Fat Mass and Obesity Associated (FTO) Gene and Hepatic Glucose and Lipid Metabolism

Tissue-specific roles of mitochondrial unfolded protein response during obesity

Obesity is a worldwide multifactorial disease caused by an imbalance in energy metabolism, increasing adiposity, weight gain, and promoting related diseases such as diabetes, cardiovascular diseases, neurodegeneration, and cancer. Recent findings have reported that metabolic stress related to obesity induces a mitochondrial stress response called mitochondrial unfolded protein response (UPRmt), a quality control pathway that occurs in a nuclear DNA-mitochondria crosstalk, causing transduction of chaperones and proteases under stress conditions. The duality of UPRmt signaling, with both beneficial and detrimental effects, acts in different contexts depending on the tissue, cell type, and physiological states, affecting the mitochondrial function and efficiency and the metabolism homeostasis during obesity, which remains not fully clarified. Therefore, this review discusses the most recent findings regarding UPRmt signaling during obesity, bringing an overview of UPRmt across different metabolic tissues.

Associations of the obesity gene FTO variant with complications and comorbidities in patients with type 1 diabetes

BACKGROUND AND AIMS

Because FTO gene is connected with the risk of obesity, cardiovascular disease and hypertension, as well as type 2 diabetes, we hypothesize that the rs9939609 FTO polymorphism may affect type 1 diabetes (T1D) complications and comorbidities.

METHODS

We have investigated the associations of the FTO gene variant with the T1D and its complications and comorbidities, as well as the serum levels of pro- and anti-inflammatory markers and lipid profiles.

RESULTS

The key results of our study are as follows: (1) the rs9939609 FTO polymorphism does not predispose individuals to T1D; (2) AA genotype is associated with an increased risk of overweight and obesity, retinopathy, hypertension, dyslipidemia and celiac disease; (3) AT genotype is associated with a decreased risk of retinopathy and celiac disease, whereas TT genotype is connected with decreased risk of dyslipidemia; (4) the FTO rs9939609 polymorphism affects the inflammatory status as well as lipid profile in T1D patients.

CONCLUSIONS

Our results, for the first time, comprehensively indicate that the rs9939609 FTO polymorphism could be considered a genetic marker for increased susceptibility to T1D complications and comorbidities as well as suggests importance of FTO-mediated pathways in their etiology.

FTO attenuates the cytotoxicity of cisplatin in KGN granulosa cell-like tumour cells by regulating the Hippo/YAP1 signalling pathway

Premature ovarian failure (POF) is a devastating condition for women under 40 years old. Chemotherapy, especially the use of cisplatin, has been demonstrated to promote the apoptosis of granulosa cells in primary and secondary follicles, leading to POF. Our previous studies demonstrated that fat mass- and obesity-associated (FTO) plays an essential role in protecting granulosa cells from cisplatin-induced cytotoxicity. Various studies have suggested that the Hippo/YAP signalling pathway plays a significant role in regulating cell apoptosis and proliferation. Additionally, YAP1 is the main downstream target of the Hippo signalling pathway and is negatively regulated by the Hippo signalling pathway. However, whether the Hippo/YAP signalling pathway is involved in the protective effect of FTO on granulosa cells has not been determined. In this study, we found that after cisplatin treatment, the apoptosis of granulosa cells increased in a concentration-dependent manner, accompanied by the downregulation of FTO and YAP1. Furthermore, overexpression of FTO decreased cisplatin-induced granulosa cell apoptosis, inhibited the Hippo/YAP kinase cascade-induced phosphorylation of YAP1, and promoted the entry of YAP1 into the nucleus. The downstream targets of YAP1 (CTGF, CYR61, and ANKRD1) were also increased. Si-RNA-mediated downregulation of FTO promoted cisplatin-induced granulosa cell apoptosis, activated the Hippo/YAP kinase cascade, and inhibited the YAP1 entry into the nucleus. These effects were completely reversed by the small molecule inhibitor of YAP1-verteporfin (VP). Taken together, these data suggested that FTO-YAP1 plays a positive role in regulating the proliferation of injured granulosa cells induced by cisplatin.

Fat mass and obesity-associated (FTO) gene is essential for insulin secretion and β-cell function: In vitro studies using INS-1 cells and human pancreatic islets

AIMS

In this study, we investigated the role of the FTO gene in pancreatic β-cell biology and its association with type 2 diabetes (T2D). To address this issue, human pancreatic islets and rat INS-1 (832/13) cells were used to perform gene silencing, overexpression, and functional analysis of FTO expression; levels of FTO were also measured in serum samples obtained from diabetic and obese individuals.

RESULTS

The findings revealed that FTO expression was reduced in islets from hyperglycemic/diabetic donors compared to normal donors. This reduction correlated with decreased INS and GLUT1 expression and increased PDX1, GCK, and SNAP25 expression. Silencing of Fto in INS-1 cells impaired insulin release and mitochondrial ATP production and increased apoptosis in pro-apoptotic cytokine-treated cells. However, glucose uptake and reactive oxygen species production rates remained unaffected. Downregulation of key β-cell genes was observed following Fto-silencing, while Glut2 and Gck were unaffected. RNA-seq analysis identified several dysregulated genes involved in metal ion binding, calcium ion binding, and protein serine/threonine kinase activity. Furthermore, our findings showed that Pdx1 or Mafa-silencing did not influence FTO protein expression. Overexpression of FTO in human islets promoted insulin secretion and upregulated INS, PDX1, MAFA, and GLUT1 expression. Serum FTO levels did not significantly differ between individuals with diabetes or obesity and their healthy counterparts.

CONCLUSION

These findings suggest that FTO plays a crucial role in β-cell survival, metabolism, and function and point to a potential therapeutic utility of FTO in T2D patients.

Genetic variants of metabolism and inflammatory pathways, and PCOS risk -Systematic review, meta-analysis, and in-silico analysis

IMPORTANCE

Identification of genetic risk factors for PCOS susceptibility.

OBJECTIVE

To identify genetic risk variants of the genes involved in metabolic or inflammatory pathways.

DATA SOURCES

Relevant literature was identified and extracted from PubMed, Central Cochrane Library, Google Scholar, and Science Direct by using a set of keywords related to pre-determined genes up to 06 May 2023. Study selection and synthesis: PRISMA guidelines were followed to design the protocol which is registered in PROSPERO (CRD42023422501). Pooled odds ratio (OR) and 95% confidence interval (95% CI) for different gene variants were calculated under different genetic models (dominant model, recessive model, additive model, and allele model) by using Review Manager software 4.2.

MAIN OUTCOMES

Metabolic genetic variants FTO rs9939609, IL-6 rs1800795 and CAPN10 rs3842570, rs2975760, and RAB5B rs705702 are associated with PCOS risk.

RESULTS

Forty-four relevant articles have been identified for genes involved in metabolic (n = 23) or inflammatory pathways (n = 21). There is a significant association (p < 0.05) of IL-6 rs1800795 and FTO rs9939609 with increased risk.CAPN10 rs2975760 Ins allele is suggested as a protective factor among only the non-Asian population. Also, a significant association of CAPN10 rs2975760 and RAB5B rs705702 with increased risk among the Asian population is suggested. However, no significant association could be found between CAPN10 rs3792267, rs5030952, and SUMO1P1 rs2272046, and the risk of PCOS in any of the subpopulations analysed. In silico analysis suggests the deleterious effect of IL-6 rs1800795.

CONCLUSION

and relevance: The study suggests the role of various genetic variants for genetic predisposition to PCOS among different subpopulations.

Transcriptome-wide map of N6-methyladenosine (m6A) profiling in coronary artery disease (CAD) with clopidogrel resistance

BACKGROUND

Clopidogrel resistance profoundly increases the risk of major cardiovascular events in coronary artery disease (CAD) patients. Here, we comprehensively analyse global m6A modification alterations in clopidogrel-resistant (CR) and non-CR patients.

METHODS

After RNA isolation, the RNA transcriptome expression (lncRNA, circRNA, and mRNA) was analysed via RNA-seq, and m6A peaks were identified by MeRIP-seq. The altered m6A methylation sites on mRNAs, lncRNAs, and circRNAs were identified, and then, GO and KEGG pathway analyses were performed. Through joint analysis with RNA-seq and MeRIP-seq data, differentially expressed mRNAs harbouring differentially methylated sites were identified. The changes in m6A regulator levels and the abundance of differentially methylated sites were measured by RT-PCR. The identification of m6A-modified RNAs was verified by m6A-IP-qPCR.

RESULTS

The expression of 2919 hypermethylated and 2519 hypomethylated mRNAs, 192 hypermethylated and 391 hypomethylated lncRNAs, and 375 hypermethylated and 546 hypomethylated circRNAs was shown to be altered in CR patients. The m6A peaks related to CR indicated lower mark density at the CDS region. Functional enrichment analysis revealed that inflammatory pathways and insulin signalling pathways might be involved in the pathological processes underlying CR. The expression of mRNAs (ST5, KDM6B, GLB1L2, and LSM14B), lncRNAs (MSTRG.13776.1 and ENST00000627981.1), and circRNAs (hsa_circ_0070675_CBC1, hsa-circRNA13011-5_CBC1, and hsa-circRNA6406-3_CBC1) was upregulated in CR patients, while the expression of mRNAs (RPS16 and CREG1), lncRNAs (MSTRG.9215.1), and circRNAs (hsa_circ_0082972_CBC1) was downregulated in CR patients. Moreover, m6A regulators (FTO, YTHDF3, and WTAP) were also differentially expressed. An additional combined analysis of gene expression and m6A peaks revealed that the expression of mRNAs (such as ST5, LYPD2, and RPS16 mRNAs) was significantly altered in the CR patients.

