Differential distribution and association of FTO rs9939609 gene polymorphism with obesity: A cross-sectional study among two tribal populations of India with East-Asian ancestry

RNA modifications in cellular metabolism: implications for metabolism-targeted therapy and immunotherapy

Cellular metabolism is an intricate network satisfying bioenergetic and biosynthesis requirements of cells. Relevant studies have been constantly making inroads in our understanding of pathophysiology, and inspiring development of therapeutics. As a crucial component of epigenetics at post-transcription level, RNA modification significantly determines RNA fates, further affecting various biological processes and cellular phenotypes. To be noted, immunometabolism defines the metabolic alterations occur on immune cells in different stages and immunological contexts. In this review, we characterize the distribution features, modifying mechanisms and biological functions of 8 RNA modifications, including N6-methyladenosine (m6A), N6,2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), 5-methylcytosine (m5C), N4-acetylcytosine (ac4C), N7-methylguanosine (m7G), Pseudouridine (Ψ), adenosine-to-inosine (A-to-I) editing, which are relatively the most studied types. Then regulatory roles of these RNA modification on metabolism in diverse health and disease contexts are comprehensively described, categorized as glucose, lipid, amino acid, and mitochondrial metabolism. And we highlight the regulation of RNA modifications on immunometabolism, further influencing immune responses. Above all, we provide a thorough discussion about clinical implications of RNA modification in metabolism-targeted therapy and immunotherapy, progression of RNA modification-targeted agents, and its potential in RNA-targeted therapeutics. Eventually, we give legitimate perspectives for future researches in this field from methodological requirements, mechanistic insights, to therapeutic applications.

Investigation of associations of European, African, Amerindian genomic ancestries and MC4R, FTO, FAIM2, BDNF loci with obesity-related traits in Rio de Janeiro, Brazil

A complex web of causation is involved in adiposity, including environmental, social and genetic factors. We aimed to investigate associations between genetic factors such as ancestry and single nucleotide polymorphisms, and obesity-related traits in a sampled Brazilian population. A sample of 501 unrelated adults participating in 2013 at the longitudinal Pró-Saúde Study (EPS) in Rio de Janeiro, Brazil was selected. We analysed 46 AIM-InDels (insertion/deletion) as genetic ancestry markers and four single nucleotide polymorphisms located in the genes MC4R (rs17782313), FTO (rs9939609), FAIM2 (rs7138803) and BDNF (rs4074134), previously described as associated with obesity. The selected obesity-related markers were anthropometric parameters such as body mass index, waist circumference and waist-to-hip ratio, and body composition measurements namely body fat percentage, android fat mass and gynoid fat mass. The sample showed greater European ancestry (57.20%), followed by African (28.80%) and lastly Amerindian (14%). Our results suggest that the rs4074134 (BDNF) CC genotype was directly associated with gynoid fat mass, whereas body fat percentage, android fat mass and the anthropometric parameters seem not to be associated with neither ancestry nor the four polymorphisms in this population sample, most likely due to a stronger role of social, behavioural and environmental determinants.

Comprehensive mutations analyses of FTO (fat mass and obesity-associated gene) and their effects on FTO’s substrate binding implicated in obesity

An excessive amount of fat deposition in the body leads to obesity which is a complex disease and poses a generic threat to human health. It increases the risk of various other diseases like diabetes, cardiovascular disease, and multiple types of cancer. Genomic studies have shown that the expression of the fat mass obesity (FTO) gene was highly altered and identified as one of the key biomarkers for obesity. This study has been undertaken to investigate the mutational profile of the FTO gene and elucidates its effect on the protein structure and function. Harmful effects of various missense mutations were predicted using different independent tools and it was observed that all mutations were highly pathogenic. Molecular dynamics (MD) simulations were performed to study the structure and function of FTO protein upon different mutations and it was found that mutations decreased the structure stability and affected protein conformation. Furthermore, a protein residue network analysis suggested that the mutations affected the overall residues bonding and topology. Finally, molecular docking coupled with MD simulation suggested that mutations affected FTO substrate binding by changing the protein-ligand affinity. Hence, the results of this finding would help in an in-depth understanding of the molecular biology of the FTO gene and its variants and lead to the development of effective therapeutics against associated diseases and disorders.

