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Antagonistic effect of atorvastatin on high fat diet induced survival during acute Chagas disease. Microbes Infect 2016; 18:675-686. [PMID: 27416748 DOI: 10.1016/j.micinf.2016.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 06/24/2016] [Accepted: 06/27/2016] [Indexed: 10/21/2022]
Abstract
Chagasic cardiomyopathy, which is seen in Chagas disease, is the most severe and life-threatening manifestation of infection by the kinetoplastid Trypanosoma cruzi. Adipose tissue and diet play a major role in maintaining lipid homeostasis and regulating cardiac pathogenesis during the development of Chagas cardiomyopathy. We have previously reported that T. cruzi has a high affinity for lipoproteins and that the invasion rate of this parasite increases in the presence of cholesterol, suggesting that drugs that inhibit cholesterol synthesis, such as statins, could affect infection and the development of Chagasic cardiomyopathy. The dual epidemic of diabetes and obesity in Latin America, the endemic regions for Chagas disease, has led to many patients in the endemic region of infection having hyperlipidemia that is being treated with statins such as atorvastatin. The current study was performed to examine mice fed on either regular or high fat diet for effects of atorvastatin on T. cruzi infection-induced myocarditis and to evaluate the effect of this treatment during infection on adipose tissue physiology and cardiac pathology. Atorvastatin was found to regulate lipolysis and cardiac lipidopathy during acute T. cruzi infection in mice and to enhance tissue parasite load, cardiac LDL levels, inflammation, and mortality in during acute infection. Overall, these data suggest that statins, such as atorvastatin, have deleterious effects during acute Chagas disease.
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102
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Ikonomov OC, Sbrissa D, Delvecchio K, Rillema JA, Shisheva A. Unexpected severe consequences of Pikfyve deletion by aP2- or Aq-promoter-driven Cre expression for glucose homeostasis and mammary gland development. Physiol Rep 2016; 4:4/11/e12812. [PMID: 27273882 PMCID: PMC4908490 DOI: 10.14814/phy2.12812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 05/04/2016] [Indexed: 01/03/2023] Open
Abstract
Systemic deficiency of PIKfyve, the evolutionarily conserved phosphoinositide kinase synthesizing cellular PtdIns5P and PtdIns(3,5)P2 and implicated in insulin signaling, causes early embryonic death in mice. In contrast, mice with muscle‐specific Pikfyve disruption have normal lifespan but exhibit early‐age whole‐body glucose intolerance and muscle insulin resistance, thus establishing the key role of muscle PIKfyve in glucose homeostasis. Fat and muscle tissues control postprandial glucose clearance through different mechanisms, raising questions as to whether adipose Pikfyve disruption will also trigger whole‐body metabolic abnormalities, and if so, what the mechanism might be. To clarify these issues, here we have characterized two new mouse models with adipose tissue disruption of Pikfyve through Cre recombinase expression driven by adipose‐specific aP2‐ or adiponectin (Aq) promoters. Whereas both mouse lines were ostensibly normal until adulthood, their glucose homeostasis and systemic insulin sensitivity were severely dysregulated. These abnormalities stemmed in part from accelerated fat‐cell lipolysis and elevated serum FFA. Intriguingly, aP2‐Cre‐PIKfyvefl/fl but not Aq‐Cre‐PIKfyvefl/fl females had severely impaired pregnancy‐induced mammary gland differentiation and lactogenesis, consistent with aP2‐Cre‐mediated Pikfyve excision in nonadipogenic tissues underlying this defect. Intriguingly, whereas mammary glands from postpartum control and Aq‐Cre‐PIKfyvefl/fl mice or ex vivo mammary gland explants showed profound upregulation of PIKfyve protein levels subsequent to prolactin receptor activation, such increases were not apparent in aP2‐Cre‐PIKfyvefl/fl females. Collectively, our data identify for the first time that adipose tissue Pikfyve plays a key role in the mechanisms regulating glucose homeostasis and that the PIKfyve pathway is critical in mammary epithelial differentiation during pregnancy and lactogenesis downstream of prolactin receptor signaling.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Khortnal Delvecchio
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - James A Rillema
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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103
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Regulation of Lipolysis and Adipose Tissue Signaling during Acute Endotoxin-Induced Inflammation: A Human Randomized Crossover Trial. PLoS One 2016; 11:e0162167. [PMID: 27627109 PMCID: PMC5023116 DOI: 10.1371/journal.pone.0162167] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 08/17/2016] [Indexed: 01/19/2023] Open
Abstract
Background Lipolysis is accelerated during the acute phase of inflammation, a process being regulated by pro-inflammatory cytokines (e.g. TNF-α), stress-hormones, and insulin. The intracellular mechanisms remain elusive and we therefore measured pro- and anti-lipolytic signaling pathways in adipocytes after in vivo endotoxin exposure. Methods Eight healthy, lean, male subjects were investigated using a randomized cross over trial with two interventions: i) bolus injection of saline (Placebo) and ii) bolus injection of lipopolysaccharide endotoxin (LPS). A 3H-palmitate tracer was used to measure palmitate rate of appearance (Rapalmitate) and indirect calorimetry was performed to measure energy expenditures and lipid oxidation rates. A subcutaneous abdominal fat biopsy was obtained during both interventions and subjected to western blotting and qPCR quantifications. Results LPS caused a mean increase in serum free fatty acids (FFA) concentrations of 90% (CI-95%: 37–142, p = 0.005), a median increase in Rapalmitate of 117% (CI-95%: 77–166, p<0.001), a mean increase in lipid oxidation of 49% (CI-95%: 1–96, p = 0.047), and a median increase in energy expenditure of 28% (CI-95%: 16–42, p = 0.001) compared with Placebo. These effects were associated with increased phosphorylation of hormone sensitive lipase (pHSL) at ser650 in adipose tissue (p = 0.03), a trend towards elevated pHSL at ser552 (p = 0.09) and cAMP-dependent protein kinase A (PKA) phosphorylation of perilipin 1 (PLIN1) (p = 0.09). Phosphatase and tensin homolog (PTEN) also tended to increase (p = 0.08) while phosphorylation of Akt at Thr308 tended to decrease (p = 0.09) during LPS compared with Placebo. There was no difference between protein or mRNA expression of ATGL, G0S2, and CGI-58. Conclusion LPS stimulated lipolysis in adipose tissue and is associated with increased pHSL and signs of increased PLIN1 phosphorylation combined with a trend toward decreased insulin signaling. The combination of these mechanisms appear to be the driving forces behind the increased lipolysis observed in the early stages of acute inflammation and sepsis. Trial Registration ClinicalTrials.gov NCT01705782
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104
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Li T, Mo H, Chen W, Li L, Xiao Y, Zhang J, Li X, Lu Y. Role of the PI3K-Akt Signaling Pathway in the Pathogenesis of Polycystic Ovary Syndrome. Reprod Sci 2016; 24:646-655. [PMID: 27613818 DOI: 10.1177/1933719116667606] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This review aimed to focus on the recent progress of the understanding of the role of phosphatidylinositol 3-kinase (PI3K) in polycystic ovary syndrome (PCOS). In recent years, it has been increasingly recognized that PI3K plays an important role in PCOS whose pathogenesis is unclear. However, research continues into revealing the details of how PI3Ks are involved in developing PCOS. Previous studies have shown that activation of the PI3K-protein kinase B (Akt) signaling pathway has important effects on insulin resistance and endometrial cancer. Knowledge of the action of PI3K in PCOS might provide valuable information to further validate the pathogenesis of PCOS and suggest new methods of treatment.
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Affiliation(s)
- Tiantian Li
- 1 Department of Obstetrics and Gynecology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, China
| | - Hui Mo
- 2 Laboratory of Chinese Medicine Quality Research, Macau University of Science and Technology, Macau, China
| | - Wenfeng Chen
- 1 Department of Obstetrics and Gynecology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, China
| | - Li Li
- 1 Department of Obstetrics and Gynecology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, China.,2 Laboratory of Chinese Medicine Quality Research, Macau University of Science and Technology, Macau, China
| | - Yao Xiao
- 2 Laboratory of Chinese Medicine Quality Research, Macau University of Science and Technology, Macau, China
| | - Jing Zhang
- 3 Guangzhou Family Planning Specialty Hospital, Guangzhou, China
| | - Xiaofang Li
- 1 Department of Obstetrics and Gynecology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, China
| | - Ying Lu
- 1 Department of Obstetrics and Gynecology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, China
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105
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CREBH-FGF21 axis improves hepatic steatosis by suppressing adipose tissue lipolysis. Sci Rep 2016; 6:27938. [PMID: 27301791 PMCID: PMC4908383 DOI: 10.1038/srep27938] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/26/2016] [Indexed: 02/07/2023] Open
Abstract
Adipose tissue lipolysis produces glycerol and nonesterified fatty acids (NEFA) that serve as energy sources during nutrient scarcity. Adipose tissue lipolysis is tightly regulated and excessive lipolysis causes hepatic steatosis, as NEFA released from adipose tissue constitutes a major source of TG in the liver of patients with nonalcoholic fatty liver diseases. Here we show that the liver-enriched transcription factor CREBH is activated by TG accumulation and induces FGF21, which suppresses adipose tissue lipolysis, ameliorating hepatic steatosis. CREBH-deficient mice developed severe hepatic steatosis due to increased adipose tissue lipolysis, when fasted or fed a high-fat low-carbohydrate ketogenic diet. FGF21 production was impaired in CREBH-deficient mice, and adenoviral overexpression of FGF21 suppressed adipose tissue lipolysis and improved hepatic steatosis in these mice. Thus, our results uncover a negative feedback loop in which CREBH regulates NEFA flux from adipose tissue to the liver via FGF21.
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106
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Abstract
Angiopoietin-like protein 3 (ANGPTL3) is a secretory protein regulating plasma lipid levels via affecting lipoprotein lipase- and endothelial lipase-mediated hydrolysis of triglycerides and phospholipids. ANGPTL3-deficiency due to loss-of-function mutations in the ANGPTL3 gene causes familial combined hypobetalipoproteinemia (FHBL2, OMIM # 605019), a phenotype characterized by low concentration of all major lipoprotein classes in circulation. ANGPTL3 is therefore a potential therapeutic target to treat combined hyperlipidemia, a major risk factor for atherosclerotic coronary heart disease. This review focuses on the mechanisms behind ANGPTL3-deficiency induced FHBL2.
