The Pro12Ala polymorphism of the PPAR-gamma2 gene affects associations of fish intake and marine n-3 fatty acids with glucose metabolism

CRISPR/Cas9-Mediated Knockout of miR-130b Affects Mono- and Polyunsaturated Fatty Acid Content via PPARG-PGC1α Axis in Goat Mammary Epithelial Cells

MicroRNA (miRNA)-130b, as a regulator of lipid metabolism in adipose and mammary gland tissues, is actively involved in lipogenesis, but its endogenous role in fatty acid synthesis remains unclear. Here, we aimed to explore the function and underlying mechanism of miR-130b in fatty acid synthesis using the CRISPR/Cas9 system in primary goat mammary epithelial cells (GMEC). A single clone with deletion of 43 nucleotides showed a significant decrease in miR-130b-5p and miR-130b-3p abundances and an increase of target genes PGC1α and PPARG. In addition, knockout of miR-130b promoted triacylglycerol (TAG) and cholesterol accumulation, and decreased the proportion of monounsaturated fatty acids (MUFA) C16:1, C18:1 and polyunsaturated fatty acids (PUFA) C18:2, C20:3, C20:4, C20:5, C22:6. Similarly, the abundance of fatty acid synthesis genes ACACA and FASN and transcription regulators SREBP1c and SREBP2 was elevated. Subsequently, interference with PPARG instead of PGC1α in knockout cells restored the effect of miR-130b knockout, suggesting that PPARG is responsible for miR-130b regulating fatty acid synthesis. Moreover, disrupting PPARG inhibits PGC1α transcription and translation. These results reveal that miR-130b directly targets the PPARG-PGC1α axis, to inhibit fatty acid synthesis in GMEC. In conclusion, miR-130b could be a potential molecular regulator for improving the beneficial fatty acids content in goat milk.

Does polymorphisms in PPAR and APOE genes modify associations between fatty acid desaturase (FADS), n-3 long-chain PUFA and cardiometabolic markers in 8-11-year-old Danish children?

n-3 Long-chain PUFA (LCPUFA) can improve cardiometabolic blood markers, but studies in children are limited. SNP in the FADS genes, which encode fatty acid desaturases, influence endogenous LCPUFA production. Moreover, SNP in genes that encode PPAR and apoE may modulate the effects of n-3 LCPUFA. We explored whether FADS polymorphisms were associated with blood cholesterol and TAG, insulin and glucose and whether polymorphisms in PPAR and APOE modified associations between FADS or n-3 LCPUFA status and the cardiometabolic blood markers. We measured fasting cholesterol and TAG, insulin, glucose and n-3 LCPUFA in 757 Danish 8-11-year-old children and genotyped SNP in FADS (rs1535 and rs174448), PPARG2 (rs1801282), PPARA (rs1800206) and APOE (rs7412+rs429358). Carriage of two FADS rs174448 major alleles was associated with lower TAG (P = 0·027) and higher HDL-cholesterol (P = 0·047). Blood n-3 LCPUFA was inversely associated with TAG and insulin in PPARG2 minor allele carriers and positively with LDL-cholesterol in major allele homozygotes (Pn-3 LCPUFA × rs180182 < 0·01). Associations between n-3 LCPUFA and cardiometabolic markers were not modified by APOE genotype (Pn-3 LCPUFA × APOE > 0·11), but interaction between FADS rs1535 and APOE showed that rs1535 major allele homozygotes who also carried APOE2 had higher HDL-cholesterol than all other genotype combinations (Prs1535 × APOE = 0·019, pairwise-P < 0·05). This indicates that FADS genotypes, which increase endogenous LCPUFA production, may beneficially affect children's cardiometabolic profile in a partly APOE-dependent manner. Also, the degree to which children benefit from higher n-3 LCPUFA intake may depend on their PPARG2 genotype.