FTO gene polymorphisms and hepatoblastoma susceptibility among Chinese children

Current knowledge on the etiology of hepatoblastoma remains limited. FTO gene has been documented as a susceptibility gene for several types of cancer. However, its role has not been characterized in hepatoblastoma. Herein, we intended to explore whether FTO gene single nucleotide polymorphisms (SNPs) contribute to the risk of hepatoblastoma. A multi-center case-control study was conducted including 358 cases and 1512 controls recruited from the night hospitals in China. Odds ratios (ORs) and 95% confidence intervals (CIs), for the association of FTO gene SNPs with hepatoblastoma risk, were estimated using conditional logistic regression models, adjusted for relevant confounding variables. Four SNPs (rs1477196 G > A, rs9939609 T > A, rs7206790 C > G, and rs8047395 A > G) in the FTO gene were genotyped. We detected a significant association between rs9939609 T > A and decreased risk of hepatoblastoma (TA vs. TT: adjust OR = 0.73, 95% CI = 0.54-0.99, P = 0.041; TA/AA vs. TT: adjust OR = 0.73, 95% CI = 0.55-0.97, P = 0.032). Compared to 0-3 protective genotypes, carriers with four protective genotypes showed enough strength to protect from hepatoblastoma (adjust OR = 0.65, 95% CI = 0.47-0.91, P = 0.012). In stratification analysis, we also detected a significantly decreased risk of hepatoblastoma in subjects with rs9939609 TA/AA or with four protective genotypes in some subgroups. Our results provided some clues for an association of FTO gene SNPs with hepatoblastoma risk in Chinese children.Abbreviations: GWAS, genome-wide association study; FTO, The fat mass and obesity-associated gene; SNP, single nucleotide polymorphism; m⁶A, N6-methyladenosine; mRNA, messenger RNA; LD, linkage disequilibrium; HWE, Hardy-Weinberg equilibrium; OR, odds ratio; CI, confidence interval; AML, acute myeloid leukemia; GSC, glioblastoma stem(-like) cell; HER2, human epidermal growth factor receptor 2.

Obesity, dyslipidaemia and candidate gene polymorphisms: a cross-sectional study among the Liangmai and Mizo tribes of Manipur, India

BACKGROUND

The prevalence of obesity and dyslipidaemia was observed to be increased among the tribal populations, due to globalization.

MATERIALS AND METHODS

In the present study, data on demographic, somatometric and blood samples were collected from 613 participants of both sex, age 18-60 years, further lipid profiling and genotyping was executed. Multifactor dimensionality reduction (MDR) software was used for gene-gene interactions analysis.

RESULTS

Significantly differences were observed with respect to the general characteristic and selected gene polymorphisms in both the tribes. Among the Liangmai tribe, MC4R gene was found to pose significant decreased risk for waist-height ratio (WHtR) (OR = 0.56; 95% confidence interval (CI)= 0.32-0.99; p value = .04) and HDL (OR = 0.58; 95% CI = 0.36-0.92; p value = .02). Similar trends of significant decreased risk (OR = 0.39; 95% CI = 0.20-0.76; p value=.006) for BMI were observed among the Mizo tribe. The gene-gene interaction revealed the combined model of FTO+MC4R genes shows an increased risk for BMI in both the tribes. The independent significant increased risk posed by FTO gene was moderated by interaction with MC4R gene.

CONCLUSIONS

The observed differences can possibly attribute to both their respective ancestries resulting in different gene pools and the physical environment. The results of the study highlight the importance of gene-gene and gene-environment interactions in adverse phenotype groups.KEY MESSAGEAmong the tribal population, the prevalence of obesity and dyslipidaemia has been increased.Differential distribution and associations of selected markers hint towards differential genetic architecture in these populations.MC4R rs17782313 polymorphism was found to show a significantly decreased risk for WHtR and low HDL among the Liangmai tribe and BMI among the Mizo tribe.Significant increased risk posed by FTO rs9939609 gene polymorphism was moderated by the interaction with MC4R rs17782313.

