1
|
List EO, Basu R, Duran-Ortiz S, Krejsa J, Jensen EA. Mouse models of growth hormone deficiency. Rev Endocr Metab Disord 2021; 22:3-16. [PMID: 33033978 DOI: 10.1007/s11154-020-09601-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 01/01/2023]
Abstract
Nearly one century of research using growth hormone deficient (GHD) mouse lines has contributed greatly toward our knowledge of growth hormone (GH), a pituitary-derived hormone that binds and signals through the GH receptor and affects many metabolic processes throughout life. Although delayed sexual maturation, decreased fertility, reduced muscle mass, increased adiposity, small body size, and glucose intolerance appear to be among the negative characteristics of these GHD mouse lines, these mice still consistently outlive their normal sized littermates. Furthermore, the absence of GH action in these mouse lines leads to enhanced insulin sensitivity (likely due to the lack of GH's diabetogenic actions), delayed onset for a number of age-associated physiological declines (including cognition, cancer, and neuromusculoskeletal frailty), reduced cellular senescence, and ultimately, extended lifespan. In this review, we provide details about history, availability, growth, physiology, and aging of five commonly used GHD mouse lines.
Collapse
Affiliation(s)
- Edward O List
- The Edison Biotechnology Institute, Ohio University, 172 Water Tower Drive, Athens, OH, 45701, USA.
- The Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701, USA.
| | - Reetobrata Basu
- The Edison Biotechnology Institute, Ohio University, 172 Water Tower Drive, Athens, OH, 45701, USA
| | - Silvana Duran-Ortiz
- The Edison Biotechnology Institute, Ohio University, 172 Water Tower Drive, Athens, OH, 45701, USA
| | - Jackson Krejsa
- The Edison Biotechnology Institute, Ohio University, 172 Water Tower Drive, Athens, OH, 45701, USA
| | - Elizabeth A Jensen
- The Edison Biotechnology Institute, Ohio University, 172 Water Tower Drive, Athens, OH, 45701, USA
- The Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701, USA
| |
Collapse
|
2
|
Abstract
Reduction of insulin/insulin-like growth factor 1 (IGF1) signaling (IIS) extends the lifespan of various species. So far, several longevity mouse models have been developed containing mutations related to growth signaling deficiency by targeting growth hormone (GH), IGF1, IGF1 receptor, insulin receptor, and insulin receptor substrate. In addition, p70 ribosomal protein S6 kinase 1 (S6K1) knockout leads to lifespan extension. S6K1 encodes an important kinase in the regulation of cell growth. S6K1 is regulated by mechanistic target of rapamycin (mTOR) complex 1. The v-myc myelocytomatosis viral oncogene homolog (MYC)-deficient mice also exhibits a longevity phenotype. The gene expression profiles of these mice models have been measured to identify their longevity mechanisms. Here, we summarize our knowledge of long-lived mouse models related to growth and discuss phenotypic characteristics, including organ-specific gene expression patterns.
Collapse
Affiliation(s)
- Seung-Soo Kim
- Institute of Animal Molecular Biotechnology, Korea University, Seoul 02841, Korea
| | - Cheol-Koo Lee
- Institute of Animal Molecular Biotechnology, Korea University, Seoul 02841; Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02481, Korea
| |
Collapse
|
3
|
IGF-1 mediated phosphorylation of specific IRS-1 serines in Ames dwarf fibroblasts is associated with longevity. Oncotarget 2016; 6:35315-23. [PMID: 26474286 PMCID: PMC4742107 DOI: 10.18632/oncotarget.6112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/22/2015] [Indexed: 12/28/2022] Open
Abstract
Insulin/IGF-1 signaling involves phosphorylation/dephosphorylation of serine/threonine or tyrosine residues of the insulin receptor substrate (IRS) proteins and is associated with hormonal control of longevity determination of certain long-lived mice. The stimulation of serine phosphorylations by IGF-1 suggests there is insulin/IGF-1 crosstalk that involves the phosphorylation of the same serine residues. By this mechanism, insulin and IGF-1 mediated phosphorylation of specific IRS-1 serines could play a role in longevity determination. We used fibroblasts from WT and Ames dwarf mice to examine whether: (a) IGF-1 stimulates phosphorylation of IRS-1 serines targeted by insulin; (b) the levels of serine phosphorylation differ in WT vs. Ames fibroblasts; and (c) aging affects the levels of these serine phosphorylations which are altered in the Ames dwarf mutant. We have shown that IRS-1 is a substrate for IGF-1 induced phosphorylation of Ser307, Ser612, Ser636/639, and Ser1101; that the levels of phosphorylation of these serines are significantly lower in Ames vs. WT cells; that IGF-1 mediated phosphorylation of these serines increases with age in WT cells. We propose that insulin/IGF-1 cross talk and level of phosphorylation of specific IRS-1 serines may promote the Ames dwarf longevity phenotype.