CONCLUSION

The expression of m6A regulators, the RNA transcriptome, and the m6A landscape was altered in CR patients. These findings reveal epitranscriptomic regulation in CR patients, which might be novel therapeutic targets in future.

Therapeutic efficacy of mitochondria-targeted esculetin in the improvement of NAFLD-NASH via modulating AMPK-SIRT1 axis

Mitochondrial dysfunction due to deregulated production of mitochondria-derived ROS is implicated in the development and progression of non-alcoholic fatty liver disease (NAFLD) to non-alcoholic steatohepatitis (NASH). Recently, we synthesized a novel mitochondria-targeted esculetin (Mito-Esc) and investigated its dose-response therapeutic efficacy in mitigating high-fat diet (HFD)-induced NAFLD and NASH in Apoe-/- mice. Mito-Esc administration, compared to simvastatin and pioglitazone, dose-dependently caused a significant reduction in body weight, improved lipid profile, glucose homeostasis, and pro-inflammatory cytokines level. Mito-Esc administration reduced adipose tissue hypertrophy and lipid accumulation presumably by regulating the levels of CD36, PPAR-γ, EBP-α, and their target genes. Mechanistically, Mito-Esc-induced activation of the AMPK1α-SIRT1 axis inhibited pre-adipocyte differentiation. Conversely, Mito-Esc failed to regulate pre-adipocyte differentiation under AMPK/SIRT1 depleted conditions. In parallel, Mito-Esc administration ameliorated HFD-induced steatosis, fibrosis of the liver, and NAFLD-associated atheromatous plaque formation in the aorta. Importantly, Mito-Esc administration inhibited HFD-induced infiltration of macrophages, a marker of steatohepatitis, in the adipose and liver tissues. The results of the in vitro studies showed that Mito-Esc treatment significantly inhibits TGF-β-induced hepatic stellate cell differentiation as well as the fibrotic markers. Consistent with the above observations, Mito-Esc treatment by activating the AMPK-SIRT1 pathway markedly reversed palmitate-induced mitochondrial superoxide production, depolarization of mitochondrial membrane potential, and lipid accumulation in HepG2 cells. Together, the therapeutic efficacy of Mito-Esc in the mitigation of HFD-induced lipotoxicity, and the associated NASH is in part, mediated by potentiating the AMPK-SIRT1 axis.

CircMAPK9 promotes adipogenesis through modulating hsa-miR-1322/FTO axis in obesity

Circular RNA (circRNA) is a special category of non-coding RNA that has garnered increasing attention in the exploration of lipid metabolism. However, the functional regulation mechanisms of circRNAs in obesity diseases remain unclear. By whole transcriptome sequencing, a total of 164 circular RNAs were found to exhibit differential expression between lean and obese individuals. RT-qPCR was used to detect significant expression of circMAPK9 in obese individuals, and it was closely related to BMI. Western blot, triglyceride detection, and Oil Red O staining were employed to investigate the role of circMAPK9/hsa-miR-1322/FTO in adipogenesis. In adipocytes, the connection between hsa-miR-1322 and circMAPK9 was verified using fluorescence in situ hybridization, luciferase reporter assay, and RNA immunoprecipitation. It was found that circMAPK9 competed for binding hsa-miR-1322 in the cytoplasm, weakening the inhibitory effect on FTO and promoting adipogenesis. Our study revealed the regulatory mechanism and important role of circMAPK9 in the process of adipogenesis.

Insights into the role of N6-methyladenosine in ferroptosis

N6-methyladenosine (m6A) methylation modification is one of the most prevalent epigenetic modifications of eukaryotic RNA. m6A methylation is widely associated with many biological processes through the modification of RNA metabolism and is associated with multiple disease states. As a newly discovered regulatory cell death in recent years, ferroptosis is an iron-dependent cell death characterized by excessive lipid peroxidation. Emerging evidence supports that ferroptosis has a significant role in the progression of diverse diseases. Besides, the key regulators of ferroptosis exhibit aberrant m6A levels under different pathological conditions. However, the correlation between m6A-modified ferroptosis and multiple diseases has not been well elucidated. In this review, we summarized the functions of m6A in ferroptosis, which are associated with the initiation and progression of multiple diseases. Investigating the role of m6A in ferroptosis might both facilitate a better understanding of the pathogenesis of these diseases and provide new opportunities for targeted treatment.

Cool executive functions and their association with body mass & fatness and the FTO gene in school-aged children

The FTO gene rs9936909 polymorphism is one of the well-documented single nucleotide polymorphisms in the context of increased risk of obesity, including in children. Few studies have tested the association of the FTO gene with cognitive functions. Deficits of "cool" executive functions (EFs) are considered a potential risk factor for excessive weight. The aims of our study were to investigate whether cool EFs are associated with the Body Mass Index, the Fat Mass Index and the risk of excess body mass and overfatness in neurotypically school-aged children, and whether the FTO gene polymorphism is involved in development of this possible association. The sample consisted of 553 children aged 6-12 years old. A body composition analysis, a neuropsychological assessment of EFs, and FTO polymorphism genotyping were performed in the children studied. The study found a significant association of an interference effect in theStroop Color-Word Interference Task and the risk of excessive body fatness, but not excessive body mass. There were no explicit associations between the FTO genotype and EFs deficits. Environmental factors, and particularly low maternal education, appeared to be the strongest contributors to the increased risk of obesity.

Metformin alleviates the cognitive impairment induced by benzo[a]pyrene via glucolipid metabolism regulated by FTO/FoxO6 pathway in mice

Benzo[a]pyrene (B[a]P) is neurotoxic; however, the mechanism and prevention are still unclear. In this study, we assessed the intervention effect of metformin (MET) on cognitive dysfunction in mice induced by B[a]P from the perspective of glucolipid metabolism. Forty-two male healthy ICR mice were randomly categorized into 6 groups and were gavaged with B[a]P (0, 2.5, 5, or 10 mg/kg), 45 times for 90 days. The controls were gavaged with edible peanut oil, and the intervention groups were co-treated with B[a]P (10 mg/kg) and MET (200 or 300 mg/kg). We assessed the cognitive function of mice, observed the pathomorphological and ultrastructural changes, and detected neuronal apoptosis and glucolipid metabolism. Results showed that B[a]P dose-dependently induced cognitive impairment, neuronal damage, glucolipid metabolism disorder in mice, and enhanced proteins of fat mass and obesity-associated protein (FTO) and forkhead box protein O6 (FoxO6) in the cerebral cortex and liver, which were alleviated by the MET intervention. The findings indicated the critical role of glucolipid metabolism disorder in the cognitive impairment in mice caused by B[a]P and the prevention of MET against B[a]P neurotoxicity by regulating glucolipid metabolism via restraining FTO/FoxO6 pathway. The finding provides a scientific basis for the neurotoxicity and prevention strategies of B[a]P.

Causal effect of adiposity on the risk of 19 gastrointestinal diseases: a Mendelian randomization study

OBJECTIVE

Although the association between adiposity and gastrointestinal (GI) diseases has been explored, the causal effects of adiposity on GI diseases are largely unknown.

METHODS

Mendelian randomization was conducted using single-nucleotide polymorphisms associated with BMI and waist circumference (WC) as instrumental variables, and the causal associations of BMI or WC with GI conditions were estimated among >400,000 UK Biobank participants, >170,000 Finnish-descent participants, and numerous consortia participants of predominantly European ancestry.

RESULTS

Genetically predicted BMI was robustly associated with increased risk of nonalcoholic fatty liver disease (NAFLD), cholecystitis, cholelithiasis, and primary biliary cholangitis. For the diseases, the odds ratio per 1-SD increase in genetically predicted BMI (4.77 kg/m2 ) ranged from 1.22 (95% CI: 1.12-1.34; p < 0.0001) for NAFLD to 1.65 (95% CI: 1.31-2.06; p < 0.0001) for cholecystitis. Genetically predicted WC was robustly associated with increased risk of NAFLD, alcoholic liver disease, cholecystitis, cholelithiasis, colon cancer, and gastric cancer. Alcoholic liver disease was consistently associated with WC even after adjusting for alcohol consumption in a multivariable Mendelian randomization analysis. The odds ratio per 1-SD increase in genetically predicted WC (12.52 cm) for such associations ranged from 1.41 (95% CI: 1.17-1.70; p = 0.0015) for gastric cancer to 1.74 (95% CI: 1.21-1.78; p < 0.0001) for cholelithiasis.

CONCLUSIONS

High genetically predicted adiposity was causally associated with an increased risk of GI abnormalities, particularly of hepatobiliary organs (liver, biliary tract, and gallbladder) that are functionally related to fat metabolism.