Diversifying Food Systems in the Pursuit of Sustainable Food Production and Healthy Diets

Increasing demand for nutritious, safe, and healthy food because of a growing population, and the pledge to maintain biodiversity and other resources, pose a major challenge to agriculture that is already threatened by a changing climate. Diverse and healthy diets, largely based on plant-derived food, may reduce diet-related illnesses. Investments in plant sciences will be necessary to design diverse cropping systems balancing productivity, sustainability, and nutritional quality. Cultivar diversity and nutritional quality are crucial. We call for better cooperation between food and medical scientists, food sector industries, breeders, and farmers to develop diversified and nutritious cultivars that reduce soil degradation and dependence on external inputs, such as fertilizers and pesticides, and to increase adaptation to climate change and resistance to emerging pests.

Association between PPAR-γ2 Pro12Ala genotype and insulin resistance is modified by circulating lipids in Mexican children

The Pro12Ala (rs1801282) polymorphism in peroxisome proliferator-activated receptor-γ2 (PPAR-γ2) has been convincingly associated with insulin resistance (IR) and type 2 diabetes (T2D) among Europeans, in interaction with a high-fat diet. Mexico is disproportionally affected by obesity and T2D however, whether the Pro12Ala polymorphism is associated with early metabolic complications in this population is unknown. We assessed the association of PPAR-γ2 Pro12Ala with metabolic traits in 1457 Mexican children using linear regression models. Interactions between PPAR-γ2 Pro12Ala and circulating lipids on metabolic traits were determined by adding an interaction term to regression models. We observed a high prevalence of overweight/obesity (49.2%), dyslipidemia (34.9%) and IR (11.1%). We detected nominally significant/significant interactions between lipids (total cholesterol, HDL-cholesterol, LDL-cholesterol), the PPAR-γ2 Pro12Ala genotype and waist-to-hip ratio, fasting insulin, HOMA-IR and IR (9.30 × 10⁻⁴  ≤ P_interaction ≤ 0.04). Post-hoc subgroup analyses evidenced that the association between the PPAR-γ2 Pro12Ala genotype and fasting insulin, HOMA-IR and IR was restricted to children with total cholesterol or LDL-cholesterol values higher than the median (0.02 ≤ P ≤ 0.03). Our data support an association of the Pro12Ala polymorphism with IR in Mexican children and suggest that this relationship is modified by dyslipidemia.

Effects on metabolic markers are modified by PPARG2 and COX2 polymorphisms in infants randomized to fish oil

Long-chain n-3 fatty acids (n-3 LCPUFA) improve blood pressure (BP) and lipid profile in adults and improve insulin sensitivity in rodents. We have previously shown that n-3 LCPUFA reduces BP and plasma triacylglycerol (TAG) in infants. Few studies have found effects on glucose homeostasis in humans. We explored possible effect modification by FADS, PPARG2, and COX2 genotypes to support potential effects of n-3 LCPUFA on metabolic markers in infants. Danish infants (133) were randomly allocated to daily supplementation with a teaspoon (~5 mL/day) of fish oil (FO) or sunflower oil (SO) from 9 to 18 months of age. Before and after the intervention, we assessed BP, erythrocyte n-3 LCPUFA, plasma lipid profile, insulin, and glucose in addition to functional single nucleotide polymorphisms in FADS, PPARG2, and COX2. At 18 months, plasma TAG was lower in the FO compared with SO group (p = 0.014). This effect was modified by PPARG2-Pro12Ala, as TAG only decreased among heterozygotes. FO supplemented PPARG2 Pro12Ala heterozygotes also had decreased plasma glucose compared with the SO group (p = 0.043). The effect of FO on mean arterial BP at 18 months was gender dependent (p = 0.020) and reduced in boys only (p = 0.028). Diastolic BP was, however, lower among all FO supplemented homozygous COX2-T8473C variant allele carriers compared with the SO group (p = 0.001). In conclusion, our results confirm that FO supplementation in late infancy reduces TAG and BP and indicates that the effects are mediated via peroxisome proliferator-activated receptor-γ and cyclooxygenase-2. Furthermore, FO reduced plasma glucose only in PPARG2 heterozygotes.

