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De Fano M, Bartolini D, Tortoioli C, Vermigli C, Malara M, Galli F, Murdolo G. Adipose Tissue Plasticity in Response to Pathophysiological Cues: A Connecting Link between Obesity and Its Associated Comorbidities. Int J Mol Sci 2022; 23:ijms23105511. [PMID: 35628322 PMCID: PMC9141504 DOI: 10.3390/ijms23105511] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/10/2022] [Accepted: 05/13/2022] [Indexed: 12/10/2022] Open
Abstract
Adipose tissue (AT) is a remarkably plastic and active organ with functional pleiotropism and high remodeling capacity. Although the expansion of fat mass, by definition, represents the hallmark of obesity, the dysregulation of the adipose organ emerges as the forefront of the link between adiposity and its associated metabolic and cardiovascular complications. The dysfunctional fat displays distinct biological signatures, which include enlarged fat cells, low-grade inflammation, impaired redox homeostasis, and cellular senescence. While these events are orchestrated in a cell-type, context-dependent and temporal manner, the failure of the adipose precursor cells to form new adipocytes appears to be the main instigator of the adipose dysregulation, which, ultimately, poses a deleterious milieu either by promoting ectopic lipid overspill in non-adipose targets (i.e., lipotoxicity) or by inducing an altered secretion of different adipose-derived hormones (i.e., adipokines and lipokines). This “adipocentric view” extends the previous “expandability hypothesis”, which implies a reduced plasticity of the adipose organ at the nexus between unhealthy fat expansion and the development of obesity-associated comorbidities. In this review, we will briefly summarize the potential mechanisms by which adaptive changes to variations of energy balance may impair adipose plasticity and promote fat organ dysfunction. We will also highlight the conundrum with the perturbation of the adipose microenvironment and the development of cardio-metabolic complications by focusing on adipose lipoxidation, inflammation and cellular senescence as a novel triad orchestrating the conspiracy to adipose dysfunction. Finally, we discuss the scientific rationale for proposing adipose organ plasticity as a target to curb/prevent adiposity-linked cardio-metabolic complications.
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Affiliation(s)
- Michelatonio De Fano
- Department of Internal Medicine, Endocrinology and Metabolism, Azienda Ospedaliera Santa Maria Misericordia, Ospedale di Perugia, Piazzale Gambuli, 06081 Perugia, Italy; (M.D.F.); (C.T.); (C.V.); (M.M.)
| | - Desirèe Bartolini
- Department of Pharmaceutical Sciences, Human Anatomy Laboratory, University of Perugia, 06132 Perugia, Italy; (D.B.); (F.G.)
| | - Cristina Tortoioli
- Department of Internal Medicine, Endocrinology and Metabolism, Azienda Ospedaliera Santa Maria Misericordia, Ospedale di Perugia, Piazzale Gambuli, 06081 Perugia, Italy; (M.D.F.); (C.T.); (C.V.); (M.M.)
| | - Cristiana Vermigli
- Department of Internal Medicine, Endocrinology and Metabolism, Azienda Ospedaliera Santa Maria Misericordia, Ospedale di Perugia, Piazzale Gambuli, 06081 Perugia, Italy; (M.D.F.); (C.T.); (C.V.); (M.M.)
| | - Massimo Malara
- Department of Internal Medicine, Endocrinology and Metabolism, Azienda Ospedaliera Santa Maria Misericordia, Ospedale di Perugia, Piazzale Gambuli, 06081 Perugia, Italy; (M.D.F.); (C.T.); (C.V.); (M.M.)
| | - Francesco Galli
- Department of Pharmaceutical Sciences, Human Anatomy Laboratory, University of Perugia, 06132 Perugia, Italy; (D.B.); (F.G.)
| | - Giuseppe Murdolo
- Department of Internal Medicine, Endocrinology and Metabolism, Azienda Ospedaliera Santa Maria Misericordia, Ospedale di Perugia, Piazzale Gambuli, 06081 Perugia, Italy; (M.D.F.); (C.T.); (C.V.); (M.M.)
