Study of caveolin-1 gene expression in whole adipose tissue and its subfractions and during differentiation of human adipocytes

<p>Abstract</p> <p>Context</p> <p>Caveolins are 21-24 kDa integral membrane proteins that serve as scaffolds to recruit numerous signaling molecules. Specific subclasses of caveolae carry out specific functions in cell metabolism. In particular, triglycerides are synthesized at the site of fatty acid entry in one of these caveolae classes.</p> <p>Objective and Methods</p> <p>We studied the expression of caveolin-1 (<it>CAV-1</it>) gene in association with metabolic variables in 90 visceral and 55 subcutaneous adipose tissue samples from subjects with a wide range of fat mass, in the stromovascular fraction (SVC) and isolated adipocytes, and during differentiation of human adipocytes.</p> <p>Results</p> <p><it>CAV-1 </it>gene expression was significantly decreased in visceral adipose tissue (v-<it>CAV-1</it>) of obese subjects. v-<it>CAV-1 </it>was positively associated with several lipogenic genes such as acetyl-coA carboxylase (<it>ACACA</it>, r = 0.34, p = 0.004) and <it>spot-14 </it>(r = 0.33, p = 0.004). In non-obese subjects v-<it>CAV-1 </it>also correlated with fatty acid synthase (<it>FAS</it>, r = 0.60, p < 0.0001). Subcutaneous (sc) adipose tissue (s<it>c-CAV-1</it>) gene expression was not associated with these lipogenic factors when obese and non-obese subjects were studied together. In obese subjects, however, sc-<it>CAV-1 </it>was associated with fatty acid synthase (<it>FAS</it>, r = 0.36, p = 0.02), sterol regulatory element binding protein-1c (<it>SREBP-1c </it>(r = 0.58, p < 0.0001), <it>ACACA </it>(r = 0.33, p = 0.03), <it>spot-14 </it>(r = 0.36, p = 0.02), <it>PPAR-γ co-activator-1 </it>(<it>PGC-1</it>, r = 0.88, n = 19). In these obese subjects, <it>sc-CAV-1 </it>was also associated with fasting triglycerides (r = -0.50, p < 0.0001).</p> <p><it>CAV-1 </it>expression in mature adipocytes was significantly higher than in stromal vascular cells. <it>CAV-1 </it>gene expression in adipocytes from subcutaneous adipose tissue (but not in adipocytes from visceral adipose tissue) was significatively associated with fasting triglycerides. <it>CAV-1 </it>gene expression did not change significantly during differentiation of human preadipocytes from lean or obese subjects despite significant increase of FAS gene expression.</p> <p>Conclusion</p> <p>Decreased <it>CAV-1 </it>gene expression was simultaneously linked to increased triglycerides and decreased lipogenic gene expression among obese subjects, paralleling the observations of hypertriglyceridemia in <it>CAV-1 </it>knockout mice. However, the regulation of <it>CAV-1 </it>gene expression seems independent of the adipogenic program.</p

Study of caveolin-1 gene expression in whole adipose tissue and its subfractions and during differentiation of human adipocytes