Collapse
|
4
|
Bartke A, Westbrook R. Metabolic characteristics of long-lived mice. Front Genet 2012; 3:288. [PMID: 23248643 PMCID: PMC3521393 DOI: 10.3389/fgene.2012.00288] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/23/2012] [Indexed: 12/31/2022] Open
Abstract
Genetic suppression of insulin/insulin-like growth factor signaling (IIS) can extend longevity in worms, insects, and mammals. In laboratory mice, mutations with the greatest, most consistent, and best documented positive impact on lifespan are those that disrupt growth hormone (GH) release or actions. These mutations lead to major alterations in IIS but also have a variety of effects that are not directly related to the actions of insulin or insulin-like growth factor I. Long-lived GH-resistant GHR-KO mice with targeted disruption of the GH receptor gene, as well as Ames dwarf (Prop1df) and Snell dwarf (Pit1dw) mice lacking GH (along with prolactin and TSH), are diminutive in size and have major alterations in body composition and metabolic parameters including increased subcutaneous adiposity, increased relative brain weight, small liver, hypoinsulinemia, mild hypoglycemia, increased adiponectin levels and insulin sensitivity, and reduced serum lipids. Body temperature is reduced in Ames, Snell, and female GHR-KO mice. Indirect calorimetry revealed that both Ames dwarf and GHR-KO mice utilize more oxygen per gram (g) of body weight than sex- and age-matched normal animals from the same strain. They also have reduced respiratory quotient, implying greater reliance on fats, as opposed to carbohydrates, as an energy source. Differences in oxygen consumption (VO2) were seen in animals fed or fasted during the measurements as well as in animals that had been exposed to 30% calorie restriction or every-other-day feeding. However, at the thermoneutral temperature of 30°C, VO2 did not differ between GHR-KO and normal mice. Thus, the increased metabolic rate of the GHR-KO mice, at a standard animal room temperature of 23°C, is apparently related to increased energy demands for thermoregulation in these diminutive animals. We suspect that increased oxidative metabolism combined with enhanced fatty acid oxidation contribute to the extended longevity of GHR-KO mice.
