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Kang X, Wang Y, Liang W, Tang X, Zhang Y, Wang L, Zhao P, Lu Z. Bombyx mori nucleopolyhedrovirus downregulates transcription factor BmFoxO to elevate virus infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 116:103904. [PMID: 33245980 DOI: 10.1016/j.dci.2020.103904] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/16/2020] [Accepted: 10/18/2020] [Indexed: 06/11/2023]
Abstract
Forkhead-box O (FoxO) is the primary transcriptional effector of the insulin-like signaling pathway that enhances gluconeogenesis through transcriptional activation of PEPCK and G6Pase in mammals. We have previously demonstrated the involvement of phosphoenolpyruvate carboxykinase (BmPEPCK-2) in antiviral immunity against the multiplication of Bombyx mori nuclearpolyhedrosisvirus (BmNPV) in silkworm. Therefore, we speculated that BmFoxO might suppress BmNPV by regulating the expression of PEPCK in silkworm. In the present study, we found that the expression of BmFoxO decreased after BmNPV infection in Bombyx mori; this finding was consistent with BmPEPCK-2 expression. In addition, the expression of BmFoxO was altered, and it was found that reduced expression of BmFoxO (dsBmFoxO) downregulated the expression of BmPEPCK-2 and increased the viral fluorescence and content in silkworm embryonic cell line BmE cells, and vice versa. BmFoxO could upregulate the expression of BmPEPCK-2 by binding to the BmPEPCK-2 promoter. Moreover, overexpression of BmFoxO significantly increased the expression of autophagy genes ATG6/7/8 after infection with BmNPV, consistent with BmPEPCK-2. These results indicate that BmNPV downregulates transcription factor BmFoxO to elevate virus infection, and BmFoxO overexpression upregulates BmPEPCK-2 expression and enhances silkworm antiviral resistance.
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Affiliation(s)
- Xiaoli Kang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China
| | - Yaping Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China
| | - Wenjuan Liang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China
| | - Xin Tang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China
| | - Yan Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, PR China
| | - Lingyan Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, PR China
| | - Ping Zhao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, PR China
| | - Zhongyan Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, PR China; Biological Science Research Center, Southwest University, Chongqing, 400715, PR China; Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400715, PR China.
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Wang L, Guo Y, Pan M, Li X, Huang D, Liu Y, Wu C, Zhang W, Mai K. Functions of Forkhead Box O on Glucose Metabolism in Abalone Haliotis discus hannai and Its Responses to High Levels of Dietary Lipid. Genes (Basel) 2021; 12:genes12020297. [PMID: 33672704 PMCID: PMC7924355 DOI: 10.3390/genes12020297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/05/2021] [Accepted: 02/17/2021] [Indexed: 12/23/2022] Open
Abstract
The forkhead box O (FoxO) subfamily is a member of the forkhead transcription factor family. It has regulation functions in glucose metabolism in mammals and fish. In the present study, a gene of the foxo homolog in abalone Haliotis discus hannai was cloned. A conservative forkhead (FH) domain and a transactivation (FoxO-TAD) domain were identified. Abalone foxo-specific siRNA (small interfering RNA) was injected to investigate the functions of foxo on glucose metabolism. Knockdown of foxo inhibited expression of phosphoenolpyruvate carboxykinase (pepck) and significantly increased expressions of hexokinase (hk) and pyruvate kinase (pk), but it failed to inhibit the relative mRNA level of glucose-6-phosphatase (g6pase). Then, a 100-day feeding trial was conducted to investigate the response of foxo and glucose metabolism in abalone fed with 1.57% (LFD, low-fat diet), 3.82% (MFD, middle-fat diet) and 6.72% (HFD, high-fat diet) of dietary lipid, respectively. The insulin-signaling pathway (AKT) was depressed and FoxO was activated by the HFD, but it did not inhibit glycolysis (hk) or improved gluconeogenesis significantly (pepck and g6pase). At the same time, impaired hepatopancreas glycogen storage raised hemolymph glucose levels. In conclusion, abalone foxo can be regulated by dietary lipid and can regulate gluconeogenesis or glycolysis in response to changes of dietary lipid levels, in which glycogen metabolism plays an important role.
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Affiliation(s)
- Liu Wang
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
| | - Yanlin Guo
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
| | - Mingzhu Pan
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
| | - Xinxin Li
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
| | - Dong Huang
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
| | - Yue Liu
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
| | - Chenglong Wu
- School of Life Science, Huzhou University, 759 East 2nd Road, Huzhou 313000, China
- Correspondence: (C.W.); (W.Z.); Tel.: +86-532-8203-2145 (W.Z.)
| | - Wenbing Zhang
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
- Correspondence: (C.W.); (W.Z.); Tel.: +86-532-8203-2145 (W.Z.)
| | - Kangsen Mai
- The Key Laboratory of Aquaculture Nutrition and Feeds (Ministry of Agriculture and Rural Affairs), the Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao 266003, China; (L.W.); (Y.G.); (M.P.); (X.L.); (D.H.); (Y.L.); (K.M.)
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Mohammed ED, Abdel-Naim AB, Kangpeng J, Jiang R, Wei J, Sun B. The mother relationship between insulin resistance and non-alcoholic steatohepatitis: Glucosinolates hydrolysis products as a promising insulin resistance-modulator and fatty liver-preventer. Life Sci 2020; 264:118615. [PMID: 33096115 DOI: 10.1016/j.lfs.2020.118615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/09/2020] [Accepted: 10/14/2020] [Indexed: 11/25/2022]
Abstract
Non-alcoholic fatty liver disease (NFLD) is one of the present public health problems which have no specific and effective treatment. The speed of the disease progression depends on the patient's lifestyle. Due to life stresses and lack of time, a high number of people depend on fast food containing a high amount of fats which one of the main causes of insulin resistance (IR). IR is one of the metabolic disorders which strongly intersected with molecular NAFLD and leading to its progression into non-alcoholic steatohepatitis (NASH). In this review, we introduced the updated statistics of NAFLD and NASH progression all over the world shows its importance, etiologies, and pathogenesis. Also, IR and its role in NASH initiation and progression explored, and current treatments with its limitations have been explained. Glucosinolates (GLS) is a group of phytochemicals which known by its potent hydrolysis products with promising anti-cancer effect. In this review, we have collected the recent experimental studies of different GLS hydrolysis products against IR and chronic liver diseases supported by our lab finding. Finally, we recommend this group of phytochemicals as promising molecules to be studied experimentally and clinically against a wide range of chronic liver diseases with an acceptable safety margin.
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Affiliation(s)
- Eman D Mohammed
- Department of Clinical Pharmacology, Nanjing Drum Tower Hospital, Pharmacy Collage of Nanjing Medical University, Nanjing 210000, Jiangsu Province, China; Department of Hepatobiliary Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210093, Jiangsu Province, China; Natural Products Unit, Medicinal and Aromatic Plants Department, Desert Research Centre, Cairo, Egypt
| | - Ashraf B Abdel-Naim
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jin Kangpeng
- Department of Hepatobiliary Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210093, Jiangsu Province, China
| | - Runqiu Jiang
- Department of Hepatobiliary Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210093, Jiangsu Province, China
| | - Jifu Wei
- Research Division of Clinical Pharmacology, The First Affiliated Hospital, Pharmacy College of Nanjing Medical University, Nanjing 210000, Jiangsu Province, China
| | - Beicheng Sun
- Department of Hepatobiliary Surgery, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210093, Jiangsu Province, China; Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing 210000, Jiangsu Province, China.
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Liu YZ, Peng W, Chen JK, Su WJ, Yan WJ, Wang YX, Jiang CL. FoxO1 is a critical regulator of hepatocyte lipid deposition in chronic stress mice. PeerJ 2019; 7:e7668. [PMID: 31579588 PMCID: PMC6768057 DOI: 10.7717/peerj.7668] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/13/2019] [Indexed: 01/28/2023] Open
Abstract
Forkhead box O1 (FoxO1) is involved in lipid metabolisms. However, its role in chronic stress-related nonalcoholic fatty liver disease (NAFLD) is unclear. The scientific premise of our study was based on the finding that FoxO1 expression is increased in the liver of mice after chronic stress. It is important to understand the mechanisms involved in the activation of FoxO1 and how its function affects the liver lipid deposition. We employed a murine chronic stress model, in which mice were treated by plantar electrical stimulation and restraint for 6 weeks, and a cellular model, in which Hepa1–6 cells were treated with corticosterone. We also used a pharmacologic approach as1842856, a highly specific FoxO1 inhibitor. Lipid metabolism related genes levels were measured by qRT-PCR and the lipid levels by biochemical detection. We show that the level of FoxO1 is significantly elevated in the liver of chronic stress mice. Transcription factor FoxO1 regulates a lipid synthesis phenotype of hepatocyte that is involved in the development and progression of NAFLD. We have shown that inhibition of FoxO1 induced phenotypic conversion of hepatocytes and down-regulates lipid synthesis genes expression by hepatocytes, which contribute to lipid deposition in NAFLD. At the cellular level, the inhibitor of FoxO1 as1842856 can also attenuate the lipid deposition of Hepa1–6 cells induced by corticosterone. Targeting FoxO1 is a novel therapeutic target for chronic stress-related NAFLD.
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Affiliation(s)
- Yun-Zi Liu
- Department of Stress Medicine, Faculty of Psychology, Second Military Medical University, Shanghai, China
| | - Wei Peng
- Department of Stress Medicine, Faculty of Psychology, Second Military Medical University, Shanghai, China
| | - Ji-Kuai Chen
- Department of Health Toxicology, Faculty of Naval Medicine, Second Military Medical University, Shanghai, China
| | - Wen-Jun Su
- Department of Stress Medicine, Faculty of Psychology, Second Military Medical University, Shanghai, China
| | - Wen-Jie Yan
- Department of Stress Medicine, Faculty of Psychology, Second Military Medical University, Shanghai, China
| | - Yun-Xia Wang
- Department of Stress Medicine, Faculty of Psychology, Second Military Medical University, Shanghai, China
| | - Chun-Lei Jiang
- Department of Stress Medicine, Faculty of Psychology, Second Military Medical University, Shanghai, China
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Wu Y, Pan Q, Yan H, Zhang K, Guo X, Xu Z, Yang W, Qi Y, Guo CA, Hornsby C, Zhang L, Zhou A, Li L, Chen Y, Zhang W, Sun Y, Zheng H, Wondisford F, He L, Guo S. Novel Mechanism of Foxo1 Phosphorylation in Glucagon Signaling in Control of Glucose Homeostasis. Diabetes 2018; 67:2167-2182. [PMID: 30201683 PMCID: PMC6198346 DOI: 10.2337/db18-0674] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/21/2018] [Indexed: 12/19/2022]
Abstract
Dysregulation of hepatic glucose production (HGP) serves as a major underlying mechanism for the pathogenesis of type 2 diabetes. The pancreatic hormone glucagon increases and insulin suppresses HGP, controlling blood glucose homeostasis. The forkhead transcription factor Foxo1 promotes HGP through increasing expression of genes encoding the rate-limiting enzymes responsible for gluconeogenesis. We previously established that insulin suppresses Foxo1 by Akt-mediated phosphorylation of Foxo1 at Ser256 in human hepatocytes. In this study, we found a novel Foxo1 regulatory mechanism by glucagon, which promotes Foxo1 nuclear translocation and stability via cAMP- and protein kinase A-dependent phosphorylation of Foxo1 at Ser276 Replacing Foxo1-S276 with alanine (A) or aspartate (D) to block or mimic phosphorylation, respectively, markedly regulates Foxo1 stability and nuclear localization in human hepatocytes. To establish in vivo function of Foxo1-Ser276 phosphorylation in glucose metabolism, we generated Foxo1-S273A and Foxo1-S273D knock-in (KI) mice. The KI mice displayed impaired blood glucose homeostasis, as well as the basal and glucagon-mediated HGP in hepatocytes. Thus, Foxo1-Ser276 is a new target site identified in the control of Foxo1 bioactivity and associated metabolic diseases.
