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Marola OJ, MacLean M, Cossette TL, Diemler CA, Hewes AA, Reagan AM, Skelly DA, Howell GR. Genetic context modulates aging and degeneration in the murine retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.16.589625. [PMID: 38659747 PMCID: PMC11042269 DOI: 10.1101/2024.04.16.589625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Background Age is the principal risk factor for neurodegeneration in both the retina and brain. The retina and brain share many biological properties; thus, insights into retinal aging and degeneration may shed light onto similar processes in the brain. Genetic makeup strongly influences susceptibility to age-related retinal disease. However, studies investigating retinal aging have not sufficiently accounted for genetic diversity. Therefore, examining molecular aging in the retina across different genetic backgrounds will enhance our understanding of human-relevant aging and degeneration in both the retina and brain-potentially improving therapeutic approaches to these debilitating conditions. Methods Transcriptomics and proteomics were employed to elucidate retinal aging signatures in nine genetically diverse mouse strains (C57BL/6J, 129S1/SvlmJ, NZO/HlLtJ, WSB/EiJ, CAST/EiJ, PWK/PhK, NOD/ShiLtJ, A/J, and BALB/cJ) across lifespan. These data predicted human disease-relevant changes in WSB and NZO strains. Accordingly, B6, WSB and NZO mice were subjected to human-relevant in vivo examinations at 4, 8, 12, and/or 18M, including: slit lamp, fundus imaging, optical coherence tomography, fluorescein angiography, and pattern/full-field electroretinography. Retinal morphology, vascular structure, and cell counts were assessed ex vivo. Results We identified common molecular aging signatures across the nine mouse strains, which included genes associated with photoreceptor function and immune activation. Genetic background strongly modulated these aging signatures. Analysis of cell type-specific marker genes predicted age-related loss of photoreceptors and retinal ganglion cells (RGCs) in WSB and NZO, respectively. Fundus exams revealed retinitis pigmentosa-relevant pigmentary abnormalities in WSB retinas and diabetic retinopathy (DR)-relevant cotton wool spots and exudates in NZO retinas. Profound photoreceptor dysfunction and loss were confirmed in WSB. Molecular analyses indicated changes in photoreceptor-specific proteins prior to loss, suggesting photoreceptor-intrinsic dysfunction in WSB. In addition, age-associated RGC dysfunction, loss, and concomitant microvascular dysfunction was observed in NZO mice. Proteomic analyses revealed an early reduction in protective antioxidant processes, which may underlie increased susceptibility to DR-relevant pathology in NZO. Conclusions Genetic context is a strong determinant of retinal aging, and our multi-omics resource can aid in understanding age-related diseases of the eye and brain. Our investigations identified and validated WSB and NZO mice as improved preclinical models relevant to common retinal neurodegenerative diseases.
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Affiliation(s)
| | | | | | - Cory A. Diemler
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
| | | | | | | | - Gareth R. Howell
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA
- Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME 04469, USA
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2
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Shi J, Gao S, Chen Z, Chen Z, Yun D, Wu X, Sun F. Absence of MerTK disrupts spermatogenesis in an age-dependent manner. Mol Cell Endocrinol 2023; 560:111815. [PMID: 36379275 DOI: 10.1016/j.mce.2022.111815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 11/15/2022]
Abstract
Spermatogenesis is a highly specialized cell differentiation process regulated by the testicular microenvironment. During the process of spermatogenesis, phagocytosis performs an essential role in male germ cell development, and its dysfunction in the testis can cause reproduction defects. MerTK, as a critical protein of phagocytosis, facilitates the removal of apoptotic substrates from the retina and ovaries through cooperation with several phagocytosis receptors. However, its role in mammalian spermatogenesis remains undefined. Here, we found that 30-week-old MerTK-/- male mice developed oligoasthenospermia due to abnormal spermatogenesis. These mice showed damaged seminiferous tubule structure, as well as altered spermatogonia proliferation and differentiation. We also found that Sertoli cells from MerTK-/- mice had decreased phagocytic activity on apoptotic germ cells in vitro. Moreover, a transcriptomic analysis demonstrated that the pivotal genes involved in spermatid differentiation and development changed expression. These results indicate that MerTK is crucial for spermatogenesis, as it regulates the crosstalk between germ cells and Sertoli cells. This provides us insight into the molecular mechanism of MerTK on spermatogenesis and its implications for the diagnosis and treatment of human male infertility.
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Affiliation(s)
- Jie Shi
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China
| | - Sheng Gao
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China
| | - Zhengru Chen
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China
| | - Zifeng Chen
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China
| | - Damin Yun
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China
| | - Xiaolong Wu
- Department of Urology & Andrology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310016, China
| | - Fei Sun
- Institute of Reproductive Medicine, Medical School of Nantong University, Nantong, 226001, China.
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3
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Avchaciov K, Antoch MP, Andrianova EL, Tarkhov AE, Menshikov LI, Burmistrova O, Gudkov AV, Fedichev PO. Unsupervised learning of aging principles from longitudinal data. Nat Commun 2022; 13:6529. [PMID: 36319638 PMCID: PMC9626636 DOI: 10.1038/s41467-022-34051-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/06/2022] [Indexed: 11/07/2022] Open
Abstract
Age is the leading risk factor for prevalent diseases and death. However, the relation between age-related physiological changes and lifespan is poorly understood. We combined analytical and machine learning tools to describe the aging process in large sets of longitudinal measurements. Assuming that aging results from a dynamic instability of the organism state, we designed a deep artificial neural network, including auto-encoder and auto-regression (AR) components. The AR model tied the dynamics of physiological state with the stochastic evolution of a single variable, the "dynamic frailty indicator" (dFI). In a subset of blood tests from the Mouse Phenome Database, dFI increased exponentially and predicted the remaining lifespan. The observation of the limiting dFI was consistent with the late-life mortality deceleration. dFI changed along with hallmarks of aging, including frailty index, molecular markers of inflammation, senescent cell accumulation, and responded to life-shortening (high-fat diet) and life-extending (rapamycin) treatments.
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Affiliation(s)
| | - Marina P Antoch
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
| | | | | | | | | | - Andrei V Gudkov
- Genome Protection, Inc., Buffalo, NY, USA
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA
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4
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Ward JM, Vogel P, Sundberg JP. Brain and spinal cord lesions in 28 inbred strains of aging mice. Vet Pathol 2022; 59:1047-1055. [PMID: 36062914 DOI: 10.1177/03009858221120009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Brain and spinal cord histopathology findings in male and female 20-month-old mice in a large-scale aging study of 28 inbred Jackson Laboratory mouse strains from 7 genetic families are described. Brain sections from selected strains at 12 and 24 months of age or older were also reviewed. Common lesions include axonal dystrophy in the gracile and/or cuneate nucleus in the sensory tract of the dorsal medulla and in the spinal cord in all strains. Hirano-like bodies were seen in 24/28 strains, and mineralization was observed in the thalamus of 9/28 strains. Less common lesions were also seen in the cerebellum, cerebral cortex, and other brain areas. No brain or spinal cord tumors were found. Evidence of an impairment of the ubiquitin-proteasome system (UPS) and/or suspected autophagy was manifested as medullary axonal dystrophy with intra-axonal granular eosinophilic bodies and LC3B immunohistochemistry in most strains. RIIIS/J, the most severely affected strain, showed moderate axonal dystrophy at 12 months, which progressed to severe lesions at 20 months. Comparative pathology in various species is discussed.
