1
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Elmansi AM, Miller RA. Coordinated transcriptional upregulation of oxidative metabolism proteins in long-lived endocrine mutant mice. GeroScience 2023; 45:2967-2981. [PMID: 37273159 PMCID: PMC10643730 DOI: 10.1007/s11357-023-00849-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 05/31/2023] [Indexed: 06/06/2023] Open
Abstract
Caloric restriction (CR), which extends lifespan in rodents, leads to increased hepatic fatty acid β-oxidation and oxidative phosphorylation (OXPHOS), with parallel changes in proteins and their mRNAs. Genetic mutants that extend lifespan, including growth hormone receptor knockout (GHRKO) and Snell dwarf (SD) mice, have lower respiratory quotient, suggesting increased reliance on fatty acid oxidation, but the molecular mechanism(s) of this metabolic shift have not yet been worked out. Here we show that both GHRKO and SD mice have significantly higher mRNA and protein levels of enzymes involved in mitochondrial and peroxisomal fatty acid β-oxidation. In addition, multiple subunits of OXPHOS complexes I-IV are upregulated in GHRKO and SD livers, and Complex V subunit ATP5a is upregulated in liver of GHRKO mice. Expression of these genes is regulated by a group of nuclear receptors and transcription factors including peroxisome proliferator-activated receptors (PPARs) and estrogen-related receptors (ERRs). We found that levels of these nuclear receptors and their co-activator PGC-1α were unchanged or downregulated in liver of GHRKO and SD mice. In contrast, NCOR1, a co-repressor for the same receptors, was significantly downregulated in the two long-lived mouse models, suggesting a plausible mechanism for the changes in FAO and OXPHOS proteins. Hepatic levels of HDAC3, a co-factor for NCOR1 transcriptional repression, were also downregulated. The role of NCOR1 is well established in the contexts of cancer and metabolic disease, but may provide new mechanistic insights into metabolic control in long-lived mouse models.
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Affiliation(s)
- Ahmed M Elmansi
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Richard A Miller
- Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
- University of Michigan Geriatrics Center, Ann Arbor, MI, USA.
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2
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Peroxisome Proliferator-Activated Receptors as Molecular Links between Caloric Restriction and Circadian Rhythm. Nutrients 2020; 12:nu12113476. [PMID: 33198317 PMCID: PMC7696073 DOI: 10.3390/nu12113476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
The circadian rhythm plays a chief role in the adaptation of all bodily processes to internal and environmental changes on the daily basis. Next to light/dark phases, feeding patterns constitute the most essential element entraining daily oscillations, and therefore, timely and appropriate restrictive diets have a great capacity to restore the circadian rhythm. One of the restrictive nutritional approaches, caloric restriction (CR) achieves stunning results in extending health span and life span via coordinated changes in multiple biological functions from the molecular, cellular, to the whole-body levels. The main molecular pathways affected by CR include mTOR, insulin signaling, AMPK, and sirtuins. Members of the family of nuclear receptors, the three peroxisome proliferator-activated receptors (PPARs), PPARα, PPARβ/δ, and PPARγ take part in the modulation of these pathways. In this non-systematic review, we describe the molecular interconnection between circadian rhythm, CR-associated pathways, and PPARs. Further, we identify a link between circadian rhythm and the outcomes of CR on the whole-body level including oxidative stress, inflammation, and aging. Since PPARs contribute to many changes triggered by CR, we discuss the potential involvement of PPARs in bridging CR and circadian rhythm.
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3
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Peroxisome Proliferator-Activated Receptors and Caloric Restriction-Common Pathways Affecting Metabolism, Health, and Longevity. Cells 2020; 9:cells9071708. [PMID: 32708786 PMCID: PMC7407644 DOI: 10.3390/cells9071708] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
Caloric restriction (CR) is a traditional but scientifically verified approach to promoting health and increasing lifespan. CR exerts its effects through multiple molecular pathways that trigger major metabolic adaptations. It influences key nutrient and energy-sensing pathways including mammalian target of rapamycin, Sirtuin 1, AMP-activated protein kinase, and insulin signaling, ultimately resulting in reductions in basic metabolic rate, inflammation, and oxidative stress, as well as increased autophagy and mitochondrial efficiency. CR shares multiple overlapping pathways with peroxisome proliferator-activated receptors (PPARs), particularly in energy metabolism and inflammation. Consequently, several lines of evidence suggest that PPARs might be indispensable for beneficial outcomes related to CR. In this review, we present the available evidence for the interconnection between CR and PPARs, highlighting their shared pathways and analyzing their interaction. We also discuss the possible contributions of PPARs to the effects of CR on whole organism outcomes.
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4
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Derous D, Mitchell SE, Green CL, Wang Y, Han JDJ, Chen L, Promislow DEL, Lusseau D, Douglas A, Speakman JR. The Effects of Graded Levels of Calorie Restriction: X. Transcriptomic Responses of Epididymal Adipose Tissue. J Gerontol A Biol Sci Med Sci 2019; 73:279-288. [PMID: 28575190 PMCID: PMC5861923 DOI: 10.1093/gerona/glx101] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 02/06/2023] Open
Abstract
Calorie restriction (CR) leads to a remarkable decrease in adipose tissue mass and increases longevity in many taxa. Since the discovery of leptin, the secretory abilities of adipose tissue have gained prominence in the responses to CR. We quantified transcripts of epididymal white adipose tissue of male C57BL/6 mice exposed to graded levels of CR (0–40% CR) for 3 months. The numbers of differentially expressed genes (DEGs) involved in NF-κB, HIF1-α, and p53 signaling increased with increasing levels of CR. These pathways were all significantly downregulated at 40% CR relative to 12 h ad libitum feeding. In addition, graded CR had a substantial impact on DEGs associated with pathways involved in angiogenesis. Of the 497 genes differentially expressed with graded CR, 155 of these genes included a signal peptide motif. These putative signaling proteins were involved in the response to ketones, TGF-β signaling, negative regulation of insulin secretion, and inflammation. This accords with the previously established effects of graded CR on glucose homeostasis in the same mice. Overall these data suggest reduced levels of adipose tissue under CR may contribute to the protective impact of CR in multiple ways linked to changes in a large population of secreted proteins.
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Affiliation(s)
- Davina Derous
- Institute of Biological and Environmental Sciences, University of Aberdeen, UK
- Centre for Genome Enabled Biology and Medicine, University of Aberdeen, UK
| | - Sharon E Mitchell
- Institute of Biological and Environmental Sciences, University of Aberdeen, UK
| | - Cara L Green
- Institute of Biological and Environmental Sciences, University of Aberdeen, UK
| | - Yingchun Wang
- State Key laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, China
| | - Jing Dong J Han
- Chinese Academy of Sciences Key Laboratory of Computational Biology, Chinese Academy of Sciences, Max Planck Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China
| | - Luonan Chen
- Key laboratory of Systems Biology, Innovation Center for Cell Signalling Network, Institute of Biochemistry and Cell Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, China
| | - Daniel E L Promislow
- Department of Pathology, University of Washington, Seattle
- Department of Biology, University of Washington, Seattle
| | - David Lusseau
- Institute of Biological and Environmental Sciences, University of Aberdeen, UK
| | - Alex Douglas
- Institute of Biological and Environmental Sciences, University of Aberdeen, UK
- Centre for Genome Enabled Biology and Medicine, University of Aberdeen, UK
| | - John R Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, UK
- State Key laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Chaoyang, Beijing, China
- Address correspondence to: John R. Speakman, PhD, DSc, Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK. E-mail:
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5
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Hayashi Y, Ito Y, Naito H, Tamada H, Yamagishi N, Kondo T, Ishikawa T, Gonzalez FJ, Nakajima T. In utero exposure to di(2-ethylhexyl)phthalate suppresses blood glucose and leptin levels in the offspring of wild-type mice. Toxicology 2019; 415:49-55. [PMID: 30660623 DOI: 10.1016/j.tox.2019.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 01/11/2019] [Accepted: 01/14/2019] [Indexed: 01/09/2023]
Abstract
Exposure of pregnant mice to di(2-ethylhexyl)phthalate (DEHP) induces maternal lipid malnutrition and decreases the number of live fetuses/pups. In this study, we aimed to clarify the relationship between maternal lipid malnutrition and the nutritional status of the neonatal, lactational, and adult offspring, as well as the role of peroxisome proliferator-activated receptor α (PPARα) in these relationships. Sv/129 wild-type (mPPARA), Ppara-null, and PPARα-humanized (hPPARA) mice were fed diets containing 0, 0.01, 0.05, or 0.1% DEHP in utero and/or during the lactational stage. The male offspring were killed on postnatal day 2 or 21, or after 11 weeks. Exposure to either 0.05% or 0.1% DEHP during both the in utero and lactational periods decreased serum glucose concentrations in 2-day-old mPPARA offspring. These dosages also decreased both serum and plasma leptin levels in both 2- and 21-day-old mPPARA offspring. In contrast, exposure to DEHP only during the lactational period did not decrease leptin levels, suggesting the importance of in utero exposure to DEHP. Exposure to 0.05% DEHP during the in utero and lactational periods also increased food consumption after weaning in both mPPARA and hPPARA mice; this was not observed in Ppara-null offspring. In conclusion, in utero exposure to DEHP induces neonatal serum glucose malnutrition via PPARα. DEHP also decreases serum and plasma leptin concentrations in offspring during the neonatal and weaning periods, in association with PPARα, which presumably results in increased of food consumption after weaning.