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Affiliation(s)
- Yuxin Wu
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Quan Pan
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Hui Yan
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Kebin Zhang
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Xiaoqin Guo
- Department of Endocrinology, Third Military Medical University, Chongqing, China
- Division of Endocrinology, Department of Medicine, Johns Hopkins University, Baltimore, MD
| | - Zihui Xu
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Wanbao Yang
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Yajuan Qi
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Cathy A Guo
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Caitlyn Hornsby
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Lin Zhang
- Department of Chemistry, Cleveland State University, Cleveland, OH
| | - Aimin Zhou
- Department of Chemistry, Cleveland State University, Cleveland, OH
| | - Ling Li
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Yunmei Chen
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Weiping Zhang
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Yuxiang Sun
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
| | - Hongting Zheng
- Department of Endocrinology, Third Military Medical University, Chongqing, China
| | - Fred Wondisford
- Division of Endocrinology, Department of Medicine, Johns Hopkins University, Baltimore, MD
| | - Ling He
- Division of Endocrinology, Department of Medicine, Johns Hopkins University, Baltimore, MD
| | - Shaodong Guo
- Department of Nutrition and Food Science, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX
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Schill D, Nord J, Cirillo LA. FoxO1 and FoxA1/2 form a complex on DNA and cooperate to open chromatin at insulin-regulated genes. Biochem Cell Biol 2018; 97:118-129. [PMID: 30142277 DOI: 10.1139/bcb-2018-0104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have previously shown that cooperative, interdependent binding by the pioneer factors FoxO1 and FoxA1/2 is required for recruitment of RNA polymerase II and H3K27 acetylation to the promoters of insulin-regulated genes. However, the underlying mechanisms are unknown. In this study, we demonstrate that, in HepG2 cells, FoxO1 and FoxA2 form a complex on DNA that is disrupted by insulin treatment. Insulin-mediated phosphorylation of FoxO1 and FoxA2 does not impair their cooperative binding to mononucleosome particles assembled from the IGFBP1 promoter, indicating that direct disruption of complex formation by phosphorylation is not responsible for the loss of interdependent FoxO1:FoxA1/2 binding following insulin treatment. Since FoxO1 and FoxA1/2 binding is required for the establishment and maintenance of transcriptionally active chromatin at insulin-regulated genes, we hypothesized that cooperative FoxO1 and FoxA1/2 binding dictates the chromatin remodeling events required for the initial activation of these genes. In support of this idea, we demonstrate that FoxO1 and FoxA2 cooperatively open linker histone compacted chromatin templates containing the IGFBP1 promoter. Taken together, these results provide a mechanism for how interdependent FoxO1:FoxA1/2 binding is negatively impacted by insulin and provide a developmental context for cooperative gene activation by these factors.
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Affiliation(s)
- Daniel Schill
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Joshua Nord
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Lisa Ann Cirillo
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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Yarushkin AA, Mazin ME, Yunusova AY, Korchagina KV, Pustylnyak YA, Prokopyeva EA, Pustylnyak VO. CAR-mediated repression of Cdkn1a(p21) is accompanied by the Akt activation. Biochem Biophys Res Commun 2018; 504:361-366. [PMID: 29890134 DOI: 10.1016/j.bbrc.2018.06.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/08/2018] [Indexed: 11/25/2022]
Abstract
It was shown that CAR participates in the regulation of many cell processes. Thus, the activation of CAR causes a proliferating effect in the liver, which provides grounds to consider CAR as a therapeutic target when having a partial resection of this organ. Even though a lot of work has been done on the function of CAR in regulating hepatocyte proliferation, very little has been done on its complex mediating mechanism. This study, therefore, showed that the liver growth resulting from CAR activation leads to the decline in the level of PTEN protein and subsequent Akt activation in mouse liver. The increase of Akt activation produced by CAR agonist was accompanied by a decrease in the level of Foxo1, which was correlated with decreased expression of Foxo1 target genes, including Cdkn1a(p21). Moreover, the study also demonstrated that there exists a negative regulatory impact of CAR on the relationship between Foxo1 and targeted Cdkn1a(p21) promoter. Therefore, the study results revealed an essential function of CAR-Akt-Foxo1 signalling pathway in controlling hepatocyte proliferation by repressing the cell cycle regulator Cdkn1a (p21).
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Affiliation(s)
- Andrei A Yarushkin
- Novosibirsk State University, Novosibirsk, Pirogova Street, 1, 630090, Russia; Federal Research Center of Fundamental and Translational Medicine, Novosibirsk, Timakova Street, 2/12, 630117, Russia
| | - Mark E Mazin
- Novosibirsk State University, Novosibirsk, Pirogova Street, 1, 630090, Russia
| | - Anastasia Y Yunusova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 8 Lavrentjev Avenue, 630090, Russia
| | - Kseniya V Korchagina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 8 Lavrentjev Avenue, 630090, Russia
| | - Yuliya A Pustylnyak
- Novosibirsk State University, Novosibirsk, Pirogova Street, 1, 630090, Russia
| | - Elena A Prokopyeva
- Novosibirsk State University, Novosibirsk, Pirogova Street, 1, 630090, Russia; Federal Research Center of Fundamental and Translational Medicine, Novosibirsk, Timakova Street, 2/12, 630117, Russia
| | - Vladimir O Pustylnyak
- Novosibirsk State University, Novosibirsk, Pirogova Street, 1, 630090, Russia; Federal Research Center of Fundamental and Translational Medicine, Novosibirsk, Timakova Street, 2/12, 630117, Russia.
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Unterman TG. Regulation of Hepatic Glucose Metabolism by FoxO Proteins, an Integrated Approach. Curr Top Dev Biol 2018; 127:119-147. [DOI: 10.1016/bs.ctdb.2017.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Shavva VS, Bogomolova AM, Nikitin AA, Dizhe EB, Oleinikova GN, Lapikov IA, Tanyanskiy DA, Perevozchikov AP, Orlov SV. FOXO1 and LXRα downregulate the apolipoprotein A-I gene expression during hydrogen peroxide-induced oxidative stress in HepG2 cells. Cell Stress Chaperones 2017; 22:123-134. [PMID: 27896567 PMCID: PMC5225066 DOI: 10.1007/s12192-016-0749-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/14/2016] [Accepted: 11/15/2016] [Indexed: 12/17/2022] Open
Abstract
Reactive oxygen species damage various cell components including DNA, proteins, and lipids, and these impairments could be a reason for severe human diseases including atherosclerosis. Forkhead box O1 (FOXO1), an important metabolic transcription factor, upregulates antioxidant and proapoptotic genes during oxidative stress. Apolipoprotein A-I (ApoA-I) forms high density lipoprotein (HDL) particles that are responsible for cholesterol transfer from peripheral tissues to liver for removal in bile in vertebrates. The main sources for plasma ApoA-I in mammals are liver and jejunum. Hepatic apoA-I transcription depends on a multitude of metabolic transcription factors. We demonstrate that ApoA-I synthesis and secretion are decreased during H2O2-induced oxidative stress in human hepatoma cell line HepG2. Here, we first show that FOXO1 binds to site B of apoA-I hepatic enhancer and downregulates apoA-I gene activity in HepG2 cells. Moreover, FOXO1 and LXRα transcription factors participate in H2O2-triggered downregulation of apoA-I gene together with Src, JNK, p38, and AMPK kinase cascades. Mutations of sites B or C as well as the administration of siRNAs against FOXO1 or LXRα to HepG2 cells abolished the hydrogen peroxide-mediated suppression of apoA-I gene.
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Affiliation(s)
- Vladimir S Shavva
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia.
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
| | | | - Artemy A Nikitin
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia
- Department of Biochemistry, St. Petersburg State University, St. Petersburg, Russia
| | - Ella B Dizhe
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia
| | - Galina N Oleinikova
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia
| | - Ivan A Lapikov
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Dmitry A Tanyanskiy
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia
- Department of Fundamental Medicine and Medical Technologies, St. Petersburg State University, St. Petersburg, Russia
| | - Andrej P Perevozchikov
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Sergey V Orlov
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, Acad. Pavlov St., 12, St. Petersburg, 197376, Russia.
- Department of Embryology, St. Petersburg State University, St. Petersburg, Russia.
