distributed in all tissues examined, including the brain, muscle, gut, and liver. Postprandial increase in the abundance of FTO and IRX3 mRNAs was observed in metabolic tissues of both male and female zebrafish at 1 h post-feeding. Meanwhile, their expression in the brain and gut decreased at 3 h post-feeding, reaching preprandial levels. Additionally, FTO and IRX3 mRNA abundance in examined tissues increased after 7 days of food deprivation, but substantially decreased after refeeding for 24 h. In summary, we report that both FTO and IRX3 are meal-sensitive genes in zebrafish. The fasting-induced increase suggests a possible appetite regulatory role for FTO and IRX3 in zebrafish. These findings highlight the importance of FTO and IRX3 in appetite and metabolic regulation in zebrafish.

Recent Advance in Single-Molecule Fluorescent Biosensors for Tumor Biomarker Detection

The construction of biosensors for specific, sensitive, and rapid detection of tumor biomarkers significantly contributes to biomedical research and early cancer diagnosis. However, conventional assays often involve large sample consumption and poor sensitivity, limiting their further application in real samples. In recent years, single-molecule biosensing has emerged as a robust tool for detecting and characterizing biomarkers due to its unique advantages including simplicity, low sample consumption, ultra-high sensitivity, and rapid assay time. This review summarizes the recent advances in the construction of single-molecule biosensors for the measurement of various tumor biomarkers, including DNAs, DNA modifications, RNAs, and enzymes. We give a comprehensive review about the working principles and practical applications of these single-molecule biosensors. Additionally, we discuss the challenges and limitations of current single-molecule biosensors, and highlight the future directions.

FTO in oral diseases: Functions, mechanisms, and therapeutic potential

Fat mass and obesity-associated protein (FTO) is the first identified N6-methyladenosine (m6A) demethylase widely distributed in various tissues in adults and children. It plays an essential role in diverse mRNA-associated processes including transcriptional stability, selective splicing, mRNA translocation, and also protein translation. Recently, emerging studies have shown that FTO is involved in the genesis and development of oral diseases. However, the correlation between FTO and oral diseases and its specific regulatory mechanism still needs further study. In this review, we will summarize the discovery, distribution, gene expression, protein structure, biological functions, inhibitors, and quantifying methods of FTO, as well as its regulatory role and mechanism in oral diseases. Notably, FTO genetic variants are strongly associated with periodontal diseases (PDs), temporomandibular joint osteoarthritis (TMJOA), and obstructive sleep apnea (OSA). Besides, the latest studies that describe the relationship between FTO and PDs, head and neck squamous cell carcinoma (HNSCCs), TMJOA, and OSA will be discussed. We elaborate on the regulatory roles of FTO in PDs, HNSCCs, and TMJOA, which are modulated through cell proliferation, cell migration, apoptosis, bone metabolism, and immune response. The review will enrich our understanding of RNA epigenetic modifications in oral diseases and present a solid theoretical foundation for FTO to serve as a novel diagnosis and prognostic biomarker for oral diseases.

Regulatory roles of N6-methyladenosine (m6A) methylation in RNA processing and non-communicable diseases

Post-transcriptional RNA modification is an emerging epigenetic control mechanism in cells that is important in many different cellular and organismal processes. N6-methyladenosine (m6A) is one of the most prevalent, prolific, and ubiquitous internal transcriptional alterations in eukaryotic mRNAs, making it an important topic in the field of Epigenetics. m6A methylation acts as a dynamical regulatory process that regulates the activity of genes and participates in multiple physiological processes, by supporting multiple aspects of essential mRNA metabolic processes, including pre-mRNA splicing, nuclear export, translation, miRNA synthesis, and stability. Extensive research has linked aberrations in m6A modification and m6A-associated proteins to a wide range of human diseases. However, the impact of m6A on mRNA metabolism and its pathological connection between m6A and other non-communicable diseases, including cardiovascular disease, neurodegenerative disorders, liver diseases, and cancer remains in fragmentation. Here, we review the existing understanding of the overall role of mechanisms by which m6A exerts its activities and address new discoveries that highlight m6A's diverse involvement in gene expression regulation. We discuss m6A deposition on mRNA and its consequences on degradation, translation, and transcription, as well as m6A methylation of non-coding chromosomal-associated RNA species. This study could give new information about the molecular process, early detection, tailored treatment, and predictive evaluation of human non-communicable diseases like cancer. We also explore more about new data that suggests targeting m6A regulators in diseases may have therapeutic advantages.

