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Yang X, Brobst D, Chan WS, Tse MCL, Herlea-Pana O, Ahuja P, Bi X, Zaw AM, Kwong ZSW, Jia WH, Zhang ZG, Zhang N, Chow SKH, Cheung WH, Louie JCY, Griffin TM, Nong W, Hui JHL, Du GH, Noh HL, Saengnipanthkul S, Chow BKC, Kim JK, Lee CW, Chan CB. Muscle-generated BDNF is a sexually dimorphic myokine that controls metabolic flexibility. Sci Signal 2019; 12:12/594/eaau1468. [PMID: 31409756 DOI: 10.1126/scisignal.aau1468] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability of skeletal muscle to switch between lipid and glucose oxidation for ATP production during metabolic stress is pivotal for maintaining systemic energy homeostasis, and dysregulation of this metabolic flexibility is a dominant cause of several metabolic disorders. However, the molecular mechanism that governs fuel selection in muscle is not well understood. Here, we report that brain-derived neurotrophic factor (BDNF) is a fasting-induced myokine that controls metabolic reprograming through the AMPK/CREB/PGC-1α pathway in female mice. Female mice with a muscle-specific deficiency in BDNF (MBKO mice) were unable to switch the predominant fuel source from carbohydrates to fatty acids during fasting, which reduced ATP production in muscle. Fasting-induced muscle atrophy was also compromised in female MBKO mice, likely a result of autophagy inhibition. These mutant mice displayed myofiber necrosis, weaker muscle strength, reduced locomotion, and muscle-specific insulin resistance. Together, our results show that muscle-derived BDNF facilitates metabolic adaption during nutrient scarcity in a gender-specific manner and that insufficient BDNF production in skeletal muscle promotes the development of metabolic myopathies and insulin resistance.
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Affiliation(s)
- Xiuying Yang
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 634, Oklahoma City, OK 73104, USA.,State Key Laboratory of Bioactive Substance and Function of Natural Medicines and Beijing Key Laboratory of Drug Target and Screening Research, Institute of Materia Medica of Peking Union Medical College, Beijing 100050, China
| | - Daniel Brobst
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 634, Oklahoma City, OK 73104, USA
| | - Wing Suen Chan
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Margaret Chui Ling Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Oana Herlea-Pana
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 634, Oklahoma City, OK 73104, USA
| | - Palak Ahuja
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Xinyi Bi
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Aung Moe Zaw
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong.,Department of Chemical Engineering, University of Waterloo, ON N2L 3G1, Canada
| | - Zara Sau Wa Kwong
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Wei-Hua Jia
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines and Beijing Key Laboratory of Drug Target and Screening Research, Institute of Materia Medica of Peking Union Medical College, Beijing 100050, China
| | - Zhong-Gou Zhang
- Department of Colorectal Cancer Oncological Surgery, Large-Scale Data Analysis Center of Cancer Precision Medicine, Cancer Hospital of Chinese Medical University, Liaoning Provincial Cancer Institute and Hospital, Shenyang 110042, China
| | - Ning Zhang
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, 5/F Lui Che Woo Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
| | - Simon Kwoon Ho Chow
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, 5/F Lui Che Woo Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
| | - Wing Hoi Cheung
- Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, 5/F Lui Che Woo Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong
| | - Jimmy Chun Yu Louie
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Timothy M Griffin
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., BMSB 634, Oklahoma City, OK 73104, USA.,Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.,Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Wenyan Nong
- School of Life Sciences, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Jerome Ho Lam Hui
- School of Life Sciences, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Guan-Hua Du
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines and Beijing Key Laboratory of Drug Target and Screening Research, Institute of Materia Medica of Peking Union Medical College, Beijing 100050, China
| | - Hye Lim Noh
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Suchaorn Saengnipanthkul
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Billy K C Chow
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong
| | - Jason K Kim
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Chi Wai Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong.
| | - Chi Bun Chan
- School of Biological Sciences, The University of Hong Kong, 6N01 Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong. .,State Key Laboratory of Pharmaceutical Biotechnology, University of Hong Kong, Hong Kong
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2
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Wood J, Tse MCL, Yang X, Brobst D, Liu Z, Pang BPS, Chan WS, Zaw AM, Chow BKC, Ye K, Lee CW, Chan CB. BDNF mimetic alleviates body weight gain in obese mice by enhancing mitochondrial biogenesis in skeletal muscle. Metabolism 2018; 87:113-122. [PMID: 29935237 DOI: 10.1016/j.metabol.2018.06.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/14/2018] [Accepted: 06/17/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND 7,8-Dihydroxyflavone (7,8-DHF) is a small molecular weight compound that mimics the functions of brain-derived neurotrophic factor (BDNF). The current study aims to elucidate the molecular mechanism of 7,8-DHF-induced body weight regulation. METHODS Obese female C57/BL6 (20-week-old) mice that have been fed with high-fat diet for 13 weeks were treated with 7,8-DHF for 9 weeks. Various biochemical and molecular analyses were performed to examine the signal transduction pathway, metabolite content, and mitochondrial mass in the animals. Moreover, systemic energy metabolism and insulin sensitivity were determined by indirect calorimetry and insulin/glucose-tolerance tests. We have also determined the metabolic actions of 7,8-DHF on cultured myotubes. RESULTS 7,8-DHF treatment increased cellular respiration by promoting mitochondrial biogenesis in cultured skeletal muscle cells. In diet-induced obese mice, subsequent 7,8-DHF consumption triggered the AMPK/CREB/PGC-1α pathways to increase the muscular mitochondrial content. Systemic energy metabolism was thus elevated, which reduced the body weight gain in obese animals. Consequently, hyperlipidemia, hyperglycemia hyperinsulinemia, and ectopic lipid accumulation in skeletal muscle and liver of the obese animals were alleviated after 7,8-DHF treatment. Moreover, insulin sensitivity of the obese muscle was improved after 7,8-DHF consumption. CONCLUSION 7,8-DHF treatment increases muscular mitochondrial respiration and systemic energy expenditure, which alleviates the body weight gain and partially reverse the metabolic abnormalities induced by obesity.