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Affiliation(s)
- Yumi Hayashi
- Pathophysiological Laboratory Sciences, Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, 461-8673, Japan; In vivo Real-time Omics Laboratory, Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan.
| | - Yuki Ito
- Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
| | - Hisao Naito
- Department of Public Health, Fujita Health University School of Medicine, Dengakugakubo 1-98, Kutsukake-cho, Toyoake, 470-1192, Japan.
| | - Hazuki Tamada
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Nozomi Yamagishi
- Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Takaaki Kondo
- Pathophysiological Laboratory Sciences, Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, 461-8673, Japan.
| | - Tetsuya Ishikawa
- Pathophysiological Laboratory Sciences, Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, 461-8673, Japan.
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Tamie Nakajima
- College of Life and Health Sciences, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan.
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6
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Moreno-Fernandez ME, Giles DA, Stankiewicz TE, Sheridan R, Karns R, Cappelletti M, Lampe K, Mukherjee R, Sina C, Sallese A, Bridges JP, Hogan SP, Aronow BJ, Hoebe K, Divanovic S. Peroxisomal β-oxidation regulates whole body metabolism, inflammatory vigor, and pathogenesis of nonalcoholic fatty liver disease. JCI Insight 2018; 3:93626. [PMID: 29563328 DOI: 10.1172/jci.insight.93626] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 02/08/2018] [Indexed: 12/14/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), a metabolic predisposition for development of hepatocellular carcinoma (HCC), represents a disease spectrum ranging from steatosis to steatohepatitis to cirrhosis. Acox1, a rate-limiting enzyme in peroxisomal fatty acid β-oxidation, regulates metabolism, spontaneous hepatic steatosis, and hepatocellular damage over time. However, it is unknown whether Acox1 modulates inflammation relevant to NAFLD pathogenesis or if Acox1-associated metabolic and inflammatory derangements uncover and accelerate potential for NAFLD progression. Here, we show that mice with a point mutation in Acox1 (Acox1Lampe1) exhibited altered cellular metabolism, modified T cell polarization, and exacerbated immune cell inflammatory potential. Further, in context of a brief obesogenic diet stress, NAFLD progression associated with Acox1 mutation resulted in significantly accelerated and exacerbated hepatocellular damage via induction of profound histological changes in hepatocytes, hepatic inflammation, and robust upregulation of gene expression associated with HCC development. Collectively, these data demonstrate that β-oxidation links metabolism and immune responsiveness and that a better understanding of peroxisomal β-oxidation may allow for discovery of mechanisms central for NAFLD progression.
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Affiliation(s)
- Maria E Moreno-Fernandez
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Daniel A Giles
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA.,Immunology Graduate Program, CCHMC, and the University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Traci E Stankiewicz
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Rachel Sheridan
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Pathology, CCHMC, Cincinnati, Ohio, USA
| | - Rebekah Karns
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Gastroenterology, Hepatology, and Nutrition, CCHMC, Cincinnati, Ohio, USA
| | - Monica Cappelletti
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Kristin Lampe
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Rajib Mukherjee
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Christian Sina
- Molecular Gastroenterology, University Hospital Schleswig-Holstein, Campus Lübeck, Germany
| | - Anthony Sallese
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Neonatology and Pulmonary Biology
| | - James P Bridges
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Neonatology and Pulmonary Biology
| | - Simon P Hogan
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Allergy and Immunology, and
| | - Bruce J Aronow
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Biomedical Informatics, CCHMC, Cincinnati, Ohio, USA
| | - Kasper Hoebe
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
| | - Senad Divanovic
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center (CCHMC), Cincinnati, Ohio, USA
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7
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Brown-Borg HM, Buffenstein R. Cutting back on the essentials: Can manipulating intake of specific amino acids modulate health and lifespan? Ageing Res Rev 2017; 39:87-95. [PMID: 27570078 DOI: 10.1016/j.arr.2016.08.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 08/24/2016] [Accepted: 08/24/2016] [Indexed: 12/26/2022]
Abstract
With few exceptions, nutritional and dietary interventions generally impact upon both old-age quality of life and longevity. The life prolonging effects, commonly observed with dietary restriction reportedly are linked to alterations in protein intake and specifically limiting the dietary intake of certain essential amino acids. There is however a paucity of data methodically evaluating the various essential amino acids on health- and lifespan and the mechanisms involved. Rodent diets containing either lower methionine content, or tryptophan, than that found in commercially available chow, appear to elicit beneficial effects. It is unclear whether all of these favorable effects associated with restricted intake of methionine and tryptophan are due to their specific unique properties or if restriction of other essential amino acids, or proteins in general, may produce similar results. Considerably more work remains to be done to elucidate the mechanisms by which limiting these vital molecules may delay the onset of age-associated diseases and improve quality of life at older ages.
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8
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PPARα-independent transcriptional targets of perfluoroalkyl acids revealed by transcript profiling. Toxicology 2017; 387:95-107. [PMID: 28558994 DOI: 10.1016/j.tox.2017.05.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 01/09/2023]
Abstract
Perfluoroalkyl acids (PFAAs) are ubiquitous and persistent environmental contaminants. Compounds such as perfluoroocanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), and perfluorohexane sulfonate (PFHxS) are readily found in the tissues of humans and wildlife. While PFOA and PFOS have been the subject of numerous studies since they were first described over a decade ago, less is known about the biological activity of PFHxS and PFNA. Most PFAAs are activators of peroxisome proliferator-activated receptor α (PPARα), although the biological effects of these compounds are likely mediated by other factors in addition to PPARα. To evaluate the effects of PFHxS and PFNA, male wild-type and Pparα-null mice were dosed by oral gavage with PFHxS (3 or 10mg/kg/day), PFNA (1 or 3mg/kg/day), or vehicle for 7days, and liver gene expression was evaluated by full-genome microarrays. Gene expression patterns were then compared to historical in-house data for PFOA and PFOS in addition to the experimental hypolipidemic agent, WY-14,643. While WY-14,643 altered most genes in a PPARα-dependent manner, approximately 11-24% of regulated genes in PFAA-treated mice were independent of PPARα. The possibility that PFAAs regulate gene expression through other molecular pathways was evaluated. Using data available through a microarray database, PFAA gene expression profiles were found to exhibit significant similarity to profiles from mouse tissues exposed to agonists of the constitutive activated receptor (CAR), estrogen receptor α (ERα), and PPARγ. Human PPARγ and ERα were activated by all four PFAAs in trans-activation assays from the ToxCast screening program. Predictive gene expression biomarkers showed that PFAAs activate CAR in both genotypes and cause feminization of the liver transcriptome through suppression of signal transducer and activator of transcription 5B (STAT5B). These results indicate that, in addition to activating PPARα as a primary target, PFAAs also have the potential to activate CAR, PPARγ, and ERα as well as suppress STAT5B.
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9
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Dominick G, Bowman J, Li X, Miller RA, Garcia GG. mTOR regulates the expression of DNA damage response enzymes in long-lived Snell dwarf, GHRKO, and PAPPA-KO mice. Aging Cell 2017; 16:52-60. [PMID: 27618784 PMCID: PMC5242303 DOI: 10.1111/acel.12525] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2016] [Indexed: 01/05/2023] Open
Abstract
Studies of the mTOR pathway have prompted speculation that diminished mTOR complex‐1 (mTORC1) function may be involved in controlling the aging process. Our previous studies have shown diminished mTORC1 activity in tissues of three long‐lived mutant mice: Snell dwarf mice, growth hormone receptor gene disrupted mice (GHRKO), and in this article, mice deficient in the pregnancy‐associated protein‐A (PAPPA‐KO). The ways in which lower mTOR signals slow aging and age‐related diseases are, however, not well characterized. Here, we show that Snell, GHKRO, and PAPPA‐KO mice express high levels of two proteins involved in DNA repair, O‐6‐methylguanine‐DNA methyltransferase (MGMT) and N‐myc downstream‐regulated gene 1 (NDRG1). Furthermore, we report that lowering mTOR enhances MGMT and NDRG1 protein expression via post‐transcriptional mechanisms. We show that the CCR4‐NOT complex, a post‐transcriptional regulator of gene expression, is downstream of the mTORC1 pathway and may be responsible for the upregulation of MGMT and NDRG1 in all three varieties of long‐lived mice. Our data thus suggest a novel link between DNA repair and mTOR signaling via post‐transcriptional regulation involving specific alteration in the CCR4‐NOT complex, whose modulation could control multiple aspects of the aging process.