Associations of genetic markers of diabetes mellitus with carotid atherosclerosis: a community-based case-control study

BACKGROUND

Diabetes mellitus (DM) is a well-established determinant of atherosclerosis and cardiovascular diseases (CVD). Recently, genome-wide association studies (GWAS) identified several single nucleotide polymorphism (SNP) significantly correlated with DM. The study aimed to explore the relationships of the top significant DM SNPs with carotid atherosclerosis (CA).

METHODS

We used a case-control design and randomly selected 309 cases and 439 controls with and without, respectively, carotid plaque (CP) from a community-based cohort. Eight recent GWAS on DM in East Asians reported hundreds of SNPs with genome-wide significance. The study used the top significant DM SNPs, with a p-value < 10^-16, as the candidate genetic markers of CA. The independent effects of these DM SNPs on CA were assessed by multivariable logistic regression analyses to control the effects of conventional cardio-metabolic risk factors.

RESULTS

Multivariable analyses showed that, 9 SNPs, including rs4712524, rs1150777, rs10842993, rs2858980, rs9583907, rs1077476, rs7180016, rs4383154, and rs9937354, showed promising associations with the presence of carotid plaque (CP). Among them, rs9937354, rs10842993, rs7180016, and rs4383154 showed significantly independent effects. The means (SD) of the 9-locus genetic risk score (9-GRS) of CP-positive and -negative subjects were 9.19 (1.53) and 8.62 (1.63), respectively (p < 0.001). The corresponding values of 4-locus GRS (4-GRS) were 4.02 (0.81) and. 3.78 (0.92), respectively (p < 0.001). The multivariable-adjusted odds ratio of having CP for per 1.0 increase in 9-GRS and 4-GRS were 1.30 (95% CI 1.18-1.44; p = 4.7 × 10^-7) and 1.47 (95% CI 1.74-9.40; p = 6.1 × 10^-5), respectively. The means of multi-locus GRSs of DM patients were similar to those of CP-positive subjects and higher than those of CP-negative or DM-negative subjects.

CONCLUSIONS

We identified 9 DM SNPs showing promising associations with CP. The multi-locus GRSs may be used as biomarkers for the identification and prediction of high-risks subjects for atherosclerosis and atherosclerotic diseases. Future studies on these specific SNPs and their associated genes may provide valuable information for the preventions of DM and atherosclerosis.

Interactive effects of FTO rs9939609 and obesogenic behavioral factors on adiposity-related anthropometric and metabolic phenotypes

Numerous genetic variants have been linked to obesity predisposition, however, the interplay of genetic and behavioral factors is very crucial in determining the final phenotype. Therefore, this study examined the interactive effects of the FTO rs9939609 and various obesogenic behavioral factors on adiposity-related anthropometric and metabolic phenotypes in a sample of Pakistani population. A total of 612 participants encompassing 306 overweight/obese (cases) and an equal number (306) of age- and sex-matched normal-weight (controls) individuals were included in the study. Adiposity-related anthropometric parameters were collected by taking corresponding body measurements by following standard procedures. The metabolic parameters were assessed by performing corresponding biochemical assays. A standard questionnaire was devised for the collection of adiposity-related behavioral information. The FTO rs9939609 was genotyped by employing TaqMan allelic discrimination assay. The data was analyzed by using SPSS software. Interactive effects of the FTO rs9939609 and behavioral factors on obesity-related anthropometric and metabolic phenotypes were examined via linear regression by adjusting potential confounders and making correction for multiple comparisons. The results implied that the interaction between the FTO rs9939609 and low physical activity may significantly increase various adiposity-related anthropometric variables (p < 0.05). However, no such interactive effects were found on any adiposity-related metabolic variable. In conclusion, the interaction between the FTO rs9939609 and low physical activity may have a significant impact on obesity-related anthropometric traits in the Pakistani population.

Roles of RNA m6A modification in nonalcoholic fatty liver disease

NAFLD is a series of liver disorders, and it has become the most prevalent hepatic disease to date. However, there are no approved and effective pharmaceuticals for NAFLD owing to a poor understanding of its pathological mechanisms. While emerging studies have demonstrated that m6A modification is highly associated with NAFLD. In this review, we summarize the general profile of NAFLD and m6A modification, and the role of m6A regulators including erasers, writers, and readers in NAFLD. Finally, we also highlight the clinical significance of m6A in NAFLD.

Transient regulation of RNA methylation in human hematopoietic stem cells promotes their homing and engraftment

Enhancing the efficiency of hematopoietic stem cell (HSC) homing and engraftment is critical for cord blood (CB) hematopoietic cell transplantation (HCT). Recent studies indicate that N6-methyladenosine (m6A) modulates the expression of mRNAs that are critical for stem cell function by influencing their stability. Here, we demonstrate that inhibition of RNA decay by regulation of RNA methylation, enhances the expression of the homing receptor chemokine C-X-C receptor-4 (CXCR4) in HSCs. We show that YTH N6-methyladenosine RNA binding protein 2 (YTHDF2), a m6A reader and FTO α-ketoglutarate dependent dioxygenase (FTO), a m6A eraser play an opposite role in this process. Through screening, we identified several FDA-approved compounds that regulate the expression of YTHDF2 and FTO in CB CD34+ cells. We show that transient downregulation of YTHDF2 or activation of FTO by using these compounds inhibits CXCR4 decay in CB HSCs and promotes their homing and engraftment. Our results demonstrate a novel regulation strategy to enhance the function of CB HSCs and provide a translational approach to enhance the clinical efficacy of HCT.

What do we know about nutrient-based strategies targeting molecular mechanisms associated with obesity-related fatty liver disease?

Obesity is a risk factor for developing nonalcoholic fatty liver disease (NAFLD), and the associated molecular mechanisms could be targeted with nutrient-based strategies. Therefore, it is necessary to review the current mechanisms to propose further treatments. Obesity facilitates the onset of insulin resistance, lipidic abnormalities, hepatic fat accumulation, lipid peroxidation, mitochondrial dysfunction, excessive reactive oxygen species (ROS) production, and inflammation, all related to further steatosis progression and fibrosis. Microbiota alterations can also influence liver disease by the translocation of pathogenic bacteria, energy extraction from short chain fatty acids (SCFAs), intestinal suppression of the expression of fasting-induced adipose factor (FIAF), reduction of bile acids, and altered choline metabolism. There are also genetic polymorphisms in metabolic proteins that predispose to a higher risk of liver diseases, such as those found in the patatin-like phospholipase domain-containing 3 (PNPLA3), transmembrane 6 superfamily member 2 (TM6SF2), membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) or also known as lysophosphatidylinositol acyltransferase 1 (LPIAT1), transmembrane channel-like 4 genes (TMC4), fat mass and obesity-associated protein (FTO), the b Klotho (KLB) and carboxylesterase (CES1). No clear dietary guidelines target all mechanisms related to NAFLD development and progression. However, energy and carbohydrate intake restriction, regular physical exercise, supplementation of antioxidants, and restoration of gut microbiota seem to have beneficial effects on the new proposed features of NAFLD.

Unique genetic variants of lean nonalcoholic fatty liver disease: a retrospective cohort study

We investigated the prevalence and clinical metabolic characteristics of lean nonalcoholic fatty liver disease (NAFLD) in an elderly Chinese population and assessed the relevance of lipid markers and genetic variation. All 5,338 community subjects underwent detailed clinical and laboratory examinations and were divided into three groups: lean (Body mass index (BMI) < 23 kg/m², n = 2,012), overweight (BMI = 23-24.9 kg/m², n = 1,354), and obese (BMI ≥ 25 kg/m², n = 1,972). Single nucleotide polymorphisms were selected based on those reported in previous NAFLD or obesity genome-wide association studies. The frequencies of alleles and genotypes were calculated and statistically analyzed with Pearson's χ² tests. One-way ANCOVA was used to test the association between positive SNPs and metabolic parameters in lean NAFLD individuals. Our results showed that the C allele frequency of rs2279026, the G allele of rs2279028, the C allele of rs780093, and the C allele frequency of rs1260326 were higher in obese NAFLD than in lean NAFLD (P < 0.05). In addition, we observed an association between the CC of rs1421085, TT of rs3751812, AA of rs8050136, and AA of rs9939609 genotypes in the FTO gene and low-density lipoprotein levels (P < 0.05). In conclusion, our findings provide a unique perspective on the prevalence, genetic characteristics, and metabolic profile of NAFLD in older lean individuals in China. This is the first study to examine the association between genetic variants in the FTO, TFAP2B and GCKR genes and NAFLD in a cohort of lean individuals.

Genetics, genomics, and diet interactions in obesity in the Latin American environment

Obesity is a chronic disease characterized by abnormal or excessive fat accumulation that could impact an individual's health; moreover, the World Health Organization (WHO) has declared obesity a global epidemic since 1997. In Latin America, in 2016, reports indicated that 24.2% of the adult population was obese. The environmental factor or specific behaviors like dietary intake or physical activity have a vital role in the development of a condition like obesity, but the interaction of genes could contribute to that predisposition. Hence, it is vital to understand the relationship between genes and disease. Indeed, genetics in nutrition studies the genetic variations and their effect on dietary response; while genomics in nutrition studies the role of nutrients in gene expression. The present review represents a compendium of the dietary behaviors in the Latin American environment and the interactions of genes with their single nucleotide polymorphisms (SNPs) associated with obesity, including the risk allele frequencies in the Latin American population. Additionally, a bibliographical selection of several studies has been included; these studies examined the impact that dietary patterns in Latin American environments have on the expression of numerous genes involved in obesity-associated metabolic pathways.