Caveolins are 21-24 kDa integral membrane proteins that serve as scaffolds to recruit numerous signaling molecules. Specific subclasses of caveolae carry out specific functions in cell metabolism. In particular, triglycerides are synthesized at the site of fatty acid entry in one of these caveolae classes. OBJECTIVE AND METHODS: We studied the expression of caveolin-1 (CAV-1) gene in association with metabolic variables in 90 visceral and 55 subcutaneous adipose tissue samples from subjects with a wide range of fat mass, in the stromovascular fraction (SVC) and isolated adipocytes, and during differentiation of human adipocytes. RESULTS: CAV-1 gene expression was significantly decreased in visceral adipose tissue (v-CAV-1) of obese subjects. v-CAV-1 was positively associated with several lipogenic genes such as acetyl-coA carboxylase (ACACA, r = 0.34, p = 0.004) and spot-14 (r = 0.33, p = 0.004). In non-obese subjects v-CAV-1 also correlated with fatty acid synthase (FAS, r = 0.60, p < 0.0001). Subcutaneous (sc) adipose tissue (sc-CAV-1) gene expression was not associated with these lipogenic factors when obese and non-obese subjects were studied together. In obese subjects, however, sc-CAV-1 was associated with fatty acid synthase (FAS, r = 0.36, p = 0.02), sterol regulatory element binding protein-1c (SREBP-1c (r = 0.58, p < 0.0001), ACACA (r = 0.33, p = 0.03), spot-14 (r = 0.36, p = 0.02), PPAR-gamma co-activator-1 (PGC-1, r = 0.88, n = 19). In these obese subjects, sc-CAV-1 was also associated with fasting triglycerides (r = -0.50, p < 0.0001).CAV-1 expression in mature adipocytes was significantly higher than in stromal vascular cells. CAV-1 gene expression in adipocytes from subcutaneous adipose tissue (but not in adipocytes from visceral adipose tissue) was significatively associated with fasting triglycerides. CAV-1 gene expression did not change significantly during differentiation of human preadipocytes from lean or obese subjects despite significant increase of FAS gene expression. CONCLUSION: Decreased CAV-1 gene expression was simultaneously linked to increased triglycerides and decreased lipogenic gene expression among obese subjects, paralleling the observations of hypertriglyceridemia in CAV-1 knockout mice. However, the regulation of CAV-1 gene expression seems independent of the adipogenic program

MiRNA Expression Profile of Human Subcutaneous Adipose and during Adipocyte Differentiation

BACKGROUND: Potential regulators of adipogenesis include microRNAs (miRNAs), small non-coding RNAs that have been recently shown related to adiposity and differentially expressed in fat depots. However, to date no study is available, to our knowledge, regarding miRNAs expression profile during human adipogenesis. Thereby, the aim of this study was to investigate whether miRNA pattern in human fat cells and subcutaneous adipose tissue is associated to obesity and co-morbidities and whether miRNA expression profile in adipocytes is linked to adipogenesis. METHODOLOGY/PRINCIPAL FINDINGS: We performed a global miRNA expression microarray of 723 human and 76 viral mature miRNAs in human adipocytes during differentiation and in subcutaneous fat samples from non-obese (n = 6) and obese with (n = 9) and without (n = 13) Type-2 Diabetes Mellitus (DM-2) women. Changes in adipogenesis-related miRNAs were then validated by RT-PCR. Fifty of 799 miRNAs (6.2%) significantly differed between fat cells from lean and obese subjects. Seventy miRNAs (8.8%) were highly and significantly up or down-regulated in mature adipocytes as compared to pre-adipocytes. Otherwise, 17 of these 799 miRNAs (2.1%) were correlated with anthropometrical (BMI) and/or metabolic (fasting glucose and/or triglycerides) parameters. We identified 11 miRNAs (1.4%) significantly deregulated in subcutaneous fat from obese subjects with and without DM-2. Interestingly, most of these changes were associated with miRNAs also significantly deregulated during adipocyte differentiation. CONCLUSIONS/SIGNIFICANCE: The remarkable inverse miRNA profile revealed for human pre-adipocytes and mature adipocytes hints at a closely crosstalk between miRNAs and adipogenesis. Such candidates may represent biomarkers and therapeutic targets for obesity and obesity-related complications

Decreased TLR3 in Hyperplastic Adipose Tissue, Blood and Inflamed Adipocytes is Related to Metabolic Inflammation

