Bta-miR-130a/b regulates preadipocyte differentiation by targeting PPARG and CYP2U1 in beef cattle

Deposition of intramuscular fat (IMF) is one of the most important traits for the evaluation of beef carcass quality grade. MicroRNA (miRNA) is an endogenous non-coding RNA that can play a role in the post-transcriptional regulation of mammalian preadipocyte differentiation. Previously, we identified that bta-miR-130a regulates milk fat biosynthesis by targeting PPARG mRNA. However, the role of miR-130 in the regulation of bovine adipocyte differentiation remains unknown. In this study, we found that overexpression of bta-miR-130a/b led to significantly decreased cellular triacylglycerol (TAG) levels during adipogenesis process as well as reduced lipid droplet formation. In contrast, the inhibition of bta-miR-130a/b resulted in larger lipid droplets and TAG accumulation. In addition, overexpression of bta-miR-130a/b inhibited the expression of adipocyte differentiation-related genes, including PPARG, C/EBPα, C/EBPβ, FABP4, LPIN1, and LPL. Western blot analysis verified qPCR results on the expression of PPARG and CYP2U1. A luciferase reporter assay further verified bta-miR-130a/b significantly affects PPARG and CYP2U1 expression by directly binding to their 3'-untranslated regions (UTR). We conducted in vitro rescue assay to confirm that bta-miR-130a/b affect bovine adipocyte differentiation by targeting PPARG and CYP2U1. This study shows that bta-miR-130a and bta-miR-130b play similar roles in the regulation of adipocyte differentiation in beef muscles by targeting the 3'UTR of PPARG and CYP2U1. Our result provides a reference for illustrating how noncoding RNAs affects beef quality traits in cattle.

Relationship of PPARG, PPARGC1A, and PPARGC1B polymorphisms with susceptibility to hepatocellular carcinoma in an eastern Chinese Han population

Background

PPARG, PPARGC1A, and PPARGC1B polymorphisms may be implicated in the development of cancer.

Participants and methods

In this study, we selected PPARG rs1801282 C>G and rs3856806 C>T, PPARGC1A rs2970847 C>T, and PPARGC1B rs7732671 G>C and rs17572019 G>A single-nucleotide polymorphisms to explore the relationship between these polymorphisms and hepatocellular carcinoma (HCC) risk. A total of 584 HCC patients and 923 controls were enrolled.

Results

We found that PPARG rs1801282 C>G polymorphism was correlated with a decreased susceptibility of HCC (CG vs CC, adjusted OR 0.47, 95% CI 0.27-0.82, P=0.007; CG/GG vs CC, adjusted OR 0.52, 95% CI 0.31-0.88, P=0.015). However, PPARG rs3856806 C>T polymorphism was a risk factor for HCC (TT vs CC, adjusted OR 2.33, 95% CI 1.25-4.36, P=0.008; TT vs CT/CC, adjusted OR 2.26, 95% CI 1.22-4.17, P=0.010). In a subgroup analysis by chronic hepatitis B virus (HBV)-infection status, age, sex, alcohol use, and smoking status, a significant association between PPARG rs1801282 C>G polymorphism and a decreased risk of HCC in male, ≥53 years, never-smoking, never-drinking, and nonchronic HBV-infection-status subgroups was found. However, we found PPARG rs3856806 C>T polymorphism increased the risk of HCC in never-smoking, never-drinking, and nonchronic HBV-infection-status subgroups. Haplotype-comparison analysis indicated that C_rs1801282T_rs3856806C_rs2970847G_rs7732671G_rs17572019, C_rs1801282T_rs3856806T_rs2970847G_rs7732671G_rs17572019, and C_rs1801282C_rs3856806C_rs2970847C_rs7732671A_rs17572019 haplotypes increased the risk of HCC. PPARG C_rs1801282T_rs3856806 and G_rs1801282C_rs3856806 haplotypes also influenced the risk of HCC.

Conclusion

In conclusion, our findings suggest PPARG polymorphisms may influence the susceptibility of HCC. The PPARG, PPARGC1A, and PPARGC1B haplotypes might be associated with HCC risk.

A Transcriptional Circuit Filters Oscillating Circadian Hormonal Inputs to Regulate Fat Cell Differentiation

Glucocorticoid and other adipogenic hormones are secreted in mammals in circadian oscillations. Loss of this circadian oscillation pattern correlates with obesity in humans, raising the intriguing question of how hormone secretion dynamics affect adipocyte differentiation. Using live, single-cell imaging of the key adipogenic transcription factors CEBPB and PPARG, endogenously tagged with fluorescent proteins, we show that pulsatile circadian hormone stimuli are rejected by the adipocyte differentiation control system. In striking contrast, equally strong persistent signals trigger maximal differentiation. We identify the mechanism of how hormone oscillations are filtered as a combination of slow and fast positive feedback centered on PPARG. Furthermore, we confirm in mice that flattening of daily glucocorticoid oscillations significantly increases the mass of subcutaneous and visceral fat pads. Together, our study provides a molecular mechanism for why stress, Cushing's disease, and other conditions for which glucocorticoid secretion loses its pulsatility may lead to obesity.