Buyang Huanwu decoction affects gut microbiota and lipid metabolism in a ZDF rat model of co-morbid type 2 diabetes mellitus and obesity: An integrated metabolomics analysis

Type 2 diabetes mellitus (T2DM) is a chronic disease associated with many severe complications such as blindness, amputation, renal failure, and cardiovascular disease. Currently, the prevention and treatment of T2DM is a major global challenge as the number of aging and obese people is increasing. Traditional Chinese medicine offers the advantages of multi-target holistic and individual treatment for obesity and type 2 diabetes. However, most of the TCMs for T2DM are not scientifically evaluated. Here, Buyang Huanwu decoction (BYHWD), a widely used TCM formula, was used to explore scientific pharmacological activity against T2DM in rat models. First, BYHWD exhibited excellent inhibitory actions against body fat accumulation and increased blood triglyceride levels, and a high-fat diet (HFD) induced blood glucose elevation in diabetic rats. Moreover, 16S rDNA sequencing of fecal samples identified the distinct changes in the community composition of gut flora following BYHWD treatment, displayed as significantly increased Bacteroidetes and dramatically decreased Firmicutes at the phyla level, and the remarkable increase in the abundance of Lactobacillus and Blautia. Additionally, lipid metabolomics based on liquid chromatography-mass spectrometry revealed a significant shift of lipid metabolites in the liver after BYHWD treatment. Notably, these differential lipid metabolites were particularly involved in biological processes such as cholesterol metabolism, linoleic acid metabolism, glycerolipid metabolism, glycerophospholipid metabolism, insulin resistance, arachidonic acid metabolism, and alpha-linoleic acid metabolism. Importantly, Spearman correlation analyses suggested an association between disturbed gut microbiota and altered lipid metabolites. Moreover, they were also closely associated with the bioactivities of BYHWD to reduce the blood lipid and blood glucose levels. Collectively, these results suggest that BYHWD could meliorate gut microbiota dysbiosis and lipid metabolite alterations induced by the HFD in diabetic rats. These results not only provide a novel perspective on understanding the mechanisms underlying BYHWD bioactivity against T2DM but also suggest the use of advanced systems biology methods to reveal some unknown scientific laws in TCM theories.

Racial Disparities in Methylation of NRF1, FTO, and LEPR Gene in Childhood Obesity

Childhood obesity has affected the health of millions of children around the world despite vigorous efforts by health experts. The obesity epidemic in the United States has disproportionately afflicted certain racial and ethnic minority groups. African American children are more likely than other children to have obesity-related risk factors such as hyperlipidemia, diabetes, cardiovascular disease, and coronavirus disease (COVID-19). For the reduction in obesity-related health inequalities to be successful, it is essential to identify the variables affecting various groups. A notable advancement in epigenetic biology has been made over the past decade. Epigenetic changes like DNA methylation impact on many genes associated with obesity. Here, we evaluated the DNA methylation levels of the genes NRF1, FTO, and LEPR from the saliva of children using real-time quantitative PCR-based multiplex MethyLight technology. ALU was used as a reference gene, and the Percent of Methylated Reference (PMR) was calculated for each sample. European American children showed a significant increase in PMR of NRF1 and FTO in overweight/obese participants compared to normal weight, but not in African American children. After adjusting for maternal education and annual family income by regression analysis, the PMR of NRF1 and FTO was significantly associated with BMI z-score only in European American children. While for the gene LEPR, African American children had higher methylation in normal weight participants as compared to overweight/obese and no methylation difference in European American children. The PMR of LEPR was significantly negative associated with the obesity measures only in African American children. These findings contribute to a race-specific link between NRF1, FTO, and LEPR gene methylation and childhood obesity.

FTO promotes liver inflammation by suppressing m6A mRNA methylation of IL-17RA

Background

Previous studies have demonstrated that inflammation-related interleukin-17 (IL-17) signaling plays a pivotal role in the pathogenesis of non-alcoholic steatohepatitis (NASH)- and alcoholic liver disease (ALD)-induced hepatocellular carcinoma (HCC). However, rare efforts have been intended at implementing the analysis of N6-methyladenosine (m6A) mRNA methylation to elucidate the underpinning function of the IL-17 receptor A (IL-17RA) during the inflammation-carcinogenesis transformation of HCC.

Methods

We performed methylated RNA immunoprecipitation sequencing (MeRIP-seq) using normal, HCC tumor and paired tumor adjacent tissues from patients to investigate the dynamic changes of m6A mRNA methylation in the process of HCC. Additionally, murine non-alcoholic fatty liver disease (NAFLD) model and murine chronic liver injury model were utilized to investigate the role of IL-17RA regulated by m6A mRNA modulator fat mass and obesity-associated (FTO) in chronic hepatic inflammation.

Results

MeRIP-seq revealed the reduction of m6A mRNA methylation of IL-17RA in tumor adjacent tissues with chronic inflammation, suggesting the potential role of IL-17RA in the inflammation-carcinogenesis transformation of HCC. Besides, we demonstrated that FTO, rather than methyltransferase-like 3 (METTL3), methyltransferase-like 14 (METTL14), and alkB homolog 5 (ALKBH5) functions as a main modulator for the decrease of m6A mRNA methylation of IL-17RA via knockdown and overexpression of FTO in vitro and in vivo.

Conclusions

Overall, we elaborated the underlying mechanisms of the increase of IL-17RA resulting in chronic inflammation via the demethylation of FTO in tumor adjacent tissues and demonstrated that targeting the specific m6A modulator FTO may provide an effective treatment for hepatitis patients to prevent the development of HCC.

Risk Factors from Pregnancy to Adulthood in Multiple Sclerosis Outcome

Multiple sclerosis (MS) is an autoimmune disease characterized by a robust inflammatory response against myelin sheath antigens, which causes astrocyte and microglial activation and demyelination of the central nervous system (CNS). Multiple genetic predispositions and environmental factors are known to influence the immune response in autoimmune diseases, such as MS, and in the experimental autoimmune encephalomyelitis (EAE) model. Although the predisposition to suffer from MS seems to be a multifactorial process, a highly sensitive period is pregnancy due to factors that alter the development and differentiation of the CNS and the immune system, which increases the offspring’s susceptibility to develop MS. In this regard, there is evidence that thyroid hormone deficiency during gestation, such as hypothyroidism or hypothyroxinemia, may increase susceptibility to autoimmune diseases such as MS. In this review, we discuss the relevance of the gestational period for the development of MS in adulthood.

Association of FTO gene variant rs9939609 with hyperandrogenemia and fasting glucose levels in South Indian women with polycystic ovarian syndrome

Background

Polycystic ovary syndrome (PCOS) is a common endocrine–metabolic disorder due to genetic and environmental factors. Genetic variants located in intron 1 of Fat mass and obesity-associated (FTO) gene are associated with increased risk of obesity and metabolic disorders. This study aims to investigate the association of common FTO polymorphism rs9939609 in South Indian women with PCOS to assess its association with metabolic and endocrine parameters. FTO genotyping was done on 100 PCOS patients and 70 controls by Sanger sequencing.

Results

The distribution of rs9939609 was observed between groups (28% TT, 57% TA, and 15% AA for PCOS and 37.1% TT, 51.4% TA, and 11.4% AA for the controls). In the PCOS group, across the carriers of different genotypes, a significant association was found between body mass index (BMI), fasting glucose levels, and testosterone with the presence of at least one risk allele of FTO rs9939609. Logistic regression analysis showed the association of fasting glucose levels and testosterone (OR 1.30 [1.03–1.63] and OR 5.83 [1.61–21.11], respectively) with FTO rs9939609.

Conclusions

Our findings indicated that FTO SNP rs9939609 was not associated with PCOS, but suggested a significant association of rs9939609 with hyperandrogenemia, fasting glucose levels, and BMI in South Indian women with PCOS.

Demethylase FTO promotes mechanical stress induced osteogenic differentiation of BMSCs with up-regulation of HIF-1α

BACKGROUND

In orthodontics, mechanical stress plays an important role in the process of bone remodeling. Mechanical stress has an effect on osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). However, the mechanism remains to be studied. The aim of this study is to investigate the effects of demethyltransferase fat mass and obesity-associated (FTO) on osteogenic differentiation of BMSCs under mechanical stress condition.

METHODS AND RESULTS

The rat BMSCs were cultured in vitro, followed by flow cytometry to identify the cell surface antigens. Osteogenic differentiation of BMSCs was induced by mechanical stress by using the flexcell tension system for 6 h every day and 3 days in total. BMSCs were transfected by using plasmid for FTO knockdown. The expression level of FTO, hypoxia-inducible factor (HIF)-1α, runt-related transcription factor 2 (RUNX2), bone morphogenetic proteins (BMPs) and alkaline phosphatase (ALP) were measured by real-time qPCR, western blotting. ALP activity were determined by ALP staining assays. The expression of FTO and HIF-1α in BMSCs with mechanical stress were significantly higher than BMSCs without mechanical stress, also, the expression of osteogenic differentiation markers were higher in BMSCs with mechanical stress. Knockdown of FTO decreased expression of osteogenic differentiation marker and ALP activity in stretched BMSCs. In addition, the expression of HIF-1α was decreased after knocking down FTO.