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Affiliation(s)
- John Wood
- Department of Physiology, the University of Oklahoma Health Sciences Center, Oklahoma City, USA
| | - Margaret Chui Ling Tse
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Xiuying Yang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Beijing Key Laboratory of Drug Target and Screening Research, Institute of Materia Medica of Peking Union Medical College, Beijing, China
| | - Daniel Brobst
- Department of Physiology, the University of Oklahoma Health Sciences Center, Oklahoma City, USA
| | - Zhixue Liu
- Department of Physiology, the University of Oklahoma Health Sciences Center, Oklahoma City, USA
| | - Brian Pak Shing Pang
- School of Biological Sciences, the University of Hong Kong, Hong Kong, SAR, China
| | - Wing Suen Chan
- School of Biological Sciences, the University of Hong Kong, Hong Kong, SAR, China
| | - Aung Moe Zaw
- School of Biological Sciences, the University of Hong Kong, Hong Kong, SAR, China
| | - Billy K C Chow
- School of Biological Sciences, the University of Hong Kong, Hong Kong, SAR, China
| | - Keqiang Ye
- Department of Pathology, Emory University School of Medicine, Atlanta, USA
| | - Chi Wai Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, China
| | - Chi Bun Chan
- School of Biological Sciences, the University of Hong Kong, Hong Kong, SAR, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, SAR, China.
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3
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Tse MCL, Herlea-Pana O, Brobst D, Yang X, Wood J, Hu X, Liu Z, Lee CW, Zaw AM, Chow BKC, Ye K, Chan CB. Tumor Necrosis Factor-α Promotes Phosphoinositide 3-Kinase Enhancer A and AMP-Activated Protein Kinase Interaction to Suppress Lipid Oxidation in Skeletal Muscle. Diabetes 2017; 66:1858-1870. [PMID: 28404596 PMCID: PMC5482076 DOI: 10.2337/db16-0270] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 03/29/2017] [Indexed: 12/12/2022]
Abstract
Tumor necrosis factor-α (TNF-α) is an inflammatory cytokine that plays a central role in obesity-induced insulin resistance. It also controls cellular lipid metabolism, but the underlining mechanism is poorly understood. We report in this study that phosphoinositide 3-kinase enhancer A (PIKE-A) is a novel effector of TNF-α to facilitate its metabolic modulation in the skeletal muscle. Depletion of PIKE-A in C2C12 myotubes diminished the inhibitory activities of TNF-α on mitochondrial respiration and lipid oxidation, whereas PIKE-A overexpression exacerbated these cellular responses. We also found that TNF-α promoted the interaction between PIKE-A and AMP-activated protein kinase (AMPK) to suppress its kinase activity in vitro and in vivo. As a result, animals with PIKE ablation in the skeletal muscle per se display an upregulation of AMPK phosphorylation and a higher preference to use lipid as the energy production substrate under high-fat diet feeding, which mitigates the development of diet-induced hyperlipidemia, ectopic lipid accumulation, and muscle insulin resistance. Hence, our data reveal PIKE-A as a new signaling factor that is important for TNF-α-initiated metabolic changes in skeletal muscle.
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Affiliation(s)
- Margaret Chui Ling Tse
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Oana Herlea-Pana
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Daniel Brobst
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Xiuying Yang
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
- Drug Screening Center, Institute of Materia Medica, Beijing, People's Republic of China
| | - John Wood
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Xiang Hu
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Zhixue Liu
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Chi Wai Lee
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Aung Moe Zaw
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Billy K C Chow
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, People's Republic of China
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA
| | - Chi Bun Chan
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, People's Republic of China
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4
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Kim SE, Choo J, Yoon J, Chu JR, Bae YJ, Lee S, Park T, Sung MK. Genome-wide analysis identifies colonic genes differentially associated with serum leptin and insulin concentrations in C57BL/6J mice fed a high-fat diet. PLoS One 2017; 12:e0171664. [PMID: 28170448 PMCID: PMC5295695 DOI: 10.1371/journal.pone.0171664] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/24/2017] [Indexed: 02/07/2023] Open
Abstract
Obesity-induced chronic inflammation is known to increase the risk of ulcerative colitis, Crohn's disease, and colorectal cancer. Accumulating evidence suggests that leptin and insulin are key molecules linking obesity with diseases of the lower intestine. Here, we identified serum phenotype-associated genes in the colon of diet-induced obese mice as early biomarkers of obesity-associated colonic diseases. C57BL/6J mice were fed with either normal diet (ND, 15% of fat calories) or high-fat diet (HFD, 45% of fat calories) for 8 weeks. Serum concentrations of insulin, insulin-like growth factor-1 (IGF-1), leptin, and adiponectin were measured as obesity-related phenotypic markers. Genome-wide gene expression profiles of colon tissue were determined, followed by statistical analyses to detect differentially expressed and serum phenotype-associated genes. HFD-fed mice showed higher serum concentrations of leptin (P < 0.001) and insulin (P < 0.01) than those in the ND group, whereas serum IGF-1 and adiponectin concentrations did not differ between the two dietary groups. Among differentially expressed genes affected by HFD, 135, 128, 110, and 341 genes were associated with serum levels of leptin, insulin, IGF-1, and adiponectin, respectively. We identified 17 leptin-associated genes and 4 insulin-associated genes that inversely responded to HFD and ND. Among these, leptin-associated Peli3 (Pellino E3 ubiquitin protein ligase family member 3), Creb1 (cAMP responsive element binding protein 1), and Enpp2 (ectonucleotide pyrophosphatase/phosphodiesterase 2, autotaxin) and insulin-associated Centg1 (AGAP2, ArfGAP with GTPase domain) are reported to play a role either in obesity or colonic diseases. mRNA expression of these genes was validated by RT-qPCR. Our data suggest Peli3, Creb1, Enpp2, and Centg1 as potential early biomarker candidates for obesity-induced pathophysiological changes in the colon. Future studies verifying the function of these candidates are needed for the prevention, early detection, and treatment of colon diseases.
