FNDC5 (irisin) gene and exceptional longevity: a functional replication study with rs16835198 and rs726344 SNPs

Risk Polymorphisms of FNDC5, BDNF, and NTRK2 and Poor Education Interact and Aggravate Age-Related Cognitive Decline

Cognitive abilities tend to decline with aging, with variation between individuals, and many studies seek to identify genetic biomarkers that more accurately anticipate risks related to pathological aging. We investigated the influence of BDNF, NTRK2, and FNDC5 single nucleotide polymorphisms (SNPs) on the cognitive performance of young and older adults with contrasting educational backgrounds. We addressed three questions: (1) Is education associated with reduced age-related cognitive decline? (2) Does the presence of SNPs explain the variation in cognitive performance observed late in life? (3) Is education differentially associated with cognition based on the presence of BDNF, NTRK2, or FNDC5 polymorphisms? We measured the cognitive functions of young and older participants, with lower and higher education, using specific and sensitive tests of the Cambridge Automated Neuropsychological Test Assessment Battery. A three-way ANOVA revealed that SNPs were associated with differential performances in executive functions, episodic memory, sustained attention, mental and motor response speed, and visual recognition memory and that higher educational levels improved the affected cognitive functions. The results revealed that distinct SNPs affect cognition late in life differentially, suggesting their utility as potential biomarkers and emphasizing the importance of cognitive stimulation that advanced education early in life provides.

RS3480 Polymorphism of FNDC5/Irisin Is Associated with Type 2 Diabetes Mellitus in Maya-Mestizo Women

Objective: To investigate the possible association between rs3480 and rs16835198 of the fibronectin type III domain containing 5 (FNDC5)/Irisin and their haplotypes with the presence of type 2 diabetes mellitus (T2DM) in Maya-Mestizo women. Methods: We studied 547 postmenopausal women of Maya-Mestizo origin. The diagnosis of T2DM was based on the criteria of the American Diabetes Association. DNA was obtained from blood leukocytes. rs3480 and rs16835198 of FNDC5/Irisin were studied using real-time polymerase chain reaction allelic discrimination. Deviations from Hardy-Weinberg equilibrium and alleles differences, as well as genotype frequencies between groups, were assessed by χ2 tests. Using logistic regression analysis, the odds ratio and 95% confidence intervals were calculated to estimate the association between both polymorphisms of FNDC5/Irisin and the presence of T2DM. Pairwise linkage disequilibrium between polymorphisms was calculated by direct correlation r2, and haplotype analysis was conducted. Results: We found that the G-allele of rs3480, as well as under a dominant model, this polymorphism was significantly associated with T2DM (P = 0.028 and P = 0.003, respectively). Besides, one haplotype was associated with T2DM (P = 0.035). Conclusions: Our results suggest that the FNDC5/Irisin rs3480, and one haplotype formed by rs3480 and rs16835198 were associated with the risk of presenting T2DM in Maya-Mestizo women.

Irisin enhances longevity by boosting SIRT1, AMPK, autophagy and telomerase

Ageing is characterised by the accumulation of molecular and cellular damage through time, leading to a decline in physical and mental abilities. Currently, society has experienced a rapid increase in life expectancy, which has led to an increase in age-associated diseases. Therefore, it is crucial to study the process of ageing to guarantee the best conditions in the final stages of life. In recent years, interest has increased in a myokine known as irisin, which is secreted during physical exercise. This polypeptide hormone is produced by various organs, mainly muscle, and once it is released into the blood, it performs a wide variety of functions that are involved in metabolic control and may be relevant during some of the diseases associated with ageing. The aim of this review is to highlight the recent studies of irisin, such as its mechanism of expression, blood release, distribution, tissue target and participation in various cellular metabolic reactions and the relationship with key anti-ageing pathways such as adenosine monophosphate-activated protein kinase, silent information regulator T 1, autophagy and telomerase. In conclusion, irisin is a key player during the ageing process and it could be a novel target molecule for the therapeutic approach to boost longevity pathways. However, more research will be necessary to use this promising hormone for this gain.

