Adipocyte-specific FAK deletion promotes pancreatic ß-cell apoptosis via adipose inflammatory response to exacerbate diabetes mellitus.

BACKGROUND: White adipose tissue (WAT) has a key role in maintaining energy balance throughout the body, and their dysfunction take part in the regulation of diabetes mellitus. However, the internal regulatory mechanisms underlying are still unknown. METHODS AND RESULTS: We generated adipocyte-specific FAK KO (FAK-AKO) mice and investigated their phenotype. The cascade of adipocyte, macrophage in adipocyte tissues, and pancreatic ß-cells were proposed in FAK-AKO mice and validated by cell line studies using 3T3-L1, Raw264.7 and Min6. The FAK-AKO mice exhibited glucose intolerance, reduced adipose tissue mass and increased apoptosis, lipolysis and inflammatory response in adipose tissue. We further demonstrate that adipocyte FAK deletion increases ß cell apoptosis and inflammatory infiltrates into islets, which is potentiated if mice were treated with STZ. In the STZ-induced diabetes model, FAK AKO mice exhibit less serum insulin content and pancreatic ß cell area. Moreover, serum pro-inflammatory factors increased and insulin levels decreased after glucose stimulation in FAK AKO mice. In a parallel vitro experiment, knockdown or inhibition of FAK during differentiation also increased apoptosis, lipolysis and inflammatory in 3T3-L1 adipocytes, whereas the opposite was observed upon overexpression of FAK. Moreover, coculturing LPS-treated RAW264.7 macrophages with knockdown FAK of 3T3-L1 adipocytes increased macrophage pro-inflammatory response. Furthermore, conditioned medium from above stimulated Min6 cells apoptosis (with or without STZ), whereas the opposite was observed upon overexpression of FAK. Mechanistically, FAK protein interact with TRAF6 in adipocytes and knockdown or inhibition of FAK activated TRAF6/TAK1/NF-κB signaling, which exacerbates inflammation of adipocytes themselves. CONCLUSION: Adipocyte FAK deletion promotes both adipocyte apoptosis and adipose tissue inflammation. Pro-inflammatory factors released by the FAK-null adipose tissue further trigger apoptosis in pancreatic islets induced by the administration of STZ, thereby exacerbating the diabetes mellitus. This study reveals a link between FAK-mediated adipose inflammation and diabetes mellitus, a mechanism that has not been previously recognized.

Adipose extracellular matrix deposition is an indicator of obesity and metabolic disorders.

Obesity and metabolic disorders are threats to human health. Extracellular matrix (ECM) is an important member of adipose microenvironment. ECM remodeling contributes to obesity and insulin resistance, but the roles of every single ECM component is still not fully understood. We observed glucose and lipids metabolic disorders in high-fat diet (HFD)-fed mice and humans with obesity. Higher levels of inflammatory factors and hormones existed in serum of HFD-fed mice. Multiple collagens, laminins, fibronectin, nidogen, and Hspg2 were upregulated in obese white adipose tissue (WAT) from mice and humans. These effects were stronger in subcutaneous WAT than visceral WAT in mice, but the fat depot difference was reversed in humans. The ECM structure and the morphology of adipocytes seeded on ECM were changed in the HFD group. In human visceral WAT, ECM genes showed positive correlations with blood lipids and glucose. In vitro, collagen I/IV and LAMA4 proteins showed similar changes with C/EBPα during the differentiation of adipocytes. Macromolecular crowders (MMC) promoted partial collagen and non-collagen gene expression. Oleic acid (OA) and MMC upregulated collagen I/IV and LAMA4 proteins, and the effects of MMC were stronger than that of OA. Moreover, MMC promoted the differentiation of adipocytes, but OA increased the size of lipid droplets. Positive correlations were observed between ECM genes and adipogenesis-related genes in adipocytes. In conclusion, some obesogens (such as HFD) induce ECM remodeling, and the upregulation of ECM components is closely related to adipogenesis, suggesting that adipose ECM deposition is an indicator of obesity and metabolic disorders.

