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Shilovsky GA. Calculating Aging: Analysis of Survival Curves in the Norm and Pathology, Fluctuations in Mortality Dynamics, Characteristics of Lifespan Distribution, and Indicators of Lifespan Variation. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:371-376. [PMID: 38622103 DOI: 10.1134/s0006297924020159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 11/24/2023] [Accepted: 12/29/2023] [Indexed: 04/17/2024]
Abstract
The article describes the history of studies of survival data carried out at the Research Institute of Physico-Chemical Biology under the leadership of Academician V. P. Skulachev from 1970s until present, with special emphasis on the last decade. The use of accelerated failure time (AFT) model and analysis of coefficient of variation of lifespan (CVLS) in addition to the Gompertz methods of analysis, allows to assess survival curves for the presence of temporal scaling (i.e., manifestation of accelerated aging), without changing the shape of survival curve with the same coefficient of variation. A modification of the AFT model that uses temporal scaling as the null hypothesis made it possible to distinguish between the quantitative and qualitative differences in the dynamics of aging. It was also shown that it is possible to compare the data on the survival of species characterized by the survival curves of the original shape (i.e., "flat" curves without a pronounced increase in the probability of death with age typical of slowly aging species), when considering the distribution of lifespan as a statistical random variable and comparing parameters of such distribution. Thus, it was demonstrated that the higher impact of mortality caused by external factors (background mortality) in addition to the age-dependent mortality, the higher the disorder of mortality values and the greater its difference from the calculated value characteristic of developed countries (15-20%). For comparison, CVLS for the Paraguayan Ache Indians is 100% (57% if we exclude prepuberty individuals as suggested by Jones et al.). According to Skulachev, the next step is considering mortality fluctuations as a measure for the disorder of survival data. Visual evaluation of survival curves can already provide important data for subsequent analysis. Thus, Sokolov and Severin [1] found that mutations have different effects on the shape of survival curves. Type I survival curves generally retains their standard convex rectangular shape, while type II curves demonstrate a sharp increase in the mortality which makes them similar to a concave exponential curve with a stably high mortality rate. It is noteworthy that despite these differences, mutations in groups I and II are of a similar nature. They are associated (i) with "DNA metabolism" (DNA repair, transcription, and replication); (ii) protection against oxidative stress, associated with the activity of the transcription factor Nrf2, and (iii) regulation of proliferation, and (or these categories may overlap). However, these different mutations appear to produce the same result at the organismal level, namely, accelerated aging according to the Gompertz's law. This might be explained by the fact that all these mutations, each in its own unique way, either reduce the lifespan of cells or accelerate their transition to the senescent state, which supports the concept of Skulachev on the existence of multiple pathways of aging (chronic phenoptosis).
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Affiliation(s)
- Gregory A Shilovsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127051, Russia
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2
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Sokolov SS, Severin FF. Two Types of Survival Curves of Different Lines of Progeric Mice. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:367-370. [PMID: 38622102 DOI: 10.1134/s0006297924020147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/02/2023] [Accepted: 12/29/2023] [Indexed: 04/17/2024]
Abstract
For most of their lifespan, the probability of death for many animal species increases with age. Gompertz law states that this increase is exponential. In this work, we have compared previously published data on the survival kinetics of different lines of progeric mice. Visual analysis showed that in six lines of these rapidly aging mutants, the probability of death did not strictly depend on age. In contrast, ten lines of progeric mice have survival curves similar to those of the control animals, that is, in agreement with Gompertz law, similar to the shape of an exponential curve upside down. Interestingly, these ten mutations cause completely different cell malfunctions. We speculate that what these mutations have in common is a reduction in the lifespan of cells and/or an acceleration of the transition to the state of cell senescence. Thus, our analysis, similar to the conclusions of many previously published works, indicates that the aging of an organism is a consequence of the aging of individual cells.
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Affiliation(s)
- Svyatoslav S Sokolov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Fedor F Severin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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3
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Yoon I, Kim U, Choi J, Kim S. Disease association and therapeutic routes of aminoacyl-tRNA synthetases. Trends Mol Med 2024; 30:89-105. [PMID: 37949787 DOI: 10.1016/j.molmed.2023.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 11/12/2023]
Abstract
Aminoacyl-tRNA synthetases (ARSs) are enzymes that catalyze the ligation of amino acids to tRNAs for translation. Beyond their traditional role in translation, ARSs have acquired regulatory functions in various biological processes (epi-translational functions). With their dual-edged activities, aberrant expression, secretion, and mutations of ARSs are associated with human diseases, including cancer, autoimmune diseases, and neurological diseases. The increasing numbers of newly unveiled activities and disease associations of ARSs have spurred interest in novel drug development, targeting disease-related catalytic and noncatalytic activities of ARSs as well as harnessing ARSs as sources for biological therapeutics. This review speculates how the translational and epi-translational activities of ARSs can be related and describes how their activities can be linked to diseases and drug discovery.
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Affiliation(s)
- Ina Yoon
- Institute for Artificial Intelligence and Biomedical Research, Medicinal Bioconvergence Research Center, College of Pharmacy, Yonsei University, Incheon 21983, Republic of Korea
| | - Uijoo Kim
- Institute for Artificial Intelligence and Biomedical Research, Medicinal Bioconvergence Research Center, College of Pharmacy, Yonsei University, Incheon 21983, Republic of Korea
| | - Jaeyoung Choi
- Institute for Artificial Intelligence and Biomedical Research, Medicinal Bioconvergence Research Center, College of Pharmacy, Yonsei University, Incheon 21983, Republic of Korea
| | - Sunghoon Kim
- Institute for Artificial Intelligence and Biomedical Research, Medicinal Bioconvergence Research Center, College of Pharmacy, Yonsei University, Incheon 21983, Republic of Korea; College of Medicine, Gangnam Severance Hospital, Yonsei University, Seoul 06273, Republic of Korea; Institute for Convergence Research and Education in Advanced Technology, Yonsei University, Incheon 21983, Republic of Korea.
