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MicroRNAs (miRNAs) are promising drug targets for obesity and metabolic disorders. Recently, miRNA mimics are providing a unique mechanism of action that guides the process for drug development and sets out the context of their therapeutic application. miRNA (miR)-21 expression in white adipose tissue (WAT) has been associated with obesity. We aimed to analyze miR-21 expression levels in relation to diabetes and obesity to determine the effect that miR-21 mimic has on processes involved in WAT functionality, to dissect the underlying molecular mechanisms, and to study the potential therapeutic application of the miR-21 mimic against obesity. We found higher miR-21 levels in WAT from non-diabetic obese compared to normoweight humans and mice. Moreover, in 3T3-L1 adipocytes, miR-21 mimic affect genes involved in WAT functionality regulation and significantly increase the expression of genes involved in browning and thermogenesis. Interestingly, in vivo treatment with the miR-21 mimic blocked weight gain induced by a high-fat diet in obese mice, without modifying food intake or physical activity. This was associated with metabolic enhancement, WAT browning, and brown adipose tissue (AT) thermogenic programming through vascular endothelial growth factor A (VEGF-A), p53, and transforming growth factor β1 (TGF-β1) signaling pathways. Our findings suggest that miR-21 mimic-based therapy may provide a new opportunity to therapeutically manage obesity and consequently, its associated alterations., Graphical abstract, miR-21 mimic could serve as a potential therapeutic tool to control obesity by delaying energy storage and promoting energy expenditure in adipose tissue.

Background: The course of obesity and type 2 diabetes (T2D) development is highly dependent on adipose tissue (AT) angiogenesis. Moreover, angiogenic microRNAs (miRNAs) play pivotal role in AT functionality. The aim of this study was to analyze the relationship of the human AT miR-221-3p/222-3p cluster and their regulatory network with obesity and T2D. Methods: miR-221-3p/222-3p and their target genes (TG) expression levels were measured in visceral and subcutaneous ATs from patients classified according to their BMI and to their glycemic status with a high degree of insulin resistance (IR) and T2D. In silico analyses of miR-221-3p/222-3p and their TGs were performed to identify relevant signaling pathways. Results: A multivariate analysis, including the simultaneous expression of miR-221-3p and miR-222-3p as dependent variables, showed significant differences considering the variables; tissue depot, obesity, IR and T2D altogether as independent variables. In addition, miRNAs and their TGs were differentially expressed according to obesity degree, glycemic status, and AT depot type. Our in silico analysis showed that miR-221-3p/222-3p cluster TGs are mostly involved in angiogenesis, WNT signaling pathway and apoptosis. Conclusion: These findings suggest that the miR-221-3p/222-3p cluster and their related regulatory networks could represent tangible targets for the management of obesity and associated metabolic disorders

Impaired adipose tissue (AT) lipid handling and inflammation is associated with obesity-related metabolic diseases. Circulating lipopolysaccharides (LPSs) from gut microbiota (metabolic endotoxemia), proposed as a triggering factor for the low-grade inflammation in obesity, might also be responsible for AT dysfunction. Nevertheless, this hypothesis has not been explored in human obesity. To analyze the relationship between metabolic endotoxemia and AT markers for lipogenesis, lipid handling, and inflammation in human obesity, 33 patients with obesity scheduled for surgery were recruited and classified according to their LPS levels. Visceral and subcutaneous AT gene and protein expression were analyzed and adipocyte and AT in vitro assays performed. Subjects with obesity with a high degree of metabolic endotoxemia had lower expression of key genes for AT function and lipogenesis ( SREBP1, FABP4, FASN, and LEP) but higher expression of inflammatory genes in visceral and subcutaneous AT than subjects with low LPS levels. In vitro experiments corroborated that LPS are responsible for adipocyte and AT inflammation and downregulation of PPARG, SCD, FABP4, and LEP expression and LEP secretion. Thus, metabolic endotoxemia influences AT physiology in human obesity by decreasing the expression of factors involved in AT lipid handling and function as well as by increasing inflammation.

