151
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Yurov YB, Vorsanova SG, Iourov IY. GIN'n'CIN hypothesis of brain aging: deciphering the role of somatic genetic instabilities and neural aneuploidy during ontogeny. Mol Cytogenet 2009; 2:23. [PMID: 19939257 PMCID: PMC2787505 DOI: 10.1186/1755-8166-2-23] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/25/2009] [Indexed: 08/30/2023] Open
Abstract
Genomic instability (GIN) and chromosome instability (CIN) are two closely related ways to produce a variety of pathogenic conditions, i.e. cancer, neurodegeneration, chromosomal and genomic diseases. The GIN and CIN manifestation that possesses the most appreciable impact on cell physiology and viability is aneuploidy. The latter has been consistently shown to be associated with aging. Classically, it has been considered that a failure of mitotic machinery leads to aneuploidy acquiring throughout aging in dividing cells. Paradoxically, this model is inapplicable for the human brain, which is composed of post-mitotic cells persisting throughout the lifetime. To solve this paradox, we have focused on mosaic neural aneuploidy, a remarkable biomarker of GIN and CIN in the normal and diseased brain (i.e. Alzheimer's disease and ataxia-telangiectasia). Looking through the available data on genomic variations in the developing and adult human central nervous system, we were able to propose a hypothesis suggesting that neural aneuploidy produced during early brain development plays a crucial role of genetic determinant of aging in the healthy and diseased brain.
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Affiliation(s)
- Yuri B Yurov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow 119152, Russia.
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152
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Davies BSJ, Fong LG, Yang SH, Coffinier C, Young SG. The posttranslational processing of prelamin A and disease. Annu Rev Genomics Hum Genet 2009; 10:153-74. [PMID: 19453251 DOI: 10.1146/annurev-genom-082908-150150] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human geneticists have shown that some progeroid syndromes are caused by mutations that interfere with the conversion of farnesyl-prelamin A to mature lamin A. For example, Hutchinson-Gilford progeria syndrome is caused by LMNA mutations that lead to the accumulation of a farnesylated version of prelamin A. In this review, we discuss the posttranslational modifications of prelamin A and their relevance to the pathogenesis and treatment of progeroid syndromes.
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Affiliation(s)
- Brandon S J Davies
- Department of Medicine, University of California, Los Angeles, California 90095, USA.
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153
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Tang NP, Zhou B, Wang B, Yu RB. HTRA1 promoter polymorphism and risk of age-related macular degeneration: a meta-analysis. Ann Epidemiol 2009; 19:740-5. [PMID: 19375943 DOI: 10.1016/j.annepidem.2009.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 01/11/2009] [Accepted: 03/02/2009] [Indexed: 10/20/2022]
Abstract
PURPOSE To clarify the role of human high-temperature requirement A-1 (HTRA1) gene promoter polymorphism (-512G>A) in age-related macular degeneration (AMD). METHODS Relevant studies were identified by searching PubMed and EMBASE database. A logistic regression analysis proposed for molecular association studies was carried out to estimate the genetic effect and the possible genetic model of action. RESULTS Fourteen case-control studies were included in this meta-analysis. There was strong evidence for an association between HTRA1 -512G>A polymorphism and AMD (p < 0.001). The genetic model test indicated that the genetic model was most likely to be co-dominant. Overall, our meta-analysis showed that AA and GA genotypes were associated with increased risk of AMD (AA vs. GG: odds ratio(1) [OR(1)] = 7.46; 95% confidence interval [CI] = 6.16-9.04; GA vs. GG: OR(2) = 2.27, 95% CI = 2.02-2.55). In stratified analysis by ethnicity and age, the genetic effect seemed to be stronger in Caucasians and subjects > or =73 years of age than in Asians and subjects <73 years of age. When subgroup analysis was conducted by AMD type, significant association was noted for wet AMD but not for dry AMD. CONCLUSIONS This meta-analysis summarizes the strong evidence for an association between HTRA1 -512G>A polymorphism and AMD and indicates a co-dominant model of action.
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Affiliation(s)
- Na-Ping Tang
- National Shanghai Center for New Drug Safety Evaluation and Research, Shanghai Institute of Pharmaceutical Industry, Shanghai, China.
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154
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Mérida I, Avila-Flores A, García J, Merino E, Almena M, Torres-Ayuso P. Diacylglycerol kinase alpha, from negative modulation of T cell activation to control of cancer progression. ACTA ACUST UNITED AC 2009; 49:174-88. [PMID: 19534031 DOI: 10.1016/j.advenzreg.2009.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Isabel Mérida
- Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Darwin 3, Campus de Cantoblanco, E-28049 Madrid, Spain.
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155
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Wu FX, Zhang WJ. Dynamic-model-based method for selecting significantly expressed genes from time-course expression profiles. ACTA ACUST UNITED AC 2009; 14:16-22. [PMID: 19527959 DOI: 10.1109/titb.2009.2025125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
This paper proposes a dynamic-model-based method for selecting significantly expressed (SE) genes from their time-course expression profiles. A gene is considered to be SE if its time-course expression profile is more likely time-dependent than random. The proposed method describes a time-dependent gene expression profile by a nonzero-order autoregressive (AR) model, and a time-independent gene expression profile by a zero-order AR model. Akaike information criterion (AIC) is used to compare the models and subsequently determine whether a time-course gene expression profile is time-independent or time-dependent. The performance of the proposed method is investigated on both a synthetic dataset and a real-life biological dataset in terms of the false discovery rate (FDR) and the false nondiscovery rate (FNR). The results show that the proposed method is valid for selecting SE genes from their time-course expression profiles.
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Affiliation(s)
- Fang-Xiang Wu
- Department of Mechanical Engineering, Division of Biomedical Engineering, University of Saskatchewan, Saskatoon, SK S7N5A9, Canada.
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156
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Chesnokova V, Wong C, Zonis S, Gruszka A, Wawrowsky K, Ren SG, Benshlomo A, Yu R. Diminished pancreatic beta-cell mass in securin-null mice is caused by beta-cell apoptosis and senescence. Endocrinology 2009; 150:2603-10. [PMID: 19213844 PMCID: PMC2689808 DOI: 10.1210/en.2008-0972] [Citation(s) in RCA: 23] [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: 11/19/2022]
Abstract
Pituitary tumor transforming gene (PTTG) encodes a securin protein critical in regulating chromosome separation. PTTG-null (PTTG(-/-)) mice exhibit pancreatic beta-cell hypoplasia and insulinopenic diabetes. We tested whether PTTG deletion causes beta-cell senescence, resulting in diminished beta-cell mass. We examined beta-cell mass, proliferation, apoptosis, neogenesis, cell size, and senescence in PTTG(-/-) and WT mice from embryo to young adulthood before diabetes is evident. The roles of cyclin-dependent kinase inhibitors and DNA damage in the pathogenesis of diabetes in PTTG(-/-) mice were also addressed. Relative beta-cell mass in PTTG(-/-) mice began to decrease at 2-3 wk, whereas beta-cell proliferation rate was initially normal but decreased in PTTG(-/-) mice beginning at 2 months. Apoptosis was also much more evident in PTTG(-/-) mice. At 1 month, beta-cell neogenesis was robust in wild-type mice but was absent in PTTG(-/-) mice. In addition, the size of beta-cells became larger and macronuclei were prominent in PTTG(-/-) animals. Senescence-associated beta-galactosidase was also active in PTTG(-/-) beta-cells at 1 month. Cyclin-dependent kinase inhibitor p21 was progressively up-regulated in PTTG(-/-) islets, and p21 deletion partially rescued PTTG(-/-) mice from development of diabetes. mRNA array showed that DNA damage-associated genes were activated in PTTG(-/-) islets. We conclude that beta-cell apoptosis and senescence contribute to the diminished beta-cell mass in PTTG(-/-) mice, likely secondary to DNA damage. Our results also suggest that ductal progenitor beta-cells are exhausted by excessive neogenesis induced by apoptosis in PTTG(-/-) mice.
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Affiliation(s)
- Vera Chesnokova
- Division of Endocrinology, Diabetes, and Metabolism, Cedars-Sinai Medical Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90048, USA
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157
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Arendt T, Mosch B, Morawski M. Neuronal aneuploidy in health and disease: a cytomic approach to understand the molecular individuality of neurons. Int J Mol Sci 2009; 10:1609-1627. [PMID: 19468329 PMCID: PMC2680637 DOI: 10.3390/ijms10041609] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 04/07/2009] [Accepted: 04/09/2009] [Indexed: 02/07/2023] Open
Abstract
Structural variation in the human genome is likely to be an important mechanism for neuronal diversity and brain disease. A combination of multiple different forms of aneuploid cells due to loss or gain of whole chromosomes giving rise to cellular diversity at the genomic level have been described in neurons of the normal and diseased adult human brain. Here, we describe recent advances in molecular neuropathology based on the combination of slide-based cytometry with molecular biological techniques that will contribute to the understanding of genetic neuronal heterogeneity in the CNS and its potential impact on Alzheimer's disease and age-related disorders.