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4
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Buchwalter A. Intermediate, but not average: The unusual lives of the nuclear lamin proteins. Curr Opin Cell Biol 2023; 84:102220. [PMID: 37619289 DOI: 10.1016/j.ceb.2023.102220] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/26/2023]
Abstract
The nuclear lamins are polymeric intermediate filament proteins that scaffold the nucleus and organize the genome in nearly all eukaryotic cells. This review focuses on the dynamic regulation of lamin filaments through their biogenesis, assembly, disassembly, and degradation. The lamins are unusually long-lived proteins under homeostatic conditions, but their turnover can be induced in select contexts that are highlighted in this review. Finally, we discuss recent investigations into the influence of laminopathy-linked mutations on the assembly, folding, and stability of the nuclear lamins.
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Affiliation(s)
- Abigail Buchwalter
- Cardiovascular Research Institute and Department of Physiology, University of California, San Francisco, San Francisco, CA, USA; Chan Zuckerberg Biohub, San Francisco, CA, USA.
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5
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Waad Sadiq Z, Brioli A, Al-Abdulla R, Çetin G, Schütt J, Murua Escobar H, Krüger E, Ebstein F. Immunogenic cell death triggered by impaired deubiquitination in multiple myeloma relies on dysregulated type I interferon signaling. Front Immunol 2023; 14:982720. [PMID: 36936919 PMCID: PMC10018035 DOI: 10.3389/fimmu.2023.982720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
Introduction Proteasome inhibition is first line therapy in multiple myeloma (MM). The immunological potential of cell death triggered by defects of the ubiquitin-proteasome system (UPS) and subsequent perturbations of protein homeostasis is, however, less well defined. Methods In this paper, we applied the protein homeostasis disruptors bortezomib (BTZ), ONX0914, RA190 and PR619 to various MM cell lines and primary patient samples to investigate their ability to induce immunogenic cell death (ICD). Results Our data show that while BTZ treatment triggers sterile type I interferon (IFN) responses, exposure of the cells to ONX0914 or RA190 was mostly immunologically silent. Interestingly, inhibition of protein de-ubiquitination by PR619 was associated with the acquisition of a strong type I IFN gene signature which relied on key components of the unfolded protein and integrated stress responses including inositol-requiring enzyme 1 (IRE1), protein kinase R (PKR) and general control nonderepressible 2 (GCN2). The immunological relevance of blocking de-ubiquitination in MM was further reflected by the ability of PR619-induced apoptotic cells to facilitate dendritic cell (DC) maturation via type I IFN-dependent mechanisms. Conclusion Altogether, our findings identify de-ubiquitination inhibition as a promising strategy for inducing ICD of MM to expand current available treatments.
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Affiliation(s)
- Zeinab Waad Sadiq
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Annamaria Brioli
- Klinik und Poliklinik für Innere Medizin C, Universitätsmedizin Greifswald, Greifswald, Germany
- Klinik für Innere Medizin II, Universitätsklinikum Jena, Jena, Germany
| | - Ruba Al-Abdulla
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Gonca Çetin
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Jacqueline Schütt
- Klinik und Poliklinik für Innere Medizin C, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Hugo Murua Escobar
- Department of Medicine, Clinic III, Hematology, Oncology, Palliative Medicine, Rostock University Medical Center, Rostock, Germany
| | - Elke Krüger
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
| | - Frédéric Ebstein
- Institut für Medizinische Biochemie und Molekularbiologie (IMBM), Universitätsmedizin Greifswald, Greifswald, Germany
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6
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Ho JJD, Cunningham TA, Manara P, Coughlin CA, Arumov A, Roberts ER, Osteen A, Kumar P, Bilbao D, Krieger JR, Lee S, Schatz JH. Proteomics reveal cap-dependent translation inhibitors remodel the translation machinery and translatome. Cell Rep 2021; 37:109806. [PMID: 34644561 PMCID: PMC8558842 DOI: 10.1016/j.celrep.2021.109806] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/28/2021] [Accepted: 09/16/2021] [Indexed: 12/15/2022] Open
Abstract
Tactical disruption of protein synthesis is an attractive therapeutic strategy, with the first-in-class eIF4A-targeting compound zotatifin in clinical evaluation for cancer and COVID-19. The full cellular impact and mechanisms of these potent molecules are undefined at a proteomic level. Here, we report mass spectrometry analysis of translational reprogramming by rocaglates, cap-dependent initiation disruptors that include zotatifin. We find effects to be far more complex than simple “translational inhibition” as currently defined. Translatome analysis by TMT-pSILAC (tandem mass tag-pulse stable isotope labeling with amino acids in cell culture mass spectrometry) reveals myriad upregulated proteins that drive hitherto unrecognized cytotoxic mechanisms, including GEF-H1-mediated anti-survival RHOA/JNK activation. Surprisingly, these responses are not replicated by eIF4A silencing, indicating a broader translational adaptation than currently understood. Translation machinery analysis by MATRIX (mass spectrometry analysis of active translation factors using ribosome density fractionation and isotopic labeling experiments) identifies rocaglate-specific dependence on specific translation factors including eEF1ε1 that drive translatome remodeling. Our proteome-level interrogation reveals that the complete cellular response to these historical “translation inhibitors” is mediated by comprehensive translational landscape remodeling. Tactical protein synthesis inhibition is actively pursued as a cancer therapy that bypasses signaling redundancies limiting current strategies. Ho et al. show that rocaglates, first identified as inhibitors of eIF4A activity, globally reprogram cellular translation at both protein synthesis machinery and translatome levels, inducing cytotoxicity through anti-survival GEF-H1/RHOA/JNK signaling.
