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Haugg E, Borner J, Stalder G, Kübber‐Heiss A, Giroud S, Herwig A. Comparative transcriptomics of the garden dormouse hypothalamus during hibernation. FEBS Open Bio 2024; 14:241-257. [PMID: 37925593 PMCID: PMC10839406 DOI: 10.1002/2211-5463.13731] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/25/2023] [Accepted: 11/02/2023] [Indexed: 11/06/2023] Open
Abstract
Torpor or heterothermy is an energy-saving mechanism used by endotherms to overcome harsh environmental conditions. During winter, the garden dormouse (Eliomys quercinus) hibernates with multiday torpor bouts and body temperatures of a few degrees Celsius, interrupted by brief euthermic phases. This study investigates gene expression within the hypothalamus, the key brain area controlling energy balance, adding information on differential gene expression potentially relevant to orchestrate torpor. A de novo assembled transcriptome of the hypothalamus was generated from garden dormice hibernating under constant darkness without food and water at 5 °C. Samples were collected during early torpor, late torpor, and interbout arousal. During early torpor, 765 genes were differentially expressed as compared with interbout arousal. Twenty-seven pathways were over-represented, including pathways related to hemostasis, extracellular matrix organization, and signaling of small molecules. Only 82 genes were found to be differentially expressed between early and late torpor, and no pathways were over-represented. During late torpor, 924 genes were differentially expressed relative to interbout arousal. Despite the high number of differentially expressed genes, only 10 pathways were over-represented. Of these, eight were also observed to be over-represented when comparing early torpor and interbout arousal. Our results are largely consistent with previous findings in other heterotherms. The addition of a transcriptome of a novel species may help to identify species-specific and overarching torpor mechanisms through future species comparisons.
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Affiliation(s)
- Elena Haugg
- Institute of NeurobiologyUlm UniversityGermany
| | - Janus Borner
- Sackler Institute for Comparative GenomicsAmerican Museum of Natural HistoryNew YorkNYUSA
| | - Gabrielle Stalder
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife EcologyUniversity of Veterinary MedicineViennaAustria
| | - Anna Kübber‐Heiss
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife EcologyUniversity of Veterinary MedicineViennaAustria
| | - Sylvain Giroud
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife EcologyUniversity of Veterinary MedicineViennaAustria
- Energetics Lab, Department of BiologyNorthern Michigan UniversityMarquetteMIUSA
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2
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Nunes LGA, Cain A, Comyns C, Hoffmann PR, Krahn N. Deciphering the Role of Selenoprotein M. Antioxidants (Basel) 2023; 12:1906. [PMID: 38001759 PMCID: PMC10668967 DOI: 10.3390/antiox12111906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/20/2023] [Accepted: 10/21/2023] [Indexed: 11/26/2023] Open
Abstract
Selenocysteine (Sec), the 21st amino acid, is structurally similar to cysteine but with a sulfur to selenium replacement. This single change retains many of the chemical properties of cysteine but often with enhanced catalytic and redox activity. Incorporation of Sec into proteins is unique, requiring additional translation factors and multiple steps to insert Sec at stop (UGA) codons. These Sec-containing proteins (selenoproteins) are found in all three domains of life where they often are involved in cellular homeostasis (e.g., reducing reactive oxygen species). The essential role of selenoproteins in humans requires us to maintain appropriate levels of selenium, the precursor for Sec, in our diet. Too much selenium is also problematic due to its toxic effects. Deciphering the role of Sec in selenoproteins is challenging for many reasons, one of which is due to their complicated biosynthesis pathway. However, clever strategies are surfacing to overcome this and facilitate production of selenoproteins. Here, we focus on one of the 25 human selenoproteins, selenoprotein M (SELENOM), which has wide-spread expression throughout our tissues. Its thioredoxin motif suggests oxidoreductase function; however, its mechanism and functional role(s) are still being uncovered. Furthermore, the connection of both high and low expression levels of SELENOM to separate diseases emphasizes the medical application for studying the role of Sec in this protein. In this review, we aim to decipher the role of SELENOM through detailing and connecting current evidence. With multiple proposed functions in diverse tissues, continued research is still necessary to fully unveil the role of SELENOM.
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Affiliation(s)
- Lance G. A. Nunes
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813-5525, USA
| | - Antavius Cain
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
| | - Cody Comyns
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511-4902, USA
| | - Peter R. Hoffmann
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813-5525, USA
| | - Natalie Krahn
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511-4902, USA
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Wang Y, Yang J, Wang Y, Chen Y, Wang Y, Kuang H, Feng X. Upregulation of TXNIP contributes to granulosa cell dysfunction in polycystic ovary syndrome via activation of the NLRP3 inflammasome. Mol Cell Endocrinol 2023; 561:111824. [PMID: 36450326 DOI: 10.1016/j.mce.2022.111824] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/22/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022]
Abstract
Polycystic ovary syndrome (PCOS) is a complex endocrine disease. Thioredoxin-interacting protein (TXNIP) promotes oxidative stress and triggers inflammation. Herein, we investigated the role and potential mechanism of TXNIP in PCOS. In a mouse model of dehydroepiandrosterone (DHEA)-induced PCOS, we found that TXNIP was upregulated in the ovaries, especially in granulosa cells (GCs). TXNIP was also upregulated in testosterone (T)-treated GCs in vitro. Knockdown of TXNIP by lentivirus-constructed shRNA attenuated T-induced GC injury and oxidative stress, as well as inflammation and the NLRP3 inflammasome. The mechanism by which TXNIP promotes inflammation may involve TXNIP dissociation from the TXNIP-TRX complex and binding to NLRP3 to form the inflammasome. Additionally, we verified that knockdown of TXNIP ameliorated ovarian injury and inflammation in mice with DHEA-induced PCOS in vivo. Collectively, we demonstrated that TXNIP is involved in GC inflammation by promoting NLRP3 inflammasome activation in PCOS.
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Affiliation(s)
- Ying Wang
- The Second Department of Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Jiyu Yang
- Graduate School, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yu Wang
- Graduate School, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yao Chen
- Graduate School, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Yiran Wang
- School of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Hongying Kuang
- The Second Department of Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, China.
| | - Xiaoling Feng
- The Second Department of Gynecology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, China.
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Ameliorative effects of bromelain on aluminum-induced Alzheimer's disease in rats through modulation of TXNIP pathway. Int J Biol Macromol 2023; 227:1119-1131. [PMID: 36462588 DOI: 10.1016/j.ijbiomac.2022.11.291] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/01/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022]
Abstract
Alzheimer's disease (AD) is known as "type 3 diabetes". As thioredoxin binding protein (TXNIP) has been shown to be involved in brain insulin resistance, the present study evaluated the roles of TXNIP, phospho-insulin receptor substrate 1 (P-IRS-1), and phosphatidyl inositol-3 kinase (PI3K) in the pathogenesis of AD. The potential ameliorative effect of bromelain compared to donepezil was evaluated in an aluminum chloride (AlCl3)-induced AD in rats. Behavioral tests demonstrated similar improvements in exploratory activity, cognitive and spatial memory functions, anxiety, and depression levels between rats treated with bromelain and donepezil. Donepezil was superior to bromelain in improving locomotor activity. Histopathological examinations demonstrated neuronal degeneration in the AlCl3 group that was almost normalized by bromelain and donepezil. Moreover, there was deposition of amyloid plaques in the AlCl3 group that was improved by bromelain and donepezil. Acetylcholine esterase levels were significantly increased in rats treated with AlCl3 group and significantly decreased in rats treated with bromelain and donepezil. Furthermore, AlCl3 group showed a significantly increased TXNIP and P-IRS1 and a significantly reduced PI3K levels. These effects were ameliorated by bromelain and donepezil treatment. The present study demonstrates a previously unreported modulatory effect of bromelain on the TXNIP/P-IRS-1/PI3K axis in AD model.
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5
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Jiang N, Liu J, Guan C, Ma C, An J, Tang X. Thioredoxin-interacting protein: A new therapeutic target in bone metabolism disorders? Front Immunol 2022; 13:955128. [PMID: 36059548 PMCID: PMC9428757 DOI: 10.3389/fimmu.2022.955128] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/28/2022] [Indexed: 12/05/2022] Open
Abstract
Target identification is essential for developing novel therapeutic strategies in diseases. Thioredoxin-interacting protein (TXNIP), also known as thioredoxin-binding protein-2, is a member of the α-arrestin protein family and is regulated by several cellular stress factors. TXNIP overexpression coupled with thioredoxin inhibits its antioxidant functions, thereby increasing oxidative stress. TXNIP is directly involved in inflammatory activation by interacting with Nod-like receptor protein 3 inflammasome. Bone metabolic disorders are associated with aging, oxidative stress, and inflammation. They are characterized by an imbalance between bone formation involving osteoblasts and bone resorption by osteoclasts, and by chondrocyte destruction. The role of TXNIP in bone metabolic diseases has been extensively investigated. Here, we discuss the roles of TXNIP in the regulatory mechanisms of transcription and protein levels and summarize its involvement in bone metabolic disorders such as osteoporosis, osteoarthritis, and rheumatoid arthritis. TXNIP is expressed in osteoblasts, osteoclasts, and chondrocytes and affects the differentiation and functioning of skeletal cells through both redox-dependent and -independent regulatory mechanisms. Therefore, TXNIP is a potential regulatory and functional factor in bone metabolism and a possible new target for the treatment of bone metabolism-related diseases.