microRNAs are promising drug targets in obesity and metabolic disorders. miR-21 expression is upregulated in obese white adipose tissue (WAT); however, its physiological role in WAT has not been fully explored. We aimed to dissect the underlying molecular mechanisms of miR-21 in treating obesity, diabetes, and insulin resistance. We demonstrated, in human and mice, that elevated miR-21 expression is associated with metabolically healthy obesity. miR-21 mimic affected the expression of genes associated with adipogenesis, thermogenesis, and browning in 3T3-L1 adipocytes. In addition, it blocked high fat diet-induced weight gain in obese mice, without modifying food intake or physical activity. This was associated with metabolic enhancements, WAT browning and thermogenic programming, and brown AT induction through VEGF-A, p53, and TGFβ1 signaling pathways. Our findings add a novel role of miR-21 in the regulation of obesity and a potential therapy for both obesity and T2D without altering caloric intake and physical activities.

Objective Expansion of adipose tissue depends on the growth of its vascular network and it has been shown that adipose tissue dysfunction in obese subjects with the metabolic syndrome is associated with decreased angiogenesis. However, some subjects with a high body mass index do not develop metabolic abnormalities associated with obesity. In this study we examined the neovascular properties, expression levels of proteins involved in cellular redox balance and inflammatory cytokines in adipose-derived multipotent mesenchymal cells (ASCs) of subjects with different metabolic profiles. Materials/methods We applied cell culture, flow cytometry, RT-qPCR and ELISA techniques to characterize the ASCs isolated from paired biopsies of visceral (visASCs) and subcutaneous (subASCs) adipose tissue from 39 subjects grouped into normal weight (Nw), obese without metabolic syndrome (NonMS) and with metabolic syndrome (MS). Results VisASCs and subASCs from MS subjects showed a decrease in tubules formation capacity compared to ASCs from NonMS subjects as well as changes in the expression levels of proteins involved in cell redox balance and secretion levels of proteins linked to the senescence-associated secretory phenotype. Deterioration in the neovascular properties of subASCs from the MS subjects was also evident in the decreased levels of VEGF secretion during adipogenesis and in the effects of the conditioned medium on endothelial cell tubule formation. Conclusions Our findings suggest a redox imbalance status in ASCs from subjects with metabolic syndrome and decreased their neovascular function that probably contributes to the vascular insufficiency of adipose depots.

This study aimed to analyze the potential association of different microRNA (miRNA) molecules with both type 2 diabetes (T2D) and obesity and determine their target genes. Quantitative PCR was used to analyze the miR-20b, miR-296, and Let-7f levels in human visceral and subcutaneous adipose tissues (ATs) in relation to obesity and T2D, miRTarBase 4.0 was used for validation of target genes, and the Protein Analysis Through Evolutionary Relationships (PANTHER) Classification System and the Database for Annotation, Visualization and Integrated Discovery (DAVID) were used to annotate the biological processes of the predicted targets. In AT, miR-20b, miR-296, and Let-7f levels were significantly different between normoglycemic subjects and those with T2D. In visceral adipose tissue, miRNA levels were higher in normoglycemic/obesity samples than in T2D/obesity samples. miR-20b-miR-296 and Let-7f target genes that showed significant differences in both ATs in relation to obesity and T2D were CDKN1A, CX3CL1, HIF1A, PPP2R1B, STAT3, and VEGFA. These genes are known to be principally involved in the vascular endothelial growth factor (VEGF) and WNT pathways. This study provides experimental evidence of the possible correlation between AT miR-20b-miR-296-Let-7f with obesity and T2D, which might involve vascular endothelial growth factor and WNT-dependent pathways that are regulated by six different genes, suggesting a novel signaling pathway that could be important for understanding the mechanisms underlying the AT dysfunction associated with obesity and T2D. This work was cofunded by the European Union through the European Regional Development Fund (FEDER) and was supported by grants from the Ministry of Economy and Competitiveness, Institute of Health Carlos III (PI15/01114, PI13/02628; PI12/02355), Ministry of Economy and Knowledge (PI‐CTS‐08181/2011; CTS‐7895/2011), and Consejeria de Salud, Junta de Andalucia (PI‐0092‐2017). RE is under a contract of a “Nicolas Monarde” program from the Servicio Andaluz de Salud.