PPARGC1A rs3736265 G>A polymorphism is associated with decreased risk of type 2 diabetes mellitus and fasting plasma glucose level

It has been reported that peroxisome proliferator-activated receptor gamma (PPARG) and peroxisome proliferator-activated receptor gamma co-activator 1 (PPARGC1) family (e.g. PPARGC1A and PPARGC1B) are key agents in the development and pathophysiology of type 2 diabetes mellitus (T2DM). In this study, we designed a case-control study and selected PPARG rs1801282 C>G, PPARG rs3856806 C>T, PPARGC1A rs8192678 C>T, PPARGC1A rs2970847 C>T, PPARGC1A rs3736265 G>A, PPARGC1B rs7732671 G>C and PPARGC1B rs17572019 G>A polymorphisms to assess the relationship between these polymorphisms and T2DM using the SNPscan method. A total of 502 T2DM patients and 784 non-diabetic controls were enrolled. We found that PPARGC1A rs3736265 G>A polymorphism was correlated with a borderline decreased susceptibility of T2DM. In a subgroup analysis by age, sex, alcohol use, smoking status and body mass index, a significantly decreased risk of T2DM in <65 years and female groups was found. Haplotype comparison analysis indicated that CTTCGGG and CTCTGGG haplotypes with the order of PPARG rs1801282 C>G, PPARG rs3856806 C>T, PPARGC1A rs8192678 C>T, PPARGC1A rs2970847 C>T, PPARGC1A rs3736265 G>A, PPARGC1B rs7732671 G>C and PPARGC1B rs17572019 G>A polymorphisms in gene position significantly increased the risk of T2DM. However, CCCCACA haplotype conferred a decreased risk to T2DM. We also found that PPARGC1A rs3736265 A allele decreased the level of fasting plasma glucose (FPG), while increased the level of Triglyceride. In conclusion, Our findings suggest that variants of PPARGC1A rs3736265 G>A polymorphism decrease the level of FPG, improving the expectation of study in individual's prevention strategies to T2DM.

Effect of PPARG on AGEs-induced AKT/MTOR signaling-associated human chondrocytes autophagy

Accumulation of advanced glycation end products (AGEs) in articular cartilage is thought to represent a major risk factor for osteoarthritis development. In this study we aimed to probe the role of AGEs in human chondrocytes and to determine the impact of the peroxisome proliferator-activated receptor-γ (PPARG) on AGEs-induced cell autophagy. Cell viability was measured after human chondrocytes were treated with different concentrations of AGEs with or without the PPARG inhibitor, T0070907, or agonist, pioglitazone. Autophagy activation markers (MAP2LC3, BECN1 and SQSTM1/P62), expression of PPARG and the phosphorylation levels of Akt/MTOR were determined by Western blotting; autophagosome formation was analyzed by transmission electron microscopy (TEM); autophagic flux was detected with mRFP-GFP-LC3 tandem construct. Low doses of AGEs over a short amount of time stimulated chondrocyte proliferation and autophagy by limiting phosphorylation of Akt/MTOR signaling. The addition of PPARG inhibitor T0070907 lead to defective autophagy. High dose and long exposure to AGEs inhibited cell viability and autophagy by increasing phosphorylation levels of Akt/MTOR signaling. The agonist, pioglitazone, was shown to protect cell autophagy in a dose-dependent manner. Our findings suggest AGEs can downregulate PPARG and that PPARG maintains cell viability by activating the Akt/MTOR signaling pathway as well as inducing chondrocyte autophagy.

Specific micro-RNA expression patterns distinguish the basal and luminal subtypes of muscle-invasive bladder cancer

The roles of non-coding RNAs in controlling clinical and biological heterogeneity in bladder cancer remain unclear. We used TCGA's published dataset (n = 405 tumors) as a discovery cohort and created a new validation cohort to define the miRNA expression patterns in the basal and luminal molecular subtypes of muscle-invasive bladder cancer (MIBC). We identified 63 miRNAs by PAM, which optimally identified basal and luminal tumors. The targets of the top luminal miRNAs were activators of EMT (ZEB1, ZEB2) and basal subtype transcription (IL-6, EGFR, STAT3), whereas the targets of the top basal miRNAs were involved in adipogenesis pathways and luminal breast cancer (ERBB2, ERBB3). We also identified a 15-miRNA signature that identified stromally infiltrated basal and luminal MIBCs corresponding to the “cluster IV/immune undifferentiated/claudin-low” and “cluster II/luminal immune” subtypes identified previously, which likely contain samples with higher infiltration rates. Using the 63-miRNA signature, we accurately assigned MIBCs to the basal and luminal subtypes and confirmed that patients with basal tumors had shorter overall survival. The results strongly suggest that miRNAs contribute to the control of the gene expression patterns observed in basal and luminal MIBCs and that they can be used as biomarkers and candidate therapeutic targets.

Interactions Between PPARG and AGTR1 Gene Polymorphisms on the Risk of Hypertension in Chinese Han Population

AIMS

To explore the interactions between PPARG and AGTR1 polymorphisms and their associations with hypertension in the Chinese Han population.

METHODS

Seven single nucleotide polymorphisms (SNPs) of the PPARG gene and five SNPs of the AGTR1 gene were selected and genotyped in 1591 unrelated Chinese Han adults. The SNPAssoc package of R was used to analyze the associations between the selected SNPs and hypertension. The potential gene-gene interactions between PPARG and AGTR1 genes were tested by model-based multifactor dimensionality reduction (MB-MDR).