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Affiliation(s)
- Sung-Eun Kim
- Department of Food and Nutrition, Sookmyung Women’s University, Seoul, Republic of Korea
| | - Jinsil Choo
- Department of Life Systems, Sookmyung Women’s University, Seoul, Republic of Korea
| | - Joon Yoon
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea
| | - Jae Ryang Chu
- Department of Life Systems, Sookmyung Women’s University, Seoul, Republic of Korea
| | - Yun Jung Bae
- Division of Food Science and Culinary Arts, Shinhan University, Gyeonggi-do, Republic of Korea
| | - Seungyeoun Lee
- Department of Mathematics and Statistics, Sejong University, Seoul, Republic of Korea
| | - Taesung Park
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, Republic of Korea
- Department of Statistics, Seoul National University, Seoul, Republic of Korea
| | - Mi-Kyung Sung
- Department of Food and Nutrition, Sookmyung Women’s University, Seoul, Republic of Korea
- * E-mail:
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5
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α-Synuclein binds and sequesters PIKE-L into Lewy bodies, triggering dopaminergic cell death via AMPK hyperactivation. Proc Natl Acad Sci U S A 2017; 114:1183-1188. [PMID: 28096359 DOI: 10.1073/pnas.1618627114] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The abnormal aggregation of fibrillar α-synuclein in Lewy bodies plays a critical role in the pathogenesis of Parkinson's disease. However, the molecular mechanisms regulating α-synuclein pathological effects are incompletely understood. Here we show that α-synuclein binds phosphoinositide-3 kinase enhancer L (PIKE-L) in a phosphorylation-dependent manner and sequesters it in Lewy bodies, leading to dopaminergic cell death via AMP-activated protein kinase (AMPK) hyperactivation. α-Synuclein interacts with PIKE-L, an AMPK inhibitory binding partner, and this action is increased by S129 phosphorylation through AMPK and is decreased by Y125 phosphorylation via Src family kinase Fyn. A pleckstrin homology (PH) domain in PIKE-L directly binds α-synuclein and antagonizes its aggregation. Accordingly, PIKE-L overexpression decreases dopaminergic cell death elicited by 1-methyl-4-phenylpyridinium (MPP+), whereas PIKE-L knockdown elevates α-synuclein oligomerization and cell death. The overexpression of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or α-synuclein induces greater dopaminergic cell loss and more severe motor defects in PIKE-KO and Fyn-KO mice than in wild-type mice, and these effects are attenuated by the expression of dominant-negative AMPK. Hence, our findings demonstrate that α-synuclein neutralizes PIKE-L's neuroprotective actions in synucleinopathies, triggering dopaminergic neuronal death by hyperactivating AMPK.
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6
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Hu X, Zhang Q, Zheng J, Kong W, Zhang HH, Zeng TS, Zhang JY, Min J, Wu C, Chen LL. Alteration of FXR phosphorylation and sumoylation in liver in the development of adult catch-up growth. Exp Biol Med (Maywood) 2016; 242:297-304. [PMID: 27190252 DOI: 10.1177/1535370216641788] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Catch-up growth in adult, is increasingly recognized as an important causative factor for the extremely prevalent insulin resistance-related diseases especially in developing countries/territories. We aimed to investigate the alteration of bile acids level, phosphorylation and sumoylation of its interacting protein, bile acid receptor/farnesoid X receptor and their downstream signaling pathway, as well as insulin sensitivity and lipid profile in catch-up growth in adult rats. Male Sprague-Dawley rats were randomly allocated into four groups for two sampling points: caloric restriction group, catch-up growth in adult refed with normal chow and their normal chow controls for four or eight weeks (N4, N8 individually).We found that total serum bile acids and farnesoid X receptor phosphorylation increased without significant changes in farnesoid X receptor sumoylation and its downstream small heterodimer partner expression at the end of caloric restriction stage, while the visceral fat decreased and insulin resistance never occurred in these animals; After refeeding, total serum bile acids, farnesoid X receptor phosphorylation and sumoylation, as well as Cyp7a1, SREBP-1c mRNA levels were higher with significant decrease in small heterodimer partner expression, which is associated fat accumulation, and drastic insulin resistance in whole body and skeletal muscle. Our findings demonstrated that the fat accumulation and insulin resistance are associated with increases of bile acids, alteration of farnesoid X receptor phosphorylation, and sumoylation and its downstream signaling pathway. These changes of bile acids, farnesoid X receptor phosphorylation and sumoylation, as well as their downstream signaling might be of importance in the etiology of fat accumulation and insulin resistance in catch-up growth in adult.