Background and purpose Glucagon-like peptide-1 (GLP-1) analogues improve glycaemic control in type 2 diabetic (T2D) patients and cause weight loss in obese subjects by as yet unknown mechanisms. We recently demonstrated that the GLP-1 receptor, which is present in adipocytes and the stromal vascular fraction of human adipose tissue (AT), is up-regulated in AT of insulin-resistant morbidly obese subjects compared with healthy lean subjects. The aim of this study was to explore the effects of in vitro and in vivo administration of GLP-1 and its analogues on AT and adipocyte functions from T2D morbidly obese subjects. Experimental approach We analysed the effects of GLP-1 on human AT and isolated adipocytes in vitro and the effects of GLP-1 mimetics on AT of morbidly obese T2D subjects in vivo. Key results GLP-1 down-regulated the expression of lipogenic genes when administered during in vitro differentiation of human adipocytes from morbidly obese patients. GLP-1 also decreased the expression of adipogenic/lipogenic genes in AT explants and mature adipocytes, while increasing that of lipolytic markers and adiponectin. In 3T3-L1 adipocytes, GLP-1 decreased free cytosolic Ca2+ concentration ([Ca2+]i). GLP-1-induced responses were only partially blocked by GLP-1 receptor antagonist exendin (9–39). Moreover, administration of exenatide or liraglutide reduced adipogenic and inflammatory marker mRNA in AT of T2D obese subjects. Conclusions and implications Our data suggest that the beneficial effects of GLP-1 are associated with changes in the adipogenic potential and ability of AT to expand, via activation of the canonical GLP-1 receptor and an additional, as yet unknown, receptor.

MicroRNAs (miRNAs) provide a unique mechanism of gene regulation and play a key role in different pathologies ranging from metabolic diseases to cancer. Thus, they are attractive candidates as therapeutic targets in the clinic. However, delivering miRNAs to specific tissues remains challenging, due to their inherent instability and their low diffusion into tissues, as well as a lack of effective means of delivering them to the cytosols of the specific cells. To overcome these challenges, we constructed a delivery vehicle based on novel gold nanosystems having gemini surfactants which offer a high capacity to induce the miRNAs compression, high stability and cell-entry capability. The synthesis of gold nanoparticles with a positive surface charge, Au@16-Ph-16/miR-21 and Au@16–3-16/miR-21, was carried out in a three-step process. In this method, the hydrogen tetrachloroaurate, sodium tetrahydroborate and 16-Ph-16 or 16–3-16 compounds were used as gold precursor, reducing agent and stabilizers, respectively. The nanoparticles obtained were then covered with miR-21 polymer and were characterized by UV–visible spectroscopy, transmission electron microscopy, atomic force microscopy, dynamic light scattering and zeta potential to measure size and charge distribution. Finally, toxicity was assessed in vivo in mice. Moreover, coherent anti-Stokes Raman spectroscopy and histochemistry analyses showed that Au@16-Ph-16/miR-21 and Au@16–3-16/miR-21 exhibited no toxicity, antimicrobial and biocompatible activities. These nanosystems can be a valuable alternative in therapies associated with diseases where miRNAs play a regulatory role that may be decisive in the improvement or cure of patients. All these characteristics could make of these nanosystems the best potential therapeutic molecules.