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Affiliation(s)
- J J David Ho
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Tyler A Cunningham
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Molecular and Cellular Pharmacology Graduate Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Paola Manara
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Caroline A Coughlin
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Medical Scientist Training Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Artavazd Arumov
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Sheila and David Fuente Graduate Program in Cancer Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Evan R Roberts
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ashanti Osteen
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Preet Kumar
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Daniel Bilbao
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Cancer Modeling Shared Resource, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | | | - Stephen Lee
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Division of Hematology, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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7
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Hwang BH, Kim E, Park EH, Kim CW, Lee KY, Kim JJ, Choo EH, Lim S, Choi IJ, Kim CJ, Ihm SH, Chang K. AIMP3 induces laminopathy and senescence of vascular smooth muscle cells by reducing lamin A expression and leads to vascular aging in vivo. Exp Gerontol 2021; 153:111483. [PMID: 34274427 DOI: 10.1016/j.exger.2021.111483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 06/26/2021] [Accepted: 07/13/2021] [Indexed: 11/17/2022]
Abstract
Aminoacyl-tRNA synthetase-interacting multifunctional protein 3 (AIMP3), a tumor suppressor, mediates a progeroid phenotype in mice by downregulating lamin A. We investigated whether AIMP3 induces laminopathy and senescence of human aortic smooth muscle cells (HASMCs) and is associated with vascular aging in mice and humans in line with decreased lamin A expression. Cellular senescence was evaluated after transfecting HASMCs with AIMP3. Molecular analyses of genes encoding AIMP3, lamin A, chemokine (C-C motif) ligand 2 (CCL2), and C-C chemokine receptor type 2 (CCR2) and histological comparisons of aortas were performed with mice at various ages (7 weeks, 5 months, 12 months, 24 months, and 32 months), AIMP3-transgenic mice, and human femoral arteries of cadavers. AIMP3-transfected HASMCs exhibited increased AIMP3 and senescence marker p16 protein expression and decreased lamin A protein expression in accordance with their disrupted nuclear morphology in histological analyses. AIMP3-transgenic mice displayed increased AIMP3 protein expression and decreased lamin A protein expression in aortas together with typical aging pathologies. Similar changes were observed in wild-type aging (24-month-old) mice but not in wild-type young (7-week-old) mice. In humans, AIMP3 and lamin A protein expression was higher and lower, respectively, in femoral arteries of elderly individuals than in those of their younger counterparts. This study found that AIMP3 overexpression in vitro decreased lamin A expression and induced nuclear laminopathy and cellular senescence. Similar findings were made in the vasculature of aging mice and elderly humans.
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Affiliation(s)
- Byung Hee Hwang
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Eunmin Kim
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Eun-Hye Park
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Chan Woo Kim
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kwan-Yong Lee
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jin-Jin Kim
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Eun Ho Choo
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sungmin Lim
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Gyeonggi-do, Republic of Korea
| | - Ik Jun Choi
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Republic of Korea
| | - Chan Joon Kim
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Uijeongbu St. Mary's Hospital, The Catholic University of Korea, Gyeonggi-do, Republic of Korea
| | - Sang-Hyun Ihm
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Bucheon St. Mary's Hospital, The Catholic University of Korea, Gyeonggi-do, Republic of Korea
| | - Kiyuk Chang
- Cardiovascular Research Institute for Intractable Disease, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Division of Cardiology, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea.
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8
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Ham S, Yun SP, Kim H, Kim D, Seo BA, Kim H, Shin JY, Dar MA, Lee GH, Lee YI, Kim D, Kim S, Kweon HS, Shin JH, Ko HS, Lee Y. Amyloid-like oligomerization of AIMP2 contributes to α-synuclein interaction and Lewy-like inclusion. Sci Transl Med 2021; 12:12/569/eaax0091. [PMID: 33177178 DOI: 10.1126/scitranslmed.aax0091] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/03/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022]
Abstract
Lewy bodies are pathological protein inclusions present in the brain of patients with Parkinson's disease (PD). These inclusions consist mainly of α-synuclein with associated proteins, such as parkin and its substrate aminoacyl transfer RNA synthetase complex-interacting multifunctional protein-2 (AIMP2). Although AIMP2 has been suggested to be toxic to dopamine neurons, its roles in α-synuclein aggregation and PD pathogenesis are largely unknown. Here, we found that AIMP2 exhibits a self-aggregating property. The AIMP2 aggregate serves as a seed to increase α-synuclein aggregation via specific and direct binding to the α-synuclein monomer. The coexpression of AIMP2 and α-synuclein in cell cultures and in vivo resulted in the rapid formation of α-synuclein aggregates with a corresponding increase in toxicity. Moreover, accumulated AIMP2 in mouse brain was largely redistributed to insoluble fractions, correlating with the α-synuclein pathology. Last, we found that α-synuclein preformed fibril (PFF) seeding, adult Parkin deletion, or oxidative stress triggered a redistribution of both AIMP2 and α-synuclein into insoluble fraction in cells and in vivo. Supporting the pathogenic role of AIMP2, AIMP2 knockdown ameliorated the α-synuclein aggregation and dopaminergic cell death in response to PFF or 6-hydroxydopamine treatment. Together, our results suggest that AIMP2 plays a pathological role in the aggregation of α-synuclein in mice. Because AIMP2 insolubility and coaggregation with α-synuclein have been seen in the PD Lewy body, targeting pathologic AIMP2 aggregation might be useful as a therapeutic strategy for neurodegenerative α-synucleinopathies.