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Affiliation(s)
- Jerrold M Ward
- The Jackson Laboratory, Bar Harbor, ME.,Global Vet Pathology, Montgomery Village, MD
| | - Peter Vogel
- St. Jude Children's Research Hospital, Memphis, TN
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5
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Dunnick JK, Pandiri AR, Shockley KR, Herbert R, Mav D, Phadke D, Shah RR, Merrick BA. Single nucleotide polymorphism patterns associated with a cancer resistant phenotype. Exp Mol Pathol 2022; 128:104812. [PMID: 35872013 PMCID: PMC10463559 DOI: 10.1016/j.yexmp.2022.104812] [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: 04/27/2022] [Revised: 06/14/2022] [Accepted: 07/16/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND AIMS In this study ten mouse strains representing ~90% of genetic diversity in laboratory mice (B6C3F1/J, C57BL/6J, C3H/HeJ, A/J, NOD.B1oSnH2/J, NZO/HILtJ, 129S1/SvImJ, WSB/EiJ, PWK/PhJ, CAST/EiJ) were examined to identify the mouse strain with the lowest incidence of cancer. The unique single polymorphisms (SNPs) associated with this low cancer incidence are reported. METHODS Evaluations of cancer incidence in the 10 mouse strains were based on gross and microscopic diagnosis of tumors. Single nucleotide polymorphisms (SNPs) in the coding regions of the genome were derived from the respective mouse strains located in the Sanger mouse sequencing database and the B6C3F1/N genome from the National Toxicology Program (NTP). RESULTS The WSB strain had an overall lower incidence of both benign and malignant tumors compared to the other mouse strains. At 2 years, the incidence of total malignant tumors (Poly-3 incidence rate) ranged from 2% (WSB) to 92% (C3H) in males, and 14% (WSB) to 93% (NZO) in females, and the total incidence of benign and malignant tumor incidence ranged from 13% (WSB) to 99% (C3H) in males and 25% (WSB) to 96% (NOD) in females. Single nucleotide polymorphism (SNP) patterns were examined in the following strains: B6C3F1/N, C57BL/6J, C3H/HeJ, 129S1/SvImJ, A/J, NZO/HILtJ, CAST/EiJ, PWK/PhJ, and WSB/EiJ. We identified 7519 SNPs (involving 5751 Ensembl transcripts of 3453 Ensembl Genes) that resulted in a unique amino acid change in the coding region of the WSB strain. CONCLUSIONS The inherited genetic patterns in the WSB cancer-resistant mouse strain occurred in genes involved in multiple cell functions including mitochondria, metabolic, immune, and membrane-related cell functions. The unique SNP patterns in a cancer resistant mouse strain provides insights for understanding and developing strategies for cancer prevention.
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Affiliation(s)
- June K Dunnick
- Systemic Toxicology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA.
| | - Arun R Pandiri
- Comparative and Molecular Pathogenesis Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Keith R Shockley
- Biostatistics and Computational Biology Branch, Division of Intramural Research, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Ronald Herbert
- Comparative and Molecular Pathogenesis Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Deepak Mav
- Sciome, LLC, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Dhiral Phadke
- Sciome, LLC, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - Ruchir R Shah
- Sciome, LLC, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | - B Alex Merrick
- Mechanistic Toxicology Branch, National Institute of Environmental Health Sciences, Division of the National Toxicology Program, Research Triangle Park, NC 27709, USA
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6
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Wolf AM. Rodent diet aids and the fallacy of caloric restriction. Mech Ageing Dev 2021; 200:111584. [PMID: 34673082 DOI: 10.1016/j.mad.2021.111584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 12/14/2022]
Abstract
Understanding the molecular mechanisms of normal aging is a prerequisite to significantly improving human health span. Caloric restriction (CR) can delay aging and has served as a yardstick to evaluate interventions extending life span. However, mice given unlimited access to food suffer severe obesity. Health gains from CR depend on control mice being sufficiently overweight and less obese mouse strains benefit far less from CR. Pharmacologic interventions that increase life span, including resveratrol, rapamycin, nicotinamide mononucleotide and metformin, also reduce body weight. In primates, CR does not delay aging unless the control group is eating enough to suffer from obesity-related disease. Human survival is optimal at a body mass index achievable without CR, and the above interventions are merely diet aids that shouldn't slow aging in healthy weight individuals. CR in humans of optimal weight can safely be declared useless, since there is overwhelming evidence that hunger, underweight and starvation reduce fitness, survival, and quality of life. Against an obese control, CR does, however, truly delay aging through a mechanism laid out in the following tumor suppression theory of aging.
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Affiliation(s)
- Alexander M Wolf
- Laboratory for Morphological and Biomolecular Imaging, Faculty of Medicine, Nippon Medical School, Japan.
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7
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Abstract
Trauma, burn injury, sepsis, and ischemia lead to acute and chronic loss of skeletal muscle mass and function. Healthy muscle is essential for eating, posture, respiration, reproduction, and mobility, as well as for appropriate function of the senses including taste, vision, and hearing. Beyond providing support and contraction, skeletal muscle also exerts essential roles in temperature regulation, metabolism, and overall health. As the primary reservoir for amino acids, skeletal muscle regulates whole-body protein and glucose metabolism by providing substrate for protein synthesis and supporting hepatic gluconeogenesis during illness and starvation. Overall, greater muscle mass is linked to greater insulin sensitivity and glucose disposal, strength, power, and longevity. In contrast, low muscle mass correlates with dysmetabolism, dysmobility, and poor survival. Muscle mass is highly plastic, appropriate to its role as reservoir, and subject to striking genetic control. Defining mechanisms of muscle growth regulation holds significant promise to find interventions that promote health and diminish morbidity and mortality after trauma, sepsis, inflammation, and other systemic insults. In this invited review, we summarize techniques and methods to assess and manipulate muscle size and muscle mass in experimental systems, including cell culture and rodent models. These approaches have utility for studies of myopenia, sarcopenia, cachexia, and acute muscle growth or atrophy in the setting of health or injury.
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8
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Yuan R, Musters CJM, Zhu Y, Evans TR, Sun Y, Chesler EJ, Peters LL, Harrison DE, Bartke A. Genetic differences and longevity-related phenotypes influence lifespan and lifespan variation in a sex-specific manner in mice. Aging Cell 2020; 19:e13263. [PMID: 33105070 PMCID: PMC7681063 DOI: 10.1111/acel.13263] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/29/2020] [Accepted: 09/15/2020] [Indexed: 12/20/2022] Open
Abstract
Epidemiological studies of human longevity found two interesting features, robust advantage of female lifespan and consistent reduction of lifespan variation. To help understand the genetic aspects of these phenomena, the current study examined sex differences and variation of longevity using previously published mouse data sets including data on lifespan, age of puberty, and circulating insulin-like growth factor 1 (IGF1) levels in 31 inbred strains, data from colonies of nuclear-receptor-interacting protein 1 (Nrip1) knockout mice, and a congenic strain, B6.C3H-Igf1. Looking at the overall data for all inbred strains, the results show no significant difference in lifespan and lifespan variation between sexes; however, considerable differences were found among and within strains. Across strains, lifespan variations of female and male mice are significantly correlated. Strikingly, between sexes, IGF1 levels correlate with the lifespan variation and maximum lifespan in different directions. Female mice with low IGF1 levels have higher variation and extended maximum lifespan. The opposite is detected in males. Compared to domesticated inbred strains, wild-derived inbred strains have elevated lifespan variation due to increased early deaths in both sexes and extended maximum lifespan in female mice. Intriguingly, the sex differences in survival curves of inbred strains negatively associated with age of female puberty, which is significantly accelerated in domesticated inbred strains compared to wild-derived strains. In conclusion, this study suggests that genetic factors are involved in the regulation of sexual disparities in lifespan and lifespan variation, and dissecting the mouse genome may provide novel insight into the underlying genetic mechanisms.