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Affiliation(s)
- Thomas Arendt
- Author to whom correspondence should be addressed; E-Mail:
; Tel. +49-341-9725721; Fax: +49-341-9725729
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158
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Increased expression of the Hutchinson-Gilford progeria syndrome truncated lamin A transcript during cell aging. Eur J Hum Genet 2009; 17:928-37. [PMID: 19172989 DOI: 10.1038/ejhg.2008.270] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Most cases of the segmental progeroid syndrome, Hutchinson-Gilford progeria syndrome (HGPS), are caused by a de novo dominant mutation within a single codon of the LMNA gene. This mutation leads to the increased usage of an internal splice site that generates an alternative lamin A transcript with an internal deletion of 150 nucleotides, called lamin A Delta 150. The LMNA gene encodes two major proteins of the inner nuclear lamina, lamins A and C, but not much is known about their expression levels. Determination of the overall expression levels of the LMNA gene transcripts is an important step to further the understanding of the HGPS. In this study, we have performed absolute quantification of the lamins A, C and A Delta 150 transcripts in primary dermal fibroblasts from HGPS patients and unaffected age-matched and parent controls. We show that the lamin A Delta 150 transcript is present in unaffected controls but its expression is >160-fold lower than that in samples from HGPS patients. Analysis of transcript expression during in vitro aging shows that although the levels of lamin A and lamin C transcripts remain unchanged, the lamin A Delta 150 transcript increases in late passage cells from HGPS patients and parental controls. This study provides a new method for LMNA transcript analysis and insights into the expression of the LMNA gene in HGPS and normal cells.
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159
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Aging-related loss of the chromatin protein HMGB2 in articular cartilage is linked to reduced cellularity and osteoarthritis. Proc Natl Acad Sci U S A 2009; 106:1181-6. [PMID: 19139395 DOI: 10.1073/pnas.0806062106] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Osteoarthritis (OA) is the most common joint disease and typically begins with an aging-related disruption of the articular cartilage surface. Mechanisms leading to the aging-related cartilage surface degeneration remain to be determined. Here, we demonstrate that nonhistone chromatin protein high-mobility group box (HMGB) protein 2 is uniquely expressed in the superficial zone (SZ) of human articular cartilage. In human and murine cartilage, there is an aging-related loss of HMGB2 expression, ultimately leading to its complete absence. Mice genetically deficient in HMGB2 (Hmgb2(-/-)) show earlier onset of and more severe OA. This is associated with a profound reduction in cartilage cellularity attributable to increased cell death. These cellular changes precede glycosaminoglycan depletion and progressive cartilage erosions. Chondrocytes from Hmgb2(-/-) mice are more susceptible to apoptosis induction in vitro. In conclusion, HMGB2 is a transcriptional regulator specifically expressed in the SZ of human articular cartilage and supports chondrocyte survival. Aging is associated with a loss of HMGB2 expression and reduced cellularity, and this contributes to the development of OA.
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160
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Abstract
Homeostasis is a key feature of cellular lifespan. Maintenance of cellular homeostasis influences the rate of aging and is determined by several factors, including efficient proteolysis of damaged proteins. Protein degradation is predominantly catalyzed by the proteasome. Specifically, the proteasome is responsible for cell clearance of abnormal, denatured or in general damaged proteins as well as for the regulated degradation of short-lived proteins. As proteasome has an impaired function during aging, emphasis has been given recently in identifying ways of its activation. A number of studies have shown that the proteasome can be activated by genetic manipulations as well as by factors that affect its conformation and stability. Importantly the developed proteasome activated cell lines exhibit an extended lifespan. This review article discusses in details the various factors that are involved in proteasome biosynthesis and assembly and how they contribute to its activation. Finally as few natural compounds have been identified having proteasome activation properties, we discuss the advantages of this novel antiaging strategy.
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Affiliation(s)
- Niki Chondrogianni
- National Hellenic Research Foundation, Institute of Biological Research and Biotechnology, Athens 11635, Greece
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161
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González JM, Navarro-Puche A, Casar B, Crespo P, Andrés V. Fast regulation of AP-1 activity through interaction of lamin A/C, ERK1/2, and c-Fos at the nuclear envelope. ACTA ACUST UNITED AC 2008; 183:653-66. [PMID: 19015316 PMCID: PMC2582892 DOI: 10.1083/jcb.200805049] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Sequestration of c-Fos at the nuclear envelope (NE) through interaction with A-type lamins suppresses AP-1–dependent transcription. We show here that c-Fos accumulation within the extraction-resistant nuclear fraction (ERNF) and its interaction with lamin A are reduced and enhanced by gain-of and loss-of ERK1/2 activity, respectively. Moreover, hindering ERK1/2-dependent phosphorylation of c-Fos attenuates its release from the ERNF induced by serum and promotes its interaction with lamin A. Accordingly, serum stimulation rapidly releases preexisting c-Fos from the NE via ERK1/2-dependent phosphorylation, leading to a fast activation of AP-1 before de novo c-Fos synthesis. Moreover, lamin A–null cells exhibit increased AP-1 activity and reduced levels of c-Fos phosphorylation. We also find that active ERK1/2 interacts with lamin A and colocalizes with c-Fos and A-type lamins at the NE. Thus, NE-bound ERK1/2 functions as a molecular switch for rapid mitogen-dependent AP-1 activation through phosphorylation-induced release of preexisting c-Fos from its inhibitory interaction with lamin A/C.
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Affiliation(s)
- José María González
- Laboratory of Vascular Biology, Department of Molecular and Cellular Pathology and Therapy, Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Cientificas (CSIC), Valencia, Spain
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162
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Ding SL, Shen CY. Model of human aging: recent findings on Werner's and Hutchinson-Gilford progeria syndromes. Clin Interv Aging 2008; 3:431-44. [PMID: 18982914 PMCID: PMC2682376 DOI: 10.2147/cia.s1957] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The molecular mechanisms involved in human aging are complicated. Two progeria syndromes, Werner's syndrome (WS) and Hutchinson-Gilford progeria syndrome (HGPS), characterized by clinical features mimicking physiological aging at an early age, provide insights into the mechanisms of natural aging. Based on recent findings on WS and HGPS, we suggest a model of human aging. Human aging can be triggered by two main mechanisms, telomere shortening and DNA damage. In telomere-dependent aging, telomere shortening and dysfunction may lead to DNA damage responses which induce cellular senescence. In DNA damage-initiated aging, DNA damage accumulates, along with DNA repair deficiencies, resulting in genomic instability and accelerated cellular senescence. In addition, aging due to both mechanisms (DNA damage and telomere shortening) is strongly dependent on p53 status. These two mechanisms can also act cooperatively to increase the overall level ofgenomic instability, triggering the onset of human aging phenotypes.
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Affiliation(s)
- Shian-Ling Ding
- Department of Nursing, Kang-Ning Junior College of Medical Care and Management,Taipei,Taiwan.
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163
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Abstract
Two paradigms central to geroscience research are that aging is associated with increased oxidative stress and increased cancer risk. Therefore, it could be deduced that cancers arising with ageing will show evidence of increased oxidative stress. Recent studies of gene expression in age-controlled breast cancer cases indicate that this deduction is false, posing parallax views of these two paradigms, and highlighting the unanswered question: does ageing cause or simply permit cancer development?
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Affiliation(s)
- Christopher C Benz
- Christopher C. Benz and Christina Yau are at the Buck Institute for Age Research, Novato, California 94945, USA
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164
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Gordon LB, Harling-Berg CJ, Rothman FG. Highlights of the 2007 Progeria Research Foundation scientific workshop: progress in translational science. J Gerontol A Biol Sci Med Sci 2008; 63:777-87. [PMID: 18772465 DOI: 10.1093/gerona/63.8.777] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Leslie B Gordon
- Warren Alpert Medical School of Brown University, Providence, RI 02912, USA.
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165
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Li Z, Wright FA, Royland J. Age-dependent variability in gene expression in male Fischer 344 rat retina. Toxicol Sci 2008; 107:281-92. [PMID: 18936298 DOI: 10.1093/toxsci/kfn215] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Recent evidence suggests that older adults may be a sensitive population with regard to environmental exposure to toxic compounds. One source of this sensitivity could be an enhanced variability in response. Studies on phenotypic differences have suggested that variation in response does increase with age. However, few reports address the question of variation in gene expression as an underlying cause for increased variability of phenotypic response in the aged. In this study, we utilized global analysis to compare variation in constitutive gene expression in the retinae of young (4 months), middle-aged (11 months), and aged (23 months) Fischer 344 rats. Three hundred and forty transcripts were identified in which variance in expression increased from 4 to 23 months of age, while only 12 transcripts were found for which it decreased. Functional roles for identified genes were clustered in basic biological categories including cell communication, function, metabolism, and response to stimuli. Our data suggest that population stochastically induced variability should be considered in assessing sensitivity due to old age.