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Affiliation(s)
- Anna Tikka
- National Institute for Health and Welfare. Genomics and Biomarkers Unit, Biomedicum, Haartmaninkatu 8, 00250, Helsinki, Finland.
| | - Matti Jauhiainen
- National Institute for Health and Welfare. Genomics and Biomarkers Unit, Biomedicum, Haartmaninkatu 8, 00250, Helsinki, Finland
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107
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Huttala O, Mysore R, Sarkanen JR, Heinonen T, Olkkonen VM, Ylikomi T. Differentiation of human adipose stromal cells in vitro into insulin-sensitive adipocytes. Cell Tissue Res 2016; 366:63-74. [DOI: 10.1007/s00441-016-2409-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/05/2016] [Indexed: 12/28/2022]
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108
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Anti-hyperlipidemic and anti-peroxidative role of pterostilbene via Nrf2 signaling in experimental diabetes. Eur J Pharmacol 2016; 777:9-16. [DOI: 10.1016/j.ejphar.2016.02.054] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/19/2016] [Accepted: 02/23/2016] [Indexed: 12/25/2022]
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109
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Lee JTH, Huang Z, Pan K, Zhang HJ, Woo CW, Xu A, Wong CM. Adipose-derived lipocalin 14 alleviates hyperglycaemia by suppressing both adipocyte glycerol efflux and hepatic gluconeogenesis in mice. Diabetologia 2016; 59:604-13. [PMID: 26592241 DOI: 10.1007/s00125-015-3813-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 10/23/2015] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS Growing evidence supports that dysregulation of adipose tissue-derived factors contributes to the pathogenesis of diabetes and its complications. Since our global gene profiling analysis has identified lipocalin-14 (LCN14)-a secretory protein with lipid-binding properties-as a potential adipokine highly expressed in white adipose tissue (WAT), this study aims to explore the metabolic roles of LCN14 in obese mice, and to investigate the functional mechanisms involved. METHODS Immunoassays and western blotting were performed to determine the circulating level and tissue distribution of LCN14, respectively. Recombinant adeno-associated virus (rAAV)-mediated gene delivery was used to overexpress LCN14 in diet-induced obese (DIO) mice and the effects on glucose and lipid metabolism were examined. RESULTS LCN14 is expressed predominantly in WAT. Both circulating levels of LCN14 and its expression in adipose tissues are repressed in DIO and genetically inherited diabetic (db/db) mice. Overexpression of LCN14 by rAAV-mediated gene delivery in DIO mice significantly increased insulin sensitivity in major metabolic tissues and ameliorated hyperglycaemia by inhibiting hepatic gluconeogenesis. The reduced hepatic glucose production is attributed to the suppressive effects of LCN14 on the expression of gluconeogenic genes and on glycerol efflux in adipocytes, possibly by reducing the expression of aquaporin-7. CONCLUSIONS/INTERPRETATION Reduced LCN14 expression is involved in the pathogenesis of obesity-related metabolic dysregulation. LCN14 exerts its beneficial effects on glucose homeostasis and insulin sensitivity via its actions in both adipocytes and hepatocytes.
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Affiliation(s)
- Jimmy Tsz Hang Lee
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
| | - Zhe Huang
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
| | - Kewu Pan
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
| | - Herbert Jialiang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
| | - Connie Waihong Woo
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
- Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China
| | - Chi-Ming Wong
- State Key Laboratory of Pharmaceutical Biotechnology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China.
- Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China.
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China.
- Research Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China.
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110
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Takahashi Y, Shinoda A, Kamada H, Shimizu M, Inoue J, Sato R. Perilipin2 plays a positive role in adipocytes during lipolysis by escaping proteasomal degradation. Sci Rep 2016; 6:20975. [PMID: 26876687 PMCID: PMC4753471 DOI: 10.1038/srep20975] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 01/14/2016] [Indexed: 12/18/2022] Open
Abstract
Perilipin2 (Plin2), also known as adipose differentiation-related protein (ADRP), or adipophilin, is a member of the PAT family involved in lipid droplet (LD) formation in the liver and peripheral tissues. Although Plin2 was originally identified as a highly expressed gene in adipocytes, its physiological role in mature adipocytes is largely unknown. In this report, we investigated the regulation of Plin2 expression and its function in differentiated adipocytes of mouse embryonic fibroblasts (MEFs). Plin2 mRNA levels increased during adipocyte differentiation whereas protein levels did not. Plin2 was degraded through the ubiquitin-proteasome pathway but was inhibited by lipolytic inducers. Furthermore, lentiviral-mediated Plin2 knockdown attenuated lipolysis in differentiated MEFs in a time-dependent manner. Oleic acid-induced LD formation enhanced Plin2 protein stability when it was localized to LDs. Furthermore, a mutational analysis revealed that the ubiquitination and degradation of Plin2 required both the second and third alanine in the N-terminal region. These results suggest that Plin2 is degraded in the cytosol in its N-terminal amino acid sequence-dependent manner and instead becomes stable when localized on LDs. Our findings highlight the relationship between protein stability and a previously unnoticed function of Plin2 during lipolysis in adipocytes.
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Affiliation(s)
- Yu Takahashi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Akihiro Shinoda
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Haruhiko Kamada
- Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, Osaka, Japan.,The Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan
| | - Makoto Shimizu
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Jun Inoue
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuichiro Sato
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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111
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Baeza-Raja B, Sachs BD, Li P, Christian F, Vagena E, Davalos D, Le Moan N, Ryu JK, Sikorski SL, Chan JP, Scadeng M, Taylor SS, Houslay MD, Baillie GS, Saltiel AR, Olefsky JM, Akassoglou K. p75 Neurotrophin Receptor Regulates Energy Balance in Obesity. Cell Rep 2015; 14:255-68. [PMID: 26748707 DOI: 10.1016/j.celrep.2015.12.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 08/05/2015] [Accepted: 12/02/2015] [Indexed: 02/06/2023] Open
Abstract
Obesity and metabolic syndrome reflect the dysregulation of molecular pathways that control energy homeostasis. Here, we show that the p75 neurotrophin receptor (p75(NTR)) controls energy expenditure in obese mice on a high-fat diet (HFD). Despite no changes in food intake, p75(NTR)-null mice were protected from HFD-induced obesity and remained lean as a result of increased energy expenditure without developing insulin resistance or liver steatosis. p75(NTR) directly interacts with the catalytic subunit of protein kinase A (PKA) and regulates cAMP signaling in adipocytes, leading to decreased lipolysis and thermogenesis. Adipocyte-specific depletion of p75(NTR) or transplantation of p75(NTR)-null white adipose tissue (WAT) into wild-type mice fed a HFD protected against weight gain and insulin resistance. Our results reveal that signaling from p75(NTR) to cAMP/PKA regulates energy balance and suggest that non-CNS neurotrophin receptor signaling could be a target for treating obesity and the metabolic syndrome.
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Affiliation(s)
- Bernat Baeza-Raja
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Benjamin D Sachs
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Pingping Li
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Frank Christian
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Eirini Vagena
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Dimitrios Davalos
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Natacha Le Moan
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jae Kyu Ryu
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shoana L Sikorski
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Justin P Chan
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Miriam Scadeng
- Department of Radiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan S Taylor
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA; Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Miles D Houslay
- Institute of Pharmaceutical Science, King's College London, London SE1 9NH, UK
| | - George S Baillie
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Alan R Saltiel
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jerrold M Olefsky
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Katerina Akassoglou
- Gladstone Institute of Neurological Disease, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
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112
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Abbondante S, Eckel-Mahan KL, Ceglia NJ, Baldi P, Sassone-Corsi P. Comparative Circadian Metabolomics Reveal Differential Effects of Nutritional Challenge in the Serum and Liver. J Biol Chem 2015; 291:2812-28. [PMID: 26644470 DOI: 10.1074/jbc.m115.681130] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Indexed: 01/07/2023] Open
Abstract
Diagnosis and therapeutic interventions in pathological conditions rely upon clinical monitoring of key metabolites in the serum. Recent studies show that a wide range of metabolic pathways are controlled by circadian rhythms whose oscillation is affected by nutritional challenges, underscoring the importance of assessing a temporal window for clinical testing and thereby questioning the accuracy of the reading of critical pathological markers in circulation. We have been interested in studying the communication between peripheral tissues under metabolic homeostasis perturbation. Here we present a comparative circadian metabolomic analysis on serum and liver in mice under high fat diet. Our data reveal that the nutritional challenge induces a loss of serum metabolite rhythmicity compared with liver, indicating a circadian misalignment between the tissues analyzed. Importantly, our results show that the levels of serum metabolites do not reflect the circadian liver metabolic signature or the effect of nutritional challenge. This notion reveals the possibility that misleading reads of metabolites in circulation may result in misdiagnosis and improper treatments. Our findings also demonstrate a tissue-specific and time-dependent disruption of metabolic homeostasis in response to altered nutrition.
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Affiliation(s)
- Serena Abbondante
- From the Center for Epigenetics and Metabolism, U904 INSERM, and the Department of Biological Chemistry, University of California, Irvine, California 92697-4625 and
| | - Kristin L Eckel-Mahan
- From the Center for Epigenetics and Metabolism, U904 INSERM, and the Department of Biological Chemistry, University of California, Irvine, California 92697-4625 and
| | - Nicholas J Ceglia
- the Department of Biological Chemistry, University of California, Irvine, California 92697-4625 and the Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, California 92697-3435
| | - Pierre Baldi
- the Department of Biological Chemistry, University of California, Irvine, California 92697-4625 and the Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California, Irvine, California 92697-3435
| | - Paolo Sassone-Corsi
- From the Center for Epigenetics and Metabolism, U904 INSERM, and the Department of Biological Chemistry, University of California, Irvine, California 92697-4625 and
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113
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Tsiloulis T, Watt MJ. Exercise and the Regulation of Adipose Tissue Metabolism. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 135:175-201. [PMID: 26477915 DOI: 10.1016/bs.pmbts.2015.06.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Adipose tissue is a major regulator of metabolism in health and disease. The prominent roles of adipose tissue are to sequester fatty acids in times of energy excess and to release fatty acids via the process of lipolysis during times of high-energy demand, such as exercise. The fatty acids released during lipolysis are utilized by skeletal muscle to produce adenosine triphosphate to prevent fatigue during prolonged exercise. Lipolysis is controlled by a complex interplay between neuro-humoral regulators, intracellular signaling networks, phosphorylation events involving protein kinase A, translocation of proteins within the cell, and protein-protein interactions. Herein, we describe in detail the cellular and molecular regulation of lipolysis and how these processes are altered by acute exercise. We also explore the processes that underpin adipocyte adaptation to endurance exercise training, with particular focus on epigenetic modifications, control by microRNAs and mitochondrial adaptations. Finally, we examine recent literature describing how exercise might influence the conversion of traditional white adipose tissue to high energy-consuming "brown-like" adipocytes and the implications that this has on whole-body energy balance.
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Affiliation(s)
- Thomas Tsiloulis
- Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Matthew J Watt
- Biology of Lipid Metabolism Laboratory, Department of Physiology, Monash University, Clayton, Victoria, Australia.