- Correspondence: ; Tel.: +39-(0)75-578-3301; Fax: +39-75-573-0855
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Kornej J, Lin H, Trinquart L, Jackson CR, Ko D, Benjamin EJ, Preis SR. Neck Circumference and Risk of Incident Atrial Fibrillation in the Framingham Heart Study. J Am Heart Assoc 2022; 11:e022340. [PMID: 35156385 PMCID: PMC9245798 DOI: 10.1161/jaha.121.022340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Increased neck circumference, a proxy for upper‐body subcutaneous fat, is associated with cardiovascular risk and metabolic risk factors, accounting for body mass index (BMI) and waist circumference. The association between neck circumference and incident atrial fibrillation (AF) is unclear. The aim of current study was to evaluate the association between neck circumference and incident AF. Methods and Results We selected participants from the Framingham Heart Study aged ≥55 years without diagnosed AF and with available neck circumference, BMI, and waist circumference measurements. We defined high neck circumference as ≥14 inches in women and ≥17 inches in men on the basis of the Contal and O’Quigley changepoint method. We used Fine‐Gray models to estimate subdistribution hazards ratios (sHRs) for the association between neck circumference and incident AF accounting for the competing risk of death. We adjusted models for clinical risk factors. We then additionally adjusted separately for BMI, waist circumference, and height/weight. The study sample included 4093 participants (mean age 64±7 years, 55% female). During 11.2±5.7 mean years of follow‐up, incident AF occurred in 571 participants. High neck circumference was associated with incident AF (sHR for high versus low: 1.58; 95% CI, 1.32–1.90, P<0.0001). The association remained significant after adjustment for BMI (sHR, 1.51; 95% CI, 1.21–1.89; P=0.0003), waist circumference (sHR, 1.47; 95% CI, 1.18–1.83; P<0.0001), and height/weight (sHR, 1.37; 95% CI, 1.09–1.72; P=0.007). Conclusions High neck circumference was associated with incident AF adjusting for traditional adiposity measures such as BMI and waist circumference.
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Affiliation(s)
- Jelena Kornej
- National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study Framingham MA
- Section of Cardiovascular Medicine Department of Medicine Boston University School of Medicine Boston MA
| | - Honghuang Lin
- National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study Framingham MA
- Section of Computational Biomedicine Department of Medicine Boston University School of Medicine Boston MA
| | - Ludovic Trinquart
- National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study Framingham MA
- Department of Biostatistics Boston University School of Public Health Boston MA
| | | | - Darae Ko
- Section of Cardiovascular Medicine Department of Medicine Boston University School of Medicine Boston MA
| | - Emelia J. Benjamin
- National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study Framingham MA
- Section of Cardiovascular Medicine Department of Medicine Boston University School of Medicine Boston MA
- Department of Epidemiology Boston University School of Public Health Boston MA
| | - Sarah R. Preis
- National Heart, Lung, and Blood Institute’s and Boston University’s Framingham Heart Study Framingham MA
- Department of Biostatistics Boston University School of Public Health Boston MA
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Silva AAGDO, Araujo LFD, Diniz MDFHS, Lotufo PA, Bensenor IM, Barreto SM, Giatti L. Neck Circumference and 10-Year Cardiovascular Risk at the Baseline of the ELSA-Brasil Study: Difference by Sex. Arq Bras Cardiol 2020; 115:840-848. [PMID: 33295446 PMCID: PMC8452203 DOI: 10.36660/abc.20190289] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 10/29/2019] [Indexed: 12/14/2022] Open
Abstract
Fundamento: A circunferência do pescoço (CP) é uma medida indireta do tecido adiposo subcutâneo da parte superior do corpo, apontada como um preditor independente de doenças cardiometabólicas. Objetivos: Verificar a associação entre a CP e o risco cardiovascular em 10 anos (risco de doença cardiovascular [DCV] em 10 anos) em homens e mulheres separadamente. Métodos: Análise seccional com inclusão de 13.920 participantes da linha de base do Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil). A associação entre a CP (utilizada como variável contínua e agregada em quartis) e o risco de DCV em 10 anos, estimado pelo Framingham Global Risk Score (FGRS), foi investigada por meio de modelos lineares generalizados após ajustes por características sociodemográficas, comportamentos em saúde, índice de massa corporal e circunferência da cintura. O nível de significância estatístico adotado foi de 5%. Resultados: A média da CP foi de 39,5 cm (desvio-padrão [DP] de ± 3,6) nos homens e 34,0 cm (DP de ±2,9) nas mulheres. Após ajustes, o aumento de 1 cm na CP foi associado ao incremento de 3% (IC 95%: 1,02 a 1,03) e 5% (IC 95%: 1,04 a 1,06) na média aritmética do risco de DCV em homens e mulheres, respectivamente. No último quartil da CP, homens e mulheres apresentaram um incremento de 18% (IC 95%: 1,13 a 1,24) e 35% (IC 95%: 1,28 a 1,43), respectivamente, na média aritmética do risco de DCV após ajustes. Conclusões: Verificamos associação positiva e independente entre a CP e o risco de DCV em 10 anos. Resultados sugerem que a CP pode contribuir para a predição de risco cardiovascular além daquele observado pelas medidas antropométricas clássicas.