Gender, body mass index, and PPARγ polymorphism are good indicators in hyperuricemia prediction for Han Chinese

Hyperuricemia is closely associated with obesity and metabolic abnormalities, which is also an independent risk factor for cardiovascular diseases. The PPARγ gene, which is linked to obesity and metabolic abnormalities in Han Chinese, might be considered a top candidate gene that is involved in hyperuricemia. This study recruited 457 participants, aged 20-40 years old, to investigate the associations of the PPARγ gene and metabolic parameters with hyperuricemia. Three tag-single nucleotide polymorphisms, rs2292101, rs4684846, and rs1822825, of the PPARγ gene were selected to explore their association with hyperuricemia. Risk genotypes on rs1822825 of the PPARγ gene exhibited statistical significance with hyperuricemia (odds ratio: 1.9; 95% confidence interval: 1.05-3.57). Although gender, body mass index (BMI), serum total cholesterol concentration, or protein intake per day were statistically associated with hyperuricemia, the combination of BMI, gender, and rs1822825, rather than that of age, serum lipid profile, blood pressure, and protein intake per day, satisfied the predictability for hyperuricemia (sensitivity: 69.3%; specificity: 83.7%) in Taiwan-born obese Han Chinese. BMI, gender, and the rs1822825 polymorphism in the PPARγ gene appeared good biomarkers in hyperuricemia; therefore, these powerful indicators may be included in the prediction of hyperuricemia to increase the accuracy of the analysis.

PPARG2 Pro12Ala and ADAMTS9 rs4607103 as "insulin resistance loci" and "insulin secretion loci" in Italian individuals. The GENFIEV study and the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS) 4

We investigated cross-sectionally whether the type 2 diabetes (T2DM) risk alleles of rs1801282 (PPARG2) and rs4607103 (ADAMTS9) were associated with T2DM and/or insulin sensitivity (IS) and beta cell function (βF) in Italians without and with newly diagnosed T2DM. In 676 nondiabetic subjects (336 NGR and 340 IGR) from the GENFIEV study and in 597 patients from the Verona Newly Diagnosed Type 2 Diabetes Study (VNDS), we (1) genotyped rs1801282 and rs4607103, (2) assessed βF by C-peptide/glucose modeling after OGTT, and (3) assessed IS by HOMA-IR in both studies and by euglycemic insulin clamp in VNDS only. Logistic, linear, and two-stage least squares regression analyses were used to test (a) genetic associations with T2DM and with pathophysiological phenotypes, (b) causal relationships of the latter ones with T2DM by a Mendelian randomization design. Both SNPs were associated with T2DM. The rs4607103 risk allele was associated to impaired βF (p < 0.01) in the GENFIEV study and in both cohorts combined. The rs1801282 genotype was associated with IS both in the GENFIEV study (p < 0.03) and in the VNDS (p < 0.03), whereas rs4607103 did so in the VNDS only (p = 0.01). In a Mendelian randomization design, both HOMA-IR (instrumental variables: rs1801282, rs4607103) and βF (instrumental variable: rs4607103) were related to T2DM (p < 0.03-0.01 and p < 0.03, respectively). PPARG2 and ADAMTS9 variants are both associated with T2DM and with insulin resistance, whereas only ADAMTS9 may be related to βF. Thus, at least in Italians, they may be considered bona fide "insulin resistance genes".

N-3 polyunsaturated fatty acids: relationship to inflammation in healthy adults and adults exhibiting features of metabolic syndrome

Individuals with metabolic syndrome (MetS) have a higher risk of type 2 diabetes and cardiovascular disease, therefore, research has been directed at reducing various components that contribute to MetS and associated metabolic impairments, including chronic low-grade inflammation. Epidemiological, human, animal and cell culture studies provide evidence that dietary n-3 polyunsaturated fatty acids (n-3 PUFA), including alpha-linolenic acid (18:3n-3, ALA), eicosapentaenoic acid (20:5n-3, EPA) and/or docosahexaenoic acid (22:6n-3, DHA) may improve some of the components associated with MetS. The current review will discuss recent evidence from human observational and intervention studies that focused on the effects of ALA, EPA or DHA on inflammatory markers in healthy adults and those with one or more features of MetS. Observational studies in healthy adults support the recommendation that a diet rich in n-3 fatty acids may play a role in preventing and reducing inflammation, whereas intervention studies in healthy adults have yielded inconsistent results. The majority of intervention studies in adults with features of MetS have reported a benefit for some inflammatory measures; however, other studies using high n-3 fatty acid doses and long supplementation periods have reported no effect. Overall, the data reviewed herein support recommendations for regular fatty fish consumption and point toward health benefits in terms of lowering inflammation in adults with one or more features of MetS.