Saponins from Panax japonicus alleviate adipose tissue fibrosis and metabolic dysfunction in high-fat-diet-induced obese mice.

INTRODUCTION: Adipose tissue fibrosis is a typical feature of adipose tissue dysfunction in obese individuals, which is closely related to metabolic diseases. OBJECTIVE: To explore the effect and mechanism of Saponins from Panax japonicus (SPJ) on adipose tissue fibrosis in obese mice induced by high fat diet (HFD). MATERIALS AND METHODS: We established a HFD induced obese mice model. Then the obese mice were treated with 90 mg/kg SPJ by oral gavage for 10 weeks. The levels of adipose tissue fibrosis and molecules related to signalling pathways were measured. Then the effects of SPJ on TGFß1-induced fibrosis in 3T3-L1 differentiated adipocytes were evaluated. RESULTS: SPJ reduced body weight, fat accumulation, and improved glucose and lipid metabolism in obese mice. SPJ decreased collagen deposition and expressions of fibrotic genes in epididymal white adipose tissue (eWAT) of obese mice. SPJ decreased the levels of TGFß1 protein and pSmad2, and increased the expression of PPARγ and PGC1α, thus alleviating oxidative stress in eWAT. Consistently, SPJ inhibited TGFß1-induced fibrosis in 3T3-L1 differentiated adipocytes. CONCLUSIONS: SPJ may alleviate adipose tissue fibrosis and improve obesity by inhibiting TGFß1/Smad2 and activating PPARγ/PGC1α pathway. SPJ is expected to become an efficient medicine for treatment of obesity.

High-Fat-Diet-Induced Extracellular Matrix Deposition Regulates Integrin-FAK Signals in Adipose Tissue to Promote Obesity.

SCOPE: High-fat-diet (HFD) is an important factor in obesity. Extracellular matrix (ECM) regulates white adipose tissue (WAT), but its mechanism is unknown. METHODS AND RESULTS: This study uses three models-HFD-fed mice, human with obesity, and 3T3-L1 adipocytes with oleic acid (OA)/macromolecular crowders (MMC) treatment. Glucose and lipids metabolic disorders, increased collagen I/IV and laminin α2/4 (LAMA2/4), and upregulated integrins (ITGA1/ITGA7) - focal adhesion kinase (FAK) - c-Jun N-terminal kinase (JNK)/extracellular regulated protein kinase 1/2 (ERK1/2) signals in obese WAT from mice and human are observed. The upregulation of ECM - integrin - FAK signals is stronger in subcutaneous WAT than that in visceral WAT of mice, but these results are reversed in human. In vitro, oleic acid (OA) promotes lipid accumulation and upregulates collagen IV, LAMA4, and p-JNK. MMC is used to induce ECM deposition in adipocytes. MMC promotes adipocyte differentiation and integrins - FAK - JNK/ERK1/2 signals. When FAK phosphorylation is inhibited, downstream p-JNK is decreased. Inhibition of FAK phosphorylation reduces adipocyte differentiation, but MMC partially reverses this effect. CONCLUSION: HFD-induced ECM deposition, whose signals are transmitted into adipocytes through upregulating ITGA1/ITGA7, activates the phosphorylation of intracellular FAK - JNK/ERK1/2 signals, and promotes adipogenesis in WAT. This mechanism provides novel therapeutic targets to treat obesity.

Maternal nicotine exposure impairs brown adipose tissue via AMPK-SIRT1-PGC-1α signals in male offspring.