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Affiliation(s)
- Sangwoo Ham
- Division of Pharmacology, Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Suwon 16419, Republic of Korea.,ToolGen Inc., Seoul 08501, Republic of Korea
| | - Seung Pil Yun
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hyojung Kim
- Division of Pharmacology, Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Suwon 16419, Republic of Korea
| | - Donghoon Kim
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bo Am Seo
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Heejeong Kim
- Division of Pharmacology, Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Suwon 16419, Republic of Korea
| | - Jeong-Yong Shin
- Division of Pharmacology, Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Suwon 16419, Republic of Korea
| | - Mohamad Aasif Dar
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gum Hwa Lee
- College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea
| | - Yun Il Lee
- Well Aging Research Center, DGIST, Daegu 42988, Republic of Korea.,Companion Diagnostics and Medical Technology Research Group, DGIST, Daegu 42988, Republic of Korea
| | - Doyeun Kim
- Medicinal Bioconvergence Research Center, Yonsei University, Incheon 21983, Republic of Korea.,College of Pharmacy and School of Medicine, Yonsei University, Incheon 21983, Republic of Korea
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center, Yonsei University, Incheon 21983, Republic of Korea.,College of Pharmacy and School of Medicine, Yonsei University, Incheon 21983, Republic of Korea
| | - Hee-Seok Kweon
- Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
| | - Joo-Ho Shin
- Division of Pharmacology, Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Suwon 16419, Republic of Korea
| | - Han Seok Ko
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. .,Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yunjong Lee
- Division of Pharmacology, Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute (SBRI), Suwon 16419, Republic of Korea.
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9
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Murray-Nerger LA, Cristea IM. Lamin post-translational modifications: emerging toggles of nuclear organization and function. Trends Biochem Sci 2021; 46:832-847. [PMID: 34148760 DOI: 10.1016/j.tibs.2021.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/03/2021] [Accepted: 05/18/2021] [Indexed: 01/03/2023]
Abstract
Nuclear lamins are ancient type V intermediate filaments with diverse functions that include maintaining nuclear shape, mechanosignaling, tethering and stabilizing chromatin, regulating gene expression, and contributing to cell cycle progression. Despite these numerous roles, an outstanding question has been how lamins are regulated. Accumulating work indicates that a range of lamin post-translational modifications (PTMs) control their functions both in homeostatic cells and in disease states such as progeria, muscular dystrophy, and viral infection. Here, we review the current knowledge of the diverse types of PTMs that regulate lamins in a site-specific manner. We highlight methods that can be used to characterize lamin PTMs whose functions are currently unknown and provide a perspective on the future of the lamin PTM field.
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Affiliation(s)
- Laura A Murray-Nerger
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544, USA.
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10
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Roles of tRNA metabolism in aging and lifespan. Cell Death Dis 2021; 12:548. [PMID: 34039958 PMCID: PMC8154886 DOI: 10.1038/s41419-021-03838-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/17/2022]
Abstract
Transfer RNAs (tRNAs) mainly function as adapter molecules that decode messenger RNAs (mRNAs) during protein translation by delivering amino acids to the ribosome. Traditionally, tRNAs are considered as housekeepers without additional functions. Nevertheless, it has become apparent from biological research that tRNAs are involved in various physiological and pathological processes. Aging is a form of gradual decline in physiological function that ultimately leads to increased vulnerability to multiple chronic diseases and death. Interestingly, tRNA metabolism is closely associated with aging and lifespan. In this review, we summarize the emerging roles of tRNA-associated metabolism, such as tRNA transcription, tRNA molecules, tRNA modifications, tRNA aminoacylation, and tRNA derivatives, in aging and lifespan, aiming to provide new ideas for developing therapeutics and ultimately extending lifespan in humans.
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11
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Potter ML, Hill WD, Isales CM, Hamrick MW, Fulzele S. MicroRNAs are critical regulators of senescence and aging in mesenchymal stem cells. Bone 2021; 142:115679. [PMID: 33022453 PMCID: PMC7901145 DOI: 10.1016/j.bone.2020.115679] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/16/2020] [Accepted: 07/28/2020] [Indexed: 01/10/2023]
Abstract
MicroRNAs (miRNAs) have recently come under scrutiny for their role in various age-related diseases. Similarly, cellular senescence has been linked to disease and aging. MicroRNAs and senescence likely play an intertwined role in driving these pathologic states. In this review, we present the connection between these two drivers of age-related disease concerning mesenchymal stem cells (MSCs). First, we summarize key miRNAs that are differentially expressed in MSCs and other musculoskeletal lineage cells during senescence and aging. Additionally, we also reviewed miRNAs that are regulated via traditional senescence-associated secretory phenotype (SASP) cytokines in MSC. Lastly, we summarize miRNAs that have been found to target components of the cell cycle arrest pathways inherently activated in senescence. This review attempts to highlight potential miRNA targets for regenerative medicine applications in age-related musculoskeletal disease.