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Affiliation(s)
- Na Jiang
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
| | - Jinjin Liu
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Conghui Guan
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Chengxu Ma
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
| | - Jinyang An
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
| | - Xulei Tang
- The First Clinical Medical College of Lanzhou University, Lanzhou, China
- Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, China
- *Correspondence: Xulei Tang,
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Blood DNA methylation at TXNIP and glycemic changes in response to weight-loss diet interventions: the POUNDS lost trial. Int J Obes (Lond) 2022; 46:1122-1127. [PMID: 35165382 PMCID: PMC9156542 DOI: 10.1038/s41366-022-01084-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/24/2022] [Accepted: 01/28/2022] [Indexed: 01/01/2023]
Abstract
Background: Methods: Results: Conclusions:
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7
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Perrone L, Valente M. The Emerging Role of Metabolism in Brain-Heart Axis: New Challenge for the Therapy and Prevention of Alzheimer Disease. May Thioredoxin Interacting Protein (TXNIP) Play a Role? Biomolecules 2021; 11:1652. [PMID: 34827650 PMCID: PMC8616009 DOI: 10.3390/biom11111652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/02/2021] [Accepted: 11/06/2021] [Indexed: 12/15/2022] Open
Abstract
Alzheimer disease (AD) is the most frequent cause of dementia and up to now there is not an effective therapy to cure AD. In addition, AD onset occurs decades before the diagnosis, affecting the possibility to set up appropriate therapeutic strategies. For this reason, it is necessary to investigate the effects of risk factors, such as cardiovascular diseases, in promoting AD. AD shows not only brain dysfunction, but also alterations in peripheral tissues/organs. Indeed, it exists a reciprocal connection between brain and heart, where cardiovascular alterations participate to AD as well as AD seem to promote cardiovascular dysfunction. In addition, metabolic dysfunction promotes both cardiovascular diseases and AD. In this review, we summarize the pathways involved in the regulation of the brain-heart axis and the effect of metabolism on these pathways. We also present the studies showing the role of the gut microbiota on the brain-heart axis. Herein, we propose recent evidences of the function of Thioredoxin Interacting protein (TXNIP) in mediating the role of metabolism on the brain-heart axis. TXNIP is a key regulator of metabolism at both cellular and body level and it exerts also a pathological function in several cardiovascular diseases as well as in AD.
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Affiliation(s)
- Lorena Perrone
- Department of Advanced Medical and Surgical Sciences, University of Campania Luigi Vanvitelli, 80131 Naples, Italy
| | - Mariarosaria Valente
- Department of Medicine, University of Udine, 33100 Udine, Italy;
- Clinical Neurology Unit, Department of Neuroscience, Azienda Sanitaria Universitaria Friuli Centrale, University Hospital, 33100 Udine, Italy
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Gong T, Hashimoto AC, Sasuclark AR, Khadka VS, Gurary A, Pitts MW. Selenoprotein M Promotes Hypothalamic Leptin Signaling and Thioredoxin Antioxidant Activity. Antioxid Redox Signal 2021; 35:775-787. [PMID: 30648404 PMCID: PMC8617589 DOI: 10.1089/ars.2018.7594] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Aims: Selenoproteins are an essential class of proteins involved in redox signaling and energy metabolism. However, the functions of many selenoproteins are not clearly established. Selenoprotein M (SELENOM), an endoplasmic reticulum (ER)-resident oxidoreductase bearing structural similarity to thioredoxin (TXN), is among those yet to be fully characterized. This protein is highly expressed in hypothalamic regions involved in leptin signaling and has been previously linked to energy metabolism. Herein, we performed a series of studies using in vivo and in vitro models to probe the specific influence of SELENOM on hypothalamic leptin signaling and assess SELENOM-regulated pathways. Innovation and Results: Our initial experiment in vivo demonstrated that (i) leptin promotes hypothalamic expression of SELENOM and (ii) leptin-induced STAT3 phosphorylation is impeded by SELENOM deficiency. Additional in vitro studies using mHypoE-44 immortalized hypothalamic neurons corroborated these findings, as SELENOM deficiency obstructed downstream STAT3 phosphorylation and cytosolic calcium responses evoked by leptin treatment. Correspondingly, SELENOM overexpression enhanced leptin sensitivity. Microarray analysis conducted in parallel on hypothalamic tissue and mHypoE-44 cells revealed multiple genes significantly affected by SELENOM deficiency, including thioredoxin interacting protein, a negative regulator of the TXN system. Further analysis determined that (i) SELENOM itself possesses intrinsic TXN activity and (ii) SELENOM deficiency leads to a reduction in overall TXN activity. Finally, mHypoE-44 cells lacking SELENOM displayed diminished activation of the nuclear factor kappa-light-chain enhancer of activated B-cells (NF-κB) signaling pathway and increased susceptibility to ER stress-mediated cell death. Conclusion: In sum, these findings establish SELENOM as a positive regulator of leptin signaling and TXN antioxidant activity in the hypothalamus. Antioxid. Redox Signal. 35, 775-787.
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Affiliation(s)
- Ting Gong
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, Hawaii, USA
| | - Ann C Hashimoto
- Department of Cell and Molecular Biology, Medical Microbiolgy, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Alexandru R Sasuclark
- Department of Cell and Molecular Biology, Medical Microbiolgy, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Vedbar S Khadka
- Bioinformatics Core in the Department of Complementary and Integrative Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Alexandra Gurary
- Department of Tropical Medicine, Medical Microbiolgy, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Matthew W Pitts
- Department of Cell and Molecular Biology, Medical Microbiolgy, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
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Chu Y, Widjaja J, Hong J, Dolo PR, Zhu X, Yao L. Effect of Sleeve Gastrectomy on Plasma Thioredoxin-Interacting Protein (TXNIP). Obes Surg 2021; 31:4829-4835. [PMID: 34370159 DOI: 10.1007/s11695-021-05649-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 02/03/2023]
Abstract
PURPOSE The mechanism in which bariatric surgery induces diabetes remission is still poorly understood. This study proposes Thioredoxin-interacting protein (TXNIP) as a possible factor for the anti-diabetic mechanism after sleeve gastrectomy (SG). MATERIALS AND METHODS Plasma TXNIP level in obesity patients with diabetes (T2D, N = 20), obesity patients without diabetes (NDO, N = 20), and patients without obesity and diabetes (lean, N = 10) were assessed before surgery and at 1 and 12 months after SG. RESULTS Preoperative TXNIP level was significantly higher in T2D (196.4 ± 76.0 pg/ml) and NDO (149.7 ± 94.1 pg/ml) patients when compared with lean patients (98.7 ± 22.7 pg/ml) (p-value < 0.05). At 1 month and 12 months postoperatively, the TXNIP levels were reduced significantly from the preoperative levels in the T2D and NDO patients (p-value < 0.05). Before surgery, a correlation between TXNIP and fasting blood glucose (FBG) (r2 = 0.1585, p-value = 0.0109), HbA1C (r2 = 0.2120, p-value = 0.0028), and insulin (r2 = 0.1217, p-value = 0.0274) was observed. At 12 months after surgery, the reduction of TXNIP was also correlated with the degree of FBG (r2 = 0.1038, p-value = 0.0426), HbA1C (r2 = 0.2459, p-value = 0.0011), and insulin (r2 = 0.1365, p-value = 0.0190) reduction. CONCLUSION Plasma TXNIP level is elevated in obesity patients with/without diabetes. SG resulted in a significant reduction of plasma TXNIP level which is correlated with the degree of FBG, HbA1C, and insulin reduction. Regulation of TXNIP could be part of the mechanism of diabetes remission after bariatric surgery.
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Affiliation(s)
- Yuxiao Chu
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Jason Widjaja
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Jian Hong
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Ponnie Robertlee Dolo
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Xiaocheng Zhu
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China
| | - Libin Yao
- Department of Gastrointestinal Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, 221002, People's Republic of China.
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Landry T, Shookster D, Huang H. Circulating α-klotho regulates metabolism via distinct central and peripheral mechanisms. Metabolism 2021; 121:154819. [PMID: 34153302 PMCID: PMC8277751 DOI: 10.1016/j.metabol.2021.154819] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/08/2021] [Accepted: 06/16/2021] [Indexed: 12/24/2022]
Abstract
Emerging evidence implicates the circulating α-klotho protein as a prominent regulator of energy balance and substrate metabolism, with diverse, tissue-specific functions. Despite its well-documented ubiquitous role inhibiting insulin signaling, α-klotho elicits potent antidiabetic and anti-obesogenic effects. α-Klotho facilitates insulin release and promotes β cell health in the pancreas, stimulates lipid oxidation in liver and adipose tissue, attenuates hepatic gluconeogenesis, and increases whole-body energy expenditure. The mechanisms underlying α-klotho's peripheral functions are multifaceted, including hydrolyzing transient receptor potential channels, stimulating integrin β1➔focal adhesion kinase signaling, and activating PPARα via inhibition of insulin-like growth factor receptor 1. Moreover, until recently, potential metabolic roles of α-klotho in the central nervous system remained unexplored; however, a novel α-klotho➔fibroblast growth factor receptor➔PI3kinase signaling axis in the arcuate nucleus of the hypothalamus has been identified as a critical regulator of energy balance and glucose metabolism. Overall, the role of circulating α-klotho in the regulation of metabolism is a new focus of research, but accumulating evidence identifies this protein as an encouraging therapeutic target for Type 1 and 2 Diabetes and obesity. This review analyzes the new literature investigating α-klotho-mediated regulation of metabolism and proposes impactful future directions to progress our understanding of this complex metabolic protein.
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Affiliation(s)
- Taylor Landry
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA; Department of Kinesiology, East Carolina University, Greenville, NC, USA; Human Performance Laboratory, College of Human Performance and Health, East Carolina University, Greenville, NC, USA
| | - Daniel Shookster
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA; Department of Kinesiology, East Carolina University, Greenville, NC, USA; Human Performance Laboratory, College of Human Performance and Health, East Carolina University, Greenville, NC, USA
| | - Hu Huang
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, NC, USA; Department of Kinesiology, East Carolina University, Greenville, NC, USA; Human Performance Laboratory, College of Human Performance and Health, East Carolina University, Greenville, NC, USA; Department of Physiology, East Carolina University, Greenville, NC, USA.
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Role of Thioredoxin-Interacting Protein in Diseases and Its Therapeutic Outlook. Int J Mol Sci 2021; 22:ijms22052754. [PMID: 33803178 PMCID: PMC7963165 DOI: 10.3390/ijms22052754] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/03/2021] [Indexed: 12/11/2022] Open
Abstract
Thioredoxin-interacting protein (TXNIP), widely known as thioredoxin-binding protein 2 (TBP2), is a major binding mediator in the thioredoxin (TXN) antioxidant system, which involves a reduction-oxidation (redox) signaling complex and is pivotal for the pathophysiology of some diseases. TXNIP increases reactive oxygen species production and oxidative stress and thereby contributes to apoptosis. Recent studies indicate an evolving role of TXNIP in the pathogenesis of complex diseases such as metabolic disorders, neurological disorders, and inflammatory illnesses. In addition, TXNIP has gained significant attention due to its wide range of functions in energy metabolism, insulin sensitivity, improved insulin secretion, and also in the regulation of glucose and tumor suppressor activities in various cancers. This review aims to highlight the roles of TXNIP in the field of diabetology, neurodegenerative diseases, and inflammation. TXNIP is found to be a promising novel therapeutic target in the current review, not only in the aforementioned diseases but also in prolonged microvascular and macrovascular diseases. Therefore, TXNIP inhibitors hold promise for preventing the growing incidence of complications in relevant diseases.