Objective The expansion capacity of white adipose tissue influences the distribution of fat depots in the body, the visceral accumulation of which is linked to metabolic syndrome, regardless of the degree of obesity of the subjects. Alterations in the adipose tissue-derived mesenchymal stem cells (ASCs) may contribute to the adipose tissue remodeling associated with metabolic syndrome and impact the regional distribution of adipose tissue by generating inherently dysfunctional adipocytes. Here we examine the expression levels of acetyl-CoA-producing enzymes and their relationship with the lipogenic, antioxidant and oxidative potential of adipocytes generated from visceral ASCs (adipo-visASCs) and subcutaneous ASCs (adipo-subASCs) from subjects with different metabolic profiles. Materials/Methods Paired samples of visceral and subcutaneous adipose tissue were processed to isolate the respective ASCs from normal-weight (Nw) subjects and obese patients with metabolic syndrome (METS) and without METS (NonMETS). qPCR was used to quantify the expression levels of the genes studied in both adipo-ASCs from the patient groups and those generated after silencing by small interfering RNA of acetyl-CoA-producing enzymes. The accumulation of lipids was quantified by absorbance. Results No significant differences in cell yield or CD34+CD31−CD45− ASC percentage were observed between the different patient groups. Unlike adipo-visASCs, adipo-subASCs from METS patients showed a decrease in expression levels of acetyl-CoA-producing enzymes as well as proteins linked to lipogenesis, antioxidant defense and fatty acid oxidation. Transcriptional silencing of acetyl-CoA-producing enzymes in adipo-subASCs reduced lipid accumulation and affected transcription levels of lipogenic and antioxidant defense proteins. Conclusions Adipo-subASCs may be more susceptible than adipo-visASCs to deterioration of the lipogenic, oxidative and antioxidant potential associated with metabolic syndrome. Intrinsic alterations in transcription levels of acetyl-CoA-producing enzymes may contribute to the metabolic reprogramming of adipo-subASCs from METS patients.

Background/Objectives Multiple studies suggest that hypoxia, together with inflammation, could be one of the phenomena involved in the onset and progression of obesity-related insulin resistance. In addition, dysfunction of adipose tissue in obese subjects with metabolic syndrome is associated with decreased angiogenesis. However, some subjects with a high body mass index do not develop metabolic abnormalities associated with obesity. The aim of the current study was to examine the neovascular properties of visceral adipose tissue-derived multipotent mesenchymal cells subjected to hypoxia (hypox-visASCs) from normal-weight subjects (Nw) and obese patients with metabolic syndrome (MS) and without metabolic syndrome (NonMS). Methods This was a 2-year study to enroll subjects who underwent bariatric surgery or cholecystectomy. Eight patients who underwent either bariatric surgery or cholecystectomy (27 patients) participated in the study. Visceral adipose tissue samples from Nw, MS and NonMS subjects were processed by enzymatic digestion. VisASCs cultured under hypoxic conditions were characterized by tubule formation assay, ELISA, flow cytometry, migration rate, and qRT-PCR, and the effects of visASCs-conditioned medium on survival and endothelial cell tubule formation were evaluated. Results Hypox-visASCs from NonMS subjects showed a greater capacity for tubule formation than hypox-visASCs from Nw and MS subjects. The lower percentage of CD140b+/CD44+ and CD140b+/CD184+ cells observed in hypox-visASCs from NonMS subjects compared to MS subjects was accompanied not only by a lower migration rate from the chemotactic effects of stromal cell derived factor 1α, but also by lower levels of NOX5 mRNA expression. While the levels of monocyte chemoattractant protein 1 mRNA expressed by hypox-visASCs correlated positively with the body mass index and waist circumference of the subjects, the concentration of vascular endothelial growth factor present in hypox-visASC-conditioned culture medium decreased significantly with increasing plasma glucose. The survival rate and tubules formed by endothelial cells cultured in hypox-visASC-conditioned medium decreased significantly with increasing homeostasis model assessment to quantify insulin resistance. Conclusions Our results suggest that hypox-visASCs from NonMS subjects could promote healthy adipose tissue expansion, while hypox-visASCs from MS subjects appear to contribute to the decreased angiogenic potential and increased inflammation underlying adipose tissue dysfunction in obesity. Our results emphasize the importance of taking into account not only the BMI but also the metabolic profile of the subjects during the implementation of ASCs-based therapy to promote neovascularization.

