Principal component analysis of adipose tissue gene expression of lipogenic and adipogenic factors in obesity.

OBJECTIVE: A better understanding of mechanisms regulating lipogenesis and adipogenesis is needed to overcome the obesity pandemic. We aimed to study the relationship of the transcript levels of peroxisome proliferator activator receptor γ (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBP-α), liver X receptor (LXR), sterol regulatory element-binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) from obese and normal-weight women with a variety of anthropometric indices, metabolic and biochemical parameters, and insulin resistance. METHODS: Real-time PCR was done to evaluate the transcript levels of the above-mentioned genes in VAT and SAT from all participants. RESULTS: Using principal component analysis (PCA) results, two significant principal components were identified for adipogenic and lipogenic genes in SAT (SPC1 and SPC2) and VAT (VPC1 and VPC2). SPC1 was characterized by relatively high transcript levels of SREBP1c, PPARγ, FAS, and ACC. However, the second pattern (SPC2) was associated with C/EBPα and LXR α mRNA expression. VPC1 was characterized by transcript levels of SREBP1c, FAS, and ACC. However, the VPC2 was characterized by transcript levels of C/EBPα, LXR α, and PPARγ. Pearson's correlation analysis showed that unlike SPC2, which disclosed an inverse correlation with body mass index, waist and hip circumference, waist to height ratio, visceral adiposity index, HOMA-IR, conicity index, lipid accumulation product, and weight-adjusted waist index, the VPC1 was positively correlated with above-mentioned obesity indices. CONCLUSION: This study provided valuable data on multiple patterns for adipogenic and lipogenic genes in adipose tissues in association with a variety of anthropometric indices in obese subjects predicting adipose tissue dysfunction and lipid accumulation.

Adipose tissue gene expression of long non-coding RNAs; MALAT1, TUG1 in obesity: is it associated with metabolic profile and lipid homeostasis-related genes expression?

BACKGROUND: Recent studies point toward the possible regulatory roles of two lncRNAs; metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and taurine upregulated gene 1 (TUG1) in the pathogenesis of obesity-related disorders and regulation of lipogenesis and adipogenesis. In an attempt to understand the molecules involved in human obesity pathogenesis, we aimed to evaluate the expression of MALAT1 and TUG1 in visceral adipose tissues (VAT) and subcutaneous adipose tissues (SAT) of obese women, as compared to normal-weight women. The mRNA expression of possible target genes including peroxisome proliferator-activated receptor gamma (PPARγ), PPARγ coactivator-1 alpha (PGC1α), sterol regulatory element-binding protein-1c (SREBP-1c), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) which are involved in adipogenesis and lipogenesis were also examined. METHODS: This study was conducted on 20 obese [body mass index (BMI) ≥ 30 kg/m 2] female participants and 19 normal-weight (BMI < 25 kg/m 2) female participants. Real-time PCR was performed to investigate the mRNA expression of the above-mentioned genes in VAT and SAT from all participants. RESULTS: The results showed lower mRNA levels of TUG1 in both the VAT and SAT of obese women, compared to normal-weight women. Furthermore, TUG1 expression in SAT positively correlated with BMI, waist circumference (WC), hip circumference, HOMA-IR, and insulin levels, eGFR value, creatinine levels, and hs-CRP in all participants independent of age and HOMA-IR. However, VAT mRNA expression of TUG1 had a positive correlation with obesity indices and HOMA-IR and insulin levels in the whole population. Moreover, SAT mRNA level of TUG1 was positively correlated with SAT gene expression of PGC1α, SREBP-1c, FAS, and ACC independent of age and HOMA-IR. Although mRNA expression of MALAT1 did not differ between two groups for any tissue, it was positively correlated with SAT mRNA levels of SREBP-1c, PPARγ, and their targets; FAS and ACC, as well as with VAT mRNA levels of PGC1α. CONCLUSIONS: It seems likely that TUG1 with distinct expression pattern in VAT and SAT are involved in the regulation of lipogenic and adipogenic genes and obesity-related parameters. However, more studies are necessary to establish this concept.

Adipose tissue mRNA expression of HDAC1, HDAC3 and HDAC9 in obese women in relation to obesity indices and insulin resistance.

It is well-established that an impaired adipose tissue function and morphology caused by a dysregulated gene expression contribute substantially to obesity. Nowadays, animal model studies and in vitro surveys provide evidence for possible roles of HDACs as emerging epigenetic players in the pathogenesis of obesity. However, the clinical pertinence of HDACs in the field of obesity research in humans is not yet obvious. Here, we investigated mRNA expression of HDAC1, 3 and 9 in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) of obese female participants (n = 20) and normal-weight women (n = 19). We also evaluated the association of the afore-mentioned HDACs gene expression with obesity indices, insulin resistance parameters, and other obesity-related characteristics. Our data revealed the mRNA level of HDAC1 was significantly decreased in both VAT and SAT of obese women, compared to controls. Moreover, the SAT mRNA expression of HDAC3 and VAT mRNA levels of HDAC9 were significantly lower in obese subjects than those found in controls. We observed that HDAC1 and HDAC3 expression in adipose tissue from the whole population is inversely correlated with obesity indices; BMI, waist, hip and waist-to-height ratio (WHtR). Moreover, we found that HDAC3 expression in adipose tissue had an inverse correlation with HOMA-IR, insulin levels, and serum concentration of hs-CRP. Moreover, VAT HDAC9 mRNA level is inversely correlated with obesity indices; BMI, waist, hip and WHtR and with HOMA-IR, insulin levels, and serum concentration of hs-CRP. Hence, it seems that decreased HDAC1,3 and 9 mRNA expression in adipose tissue might be associated with obesity and related abnormalities. However, more studies are needed to establish this concept.