AIMS: Maternal nicotine exposure during pregnancy and lactation is associated with obesity in offspring. Brown adipose tissue (BAT) is correlated with energy metabolism and obesity. In this study, we explored the mechanism of maternal nicotine exposure on BAT changes in male offspring. MAIN METHODS: Pregnant rats were randomly assigned to nicotine (1.0 mg/kg twice per day, subcutaneous administration) or control groups. In vitro, C3H10T1/2 cells were induced to differentiate into mature brown adipocytes, and 0-50 µM nicotine was given to C3H10T1/2 cells during the differentiation process. KEY FINDINGS: Nicotine-exposed males had white-like adipocytes and abnormal mitochondria structure in iBAT at 26 weeks. The expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway were downregulated in the nicotine group at 26 weeks rather than 4 weeks. In vitro, 50 µM nicotine decreased the expression of mitochondrial genes, UCP1 and AMPK-SIRT1-PGC-1α pathway in brown adipocytes. SIGNIFICANCE: Maternal nicotine exposure showed the "programming" effect on the decreased brown-like phenotype in BAT of adult male offspring via downregulating AMPK-SIRT1-PGC-1α pathway. This impairment of BAT may be a potential mechanism of nicotine-induced obesity in male offspring.

Maternal nicotine exposure during pregnancy and lactation induces brown adipose tissue whitening in female offspring.

Maternal nicotine exposure during pregnancy and lactation is associated with obesity in female offspring. Brown adipose tissue (BAT) is related to energy metabolism and obesity. In this study, we explored the mechanism of maternal nicotine exposure on BAT "whitening" in female offspring. Pregnant rats were randomly assigned to nicotine (1.0 mg/kg twice per day, subcutaneous administration) or control groups. The weight, structure, and microvascular density of interscapular BAT (iBAT) and the expression of PGC-1αUCP1 signals, mitochondrial biogenesis-related genes and angiogenesis-related genes were tested in 4- and 26-week-aged female offspring. In vitro, C3H10T1/2 cells were induced to differentiate into mature brown adipocytes, and 0-50 µM nicotine was treated on cells during the differentiation process. Nicotine-exposed females had higher iBAT weight, white-like adipocytes and abnormal mitochondrial structure in iBAT at 26 weeks rather than 4 weeks. The PGC-1αUCP1 signals and brown-like genes were down-regulated at 26 weeks, but the microvascular density and the expression of pro-angiogenic factors reduced more at 4 weeks in the nicotine group. In vitro, 50 µM nicotine significantly decreased the expression of PGC-1αUCP1 signals and angiogenesis-related genes. In conclusion, maternal nicotine exposure during pregnancy and lactation led to the "whitening" of BAT in adult female offspring: nicotine decreased BAT angiogenesis in the early development stage, and then, the impairment of blood vessels programed for the reduction of BAT phenotype through down-regulating the PGC-1αUCP1 signals in adulthood. This impairment of BAT may be a potential mechanism of nicotine-induced obesity in female offspring.

Maternal nicotine exposure enhances adipose tissue angiogenic activity in offspring: Sex and age differences.

Maternal nicotine exposure during pregnancy and lactation (NIC) is associated with dysfunction of white adipose tissue (WAT). We focused on the NIC-induced WAT angiogenesis and explored its sex and age differences. Pregnant rats were randomly assigned to NIC (1.0 mg/kg nicotine twice per day) or control groups. Distribution and density of blood vessels were observed. Angiogenesis-related genes were tested at 4, 12 and 26 weeks to estimate angiogenic activity. In vitro, nicotine concentration- and time-response experiments (0-50 µM) were conducted in 3T3-L1. Lipid accumulation and angiogenesis-related genes were tested. NIC increased the blood vessels in inguinal subcutaneous WAT (igSWAT) and gonadal WAT (gWAT) of 26-week-aged male and 4-week-aged female offspring. In males, nicotine showed higher angiogenic activity at 26 weeks than at 4 weeks in igSWAT and gWAT. In females, nicotine's angiogenic activity was higher at 4 weeks than 26 weeks in igSWAT and gWAT. In vitro, nicotine promoted adipocyte differentiation, and increased the expression of angiogenesis-related genes in concentration- and time dependent manners. In conclusion, NIC-induced enhancement of angiogenic activity in WAT presented sex and age differences: nicotine showed higher angiogenic activity in adulthood than in childhood of male offspring, but the converse results were observed in female offspring.