RESULTS

The frequencies of the C allele of rs3856806 and the G allele of rs13433696 in the PPARG gene were significantly lower in hypertensive subjects, whereas the A allele of rs9817428 in the PPARG gene was much higher in hypertensives. In addition, individuals with T allele of rs2933249 in the AGTR1 gene displayed a significantly decreased risk of hypertension. MB-MDR analyses suggested that the two-locus model (rs9817428 and rs2933249) and the three-locus model (rs9817428, rs3856806, and rs2933249) were significantly associated with a decreased risk of hypertension. Moreover, among the eight SNPs not individually associated with hypertension (rs12631819, rs2920502, rs1175543, and rs2972164 in the PPARG gene, and rs2638360, rs1492100, rs5182, and rs275646 in the AGTR1 gene), the two-locus model involving rs12631819 and rs5182 demonstrated increased susceptibility to hypertension, and the five-locus model involving rs12631819, rs2920502, rs2972164, rs5182, and rs2638360 demonstrated a significantly decreased risk of hypertension.

CONCLUSION

Polymorphisms in both the PPARG and AGTR1 genes were found to be significantly associated with hypertension. Moreover, there were significant gene-gene interactions identified between the PPARG and AGTR1 genes in relation to hypertension susceptibility in the Chinese Han population.

Machine learning shows association between genetic variability in PPARG and cerebral connectivity in preterm infants

Preterm birth affects 11% of births globally; 35% of infants develop long-term neurocognitive problems, and prematurity leads to the loss of 75 million disability adjusted life years per annum worldwide. Imaging studies have shown that these infants have extensive alterations in brain development, but little is known about the molecular or cellular mechanisms involved. This imaging genetics study found a strong association between abnormal cerebral connectivity and variability in the PPARG gene, implicating PPARG signaling in abnormal white-matter development in preterm infants and suggesting a tractable new target for therapeutic research.

Preterm infants show abnormal structural and functional brain development, and have a high risk of long-term neurocognitive problems. The molecular and cellular mechanisms involved are poorly understood, but novel methods now make it possible to address them by examining the relationship between common genetic variability and brain endophenotype. We addressed the hypothesis that variability in the Peroxisome Proliferator Activated Receptor (PPAR) pathway would be related to brain development. We employed machine learning in an unsupervised, unbiased, combined analysis of whole-brain diffusion tractography together with genomewide, single-nucleotide polymorphism (SNP)-based genotypes from a cohort of 272 preterm infants, using Sparse Reduced Rank Regression (sRRR) and correcting for ethnicity and age at birth and imaging. Empirical selection frequencies for SNPs associated with cerebral connectivity ranged from 0.663 to zero, with multiple highly selected SNPs mapping to genes for PPARG (six SNPs), ITGA6 (four SNPs), and FXR1 (two SNPs). SNPs in PPARG were significantly overrepresented (ranked 7–11 and 67 of 556,000 SNPs; P < 2.2 × 10⁻⁷), and were mostly in introns or regulatory regions with predicted effects including protein coding and nonsense-mediated decay. Edge-centric graph-theoretic analysis showed that highly selected white-matter tracts were consistent across the group and important for information transfer (P < 2.2 × 10⁻¹⁷); they most often connected to the insula (P < 6 × 10⁻¹⁷). These results suggest that the inhibited brain development seen in humans exposed to the stress of a premature extrauterine environment is modulated by genetic factors, and that PPARG signaling has a previously unrecognized role in cerebral development.

The relationship between IGF2BP2 and PPARG polymorphisms and susceptibility to esophageal squamous-cell carcinomas in the eastern Chinese Han population

The aim of this case–control study was to assess whether PPARG and IGF2BP2 polymorphisms confer susceptibility to esophageal squamous-cell carcinoma (ESCC). A total of 507 patients pathologically confirmed for ESCC and 1,496 age-, sex-, and residence-matched healthy individuals were enrolled. The PPARG rs1801282 C>G and rs3856806 C>T and IGF2BP2 rs1470579 A>C and rs4402960 G>T polymorphisms were selected and genotyped by SNPscan genotyping assays. Multivariable logistic analysis suggested that the PPARG rs3856806 C>T polymorphism might increase the risk of ESCC. In different stratified analyses, there were significant associations between PPARG rs3856806 C>T and risk of ESCC in female, never-smoking, drinking, and never-drinking subgroups. In addition, we also found that PPARG rs1801282 C>G increased ESCC risk in the never-smoking subgroup. There was significant difference in C_rs1470579G_rs4402960C_rs1801282C_rs3856806-haplotype distribution among ESCC cases and control subjects. In conclusion, our findings highlight that PPARG rs1801282 C>G and rs3856806 C>T polymorphisms are candidates for susceptibility to ESCC in the eastern Chinese Han population. The C_rs1470579G_rs4402960C_rs1801282C_rs3856806 haplotype is associated with susceptibility to ESCC.

