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Pescador N, Francisco V, Vázquez P, Esquinas EM, González-Páramos C, Valdecantos MP, García-Martínez I, Urrutia AA, Ruiz L, Escalona-Garrido C, Foretz M, Viollet B, Fernández-Moreno MÁ, Calle-Pascual AL, Obregón MJ, Aragonés J, Valverde ÁM. Metformin reduces macrophage HIF1α-dependent proinflammatory signaling to restore brown adipocyte function in vitro. Redox Biol 2021; 48:102171. [PMID: 34736121 PMCID: PMC8577482 DOI: 10.1016/j.redox.2021.102171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 12/25/2022] Open
Abstract
Therapeutic potential of metformin in obese/diabetic patients has been associated to its ability to combat insulin resistance. However, it remains largely unknown the signaling pathways involved and whether some cell types are particularly relevant for its beneficial effects. M1-activation of macrophages by bacterial lipopolysaccharide (LPS) promotes a paracrine activation of hypoxia-inducible factor-1α (HIF1α) in brown adipocytes which reduces insulin signaling and glucose uptake, as well as β-adrenergic sensitivity. Addition of metformin to M1-polarized macrophages blunted these signs of brown adipocyte dysfunction. At the molecular level, metformin inhibits an inflammatory program executed by HIF1α in macrophages by inducing its degradation through the inhibition of mitochondrial complex I activity, thereby reducing oxygen consumption in a reactive oxygen species (ROS)-independent manner. In obese mice, metformin reduced inflammatory features in brown adipose tissue (BAT) such as macrophage infiltration, proinflammatory signaling and gene expression, and restored the response to cold exposure. In conclusion, the impact of metformin on macrophages by suppressing a HIF1α-dependent proinflammatory program is likely responsible for a secondary beneficial effect on insulin-mediated glucose uptake and β-adrenergic responses in brown adipocytes.
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Affiliation(s)
- Nuria Pescador
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain.
| | - Vera Francisco
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain
| | - Patricia Vázquez
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Eva María Esquinas
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain
| | - Cristina González-Páramos
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Departamento de Bioquímica. Facultad de Medicina. Universidad Autónoma de Madrid, Spain and Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERer), Instituto de Salud Carlos III, Madrid, Spain
| | - M Pilar Valdecantos
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Irma García-Martínez
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Andrés A Urrutia
- Research Unit, Hospital de La Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Spain
| | - Laura Ruiz
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Escalona-Garrido
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain
| | - Marc Foretz
- Université de Paris, Institut Cochin, INSERM, CNRS, F-75014, Paris, France
| | - Benoit Viollet
- Université de Paris, Institut Cochin, INSERM, CNRS, F-75014, Paris, France
| | - Miguel Ángel Fernández-Moreno
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Departamento de Bioquímica. Facultad de Medicina. Universidad Autónoma de Madrid, Spain and Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERer), Instituto de Salud Carlos III, Madrid, Spain
| | - Alfonso L Calle-Pascual
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain; Departamento de Endocrinología y Nutrición, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria Del Hospital Clínico San Carlos (IdISSC), Madrid, Spain; Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
| | - María Jesús Obregón
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain
| | - Julián Aragonés
- Research Unit, Hospital de La Princesa, Instituto Investigación Sanitaria Princesa, Universidad Autónoma de Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBERcv), Instituto de Salud Carlos III, Madrid, Spain
| | - Ángela M Valverde
- Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERdem), Instituto de Salud Carlos III, Madrid, Spain.