The association between maternal nicotine exposure and adipose angiogenesis in female rat offspring: A mechanism of adipose tissue function changes.

Maternal smoking during pregnancy and lactation is associated with increased fat mass in the offspring, but the mechanism by which this occurs is not fully understood. Our study focused on the relationships among maternal nicotine exposure, adipose angiogenesis and adipose tissue function in female offspring. Pregnant rats were randomly assigned to nicotine or control groups. Microvascular density, lipid metabolism and α7nAChR-Egr1-FGF2 signaling pathway genes/proteins were tested in 4-, 12- and 26-week female offspring. In vitro, nicotine concentration- and time-response experiments were conducted in 3T3-L1. Lipid metabolism and α7nAChR-Egr1-FGF2 signaling pathway genes/proteins were tested. The conditioned media of differentiated 3T3-L1 treated with nicotine were used to observe tube formation in human umbilical vein endothelial cells (HUVECs). Nicotine-exposed females presented higher adipose microvascular density. The gene expression of α7nAChR, Egr1 and FGF2 was significantly increased in gonadal white adipose tissue (gWAT) and inguinal subcutaneous WAT (igSWAT) of nicotine-exposed females at 4 weeks of age. The protein expression of α7nAChR, Egr1 and FGF2 was increased in gWAT and igSWAT of nicotine-exposed females at 4 weeks of age, and increased in gWAT at 26 weeks. In vitro, nicotine increased the expression of lipid metabolism and α7nAChR-Egr1-FGF2 signaling pathway genes/proteins in a concentration- and time-dependent manner. In the tube formation experiment, adipocytes affected by nicotine promoted HUVEC angiogenesis. Therefore, maternal nicotine exposure promoted the early angiogenesis of adipose tissue via the α7nAChR-Egr1-FGF2 signaling pathway, and this angiogenesis mechanism was associated with increased adipogenesis in adipose tissue of female offspring.

Age Differences in the Relationship between Secondhand Smoke Exposure and Risk of Metabolic Syndrome: A Meta-Analysis.

Secondhand smoke (SHS), a common environmental exposure factor, has become a serious public health problem. Metabolic syndrome is another worldwide clinical challenge. Our study tried to determine the age differences in the relationship between SHS and the risk of metabolic syndrome. Studies were searched in PubMed and Web of Science from 11 November to 30 November 2018. Eighteen studies were finally included based on inclusion and exclusion criteria. The relationship between SHS and the risk indicators of metabolic syndrome was analyzed. The weighted mean difference (WMD) of fasting plasma glucose (FPG), insulin, body mass index (BMI), and waist circumference (WC), and the standard mean difference (SMD) of total cholesterol, triglycerides, and low- and high-density lipoprotein-cholesterol (LDL-C, HDL-C) were calculated in a meta-analysis. SHS was positively associated with the level of insulin and WC. According to the subgroup analysis based on age difference, SHS was positively associated with FPG in the upper age group, and positively associated with LDL-C and negatively associated with HDL-C in the lower age group. BMI showed a more obvious positive correlation in the adults group than in the children and the teenagers group. In conclusion, the association of metabolic syndrome with SHS varies with age. When exposed to SHS, older people may be more susceptible to glucose metabolic disorder, but younger people may be more susceptible to lipid metabolic disorder.

Effects of maternal omega-3 fatty acids supplementation during pregnancy/lactation on body composition of the offspring: A systematic review and meta-analysis.