Bladder-cancer-associated mutations in RXRA activate peroxisome proliferator-activated receptors to drive urothelial proliferation

RXRA regulates transcription as part of a heterodimer with 14 other nuclear receptors, including the peroxisome proliferator-activated receptors (PPARs). Analysis from TCGA raised the possibility that hyperactive PPAR signaling, either due to PPAR gamma gene amplification or RXRA hot-spot mutation (S427F/Y) drives 20-25% of human bladder cancers. Here, we characterize mutant RXRA, demonstrating it induces enhancer/promoter activity in the context of RXRA/PPAR heterodimers in human bladder cancer cells. Structure-function studies indicate that the RXRA substitution allosterically regulates the PPAR AF2 domain via an aromatic interaction with the terminal tyrosine found in PPARs. In mouse urothelial organoids, PPAR agonism is sufficient to drive growth-factor-independent growth in the context of concurrent tumor suppressor loss. Similarly, mutant RXRA stimulates growth-factor-independent growth of Trp53/Kdm6a null bladder organoids. Mutant RXRA-driven growth of urothelium is reversible by PPAR inhibition, supporting PPARs as targetable drivers of bladder cancer.

PPARG c.1347C>T polymorphism is associated with cancer susceptibility: from a case-control study to a meta-analysis

Recently, several studies suggested that PPARG c.1347C>T polymorphism was correlated with cancer risk. However, past results remained controversial. In this study, we performed a case-control study on the relationship of PPARG c.1347C>T polymorphism with risk of non-small cell lung cancer (NSCLC) and subsequently carried out a meta-analysis to further assess the association between PPARG c.1347C>T and overall cancer. In our case-control study, after adjusting by age, sex, body mass index (BMI), smoking and drinking, a tendency to increased NSCLC risk was noted (CT/TT vs. CC: adjusted OR, 1.21; 95% CI, 0.97–1.51; P = 0.097). In the meta-analysis, we found a significant association between PPARG c.1347C>T polymorphism and overall cancer risk (T vs. C: OR, 1.13; 95% CI, 1.03–1.23; P = 0.006; TT vs. CC: OR, 1.29; 95% CI, 1.07–1.56; P = 0.008, CT/TT vs. CC: OR, 1.11; 95% CI, 1.02–1.21; P = 0.014 and TT vs. CT/CC: OR, 1.26; 95% CI, 1.04–1.52; P = 0.016). In a subgroup analysis by ethnicity, evidence of significant association between PPARG c.1347C>T polymorphism and cancer risk was found among Asians and mixed populations. In a subgroup analysis by cancer type, PPARG c.1347C>T polymorphism was associated with risk of esophageal cancer and glioblastoma. In addition, in a subgroup analysis by origin of cancer cell, evidence of significant association between PPARG c.1347C>T polymorphism and cancer risk was also found among epithelial tumor. In conclusion, the findings indicate PPARG c.1347C>T polymorphism may increase the susceptibility of cancer.

Can half-marathon affect overall health? The yin-yang of sport

Physical activity improves overall health and counteracts metabolic pathologies. Adipose tissue and bone are important key targets of exercise; the prevalence of diseases associated with suboptimal physical activity levels has increased in recent times as a result of lifestyle changes. Mesenchymal stem cells (MSCs) differentiation in either osteogenic or adipogenic lineage is regulated by many factors. Particularly, the expression of master genes such as RUNX2 and PPARγ2 is essential for MSC commitment to osteogenic or adipogenic differentiation, respectively. Besides various positive effects on health, some authors have reported stressful outcomes as a consequence of endurance in physical activity. We looked for further clues about MSCs differentiation and serum proteins modulation studying the effects of half marathon in runners by means of gene expression analyses and a proteomic approach. Our results demonstrated an increase in osteogenic commitment and a reduction in adipogenic commitment of MSCs. In addition, for the first time we have analyzed the proteomic profile changes in runners after half-marathon activity in order to survey the related systemic adjustments. The shotgun proteomic approach, performed through the immuno-depletion of the 14 most abundant serum proteins, allowed the identification of 23 modulated proteins after the half marathon. Interestingly, proteomic data showed the activation of both inflammatory response and detoxification process. Moreover, the involvement of pathways associated to immune response, lipid transport and coagulation, was elicited. Notably, positive and negative effects may be strictly linked. Data are available via ProteomeXchange with identifier PXD006704.

SIGNIFICANCE

We describe gene expression and proteomic studies aiming to an in-depth understanding of half-marathon effects on bone and adipogenic differentiation as well as biological phenomena involved in sport activity. We believe that this novel approach suggests the physical effects on overall health and show the different pathways involved during half marathon. Contents of the paper have not been published or submitted for publication elsewhere. The authors declare no conflict of interest.

Association of PPARG rs 1801282 C>G polymorphism with risk of colorectal cancer: from a case-control study to a meta-analysis

The functional single nucleotide polymorphisms in peroxisome proliferator-activated receptor gamma (PPARG) gene were predicted to be correlated with the susceptibility of colorectal cancer (CRC). The aim of the present study was to explore the relationship between PPARG rs1801282 C>G polymorphism and the risk of CRC. First, we conducted a case-control study with 387 CRC cases and 1,536 controls. We used the SNPscan method to determine the genotypes of PPARG rs1801282 C>G polymorphism. We found PPARG rs1801282 C>G polymorphism had a tendency of decreased risk to CRC risk (CG vs. CC: adjusted OR, 0.67, 95% CI = 0.43–1.04 for CG vs. CC, P = 0.073; GG vs. CC: adjusted OR, 0.68; 95% CI, 0.44–1.05; P = 0.078). The stratified analysis revealed PPARG rs1801282 C>G polymorphism also had a tendency of decreased risk to colon cancer (CG vs. CC: adjusted OR = 0.54, 95% CI = 0.27–1.08, P = 0.083). The results of subsequent meta-analysis suggested that PPARG rs1801282 C>G polymorphism might be a protective factor for CRC, especially in Asians, colon cancer and rectum cancer subgroups. In conclusion, our study indicates that PPARG rs1801282 C>G polymorphism might decrease the risk of overall CRC. Larger sample size and well-designed case-control studies are needed to confirm the potential association.