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Affiliation(s)
- Graham Dominick
- Department of Molecular, Cellular, and Developmental Biology; University of Michigan College of Literature, Science and the Arts; Ann Arbor MI USA
| | - Jacqueline Bowman
- Department of Molecular, Cellular, and Developmental Biology; University of Michigan College of Literature, Science and the Arts; Ann Arbor MI USA
| | - Xinna Li
- Department of Pathology; University of Michigan School of Medicine; Ann Arbor MI USA
| | - Richard A. Miller
- Department of Pathology; University of Michigan School of Medicine; Ann Arbor MI USA
- University of Michigan Geriatrics Center; Ann Arbor MI USA
| | - Gonzalo G. Garcia
- Department of Pathology; University of Michigan School of Medicine; Ann Arbor MI USA
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10
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Chemical and Hormonal Effects on STAT5b-Dependent Sexual Dimorphism of the Liver Transcriptome. PLoS One 2016; 11:e0150284. [PMID: 26959237 PMCID: PMC4784907 DOI: 10.1371/journal.pone.0150284] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 02/11/2016] [Indexed: 12/21/2022] Open
Abstract
The growth hormone (GH)-activated transcription factor signal transducer and activator of transcription 5b (STAT5b) is a key regulator of sexually dimorphic gene expression in the liver. Suppression of hepatic STAT5b signaling is associated with lipid metabolic dysfunction leading to steatosis and liver cancer. In the companion publication, a STAT5b biomarker gene set was identified and used in a rank-based test to predict both increases and decreases in liver STAT5b activation status/function with high (≥ 97%) accuracy. Here, this computational approach was used to identify chemicals and hormones that activate (masculinize) or suppress (feminize) STAT5b function in a large, annotated mouse liver and primary hepatocyte gene expression compendium. Exposure to dihydrotestosterone and thyroid hormone caused liver masculinization, whereas glucocorticoids, fibroblast growth factor 15, and angiotensin II caused liver feminization. In mouse models of diabetes and obesity, liver feminization was consistently observed and was at least partially reversed by leptin or resveratrol exposure. Chemical-induced feminization of male mouse liver gene expression profiles was a relatively frequent phenomenon: of 156 gene expression biosets from chemically-treated male mice, 29% showed feminization of liver STAT5b function, while <1% showed masculinization. Most (93%) of the biosets that exhibited feminization of male liver were also associated with activation of one or more xenobiotic-responsive receptors, most commonly constitutive activated receptor (CAR) or peroxisome proliferator-activated receptor alpha (PPARα). Feminization was consistently associated with increased expression of peroxisome proliferator-activated receptor gamma (Pparg) but not other lipogenic transcription factors linked to steatosis. GH-activated STAT5b signaling in mouse liver is thus commonly altered by diverse chemicals, and provides a linkage between chemical exposure and dysregulated gene expression associated with adverse effects on the liver.
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11
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Brown-Borg HM. Reduced growth hormone signaling and methionine restriction: interventions that improve metabolic health and extend life span. Ann N Y Acad Sci 2015; 1363:40-9. [PMID: 26645136 DOI: 10.1111/nyas.12971] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 10/11/2015] [Accepted: 10/22/2015] [Indexed: 02/06/2023]
Abstract
Interventions that improve health are often associated with longevity. Reduced growth hormone signaling has been shown to increase life span in mice by over 50%. Similarly, reductions in dietary intake of methionine, in rats and mice, result in life-span extension. Many factors affect metabolic health, mitochondrial function, and resistance to stressors, each of which influence aging and life span. This paper presents a comparison of these two interventions, as well as the results of a study combining these interventions, to understand potential mechanisms underlying their effectiveness in enhancing healthy aging.
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Affiliation(s)
- Holly M Brown-Borg
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota
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12
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Abstract
The somatotropic signaling pathway has been implicated in aging and longevity studies in mice and other species. The physiology and lifespans of a variety of mutant mice, both spontaneous and genetically engineered, have contributed to our current understanding of the role of growth hormone and insulin-like growth factor I on aging-related processes. Several other mice discovered to live longer than their wild-type control counterparts also exhibit differences in growth factor levels; however, the complex nature of the phenotypic changes in these animals may also impact lifespan. The somatotropic axis impacts several pathways that dictate insulin sensitivity, nutrient sensing, mitochondrial function, and stress resistance as well as others that are thought to be involved in lifespan regulation.
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Affiliation(s)
- H M Brown-Borg
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, North Dakota
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13
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Pickering AM, Lehr M, Miller RA. Lifespan of mice and primates correlates with immunoproteasome expression. J Clin Invest 2015; 125:2059-68. [PMID: 25866968 PMCID: PMC4463211 DOI: 10.1172/jci80514] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/05/2015] [Indexed: 12/24/2022] Open
Abstract
There is large variation in lifespan among different species, and there is evidence that modulation of proteasome function may contribute to longevity determination. Comparative biology provides a powerful tool for identifying genes and pathways that control the rate of aging. Here, we evaluated skin-derived fibroblasts and demonstrate that among primate species, longevity correlated with an elevation in proteasomal activity as well as immunoproteasome expression at both the mRNA and protein levels. Immunoproteasome enhancement occurred with a concurrent increase in other elements involved in MHC class I antigen presentation, including β-2 microglobulin, (TAP1), and TAP2. Fibroblasts from long-lived primates also appeared more responsive to IFN-γ than cells from short-lived primate species, and this increase in IFN-γ responsiveness correlated with elevated expression of the IFN-γ receptor protein IFNGR2. Elevation of immunoproteasome and proteasome activity was also observed in the livers of long-lived Snell dwarf mice and in mice exposed to drugs that have been shown to extend lifespan, including rapamycin, 17-α-estradiol, and nordihydroguaiaretic acid. This work suggests that augmented immunoproteasome function may contribute to lifespan differences in mice and among primate species.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 2
- ATP Binding Cassette Transporter, Subfamily B, Member 3
- ATP-Binding Cassette Transporters/biosynthesis
- ATP-Binding Cassette Transporters/genetics
- Animals
- Antigen Presentation
- Cells, Cultured
- Dwarfism/genetics
- Dwarfism/physiopathology
- Estradiol/pharmacology
- Female
- Fibroblasts/cytology
- Fibroblasts/drug effects
- Fibroblasts/metabolism
- Gene Expression Regulation
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class I/metabolism
- Interferon-gamma/pharmacology
- Janus Kinases/physiology
- Longevity/drug effects
- Longevity/immunology
- Longevity/physiology
- Male
- Masoprocol/pharmacology
- Mice/physiology
- Mice, Inbred C3H
- Mice, Mutant Strains
- Oxidative Stress
- Primates/physiology
- Proteasome Endopeptidase Complex/biosynthesis
- Proteasome Endopeptidase Complex/chemistry
- Proteasome Endopeptidase Complex/genetics
- Proteasome Endopeptidase Complex/metabolism
- Protein Subunits
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Interferon/physiology
- STAT Transcription Factors/physiology
- Signal Transduction
- Sirolimus/pharmacology
- Species Specificity
- Up-Regulation
- beta 2-Microglobulin/biosynthesis
- beta 2-Microglobulin/genetics
- Interferon gamma Receptor
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14
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Larsen MC, Bushkofsky JR, Gorman T, Adhami V, Mukhtar H, Wang S, Reeder SB, Sheibani N, Jefcoate CR. Cytochrome P450 1B1: An unexpected modulator of liver fatty acid homeostasis. Arch Biochem Biophys 2015; 571:21-39. [PMID: 25703193 DOI: 10.1016/j.abb.2015.02.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 01/23/2015] [Accepted: 02/10/2015] [Indexed: 12/12/2022]
Abstract
Cytochrome P450 1b1 (Cyp1b1) expression is absent in mouse hepatocytes, but present in liver endothelia and activated stellate cells. Increased expression during adipogenesis suggests a role of Cyp1b1 metabolism in fatty acid homeostasis. Wild-type C57BL/6j (WT) and Cyp1b1-null (Cyp1b1-ko) mice were provided low or high fat diets (LFD and HFD, respectively). Cyp1b1-deletion suppressed HFD-induced obesity, improved glucose tolerance and prevented liver steatosis. Suppression of lipid droplets in sinusoidal hepatocytes, concomitant with enhanced glycogen granules, was a consistent feature of Cyp1b1-ko mice. Cyp1b1 deletion altered the in vivo expression of 560 liver genes, including suppression of PPARγ, stearoyl CoA desaturase 1 (Scd1) and many genes stimulated by PPARα, each consistent with this switch in energy storage mechanism. Ligand activation of PPARα in Cyp1b1-ko mice by WY-14643 was, nevertheless, effective. Seventeen gene changes in Cyp1b1-ko mice correspond to mouse transgenic expression that attenuated diet-induced diabetes. The absence of Cyp1b1 in mouse hepatocytes indicates participation in energy homeostasis through extra-hepatocyte signaling. Extensive sexual dimorphism in hepatic gene expression suggests a developmental impact of estrogen metabolism by Cyp1b1. Suppression of Scd1 and increased leptin turnover support enhanced leptin participation from the hypothalamus. Cyp1b1-mediated effects on vascular cells may underlie these changes.
