MiRNA expression profile of human subcutaneous adipose and during adipocyte differentiation

This is an open-access article distributed under the terms of the Creative Commons Attribution License.-- et al.[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.This work was supported by research grants from the Ministerio de Educación y Ciencia (MEC) (SAF2008-02073), the Instituto de Salud Carlos III (CIBERObN, CB06/03/0010), and the Hospital Dr. Josep Trueta de Girona.Peer reviewe

Decreased STAMP2 expression in association with visceral adipose tissue dysfunction

10 páginas, 6 figuras, 2 tablas.-- et al.[Context]: Six-transmembrane protein of prostate 2 (STAMP2) is a counter-regulator of inflammation and insulin resistance according to findings in mice. However, there have been contradictory reports in humans. [Objective]: We aimed to explore STAMP2 in association with inflammatory and metabolic status of human obesity. [Design, Patients, and Methods]: STAMP2 gene expression was analyzed in adipose tissue samples (171 visceral and 67 sc depots) and during human preadipocyte differentiation. Human adipocytes were treated with macrophage-conditioned medium, TNF-α, and rosiglitazone. [Results]: In visceral adipose tissue, STAMP2 gene expression was significantly decreased in obese subjects, mainly in obese subjects with type 2 diabetes. STAMP2 gene expression and protein were significantly and inversely associated with obesity phenotype measures (body mass index, waist, hip, and fat mass) and obesity-associated metabolic disturbances (systolic blood pressure and fasting glucose). In addition, STAMP2 gene expression was positively associated with lipogenic (FASN, ACC1, SREBP1, THRSP14, TRα, and TRα1), CAV1, IRS1, GLUT4, and CD206 gene expression. In sc adipose tissue, STAMP2 gene expression was not associated with metabolic parameters. In both fat depots, STAMP2 gene expression in stromovascular cells was significantly higher than in mature adipocytes. STAMP2 gene expression was significantly increased during the differentiation process in parallel to adipogenic genes, being increased in preadipocytes derived from lean subjects. Macrophage-conditioned medium (25%) and TNF-α (100 ng/ml) administration increased whereas rosiglitazone (2 μM) decreased significantly STAMP2 gene expression in human differentiated adipocytes. [Conclusions]: Decreased STAMP2 expression (mRNA and protein) might reflect visceral adipose dysfunction in subjects with obesity and type 2 diabetes.Peer reviewe

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

The MRC1/CD68 ratio is positively associated with adipose tissue lipogenesis and with muscle mitochondrial gene expression in humans

This is an open-access article distributed under the terms of the Creative Commons Attribution License.[Background]: Alternative macrophages (M2) express the cluster differentiation (CD) 206 (MCR1) at high levels. Decreased M2 in adipose tissue is known to be associated with obesity and inflammation-related metabolic disturbances. Here we aimed to investigate MCR1 relative to CD68 (total macrophages) gene expression in association with adipogenic and mitochondrial genes, which were measured in human visceral [VWAT, n = 147] and subcutaneous adipose tissue [SWAT, n = 76] and in rectus abdominis muscle (n = 23). The effects of surgery-induced weight loss were also longitudinally evaluated (n = ).[Results]: MCR1 and CD68 gene expression levels were similar in VWAT and SWAT. A higher proportion of CD206 relative to total CD68 was present in subjects with less body fat and lower fasting glucose concentrations. The ratio MCR1/CD68was positively associated with IRS1gene expression and with the expression of lipogenic genes such as ACACA, FASN and THRSP, even after adjusting for BMI. The ratio MCR1/CD68 in SWAT increased significantly after the surgery-induced weight loss (+44.7%; p = 0.005) in parallel to the expression of adipogenic genes. In addition, SWAT MCR1/CD68ratio was significantly associated with muscle mitochondrial gene expression (PPARGC1A, TFAM and MT-CO3). AT CD206 was confirmed by immunohistochemistry to be specific of macrophages, especially abundant in crown-like structures. [Conclusion]: A decreased ratio MCR1/CD68 is linked to adipose tissue and muscle mitochondrial dysfunction at least at the level of expression of adipogenic and mitochondrial genes. © 2013 moreno-navarrete et al.This work was supported by grant SAF-2009-10461 and grant PI11-00214 from the Ministerio de Economía y Competitividad, Spain.Peer Reviewe

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

Genome-wide DNA methylation pattern in visceral adipose tissue differentiates insulin-resistant from insulin-sensitive obese subject

Elucidating the potential mechanisms involved in the detrimental effect of excess body weight on insulin action is an important priority in counteracting obesity-associated diseases. The present study aimed to disentangle the epigenetic basis of insulin resistance by performing a genome-wide epigenetic analysis in visceral adipose tissue (VAT) from morbidly obese patients depending on the insulin sensitivity evaluated by the clamp technique. The global human methylome screening performed in VAT from 7 insulin-resistant (IR) and 5 insulin-sensitive (IS) morbidly obese patients (discovery cohort) analyzed using the Infinium HumanMethylation450 BeadChip array identified 982 CpG sites able to perfectly separate the IR and IS samples. The identified sites represented 538 unique genes, 10% of which were diabetes-associated genes. The current work identified novel IR-related genes epigenetically regulated in VAT, such as COL9A1, COL11A2, CD44, MUC4, ADAM2, IGF2BP1, GATA4, TET1, ZNF714, ADCY9, TBX5, and HDACM. The gene with the largest methylation fold-change and mapped by 5 differentially methylated CpG sites located in island/shore and promoter region was ZNF714. This gene presented lower methylation levels in IR than in IS patients in association with increased transcription levels, as further reflected in a validation cohort (n = 24; 11 IR and 13 IS). This study reveals, for the first time, a potential epigenetic regulation involved in the dysregulation of VAT that could predispose patients to insulin resistance and future type 2 diabetes in morbid obesity, providing a potential therapeutic target and biomarkers for counteracting this process