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Shavva VS, Bogomolova AM, Nikitin AA, Dizhe EB, Tanyanskiy DA, Efremov AM, Oleinikova GN, Perevozchikov AP, Orlov SV. Insulin-Mediated Downregulation of Apolipoprotein A-I Gene in Human Hepatoma Cell Line HepG2: The Role of Interaction Between FOXO1 and LXRβ Transcription Factors. J Cell Biochem 2016; 118:382-396. [PMID: 27404023 DOI: 10.1002/jcb.25651] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 07/11/2016] [Indexed: 12/22/2022]
Abstract
Apolipoprotein A-I (ApoA-I) is a key component of high density lipoproteins which possess anti-atherosclerotic and anti-inflammatory properties. Insulin is a crucial mediator of the glucose and lipid metabolism that has been implicated in atherosclerotic and inflammatory processes. Important mediators of insulin signaling such as Liver X Receptors (LXRs) and Forkhead Box A2 (FOXA2) are known to regulate apoA-I expression in liver. Forkhead Box O1 (FOXO1) is a well-known target of insulin signaling and a key mediator of oxidative stress response. Low doses of insulin were shown to activate apoA-I expression in human hepatoma HepG2 cells. However, the detailed mechanisms for these processes are still unknown. We studied the possible involvement of FOXO1, FOXA2, LXRα, and LXRβ transcription factors in the insulin-mediated regulation of apoA-I expression. Treatment of HepG2 cells with high doses of insulin (48 h, 100 nM) suppresses apoA-I gene expression. siRNAs against FOXO1, FOXA2, LXRβ, or LXRα abrogated this effect. FOXO1 forms a complex with LXRβ and insulin treatment impairs FOXO1/LXRβ complex binding to hepatic enhancer and triggers its nuclear export. Insulin as well as LXR ligand TO901317 enhance the interaction between FOXA2, LXRα, and hepatic enhancer. These data suggest that high doses of insulin downregulate apoA-I gene expression in HepG2 cells through redistribution of FOXO1/LXRβ complex, FOXA2, and LXRα on hepatic enhancer of apoA-I gene. J. Cell. Biochem. 118: 382-396, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Vladimir S Shavva
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.,Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | | | - Artemy A Nikitin
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.,Department of Biochemistry, St. Petersburg State University, St. Petersburg, Russia
| | - Ella B Dizhe
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
| | - Dmitry A Tanyanskiy
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.,Department of Fundamental Medicine and Medical Technologies, St. Petersburg State University, St. Petersburg, Russia
| | - Alexander M Efremov
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.,Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Galina N Oleinikova
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia
| | - Andrej P Perevozchikov
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.,Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
| | - Sergey V Orlov
- Department of Biochemistry, Institute of Experimental Medicine, Russian Academy of Medical Sciences, St. Petersburg, Russia.,Department of Embryology, St. Petersburg State University, St. Petersburg, Russia
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11
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Pandey G, Shankar K, Makhija E, Gaikwad A, Ecelbarger C, Mandhani A, Srivastava A, Tiwari S. Reduced Insulin Receptor Expression Enhances Proximal Tubule Gluconeogenesis. J Cell Biochem 2016; 118:276-285. [PMID: 27322100 DOI: 10.1002/jcb.25632] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 06/16/2016] [Indexed: 12/18/2022]
Abstract
Reduced insulin receptor protein levels have been reported in the kidney cortex from diabetic humans and animals. We recently reported that, targeted deletion of insulin receptor (IR) from proximal tubules (PT) resulted in hyperglycemia in non-obese mice. To elucidate the mechanism, we examined human proximal tubule cells (hPTC) and C57BL/6 mice fed with high-fat diet (HFD, 60% fat for 20 weeks). Immunoblotting revealed a significantly lower protein level of IR in HFD compare to normal chow diet (NCD). Furthermore, a blunted rise in p-AKT308 levels in the kidney cortex of HFD mice was observed in response to acute insulin (0.75 IU/kg body weight, i.p) relative to NCD n = 8/group, P < 0.05). Moreover, we found significantly higher transcript levels of phosphoenolpyruvate carboxykinase (PEPCK, a key gluconeogenic enzyme) in the kidney cortex from HFD, relative to mice on NCD. The higher level of PEPCK in HFD was confirmed by immunoblotting. However, no significant differences were observed in cortical glucose-6-phosphatase (G6Pase) or fructose-1,6, bisphosphosphatase (FBPase) enzyme transcript levels. Furthermore, we demonstrated insulin inhibited glucose production in hPTC treated with cyclic AMP and dexamethasone (cAMP/DEXA) to stimulate gluconeogenesis. Transcript levels of the gluconeogenic enzyme PEPCK were significantly increased in cAMP/DEXA-stimulated hPTC cells (n = 3, P < 0.05), and insulin attenuated this upregulation Furthermore, the effect of insulin on cAMP/DEXA-induced gluconeogenesis and PEPCK induction was significantly attenuated in IR (siRNA) silenced hPTC (n = 3, P < 0.05). Overall the above data indicate a direct role for IR expression as a determinant of PT-gluconeogenesis. Thus reduced insulin signaling of the proximal tubule may contribute to hyperglycemia in the metabolic syndrome via elevated gluconeogenesis. J. Cell. Biochem. 118: 276-285, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Gaurav Pandey
- Department of Molecular Medicine and Biotechnology, SGPGIMS, Lucknow, 226014, India
| | | | - Ekta Makhija
- Department of Molecular Medicine and Biotechnology, SGPGIMS, Lucknow, 226014, India
| | | | - Carolyn Ecelbarger
- Department of Medicine, Georgetown University, Washington, District of Columbia
| | | | | | - Swasti Tiwari
- Department of Molecular Medicine and Biotechnology, SGPGIMS, Lucknow, 226014, India.,Department of Medicine, Georgetown University, Washington, District of Columbia
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12
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Zhang W, Bu SY, Mashek MT, O-Sullivan I, Sibai Z, Khan SA, Ilkayeva O, Newgard CB, Mashek DG, Unterman TG. Integrated Regulation of Hepatic Lipid and Glucose Metabolism by Adipose Triacylglycerol Lipase and FoxO Proteins. Cell Rep 2016; 15:349-59. [PMID: 27050511 DOI: 10.1016/j.celrep.2016.03.021] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 02/23/2016] [Accepted: 03/03/2016] [Indexed: 12/16/2022] Open
Abstract
Metabolism is a highly integrated process that is coordinately regulated between tissues and within individual cells. FoxO proteins are major targets of insulin action and contribute to the regulation of gluconeogenesis, glycolysis, and lipogenesis in the liver. However, the mechanisms by which FoxO proteins exert these diverse effects in an integrated fashion remain poorly understood. We report that FoxO proteins also exert important effects on intrahepatic lipolysis and fatty acid oxidation via the regulation of adipose triacylglycerol lipase (ATGL), which mediates the first step in lipolysis, and its inhibitor, the G0/S1 switch 2 gene (G0S2). We also find that ATGL-dependent lipolysis plays a critical role in mediating diverse effects of FoxO proteins in the liver, including effects on gluconeogenic, glycolytic, and lipogenic gene expression and metabolism. These results indicate that intrahepatic lipolysis plays a critical role in mediating and integrating the regulation of glucose and lipid metabolism downstream of FoxO proteins.
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Affiliation(s)
- Wenwei Zhang
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - So Young Bu
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Mara T Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - InSug O-Sullivan
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - Zakaria Sibai
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA
| | - Salmaan A Khan
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
| | - Olga Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University, Durham, NC 27710, USA; Department of Pharmacology, Duke University, Durham, NC 27710, USA; Department of Medicine, Duke University, Durham, NC 27710, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University, Durham, NC 27710, USA; Department of Pharmacology, Duke University, Durham, NC 27710, USA; Department of Medicine, Duke University, Durham, NC 27710, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Terry G Unterman
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; Medical Research Service, Jesse Brown VA Medical Center, Chicago, IL 60612, USA.
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13
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Yalley A, Schill D, Hatta M, Johnson N, Cirillo LA. Loss of Interdependent Binding by the FoxO1 and FoxA1/A2 Forkhead Transcription Factors Culminates in Perturbation of Active Chromatin Marks and Binding of Transcriptional Regulators at Insulin-sensitive Genes. J Biol Chem 2016; 291:8848-61. [PMID: 26929406 DOI: 10.1074/jbc.m115.677583] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Indexed: 01/04/2023] Open
Abstract
FoxO1 binds to insulin response elements located in the promoters of insulin-like growth factor-binding protein 1 (IGFBP1) and glucose-6-phosphatase (G6Pase), activating their expression. Insulin-mediated phosphorylation of FoxO1 promotes cytoplasmic translocation, inhibiting FoxO1-mediated transactivation. We have previously demonstrated that FoxO1 opens and remodels chromatin assembled from the IGFBP1 promoter via a highly conserved winged helix motif. This finding, which established FoxO1 as a "pioneer" factor, suggested a model whereby FoxO1 chromatin remodeling at regulatory targets facilitates binding and recruitment of additional regulatory factors. However, the impact of FoxO1 phosphorylation on its ability to bind chromatin and the effect of FoxO1 loss on recruitment of neighboring transcription factors at its regulatory targets in liver chromatin is unknown. In this study, we demonstrate that an amino acid substitution that mimics insulin-mediated phosphorylation of a serine in the winged helix DNA binding motif curtails FoxO1 nucleosome binding. We also demonstrate that shRNA-mediated loss of FoxO1 binding to the IGFBP1 and G6Pase promoters in HepG2 cells significantly reduces binding of RNA polymerase II and the pioneer factors FoxA1/A2. Knockdown of FoxA1 similarly reduced binding of RNA polymerase II and FoxO1. Reduction in acetylation of histone H3 Lys-27 accompanies loss of FoxO1 and FoxA1/A2 binding. Interdependent binding of FoxO1 and FoxA1/A2 possibly entails cooperative binding because FoxO1 and FoxA1/A2 facilitate one another's binding to IGFPB1 promoter DNA. These results illustrate how transcription factors can nucleate transcriptional events in chromatin in response to signaling events and suggest a model for regulation of hepatic glucose metabolism through interdependent FoxO/FoxA binding.
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Affiliation(s)
- Akua Yalley
- From the Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Daniel Schill
- From the Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Mitsutoki Hatta
- From the Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Nicole Johnson
- From the Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Lisa Ann Cirillo
- From the Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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14
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Camer D, Yu Y, Szabo A, Dinh CHL, Wang H, Cheng L, Huang XF. Bardoxolone methyl prevents insulin resistance and the development of hepatic steatosis in mice fed a high-fat diet. Mol Cell Endocrinol 2015; 412:36-43. [PMID: 26001833 DOI: 10.1016/j.mce.2015.05.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 04/27/2015] [Accepted: 05/15/2015] [Indexed: 02/07/2023]
Abstract
High-fat (HF) diet-induced obesity is a major risk factor for the development of insulin resistance and hepatic steatosis. We examined the hypothesis that bardoxolone methyl (BM) would prevent the development of insulin resistance and hepatic steatosis in mice fed a HF diet. C57BL/6J male mice were fed a lab chow (LC), HF (40% fat), or HF diet supplemented with 10 mg/kg/day BM orally for 21 weeks. Glucose metabolism was assessed using a glucose tolerance test (GTT) and insulin sensitivity test (IST). Signalling molecules involved in insulin resistance, inflammation, and lipid metabolism were examined in liver tissue via western blotting and RT-PCR. BM prevented HF diet-induced insulin resistance and alterations in the protein levels of protein tyrosine phosphatase 1B (PTP1B), forkhead box protein O1 (FOXO1) and BDNF, and expression of the insulin receptor (IR), IRS-1 and glucose-6-phosphatase (G6Pase) genes. Furthermore, BM prevented fat accumulation in the liver and decreases in the β-oxidation gene, peroxisomal acyl-coenzyme A oxidase 1 (ACOX) in mice fed a HF diet. In the livers of HF fed mice, BM administration prevented HF diet-induced macrophage infiltration, inflammation as indicated by reduced IL-6 and signal transducer and activator of transcription 3 (STAT3) protein levels and TNFα mRNA expression, and increased nuclear factor-like 2 (Nrf2) mRNA expression and nuclear protein levels. These findings suggest that BM prevents HF diet induced insulin resistance and the development of hepatic steatosis in mice fed a chronic HF diet through modulation of molecules involved in insulin signalling, lipid metabolism and inflammation in the liver.
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Affiliation(s)
- Danielle Camer
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia
| | - Yinghua Yu
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia
| | - Alexander Szabo
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia; ANSTO LifeSciences, Australian Nuclear Science and Technology Organisation, NSW 2234, Australia
| | - Chi H L Dinh
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia
| | - Hongqin Wang
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia
| | - Licai Cheng
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia
| | - Xu-Feng Huang
- Centre for Translational Neuroscience, Faculty of Science, Medicine and Health and Illawarra Health and Medical Research Institute, University of Wollongong, NSW 2522, Australia.