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Affiliation(s)
- Michele Campaigne Larsen
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States
| | - Justin R Bushkofsky
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States
| | - Tyler Gorman
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States
| | - Vaqar Adhami
- Department of Dermatology, University of Wisconsin, Madison, WI 53706, United States
| | - Hasan Mukhtar
- Department of Dermatology, University of Wisconsin, Madison, WI 53706, United States
| | - Suqing Wang
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States
| | - Scott B Reeder
- Department of Radiology, University of Wisconsin, Madison, WI 53706, United States; Department of Medical Physics, University of Wisconsin, Madison, WI 53706, United States; Department of Biomedical Engineering, University of Wisconsin, Madison, WI 53706, United States; Department of Medicine, University of Wisconsin, Madison, WI 53706, United States; Department of Emergency Medicine, University of Wisconsin, Madison, WI 53706, United States
| | - Nader Sheibani
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, WI 53706, United States
| | - Colin R Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, WI 53706, United States; Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53706, United States; Endocrinology and Reproductive Physiology Program, University of Wisconsin, Madison, WI 53706, United States.
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15
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Brown-Borg HM, Rakoczy S, Wonderlich JA, Armstrong V, Rojanathammanee L. Altered dietary methionine differentially impacts glutathione and methionine metabolism in long-living growth hormone-deficient Ames dwarf and wild-type mice. LONGEVITY & HEALTHSPAN 2014; 3:10. [PMID: 25584190 PMCID: PMC4290132 DOI: 10.1186/2046-2395-3-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/01/2014] [Indexed: 02/05/2023]
Abstract
Background Extending mammalian health span and life span has been achieved under a variety of dietary restriction protocols. Reducing the intake of a specific amino acid has also been shown to extend health and longevity. We recently reported that methionine (MET) restriction is not effective in life span extension in growth hormone (GH) signaling mutants. To better understand the apparent necessity of GH in the ‘sensing’ of altered dietary MET, the current study was designed to evaluate MET and glutathione (GSH) metabolism (as well as other pathways) in long-living GH-deficient Ames dwarf and wild-type mice following 8 weeks of restricted (0.16%), low (0.43%), or enriched (1.3%) dietary MET consumption. Metabolite expression was examined in liver tissue, while gene and protein expression were evaluated in liver, kidney, and muscle tissues. Results Body weight was maintained in dwarf mice on the MET diets, while wild-type mice on higher levels of MET gained weight. Liver MET levels were similar in Ames mice, while several MET pathway enzymes were elevated regardless of dietary MET intake. Transsulfuration enzymes were also elevated in Ames mice but differences in cysteine levels were not different between genotypes. Dwarf mice maintained higher levels of GSH on MET restriction compared to wild-type mice, while genotype and diet effects were also detected in thioredoxin and glutaredoxin. MET restriction increased transmethylation in both genotypes as indicated by increased S-adenosylmethionine (SAM), betaine, and dimethylglycine. Diet did not impact levels of glycolytic components, but dwarf mice exhibited higher levels of key members of this pathway. Coenzyme A and measures of fatty acid oxidation were elevated in dwarf mice and unaffected by diet. Conclusions This component analysis between Ames and wild-type mice suggests that the life span differences observed may result from the atypical MET metabolism and downstream effects on multiple systems. The overall lack of responsiveness to the different diets is well reflected across many metabolic pathways in dwarf mice indicating the importance of GH signaling in the ability to discriminate dietary amino acid levels. Electronic supplementary material The online version of this article (doi:10.1186/2046-2395-3-10) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Holly M Brown-Borg
- Department of Basic Sciences, University of North Dakota School of Medicine & Health Sciences, 501 N. Columbia Road, Grand Forks, ND 58203 USA
| | - Sharlene Rakoczy
- Department of Basic Sciences, University of North Dakota School of Medicine & Health Sciences, 501 N. Columbia Road, Grand Forks, ND 58203 USA
| | - Joseph A Wonderlich
- Department of Basic Sciences, University of North Dakota School of Medicine & Health Sciences, 501 N. Columbia Road, Grand Forks, ND 58203 USA
| | - Vanessa Armstrong
- Department of Basic Sciences, University of North Dakota School of Medicine & Health Sciences, 501 N. Columbia Road, Grand Forks, ND 58203 USA
| | - Lalida Rojanathammanee
- Department of Basic Sciences, University of North Dakota School of Medicine & Health Sciences, 501 N. Columbia Road, Grand Forks, ND 58203 USA ; School of Sports Science, Institute of Science, Suranaree University of Technology, Muang District, Nakhon Ratchasima, 30000 Thailand
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16
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Brown-Borg HM, Rakoczy SG, Wonderlich JA, Rojanathammanee L, Kopchick JJ, Armstrong V, Raasakka D. Growth hormone signaling is necessary for lifespan extension by dietary methionine. Aging Cell 2014; 13:1019-27. [PMID: 25234161 PMCID: PMC4244257 DOI: 10.1111/acel.12269] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2014] [Indexed: 11/29/2022] Open
Abstract
Growth hormone significantly impacts lifespan in mammals. Mouse longevity is extended when growth hormone (GH) signaling is interrupted but markedly shortened with high-plasma hormone levels. Methionine metabolism is enhanced in growth hormone deficiency, for example, in the Ames dwarf, but suppressed in GH transgenic mice. Methionine intake affects also lifespan, and thus, GH mutant mice and respective wild-type littermates were fed 0.16%, 0.43%, or 1.3% methionine to evaluate the interaction between hormone status and methionine. All wild-type and GH transgenic mice lived longer when fed 0.16% methionine but not when fed higher levels. In contrast, animals without growth hormone signaling due to hormone deficiency or resistance did not respond to altered levels of methionine in terms of lifespan, body weight, or food consumption. Taken together, our results suggest that the presence of growth hormone is necessary to sense dietary methionine changes, thus strongly linking growth and lifespan to amino acid availability.