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Tessier SN, Zhang J, Biggar KK, Wu CW, Pifferi F, Perret M, Storey KB. Regulation of the PI3K/AKT Pathway and Fuel Utilization During Primate Torpor in the Gray Mouse Lemur, Microcebus murinus. GENOMICS PROTEOMICS & BIOINFORMATICS 2015; 13:91-102. [PMID: 26092184 PMCID: PMC4511781 DOI: 10.1016/j.gpb.2015.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 03/23/2015] [Indexed: 12/19/2022]
Abstract
Gray mouse lemurs (Microcebus murinus) from Madagascar present an excellent model for studies of torpor regulation in a primate species. In the present study, we analyzed the response of the insulin signaling pathway as well as controls on carbohydrate sparing in six different tissues of torpid versus aroused gray mouse lemurs. We found that the relative level of phospho-insulin receptor substrate (IRS-1) was significantly increased in muscle, whereas the level of phospho-insulin receptor (IR) was decreased in white adipose tissue (WAT) of torpid animals, both suggesting an inhibition of insulin/insulin-like growth factor-1 (IGF-1) signaling during torpor in these tissues. By contrast, the level of phospho-IR was increased in the liver. Interestingly, muscle, WAT, and liver occupy central roles in whole body homeostasis and each displays regulatory controls operating at the plasma membrane. Changes in other tissues included an increase in phospho-glycogen synthase kinase 3α (GSK3α) and decrease in phospho-ribosomal protein S6 (RPS6) in the heart, and a decrease in phospho-mammalian target of rapamycin (mTOR) in the kidney. Pyruvate dehydrogenase (PDH) that gates carbohydrate entry into mitochondria is inhibited via phosphorylation by pyruvate dehydrogenase kinase (e.g., PDK4). In the skeletal muscle, the protein expression of PDK4 and phosphorylated PDH at Ser 300 was increased, suggesting inhibition during torpor. In contrast, there were no changes in levels of PDH expression and phosphorylation in other tissues comparing torpid and aroused animals. Information gained from these studies highlight the molecular controls that help to regulate metabolic rate depression and balance energetics during primate torpor.
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Affiliation(s)
- Shannon N Tessier
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Department of Surgery & Center for Engineering in Medicine, Massachusetts General Hospital & Harvard Medical School, Charlestown, MA 02129, USA
| | - Jing Zhang
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Chemistry and Chemical Engineering Department, Royal Military College of Canada, Kingston, ON K7K 7B4, Canada
| | - Kyle K Biggar
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Biochemistry Department, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
| | - Cheng-Wei Wu
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; Department of Biology, Genetics Institute, University of Florida, Gainesville, FL 32611, USA
| | - Fabien Pifferi
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, Brunoy 91800, France
| | - Martine Perret
- UMR 7179 Centre National de la Recherche Scientifique, Muséum National d'Histoire Naturelle, Brunoy 91800, France
| | - Kenneth B Storey
- Institute of Biochemistry & Department of Biology, Carleton University, Ottawa, ON K1S 5B6, Canada.
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115
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The Role of PDE3B Phosphorylation in the Inhibition of Lipolysis by Insulin. Mol Cell Biol 2015; 35:2752-60. [PMID: 26031333 DOI: 10.1128/mcb.00422-15] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 05/26/2015] [Indexed: 11/20/2022] Open
Abstract
Inhibition of adipocyte lipolysis by insulin is important for whole-body energy homeostasis; its disruption has been implicated as contributing to the development of insulin resistance and type 2 diabetes mellitus. The main target of the antilipolytic action of insulin is believed to be phosphodiesterase 3B (PDE3B), whose phosphorylation by Akt leads to accelerated degradation of the prolipolytic second messenger cyclic AMP (cAMP). To test this hypothesis genetically, brown adipocytes lacking PDE3B were examined for their regulation of lipolysis. In Pde3b knockout (KO) adipocytes, insulin was unable to suppress β-adrenergic receptor-stimulated glycerol release. Reexpressing wild-type PDE3B in KO adipocytes fully rescued the action of insulin against lipolysis. Surprisingly, a mutant form of PDE3B that ablates the major Akt phosphorylation site, murine S273, also restored the ability of insulin to suppress lipolysis. Taken together, these data suggest that phosphorylation of PDE3B by Akt is not required for insulin to suppress adipocyte lipolysis.
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116
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Koren S, DiPilato LM, Emmett MJ, Shearin AL, Chu Q, Monks B, Birnbaum MJ. The role of mouse Akt2 in insulin-dependent suppression of adipocyte lipolysis in vivo. Diabetologia 2015; 58:1063-70. [PMID: 25740694 PMCID: PMC4393789 DOI: 10.1007/s00125-015-3532-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 01/22/2015] [Indexed: 11/25/2022]
Abstract
AIM/HYPOTHESIS The release of fatty acids from adipocytes, i.e. lipolysis, is maintained under tight control, primarily by the opposing actions of catecholamines and insulin. A widely accepted model is that insulin antagonises catecholamine-dependent lipolysis through phosphorylation and activation of cAMP phosphodiesterase 3B (PDE3B) by the serine-threonine protein kinase Akt (protein kinase B). Recently, this hypothesis has been challenged, as in cultured adipocytes insulin appears, under some conditions, to suppress lipolysis independently of Akt. METHODS To address the requirement for Akt2, the predominant isoform expressed in classic insulin target tissues, in the suppression of fatty acid release in vivo, we assessed lipolysis in mice lacking Akt2. RESULTS In the fed state and following an oral glucose challenge, Akt2 null mice were glucose intolerant and hyperinsulinaemic, but nonetheless exhibited normal serum NEFA and glycerol levels, suggestive of normal suppression of lipolysis. Furthermore, insulin partially inhibited lipolysis in Akt2 null mice during an insulin tolerance test (ITT) and hyperinsulinaemic-euglycaemic clamp, respectively. In support of these in vivo observations, insulin antagonised catecholamine-induced lipolysis in primary brown fat adipocytes from Akt2-deficient mice. CONCLUSIONS/INTERPRETATION These data suggest that suppression of lipolysis by insulin in hyperinsulinaemic states can take place in the absence of Akt2.
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Affiliation(s)
- Shlomit Koren
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa M. DiPilato
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Matthew J. Emmett
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Abigail L. Shearin
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Qingwei Chu
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Bob Monks
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Morris J. Birnbaum
- The Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
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117
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Abstract
Adipose tissue is a complex, multicellular organ that profoundly influences the function of nearly all other organ systems through its diverse metabolite and adipokine secretome. Adipocytes are the primary cell type of adipose tissue and play a key role in maintaining energy homeostasis. The efficiency with which adipose tissue responds to whole-body energetic demands reflects the ability of adipocytes to adapt to an altered nutrient environment, and has profound systemic implications. Deciphering adipocyte cell biology is an important component of understanding how the aberrant physiology of expanding adipose tissue contributes to the metabolic dysregulation associated with obesity.
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Affiliation(s)
- Joseph M Rutkowski
- Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jennifer H Stern
- Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Philipp E Scherer
- Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390 Touchstone Diabetes Center, Department of Internal Medicine, and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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118
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Wu Y, Song P, Zhang W, Liu J, Dai X, Liu Z, Lu Q, Ouyang C, Xie Z, Zhao Z, Zhuo X, Viollet B, Foretz M, Wu J, Yuan Z, Zou MH. Activation of AMPKα2 in adipocytes is essential for nicotine-induced insulin resistance in vivo. Nat Med 2015; 21:373-82. [PMID: 25799226 PMCID: PMC4390501 DOI: 10.1038/nm.3826] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/17/2015] [Indexed: 12/15/2022]
Abstract
Cigarette smoking promotes body weight reduction in humans while paradoxically also promoting insulin resistance (IR) and hyperinsulinemia. However, the mechanisms behind these effects are unclear. Here we show that nicotine, a major constituent of cigarette smoke, selectively activates AMP-activated protein kinase α2 (AMPKα2) in adipocytes, which in turn phosphorylates MAP kinase phosphatase-1 (MKP1) at serine 334, initiating its proteasome-dependent degradation. The nicotine-dependent reduction of MKP1 induces the aberrant activation of both p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, leading to increased phosphorylation of insulin receptor substrate 1 (IRS1) at serine 307. Phosphorylation of IRS1 leads to its degradation, protein kinase B inhibition, and the loss of insulin-mediated inhibition of lipolysis. Consequently, nicotine increases lipolysis, which results in body weight reduction, but this increase also elevates the levels of circulating free fatty acids and thus causes IR in insulin-sensitive tissues. These results establish AMPKα2 as an essential mediator of nicotine-induced whole-body IR in spite of reductions in adiposity.
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Affiliation(s)
- Yue Wu
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ping Song
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Wencheng Zhang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Junhui Liu
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Xiaoyan Dai
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zhaoyu Liu
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Qiulun Lu
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Changhan Ouyang
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Zhonglin Xie
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Zhengxing Zhao
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Xiaozhen Zhuo
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Benoit Viollet
- 1] INSERM, U1016, Institut Cochin, Paris, France. [2] CNRS, UMR 8104, Paris, France. [3] Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marc Foretz
- 1] INSERM, U1016, Institut Cochin, Paris, France. [2] CNRS, UMR 8104, Paris, France. [3] Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Jiliang Wu
- Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Zuyi Yuan
- Department of Cardiology, Cardiovascular Research Center, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Ming-Hui Zou
- 1] Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA. [2] Key Laboratory of Hubei Province on Cardio-Cerebral Diseases, Hubei University of Science and Technology, Xianning, Hubei, China
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119
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Alinejad B, Shafiee-Nick R, Ghorbani A, Sadeghian H. MC2, a new phosphodiesterase-3 inhibitor with antilipolytic and hypolipidemic effects in normal and diabetic rats. Int J Diabetes Dev Ctries 2015. [DOI: 10.1007/s13410-015-0291-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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120
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Tan SX, Fisher-Wellman KH, Fazakerley DJ, Ng Y, Pant H, Li J, Meoli CC, Coster ACF, Stöckli J, James DE. Selective insulin resistance in adipocytes. J Biol Chem 2015; 290:11337-48. [PMID: 25720492 DOI: 10.1074/jbc.m114.623686] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Indexed: 12/14/2022] Open
Abstract
Aside from glucose metabolism, insulin regulates a variety of pathways in peripheral tissues. Under insulin-resistant conditions, it is well known that insulin-stimulated glucose uptake is impaired, and many studies attribute this to a defect in Akt signaling. Here we make use of several insulin resistance models, including insulin-resistant 3T3-L1 adipocytes and fat explants prepared from high fat-fed C57BL/6J and ob/ob mice, to comprehensively distinguish defective from unaffected aspects of insulin signaling and its downstream consequences in adipocytes. Defective regulation of glucose uptake was observed in all models of insulin resistance, whereas other major actions of insulin such as protein synthesis and anti-lipolysis were normal. This defect corresponded to a reduction in the maximum response to insulin. The pattern of change observed for phosphorylation in the Akt pathway was inconsistent with a simple defect at the level of Akt. The only Akt substrate that showed consistently reduced phosphorylation was the RabGAP AS160 that regulates GLUT4 translocation. We conclude that insulin resistance in adipose tissue is highly selective for glucose metabolism and likely involves a defect in one of the components regulating GLUT4 translocation to the cell surface in response to insulin.