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15
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Turkmen K, Karagoz A, Kucuk A. Sirtuins as novel players in the pathogenesis of diabetes mellitus. World J Diabetes 2014; 5:894-900. [PMID: 25512793 PMCID: PMC4265877 DOI: 10.4239/wjd.v5.i6.894] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/04/2014] [Accepted: 10/10/2014] [Indexed: 02/05/2023] Open
Abstract
Diabetes mellitus (DM) is a systemic and complex disease with micro and macrovascular complications that result from impaired metabolic pathways and genetic susceptibilities. DM has been accepted as an epidemic worldwide during the last two decades. A substantial gap in our knowledge exists regarding the pathophysiology of this metabolic disorder despite the improved diagnostic tools and therapeutic approaches. Sirtuins are a group of NAD+ dependent enzymes that are involved in cellular homeostasis due to their deacetylating activity. In the present review, we aimed to discuss the role of associated sirtuins in the pathogenesis and treatment of diabetes mellitus.
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16
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Banerjee M, Robbins D, Chen T. Targeting xenobiotic receptors PXR and CAR in human diseases. Drug Discov Today 2014; 20:618-28. [PMID: 25463033 DOI: 10.1016/j.drudis.2014.11.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 10/28/2014] [Accepted: 11/17/2014] [Indexed: 12/20/2022]
Abstract
Nuclear receptors such as the pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are xenobiotic receptors regulating not only drug metabolism and disposition but also various human diseases such as cancer, diabetes, inflammatory disease, metabolic disease and liver diseases, suggesting that PXR and CAR are promising targets for drug discovery. Consequently, there is an urgent need to discover and develop small molecules that target these PXR- and/or CAR-mediated human-disease-related pathways for relevant therapeutic applications. This review proposes approaches to target PXR and CAR, either individually or simultaneously, in the context of various human diseases, taking into consideration the structural differences between PXR and CAR.
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Affiliation(s)
- Monimoy Banerjee
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Delira Robbins
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
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17
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Quiñones M, Al-Massadi O, Fernø J, Nogueiras R. Cross-talk between SIRT1 and endocrine factors: effects on energy homeostasis. Mol Cell Endocrinol 2014; 397:42-50. [PMID: 25109279 DOI: 10.1016/j.mce.2014.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 12/14/2022]
Abstract
The mammalian sirtuins (SIRT1-7) are a family of highly conserved nicotine adenine dinucleotide (NAD(+))-dependent deacetylases that act as cellular sensors to detect energy availability. SIRT1 is a multifaceted protein that is involved in a wide variety of cellular processes. SIRT1 is activated in response to caloric restriction, acting on multiple targets in a wide range of tissues. SIRT1 regulates the role of multiple hormones implicated in energy balance, including glucose and lipid metabolism. Here, we review the relevant role of SIRT1 as a mediator of endocrine function of several hormones to modulate energy balance. In addition, we analyze the potential of targeting SIRT1 for the treatment of obesity and type 2 diabetes mellitus.
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Affiliation(s)
- Mar Quiñones
- Department of Physiology, School of Medicine-CIMUS, Instituto de Investigacion Sanitaria (IDIS), CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), University of Santiago de Compostela, San Francisco s/n, Santiago de Compostela (A Coruña), 15782, and Avda. Barcelona 3, 15782, Santiago de Compostela, Spain.
| | - Omar Al-Massadi
- Department of Physiology, School of Medicine-CIMUS, Instituto de Investigacion Sanitaria (IDIS), CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), University of Santiago de Compostela, San Francisco s/n, Santiago de Compostela (A Coruña), 15782, and Avda. Barcelona 3, 15782, Santiago de Compostela, Spain
| | - Johan Fernø
- Department of Clinical Science, K. G. Jebsen Center for Diabetes Research, University of Bergen, Bergen, Norway
| | - Ruben Nogueiras
- Department of Physiology, School of Medicine-CIMUS, Instituto de Investigacion Sanitaria (IDIS), CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), University of Santiago de Compostela, San Francisco s/n, Santiago de Compostela (A Coruña), 15782, and Avda. Barcelona 3, 15782, Santiago de Compostela, Spain.
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18
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Kazantseva YA, Yarushkin AA, Pustylnyak VO. CAR-mediated repression of Foxo1 transcriptional activity regulates the cell cycle inhibitor p21 in mouse livers. Toxicology 2014; 321:73-9. [PMID: 24769335 DOI: 10.1016/j.tox.2014.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/14/2014] [Accepted: 04/15/2014] [Indexed: 01/29/2023]
Abstract
1,4-Bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP), an agonist of constitutive androstane receptor (CAR), is a well-known strong primary chemical mitogen for the mouse liver. Despite extensive investigation of the role of CAR in the regulation of cell proliferation, our knowledge of the intricate mediating mechanism is incomplete. In this study, we demonstrated that long-term CAR activation by TCPOBOP increased liver-to-body weight ratio and decreased tumour suppressor Foxo1 expression and transcriptional activity, which were correlated with reduced expression of genes regulated by Foxo1, including the cell-cycle inhibitor Cdkn1a(p21), and upregulation of the cell-cycle regulator Cyclin D1. Moreover, we demonstrated the negative regulatory effect of TCPOBOP-activated CAR on the association of Foxo1 with the target Foxo1 itself and Cdkn1a(p21) promoters. Thus, we identified CAR-mediated repression of cell cycle inhibitor p21, as mediated by repression of FOXO1 expression and transcriptional activity. CAR-FOXO1 cross-talk may provide new opportunities for understanding liver diseases and developing more effective therapeutic approaches to better drug treatments.
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Affiliation(s)
- Yuliya A Kazantseva
- Institute of Molecular Biology and Biophysics SB RAMS, Timakova str. 2, Novosibirsk 630117, Russia
| | - Andrei A Yarushkin
- Institute of Molecular Biology and Biophysics SB RAMS, Timakova str. 2, Novosibirsk 630117, Russia
| | - Vladimir O Pustylnyak
- Institute of Molecular Biology and Biophysics SB RAMS, Timakova str. 2, Novosibirsk 630117, Russia; Novosibirsk State University, Pirogova str. 2, Novosibirsk 630090, Russia.
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Guo S. Insulin signaling, resistance, and the metabolic syndrome: insights from mouse models into disease mechanisms. J Endocrinol 2014; 220:T1-T23. [PMID: 24281010 PMCID: PMC4087161 DOI: 10.1530/joe-13-0327] [Citation(s) in RCA: 326] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Insulin resistance is a major underlying mechanism responsible for the 'metabolic syndrome', which is also known as insulin resistance syndrome. The incidence of the metabolic syndrome is increasing at an alarming rate, becoming a major public and clinical problem worldwide. The metabolic syndrome is represented by a group of interrelated disorders, including obesity, hyperglycemia, hyperlipidemia, and hypertension. It is also a significant risk factor for cardiovascular disease and increased morbidity and mortality. Animal studies have demonstrated that insulin and its signaling cascade normally control cell growth, metabolism, and survival through the activation of MAPKs and activation of phosphatidylinositide-3-kinase (PI3K), in which the activation of PI3K associated with insulin receptor substrate 1 (IRS1) and IRS2 and subsequent Akt→Foxo1 phosphorylation cascade has a central role in the control of nutrient homeostasis and organ survival. The inactivation of Akt and activation of Foxo1, through the suppression IRS1 and IRS2 in different organs following hyperinsulinemia, metabolic inflammation, and overnutrition, may act as the underlying mechanisms for the metabolic syndrome in humans. Targeting the IRS→Akt→Foxo1 signaling cascade will probably provide a strategy for therapeutic intervention in the treatment of type 2 diabetes and its complications. This review discusses the basis of insulin signaling, insulin resistance in different mouse models, and how a deficiency of insulin signaling components in different organs contributes to the features of the metabolic syndrome. Emphasis is placed on the role of IRS1, IRS2, and associated signaling pathways that are coupled to Akt and the forkhead/winged helix transcription factor Foxo1.
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Affiliation(s)
- Shaodong Guo
- Division of Molecular Cardiology, Department of Medicine, College of Medicine, Texas A&M University Health Science Center, Scott & White, Central Texas Veterans Health Care System, 1901 South 1st Street, Bldg. 205, Temple, Texas 76504, USA
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20
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Zhao Y, Yu Y, Tian X, Yang X, Li X, Jiang F, Chen Y, Shi M. Association study to evaluate FoxO1 and FoxO3 gene in CHD in Han Chinese. PLoS One 2014; 9:e86252. [PMID: 24489705 PMCID: PMC3904908 DOI: 10.1371/journal.pone.0086252] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 12/10/2013] [Indexed: 12/22/2022] Open
Abstract
Background Coronary heart disease (CHD) is one of the leading causes of mortality and morbidity in China. Genetic factors that predispose individuals to CHD are unclear. In the present study, we aimed to determine whether the variation of FoxOs, a novel genetic factor associated with longevity, was associated with CHD in Han Chinese populations. Methods 1271 CHD patients and 1287 age-and sex-matched controls from Beijing and Harbin were included. We selected four tagging single nucleotide polymorphisms (SNPs) of FoxO1 (rs2755209, rs2721072, rs4325427 and rs17592371) and two tagging SNPs of FoxO3 (rs768023 and rs1268165). And the genotypes of these SNPs were determined in both CHD patients and non-CHD controls. Results For population from Beijing, four SNPs of FoxO1 and two SNPs of FoxO3 were found not to be associated with CHD (p>0.05). And this was validated in the other population from Harbin (p>0.05). After combining the two geographically isolated case-control populations, the results showed that the six SNPs did not necessarily predispose to CHD in Han Chinese(p>0.05). In stratified analysis according to gender, the history of smoking, hypertension, diabetes mellitus, hyperlipidemia and the metabolic syndrome, we further explored that neither the variants of FoxO1 nor the variants of FoxO3 might be associated with CHD (p>0.05). Conclusion The variants of FoxO1 and FoxO3 may not increase the prevalence of CHD in Han Chinese population.