Background/Aims: Obesity is characterized by the immune activation that eventually dampens insulin sensitivity and changes metabolism. This study explores the impact of different inflammatory/ anti-inflammatory paradigms on the expression of toll-like receptors (TLR) found in adipocyte cultures, adipose tissue, and blood. Methods: We evaluated by real time PCR the impact of acute surgery stress in vivo (adipose tissue) and macrophages (MCM) in vitro (adipocytes). Weight loss was chosen as an anti-inflammatory model, so TLR were analyzed in fat samples collected before and after bariatric surgery-induced weight loss. Associations with inflammatory and metabolic parameters were analyzed in non-obese and obese subjects, in parallel with gene expression measures taken in blood and isolated adipocytes/ stromal-vascular cells (SVC). Treatments with an agonist of TLR3 were conducted in human adipocyte cultures under normal conditions and upon conditions that simulated the chronic low-grade inflammatory state of obesity. Results: Surgery stress raised TLR1 and TLR8 in subcutaneous (SAT), and TLR2 in SAT and visceral (VAT) adipose tissue, while decreasing VAT TLR3 and TLR4. MCM led to increased TLR2 and diminished TLR3, TLR4, and TLR5 expressions in human adipocytes. The anti-inflammatory impact of weight loss was concomitant with decreased TLR1, TLR3, and TLR8 in SAT. Cross-sectional associations confirmed increased V/ SAT TLR1 and TLR8, and decreased TLR3 in obese patients, as compared with non-obese subjects. As expected, TLR were predominant in SVC and adipocyte precursor cells, even though expression of all of them but TLR8 (very low levels) was also found in ex vivo isolated and in vitro differentiated adipocytes. Among SVC, CD14+ macrophages showed increased TLR1, TLR2, and TLR7, but decreased TLR3 mRNA. The opposite patterns shown for TLR2 and TLR3 in V/ SAT, SVC, and inflamed adipocytes were observed in blood as well, being TLR3 more likely linked to lymphocyte instead of neutrophil counts. On the other hand, decreased TLR3 in adipocytes challenged with MCM dampened lipogenesis and the inflammatory response to Poly(I:C). Conclusion: Functional variations in the expression of TLR found in blood and hypertrophied fat depots, namely decreased TLR3 in lymphocytes and inflamed adipocytes, are linked to metabolic inflammation

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Breast cancer 1 (BrCa1) may be behind decreased lipogenesis in adipose tissue from obese subjects

The specular findings of BrCa1 and lipogenic enzymes in adipose tissue and adipocytes reported here suggest that BrCa1 might help to control fatty acid biosynthesis in adipocytes and adipose tissue from obese subject

<i>BrCa1</i> levels in human fat samples.

<p><i>Real Time-PCR:</i> Mean and 95% confidence interval for the mean of gene expression levels for <i>BrCa1</i> in subcutaneous (SC; <i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033233#pone.0033233.s001" target="_blank">Fig. 1</a>a</i>) and omental (OM; <i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033233#pone.0033233.s001" target="_blank">Fig. 1</a>c</i>) adipose tissue from non-obese (BMI<30 kg/m²) and obese (BMI≥30 kg/m²) subjects with and without T2D. <i>ELISA:</i> Mean ±2.0 SE for phosphorylated ACC normalized <i>versus</i> total ACC (ratio P-ACC/ACC) in SC (<i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033233#pone.0033233.s001" target="_blank">Fig. 1</a>b</i>; n = 33) and OM (<i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033233#pone.0033233.s002" target="_blank">Fig. 2</a>d</i>; n = 21) adipose tissue. <i>Western-blot:</i> Mean ±2.0 SE of total (BrCa1, <i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033233#pone.0033233.s002" target="_blank">Fig. 2</a>e</i>) and phosphorylated (P-BrCa1; <i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033233#pone.0033233.s002" target="_blank">Fig. 2</a>f</i>) BrCa1 protein normalized <i>versus</i> β-actin in OM fat. <b><i>†</i></b> and <b><i>*</i></b> p<0.05 for comparisons between obese with and without T2D, and the control group (non-obese and non-T2D individuals), respectively. <b><i>^#</i></b> p<0.05 for comparisons between non-obese and obese subjects.</p