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12
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Zhong L, Liu Q, Liu Q, Zhang S, Cao Y, Yang D, Wang MW. W2476 represses TXNIP transcription via dephosphorylation of FOXO1 at Ser319. Chem Biol Drug Des 2021; 97:1089-1099. [PMID: 33560565 DOI: 10.1111/cbdd.13828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/27/2021] [Accepted: 01/31/2021] [Indexed: 12/20/2022]
Abstract
Thioredoxin-interacting protein (TXNIP) overexpression is implicated in the pathogenesis of type 2 diabetes. Previous studies have shown that a small molecule compound (W2476) was able to improve β-cell dysfunction and exert therapeutic effects in diabetic mice via repression of TXNIP signaling pathway. The impact of W2476 on TXNIP transcription was thus investigated using the chromatin immunoprecipitation method. It was found that W2476 promotes competitive binding of forkhead box O1 transcription factor (FOXO1) to the carbohydrate response element (ChoRE) sequence associated with ChoRE-binding protein (ChREBP)/Mlx interacting protein-like(Mlx) complexes. This interaction hinders the attachment of histone acetyltransferase p300 and reduces histone H4 acetylation on the TXNIP promoter, leading to decreasing TXNIP transcription.
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Affiliation(s)
- Li Zhong
- The National Center for Drug Screening, CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qing Liu
- The National Center for Drug Screening, CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, China
| | - Qiaofeng Liu
- School of Pharmacy, Fudan University, Shanghai, China
| | - Shikai Zhang
- Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yongbing Cao
- Shanghai TCM-Integrated Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Dehua Yang
- The National Center for Drug Screening, CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, China
| | - Ming-Wei Wang
- The National Center for Drug Screening, CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,School of Pharmacy, Fudan University, Shanghai, China
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13
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Zhao W, Pu M, Shen S, Yin F. Geniposide improves insulin resistance through AMPK-mediated Txnip protein degradation in 3T3-L1 adipocytes. Acta Biochim Biophys Sin (Shanghai) 2021; 53:160-169. [PMID: 33349852 DOI: 10.1093/abbs/gmaa157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Indexed: 12/29/2022] Open
Abstract
Thioredoxin-interacting protein (Txnip) has emerged as a key regulator of insulin resistance. In this study, we investigated the roles of geniposide and Txnip in insulin resistance in differentiated 3T3-L1 adipocytes. Our results revealed that geniposide markedly enhanced glucose uptake, increased the protein levels of insulin receptor substrate (IRS)-1 and GLUT-1, and prevented the phosphorylation of IRS-1 and Akt Thr308 induced by insulin resistance in 3T3-L1 adipocytes. We also observed that geniposide accelerated protein degradation of Txnip through proteasome pathway, and knockdown of Txnip with small interfering RNA attenuated the effect of geniposide on insulin signaling molecules, implying that Txnip played a pivotal role in the regulation of insulin signaling molecules by geniposide in 3T3-L1 adipocytes. Furthermore, geniposide induced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) in the presence of high glucose in differentiated 3T3-L1 adipocytes, while compound C, an inhibitor of AMPK, prevented the effect of geniposide on Txnip degradation and the regulation of glucose uptake and insulin signaling molecules including p-IRS-1, IRS-1, and GLUT-1 in differentiated 3T3-L1 adipocytes. Taken together, all these findings suggest that geniposide improves the insulin signaling defect possibly by AMPK-mediated Txnip degradation in 3T3-L1 adipocytes.
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Affiliation(s)
- Wanjun Zhao
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
| | - Mengru Pu
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
| | - Shenli Shen
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
| | - Fei Yin
- Chongqing Key Lab of Medicinal Chemistry & Molecular Pharmacology of Technology, Chongqing University of Technology, Chongqing 400054, China
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14
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Shi Z, Qin M, Huang L, Xu T, Chen Y, Hu Q, Peng S, Peng Z, Qu LN, Chen SG, Tuo QH, Liao DF, Wang XP, Wu RR, Yuan TF, Li YH, Liu XM. Human torpor: translating insights from nature into manned deep space expedition. Biol Rev Camb Philos Soc 2020; 96:642-672. [PMID: 33314677 DOI: 10.1111/brv.12671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (Tb ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.
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Affiliation(s)
- Zhe Shi
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.,Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Meng Qin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Tao Xu
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Qin Hu
- College of Life Sciences and Bio-Engineering, Beijing University of Technology, Beijing, 100024, China
| | - Sha Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Zhuang Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Li-Na Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shan-Guang Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Qin-Hui Tuo
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Duan-Fang Liao
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Xiao-Ping Wang
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ren-Rong Wu
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, China
| | - Ying-Hui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xin-Min Liu
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193, China
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15
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Thioredoxin-Interacting Protein (TXNIP) with Focus on Brain and Neurodegenerative Diseases. Int J Mol Sci 2020; 21:ijms21249357. [PMID: 33302545 PMCID: PMC7764580 DOI: 10.3390/ijms21249357] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 12/11/2022] Open
Abstract
The development of new therapeutic approaches to diseases relies on the identification of key molecular targets involved in amplifying disease processes. One such molecule is thioredoxin-interacting protein (TXNIP), also designated thioredoxin-binding protein-2 (TBP-2), a member of the α-arrestin family of proteins and a central regulator of glucose and lipid metabolism, involved in diabetes-associated vascular endothelial dysfunction and inflammation. TXNIP sequesters reduced thioredoxin (TRX), inhibiting its function, resulting in increased oxidative stress. Many different cellular stress factors regulate TXNIP expression, including high glucose, endoplasmic reticulum stress, free radicals, hypoxia, nitric oxide, insulin, and adenosine-containing molecules. TXNIP is also directly involved in inflammatory activation through its interaction with the nucleotide-binding domain, leucine-rich-containing family, and pyrin domain-containing-3 (NLRP3) inflammasome complex. Neurodegenerative diseases such as Alzheimer’s disease have significant pathologies associated with increased oxidative stress, inflammation, and vascular dysfunctions. In addition, as dysfunctions in glucose and cellular metabolism have been associated with such brain diseases, a role for TXNIP in neurodegeneration has actively been investigated. In this review, we will focus on the current state of the understanding of possible normal and pathological functions of TXNIP in the central nervous system from studies of in vitro neural cells and the brains of humans and experimental animals with reference to other studies. As TXNIP can be expressed by neurons, microglia, astrocytes, and endothelial cells, a complex pattern of regulation and function in the brain is suggested. We will examine data suggesting TXNIP as a therapeutic target for neurodegenerative diseases where further research is needed.
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16
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Yoshihara E. TXNIP/TBP-2: A Master Regulator for Glucose Homeostasis. Antioxidants (Basel) 2020; 9:E765. [PMID: 32824669 PMCID: PMC7464905 DOI: 10.3390/antiox9080765] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023] Open
Abstract
Identification of thioredoxin binding protein-2 (TBP-2), which is currently known as thioredoxin interacting protein (TXNIP), as an important binding partner for thioredoxin (TRX) revealed that an evolutionarily conserved reduction-oxidation (redox) signal complex plays an important role for pathophysiology. Due to the reducing activity of TRX, the TRX/TXNIP signal complex has been shown to be an important regulator for redox-related signal transduction in many types of cells in various species. In addition to its role in redox-dependent regulation, TXNIP has cellular functions that are performed in a redox-independent manner, which largely rely on their scaffolding function as an ancestral α-Arrestin family. Both the redox-dependent and -independent TXNIP functions serve as regulatory pathways in glucose metabolism. This review highlights the key advances in understanding TXNIP function as a master regulator for whole-body glucose homeostasis. The potential for therapeutic advantages of targeting TXNIP in diabetes and the future direction of the study are also discussed.
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Affiliation(s)
- Eiji Yoshihara
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA;
- David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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17
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Whipple AJ, Breton-Provencher V, Jacobs HN, Chitta UK, Sur M, Sharp PA. Imprinted Maternally Expressed microRNAs Antagonize Paternally Driven Gene Programs in Neurons. Mol Cell 2020; 78:85-95.e8. [PMID: 32032531 PMCID: PMC7176019 DOI: 10.1016/j.molcel.2020.01.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/03/2019] [Accepted: 01/15/2020] [Indexed: 12/24/2022]
Abstract
Imprinted genes with parental-biased allelic expression are frequently co-regulated and enriched in common biological pathways. Here, we functionally characterize a large cluster of microRNAs (miRNAs) expressed from the maternally inherited allele ("maternally expressed") to explore the molecular and cellular consequences of imprinted miRNA activity. Using an induced neuron (iN) culture system, we show that maternally expressed miRNAs from the miR-379/410 cluster direct the RNA-induced silencing complex (RISC) to transcriptional and developmental regulators, including paternally expressed transcripts like Plagl1. Maternal deletion of this imprinted miRNA cluster resulted in increased protein levels of several targets and upregulation of a broader transcriptional program regulating synaptic transmission and neuronal function. A subset of the transcriptional changes resulting from miR-379/410 deletion can be attributed to de-repression of Plagl1. These data suggest maternally expressed miRNAs antagonize paternally driven gene programs in neurons.