LPL, FNDC5 and PPARγ gene polymorphisms related to body composition parameters and lipid metabolic profile in adolescents from Southern Italy

Background

Plasma lipid profile and anthropometric variables are known to be under strong genetic control and the identification of genetic variants associated with bioclinical parameters is of considerable public health importance. In this study, a young cohort of healthy individuals was genotyped for genes related to health and pathological conditions, to analyze the association of single nucleotide polymorphisms (SNPs) with different bioclinical parameters, adherence to the Mediterranean Diet (MD) and physical activity, studying the role of lifestyle and body composition parameters on biochemical metabolic profile.

Methods

Association analysis of single variants in the genes of lipoprotein lipase (LPL), fibronectin type III domain containing protein 5 (FNDC5), and peroxisome proliferator-activated receptor-gamma (PPARγ) and haplotype analyses were performed.

Results

Multiple (n = 14) common variants in the three genes demonstrated a significant effect on plasma lipoprotein-lipid levels and/or on biochemical parameters in our sample. Specifically, SNPs were related to lipid metabolism (rs3866471, rs4922115, rs11570892, rs248, rs316, rs1059507, rs1801282) or glycemic profile (rs3208305) or anthropometric parameters (rs3480, rs726344, rs1570569) for a total of 26 significant associations (P < 0.01 and/or P < 0.05) and two haplotypes, for the first time, were strongly associated with lipid and body composition parameters. Interestingly, we identified twenty-four new variants not previously described in the literature and a novel significant association between rs80143795 and body composition.

Conclusions

In this study we confirm the association between these SNPs on lipid metabolism and body parameters also in a young cohort, indicating the important role of these genetic factors as determinants of health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03314-w.

Associations between rs3480 and rs16835198 gene polymorphisms of FNDC5 with type 2 diabetes mellitus susceptibility: a meta-analysis

BACKGROUND

FNDC5 is a novel and important player in energy regulation related to glucose metabolism and insulin levels. Thus, it may affect the incidence of type 2 diabetes mellitus (T2DM). Nevertheless, the association between FNDC5 single nucleotide polymorphisms (SNPs) and susceptibility to T2DM remains unclear. The aim of this meta-analysis was to explore whether the SNPs, rs3480 and rs16835198, are associated with the risk of T2DM.

METHODS

Studies published before February 1^st, 2022 were screened to identify the included studies. R software was also applied for calculation of odds ratio (OR), 95% confidence interval (95% CI), heterogeneity, and sensitivity analysis.

RESULTS

Seven studies for rs3480 (involving 5475 patients with T2DM and 4855 healthy controls) and five studies for rs16835198 (involving 4217 patients with T2DM and 4019 healthy controls) were included in this meta-analysis. The results revealed a statistically significant association of rs3480 with T2DM under homozygote (GG vs AA: OR = 1.76, 95% CI = 1.31-2.37, P = 0.0002, I² = 59%) genetic model. However, there was no statistically significant correlation between rs16835198 and susceptibility to T2DM under allelic (G vs T: OR = 1.33, 95% CI = 0.94-1.89, P = 0.11, I² = 84%), heterozygote (GT vs TT: OR = 1.17, 95% CI = 0.80-1.69, P = 0.42, I² = 71%), homozygote (GG vs TT: OR = 1.35, 95% CI = 0.95-1.94, P = 0.10, I² = 62%), recessive (GG+GT vs TT: OR = 1.25, 95% CI = 0.88-1.79, P = 0.22, I² = 72%), and dominant (GG vs GT+GG: OR = 1.20, 95% CI = 0.96-1.50, P = 0.11, I² = 46%) genetic models.

CONCLUSIONS

The present meta-analysis revealed that rs3480 in FNDC5 is significantly associated with susceptibility to T2DM, while rs16835198 does not show such an association.