Adipose tissue-derived multipotent mesenchymal cells (ASCs) participate in the formation of blood vessels under hypoxic conditions. It is probable that the susceptibility of ASCs to the influence of age and aging-associated pathologies compromises their therapeutic effectiveness depending on the adipose tissue (AT) depot. Our aim was to examine the neovascular potential under hypoxic conditions of ASCs-derived from thymic (thymASCs) and subcutaneous (subASCs) AT from 39 subjects with and without type 2 diabetes mellitus (T2DM) and of different ages who were undergoing coronary bypass surgery (CBS). We confirmed a significant decrease in the percentage of CD34+ CD31- CD45- subASCs in the cell yield of subASCs and in the survival of cultured endothelial cells in the medium conditioned by the hypox-subASCs with increasing patient age, which was not observed in thymASCs. While the length of the tubules generated by hypox-subASCs tended to correlate negatively with patient age, tubule formation capacity of the hypoxic thymASCs increased significantly. Compared with subASCs, thymASCs from subjects over age 65 and without T2DM showed higher cell yield, tubule formation capacity, VEGF secretion levels and the ability to promote endothelial cell survival in their conditioned medium. Deterioration in subASCs neovascular potential relative to thymASCs derived from these subjects was accompanied by higher expression levels of NOX4 mRNA and fibrotic proteins. Our results indicate that thymASCs from patients over age 65 and without T2DM have a higher angiogenic potential than those from the other patient groups, suggesting they may be a good candidate for angiogenic therapy in subjects undergoing CBS. Ministry of Economy and Knowledge, Grant/Award Number: CTS‐7895/2011; This workwas co‐funded by the European Unionthrough the European Regional DevelopmentFund (FEDER) and supported by grants fromthe Ministry of Economy and Competitiveness,Institute of Health Carlos III, Grant/AwardNumber: PI15/01114, PI13/02628 and PI12/02355

The decreased expansion capacity of adipose tissue plays a crucial role in the onset of disorders associated with metabolic syndrome. The aim of this study was to examine the state of adipose tissue-derived mesenchymal stem cells (ASCs) from obese subjects with different metabolic profiles. This was a 2-year study to enroll subjects who underwent bariatric surgery or cholecystectomy. University Hospital. Patients who underwent either bariatric surgery (20 morbidly obese) or cholecystectomy (40 subjects) participated in the study. ASCs were obtained from both visceral and subcutaneous adipose tissue. Adipogenic, fibrotic gene expression was quantified by quantitative polymerase chain reaction; Smad7 and fibroblast growth factor 2 were quantified by western blotting and enzyme-linked immunosorbent assay, respectively. The susceptibility of ASCs to apoptosis, their population doubling time, and their clonogenic potential were evaluated. The worsening metabolic profile of the patients was accompanied by a decrease in the intrinsic levels of adipogenic gene expression, reduced proliferation rate, clonogenic potential, and exportation of fibroblast growth factor 2 to the cell surface of the ASCs derived from both tissues. In addition, the ASCs from patients without metabolic syndrome showed differences in susceptibility to apoptosis and expression of TGFβ-signaling inhibitory protein Smad7 with respect to the ASCs from patients with metabolic syndrome. Our results suggest that the decrease in adipogenic-gene mRNA and clonogenic potential, as well as the accumulation of fibrotic proteins with metabolic alterations, could be a relevant mechanism controlling the number and size of neogenerated adipocytes and involved in alteration of adipose-tissue expansion.

Submitted for publication July 31, 2 2016; accepted for publication Janu Discordant phenotypes, metabolically healthy obese and unhealthy normal-weight individuals, are always interesting to provide important insights into the mechanistic link between adipose tissue dysfunction and associatedmetabolic alterations. Macrophages can release factors that impair the proper activity of the adipose tissue. Thus, studying subcutaneous and visceral adipose tissues, we investigated for the first time the differences inmonocyte/macrophage infiltration, inflammation, and adipogenesis of normal-weight subjects who differed in their degree of metabolic syndrome. The study included 92 normal-weight subjects who differed in their degree of metabolic syndrome. Their anthropometric and biochemical parameters were measured. RNA from subcutaneous and visceral adipose tissues was isolated, and mRNA expression of monocyte/macrophage infiltration (CD68, CD33, ITGAM, CD163, EMR-1, CD206,MerTK, CD64, ITGAX), inflammation (IL-6, tumor necrosis factor alpha [TNFa], IL-10, IL-1b, CCL2, CCL3), and adipogenic and lipogenic capacity markers (PPARgamma, FABP4)weremeasured. Taken together, our data provide evidence of a different degree of macrophage infiltration between the adipose tissues, with a higher monocyte/macrophage infiltration in subcutaneous adipose tissue in metabolically unhealthy normal-weight subjects, whereas visceral adipose tissue remained almost unaffected. An increased macrophage infiltration of adipose tissue and its consequences, such as a decrease in adipogenesis function, may explain why both the obese and normal-weight subjects can develop metabolic diseases or remain healthy. (Translational Research 2016;-:1–12)