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Affiliation(s)
- Ying Zhao
- Department of Geriatrics, Jinan Military General Hospital, Jinan, China
| | - Yanbo Yu
- Department of Gastroenterology, Qilu Hospital of Shandong University, Jinan, China
| | - Xiaoli Tian
- Department of Human Population Genetics, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Xi Yang
- Department of Human Population Genetics, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Xueqi Li
- Department of Cardiology, the Fourth Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Feng Jiang
- Department of Cardiology, the Fourth Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yundai Chen
- Department of Cardiology, Chinese PLA General Hospital, Beijing, China
- * E-mail: (YC); (MS)
| | - Maowei Shi
- Department of Geriatrics, Jinan Military General Hospital, Jinan, China
- * E-mail: (YC); (MS)
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22
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Brooks NC, Marshall AH, Qa'aty N, Hiyama Y, Boehning D, Jeschke MG. XBP-1s is linked to suppressed gluconeogenesis in the Ebb phase of burn injury. Mol Med 2013; 19:72-8. [PMID: 23508570 DOI: 10.2119/molmed.2012.00348] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/14/2013] [Indexed: 02/03/2023] Open
Abstract
The first 24 h following burn injury is known as the ebb phase and is characterized by a depressed metabolic rate. While the postburn ebb phase has been well described, the molecular mechanisms underlying this response are poorly understood. The endoplasmic reticulum (ER) regulates metabolic rate by maintaining glucose homeostasis through the hepatic ER stress response. We have shown that burn injury leads to ER stress in the liver during the first 24 h following thermal injury. However, whether ER stress is linked to the metabolic responses during the ebb phase of burn injury is poorly understood. Here, we show in an animal model that burn induces activation of activating transcription factor 6 (ATF6) and inositol requiring enzyme-1 (IRE-1) and this leads to increased expression of spliced X-box binding protein-1 (XBP-1s) messenger ribonucleic acid (mRNA) during the ebb phase. This is associated with increased expression of XBP-1 target genes and downregulation of the key gluconeogenic enzyme glucose-6-phosphatase (G6Pase). We conclude that upregulation of the ER stress response after burn injury is linked to attenuated gluconeogenesis and sustained glucose tolerance in the postburn ebb phase.
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Affiliation(s)
- Natasha C Brooks
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
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23
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Nogueiras R, Habegger KM, Chaudhary N, Finan B, Banks AS, Dietrich MO, Horvath TL, Sinclair DA, Pfluger PT, Tschöp MH. Sirtuin 1 and sirtuin 3: physiological modulators of metabolism. Physiol Rev 2012; 92:1479-514. [PMID: 22811431 DOI: 10.1152/physrev.00022.2011] [Citation(s) in RCA: 496] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The sirtuins are a family of highly conserved NAD(+)-dependent deacetylases that act as cellular sensors to detect energy availability and modulate metabolic processes. Two sirtuins that are central to the control of metabolic processes are mammalian sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3), which are localized to the nucleus and mitochondria, respectively. Both are activated by high NAD(+) levels, a condition caused by low cellular energy status. By deacetylating a variety of proteins that induce catabolic processes while inhibiting anabolic processes, SIRT1 and SIRT3 coordinately increase cellular energy stores and ultimately maintain cellular energy homeostasis. Defects in the pathways controlled by SIRT1 and SIRT3 are known to result in various metabolic disorders. Consequently, activation of sirtuins by genetic or pharmacological means can elicit multiple metabolic benefits that protect mice from diet-induced obesity, type 2 diabetes, and nonalcoholic fatty liver disease.
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Affiliation(s)
- Ruben Nogueiras
- Department of Physiology, School of Medicine-Instituto de Investigaciones Sanitarias, University of Santiago de Compostela, Santiago de Compostela, Spain
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24
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Zhang K, Li L, Qi Y, Zhu X, Gan B, DePinho RA, Averitt T, Guo S. Hepatic suppression of Foxo1 and Foxo3 causes hypoglycemia and hyperlipidemia in mice. Endocrinology 2012; 153:631-46. [PMID: 22147007 PMCID: PMC5393302 DOI: 10.1210/en.2011-1527] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dysregulation of blood glucose and triglycerides are the major characteristics of type 2 diabetes mellitus. We sought to identify the mechanisms regulating blood glucose and lipid homeostasis. Cell-based studies established that the Foxo forkhead transcription factors Forkhead box O (Foxo)-1, Foxo3, and Foxo4 are inactivated by insulin via a phosphatidylinositol 3-kinase/Akt-dependent pathway, but the role of Foxo transcription factors in the liver in regulating nutrient metabolism is incompletely understood. In this study, we used the Cre/LoxP genetic approach to delete the Foxo1, Foxo3, and Foxo4 genes individually or a combination of two or all in the liver of lean or db/db mice and assessed the role of Foxo inactivation in regulating glucose and lipid homeostasis in vivo. In the lean mice or db/db mice, hepatic deletion of Foxo1, rather than Foxo3 or Foxo4, caused a modest reduction in blood glucose concentrations and barely affected lipid homeostasis. Combined deletion of Foxo1 and Foxo3 decreased blood glucose levels, elevated serum triglyceride and cholesterol concentrations, and increased hepatic lipid secretion and caused hepatosteatosis. Analysis of the liver transcripts established a prominent role of Foxo1 in regulating gene expression of gluconeogenic enzymes and Foxo3 in the expression of lipogenic enzymes. Our findings indicate that Foxo1 and Foxo3 inactivation serves as a potential mechanism by which insulin reduces hepatic glucose production and increases hepatic lipid synthesis and secretion in healthy and diabetic states.
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Affiliation(s)
- Kebin Zhang
- Division of Molecular Cardiology, Cardiovascular Research Institute, College of Medicine, Texas A&M Health Science Center, Central Texas Veterans Health Care System, Temple, Texas 76504, USA
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25
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Nair AK, Sugunan D, Kumar H, Anilkumar G. Association analysis of common variants in FOXO3 with type 2 diabetes in a South Indian Dravidian population. Gene 2011; 491:182-6. [PMID: 22015955 DOI: 10.1016/j.gene.2011.09.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2011] [Revised: 09/25/2011] [Accepted: 09/29/2011] [Indexed: 12/01/2022]
Abstract
Recent studies have identified common variants in forkhead box O3 gene (FOXO3) to be strongly associated with longevity in different populations. But studies have not been carried out to analyse the role of common variants in FOXO3 with type 2 diabetes. Since type 2 diabetes is an age related disorder and FOXO proteins play an important role in the regulation of metabolism, we studied the role of common variants in FOXO3 for association with type 2 diabetes. The study was carried out in 994 type 2 diabetic samples and 984 normoglycemic control samples from a South Indian Dravidian population. In our analysis, we found that there was no association between any of the selected SNPs in FOXO3 with type 2 diabetes. Analysis of these SNPs with diabetes related biochemical and clinical parameters also did not reveal any significant association. Haplotype association of SNPs in FOXO3 with type 2 diabetes was observed, but the frequency of the haplotypes was considerably lower and they do not remain significant after correction for multiple testing. In conclusion, we did not observe any association of SNPs in FOXO3 with type 2 diabetes and related parameters suggesting an entirely different mechanism by which these SNPs influence longevity. However additional studies in other populations are required to completely rule out the association of common variants in FOXO3 with type 2 diabetes.
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Affiliation(s)
- Anup Kumar Nair
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri P.O., Kollam, Kerala, 690 525, India
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26
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Okamoto MM, Anhê GF, Sabino-Silva R, Marques MFDSF, Freitas HS, Mori RCT, Melo KFS, Machado UF. Intensive insulin treatment induces insulin resistance in diabetic rats by impairing glucose metabolism-related mechanisms in muscle and liver. J Endocrinol 2011; 211:55-64. [PMID: 21746792 DOI: 10.1530/joe-11-0105] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Insulin replacement is the only effective therapy to manage hyperglycemia in type 1 diabetes mellitus (T1DM). Nevertheless, intensive insulin therapy has inadvertently led to insulin resistance. This study investigates mechanisms involved in the insulin resistance induced by hyperinsulinization. Wistar rats were rendered diabetic by alloxan injection, and 2 weeks later received saline or different doses of neutral protamine Hagedorn insulin (1.5, 3, 6, and 9 U/day) over 7 days. Insulinopenic-untreated rats and 6U- and 9U-treated rats developed insulin resistance, whereas 3U-treated rats revealed the highest grade of insulin sensitivity, but did not achieve good glycemic control as 6U- and 9U-treated rats did. This insulin sensitivity profile was in agreement with glucose transporter 4 expression and translocation in skeletal muscle, and insulin signaling, phosphoenolpyruvate carboxykinase/glucose-6-phosphatase expression and glycogen storage in the liver. Under the expectation that insulin resistance develops in hyperinsulinized diabetic patients, we believe insulin sensitizer approaches should be considered in treating T1DM.
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Affiliation(s)
- Maristela Mitiko Okamoto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Avenida Prof. Lineu Prestes, 1524, 05505-900 São Paulo (SP), Brazil.
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27
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Luque RM, Gahete MD, Cordoba-Chacon J, Childs GV, Kineman RD. Does the pituitary somatotrope play a primary role in regulating GH output in metabolic extremes? Ann N Y Acad Sci 2011; 1220:82-92. [PMID: 21388406 DOI: 10.1111/j.1749-6632.2010.05913.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Circulating growth hormone (GH) levels rise in response to nutrient deprivation and fall in states of nutrient excess. Because GH regulates carbohydrate, lipid, and protein metabolism, defining the mechanisms by which changes in metabolism alter GH secretion will aid in our understanding of the cause, progression, and treatment of metabolic diseases. This review will summarize what is currently known regarding the impact of systemic metabolic signals on GH-axis function. In addition, ongoing studies using the Cre/loxP system to generate mouse models with selective somatotrope resistance to metabolic signals will be discussed, where these models will serve to enhance our understanding of the specific role the somatotrope plays in sensing the metabolic environment and adjusting GH output in metabolic extremes.
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Affiliation(s)
- Raul M Luque
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba, CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain
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28
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Nogueira TC, Lellis-Santos C, Jesus DS, Taneda M, Rodrigues SC, Amaral FG, Lopes AMS, Cipolla-Neto J, Bordin S, Anhê GF. Absence of melatonin induces night-time hepatic insulin resistance and increased gluconeogenesis due to stimulation of nocturnal unfolded protein response. Endocrinology 2011; 152:1253-63. [PMID: 21303940 DOI: 10.1210/en.2010-1088] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It is known that the circadian rhythm in hepatic phosphoenolpyruvate carboxykinase expression (a limiting catalytic step of gluconeogenesis) and hepatic glucose production is maintained by both daily oscillation in autonomic inputs to the liver and night feeding behavior. However, increased glycemia and reduced melatonin (Mel) levels have been recently shown to coexist in diabetic patients at the end of the night period. In parallel, pinealectomy (PINX) is known to cause glucose intolerance with increased basal glycemia exclusively at the end of the night. The mechanisms that underlie this metabolic feature are not completely understood. Here, we demonstrate that PINX rats show night-time hepatic insulin resistance characterized by reduced insulin-stimulated RAC-α serine/threonine-protein kinase phosphorylation and increased phosphoenolpyruvate carboxykinase expression. In addition, PINX rats display increased conversion of pyruvate into glucose at the end of the night. The regulatory mechanism suggests the participation of unfolded protein response (UPR), because PINX induces night-time increase in activating transcription factor 6 expression and prompts a circadian fashion of immunoglobulin heavy chain-binding protein, activating transcription factor 4, and CCAAT/enhancer-binding protein-homologous protein expression with Zenith values at the dark period. PINX also caused a night-time increase in Tribble 3 and regulatory-associated protein of mammalian target of rapamycin; both were reduced in liver of PINX rats treated with Mel. Treatment of PINX rats with 4-phenyl butyric acid, an inhibitor of UPR, restored night-time hepatic insulin sensitivity and abrogated gluconeogenesis in PINX rats. Altogether, the present data show that a circadian oscillation of UPR occurs in the liver due to the absence of Mel. The nocturnal UPR activation is related with night-time hepatic insulin resistance and increased gluconeogenesis in PINX rats.