Collapse
Affiliation(s)
- Andrzej Bartke
- Division of Geriatrics Research, Department of Internal Medicine, Southern Illinois University School of Medicine Springfield, IL, USA
| | | |
Collapse
|
5
|
Bartlett BJ, Isakson P, Lewerenz J, Sanchez H, Kotzebue RW, Cumming RC, Harris GL, Nezis IP, Schubert DR, Simonsen A, Finley KD. p62, Ref(2)P and ubiquitinated proteins are conserved markers of neuronal aging, aggregate formation and progressive autophagic defects. Autophagy 2011; 7:572-83. [PMID: 21325881 DOI: 10.4161/auto.7.6.14943] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Suppression of macroautophagy, due to mutations or through processes linked to aging, results in the accumulation of cytoplasmic substrates that are normally eliminated by the pathway. This is a significant problem in long-lived cells like neurons, where pathway defects can result in the accumulation of aggregates containing ubiquitinated proteins. The p62/Ref(2)P family of proteins is involved in the autophagic clearance of cytoplasmic protein bodies or sequestosomes. These unique structures are closely associated with protein inclusions containing ubiquitin as well as key components of the autophagy pathway. In this study we show that detergent fractionation followed by western blot analysis of insoluble ubiquitinated proteins (IUP), mammalian p62 and its Drosophila homologue, Ref(2)P can be used to quantitatively assess the activity level of aggregate clearance (aggrephagy) in complex tissues. Using this technique we show that genetic or age-dependent changes that modify the long-term enhancement or suppression of aggrephagy can be identified. Moreover, using the Drosophila model system this method can be used to establish autophagy-dependent protein clearance profiles that are occurring under a wide range of physiological conditions including developmental, fasting and altered metabolic pathways. This technique can also be used to examine proteopathies that are associated with human disorders such as frontotemporal dementia, Huntington and Alzheimer disease. Our findings indicate that measuring IUP profiles together with an assessment of p62/Ref(2)P proteins can be used as a screening or diagnostic tool to characterize genetic and age-dependent factors that alter the long-term function of autophagy and the clearance of protein aggregates occurring within complex tissues and cells.
Collapse
|
6
|
Schober ME, Block B, Beachy JC, Statler KD, Giza CC, Lane RH. Early and sustained increase in the expression of hippocampal IGF-1, but not EPO, in a developmental rodent model of traumatic brain injury. J Neurotrauma 2011; 27:2011-20. [PMID: 20822461 DOI: 10.1089/neu.2009.1226] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Pediatric traumatic brain injury (pTBI) is the leading cause of traumatic death and disability in children in the United States. Impaired learning and memory in these young survivors imposes a heavy toll on society. In adult TBI (aTBI) models, cognitive outcome improved after administration of erythropoietin (EPO) or insulin-like growth factor-1 (IGF-1). Little is known about the production of these agents in the hippocampus, a brain region critical for learning and memory, after pTBI. Our objective was to describe hippocampal expression of EPO and IGF-1, together with their receptors (EPOR and IGF-1R, respectively), over time after pTBI in 17-day-old rats. We used the controlled cortical impact (CCI) model and measured hippocampal mRNA levels of EPO, IGF-1, EPOR, IGF-1R, and markers of caspase-dependent apoptosis (bcl2, bax, and p53) at post-injury days (PID) 1, 2, 3, 7, and 14. CCI rats performed poorly on Morris water maze testing of spatial working memory, a hippocampally-based cognitive function. Apoptotic markers were present early and persisted for the duration of the study. EPO in our pTBI model increased much later (PID7) than in aTBI models (12 h), while EPOR and IGF-1 increased at PID1 and PID2, respectively, similar to data from aTBI models. Our data indicate that EPO expression showed a delayed upregulation post-pTBI, while EPOR increased early. We speculate that administration of EPO in the first 1-2 days after pTBI would increase hippocampal neuronal survival and function.
Collapse
Affiliation(s)
- Michelle E Schober
- Department of Pediatrics, Division of Critical Care, University of Utah, Salt Lake City, Utah 84158, USA.