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Rapamycin negatively impacts insulin signaling, glucose uptake and uncoupling protein-1 in brown adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1929-1941. [PMID: 27686967 DOI: 10.1016/j.bbalip.2016.09.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/20/2016] [Accepted: 09/22/2016] [Indexed: 11/21/2022]
Abstract
New onset diabetes after transplantation (NODAT) is a metabolic disorder that affects 40% of patients on immunosuppressive agent (IA) treatment, such as rapamycin (also known as sirolimus). IAs negatively modulate insulin action in peripheral tissues including skeletal muscle, liver and white fat. However, the effects of IAs on insulin sensitivity and thermogenesis in brown adipose tissue (BAT) have not been investigated. We have analyzed the impact of rapamycin on insulin signaling, thermogenic gene-expression and mitochondrial respiration in BAT. Treatment of brown adipocytes with rapamycin for 16h significantly decreased insulin receptor substrate 1 (IRS1) protein expression and insulin-mediated protein kinase B (Akt) phosphorylation. Consequently, both insulin-induced glucose transporter 4 (GLUT4) translocation to the plasma membrane and glucose uptake were decreased. Early activation of the N-terminal Janus activated kinase (JNK) was also observed, thereby increasing IRS1 Ser 307 phosphorylation. These effects of rapamycin on insulin signaling in brown adipocytes were partly prevented by a JNK inhibitor. In vivo treatment of rats with rapamycin for three weeks abolished insulin-mediated Akt phosphorylation in BAT. Rapamycin also inhibited norepinephrine (NE)-induced lipolysis, the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and uncoupling protein (UCP)-1 in brown adipocytes. Importantly, basal mitochondrial respiration, proton leak and maximal respiratory capacity were significantly decreased in brown adipocytes treated with rapamycin. In conclusion, we demonstrate, for the first time the important role of brown adipocytes as target cells of rapamycin, suggesting that insulin resistance in BAT might play a major role in NODAT development.
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Pandey PR, Xing F, Sharma S, Watabe M, Pai SK, Iiizumi-Gairani M, Fukuda K, Hirota S, Mo YY, Watabe K. Elevated lipogenesis in epithelial stem-like cell confers survival advantage in ductal carcinoma in situ of breast cancer. Oncogene 2012. [PMID: 23208501 DOI: 10.1038/onc.2012.519] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Upregulation of lipogenesis is a hallmark of cancer and blocking the lipogenic pathway is known to cause tumor cell death by apoptosis. However, the exact role of lipogenesis in tumor initiation is as yet poorly understood. We examined the expression profile of key lipogenic genes in clinical samples of ductal carcinoma in situ (DCIS) of breast cancer and found that these genes were significantly upregulated in DCIS. We also isolated cancer stem-like cells (CSCs) from DCIS.com cell line using cell surface markers (CS24(-)CD44(+)ESA(+)) and found that this cell population has significantly higher tumor-initiating ability to generate DCIS compared with the non-stem-like population. Furthermore, the CSCs showed significantly higher level of expression of all lipogenic genes than the counterpart population from non-tumorigenic breast cancer cell line, MCF10A. Importantly, ectopic expression of SREBP1, the master regulator of lipogenic genes, in MCF10A significantly enhanced lipogenesis in stem-like cells and promoted cell growth as well as mammosphere formation. Moreover, SREBP1 expression significantly increased the ability of cell survival of CSCs from MCF10AT, another cell line that is capable of generating DCIS, in mouse and in cell culture. These results indicate that upregulation of lipogenesis is a pre-requisite for DCIS formation by endowing the ability of cell survival. We have also shown that resveratrol was capable of blocking the lipogenic gene expression in CSCs and significantly suppressed their ability to generate DCIS in animals, which provides us with a strong rationale to use this agent for chemoprevention against DCIS.
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Affiliation(s)
- P R Pandey
- Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
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Murholm M, Dixen K, Hansen JB. Ras signalling regulates differentiation and UCP1 expression in models of brown adipogenesis. Biochim Biophys Acta Gen Subj 2010; 1800:619-27. [PMID: 20307629 DOI: 10.1016/j.bbagen.2010.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 03/02/2010] [Accepted: 03/11/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND The Ras/Raf/MEK/ERK pathway has been recognised as an important signalling module in adipogenesis and adipocyte function, but whether it promotes or inhibits the formation of fat cells has not been reconciled. METHODS Here we investigate the significance of Ras signalling intensity on two unrelated models of mouse brown adipocyte differentiation. RESULTS A constitutively active H-Ras mutant (Ras V12) caused a complete block of adipose conversion, as manifested by a lack of both lipid accumulation and induction of adipocyte gene expression. The Ras V12-mediated impediment of differentiation was inefficiently rescued by forced expression of the adipogenic transcription factors C/EBPalpha and PPARgamma. However, the defective differentiation was alleviated by MEK inhibitors, suggesting that the obstruction of differentiation was dependent on activation of ERK. A dominant interfering H-Ras mutant (Ras N17) did not inhibit differentiation, but led to increased expression of genes important for energy dissipation in brown fat cells, including UCP1. GENERAL SIGNIFICANCE These data suggest that the intensity of Ras signalling is important for differentiation and UCP1 expression in models of brown adipogenesis.