BACKGROUND & AIMS: The effect of maternal omega-3 fatty acids intake on the body composition of the offspring is unclear. The aim of this study was to conduct a systematic review and meta-analysis to confirm the effects of omega-3 fatty acids supplementation during pregnancy and/or lactation on body weight, body length, body mass index (BMI), waist circumference, fat mass and sum of skinfold thicknesses of offspring. METHODS: Human intervention studies were selected by a systematic search of PubMed, Web of Science, the Cochrane Library and references of related reviews and studies. Randomized controlled trials of maternal omega-3 fatty acids intake during pregnancy or lactation for offspring's growth were included. The data were analyzed with RevMan 5.3 and Stata 12.0. Effect sizes were presented as weighted mean differences (WMD) or standardized mean difference (SMD) with 95% confidence intervals (95% CI). RESULTS: Twenty-six studies comprising 10,970 participants were included. Significant increases were found in birth weight (WMD = 42.55 g, 95% CI: 21.25, 63.85) and waist circumference (WMD = 0.35 cm, 95% CI: 0.04, 0.67) in the omega-3 fatty acids group. There were no effects on birth length (WMD = 0.09 cm, 95% CI: -0.03, 0.21), postnatal length (WMD = 0.13 cm, 95% CI: -0.11, 0.36), postnatal weight (WMD = 0.04 kg, 95% CI: -0.07, 0.14), BMI (WMD = 0.09, 95% CI: -0.05, 0.23), the sum of skinfold thicknesses (WMD = 0.45 mm, 95% CI: -0.30, 1.20), fat mass (WMD = 0.05 kg, 95% CI: -0.01, 0.11) and the percentage of body fat (WMD = 0.04%, 95% CI: -0.38, 0.46). CONCLUSIONS: This meta-analysis showed that maternal omega-3 fatty acids supplementation can increase offspring's birth weight and postnatal waist circumference. However, it did not appear to influence children's birth length, postnatal weight/length, BMI, sum of skinfold thicknesses, fat mass and the percentage of body fat during postnatal period. Larger, well-designed studies are recommended to confirm this conclusion.

Perinatal nicotine exposure increases obesity susceptibility by peripheral leptin resistance in adult female rat offspring.

Maternal nicotine (NIC) exposure causes overweight, hyperleptinemia and metabolic disorders in adult offspring. Our study aims to explore the underlying mechanism of perinatal NIC exposure increases obesity susceptibility in adult female rat offspring. In our model, we found that adult NIC-exposed females presented higher body weight and subcutaneous and visceral fat mass, as well as larger adipocytes, while no change was found in food intake. Serum profile showed a higher serum glucose, insulin and leptin levels in NIC-exposed females. In adipose tissue and liver, the leptin signaling pathway was blocked at 26 weeks, presented lower Janus tyrosine kinase 2 and signal transducer and activator of transcription 3 gene expression, higher suppressor of cytokine signaling 3 gene expression (in adipose tissue) and lower leptin receptors gene expression (in liver), indicating that peripheral leptin resistance occurred in NIC-exposed adult females. In female rats, the expression of lipolysis genes was affected dominantly in adipose tissue, but lipogenesis genes was affected in liver. Furthermore, the glucose and insulin tolerance tests showed a delayed glucose clearance and a higher area under the curve in NIC-exposed females. Therefore, perinatal NIC exposure programed female rats for adipocyte hypertrophy and obesity in adult life, through the leptin resistance in peripheral tissue.

Intrauterine growth retardation-associated syncytin b hypermethylation in maternal rat blood revealed by DNA methylation array analysis.

BackgroundEmerging evidence suggests that DNA methylation in maternal blood is a promising target for intrauterine growth retardation (IUGR) screening, a common developmental toxicity. Here, we aimed to screen out IUGR-related DNA methylation status in maternal blood via high-throughput profiling.MethodsPregnant Wistar rats were subcutaneously administered nicotine (1 mg/kg) twice per day from gestational day (GD) 11 to GD20 to establish the IUGR model. MeDIP array assays and the following GO analysis were used to evaluate DNA methylation status in maternal blood. One placental development-associated gene was selected for further confirmation.ResultsGenes regulating the development of multiple organs and major body systems had changed DNA methylation frequencies in the maternal blood of IUGR rats. Placental development, which can affect the development of multiple fetal organs and induce IUGR, is a hypermethylated cluster consisting of four significantly changed genes, including syncytin b (Synb), Lrrc15, Met, and Tex19.1. With the most significant change, Synb hypermethylation in maternal blood was confirmed by bisulfite-sequencing PCR (BSP). Moreover, decreased Synb expression and histological changes were observed in IUGR placentae.ConclusionThe IUGR-associated DNA methylation profile in maternal blood, such as placenta-related Synb hypermethylation, provides evidence for further studies on possible IUGR biomarkers.