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Affiliation(s)
- Shi-Xiong Tan
- From the Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia
| | - Kelsey H Fisher-Wellman
- From the Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia
| | | | - Yvonne Ng
- From the Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia
| | - Himani Pant
- From the Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia
| | - Jia Li
- From the Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia
| | - Christopher C Meoli
- From the Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales 2010, Australia, the Charles Perkins Centre, School of Molecular Biosciences and
| | - Adelle C F Coster
- the School of Mathematics and Statistics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | | | - David E James
- the Charles Perkins Centre, School of Molecular Biosciences and the School of Medicine, University of Sydney, New South Wales 2006, Australia, and
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121
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Mulumba M, Granata R, Marleau S, Ong H. QRFP-43 inhibits lipolysis by preventing ligand-induced complex formation between perilipin A, caveolin-1, the catalytic subunit of protein kinase and hormone-sensitive lipase in 3T3-L1 adipocytes. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:657-66. [PMID: 25677823 DOI: 10.1016/j.bbalip.2015.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 01/21/2015] [Accepted: 02/02/2015] [Indexed: 11/30/2022]
Abstract
QRFP (RFamide) peptides are neuropeptides involved in food intake and adiposity regulation in rodents. We have previously shown that QRFP-43 (43RFa) and QRFP-26 (26RFa) inhibited isoproterenol (ISO)-induced lipolysis in adipocytes. However, the antilipolytic signaling pathways activated by QRFP peptides have not been investigated. In the present study, 3T3-L1 adipocytes were used to identify the main pathways involved in QRFP-43 decreasing ISO-induced lipolysis. Our results show that QRFP-43 reduced ISO-induced phosphorylation of perilipin A (PLIN) and hormone-sensitive lipase (HSL) on Ser660 by 43 and 25%, respectively, but increased Akt phosphorylation by 44%. However, the inhibition of phosphodiesterase 3B (PDE3B), a regulator of lipolysis activated by Akt, did not reverse the antilipolytic effect of QRFP-43. PDE3B inhibition reversed the decrease of Ser660 HSL phosphorylation associated with QRFP-43 antilipolytic effect. QRFP-43 also prevented PKC activation and ISO-induced Src kinases activation leading to the inhibition of the caveolin-1 (CAV-1) translocation on lipid droplets. Indeed, QRFP-43 attenuated phorbol 12-myristate 13-acetate-induced lipolysis and ISO-induced extracellular signal-regulated and Src kinases by 28, 37 and 48%, respectively. The attenuation of ISO-induced lipolysis by QRFP-43 was associated with a decrease of phosphorylated Ser660 HSL, PKA-catalytic (PKA-c) subunit and CAV-1 translocation on lipid droplets by 37, 50 and 46%, respectively. The decrease in ISO-induced CAV-1 and PKA-c translocation was associated with a reduction of PLIN phosphorylation by 44% in QRFP-43-treated adipocytes. These results suggest that QRFP-43 attenuated ISO-induced lipolysis by preventing the formation of an active complex on lipid droplets and the activation of Src kinases and PKC.
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Affiliation(s)
- Mukandila Mulumba
- Faculty of Pharmacy, Université de Montréal C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, Department of Medical Sciences, University of Turin, Corso Dogliotti 14, Turin 10126, Italy
| | - Sylvie Marleau
- Faculty of Pharmacy, Université de Montréal C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - Huy Ong
- Faculty of Pharmacy, Université de Montréal C.P. 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada.
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122
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Locher L, Häussler S, Laubenthal L, Singh S, Winkler J, Kinoshita A, Kenéz Á, Rehage J, Huber K, Sauerwein H, Dänicke S. Effect of increasing body condition on key regulators of fat metabolism in subcutaneous adipose tissue depot and circulation of nonlactating dairy cows. J Dairy Sci 2015; 98:1057-68. [DOI: 10.3168/jds.2014-8710] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 10/24/2014] [Indexed: 01/30/2023]
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123
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Najt CP, Lwande JS, McIntosh AL, Senthivinayagam S, Gupta S, Kuhn LA, Atshaves BP. Structural and functional assessment of perilipin 2 lipid binding domain(s). Biochemistry 2014; 53:7051-66. [PMID: 25338003 PMCID: PMC4238800 DOI: 10.1021/bi500918m] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/22/2014] [Indexed: 12/18/2022]
Abstract
Although perilipin 2 (Plin2) has been shown to bind lipids with high affinity, the Plin2 lipid binding site has yet to be defined. This is of interest since Plin2's affinity for lipids has been suggested to be important for lipid droplet biogenesis and intracellular triacylglycerol accumulation. To define these regions, mouse Plin2 and several deletion mutants expressed as recombinant proteins and in mammalian cells were assessed by molecular modeling, fluorescence binding, circular dichroic, and fluorescence resonance energy transfer techniques to identify the structural and functional requirements for lipid binding. Major findings of this study indicate (1) the N-terminal PAT domain does not bind cholesterol or stearic acid; (2) Plin2 residues 119-251, containing helix α4, the α-β domain, and part of helix α6 form a Plin3-like cleft found to be important for highest affinity lipid binding; (3) both stearic acid and cholesterol interact favorably with the Plin2 cleft formed by conserved residues in helix α6 and adjacent strands, which is common to all the active lipid-binding constructs; and (4) discrete targeting of the Plin2 mutants to lipid droplets supports Plin2 containing two independent, nonoverlapping lipid droplet targeting domains in its central and C-terminal sequences. Thus, the current work reveals specific domains responsible for Plin2-lipid interactions that involves the protein's lipid binding and targeting functions.
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Affiliation(s)
- Charles P. Najt
- Department
of Biochemistry and Molecular Biology and Department of Computer Science
and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Joel S. Lwande
- Department
of Biochemistry and Molecular Biology and Department of Computer Science
and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Avery L. McIntosh
- Physiology and Pharmacology, Texas A&M
University, TVMC College Station, Texas 77843-4466, United States
| | - Subramanian Senthivinayagam
- Department
of Biochemistry and Molecular Biology and Department of Computer Science
and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Shipra Gupta
- Department
of Biochemistry and Molecular Biology and Department of Computer Science
and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Leslie A. Kuhn
- Department
of Biochemistry and Molecular Biology and Department of Computer Science
and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Barbara P. Atshaves
- Department
of Biochemistry and Molecular Biology and Department of Computer Science
and Engineering, Michigan State University, East Lansing, Michigan 48824, United States
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124
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López-Yoldi M, Fernández-Galilea M, Laiglesia LM, Larequi E, Prieto J, Martínez JA, Bustos M, Moreno-Aliaga MJ. Cardiotrophin-1 stimulates lipolysis through the regulation of main adipose tissue lipases. J Lipid Res 2014; 55:2634-43. [PMID: 25351614 DOI: 10.1194/jlr.m055335] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cardiotrophin-1 (CT-1) is a cytokine with antiobesity properties and with a role in lipid metabolism regulation and adipose tissue function. The aim of this study was to analyze the molecular mechanisms involved in the lipolytic actions of CT-1 in adipocytes. Recombinant CT-1 (rCT-1) effects on the main proteins and signaling pathways involved in the regulation of lipolysis were evaluated in 3T3-L1 adipocytes and in mice. rCT-1 treatment stimulated basal glycerol release in a concentration- and time-dependent manner in 3T3-L1 adipocytes. rCT-1 (20 ng/ml for 24 h) raised cAMP levels, and in parallel increased protein kinase (PK)A-mediated phosphorylation of perilipin and hormone sensitive lipase (HSL) at Ser660. siRNA knock-down of HSL or PKA, as well as pretreatment with the PKA inhibitor H89, blunted the CT-1-induced lipolysis, suggesting that the lipolytic action of CT-1 in adipocytes is mainly mediated by activation of HSL through the PKA pathway. In ob/ob mice, acute rCT-1 treatment also promoted PKA-mediated phosphorylation of perilipin and HSL at Ser660 and Ser563, and increased adipose triglyceride lipase (desnutrin) content in adipose tissue. These results showed that the ability of CT-1 to regulate the activity of the main lipases underlies the lipolytic action of this cytokine in vitro and in vivo, and could contribute to CT-1 antiobesity effects.
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Affiliation(s)
- Miguel López-Yoldi
- Departments of Nutrition, Food Science, and Physiology University of Navarra, Pamplona, Navarra, Spain Centre for Nutrition Research, University of Navarra, Pamplona, Navarra, Spain
| | - Marta Fernández-Galilea
- Departments of Nutrition, Food Science, and Physiology University of Navarra, Pamplona, Navarra, Spain
| | - Laura M Laiglesia
- Departments of Nutrition, Food Science, and Physiology University of Navarra, Pamplona, Navarra, Spain Centre for Nutrition Research, University of Navarra, Pamplona, Navarra, Spain
| | - Eduardo Larequi
- Gene Therapy and Hepatology, CIMA, University of Navarra, Pamplona, Navarra, Spain
| | - Jesús Prieto
- Gene Therapy and Hepatology, CIMA, University of Navarra, Pamplona, Navarra, Spain CIBERehd Institute of Health Carlos III, Madrid, Spain
| | - J Alfredo Martínez
- Departments of Nutrition, Food Science, and Physiology University of Navarra, Pamplona, Navarra, Spain Centre for Nutrition Research, University of Navarra, Pamplona, Navarra, Spain CIBERobn, Physiopathology of Obesity and Nutrition, Institute of Health Carlos III, Madrid, Spain
| | - Matilde Bustos
- Gene Therapy and Hepatology, CIMA, University of Navarra, Pamplona, Navarra, Spain
| | - Maria J Moreno-Aliaga
- Departments of Nutrition, Food Science, and Physiology University of Navarra, Pamplona, Navarra, Spain Centre for Nutrition Research, University of Navarra, Pamplona, Navarra, Spain CIBERobn, Physiopathology of Obesity and Nutrition, Institute of Health Carlos III, Madrid, Spain
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125
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Yao Z, Zhang L, Ji G. Efficacy of polyphenolic ingredients of Chinese herbs in treating dyslipidemia of metabolic syndromes. JOURNAL OF INTEGRATIVE MEDICINE-JIM 2014; 12:135-46. [PMID: 24861834 DOI: 10.1016/s2095-4964(14)60023-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
There is an increasing interest and popularity of Chinese herbal medicine worldwide, which is accompanied by increasing concerns about its effectiveness and potential toxicity. Several ingredients, such as polyphenolic compounds berberine, flavonoids, and curcumin, have been studied extensively by using various animal models. Effectiveness of treatment and amelioration of metabolic syndromes, including insulin resistance and dyslipidemia, has been demonstrated. This review summarizes the major checkpoints and contributing factors in regulation of exogenous and endogenous lipid metabolism, with particular emphasis centered on triglyceride-rich and cholesterol-rich lipoproteins. Available experimental evidence demonstrating the lipid-lowering effect of berberine, flavonoids and curcumin in cell culture and animal models is compiled, and the strengths and shortcomings of experimental designs in these studies are discussed.