Multiple studies have suggested that the reduced differentiation capacity of multipotent adipose tissue-derived mesenchymal stem cells (ASCs) in obese subjects could compromise their use in cell therapy. Our aim was to assess the osteogenic potential of omental ASCs and to examine the status of the isolated CD34negative-enriched fraction of omental-derived ASCs from subjects with different metabolic profiles. Omental ASCs from normal-weight subjects and subjects with or without metabolic syndrome were isolated, and the osteogenic potential of omental ASCs was evaluated. Additionally, osteogenic and clonogenic potential, proliferation rate, mRNA expression levels of proteins involved in redox balance, and fibrotic proteins were examined in the CD34negative-enriched fraction of omental-derived ASCs. Both the omental ASCs and the CD34negative-enriched fraction of omental ASCs from subjects without metabolic syndrome have a greater osteogenic potential than those from subjects with metabolic syndrome. The alkaline phosphatase and osteonectin mRNA were negatively correlated with nicotinamide adenine dinucleotide phosphate oxidase-2 mRNA and the mRNA expression levels of the fibrotic proteins correlated positively with nicotinamide adenine dinucleotide phosphate oxidase-5 mRNA and the homeostasis model assessment. Although the population doubling time was significantly higher in subjects with a body mass index of 25 kg/m2 or greater, only the CD34negative-enriched omental ASC fraction in the subjects with metabolic syndrome had a higher population doubling time than the normal-weight subjects. The osteogenic, clonogenic, fibrotic potential, and proliferation rate observed in vitro suggest that omental ASCs from subjects without metabolic syndrome are more suitable for therapeutic osteogenic applications than those from subjects with metabolic syndrome.

Glucagon-like peptide-1 (GLP-1) analogues improve glycaemic control in type 2 diabetic (T2D) patients and cause weight loss in obese subjects by as yet unknown mechanisms. We recently demonstrated that the GLP-1 receptor, which is present in adipocytes and the stromal vascular fraction of human adipose tissue (AT), is up-regulated in AT of insulin-resistant morbidly obese subjects compared with healthy lean subjects. The aim of this study was to explore the effects of in vitro and in vivo administration of GLP-1 and its analogues on AT and adipocyte functions from T2D morbidly obese subjects.We analysed the effects of GLP-1 on human AT and isolated adipocytes in vitro and the effects of GLP-1 mimetics on AT of morbidly obese T2D subjects in vivo.GLP-1 down-regulated the expression of lipogenic genes when administered during in vitro differentiation of human adipocytes from morbidly obese patients. GLP-1 also decreased the expression of adipogenic/lipogenic genes in AT explants and mature adipocytes, while increasing that of lipolytic markers and adiponectin. In 3T3-L1 adipocytes, GLP-1 decreased free cytosolic Ca2+ concentration ([Ca2+]i). GLP-1-induced responses were only partially blocked by GLP-1 receptor antagonist exendin (9–39). Moreover, administration of exenatide or liraglutide reduced adipogenic and inflammatory marker mRNA in AT of T2D obese subjects.Our data suggest that the beneficial effects of GLP-1 are associated with changes in the adipogenic potential and ability of AT to expand, via activation of the canonical GLP-1 receptor and an additional, as yet unknown, receptor.