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Affiliation(s)
- Xiang Hu
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qiao Zhang
- 2 Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Juan Zheng
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Wen Kong
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Hao-Hao Zhang
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.,3 Department of Endocrinology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Tian-Shu Zeng
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jiao-Yue Zhang
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Jie Min
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chaodong Wu
- 4 Department of Nutrition and Food Science, Texas A&M University, College Station, Texas 77843, USA
| | - Lu-Lu Chen
- 1 Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
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7
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Kim JE, Roh E, Lee MH, Yu DH, Kim DJ, Lim TG, Jung SK, Peng C, Cho YY, Dickinson S, Alberts D, Bowden GT, Einspahr J, Stratton SP, Curiel-Lewandrowski C, Bode AM, Lee KW, Dong Z. Fyn is a redox sensor involved in solar ultraviolet light-induced signal transduction in skin carcinogenesis. Oncogene 2015; 35:4091-101. [PMID: 26686094 PMCID: PMC4916055 DOI: 10.1038/onc.2015.471] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 09/15/2015] [Accepted: 11/10/2015] [Indexed: 12/21/2022]
Abstract
Solar ultraviolet (UV) light is a major etiological factor in skin carcinogenesis, with solar UV-stimulated signal transduction inducing pathological changes and skin damage. The primary sensor of solar UV-induced cellular signaling has not been identified. We use an experimental system of solar simulated light (SSL) to mimic solar UV and we demonstrate that Fyn is a primary redox sensor involved in SSL-induced signal transduction. Reactive oxygen species (ROS) generated by SSL exposure directly oxidize Cys488 of Fyn, resulting in increased Fyn kinase activity. Fyn oxidation was increased in mouse skin after SSL exposure, and Fyn knockout (Fyn−/−) mice formed larger and more tumors compared to Fyn wildtype mice when exposed to SSL for an extended period of time. Murine embryonic fibroblasts (MEFs) lacking Fyn as well as cells in which Fyn expression was knocked down were resistant to SSL-induced apoptosis. Furthermore, cells expressing mutant Fyn (C448A) were resistant to SSL-induced apoptosis. These findings suggest that Fyn acts as a regulatory nexus between solar UV, ROS and signal transduction during skin carcinogenesis.
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Affiliation(s)
- J-E Kim
- The Hormel Institute, University of Minnesota, Austin, MN, USA.,Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.,Advanced Institutes of Convergence Technology, Seoul National University, Suwon, Gyeonggi-do, Republic of Korea
| | - E Roh
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - M H Lee
- The Hormel Institute, University of Minnesota, Austin, MN, USA.,China-US Hormel Cancer Institute, Zhenzhou, Henan, China
| | - D H Yu
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - D J Kim
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - T-G Lim
- The Hormel Institute, University of Minnesota, Austin, MN, USA.,Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.,Advanced Institutes of Convergence Technology, Seoul National University, Suwon, Gyeonggi-do, Republic of Korea.,Division of Strategic Food Research, Korea Food Research Institute, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - S K Jung
- The Hormel Institute, University of Minnesota, Austin, MN, USA.,Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.,Division of Strategic Food Research, Korea Food Research Institute, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - C Peng
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - Y-Y Cho
- The Hormel Institute, University of Minnesota, Austin, MN, USA.,College of Pharmacy, The Catholic University of Korea, Bucheon-si, Gyeonggi-do, Republic of Korea
| | - S Dickinson
- University of Arizona Cancer Center, Tucson, AZ, USA
| | - D Alberts
- University of Arizona Cancer Center, Tucson, AZ, USA
| | - G T Bowden
- University of Arizona Cancer Center, Tucson, AZ, USA
| | - J Einspahr
- University of Arizona Cancer Center, Tucson, AZ, USA
| | - S P Stratton
- University of Arizona Cancer Center, Tucson, AZ, USA
| | | | - A M Bode
- The Hormel Institute, University of Minnesota, Austin, MN, USA
| | - K W Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea.,Advanced Institutes of Convergence Technology, Seoul National University, Suwon, Gyeonggi-do, Republic of Korea
| | - Z Dong
- The Hormel Institute, University of Minnesota, Austin, MN, USA
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8
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Zhang S, Qi Q, Chan CB, Zhou W, Chen J, Luo HR, Appin C, Brat DJ, Ye K. Fyn-phosphorylated PIKE-A binds and inhibits AMPK signaling, blocking its tumor suppressive activity. Cell Death Differ 2015; 23:52-63. [PMID: 26001218 DOI: 10.1038/cdd.2015.66] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/16/2015] [Accepted: 04/22/2015] [Indexed: 01/03/2023] Open
Abstract
The AMP-activated protein kinase, a key regulator of energy homeostasis, has a critical role in metabolic disorders and cancers. AMPK is mainly regulated by cellular AMP and phosphorylation by upstream kinases. Here, we show that PIKE-A binds to AMPK and blocks its tumor suppressive actions, which are mediated by tyrosine kinase Fyn. PIKE-A directly interacts with AMPK catalytic alpha subunit and impairs T172 phosphorylation, leading to repression of its kinase activity on the downstream targets. Mutation of Fyn phosphorylation sites on PIKE-A, depletion of Fyn, or pharmacological inhibition of Fyn blunts the association between PIKE-A and AMPK, resulting in loss of its inhibitory effect on AMPK. Cell proliferation and oncogenic assays demonstrate that PIKE-A antagonizes tumor suppressive actions of AMPK. In human glioblastoma samples, PIKE-A expression inversely correlates with the p-AMPK levels, supporting that PIKE-A negatively regulates AMPK activity in cancers. Thus, our findings provide additional layer of molecular regulation of the AMPK signaling pathway in cancer progression.