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Affiliation(s)
- Matthew L Potter
- Department of Orthopedics, Augusta University, Augusta, GA, United States of America
| | - William D Hill
- Medical University of South Carolina, Charleston, SC 29403, United States of America; Ralph H Johnson Veterans Affairs Medical Center, Charleston, SC, 29403, United States of America
| | - Carlos M Isales
- Department of Orthopedics, Augusta University, Augusta, GA, United States of America; Department of Medicine, Augusta University, Augusta, GA, United States of America; Institute of Healthy Aging, Augusta University, Augusta, GA, United States of America
| | - Mark W Hamrick
- Department of Orthopedics, Augusta University, Augusta, GA, United States of America; Institute of Healthy Aging, Augusta University, Augusta, GA, United States of America; Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, United States of America
| | - Sadanand Fulzele
- Department of Orthopedics, Augusta University, Augusta, GA, United States of America; Department of Medicine, Augusta University, Augusta, GA, United States of America; Institute of Healthy Aging, Augusta University, Augusta, GA, United States of America; Department of Cell Biology and Anatomy, Augusta University, Augusta, GA, United States of America.
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12
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Khan K, Baleanu-Gogonea C, Willard B, Gogonea V, Fox PL. 3-Dimensional architecture of the human multi-tRNA synthetase complex. Nucleic Acids Res 2020; 48:8740-8754. [PMID: 32644155 PMCID: PMC7470956 DOI: 10.1093/nar/gkaa569] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/08/2020] [Accepted: 07/06/2020] [Indexed: 11/24/2022] Open
Abstract
In mammalian cells, eight cytoplasmic aminoacyl-tRNA synthetases (AARS), and three non-synthetase proteins, reside in a large multi-tRNA synthetase complex (MSC). AARSs have critical roles in interpretation of the genetic code during protein synthesis, and in non-canonical functions unrelated to translation. Nonetheless, the structure and function of the MSC remain unclear. Partial or complete crystal structures of all MSC constituents have been reported; however, the structure of the holo-MSC has not been resolved. We have taken advantage of cross-linking mass spectrometry (XL-MS) and molecular docking to interrogate the three-dimensional architecture of the MSC in human HEK293T cells. The XL-MS approach uniquely provides structural information on flexibly appended domains, characteristic of nearly all MSC constituents. Using the MS-cleavable cross-linker, disuccinimidyl sulfoxide, inter-protein cross-links spanning all MSC constituents were observed, including cross-links between eight protein pairs not previously known to interact. Intra-protein cross-links defined new structural relationships between domains in several constituents. Unexpectedly, an asymmetric AARS distribution was observed featuring a clustering of tRNA anti-codon binding domains on one MSC face. Possibly, the non-uniform localization improves efficiency of delivery of charged tRNA’s to an interacting ribosome during translation. In summary, we show a highly compact, 3D structural model of the human holo-MSC.
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Affiliation(s)
- Krishnendu Khan
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | | | - Belinda Willard
- Lerner Research Institute Proteomics and Metabolomics Core, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Valentin Gogonea
- Department of Chemistry, Cleveland State University, Cleveland, OH 44115, USA
| | - Paul L Fox
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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13
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Roles of aminoacyl-tRNA synthetase-interacting multi-functional proteins in physiology and cancer. Cell Death Dis 2020; 11:579. [PMID: 32709848 PMCID: PMC7382500 DOI: 10.1038/s41419-020-02794-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 07/03/2020] [Accepted: 07/06/2020] [Indexed: 12/15/2022]
Abstract
Aminoacyl-tRNA synthetases (ARSs) are an important class of enzymes with an evolutionarily conserved mechanism for protein synthesis. In higher eukaryotic systems, eight ARSs and three ARS-interacting multi-functional proteins (AIMPs) form a multi-tRNA synthetase complex (MSC), which seems to contribute to cellular homeostasis. Of these, AIMPs are generally considered as non-enzyme factors, playing a scaffolding role during MSC assembly. Although the functions of AIMPs are not fully understood, increasing evidence indicates that these scaffold proteins usually exert tumor-suppressive activities. In addition, endothelial monocyte-activating polypeptide II (EMAP II), as a cleavage product of AIMP1, and AIMP2-DX2, as a splice variant of AIMP2 lacking exon 2, also have a pivotal role in regulating tumorigenesis. In this review, we summarize the biological functions of AIMP1, EMAP II, AIMP2, AIMP2-DX2, and AIMP3. Also, we systematically introduce their emerging roles in cancer, aiming to provide new ideas for the treatment of cancer.
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14
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Kim C, Park JM, Song Y, Kim S, Moon J. HIF1α-mediated AIMP3 suppression delays stem cell aging via the induction of autophagy. Aging Cell 2019; 18:e12909. [PMID: 30706629 PMCID: PMC6413650 DOI: 10.1111/acel.12909] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 12/31/2022] Open
Abstract
Senescence in stem cells, which occurs as a consequence of chronic responses to the environment, defines the capacity of stem cells for proliferation and differentiation as well as their potential for tissue regeneration and homeostasis maintenance. Although stem cells reside under low oxygen pressure and the availability of oxygen is known to be a crucial determinant in their fate, the key modulators in stem cell aging and the underlying mechanism have yet to be unraveled. Human placenta‐derived mesenchymal stem cells (hpMSCs) were cultured under hypoxia (3% O2) or normoxia (21% O2) to investigate the key factors that regulate stem cell senescence under hypoxic conditions. RNA sequencing results suggested that the expression of aminoacyl‐tRNA synthetase‐interacting multifunctional protein 3 (AIMP3, EEF1E1), an aging inducer, in the hpMSCs was dramatically repressed under hypoxia with concurrent suppression of the aging marker p16INK4a. The hpMSCs that overexpressed AIMP3 under hypoxic conditions displayed significantly decreased proliferation and fewer stem cell characteristics, whereas the downregulation of AIMP3 ameliorated the age‐related senescence of MSCs. Consistent with the results of the hpMSCs, MSCs isolated from the adipose tissue of AIMP3‐overexpressing mice exhibited decreased stem cell functions. Interestingly, AIMP3‐induced senescence is negatively regulated by hypoxia‐inducible factor 1α (HIF1α) and positively regulated by Notch3. Furthermore, we showed that AIMP3 enhanced mitochondrial respiration and suppressed autophagic activity, indicating that the AIMP3‐associated modulation of metabolism and autophagy is a key mechanism in the senescence of stem cells and further suggesting a novel target for interventions against aging.