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Affiliation(s)
- Holly M Brown-Borg
- Department of Basic Sciences, University of North Dakota School of Medicine and Health SciencesGrand Forks, ND, 58203, USA
| | - Sharlene G Rakoczy
- Department of Basic Sciences, University of North Dakota School of Medicine and Health SciencesGrand Forks, ND, 58203, USA
| | - Joseph A Wonderlich
- Department of Basic Sciences, University of North Dakota School of Medicine and Health SciencesGrand Forks, ND, 58203, USA
| | - Lalida Rojanathammanee
- Department of Basic Sciences, University of North Dakota School of Medicine and Health SciencesGrand Forks, ND, 58203, USA
| | - John J Kopchick
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Edison Biotechnology Institute, Ohio UniversityAthens, OH, 45701, USA
| | - Vanessa Armstrong
- Department of Basic Sciences, University of North Dakota School of Medicine and Health SciencesGrand Forks, ND, 58203, USA
| | - Debbie Raasakka
- Department of Basic Sciences, University of North Dakota School of Medicine and Health SciencesGrand Forks, ND, 58203, USA
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17
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Corton JC, Cunningham ML, Hummer BT, Lau C, Meek B, Peters JM, Popp JA, Rhomberg L, Seed J, Klaunig JE. Mode of action framework analysis for receptor-mediated toxicity: The peroxisome proliferator-activated receptor alpha (PPARα) as a case study. Crit Rev Toxicol 2013; 44:1-49. [PMID: 24180432 DOI: 10.3109/10408444.2013.835784] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Several therapeutic agents and industrial chemicals induce liver tumors in rodents through the activation of the peroxisome proliferator-activated receptor alpha (PPARα). The cellular and molecular events by which PPARα activators induce rodent hepatocarcinogenesis has been extensively studied and elucidated. This review summarizes the weight of evidence relevant to the hypothesized mode of action (MOA) for PPARα activator-induced rodent hepatocarcinogenesis and identifies gaps in our knowledge of this MOA. Chemical-specific and mechanistic data support concordance of temporal and dose-response relationships for the key events associated with many PPARα activators including a phthalate ester plasticizer di(2-ethylhexyl) phthalate (DEHP) and the drug gemfibrozil. While biologically plausible in humans, the hypothesized key events in the rodent MOA, for PPARα activators, are unlikely to induce liver tumors in humans because of toxicodynamic and biological differences in responses. This conclusion is based on minimal or no effects observed on growth pathways, hepatocellular proliferation and liver tumors in humans and/or species (including hamsters, guinea pigs and cynomolgous monkeys) that are more appropriate human surrogates than mice and rats at overlapping dose levels. Overall, the panel concluded that significant quantitative differences in PPARα activator-induced effects related to liver cancer formation exist between rodents and humans. On the basis of these quantitative differences, most of the workgroup felt that the rodent MOA is "not relevant to humans" with the remaining members concluding that the MOA is "unlikely to be relevant to humans". The two groups differed in their level of confidence based on perceived limitations of the quantitative and mechanistic knowledge of the species differences, which for some panel members strongly supports but cannot preclude the absence of effects under unlikely exposure scenarios.
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18
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Hennessey JC, McGuire JJ. Attenuated vasodilator effectiveness of protease-activated receptor 2 agonist in heterozygous par2 knockout mice. PLoS One 2013; 8:e55965. [PMID: 23409098 PMCID: PMC3567012 DOI: 10.1371/journal.pone.0055965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/03/2013] [Indexed: 01/20/2023] Open
Abstract
Studies of homozygous PAR2 gene knockout mice have described a mix of phenotypic effects in vitro and in vivo. However, there have been few studies of PAR2 heterozygous (wild-type/knockout; PAR2-HET) mice. The phenotypes of many hemi and heterozygous transgenic mice have been described as intermediates between those of wild-type and knockout animals. In our study we aimed to determine the effects of intermediary par2 gene zygosity on vascular tissue responses to PAR2 activation. Specifically, we compared the vasodilator effectiveness of the PAR2 activating peptide 2-furoyl-LIGRLO-amide in aortas of wild-type PAR2 homozygous (PAR2-WT) and PAR2-HET mice. In myographs under isometric tension conditions, isolated aortic rings were contracted by alpha 1-adrenoeceptor agonist (phenylephrine), and thromboxane receptor agonist (U46619) and then relaxation responses by the additions of 2-furoyl-LIGRLO-amide, acetylcholine, and nitroprusside were recorded. A Schild regression analysis of the inhibition by a PAR2 antagonist (GB-83) of PAR2 agonist-induced aortic ring relaxations was used to compare receptor expression in PAR2-WT to PAR2-HET. PAR2 mRNA in aortas was measured by quantitative real-time PCR. In aortas contracted by either phenylephrine or U46619, the maximum relaxations induced by 2-furoyl-LIGRLO-amide were less in PAR2-HET than in the gender-matched PAR2-WT. GB-83 was 3- to 4-fold more potent for inhibition of 2fly in PAR2-HET than in PAR2-WT. PAR2 mRNA content of aortas from PAR2-HET was not significantly different than in PAR2-WT. Acetylcholine- and nitroprusside-induced relaxations of aortas from PAR2-HET were not significantly different than in PAR2-WT and PAR2 knockout. An interesting secondary finding was that relaxations induced by agonists of PAR2 and muscarinic receptors were larger in females than in males. We conclude that the lower PAR2-mediated responses in PAR2-HET aortas are consistent with evidence of a lower quantity of functional receptor expression, despite the apparently normal PAR2 mRNA content in PAR2-HET aortas.
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Affiliation(s)
- John C. Hennessey
- Cardiovascular Research Group, Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | - John J. McGuire
- Cardiovascular Research Group, Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
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19
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Fernández-Pérez L, Guerra B, Díaz-Chico JC, Flores-Morales A. Estrogens regulate the hepatic effects of growth hormone, a hormonal interplay with multiple fates. Front Endocrinol (Lausanne) 2013; 4:66. [PMID: 23761784 PMCID: PMC3670000 DOI: 10.3389/fendo.2013.00066] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/20/2013] [Indexed: 12/28/2022] Open
Abstract
The liver responds to estrogens and growth hormone (GH) which are critical regulators of body growth, gender-related hepatic functions, and intermediate metabolism. The effects of estrogens on liver can be direct, through the direct actions of hepatic ER, or indirect, which include the crosstalk with endocrine, metabolic, and sex-differentiated functions of GH. Most previous studies have been focused on the influence of estrogens on pituitary GH secretion, which has a great impact on hepatic transcriptional regulation. However, there is strong evidence that estrogens can influence the GH-regulated endocrine and metabolic functions in the human liver by acting at the level of GHR-STAT5 signaling pathway. This crosstalk is relevant because the widespread exposition of estrogen or estrogen-related compounds in human. Therefore, GH or estrogen signaling deficiency as well as the influence of estrogens on GH biology can cause a dramatic impact in liver physiology during mammalian development and in adulthood. In this review, we will summarize the current status of the influence of estrogen on GH actions in liver. A better understanding of estrogen-GH interplay in liver will lead to improved therapy of children with growth disorders and of adults with GH deficiency.
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Affiliation(s)
- Leandro Fernández-Pérez
- Oncology-Molecular and Translational Endocrinology Group, Clinical Sciences Department, Faculty of Health Sciences, Associate Unit of University of Las Palmas de Gran Canaria and Biomedical Institute “Alberto Sols”-CSIC, Las Palmas de Gran Canaria, Spain
- *Correspondence: Leandro Fernández-Pérez, Molecular and Translational Endocrinology Group, Department of Clinical Sciences and Pharmacology, Health Sciences Center, University of Las Palmas de Gran Canaria, Campus of San Cristobal, 35016 Las Palmas de Gran Canaria, Spain e-mail:
| | - Borja Guerra
- Oncology-Molecular and Translational Endocrinology Group, Clinical Sciences Department, Faculty of Health Sciences, Associate Unit of University of Las Palmas de Gran Canaria and Biomedical Institute “Alberto Sols”-CSIC, Las Palmas de Gran Canaria, Spain
| | - Juan C. Díaz-Chico
- Oncology-Molecular and Translational Endocrinology Group, Clinical Sciences Department, Faculty of Health Sciences, Associate Unit of University of Las Palmas de Gran Canaria and Biomedical Institute “Alberto Sols”-CSIC, Las Palmas de Gran Canaria, Spain
| | - A. Flores-Morales
- Molecular Endocrinology Group, Novo Nordisk Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
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20
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Brown-Borg HM, Johnson WT, Rakoczy SG. Expression of oxidative phosphorylation components in mitochondria of long-living Ames dwarf mice. AGE (DORDRECHT, NETHERLANDS) 2012; 34:43-57. [PMID: 21327718 PMCID: PMC3260352 DOI: 10.1007/s11357-011-9212-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 01/24/2011] [Indexed: 05/30/2023]
Abstract
Reduced signaling of the growth hormone (GH)/insulin-like growth factor-1 (IGF-1) pathway is associated with extended life span in several species. Ames dwarf mice are GH-deficient and live >50% longer than wild-type littermates. Previously, we have shown that tissues from Ames mice exhibit elevated levels of antioxidative enzymes, less H(2)O(2) production, and lower oxidative damage suggesting that mitochondrial function may differ between genotypes. To explore the relationship between hormone deficiency and mitochondria in mice with extended longevity, we evaluated activity, protein, and gene expression of oxidative phosphorylation components in dwarf and wild-type mice at varying ages. Liver complex I + III activity was higher in dwarf mice compared to wild-type mice. The activity of I + III decreased between 3 and 20 months of age in both genotypes with greater declines in wild-type mice in liver and skeletal muscle. Complex IV activities in the kidney were elevated in 3- and 20-month-old dwarf mice relative to wild-type mice. In Ames mice, protein levels of the 39 kDa complex I subunit were elevated at 20 months of age when compared to wild-type mouse mitochondria for every tissue examined. Kidney and liver mitochondria from 20-month-old dwarf mice had elevated levels of both mitochondrially-encoded and nuclear-encoded complex IV proteins compared to wild-type mice (p < 0.05). Higher liver ANT1 and PGC-1α mRNA levels were also observed in dwarf mice. Overall, we found that several components of the oxidative phosphorylation (OXPHOS) system were elevated in Ames mice. Mitochondrial to nuclear DNA ratios were not different between genotypes despite the marked increase in PGC-1α levels in dwarf mice. The increased OXPHOS activities, along with lower ROS production in dwarf mice, predict enhanced mitochondrial function and efficiency, two factors likely contributing to long-life in Ames mice.