Association of ACE I/D gene polymorphism and related risk factors in impaired fasting glucose and type 2 diabetes: a study among two tribal populations of North-East India

BACKGROUND

Type 2 diabetes is a serious public health concern in India, even the indigenous tribal populations are not left unaffected. The present study aims to understand the association of major risk factors i.e. obesity, hypertension, dyslipidemia, ACE I/D polymorphism with impaired fasting glucose (IFG) and type 2 diabetes (T2D) among two different Mendelian populations of North East India.

METHODS

Demographic, somatometric, physiological variables along with fasting blood samples were collected from 609 individuals. The participants were screened for ACE I/D polymorphism.

RESULTS

ACE I/D polymorphism was found to follow HWE among Liangmai tribe but not among Mizo tribe. Distribution of DD genotype/D allele was found to be significantly higher for T2D among Mizo tribe. Significant association were observed between DD genotype/D allele of ACE I/D polymorphism and TC as well as LDL with both IFG and T2D only in Mizo tribe.

CONCLUSIONS

The present study is an example of gene-environment interaction where DD genotype or D allele and dyslipidemia (high TC and high LDL) are posing risk for IFG and T2D both independently and in combination only among Mizo tribe with relatively less physical activity attributed to their residence in less hilly terrain however Liangmai tribe which resides in high hilly terrain shows no such association.

Role of FTO gene polymorphisms in Wilms tumor predisposition: A five-center case-control study

BACKGROUND

Wilms tumor is the most frequently occurring renal malignancy in pediatrics. The FTO gene exhibits a featured genetic contribution to cancer development. Nonetheless, its single nucleotide polymorphism (SNP) contribution to Wilms tumor remains unknown.

METHODS

In the present study, 402 Wilms tumor patients and 1198 healthy controls were successfully genotyped for FTO gene SNPs (rs1477196 G>A, rs9939609 T>A, rs7206790 C>G and rs8047395 A>G) using TaqMan SNP genotyping assays. Odds ratios (ORs) and 95% confidence intervals (CIs), generated from unconditional logistic regression, were applied to quantify the effects of FTO gene SNPs on Wilms tumor risk.

RESULTS

We found that the rs8047395 A>G polymorphism was significantly correlated with an increased risk for Wilms tumor (GG versus AA/AG: adjusted OR = 1.38, 95% CI = 1.04-1.85, p = 0.027). Carriers with 1 and 1-2 risk genotypes are more susceptible of developing Wilms tumor than those without risk genotypes. Stratified analysis of rs8047395 and risk genotypes revealed more significant relationships with Wilms tumor risk in certain subgroups. Preliminary functional annotations revealed that the rs8047395 A allele increases expression levels of the FTO gene as determined by expression quantitative trait locus analysis.

CONCLUSIONS

The present study provides evidence that rs8047395 may regulate FTO gene expression and thus confer susceptibility to Wilms tumor. The candidate FTO gene rs8047395 A>G polymorphism identified in this study warrants independent investigation.

Fat mass and obesity-associated (FTO) and leptin receptor (LEPR) gene polymorphisms in Egyptian obese subjects

BACKGROUND

Several studies addressed the contribution of fat mass and obesity-associated (FTO) and leptin receptor (LEPR) polymorphisms for the susceptibility to obesity among different ethnic subjects. The main purpose of this work is to evaluate the association of these polymorph\isms with obesity among Egyptian subjects.

SUBJECTS AND METHODS

This case-control study was carried out on 110 unrelated obese Egyptian subjects who were compared with 122 controls. Their genomic DNA was genotyped using the PCR technique.

RESULTS

The allelic frequencies of FTO rs9939609 (A) and LEPR rs1137101 (223R) were significantly higher in obese subjects compared with non-obese controls (p < .001). Comparing different phenotype frequencies including clinical, anthropometric, and biochemical parameters in obese subjects revealed no significant difference in relation to their genotype frequencies (p> .05).

CONCLUSIONS

This study designates a strong association for FTO and LEPR variants with the risk of obesity among Egyptian subjects.

No Association Between FTO Gene Polymorphisms and Central Nervous System Tumor Susceptibility in Chinese Children

Background

Central nervous system (CNS) tumor is a malignancy commonly seen occurring in childhood, worldwide. Fat mass and obesity-associated (FTO) enzyme, initially identified as an obesity-related protein, also functions as a susceptibility gene for cancers. However, predisposing effect of FTO gene single nucleotide polymorphisms (SNPs) on CNS tumor risk remains unknown.