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Affiliation(s)
- S Zhang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, 30322 GA, USA
| | - Q Qi
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, 30322 GA, USA
| | - C B Chan
- Department of Physiology, The University of Oklahoma Health Sciences Center, Oklahoma City, 73104 OK, USA
| | - W Zhou
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, 30322 GA, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, 30322 GA, USA
| | - J Chen
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, 30322 GA, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, 30322 GA, USA
| | - H R Luo
- Department of Pathology and Lab Medicine, Harvard Medical School and Children's Hospital, Boston, 02115 MA, USA
| | - C Appin
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, 30322 GA, USA
| | - D J Brat
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, 30322 GA, USA
| | - K Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, 30322 GA, USA.,Winship Cancer Institute, Emory University School of Medicine, Atlanta, 30322 GA, USA
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9
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Chan CB, Tse MCL, Liu X, Zhang S, Schmidt R, Otten R, Liu L, Ye K. Activation of muscular TrkB by its small molecular agonist 7,8-dihydroxyflavone sex-dependently regulates energy metabolism in diet-induced obese mice. ACTA ACUST UNITED AC 2015; 22:355-68. [PMID: 25754472 DOI: 10.1016/j.chembiol.2015.02.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/30/2015] [Accepted: 02/05/2015] [Indexed: 12/22/2022]
Abstract
Chronic activation of brain-derived neurotrophic factor (BDNF) receptor TrkB is a potential method to prevent development of obesity, but the short half-life and nonbioavailable nature of BDNF hampers validation of the hypothesis. We report here that activation of muscular TrkB by the BDNF mimetic, 7,8-dihydroxyflavone (7,8-DHF), is sufficient to protect the development of diet-induced obesity in female mice. Using in vitro and in vivo models, we found that 7,8-DHF treatment enhanced the expression of uncoupling protein 1 (UCP1) and AMP-activated protein kinase (AMPK) activity in skeletal muscle, which resulted in increased systemic energy expenditure, reduced adiposity, and improved insulin sensitivity in female mice fed a high-fat diet. This antiobesity activity of 7,8-DHF is muscular TrkB-dependent as 7,8-DHF cannot mitigate diet-induced obesity in female muscle-specific TrkB knockout mice. Hence, our data reveal that chronic activation of muscular TrkB is useful in alleviating obesity and its complications.
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Affiliation(s)
- Chi Bun Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA; Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
| | - Margaret Chui Ling Tse
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA; Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
| | - Xia Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Shuai Zhang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Robin Schmidt
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Reed Otten
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Liegang Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science & Technology, 13 Hangkong Road, Wuhan, 430030, P.R. China
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA.
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Sarvas JL, Otis JS, Khaper N, Lees SJ. Voluntary physical activity prevents insulin resistance in a tissue specific manner. Physiol Rep 2015; 3:3/2/e12277. [PMID: 25713323 PMCID: PMC4393189 DOI: 10.14814/phy2.12277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Physical inactivity and a sedentary lifestyle are risk factors for the development of type 2 diabetes. Here, we identified the effects 8 weeks of voluntary physical activity had on the prevention of insulin resistance in mouse skeletal muscles and liver (a hallmark of T2D). To do this, 8 week old C57BL/6J mice with (RUN) and without (SED) voluntary access to running wheels were fed a standard rodent chow ad libitum for 8 weeks. In the liver, there was a 2.5-fold increase in insulin stimulated AktSER473 phosphorylation, and a threefold increase in insulin-stimulated (0.5 U/kg) GSK3βSER9 phosphorylation in RUN compared to SED mice. Although not induced in skeletal muscles, there was a twofold increase in SOCS3 expression in SED compared to RUN mice in the liver. There was no difference in the glucose tolerance test between groups. This study was the first to show differences in liver insulin sensitivity after 8 weeks of voluntary physical activity, and increased SOCS3 expression in the liver of sedentary mice compared to active mice. These findings demonstrate that even in young mice that would normally be considered healthy, the lack of physical activity leads to insulin resistance representing the initial pathogenesis of impaired glucose metabolism leading to type 2 diabetes.