Clinical presentations, metabolic abnormalities and end-organ complications in patients with familial partial lipodystrophy

OBJECTIVE

Familial partial lipodystrophy (FPLD) is a rare genetic disorder characterized by partial lack of subcutaneous fat.

METHODS

This multicenter prospective observational study included data from 56 subjects with FPLD (18 independent Turkish families). Thirty healthy controls were enrolled for comparison.

RESULTS

Pathogenic variants of the LMNA gene were determined in nine families. Of those, typical exon 8 codon 482 pathogenic variants were identified in four families. Analysis of the LMNA gene also revealed exon 1 codon 47, exon 5 codon 306, exon 6 codon 349, exon 9 codon 528, and exon 11 codon 582 pathogenic variants. Analysis of the PPARG gene revealed exon 3 p.Y151C pathogenic variant in two families and exon 7 p.H477L pathogenic variant in one family. A non-pathogenic exon 5 p.R215Q variant of the LMNB2 gene was detected in another family. Five other families harbored no mutation in any of the genes sequenced. MRI studies showed slightly different fat distribution patterns among subjects with different point mutations, though it was strikingly different in subjects with LMNA p.R349W pathogenic variant. Subjects with pathogenic variants of the PPARG gene were associated with less prominent fat loss and relatively higher levels of leptin compared to those with pathogenic variants in the LMNA gene. Various metabolic abnormalities associated with insulin resistance were detected in all subjects. End-organ complications were observed.

CONCLUSION

We have identified various pathogenic variants scattered throughout the LMNA and PPARG genes in Turkish patients with FPLD. Phenotypic heterogeneity is remarkable in patients with LMNA pathogenic variants related to the site of missense mutations. FPLD, caused by pathogenic variants either in LMNA or PPARG is associated with metabolic abnormalities associated with insulin resistance that lead to increased morbidity.

Anti-adipogenic effects of Tropaeolum majus (nasturtium) ethanol extract on 3T3-L1 cells

Background: Edible flowers, Tropaeolum majus has been used as a disinfectant and an antibiotic, and for wound healing, but the anti-obesity effects of this plant have not been reported previously Objective: We investigated the anti-adipogenic effects of T. majus ethanol extract (TME) on 3T3-L1 cells. Design: 3T3-L1 cells were differentiated in the presence of different concentrations of TME. Lipid accumulation levels were determined using Oil-Red O staining and a triglyceride content assay. Changes in the expression of proteins related to adipocyte differentiation in 3T3-L1 cells were determined by SDS-PAGE and western blotting. Results: The highest inhibition of lipid accumulation was observed at a TME concentration of 300 µg/mL. Additionally, TME concentrations ranging from 20 µg/mL to 500 µg/mL led to a decrease in the expression of adipocyte differentiation regulators, peroxisome proliferator-activated receptor γ, CCAAT element binding protein α, and sterol regulatory element binding transcription factor 1. This decrease was shown to be concentration-dependent. Discussion: Taken together, the results of this study demonstrate that TME inhibits lipid accumulation and reduces the expression PPARG, CEBPA, and SREBF1, which regulate adipocyte differentiation in 3T3-L1 cells. Conclusions: TME may be a potential novel therapeutic agent for the prevention and treatment of obesity.

Association of the Pro12Ala Polymorphism with the Metabolic Parameters in Women with Polycystic Ovary Syndrome

AIM:

To investigate the association of peroxisome proliferator-activated receptor gamma (PPARG) Pro12Ala polymorphism with polycystic ovary syndrome (PCOS) and its effect on the metabolic parameters in PCOS women.

METHODS:

The study used PCR to identify the presence of the PPARG Pro12Ala polymorphism in 100 PCOS women and 120 age-matched healthy women. All participants were subjected to anthropometry, biochemical and metabolic evaluation.

RESULTS:

Significant difference in the genotypes distributions of PPARG Pro12Ala polymorphism was observed among PCOS women and controls (p = 0.03). The frequency of the polymorphic allele Ala was significantly higher in PCOS cases than that in the controls (OR = 2.01, p = 0.01). The carries of the variant allele Ala in PCOS women showed significant higher values in body mass index (BMI), systolic and diastolic blood pressure, waist circumference, waist to hip ratio, sum of skin folds, fasting blood glucose, fasting blood insulin, HOMA-IR, fasting triglycerides, total cholesterol and low-density lipoprotein than non-carriers.

CONCLUSION:

The PPARG Pro12Ala polymorphism might contribute to the risk of PCOS and abnormal metabolic parameters and could be considered as a biomarker for early diagnosis and clinic prediction of metabolic complications.