Methods

Herein, we genotyped 314 CNS tumor patients and 380 healthy controls samples from three hospitals to explore whether FTO gene SNPs impact CNS tumor risk. TaqMan SNP genotyping assay was applied for the genotyping. Odds ratios (ORs) and 95% confidence intervals (CIs), generated from multinomial logistic regression, were applied to determine the associations of SNPs (rs1477196 G>A, rs9939609 T>A, rs7206790 C>G, and rs8047395 A>G) in FTO gene with risk of CNS tumor.

Results

We failed to detect significant associations between FTO gene SNPs and CNS tumor risk, either in single-locus or combined analysis. A significantly increased ependymoma risk was found for carriers with 3-4 risk genotypes in comparison to 0-2 risk genotypes (adjusted OR=1.94, 95% CI=1.11-3.37, P=0.020).

Conclusion

Our data indicated that FTO gene SNPs are unlikely to have large effects on CNS tumor risk but may have weaker effects.

The critical roles of m6A modification in metabolic abnormality and cardiovascular diseases

N6-methyladenosine (m6A) RNA methylation is an emerging area of epigenetics, which is a reversible and dynamic modification mediating by ‘writers’ (methylase, adding methyl groups, METTL3, METTL14, and WTAP), ‘erasers’ (demethylase, deleting methyl groups, FTO and ALKBH5), and ‘readers’ (YTHDF1-3, YTHDC1 and YTHDC2). Recent studies in human, animal models and cell levels have disclosed a critical role of m6A modification in regulating the homeostasis of metabolic processes and cardiovascular function. Evidence from these studies identify m6A as a candidate of biomarker and therapeutic target for metabolic abnormality and cardiovascular diseases (CVD). Comprehensive understanding of the complexity of m6A regulation in metabolic diseases and CVD will be helpful for us to understand the pathogenesis of CVD. In this review, we discuss the regulatory role of m6A in metabolic abnormality and CVD. We will emphasize the clinical relevance of m6A dysregulation in CVD.

Investigation of the association between obesity and insulin-induced gene 1 polymorphism at 7q36.3 region in Uygur population in Xinjiang, China

Background: Obesity is a common heritable trait and a major risk factors of chronic and metabolic diseases. Insulin-induced gene 1 (INSIG1) is known to play important roles in cholesterol and triacylglycerol (TAG) metabolism. In the present study, our primary objective was to explore whether the single nucleotide polymorphisms (SNPs) in INSIG1 gene were associated with obesity in Uygur subjects, in Xinjiang, China.

Methods: We designed a case–control study including 516 obese patients and 463 age- and sex-matched control subjects. Three SNPs (rs2721, rs9767875 and rs9719268) were genotyped using TaqMan SNP genotyping assays.

Results: For rs2721, the distribution of genotypes, dominant model (GT + TT vs GG), recessive model (TT vs GT + GG) showed significant differences between obese patients and the controls (P = 0.008, P = 0.005 and P = 0.035, respectively). For rs9719268, the distribution of genotypes showed significant differences between obese patients and the controls (P = 0.004). The dominant model (GT + TT vs GG) of rs2721 and rs9719268 GT genotype remain significantly associated with obesity after adjustment for confounders (OR = 1.393, 95% CI = 1.047–1.853, P = 0.023; OR = 1.631, 95% CI = 1.059–2.512, P = 0.026). The TG levels were significantly higher in rs2721 GT/TT genotypes than that in GG genotypes (P<0.05).

Conclusions: Rs2721 and rs9719268 of INSIG1 gene are associated with obesity in Uygur subjects. Subjects with GT/TT genotype or T allele of rs2721 and GT genotype of rs9719268 were associated with an increased risk of obesity.

Determination of individual type 2 diabetes risk profile in the North East Indian population & its association with anthropometric parameters

Background & objectives:

Diabetes genomics research has illuminated single nucleotide polymorphism (SNP) in several genes including, fat mass and obesity associated (FTO) (rs9939609 and rs9926289), potassium voltage-gated channel subfamily J member 11 (rs5219), SLC30A8 (rs13266634) and peroxisome proliferator-activated receptor gamma 2 (rs1805192). The present study was conducted to investigate the involvement of these polymorphisms in conferring susceptibility to type 2 diabetes (T2D) in the North East Indian population, and also to establish their association with anthropometric parameters.