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Affiliation(s)
| | | | | | | | | | | | - Luana Giatti
- Universidade Federal de Minas Gerais, Belo Horizonte, MG - Brasil
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Longo M, Raciti GA, Zatterale F, Parrillo L, Desiderio A, Spinelli R, Hammarstedt A, Hedjazifar S, Hoffmann JM, Nigro C, Mirra P, Fiory F, Formisano P, Miele C, Smith U, Beguinot F. Epigenetic modifications of the Zfp/ZNF423 gene control murine adipogenic commitment and are dysregulated in human hypertrophic obesity. Diabetologia 2018; 61:369-380. [PMID: 29067487 PMCID: PMC6448963 DOI: 10.1007/s00125-017-4471-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 09/08/2017] [Indexed: 12/18/2022]
Abstract
AIMS/HYPOTHESIS Subcutaneous adipocyte hypertrophy is associated with insulin resistance and increased risk of type 2 diabetes, and predicts its future development independent of obesity. In humans, subcutaneous adipose tissue hypertrophy is a consequence of impaired adipocyte precursor cell recruitment into the adipogenic pathway rather than a lack of precursor cells. The zinc finger transcription factor known as zinc finger protein (ZFP) 423 has been identified as a major determinant of pre-adipocyte commitment and maintained white adipose cell function. Although its levels do not change during adipogenesis, ectopic expression of Zfp423 in non-adipogenic murine cells is sufficient to activate expression of the gene encoding peroxisome proliferator-activated receptor γ (Pparγ; also known as Pparg) and increase the adipogenic potential of these cells. We investigated whether the Zfp423 gene is under epigenetic regulation and whether this plays a role in the restricted adipogenesis associated with hypertrophic obesity. METHODS Murine 3T3-L1 and NIH-3T3 cells were used as fibroblasts committed and uncommitted to the adipocyte lineage, respectively. Human pre-adipocytes were isolated from the stromal vascular fraction of subcutaneous adipose tissue of 20 lean non-diabetic individuals with a wide adipose cell size range. mRNA levels were measured by quantitative real-time PCR, while methylation levels were analysed by bisulphite sequencing. Chromatin structure was analysed by micrococcal nuclease protection assay, and DNA-methyltransferases were chemically inhibited by 5-azacytidine. Adipocyte differentiation rate was evaluated by Oil Red O staining. RESULTS Comparison of uncommitted (NIH-3T3) and committed (3T3-L1) adipose precursor cells revealed that Zfp423 expression increased (p < 0.01) in parallel with the ability of the cells to differentiate into mature adipocytes owing to both decreased promoter DNA methylation (p < 0.001) and nucleosome occupancy (nucleosome [NUC] 1 p < 0.01; NUC2 p < 0.001) in the 3T3-L1 compared with NIH-3T3 cells. Interestingly, non-adipogenic epigenetic profiles can be reverted in NIH-3T3 cells as 5-azacytidine treatment increased Zfp423 mRNA levels (p < 0.01), reduced DNA methylation at a specific CpG site (p < 0.01), decreased nucleosome occupancy (NUC1, NUC2: p < 0.001) and induced adipocyte differentiation (p < 0.05). These epigenetic modifications can also be initiated in response to changes in the pre-adipose cell microenvironment, in which bone morphogenetic protein 4 (BMP4) plays a key role. We finally showed that, in human adipocyte precursor cells, impaired epigenetic regulation of zinc nuclear factor (ZNF)423 (the human orthologue of murine Zfp423) was associated with inappropriate subcutaneous adipose cell hypertrophy. As in NIH-3T3 cells, the normal ZNF423 epigenetic profile was rescued by 5-azacytidine exposure. CONCLUSIONS/INTERPRETATION Our results show that epigenetic events regulate the ability of precursor cells to commit and differentiate into mature adipocytes by modulating ZNF423, and indicate that dysregulation of these mechanisms accompanies subcutaneous adipose tissue hypertrophy in humans.