CONCLUSIONS

FTO promotes the expression of HIF-1α and osteogenic differentiation under the condition of mechanical stress. This finding may facilitate the clinical application of orthodontics and the mechanism research of mechanical stress-induced osteogenesis.

Ramadan Diurnal Intermittent Fasting Is Associated With Attenuated FTO Gene Expression in Subjects With Overweight and Obesity: A Prospective Cohort Study

Aim and Background

A growing body of evidence supports the impact of intermittent fasting (IF) on normalizing body weight and that the interaction between body genes and environmental factors shapes human susceptibility to developing obesity. FTO gene is one of these genes with metabolic effects related to energy metabolism and body fat deposition. This research examined the changes in FTO gene expression upon Ramadan intermittent fasting (RIF) in a group of metabolically healthy subjects with overweight and obesity.

Methods

Sixty-three (63) subjects were recruited, of which 57 (17 males and 40 females, mean age 38.4 ± 11.2 years) subjects with overweight and obesity (BMI = 29.89 ± 5.02 kg/m2were recruited and monitored before and at the end of Ramadan month), and 6 healthy subjects with normal BMI (21.4 ± 2.20 kg/m2) recruited only to standardize the reference for normal levels of FTO gene expression. In the two-time points, anthropometric, biochemical, and dietary assessments were undertaken, and FTO gene expression tests were performed using RNA extracted from the whole blood sample.

Results

In contrast to normal BMI subjects, the relative gene expressions in overweight/obese were significantly decreased at the end of Ramadan (-32.30%, 95% CI-0.052 -0.981) in comparison with the pre-fasting state. Significant reductions were found in body weight, BMI, fat mass, body fat percent, hip circumference, LDL, IL-6, TNF-α (P<0.001), and in waist circumference (P<0.05), whilst HDL and IL-10 significantly increased (P<0.001) at the end of Ramadan in comparison with the pre-fasting levels. Binary logistic regression analysis for genetic expressions showed no significant association between high-energy intake, waist circumference, or obesity and FTO gene expression.

Conclusions

RIF is associated with the downregulation of the FTO gene expression in subjects with obesity, and this may explain, at least in part, its favorable metabolic effects. Hence, RIF presumably may entail a protective impact against body weight gain and its adverse metabolic-related derangements in subjects with obesity.

The Antarctic Weddell seal genome reveals evidence of selection on cardiovascular phenotype and lipid handling

The Weddell seal (Leptonychotes weddellii) thrives in its extreme Antarctic environment. We generated the Weddell seal genome assembly and a high-quality annotation to investigate genome-wide evolutionary pressures that underlie its phenotype and to study genes implicated in hypoxia tolerance and a lipid-based metabolism. Genome-wide analyses included gene family expansion/contraction, positive selection, and diverged sequence (acceleration) compared to other placental mammals, identifying selection in coding and non-coding sequence in five pathways that may shape cardiovascular phenotype. Lipid metabolism as well as hypoxia genes contained more accelerated regions in the Weddell seal compared to genomic background. Top-significant genes were SUMO2 and EP300; both regulate hypoxia inducible factor signaling. Liver expression of four genes with the strongest acceleration signals differ between Weddell seals and a terrestrial mammal, sheep. We also report a high-density lipoprotein-like particle in Weddell seal serum not present in other mammals, including the shallow-diving harbor seal.

Insights into N6-methyladenosine and programmed cell death in cancer

N6-methyladenosine (m6A) methylation, the most common form of internal RNA modification in eukaryotes, has gained increasing attention and become a hot research topic in recent years. M6A plays multifunctional roles in normal and abnormal biological processes, and its role may vary greatly depending on the position of the m6A motif. Programmed cell death (PCD) includes apoptosis, autophagy, pyroptosis, necroptosis and ferroptosis, most of which involve the breakdown of the plasma membrane. Based on the implications of m6A methylation on PCD, the regulators and functional roles of m6A methylation were comprehensively studied and reported. In this review, we focus on the high-complexity links between m6A and different types of PCD pathways, which are then closely associated with the initiation, progression and resistance of cancer. Herein, clarifying the relationship between m6A and PCD is of great significance to provide novel strategies for cancer treatment, and has a great potential prospect of clinical application.

Metabolic Syndrome: Updates on Pathophysiology and Management in 2021

Metabolic syndrome (MetS) forms a cluster of metabolic dysregulations including insulin resistance, atherogenic dyslipidemia, central obesity, and hypertension. The pathogenesis of MetS encompasses multiple genetic and acquired entities that fall under the umbrella of insulin resistance and chronic low-grade inflammation. If left untreated, MetS is significantly associated with an increased risk of developing diabetes and cardiovascular diseases (CVDs). Given that CVDs constitute by far the leading cause of morbidity and mortality worldwide, it has become essential to investigate the role played by MetS in this context to reduce the heavy burden of the disease. As such, and while MetS relatively constitutes a novel clinical entity, the extent of research about the disease has been exponentially growing in the past few decades. However, many aspects of this clinical entity are still not completely understood, and many questions remain unanswered to date. In this review, we provide a historical background and highlight the epidemiology of MetS. We also discuss the current and latest knowledge about the histopathology and pathophysiology of the disease. Finally, we summarize the most recent updates about the management and the prevention of this clinical syndrome.

Critical roles of FTO-mediated mRNA m6A demethylation in regulating adipogenesis and lipid metabolism: Implications in lipid metabolic disorders

The goal this review is to clarify the effects of the fat mass and obesity-associated protein (FTO) in lipid metabolism regulation and related underlying mechanisms through the FTO-mediated demethylation of m⁶A modification. FTO catalyzes the demethylation of m⁶A to alter the processing, maturation and translation of the mRNAs of lipid-related genes. FTO overexpression in the liver promotes lipogenesis and lipid droplet (LD) enlargement and suppresses CPT-1–mediated fatty acid oxidation via the SREBP1c pathway, promoting excessive lipid storage and nonalcoholic fatty liver diseases (NAFLD). FTO enhances preadipocyte differentiation through the C/EBPβ pathway, and facilitates adipogenesis and fat deposition by altering the alternative splicing of RUNX1T1, the expression of PPARγ and ANGPTL4, and the phosphorylation of PLIN1, whereas it inhibits lipolysis by inhibiting IRX3 expression and the leptin pathway, causing the occurrence and development of obesity. Suppression of the PPARβ/δ and AMPK pathways by FTO-mediated m⁶A demethylation damages lipid utilization in skeletal muscles, leading to the occurrence of diabetic hyperlipidemia. m⁶A demethylation by FTO inhibits macrophage lipid influx by downregulating PPARγ protein expression and accelerates cholesterol efflux by phosphorylating AMPK, thereby impeding foam cell formation and atherosclerosis development. In summary, FTO-mediated m⁶A demethylation modulates the expression of lipid-related genes to regulate lipid metabolism and lipid disorder diseases.

Deciphering Obesity-Related Gene Clusters Unearths SOCS3 Immune Infiltrates and 5mC/m6A Modifiers in Ossification of Ligamentum Flavum Pathogenesis

BACKGROUND

Ossification of ligamentum flavum (OLF) is an insidious and debilitating heterotopic ossifying disease with etiological heterogeneity and undefined pathogenesis. Obese individuals predispose to OLF, whereas the underlying connections between obesity phenotype and OLF pathomechanism are not fully understood. Therefore, this study aims to explore distinct obesity-related genes and their functional signatures in OLF.

METHODS

The transcriptome sequencing data related to OLF were downloaded from the GSE106253 in the Gene Expression Omnibus (GEO) database. The obesity-related differentially expressed genes (ORDEGs) in OLF were screened, and functional and pathway enrichment analysis were applied for these genes. Furthermore, protein-protein interactions (PPI), module analysis, transcription factor enrichment analysis (TFEA), and experiment validation were used to identify hub ORDEGs. The immune infiltration landscape in OLF was depicted, and correlation analysis between core gene SOCS3 and OLF-related infiltrating immune cells (OIICs) as well as 5mC/m6A modifiers in OLF was constructed.

RESULTS

Ninety-nine ORDEGs were preliminarily identified, and functional annotations showed these genes were mainly involved in metabolism, inflammation, and immune-related biological functions and pathways. Integrative bioinformatic algorithms determined a crucial gene cluster associated with inflammatory/immune responses, such as TNF signaling pathway, JAK-STAT signaling pathway, and regulation of interferon-gamma-mediated signaling. Eight hub ORDEGs were validated, including 6 down-regulated genes (SOCS3, PPARG, ICAM-1, CCL2, MYC, and NT5E) and 2 up-regulated genes (PTGS2 and VEGFA). Furthermore, 14 differential OIICs were identified by ssGSEA and xCell, and SOCS3 was overlapped to be the core gene, which was associated with multiple immune infiltrates (dendritic cells, macrophage, and T cells) and six m6A modifiers as well as four 5mC regulators in OLF. Reduced SOCS3 and FTO expression and up-regulated DNMT1 level in OLF were validated by Western blotting.

CONCLUSION

This study deciphered immune/inflammatory signatures of obesity-related gene clusters for the first time, and defined SOCS3 as one core gene. The crosstalk between 5mC/m6A methylation may be a key mediator of SOCS3 expression and immune infiltration. These findings will provide more insights into molecular mechanisms and therapeutic targets of obesity-related OLF.