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Affiliation(s)
- Amanda J Whipple
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
| | - Vincent Breton-Provencher
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hannah N Jacobs
- Biological Sciences Department, Wellesley College, Wellesley, MA 02481, USA
| | - Udbhav K Chitta
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Mriganka Sur
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Phillip A Sharp
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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18
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Estrogen protects neuroblastoma cell from amyloid-β 42 (Aβ42)-induced apoptosis via TXNIP/TRX axis and AMPK signaling. Neurochem Int 2020; 135:104685. [PMID: 31931042 DOI: 10.1016/j.neuint.2020.104685] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 12/20/2019] [Accepted: 01/08/2020] [Indexed: 12/26/2022]
Abstract
Alzheimer's disease (AD), a massive challenge to global health, is featured with the extracellular plaques made up of amyloid-β 42 (Aβ42) and the intracellular neurofibrillary pathology composed of the microtubule-associated protein tau. Women seem to have a higher vulnerability to AD. In the present study, we identified Thioredoxin-interacting protein (TXNIP) as a specifically highly-expressed gene in the hippocampus in female AD patients by bioinformatics analysis. Consistently, in the hippocampus in female AD mice, apoptosis and TXNIP expression were enhanced while TRX expression was suppressed. In Aβ42-stimulated SH-SY5Y cells, the administration of estradiol significantly rescued Aβ42-suppressed cell viability and protein level of TRX while inhibited Aβ42-induced increases in ROS production, cell apoptosis, ΔΨm, and the protein levels of PERK, IREα, and TXNIP, further confirming the potential role of estrogen in AD progression and the involvement of TXNIP/TRX axis. Furthermore, the protective effects of estradiol against Aβ42-induced in vitro neurotoxicity on SH-SY5Y cells could be significantly reversed by AMPK inhibitor, Compound C, indicating that estradiol could improve Aβ42-induced AD via TXNIP/TRX and AMPK signaling. In summary, we demonstrated the cellular function of estradiol on Aβ42-induced in vitro neurotoxicity on SH-SY5Y cells and a novel mechanism of TXNIP/TRX axis involved in estradiol function via AMPK signaling.
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19
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Nasoohi S, Parveen K, Ishrat T. Metabolic Syndrome, Brain Insulin Resistance, and Alzheimer's Disease: Thioredoxin Interacting Protein (TXNIP) and Inflammasome as Core Amplifiers. J Alzheimers Dis 2019; 66:857-885. [PMID: 30372683 DOI: 10.3233/jad-180735] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Empirical evidence indicates a strong association between insulin resistance and pathological alterations related to Alzheimer's disease (AD) in different cerebral regions. While cerebral insulin resistance is not essentially parallel with systemic metabolic derangements, type 2 diabetes mellitus (T2DM) has been established as a risk factor for AD. The circulating "toxic metabolites" emerging in metabolic syndrome may engage several biochemical pathways to promote oxidative stress and neuroinflammation leading to impair insulin function in the brain or "type 3 diabetes". Thioredoxin-interacting protein (TXNIP) as an intracellular amplifier of oxidative stress and inflammasome activation may presumably mediate central insulin resistance. Emerging data including those from our recent studies has demonstrated a sharp TXNIP upregulation in stroke, aging and AD and well underlining the significance of this hypothesis. With the main interest to illustrate TXNIP place in type 3 diabetes, the present review primarily briefs the potential mechanisms contributing to cerebral insulin resistance in a metabolically deranged environment. Then with a particular focus on plausible TXNIP functions to drive and associate with AD pathology, we present the most recent evidence supporting TXNIP as a promising therapeutic target in AD as an age-associated dementia.
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20
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Multidimensional informatic deconvolution defines gender-specific roles of hypothalamic GIT2 in aging trajectories. Mech Ageing Dev 2019; 184:111150. [PMID: 31574270 DOI: 10.1016/j.mad.2019.111150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/20/2019] [Accepted: 09/26/2019] [Indexed: 12/13/2022]
Abstract
In most species, females live longer than males. An understanding of this female longevity advantage will likely uncover novel anti-aging therapeutic targets. Here we investigated the transcriptomic responses in the hypothalamus - a key organ for somatic aging control - to the introduction of a simple aging-related molecular perturbation, i.e. GIT2 heterozygosity. Our previous work has demonstrated that GIT2 acts as a network controller of aging. A similar number of both total (1079-female, 1006-male) and gender-unique (577-female, 527-male) transcripts were significantly altered in response to GIT2 heterozygosity in early life-stage (2 month-old) mice. Despite a similar volume of transcriptomic disruption in females and males, a considerably stronger dataset coherency and functional annotation representation was observed for females. It was also evident that female mice possessed a greater resilience to pro-aging signaling pathways compared to males. Using a highly data-dependent natural language processing informatics pipeline, we identified novel functional data clusters that were connected by a coherent group of multifunctional transcripts. From these it was clear that females prioritized metabolic activity preservation compared to males to mitigate this pro-aging perturbation. These findings were corroborated by somatic metabolism analyses of living animals, demonstrating the efficacy of our new informatics pipeline.
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21
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Genome-Wide Profiling of Laron Syndrome Patients Identifies Novel Cancer Protection Pathways. Cells 2019; 8:cells8060596. [PMID: 31208077 PMCID: PMC6627189 DOI: 10.3390/cells8060596] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 12/30/2022] Open
Abstract
Laron syndrome (LS), or primary growth hormone resistance, is a prototypical congenital insulin-like growth factor 1 (IGF1) deficiency. The recent epidemiological finding that LS patients do not develop cancer is of major scientific and clinical relevance. Epidemiological data suggest that congenital IGF1 deficiency confers protection against the development of malignancies. This ‘experiment of nature’ reflects the critical role of IGF1 in tumor biology. The present review article provides an overview of recently conducted genome-wide profiling analyses aimed at identifying mechanisms and signaling pathways that are directly responsible for the link between life-time low IGF1 levels and protection from tumor development. The review underscores the concept that ‘data mining’ an orphan disease might translate into new developments in oncology.
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Abstract
The hypothalamus is the central neural site governing food intake and energy expenditure. During the past 25 years, understanding of the hypothalamic cell types, hormones, and circuitry involved in the regulation of energy metabolism has dramatically increased. It is now well established that the adipocyte-derived hormone, leptin, acts upon two distinct groups of hypothalamic neurons that comprise opposing arms of the central melanocortin system. These two cell populations are anorexigenic neurons expressing proopiomelanocortin (POMC) and orexigenic neurons that express agouti-related peptide (AGRP). Several important studies have demonstrated that reactive oxygen species and endoplasmic reticulum stress significantly impact these hypothalamic neuronal populations that regulate global energy metabolism. Reactive oxygen species and redox homeostasis are influenced by selenoproteins, an essential class of proteins that incorporate selenium co-translationally in the form of the 21st amino acid, selenocysteine. Levels of these proteins are regulated by dietary selenium intake and they are widely expressed in the brain. Of additional relevance, selenium supplementation has been linked to metabolic alterations in both animal and human studies. Recent evidence also indicates that hypothalamic selenoproteins are significant modulators of energy metabolism in both neurons and tanycytes, a population of glial-like cells lining the floor of the 3rd ventricle within the hypothalamus. This review article will summarize current understanding of the regulatory influence of redox status on hypothalamic nutrient sensing and highlight recent work revealing the importance of selenoproteins in the hypothalamus.
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Affiliation(s)
- Ting Gong
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, HI 96813, USA
| | - Daniel J Torres
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
| | - Marla J Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA
| | - Matthew W Pitts
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, HI 96813, USA.
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Alhawiti NM, Al Mahri S, Aziz MA, Malik SS, Mohammad S. TXNIP in Metabolic Regulation: Physiological Role and Therapeutic Outlook. Curr Drug Targets 2018; 18:1095-1103. [PMID: 28137209 PMCID: PMC5543564 DOI: 10.2174/1389450118666170130145514] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/04/2017] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
Abstract
Background & Objective: Thioredoxin-interacting protein (TXNIP) also known as thioredoxin binding protein-2 is a ubiquitously expressed protein that interacts and negatively regulates expression and function of Thioredoxin (TXN). Over the last few years, TXNIP has attracted considerable attention due to its wide-ranging functions impacting several aspects of energy metabolism. TXNIP acts as an important regulator of glucose and lipid metabolism through pleiotropic actions including regulation of β-cell function, hepatic glucose production, peripheral glucose uptake, adipogenesis, and substrate utilization. Overexpression of TXNIP in animal models has been shown to induce apoptosis of pancreatic β-cells, reduce insulin sensitivity in peripheral tissues like skeletal muscle and adipose, and decrease energy expenditure. On the contrary, TXNIP deficient animals are protected from diet induced insulin resistance and type 2 diabetes. Summary: Consequently, targeting TXNIP is thought to offer novel therapeutic opportunity and TXNIP inhibitors have the potential to become a powerful therapeutic tool for the treatment of diabetes mellitus. Here we summarize the current state of our understanding of TXNIP biology, highlight its role in metabolic regulation and raise critical questions that could help future research to exploit TXNIP as a therapeutic target.
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Affiliation(s)
- Naif Mohammad Alhawiti
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Saeed Al Mahri
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Mohammad Azhar Aziz
- Colorectal Cancer Research Program, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Shuja Shafi Malik
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
| | - Sameer Mohammad
- Experimental Medicine, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences (KSAU-HS), Ministry of National Guard Health Affairs (NGHA), Riyadh, Saudi Arabia
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Thielen L, Shalev A. Diabetes pathogenic mechanisms and potential new therapies based upon a novel target called TXNIP. Curr Opin Endocrinol Diabetes Obes 2018; 25:75-80. [PMID: 29356688 PMCID: PMC5831522 DOI: 10.1097/med.0000000000000391] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW Thioredoxin-interacting protein has emerged as a major factor regulating pancreatic β-cell dysfunction and death, key processes in the pathogenesis of type 1 and type 2 diabetes. Accumulating evidence based on basic, preclinical, and retrospective epidemiological research suggests that TXNIP represents a promising therapeutic target for diabetes. The present review is aimed at providing an update regarding these developments. RECENT FINDINGS TXNIP has been shown to be induced by glucose and increased in diabetes and to promote β-cell apoptosis, whereas TXNIP deletion protected against diabetes. More recently, TXNIP inhibition has also been found to promote insulin production and glucagon-like peptide 1 signaling via regulation of a microRNA. β-Cell TXNIP expression itself was found to be regulated by hypoglycemic agents, carbohydrate-response-element-binding protein, and cytosolic calcium or the calcium channel blocker, verapamil. Retrospective studies now further suggest that verapamil use might be associated with a lower incidence of type 2 diabetes in humans. SUMMARY TXNIP has emerged as a key factor in the regulation of functional β-cell mass and TXNIP inhibition has shown beneficial effects in a variety of studies. Thus, the inhibition of TXNIP may provide a novel approach to the treatment of diabetes.