Interactions between dietary n-3 fatty acids and genetic variants and risk of disease

Nutritional genomics has undergone rapid development and the concept is now very popular with the general public. Therefore, there is increasing demand for knowledge on adapting dietary composition to the genome. Our aim has been to undertake a systematic review so as to find out the level of evidence existing on whether the effects of n-3 fatty acids on health can be modulated by genetic variation. A systematic literature search was conducted on studies that jointly analyse the effect of one or more genetic variants in candidate genes and n-3 fatty acids. Both observational and experimental studies were included. Results are classified in accordance with whether the study was undertaken on intermediate phenotypes (plasma lipid concentrations, glucose, inflammation markers, anthropometric measurements) or disease phenotypes (cancer, cardiovascular diseases, metabolic syndrome, etc) and whether it was experimental or observational. A wide diversity of genetic variants and little consistency in the publication of replication studies was found. Greater consistency was observed in studies that involved the FADS1 and FADS2 locus in the determination of n-3 fatty acid concentrations in biological samples. Most of the studies were designed to measure gene-diet interactions and not diet-gene interactions. Despite the fact that multiple studies have shown statistically significant interactions between n-3 fatty acids and certain genetic variants on intermediate and disease phenotypes, the individual level of evidence is very low and recommendations cannot be made on increasing or reducing the intake of n-3 fatty acids based on each individual's genotype.

Gene-environment interactions in the development of type 2 diabetes: recent progress and continuing challenges

Type 2 diabetes (T2D) is thought to arise from the complex interplay of both genetic and environmental factors. Since the advent of genome-wide association studies (GWAS), we have seen considerable progress in our understanding of the role that genetics and gene-environment interactions play in the development of T2D. Recent work suggests that the adverse effect of several T2D loci may be abolished or at least attenuated by higher physical activity levels or healthy lifestyle, whereas low physical activity and dietary factors characterizing a Western dietary pattern may augment it. However, there still remain inconsistencies warranting further investigation. Lack of statistical power and measurement errors for the environmental factors continue to challenge our efforts for characterizing interactions. Although our recent focus on established T2D loci is reasonable, we may be overlooking many other potential loci not captured by recent T2D GWAS. Agnostic approaches to the discovery of gene and environment interactions may address this possibility, but their application to the field is currently limited and still faces conceptual challenges. Nonetheless, continued investment in gene-environment interaction studies through large collaborative efforts holds promise in furthering our understanding of the interplay between genetic and environmental factors.

An age-dependent diet-modified effect of the PPARγ Pro12Ala polymorphism in children

Variation in the peroxisome proliferator-activated receptor γ gene alters the risk for adiposity in adults, with evidence of interaction with diet. We investigated the age-related association between the Pro12Ala variant (rs1801282) and diet in obesity-related traits in children. The Pro12Ala variant was assayed in 2102 young children aged 1 to 6 years and in 794 periadolescent children aged 10 to 12 years of Greek origin. In both cohorts, no differences were found in obesity traits between the Ala allele carriers and Pro/Pro homozygotes. Sex-stratified analysis showed that, in periadolescent boys, Ala carriers exhibited lower measures of skinfolds (triceps: 16.9 ± 6.9 vs 19.4 ± 7.9 mm, P = .01; subscapular: 9.6 ± 4.5 vs 11.2 ± 5.4 mm, P = .02). On the other hand, young girls who were Ala carriers presented higher measures of triceps skinfold thickness (10.5 ± 3.0 vs 9.9 ± 2.8 mm, P = .04). Nominal gene-diet interactions were revealed in periadolescents for saturated fatty acid (SFA) intake and skinfolds (P for interaction = .05). In Pro/Pro homozygous young girls, SFA and total fat (TF) intake was positively associated with higher body mass index (BMI) (P = .01), waist circumference (P = .02), and skinfold thickness (triceps-SFA: P = 10⁻⁵, triceps-TF: P = 10⁻⁹, subscapular-SFA: P = 10⁻⁶, subscapular-TF: P = 10⁻⁴). For Pro/Pro homozygotes, unsaturated fat intake was inversely associated with BMI (P = .04) in young girls, and with BMI (P = .03), waist circumference (P = .03), and triceps (P = .02) in periadolescent boys. Our results suggest that adiposity in children is influenced by the Pro12Ala polymorphism in a sex-specific and age-dependent manner. We also demonstrate evidence of an age-dependent gene-diet (SFA, TF) interaction, suggesting that the type of fat intake modifies the effect of the Pro12 allele on obesity-related measures.