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Affiliation(s)
- Zemin Yao
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of System Biology, University of Ottawa, Ottawa K1H 8M5, Canada; E-mail:
| | - Li Zhang
- Institute of Digestive Diseases, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
| | - Guang Ji
- Institute of Digestive Diseases, Shanghai University of Traditional Chinese Medicine, Shanghai 200032, China
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126
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Ursolic Acid-Regulated Energy Metabolism-Reliever or Propeller of Ultraviolet-Induced Oxidative Stress and DNA Damage? Proteomes 2014; 2:399-425. [PMID: 28250388 PMCID: PMC5302752 DOI: 10.3390/proteomes2030399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 06/12/2014] [Accepted: 07/29/2014] [Indexed: 01/27/2023] Open
Abstract
Ultraviolet (UV) light is a leading cause of diseases, such as skin cancers and cataracts. A main process mediating UV-induced pathogenesis is the production of reactive oxygen species (ROS). Excessive ROS levels induce the formation of DNA adducts (e.g., pyrimidine dimers) and result in stalled DNA replication forks. In addition, ROS promotes phosphorylation of tyrosine kinase-coupled hormone receptors and alters downstream energy metabolism. With respect to the risk of UV-induced photocarcinogenesis and photodamage, the antitumoral and antioxidant functions of natural compounds become important for reducing UV-induced adverse effects. One important question in the field is what determines the differential sensitivity of various types of cells to UV light and how exogenous molecules, such as phytochemicals, protect normal cells from UV-inflicted damage while potentiating tumor cell death, presumably via interaction with intracellular target molecules and signaling pathways. Several endogenous molecules have emerged as possible players mediating UV-triggered DNA damage responses. Specifically, UV activates the PIKK (phosphatidylinositol 3-kinase-related kinase) family members, which include DNA-PKcs, ATM (ataxia telangiectasia mutated) and mTOR (mammalian target of rapamycin), whose signaling can be affected by energy metabolism; however, it remains unclear to what extent the activation of hormone receptors regulates PIKKs and whether this crosstalk occurs in all types of cells in response to UV. This review focuses on proteomic descriptions of the relationships between cellular photosensitivity and the phenotypic expression of the insulin/insulin-like growth receptor. It covers the cAMP-dependent pathways, which have recently been shown to regulate the DNA repair machinery through interactions with the PIKK family members. Finally, this review provides a strategic illustration of how UV-induced mitogenic activity is modulated by the insulin sensitizer, ursolic acid (UA), which results in the metabolic adaptation of normal cells against UV-induced ROS, and the metabolic switch of tumor cells subject to UV-induced damage. The multifaceted natural compound, UA, specifically inhibits photo-oxidative DNA damage in retinal pigment epithelial cells while enhancing that in skin melanoma. Considering the UA-mediated differential effects on cell bioenergetics, this article reviews the disparities in glucose metabolism between tumor and normal cells, along with (peroxisome proliferator-activated receptor-γ coactivator 1α)-dependent mitochondrial metabolism and redox (reduction-oxidation) control to demonstrate UA-induced synthetic lethality in tumor cells.
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127
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Zhang J, Liu F. Tissue-specific insulin signaling in the regulation of metabolism and aging. IUBMB Life 2014; 66:485-95. [PMID: 25087968 DOI: 10.1002/iub.1293] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 07/14/2014] [Indexed: 12/30/2022]
Abstract
In mammals, insulin signaling regulates glucose homeostasis and plays an essential role in metabolism, organ growth, development, fertility, and lifespan. The defects in this signaling pathway contribute to various metabolic diseases such as type 2 diabetes, polycystic ovarian disease, hypertension, hyperlipidemia, and atherosclerosis. However, reducing the insulin signaling pathway has been found to increase longevity and delay the aging-associated diseases in various animals, ranging from nematodes to mice. These seemly paradoxical findings raise an interesting question as to how modulation of the insulin signaling pathway could be an effective approach to improve metabolism and aging. In this review, we summarize current understanding on tissue-specific functions of insulin signaling in the regulation of metabolism and lifespan. We also discuss the potential benefits and limitations in modulating tissue-specific insulin signaling pathway to improve metabolism and healthspan.
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Affiliation(s)
- Jingjing Zhang
- Metabolic Syndrome Research Center, Key Laboratory of Diabetes Immunology, Ministry of Education; Diabetes Center, Institute of Metabolism and Endocrinology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
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128
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Wu LE, Meoli CC, Mangiafico SP, Fazakerley DJ, Cogger VC, Mohamad M, Pant H, Kang MJ, Powter E, Burchfield JG, Xirouchaki CE, Mikolaizak AS, Stöckli J, Kolumam G, van Bruggen N, Gamble JR, Le Couteur DG, Cooney GJ, Andrikopoulos S, James DE. Systemic VEGF-A neutralization ameliorates diet-induced metabolic dysfunction. Diabetes 2014; 63:2656-67. [PMID: 24696450 DOI: 10.2337/db13-1665] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The vascular endothelial growth factor (VEGF) family of cytokines are important regulators of angiogenesis that have emerged as important targets for the treatment of obesity. While serum VEGF levels rise during obesity, recent studies using genetic models provide conflicting evidence as to whether VEGF prevents or accelerates metabolic dysfunction during obesity. In the current study, we sought to identify the effects of VEGF-A neutralization on parameters of glucose metabolism and insulin action in a dietary mouse model of obesity. Within only 72 h of administration of the VEGF-A-neutralizing monoclonal antibody B.20-4.1, we observed almost complete reversal of high-fat diet-induced insulin resistance principally due to improved insulin sensitivity in the liver and in adipose tissue. These effects were independent of changes in whole-body adiposity or insulin signaling. These findings show an important and unexpected role for VEGF in liver insulin resistance, opening up a potentially novel therapeutic avenue for obesity-related metabolic disease.
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Affiliation(s)
- Lindsay E Wu
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, AustraliaLaboratory for Ageing Research, School of Medical Sciences, UNSW Australia, New South Wales, Australia
| | - Christopher C Meoli
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Salvatore P Mangiafico
- Department of Medicine (Austin Health), The University of Melbourne, Heidelberg, Victoria, Australia
| | - Daniel J Fazakerley
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Victoria C Cogger
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Concord, New South Wales, Australia
| | - Mashani Mohamad
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Concord, New South Wales, AustraliaFaculty of Pharmacy, Universiti Teknologi MARA, Bandar Puncak Alam, Selangor, Malaysia
| | - Himani Pant
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Myung-Jin Kang
- Laboratory for Ageing Research, School of Medical Sciences, UNSW Australia, New South Wales, Australia
| | - Elizabeth Powter
- Centre for the Endothelium, Vascular Biology Program, Centenary Institute, and The University of Sydney, Sydney, Australia
| | - James G Burchfield
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | | | - A Stefanie Mikolaizak
- Falls and Balance Research Group, Neuroscience Research Australia, Sydney, Australia
| | - Jacqueline Stöckli
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Ganesh Kolumam
- Department of Biomedical Imaging, Genentech Inc., San Francisco, CA
| | | | - Jennifer R Gamble
- Centre for the Endothelium, Vascular Biology Program, Centenary Institute, and The University of Sydney, Sydney, Australia
| | - David G Le Couteur
- Centre for Education and Research on Ageing and ANZAC Medical Research Institute, University of Sydney and Concord Hospital, Concord, New South Wales, Australia
| | - Gregory J Cooney
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Sofianos Andrikopoulos
- Department of Medicine (Austin Health), The University of Melbourne, Heidelberg, Victoria, Australia
| | - David E James
- Diabetes and Obesity Program, Garvan Institute of Medical Research, Darlinghurst, New South Wales, AustraliaCharles Perkins Centre, School of Molecular Bioscience, The University of Sydney, Sydney, Australia
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Nielsen TS, Jessen N, Jørgensen JOL, Møller N, Lund S. Dissecting adipose tissue lipolysis: molecular regulation and implications for metabolic disease. J Mol Endocrinol 2014; 52:R199-222. [PMID: 24577718 DOI: 10.1530/jme-13-0277] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipolysis is the process by which triglycerides (TGs) are hydrolyzed to free fatty acids (FFAs) and glycerol. In adipocytes, this is achieved by sequential action of adipose TG lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase. The activity in the lipolytic pathway is tightly regulated by hormonal and nutritional factors. Under conditions of negative energy balance such as fasting and exercise, stimulation of lipolysis results in a profound increase in FFA release from adipose tissue (AT). This response is crucial in order to provide the organism with a sufficient supply of substrate for oxidative metabolism. However, failure to efficiently suppress lipolysis when FFA demands are low can have serious metabolic consequences and is believed to be a key mechanism in the development of type 2 diabetes in obesity. As the discovery of ATGL in 2004, substantial progress has been made in the delineation of the remarkable complexity of the regulatory network controlling adipocyte lipolysis. Notably, regulatory mechanisms have been identified on multiple levels of the lipolytic pathway, including gene transcription and translation, post-translational modifications, intracellular localization, protein-protein interactions, and protein stability/degradation. Here, we provide an overview of the recent advances in the field of AT lipolysis with particular focus on the molecular regulation of the two main lipases, ATGL and HSL, and the intracellular and extracellular signals affecting their activity.
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Affiliation(s)
- Thomas Svava Nielsen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Jessen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, DenmarkThe Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Jens Otto L Jørgensen
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Niels Møller
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
| | - Sten Lund
- The Novo Nordisk Foundation Center for Basic Metabolic ResearchSection on Integrative Physiology, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3b, 6.6.30, DK-2200 N Copenhagen, DenmarkDepartment of Endocrinology and Internal MedicineAarhus University Hospital, Nørrebrogade 44, Bldg. 3.0, 8000 Aarhus C, DenmarkDepartment of Molecular MedicineAarhus University Hospital, Brendstrupgårdsvej 100, 8200 Aarhus N, Denmark
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Abstract
There has been an upsurge of interest in the adipocyte coincident with the onset of the obesity epidemic and the realization that adipose tissue plays a major role in the regulation of metabolic function. The past few years, in particular, have seen significant changes in the way that we classify adipocytes and how we view adipose development and differentiation. We have new perspective on the roles played by adipocytes in a variety of homeostatic processes and on the mechanisms used by adipocytes to communicate with other tissues. Finally, there has been significant progress in understanding how these relationships are altered during metabolic disease and how they might be manipulated to restore metabolic health.
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Affiliation(s)
- Evan D Rosen
- Division of Endocrinology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA; Departments of Genetics and Cell Biology, Harvard Medical School, Boston, MA 02215, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
| | - Bruce M Spiegelman
- Departments of Genetics and Cell Biology, Harvard Medical School, Boston, MA 02215, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
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131
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Aberdein N, Schweizer M, Ball D. Sodium acetate decreases phosphorylation of hormone sensitive lipase in isoproterenol-stimulated 3T3-L1 mature adipocytes. Adipocyte 2014; 3:121-5. [PMID: 24719785 DOI: 10.4161/adip.27936] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 01/12/2014] [Accepted: 01/21/2014] [Indexed: 12/26/2022] Open
Abstract
Lipolysis, the process of hydrolysis of stored triacylglycerol into glycerol and non-esterified fatty acids (NEFA), is reported to be reduced by short chain fatty acids (SCFA) but the mechanism of this inhibition is poorly understood. The aim of this study was to measure the phosphorylation at serine residue 563 of hormone sensitive lipase with and without exposure to sodium acetate. Using the 3T3-L1 cell line, we identified that stimulating the cells with isoproterenol increased phosphorylated hormone sensitive lipase (pHSL) expression by 60% compared with the basal state. In the presence of the SCFA acetate in stimulated cells, pHSL decreased by 15% compared with stimulated cells alone. These results were mirrored by the NEFA release from stimulated cells that had significantly decreased in the presence of sodium acetate after 60 min (from 0.53 µmol mg(-1) protein to 0.41 µmol mg(-1) protein, respectively, P = 0.004); and 180 min (1.73 µmol mg(-1) protein to 1.13 µmol mg(-1) protein, P = 0.020); however, treatment had no effect on glycerol release (P = 0.109). In conclusion, exposure to 4 mM acetate reduced the level of phosphorylation of HSL(SER563) in mature 3T3-L1 adipocytes and led to a significant reduction in NEFA release, although glycerol release was not affected.