Prenatal caffeine exposure induced high susceptibility to metabolic syndrome in adult female offspring rats and its underlying mechanisms.

Our previous studies have demonstrated that prenatal caffeine exposure (PCE) induced an intrauterine programming of hypothalamic-pituitary-adrenal axis (HPAA)-associated neuroendocrine metabolism in 3-month-old offspring rats. In this study, we aimed to confirm this programming disorder and high susceptibility to metabolic syndrome (MS) in 10-month-old female PCE offspring with postnatal catch-up growth. We found that PCE female offspring rats showed decreased bodyweight but a higher rate of weight gain after birth. Moreover, in the offspring, basal hyperinsulinemia and insulin resistance were observed before unpredictable chronic stress (UCS), but serum total cholesterol (TCH) levels and triglyceride/high-density lipoprotein-cholesterol (TG/HDL-C), TCH/HDL-C and low-density lipoprotein-cholesterol/HDL-C (LDL-C/HDL-C) ratio changes were increased after UCS, accompanied by morphological damage of the related tissues. These results suggested that PCE adult female offspring rats were highly susceptible to MS, which is related to HPAA-associated neuroendocrine-metabolic programming disorder.

Increased Fetal Thymocytes Apoptosis Contributes to Prenatal Nicotine Exposure-induced Th1/Th2 Imbalance in Male Offspring Mice.

Nicotine, a definite risk factor during pregnancy, is an immunomodulator. This study was designed to investigate the effects of prenatal nicotine exposure (PNE) on the balance of Th1/Th2 in offspring, and further explore the developmental origin mechanisms from the perspective of fetal thymocytes apoptosis. Pregnant Balb/c mice were administered 1.5 mg/kg nicotine subcutaneously twice per day from gestational day (GD) 9 to GD18. Results showed that PNE could cause a Th2 shift in male offspring, manifested as increased ratio of IgG1/IgG2a, IL-4 production in serum, and IL-4/IFN-γ expression ratio in spleen. Increased apoptosis of total thymocytes and CD4SP and reduced cell proportion of CD4SP were found in PNE male offspring on postnatal day (PND) 14 and PND 49. In the fetuses, decreased body weight and organ index of fetal thymus, histological changes in fetal thymus, reduced CD4SP proportion and increased fetal thymocyte apoptosis were observed in nicotine group. The increased mRNA expression of genes involved in Fas-mediated apoptotic pathway and protein expression of Fas were also detected. In conclusion, PNE could cause a Th2 shift in male offspring mediated by reduced CD4+ T cells output, which may result from the increasing apoptosis of total thymocytes and CD4SP.

Nicotine Suppressed Fetal Adrenal StAR Expression via YY1 Mediated-Histone Deacetylation Modification Mechanism.

Steroidogenic acute regulatory (StAR) protein plays a pivotal role in steroidogenesis. Previously, we have demonstrated that prenatal nicotine exposure suppressed fetal adrenal steroidogenesis via steroidogenic factor 1 deacetylation. This study further explored the potential role of the transcriptional repressor Yin Yang 1 (YY1) in nicotine-mediated StAR inhibition. Nicotine was subcutaneously administered (1.0 mg/kg) to pregnant rats twice per day and NCI-H295A cells were treated with nicotine. StAR and YY1 expression were analyzed by real-time PCR, immunohistochemistry, and Western blotting. Histone modifications and the interactions between the YY1 and StAR promoter were assessed using chromatin immunoprecipitation (ChIP). Prenatal nicotine exposure increased YY1 expression and suppressed StAR expression. ChIP assay showed that there was a decreasing trend for histone acetylation at the StAR promoter in fetal adrenal glands, whereas H3 acetyl-K14 at the YY1 promoter presented an increasing trend following nicotine exposure. Furthermore, in nicotine-treated NCI-H295A cells, nicotine enhanced YY1 expression and inhibited StAR expression. ChIP assay showed that histone acetylation decreased at the StAR promoter in NCI-H295A cells and that the interaction between the YY1 and StAR promoter increased. These data indicated that YY1-medicated histone deacetylation modification in StAR promoters might play an important role in the inhibitory effect of nicotine on StAR expression.