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Affiliation(s)
- Jessica L Sarvas
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Jeffrey S Otis
- Department of Kinesiology and Health, Georgia State University, Atlanta, Georgia, Canada
| | - Neelam Khaper
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada
| | - Simon J Lees
- Medical Sciences Division, Northern Ontario School of Medicine, Thunder Bay, Ontario, Canada Department of Biology, Lakehead University, Thunder Bay, Ontario, Canada Health and Exercise Science, Colorado State University, Fort Collins, Colorado, Canada
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11
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The PIKE homolog Centaurin gamma regulates developmental timing in Drosophila. PLoS One 2014; 9:e97332. [PMID: 24845618 PMCID: PMC4028201 DOI: 10.1371/journal.pone.0097332] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/17/2014] [Indexed: 12/30/2022] Open
Abstract
Phosphoinositide-3-kinase enhancer (PIKE) proteins encoded by the PIKE/CENTG1 gene are members of the gamma subgroup of the Centaurin superfamily of small GTPases. They are characterized by their chimeric protein domain architecture consisting of a pleckstrin homology (PH) domain, a GTPase-activating (GAP) domain, Ankyrin repeats as well as an intrinsic GTPase domain. In mammals, three PIKE isoforms with variations in protein structure and subcellular localization are encoded by the PIKE locus. PIKE inactivation in mice results in a broad range of defects, including neuronal cell death during brain development and misregulation of mammary gland development. PIKE -/- mutant mice are smaller, contain less white adipose tissue, and show insulin resistance due to misregulation of AMP-activated protein kinase (AMPK) and insulin receptor/Akt signaling. here, we have studied the role of PIKE proteins in metabolic regulation in the fly. We show that the Drosophila PIKE homolog, ceng1A, encodes functional GTPases whose internal GAP domains catalyze their GTPase activity. To elucidate the biological function of ceng1A in flies, we introduced a deletion in the ceng1A gene by homologous recombination that removes all predicted functional PIKE domains. We found that homozygous ceng1A mutant animals survive to adulthood. In contrast to PIKE -/- mouse mutants, genetic ablation of Drosophila ceng1A does not result in growth defects or weight reduction. Although metabolic pathways such as insulin signaling, sensitivity towards starvation and mobilization of lipids under high fed conditions are not perturbed in ceng1A mutants, homozygous ceng1A mutants show a prolonged development in second instar larval stage, leading to a late onset of pupariation. In line with these results we found that expression of ecdysone inducible genes is reduced in ceng1A mutants. Together, we propose a novel role for Drosophila Ceng1A in regulating ecdysone signaling-dependent second to third instar larval transition.
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12
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PIKE is essential for oligodendroglia development and CNS myelination. Proc Natl Acad Sci U S A 2014; 111:1993-8. [PMID: 24449917 DOI: 10.1073/pnas.1318185111] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Oligodendrocyte (OL) differentiation and myelin development are complex events regulated by numerous signal transduction factors. Here, we report that phosphoinositide-3 kinase enhancer L (PIKE-L) is required for OL development and myelination. PIKE-L expression is up-regulated when oligodendrocyte progenitor cells commit to differentiation. Conversely, depleting phosphoinositide-3 kinase enhancer (PIKE) expression by shRNA prevents oligodendrocyte progenitor cell differentiation. In both conventional PIKE knockout (PIKE(-/-)) and OL-specific PIKE knockout mice, the number of OLs is reduced in the corpus callosum. PIKE(-/-) OLs also display defects when forming myelin sheath on neuronal axons during neonatal development, which is partially rescued when PTEN is ablated. In addition, Akt/mTOR signaling is impaired in OL-enriched tissues of the PIKE(-/-) mutant, leading to reduced expression of critical proteins for myelin development and hypomyelination. Moreover, myelin repair of lysolecithin-induced lesions is delayed in PIKE(-/-) brain. Thus, PIKE plays pivotal roles to advance OL development and myelinogenesis through Akt/mTOR activation.
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Qi Q, Ye K. The roles of PIKE in tumorigenesis. Acta Pharmacol Sin 2013; 34:991-7. [PMID: 23770988 PMCID: PMC3733165 DOI: 10.1038/aps.2013.71] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 04/28/2013] [Indexed: 01/22/2023] Open
Abstract
Tumorigenesis is the process by which normal cells evolve the capacity to evade and overcome the constraints usually placed upon their growth and survival. To ensure the integrity of organs and tissues, the balance of cell proliferation and cell death is tightly maintained. The proteins controlling this balance are either considered oncogenes, which promote tumorigenesis, or tumor suppressors, which prevent tumorigenesis. Phosphoinositide 3-kinase enhancer (PIKE) is a family of GTP-binding proteins that possess anti-apoptotic functions and play an important role in the central nervous system. Notably, accumulating evidence suggests that PIKE is a proto-oncogene involved in tumor progression. The PIKE gene (CENTG1) is amplified in a variety of human cancers, leading to the resistance against apoptosis and the enhancement of invasion. In this review, we will summarize the functions of PIKE proteins in tumorigenesis and discuss their potential implications in cancer therapy.
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Chan CB, Chen Y, Liu X, Papale L, Escayg A, Mei L, Ye K. Essential role of PIKE GTPases in neuronal protection against excitotoxic insults. Adv Biol Regul 2013; 52:66-76. [PMID: 21925531 DOI: 10.1016/j.advenzreg.2011.09.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 09/06/2011] [Indexed: 11/19/2022]
Affiliation(s)
- Chi Bun Chan
- Department of Pathology and Laboratory Medicine, USA
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15
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Abstract
Fyn is a tyrosine kinase with multiple roles in a variety of cellular processes. Here we report that Fyn is a new kinase involved in adipocyte differentiation. Elevated Fyn protein is detected specifically in the adipocytes of obese mice. Moreover, Fyn expression increases progressively in 3T3-L1 cells during in vitro adipogenesis, which correlates with its kinase activity. Inhibition of Fyn by either genetic or pharmacological manipulation restrains the 3T3-L1 preadipocytes from fully differentiating into mature adipocytes. Mechanistically, Fyn regulates the activity of the adipogenic transcription factor signal transducer and activator of transcription 5a (STAT5a) through enhancing its interaction with the GTPase phosphoinositide 3-kinase enhancer A (PIKE-A). The STAT5a activity is therefore reduced in Fyn- or PIKE-ablated adipose tissues, leading to diminished expression of adipogenic markers and adipocyte differentiation. Our data thus demonstrate a novel functional interaction between Fyn, PIKE-A, and STAT5a in mediating adipogenesis.