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132
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Akbar H, Cardoso FC, Meier S, Burke C, McDougall S, Mitchell M, Walker C, Rodriguez-Zas SL, Everts RE, Lewin HA, Roche JR, Loor JJ. Postpartal subclinical endometritis alters transcriptome profiles in liver and adipose tissue of dairy cows. Bioinform Biol Insights 2014; 8:45-63. [PMID: 24578603 PMCID: PMC3934763 DOI: 10.4137/bbi.s13735] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 12/17/2013] [Accepted: 12/17/2013] [Indexed: 12/11/2022] Open
Abstract
Transcriptome alterations in liver and adipose tissue of cows with subclinical endometritis (SCE) at 29 d postpartum were evaluated. Bioinformatics analysis was performed using the Dynamic Impact Approach by means of KEGG and DAVID databases. Milk production, blood metabolites (non-esterified fatty acids, magnesium), and disease biomarkers (albumin, aspartate aminotransferase) did not differ greatly between healthy and SCE cows. In liver tissue of cows with SCE, alterations in gene expression revealed an activation of complement and coagulation cascade, steroid hormone biosynthesis, apoptosis, inflammation, oxidative stress, MAPK signaling, and the formation of fibrinogen complex. Bioinformatics analysis also revealed an inhibition of vitamin B3 and B6 metabolism with SCE. In adipose, the most activated pathways by SCE were nicotinate and nicotinamide metabolism, long-chain fatty acid transport, oxidative phosphorylation, inflammation, T cell and B cell receptor signaling, and mTOR signaling. Results indicate that SCE in dairy cattle during early lactation induces molecular alterations in liver and adipose tissue indicative of immune activation and cellular stress.
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Affiliation(s)
- Haji Akbar
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
| | - Felipe C. Cardoso
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
| | | | | | | | - Murray Mitchell
- Liggins Institute, University of Auckland, Auckland, New Zealand
- University of Queensland Centre for Clinical Research, Brisbane, St. Lucia, Queensland, Australia
| | | | | | - Robin E. Everts
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
| | - Harris A. Lewin
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
| | | | - Juan J. Loor
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois, USA
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133
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Liu JC, Yu Y, Wang G, Wang K, Yang XG. Bis(acetylacetonato)-oxovanadium(iv), bis(maltolato)-oxovanadium(iv) and sodium metavanadate induce antilipolytic effects by regulating hormone-sensitive lipase and perilipin via activation of Akt. Metallomics 2014; 5:813-20. [PMID: 23576171 DOI: 10.1039/c3mt00001j] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The increased plasma free fatty acid levels due to the deregulated lipolysis in adipocytes are considered as one of the major risk factors for developing type II diabetes. Vanadium compounds are well-known for their antidiabetic effects both on glucose and lipid metabolism, but the mechanisms are still not completely understood. The present study suggests a mechanism for how vanadium compounds exert antilipolytic effects. It demonstrates that all the three vanadium compounds, bis(acetylacetonato)-oxovanadium(iv) (VO(acac)2), bis(maltolato)-oxovanadium(iv) (VO(ma)2) and sodium metavanadate (NaVO3), attenuated basal lipolysis in 3T3L1 adipocytes in a dose- (from 100 to 400 μM for VO(acac)2 and VO(ma)2, 1.0 to 4.0 mM for vanadate) and time-dependent (from 0.5 to 4 h) manner using the glycerol release as a marker of lipolysis. In addition, the three compounds inhibited lipolysis to a different extent. Among them, VO(acac)2 (from 100 to 400 μM) exerted the most potent effect and reduced the lipolysis to ∼60-20% of control after 4 h treatment. The antilipolytic effects of vanadium compounds were further evidenced by a decrease of the levels of phosphorylated HSL at Ser660 and phosphorylated perilipin, which were counteracted by inhibitors of PI3K or Akt but not by an MEK inhibitor. This indicates that though both Akt and ERK pathways are activated by the vanadium compounds, only Akt activation contributes to the antilipolytic effect of the vanadium compounds, without the involvement of ERK activation. We previously demonstrated that VO(acac)2 can block cell cycle progression at the G1/S phase via a highly activated ERK signal in human hepatoma HepG2 cells. Together with this study, we show that similar activated pathways may lead to differential biological consequences for cancer cells and adipocytes, indicating that vanadium compounds may be used in the prevention and treatment of both diabetes and cancer.
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Affiliation(s)
- Jing-Cheng Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, People's Republic of China
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134
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Pan MH, Lai CS, Tsai ML, Ho CT. Chemoprevention of nonalcoholic fatty liver disease by dietary natural compounds. Mol Nutr Food Res 2013; 58:147-71. [PMID: 24302567 DOI: 10.1002/mnfr.201300522] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/25/2013] [Accepted: 10/09/2013] [Indexed: 02/06/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) refers to a wide spectrum of liver disease that is not from excess alcohol consumption, but is often associated with obesity, type 2 diabetes, and metabolic syndrome. NAFLD pathogenesis is complicated and involves oxidative stress, lipotoxicity, mitochondrial damage, insulin resistance, inflammation, and excessive dietary fat intake, which increase hepatic lipid influx and de novo lipogenesis and impair insulin signaling, thus promoting hepatic triglyceride accumulation and ultimately NAFLD. Overproduction of proinflammatory adipokines from adipose tissue also affects hepatic metabolic function. Current NAFLD therapies are limited; thus, much attention has been focused on identification of potential dietary substances from fruits, vegetables, and edible plants to provide a new strategy for NAFLD treatment. Dietary natural compounds, such as carotenoids, omega-3-PUFAs, flavonoids, isothiocyanates, terpenoids, curcumin, and resveratrol, act through a variety of mechanisms to prevent and improve NAFLD. Here, we summarize and briefly discuss the currently known targets and signaling pathways as well as the role of dietary natural compounds that interfere with NAFLD pathogenesis.
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Affiliation(s)
- Min-Hsiung Pan
- Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan
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135
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Houser DS, Champagne CD, Crocker DE. A non-traditional model of the metabolic syndrome: the adaptive significance of insulin resistance in fasting-adapted seals. Front Endocrinol (Lausanne) 2013; 4:164. [PMID: 24198811 PMCID: PMC3814516 DOI: 10.3389/fendo.2013.00164] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/17/2013] [Indexed: 11/13/2022] Open
Abstract
Insulin resistance in modern society is perceived as a pathological consequence of excess energy consumption and reduced physical activity. Its presence in relation to the development of cardiovascular risk factors has been termed the metabolic syndrome, which produces increased mortality and morbidity and which is rapidly increasing in human populations. Ironically, insulin resistance likely evolved to assist animals during food shortages by increasing the availability of endogenous lipid for catabolism while protecting protein from use in gluconeogenesis and eventual oxidation. Some species that incorporate fasting as a predictable component of their life history demonstrate physiological traits similar to the metabolic syndrome during prolonged fasts. One such species is the northern elephant seal (Mirounga angustirostris), which fasts from food and water for periods of up to 4 months. During this time, ∼90% of the seals metabolic demands are met through fat oxidation and circulating non-esterified fatty acids are high (0.7-3.2 mM). All life history stages of elephant seal studied to date demonstrate insulin resistance and fasting hyperglycemia as well as variations in hormones and adipocytokines that reflect the metabolic syndrome to some degree. Elephant seals demonstrate some intriguing adaptations with the potential for medical advancement; for example, ketosis is negligible despite significant and prolonged fatty acid oxidation and investigation of this feature might provide insight into the treatment of diabetic ketoacidosis. The parallels to the metabolic syndrome are likely reflected to varying degrees in other marine mammals, most of which evolved on diets high in lipid and protein content but essentially devoid of carbohydrate. Utilization of these natural models of insulin resistance may further our understanding of the pathophysiology of the metabolic syndrome in humans and better assist the development of preventative measures and therapies.
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Affiliation(s)
- Dorian S. Houser
- Department of Conservation and Biological Research, National Marine Mammal Foundation, San Diego, CA, USA
- *Correspondence: Dorian S. Houser, Department of Conservation and Biological Research, National Marine Mammal Foundation, 2240 Shelter Island Drive, Suite 200, San Diego, CA 92106, USA e-mail:
| | - Cory D. Champagne
- Department of Conservation and Biological Research, National Marine Mammal Foundation, San Diego, CA, USA
| | - Daniel E. Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
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136
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Yang P, Patrick E, Tan SX, Fazakerley DJ, Burchfield J, Gribben C, Prior MJ, James DE, Hwa Yang Y. Direction pathway analysis of large-scale proteomics data reveals novel features of the insulin action pathway. ACTA ACUST UNITED AC 2013; 30:808-14. [PMID: 24167158 DOI: 10.1093/bioinformatics/btt616] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
MOTIVATION With the advancement of high-throughput techniques, large-scale profiling of biological systems with multiple experimental perturbations is becoming more prevalent. Pathway analysis incorporates prior biological knowledge to analyze genes/proteins in groups in a biological context. However, the hypotheses under investigation are often confined to a 1D space (i.e. up, down, either or mixed regulation). Here, we develop direction pathway analysis (DPA), which can be applied to test hypothesis in a high-dimensional space for identifying pathways that display distinct responses across multiple perturbations. RESULTS Our DPA approach allows for the identification of pathways that display distinct responses across multiple perturbations. To demonstrate the utility and effectiveness, we evaluated DPA under various simulated scenarios and applied it to study insulin action in adipocytes. A major action of insulin in adipocytes is to regulate the movement of proteins from the interior to the cell surface membrane. Quantitative mass spectrometry-based proteomics was used to study this process on a large-scale. The combined dataset comprises four separate treatments. By applying DPA, we identified that several insulin responsive pathways in the plasma membrane trafficking are only partially dependent on the insulin-regulated kinase Akt. We subsequently validated our findings through targeted analysis of key proteins from these pathways using immunoblotting and live cell microscopy. Our results demonstrate that DPA can be applied to dissect pathway networks testing diverse hypotheses and integrating multiple experimental perturbations. AVAILABILITY AND IMPLEMENTATION The R package 'directPA' is distributed from CRAN under GNU General Public License (GPL)-3 and can be downloaded from: http://cran.r-project.org/web/packages/directPA/index.html CONTACT jean.yang@sydney.edu.au SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Pengyi Yang
- Systems Biology Group, Biostatistics Branch, National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, NC 27709, USA, School of Mathematics and Statistics, University of Sydney, Diabetes and Obesity Program, Garvan Institute of Medical Research, NSW 2006, Australia and Metabolism in Human Disease Unit, Institute of Molecular and Cellular Biology, A*Star, 61 Biopolis Drive, Proteos 138673, Singapore
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137
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Awoniyi O, Rehman R, Dagogo-Jack S. Hypoglycemia in patients with type 1 diabetes: epidemiology, pathogenesis, and prevention. Curr Diab Rep 2013; 13:669-78. [PMID: 23912765 DOI: 10.1007/s11892-013-0411-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hypoglycemia is uncommon in the general, nondiabetic population but occurs frequently in persons with diabetes treated with insulin or insulin secretagogues. Thus, iatrogenic hypoglycemia explains the majority of cases among persons with type 1 diabetes (T1DM). Since T1DM is characterized by absolute insulin dependence, the current imperfections in insulin replacement therapies often lead to a mismatch between caloric supply and circulating insulin levels, thus increasing the risk for glycemic fluctuations. Hypoglycemia is the limiting factor to excellent glycemic control in insulin-treated subjects. Intensification of glycemic control was associated with a 300 % increase in the rate of hypoglycemia in the Diabetes Control and Complications Trial. Recent measurements using continuous glucose monitoring reveal an alarming rate of daytime and nocturnal episodes of hypoglycemia in patients with T1DM. Etiological factors underlying hypoglycemia in T1DM include predictable triggers (skipped meals, exercise, insulin over dosage) as well as defective counterregulation, a component of hypoglycemia-associated autonomic failure.