Prenatal and lactation nicotine exposure affects morphology and function of brown adipose tissue in male rat offspring.

The aim of this study was to investigate the effects of prenatal and lactation nicotine exposure on the morphology and function of brown adipose tissue (BAT) in male rat offspring. We conducted a morphological assay and gene expression study of interscapular BAT (iBAT) in male rat offspring. The male offspring from nicotine-exposed dams exhibited higher body weight and iBAT weight. Hematoxylin and eosin staining and transmission electron microscopy showed that iBAT from nicotine-exposed male offspring presented a "whitening" phenotype characterized by lipid droplet accumulation and impaired mitochondria with a randomly oriented and fractured cristae. The expression of the iBAT structure and function-related genes all decreased in nicotine-exposed male offspring. These data indicate that prenatal and lactation nicotine exposure affects morphology and function of iBAT in male rat offspring.

Perinatal Nicotine Exposure Increases Obesity Susceptibility in Adult Male Rat Offspring by Altering Early Adipogenesis.

The present study aims to evaluate whether perinatal nicotine (NIC) exposure increases obesity susceptibility in adult male rat offspring by altering early adipogenesis. NIC was sc administered (2.0 mg/kg per day) to pregnant rats from gestational day 9 to the time of weaning (postnatal day 28). At weaning, NIC-exposed male pups had an increased body weight and inguinal sc fat mass and a decreased average cell area of adipocyte, which was accompanied by an overexpression of adipogenic and lipogenic genes in the epididymal white adipose tissue. Additionally, the hepatic lipogenic gene levels from NIC-exposed male pups were also affected. At 12 and 26 weeks of age, body weight and fat mass were increased, whereas there was no change in food intake in NIC-exposed male offspring. Adipogenic and lipogenic genes, glucose transporter 4, and leptin mRNA levels were increased, whereas adiponectin mRNA levels were decreased in the epididymal white adipose tissue of NIC-exposed males. The hepatic lipogenic gene expression of NIC-exposed males was increased. NIC-exposed male offspring showed normal glycemia and a higher serum insulin level, homeostasis model assessment of insulin resistance, and homeostasis model assessment of ß-cell function. Furthermore, the NIC-exposed male offspring showed higher serum lipids and Castelli index I and lower nonesterified fatty acid. At 26 weeks, in the ip glucose and insulin tolerance tests, the glucose clearance was delayed, and the area under the curve was higher in the NIC-exposed male offspring. In conclusion, perinatal NIC exposure increased obesity susceptibility in adult male rat offspring by altering early adipogenesis.

Selection of Suitable Reference Genes for Quantitative Real-Time PCR Normalization in Three Types of Rat Adipose Tissue.

Quantitative real-time PCR (qRT-PCR) is the most classical technique in the field of gene expression study. This method requires an appropriate reference gene to normalize mRNA levels. In this study, the expression stability of four frequently-used reference genes in epididymal white adipose tissue (eWAT), inguinal beige adipose tissue (iBeAT) and brown adipose tissue (BAT) from obese and lean rats were evaluated by geNorm, NormFinder and BestKeeper. Based on the Minimum Information for Publication of Quantitative Real-Time PCR Experiments (MIQE) guidelines, the two most stable reference genes were recommended in each type of adipose tissue. Two target genes were applied to test the stability of the reference genes. The geNorm and NormFinder results revealed that GAPDH and 36B4 exhibited the highest expression stabilities in eWAT, while 36B4 and ß-actin had the highest expression stabilities in iBeAT and BAT. According to the results of the BestKeeper analysis, 36B4 was the most stable gene in eWAT, iBeAT and BAT, in terms of the coefficient of variance. In terms of the coefficient of correlation, GAPDH, 36B4 and ß-actin were the most stable genes in eWAT, iBeAT and BAT, respectively. Additionally, expected results and statistical significance were obtained using a combination of two suitable reference genes for data normalization. In conclusion, 36B4 and GAPDH, in combination, are the best reference genes for eWAT, while 36B4 and ß-actin are two most suitable reference genes for both iBeAT and BAT. We recommend using these reference genes accordingly.