EXPLORING THE IMPACT OF APOE POLYMORPHISM ON THE MOLECULAR, MORPHOLOGICAL AND FUNCTIONAL PROFILE OF iPSC-DERIVED ASTROCYTES FROM ALZHEIMER'S PATIENTS

Comunicación presentada a FENS Forum 2022Alzheimer¿s disease (AD) is pathologically characterised by the presence of amyloid-beta plaques, neurofibrillary tangles containing hyperphosphorylated Tau protein, neuroinflammation and neuronal death leading to progressive cognitive impairment. The ¿4 allele of the gene encoding apolipoprotein E (APOE), which is mainly expressed in glial cells, is the strongest genetic risk factor for sporadic AD. Increasing evidence has shown that APOE4 may disrupt normal astrocyte activity, potentially contributing to AD pathology, but the impact of different APOE alleles on astrocyte differentiation, maturation and function is not yet fully understood. To go in depth on these questions, we obtained induced pluripotent stem cells (iPSCs) from fibroblasts of AD patients carrying ¿3 and ¿4 alleles (in homozygosis) and from healthy patients. We also used gene-edited iPSC lines homozygous for the main APOE variants and an APOE knock-out line. iPSC-derived human astrocytes were generated by establishing a differentiation protocol through the consecutive addition of small molecules and growth factors, and the expression of typical markers (GFAP, GLT1, AQP4 and S100beta) and APOE was analysed. In addition, astrocytes exhibited functional features like glutamate uptake capacity and calcium waves production. They also responded to an inflammatory stimulus (IL-1beta and TNF-alpha) or to the presence of amyloid-beta 1-42 peptide by changing their morphology and increasing the expression levels of pro-inflammatory factors and cytokines. Our results shed light on the potential dual role of APOE polymorphism and the individual¿s genetic background in favouring or perhaps preventing AD pathology

ANALYSING THE MOLECULAR, MORPHOLOGICAL AND FUNCTIONAL PROFILE OF iPSC-DERIVED ASTROCYTES FROM ALZHEIMER'S DISEASE PATIENTS

Comunicación presentada en Global Summit on Neurodegenerative Diseases NEURO 2020/22The ε4 allele of the gene encoding apolipoprotein E (APOE), which is mainly expressed in glial cells, is the strongest genetic risk factor for sporadic AD. Increasing evidence has shown that APOE4 may disrupt normal astrocyte activity, potentially contributing to AD pathology, but the impact of different APOE alleles on astrocyte maturation and function as well as their inflammatory profile is not yet fully understood. To answer these questions, we obtained induced pluripotent stem cells (iPSCs) from fibroblasts of AD patients carrying ε3 and ε4 alleles (in homozygosis) and from healthy patients. We also used gene-edited iPSC lines homozygous for the main APOE variants and an APOE knock-out line. iPSC-derived human astrocytes were generated through the consecutive addition of small molecules and growth factors to the culture medium, and the expression of typical markers (GFAP, GLT1, AQP4 and S100beta) was analysed. In addition, astrocytes exhibited functional features like glutamate uptake capacity and calcium waves. They also responded to an inflammatory stimulus (IL-1beta and TNF-alpha) or to the presence of amyloid-beta 1-42 peptide by changing their morphology and increasing the expression levels of pro-inflammatory factors and cytokines. Our results shed light on the potential dual role of APOE polymorphism and the individual's genetic background in favouring or perhaps preventing AD pathology

Adipose tissue knockdown of lysozyme reduces local inflammation and improves adipogenesis in high-fat diet-fed mice

Chronic systemic low-level inflammation in metabolic disease is known to affect adipose tissue biology. Lysozyme (LYZ) is a major innate immune protein but its role in adipose tissue has not been investigated. Here, we aimed to investigate LYZ in human and rodents fat depots, and its possible role in obesity-associated adipose tissue dysfunction. LYZ mRNA and protein were identified to be highly expressed in adipose tissue from subjects with obesity and linked to systemic chronic-low grade inflammation, adipose tissue inflammation and metabolic disturbances, including hyperglycemia, dyslipidemia and decreased markers of adipose tissue adipogenesis. These findings were confirmed in experimental models after a high-fat diet in mice and rats and also in ob/ob mice. Importantly, specific inguinal and perigonadal white adipose tissue lysozyme (Lyz2) gene knockdown in high-fat diet-fed mice resulted in improved adipose tissue inflammation in parallel to reduced lysozyme activity. Of note, Lyz2 gene knockdown restored adipogenesis and reduced weight gain in this model. In conclusion, altogether these observations point to lysozyme as a new actor in obesity-associated adipose tissue dysfunction. The therapeutic targeting of lysozyme production might contribute to improve adipose tissue metabolic homeostasis

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