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Affiliation(s)
- Zhen Li
- Department of Biostatistics, Carolina Environmental Bioinformatics Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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166
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Cheadle C, Nesterova M, Watkins T, Barnes KC, Hall JC, Rosen A, Becker KG, Cho-Chung YS. Regulatory subunits of PKA define an axis of cellular proliferation/differentiation in ovarian cancer cells. BMC Med Genomics 2008; 1:43. [PMID: 18822129 PMCID: PMC2577111 DOI: 10.1186/1755-8794-1-43] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 09/26/2008] [Indexed: 11/20/2022] Open
Abstract
Background The regulatory subunit of cAMP-dependent protein kinase (PKA) exists in two isoforms, RI and RII, which distinguish the PKA isozymes, type I (PKA-I) and type II (PKA-II). Evidence obtained from a variety of different experimental approaches has shown that the relative levels of type I and type II PKA in cells can play a major role in determining the balance between cell growth and differentiation. In order to characterize the effect of PKA type I and type II regulatory subunits on gene transcription at a global level, the PKA regulatory subunit genes for RIα and RIIβ were stably transfected into cells of the ovarian cancer cell line (OVCAR8). Results RIα transfected cells exhibit hyper-proliferative growth and RIIβ transfected cells revert to a relatively quiescent state. Profiling by microarray revealed equally profound changes in gene expression between RIα, RIIβ, and parental OVCAR cells. Genes specifically up-regulated in RIα cells were highly enriched for pathways involved in cell growth while genes up-regulated in RIIβ cells were enriched for pathways involved in differentiation. A large group of genes (~3600) was regulated along an axis of proliferation/differentiation between RIα, parental, and RIIβ cells. RIα/wt and RIIβ/wt gene regulation was shown by two separate and distinct gene set analytical methods to be strongly cross-correlated with a generic model of cellular differentiation. Conclusion Overexpression of PKA regulatory subunits in an ovarian cancer cell line dramatically influences the cell phenotype. The proliferation phenotype is strongly correlated with recently identified clinical biomarkers predictive of poor prognosis in ovarian cancer suggesting a possible pivotal role for PKA regulation in disease progression.
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Affiliation(s)
- Chris Cheadle
- Cellular Biochemistry Section, National Cancer Institute, Bethesda, USA.
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167
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Ohshima S. Abnormal mitosis in hypertetraploid cells causes aberrant nuclear morphology in association with H2O2-induced premature senescence. Cytometry A 2008; 73:808-15. [DOI: 10.1002/cyto.a.20604] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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168
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Chang IY, Jin M, Yoon SP, Youn CK, Yoon Y, Moon SP, Hyun JW, Jun JY, You HJ. Senescence-dependent MutS alpha dysfunction attenuates mismatch repair. Mol Cancer Res 2008; 6:978-89. [PMID: 18567801 DOI: 10.1158/1541-7786.mcr-07-0380] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DNA damage and mutations in the genome increase with age. To determine the potential mechanisms of senescence-dependent increases in genomic instability, we analyzed DNA mismatch repair (MMR) efficiency in young and senescent human colonic fibroblast and human embryonic lung fibroblast. It was found that MMR activity is significantly reduced in senescent cells. Western blot and immunohistochemistry analysis revealed that hMSH2 and MSH6 protein (MutS alpha complex), which is a known key component in the MMR pathway, is markedly down-regulated in senescent cells. Moreover, the addition of purified MutS alpha to extracts from senescent cells led to the restoration of MMR activity. Semiquantitative reverse transcription-PCR analysis exhibited that MSH2 mRNA level is reduced in senescent cells. In addition, a decrease in E2F transcriptional activity in senescent cells was found to be crucial for MSH2 suppression. E2F1 small interfering RNA expression reduced hMSH2 expression and MMR activity in young human primary fibroblast cells. Importantly, expression of E2F1 in quiescent cells restored the MSH2 expression as well as MMR activity, whereas E2F1-infected senescent cells exhibited no restoration of MSH2 expression and MMR activity. These results indicate that the suppression of E2F1 transcriptional activity in senescent cells lead to stable repression of MSH2, followed by a induction of MutS alpha dysfunction, which results in a reduced cellular MMR capacity in senescent cells.
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Affiliation(s)
- In-Youb Chang
- Korean DNA Repair Research Center, Republic of Korea (South Korea)
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169
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Abstract
Using a suppressive subtractive hybridization system, we identified CSIG (cellular senescence-inhibited gene protein; RSL1D1) that was abundant in young human diploid fibroblast cells but declined upon replicative senescence. Overexpression or knockdown of CSIG did not influence p21(Cip1) and p16(INK4a) expressions. Instead, CSIG negatively regulated PTEN and p27(Kip1) expressions, in turn promoting cell proliferation. In PTEN-silenced HEK 293 cells and PTEN-deficient human glioblastoma U87MG cells, the effect of CSIG on p27(Kip1) expression and cell division was abolished, suggesting that PTEN was required for the role of CSIG on p27(Kip1) regulation and cell cycle progression. Investigation into the underlying mechanism revealed that the regulation of PTEN by CSIG was achieved through a translational suppression mechanism. Further study showed that CSIG interacted with PTEN mRNA in the 5' untranslated region (UTR) and that knockdown of CSIG led to increased luciferase activity of a PTEN 5' UTR-luciferase reporter. Moreover, overexpression of CSIG significantly delayed the progression of replicative senescence, while knockdown of CSIG expression accelerated replicative senescence. Knockdown of PTEN diminished the effect of CSIG on cellular senescence. Our findings indicate that CSIG acts as a novel regulatory component of replicative senescence, which requires PTEN as a mediator and involves in a translational regulatory mechanism.
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170
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Proteome-based identification of plasma proteins associated with hippocampal metabolism in early Alzheimer's disease. J Neurol 2008; 255:1712-20. [PMID: 19156487 DOI: 10.1007/s00415-008-0006-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 05/15/2008] [Accepted: 05/20/2008] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND METHODS There is an urgent need for peripheral surrogates of Alzheimer's disease (AD) that accurately reflect disease state and severity as well as correlate with key features of its neuropathology. The aim of this study was to identify plasma proteins associated with known in vivo markers of disease activity. In an earlier proteomic study of plasma, we discovered a panel of 15 proteins that were differentially expressed in AD and further validated complement factor-H (CFH) and alpha-2-macroglobulin (A2M) as AD-specific plasma biomarkers. In the present study, we extended these findings by testing the associations of these plasma proteins with neuro-imaging measures of disease progression in AD. We combined (1)H-magnetic resonance spectroscopy of the hippocampus and MRI-based hippocampal volumetry with proteomic analysis of plasma in early AD and mild cognitive impairment (MCI) to achieve this goal. Using (1)H-magnetic resonance spectroscopy, we derived estimates of the hippocampal metabolite ratio N-acetylaspartate/myo-inositol (NAA/mI), a biochemical measure that is associated with cognitive decline in early AD. We also undertook a proteomic analysis of plasma in these individuals using two-dimensional gel electrophoresis (2DGE). RESULTS We observed that two plasma proteins previously shown to be differentially expressed in AD, complement factor-H (CFH) and alpha-2-macroglobulin (A2M) showed significant positive correlations with hippocampal NAA/mI ratio in AD. CONCLUSIONS The association of plasma CFH and A2M with hippocampal NAA/mI in this cohort of AD subjects suggests that these proteins may reflect disease progression in early AD. These findings warrant validation in large population-based datasets.
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171
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Kriete A, Mayo KL, Yalamanchili N, Beggs W, Bender P, Kari C, Rodeck U. Cell autonomous expression of inflammatory genes in biologically aged fibroblasts associated with elevated NF-kappaB activity. IMMUNITY & AGEING 2008; 5:5. [PMID: 18631391 PMCID: PMC2483950 DOI: 10.1186/1742-4933-5-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Accepted: 07/16/2008] [Indexed: 02/06/2023]
Abstract
BACKGROUND Chronic inflammation is a well-known corollary of the aging process and is believed to significantly contribute to morbidity and mortality of many age-associated chronic diseases. However, the mechanisms that cause age-associated inflammatory changes are not well understood. Particularly, the contribution of cell stress responses to age-associated inflammation in 'non-inflammatory' cells remains poorly defined. The present cross-sectional study focused on differences in molecular signatures indicative of inflammatory states associated with biological aging of human fibroblasts from donors aged 22 to 92 years. RESULTS Gene expression profiling revealed elevated steady-state transcript levels consistent with a chronic inflammatory state in fibroblast cell-strains obtained from older donors. We also observed enhanced NF-kappaB DNA binding activity in a subset of strains, and the NF-kappaB profile correlated with mRNA expression levels characteristic of inflammatory processes, which include transcripts coding for cytokines, chemokines, components of the complement cascade and MHC molecules. This intrinsic low-grade inflammatory state, as it relates to aging, occurs in cultured cells irrespective of the presence of other cell types or the in vivo context. CONCLUSION Our results are consistent with the view that constitutive activation of inflammatory pathways is a phenomenon prevalent in aged fibroblasts. It is possibly part of a cellular survival process in response to compromised mitochondrial function. Importantly, the inflammatory gene expression signature described here is cell autonomous, i.e. occurs in the absence of prototypical immune or pro-inflammatory cells, growth factors, or other inflammatory mediators.