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16
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Basseri S, Lhoták Š, Fullerton MD, Palanivel R, Jiang H, Lynn EG, Ford RJ, Maclean KN, Steinberg GR, Austin RC. Loss of TDAG51 results in mature-onset obesity, hepatic steatosis, and insulin resistance by regulating lipogenesis. Diabetes 2013; 62:158-69. [PMID: 22961087 PMCID: PMC3526025 DOI: 10.2337/db12-0256] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Regulation of energy metabolism is critical for the prevention of obesity, diabetes, and hepatic steatosis. Here, we report an important role for the pleckstrin homology-related domain family member, T-cell death-associated gene 51 (TDAG51), in the regulation of energy metabolism. TDAG51 expression was examined during adipocyte differentiation. Adipogenic potential of preadipocytes with knockdown or absence of TDAG51 was assessed. Weight gain, insulin sensitivity, metabolic rate, and liver lipid content were also compared between TDAG51-deficient (TDAG51(-/-)) and wild-type mice. In addition to its relatively high expression in liver, TDAG51 was also present in white adipose tissue (WAT). TDAG51 was downregulated during adipogenesis, and TDAG51(-/-) preadipocytes exhibited greater lipogenic potential. TDAG51(-/-) mice fed a chow diet exhibited greater body and WAT mass, had reduced energy expenditure, displayed mature-onset insulin resistance (IR), and were predisposed to hepatic steatosis. TDAG51(-/-) mice had increased hepatic triglycerides and SREBP-1 target gene expression. Furthermore, TDAG51 expression was inversely correlated with fatty liver in multiple mouse models of hepatic steatosis. Taken together, our findings suggest that TDAG51 is involved in energy homeostasis at least in part by regulating lipogenesis in liver and WAT, and hence, may constitute a novel therapeutic target for the treatment of obesity and IR.
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Affiliation(s)
- Sana Basseri
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Hamilton Centre for Kidney Research, St. Joseph’s Healthcare Hamilton, Hamilton, Ontario, Canada
| | - Šárka Lhoták
- Hamilton Centre for Kidney Research, St. Joseph’s Healthcare Hamilton, Hamilton, Ontario, Canada
| | - Morgan D. Fullerton
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Rengasamy Palanivel
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Hua Jiang
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Edward G. Lynn
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Hamilton Centre for Kidney Research, St. Joseph’s Healthcare Hamilton, Hamilton, Ontario, Canada
| | - Rebecca J. Ford
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Kenneth N. Maclean
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado
| | - Gregory R. Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Richard C. Austin
- Division of Nephrology, Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Hamilton Centre for Kidney Research, St. Joseph’s Healthcare Hamilton, Hamilton, Ontario, Canada
- Corresponding author: Richard C. Austin,
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Dietary strawberry powder reduces blood glucose concentrations in obese and lean C57BL/6 mice, and selectively lowers plasma C-reactive protein in lean mice. Br J Nutr 2012; 108:1789-99. [PMID: 22293281 DOI: 10.1017/s0007114512000037] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The purpose of the present study was to test the anti-inflammatory and blood glucose (BG)-regulating capacity of strawberries in a mouse model of diet-induced obesity. A total of thirty-six male C57BL/6J mice were randomly divided into four groups (nine mice per group). Mice were fed a low-fat diet (LF, 13 % fat), the LF supplemented with 2·6 % freeze-dried strawberry powder (LFSB), a high-fat diet (HF, 44 % fat) or the HF supplemented with 2·6 % strawberry powder (HFSB). Blood samples were collected to measure BG, inflammation and systemic markers for endocrine function of pancreas and adipose tissue. Splenocytes were harvested at the end of the study and activated with either anti-cluster of differentiation (CD) 3/anti-CD28 antibodies or lipopolysaccharide to test immune responsiveness. The HF increased non-fasted BG, insulin, soluble intracellular adhesion molecule-1, E-selectin, leptin, resistin and plasminogen activator protein-1 (P < 0·05). High dietary fat decreased IL-4 production from activated splenocytes (P < 0·05). BG concentrations were lower in the mice supplemented with SB (10·64 mmol/l) compared to the non-supplemented mice (11·37 mmol/l; P = 0·0022). BG values were approximately 6·5 % lower in the supplemented mice. Additionally, SB lowered plasma C-reactive protein in the LFSB group compared to the other three groups (P < 0·05). The dietary intake of SB approximated one human serving of strawberries. These results, although modest, support a promising role for dietary strawberries in reducing the risks associated with obesity and diabetes, and regulating the levels of inflammatory markers in non-obese individuals.