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Affiliation(s)
- Rong Yuan
- Department of Internal MedicineGeriatrics ResearchSouthern Illinois University School of MedicineSpringfieldILUSA
| | - C. J. M. Musters
- Institute of Environmental SciencesLeiden UniversityLeidenThe Netherlands
| | - Yun Zhu
- Department of Internal MedicineGeriatrics ResearchSouthern Illinois University School of MedicineSpringfieldILUSA
- Department of Molecular Biology, Microbiology and BiochemistrySouthern Illinois University School of MedicineSpringfieldILUSA
| | - Tracy R. Evans
- Department of NeurologySouthern Illinois University School of MedicineSpringfieldILUSA
| | - Yujie Sun
- Department of Internal MedicineGeriatrics ResearchSouthern Illinois University School of MedicineSpringfieldILUSA
- Institute of DermatologyChinese Academy of Medical Sciences and Peking Union Medical CollegeNanjingChina
| | - Elissa J. Chesler
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of AgingBar HarborMEUSA
| | - Luanne L. Peters
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of AgingBar HarborMEUSA
| | - David E. Harrison
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of AgingBar HarborMEUSA
| | - Andrzej Bartke
- Department of Internal MedicineGeriatrics ResearchSouthern Illinois University School of MedicineSpringfieldILUSA
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9
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Bellantuono I, de Cabo R, Ehninger D, Di Germanio C, Lawrie A, Miller J, Mitchell SJ, Navas-Enamorado I, Potter PK, Tchkonia T, Trejo JL, Lamming DW. A toolbox for the longitudinal assessment of healthspan in aging mice. Nat Protoc 2020; 15:540-574. [PMID: 31915391 PMCID: PMC7002283 DOI: 10.1038/s41596-019-0256-1] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 10/10/2019] [Indexed: 12/11/2022]
Abstract
The number of people aged over 65 is expected to double in the next 30 years. For many, living longer will mean spending more years with the burdens of chronic diseases such as Alzheimer's disease, cardiovascular disease, and diabetes. Although researchers have made rapid progress in developing geroprotective interventions that target mechanisms of aging and delay or prevent the onset of multiple concurrent age-related diseases, a lack of standardized techniques to assess healthspan in preclinical murine studies has resulted in reduced reproducibility and slow progress. To overcome this, major centers in Europe and the United States skilled in healthspan analysis came together to agree on a toolbox of techniques that can be used to consistently assess the healthspan of mice. Here, we describe the agreed toolbox, which contains protocols for echocardiography, novel object recognition, grip strength, rotarod, glucose tolerance test (GTT) and insulin tolerance test (ITT), body composition, and energy expenditure. The protocols can be performed longitudinally in the same mouse over a period of 4-6 weeks to test how candidate geroprotectors affect cardiac, cognitive, neuromuscular, and metabolic health.
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Affiliation(s)
- I Bellantuono
- Department of Oncology and Metabolism, Healthy Lifespan Institute and MRC-Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing, University of Sheffield, Sheffield, UK.
| | - R de Cabo
- Translational Gerontology Branch, National Institutes of Health, Baltimore, MD, USA
| | - D Ehninger
- German Center for Neurodegenerative Diseases (DZNE), Venusberg Campus 1, Bonn, Germany
| | - C Di Germanio
- Translational Gerontology Branch, National Institutes of Health, Baltimore, MD, USA
| | - A Lawrie
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - J Miller
- Robert and Arlene KogodCenter on Aging, Mayo Clinic, Rochester, MN, USA
| | - S J Mitchell
- Department of Molecular Medicine, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - I Navas-Enamorado
- Translational Gerontology Branch, National Institutes of Health, Baltimore, MD, USA
| | - P K Potter
- Department of Biological and Life Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxfordshire, UK
| | - T Tchkonia
- Robert and Arlene KogodCenter on Aging, Mayo Clinic, Rochester, MN, USA
| | - J L Trejo
- Department of Translational Neuroscience, Cajal Institute (CSIC), Madrid, Spain
| | - D W Lamming
- William S. Middleton Memorial Veterans Hospital, Madison, WI, USA.
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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10
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Kruempel JC, Howington MB, Leiser SF. Computational tools for geroscience. TRANSLATIONAL MEDICINE OF AGING 2019; 3:132-143. [PMID: 33241167 PMCID: PMC7685266 DOI: 10.1016/j.tma.2019.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The rapid progress of the past three decades has led the geroscience field near a point where human interventions in aging are plausible. Advances across scientific areas, such as high throughput "-omics" approaches, have led to an exponentially increasing quantity of data available for biogerontologists. To best translate the lifespan and healthspan extending interventions discovered by basic scientists into preventative medicine, it is imperative that the current data are comprehensively utilized to generate testable hypotheses about translational interventions. Building a translational pipeline for geroscience will require both systematic efforts to identify interventions that extend healthspan across taxa and diagnostics that can identify patients who may benefit from interventions prior to the onset of an age-related morbidity. Databases and computational tools that organize and analyze both the wealth of information available on basic biogerontology research and clinical data on aging populations will be critical in developing such a pipeline. Here, we review the current landscape of databases and computational resources available for translational aging research. We discuss key platforms and tools available for aging research, with a focus on how each tool can be used in concert with hypothesis driven experiments to move closer to human interventions in aging.
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Affiliation(s)
- Joseph C.P. Kruempel
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Marshall B. Howington
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Scott F. Leiser
- Molecular & Integrative Physiology Department, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
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11
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McCorrison J, Girke T, Goetz LH, Miller RA, Schork NJ. Genetic Support for Longevity-Enhancing Drug Targets: Issues, Preliminary Data, and Future Directions. J Gerontol A Biol Sci Med Sci 2019; 74:S61-S71. [PMID: 31724058 PMCID: PMC7330475 DOI: 10.1093/gerona/glz206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Indexed: 12/16/2022] Open
Abstract
Interventions meant to promote longevity and healthy aging have often been designed or observed to modulate very specific gene or protein targets. If there are naturally occurring genetic variants in such a target that affect longevity as well as the molecular function of that target (eg, the variants influence the expression of the target, acting as "expression quantitative trait loci" or "eQTLs"), this could support a causal relationship between the pharmacologic modulation of the target and longevity and thereby validate the target at some level. We considered the gene targets of many pharmacologic interventions hypothesized to enhance human longevity and explored how many variants there are in those targets that affect gene function (eg, as expression quantitative trait loci). We also determined whether variants in genes associated with longevity-related phenotypes affect gene function or are in linkage disequilibrium with variants that do, and whether pharmacologic studies point to compounds exhibiting activity against those genes. Our results are somewhat ambiguous, suggesting that integrating genetic association study results with functional genomic and pharmacologic studies is necessary to shed light on genetically mediated targets for longevity-enhancing drugs. Such integration will require more sophisticated data sets, phenotypic definitions, and bioinformatics approaches to be useful.
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Affiliation(s)
- Jamison McCorrison
- Graduate Program in Bioinformatics and Systems Biology, University of California–San Diego, Phoenix, Arizona
| | - Thomas Girke
- Institute for Integrative Genome Biology, University of California, Riverside, Phoenix, Arizona
| | - Laura H Goetz
- Department of Quantitative Medicine and Systems Biology, The Translational Genomics Research Institute (TGen), Phoenix, Arizona
- Department of Medical Oncology, City of Hope National Medical Center, Duarte, California
| | - Richard A Miller
- Department of Pathology, Ann Arbor
- Glenn Center for the Biology of Aging, University of Michigan, Ann Arbor
| | - Nicholas J Schork
- Department of Quantitative Medicine and Systems Biology, The Translational Genomics Research Institute (TGen), Phoenix, Arizona
- Department of Population Sciences, City of Hope National Medical Center, Duarte, California
- Department of Psychiatry, University of California–San Diego
- Department of Family Medicine and Public Health, University of California–San Diego
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12
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Cooper TK, Silva KA, Kennedy VE, Alghamdi S, Hoehndorf R, Sundberg BA, Schofield PN, Sundberg JP. Hyaline Arteriolosclerosis in 30 Strains of Aged Inbred Mice. Vet Pathol 2019; 56:799-806. [PMID: 31060453 DOI: 10.1177/0300985819844822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
During a screen for vascular phenotypes in aged laboratory mice, a unique discrete phenotype of hyaline arteriolosclerosis of the intertubular arteries and arterioles of the testes was identified in several inbred strains. Lesions were limited to the testes and did not occur as part of any renal, systemic, or pulmonary arteriopathy or vasculitis phenotype. There was no evidence of systemic or pulmonary hypertension, and lesions did not occur in ovaries of females. Frequency was highest in males of the SM/J (27/30, 90%) and WSB/EiJ (19/26, 73%) strains, aged 383 to 847 days. Lesions were sporadically present in males from several other inbred strains at a much lower (<20%) frequency. The risk of testicular hyaline arteriolosclerosis is at least partially underpinned by a genetic predisposition that is not associated with other vascular lesions (including vasculitis), separating out the etiology of this form and site of arteriolosclerosis from other related conditions that often co-occur in other strains of mice and in humans. Because of their genetic uniformity and controlled dietary and environmental conditions, mice are an excellent model to dissect the pathogenesis of human disease conditions. In this study, a discrete genetically driven phenotype of testicular hyaline arteriolosclerosis in aging mice was identified. These observations open the possibility of identifying the underlying genetic variant(s) associated with the predisposition and therefore allowing future interrogation of the pathogenesis of this condition.