Genetic factors related with early onset of osteonecrosis of the jaw in patients with multiple myeloma under zoledronic acid therapy

Specific genetic polymorphisms (SNPs) have been correlated with the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in small series. We screened 140 myeloma patients (36 patients with and 104 without BRONJ) for the presence of previously identified SNPs in PPARG and CYP2C8 genes. All the patients received exclusively zolendronic acid (ZA) therapy and were followed prospectively for BRONJ. SNPs in both genes were associated with a higher risk of development of early BRONJ, occurring within less than 2 years of ZA therapy (59% vs. 16%, p = .022 for PPARG and 29% vs. 7%, p = .07 for CYP2C8) and a shorter time to develop BRONJ (59% versus 12%, p = .011 for PPARG and 29% versus 0% at 2 years, p = .037 for CYP2C8), independently of indices of poor oral hygiene. Thus, although preliminary, our data indicate that the presence of SNPs in PPARG and CYP2C8 genes may be associated with increased risk of early BRONJ.

miR-27a controls triacylglycerol synthesis in bovine mammary epithelial cells by targeting peroxisome proliferator-activated receptor gamma

Growing evidence has revealed that microRNA are central elements in milk fat synthesis in mammary epithelial cells. A negative regulator of adipocyte fat synthesis, miR-27a has been reported to be involved in the regulation of milk fat synthesis in goat mammary epithelial cells; however, the regulatory role of miR-27a in bovine milk fat synthesis remains unclear. In the present study, primary bovine mammary epithelial cells (BMEC) were harvested from mid-lactation cows and cultured in Dulbecco's modified Eagle's medium/F-12 medium with 10% fetal bovine serum, 5 μg/mL of insulin, 1 μg/mL of hydrocortisone, 2 μg/mL of prolactin, 1 μg/mL of progesterone, 100 U/mL of penicillin, and 100 μg/mL of streptomycin. We found that the overexpression of miR-27a significantly suppressed lipid droplet formation and decreased the cellular triacylglycerol (TAG) levels, whereas inhibition of miR-27a resulted in a greater lipid droplet formation and TAG accumulation in BMEC. Meanwhile, overexpression of miR-27a inhibited mRNA expression of peroxisome proliferator-activated receptor gamma (PPARG), CCAAT/enhancer-binding protein beta (C/EBPβ), perilipin 2 (PLIN2), and fatty acid binding protein 3 (FABP3), whereas miR-27a downregulation increased PPARG, C/EBPβ, FABP3, and CCAAT enhancer binding protein alpha (C/EBPα) mRNA expression. Furthermore, Western blot analysis revealed the protein level of PPARG in miR-27a mimic and inhibitor transfection groups to be consistent with the mRNA expression response. Moreover, luciferase reporter assays verified that PPARG was the direct target of miR-27a. In summary, these results indicate that miR-27a has the ability to control TAG synthesis in BMEC via targeting PPARG, suggesting that miR-27a could potentially be used to improve beneficial milk components in dairy cows.

Obesity-related genetic polymorphisms and adiposity indices in a young Italian population

Pediatric obesity develops when a complex biological predisposition collides with an obesogenic environment. To further elucidate the role of genetics in obesity onset, we performed a candidate-gene association study in a young and sportive Italian population by testing the association of functional polymorphisms in ACE (rs4646994), FTO (rs9939609), MC4R (rs17782313) and PPARG (rs1801282) genes with body mass index (BMI) and waist-to-height ratio (WHtR). We also tested the combinations of identified risk genotypes and epistatic interactions among them to determine the existence of cumulative effects in predicting the predisposition to gain weight. Our results confirm a significant direct influence of MC4R rs17782313 and PPARG rs1801282 on body composition, that is, minor allele homozygotes showed significantly higher BMI (rs17782313, β = 1.258, P = 0.031; rs1801282, β = 6.689, P = 1.2 × 10^-4 ) and WHtR (rs17782313, β = 0.021, P = 0.005; rs1801282, β = 0.069, P = 0.003) values. Moreover, by leveraging multifactor dimensionality reduction and general linear model (GLM) approaches we identified an epistatic interaction between ACE and MC4R, where heterozygosity at ACE rs4646994 seems to protect from the unfavorable predisposition to gain weight given by C/C genotype at MC4R rs17782313 (GLM, P = 0.004). In conclusion, to clarify the role of genetics in multifactorial diseases remains a difficult goal, even for the most investigated polymorphisms and in controlled populations. Further studies on epistasis and gene-gene interaction will help to elucidate this complex scenario. © 2017 IUBMB Life, 69(2):98-105, 2017.

Gene- Gene Interaction between PPARG and APOE Gene on Late-Onset Alzheimer's Disease: A Case- Control Study in Chinese Han Population

AIMS

The aim was to investigate the impact of PPARG and APOE gene single nucleotide polymorphisms (SNPs) and additional gene- gene interaction on late-onset Alzheimer's disease (LOAD) risk based on Chinese Han population.

METHODS

A total of 928 participants (466 males, 462 females), with a mean age of 81.3 ± 16.4 years old, were included in the study, including 460 LOAD patients and 468 normal controls participants. Logistic regression was performed to investigate association between SNP and LOAD risk and generalized multifactor dimensionality reduction (GMDR) was used to analysis the gene-gene interaction.