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Affiliation(s)
- Michele Longo
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Gregory A Raciti
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Federica Zatterale
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Luca Parrillo
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Antonella Desiderio
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Rosa Spinelli
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Ann Hammarstedt
- Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Shahram Hedjazifar
- Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Jenny M Hoffmann
- Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Cecilia Nigro
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Paola Mirra
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Francesca Fiory
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Pietro Formisano
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Claudia Miele
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy
| | - Ulf Smith
- Lundberg Laboratory for Diabetes Research, Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Francesco Beguinot
- URT Genomics of Diabetes-IEOS, CNR & Department of Translational Medicine, Federico II University of Naples, Via Pansini 5, 80131, Naples, Italy.
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Mulder P, Morrison MC, Verschuren L, Liang W, van Bockel JH, Kooistra T, Wielinga PY, Kleemann R. Reduction of obesity-associated white adipose tissue inflammation by rosiglitazone is associated with reduced non-alcoholic fatty liver disease in LDLr-deficient mice. Sci Rep 2016; 6:31542. [PMID: 27545964 PMCID: PMC4992869 DOI: 10.1038/srep31542] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 07/18/2016] [Indexed: 12/14/2022] Open
Abstract
Obesity is associated with chronic low-grade inflammation that drives the development of metabolic diseases, including non-alcoholic fatty liver disease (NAFLD). We recently showed that white adipose tissue (WAT) constitutes an important source of inflammatory factors. Hence, interventions that attenuate WAT inflammation may reduce NAFLD development. Male LDLr-/- mice were fed a high-fat diet (HFD) for 9 weeks followed by 7 weeks of HFD with or without rosiglitazone. Effects on WAT inflammation and NAFLD development were analyzed using biochemical and (immuno)histochemical techniques, combined with gene expression analyses. Nine weeks of HFD feeding induced obesity and WAT inflammation, which progressed gradually until the end of the study. Rosiglitazone fully blocked progression of WAT inflammation and activated PPARγ significantly in WAT. Rosiglitazone intervention did not activate PPARγ in liver, but improved liver histology and counteracted the expression of genes associated with severe NAFLD in humans. Rosiglitazone reduced expression of pro-inflammatory factors in WAT (TNF-α, leptin) and increased expression of adiponectin, which was reflected in plasma. Furthermore, rosiglitazone lowered circulating levels of pro-inflammatory saturated fatty acids. Together, these observations provide a rationale for the observed indirect hepatoprotective effects and suggest that WAT represents a promising therapeutic target for the treatment of obesity-associated NAFLD.