The Lipid Profiles in Different Characteristics of Women with PCOS and the Interaction Between Dyslipidemia and Metabolic Disorder States: A Retrospective Study in Chinese Population

PURPOSE

To exhibit the lipid profiles in PCOS women with different characteristics and to access correlations between alternation of key lipid parameters and characteristics of PCOS.

DESIGN

A retrospective study.

PARTICIPANTS

A total of 700 PCOS women were included.

METHODS

Retrospective study on 700 women (age 24.6 ± 4.7 years), diagnosed with PCOS in the outpatient department of Obstetrics and Gynecology Hospital of Fudan University according to Rotterdam criteria. Anthropometric features, hormone levels, lipid levels, and metabolic parameters were measured and compared between PCOS patients with different characteristics.

RESULTS

There was a high prevalence of dyslipidemia among Chinese PCOS patients (41.3%), and the most common pattern was low HDL. Patients with clinical hyperandrogenism presented with significantly decreased HDL and Apo-A levels. The levels of TG, LDL, Apo-B, TG/HDL, and Apo-B/Apo-A were significantly increased in the insulin resistance subgroup. The levels of TC and TG were significantly increased in the dysglycemia and T2DM women. And in general, the levels of TG, and Apo-B had an increasing trend with BMI. Moreover, AI, TG/HDL, and Apo-B/Apo-A ratios were associated with some characteristics of PCOS, such as insulin resistance, and obesity.

CONCLUSION

The PCOS women with different characteristics presented with different lipid profiles, and there is a complex correlation between lipid metabolism and PCOS characteristics, which may explain the increased risk of long-term cardiovascular disease. Regular screening of blood lipids is essential for PCOS women. Identification of optimal subgroups in PCOS patients that need lipid-lowering treatment and therapeutic effectiveness is worth exploring.

Association of ADIPOQ-rs2241766 and FTO-rs9939609 genetic variants with body mass index trajectory in women of reproductive age over 6 years of follow-up: the PREDI study

BACKGROUND

Interindividual variations in body mass index (BMI) can be partially explained by genetic differences. We aimed to examine the association of the ADIPOQ-rs2241766, LEP-rs7799039 and FTO-rs9939609 genetic variants with BMI trajectory in women of reproductive age over 6 years of follow-up.

METHODS

This was a prospective study that used data from 435 women of the PREDI Study conducted in Brazil. Socioeconomic, biological and anthropometric data were collected at four time points: 2012 (baseline) in the maternity hospital, and 2013-14, 2016-17 and 2018 (1^st, 2^nd and 3^rd follow-ups) at the participant's home. Genotyping was performed by PCR-RFLP. Linear mixed-effect and Poisson regression models were used to address the association of ADIPOQ, LEP and FTO genotypes with BMI and overweight/obesity status.

RESULTS

Women carrying the risk allele (TA or AA) of the FTO-rs9939609 genetic variant had a 1.16 kg/m² higher BMI over the follow-up period than those carrying the wild-type genotype (TT), even when adjusted for potential confounders (95% CI: 0.23-2.10, p = 0.015). The risk of obesity associated with the FTO-TA or AA genotype decreased over the years, demonstrating an influence of time on its trajectory (IRR = 0.99, 95% CI: 0.98-0.99, p = 0.016). There was no variation in BMI trajectories for the ADIPOQ-rs2241766, LEP-rs7799039 or FTO-rs9939609 genetic variant.

CONCLUSIONS

The results of this study suggest that monitoring women of reproductive age with ADIPOQ-rs2241766 TG/GG or FTO-rs9939609 TA/AA genotypes may be an important strategy to reduce maternal excess body weight and, consequently, the long-term public health burden of obesity.

The role of RNA m6A methylation in lipid metabolism

The m6A methylation is the most numerous modification of mRNA in mammals, coordinated by RNA m6A methyltransferases, RNA m6A demethylases, and RNA m6A binding proteins. They change the RNA m6A methylation level in their specific manner. RNA m6A modification has a significant impact on lipid metabolic regulation. The "writer" METTL3/METTL14 and the "eraser" FTO can promote the accumulation of lipids in various cells by affecting the decomposition and synthesis of lipids. The "reader" YTHDF recognizes m6A methylation sites of RNA and regulates the target genes' translation. Due to this function that regulates lipid metabolism, RNA m6A methylation plays a pivotal role in metabolic diseases and makes it a great potential target for therapy.

GR-mediated transcriptional regulation of m6A metabolic genes contributes to diet-induced fatty liver in hens

Background

Glucocorticoid receptor (GR) mediated corticosterone-induced fatty liver syndrome (FLS) in the chicken by transactivation of Fat mass and obesity associated gene (FTO), leading to demethylation of N6-methyladenosine (m⁶A) and post-transcriptional activation of lipogenic genes. Nutrition is considered the main cause of FLS in the modern poultry industry. Therefore, this study was aimed to investigate whether GR and m⁶A modification are involved in high-energy and low protein (HELP) diet-induced FLS in laying hens, and if true, what specific m⁶A sites of lipogenic genes are modified and how GR mediates m⁶A-dependent lipogenic gene activation in HELP diet-induced FLS in the chicken.

Results

Laying hens fed HELP diet exhibit excess (P < 0.05) lipid accumulation and lipogenic genes activation in the liver, which is associated with significantly increased (P < 0.05) GR expression that coincided with global m⁶A demethylation. Concurrently, the m⁶A demethylase FTO is upregulated (P < 0.05), whereas the m⁶A reader YTHDF2 is downregulated (P < 0.05) in the liver of FLS chickens. Further analysis identifies site-specific demethylation (P < 0.05) of m⁶A in the mRNA of lipogenic genes, including FASN, SREBP1 and SCD. Moreover, GR binding to the promoter of FTO gene is highly enriched (P < 0.05), while GR binding to the promoter of YTHDF2 gene is diminished (P < 0.05).

Conclusions

These results implicate a possible role of GR-mediated transcriptional regulation of m⁶A metabolic genes on m⁶A-depenent post-transcriptional activation of lipogenic genes and shed new light in the molecular mechanism of FLS etiology in the chicken.

The association between FTO rs9939609 polymorphism and serum lipid profile in adult women

BACKGROUND

FTO gene is considered to play an important role in many metabolic diseases. Evidence from studies indicated the possible association between the FTO rs9939609 polymorphisms with serum lipid profile. Therefore, this study aimed to investigate the association of FTO rs9939609 polymorphism with lipid profile in Iranian women.

METHODS

This cross-sectional study was carried out on 380 adult women. Information about age, height, weight, BMI, physical activity, and dietary intake were collected. The serum levels of Low Density Lipoprotein (LDL), High Density Lipoprotein (HDL), Triglyceride (TG), and total cholesterol were measured. The FTO gene was genotyped for rs9939609 polymorphism. The participants were divided into two groups of TT and AT/AA considering dominant model of FTO rs9939609 polymorphism.

RESULTS

General characteristics of the participants with different FTO genotypes were not significantly different. The lower levels of HDL were observed in AT/AA genotypes compared to the TT wild type genotype of FTO rs9939609 polymorphism (P = 0.004). Adjustments of age, BMI, and physical activity did not change the results.

CONCLUSIONS

However, the significant association between FTO genotype and the HDL level was disappeared after further adjustments for dietary intake. Further studies are warranted to identify the underlying mechanisms of the possible association between FTO gene and serum lipid profile.

Comprehensive Analysis of N6-Methyladenosine RNA Methylation Regulators Expression Identify Distinct Molecular Subtypes of Myocardial Infarction

Background: Myocardial infarction (MI) is one of the leading threats to human health. N6-methyladenosine (m6A) modification, as a pivotal regulator of messenger RNA stability, protein expression, and cellular processes, exhibits important roles in the development of cardiac remodeling and cardiomyocyte contractile function.

Methods: The expression levels of m6A regulators were analyzed using the GSE5406 database. We analyzed genome-wide association study data and single-cell sequencing data to confirm the functional importance of m6A regulators in MI. Three molecular subtypes with different clinical characteristics were established to tailor treatment strategies for patients with MI. We applied pathway analysis and differentially expressed gene (DEG) analysis to study the changes in gene expression and identified four common DEGs. Furthermore, we constructed the protein–protein interaction network and confirmed several hub genes in three clusters of MI. To lucubrate the potential functions, we performed a ClueGO analysis of these hub networks.

Results: In this study, we identified that the levels of FTO, YTHDF3, ZC3H13, and WTAP were dramatically differently expressed in MI tissues compared with controls. Bioinformatics analysis showed that DEGs in MI were significantly related to modulating calcium signaling and chemokine signaling, and m6A regulators were related to regulating glucose measurement and elevated blood glucose levels. Furthermore, genome-wide association study data analysis showed that WTAP single-nucleotide polymorphism was significantly related to the progression of MI. In addition, single-cell sequencing found that WTAP is widely expressed in the heart tissues. Moreover, we conducted consensus clustering for MI in view of the dysregulated m6A regulators’ expression in MI. According to the expression levels, we found MI patients could be clustered into three subtypes. Pathway analysis showed the DEGs among different clusters in MI were assigned to HIF-1, IL-17, MAPK, PI3K-Akt signaling pathways, etc. The module analysis detected several genes, including BAG2, BAG3, MMP2, etc. We also found that MI-related network was significantly related to positive and negative regulation of angiogenesis and response to heat. The hub networks in MI clusters were significantly related to antigen processing and ubiquitin-mediated proteolysis, RNA splicing, and stability, indicating that these processes may contribute to the development of MI.