Effects of prenatal and lactation nicotine exposure on glucose homeostasis, lipogenesis and lipid metabolic profiles in mothers and offspring.

There is increasing evidence suggesting that maternal nicotine (NIC) exposure alone can lead to many deleterious consequences in the fetus. In this study, we aimed to evaluate the effects of prenatal and lactation NIC exposure on glucose homeostasis, lipogenesis and lipid metabolism in mothers and pups. After maternal NIC exposure (from gestational day 9 to weaning), NIC mothers showed lower body weight, decreased parametrial white adipose tissue (pWAT) and inguinal WAT weights, lower homeostasis model assessment of beta cell function, higher serum total cholesterol (TC) and low-density lipoprotein cholesterol levels, higher Castelli index values, lower hepatic mRNA levels of sterol regulatory element binding protein-1c (SREBP1c), lipoprotein lipase, acetyl-CoA carboxylase, fatty acid synthase (FAS) and glucose transporters 4 (GLUT4), as well as lower SREBP1c, FAS, leptin and GLUT4 mRNA levels in pWAT. However, female NIC pups presented higher body weights and serum TC levels, and increased trends for high density lipoprotein-cholesterol and Castelli index I. Male NIC pups had higher body weight, serum TC levels and Castelli index I values, and lower glycemia levels. Additionally, hepatic and adipose FAS gene expression from the female NIC pups presented a decreasing trend, while the male NIC pups had lower hepatic FAS expression and higher adipose FAS expression. In conclusion, prenatal and lactation NIC exposure induced deleterious effects on the glucose homeostasis, lipogenesis and lipid metabolism in both mothers and pups, which may promote several important metabolic disorders in the progeny. Additionally, there are gender-specific effects on pups.

Maternal and fetal metabonomic alterations in prenatal nicotine exposure-induced rat intrauterine growth retardation.

Prenatal nicotine exposure causes adverse birth outcome. However, the corresponding metabonomic alterations and underlying mechanisms of nicotine-induced developmental toxicity remain unclear. The aims of this study were to characterize the metabolic alterations in biofluids in nicotine-induced intrauterine growth retardation (IUGR) rat model. In the present study, pregnant Wistar rats were intragastrically administered with different doses of nicotine (0.5, 1.0 and 2.0 mg/kg d) from gestational day (GD) 11-20. The metabolic profiles of the biofluids, including maternal plasma, fetal plasma and amniotic fluid, were analyzed using (1)H nuclear magnetic resonance (NMR)-based metabonomic techniques. Prenatal nicotine exposure caused noticeably lower body weights, higher IUGR rates of fetal rats, and elevated maternal and fetal corticosterone (CORT) levels compared to the controls. The correlation analysis among maternal, fetal serum CORT levels and fetal bodyweight suggested that the levels of maternal and fetal serum CORT presented a positive correlation (r=0.356, n=32, P<0.05), while there was a negative correlation between fetal (r=-0.639, n=32, P<0.01) and maternal (r=-0.530, n=32, P<0.01) serum CORT level and fetal bodyweight. The fetal metabonome alterations included the stimulation of lipogenesis and the decreased levels of glucose and amino acids. The maternal metabonome alterations involved the enhanced blood glucose levels, fatty acid oxygenolysis, proteolysis and amino acid accumulation. These results suggested that prenatal nicotine exposure is associated with an altered maternal and fetal metabonome, which may be related to maternal increased glucocorticoid level induced by nicotine.