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Affiliation(s)
- Holly M Brown-Borg
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 N. Columbia Rd, Grand Forks, ND 58203, USA.
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21
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Masternak MM, Bartke A. PPARs in Calorie Restricted and Genetically Long-Lived Mice. PPAR Res 2011; 2007:28436. [PMID: 17389764 PMCID: PMC1779582 DOI: 10.1155/2007/28436] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2006] [Revised: 10/18/2006] [Accepted: 10/18/2006] [Indexed: 01/29/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptors superfamily. The three subtypes, PPARα, PPARγ, and PPARβ/δ, are expressed in multiple organs. These transcription factors regulate different physiological
functions such as energy metabolism (including lipid and carbohydrate metabolism), insulin action, and immunity and inflammation, and apparently also act as important mediators of longevity and aging. Calorie restriction (CR) is the most effective intervention known to delay aging and increase lifespan.
Calorie restriction affects the same physiological functions as PPARs. This review summarizes recent
findings on the effects of CR and aging on the expression of PPARγ, α, and β/δ in mice and discusses possible involvement of PPARs in mediating the effects of murine longevity genes. The levels of PPARs change with age and CR appears to prevent these alterations which make “PPARs-CR-AGING” dependence of considerable interest.
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Affiliation(s)
- Michal M. Masternak
- Departments of Internal Medicine, Geriatrics Research, School of Medicine, Southern Illinois University, Springfield, IL 62794, USA
- *Michal M. Masternak:
| | - Andrzej Bartke
- Departments of Internal Medicine, Geriatrics Research, School of Medicine, Southern Illinois University, Springfield, IL 62794, USA
- Departments of Physiology, Geriatrics Research, School of Medicine, Southern Illinois University, Springfield, IL 62794, USA
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22
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The Functions of PPARs in Aging and Longevity. PPAR Res 2011; 2007:39654. [PMID: 18317516 PMCID: PMC2254525 DOI: 10.1155/2007/39654] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 07/23/2007] [Accepted: 09/14/2007] [Indexed: 12/21/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are key regulators in various age-associated pathophysiological processes related to energy metabolism and oxidative stress. A progressive rise of oxidative stress and related inflammatory reaction appears the hallmarks of the aging process and many age-related diseases. PPARs are important redox-sensitive
transcription factors and their dyregulated activations seem to be major culprits for these
pathological processes. Drugs targeting PPARs activity are already in widespread clinical use;
however, based on these concepts, this review highlights the understanding of the role of
PPARs in aging and indicates the necessary particular attention for the potential therapeutic
uses of current PPAR agonists in age-associated diseases.
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23
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List EO, Sackmann-Sala L, Berryman DE, Funk K, Kelder B, Gosney ES, Okada S, Ding J, Cruz-Topete D, Kopchick JJ. Endocrine parameters and phenotypes of the growth hormone receptor gene disrupted (GHR-/-) mouse. Endocr Rev 2011; 32:356-86. [PMID: 21123740 PMCID: PMC3365798 DOI: 10.1210/er.2010-0009] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Disruption of the GH receptor (GHR) gene eliminates GH-induced intracellular signaling and, thus, its biological actions. Therefore, the GHR gene disrupted mouse (GHR-/-) has been and is a valuable tool for helping to define various parameters of GH physiology. Since its creation in 1995, this mouse strain has been used by our laboratory and others for numerous studies ranging from growth to aging. Some of the most notable discoveries are their extreme insulin sensitivity in the presence of obesity. Also, the animals have an extended lifespan, which has generated a large number of investigations into the roles of GH and IGF-I in the aging process. This review summarizes the many results derived from the GHR-/- mice. We have attempted to present the findings in the context of current knowledge regarding GH action and, where applicable, to discuss how these mice compare to GH insensitivity syndrome in humans.
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Affiliation(s)
- Edward O List
- The Edison Biotechnology Institute, Ohio University, Athens, Ohio 45701, USA
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24
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Motoyama K, Nakai Y, Miyashita T, Fukui Y, Morita M, Sanmiya K, Sakakibara H, Matsumoto I, Abe K, Yakabe T, Yajima N, Shimoi K. Isolation stress for 30 days alters hepatic gene expression profiles, especially with reference to lipid metabolism in mice. Physiol Genomics 2008; 37:79-87. [PMID: 19106182 DOI: 10.1152/physiolgenomics.90358.2008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
To elucidate the physiological responses to a social stressor, we exposed mice to an isolation stress and analyzed their hepatic gene expression profiles using a DNA microarray. Male BALB/c mice were exposed to isolation stress for 30 days, and then hepatic RNA was sampled and subjected to DNA microarray analysis. The isolation stress altered the expression of 420 genes (after considering the false discovery rate). Gene Ontology analysis of these differentially expressed genes indicated that the stress remarkably downregulated the lipid metabolism-related pathway through peroxisome proliferator-activated receptor-alpha, while the lipid biosynthesis pathway controlled by sterol regulatory element binding factor 1, Golgi vesicle transport, and secretory pathway-related genes were significantly upregulated. These results suggest that isolation for 30 days with a mild and consecutive social stress regulates the systems for lipid metabolism and also causes endoplasmic reticulum stress in mouse liver.
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Affiliation(s)
- Keiko Motoyama
- Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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25
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Alderman JM, Flurkey K, Brooks NL, Naik SB, Gutierrez JM, Srinivas U, Ziara KB, Jing L, Boysen G, Bronson R, Klebanov S, Chen X, Swenberg JA, Stridsberg M, Parker CE, Harrison DE, Combs TP. Neuroendocrine inhibition of glucose production and resistance to cancer in dwarf mice. Exp Gerontol 2008; 44:26-33. [PMID: 18582556 DOI: 10.1016/j.exger.2008.05.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 05/23/2008] [Accepted: 05/27/2008] [Indexed: 10/22/2022]
Abstract
Pit1 null (Snell dwarf) and Proph1 null (Ames dwarf) mutant mice lack GH, PRL and TSH. Snell and Ames dwarf mice also exhibit reduced IGF-I, resistance to cancer and a longer lifespan than control mice. Endogenous glucose production during fasting is reduced in Snell dwarf mice compared to fasting control mice. In view of cancer cell dependence on glucose for energy, low endogenous glucose production may provide Snell dwarf mice with resistance to cancer. We investigated whether endogenous glucose production is lower in Snell dwarf mice during feeding. Inhibition of endogenous glucose production by glucose injection was enhanced in 12 to 14 month-old female Snell dwarf mice. Thus, we hypothesize that lower endogenous glucose production during feeding and fasting reduces cancer cell glucose utilization providing Snell dwarf mice with resistance to cancer. The elevation of circulating adiponectin, a hormone produced by adipose tissue, may contribute to the suppression of endogenous glucose production in 12 to 14 month-old Snell dwarf mice. We compared the incidence of cancer at time of death between old Snell dwarf and control mice. Only 18% of old Snell dwarf mice had malignant lesions at the time of death compared to 82% of control mice. The median ages at death for old Snell dwarf and control mice were 33 and 26 months, respectively. By contrast, previous studies showed a high incidence of cancer in old Ames dwarf mice at the time of death. Hence, resistance to cancer in old Snell dwarf mice may be mediated by neuroendocrine factors that reduce glucose utilization besides elevated adiponectin, reduced IGF-I and a lack of GH, PRL and TSH, seen in both Snell and Ames dwarf mice. Proteomics analysis of pituitary secretions from Snell dwarf mice confirmed the absence of GH and PRL, the secretion of ACTH and elevated secretion of Chromogranin B and Secretogranin II. Radioimmune assays confirmed that circulating Chromogranin B and Secretogranin II were elevated in 12 to 14 month-old Snell dwarf mice. In summary, our results in Snell dwarf mice suggest that the pituitary gland and adipose tissue are part of a neuroendocrine loop that lowers the risk of cancer during aging by reducing the availability of glucose.