Erythrocyte membrane phospholipid polyunsaturated fatty acids are related to plasma C-reactive protein and adiponectin in middle-aged German women and men

PURPOSE

Modulation of circulating inflammatory markers and adiponectin may link PUFA to risk of diabetes and cardiovascular diseases. We investigated erythrocyte n-6 and n-3 PUFA in relation to plasma C-reactive protein (CRP) and adiponectin, and whether the Pro12Ala polymorphism in the PPARγ2 gene (PPARG2) modified these associations.

METHODS

We conducted a cross-sectional analysis among 1,222 women and 758 men participating in the EPIC-Potsdam study.

RESULTS

Most notably, in both sexes, higher linoleic acid (LA) was related to lower CRP (geometric mean outcome [mg/L], quintile 1, quintile 5, p for trend ≤ 0.01 unless otherwise stated: 0.95, 0.61 [women], 0.67, 0.51 [men]) and higher adiponectin (7.9, 9.1 [women], 5.3, 6.1 [men]), whereas higher γ-linolenic acid (GLA) and dihomo-γ-linolenic acid (DGLA) were related to higher CRP (GLA: 0.63, 0.92 [women], 0.55, 0.70, p = 0.08 [men], DGLA: 0.55, 1.07 [women], 0.52, 0.76 [men]) and lower adiponectin (GLA: 8.6, 8.0 [women], 5.8, 5.4, p = 0.08 [men], DGLA: 9.2, 7.9 [women], 5.9, 5.4, p = 0.08 [men]) adjusting for age and lifestyle. The associations mostly did neither strongly nor significantly vary by PPARG2 genotype. In women, Pro12Ala appeared to interact with arachidonic acid on CRP (p = 0.04), as well as with docosatetraenoic acid on CRP (p = 0.08) and adiponectin (p = 0.02).

CONCLUSIONS

Our findings suggest that erythrocyte PUFA, particularly LA and n-6 higher unsaturated fatty acids, are related to circulating CRP and adiponectin. They do not indicate that PUFA strongly interact with the PPARG2 Pro12Ala variant on these risk markers.

Fatty acid interactions with genetic polymorphisms for cardiovascular disease

PURPOSE OF REVIEW

The number of studies investigating interactions between genes and nutrients for cardiovascular disease continues to grow, and holds tremendous potential for reducing disease risk at the level of the individual genotype. However, understanding the limitations and challenges of interaction studies, whether of observational or interventional design, is essential for critical evaluation of these studies.

RECENT FINDINGS

Nutrient-gene interactions for cardiovascular disease both parallel and extend nutrition studies, encompassing both traditional and novel cardiovascular risk factors. Fatty acid quality, lipid metabolism, inflammation, postprandial metabolism, fatty liver and macronutrient-gene interactions for obesity and metabolic syndrome represent a subset of the major areas of recent focus. With few exceptions, however, studies of gene-nutrient interactions are limited to a single population.

SUMMARY

Gene-nutrient research will continue to expand as genome-wide association studies uncover new sources of genetic variability associated with cardiovascular risk. However, in addition to investigation of newly discovered variants, continuing efforts must focus on the confirmation of previously reported genetic associations and interactions in additional populations.