| | | | | | | | | | | |
Collapse
|
7
|
Coyne GS, Kenny DA, Waters SM. Effect of dietary n-3 polyunsaturated fatty acid supplementation on bovine uterine endometrial and hepatic gene expression of the insulin-like growth factor system. Theriogenology 2010; 75:500-12. [PMID: 21111466 DOI: 10.1016/j.theriogenology.2010.09.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 09/14/2010] [Accepted: 09/14/2010] [Indexed: 11/30/2022]
Abstract
Supplementation of cattle diets with n-3 polyunsaturated fatty acids (n-3 PUFA) has been suggested to have positive effects on fertility. In addition, the actions of the insulin-like growth factor (IGF) system both systemically and locally have been shown to influence reproductive processes. The objective of this study was to evaluate the effect of dietary n-3 PUFA supplementation on hepatic and endometrial expression of IGF signalling genes in cattle. Beef heifers were supplemented with a rumen protected source of either a saturated fatty acid (palmitic acid; CON) or high n-3 PUFA diet (n-3 PUFA) for 45 days before slaughter and tissue recovery. Transcription level of candidate IGF signalling genes was measured by reverse transcription quantitative real-time PCR (RT-qPCR) in total RNA isolated from uterine endometrial and liver tissue from seven CON and seven n-3 PUFA supplemented animals. Compared to controls, mRNA abundance in n-3 PUFA liver tissues was higher for IGF-2R, IGFBP-1 and IGFBP-5 (P < 0.05); lower for GHR-1A (P < 0.05); and unchanged for IGF-1, IGF-2, IGF-1R, IGFBP-2, IGFBP-3, IGFBP-4, IGFBP-6, ALS and GHR(total) (P > 0.05). Compared to controls, mRNA abundance in n-3 PUFA endometrial tissues was higher for IGF-2, IGF-1R, IGF-2R and IGFBP-2 (P < 0.05); lower for IGF-1, IGFBP-3 and IGFBP-6 (P < 0.05); and unchanged for IGFBP-1, IGFBP-4, IGFBP-5 and GHR(total) (P > 0.05). Thus, dietary supplementation of cattle with n-3 PUFA affects transcription of genes involved in IGF signalling, in a tissue dependent fashion.
Collapse
Affiliation(s)
- Gerard S Coyne
- Teagasc, Animal Bioscience Centre, Dunsany, Co. Meath, Ireland
| | | | | |
Collapse
|
8
|
Schober ME, Block B, Beachy JC, Statler KD, Giza CC, Lane RH. Early and Sustained Increase in the Expression of Hippocampal IGF-1, But Not EPO, in a Developmental Rodent Model of Traumatic Brain Injury. J Neurotrauma 2010. [DOI: 10.1089/neu.2010.1226] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
9
|
Westwood M, Maqsood AR, Solomon M, Whatmore AJ, Davis JRE, Baxter RC, Gevers EF, Robinson ICAF, Clayton PE. The effect of different patterns of growth hormone administration on the IGF axis and somatic and skeletal growth of the dwarf rat. Am J Physiol Endocrinol Metab 2010; 298:E467-76. [PMID: 19861588 PMCID: PMC2838527 DOI: 10.1152/ajpendo.00234.2009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Normal childhood growth is determined by ultradian and infradian variations in GH secretion, yet GH treatment of children with short stature is restricted to daily fixed doses. We have used GH-deficient dwarf rats to determine whether variable GH dose regimens promote growth more effectively than fixed doses. Animals were treated with saline or 4.2 mg of recombinant bovine GH given as 1) 700 microg/wk in 100 microg/day doses, 2) alternating weekly doses of 966 (138 microg/day) or 434 microg (62 microg/day), or 3) 700 microg/wk in randomized daily doses (5-250 microg/day). Body weight and length were measured weekly. Femur and tibia lengths and internal organ, fat pad, and muscle weights were recorded at the end of the study (6 wk); blood was collected for IGF axis measurements. GH promoted femur [F(3,60) = 14.67, P < 0.05], tibia [F(3,60) = 14.90, P < 0.05], muscle [F(3,60) = 10.37, P < 0.05], and organ growth [liver: F(3,60) = 9.30, P < 0.05; kidney: F(3,60) = 2.82, P < 0.05] and an increase in serum IGF-I [F(3,60) = 9.18, P < 0.05] and IGFBP-3 [F(3,60) = 6.70, P < 0.05] levels. IGF-I levels correlated with final weight (r = 0.45, P < 0.05) and length (r = 0.284, P < 0.05) in the whole cohort, but within each group, growth parameters correlated with serum IGF-I only in animals treated with random GH doses. The variable regimens promoted femur length (P < 0.05) and muscle (P < 0.05) and kidney (P < 0.05) weight more effectively than treatment with the fixed regimen. This study demonstrates that aspects of growth are improved following introduction of infradian variation to GH treatment in a GH-deficient model. The data suggest that varying the pattern of GH doses administered to children may enhance growth performance without increasing the overall GH dose.