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Biserni A, Giannessi F, Sciarroni AF, Milazzo FM, Maggi A, Ciana P. In Vivo Imaging Reveals Selective Peroxisome Proliferator Activated Receptor Modulator Activity of the Synthetic Ligand 3-(1-(4-Chlorobenzyl)-3-t-butylthio-5-isopropylindol-2-yl)-2,2-dimethylpropanoic acid (MK-886). Mol Pharmacol 2008; 73:1434-43. [DOI: 10.1124/mol.107.042689] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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27
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Brooks NL, Trent CM, Raetzsch CF, Flurkey K, Boysen G, Perfetti MT, Jeong YC, Klebanov S, Patel KB, Khodush VR, Kupper LL, Carling D, Swenberg JA, Harrison DE, Combs TP. Low Utilization of Circulating Glucose after Food Withdrawal in Snell Dwarf Mice. J Biol Chem 2007; 282:35069-77. [PMID: 17905742 DOI: 10.1074/jbc.m700484200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glucose metabolism is altered in long-lived people and mice. Although it is clear that there is an association between altered glucose metabolism and longevity, it is not known whether this link is causal or not. Our current hypothesis is that decreased fasting glucose utilization may increase longevity by reducing oxygen radical production, a potential cause of aging. We observed that whole body fasting glucose utilization was lower in the Snell dwarf, a long-lived mutant mouse. Whole body fasting glucose utilization may be reduced by a decrease in the production of circulating glucose. Our isotope labeling analysis indicated both gluconeogenesis and glycogenolysis were suppressed in Snell dwarfs. Elevated circulating adiponectin may contribute to the reduction of glucose production in Snell dwarfs. Adiponectin lowered the appearance of glucose in the media over hepatoma cells by suppressing gluconeogenesis and glycogenolysis. The suppression of glucose production by adiponectin in vitro depended on AMP-activated protein kinase, a cell mediator of fatty acid oxidation. Elevated fatty acid oxidation was indicated in Snell dwarfs by increased utilization of circulating oleic acid, reduced intracellular triglyceride content, and increased phosphorylation of acetyl-CoA carboxylase. Finally, protein carbonyl content, a marker of oxygen radical damage, was decreased in Snell dwarfs. The correlation between high glucose utilization and elevated oxygen radical production was also observed in vitro by altering the concentrations of glucose and fatty acids in the media or pharmacologic inhibition of glucose and fatty acid oxidation with 4-hydroxycyanocinnamic acid and etomoxir, respectively.
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Affiliation(s)
- Natasha L Brooks
- Department of Nutrition, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Rosen MB, Thibodeaux JR, Wood CR, Zehr RD, Schmid JE, Lau C. Gene expression profiling in the lung and liver of PFOA-exposed mouse fetuses. Toxicology 2007; 239:15-33. [PMID: 17681415 DOI: 10.1016/j.tox.2007.06.095] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 06/06/2007] [Accepted: 06/15/2007] [Indexed: 11/26/2022]
Abstract
Perfluorooctanoic acid (PFOA) is a stable perfluoroalkyl acid used to synthesize fluoropolymers during the manufacture of a wide variety of products. Concerns have been raised over the potential health effects of PFOA because it is persistent in the environment and can be detected in blood and other tissues of many animal species, including humans. PFOA has also been shown to induce growth deficits and mortality in murine neonates. To better understand the mechanism of PFOA induced developmental toxicity, lung and liver gene expression profiling was conducted in PFOA-exposed full-term mouse fetuses. Thirty timed-pregnant CD-1 mice were orally dosed from gestation days 1-17 with either 0, 1, 3, 5, or 10mg/(kgday) PFOA in water. At term, fetal lung and liver were collected, total RNA prepared, and samples pooled from three fetuses per litter. Five biological replicates consisting of individual litter samples were then evaluated for each treatment group using Affymetrix mouse 430_2 microarrays. The expression of genes related to fatty acid catabolism was altered in both the fetal liver and lung. In the fetal liver, the effects of PFOA were robust and also included genes associated with lipid transport, ketogenesis, glucose metabolism, lipoprotein metabolism, cholesterol biosynthesis, steroid metabolism, bile acid biosynthesis, phospholipid metabolism, retinol metabolism, proteosome activation, and inflammation. These changes are consistent with transactivation of PPARalpha, although, with regard to bile acid biosynthesis and glucose metabolism, non-PPARalpha related effects were suggested as well. Additional studies will be needed to more thoroughly address the role of PPARalpha, and other nuclear receptors, in PFOA mediated developmental toxicity.
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Affiliation(s)
- Mitchell B Rosen
- Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Yang Q, Nagano T, Shah Y, Cheung C, Ito S, Gonzalez FJ. The PPAR alpha-humanized mouse: a model to investigate species differences in liver toxicity mediated by PPAR alpha. Toxicol Sci 2007; 101:132-9. [PMID: 17690133 PMCID: PMC2197159 DOI: 10.1093/toxsci/kfm206] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To determine the impact of the species difference between rodents and humans in response to peroxisome proliferators (PPs) mediated by peroxisome proliferator-activated receptor (PPAR)alpha, PPAR alpha-humanized transgenic mice were generated using a P1 phage artificial chromosome (PAC) genomic clone bred onto a ppar alpha-null mouse background, designated hPPAR alpha PAC. In hPPAR alpha PAC mice, the human PPAR alpha gene is expressed in tissues with high fatty acid catabolism and induced upon fasting, similar to mouse PPAR alpha in wild-type (Wt) mice. Upon treatment with the PP fenofibrate, hPPAR alpha PAC mice exhibited responses similar to Wt mice, including peroxisome proliferation, lowering of serum triglycerides, and induction of PPAR alpha target genes encoding enzymes involved in fatty acid metabolism in liver, kidney, and heart, suggesting that human PPAR alpha (hPPAR alpha) functions in the same manner as mouse PPAR alpha in regulating fatty acid metabolism and lowering serum triglycerides. However, in contrast to Wt mice, treatment of hPPAR alpha PAC mice with fenofibrate did not cause significant hepatomegaly and hepatocyte proliferation, thus indicating that the mechanisms by which PPAR alpha affects lipid metabolism are distinct from the hepatocyte proliferation response, the latter of which is only induced by mouse PPAR alpha. In addition, a differential regulation of several genes, including the oncogenic let-7C miRNA by PPs, was observed between Wt and hPPAR alpha PAC mice that may contribute to the inherent difference between mouse and human PPAR alpha in activation of hepatocellular proliferation. The hPPAR alpha PAC mouse model provides an in vivo platform to investigate the species difference mediated by PPAR alpha and an ideal model for human risk assessment PPs exposure.
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Affiliation(s)
| | | | | | | | | | - Frank J. Gonzalez
- To whom correspondence should be addressed. Frank J. Gonzalez, Building 37, Room 3106, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892. Fax: (301) 496-8419. E-mail:
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30
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The PPAR alpha-humanized mouse: a model to investigate species differences in liver toxicity mediated by PPAR alpha. Toxicol Sci 2007. [PMID: 17690133 DOI: 10.1093toxsci/kfm206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
To determine the impact of the species difference between rodents and humans in response to peroxisome proliferators (PPs) mediated by peroxisome proliferator-activated receptor (PPAR)alpha, PPAR alpha-humanized transgenic mice were generated using a P1 phage artificial chromosome (PAC) genomic clone bred onto a ppar alpha-null mouse background, designated hPPAR alpha PAC. In hPPAR alpha PAC mice, the human PPAR alpha gene is expressed in tissues with high fatty acid catabolism and induced upon fasting, similar to mouse PPAR alpha in wild-type (Wt) mice. Upon treatment with the PP fenofibrate, hPPAR alpha PAC mice exhibited responses similar to Wt mice, including peroxisome proliferation, lowering of serum triglycerides, and induction of PPAR alpha target genes encoding enzymes involved in fatty acid metabolism in liver, kidney, and heart, suggesting that human PPAR alpha (hPPAR alpha) functions in the same manner as mouse PPAR alpha in regulating fatty acid metabolism and lowering serum triglycerides. However, in contrast to Wt mice, treatment of hPPAR alpha PAC mice with fenofibrate did not cause significant hepatomegaly and hepatocyte proliferation, thus indicating that the mechanisms by which PPAR alpha affects lipid metabolism are distinct from the hepatocyte proliferation response, the latter of which is only induced by mouse PPAR alpha. In addition, a differential regulation of several genes, including the oncogenic let-7C miRNA by PPs, was observed between Wt and hPPAR alpha PAC mice that may contribute to the inherent difference between mouse and human PPAR alpha in activation of hepatocellular proliferation. The hPPAR alpha PAC mouse model provides an in vivo platform to investigate the species difference mediated by PPAR alpha and an ideal model for human risk assessment PPs exposure.