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Affiliation(s)
- Timothy K Cooper
- 1 Department of Comparative Medicine, Penn State Milton S. Hershey Medical Center, Hershey, PA, USA.,2 Department of Pathology, Penn State Milton S. Hershey Medical Center, Hershey, PA, USA
| | | | | | - Sarah Alghamdi
- 4 Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | - Robert Hoehndorf
- 4 Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
| | | | - Paul N Schofield
- 3 The Jackson Laboratory, Bar Harbor, ME, USA.,5 Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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13
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Mesner LD, Calabrese GM, Al-Barghouthi B, Gatti DM, Sundberg JP, Churchill GA, Godfrey DA, Ackert-Bicknell CL, Farber CR. Mouse genome-wide association and systems genetics identifies Lhfp as a regulator of bone mass. PLoS Genet 2019; 15:e1008123. [PMID: 31042701 PMCID: PMC6513102 DOI: 10.1371/journal.pgen.1008123] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 05/13/2019] [Accepted: 04/03/2019] [Indexed: 11/19/2022] Open
Abstract
Bone mineral density (BMD) is a strong predictor of osteoporotic fracture. It is also one of the most heritable disease-associated quantitative traits. As a result, there has been considerable effort focused on dissecting its genetic basis. Here, we performed a genome-wide association study (GWAS) in a panel of inbred strains to identify associations influencing BMD. This analysis identified a significant (P = 3.1 x 10−12) BMD locus on Chromosome 3@52.5 Mbp that replicated in two separate inbred strain panels and overlapped a BMD quantitative trait locus (QTL) previously identified in a F2 intercross. The association mapped to a 300 Kbp region containing four genes; Gm2447, Gm20750, Cog6, and Lhfp. Further analysis found that Lipoma HMGIC Fusion Partner (Lhfp) was highly expressed in bone and osteoblasts. Furthermore, its expression was regulated by a local expression QTL (eQTL), which overlapped the BMD association. A co-expression network analysis revealed that Lhfp was strongly connected to genes involved in osteoblast differentiation. To directly evaluate its role in bone, Lhfp deficient mice (Lhfp-/-) were created using CRISPR/Cas9. Consistent with genetic and network predictions, bone marrow stromal cells (BMSCs) from Lhfp-/- mice displayed increased osteogenic differentiation. Lhfp-/- mice also had elevated BMD due to increased cortical bone mass. Lastly, we identified SNPs in human LHFP that were associated (P = 1.2 x 10−5) with heel BMD. In conclusion, we used GWAS and systems genetics to identify Lhfp as a regulator of osteoblast activity and bone mass. Osteoporosis is a common, chronic disease characterized by low bone mineral density (BMD) that puts millions of Americans at high risk of fracture. Variation in BMD in the general population is, in large part, determined by genetic factors. To identify novel genes influencing BMD, we performed a genome-wide association study in a panel of inbred mouse strains. We identified a locus on Chromosome 3 strongly associated with BMD. Using a combination of systems genetics approaches, we connected the expression of the Lhfp gene with BMD-associated genetic variants and predicted it influenced BMD by altering the activity of bone-forming osteoblasts. Using mice deficient in Lhfp, we demonstrated that Lhfp negatively regulates bone formation and BMD. These data suggest that inhibiting Lhfp may represent a novel therapeutic strategy to increase BMD and decrease the risk of fracture.
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Affiliation(s)
- Larry D. Mesner
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, United States of America
- Department of Public Health Sciences, University of Virginia, Charlottesville, VA, United States of America
| | - Gina M. Calabrese
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, United States of America
| | - Basel Al-Barghouthi
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, United States of America
- Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, United States of America
| | - Daniel M. Gatti
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - John P. Sundberg
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | | | - Dana. A. Godfrey
- Center for Musculoskeletal Research, University of Rochester, Rochester, NY, United States of America
| | - Cheryl L. Ackert-Bicknell
- Center for Musculoskeletal Research, University of Rochester, Rochester, NY, United States of America
| | - Charles R. Farber
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, United States of America
- Department of Public Health Sciences, University of Virginia, Charlottesville, VA, United States of America
- Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, United States of America
- * E-mail:
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14
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Csiszar A, Balasubramanian P, Tarantini S, Yabluchanskiy A, Zhang XA, Springo Z, Benbrook D, Sonntag WE, Ungvari Z. Chemically induced carcinogenesis in rodent models of aging: assessing organismal resilience to genotoxic stressors in geroscience research. GeroScience 2019; 41:209-227. [PMID: 31037472 DOI: 10.1007/s11357-019-00064-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 04/04/2019] [Indexed: 02/07/2023] Open
Abstract
There is significant overlap between the cellular and molecular mechanisms of aging and pathways contributing to carcinogenesis, including the role of genome maintenance pathways. In the field of geroscience analysis of novel genetic mouse models with either a shortened, or an extended, lifespan provides a unique opportunity to evaluate the synergistic roles of longevity assurance pathways in cancer resistance and regulation of lifespan and to develop novel targets for interventions that both delay aging and prevent carcinogenesis. There is a growing need for robust assays to assess the susceptibility of cancer in these models. The present review focuses on a well-characterized method frequently used in cancer research, which can be adapted to study resilience to genotoxic stress and susceptibility to genotoxic stress-induced carcinogenesis in geroscience research namely, chemical carcinogenesis induced by treatment with 7,12-dimethylbenz(a)anthracene (DMBA). Recent progress in understanding how longer-living mice may achieve resistance to chemical carcinogenesis and how these pathways are modulated by anti-aging interventions is reviewed. Strain-specific differences in sensitivity to DMBA-induced carcinogenesis are also explored and contrasted with mouse lifespan. The clinical relevance of inhibition of DMBA-induced carcinogenesis for the pathogenesis of mammary adenocarcinomas in older human subjects is discussed. Finally, the potential role of insulin-like growth factor-1 (IGF-1) in the regulation of pathways responsible for cellular resilience to DMBA-induced mutagenesis is discussed.
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Affiliation(s)
- Anna Csiszar
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.,Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Priya Balasubramanian
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Stefano Tarantini
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Andriy Yabluchanskiy
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.,Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Xin A Zhang
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zsolt Springo
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.,Theoretical Medicine Doctoral School, University of Szeged, Szeged, Hungary
| | - Doris Benbrook
- Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Department of Obstetrics and Gynecology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - William E Sonntag
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.,Department of Biochemistry, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Zoltan Ungvari
- Department of Geriatric Medicine Vascular Cognitive Impairment and Neurodegeneration Program, Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA. .,Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Theoretical Medicine Doctoral School, University of Szeged, Szeged, Hungary. .,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary. .,Department of Public Health, Semmelweis University, Budapest, Hungary.