Methods:

DNA was extracted from blood samples of 155 patients with T2D and 100 controls. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing. To confirm the association between the inheritance of SNP and T2D development, logistic regression analysis was performed.

Results:

For the rs9939609 variant (FTO), the dominant model AA/(AT+TT) revealed significant association with T2D [odds ratio (OR)=2.03, P=0.021], but was non-significant post correction for multiple testing (P=0.002). For the rs13266634 variant (SLC30A8), there was considerable but non-significant difference in the distribution pattern of genotypic polymorphisms between the patients and the controls (P=0.004). Significant association was observed in case of the recessive model (CC+CT)/TT (OR=4.56 P=0.001), after adjusting for age, gender and body mass index. In addition, a significant association (P=0.001) of low-density lipoprotein (mg/dl) could be established with the FTO (rs9926289) polymorphism assuming dominant model.

Interpretation & conclusions:

The current study demonstrated a modest but significant effect of SLC30A8 (rs13266634) polymorphisms on T2D predisposition. Considering the burgeoning prevalence of T2D in the Indian population, the contribution of these genetic variants studied, to the ever-increasing number of T2D cases, appears to be relatively low. This study may serve as a foundation for performing future genome-wide association studies (GWAS) involving larger populations.

Prevalence of obesity in India: A systematic review

Recent studies have reported that globally, more than 1.9 billion adults are overweight and 650 million are obese. Approximately 2.8 million deaths are reported as a result of being overweight or obese. Due to the consumption of energy dense food (i.e. unhealthy food habits), sedentary life style, lack of health care services and financial support, the developing countries are facing high risk of obesity and their adverse consequences (i.e. diabetes, ischemic heart disease, etc). In India, more than 135 million individuals were affected by obesity. The prevalence of obesity in India varies due to age, gender, geographical environment, socio-economic status, etc. According to ICMR-INDIAB study 2015, prevalence rate of obesity and central obesity are varies from 11.8% to 31.3% and 16.9%-36.3% respectively. In India, abdominal obesity is one of the major risk factors for cardiovascular disease (CVDs). Various studies have shown that the prevalence of obesity among women were significantly higher as compared to men. Obesity is one of the main medical and financial burdens for the government. This problem of obesity can be preventable by spreading public awareness about obesity and its health consequences. Governmental agencies should promote the benefits of healthy life style, food habits and physical activity. The aim of this article is to report the prevalence of obesity in different regions of India and highlight the problem areas.

Novel positioning from obesity to cancer: FTO, an m6A RNA demethylase, regulates tumour progression

PURPOSE

The fat mass- and obesity-associated (FTO) gene on chromosome 16q12.2 shows an intimate association with obesity and body mass index. Recently, research into the FTO gene and its expression product has attracted widespread interest due to the identification of FTO as an N6-methyladenosine (m6A) demethylase. FTO primarily regulates the m6A levels of downstream targets via their 3' untranslated regions. FTO not only plays a critical role in obesity-related diseases but also is involved in the occurrence, development and prognosis of many types of cancer, such as acute myeloid leukaemia, glioblastoma and breast cancer. Currently, studies indicate that FTO is a crucial component of m6A modification, it regulates cancer stem cell function, and promotes the growth, self-renewal and metastasis of cancer cells. In this review, we summarized and analysed the data regarding the structural features and biological functions of FTO as well as its association with different cancers and possible molecular mechanisms.

METHODS

We systematically reviewed the related literatures regarding FTO and its demethylation activity in many pathologic and physiological processes, especially in cancer-related diseases based on PubMed databases in this article.

RESULTS

Mounting evidence indicated that FTO plays a critical role in occurrence, progression and treatment of various cancers, even acting as a cancer oncogene in acute myeloid leukaemia, research on which is no longer restricted to metabolic diseases such as obesity and diabetes.

CONCLUSION

Considering FTO's critical role in many diseases, FTO may become a new promising target for the diagnosis and treatment of various diseases in the near future, especially for specific types of cancers, such as acute myeloid leukaemia, glioblastoma and breast cancer.