Isomer-specific effects of CLA on gene expression in human adipose tissue depending on PPARgamma2 P12A polymorphism: a double blind, randomized, controlled cross-over study

BACKGROUND

Peroxisome proliferator-activated receptor (PPAR)gamma is a key regulator in adipose tissue. The rare variant Pro12Ala of PPARgamma2 is associated with a decreased risk of insulin resistance. Being dietary PPARgamma ligands, conjugated linoleic acids (CLAs) received considerable attention because of their effects on body composition, cancer, atherosclerosis, diabetes, obesity and inflammation, although some effects were only demonstrated in animal trials and the results in human studies were not always consistent. In the present study effects of CLA supplementation on genome wide gene expression in adipose tissue biopsies from 11 Ala12Ala and 23 Pro12Pro men were investigated. Subjects underwent four intervention periods (4 wk) in a randomized double blind cross-over design receiving 4.25 g/d of either cis-9, trans-11 CLA, trans-10,cis-12 CLA, 1:1 mixture of both isomers or a reference linoleic acid oil preparation. After each intervention biopsies were taken, whole genome expression microarrays were applied, and genes of interest were verified by realtime PCR.

RESULTS

The following genes of lipid metabolism were regulated by CLA: LDLR, FASN, SCD, FADS1 and UCP2 were induced, while ABCA1, CD36 and CA3 were repressed. Transcription factors PPARgamma, NFAT5, CREB5 and EBF1, the adipokine NAMPT, members of the insulin signaling cascade SORBS1 and IGF1 and IL6ST were repressed, while the adipokine THBS1 and GLUT4 involved in insulin signaling were induced. Compared to trans-10,cis-12 CLA and the CLA mixture the cis-9, trans-11 CLA isomer exerted weaker effects. Only CD36 (-1.2 fold) and THBS1 (1.5 fold) were regulated. The CLA effect on expression of PPARgamma and leptin genes depends on the PPARgamma2 genotype.

CONCLUSION

The data suggest that the isomer specific influence of CLA on glucose and lipid metabolism is genotype dependent and at least in part mediated by PPARgamma.

TRIAL REGISTRATION

http://www.controlled-trials.com: ISRCTN91188075.

Disparities in allele frequencies and population differentiation for 101 disease-associated single nucleotide polymorphisms between Puerto Ricans and non-Hispanic whites

Background

Variations in gene allele frequencies can contribute to differences in the prevalence of some common complex diseases among populations. Natural selection modulates the balance in allele frequencies across populations. Population differentiation (F_ST) can evidence environmental selection pressures. Such genetic information is limited in Puerto Ricans, the second largest Hispanic ethnic group in the US, and a group with high prevalence of chronic disease. We determined allele frequencies and population differentiation for 101 single nucleotide polymorphisms (SNPs) in 30 genes involved in major metabolic and disease-relevant pathways in Puerto Ricans (n = 969, ages 45–75 years) and compared them to similarly aged non-Hispanic whites (NHW) (n = 597).

Results

Minor allele frequency (MAF) distributions for 45.5% of the SNPs assessed in Puerto Ricans were significantly different from those of NHW. Puerto Ricans carried risk alleles in higher frequency and protective alleles in lower frequency than NHW. Patterns of population differentiation showed that Puerto Ricans had SNPs with exceptional F_ST values in intronic, non-synonymous and promoter regions. NHW had exceptional F_ST values in intronic and promoter region SNPs only.

Conclusion

These observations may serve to explain and broaden studies on the impact of gene polymorphisms on chronic diseases affecting Puerto Ricans.

Interação entre gene e nutriente e sua associação à obesidade e ao diabetes melito

A genômica nutricional avalia o efeito da variação genética na interação entre dieta e doenças crônicas. O objetivo deste manuscrito foi revisar os principais polimorfismos associados à obesidade, ao diabetes melito e também aos fatores da dieta. As principais interações entre polimorfismos genéticos e dieta foram: para obesidade: interleucina-6 (IL-6) com consumo energético; receptor ativado por proliferador de peroxissoma gama 2 (PPAR-gama2) e fat mass and obesity associated (FTO) com consumo de gorduras; receptor β-adrenérgico 2 (ADRB2) e receptor da melanocortina-4 (MCR4) com consumo de carboidratos; para perda de peso: proteínas desacopladoras (UCPs) com restrição calórica; para leptinemia: receptor da leptina (LEPR) com restrição calórica; para diabetes melito: PPAR-gama2 com consumo de gordura; para hipertrigliceridemia: proteína transportadora de ácidos graxos 2 (FABP2) com consumo de gordura. Os dados apresentados sugerem que a genômica nutricional é importante ao desenvolvimento da obesidade e do diabetes melito.