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15
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Kumar Chaudhary M, Rizvi SI. Invertebrate and vertebrate models in aging research. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2019; 163:114-121. [PMID: 30837761 DOI: 10.5507/bp.2019.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 02/06/2019] [Indexed: 12/27/2022] Open
Abstract
Therapeutic interventions that can delay age associated diseases and ensure a longer health-span is a major goal of aging research. Consequent to understanding that aging is a modifiable trait, a large number of studies are currently being undertaken to elucidate the mechanism(s) of the aging process. Research on human aging and longevity is difficult, due to longer time frame, ethical concerns and environmental variables. Most of the present day understanding about the aging process comes through studies conducted on model organisms. These provide suitable platforms for understanding underlying mechanism(s) which control aging and have led to major discoveries that emphasize the evolutionarily conserved molecular pathways as key players that respond to extra and intracellular signals. This is a review of various invertebrate and vertebrate models including yeast, Drosophila, C. elegans, rodents, naked mole rat, and birds, currently used in aging research with emphasis on how well they can mimic aging in higher animals and humans.
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Affiliation(s)
| | - Syed Ibrahim Rizvi
- Department of Biochemistry, University of Allahabad, Allahabad-211002, India
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16
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Abstract
The types of changes in physical appearance and behavior that occur in elderly people similarly develop in elderly animals. Signs and symptoms that might cause concern in younger people or mice may be normal in their elderly but generally healthy counterparts. Although numerous scoring methods have been developed to assess rodent health, these systems were often designed for young adults used in specific types of research, such as cancer or neurologic studies, and therefore may be suboptimal for assessing aging rodents. Approaches known as frailty assessments provide a global evaluation of the health of aged mice, rats, and people, and mouse frailty scores correlate well with the likelihood of death. Complementing frailty assessment, prediction of imminent death in aged mice can often be accomplished by focusing on 2 objective parameters-body weight and temperature. Before they die, many (but not all) mice develop marked reductions in body weight and temperature, thus providing signs that close monitoring, intervention, or preemptive euthanasia may be necessary. Timely preemptive euthanasia allows antemortem collection of data and samples that would be lost if spontaneous death occurred; preemptive euthanasia also limits terminal suffering. These approaches to monitoring declining health and predicting death in elderly research mice can aid in establishing and implementing timely interventions that both benefit the research and reduce antemortem suffering.
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Affiliation(s)
- Linda A Toth
- Emeritus Faculty, Southern Illinois University School of Medicine, Springfield, Illinois, USA.
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17
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Hook M, Roy S, Williams EG, Bou Sleiman M, Mozhui K, Nelson JF, Lu L, Auwerx J, Williams RW. Genetic cartography of longevity in humans and mice: Current landscape and horizons. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2718-2732. [PMID: 29410319 PMCID: PMC6066442 DOI: 10.1016/j.bbadis.2018.01.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/24/2018] [Accepted: 01/28/2018] [Indexed: 12/14/2022]
Abstract
Aging is a complex and highly variable process. Heritability of longevity among humans and other species is low, and this finding has given rise to the idea that it may be futile to search for DNA variants that modulate aging. We argue that the problem in mapping longevity genes is mainly one of low power and the genetic and environmental complexity of aging. In this review we highlight progress made in mapping genes and molecular networks associated with longevity, paying special attention to work in mice and humans. We summarize 40 years of linkage studies using murine cohorts and 15 years of studies in human populations that have exploited candidate gene and genome-wide association methods. A small but growing number of gene variants contribute to known longevity mechanisms, but a much larger set have unknown functions. We outline these and other challenges and suggest some possible solutions, including more intense collaboration between research communities that use model organisms and human cohorts. Once hundreds of gene variants have been linked to differences in longevity in mammals, it will become feasible to systematically explore gene-by-environmental interactions, dissect mechanisms with more assurance, and evaluate the roles of epistasis and epigenetics in aging. A deeper understanding of complex networks-genetic, cellular, physiological, and social-should position us well to improve healthspan.
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Affiliation(s)
- Michael Hook
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Suheeta Roy
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Evan G Williams
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, Zurich CH-8093, Switzerland
| | - Maroun Bou Sleiman
- Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Khyobeni Mozhui
- Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - James F Nelson
- Department of Cellular and Integrative Physiology and Barshop Institute for Longevity and Aging Studies, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Lu Lu
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Johan Auwerx
- Interfaculty Institute of Bioengineering, Laboratory of Integrative and Systems Physiology, Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
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18
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Genomic and transcriptomic comparison of allergen and silver nanoparticle-induced mast cell degranulation reveals novel non-immunoglobulin E mediated mechanisms. PLoS One 2018; 13:e0193499. [PMID: 29566008 PMCID: PMC5863960 DOI: 10.1371/journal.pone.0193499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 02/12/2018] [Indexed: 02/07/2023] Open
Abstract
Mast cells represent a crucial cell type in host defense; however, maladaptive responses are contributing factors in the pathogenesis of allergic diseases. Previous work in our laboratory has shown that exposure to silver nanoparticles (AgNPs) results in mast cell degranulation via a non-immunoglobulin E (IgE) mechanism. In this study, we utilized a systems biology approach to identify novel genetic factors playing a role in AgNP-induced mast cell degranulation compared to the classical activation by antigen-mediated FcεRI crosslinking. Mast cell degranulation was assessed in bone marrow-derived mast cells isolated from 23 strains of mice following exposure to AgNPs or FcεRI crosslinking with dinitrophenyl (DNP). Utilizing strain-dependent mast cell degranulation, an association mapping study identified 3 chromosomal regions that were significantly associated with mast cell degranulation by AgNP and one non-overlapping region associated with DNP-mediated degranulation. Two of the AgNP-associated regions correspond to genes previously reported to be associated with allergic disorders (Trac2 on chromosome 1 and Traf6 on chromosome 2) and an uncharacterized gene identified on chromosome 1 (Fam126b). In conjunction, RNA-sequencing performed on mast cells from the high and low responder strains revealed 3754 and 34 differentially expressed genes that were unique to DNP and AgNP exposures, respectively. Select candidate genes include Ptger4, a gene encoding a G-protein coupled receptor in addition to a multifunctional adaptor protein, Txnip, that may be driving mast cell degranulation by AgNP. Taken together, we identified novel genes that have not been previously shown to play a role in nanoparticle-mediated mast cell activation. With further functional evaluation in the future, these genes may be potential therapeutic targets in the treatment of non-IgE mediated mast cell-linked disorders.
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19
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An JY, Darveau R, Kaeberlein M. Oral health in geroscience: animal models and the aging oral cavity. GeroScience 2018; 40:1-10. [PMID: 29282653 PMCID: PMC5832657 DOI: 10.1007/s11357-017-0004-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 12/14/2017] [Indexed: 12/31/2022] Open
Abstract
Age is the single greatest risk factor for many diseases, including oral diseases. Despite this, a majority of preclinical oral health research has not adequately considered the importance of aging in research aimed at the mechanistic understanding of oral disease. Here, we have attempted to provide insights from animal studies in the geroscience field and apply them in the context of oral health research. In particular, we discuss the relationship between the biology of aging and mechanisms of oral disease. We also present a framework for defining and utilizing age-appropriate rodents and present experimental design considerations, such as the number of age-points used and the importance of genetic background. While focused primarily on rodent models, alternative animal models that may be particularly useful for studies of oral health during aging, such as companion dogs and marmoset monkeys, are also discussed. We hope that such information will aid in the design of future preclinical studies of geriatric dental health, thus allowing more reliability for translation of such studies to age-associated oral disease in people.
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Affiliation(s)
- Jonathan Y An
- Department of Oral Health Sciences, University of Washington School of Dentistry, Seattle, WA, 98195, USA
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, 98195, USA
| | - Richard Darveau
- Department of Periodontics, University of Washington School of Dentistry, Seattle, WA, 98195, USA
| | - Matt Kaeberlein
- Department of Oral Health Sciences, University of Washington School of Dentistry, Seattle, WA, 98195, USA.
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, 98195, USA.