RESULTS

Logistic regression analysis showed that LOAD risk was significantly higher in carriers of G allele of the rs405509 polymorphism than those with AA (AG+ GG versus AA, adjusted OR (95%CI) =1.54(1.20-1.89), and higher in carriers of G allele of the rs1805192 polymorphism than those with CC (CG+ GG versus CC, adjusted OR (95%CI) =1.32(1.16-2.43). We also found that there was a potential gene-gene interaction between rs405509 and rs1805192. Participants with AG or GG of rs405509 and CG or GG of rs1805192 genotype have the highest AD risk, compared to participants with AA of rs405509 and CC of rs1805192 genotype, OR (95%CI) was 2.62(1.64 -3.58), after covariates adjustment.

CONCLUSIONS

G allele of the rs405509 of APOE and G allele of the rs1805192 of PPAR G polymorphism were associated with increased LOAD risk, and participants with AG or GG of rs405509 and CG or GG of rs1805192 genotype have the highest AD risk.

Editor's Highlight: Screening ToxCast Prioritized Chemicals for PPARG Function in a Human Adipose-Derived Stem Cell Model of Adipogenesis

The developmental origins of obesity hypothesis posits a multifaceted contribution of factors to the fetal origins of obesity and metabolic disease. Adipocyte hyperplasia in gestation and early childhood may result in predisposition for obesity later in life. Rodent in vitro and in vivo studies indicate that some chemicals may directly affect adipose progenitor cell differentiation, but the human relevance of these findings is unclear. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARG) is the master regulator of adipogenesis. Human adipose-derived stem cells (hASC) isolated from adipose tissue express endogenous isoforms of PPARG and represent a biologically relevant cell-type for evaluating activity of PPARG ligands. Here, a multi-endpoint approach based on a phenotypic adipogenesis assay was applied to screen a set of 60 chemical compounds identified in ToxCast Phase I as PPARG active (49) or inactive (11). Chemicals showing activity in the adipogenesis screen were further evaluated in a series of 4 orthogonal assays representing 7 different key events in PPARG-dependent adipogenesis, including gene transcription, protein expression, and adipokine secretion. An siRNA screen was also used to evaluate PPARG-dependence of the adipogenesis phenotype. A universal concentration-response design enabled inter-assay comparability and implementation of a weight-of-evidence approach for bioactivity classification. Collectively, a total of 14/49 (29%) prioritized chemicals were identified with moderate-to-strong activity for human adipogenesis. These results provide the first integrated screening approach of prioritized ToxCast chemicals in a human stem cell model of adipogenesis and provide insight into the capacity of PPARG-activating chemicals to modulate early life programming of adipose tissue.

Sleeping Beauty screen reveals Pparg activation in metastatic prostate cancer

Prostate cancer (CaP) is the most common adult male cancer in the developed world. The paucity of biomarkers to predict prostate tumor biology makes it important to identify key pathways that confer poor prognosis and guide potential targeted therapy. Using a murine forward mutagenesis screen in a Pten-null background, we identified peroxisome proliferator-activated receptor gamma (Pparg), encoding a ligand-activated transcription factor, as a promoter of metastatic CaP through activation of lipid signaling pathways, including up-regulation of lipid synthesis enzymes [fatty acid synthase (FASN), acetyl-CoA carboxylase (ACC), ATP citrate lyase (ACLY)]. Importantly, inhibition of PPARG suppressed tumor growth in vivo, with down-regulation of the lipid synthesis program. We show that elevated levels of PPARG strongly correlate with elevation of FASN in human CaP and that high levels of PPARG/FASN and PI3K/pAKT pathway activation confer a poor prognosis. These data suggest that CaP patients could be stratified in terms of PPARG/FASN and PTEN levels to identify patients with aggressive CaP who may respond favorably to PPARG/FASN inhibition.

Distinct gene regulatory programs define the inhibitory effects of liver X receptors and PPARG on cancer cell proliferation

Background

The liver X receptors (LXRs, NR1H2 and NR1H3) and peroxisome proliferator-activated receptor gamma (PPARG, NR1C3) nuclear receptor transcription factors (TFs) are master regulators of energy homeostasis. Intriguingly, recent studies suggest that these metabolic regulators also impact tumor cell proliferation. However, a comprehensive temporal molecular characterization of the LXR and PPARG gene regulatory responses in tumor cells is still lacking.

Methods

To better define the underlying molecular processes governing the genetic control of cellular growth in response to extracellular metabolic signals, we performed a comprehensive, genome-wide characterization of the temporal regulatory cascades mediated by LXR and PPARG signaling in HT29 colorectal cancer cells. For this analysis, we applied a multi-tiered approach that incorporated cellular phenotypic assays, gene expression profiles, chromatin state dynamics, and nuclear receptor binding patterns.

Results

Our results illustrate that the activation of both nuclear receptors inhibited cell proliferation and further decreased glutathione levels, consistent with increased cellular oxidative stress. Despite a common metabolic reprogramming, the gene regulatory network programs initiated by these nuclear receptors were widely distinct. PPARG generated a rapid and short-term response while maintaining a gene activator role. By contrast, LXR signaling was prolonged, with initial, predominantly activating functions that transitioned to repressive gene regulatory activities at late time points.