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.

Protective effect of vitexin against high fat-induced vascular endothelial inflammation through inhibiting trimethylamine N-oxide-mediated RNA m6A modification

A high-fat diet (HFD) is a major risk factor for cardiovascular disease. However, the specific effects of a HFD on vascular inflammation and the protective role of vitexin, a bioactive compound derived from food, require further research. This study investigated the protective effects of vitexin intervention against HFD-induced vascular inflammation and its underlying mechanism. The results demonstrated that vitexin intervention significantly reduced body weight, serum total cholesterol, and low-density lipoprotein cholesterol levels in HFD-fed mice. Vitexin also improved vascular pathological changes and the inflammatory status in the mice. Furthermore, vitexin intervention reduced serum TMAO levels in HFD-fed mice by altering the gut microbiota composition. The HFD significantly increased N6-methyladenosine (m6A) levels in aorta tissues, while vitexin intervention reversed this abnormal m6A level. Through metabolite affinity responsive target fluorescence quenching and molecular docking assays, it was found that vitexin could directly bind to fat mass and obesity-associated protein (FTO), potentially promoting m6A demethylation. The dose-response relationship between TMAO and inflammation/m6A was further validated in HUVEC cells and in vivo mouse experiments. Specifically, TMAO increased m6A levels and inflammation, while vitexin inhibited TMAO-mediated m6A modification, exhibiting anti-inflammatory effects. In conclusion, this study demonstrates the protective role of vitexin against HFD-induced vascular inflammation by inhibiting TMAO-mediated RNA m6A modification, laying the foundation for the development of functional foods.

The inhibition of FTO attenuates the antifibrotic effect of leonurine in rat cardiac fibroblasts

BACKGROUND

Myocardial fibrosis (MF) is a common pathological condition in cardiovascular diseases that often causes severe cardiac dysfunction. MF is characterized by changes in cardiomyocytes, cardiac fibroblasts (CFs), levels of collagen (Col) -1, -3, and overdeposition of the extracellular matrix. Our previous research showed that leonurine (LE) effectively inhibits collagen synthesis and differentiation of CFs, but the mechanism is not fully elucidated. Recent evidence indicates that fat mass and obesity-associated proteins (FTO) regulates the occurrence and development of MF. This study aimed to explore the role of FTO in the antifibrotic effects of LE.

METHODS

Neonatal rat CFs were isolated, and induced using angiotensin II (Ang II) to establish a cell model of MF. Cell viability, wound healing and transwell assays were used to detect cell activity and migration ability. The protein and mRNA levels of MF-related factors were measured following stimulation with Ang II and LE under normal conditions or after FTO knockdown. The RNA methylation level was measured by dot blot assay.

RESULTS

The results showed that LE (20, 40 μM) was not toxic to normal CFs. LE reduced the proliferation, migration and collagen synthesis of Ang II-induced CFs. Further investigation showed that FTO was downregulated by Ang II stimulation, whereas LE reversed this effect. FTO knockdown facilitated the migration of CFs, upregulated the protein levels of Col-3, α-SMA and Col-1 in Ang II and LE-stimulated CFs, and enhanced the fluorescence intensity of α-SMA. Furthermore, LE reduced N6-methyladenosine (m6A) RNA methylation, which was partially blocked by FTO knockdown. FTO knockdown also reduced the expression levels of p53 protein in Ang II and LE-stimulated CFs.