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31
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Ciana P, Biserni A, Tatangelo L, Tiveron C, Sciarroni AF, Ottobrini L, Maggi A. A Novel Peroxisome Proliferator-Activated Receptor Responsive Element-Luciferase Reporter Mouse Reveals Gender Specificity of Peroxisome Proliferator-Activated Receptor Activity in Liver. Mol Endocrinol 2007; 21:388-400. [PMID: 17158222 DOI: 10.1210/me.2006-0152] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
There is a growing interest in peroxisome proliferator-activated receptors (PPARs) as major players in the regulation of lipid and carbohydrate metabolism. Drugs targeting PPARs were in fact shown to have major relevance for the treatment of diseases associated with aging, such as arteriosclerosis and diabetes. However, a variety of toxic effects associated with PPAR ligand administration has been documented, including hepatocarcinogenesis, which may severely limit its therapeutic use. A better comprehension of the multiplicity of PPAR physiological functions is therefore mandatory for the development of novel, safer drugs. We here describe the generation of a novel transgenic mouse for the detection of the generalized activities of PPARs, the PPAR responsive element-Luc reporter mouse. In this model luciferase expression is under the control of a PPAR-inducible promoter in all target organs. By optical imaging and ex vivo analysis, we were able to demonstrate the remarkable gender specificity of the PPAR transcriptional activity in liver. In fact, in the liver of female PPAR responsive element-Luc, the PPAR reporter transgene is more than one order of magnitude less expressed, thus leading to the conclusion that the signaling in females is much less activated than in males. Diet or hormonal manipulations as demonstrated here by treatments with high-fat diet or gonad removal and hormone replacement do not influence this low activation. The extent of the gender difference in PPAR transcriptional activity and the ineffectiveness of hormone treatments or diet to significantly elevate liver PPAR activity in females led us to hypothesize that gender-specific epigenetic events occurring during development may affect PPAR signaling in the liver. This study sets the ground for understanding the differential susceptibility of the two genders to metabolic disorders; furthermore, the model generated provides a novel opportunity for the molecular characterization of PPAR activity in pathophysiological conditions.
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Affiliation(s)
- Paolo Ciana
- Center of Excellence on Neurodegenerative Diseases, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy
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Brown-Borg HM. Longevity in mice: is stress resistance a common factor? AGE (DORDRECHT, NETHERLANDS) 2006; 28:145-162. [PMID: 19943136 PMCID: PMC2464727 DOI: 10.1007/s11357-006-9003-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 12/01/2005] [Indexed: 05/27/2023]
Abstract
A positive relationship between stress resistance and longevity has been reported in a multitude of studies in organisms ranging from yeast to mice. Several mouse lines have been discovered or developed that exhibit extended longevities when compared with normal, wild-type mice of the same genetic background. These long-living lines include the Ames dwarf, Snell dwarf, growth hormone receptor knockout (Laron dwarf), IGF-1 receptor heterozygote, Little, alpha-MUPA knockout, p66(shc) knockout, FIRKO, mClk-1 heterozygote, thioredoxin transgenic, and most recently the Klotho transgenic mouse. These mice are described in terms of the reported extended lifespans and studies involving resistance to stress. In addition, caloric restriction (CR) and stress resistance are briefly addressed for comparison with genetically altered mice. Although many of the long-living mice have GH/IGF-1/insulin signaling-related alterations and enhanced stress resistance, there are some that exhibit life extension without an obvious link to this hormone pathway. Resistance to oxidative stress is by far the most common system studied in long-living mice, but there is evidence of enhancement of resistance in other systems as well. The differences in stress resistance between long-living mutant and normal mice result from complex interrelationships among pathways that appear to coordinate signals of growth and metabolism, and subsequently result in differences in lifespan.
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Affiliation(s)
- H M Brown-Borg
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58203, USA.
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Yoon A, Peng G, Brandenburger Y, Brandenburg Y, Zollo O, Xu W, Rego E, Ruggero D. Impaired control of IRES-mediated translation in X-linked dyskeratosis congenita. Science 2006; 312:902-6. [PMID: 16690864 DOI: 10.1126/science.1123835] [Citation(s) in RCA: 315] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The DKC1 gene encodes a pseudouridine synthase that modifies ribosomal RNA (rRNA). DKC1 is mutated in people with X-linked dyskeratosis congenita (X-DC), a disease characterized by bone marrow failure, skin abnormalities, and increased susceptibility to cancer. How alterations in ribosome modification might lead to cancer and other features of the disease remains unknown. Using an unbiased proteomics strategy, we discovered a specific defect in IRES (internal ribosome entry site)-dependent translation in Dkc1(m) mice and in cells from X-DC patients. This defect results in impaired translation of messenger RNAs containing IRES elements, including those encoding the tumor suppressor p27(Kip1) and the antiapoptotic factors Bcl-xL and XIAP (X-linked Inhibitor of Apoptosis Protein). Moreover, Dkc1(m) ribosomes were unable to direct translation from IRES elements present in viral messenger RNAs. These findings reveal a potential mechanism by which defective ribosome activity leads to disease and cancer.
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Affiliation(s)
- Andrew Yoon
- Human Genetics Program, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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Harper JM, Salmon AB, Chang Y, Bonkowski M, Bartke A, Miller RA. Stress resistance and aging: influence of genes and nutrition. Mech Ageing Dev 2006; 127:687-94. [PMID: 16713617 PMCID: PMC2923407 DOI: 10.1016/j.mad.2006.04.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 04/03/2006] [Accepted: 04/12/2006] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that dermal fibroblast cell lines derived from young adult mice of the long-lived Snell dwarf (dw/dw), Ames dwarf (df/df) and growth hormone receptor knockout (GHR-KO) mouse stocks are resistant, in vitro, to the cytotoxic effects of hydrogen peroxide, cadmium, ultraviolet light, paraquat, and heat. Here we show that, in contrast, fibroblasts from mice on low-calorie (CR) or low methionine (Meth-R) diets are not stress resistant in culture, despite the longevity induced by both dietary regimes. A second approach, involving induction of liver cell death in live animals using acetaminophen (APAP), documented hepatotoxin resistance in the CR and Meth-R mice, but dw/dw and GHR-KO mutant mice were not resistant to this agent, and were in fact more susceptible than littermate controls to the toxic effects of APAP. These data thus suggest that while resistance to stress is a common characteristic of experimental life span extension in mice, the cell types showing resistance may differ among the various models of delayed or decelerated aging.
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Affiliation(s)
- James M Harper
- Department of Pathology and Geriatrics Center, University of Michigan School of Medicine, Ann Arbor, MI, United States.
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35
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Corton JC, Brown-Borg HM. Peroxisome Proliferator-Activated Receptor Coactivator 1 in Caloric Restriction and Other Models of Longevity. J Gerontol A Biol Sci Med Sci 2005; 60:1494-509. [PMID: 16424281 DOI: 10.1093/gerona/60.12.1494] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Dietary restriction of calories (caloric restriction [CR]) increases longevity in phylogenetically diverse species. CR retards or prevents age-dependent deterioration of tissues and an array of spontaneous and chemically induced diseases associated with obesity including cardiovascular disease, diabetes, and cancer. An understanding of the molecular mechanisms that underlie the beneficial effects of CR will help identify novel dietary, pharmacological, and lifestyle strategies for slowing the rate of aging and preventing these diseases as well as identify factors which modulate chemical toxicity. Here, we review the involvement of transcriptional coactivator proteins, peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1 (PGC-1) alpha and beta, and regulated nuclear receptors (NR) in mediating the phenotypic changes found in models of longevity which include rodent CR models and mouse mutants in which insulin and/or insulin-like growth factor-I signaling is attenuated. PGC-1alpha is transcriptionally or posttranslationally regulated in mammals by: 1) forkhead box "other" (FoxO) transcription factors through an insulin/insulin-like growth factor-I -dependent pathway, 2) glucagon-stimulated cellular AMP (cAMP) response element binding protein, 3) stress-activated kinase signaling through p38 mitogen-activated protein kinase, and 4) the deacetylase and longevity factor sirtuin 1 (SIRT1). PGC-1alpha and PGC-1beta regulate the ligand-dependent and -independent activation of a large number of NR including PPARalpha and constitutive activated receptor (CAR). These NR regulate genes involved in nutrient and xenobiotic transport and metabolism as well as resistance to stress. CR reverses age-dependent decreases in PGC-1alpha, PPARalpha, and regulated genes. Strategies that target one or multiple PGC-1-regulated NR could be used to mimic the beneficial health effects found in models of longevity.
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Affiliation(s)
- J Christopher Corton
- United States Environmental Protection Agency, Division of Environmental Carcinogenesis, Research Triangle Park, NC 27711, USA.
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