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20
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Kafkafi N, Agassi J, Chesler EJ, Crabbe JC, Crusio WE, Eilam D, Gerlai R, Golani I, Gomez-Marin A, Heller R, Iraqi F, Jaljuli I, Karp NA, Morgan H, Nicholson G, Pfaff DW, Richter SH, Stark PB, Stiedl O, Stodden V, Tarantino LM, Tucci V, Valdar W, Williams RW, Würbel H, Benjamini Y. Reproducibility and replicability of rodent phenotyping in preclinical studies. Neurosci Biobehav Rev 2018; 87:218-232. [PMID: 29357292 PMCID: PMC6071910 DOI: 10.1016/j.neubiorev.2018.01.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/13/2017] [Accepted: 01/11/2018] [Indexed: 12/15/2022]
Abstract
The scientific community is increasingly concerned with the proportion of
published “discoveries” that are not replicated in subsequent
studies. The field of rodent behavioral phenotyping was one of the first to
raise this concern, and to relate it to other methodological issues: the complex
interaction between genotype and environment; the definitions of behavioral
constructs; and the use of laboratory mice and rats as model species for
investigating human health and disease mechanisms. In January 2015, researchers
from various disciplines gathered at Tel Aviv University to discuss these
issues. The general consensus was that the issue is prevalent and of concern,
and should be addressed at the statistical, methodological and policy levels,
but is not so severe as to call into question the validity and the usefulness of
model organisms as a whole. Well-organized community efforts, coupled with
improved data and metadata sharing, have a key role in identifying specific
problems and promoting effective solutions. Replicability is closely related to
validity, may affect generalizability and translation of findings, and has
important ethical implications.
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Affiliation(s)
| | | | | | - John C Crabbe
- Oregon Health & Science University, and VA Portland Health Care System, United States
| | | | | | | | | | | | | | | | | | - Natasha A Karp
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | | | | | | | | | | | | | | | | | - William Valdar
- University of North Carolina at Chapel Hill, United States
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21
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Lee MB, Kaeberlein M. Translational Geroscience: From invertebrate models to companion animal and human interventions. TRANSLATIONAL MEDICINE OF AGING 2018; 2:15-29. [PMID: 32368707 PMCID: PMC7198054 DOI: 10.1016/j.tma.2018.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Translational geroscience is an interdisciplinary field descended from basic gerontology that seeks to identify, validate, and clinically apply interventions to maximize healthy, disease-free lifespan. In this review, we describe a research pipeline for the identification and validation of lifespan extending interventions. Beginning in invertebrate model systems, interventions are discovered and then characterized using other invertebrate model systems (evolutionary translation), models of genetic diversity, and disease models. Vertebrate model systems, particularly mice, can then be utilized to validate interventions in mammalian systems. Collaborative, multi-site efforts, like the Interventions Testing Program (ITP), provide a key resource to assess intervention robustness in genetically diverse mice. Mouse disease models provide a tool to understand the broader utility of longevity interventions. Beyond mouse models, we advocate for studies in companion pets. The Dog Aging Project is an exciting example of translating research in dogs, both to develop a model system and to extend their healthy lifespan as a goal in itself. Finally, we discuss proposed and ongoing intervention studies in humans, unmet needs for validating interventions in humans, and speculate on how differences in survival among human populations may influence intervention efficacy.
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Affiliation(s)
- Mitchell B. Lee
- Department of Pathology, University of Washington, Seattle, WA USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA USA
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22
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Pathak G, Agostino MJ, Bishara K, Capell WR, Fisher JL, Hegde S, Ibrahim BA, Pilarzyk K, Sabin C, Tuczkewycz T, Wilson S, Kelly MP. PDE11A negatively regulates lithium responsivity. Mol Psychiatry 2017; 22:1714-1724. [PMID: 27646265 PMCID: PMC5359083 DOI: 10.1038/mp.2016.155] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 07/13/2016] [Accepted: 07/18/2016] [Indexed: 01/15/2023]
Abstract
Lithium responsivity in patients with bipolar disorder has been genetically associated with Phosphodiesterase 11A (PDE11A), and lithium decreases PDE11A mRNA in induced pluripotent stem cell-derived hippocampal neurons originating from lithium-responsive patients. PDE11 is an enzyme uniquely enriched in the hippocampus that breaks down cyclic AMP and cyclic GMP. Here we determined whether decreasing PDE11A expression is sufficient to increase lithium responsivity in mice. In dorsal hippocampus and ventral hippocampus (VHIPP), lithium-responsive C57BL/6J and 129S6/SvEvTac mice show decreased PDE11A4 protein expression relative to lithium-unresponsive BALB/cJ mice. In VHIPP, C57BL/6J mice also show differences in PDE11A4 compartmentalization relative to BALB/cJ mice. In contrast, neither PDE2A nor PDE10A expression differ among the strains. The compartment-specific differences in PDE11A4 protein expression are explained by a coding single-nucleotide polymorphism (SNP) at amino acid 499, which falls within the GAF-B homodimerization domain. Relative to the BALB/cJ 499T, the C57BL/6J 499A decreases PDE11A4 homodimerization, which removes PDE11A4 from the membrane. Consistent with the observation that lower PDE11A4 expression correlates with better lithium responsiveness, we found that Pde11a knockout mice (KO) given 0.4% lithium chow for 3+ weeks exhibit greater lithium responsivity relative to wild-type (WT) littermates in tail suspension, an antidepressant-predictive assay, and amphetamine hyperlocomotion, an anti-manic predictive assay. Reduced PDE11A4 expression may represent a lithium-sensitive pathophysiology, because both C57BL/6J and Pde11a KO mice show increased expression of the pro-inflammatory cytokine interleukin-6 (IL-6) relative to BALB/cJ and PDE11A WT mice, respectively. Our finding that PDE11A4 negatively regulates lithium responsivity in mice suggests that the PDE11A SNPs identified in patients may be functionally relevant.
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Affiliation(s)
- G Pathak
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | | | - K Bishara
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - W R Capell
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - J L Fisher
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - S Hegde
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - B A Ibrahim
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - K Pilarzyk
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - C Sabin
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | | | - S Wilson
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - M P Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
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23
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Hernández-Zimbrón LF, Perez-Hernández M, Torres-Romero A, Gorostieta-Salas E, Gonzalez-Salinas R, Gulias-Cañizo R, Quiroz-Mercado H, Zenteno E. Markers of Alzheimer's Disease in Primary Visual Cortex in Normal Aging in Mice. BIOMED RESEARCH INTERNATIONAL 2017; 2017:3706018. [PMID: 29138750 PMCID: PMC5613629 DOI: 10.1155/2017/3706018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Accepted: 08/09/2017] [Indexed: 12/18/2022]
Abstract
Aging is the principal risk factor for the development of Alzheimer's disease (AD). The hallmarks of AD are accumulation of the amyloid-β peptide 1-42 (Aβ42) and abnormal hyperphosphorylation of Tau (p-Tau) protein in different areas of the brain and, more recently reported, in the visual cortex. Recently, Aβ42 peptide overproduction has been involved in visual loss. Similar to AD, in normal aging, there is a significant amyloid deposition related to the overactivation of the aforementioned mechanisms. However, the mechanisms associated with visual loss secondary to age-induced visual cortex affectation are not completely understood. Young and aged mice were used as model to analyze the presence of Aβ42, p-Tau, glial-acidic fibrillary protein (GFAP), and presenilin-2, one of the main enzymes involved in Aβ42 production. Our results show a significant increase of Aβ42 deposition in aged mice in the following cells and/or tissues: endothelial cells and blood vessels and neurons of the visual cortex; they also show an increase of the expression of GFAP and presenilin-2 in this region. These results provide a comprehensive framework for the role of Aβ42 in visual loss due to inflammation present with aging and offer some clues for fruitful avenues for the study of healthy aging.