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Affiliation(s)
- Omodele Awoniyi
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism & Clinical Research Center, University of Tennessee Health Science Center, 920 Madison Avenue, Suite 300A, Memphis, TN, 38163, USA
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138
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Insulin inhibits lipolysis in adipocytes via the evolutionarily conserved mTORC1-Egr1-ATGL-mediated pathway. Mol Cell Biol 2013; 33:3659-66. [PMID: 23858058 DOI: 10.1128/mcb.01584-12] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
One of the basic functions of insulin in the body is to inhibit lipolysis in adipocytes. Recently, we have found that insulin inhibits lipolysis and promotes triglyceride storage by decreasing transcription of adipose triglyceride lipase via the mTORC1-mediated pathway (P. Chakrabarti et al., Diabetes 59:775-781, 2010), although the mechanism of this effect remained unknown. Here, we used a genetic screen in Saccharomyces cerevisiae in order to identify a transcription factor that mediates the effect of Tor1 on the expression of the ATGL ortholog in yeast. This factor, Msn4p, has homologues in mammalian cells that form a family of early growth response transcription factors. One member of the family, Egr1, is induced by insulin and nutrients and directly inhibits activity of the ATGL promoter in vitro and expression of ATGL in cultured adipocytes. Feeding animals a high-fat diet increases the activity of mTORC1 and the expression of Egr1 while decreasing ATGL levels in epididymal fat. We suggest that the evolutionarily conserved mTORC1-Egr1-ATGL regulatory pathway represents an important component of the antilipolytic effect of insulin in the mammalian organism.
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139
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McCurdy CE, Klemm DJ. Adipose tissue insulin sensitivity and macrophage recruitment: Does PI3K pick the pathway? Adipocyte 2013; 2:135-42. [PMID: 23991359 PMCID: PMC3756101 DOI: 10.4161/adip.24645] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/09/2013] [Accepted: 04/10/2013] [Indexed: 02/06/2023] Open
Abstract
In the United States, obesity is a burgeoning health crisis, with over 30% of adults and nearly 20% of children classified as obese. Insulin resistance, a common metabolic complication associated with obesity, significantly increases the risk of developing metabolic diseases such as hypertension, coronary heart disease, stroke, type 2 diabetes, and certain cancers. With the seminal finding that obese adipose tissue harbors cytokine secreting immune cells, obesity-related research over the past decade has focused on understanding adipocyte–macrophage crosstalk and its impact on systemic insulin sensitivity. Indeed, adipose tissue has emerged as a central mediator of obesity- and diet-induced insulin resistance. In this mini-review, we focus on a potential role of adipose tissue phosphoinositide 3-kinase (PI3K) as a point of convergence of cellular signaling pathways that integrates nutrient sensing and inflammatory signaling to regulate tissue insulin sensitivity.
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140
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Boyda HN, Procyshyn RM, Pang CCY, Barr AM. Peripheral adrenoceptors: the impetus behind glucose dysregulation and insulin resistance. J Neuroendocrinol 2013; 25:217-28. [PMID: 23140239 DOI: 10.1111/jne.12002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 10/10/2012] [Accepted: 11/04/2012] [Indexed: 12/20/2022]
Abstract
It is now accepted that several pharmacological drug treatments trigger clinical manifestations of glucose dysregulation, such as hyperglycaemia, glucose intolerance and insulin resistance, in part through poorly understood mechanisms. Persistent sympathoadrenal activation is linked to glucose dysregulation and insulin resistance, both of which significantly increase the risk of emergent endocrinological disorders, including metabolic syndrome and type 2 diabetes mellitus. Through the use of targeted mutagenesis and pharmacological methods, preclinical and clinical research has confirmed physiological glucoregulatory roles for several peripheral α- and β-adrenoceptor subtypes. Adrenoceptor isoforms in the pancreas (α(2A) and β(2) ), skeletal muscle (α(1A) and β(2) ), liver (α(1A & B) and β(2) ) and adipose tissue (α(1A) and β(1 & 3) ) are convincing aetiological targets that account for both immediate and long-lasting alterations in blood glucose homeostasis. Because significant overlap exists between the therapeutic applications of numerous classes of drugs and their associated adverse side-effects, a better understanding of peripheral adrenoceptor-mediated glucose metabolism is thus warranted. Therefore, at the same time as providing a brief review of glucose homeostasis in the periphery, the present review addresses both functional and pathophysiological roles of the mammalian α(1) , α(2) , and β-adrenoceptor isoforms in whole-body glucose turnover. We highlight evidence relating to the clinical use of common adrenergic drugs and their impacts on glucose metabolism.
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Affiliation(s)
- H N Boyda
- Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, Canada.
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141
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Rosmaninho-Salgado J, Cortez V, Estrada M, Santana MM, Gonçalves A, Marques AP, Cavadas C. Intracellular mechanisms coupled to NPY Y2 and Y5 receptor activation and lipid accumulation in murine adipocytes. Neuropeptides 2012; 46:359-66. [PMID: 22981159 DOI: 10.1016/j.npep.2012.08.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 07/28/2012] [Accepted: 08/08/2012] [Indexed: 12/23/2022]
Abstract
The formation of adipose tissue is a process that includes the pre-adipocyte proliferation and differentiation to adipocytes that are cells specialized in lipid accumulation. The adipocyte differentiation is a process driven by the coordinated expression of various transcription factors, such as peroxisome proliferator-activated receptor (PPAR-γ). Neuropeptide Y (NPY) induces adipocyte proliferation and differentiation but the NPY receptors and the intracellular pathways involved in these processes are still not clear. In the present work we studied the role of NPY receptors and the intracellular pathways involved in the stimulatory effect of NPY on lipid accumulation. The murine pre-adipocyte cell line, 3T3-L1, was used as a cell model. Adipogenesis was evaluated by quantifying lipid accumulation by Oil red-O assay and by analyzing PPAR-γ expression using the Western blotting assay. Adipocytes were incubated with NPY (100nM) and a decrease on lipid accumulation and PPAR-γ expression was observed in the presence of NPY Y(2) receptor antagonist (BIIE0246, 1μM) or NPY Y(5) antagonist. Furthermore, NPY Y(2) (NPY(3-36), 100nM) or NPY Y(5) (NPY(19-23)(GLY(1), Ser(3), Gln(4), Thr(6), Ala(31), Aib(32), Gln(34)) PP, 100nM) receptor agonists increased lipid accumulation and PPAR-γ expression. We further investigate the intracellular pathways associated with NPY Y(2) and NPY Y(5) receptor activation. Our results show NPY induces PPAR-γ expression and lipid accumulation through NPY Y(2) and NPY Y(5) receptors activation. PKC and PLC inhibitors inhibit lipid accumulation induced by NPY Y(5) receptor agonist. Moreover, our results suggest that lipid accumulation induced by NPY Y(2) receptor activation occurs through PKA, MAPK and PI3K pathways. In conclusion, this study contributes to a step forward on the knowledge of intracellular mechanisms associated with NPY receptors activation on adipocytes and contributes to a better understanding and the development of new therapeutic targets for obesity treatment.
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142
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Xiong Q, Chai J, Deng C, Jiang S, Liu Y, Huang T, Suo X, Zhang N, Li X, Yang Q, Chen M, Zheng R. Characterization of porcine SKIP gene in skeletal muscle development: Polymorphisms, association analysis, expression and regulation of cell growth in C2C12 cells. Meat Sci 2012; 92:490-7. [DOI: 10.1016/j.meatsci.2012.05.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 04/02/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022]
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143
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Abstract
Current findings from the literature on the multifactorial genesis of macroangiopathy of diabetes mellitus (DM) were compiled using the PubMed database. The primary aim was to find an explanation for the morphological, immunohistochemical and molecular characteristics of this form of atherosclerosis. The roles of advanced glycation end products (AGE), defective signal transduction and imbalance of matrix metalloproteinases in the increased progression of atherosclerosis in coronary and cerebral arteries as well as peripheral vascular disease are discussed. The restricted formation of collateral arteries (arteriogenesis) in diabetic patients with postischemic lesions is also a focus of attention. The increased level of prothrombotic factors and the role of diabetic neuropathy in DM are also taken into account. Therapeutic influences of AGE-RAGE (receptor of AGE) interactions on the vascular wall and the effects of endothelial progenitor cells in the repair of diabetic vascular lesions are additionally highlighted.
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Affiliation(s)
- J Kunz
- Lilienthalstr. 19, 14612, Falkensee, Deutschland.
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144
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Wang X, Huang M, Wang Y. The effect of insulin, TNFα and DHA on the proliferation, differentiation and lipolysis of preadipocytes isolated from large yellow croaker (Pseudosciaena Crocea R.). PLoS One 2012; 7:e48069. [PMID: 23110176 PMCID: PMC3482209 DOI: 10.1371/journal.pone.0048069] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 09/20/2012] [Indexed: 01/19/2023] Open
Abstract
Fish final product can be affected by excessive lipid accumulation. Therefore, it is important to develop strategies to control obesity in cultivated fish to strengthen the sustainability of the aquaculture industry. As in mammals, the development of adiposity in fish depends on hormonal, cytokine and dietary factors. In this study, we investigated the proliferation and differentiation of preadipocytes isolated from the large yellow croaker and examined the effects of critical factors such as insulin, TNFα and DHA on the proliferation, differentiation and lipolysis of adipocytes. Preadipocytes were isolated by collagenase digestion, after which their proliferation was evaluated. The differentiation process was optimized by assaying glycerol-3-phosphate dehydrogenase (GPDH) activity. Oil red O staining and electron microscopy were performed to visualize the accumulated triacylglycerol. Gene transcript levels were measured using SYBR green quantitative real-time PCR. Insulin promoted preadipocytes proliferation, stimulated cell differentiation and decreased lipolysis of mature adipocytes. TNFα and DHA inhibited cell proliferation and differentiation. While TNFα stimulated mature adipocyte lipolysis, DHA showed no lipolytic effect on adipocytes. The expressions of adipose triglyceride lipase (ATGL), fatty acid synthase (FAS), lipoprotein lipase (LPL) and peroxisome proliferator-activated receptor α, γ (PPARα, PPARγ) were quantified during preadipocytes differentiation and adipocytes lipolysis to partly explain the regulation mechanisms. In summary, the results of this study indicated that although preadipocytes proliferation and the differentiation process in large yellow croaker are similar to these processes in mammals, the effects of critical factors such as insulin, TNFα and DHA on fish adipocytes development are not exactly the same. Our findings fill in the gaps in the basic data regarding the effects of critical factors on adiposity development in fish and will facilitate the further study of molecular mechanism by which these factors act in fish and the application of this knowledge to eventually control obesity in cultured species.