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Affiliation(s)
- Andres Kriete
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Bossone Research Center, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
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Oender K, Trost A, Lanschuetzer C, Laimer M, Emberger M, Breitenbach M, Richter K, Hintner H, Bauer JW. Cytokeratin-related loss of cellular integrity is not a major driving force of human intrinsic skin aging. Mech Ageing Dev 2008; 129:563-71. [PMID: 18582489 DOI: 10.1016/j.mad.2008.05.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2007] [Revised: 05/13/2008] [Accepted: 05/16/2008] [Indexed: 12/15/2022]
Abstract
The contribution of extracellular matrix components to intrinsic skin aging has been investigated thoroughly, however, there is little information as to the role of the cytoskeletal proteins in this process. Therefore, we compared the expression of the constituents of the cytoskeleton, keratins 1-23 (K1-K23) as well as junction-plakoglobin (JUP), alpha-tubulin (TUBA), and beta-actin (ACTB) in human foreskins of both young (mean 6.4 years) and aged (mean 54.3 years) individuals. By applying RNA expression analysis to intrinsically aged human skin, we demonstrated that the mRNA levels of the genes for K1, K3, K4, K9, K13, K15, K18, K19 and K20 are downregulated in aged skin, K5 and K14 are unchanged, and K2, K16 and K17 are upregulated in aged skin. The mRNA data were confirmed on the protein level. This diverse picture is in contrast to other cytoskeletal proteins including components of the desmosome (JUP), microtubuli (TUBA) and microfilaments (ACTB) - often regarded as house-keeping genes - that were all reduced in aged skin. These cytoskeletal features of intrinsic aging highlight the importance of the cellular compartment in this process and demonstrate that special attention has to be given to RNA as well as protein normalization in aging studies.
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Affiliation(s)
- Kamil Oender
- Department of Dermatology, Muellner Hauptstrasse 48, A-5020 Salzburg, Austria
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174
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Debacq-Chainiaux F, Pascal T, Boilan E, Bastin C, Bauwens E, Toussaint O. Screening of senescence-associated genes with specific DNA array reveals the role of IGFBP-3 in premature senescence of human diploid fibroblasts. Free Radic Biol Med 2008; 44:1817-32. [PMID: 18329388 DOI: 10.1016/j.freeradbiomed.2008.02.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Revised: 12/29/2007] [Accepted: 02/05/2008] [Indexed: 02/05/2023]
Abstract
Repeated exposures to sublethal concentrations of tert-butylhydroperoxide and ethanol trigger premature senescence of WI-38 human diploid fibroblasts. We found 16 replicative senescence-related genes with similar alterations in expression level in replicative senescence and two models of stress-induced premature senescence. Among these genes was IGFBP-3. Using a siRNA approach, we showed that IGFBP-3 regulates the appearance of several biomarkers of senescence after repeated exposures of WI-38 fibroblasts to tert-butylhydroperoxide and ethanol.
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Affiliation(s)
- Florence Debacq-Chainiaux
- Unit of Research on Cellular Biology, Department of Biology, University of Namur, Rue de Bruxelles, B-5000 Namur, Belgium
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175
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Abstract
Primarily known for its role as major microtubule organizing center, the centrosome is increasingly being recognized for its functional significance in key cell cycle regulating events. We are now at the beginning of understanding the centrosome’s functional complexities and its major impact on directing complex interactions and signal transduction cascades important for cell cycle regulation. The centrosome orchestrates entry into mitosis, anaphase onset, cytokinesis, G1/S transition, and monitors DNA damage. Recently, the centrosome has also been recognized as major docking station where regulatory complexes accumulate including kinases and phosphatases as well as numerous other cell cycle regulators that utilize the centrosome as platform to coordinate multiple cell cycle-specific functions. Vesicles that are translocated along microtubules to and away from centrosomes may also carry enzymes or substrates that use centrosomes as main docking station. The centrosome’s role in various diseases has been recognized and a wealth of data has been accumulated linking dysfunctional centrosomes to cancer, Alstrom syndrome, various neurological disorders, and others. Centrosome abnormalities and dysfunctions have been associated with several types of infertility. The present review highlights the centrosome’s significant roles in cell cycle events in somatic and reproductive cells and discusses centrosome abnormalities and implications in disease.
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Affiliation(s)
- Heide Schatten
- Department of Veterinary Pathobiology, University of Missouri, 1600 E Rollins Street, Columbia, MO 65211, USA.
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176
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Breusing N, Grune T. Regulation of proteasome-mediated protein degradation during oxidative stress and aging. Biol Chem 2008; 389:203-9. [PMID: 18208355 DOI: 10.1515/bc.2008.029] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Protein degradation is a physiological process required to maintain cellular functions. There are distinct proteolytic systems for different physiological tasks under changing environmental and pathophysiological conditions. The proteasome is responsible for the removal of oxidatively damaged proteins in the cytosol and nucleus. It has been demonstrated that proteasomal degradation increases due to mild oxidation, whereas at higher oxidant levels proteasomal degradation decreases. Moreover, the proteasome itself is affected by oxidative stress to varying degrees. The ATP-stimulated 26S proteasome is sensitive to oxidative stress, whereas the 20S form seems to be resistant. Non-degradable protein aggregates and cross-linked proteins are able to bind to the proteasome, which makes the degradation of other misfolded and damaged proteins less efficient. Consequently, inhibition of the proteasome has dramatic effects on cellular aging processes and cell viability. It seems likely that during oxidative stress cells are able to keep the nuclear protein pool free of damage, while cytosolic proteins may accumulate. This is because of the high proteasome content in the nucleus, which protects the nucleus from the formation and accumulation of non-degradable proteins. In this review we highlight the regulation of the proteasome during oxidative stress and aging.
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Affiliation(s)
- Nicolle Breusing
- Institute of Biological Chemistry and Nutrition, University of Hohenheim, Garbenstrasse 28, D-70593 Stuttgart, Germany
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177
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Burke B, Stewart CL. The laminopathies: the functional architecture of the nucleus and its contribution to disease. Annu Rev Genomics Hum Genet 2008; 7:369-405. [PMID: 16824021 DOI: 10.1146/annurev.genom.7.080505.115732] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most inherited diseases are associated with mutations in a specific gene. Often, mutations in two or more different genes result in diseases with a similar phenotype. Rarely do different mutations in the same gene result in a multitude of seemingly different and unrelated diseases. Mutations in the Lamin A gene (LMNA), which encodes largely ubiquitously expressed nuclear proteins (A-type lamins), are associated with at least eight different diseases, collectively called the laminopathies. Studies examining how different tissue-specific diseases arise from unique LMNA mutations are providing unanticipated insights into the structural organization of the nucleus, and how disruption of this organization relates to novel mechanisms of disease.
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Affiliation(s)
- Brian Burke
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, Florida 32610
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178
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Pereira S, Bourgeois P, Navarro C, Esteves-Vieira V, Cau P, De Sandre-Giovannoli A, Lévy N. HGPS and related premature aging disorders: from genomic identification to the first therapeutic approaches. Mech Ageing Dev 2008; 129:449-59. [PMID: 18513784 DOI: 10.1016/j.mad.2008.04.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Revised: 03/27/2008] [Accepted: 04/06/2008] [Indexed: 01/25/2023]
Abstract
Progeroid syndromes are heritable human disorders displaying features that recall premature ageing. In these syndromes, premature aging is defined as "segmental" since only some of its features are accelerated. A number of cellular biological pathways have been linked to aging, including regulation of the insulin/growth hormone axis, pathways involving ROS metabolism, caloric restriction, and DNA repair. The number of identified genes associated with progeroid syndromes has increased in recent years, possibly shedding light as well on mechanisms underlying ageing in general. Among these, premature aging syndromes related to alterations of the LMNA gene have recently been identified. This review focuses on Hutchinson-Gilford Progeria syndrome and Restrictive Dermopathy, two well-characterized Lamin-associated premature aging syndromes, pointing out the current knowledge concerning their pathophysiology and the development of possible therapeutic approaches.