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Affiliation(s)
- Lance Thielen
- Division of Endocrinology, Diabetes, and Metabolism, Comprehensive Diabetes Center and Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
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25
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Zhou C, Teegala SB, Khan BA, Gonzalez C, Routh VH. Hypoglycemia: Role of Hypothalamic Glucose-Inhibited (GI) Neurons in Detection and Correction. Front Physiol 2018; 9:192. [PMID: 29593556 PMCID: PMC5854653 DOI: 10.3389/fphys.2018.00192] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/23/2018] [Indexed: 01/08/2023] Open
Abstract
Hypoglycemia is a profound threat to the brain since glucose is its primary fuel. As a result, glucose sensors are widely located in the central nervous system and periphery. In this perspective we will focus on the role of hypothalamic glucose-inhibited (GI) neurons in sensing and correcting hypoglycemia. In particular, we will discuss GI neurons in the ventromedial hypothalamus (VMH) which express neuronal nitric oxide synthase (nNOS) and in the perifornical hypothalamus (PFH) which express orexin. The ability of VMH nNOS-GI neurons to depolarize in low glucose closely parallels the hormonal response to hypoglycemia which stimulates gluconeogenesis. We have found that nitric oxide (NO) production in low glucose is dependent on oxidative status. In this perspective we will discuss the potential relevance of our work showing that enhancing the glutathione antioxidant system prevents hypoglycemia associated autonomic failure (HAAF) in non-diabetic rats whereas VMH overexpression of the thioredoxin antioxidant system restores hypoglycemia counterregulation in rats with type 1 diabetes.We will also address the potential role of the orexin-GI neurons in the arousal response needed for hypoglycemia awareness which leads to behavioral correction (e.g., food intake, glucose administration). The potential relationship between the hypothalamic sensors and the neurocircuitry in the hindbrain and portal mesenteric vein which is critical for hypoglycemia correction will then be discussed.
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Affiliation(s)
| | | | | | | | - Vanessa H. Routh
- Department of Pharmacology, Physiology and Neurosciences, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
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Identification of thioredoxin-interacting protein (TXNIP) as a downstream target for IGF1 action. Proc Natl Acad Sci U S A 2018; 115:1045-1050. [PMID: 29339473 DOI: 10.1073/pnas.1715930115] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Laron syndrome (LS), or primary growth hormone (GH) insensitivity, is the best-characterized entity among the congenital insulin-like growth factor 1 (IGF1) deficiencies. Life-long exposure to minute endogenous IGF1 levels is linked to low stature as well as a number of endocrine and metabolic abnormalities. While elevated IGF1 is correlated with increased cancer incidence, epidemiological studies revealed that patients with LS do not develop tumors. The mechanisms associated with cancer protection in LS are yet to be discovered. Recent genomic analyses identified a series of metabolic genes that are overrepresented in patients with LS. Given the augmented expression of these genes in a low IGF1 milieu, we hypothesized that they may constitute targets for IGF1 action. Thioredoxin-interacting protein (TXNIP) plays a critical role in cellular redox control by thioredoxin. TXNIP serves as a glucose and oxidative stress sensor, being commonly silenced by genetic or epigenetic events in cancer cells. Consistent with its enhanced expression in LS, we provide evidence that TXNIP gene expression is negatively regulated by IGF1. These results were corroborated in animal studies. In addition, we show that oxidative and glucose stresses led to marked increases in TXNIP expression. Supplementation of IGF1 attenuated TXNIP levels, suggesting that IGF1 exerts its antiapoptotic effect via inhibition of TXNIP Augmented TXNIP expression in LS may account for cancer protection in this condition. Finally, TXNIP levels could be potentially useful in the clinic as a predictive or diagnostic biomarker for IGF1R-targeted therapies.
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Jastroch M, Giroud S, Barrett P, Geiser F, Heldmaier G, Herwig A. Seasonal Control of Mammalian Energy Balance: Recent Advances in the Understanding of Daily Torpor and Hibernation. J Neuroendocrinol 2016; 28. [PMID: 27755687 DOI: 10.1111/jne.12437] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 10/07/2016] [Accepted: 10/15/2016] [Indexed: 12/20/2022]
Abstract
Endothermic mammals and birds require intensive energy turnover to sustain high body temperatures and metabolic rates. To cope with the energetic bottlenecks associated with the change of seasons, and to minimise energy expenditure, complex mechanisms and strategies are used, such as daily torpor and hibernation. During torpor, metabolic depression and low body temperatures save energy. However, these bouts of torpor, lasting for hours to weeks, are interrupted by active 'euthermic' phases with high body temperatures. These dynamic transitions require precise communication between the brain and peripheral tissues to defend rheostasis in energetics, body mass and body temperature. The hypothalamus appears to be the major control centre in the brain, coordinating energy metabolism and body temperature. The sympathetic nervous system controls body temperature by adjustments of shivering and nonshivering thermogenesis, with the latter being primarily executed by brown adipose tissue. Over the last decade, comparative physiologists have put forward integrative studies on the ecophysiology, biochemistry and molecular regulation of energy balance in response to seasonal challenges, food availability and ambient temperature. Mammals coping with such environments comprise excellent model organisms for studying the dynamic regulation of energy metabolism. Beyond the understanding of how animals survive in nature, these studies also uncover general mechanisms of mammalian energy homeostasis. This research will benefit efforts of translational medicine aiming to combat emerging human metabolic disorders. The present review focuses on recent advances in the understanding of energy balance and its neuronal and endocrine control during the most extreme metabolic fluctuations in nature: daily torpor and hibernation.
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Affiliation(s)
- M Jastroch
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center & German Diabetes Center (DZD), Helmholtz Zentrum München, Neuherberg, Germany
| | - S Giroud
- Department of Integrative Biology and Evolution, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - P Barrett
- Rowett Institute for Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - F Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
| | - G Heldmaier
- Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - A Herwig
- Zoological Institute, University of Hamburg, Hamburg, Germany
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Imbalanced insulin action in chronic over nutrition: Clinical harm, molecular mechanisms, and a way forward. Atherosclerosis 2016; 247:225-82. [PMID: 26967715 DOI: 10.1016/j.atherosclerosis.2016.02.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/31/2015] [Accepted: 02/02/2016] [Indexed: 02/08/2023]
Abstract
The growing worldwide prevalence of overnutrition and underexertion threatens the gains that we have made against atherosclerotic cardiovascular disease and other maladies. Chronic overnutrition causes the atherometabolic syndrome, which is a cluster of seemingly unrelated health problems characterized by increased abdominal girth and body-mass index, high fasting and postprandial concentrations of cholesterol- and triglyceride-rich apoB-lipoproteins (C-TRLs), low plasma HDL levels, impaired regulation of plasma glucose concentrations, hypertension, and a significant risk of developing overt type 2 diabetes mellitus (T2DM). In addition, individuals with this syndrome exhibit fatty liver, hypercoagulability, sympathetic overactivity, a gradually rising set-point for body adiposity, a substantially increased risk of atherosclerotic cardiovascular morbidity and mortality, and--crucially--hyperinsulinemia. Many lines of evidence indicate that each component of the atherometabolic syndrome arises, or is worsened by, pathway-selective insulin resistance and responsiveness (SEIRR). Individuals with SEIRR require compensatory hyperinsulinemia to control plasma glucose levels. The result is overdrive of those pathways that remain insulin-responsive, particularly ERK activation and hepatic de-novo lipogenesis (DNL), while carbohydrate regulation deteriorates. The effects are easily summarized: if hyperinsulinemia does something bad in a tissue or organ, that effect remains responsive in the atherometabolic syndrome and T2DM; and if hyperinsulinemia might do something good, that effect becomes resistant. It is a deadly imbalance in insulin action. From the standpoint of human health, it is the worst possible combination of effects. In this review, we discuss the origins of the atherometabolic syndrome in our historically unprecedented environment that only recently has become full of poorly satiating calories and incessant enticements to sit. Data are examined that indicate the magnitude of daily caloric imbalance that causes obesity. We also cover key aspects of healthy, balanced insulin action in liver, endothelium, brain, and elsewhere. Recent insights into the molecular basis and pathophysiologic harm from SEIRR in these organs are discussed. Importantly, a newly discovered oxide transport chain functions as the master regulator of the balance amongst different limbs of the insulin signaling cascade. This oxide transport chain--abbreviated 'NSAPP' after its five major proteins--fails to function properly during chronic overnutrition, resulting in this harmful pattern of SEIRR. We also review the origins of widespread, chronic overnutrition. Despite its apparent complexity, one factor stands out. A sophisticated junk food industry, aided by subsidies from willing governments, has devoted years of careful effort to promote overeating through the creation of a new class of food and drink that is low- or no-cost to the consumer, convenient, savory, calorically dense, yet weakly satiating. It is past time for the rest of us to overcome these foes of good health and solve this man-made epidemic.
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Sasaki T, Kikuchi O, Shimpuku M, Susanti VY, Yokota-Hashimoto H, Taguchi R, Shibusawa N, Sato T, Tang L, Amano K, Kitazumi T, Kuroko M, Fujita Y, Maruyama J, Lee YS, Kobayashi M, Nakagawa T, Minokoshi Y, Harada A, Yamada M, Kitamura T. Hypothalamic SIRT1 prevents age-associated weight gain by improving leptin sensitivity in mice. Diabetologia 2014; 57:819-31. [PMID: 24374551 PMCID: PMC3940852 DOI: 10.1007/s00125-013-3140-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 11/25/2013] [Indexed: 01/10/2023]
Abstract
AIMS/HYPOTHESIS Obesity is associated with ageing and increased energy intake, while restriction of energy intake improves health and longevity in multiple organisms; the NAD(+)-dependent deacetylase sirtuin 1 (SIRT1) is implicated in this process. Pro-opiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons in the arcuate nucleus (ARC) of the hypothalamus are critical for energy balance regulation, and the level of SIRT1 protein decreases with age in the ARC. In the current study we tested whether conditional Sirt1 overexpression in mouse POMC or AgRP neurons prevents age-associated weight gain and diet-induced obesity. METHODS We targeted Sirt1 cDNA sequence into the Rosa26 locus and generated conditional Sirt1 knock-in mice. These mice were crossed with mice harbouring either Pomc-Cre or Agrp-Cre and the metabolic variables, food intake, energy expenditure and sympathetic activity in adipose tissue of the resultant mice were analysed. We also used a hypothalamic cell line to investigate the molecular mechanism by which Sirt1 overexpression modulates leptin signalling. RESULTS Conditional Sirt1 overexpression in mouse POMC or AgRP neurons prevented age-associated weight gain; overexpression in POMC neurons stimulated energy expenditure via increased sympathetic activity in adipose tissue, whereas overexpression in AgRP neurons suppressed food intake. SIRT1 improved leptin sensitivity in hypothalamic neurons in vitro and in vivo by downregulating protein-tyrosine phosphatase 1B, T cell protein-tyrosine phosphatase and suppressor of cytokine signalling 3. However, these phenotypes were absent in mice consuming a high-fat, high-sucrose diet due to decreases in ARC SIRT1 protein and hypothalamic NAD(+) levels. CONCLUSIONS/INTERPRETATION ARC SIRT1 is a negative regulator of energy balance, and decline in ARC SIRT1 function contributes to disruption of energy homeostasis by ageing and diet-induced obesity.