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Affiliation(s)
- Petra Mulder
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Zernikedreef 9, 2333 CK Leiden, The Netherlands.,Department of Vascular Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - Martine C Morrison
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Zernikedreef 9, 2333 CK Leiden, The Netherlands
| | - Lars Verschuren
- Department of Microbiology and Systems Biology, Netherlands Organization for Applied Scientific Research (TNO), 3704 HE, Zeist, The Netherlands
| | - Wen Liang
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Zernikedreef 9, 2333 CK Leiden, The Netherlands
| | - J Hajo van Bockel
- Department of Vascular Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
| | - Teake Kooistra
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Zernikedreef 9, 2333 CK Leiden, The Netherlands
| | - Peter Y Wielinga
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Zernikedreef 9, 2333 CK Leiden, The Netherlands
| | - Robert Kleemann
- Department of Metabolic Health Research, Netherlands Organization for Applied Scientific Research (TNO), Zernikedreef 9, 2333 CK Leiden, The Netherlands.,Department of Vascular Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands
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Murdolo G, Bartolini D, Tortoioli C, Piroddi M, Iuliano L, Galli F. Lipokines and oxysterols: novel adipose-derived lipid hormones linking adipose dysfunction and insulin resistance. Free Radic Biol Med 2013; 65:811-820. [PMID: 23954331 DOI: 10.1016/j.freeradbiomed.2013.08.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 08/07/2013] [Accepted: 08/08/2013] [Indexed: 02/07/2023]
Abstract
The expansion of adipose tissue (AT) is, by definition, a hallmark of obesity. However, not all increases in fat mass are associated with pathophysiological cues. Indeed, whereas a "healthy" fat mass accrual, mainly in the subcutaneous depots, preserves metabolic homeostasis, explaining the occurrence of the metabolically healthy obese phenotype, "unhealthy" AT expansion is importantly associated with insulin resistance/type 2 diabetes and the metabolic syndrome. The development of a dysfunctional adipose organ may find mechanistic explanation in a reduced ability to recruit new and functional (pre)adipocytes from undifferentiated precursor cells. Such a failure of the adipogenic process underlies the "AT expandability" paradigm. The inability of AT to expand further to store excess nutrients, rather than obesity per se, induces a diabetogenic milieu by promoting the overflow and the ectopic deposition of fatty acids in insulin-dependent organs (i.e., lipotoxicity), the secretion of various metabolically detrimental adipose-derived hormones (i.e., adipokines and lipokines), and the occurrence of local and systemic inflammation and oxidative stress. Hitherto, fatty acids (i.e., lipokines) and the oxidation by-products of cholesterol and polyunsaturated fatty acids, such as nonenzymatic oxysterols and reactive aldehyde species, respectively, emerge as key modulators of (pre)adipocyte signaling through Wnt/β-catenin and MAPK pathways and potential regulators of glucose homeostasis. These and other mechanistic insights linking adipose dysfunction, oxidative stress, and impairment of glucose homeostasis are discussed in this review article, which focuses on adipose peroxidation as a potential instigator of, and a putative therapeutic target for, obesity-associated metabolic dysfunctions.
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Affiliation(s)
- Giuseppe Murdolo
- Department of Internal Medicine, Assisi Hospital, I-06081 Assisi, Perugia, Italy; Section of Internal Medicine, Endocrine, and Metabolic Sciences, Italy.
| | - Desirée Bartolini
- Section of Applied Biochemistry and Nutritional Sciences, Department of Internal Medicine, Perugia University, Perugia, Italy
| | | | - Marta Piroddi
- Section of Applied Biochemistry and Nutritional Sciences, Department of Internal Medicine, Perugia University, Perugia, Italy
| | - Luigi Iuliano
- Unit of Vascular Medicine, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
| | - Francesco Galli
- Section of Applied Biochemistry and Nutritional Sciences, Department of Internal Medicine, Perugia University, Perugia, Italy
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Villarroel P, Reyes M, Fuentes C, Segovia MP, Tobar N, Villalobos E, Martínez J, Hugo E, Ben-jonathan N, Cifuentes M. Adipogenic effect of calcium sensing receptor activation. Mol Cell Biochem 2013; 384:139-45. [DOI: 10.1007/s11010-013-1791-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
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Hammarstedt A, Hedjazifar S, Jenndahl L, Gogg S, Grünberg J, Gustafson B, Klimcakova E, Stich V, Langin D, Laakso M, Smith U. WISP2 regulates preadipocyte commitment and PPARγ activation by BMP4. Proc Natl Acad Sci U S A 2013; 110:2563-8. [PMID: 23359679 DOI: 10.1073/pnas.1211255110] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Inability to recruit new adipose cells following weight gain leads to inappropriate enlargement of existing cells (hypertrophic obesity) associated with inflammation and a dysfunctional adipose tissue. We found increased expression of WNT1 inducible signaling pathway protein 2 (WISP2) and other markers of WNT activation in human abdominal s.c. adipose tissue characterized by hypertrophic obesity combined with increased visceral fat accumulation and insulin resistance. WISP2 activation in the s.c. adipose tissue, but not in visceral fat, identified the metabolic syndrome in equally obese individuals. WISP2 is a novel adipokine, highly expressed and secreted by adipose precursor cells. Knocking down WISP2 induced spontaneous differentiation of 3T3-L1 and human preadipocytes and allowed NIH 3T3 fibroblasts to become committed to the adipose lineage by bone morphogenetic protein 4 (BMP4). WISP2 forms a cytosolic complex with the peroxisome proliferator-activated receptor γ (PPARγ) transcriptional activator zinc finger protein 423 (Zfp423), and this complex is dissociated by BMP4 in a SMAD-dependent manner, thereby allowing Zfp423 to enter the nucleus, activate PPARγ, and commit the cells to the adipose lineage. The importance of intracellular Wisp2 protein for BMP4-induced adipogenic commitment and PPARγ activation was verified by expressing a mutant Wisp2 protein lacking the endoplasmic reticulum signal and secretion sequence. Secreted Wnt/Wisp2 also inhibits differentiation and PPARγ activation, albeit not through Zfp423 nuclear translocation. Thus adipogenic commitment and differentiation is regulated by the cross-talk between BMP4 and canonical WNT signaling and where WISP2 plays a key role. Furthermore, they link WISP2 with hypertrophic obesity and the metabolic syndrome.