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Affiliation(s)
- Xinxia Wang
- Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang Province, People’s Republic of China
| | - Ming Huang
- Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang Province, People’s Republic of China
| | - Yizhen Wang
- Institute of Feed Science, Zhejiang University, Hangzhou, Zhejiang Province, People’s Republic of China
- * E-mail:
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145
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Viscarra JA, Vázquez-Medina JP, Rodriguez R, Champagne CD, Adams SH, Crocker DE, Ortiz RM. Decreased expression of adipose CD36 and FATP1 are associated with increased plasma non-esterified fatty acids during prolonged fasting in northern elephant seal pups (Mirounga angustirostris). ACTA ACUST UNITED AC 2012; 215:2455-64. [PMID: 22723485 DOI: 10.1242/jeb.069070] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The northern elephant seal pup (Mirounga angustirostris) undergoes a 2-3 month post-weaning fast, during which it depends primarily on the oxidation of fatty acids to meet its energetic demands. The concentration of non-esterified fatty acids (NEFAs) increases and is associated with the development of insulin resistance in late-fasted pups. Furthermore, plasma NEFA concentrations respond differentially to an intravenous glucose tolerance test (ivGTT) depending on fasting duration, suggesting that the effects of glucose on lipid metabolism are altered. However, elucidation of the lipolytic mechanisms including lipase activity during prolonged fasting in mammals is scarce. To assess the impact of fasting and glucose on the regulation of lipid metabolism, adipose tissue and plasma samples were collected before and after ivGTTs performed on early (2 weeks, N=5) and late (6-8 weeks; N=8) fasted pups. Glucose administration increased plasma triglycerides and NEFA concentrations in late-fasted seals, but not plasma glycerol. Fasting decreased basal adipose lipase activity by 50%. Fasting also increased plasma lipase activity twofold and decreased the expressions of CD36, FAS, FATP1 and PEPCK-C by 22-43% in adipose tissue. Plasma acylcarnitine profiling indicated that late-fasted seals display higher incomplete LCFA β-oxidation. Results suggest that long-term fasting induces shifts in the regulation of lipolysis and lipid metabolism associated with the onset of insulin resistance in northern elephant seal pups. Delineation of the mechanisms responsible for this shift in regulation during fasting can contribute to a more thorough understanding of the changes in lipid metabolism associated with dyslipidemia and insulin resistance in mammals.
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146
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Oh YB, Kim JH, Park BM, Park BH, Kim SH. Captopril intake decreases body weight gain via angiotensin-(1-7). Peptides 2012; 37:79-85. [PMID: 22743141 DOI: 10.1016/j.peptides.2012.06.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2012] [Revised: 06/11/2012] [Accepted: 06/11/2012] [Indexed: 11/16/2022]
Abstract
Angiotensin-(1-7) [Ang-(1-7)] plays a beneficial role in cardiovascular physiology by providing a counterbalance to the function of angiotensin II (Ang II). Although Ang II has been shown to be an adipokine secreted by adipocyte and affect lipid metabolism, the role of Ang-(1-7) in adipose tissue remains to be clarified. The aim of the present study was to investigate whether Ang-(1-7) affects lipid metabolism in adipose tissue. Ang-(1-7) increased glycerol release from primary adipocytes in a dose-dependent manner. A lipolytic effect of Ang-(1-7) was attenuated by pretreatment with A-779, a Mas receptor blocker and with an inhibitor of phosphoinositol 3-kinase (PI3K), or eNOS. However, losartan and PD123319 did not cause any change in Ang-(1-7)-induced lipolysis. Ang-(1-7)-induced lipolysis had an addictive effect with isoproterenol. In normal rats, chronic intake of captopril for 4 wks decreased body weight gain and the amount of adipose tissue and increased plasma Ang-(1-7) level. These effects were attenuated by administration of A-779. The levels of Mas receptor and phosphorylation of hormone-sensitive lipase (p-HSL) were significantly increased by treatment with captopril and these captopril-mediated effects were attenuated by the administration of A-779. There was no difference in diameter of adipocytes among sham, captopril- and captopril+A-779-treated groups. The similar effects of captopril on body weight, expression of Mas receptor, and p-HSL were observed in Ang-(1-7)-treated rats. These results suggest that captopril intake decreased body weight gain partly through Ang-(1-7)/Mas receptor/PI3K pathway.
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Affiliation(s)
- Young-Bin Oh
- Department of Physiology, Diabetic Research Center, Chonbuk National University Medical School, Jeonju, Republic of Korea
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147
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Wang JC, Gray NE, Kuo T, Harris CA. Regulation of triglyceride metabolism by glucocorticoid receptor. Cell Biosci 2012; 2:19. [PMID: 22640645 PMCID: PMC3419133 DOI: 10.1186/2045-3701-2-19] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 05/28/2012] [Indexed: 12/11/2022] Open
Abstract
Glucocorticoids are steroid hormones that play critical and complex roles in the regulation of triglyceride (TG) homeostasis. Depending on physiological states, glucocorticoids can modulate both TG synthesis and hydrolysis. More intriguingly, glucocorticoids can concurrently affect these two processes in adipocytes. The metabolic effects of glucocorticoids are conferred by intracellular glucocorticoid receptors (GR). GR is a transcription factor that, upon binding to glucocorticoids, regulates the transcriptional rate of specific genes. These GR primary target genes further initiate the physiological and pathological responses of glucocorticoids. In this article, we overview glucocorticoid-regulated genes, especially those potential GR primary target genes, involved in glucocorticoid-regulated TG metabolism. We also discuss transcriptional regulators that could act with GR to participate in these processes. This knowledge is not only important for the fundamental understanding of steroid hormone actions, but also are essential for future therapeutic interventions against metabolic diseases associated with aberrant glucocorticoid signaling, such as insulin resistance, dyslipidemia, central obesity and hepatic steatosis.
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Affiliation(s)
- Jen-Chywan Wang
- Department of Nutritional Science & Toxicology, University of California at Berkeley, Berkeley, CA, 94720, USA.
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148
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Mohammad S, Ramos LS, Buck J, Levin LR, Rubino F, McGraw TE. Gastric inhibitory peptide controls adipose insulin sensitivity via activation of cAMP-response element-binding protein and p110β isoform of phosphatidylinositol 3-kinase. J Biol Chem 2011; 286:43062-70. [PMID: 22027830 DOI: 10.1074/jbc.m111.289009] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Gastric inhibitory peptide (GIP) is an incretin hormone secreted in response to food intake. The best known function of GIP is to enhance glucose-dependent insulin secretion from pancreatic β-cells. Extra-pancreatic effects of GIP primarily occur in adipose tissues. Here, we demonstrate that GIP increases insulin-dependent translocation of the Glut4 glucose transporter to the plasma membrane and exclusion of FoxO1 transcription factor from the nucleus in adipocytes, establishing that GIP has a general effect on insulin action in adipocytes. Stimulation of adipocytes with GIP alone has no effect on these processes. Using pharmacologic and molecular genetic approaches, we show that the effect of GIP on adipocyte insulin sensitivity requires activation of both the cAMP/protein kinase A/CREB signaling module and p110β phosphoinositol-3' kinase, establishing a novel signal transduction pathway modulating insulin action in adipocytes. This insulin-sensitizing effect is specific for GIP because isoproterenol, which elevates adipocyte cAMP and activates PKA/CREB signaling, does not affect adipocyte insulin sensitivity. The insulin-sensitizing activity points to a more central role for GIP in intestinal regulation of peripheral tissue metabolism, an emerging feature of inter-organ communication in the control of metabolism.
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Affiliation(s)
- Sameer Mohammad
- Department of Biochemistry, Weill Medical College of Cornell University, New York, New York 10065, USA
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149
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Ito M, Nagasawa M, Omae N, Ide T, Akasaka Y, Murakami K. Differential regulation of CIDEA and CIDEC expression by insulin via Akt1/2- and JNK2-dependent pathways in human adipocytes. J Lipid Res 2011; 52:1450-60. [PMID: 21636835 DOI: 10.1194/jlr.m012427] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Both insulin and the cell death-inducing DNA fragmentation factor-α-like effector (CIDE) family play important roles in apoptosis and lipid droplet formation. Previously, we reported that CIDEA and CIDEC are differentially regulated by insulin and contribute separately to insulin-induced anti-apoptosis and lipid droplet formation in human adipocytes. However, the upstream signals of CIDE proteins remain unclear. Here, we investigated the signaling molecules involved in insulin regulation of CIDEA and CIDEC expression. The phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and PI-103 blocked both insulin-induced downregulation of CIDEA and upregulation of CIDEC. The Akt inhibitor API-2 and the c-Jun N-terminal kinase (JNK) inhibitor SP600125 selectively inhibited insulin regulation of CIDEA and CIDEC expression, respectively, whereas the MAPK/ERK kinase inhibitor U0126 and the p38 inhibitor SB203580 did not. Small interfering RNA-mediated depletion of Akt1/2 prevented insulin-induced downregulation of CIDEA and inhibition of apoptosis. Depletion of JNK2, but not JNK1, inhibited insulin-induced upregulation of CIDEC and lipid droplet enlargement. Furthermore, insulin increased both Akt and JNK phosphorylation, which was abrogated by the PI3K inhibitors. These results suggest that insulin regulates CIDEA and CIDEC expression via PI3K, and it regulates expression of each protein via Akt1/2- and JNK2-dependent pathways, respectively, in human adipocytes.
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Affiliation(s)
- Minoru Ito
- Discovery Research Laboratories, Kyorin Pharmaceutical Co. Ltd., Tochigi 329-0114, Japan
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150
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Vigouroux C, Caron-Debarle M, Le Dour C, Magré J, Capeau J. Molecular mechanisms of human lipodystrophies: From adipocyte lipid droplet to oxidative stress and lipotoxicity. Int J Biochem Cell Biol 2011; 43:862-76. [DOI: 10.1016/j.biocel.2011.03.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 02/21/2011] [Accepted: 03/02/2011] [Indexed: 01/06/2023]
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