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Affiliation(s)
- Tsutomu Sasaki
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Osamu Kikuchi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Mayumi Shimpuku
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Vina Yanti Susanti
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Hiromi Yokota-Hashimoto
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Ryo Taguchi
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma Japan
| | - Nobuyuki Shibusawa
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma Japan
| | - Takashi Sato
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma Japan
| | - Lijun Tang
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi Japan
| | - Kosuke Amano
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Tomoya Kitazumi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Mitsutaka Kuroko
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Yuki Fujita
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Jun Maruyama
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Yong-soo Lee
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Masaki Kobayashi
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
| | - Takashi Nakagawa
- Frontier Research Core for Life Science, University of Toyama, Toyama, Toyama Japan
| | - Yasuhiko Minokoshi
- Division of Endocrinology and Metabolism, Department of Developmental Physiology, National Institute for Physiological Sciences, Okazaki, Aichi Japan
| | - Akihiro Harada
- Laboratory of Molecular Traffic, Department of Molecular and Cellular Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma Japan
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Suita, Osaka Japan
| | - Masanobu Yamada
- Department of Medicine and Molecular Science, Graduate School of Medicine, Gunma University, Maebashi, Gunma Japan
| | - Tadahiro Kitamura
- Metabolic Signal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi-shi, Gunma 371-8512 Japan
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Zhang QY, Pan Y, Wang R, Kang LL, Xue QC, Wang XN, Kong LD. Quercetin inhibits AMPK/TXNIP activation and reduces inflammatory lesions to improve insulin signaling defect in the hypothalamus of high fructose-fed rats. J Nutr Biochem 2013; 25:420-8. [PMID: 24491314 DOI: 10.1016/j.jnutbio.2013.11.014] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 11/17/2013] [Accepted: 11/27/2013] [Indexed: 12/18/2022]
Abstract
Fructose is a nutritional composition of fruits and honey. Its excess consumption induces insulin resistance-associated metabolic diseases. Hypothalamic insulin signaling plays a pivotal role in controlling whole-body insulin sensitivity and energy homeostasis. Quercetin, a natural flavonoid, has been reported to ameliorate high fructose-induced rat insulin resistance and hyperlipidemia. In this study, we investigated its regulatory effects on the hypothalamus of high fructose-fed rats. Rats were fed 10% fructose in drinking water for 10 weeks. After 4 weeks, these animals were orally treated with quercetin (50 and 100 mg/kg), allopurinol (5 mg/kg) and water daily for the next 6 weeks, respectively. Quercetin effectively restored high fructose-induced hypothalamic insulin signaling defect by up-regulating the phosphorylation of insulin receptor and protein kinase B. Furthermore, quercetin was found to reduce metabolic nutrient sensors adenosine monophosphate-activated protein kinase (AMPK) activation and thioredoxin-interacting protein (TXNIP) overexpression, as well as the glutamine-glutamate cycle dysfunction in the hypothalamus of high fructose-fed rats. Subsequently, it ameliorated high fructose-caused hypothalamic inflammatory lesions in rats by suppressing the activation of hypothalamic nuclear factor κB (NF-κB) pathway and NOD-like receptor 3 (NLRP3) inflammasome with interleukin 1β maturation. Allopurinol had similar effects. These results provide in vivo evidence that quercetin-mediated down-regulation of AMPK/TXNIP and subsequent inhibition of NF-κB pathway/NLRP3 inflammasome activation in the hypothalamus of rats may be associated with the reduction of hypothalamic inflammatory lesions, contributing to the improvement of hypothalamic insulin signaling defect in this model. Thus, quercetin with the central activity may be a therapeutic for high fructose-induced insulin resistance and hyperlipidemia in humans.
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Affiliation(s)
- Qing-Yu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China
| | - Ying Pan
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China.
| | - Rong Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China
| | - Lin-Lin Kang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China
| | - Qiao-Chu Xue
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China
| | - Xiao-Ning Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China
| | - Ling-Dong Kong
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093, PR China.
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Pitts MW, Reeves MA, Hashimoto AC, Ogawa A, Kremer P, Seale LA, Berry MJ. Deletion of selenoprotein M leads to obesity without cognitive deficits. J Biol Chem 2013; 288:26121-26134. [PMID: 23880772 DOI: 10.1074/jbc.m113.471235] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Selenium is an essential trace element that is co-translationally incorporated into selenoproteins in the form of the 21st amino acid, selenocysteine. This class of proteins largely functions in oxidation-reduction reactions and is critically involved in maintaining proper redox balance essential to health. Selenoprotein M (SelM) is a thioredoxin-like endoplasmic reticulum-resident protein that is highly expressed in the brain and possesses neuroprotective properties. In this study, we first assessed the regional pattern of SelM expression in the mouse brain to provide insights into the potential functional implications of this protein in physiology and behavior. Next, we generated transgenic mice with a targeted deletion of the SelM gene and subjected them to a battery of neurobehavioral tests to evaluate motor coordination, locomotion, and cognitive function in comparison with wild-type controls. Finally, these mice were tested for several measures of metabolic function and body composition. Our results show that SelM knock-out (KO) mice display no deficits in measures of motor coordination and cognitive function but exhibit increased weight gain, elevated white adipose tissue deposition, and diminished hypothalamic leptin sensitivity. These findings suggest that SelM plays an important role in the regulation of body weight and energy metabolism.
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Affiliation(s)
- Matthew W Pitts
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813.
| | - Mariclair A Reeves
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Ann C Hashimoto
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Ashley Ogawa
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Penny Kremer
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Lucia A Seale
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
| | - Marla J Berry
- From the Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96813
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Heo HS, Kim E, Jeon SM, Kwon EY, Shin SK, Paik H, Hur CG, Choi MS. A nutrigenomic framework to identify time-resolving responses of hepatic genes in diet-induced obese mice. Mol Cells 2013; 36:25-38. [PMID: 23813319 PMCID: PMC3887924 DOI: 10.1007/s10059-013-2336-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/08/2013] [Accepted: 04/10/2013] [Indexed: 10/26/2022] Open
Abstract
Obesity and its related complications have emerged as global health problems; however, the pathophysiological mechanism of obesity is still not fully understood. In this study, C57BL/6J mice were fed a normal (ND) or high-fat diet (HFD) for 0, 2, 4, 6, 8, 12, 20, and 24 weeks and the time course was systemically analyzed specifically for the hepatic transcriptome profile. Genes that were differentially expressed in the HFD-fed mice were clustered into 49 clusters and further classified into 8 different expression patterns: long-term up-regulated (pattern 1), long-term downregulated (pattern 2), early up-regulated (pattern 3), early down-regulated (pattern 4), late up-regulated (pattern 5), late down-regulated (pattern 6), early up-regulated and late down-regulated (pattern 7), and early down-regulated and late up-regulated (pattern 8) HFD-responsive genes. Within each pattern, genes related with inflammation, insulin resistance, and lipid metabolism were extracted, and then, a protein-protein interaction network was generated. The pattern specific sub-network was as follows: pattern 1, cellular assembly and organization, and immunological disease, pattern 2, lipid metabolism, pattern 3, gene expression and inflammatory response, pattern 4, cell signaling, pattern 5, lipid metabolism, molecular transport, and small molecule biochemistry, pattern 6, protein synthesis and cell-to cell signaling and interaction and pattern 7, cell-to cell signaling, cellular growth and proliferation, and cell death. For pattern 8, no significant sub-networks were identified. Taken together, this suggests that genes involved in regulating gene expression and inflammatory response are up-regulated whereas genes involved in lipid metabolism and protein synthesis are down-regulated during diet-induced obesity development.
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Affiliation(s)
- Hyoung-Sam Heo
- Green Bio Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
- Division of Bio-Medical Informatics, Center for Genome Science, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon 363-951,
Korea
| | - Eunjung Kim
- Department of Food Science and Nutrition, Catholic University of Daegu, Gyeongsan 712-702,
Korea
- Food and Nutritional Genomics Research Center, Kyungpook National University, Daegu 702-701,
Korea
| | - Seon-Min Jeon
- Food and Nutritional Genomics Research Center, Kyungpook National University, Daegu 702-701,
Korea
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 702-701,
Korea
| | - Eun-Young Kwon
- Food and Nutritional Genomics Research Center, Kyungpook National University, Daegu 702-701,
Korea
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 702-701,
Korea
| | - Su-Kyung Shin
- Food and Nutritional Genomics Research Center, Kyungpook National University, Daegu 702-701,
Korea
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 702-701,
Korea
| | - Hyojung Paik
- Green Bio Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
- Department of Biomedical Informatics, Ajou University School of Medicine, Suwon 443-749,
Korea
| | - Cheol-Goo Hur
- Green Bio Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806,
Korea
| | - Myung-Sook Choi
- Food and Nutritional Genomics Research Center, Kyungpook National University, Daegu 702-701,
Korea
- Department of Food Science and Nutrition, Kyungpook National University, Daegu 702-701,
Korea
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Ness D, Ren Z, Gardai S, Sharpnack D, Johnson VJ, Brennan RJ, Brigham EF, Olaharski AJ. Leucine-rich repeat kinase 2 (LRRK2)-deficient rats exhibit renal tubule injury and perturbations in metabolic and immunological homeostasis. PLoS One 2013; 8:e66164. [PMID: 23799078 PMCID: PMC3682960 DOI: 10.1371/journal.pone.0066164] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 05/02/2013] [Indexed: 11/18/2022] Open
Abstract
Genetic evidence links mutations in the LRRK2 gene with an increased risk of Parkinson's disease, for which no neuroprotective or neurorestorative therapies currently exist. While the role of LRRK2 in normal cellular function has yet to be fully described, evidence suggests involvement with immune and kidney functions. A comparative study of LRRK2-deficient and wild type rats investigated the influence that this gene has on the phenotype of these rats. Significant weight gain in the LRRK2 null rats was observed and was accompanied by significant increases in insulin and insulin-like growth factors. Additionally, LRRK2-deficient rats displayed kidney morphological and histopathological alterations in the renal tubule epithelial cells of all animals assessed. These perturbations in renal morphology were accompanied by significant decreases of lipocalin-2, in both the urine and plasma of knockout animals. Significant alterations in the cellular composition of the spleen between LRRK2 knockout and wild type animals were identified by immunophenotyping and were associated with subtle differences in response to dual infection with rat-adapted influenza virus (RAIV) and Streptococcus pneumoniae. Ontological pathway analysis of LRRK2 across metabolic and kidney processes and pathological categories suggested that the thioredoxin network may play a role in perturbing these organ systems. The phenotype of the LRRK2 null rat is suggestive of a complex biology influencing metabolism, immune function and kidney homeostasis. These data need to be extended to better understand the role of the kinase domain or other biological functions of the gene to better inform the development of pharmacological inhibitors.