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Affiliation(s)
- Sandrine Pereira
- INSERM U910, Faculté de Médecine la Timone, 27 Boulevard Jean Moulin, Marseille, France
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179
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Li SKM, Smith DK, Leung WY, Cheung AMS, Lam EWF, Dimri GP, Yao KM. FoxM1c counteracts oxidative stress-induced senescence and stimulates Bmi-1 expression. J Biol Chem 2008; 283:16545-53. [PMID: 18408007 DOI: 10.1074/jbc.m709604200] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The Forkhead box transcription factor FoxM1 is expressed in proliferating cells. When it was depleted in mice and cell lines, cell cycle defects and chromosomal instability resulted. Premature senescence was observed in embryonic fibroblasts derived from FoxM1 knock-out mice, but the underlying cause has remained unclear. To investigate whether FoxM1 can protect cells against stress-induced premature senescence, we established NIH3T3 lines with doxycycline-inducible overexpression of FoxM1c. Treatment of these lines with sublethal doses (20 and 100 microm) of H(2)O(2) induced senescence with senescence-associated beta-galactosidase expression and elevated levels of p53 and p21. Induction of FoxM1c expression markedly suppressed senescence and expression of p53 and p21. Consistent with down-regulation of the p19(Arf)-p53 pathway, p19(Arf) levels decreased while expression of the Polycomb group protein Bmi-1 was induced. That Bmi-1 is a downstream target of FoxM1c was further supported by the dose-dependent induction of Bmi-1 by FoxM1c at both the protein and mRNA levels, and FoxM1 and Bmi-1 reached maximal levels in cells at the G(2)/M phase. Depletion of FoxM1 by RNA interference decreased Bmi-1 expression. Using Bmi-1 promoter reporters with wild-type and mutated c-Myc binding sites and short hairpin RNAs targeting c-Myc, we further demonstrated that FoxM1c activated Bmi-1 expression via c-Myc, which was recently reported to be regulated by FoxM1c. Our results reveal a functional link between FoxM1c, c-Myc, and Bmi-1, which are major regulators of tumorigenesis. This link has important implications for the regulation of cell proliferation and senescence by FoxM1 and Bmi-1.
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Affiliation(s)
- Samuel K M Li
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
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180
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Affiliation(s)
- Carol A. Cooper
- The chief operating officer of Dermal Research Laboratories, a product development and licensing company holding patents and patents pending on the topical and oral use of hyaluronic acid, in Kansas City, Missouri
| | - Karen K. Brown
- The chief technical officer at Dermal Research Laboratories
| | - Chris D. Meletis
- Executive director of the Institute for Healthy Aging, a non-profit educational group, in Carson City, Nevada, and an associate professor of natural pharmacology at the National College of Naturopathic Medicine, in Portland, Oregon
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181
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Activation of cellular death programs associated with immunosenescence-like phenotype in TPPII knockout mice. Proc Natl Acad Sci U S A 2008; 105:5177-82. [PMID: 18362329 DOI: 10.1073/pnas.0801413105] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The giant cytosolic protease tripeptidyl peptidase II (TPPII) has been implicated in the regulation of proliferation and survival of malignant cells, particularly lymphoma cells. To address its functions in normal cellular and systemic physiology we have generated TPPII-deficient mice. TPPII deficiency activates cell type-specific death programs, including proliferative apoptosis in several T lineage subsets and premature cellular senescence in fibroblasts and CD8(+) T cells. This coincides with up-regulation of p53 and dysregulation of NF-kappaB. Prominent degenerative alterations at the organismic level were a decreased lifespan and symptoms characteristic of immunohematopoietic senescence. These symptoms include accelerated thymic involution, lymphopenia, impaired proliferative T cell responses, extramedullary hematopoiesis, and inflammation. Thus, TPPII is important for maintaining normal cellular and systemic physiology, which may be relevant for potential therapeutic applications of TPPII inhibitors.
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182
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Yau C, Fedele V, Roydasgupta R, Fridlyand J, Hubbard A, Gray JW, Chew K, Dairkee SH, Moore DH, Schittulli F, Tommasi S, Paradiso A, Albertson DG, Benz CC. Aging impacts transcriptomes but not genomes of hormone-dependent breast cancers. Breast Cancer Res 2008; 9:R59. [PMID: 17850661 PMCID: PMC2216076 DOI: 10.1186/bcr1765] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 08/21/2007] [Accepted: 09/12/2007] [Indexed: 11/29/2022] Open
Abstract
Introduction Age is one of the most important risk factors for human malignancies, including breast cancer; in addition, age at diagnosis has been shown to be an independent indicator of breast cancer prognosis. Except for inherited forms of breast cancer, however, there is little genetic or epigenetic understanding of the biological basis linking aging with sporadic breast cancer incidence and its clinical behavior. Methods DNA and RNA samples from matched estrogen receptor (ER)-positive sporadic breast cancers diagnosed in either younger (age ≤ 45 years) or older (age ≥ 70 years) Caucasian women were analyzed by array comparative genomic hybridization and by expression microarrays. Array comparative genomic hybridization data were analyzed using hierarchical clustering and supervised age cohort comparisons. Expression microarray data were analyzed using hierarchical clustering and gene set enrichment analysis; differential gene expression was also determined by conditional permutation, and an age signature was derived using prediction analysis of microarrays. Results Hierarchical clustering of genome-wide copy-number changes in 71 ER-positive DNA samples (27 younger women, 44 older women) demonstrated two age-independent genotypes; one with few genomic changes other than 1q gain/16q loss, and another with amplifications and low-level gains/losses. Age cohort comparisons showed no significant differences in total or site-specific genomic breaks and amplicon frequencies. Hierarchical clustering of 5.1 K genes variably expressed in 101 ER-positive RNA samples (53 younger women, 48 older women) identified six transcriptome subtypes with an apparent age bias (P < 0.05). Samples with higher expression of a poor outcome-associated proliferation signature were predominantly (65%) younger cases. Supervised analysis identified cancer-associated genes differentially expressed between the cohorts; with younger cases expressing more cell cycle genes and more than threefold higher levels of the growth factor amphiregulin (AREG), and with older cases expressing higher levels of four different homeobox (HOX) genes in addition to ER (ESR1). An age signature validated against two other independent breast cancer datasets proved to have >80% accuracy in discerning younger from older ER-positive breast cancer cases with characteristic differences in AREG and ESR1 expression. Conclusion These findings suggest that epigenetic transcriptome changes, more than genotypic variation, account for age-associated differences in sporadic breast cancer incidence and prognosis.
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Affiliation(s)
- Christina Yau
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA
| | - Vita Fedele
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
| | - Ritu Roydasgupta
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
| | - Jane Fridlyand
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
| | - Alan Hubbard
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA
| | - Joe W Gray
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
| | - Karen Chew
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
| | - Shanaz H Dairkee
- California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA 94107, USA
| | - Dan H Moore
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
- California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA 94107, USA
| | | | - Stefania Tommasi
- National Cancer Institute – Bari, via Amendola 209, 70126 Bari, Italy
| | - Angelo Paradiso
- National Cancer Institute – Bari, via Amendola 209, 70126 Bari, Italy
| | - Donna G Albertson
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
| | - Christopher C Benz
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA
- University of California Comprehensive Cancer Center, 2340 Sutter Street, University of California, San Francisco, CA 94143, USA
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183
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Borlon C, Weemaels G, Godard P, Debacq-Chainiaux F, Lemaire P, Deroanne C, Toussaint O. Expression profiling of senescent-associated genes in human dermis from young and old donors. Proof-of-concept study. Biogerontology 2008; 9:197-208. [PMID: 18270802 DOI: 10.1007/s10522-008-9127-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 01/29/2008] [Indexed: 11/26/2022]
Abstract
It is often described that it is difficult to really discriminate the cause of intrinsic skin aging. The aim of this study was to compare the profiles of expression of senescence-associated genes in biopsies of dermis from young and old human donors. TGF-beta1 was up-regulated in the dermis of old donors as well as the TGF-beta1-regulated genes. The anti-oxidant enzymes Selenium-dependent Glutathione peroxidase and Glutatione S-Transferase Theta 1 were also up-regulated in old dermis as well as Tumor Necrosis Factor Receptor Superfamily 1A. None of these genes had altered expression level in skin fibroblasts embedded in a collagen matrix and exposed to sublethal doses of UVB, suggesting their involvement in intrinsic aging. This study represents a proof-of-concept of larger whole transcriptome studies where all avenues should be used to subtract changes in gene expression due to extrinsic aging from changes potentially due to intrinsic aging.