Common single nucleotide polymorphisms in the FNDC5 gene and serum irisin levels in acute myocardial infarction

OBJECTIVE

Acute myocardial infarction (AMI) is the most common type of coronary artery disease. The irisin hormone encoded by the fibronectin type III domain-containing protein-5 (FNDC5) gene is synthesized in muscle, heart, and fat tissues. The present study aims to investigate serum irisin concentrations and FNDC5 genetic variants in patients with AMI through comparison with controls.

METHODS

This study included 225 patients with AMI and 225 healthy subjects. Blood samples were obtained from patients during the first 1-24 hours after AMI. Serum irisin concentration was measured with enzyme-linked immunosorbent assay (ELISA). The variants of rs16835198, rs3480, and rs726344 in the FNDC5 gene were genotyped with real time polymerase chain reaction (RT-PCR).

RESULTS

Compared with control serum irisin concentrations were significantly lower in patients with AMI. Serum irisin concentrations of patients with AMI showed a significant and gradual decrease from 6 hours up to 24 hours (p<0.05). There were no significant differences between the patient and control groups based on genotype and allele frequencies of rs16835198, rs3480, and rs726344 in the FNDC5 gene (p>0.05). However, the frequency of the TT genotype in male patients with AMI (6.4%) was significantly lower compared with control male subjects (16.2%). In addition, the GGT haplotype was identified as the protective haplotype against the risk of AMI (p<0.001; odds ratio=0.107).

CONCLUSIONS

The findings of the study suggest that serum irisin concentration could serve as a novel biological marker for the early diagnosis of AMI.

A pilot study on the relation between irisin single-nucleotide polymorphism and risk of myocardial infarction

BACKGROUND

Myocardial infarction (MI) is the major cause of death and disability worldwide. Many recent studies revealed the relationship between circulating irisin levels, endothelial dysfunctions and subclinical atherosclerosis in adult patients.

OBJECTIVES

The aim of this study was to investigate the distribution of Irisin gene single nucleotide polymorphism in patients with MI and its association with other clinical and laboratory variables in these patients.

PATIENTS AND METHODS

This study was carried out in 100 patients with MI, and 100 healthy subjects served as controls. All studied subjects underwent laboratory investigations, including measurement of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c) high-density lipoprotein cholesterol (HDL-c), creatinine kinase-MB (CK-MB), troponin I (TnI) and genotyping of rs 3480 and rs726344 of Irisin genes using the TaqMan Allelic Discrimination assay technique.

RESULTS

There was a significant difference of Irisin genotypes in patients when compared to controls. By estimating odd ratio (OR) an association was found between G allele of rs 3480 and A allele of rs726344with increase the risk of developing myocardial infarction by 4.03 and 3.47 fold respectively. GG of rs 3480 carriers had significantly increased Troponin I and triglyceride levels, while GA carriers of rs726344 had significantly increased CKMB, Total cholesterol, LDLc, HDLc, troponin I and triglyceride levels compared with other genotypes.

CONCLUSION

G allele of rs 3480 and A allele of rs726344can considered as genetic risk factors for MI; these findings could have an impact on preventive strategy for myocardial infarction.

Epistasis, physical capacity-related genes and exceptional longevity: FNDC5 gene interactions with candidate genes FOXOA3 and APOE

BACKGROUND

Forkhead box O3A (FOXOA3) and apolipoprotein E (APOE) are arguably the strongest gene candidates to influence human exceptional longevity (EL, i.e., being a centenarian), but inconsistency exists among cohorts. Epistasis, defined as the effect of one locus being dependent on the presence of 'modifier genes', may contribute to explain the missing heritability of complex phenotypes such as EL. We assessed the potential association of epistasis among candidate polymorphisms related to physical capacity, as well as antioxidant defense and cardiometabolic traits, and EL in the Japanese population. A total of 1565 individuals were studied, subdivided into 822 middle-aged controls and 743 centenarians.