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Affiliation(s)
- Daniel Ness
- Nonclinical Safety Evaluation, Elan Pharmaceuticals Inc., South San Francisco, California, United States of America
| | - Zhao Ren
- Assay Development, Elan Pharmaceuticals Inc., South San Francisco, California, United States of America
| | - Shyra Gardai
- Exploratory Biology, Elan Pharmaceuticals Inc., South San Francisco, California, United States of America
| | | | - Victor J. Johnson
- Burleson Research Technologies Inc. (BRT), Morrisville, North Carolina, United States of America
| | | | - Elizabeth F. Brigham
- Pharmacology, Elan Pharmaceuticals Inc., South San Francisco, California, United States of America
| | - Andrew J. Olaharski
- Nonclinical Safety Evaluation, Elan Pharmaceuticals Inc., South San Francisco, California, United States of America
- * E-mail:
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Hand LE, Saer BRC, Hui ST, Jinnah HA, Steinlechner S, Loudon ASI, Bechtold DA. Induction of the metabolic regulator Txnip in fasting-induced and natural torpor. Endocrinology 2013; 154:2081-91. [PMID: 23584857 PMCID: PMC3740491 DOI: 10.1210/en.2012-2051] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Torpor is a physiological state characterized by controlled lowering of metabolic rate and core body temperature, allowing substantial energy savings during periods of reduced food availability or harsh environmental conditions. The hypothalamus coordinates energy homeostasis and thermoregulation and plays a key role in directing torpor. We recently showed that mice lacking the orphan G protein-coupled receptor Gpr50 readily enter torpor in response to fasting and have now used these mice to conduct a microarray analysis of hypothalamic gene expression changes related to the torpor state. This revealed a strong induction of thioredoxin-interacting protein (Txnip) in the hypothalamus of torpid mice, which was confirmed by quantitative RT-PCR and Western blot analyses. In situ hybridization identified the ependyma lining the third ventricle as the principal site of torpor-related expression of Txnip. To characterize further the relationship between Txnip and torpor, we profiled Txnip expression in mice during prolonged fasting, cold exposure, and 2-deoxyglucose-induced hypometabolism, as well as in naturally occurring torpor bouts in the Siberian hamster. Strikingly, pronounced up-regulation of Txnip expression was only observed in wild-type mice when driven into torpor and during torpor in the Siberian hamster. Increase of Txnip was not limited to the hypothalamus, with exaggerated expression in white adipose tissue, brown adipose tissue, and liver also demonstrated in torpid mice. Given the recent identification of Txnip as a molecular nutrient sensor important in the regulation of energy metabolism, our data suggest that elevated Txnip expression is critical to regulating energy expenditure and fuel use during the extreme hypometabolic state of torpor.
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Affiliation(s)
- Laura E Hand
- Faculty of Life Sciences, AV Hill Building, University of Manchester, Manchester M13 9PT, UK
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35
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Affiliation(s)
- Francis J P Ebling
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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36
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Lee S, Kim SM, Lee RT. Thioredoxin and thioredoxin target proteins: from molecular mechanisms to functional significance. Antioxid Redox Signal 2013; 18:1165-207. [PMID: 22607099 PMCID: PMC3579385 DOI: 10.1089/ars.2011.4322] [Citation(s) in RCA: 282] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The thioredoxin (Trx) system is one of the central antioxidant systems in mammalian cells, maintaining a reducing environment by catalyzing electron flux from nicotinamide adenine dinucleotide phosphate through Trx reductase to Trx, which reduces its target proteins using highly conserved thiol groups. While the importance of protecting cells from the detrimental effects of reactive oxygen species is clear, decades of research in this field revealed that there is a network of redox-sensitive proteins forming redox-dependent signaling pathways that are crucial for fundamental cellular processes, including metabolism, proliferation, differentiation, migration, and apoptosis. Trx participates in signaling pathways interacting with different proteins to control their dynamic regulation of structure and function. In this review, we focus on Trx target proteins that are involved in redox-dependent signaling pathways. Specifically, Trx-dependent reductive enzymes that participate in classical redox reactions and redox-sensitive signaling molecules are discussed in greater detail. The latter are extensively discussed, as ongoing research unveils more and more details about the complex signaling networks of Trx-sensitive signaling molecules such as apoptosis signal-regulating kinase 1, Trx interacting protein, and phosphatase and tensin homolog, thus highlighting the potential direct and indirect impact of their redox-dependent interaction with Trx. Overall, the findings that are described here illustrate the importance and complexity of Trx-dependent, redox-sensitive signaling in the cell. Our increasing understanding of the components and mechanisms of these signaling pathways could lead to the identification of new potential targets for the treatment of diseases, including cancer and diabetes.
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Affiliation(s)
- Samuel Lee
- The Harvard Stem Cell Institute, Cambridge, MA, USA
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Abstract
Chronic hyperglycemia (HG)-associated reactive oxygen/nitrogen species (ROS/RNS) stress and low grade inflammation are considered to play critical roles in the development of diabetic retinopathy (DR). Excess glucose metabolic flux through the aldose reductase/polyol pathway, advanced glycation end product (AGE) formation, elevated hexosamine biosynthesis pathway (HBP), diacyl glycerol/PKC activation, and mitochondrial ROS generation are all implicated in DR. In addition, endoplasmic reticulum stress/unfolded protein response (er-UPR) and deregulation of mitochondrial quality control by autophagy/mitophagy are observed causing cellular bioenergetic deficiency and injury. Recently, a pro-oxidant and pro-apoptotic thioredoxin interacting protein (TXNIP) was shown to be highly upregulated in DR and by HG in retinal cells in culture. TXNIP binds to thioredoxin (Trx) inhibiting its oxidant scavenging and thiolreducing capacity. Hence, prolonged overexpression of TXNIP causes ROS/RNS stress, mitochondrial dysfunction, inflammation and premature cell death in DR. Initially, DR was considered as microvascular complications of endothelial dysfunction and pericyte loss characterized by capillary basement membrane thickening, pericyte ghost, blood retinal barrier leakage, acellular capillary and neovascularization. However, it is currently acknowledged that neuro-glia are also affected by HG in diabetes and that neuronal injury, glial activation, innate immunity/sterile inflammation, and ganglion apoptosis occur early in DR. In addition, retinal pigment epithelium (RPE) becomes dysfunctional in DR. Since TXNIP is induced by HG in most cells, its effects are not restricted to a particular cell type in DR. However, depending on the metabolic activity and anti-oxidant capacity, some cells may be affected earlier by TXNIP than others. Identification of TXNIP sensitive cells and elucidating the underlying mechanism(s) will be critical for preventing pre-mature cell death and progression of DR.
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Affiliation(s)
- Lalit P Singh
- Departments of Anatomy and Cell Biology and Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Berger JH, Charron MJ, Silver DL. Major facilitator superfamily domain-containing protein 2a (MFSD2A) has roles in body growth, motor function, and lipid metabolism. PLoS One 2012; 7:e50629. [PMID: 23209793 PMCID: PMC3510178 DOI: 10.1371/journal.pone.0050629] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 10/22/2012] [Indexed: 12/24/2022] Open
Abstract
The metabolic adaptations to fasting in the liver are largely controlled by the nuclear hormone receptor peroxisome proliferator-activated receptor alpha (PPARα), where PPARα upregulates genes encoding the biochemical pathway for β-oxidation of fatty acids and ketogenesis. As part of an effort to identify and characterize nutritionally regulated genes that play physiological roles in the adaptation to fasting, we identified Major facilitator superfamily domain-containing protein 2a (Mfsd2a) as a fasting-induced gene regulated by both PPARα and glucagon signaling in the liver. MFSD2A is a cell-surface protein homologous to bacterial sodium-melibiose transporters. Hepatic expression and turnover of MFSD2A is acutely regulated by fasting/refeeding, but expression in the brain is constitutive. Relative to wildtype mice, gene-targeted Mfsd2a knockout mice are smaller, leaner, and have decreased serum, liver and brown adipose triglycerides. Mfsd2a knockout mice have normal liver lipid metabolism but increased whole body energy expenditure, likely due to increased β-oxidation in brown adipose tissue and significantly increased voluntary movement, but surprisingly exhibited a form of ataxia. Together, these results indicate that MFSD2A is a nutritionally regulated gene that plays myriad roles in body growth and development, motor function, and lipid metabolism. Moreover, these data suggest that the ligand(s) that are transported by MFSD2A play important roles in these physiological processes and await future identification.