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Affiliation(s)
- Céline Borlon
- Research Unit on Cellular Biology (URBC), Department of Biology, Faculty of Sciences, University of Namur (FUNDP), Rue de Bruxelles, 61, 5000 Namur, Belgium
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184
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Passtoors WM, Beekman M, Gunn D, Boer JM, Heijmans BT, Westendorp RGJ, Zwaan BJ, Slagboom PE. Genomic studies in ageing research: the need to integrate genetic and gene expression approaches. J Intern Med 2008; 263:153-66. [PMID: 18226093 DOI: 10.1111/j.1365-2796.2007.01904.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Genome-wide and hypothesis-based approaches to the study of ageing and longevity have been dominated by genetic investigations. To identify essential mechanisms of a complex trait such as ageing in higher species, a holistic understanding of interacting pathways is required. More information on such interactions is expected to be obtained from global gene expression analysis if combined with genetic studies. Genetic sequence variation often provides a functional gene marker for the trait, whereas a gene expression profile may provide a quantitative biomarker representing complex cellular pathway interactions contributing to the trait. Thus far, gene expression studies have associated multiple pathways to ageing including mitochondrial electron transport and the oxidative stress response. However, most of the studies are underpowered to detect small age-changes. A systematic survey of gene expression changes as a function of age in human individuals and animal models is lacking. Well designed gene expression studies, especially at the level of biological processes, will provide hypotheses on gene-environmental interactions determining biological ageing rate. Cross-sectional studies monitoring the profile as a chronological marker of ageing must be integrated with prospective studies indicating which profiles represent biomarkers preceding and predicting physiological decline and mortality. New study designs such as the Leiden Longevity Study, including two generations of subjects from longevity families, aim to achieve these combined approaches.
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Affiliation(s)
- W M Passtoors
- Section of Molecular Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
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185
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Lin JM, Wan L, Tsai YY, Lin HJ, Tsai Y, Lee CC, Tsai CH, Tsai FJ, Tseng SH. HTRA1 polymorphism in dry and wet age-related macular degeneration. Retina 2008; 28:309-13. [PMID: 18301036 DOI: 10.1097/iae.0b013e31814cef3a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate HTRA1 polymorphisms in unrelated Taiwan Chinese patients with age-related macular degeneration (AMD) and control subjects without AMD. METHODS A total of 95 unrelated Taiwan Chinese patients with AMD and 90 age- and sex-matched control subjects were enrolled in the study. Genomic DNA was prepared from peripheral blood obtained from all patients with AMD and control subjects. Polymerase chain reactions were used to analyze two HTRA1 single-nucleotide polymorphisms (rs11200638 [G/A] and rs10490924 [G/T]). RESULTS Of the 95 participants with AMD, dry AMD was diagnosed in 52 patients and wet AMD in 43 patients. Both rs11200638 (G/A) and rs10490924 (G/T) were significantly associated with all AMD (rs11200638: P = 6.7 x 10(-7) for an additive allele-dosage model, OR(het) = 1.97 [0.81, 4.81], OR(hom) = 8.59 [3.28, 22.49], A allele: 73% in all AMD versus 47% in controls; rs10490924: P = 9.2 x 10(-6), OR(het) = 1.86 [0.79, 4.35], OR(hom) = 5.08 [2.21, 11.70], T allele: 73% in all AMD versus 50% in controls). In terms of significance of association, rs11200638 was the most significantly associated variant. Subtype analysis including dry and wet AMD also revealed similar results. Haplotype analysis demonstrated that AT was significantly associated with wet and all AMD (P = 0.011 and 0.004, respectively), whereas GG was significantly associated with the control group when compared with all AMD (P = 0.035). CONCLUSIONS The study demonstrated that both single-nucleotide polymorphisms were significantly associated with dry and wet AMD and rs11200638 was the most significantly associated variant in a Taiwan Chinese population.
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Affiliation(s)
- Jane-Ming Lin
- Department of Ophthalmology, China Medical University Hospital, Taichung, Taiwan
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186
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Abstract
FOXM1 is a typical proliferation-associated transcription factor: it stimulates proliferation by promoting S-phase entry as well as M-phase entry and is involved in proper execution of mitosis. Accordingly, FOXM1 regulates genes that control G1/S-transition, S-phase progression, G2/M-transition and M-phase progression. Consistently, its expression and its activity are antagonistically regulated by many important proliferation and anti-proliferation signals. Furthermore, FOXM1 is implicated in tumorigenesis and contributes to both tumor initiation and progression. In addition to its function as a conventional transcription factor, FOXM1 transactivates the human c-myc P1 and P2 promoters directly via their TATA-boxes by a new transactivation mechanism, which it also employs for transactivation of the human c-fos, hsp70 and histone H2B/a promoters. This review summarizes the current knowledge on FOXM1, in particular its two different transactivation mechanisms, the regulation of its transcriptional activity by proliferation versus anti-proliferation signals and its function in normal cell cycle progression and tumorigenesis.
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187
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Impact of aging on the biology of breast cancer. Crit Rev Oncol Hematol 2007; 66:65-74. [PMID: 17949989 DOI: 10.1016/j.critrevonc.2007.09.001] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 08/31/2007] [Accepted: 09/05/2007] [Indexed: 12/30/2022] Open
Abstract
Breast cancer is a heterogeneous malignancy; its age-specific incidence profile rises exponentially until menopause and increases more slowly thereafter, reflecting the superimposition of early-onset and late-onset breast cancer rates. While early-onset breast cancers largely represent inherited or early life transforming effects on immature mammary epithelium, late-onset breast cancers likely follow extended exposures to promoting stimuli of susceptible epithelium that has failed to age normally. Among stimuli thought to promote late-onset breast tumorigenesis are the altered extracellular matrix and secreted products of senescent fibroblasts; however, the extent to which these senescent influences exist within the aging breast remains unknown. Clinical observations and biomarker studies indicate that late-onset breast cancers grow more slowly and are biologically less aggressive than early-onset breast cancers, even when controlled for hormone receptor (e.g. estrogen receptor, ER) and growth factor receptor (e.g. HER2) expression, supporting the conclusion that the biology of breast cancer is age-dependent.
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188
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He D, Zhou D, Zhou Y. Identifying transcription factor targets using enhanced Bayesian classifier. Comput Biol Chem 2007; 31:355-60. [PMID: 17890157 DOI: 10.1016/j.compbiolchem.2007.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 08/14/2007] [Accepted: 08/14/2007] [Indexed: 11/23/2022]
Abstract
Finding transcription factors (TFs) to their target genes (TGs) is the first step to understand the transcriptional regulatory networks. Here we present a method which uses an enhanced Bayesian classifier to predict the TF-TG pairs in time-course expression data. Different from previous prediction models, the gene expression data is encoded by discrete values and the temporal feature is used in the enhanced Bayesian classifier. The enhanced Bayesian classifier is trained and tested on two groups of positive and negative samples by three-fold cross-validation and compared with other methods. As the prediction result is improved obviously, the enhanced Bayesian classifier represents a new perspective on studying the regulation relationships from gene expression data. Further more, a data selection method which focus on 'active' TFs is proposed, suggesting a new approach on selecting effective time-course expression data.
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Affiliation(s)
- Dong He
- Hubei Bioinformatics and Molecular Imaging Key Laboratory, Huazhong University of Science and Technology, Wuhan 430074, China
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189
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Vernace VA, Schmidt-Glenewinkel T, Figueiredo-Pereira ME. Aging and regulated protein degradation: who has the UPPer hand? Aging Cell 2007; 6:599-606. [PMID: 17681036 PMCID: PMC3464091 DOI: 10.1111/j.1474-9726.2007.00329.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In all cells, protein degradation is a constant, ongoing process that is critical for cell survival and repair. The ubiquitin/proteasome pathway (UPP) is the major proteolytic pathway that degrades intracellular proteins in a regulated manner. It plays critical roles in many cellular processes and diseases. Disruption of the UPP is particularly relevant to pathophysiological conditions that provoke the accumulation of aberrant proteins, such as in aging as well as in a variety of neurodegenerative disorders including Alzheimer's and Parkinson's diseases. For unknown reasons, most of these neurodegenerative disorders that include familial and sporadic cases exhibit a late onset. It is possible that these neurodegenerative conditions exhibit a late onset because proteasome activity decreases with aging. Aging-dependent impairment in proteolysis mediated by the proteasome may have profound ramifications for cell viability. It can lead to the accumulation of modified, potentially toxic proteins in cells and can cause cell injury or premature cell death by apoptosis or necrosis. While it is accepted that aging affects UPP function, the question is why does aging cause a decline in regulated protein degradation by the UPP? Herein, we review some of the properties of the UPP and mechanisms mediating its age-dependent impairment. We also discuss the relevance of these findings leading to a model that proposes that UPP dysfunction may be one of the milestones of aging.