Collapse
|
10
|
Conover CA, Mason MA, Levine JA, Novak CM. Metabolic consequences of pregnancy-associated plasma protein-A deficiency in mice: exploring possible relationship to the longevity phenotype. J Endocrinol 2008; 198:599-605. [PMID: 18566100 PMCID: PMC2593875 DOI: 10.1677/joe-08-0179] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Mice born with the deletion of the gene for pregnancy-associated plasma protein-A (PAPP-A), a model of reduced local IGF activity, live approximately 30% longer than their wild-type (WT) littermates. In this study, we investigated metabolic consequences of PAPP-A gene deletion and possible relationship to lifespan extension. Specifically, we determined whether 18-month-old PAPP-A knockout (KO) mice when compared with their WT littermates have reduced energy expenditure and/or altered glucose-insulin sensitivity. Food intake, and total energy expenditure and resting energy expenditure as measured by calorimetry were not different between PAPP-A KO and WT mice when subjected to the analysis of covariance with body weight as the covariate. However, there was an increase in spontaneous physical activity in PAPP-A KO mice. Both WT and PAPP-A KO mice exhibited mild insulin resistance with age, as assessed by fasting glucose/insulin ratios. Oral glucose tolerance and insulin sensitivity were not significantly different between the two groups of mice, although there appeared to be a decrease in the average size of the pancreatic islets in PAPP-A KO mice. Thus, neither reduced 'rate of living' nor altered glucose-insulin homeostasis can be considered key determinants of the enhanced longevity of PAPP-A KO mice. These findings are discussed in the context of those from other long-lived mouse models.
Collapse
Affiliation(s)
- Cheryl A Conover
- Division of Endocrinology, Metabolism and Nutrition, Mayo Clinic, 200 First Street SW, 5-194 Joseph, Rochester, Minnesota 55905, USA.
| | | | | | | |
Collapse
|
11
|
Park JY, Cho MO, Leonard S, Calder B, Mian IS, Kim WH, Wijnhoven S, van Steeg H, Mitchell J, van der Horst GTJ, Hoeijmakers J, Cohen P, Vijg J, Suh Y. Homeostatic imbalance between apoptosis and cell renewal in the liver of premature aging Xpd mice. PLoS One 2008; 3:e2346. [PMID: 18545656 PMCID: PMC2396506 DOI: 10.1371/journal.pone.0002346] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 05/02/2008] [Indexed: 01/08/2023] Open
Abstract
Unrepaired or misrepaired DNA damage has been implicated as a causal factor in cancer and aging. Xpd(TTD) mice, harboring defects in nucleotide excision repair and transcription due to a mutation in the Xpd gene (R722W), display severe symptoms of premature aging but have a reduced incidence of cancer. To gain further insight into the molecular basis of the mutant-specific manifestation of age-related phenotypes, we used comparative microarray analysis of young and old female livers to discover gene expression signatures distinguishing Xpd(TTD) mice from their age-matched wild type controls. We found a transcription signature of increased apoptosis in the Xpd(TTD) mice, which was confirmed by in situ immunohistochemical analysis and found to be accompanied by increased proliferation. However, apoptosis rate exceeded the rate of proliferation, resulting in homeostatic imbalance. Interestingly, a metabolic response signature was observed involving decreased energy metabolism and reduced IGF-1 signaling, a major modulator of life span. We conclude that while the increased apoptotic response to endogenous DNA damage contributes to the accelerated aging phenotypes and the reduced cancer incidence observed in the Xpd(TTD) mice, the signature of reduced energy metabolism is likely to reflect a compensatory adjustment to limit the increased genotoxic stress in these mutants. These results support a general model for premature aging in DNA repair deficient mice based on cellular responses to DNA damage that impair normal tissue homeostasis.