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Affiliation(s)
- Justin H. Berger
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Maureen J. Charron
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Medicine, Division of Endocrinology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Obstetrics and Gynecology and Women’s Health, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - David L. Silver
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Signature Research Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School, Singapore, Singapore
- * E-mail:
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TXNIP in Agrp neurons regulates adiposity, energy expenditure, and central leptin sensitivity. J Neurosci 2012; 32:9870-7. [PMID: 22815502 DOI: 10.1523/jneurosci.0353-12.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Thioredoxin interacting protein (TXNIP) has recently been described as a key regulator of energy metabolism through pleiotropic actions that include nutrient sensing in the mediobasal hypothalamus (MBH). However, the role of TXNIP in neurochemically specific hypothalamic subpopulations and the circuits downstream from MBH TXNIP engaged to regulate energy homeostasis remain unexplored. To evaluate the metabolic role of TXNIP activity specifically within arcuate Agrp neurons, we generated Agrp-specific TXNIP gain-of-function and loss-of-function mouse models using Agrp-Ires-cre mice, TXNIP (flox/flox) mice, and a lentivector expressing the human TXNIP isoform conditionally in the presence of Cre recombinase. Overexpression of TXNIP in Agrp neurons predisposed to diet-induced obesity and adipose tissue storage by decreasing energy expenditure and spontaneous locomotion, without affecting food intake. Conversely, Agrp neuronal TXNIP deletion protected against diet-induced obesity and adipose tissue storage by increasing energy expenditure and spontaneous locomotion, also without affecting food intake. TXNIP overexpression in Agrp neurons did not primarily affect glycemic control, whereas deletion of TXNIP in Agrp neurons improved fasting glucose levels and glucose tolerance independently of its effects on body weight and adiposity. Bidirectional manipulation of TXNIP expression induced reciprocal changes in central leptin sensitivity and the neural regulation of lipolysis. Together, these results identify a critical role for TXNIP in Agrp neurons in mediating diet-induced obesity through the regulation of energy expenditure and adipose tissue metabolism, independently of food intake. They also reveal a previously unidentified role for Agrp neurons in the brain-adipose axis.
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Spencer P, Fry RC, Kisby GE. Unraveling 50-Year-Old Clues Linking Neurodegeneration and Cancer to Cycad Toxins: Are microRNAs Common Mediators? Front Genet 2012; 3:192. [PMID: 23060898 PMCID: PMC3460211 DOI: 10.3389/fgene.2012.00192] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/09/2012] [Indexed: 01/19/2023] Open
Abstract
Recognition of overlapping molecular signaling activated by a chemical trigger of cancer and neurodegeneration is new, but the path to this discovery has been long and potholed. Six conferences (1962–1972) examined the puzzling neurotoxic and carcinogenic properties of a then-novel toxin [cycasin: methylazoxymethanol (MAM)-β-d-glucoside] in cycad plants used traditionally for food and medicine on Guam where a complex neurodegenerative disease plagued the indigenous population. Affected families showed combinations of amyotrophic lateral sclerosis (ALS), parkinsonism (P), and/or a dementia (D) akin to Alzheimer’s disease (AD). Modernization saw declining disease rates on Guam and remarkable changes in clinical phenotype (ALS was replaced by P-D and then by D) and in two genetically distinct ALS-PDC-affected populations (Kii-Japan, West Papua-Indonesia) that used cycad seed medicinally. MAM forms DNA lesions – repaired by O6-methylguanine methyltransferase (MGMT) – that perturb mouse brain development and induce malignant tumors in peripheral organs. The brains of young adult MGMT-deficient mice given a single dose of MAM show DNA lesion-linked changes in cell-signaling pathways associated with miRNA-1, which is implicated in colon, liver, and prostate cancers, and in neurological disease, notably AD. MAM is metabolized to formaldehyde, a human carcinogen. Formaldehyde-responsive miRNAs predicted to modulate MAM-associated genes in the brains of MGMT-deficient mice include miR-17-5p and miR-18d, which regulate genes involved in tumor suppression, DNA repair, amyloid deposition, and neurotransmission. These findings marry cycad-associated ALS-PDC with colon, liver, and prostate cancer; they also add to evidence linking changes in microRNA status both to ALS, AD, and parkinsonism, and to cancer initiation and progression.
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Affiliation(s)
- Peter Spencer
- Global Health Center, Oregon Health and Science University Portland, OR, USA
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Fould B, Lamamy V, Guenin SP, Ouvry C, Cogé F, Boutin JA, Ferry G. Mutagenic analysis in a pure molecular system shows that thioredoxin-interacting protein residue Cys247 is necessary and sufficient for a mixed disulfide formation with thioredoxin. Protein Sci 2012; 21:1323-33. [PMID: 22760822 DOI: 10.1002/pro.2119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Accepted: 06/28/2012] [Indexed: 11/11/2022]
Abstract
The human thioredoxin (TRX)-interacting protein is found in multiple subcellular compartments and plays a major role in redox homeostasis, particularly in the context of metabolism (e.g., lipidemia and glycemia) and apoptosis. A molecular approach to the protein's modus operandi is still needed because some aspects of the TRX-interacting protein-mediated regulation of TRX are not clearly understood. To this end, His-tagged TRX-interacting proteins were over-expressed in Escherichia coli. Because the protein is expressed mainly in inclusion bodies, it was denatured in high concentrations of guanidium hydrochloride, centrifuged, and purified by Ni-NTA affinity chromatography. His-TRX-interacting protein was then refolded by dialysis and its restructuring monitored by circular dichroism spectrometry. This preparation resulted in the formation of a covalent complex with recombinant human TRX, demonstrating that association occurs without the intervention of other partner proteins. Multiple cysteine-to-serine mutants of TRX-interacting protein were produced and purified. These mutations were efficient in limiting the formation of disulfide-linked homo-oligomers in an oxidizing environment. The mutants were also used to gain functional insight into the formation of the TRX-interacting protein-TRX complexes. These complexes were able to form in the absence of internal disulfide bridges. A mutant with all but one cysteine changed to serine (Cys ²⁴⁷) also showed an enhanced capacity to form complexes with TRX demonstrating, in a pure molecular system, that this particular cysteine is likely responsible for the disulfide bridge between TRX-interacting protein and TRX.
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Affiliation(s)
- Benjamin Fould
- Biotechnologies & Pharmacologie Moléculaire et Cellulaire, Institut de Recherches Servier, 125 Chemin de Ronde, 78290 Croissy-sur-Seine, France
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Patwari P, Lee RT. An expanded family of arrestins regulate metabolism. Trends Endocrinol Metab 2012; 23:216-22. [PMID: 22520962 PMCID: PMC3348262 DOI: 10.1016/j.tem.2012.03.003] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/13/2012] [Accepted: 03/13/2012] [Indexed: 11/24/2022]
Abstract
The classical visual and β-arrestins belong to a larger family of proteins that likely share structural similarity. Humans have an additional six related proteins sometimes termed the α-arrestins, whose functions are now emerging. Surprisingly, several α-arrestins play prominent roles in the regulation of metabolism and obesity. One α-arrestin, thioredoxin-interacting protein (Txnip), has crucial functions in regulating glucose uptake and glycolytic flux through the mitochondria. Another α-arrestin, Arrdc3, is linked to obesity in men and was recently identified in mice as a regulator of body mass, adiposity, and energy expenditure. Here we discuss recent evidence suggesting potential common themes for all arrestins, including physiological roles for classical arrestins in metabolism and the functions of α-arrestins in receptor signaling and endocytosis.
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Affiliation(s)
- Parth Patwari
- Harvard Stem Cell Institute and the Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, MA 02139, USA
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The Complexity of Sporadic Alzheimer's Disease Pathogenesis: The Role of RAGE as Therapeutic Target to Promote Neuroprotection by Inhibiting Neurovascular Dysfunction. Int J Alzheimers Dis 2012; 2012:734956. [PMID: 22482078 PMCID: PMC3310161 DOI: 10.1155/2012/734956] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 12/02/2011] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia. Amyloid plaques and neurofibrillary tangles are prominent pathological features of AD. Aging and age-dependent oxidative stress are the major nongenetic risk factors for AD. The beta-amyloid peptide (Aβ), the major component of plaques, and advanced glycation end products (AGEs) are key activators of plaque-associated cellular dysfunction. Aβ and AGEs bind to the receptor for AGEs (RAGE), which transmits the signal from RAGE via redox-sensitive pathways to nuclear factor kappa-B (NF-κB). RAGE-mediated signaling is an important contributor to neurodegeneration in AD. We will summarize the current knowledge and ongoing studies on RAGE function in AD. We will also present evidence for a novel pathway induced by RAGE in AD, which leads to the expression of thioredoxin interacting protein (TXNIP), providing further evidence that pharmacological inhibition of RAGE will promote neuroprotection by blocking neurovascular dysfunction in AD.
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Chutkow WA, Lee RT. Thioredoxin regulates adipogenesis through thioredoxin-interacting protein (Txnip) protein stability. J Biol Chem 2011; 286:29139-29145. [PMID: 21705327 DOI: 10.1074/jbc.m111.267666] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Txnip (thioredoxin-interacting protein) is a critical mediator of metabolism and adipogenesis in vivo. The mechanisms of action of Txnip are believed to operate at least in part by inhibiting the redox signaling functions of thioredoxin. We tested here whether Txnip suppressed adipogenesis by inhibiting thioredoxin and discovered a reversal of roles; Txnip inhibits adipogenesis directly, and thioredoxin binding regulates Txnip by enhancing Txnip protein stability. Unlike Txnip, a Txnip mutant that cannot bind thioredoxin (C247S) did not prevent adipocyte differentiation, but was degraded more quickly by proteasomal targeting. Finding that endogenous Txnip protein is also rapidly degraded at the onset of adipogenesis suggested that Txnip degradation is required for adipocyte differentiation. Thioredoxin overexpression stabilized Txnip protein levels to inhibit adipogenesis, and adipogenic stimulants such as insulin promoted Txnip-thioredoxin dissociation to the more labile free Txnip state. As an α-arrestin protein, Txnip has two C-terminal tail PPXY motifs that mediate E3 ubiquitin ligase binding and Txnip protein stability. Mutating the PPXY motifs prevented Txnip degradation, even when thioredoxin binding was lost, and restored the ability of C247S Txnip to inhibit adipogenesis. These studies present a novel reconsideration of Txnip-thioredoxin signaling by showing that thioredoxin regulates the intrinsic function of Txnip as an inhibitor of adipogenesis through protein stabilization.
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Affiliation(s)
- William A Chutkow
- Harvard Stem Cell Institute and the Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115 and; Veterans Healthcare System, West Roxbury, Massachusetts 02132.
| | - Richard T Lee
- Harvard Stem Cell Institute and the Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115 and
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