et al., [Objective]: This study aimed to define the potential role of PTHrP on adipogenic regulation and to analyze its relationship with obesity and insulin resistance. [Design]: This was a cross-sectional study in which visceral (VAT) and subcutaneous (SAT) adipose tissue were extracted from 19 morbidly obese, 10 obese, and 10 lean subjects. PTHrP mRNA levels were measured in VAT and SAT. VAT mesenchymal stem cells and 3T3-L1 cells were differentiated into adipocytes in presence or absence of PTHrP siRNA. PTHrP mRNA and protein levels as well as adipogenic markers were evaluated by Western blotting or qPCR. Immunohistochemistry and immunofluorescence procedures were used for PTHrP intracellular localization. [Results]: Both human VAT and SAT express PTHrP protein mainly in the nucleolar compartment of stromal vascular fraction cells. The highest levels of PTHrP mRNA and protein expression were detected in undifferentiated mesenchymal cells and progressively decreased during adipogenesis. Remarkably, adipogenic differentiation in human mesenchymal stem cells (A-hMSC) was significantly impaired in a pthrp knockdown. PTHrP seems to be related to obesity-associated insulin resistance (IR), given that we found that PTHrP mRNA expression was higher in VAT from morbidly obese with a low IR degree (MO-L-IR) subjects than those from morbidly obese with a high IR degree (MO-H-IR) and lean subjects, and correlated positively with body mass index and hip circumference. We also found that A-hMSC from MO-L-IRs displayed higher adipogenic capacity than those from both MO-H-IRs and leans. In addition, adipogenesis was impaired in VAT from MO-H-IRs, given that mRNA expression levels of key adipogenic regulators were lower than those from MO-L-IR subjects. [Conclusions]: PTHrP could be a potential new therapeutic target for the reprograming of adipogenesis and adipose tissue expansion, thus possibly ameliorating the metabolic syndrome in obese subjects., This work was supported in part by grants from the Instituto de Salud Carlos III [PI12/02355, PI10/01947, PI13/02628, CP04/00133, PI10/01947, PS09/01060, PS09/00997], Servicio Andaluz de Salud [PI0255/2007]. CTS-7895 and CTS 08181 from the Consejería de Economía e Innovación, Ciencia y Empleo, Junta de Andalucia, by grant SAF-2012-33014 (to B.P.) from the Ministerio de Economia y Competitividad, Spain. L. Garrido-Sánchez is supported by fellowships from the ISCIII “Miguel Servet I” [CP13/00188]. M.M Roca-Rodríguez is supported by a fellowship from the Programa Rio Hortega (CM11/00030). R. El Bekay is supported by fellowships from the ISCIII “Miguel Servet II” [CPII13/00041]. L Garrido-Sánchez acknowledges support from the “Miguel Servet” program (CP13/00188) from the Fondo de Investigación Sanitaria (FIS). M. Gómez-Serrano is supported by a fellowship from Ayuda a la Formación de Personal Investigador de la Universidad Autónoma de Madrid (FPI-UAM) Program.

Discordant phenotypes, metabolically healthy obese and unhealthy normal-weight individuals, are always interesting to provide important insights into the mechanistic link between adipose tissue dysfunction and associated metabolic alterations. Macrophages can release factors that impair the proper activity of the adipose tissue. Thus, studying subcutaneous and visceral adipose tissues, we investigated for the first time the differences in monocyte/macrophage infiltration, inflammation, and adipogenesis of normal-weight subjects who differed in their degree of metabolic syndrome. The study included 92 normal-weight subjects who differed in their degree of metabolic syndrome. Their anthropometric and biochemical parameters were measured. RNA from subcutaneous and visceral adipose tissues was isolated, and mRNA expression of monocyte/macrophage infiltration (CD68, CD33, ITGAM, CD163, EMR-1, CD206, MerTK, CD64, ITGAX), inflammation (IL-6, tumor necrosis factor alpha [TNFα], IL-10, IL-1b, CCL2, CCL3), and adipogenic and lipogenic capacity markers (PPARgamma, FABP4) were measured. Taken together, our data provide evidence of a different degree of macrophage infiltration between the adipose tissues, with a higher monocyte/macrophage infiltration in subcutaneous adipose tissue in metabolically unhealthy normal-weight subjects, whereas visceral adipose tissue remained almost unaffected. An increased macrophage infiltration of adipose tissue and its consequences, such as a decrease in adipogenesis function, may explain why both the obese and normal-weight subjects can develop metabolic diseases or remain healthy.