Collapse
Affiliation(s)
- Jung Yoon Park
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Mi-Ook Cho
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Shanique Leonard
- Department of Physiology, Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Brent Calder
- Buck Institute for Age Research, Novato, California, United States of America
| | - I. Saira Mian
- Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Woo Ho Kim
- Department of Pathology, Seoul National University College of Medicine, Seoul, Korea
| | - Susan Wijnhoven
- National Institute of Public Health and the Environment, Laboratory of Toxicology, Pathology and Genetics, Bilthoven, the Netherlands
| | - Harry van Steeg
- National Institute of Public Health and the Environment, Laboratory of Toxicology, Pathology and Genetics, Bilthoven, the Netherlands
| | - James Mitchell
- MGC-Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | | | - Jan Hoeijmakers
- MGC-Department of Cell Biology and Genetics, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Pinchas Cohen
- Pediatric Endocrinology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jan Vijg
- Buck Institute for Age Research, Novato, California, United States of America
| | - Yousin Suh
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
| |
Collapse
|
12
|
Choksi KB, Roberts LJ, DeFord JH, Rabek JP, Papaconstantinou J. Lower levels of F2-isoprostanes in serum and livers of long-lived Ames dwarf mice. Biochem Biophys Res Commun 2007; 364:761-4. [PMID: 17964285 DOI: 10.1016/j.bbrc.2007.10.100] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 10/08/2007] [Indexed: 12/13/2022]
Abstract
F2-isoprostanes (IsoPs), lipid peroxidation products, are markers that quantitatively measure levels of oxidative stress. IsoP levels increase in tissues and serum of aging animals suggesting an increase in oxidative stress. This supports the Free Radical Theory of Aging, which proposes that elevated levels of reactive oxygen species (ROS) cause macromolecular damage, and is a factor in the age-associated decline in tissue function. Numerous studies have shown that the longevity of long-lived mutant mice correlates with their resistance to oxidative stress. However, although the Ames dwarf (DW) mice show resistance to oxidative stress, it has not been shown that these mice have inherently lower levels of ROS. Our results show that the serum and liver IsoP levels in DW mice are lower at all ages suggesting that the lower levels of endogenous ROS production in DW mice may be a factor in their resistance to oxidative stress and longevity.
Collapse
Affiliation(s)
- Kashyap B Choksi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-0643, USA
| | | | | | | | | |
Collapse
|
13
|
Swindell WR. Genotype-by-age interaction and identification of longevity-associated genes from microarray data. AGE (DORDRECHT, NETHERLANDS) 2007; 29:97-102. [PMID: 19424835 PMCID: PMC2267658 DOI: 10.1007/s11357-007-9033-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Accepted: 05/06/2007] [Indexed: 05/27/2023]
Abstract
Microarray-based comparisons of long-lived and normal mouse strains represent a promising approach for dissecting the basis of lifespan extension in higher organisms. Recently, Boylston et al. (2006) generated a genome-wide data set that allowed expression levels of Snell (Pit1 (dw/dw)) and Ames (Prop1 (df/df)) long-lived mice to be compared with age-matched control mice across different ages (6-24 months). Longevity-associated genes were identified as those genes exhibiting differential expression between long-lived and normal mice at every age examined. In this communication, an alternative approach to identifying longevity-associated genes is suggested and applied to the data sets considered by Boylston et al. (2006). Longevity-associated genes are defined as those exhibiting significant genotype-by-age interaction with respect to expression levels of long-lived and normal mice, and a total of 63 longevity-associated genes are identified. This approach may lend greater confidence to the inference that expression of identified genes specifically underlies aging differences between long-lived and normal genotypes.
Collapse
Affiliation(s)
- William R Swindell
- Department of Statistics and Probability, Michigan State University, A-413 Wells Hall, East Lansing, MI 48824, USA.
| |
Collapse
|