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Affiliation(s)
- Chul Kim
- Department of Biotechnology, College of Life Science; CHA University; Pocheon-si Korea
| | - Ji-Min Park
- Department of Biotechnology, College of Life Science; CHA University; Pocheon-si Korea
| | - Youngsook Song
- Department of Biotechnology, College of Life Science; CHA University; Pocheon-si Korea
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center; Seoul National University; Seoul Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Technology; Seoul National University; Suwon Korea
| | - Jisook Moon
- Department of Biotechnology, College of Life Science; CHA University; Pocheon-si Korea
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15
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Kim M, Kim H, Kim D, Park C, Huh Y, Jung J, Chung HJ, Jeong NY. Fluorescence-Based Analysis of Noncanonical Functions of Aminoacyl-tRNA Synthetase-Interacting Multifunctional Proteins (AIMPs) in Peripheral Nerves. MATERIALS 2019; 12:ma12071064. [PMID: 30939730 PMCID: PMC6480683 DOI: 10.3390/ma12071064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 03/25/2019] [Accepted: 03/28/2019] [Indexed: 12/30/2022]
Abstract
Aminoacyl-tRNA synthetase-interacting multifunctional proteins (AIMPs) are auxiliary factors involved in protein synthesis related to aminoacyl-tRNA synthetases (ARSs). AIMPs, which are well known as nonenzymatic factors, include AIMP1/p43, AIMP2/p38, and AIMP3/p18. The canonical functions of AIMPs include not only protein synthesis via multisynthetase complexes but also maintenance of the structural stability of these complexes. Several recent studies have demonstrated nontypical (noncanonical) functions of AIMPs, such as roles in apoptosis, inflammatory processes, DNA repair, and so on. However, these noncanonical functions of AIMPs have not been studied in peripheral nerves related to motor and sensory functions. Peripheral nerves include two types of structures: peripheral axons and Schwann cells. The myelin sheath formed by Schwann cells produces saltatory conduction, and these rapid electrical signals control motor and sensory functioning in the service of survival in mammals. Schwann cells play roles not only in myelin sheath formation but also as modulators of nerve degeneration and regeneration. Therefore, it is important to identify the main functions of Schwann cells in peripheral nerves. Here, using immunofluorescence technique, we demonstrated that AIMPs are essential morphological indicators of peripheral nerve degeneration, and their actions are limited to peripheral nerves and not the dorsal root ganglion and the ventral horn of the spinal cord.
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Affiliation(s)
- Muwoong Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
| | - Hyosun Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
- Department of Biomedical Science, Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, Graduation School, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
| | - Dokyoung Kim
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
| | - Chan Park
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
| | - Youngbuhm Huh
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
| | - Junyang Jung
- Department of Anatomy and Neurobiology, College of Medicine, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Korea.
| | - Hyung-Joo Chung
- Department of Anesthesiology and Pain Medicine, College of Medicine, Kosin University, 262, Gamcheon-ro, Seo-gu, Busan 49267, Korea.
| | - Na Young Jeong
- Department of Anatomy and Cell Biology, College of Medicine, Dong-A University, 32, Daesingongwon-ro, Seo-gu, Busan 49201, Korea.
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16
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Kotov DI, Mitchell JS, Pengo T, Ruedl C, Way SS, Langlois RA, Fife BT, Jenkins MK. TCR Affinity Biases Th Cell Differentiation by Regulating CD25, Eef1e1, and Gbp2. THE JOURNAL OF IMMUNOLOGY 2019; 202:2535-2545. [PMID: 30858199 DOI: 10.4049/jimmunol.1801609] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/20/2019] [Indexed: 12/13/2022]
Abstract
Naive CD4+ T lymphocytes differentiate into various Th cell subsets following TCR binding to microbial peptide:MHC class II (p:MHCII) complexes on dendritic cells (DCs). The affinity of the TCR interaction with p:MHCII plays a role in Th differentiation by mechanisms that are not completely understood. We found that low-affinity TCRs biased mouse naive T cells to become T follicular helper (Tfh) cells, whereas higher-affinity TCRs promoted the formation of Th1 or Th17 cells. We explored the basis for this phenomenon by focusing on IL-2R signaling, which is known to promote Th1 and suppress Tfh cell differentiation. SIRP⍺+ DCs produce abundant p:MHCII complexes and consume IL-2, whereas XCR1+ DCs weakly produce p:MHCII but do not consume IL-2. We found no evidence, however, of preferential interactions between Th1 cell-prone, high-affinity T cells and XCR1+ DCs or Tfh cell-prone, low-affinity T cells and SIRP⍺+ DCs postinfection with bacteria expressing the peptide of interest. Rather, high-affinity T cells sustained IL-2R expression longer and expressed two novel Th cell differentiation regulators, Eef1e1 and Gbp2, to a higher level than low-affinity T cells. These results suggest that TCR affinity does not influence Th cell differentiation by biasing T cell interactions with IL-2-consuming DCs, but instead, directly regulates genes in naive T cells that control the differentiation process.