CONCLUSIONS

Our findings suggest that the inhibition of FTO may attenuate the antifibrotic effect of LE in CFs, suggesting that FTO may serve as a key protein for anti-MF of LE.

Molecular and Cellular Mechanisms Underlying the Cardiac Hypertrophic and Pro-Remodelling Effects of Leptin

Since its initial discovery in 1994, the adipokine leptin has received extensive interest as an important satiety factor and regulator of energy expenditure. Although produced primarily by white adipocytes, leptin can be synthesized by numerous tissues including those comprising the cardiovascular system. Cardiovascular function can thus be affected by locally produced leptin via an autocrine or paracrine manner but also by circulating leptin. Leptin exerts its effects by binding to and activating specific receptors, termed ObRs or LepRs, belonging to the Class I cytokine family of receptors of which six isoforms have been identified. Although all ObRs have identical intracellular domains, they differ substantially in length in terms of their extracellular domains, which determine their ability to activate cell signalling pathways. The most important of these receptors in terms of biological effects of leptin is the so-called long form (ObRb), which possesses the complete intracellular domain linked to full cell signalling processes. The heart has been shown to express ObRb as well as to produce leptin. Leptin exerts numerous cardiac effects including the development of hypertrophy likely through a number of cell signaling processes as well as mitochondrial dynamics, thus demonstrating substantial complex underlying mechanisms. Here, we discuss mechanisms that potentially mediate leptin-induced cardiac pathological hypertrophy, which may contribute to the development of heart failure.

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of type 2 diabetes mellitus and dyslipidemia, but not coronary artery disease in a Chinese Han population

Background

Relationships of the polymorphisms in fat mass and obesity-associated gene (FTO) and peroxisome proliferator-activated receptor delta gene (PPARD) with metabolic-related diseases remain to be clarified.

Methods

One thousand three hundred and eighty-one subjects were enrolled. Metabolic-related diseases including obesity, dyslipidemia, hyperhomocysteinemia, hyperuricemia, hypertension, type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) were defined based on diagnostic criteria. FTO rs9939609 and rs17817449, and PPARD rs2016520 and rs2267668 polymorphisms were genotyped by using polymerase chain reaction-restricted fragment length polymorphism method.

Results

Patients with T2DM or dyslipidemia had a higher frequency of AA, AT or AA + AT genotypes as well as A allele of FTO rs9939609 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.04 for all). Patients with T2DM or dyslipidemia had a higher frequency of GG, GT or GG + GT genotypes as well as G allele of FTO rs17817449 polymorphism than those free of T2DM or dyslipidemia (P ≤ 0.03 for all). Multivariate logistic regression analyses showed that FTO rs9939609 and rs17817449 polymorphisms were independently associated with T2DM as well as dyslipidemia after adjustment for age, sex, smoking and other metabolic diseases. FTO rs9939609 and rs17817449 polymorphisms were not associated with obesity, hyperhomocysteinemia, hyperuricemia, hypertension and CAD. Obese or T2DM carriers of the AA or AT genotype of the FTO rs9939609 polymorphism had a higher prevalence of dyslipidemia compared to non-obese or non-T2DM carriers of the AA or AT genotype (P = 0.03 for both). Among the carriers of GG or GT genotype of the FTO rs17817449 polymorphism, the prevalence of dyslipidemia in obese patients was higher than that in non-obese subjects (P < 0.01). PPARD rs2016520 and rs2267668 polymorphisms were not correlated with any of the metabolic-related diseases in the study population.

Conclusion

Minor alleles of FTO rs9939609 and rs17817449 polymorphisms confer a higher risk of T2DM and dyslipidemia, and the risk is further increased among obese individuals. PPARD rs2016520 and rs2267668 polymorphisms are not associated with metabolic-related diseases.