RESULTS

We found a FOXOA3 rs2802292 T-allele-dependent association of fibronectin type III domain-containing 5 (FDNC5) rs16835198 with EL: the frequency of carriers of the FOXOA3 rs2802292 T-allele among individuals with the rs16835198 GG genotype was significantly higher in cases than in controls (P < 0.05). On the other hand, among non-carriers of the APOE 'risk' ε4-allele, the frequency of the FDNC5 rs16835198 G-allele was higher in cases than in controls (48.4% vs. 43.6%, P < 0.05). Among carriers of the 'non-risk' APOE ε2-allele, the frequency of the rs16835198 G-allele was higher in cases than in controls (49% vs. 37.3%, P < 0.05).

CONCLUSIONS

The association of FDNC5 rs16835198 with EL seems to depend on the presence of the FOXOA3 rs2802292 T-allele and we report a novel association between FNDC5 rs16835198 stratified by the presence of the APOE ε2/ε4-allele and EL. More research on 'gene*gene' and 'gene*environment' effects is needed in the field of EL.

Is irisin the new player in exercise-induced adaptations or not? A 2017 update

Irisin is produced by a proteolytic cleavage of fibronectin type III domain-containing protein 5 (FNDC5) and has emerged as a potential mediator of exercise-induced energy metabolism. The purpose of this study was to review the results of studies that investigated irisin responses to acute and chronic exercise and provide an update. A comprehensive search in the databases of MEDLINE was performed (74 exercise studies). The focus of the analysis was on data concerning FNDC5 mRNA expression in skeletal muscle and circulating irisin concentration relatively to exercise mode, intensity, frequency and duration and the characteristics of the sample used. Circulating irisin levels may either not relate to FNDC5 transcription or expression of the later precedes irisin rise in the blood. Acute speed/strength and endurance exercise protocols represent potent stimuli for irisin release if they are characterized by adequate intensity and/or duration. There are no reports regarding irisin responses to field sport activities. Although animal studies suggest that irisin may also respond to systematic exercise training, the majority of human studies has produced contradictory results. Certain methodological issues need to be considered here such as the analytical assays used to measure irisin concentration in the circulation. Results may also be affected by subjects’ age, conditioning status and exercise intensity. The role of irisin as a moderator of energy metabolism during exercise remains to be seen.

SNPs in FNDC5 (irisin) are associated with obesity and modulation of glucose and lipid metabolism in Saudi subjects

BACKGROUND

Irisin is a recently identified myokine that plays an important role in preventing obesity and insulin resistance. We investigated whether the common FNDC5 (irisin precursor) gene variants influence susceptibility to obesity and type 2 diabetes (T2D) and verified the impact of FNDC5 gene variants on serum irisin levels, glucose and lipid metabolism in a Saudi population.

METHODS

Genomic DNA from 814 (394 T2DM and 414 controls) subjects were genotyped for the five common SNPs (rs3480A/G, rs1746661G/T, rs1298190A/G, rs726344A/G and rs1570569G/T) of the FNDC5 gene using the TaqMan genotyping assay. Biochemical parameters and hematic concentrations of irisin and insulin as well as anthropometric indices were collected.

RESULTS

Serum irisin levels were higher in T2DM patients compared to controls (p < 0.0001). Analyses of FNDC5 SNPs showed that: 1) The rs3480 GG associates with decreased risk of obesity (p = 0.005; odds ratio: 0.48) and lower body mass index (BMI) values (p = 0.03). In addition, GGAAG was identified as the protective haplotype against risk of obesity (p = 0.001; odds ratio: 0.23). 2) The rs1746661 G allele associates with higher triglyceride (TG) levels (p = 0.019). 3) The rs157069 TT genotype associates with higher fasting insulin (p = 0.029) and HOMA-IR (p = 0.002) as well as with lower circulating irisin levels (p = 0.016).

CONCLUSIONS

SNPs in FNDC5 gene correlates with obesity and glucose-lipid metabolism possibly because they modulate the serum levels of irisin.