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Hammarstedt A, Graham TE, Kahn BB. Adipose tissue dysregulation and reduced insulin sensitivity in non-obese individuals with enlarged abdominal adipose cells. Diabetol Metab Syndr 2012; 4:42. [PMID: 22992414 PMCID: PMC3523053 DOI: 10.1186/1758-5996-4-42] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 09/17/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Obesity contributes to Type 2 diabetes by promoting systemic insulin resistance. Obesity causes features of metabolic dysfunction in the adipose tissue that may contribute to later impairments of insulin action in skeletal muscle and liver; these include reduced insulin-stimulated glucose transport, reduced expression of GLUT4, altered expression of adipokines, and adipocyte hypertrophy. Animal studies have shown that expansion of adipose tissue alone is not sufficient to cause systemic insulin resistance in the absence of adipose tissue metabolic dysfunction. To determine if this holds true for humans, we studied the relationship between insulin resistance and markers of adipose tissue dysfunction in non-obese individuals. METHOD 32 non-obese first-degree relatives of Type 2 diabetic patients were recruited. Glucose tolerance was determined by an oral glucose tolerance test and insulin sensitivity was measured with the hyperinsulinaemic-euglycaemic clamp. Blood samples were collected and subcutaneous abdominal adipose tissue biopsies obtained for gene/protein expression and adipocyte cell size measurements. RESULTS Our findings show that also in non-obese individuals low insulin sensitivity is associated with signs of adipose tissue metabolic dysfunction characterized by low expression of GLUT4, altered adipokine profile and enlarged adipocyte cell size. In this group, insulin sensitivity is positively correlated to GLUT4 mRNA (R = 0.49, p = 0.011) and protein (R = 0.51, p = 0.004) expression, as well as with circulating adiponectin levels (R = 0.46, 0 = 0.009). In addition, insulin sensitivity is inversely correlated to circulating RBP4 (R = -0.61, 0 = 0.003) and adipocyte cell size (R = -0.40, p = 0.022). Furthermore, these features are inter-correlated and also associated with other clinical features of the metabolic syndrome in the absence of obesity. No association could be found between the hypertrophy-associated adipocyte dysregulation and HIF-1alpha in this group of non-obese individuals. CONCLUSIONS In conclusion, these findings support the concept that it is not obesity per se, but rather metabolic dysfunction of adipose tissue that is associated with systemic insulin resistance and the metabolic syndrome.