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Affiliation(s)
- Luis Fernando Hernández-Zimbrón
- Research Department, Asociación para Evitar la Ceguera en México, “Hospital Dr. Luis Sanchez Bulnes” IAP, 04030 México City, Mexico
| | - Montserrat Perez-Hernández
- Research Department, Asociación para Evitar la Ceguera en México, “Hospital Dr. Luis Sanchez Bulnes” IAP, 04030 México City, Mexico
- Divisón de Ciencias Biológicas de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Ciudad de México, Mexico
| | - Abigail Torres-Romero
- Research Department, Asociación para Evitar la Ceguera en México, “Hospital Dr. Luis Sanchez Bulnes” IAP, 04030 México City, Mexico
- Divisón de Ciencias Biológicas de la Salud, Universidad Autónoma Metropolitana, Unidad Iztapalapa, Ciudad de México, Mexico
| | - Elisa Gorostieta-Salas
- Neuroscience Division, Institute of Cellular Physiology, UNAM, Ciudad Universitaria, Ciudad de México, Mexico
| | - Roberto Gonzalez-Salinas
- Research Department, Asociación para Evitar la Ceguera en México, “Hospital Dr. Luis Sanchez Bulnes” IAP, 04030 México City, Mexico
| | - Rosario Gulias-Cañizo
- Research Department, Asociación para Evitar la Ceguera en México, “Hospital Dr. Luis Sanchez Bulnes” IAP, 04030 México City, Mexico
- Cell Biology Department, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, Mexico
| | - Hugo Quiroz-Mercado
- Research Department, Asociación para Evitar la Ceguera en México, “Hospital Dr. Luis Sanchez Bulnes” IAP, 04030 México City, Mexico
| | - Edgar Zenteno
- Department of Biochemistry, School of Medicine, UNAM, Ciudad Universitaria, México City, Mexico
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24
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Boddu R, Fan C, Rangarajan S, Sunil B, Bolisetty S, Curtis LM. Unique sex- and age-dependent effects in protective pathways in acute kidney injury. Am J Physiol Renal Physiol 2017; 313:F740-F755. [PMID: 28679590 PMCID: PMC5625098 DOI: 10.1152/ajprenal.00049.2017] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 06/06/2017] [Accepted: 06/28/2017] [Indexed: 12/25/2022] Open
Abstract
Sex and age influence susceptibility to acute kidney injury (AKI), with young females exhibiting lowest incidence. In these studies, we investigated mechanisms which may underlie the sex/age-based dissimilarities. Cisplatin (Cp)-induced AKI resulted in morphological evidence of injury in all groups. A minimal rise in plasma creatinine (PCr) was seen in Young Females, whereas in Aged Females, PCr rose precipitously. Relative to Young Males, Aged Males showed significantly, but temporally, comparably elevated PCr. Notably, Aged Females showed significantly greater mortality, whereas Young Females exhibited none. Tissue KIM-1 and plasma NGAL were significantly lower in Young Females than all others. IGFBP7 levels were modestly increased in both Young groups. IGFBP7 levels in Aged Females were significantly elevated at baseline relative to Aged Males, and increased linearly through day 3, when these levels were comparable in both Aged groups. Plasma cytokine levels similarly showed a pattern of protective effects preferentially in Young Females. Expression of the drug transporter MATE2 did not explain the sex/age distinctions. Heme oxygenase-1 (HO-1) levels (~28-kDa species) showed elevation at day 1 in all groups with highest levels seen in Young Males. Exclusively in Young Females, these levels returned to baseline on day 3, suggestive of a more efficient recovery. In aggregate, we demonstrate, for the first time, a distinctive pattern of response to AKI in Young Females relative to males which appears to be significantly altered in aging. These distinctions may offer novel targets to exploit therapeutically in both females and males in the treatment of AKI.
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Affiliation(s)
- Ravindra Boddu
- Division of Nephrology, Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Chunlan Fan
- Division of Nephrology, Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Sunil Rangarajan
- Division of Nephrology, Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Bhuvana Sunil
- Division of Nephrology, Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Subhashini Bolisetty
- Division of Nephrology, Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Lisa M Curtis
- Division of Nephrology, Nephrology Research and Training Center, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and .,Veterans Affairs Medical Center, Birmingham, Alabama
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25
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MicroRNAs miR-203-3p, miR-664-3p and miR-708-5p are associated with median strain lifespan in mice. Sci Rep 2017; 7:44620. [PMID: 28304372 PMCID: PMC5356331 DOI: 10.1038/srep44620] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 02/10/2017] [Indexed: 02/07/2023] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNA species that have been shown to have roles in multiple processes that occur in higher eukaryotes. They act by binding to specific sequences in the 3’ untranslated region of their target genes and causing the transcripts to be degraded by the RNA-induced silencing complex (RISC). MicroRNAs have previously been reported to demonstrate altered expression in several aging phenotypes such as cellular senescence and age itself. Here, we have measured the expression levels of 521 small regulatory microRNAs (miRNAs) in spleen tissue from young and old animals of 6 mouse strains with different median strain lifespans by quantitative real-time PCR. Expression levels of 3 microRNAs were robustly associated with strain lifespan, after correction for multiple statistical testing (miR-203-3p [β-coefficient = −0.6447, p = 4.8 × 10−11], miR-664-3p [β-coefficient = 0.5552, p = 5.1 × 10−8] and miR-708-5p [β-coefficient = 0.4986, p = 1.6 × 10−6]). Pathway analysis of binding sites for these three microRNAs revealed enrichment of target genes involved in key aging and longevity pathways including mTOR, FOXO and MAPK, most of which also demonstrated associations with longevity. Our results suggests that miR-203-3p, miR-664-3p and miR-708-5p may be implicated in pathways determining lifespan in mammals.
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26
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Abstract
A key characteristic of systems genetics is its reliance on populations that vary to a greater or lesser degree in genetic complexity-from highly admixed populations such as the Collaborative Cross and Diversity Outcross to relatively simple crosses such as sets of consomic strains and reduced complexity crosses. This protocol is intended to help investigators make more informed decisions about choices of resources given different types of questions. We consider factors such as costs, availability, and ease of breeding for common scenarios. In general, we recommend using complementary resources and minimizing depth of resampling of any given genome or strain.
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Affiliation(s)
- Robert W Williams
- Department of Genetics, Genomics and Informatics, University of Tennessee Health Science Center, 77 S. Manassas Street, Memphis, TN, 38163, USA.
| | - Evan G Williams
- Department of Biology, Institute for Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
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27
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Kõks S, Dogan S, Tuna BG, González-Navarro H, Potter P, Vandenbroucke RE. Mouse models of ageing and their relevance to disease. Mech Ageing Dev 2016; 160:41-53. [PMID: 27717883 DOI: 10.1016/j.mad.2016.10.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 09/26/2016] [Accepted: 10/03/2016] [Indexed: 12/28/2022]
Abstract
Ageing is a process that gradually increases the organism's vulnerability to death. It affects different biological pathways, and the underlying cellular mechanisms are complex. In view of the growing disease burden of ageing populations, increasing efforts are being invested in understanding the pathways and mechanisms of ageing. We review some mouse models commonly used in studies on ageing, highlight the advantages and disadvantages of the different strategies, and discuss their relevance to disease susceptibility. In addition to addressing the genetics and phenotypic analysis of mice, we discuss examples of models of delayed or accelerated ageing and their modulation by caloric restriction.
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Affiliation(s)
- Sulev Kõks
- University of Tartu, Tartu, Estonia and Estonian University of Life Sciences, Tartu, Estonia.
| | - Soner Dogan
- Yeditepe University, School of Medicine, Department of Medical Biology, Istanbul, Turkey.
| | - Bilge Guvenc Tuna
- Yeditepe University, School of Medicine, Department of Biophysics, Istanbul, Turkey.
| | - Herminia González-Navarro
- Institute of Health Research-INCLIVA, 46010 Valencia, Spain and CIBER de Diabetes y Enfermedades Metabólicas (CIBERDEM), 28029 Madrid, Spain.
| | - Paul Potter
- Mammalian Genetics Unit, MRC Harwell, Oxfordshire, UK.
| | - Roosmarijn E Vandenbroucke
- Inflammation Research Center, VIB, Ghent, Belgium, Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.