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Affiliation(s)
- Vita A Vernace
- Department of Biological Sciences, Hunter College of the City University of New York, New York, NY 10021, USA
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190
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Chevanne M, Calia C, Zampieri M, Cecchinelli B, Caldini R, Monti D, Bucci L, Franceschi C, Caiafa P. Oxidative DNA damage repair and parp 1 and parp 2 expression in Epstein-Barr virus-immortalized B lymphocyte cells from young subjects, old subjects, and centenarians. Rejuvenation Res 2007; 10:191-204. [PMID: 17518695 DOI: 10.1089/rej.2006.0514] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Oxidative DNA damage has been implicated in the aging process and in some of its features such as telomere shortening and replicative senescence. Poly(ADP-ribosyl)ation is involved in many molecular and cellular processes, including DNA damage detection and repair, chromatin modification, transcription, and cell death pathways. We decided to examine the behavior of poly(ADP-ribosyl)ation in centenarians, i.e., those subjects who represent the best example of longevity having reached a very advanced age avoiding the main age-associated diseases. In this study we investigated the relationship between DNA repair capacity and poly(ADP-ribose) polymerase activity in Epstein-Barr virus-immortalized B lymphocyte cell lines from subjects of three different groups of age, including centenarians. Our data show that cells from centenarians have characteristics typical of cells from young people both in their capability of priming the mechanism of repair after H(2)O(2) sublethal oxidative damage and in poly(ADP-ribosyl)ation capacity, while in cells from old subjects these phenomena are delayed or decreased. Moreover, cells from old subjects show a constitutive expression level of both parp 1 and parp 2 genes reduced by a half, together with a reduced presence of modified PARP 1 and other poly(ADP-ribosyl)ated chromatin proteins in comparison to cells from young subjects and centenarians. Our data support the hypothesis that this epigenetic modification is an important regulator of the aging process in humans and it appears to be rather preserved in healthy centenarians, the best example of successful aging.
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Affiliation(s)
- Marta Chevanne
- Department of Experimental Pathology and Oncology, University of Florence, Italy
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191
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Iida K, Nishimura I. Gene expression profiling by DNA microarray technology. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 2007; 13:35-50. [PMID: 12097236 DOI: 10.1177/154411130201300105] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Methods in molecular and genetic biology have provided important clues to elucidate the complex mechanisms of oral and craniofacial development and pathogenesis of diseases. It has become increasingly clear that a biological phenotype is a result of multiple factors involving a large number of regulatory genes, while a single nucleotide mutation can cause various degrees of oral and craniofacial abnormalities. These oral and craniofacial problems often present a challenge to the molecular screening process. Recent advances in microarray-based technologies allow for large-scale gene expression analysis in a single experiment, which have been applied to genome-wide assays, mutational analysis, drug discovery, developmental biology, and molecular analysis of various diseases. This review introduces the basic principle and some modifications of techniques and materials used in microarray technology, as well as currently available microarray data analysis strategies. Microarray technology can be applied to the soon-to-be-available human genome database and will be a powerful research tool for those inquiring into specific problems associated with oral and craniofacial biology.
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Affiliation(s)
- Keisuke Iida
- The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, California 90095-1668, USA
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192
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Olcay L, Yetgin S, Okur H, Erdemli E. Rapid cell senescence and apoptosis in lymphocytes and granulocytes and absence of GM-CSF receptor in congenital dysgranulopoietic neutropenia. Leuk Res 2007; 32:235-42. [PMID: 17686517 DOI: 10.1016/j.leukres.2007.06.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2007] [Revised: 06/20/2007] [Accepted: 06/22/2007] [Indexed: 11/18/2022]
Abstract
A girl with congenital dysgranulopoietic neutropenia (CDN) and her non-neutropenic mother with aphthae (A) were investigated. Apoptosis in lymphocytes and granulocytes of both patients (mother A+) were documented by high annexin and electron microscopic morphology. CD11b/CD18 of the daughter's granulocytes ranged between low to normal while that of the mother changed between very low to high levels through A(-) to A(+) periods. In both patients, CD11b/CD18 on lymphocytes were high; GM-CSF receptor was negative; CD4-/CD8- lymphocytes were high and the leukocytes which showed abnormal cell cycle were stained by senescence associated beta-galactosidase. We think that increased apoptosis and rapid cell senescence of leukocytes underlies the pathophysiology of CDN.
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Affiliation(s)
- Lale Olcay
- Dr AY Ankara Oncology Research and Education Hospital, Unit of Pediatric Hematology, Demetevler, Ankara, Turkey.
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193
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Kalamajski S, Oldberg Å. Fibromodulin binds collagen type I via Glu-353 and Lys-355 in leucine-rich repeat 11. J Biol Chem 2007; 282:26740-26745. [PMID: 17623650 DOI: 10.1074/jbc.m704026200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fibromodulin belongs to the small leucine-rich repeat proteoglycan family, interacts with collagen type I, and controls collagen fibrillogenesis and assembly. Here, we show that a major fibromodulin-binding site for collagen type I is located in leucine-rich repeat 11 in the C terminus of the leucine-rich repeat domain. We identified Glu-353 and Lys-355 in repeat 11 as essential for binding, and the synthetic peptide RLDGNEIKR, including Glu-353 and Lys-355, inhibits the binding of fibromodulin to collagen in vitro. Fibromodulin and lumican compete for the same binding region on collagen, and fibromodulin can inhibit the binding of lumican to collagen type I. However, the peptide RLDGNEIKR does not inhibit the binding of lumican to collagen, suggesting separate but closely situated fibromodulin- and lumican-binding sites in collagen. The collagen-binding Glu-353 and Lys-355 residues in fibromodulin are exposed on the exterior of the beta-sheet-loop structure of the leucine-rich repeat, which resembles the location of interacting residues in other leucine-rich repeat proteins, e.g. decorin.
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Affiliation(s)
- Sebastian Kalamajski
- Department of Experimental Medical Science, University of Lund, SE-221 84 Lund, Sweden
| | - Åke Oldberg
- Department of Experimental Medical Science, University of Lund, SE-221 84 Lund, Sweden.
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194
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Abstract
In the past several years, remarkable progress has been made in the understanding of the mechanisms of premature aging. These rare, genetic conditions offer valuable insights into the normal aging process and the complex biology of cardiovascular disease. Many of these advances have been made in the most dramatic of these disorders, Hutchinson–Gilford progeria syndrome. Although characterized by features of normal aging such as alopecia, skin wrinkling, and osteoporosis, patients with Hutchinson–Gilford progeria syndrome are affected by accelerated, premature arteriosclerotic disease that leads to heart attacks and strokes at a mean age of 13 years. In this review, we highlight recent advances in the biology of premature aging uncovered in Hutchinson–Gilford progeria syndrome and other accelerated aging syndromes, advances that provide insight into the mechanisms of cardiovascular diseases ranging from atherosclerosis to arrhythmias.
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Affiliation(s)
- Brian C Capell
- Genome Technology Branch, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892-2486, USA
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195
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Yurov YB, Iourov IY, Vorsanova SG, Liehr T, Kolotii AD, Kutsev SI, Pellestor F, Beresheva AK, Demidova IA, Kravets VS, Monakhov VV, Soloviev IV. Aneuploidy and confined chromosomal mosaicism in the developing human brain. PLoS One 2007; 2:e558. [PMID: 17593959 PMCID: PMC1891435 DOI: 10.1371/journal.pone.0000558] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 05/28/2007] [Indexed: 11/18/2022] Open
Abstract
Background Understanding the mechanisms underlying generation of neuronal variability and complexity remains the central challenge for neuroscience. Structural variation in the neuronal genome is likely to be one important mechanism for neuronal diversity and brain diseases. Large-scale genomic variations due to loss or gain of whole chromosomes (aneuploidy) have been described in cells of the normal and diseased human brain, which are generated from neural stem cells during intrauterine period of life. However, the incidence of aneuploidy in the developing human brain and its impact on the brain development and function are obscure. Methodology/Principal Findings To address genomic variation during development we surveyed aneuploidy/polyploidy in the human fetal tissues by advanced molecular-cytogenetic techniques at the single-cell level. Here we show that the human developing brain has mosaic nature, being composed of euploid and aneuploid neural cells. Studying over 600,000 neural cells, we have determined the average aneuploidy frequency as 1.25–1.45% per chromosome, with the overall percentage of aneuploidy tending to approach 30–35%. Furthermore, we found that mosaic aneuploidy can be exclusively confined to the brain. Conclusions/Significance Our data indicates aneuploidization to be an additional pathological mechanism for neuronal genome diversification. These findings highlight the involvement of aneuploidy in the human brain development and suggest an unexpected link between developmental chromosomal instability, intercellural/intertissular genome diversity and human brain diseases.
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Affiliation(s)
- Yuri B Yurov
- National Research Center of Mental Health, Russian Academy of Medical Sciences, Moscow, Russia; Institute of Pediatrics and Children Surgery, Roszdrav, Moscow, Russia.