Conclusion: Collectively, our study could provide more information for understanding the roles of m6A in MI, which may provide a novel insight into identifying biomarkers for MI treatment and diagnosis.

Human umbilical cord-derived mesenchymal stem cell-exosomal miR-627-5p ameliorates non-alcoholic fatty liver disease by repressing FTO expression

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver disorders. Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs)-based therapy is currently considered to be an effective treatment for NAFLD. The present study aimed to determine whether hUC-MSCs-exosomes have a hepatoprotective effect on NAFLD. We constructed NAFLD rat model by high-fat high-fructose feeding. Liver cells (L-O2) were treated with palmitic acid (PA) to mimic NAFLD model. NAFLD rats and PA-treated L-O2 cells were treated with hUC-MSCs-exosomes, and then we determined the influence of exosomes on liver damage and glucose and lipid metabolism in vivo and in vitro. We found that hUC-MSCs-exosomes exhibited an up-regulation of miR-627-5p. Exosomal miR-627-5p promoted cell viability and repressed apoptosis of PA-treated L-O2 cells. Exosomal miR-627-5p also enhanced the expression of G6Pc, PEPCK, FAS and SREBP-1c and suppressed PPARα expression in PA-treated L-O2 cells. Moreover, miR-627-5p interacted with fat mass and obesity-associated gene (FTO) and inhibited FTO expression in L-O2 cells. MiR-627-5p-enriched exosomes improved glucose and lipid metabolism in L-O2 cells by targeting FTO. In vivo, exosomal miR-627-5p ameliorated insulin tolerance, liver damage, glucose and lipid metabolism and reduced lipid deposition in NAFLD rats. Exosomal miR-627-5p also reduced body weight, liver weight, and liver index (body weight/liver weight) in NAFLD rats. In conclusion, these data demonstrate that HUC-MSCs-derived exosomal miR-627-5p improves glucose and lipid metabolism and alleviate liver damage by repressing FTO expression, thereby ameliorating NAFLD progression. Thus, hUC-MSCs-exosomes may be a potential treatment for NAFLD.

Leptin Reduces Plin5 m6A Methylation through FTO to Regulate Lipolysis in Piglets

Perilipin5 (Plin5) is a scaffold protein that plays an important role in lipid droplets (LD) formation, but the regulatory effect of leptin on it is unclear. Our study aimed to explore the underlying mechanisms by which leptin reduces the N⁶-methyladenosine (m⁶A) methylation of Plin5 through fat mass and obesity associated genes (FTO) and regulates the lipolysis. To this end, 24 Landrace male piglets (7.73 ± 0.38 kg) were randomly sorted into two groups, either a control group (Control, n = 12) or a 1 mg/kg leptin recombinant protein treatment group (Leptin, n = 12). After 4 weeks of treatment, the results showed that leptin treatment group had lower body weight, body fat percentage and blood lipid levels, but the levels of Plin5 mRNA and protein increased significantly in adipose tissue (p < 0.05). Leptin promotes the up-regulation of FTO expression level in vitro, which in turn leads to the decrease of Plin5 M⁶A methylation (p < 0.05). In in vitro porcine adipocytes, overexpression of FTO aggravated the decrease of M⁶A methylation and increased the expression of Plin5 protein, while the interference fragment of FTO reversed the decrease of m⁶A methylation (p < 0.05). Finally, the overexpression in vitro of Plin5 significantly reduces the size of LD, promotes the metabolism of triglycerides and the operation of the mitochondrial respiratory chain, and increases thermogenesis. This study clarified that leptin can regulate Plin5 M⁶A methylation by promoting FTO to affect the lipid metabolism and energy consumption, providing a theoretical basis for treating diseases related to obesity.

METTL14 promotes glomerular endothelial cell injury and diabetic nephropathy via m6A modification of α-klotho

Background

N6-Methyladenosine (m6A) modification has been implicated in many bioprocesses. However, its functions in diabetic nephropathy (DN) have not been determined. Here, we investigated the role of METTL14, a key component of the m6A methyltransferase complex, in DN.

Methods

The expression of METTL14 was detected in DN patients and human renal glomerular endothelial cells (HRGECs). In vitro and in vivo experiments were performed to explore the functions of METTL14 on high glocse-induced HRGECs and renal injury of DN mice. We also investigated whether METTL14 works by regulating α-klotho expression through m6A modification.

Results

METTL14 were highly expressed in kidneys of DN patients and high glocse-induced HRGECs both at the mRNA and protein level. Overexpression of METTL14 increased ROS, TNF-α and IL-6 levels and apoptosis in HRGECs. Conversely, METTL14 silence decreased the levels of ROS, TNF-α and IL-6 and cell apoptosis. We confirmed that METTL14 down-regulated α-klotho expression in an m6A-dependent manner. In addition, we also found that METTL14 aggravated renal injury and inflammation of db/db mice, which could partially rescued by α-klotho.

Conclusion

Our data revealed that METTL14 plays a vital role in high glucose-induced glomerular endothelial cells and diabetic nephropathy through m6A modification of α-klotho.

Targeting epigenetics and lncRNAs in liver disease: From mechanisms to therapeutics

Early onset and progression of liver diseases can be driven by aberrant transcriptional regulation. Different transcriptional regulation processes, such as RNA/DNA methylation, histone modification, and ncRNA-mediated targeting, can regulate biological processes in healthy cells, as well also under various pathological conditions, especially liver disease. Numerous studies over the past decades have demonstrated that liver disease has a strong epigenetic component. Therefore, the epigenetic basis of liver disease has challenged our knowledge of epigenetics, and epigenetics field has undergone an important transformation: from a biological phenomenon to an emerging focus of disease research. Furthermore, inhibitors of different epigenetic regulators, such as m⁶A-related factors, are being explored as potential candidates for preventing and treating liver diseases. In the present review, we summarize and discuss the current knowledge of five distinct but interconnected and interdependent epigenetic processes in the context of hepatic diseases: RNA methylation, DNA methylation, histone methylation, miRNAs, and lncRNAs. Finally, we discuss the potential therapeutic implications and future challenges and ongoing research in the field. Our review also provides a perspective for identifying therapeutic targets and new hepatic biomarkers of liver disease, bringing precision research and disease therapy to the modern era of epigenetics.

The association of dietary and plasma fatty acid composition with FTO gene expression in human visceral and subcutaneous adipose tissues

PURPOSE

The human obesity susceptibility gene, FTO, associates with body mass and obesity in humans through regulation of energy expenditure and intake. We aimed to determine how fatty acids in plasma and in diet associate with FTO gene expression in subcutaneous and visceral adipose tissues.

METHODS

In this study, 97 participants aged ≥ 18 years were selected from patients admitted to the hospital for abdominal surgeries. Habitual dietary intake of participants was collected using a valid and reliable food frequency questionnaire (FFQ), from which the intake of fatty acids was quantified. Plasma fatty acids were assessed by gas-liquid chromatography. The mRNA expression of the FTO gene in visceral and subcutaneous adipose tissues obtained by biopsy was measured by Real-Time Quantitative Reverse Transcription PCR. Standardized β-coefficients were calculated by multivariable linear regression.

RESULTS

After adjusting for age, homeostasis model insulin resistance index (HOMA-IR), and body mass index, total fatty acid intake was significantly associated with FTO gene expression in visceral (STZβ = 0.208, P = 0.037) and subcutaneous (STZβ = 0.236, P = 0.020) adipose tissues. Dietary intake of monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA) had positive significant associations with the expression of FTO in visceral (STZβ = 0.227, P = 0.023; STZβ = 0.346, P < 0.001, respectively) and subcutaneous (STZβ = 0.227, P = 0.026; STZβ = 0.274, P = 0.006, respectively) adipose tissues. There were no associations between plasma fatty acids and FTO mRNA expression in either subcutaneous or visceral adipose tissues.

CONCLUSION

The weak association of dietary total fatty acids, MUFA, and PUFA with FTO gene expression in both adipose tissues may highlight the importance of dietary fatty acids composition along with total fat intake in relation to FTO gene expression.

Associations of residing greenness and long-term exposure to air pollution with glucose homeostasis markers

BACKGROUND

Although long-term exposure to higher air pollutants and lower residing greenness related to disorders of glucose homeostasis have been reported, their interaction effects on glucose homeostasis in developing countries remained unclear.

METHODS

A total of 35, 482 participants were obtained from the Henan Rural Cohort (n = 39, 259). Exposure to air pollutants (PM₁, PM_2.5, PM₁₀ and NO₂) were predicted by using a spatiotemporal model-based on satellites data. Residing greenness was reflected by Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) which were derived from satellites data. Independent associations of single or mixture of air pollutant or residing greenness with glucose homeostasis markers were analyzed by quantile regression models and quantile g (qg)-computation method, respectively. Furthermore, interaction effects of residing greenness and air pollution on glucose homeostasis markers were analyzed by generalized additive models.