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Affiliation(s)
- Tatiane C Nogueira
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
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29
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Abstract
Glucose homeostasis in mammals is achieved by the actions of counterregulatory hormones, namely insulin, glucagon and glucocorticoids. Glucose levels in the circulation are regulated by the liver, the metabolic centre which produces glucose when it is scarce in the blood. This process is catalysed by two rate-limiting enzymes, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) whose gene expression is regulated by hormones. Hormone response units (HRUs) present in the two genes integrate signals from various signalling pathways triggered by hormones. How such domains are arranged in the regulatory region of these two genes, how this complex regulation is accomplished and the latest advancements in the field are discussed in this review.
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30
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Le Lay J, Kaestner KH. The Fox genes in the liver: from organogenesis to functional integration. Physiol Rev 2010; 90:1-22. [PMID: 20086072 DOI: 10.1152/physrev.00018.2009] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Formation and function of the liver are highly controlled, essential processes. Multiple signaling pathways and transcriptional regulatory networks cooperate in this complex system. The evolutionarily conserved FOX, for Forkhead bOX, class of transcriptional regulators is critical to many aspects of liver development and function. The FOX proteins are small, mostly monomeric DNA binding factors containing the so-called winged helix DNA binding motif that distinguishes them from other classes of transcription factors. We discuss the biochemical and genetic roles of Foxa, Foxl1, Foxm1, and Foxo, as these have been shown to regulate many processes throughout the life of the organ, controlling both formation and function of the liver.
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Affiliation(s)
- John Le Lay
- Department of Genetics and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6145, USA
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31
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Ganjam GK, Dimova EY, Unterman TG, Kietzmann T. FoxO1 and HNF-4 are involved in regulation of hepatic glucokinase gene expression by resveratrol. J Biol Chem 2009; 284:30783-97. [PMID: 19740748 PMCID: PMC2781477 DOI: 10.1074/jbc.m109.045260] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/02/2009] [Indexed: 12/11/2022] Open
Abstract
Resveratrol, a polyphenol derived from grapes, exerts important effects on glucose and lipid metabolism, yet detailed mechanisms mediating these effects remain unknown. The liver plays a central role in energy homeostasis, and glucokinase (GK) is a key enzyme involved in glucose utilization. Resveratrol activates SIRT1 (sirtuin 1), which promotes deacetylation of the forkhead transcription factor FoxO1. Previously, we reported that FoxO1 can suppress and that HNF-4 can stimulate GK expression in the liver. Here, we examined the role of FoxO1 and HNF-4 in mediating resveratrol effects on liver GK expression. Resveratrol suppressed hepatic GK expression in vivo and in isolated hepatocytes, and knocking down FoxO1 with shRNAs disrupted this effect. Reporter gene, gel shift, supershift assay, and chromatin immunoprecipitation studies show that FoxO1 binds to the GK promoter and that the interplay between FoxO1 and HNF-4 within the GK promoter is essential for mediating the effects of resveratrol. Resveratrol promotes deacetylation of FoxO1 and enhances its recruitment to the FoxO-binding element. Conversely, resveratrol suppresses recruitment of HNF-4 to its binding site, and knockdown of FoxO1 blocks this effect of resveratrol. Coprecipitation and chromatin immunoprecipitation studies show that resveratrol enhances interaction between FoxO1 and HNF-4, reduces binding of HNF-4 to its own site, and promotes its recruitment to the FoxO site in a FoxO1-dependent manner. These results provide the first evidence that resveratrol represses GK expression via FoxO1 and that the interaction between FoxO1 and HNF-4 contributes to these effects of resveratrol.
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Affiliation(s)
- Goutham Kumar Ganjam
- From the Faculty of Chemistry, Department of Biochemistry, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
- the Department of Nutrient Physiology, Philipps University Marburg, Karl-von-Frisch-Strasse 8, D-35043 Marburg, Germany
| | - Elitsa Y. Dimova
- From the Faculty of Chemistry, Department of Biochemistry, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
- the Department of Biochemistry, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
| | - Terry G. Unterman
- the Departments of Medicine and Physiology and Biophysics, University of Illinois College of Medicine at Chicago, Chicago, Illinois 60612, and
- the **Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
| | - Thomas Kietzmann
- From the Faculty of Chemistry, Department of Biochemistry, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
- the Department of Biochemistry, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
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32
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The Irs1 branch of the insulin signaling cascade plays a dominant role in hepatic nutrient homeostasis. Mol Cell Biol 2009; 29:5070-83. [PMID: 19596788 DOI: 10.1128/mcb.00138-09] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We used a Cre-loxP approach to generate mice with varied expression of hepatic Irs1 and Irs2 to establish the contribution of each protein to hepatic nutrient homeostasis. While nutrient-sensitive transcripts were expressed nearly normally in liver lacking Irs2 (LKO2 mice), these transcripts were significantly dysregulated in liver lacking Irs1 (LKO1 mice) or Irs1 and Irs2 together (DKO mice). Similarly, a set of key gluconeogenic and lipogenic genes was regulated nearly normally by feeding in liver retaining a single Irs1 allele without Irs2 (DKO/1 mice) but was poorly regulated in liver retaining one Irs2 allele without Irs1 (DKO/2 mice). DKO/2 mice, but not DKO/1 mice, also showed impaired glucose tolerance and insulin sensitivity-though both Irs1 and Irs2 were required to suppress hepatic glucose production during hyperinsulinemic-euglycemic clamp. In contrast, either hepatic Irs1 or Irs2 mediated suppression of HGP by intracerebroventricular insulin infusion. After 12 weeks on a high-fat diet, postprandial tyrosine phosphorylation of Irs1 increased in livers of control and LKO2 mice, whereas tyrosine phosphorylation of Irs2 decreased in control and LKO1 mice. Moreover, LKO1 mice -- but not LKO2 mice -- that were fed a high-fat diet developed postprandial hyperglycemia. We conclude that Irs1 is the principal mediator of hepatic insulin action that maintains glucose homeostasis.
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33
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Hatta M, Liu F, Cirillo LA. Acetylation curtails nucleosome binding, not stable nucleosome remodeling, by FoxO1. Biochem Biophys Res Commun 2009; 379:1005-8. [PMID: 19146829 DOI: 10.1016/j.bbrc.2009.01.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 01/04/2009] [Indexed: 10/21/2022]
Abstract
Transcriptional activity of FoxO factors is controlled through the actions of multiple growth factors signaling through protein kinase B, whereby phosphorylation of FoxO factors inhibits FoxO-mediated transactivation by promoting nuclear export. Phosphorylation of FoxO factors is enhanced by p300-mediated acetylation, which decreases their affinity for DNA. The negative effect of acetylation on FoxO DNA binding, together with nuclear FoxO mobility, is eliminated by over-expression of the de-acetylase Sirt1, suggesting that acetylation mobilizes FoxO factors in chromatin for inducible gene expression. Here, we show that acetylation significantly curtails the affinity of FoxO1 for its binding sites in nucleosomal DNA but has no effect on either stable nucleosome binding or remodeling by this factor. We suggest that, while acetylation provides a first, essential step toward mobilizing FoxO factors for inducible gene repression, additional mechanisms exist for overcoming their inherent capacity to stably bind and remodel nuclear chromatin.
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Affiliation(s)
- M Hatta
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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34
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Kodama S, Negishi M. Phenobarbital Confers its Diverse Effects by Activating the Orphan Nuclear Receptor Car. Drug Metab Rev 2008; 38:75-87. [PMID: 16684649 DOI: 10.1080/03602530600569851] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In the early 1960s, phenobarbital (PB) was shown to induce hepatic drug metabolism and the induction was implicated in the molecular mechanism of drug tolerance development. Since then, it has become evident that PB not only induces drug metabolism, but also triggers pleiotropic effects on liver function, such as cell growth and communication, proliferation of the endoplasmic reticulum, tumor promotion, glucose metabolism, steroid/thyroid hormone metabolism, and bile acid synthesis. Upon activation by PB and numerous PB-type inducers, the nuclear receptor CAR mediates those pleiotropic actions by regulating various hepatic genes, utilizing multiple regulatory mechanisms.
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Affiliation(s)
- Susumu Kodama
- Pharmacogenetics Section, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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35
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Rixhon M, Tichomirowa MA, Tamagno G, Daly AF, Beckers A. Current and future perspectives on recombinant growth hormone for the treatment of obesity. Expert Rev Endocrinol Metab 2008; 3:75-90. [PMID: 30743787 DOI: 10.1586/17446651.3.1.75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The similarities between patients with untreated growth hormone (GH) deficiency and those with the cardiometabolic syndrome and the beneficial effects of recombinant human GH (rhGH) on body composition have led to the hypothesis that rhGH treatment may have utility in obesity. GH release is reduced in the setting of obesity, primarily due to hyperinsulinism and increased free fatty acid levels. We reviewed the outcomes of 23 clinical studies carried out between 1987 and 2006 that examined the effects of rhGH administration in the obese state. Typically, changes in overall body weight do not occur with rhGH therapy; however, assessment of body composition demonstrates reductions in visceral abdominal fat. Data on the effects of rhGH on lipid and carbohydrate metabolic profiles in obese patients are less clear-cut, with a subset of studies showing a beneficial effect and others a neutral effect. Given the increasing burden of obesity in the general population and the current paucity of effective therapies, it is useful to consider the data on rhGH and obesity from a clinical perspective to highlight potential treatment strategies that harness the somatotropic axis.
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Affiliation(s)
- Martine Rixhon
- a Department Universitaire de Médecine Générale, University of Liège, Liège, Belgium
| | - Maria A Tichomirowa
- b Department of Endocrinology, CHU de Liège, University of Liège, Liège, Belgium
| | - Gianluca Tamagno
- b Department of Endocrinology, CHU de Liège, University of Liège, Liège, Belgium
| | - Adrian F Daly
- b Department of Endocrinology, CHU de Liège, University of Liège, Liège, Belgium
| | - Albert Beckers
- c Department of Endocrinology, CHU de Liège, 4000 Liège, Belgium.
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36
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Hatta M, Cirillo LA. Chromatin Opening and Stable Perturbation of Core Histone:DNA Contacts by FoxO1. J Biol Chem 2007; 282:35583-93. [DOI: 10.1074/jbc.m704735200] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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37
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Clark AR. Anti-inflammatory functions of glucocorticoid-induced genes. Mol Cell Endocrinol 2007; 275:79-97. [PMID: 17561338 DOI: 10.1016/j.mce.2007.04.013] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 04/25/2007] [Indexed: 01/12/2023]
Abstract
There is a broad consensus that glucocorticoids (GCs) exert anti-inflammatory effects largely by inhibiting the function of nuclear factor kappaB (NFkappaB) and consequently the transcription of pro-inflammatory genes. In contrast, side effects are thought to be largely dependent on GC-induced gene expression. Biochemical and genetic evidence suggests that the positive and negative effects of GCs on transcription can be uncoupled from one another. Hence, novel GC-related drugs that mediate inhibition of NFkappaB but do not activate gene expression are predicted to retain therapeutic effects but cause fewer or less severe side effects. Here, we critically re-examine the evidence in favor of the consensus, binary model of GC action and discuss conflicting evidence, which suggests that anti-inflammatory actions of GCs depend on the induction of anti-inflammatory mediators. We propose an alternative model, in which GCs exert anti-inflammatory effects at both transcriptional and post-transcriptional levels, both by activating and inhibiting expression of target genes. The implications of such a model in the search for safer anti-inflammatory drugs are discussed.