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196
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Pena AN, Pereira-Smith OM. The role of the MORF/MRG family of genes in cell growth, differentiation, DNA repair, and thereby aging. Ann N Y Acad Sci 2007; 1100:299-305. [PMID: 17460191 DOI: 10.1196/annals.1395.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The discovery that replicative cellular senescence is a dominant phenotype over immortality led to the discovery that there are at least four unique genetic subgroups of immortal cell lines that use distinct mechanistic pathways to evade cell cycle exit. Study of one of these genetic complementation groups demonstrated that one gene, MORF4, possessed the ability to induce senescence in group B cell lines. The MRG family of genes, of which MORF4 is a member, has since proven important for cellular aging, proliferation, positive and negative transcriptional regulation, and DNA damage repair. MRG15, the evolutionary ancestor of the family, is highly conserved in yeast, C. elegans, drosophila, plants, and mammals and has been implicated in chromatin remodeling in these species. Our proteomics studies have found that MRG15 is unique among mammalian genes in that it associates with both histone deacetylases and histone acetyl transferase complexes, and thus potentially plays a role in both transcriptional silencing and activation. Its knockout in mice is embryonic lethal, resulting in improper organogenesis, as well as cell proliferation and DNA damage repair defects. Future study of these genes will help clarify the role of chromatin remodeling in aging, cellular proliferation, and DNA damage repair.
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Affiliation(s)
- Andreana N Pena
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, STCBM Building, 15355 Lambda Drive, San Antonio, TX 78245-3207, USA.
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197
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Makrantonaki E, Zouboulis CC. William J. Cunliffe Scientific Awards. Characteristics and pathomechanisms of endogenously aged skin. Dermatology 2007; 214:352-60. [PMID: 17460411 DOI: 10.1159/000100890] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The skin, being in direct contact with several environmental factors (e.g. UV irradiation), does not only undergo endogenous aging, which has to do with the 'biological clock' of the skin cells per se, but also exogenous aging. While exogenous skin aging has been extensively studied, the pathomechanisms of endogenous skin aging remain far less clear. Endogenous skin aging reflects reduction processes, which are common in internal organs. These processes include cellular senescence and decreased proliferative capacity, decrease in cellular DNA repair capacity and chromosomal abnormalities, loss of telomeres, point mutations of extranuclear mtDNA, oxidative stress and gene mutations. As a consequence, aged skin in nonexposed areas shows typical characteristics including fine wrinkles, dryness, sallowness and loss of elasticity. Recent data have illustrated that lack of hormones occurring with age may also contribute to the aging phenotype. Improvement of epidermal skin moisture, elasticity and skin thickness, enhanced production of surface lipids, reduction of wrinkle depth, restoration of collagen fibers and increase of the collagen III/I ratio have been reported after hormone replacement therapy or local estrogen treatment in postmenopausal women. Furthermore, an in vitro model of endogenous skin aging consisting of human SZ95 sebocytes which were incubated under a hormone-substituted environment illustrated that hormones at age- and sex-specific levels were able to alter the development of cells by regulating their transcriptome. In conclusion, among other factors the hormone environment plays a distinct role in the generation of aged skin.
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Affiliation(s)
- Evgenia Makrantonaki
- Laboratory for Biogerontology, Dermato-Pharmacology and Dermato-Endocrinology, Institute of Clinical Pharmacology and Toxicology, Charité Universitatsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany
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198
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Meaburn KJ, Cabuy E, Bonne G, Levy N, Morris GE, Novelli G, Kill IR, Bridger JM. Primary laminopathy fibroblasts display altered genome organization and apoptosis. Aging Cell 2007; 6:139-53. [PMID: 17274801 DOI: 10.1111/j.1474-9726.2007.00270.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
A number of diseases associated with specific tissue degeneration and premature aging have mutations in the nuclear envelope proteins A-type lamins or emerin. Those diseases with A-type lamin mutation are inclusively termed laminopathies. Due to various hypothetical roles of nuclear envelope proteins in genome function we investigated whether alterations to normal genomic behaviour are apparent in cells with mutations in A-type lamins and emerin. Even though the distributions of these proteins in proliferating laminopathy fibroblasts appear normal, there is abnormal nuclear positioning of both chromosome 18 and 13 territories, from the nuclear periphery to the interior. This genomic organization mimics that found in normal nonproliferating quiescent or senescent cells. This finding is supported by distributions of modified pRb in the laminopathy cells. All laminopathy cell lines tested and an X-linked Emery-Dreifuss muscular dystrophy cell line also demonstrate increased incidences of apoptosis. The most extreme cases of apoptosis occur in cells derived from diseases with mutations in the tail region of the LMNA gene, such as Dunningan-type familial partial lipodystrophy and mandibuloacral dysplasia, and this correlates with a significant level of micronucleation in these cells.
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Affiliation(s)
- Karen J Meaburn
- Laboratory of Nuclear and Genomic Health, Division of Biosciences, School of Health Sciences and Social Care, Brunel University, Uxbridge, Middlesex UB8 3PH, UK
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199
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Cao K, Capell BC, Erdos MR, Djabali K, Collins FS. A lamin A protein isoform overexpressed in Hutchinson-Gilford progeria syndrome interferes with mitosis in progeria and normal cells. Proc Natl Acad Sci U S A 2007; 104:4949-54. [PMID: 17360355 PMCID: PMC1821129 DOI: 10.1073/pnas.0611640104] [Citation(s) in RCA: 193] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2006] [Indexed: 11/18/2022] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by dramatic premature aging. Classic HGPS is caused by a de novo point mutation in exon 11 (residue 1824, C --> T) of the LMNA gene, activating a cryptic splice donor and resulting in a mutant lamin A (LA) protein termed "progerin/LADelta50" that lacks the normal cleavage site to remove a C-terminal farnesyl group. During interphase, irreversibly farnesylated progerin/LADelta50 anchors to the nuclear membrane and causes characteristic nuclear blebbing. Progerin/LADelta50's localization and behavior during mitosis, however, are completely unknown. Here, we report that progerin/LADelta50 mislocalizes into insoluble cytoplasmic aggregates and membranes during mitosis and causes abnormal chromosome segregation and binucleation. These phenotypes are largely rescued with either farnesyltransferase inhibitors or a farnesylation-incompetent mutant progerin/LADelta50. Furthermore, we demonstrate that small amounts of progerin/LADelta50 exist in normal fibroblasts, and a significant percentage of these progerin/LADelta50-expressing normal cells are binucleated, implicating progerin/LADelta50 as causing similar mitotic defects in the normal aging process. Our findings present evidence of mitotic abnormality in HGPS and may shed light on the general phenomenon of aging.
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Affiliation(s)
- Kan Cao
- *Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Brian C. Capell
- *Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Michael R. Erdos
- *Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892; and
| | - Karima Djabali
- Department of Dermatology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Francis S. Collins
- *Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892; and
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200
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Dechat T, Shimi T, Adam SA, Rusinol AE, Andres DA, Spielmann HP, Sinensky MS, Goldman RD. Alterations in mitosis and cell cycle progression caused by a mutant lamin A known to accelerate human aging. Proc Natl Acad Sci U S A 2007; 104:4955-60. [PMID: 17360326 PMCID: PMC1829246 DOI: 10.1073/pnas.0700854104] [Citation(s) in RCA: 220] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Mutations in the gene encoding nuclear lamin A (LA) cause the premature aging disease Hutchinson-Gilford Progeria Syndrome. The most common of these mutations results in the expression of a mutant LA, with a 50-aa deletion within its C terminus. In this study, we demonstrate that this deletion leads to a stable farnesylation and carboxymethylation of the mutant LA (LADelta50/progerin). These modifications cause an abnormal association of LADelta50/progerin with membranes during mitosis, which delays the onset and progression of cytokinesis. Furthermore, we demonstrate that the targeting of nuclear envelope/lamina components into daughter cell nuclei in early G(1) is impaired in cells expressing LADelta50/progerin. The mutant LA also appears to be responsible for defects in the retinoblastoma protein-mediated transition into S-phase, most likely by inhibiting the hyperphosphorylation of retinoblastoma protein by cyclin D1/cdk4. These results provide insights into the mechanisms responsible for premature aging and also shed light on the role of lamins in the normal process of human aging.
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Affiliation(s)
- Thomas Dechat
- *Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611
| | - Takeshi Shimi
- *Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611
| | - Stephen A. Adam
- *Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611
| | - Antonio E. Rusinol
- Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Box 70581,Johnson City, TN 37614; and
| | | | - H. Peter Spielmann
- Departments of Molecular and Cellular Biochemistry and
- Chemistry and
- Kentucky Center for Structural Biology, University of Kentucky, 741 South Limestone, Lexington, KY 40536
| | - Michael S. Sinensky
- Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Box 70581,Johnson City, TN 37614; and
| | - Robert D. Goldman
- *Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, 303 East Chicago Avenue, Chicago, IL 60611
- To whom correspondence should be addressed. E-mail:
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