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Affiliation(s)
- Dmitri I Kotov
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455.,Center for Immunology, University of Minnesota, Minneapolis, MN 55455
| | - Jason S Mitchell
- Center for Immunology, University of Minnesota, Minneapolis, MN 55455.,University Imaging Centers, University of Minnesota, Minneapolis, MN 55455.,Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Thomas Pengo
- University of Minnesota Informatics Institute, University of Minnesota, Minneapolis, MN 55455
| | - Christiane Ruedl
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
| | - Sing Sing Way
- Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229; and.,Perinatal Institute, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229
| | - Ryan A Langlois
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455.,Center for Immunology, University of Minnesota, Minneapolis, MN 55455
| | - Brian T Fife
- Center for Immunology, University of Minnesota, Minneapolis, MN 55455.,Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Marc K Jenkins
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55455; .,Center for Immunology, University of Minnesota, Minneapolis, MN 55455
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17
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Kim SM, Jeon Y, Kim D, Jang H, Bae JS, Park MK, Kim H, Kim S, Lee H. AIMP3 depletion causes genome instability and loss of stemness in mouse embryonic stem cells. Cell Death Dis 2018; 9:972. [PMID: 30250065 PMCID: PMC6155375 DOI: 10.1038/s41419-018-1037-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/04/2018] [Accepted: 09/05/2018] [Indexed: 12/16/2022]
Abstract
Aminoacyl-tRNA synthetase-interacting multifunctional protein-3 (AIMP3) is a component of the multi-aminoacyl-tRNA synthetase complex and is involved in diverse cellular processes. Given that AIMP3 deficiency causes early embryonic lethality in mice, AIMP3 is expected to play a critical role in early mouse development. To elucidate a functional role of AIMP3 in early mouse development, we induced AIMP3 depletion in mouse embryonic stem cells (mESCs) derived from blastocysts of AIMP3f/f; CreERT2 mice. In the present study, AIMP3 depletion resulted in loss of self-renewal and ability to differentiate to three germ layers in mESCs. AIMP3 depletion led to accumulation of DNA damage by blocking double-strand break repair, in particular homologous recombination. Through microarray analysis, the p53 signaling pathway was identified as being activated in AIMP3-depleted mESCs. Knockdown of p53 rescued loss of stem cell characteristics by AIMP3 depletion in mESCs. These results imply that AIMP3 depletion in mESCs leads to accumulation of DNA damage and p53 transactivation, resulting in loss of stemness. We propose that AIMP3 is involved in maintenance of genome stability and stemness in mESCs.
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Affiliation(s)
- Sun Mi Kim
- Graduate School of Cancer Science and Policy, Research Institute, National Cancer Center, Gyeonggi, 10408, Republic of Korea
| | - Yoon Jeon
- Research Institute, National Cancer Center, Gyeonggi, 10408, Republic of Korea
| | - Doyeun Kim
- Medicinal Bioconvergence Research Center, Department of Pharmacology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Hyonchol Jang
- Research Institute, National Cancer Center, Gyeonggi, 10408, Republic of Korea
| | - June Sung Bae
- Research Institute, National Cancer Center, Gyeonggi, 10408, Republic of Korea
| | - Mi Kyung Park
- Research Institute, National Cancer Center, Gyeonggi, 10408, Republic of Korea
| | - Hongtae Kim
- Department of Biological Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center, Department of Pharmacology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Ho Lee
- Research Institute, National Cancer Center, Gyeonggi, 10408, Republic of Korea.
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18
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Krishnamoorthy V, Khanna R, Parnaik VK. E3 ubiquitin ligase HECW2 targets PCNA and lamin B1. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:1088-1104. [PMID: 29753763 DOI: 10.1016/j.bbamcr.2018.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/20/2018] [Accepted: 05/07/2018] [Indexed: 12/21/2022]
Abstract
Lamins constitute the major architectural proteins of the nuclear lamina that help in maintaining nuclear organization. Mutations in lamins are associated with diverse degenerative diseases, collectively termed laminopathies. HECW2, a HECT-type E3 ubiquitin ligase, is transcriptionally upregulated in HeLa cells expressing Emery-Dreifuss muscular dystrophy-causing-lamin A mutants. However, the role of HECW2 upregulation in mediating downstream effects in lamin mutant-expressing cells was previously unexplored. Here, we show that HECW2 interacts with two lamin A-binding proteins, proliferating cell nuclear antigen (PCNA), via a canonical PCNA-interacting protein (PIP) motif, and lamin B1. HECW2 mediates their ubiquitination and targets them for proteasomal degradation. Cells expressing lamin A mutants G232E and Q294P, in which HECW2 is upregulated, show increased proteasomal degradation of PCNA and lamin B1 most likely mediated by HECW2. Our findings establish HECW2 as an E3 ubiquitin ligase for PCNA and lamin B1 which regulates their levels in laminopathic cells. We also found that HECW2 interacts with wild-type lamin A and ubiquitinates it and this interaction is reduced in case of lamin mutants G232E and Q294P. Our findings suggest that interplay among HECW2, lamin A, PCNA, and lamin B1 determines their respective homeostatic levels in the cell and dysregulation of these interactions may contribute to the pathogenicity of laminopathies.
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Affiliation(s)
| | - Richa Khanna
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Veena K Parnaik
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.