Conclusions

Through the use of a multi-tiered strategy that integrated various genomic datasets, our data illustrate that distinct gene regulatory programs elicit common phenotypic effects, highlighting the complexity of the genome. These results further provide a detailed molecular map of metabolic reprogramming in cancer cells through LXR and PPARG activation. As ligand-inducible TFs, these nuclear receptors can potentially serve as attractive therapeutic targets for the treatment of various cancers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-016-0328-6) contains supplementary material, which is available to authorized users.

PPARG gene C161T CT/TT associated with lower blood lipid levels and ischemic stroke from large-artery atherosclerosis in a Han population in Guangdong

OBJECTIVE

Peroxisome proliferator-activated receptor gamma (PPARG) is a transcription factor involved in atherosclerosis and related diseases. In this study, we aimed to investigate whether PPARG C161T was associated with lipid levels and large-artery atherosclerosis (LAA) ischemic stroke in a Han Chinese population in Guangdong province.

METHODS

The genotype PPARG C161T in 149 LAA ischemic stroke patients and 125 healthy controls was examined by polymerase chain reaction-restriction fragment length polymorphism (RFLP) assay. Associations with LAA ischemic stroke were analyzed for PPARG C161T genotype, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), and a logistic regression analysis was performed to identify risk factors for LAA ischemic stroke.

RESULTS

The frequency of CC was higher than that of CT + TT and was significantly associated with LAA ischemic stroke. In both the LAA and control groups, TC and LDL-C levels were significantly higher in the CC type than the CT + TT, but TG and HDL-C levels were comparable. The only verified independent risk factors for LAA ischemic stroke were ischemic heart disease (OR: 2.784, 95% CI: 1.377-5.632; p = 0.004) and systolic blood pressure (OR: 1.014, 95% CI: 1.001-1.026; p = 0.029); the PPARG C161T allele was not independently associated with an increased risk of LAA ischemic stroke (OR = 0.697, 95% CI: 0.372-1.305; p = 0.260).

CONCLUSION

In this Han population, PPARG C161T CT/TT was associated with LAA ischemic stroke and lower levels of blood TC and LDL-C, but was not an independent risk factor for LAA ischemic stroke.

Alcohol-related breast cancer in postmenopausal women - effect of CYP19A1, PPARG and PPARGC1A polymorphisms on female sex-hormone levels and interaction with alcohol consumption and NSAID usage in a nested case-control study and a randomised controlled trial

Background

Alcohol consumption is associated with increased risk of breast cancer (BC), and the underlying mechanism is thought to be sex-hormone driven. In vitro and observational studies suggest a mechanism involving peroxisome proliferator-activated receptor gamma (PPARγ) in a complex with peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) and interaction with aromatase (encoded by CYP19A1). Use of non-steroidal anti-inflammatory drugs (NSAID) may also affect circulating sex-hormone levels by modifying PPARγ activity.

Methods

In the present study we assessed whether genetic variation in CYP19A1 is associated with risk of BC in a case-control study group nested within the Danish “Diet, Cancer and Health” cohort (n_cases = 687 and n_controls = 687) and searched for gene-gene interaction between CYP19A1 and PPARGC1A, and CYP19A1 and PPARG, and gene-alcohol and gene-NSAID interactions. Association between the CYP19A1 polymorphisms and hormone levels was also examined among 339 non-HRT users. Incidence rate ratios were calculated based on Cox’ proportional hazards model. Furthermore, we performed a pilot randomised controlled trial to determine the effect of the PPARG Pro¹²Ala polymorphism and the PPARγ stimulator Ibuprofen on sex-hormone levels following alcohol intake in postmenopausal women (n = 25) using linear regression.

Results

Genetic variations in CYP19A1 were associated with hormone levels (estrone: P_rs11070844 = 0.009, estrone sulphate: P_rs11070844 = 0.01, P_rs749292 = 0.004, P_rs1062033 = 0.007 and P_rs10519297 = 0.03, and sex hormone-binding globulin (SHBG): P_rs3751591 = 0.03) and interacted with alcohol intake in relation to hormone levels (estrone sulphate: P_{interaction/rs2008691} = 0.02 and P_{interaction/rs1062033=} 0.03, and SHBG: P_{interaction/rs11070844} = 0.03). CYP19A1/rs3751591 was both associated with SHBG levels (P = 0.03) and with risk of BC (Incidence Rate Ratio = 2.12; 95 % Confidence Interval: 1.02–4.43) such that homozygous variant allele carriers had increased levels of serum SHBG and were at increased risk of BC. Acute intake of alcohol decreased blood estrone (P = <0.0001), estrone sulphate (P = <0.0001), and SHBG (P = 0.009) levels, whereas Ibuprofen intake and PPARG Pro¹²Ala genotype had no effect on hormone levels.

Conclusions

Our results suggest that genetically determined variation in CYP19A1 is associated with differences in sex hormone levels. However, the genetically determined differences in sex hormone levels were not convincingly associated with BC risk. The results therefore indicate that the genetically determined variation in CYP19A1 contributes little to BC risk and to alcohol-mediated BC risk.

Trial registration

NCT02463383, June 3, 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2317-y) contains supplementary material, which is available to authorized users.