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Affiliation(s)
- Ann Hammarstedt
- The Lundberg Laboratory for Diabetes Research, Center of Excellence for Metabolic and Cardiovascular Research, Department of Molecular and Clinical Medicine, the Sahlgrenska Academy at the University of Gothenburg, Gothenburg, SE-413 45, Sweden
| | - Timothy E Graham
- Division of Endocrinology, Diabetes and Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Barbara B Kahn
- Division of Endocrinology, Diabetes and Medicine, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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Chatterjee TK, Idelman G, Blanco V, Blomkalns AL, Piegore MG, Weintraub DS, Kumar S, Rajsheker S, Manka D, Rudich SM, Tang Y, Hui DY, Bassel-Duby R, Olson EN, Lingrel JB, Ho SM, Weintraub NL. Histone deacetylase 9 is a negative regulator of adipogenic differentiation. J Biol Chem 2011; 286:27836-47. [PMID: 21680747 DOI: 10.1074/jbc.m111.262964] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Differentiation of preadipocytes into mature adipocytes capable of efficiently storing lipids is an important regulatory mechanism in obesity. Here, we examined the involvement of histone deacetylases (HDACs) and histone acetyltransferases (HATs) in the regulation of adipogenesis. We find that among the various members of the HDAC and HAT families, only HDAC9 exhibited dramatic down-regulation preceding adipogenic differentiation. Preadipocytes from HDAC9 gene knock-out mice exhibited accelerated adipogenic differentiation, whereas HDAC9 overexpression in 3T3-L1 preadipocytes suppressed adipogenic differentiation, demonstrating its direct role as a negative regulator of adipogenesis. HDAC9 expression was higher in visceral as compared with subcutaneous preadipocytes, negatively correlating with their potential to undergo adipogenic differentiation in vitro. HDAC9 localized in the nucleus, and its negative regulation of adipogenesis segregates with the N-terminal nuclear targeting domain, whereas the C-terminal deacetylase domain is dispensable for this function. HDAC9 co-precipitates with USF1 and is recruited with USF1 at the E-box region of the C/EBPα gene promoter in preadipocytes. Upon induction of adipogenic differentiation, HDAC9 is down-regulated, leading to its dissociation from the USF1 complex, whereas p300 HAT is up-regulated to allow its association with USF1 and accumulation at the E-box site of the C/EBPα promoter in differentiated adipocytes. This reciprocal regulation of HDAC9 and p300 HAT in the USF1 complex is associated with increased C/EBPα expression, a master regulator of adipogenic differentiation. These findings provide new insights into mechanisms of adipogenic differentiation and document a critical regulatory role for HDAC9 in adipogenic differentiation through a deacetylase-independent mechanism.
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Affiliation(s)
- Tapan K Chatterjee
- Department of Internal Medicine, Division of Cardiovascular Diseases, University of Cincinnati, Cincinnati, Ohio 45267, USA.
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Chakrabarti SK, Wen Y, Dobrian AD, Cole BK, Ma Q, Pei H, Williams MD, Bevard MH, Vandenhoff GE, Keller SR, Gu J, Nadler JL. Evidence for activation of inflammatory lipoxygenase pathways in visceral adipose tissue of obese Zucker rats. Am J Physiol Endocrinol Metab 2011; 300:E175-87. [PMID: 20978234 PMCID: PMC3023204 DOI: 10.1152/ajpendo.00203.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Central obesity is associated with low-grade inflammation that promotes type 2 diabetes and cardiovascular disease in obese individuals. The 12- and 5-lipoxygenase (12-LO and 5-LO) enzymes have been linked to inflammatory changes, leading to the development of atherosclerosis. 12-LO has also been linked recently to inflammation and insulin resistance in adipocytes. We analyzed the expression of LO and proinflammatory cytokines in adipose tissue and adipocytes in obese Zucker rats, a widely studied genetic model of obesity, insulin resistance, and the metabolic syndrome. mRNA expression of 12-LO, 5-LO, and 5-LO-activating protein (FLAP) was upregulated in adipocytes and adipose tissue from obese Zucker rats compared with those from lean rats. Concomitant with increased LO gene expression, the 12-LO product 12-HETE and the 5-LO products 5-HETE and leukotriene B4 (LTB4) were also increased in adipocytes. Furthermore, upregulation of key proinflammatory markers interleukin (IL)-6, TNFα, and monocyte chemoattractant protein-1 were observed in adipocytes isolated from obese Zucker rats. Immunohistochemistry indicated that the positive 12-LO staining in adipose tissue represents cells in addition to adipocytes. This was confirmed by Western blotting in stromal vascular fractions. These changes were in part reversed by the novel anti-inflammatory drug lisofylline (LSF). LSF also reduced p-STAT4 in visceral adipose tissue from obese Zucker rats and improved the metabolic profile, reducing fasting plasma glucose and increasing insulin sensitivity in obese Zucker rats. In 3T3-L1 adipocytes, LSF abrogated the inflammatory response induced by LO products. Thus, therapeutic agents reducing LO or STAT4 activation may provide novel tools to reduce obesity-induced inflammation.
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