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Affiliation(s)
- Maria Murholm
- Department of Biomedical Sciences, The Panum Institute, University of Copenhagen, DK-2200 Copenhagen N, Denmark
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Zhao Y, Altman BJ, Coloff JL, Herman CE, Jacobs SR, Wieman HL, Wofford JA, Dimascio LN, Ilkayeva O, Kelekar A, Reya T, Rathmell JC. Glycogen synthase kinase 3alpha and 3beta mediate a glucose-sensitive antiapoptotic signaling pathway to stabilize Mcl-1. Mol Cell Biol 2007; 27:4328-39. [PMID: 17371841 PMCID: PMC1900055 DOI: 10.1128/mcb.00153-07] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glucose uptake and utilization are growth factor-stimulated processes that are frequently upregulated in cancer cells and that correlate with enhanced cell survival. The mechanism of metabolic protection from apoptosis, however, has been unclear. Here we identify a novel signaling pathway initiated by glucose catabolism that inhibited apoptotic death of growth factor-deprived cells. We show that increased glucose metabolism protected cells against the proapoptotic Bcl-2 family protein Bim and attenuated degradation of the antiapoptotic Bcl-2 family protein Mcl-1. Maintenance of Mcl-1 was critical for this protection, as glucose metabolism failed to protect Mcl-1-deficient cells from apoptosis. Increased glucose metabolism stabilized Mcl-1 in both cell lines and primary lymphocytes via inhibitory phosphorylation of glycogen synthase kinase 3alpha and 3beta (GSK-3alpha/beta), which otherwise promoted Mcl-1 degradation. While a number of kinases can phosphorylate and inhibit GSK-3alpha/beta, we provide evidence that protein kinase C may be stimulated by glucose-induced alterations in diacylglycerol levels or distribution to phosphorylate GSK-3alpha/beta, maintain Mcl-1 levels, and inhibit cell death. These data provide a novel nutrient-sensitive mechanism linking glucose metabolism and Bcl-2 family proteins via GSK-3 that may promote survival of cells with high rates of glucose utilization, such as growth factor-stimulated or cancerous cells.
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Affiliation(s)
- Yuxing Zhao
- Department of Pharmacology and Cancer Biology, DUMC Box 3813, Durham, NC 27710, USA
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Valverde AM, Benito M, Lorenzo M. The brown adipose cell: a model for understanding the molecular mechanisms of insulin resistance. ACTA ACUST UNITED AC 2005; 183:59-73. [PMID: 15654920 DOI: 10.1111/j.1365-201x.2004.01384.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Type 2 diabetes mellitus is a complex metabolic disease that occurs when insulin secretion can no longer compensate insulin resistance in peripheral tissues. At the molecular level, insulin resistance correlates with impaired insulin signalling. This review provides new insights into the molecular mechanisms of insulin action and resistance in brown adipose tissue and pinpoints the role of this tissue in the control of glucose homeostasis. Brown adipocytes are target cells for insulin and IGF-I action, especially during late foetal development when insulin supports survival and promotes both adipogenic and thermogenic differentiation. The main pathway involved in insulin induction of adipogenic differentiation, monitored by fatty acid synthase expression, is the cascade insulin receptor substrate (IRS)-1/phosphatidylinositol 3-kinase (PI3K)/Akt. Glucose transport in these cells is maintained mainly by the activity of GLUT4. Acute insulin treatment stimulates glucose transport largely by mediating translocation of GLUT4 to the plasma membrane, involving the activation of IRS-2/PI3K, and the downstream targets Akt and protein kinase C zeta. Tumour necrosis factor (TNF-alpha) caused insulin resistance on glucose uptake by impairing insulin signalling at the level of IRS-2. Activation of stress kinases and phosphatases by this cytokine contribute to insulin resistance. Furthermore, brown adipocytes are also target cells for rosiglitazone action since they show a high expression of peroxisome proliferator activated receptor gamma, and rosiglitazone increased the expression of the thermogenic uncoupling protein 1. Rosiglitazone ameliorates insulin resistance provoked by TNF-alpha, completely restoring insulin-stimulated glucose uptake in parallel to the insulin signalling cascade. Accordingly, foetal brown adipocytes represent a model for investigating insulin action, as well as for the mechanism by which rosiglitazone increase insulin sensitivity under situations that mimic insulin resistance.