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28
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Lee BP, Pilling LC, Emond F, Flurkey K, Harrison DE, Yuan R, Peters LL, Kuchel GA, Ferrucci L, Melzer D, Harries LW. Changes in the expression of splicing factor transcripts and variations in alternative splicing are associated with lifespan in mice and humans. Aging Cell 2016; 15:903-13. [PMID: 27363602 PMCID: PMC5013025 DOI: 10.1111/acel.12499] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2016] [Indexed: 12/31/2022] Open
Abstract
Dysregulation of splicing factor expression and altered alternative splicing are associated with aging in humans and other species, and also with replicative senescence in cultured cells. Here, we assess whether expression changes of key splicing regulator genes and consequent effects on alternative splicing are also associated with strain longevity in old and young mice, across 6 different mouse strains with varying lifespan (A/J, NOD.B10Sn-H2(b) /J, PWD.Phj, 129S1/SvlmJ, C57BL/6J and WSB/EiJ). Splicing factor expression and changes to alternative splicing were associated with strain lifespan in spleen and to a lesser extent in muscle. These changes mainly involved hnRNP splicing inhibitor transcripts with most changes more marked in spleens of young animals from long-lived strains. Changes in spleen isoform expression were suggestive of reduced cellular senescence and retained cellular proliferative capacity in long-lived strains. Changes in muscle isoform expression were consistent with reduced pro-inflammatory signalling in longer-lived strains. Two splicing regulators, HNRNPA1 and HNRNPA2B1, were also associated with parental longevity in humans, in the InCHIANTI aging study. Splicing factors may represent a driver, mediator or early marker of lifespan in mouse, as expression differences were present in the young animals of long-lived strains. Changes to alternative splicing patterns of key senescence genes in spleen and key remodelling genes in muscle suggest that correct regulation of alternative splicing may enhance lifespan in mice. Expression of some splicing factors in humans was also associated with parental longevity, suggesting that splicing regulation may also influence lifespan in humans.
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Affiliation(s)
| | - Luke C. Pilling
- Epidemiology and Public Health; Institute of Biomedical and Clinical Sciences; University of Exeter Medical School; University of Exeter; Devon UK
| | | | - Kevin Flurkey
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of Aging; Bar Harbor ME USA
| | - David E. Harrison
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of Aging; Bar Harbor ME USA
| | - Rong Yuan
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of Aging; Bar Harbor ME USA
| | - Luanne L. Peters
- The Jackson Laboratory Nathan Shock Centre of Excellence in the Basic Biology of Aging; Bar Harbor ME USA
| | - George A. Kuchel
- UConn Centre on Aging; University of Connecticut Health Centre; Farmington CT USA
| | | | - David Melzer
- Epidemiology and Public Health; Institute of Biomedical and Clinical Sciences; University of Exeter Medical School; University of Exeter; Devon UK
- UConn Centre on Aging; University of Connecticut Health Centre; Farmington CT USA
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29
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Different Mechanisms of Longevity in Long-Lived Mouse and Caenorhabditis elegans Mutants Revealed by Statistical Analysis of Mortality Rates. Genetics 2016; 204:905-920. [PMID: 27638422 DOI: 10.1534/genetics.116.192369] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 08/28/2016] [Indexed: 12/23/2022] Open
Abstract
Mouse and Caenorhabditis elegans mutants with altered life spans are being used to investigate the aging process and how genes determine life span. The survival of a population can be modeled by the Gompertz function, which comprises two parameters. One of these parameters ("G") describes the rate at which mortality accelerates with age and is often described as the "rate of aging." The other parameter ("A") may correspond to the organism's baseline vulnerability to deleterious effects of disease and the environment. We show that, in mice, life-span-extending mutations systematically fail to affect the age-dependent acceleration of mortality (G), but instead affect only baseline vulnerability (A). This remains true even when comparing strains maintained under identical environmental conditions. In contrast, life-span-extending mutations in C. elegans were associated with decreases in G These observations on mortality rate kinetics suggest that the mechanisms of aging in mammals might fundamentally differ from those in nematodes.
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30
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Burd CE, Gill MS, Niedernhofer LJ, Robbins PD, Austad SN, Barzilai N, Kirkland JL. Barriers to the Preclinical Development of Therapeutics that Target Aging Mechanisms. J Gerontol A Biol Sci Med Sci 2016; 71:1388-1394. [PMID: 27535964 PMCID: PMC5055650 DOI: 10.1093/gerona/glw112] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 06/02/2016] [Indexed: 01/08/2023] Open
Abstract
Through the progress of basic science research, fundamental mechanisms that contribute to age-related decline are being described with increasing depth and detail. Although these efforts have identified new drug targets and compounds that extend life span in model organisms, clinical trials of therapeutics that target aging processes remain scarce. Progress in aging research is hindered by barriers associated with the translation of basic science discoveries into the clinic. This report summarizes discussions held at a 2014 Geroscience Network retreat focused on identifying hurdles that currently impede the preclinical development of drugs targeting fundamental aging processes. From these discussions, it was evident that aging researchers have varied perceptions of the ideal preclinical pipeline. To forge a clear and cohesive path forward, several areas of controversy must first be resolved and new tools developed. Here, we focus on five key issues in preclinical drug development (drug discovery, lead compound development, translational preclinical biomarkers, funding, and integration between researchers and clinicians), expanding upon discussions held at the Geroscience Retreat and suggesting areas for further research. By bringing these findings to the attention of the aging research community, we hope to lay the foundation for a concerted preclinical drug development pipeline.
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Affiliation(s)
- Christin E Burd
- Department of Molecular Genetics and.,Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus
| | - Matthew S Gill
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida
| | - Laura J Niedernhofer
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida
| | - Paul D Robbins
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida
| | | | - Nir Barzilai
- Department of Medicine, Division of Endocrinology and.,Institute for Aging Research, Albert Einstein College of Medicine, Bronx, New York
| | - James L Kirkland
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota.
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31
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Fuellen G, Schofield P, Flatt T, Schulz RJ, Boege F, Kraft K, Rimbach G, Ibrahim S, Tietz A, Schmidt C, Köhling R, Simm A. Living Long and Well: Prospects for a Personalized Approach to the Medicine of Ageing. Gerontology 2015; 62:409-16. [PMID: 26675034 DOI: 10.1159/000442746] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/25/2015] [Indexed: 11/19/2022] Open
Abstract
Research into ageing and its underlying molecular basis enables us to develop and implement targeted interventions to ameliorate or cure its consequences. However, the efficacy of interventions often differs widely between individuals, suggesting that populations should be stratified or even individualized. Large-scale cohort studies in humans, similar systematic studies in model organisms as well as detailed investigations into the biology of ageing can provide individual validated biomarkers and mechanisms, leading to recommendations for targeted interventions. Human cohort studies are already ongoing, and they can be supplemented by in silico simulations. Systematic studies in animal models are made possible by the use of inbred strains or genetic reference populations of mice. Combining the two, a comprehensive picture of the various determinants of ageing and 'health span' can be studied in detail, and an appreciation of the relevance of results from model organisms to humans is emerging. The interactions between genotype and environment, particularly the psychosocial environment, are poorly studied in both humans and model organisms, presenting serious challenges to any approach to a personalized medicine of ageing. To increase the success of preventive interventions, we argue that there is a pressing need for an individualized evaluation of interventions such as physical exercise, nutrition, nutraceuticals and calorie restriction mimetics as well as psychosocial and environmental factors, separately and in combination. The expected extension of the health span enables us to refocus health care spending on individual prevention, starting in late adulthood, and on the brief period of morbidity at very old age.
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Affiliation(s)
- Georg Fuellen
- Institute for Biostatistics and Informatics in Medicine und Ageing Research (IBIMA), Rostock University Medical Center, Rostock, Germany
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