RESULTS

Positive associations of single or mixture of air pollutants (PM₁, PM_2.5, PM₁₀ or NO₂) with fasting plasma glucose (FPG) were observed, while negative associations of single or mixture of air pollutants with insulin or HOMA-β were observed. Residing greenness was negatively associated with FPG but positively related to insulin or HOMA-β. Quantile regression revealed the heterogeneity were observed in the associations the residing greenness or air pollutants with glucose homeostasis markers (insulin or HOMA-β) across deciles of the glucose homeostasis markers distributions. Furthermore, joint associations of single air pollutant and residing greenness on glucose homeostasis markers were found.

CONCLUSIONS

The results indicated that exposure to air pollution had negative effect on glucose homeostasis markers and these effects may be modified by living in higher green space. These findings suggest that increased residing greenness and air pollution control may have joint effect on decreased the risk of diabetes.

CLINICAL TRIAL REGISTRATION

The Henan Rural Cohort study has been registered at Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699, http://www.chictr.org.cn/showproj.aspx?proj=11375).

Correlations between FTO Gene Polymorphisms and TSH Level in Uyghur Chinese Patients with Type 2 Diabetes

Objective

The aim of this study was to investigate the correlation between polymorphisms in the FTO gene and TSH level in Uyghur patients with type 2 diabetes in the Xinjiang region. Material and Methods. This cohort was made up of 498 Uyghur patients with type 2 diabetes who underwent genotype screening for rs8050136 and rs9939609 using the Sequenom MassARRAY system. The distribution frequencies of the genotypes and alleles at rs8050136 and rs993960 were compared between two patient groups, those with TSH < 2.5 mU/L and those with TSH ≥ 2.5 mU/L group. We further evaluated the relationships between these different genotypes and FT3, FT4, TSH, FPG, and HbA1c expression.

Results

The results suggested the TSH level was 2.281 times higher in rs8050136 CC+CA carriers than in AA genotype (95%CI = 1.024~5.080, P = 0.044) and was 2.417 times higher in rs9939609 TT+TA carriers than in AA genotype (95%CI = 1.257~4.649, P = 0.008) after adjusting for age, sex, and BMI under the recessive model. TSH levels were significantly different between T2DM patients with different FTO genotypes, rs8050136 (P = 0.008) and rs9939609 (P = 0.003), with TSH levels in rs8050136 CC genotype carriers showing a significant increase compared to those in the AA genotype carriers (P = 0.005). Additionally, rs9939609 TT and TA genotype carriers had a significant increase in the TSH level when compared to AA genotype carriers (P = 0.001 and P = 0.031, respectively). The TSH level was also significantly different in these male patients with different genotypes of rs8050136 (P = 0.026) and rs9939609 (P = 0.019). And TSH levels in rs8050136 CC genotype male carriers showing a significant increase compared to those in the AA genotype carriers (P = 0.013) and rs9939609 TT genotype male carriers had a significant increase in TSH level when compared to AA genotype carriers (P = 0.004).

Conclusion

The polymorphisms at rs8050136 and rs9939609 are associated with changes in the TSH level with rs8050136 CC and rs9939609 TT genotypes identified as potential risk factors for increased TSH levels in these male patients.

PI3K/Akt pathway expression in children with different obesity degrees and its relationship with glucolipid metabolism and insulin resistance

OBJECTIVE

This study investigated and analyzed the expression of PI3K/Akt pathway in children with different degree of obesity and its connection with glucolipid metabolism and insulin resistance (IR).

METHODS

157 children with simple obesity, who admitted to our hospital from March 2020 to September 2020, were enrolled as obesity group. These children were divided into mild-group (n=67), moderate-group (n=55) and severe-group (n=35) referring to their body mass index (BMI). Another 60 healthy children admitted to hospitalized were randomly chosen as control group. The expression of PI3K mRNA and Akt mRNA in peripheral blood mononuclear cells (PBMCs) of each group were detected by RT-PCR, and its connection with glucose and lipid metabolism, as well as IR was analyzed.

RESULTS

Each group of children had insignificant difference in FBG (Fasting blood glucose) level (P>0.05). The triglyceride (TG), total cholesterol (TC), Low-density lipoprotein (LDL), Fasting insulin (FINS) and Homeostasis model assessment insulin resistance (HOMA-IR) levels in each obesity group were substantially higher than those in control group (P<0.05), and these levels decreased remarkably with the increase of obesity severity (P<0.05). The high-density lipoprotein (HDL) level of children in each obesity group was notably lower than that of the control group (P<0.05), and the level decreased remarkably with the ascending degree of obesity (P<0.05). The levels of PI3K mRNA and Akt mRNA in PBMCs of children in each obesity group were obviously lower than those in control group (P<0.05), and these index levels decreased much with the increasing worsen of children's obesity degree (P<0.05). The relative expression of PI3K mRNA and Akt mRNA in children with simple obesity was negatively correlated with TG, TC, LDL, FINS and HOMA-IR (P<0.05), positively correlated with HDL (P<0.05), and was not associated with FBG level (P>0.05).

CONCLUSION

The inhibition of PI3K/Akt signaling pathway in children with simple obesity is associated with the abnormal glucolipid metabolism and IR, which affects the occurrence and progression of obesity.

The new coumarin compound Bis 3 ameliorates cognitive disorder and suppresses brain-intestine-liver systematic oxidative stress in high-fat diet mice

High-fat diet (HFD)-induced systemic oxidative damage is critical to the pathological process of obesity and is associated with energy metabolism and cognitive disorders. In our previous research, the coumarin derivative Bis 3 was shown to improve neurological disorders as a potent free radical scavenger. In this study, a 12-week high-fat diet model was established, and mice were randomly divided into 3 groups: standard diet, high-fat diet, and high-fat diet with Bis 3 treatment. Our results demonstrated that Bis 3 attenuated body weight gain and inhibited the development of insulin resistance in high-fat diet-fed mice. Bis 3 protected against high fat-induced intestinal barrier integrity damage and lipid content disorder. HFD-induced hepatocyte lipid metabolism disorder and hepatocyte damage were also alleviated by Bis 3. Moreover, the results of cognitive tests indicated that Bis 3 attenuated high fat-induced cerebral dysfunction, such as cognitive disorders. Importantly, Bis 3 simultaneously ameliorated oxidative stress in the digestive and central nervous systems. These findings suggest that Bis 3 protects against systematic oxidative stress in HFD-induced obese mice, balancing insulin resistance, lipid metabolic disorders, and cognitive disorders through its antioxidative effects, indicating that Bis 3, a novel free radical scavenger, might represent a new therapeutic strategy for high fat-induced chronic systemic redox imbalance.

The value of miRNAs in the prognosis of obese patients receiving bariatric surgery

Bariatric surgery has been the first-line treatment for obesity. Since the 2010s, gradual changes in miRNAs upon surgery have been observed. Substantial research has been undertaken on the role of bariatric surgery in the gastrointestinal tract. However, bariatric surgery research largely ignores the role of miRNAs in organs other than the gastrointestinal tract, while the contribution of miRNAs to this process has received little attention. This review addresses a neglected aspect of miRNAs in obese patients undergoing bariatric surgery, especially the obvious effect on multisystem organs. This finding provides evidence that miRNAs play a complex yet important role in the functional stability of each organ and the weight loss efficacy after bariatric surgery. The results provide a solid evidence base for the mechanism of bariatric surgery. Taking into account incompatible medication adherence associated with adverse outcomes, suggestions were identified for an efficient technical refinement of bariatric surgery with better clinical results.

The fat mass and obesity-associated (FTO) gene allele rs9939609 and glucose tolerance, hepatic and total insulin sensitivity, in adults with obesity

The objective of the study was to assess associations of the rs9939609 FTO allele to glucose tolerance, hepatic and total insulin sensitivity (IS) in individuals with obesity. From a low-dose hyperinsulinemic euglycemic clamp with glucose-tracer, hepatic IS was assessed by rates of basal and suppressed glucose appearance (Ra), a measure of endogenous glucose production (EGP), and the hepatic insulin resistance index (HIR). Total IS was assessed by rates of glucose infusion (GIR), disappearance (Rd), and metabolic clearance (MCR). From a meal test we assessed IS by the Matsuda index and glucose tolerance by glucose and insulin measurements in the fasted state and postprandially for 2.5 h. The meal test was performed in 97 healthy individuals with BMI ≥35 in similar-sized risk-allele groups (n = 32 T/T, 31 A/T, and 34 A/A), and 79 of them performed the clamp. We analyzed outcomes separately for males and females, and adjusted glucose Ra, Rd, MCR, GIR, and HIR for fat mass. We did not find genotype effects on EGP. Among males, genotype A/A was associated with a significantly lower glucose Rd, MCR, and Matsuda index score relative to genotype T/T. Glucose tolerance was significantly lower in males with genotype A/T vs. T/T and A/A. For females, there were no genotype effects on hepatic or total IS, or on glucose tolerance. Independently of genotypes, females displayed a significantly better hepatic and total IS, and better glucose tolerance than males. We conclude that in subjects with similar obesity we did not register any FTO risk-allele effect on hepatic IS. A FTO risk-allele effect on total IS was registered in males only, findings which need to be reproduced in further studies. Results confirm marked differences in IS between the biological sexes and extend present knowledge by demonstrating a lower endogenous glucose production in females vs. males in uniformly obese individuals.