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Affiliation(s)
- A M Valverde
- Instituto de Bioquimica. Centro Mixto CSIC/UCM, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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Abstract
The function of brown adipose tissue is to transfer energy from food into heat; physiologically, both the heat produced and the resulting decrease in metabolic efficiency can be of significance. Both the acute activity of the tissue, i.e., the heat production, and the recruitment process in the tissue (that results in a higher thermogenic capacity) are under the control of norepinephrine released from sympathetic nerves. In thermoregulatory thermogenesis, brown adipose tissue is essential for classical nonshivering thermogenesis (this phenomenon does not exist in the absence of functional brown adipose tissue), as well as for the cold acclimation-recruited norepinephrine-induced thermogenesis. Heat production from brown adipose tissue is activated whenever the organism is in need of extra heat, e.g., postnatally, during entry into a febrile state, and during arousal from hibernation, and the rate of thermogenesis is centrally controlled via a pathway initiated in the hypothalamus. Feeding as such also results in activation of brown adipose tissue; a series of diets, apparently all characterized by being low in protein, result in a leptin-dependent recruitment of the tissue; this metaboloregulatory thermogenesis is also under hypothalamic control. When the tissue is active, high amounts of lipids and glucose are combusted in the tissue. The development of brown adipose tissue with its characteristic protein, uncoupling protein-1 (UCP1), was probably determinative for the evolutionary success of mammals, as its thermogenesis enhances neonatal survival and allows for active life even in cold surroundings.
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Affiliation(s)
- Barbara Cannon
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, Stockholm, Sweden
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Navarro P, Valverde AM, Benito M, Lorenzo M. Activated Ha-ras induces apoptosis by association with phosphorylated Bcl-2 in a mitogen-activated protein kinase-independent manner. J Biol Chem 1999; 274:18857-63. [PMID: 10383381 DOI: 10.1074/jbc.274.27.18857] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Serum deprivation of Ha-ras-transformed brown adipocyte cell line resulted in a dramatic apoptotic cell death, as detected either by DNA laddering or by an increase in the percentage of hypodiploid cells or by nuclei condensation and fragmentation, as compared with immortalized cell line or primary fetal brown adipocytes. Moreover, transient transfection of immortalized brown adipocytes with a constitutively active ras gene (Ha-raslys12) mimics the high rate of apoptosis detected in the transformed cell line. On the other hand, transient transfection of the dominant-negative construct of raf-1 rescued serum-deprived Ha-ras-transformed brown adipocytes from apoptosis, decreasing the percentage of hypodiploid cells, the external display of phosphatidylserine, and the DNA laddering. However, inhibition of mitogen-activated protein kinase with PD098059 did not preclude apoptosis and in fact increased the rate of apoptosis observed in serum-deprived Ha-ras-transformed cells, indicating that the Ras/Raf-1 pathway induced apoptosis throughout a mitogen-activated protein kinase kinase 1 (MEK-1)-independent pathway. Furthermore, apoptosis in Ha-ras-transformed brown adipocytes is concurrent with an up-regulation in the expression of the pro-apoptotic protein Bcl-xS, the expression of the anti-apoptotic protein Bcl-2 being down-regulated. Finally, an association of Ras and Raf with phosphorylated Bcl-2 protein was demonstrated in immunoprecipitates from apoptotic cells. Thus, we propose a mechanism of apoptosis in Ha-ras-transformed adipocytes under serum deprivation involving Raf-1 association with phosphorylated Bcl-2, down-regulation of Bcl-2 expression, and up-regulation of Bcl-xS expression.
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Affiliation(s)
- P Navarro
- Departamento de Bioquimica y Biologia Molecular II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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