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Affiliation(s)
- Andrew R Clark
- Kennedy Institute of Rheumatology Division, Imperial College London, 1 Aspenlea Road, Hammersmith, London W6 8LH, United Kingdom.
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38
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Matsumoto M, Pocai A, Rossetti L, Depinho RA, Accili D. Impaired regulation of hepatic glucose production in mice lacking the forkhead transcription factor Foxo1 in liver. Cell Metab 2007; 6:208-16. [PMID: 17767907 DOI: 10.1016/j.cmet.2007.08.006] [Citation(s) in RCA: 477] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 06/12/2007] [Accepted: 08/13/2007] [Indexed: 01/30/2023]
Abstract
The hallmark of type 2 diabetes is excessive hepatic glucose production. Several transcription factors and coactivators regulate this process in cultured cells. But gene ablation experiments have yielded few clues as to the physiologic mediators of this process in vivo. We show that inactivation of the gene encoding forkhead protein Foxo1 in mouse liver results in 40% reduction of glucose levels at birth and 30% reduction in adult mice after a 48 hr fast. Gene expression and glucose clamp studies demonstrate that Foxo1 ablation impairs fasting- and cAMP-induced glycogenolysis and gluconeogenesis. Pgc1alpha is unable to induce gluconeogenesis in Foxo1-deficient hepatocytes, while the cAMP response is significantly blunted. Conversely, Foxo1 deletion in liver curtails excessive glucose production caused by generalized ablation of insulin receptors and prevents neonatal diabetes and hepatosteatosis in insulin receptor knockout mice. The data provide a unifying mechanism for regulation of hepatic glucose production by cAMP and insulin.
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Affiliation(s)
- Michihiro Matsumoto
- Naomi Berrie Diabetes Center, Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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39
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Chakravarty K, Hanson RW. Insulin regulation of phosphoenolpyruvate carboxykinase-c gene transcription: the role of sterol regulatory element-binding protein 1c. Nutr Rev 2007; 65:S47-56. [PMID: 17605314 DOI: 10.1111/j.1753-4887.2007.tb00328.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
The effect of insulin on the regulation of phosphoenolpyruvate carboxykinase C (PEPCK-C) gene transcription, while pivotal for control of carbohydrate metabolism, constitutes only a small part of its overall action in cellular processes. Transcription of the PEPCK-C gene is the target for a number of pathways involved in the signal transduction initiated by insulin, and these processes involve an array of transcription factors and co-regulatory proteins that either alone or in concert bind to a subset of sites in the gene promoter to regulate its expression. This review will focus on a specific transcription factor, sterol regulatory element-binding protein 1c (SREBP-1c), and its role in the control of PEPCK-C gene transcription.
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Affiliation(s)
- Kaushik Chakravarty
- Department of Cardiovascular Medicine, Discovery Biology, Pfizer La Jolla, San Diego, California 92121, USA.
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Schweizer-Groyer G, Fallot G, Cadepond F, Girard C, Groyer A. The cAMP-responsive unit of the human insulin-like growth factor-binding protein-1 coinstitutes a functional insulin-response element. Ann N Y Acad Sci 2007; 1091:296-309. [PMID: 17341623 DOI: 10.1196/annals.1378.075] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Insulin-like growth factor-binding protein-1 (IGFBP-1) is one of the genes involved in glucose homeostasis. In vivo, its level is increased by counter-regulatory hormones (glucocorticoids and glucagon via its second messenger cAMP) and decreased by insulin, these variations being primarily correlated with IGFBP-1 gene transcription. Previous reports described a functional insulin response element (IRE), immediately 5'- to the glucocorticoid response element (GRE). This IRE has been shown to mediate partial inhibition (1) of basal IGFBP-1 promoter activity and (2) of glucocorticoid-induced stimulation of gene transcription by insulin. In this work, using human HepG2 hepatoma cells as a model system, we showed: (1) that insulin inhibited both basal and cAMP-induced hIGFBP-1 promoter (nt-1 to -341) activity; (2) that in the absence of insulin, forkhead box class O (FOXO) transcription factors enhance constitutive hIGFBP-1 promoter activity without interfering with the stimulatory effect of cAMP; (3) that PI-3' kinase signaling is involved in the inhibition of constitutive and cAMP-induced promoter activities by insulin; (4) that wild-type FOXO-1 mediates the inhibitory effect of insulin on the promoter, although FOXO-1(Ala3), a nonphosphorylatable mutant of FOXO-1, does not; (5) that the cAMP-responsive unit (CRU), that includes a putative IRE (nt-265 to -282) and a cAMP responsive element (CRE; nt-258 to -263), is sufficient per se to mediate both cAMP stimulation of a heterologous promoter, and inhibition of both basal and cAMP-induced promoter activities by insulin; and (6) that the inhibitory effects of insulin on the isolated CRU are mediated by the FOXOs. This study is the first evidence for the occurrence of a second IRE within hIGFBP-1 promoter sequences, IRE(CRU), located 5'- to the CRE.
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Mounier C, Posner BI. Transcriptional regulation by insulin: from the receptor to the gene. Can J Physiol Pharmacol 2007; 84:713-24. [PMID: 16998535 DOI: 10.1139/y05-152] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Insulin, after binding to its receptor, regulates many cellular processes and the expression of several genes. For a subset of genes, insulin exerts a negative effect on transcription; for others, the effect is positive. Insulin controls gene transcription by modifying the binding of transcription factors on insulin-response elements or by regulating their transcriptional activities. Different insulin-signaling cascades have been characterized as mediating the insulin effect on gene transcription. In this review, we analyze recent data on the molecular mechanisms, mostly in the liver, through which insulin exerts its effect. We first focus on the key transcription factors (viz. Foxo, sterol-response-element-binding protein family (SREBP), and Sp1) involved in the regulation of gene transcription by insulin. We then present current information on the way insulin downregulates and upregulates gene transcription, using as examples of downregulation phosphoenolpyruvate carboxykinase (PEPCK) and insulin-like growth factor binding protein 1 (IGFBP-1) genes and of upregulation the fatty acid synthase and malic enzyme genes. The last part of the paper focuses on the signaling cascades activated by insulin in the liver, leading to the modulation of gene transcription.
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Affiliation(s)
- Catherine Mounier
- BioMed, Department of Biological Science, University of Quebec in Montreal, 141 President Kennedy, Montreal, QC H2X 3Y7, Canada
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42
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Hall RK, Wang XL, George L, Koch SR, Granner DK. Insulin represses phosphoenolpyruvate carboxykinase gene transcription by causing the rapid disruption of an active transcription complex: a potential epigenetic effect. Mol Endocrinol 2006; 21:550-63. [PMID: 17095578 DOI: 10.1210/me.2006-0307] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Insulin represses gluconeogenesis, in part, by inhibiting the transcription of genes that encode rate-determining enzymes, such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G-6-Pase). Glucocorticoids stimulate expression of the PEPCK gene but the repressive action of insulin is dominant. Here, we show that treatment of H4IIE hepatoma cells with the synthetic glucocorticoid, dexamethasone (dex), induces the accumulation of glucocorticoid receptor, as well as many transcription factors, coregulators, and RNA polymerase II, on the PEPCK gene promoter. The addition of insulin to dex-treated cells causes the rapid dissociation of glucocorticoid receptor, polymerase II, and several key transcriptional regulators from the PEPCK gene promoter. These changes are temporally related to the reduced rate of PEPCK gene transcription. A similar disruption of the G-6-Pase gene transcription complex was observed. Additionally, insulin causes the rapid demethylation of arginine-17 on histone H3 of both genes. This rapid, insulin-induced, histone demethylation is temporally related to the disruption of the PEPCK and G-6-Pase gene transcription complex, and may be causally related to the mechanism by which insulin represses transcription of these genes.
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Affiliation(s)
- Robert K Hall
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 707 Light Hall, Nashville, Tennessee 37232-0615, USA
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Martin B, Mattson MP, Maudsley S. Caloric restriction and intermittent fasting: two potential diets for successful brain aging. Ageing Res Rev 2006; 5:332-53. [PMID: 16899414 PMCID: PMC2622429 DOI: 10.1016/j.arr.2006.04.002] [Citation(s) in RCA: 245] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 04/21/2006] [Accepted: 04/21/2006] [Indexed: 12/14/2022]
Abstract
The vulnerability of the nervous system to advancing age is all too often manifest in neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. In this review article we describe evidence suggesting that two dietary interventions, caloric restriction (CR) and intermittent fasting (IF), can prolong the health-span of the nervous system by impinging upon fundamental metabolic and cellular signaling pathways that regulate life-span. CR and IF affect energy and oxygen radical metabolism, and cellular stress response systems, in ways that protect neurons against genetic and environmental factors to which they would otherwise succumb during aging. There are multiple interactive pathways and molecular mechanisms by which CR and IF benefit neurons including those involving insulin-like signaling, FoxO transcription factors, sirtuins and peroxisome proliferator-activated receptors. These pathways stimulate the production of protein chaperones, neurotrophic factors and antioxidant enzymes, all of which help cells cope with stress and resist disease. A better understanding of the impact of CR and IF on the aging nervous system will likely lead to novel approaches for preventing and treating neurodegenerative disorders.
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Affiliation(s)
- Bronwen Martin
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
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44
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Onuma H, Vander Kooi BT, Boustead JN, Oeser JK, O'Brien RM. Correlation between FOXO1a (FKHR) and FOXO3a (FKHRL1) binding and the inhibition of basal glucose-6-phosphatase catalytic subunit gene transcription by insulin. Mol Endocrinol 2006; 20:2831-47. [PMID: 16840535 DOI: 10.1210/me.2006-0085] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Insulin inhibits transcription of the genes encoding the glucose-6-phosphatase catalytic subunit (G6Pase), phosphoenolpyruvate carboxykinase, and IGF binding protein-1 through insulin response sequences (IRSs) that share the same core sequence, T(G/A)TTTT(G/T). The transcription factors FOXO1a and FOXO3a have been shown to bind these elements, but there are conflicting reports as to whether this binding correlates with the action of insulin on gene transcription. Some researchers concluded, from overexpression experiments using FOXO1a, that binding correlated with the insulin response, whereas others concluded, mainly from gel retardation competition experiments using FOXO3a, that it did not. We show here that, although these factors can differentially activate gene transcription in a context-dependent manner, these conflicting data are not explained by a difference in FOXO1a and FOXO3a binding specificity. Instead, we find that gel retardation competition and binding experiments give different results; the latter reveal a correlation between FOXO1a/3a binding and the inhibition of basal G6Pase gene transcription by insulin. In addition, these data show that the binding of FOXO1a/3a to two adjacent IRSs in the G6Pase promoter is cooperative and that promoter context alters the specific IRS base requirements for FOXO1a-stimulated fusion gene expression. Surprisingly, an analysis of insulin action mediated through the G6Pase and IGF binding protein-1 IRSs in the context of a heterologous thymidine kinase promoter reveals that signaling through the latter does not support the accepted model for insulin-stimulated FOXO nuclear exclusion.