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Chan CB, Ye K. Phosphoinositide 3-kinase enhancer (PIKE) in the brain: is it simply a phosphoinositide 3-kinase/Akt enhancer? Rev Neurosci 2012; 23:153-61. [PMID: 22499674 DOI: 10.1515/revneuro-2011-0066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 12/12/2011] [Indexed: 02/06/2023]
Abstract
Since its discovery in 2000, phosphoinositide 3-kinase enhancer (PIKE) has been recognized as a class of GTPase that controls the enzymatic activities of phosphoinositide 3-kinase (PI3K) and Akt in the central nervous system (CNS). However, recent studies suggest that PIKEs are not only enhancers to PI3K/Akt but also modulators to other kinases including insulin receptor tyrosine kinase and focal adhesion kinases. Moreover, they regulate transcription factors such as signal transducer and activator of transcription and nuclear factor κB. Indeed, PIKE proteins participate in multiple cellular processes including control of cell survival, brain development, memory formation, gene transcription, and metabolism. In this review, we have summarized the functions of PIKE proteins in CNS and discussed their potential implications in various neurological disorders.
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Affiliation(s)
- Chi Bun Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA.
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Abstract
Studies of epilepsy have mainly focused on the membrane proteins that control neuronal excitability. Recently, attention has been shifting to intracellular proteins and their interactions, signaling cascades and feedback regulation as they relate to epilepsy. The mTOR (mammalian target of rapamycin) signal transduction pathway, especially, has been suggested to play an important role in this regard. These pathways are involved in major physiological processes as well as in numerous pathological conditions. Here, involvement of the mTOR pathway in epilepsy will be reviewed by presenting; an overview of the pathway, a brief description of key signaling molecules, a summary of independent reports and possible implications of abnormalities of those molecules in epilepsy, a discussion of the lack of experimental data, and questions raised for the understanding its epileptogenic mechanism.
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Affiliation(s)
- Chang Hoon Cho
- Epilepsy Research Laboratory Department of Pediatrics Children's Hospital of Philadelphia, Pennsylvania 19104, USA.
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Phosphoinositide 3-kinase enhancer regulates neuronal dendritogenesis and survival in neocortex. J Neurosci 2011; 31:8083-92. [PMID: 21632930 DOI: 10.1523/jneurosci.1129-11.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Phosphoinositide 3-kinase enhancer (PIKE) binds and enhances phosphatidylinositol 3-kinase (PI3K)/Akt activities. However, its physiological functions in brain have never been explored. Here we show that PIKE is important in regulating the neuronal survival and development of neocortex. During development, enhanced apoptosis is observed in the ventricular zone of PIKE knock-out (PIKE(-/-)) cortex. Moreover, PIKE(-/-) neurons show reduced dendritic complexity, dendritic branch length, and soma size. These defects are due to the reduced PI3K/Akt activities in PIKE(-/-) neurons, as the impaired dendritic arborization can be rescued when PI3K/Akt cascade is augmented in vitro or in PIKE(-/-)PTEN(-/-) double-knock-out mice. Interestingly, PIKE(-/-) mice display behavioral abnormality in locomotion and spatial navigation. Because of the diminished PI3K/Akt activities, PIKE(-/-) neurons are more vulnerable to glutamate- or stroke-induced neuronal cell death. Together, our data established the critical role of PIKE in regulating neuronal survival and development by substantiating the PI3K/Akt pathway.
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The association of phosphoinositide 3-kinase enhancer A with hepatic insulin receptor enhances its kinase activity. EMBO Rep 2011; 12:847-54. [PMID: 21720388 DOI: 10.1038/embor.2011.108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 05/11/2011] [Accepted: 05/16/2011] [Indexed: 12/31/2022] Open
Abstract
Dysfunction of hepatic insulin receptor tyrosine kinase (IRTK) causes the development of type 2 diabetes. However, the molecular mechanism regulating IRTK activity in the liver remains poorly understood. Here, we show that phosphoinositide 3-kinase enhancer A (PIKE-A) is a new insulin-dependent enhancer of hepatic IRTK. Liver-specific Pike-knockout (LPKO) mice display glucose intolerance with impaired hepatic insulin sensitivity. Specifically, insulin-provoked phosphoinositide 3-kinase/Akt signalling is diminished in the liver of LPKO mice, leading to the failure of insulin-suppressed gluconeogenesis and hyperglycaemia. Thus, hepatic PIKE-A has a key role in mediating insulin signal transduction and regulating glucose homeostasis in the liver.
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Chan CB, Ye K. What we have learnt about PIKE from the knockout mice. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2011; 2:228-239. [PMID: 22003435 PMCID: PMC3193289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 05/28/2011] [Indexed: 05/31/2023]
Abstract
Phosphoinositide 3-kinase enhancer (PIKE) is a group of GTPase that belongs to the centaurin superfamily. These proteins have been discovered for more than a decade but our understandings on their functions are still limited. Studies from our research group and others have revealed some of their functions in a cellular context but their roles in organ development or systemic homeostasis just begin to unveil. The generation of PIKE knockout mice thus provides the valuable model to delineate the physiological roles of PIKE. In addition to being a PI3K/Akt enhancer, phenotypic characterization of the PIKE knockout mice demonstrates that the proteins are involved in multiple signaling cascades including Janus kinase (JAK)/ Signal Transducer and Activator of Transcription (STAT), AMP-activated protein kinase (AMPK)/Acetyl-CoA carboxylase (ACC) and insulin receptor (IR)/Akt. In this article, we will review the current findings from the PIKE knockout mice studies and will discuss how these in vivo observations lead to the identifications of novel signaling cascades regulated by PIKE.
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Affiliation(s)
- Chi Bun Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine Atlanta, GA USA
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