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Affiliation(s)
- Hiroshi Onuma
- Department of Molecular Physiology and Biophysics, 761 Preston Research Building, Vanderbilt University Medical School, Nashville, Tennessee 37232-0615, USA
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45
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Luque RM, Kineman RD. Impact of obesity on the growth hormone axis: evidence for a direct inhibitory effect of hyperinsulinemia on pituitary function. Endocrinology 2006; 147:2754-63. [PMID: 16513828 DOI: 10.1210/en.2005-1549] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
There is a negative relationship between obesity and GH. However, it is not known how metabolic changes, associated with obesity, lead to a reduction in GH output. This study examined the GH axis of two mouse models of obesity, the leptin-deficient (ob/ob) mouse and the diet-induced obese (DIO; high-fat fed) mouse. Both models displayed hyperglycemia and hyperinsulinemia with reduced expression of GH as well as reduced expression of pituitary receptors important for GH synthesis and release [GHRH receptor (DIO only) and the ghrelin receptor (ob/ob and DIO)]. These pituitary changes were not accompanied by changes in hypothalamic expression of GHRH or somatostatin; suggesting that alterations in pituitary function may be precipitated in part by direct effects of systemic signals. Of the metabolic and hormonal parameters examined (insulin, glucose, corticosterone, free fatty acids, ghrelin, and IGF-I), only insulin/glucose showed a significant, and negative, correlation with pituitary expression. Pituitaries of DIO mice remained responsive to the acute in vivo actions of insulin, as assessed by phosphorylation of Akt, despite systemic (skeletal muscle and fat) insulin resistance. In addition, treating primary pituitary cell cultures from lean mice with insulin reduced GH release as well as GH, GHRH receptor, and ghrelin receptor mRNA levels compared with vehicle-treated controls, where the magnitude of suppression of pituitary mRNA levels was similar to that observed in the DIO mouse. These results coupled with the fact that the pituitary expresses the insulin receptor at levels comparable to tissues classically considered insulin sensitive, indicates high circulating insulin levels can directly contribute to the suppression of GH synthesis and release in the obese state.
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Affiliation(s)
- Raul M Luque
- Section of Endocrinology and Metabolism, Department of Medicine, University of Illinois at Chicago, Illinois, USA
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Zhang W, Patil S, Chauhan B, Guo S, Powell DR, Le J, Klotsas A, Matika R, Xiao X, Franks R, Heidenreich KA, Sajan MP, Farese RV, Stolz DB, Tso P, Koo SH, Montminy M, Unterman TG. FoxO1 regulates multiple metabolic pathways in the liver: effects on gluconeogenic, glycolytic, and lipogenic gene expression. J Biol Chem 2006; 281:10105-17. [PMID: 16492665 DOI: 10.1074/jbc.m600272200] [Citation(s) in RCA: 378] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
FoxO transcription factors are important targets of insulin action. To better understand the role of FoxO proteins in the liver, we created transgenic mice expressing constitutively active FoxO1 in the liver using the alpha1-antitrypsin promoter. Fasting glucose levels are increased, and glucose tolerance is impaired in transgenic (TGN) versus wild type (WT) mice. Interestingly, fasting triglyceride and cholesterol levels are reduced despite hyperinsulinemia, and post-prandial changes in triglyceride levels are markedly suppressed in TGN versus WT mice. Activation of pro-lipogenic signaling pathways (atypical protein kinase C and protein kinase B) and the ability to suppress beta-hydroxybutyrate levels are not impaired in TGN. In contrast, de novo lipogenesis measured with (3)H(2)O is suppressed by approximately 70% in the liver of TGN versus WT mice after refeeding. Gene-array studies reveal that the expression of genes involved in gluconeogenesis, glycerol transport, and amino acid catabolism is increased, whereas genes involved in glucose utilization by glycolysis, the pentose phosphate shunt, lipogenesis, and sterol synthesis pathways are suppressed in TGN versus WT. Studies with adenoviral vectors in isolated hepatocytes confirm that FoxO1 stimulates expression of gluconeogenic genes and suppresses expression of genes involved in glycolysis, the shunt pathway, and lipogenesis, including glucokinase and SREBP-1c. Together, these results indicate that FoxO proteins promote hepatic glucose production through multiple mechanisms and contribute to the regulation of other metabolic pathways important in the adaptation to fasting and feeding in the liver, including glycolysis, the pentose phosphate shunt, and lipogenic and sterol synthetic pathways.
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Affiliation(s)
- Wenwei Zhang
- Departments of Medicine and Physiology and Biophysics, University of Illinois College of Medicine, Chicago, IL 60612, USA
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Lemieux ME, Yang X, Jardine K, He X, Jacobsen KX, Staines WA, Harper ME, McBurney MW. The Sirt1 deacetylase modulates the insulin-like growth factor signaling pathway in mammals. Mech Ageing Dev 2006; 126:1097-105. [PMID: 15964060 DOI: 10.1016/j.mad.2005.04.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2004] [Revised: 02/16/2005] [Accepted: 04/27/2005] [Indexed: 11/29/2022]
Abstract
The lifespan of the nematode, Caenorhabditis elegans, can be extended by mutations affecting components of the insulin-like growth factor (IGF) signaling cascade or by overexpression of SIR2, an NAD+-dependent protein deacetylase. The mammalian homologue of SIR2, Sirt1, has been shown to modulate the activity of FoxO, a transcription factor that is downstream of the IGF signaling system. These results suggest that Sirt1 ought to affect the IGF pathway. We report here evidence that this is the case in mice. The loss of Sirt1 protein in mice results in increased expression of the IGF binding protein IGFBP1, a secreted modulator of IGF function. A number of the anatomical characteristics of Sirt1-null mice closely resemble those of transgenic mice overexpressing IGFBP1. Our data suggest that Sirt1 is part of a regulatory loop that limits the production of IGFBP1 thereby modulating IGF signaling.
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Affiliation(s)
- M E Lemieux
- Ottawa Regional Cancer Centre and Department of Medicine, Faculty of Medicine, 501 Smyth Road, University of Ottawa, Ottawa, Canada K1H 1C4
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Greer EL, Brunet A. FOXO transcription factors at the interface between longevity and tumor suppression. Oncogene 2005; 24:7410-25. [PMID: 16288288 DOI: 10.1038/sj.onc.1209086] [Citation(s) in RCA: 984] [Impact Index Per Article: 51.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A wide range of human diseases, including cancer, has a striking age-dependent onset. However, the molecular mechanisms that connect aging and cancer are just beginning to be unraveled. FOXO transcription factors are promising candidates to serve as molecular links between longevity and tumor suppression. These factors are major substrates of the protein kinase Akt. In the presence of insulin and growth factors, FOXO proteins are relocalized from the nucleus to the cytoplasm and degraded via the ubiquitin-proteasome pathway. In the absence of growth factors, FOXO proteins translocate to the nucleus and upregulate a series of target genes, thereby promoting cell cycle arrest, stress resistance, or apoptosis. Stress stimuli also trigger the relocalization of FOXO factors into the nucleus, thus allowing an adaptive response to stress stimuli. Consistent with the notion that stress resistance is highly coupled with lifespan extension, activation of FOXO transcription factors in worms and flies increases longevity. Emerging evidence also suggests that FOXO factors play a tumor suppressor role in a variety of cancers. Thus, FOXO proteins translate environmental stimuli into changes in gene expression programs that may coordinate organismal longevity and tumor suppression.
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Affiliation(s)
- Eric L Greer
- Department of Genetics, Stanford University, CA 94305, USA
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49
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Almon RR, Lai W, DuBois DC, Jusko WJ. Corticosteroid-regulated genes in rat kidney: mining time series array data. Am J Physiol Endocrinol Metab 2005; 289:E870-82. [PMID: 15985454 PMCID: PMC3752664 DOI: 10.1152/ajpendo.00196.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Kidney is a major target for adverse effects associated with corticosteroids. A microarray dataset was generated to examine changes in gene expression in rat kidney in response to methylprednisolone. Four control and 48 drug-treated animals were killed at 16 times after drug administration. Kidney RNA was used to query 52 individual Affymetrix chips, generating data for 15,967 different probe sets for each chip. Mining techniques applicable to time series data that identify drug-regulated changes in gene expression were applied. Four sequential filters eliminated probe sets that were not expressed in the tissue, not regulated by drug, or did not meet defined quality control standards. These filters eliminated 14,890 probe sets (94%) from further consideration. Application of judiciously chosen filters is an effective tool for data mining of time series datasets. The remaining data can then be further analyzed by clustering and mathematical modeling. Initial analysis of this filtered dataset identified a group of genes whose pattern of regulation was highly correlated with prototype corticosteroid enhanced genes. Twenty genes in this group, as well as selected genes exhibiting either downregulation or no regulation, were analyzed for 5' GRE half-sites conserved across species. In general, the results support the hypothesis that the existence of conserved DNA binding sites can serve as an important adjunct to purely analytic approaches to clustering genes into groups with common mechanisms of regulation. This dataset, as well as similar datasets on liver and muscle, are available online in a format amenable to further analysis by others.
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Affiliation(s)
- Richard R Almon
- Dept. of Biological Sciences, SUNY at Buffalo, Buffalo, NY 14260, USA.
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Abstract
There is increasing evidence that Forkhead box 'Other' (FoxO) proteins, a subgroup of the Forkhead transcription factor family, have an important role in mediating the effects of insulin and growth factors on diverse physiological functions, including cell proliferation, apoptosis and metabolism. Genetic studies in Caenorhabditis (Caenorhabditis elegans) and Drosophila demonstrate that FoxO proteins are ancient targets of insulin-like signaling involved in the regulation of metabolism and longevity. Studies in mammalian cells reveal that FoxO proteins regulate cell cycle progression and promote resistance to oxidative stress; both in vivo and cell culture studies support the concept that FoxO proteins have an important role in mediating the effects of insulin on metabolism, including its effects on hepatic glucose production. Phosphorylation and acetylation modulate FoxO function and control nuclear-cytoplasmic shuttling, DNA binding and protein-protein interactions. FoxO transcription factors exert positive and negative effects on gene expression, through direct binding to DNA target sites and protein-protein interactions with other transcription factors and coactivators. This paper provides an overview of studies leading to the identification of FoxO proteins as targets of insulin action and the mechanisms mediating the effects of insulin-like signaling on FoxO function, emphasizing the role of FoxO proteins in mediating the effects of insulin on metabolism.
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Affiliation(s)
- Andreas Barthel
- Department of Endocrinology, Diabetes and Rheumatology, University Hospital Düsseldorf, Moorenstrasse 5, D-40225 Düsseldorf, Germany
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