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19
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Simon DN, Wriston A, Fan Q, Shabanowitz J, Florwick A, Dharmaraj T, Peterson SB, Gruenbaum Y, Carlson CR, Grønning-Wang LM, Hunt DF, Wilson KL. OGT ( O-GlcNAc Transferase) Selectively Modifies Multiple Residues Unique to Lamin A. Cells 2018; 7:E44. [PMID: 29772801 PMCID: PMC5981268 DOI: 10.3390/cells7050044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 12/31/2022] Open
Abstract
The LMNA gene encodes lamins A and C with key roles in nuclear structure, signaling, gene regulation, and genome integrity. Mutations in LMNA cause over 12 diseases ('laminopathies'). Lamins A and C are identical for their first 566 residues. However, they form separate filaments in vivo, with apparently distinct roles. We report that lamin A is β-O-linked N-acetylglucosamine-(O-GlcNAc)-modified in human hepatoma (Huh7) cells and in mouse liver. In vitro assays with purified O-GlcNAc transferase (OGT) enzyme showed robust O-GlcNAcylation of recombinant mature lamin A tails (residues 385⁻646), with no detectable modification of lamin B1, lamin C, or 'progerin' (Δ50) tails. Using mass spectrometry, we identified 11 O-GlcNAc sites in a 'sweet spot' unique to lamin A, with up to seven sugars per peptide. Most sites were unpredicted by current algorithms. Double-mutant (S612A/T643A) lamin A tails were still robustly O-GlcNAc-modified at seven sites. By contrast, O-GlcNAcylation was undetectable on tails bearing deletion Δ50, which causes Hutchinson⁻Gilford progeria syndrome, and greatly reduced by deletion Δ35. We conclude that residues deleted in progeria are required for substrate recognition and/or modification by OGT in vitro. Interestingly, deletion Δ35, which does not remove the majority of identified O-GlcNAc sites, does remove potential OGT-association motifs (lamin A residues 622⁻625 and 639⁻645) homologous to that in mouse Tet1. These biochemical results are significant because they identify a novel molecular pathway that may profoundly influence lamin A function. The hypothesis that lamin A is selectively regulated by OGT warrants future testing in vivo, along with two predictions: genetic variants may contribute to disease by perturbing OGT-dependent regulation, and nutrient or other stresses might cause OGT to misregulate wildtype lamin A.
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Affiliation(s)
- Dan N Simon
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Amanda Wriston
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| | - Qiong Fan
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
| | - Jeffrey Shabanowitz
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
| | - Alyssa Florwick
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Tejas Dharmaraj
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
| | - Sherket B Peterson
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram Jerusalem 91904, Israel.
| | - Cathrine R Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0450 Oslo, Norway.
| | - Line M Grønning-Wang
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway.
| | - Donald F Hunt
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
- Department of Pathology, University of Virginia, Charlottesville, VA 22904, USA.
| | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA.
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20
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Borroni AP, Emanuelli A, Shah PA, Ilić N, Apel-Sarid L, Paolini B, Manikoth Ayyathan D, Koganti P, Levy-Cohen G, Blank M. Smurf2 regulates stability and the autophagic-lysosomal turnover of lamin A and its disease-associated form progerin. Aging Cell 2018; 17. [PMID: 29405587 PMCID: PMC5847874 DOI: 10.1111/acel.12732] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2018] [Indexed: 12/19/2022] Open
Abstract
A‐lamins, encoded by the LMNA gene, are major structural components of the nuclear lamina coordinating essential cellular processes. Mutations in the LMNA gene and/or alterations in its expression levels have been linked to a distinct subset of human disorders, collectively known as laminopathies, and to cancer. Mechanisms regulating A‐lamins are mostly obscure. Here, we identified E3 ubiquitin ligase Smurf2 as a physiological regulator of lamin A and its disease‐associated mutant form progerin (LAΔ50), whose expression underlies the development of Hutchinson‐Gilford progeria syndrome (HGPS), a devastating premature aging syndrome. We show that Smurf2 directly binds, ubiquitinates, and negatively regulates the expression of lamin A and progerin in Smurf2 dose‐ and E3 ligase‐dependent manners. Overexpression of catalytically active Smurf2 promotes the autophagic–lysosomal breakdown of lamin A and progerin, whereas Smurf2 depletion increases lamin A levels. Remarkably, acute overexpression of Smurf2 in progeria fibroblasts was able to significantly reduce the nuclear deformability. Furthermore, we demonstrate that the reciprocal relationship between Smurf2 and A‐lamins is preserved in different types of mouse and human normal and cancer tissues. These findings establish Smurf2 as an essential regulator of lamin A and progerin and lay a foundation for evaluating the efficiency of progerin clearance by Smurf2 in HGPS, and targeting of the Smurf2–lamin A axis in age‐related diseases such as cancer.
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Affiliation(s)
- Aurora Paola Borroni
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Andrea Emanuelli
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Pooja Anil Shah
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Nataša Ilić
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Liat Apel-Sarid
- Department of Pathology; The Galilee Medical Center; Nahariya Israel
| | - Biagio Paolini
- Department of Pathology and Laboratory Medicine; IRCCS Fondazione; Istituto Nazionale dei Tumori; Milan Italy
| | - Dhanoop Manikoth Ayyathan
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Praveen Koganti
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Gal Levy-Cohen
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
| | - Michael Blank
- Laboratory of Molecular and Cellular Cancer Biology; Azrieli Faculty of Medicine; Bar-Ilan University; Safed Israel
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21
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Tao Y, Fang P, Kim S, Guo M, Young NL, Marshall AG. Mapping the contact surfaces in the Lamin A:AIMP3 complex by hydrogen/deuterium exchange FT-ICR mass spectrometry. PLoS One 2017; 12:e0181869. [PMID: 28797100 PMCID: PMC5552228 DOI: 10.1371/journal.pone.0181869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/07/2017] [Indexed: 11/23/2022] Open
Abstract
Aminoacyl-tRNA synthetases-interacting multifunctional protein3 (AIMP3/p18) is involved in the macromolecular tRNA synthetase complex via its interaction with several aminoacyl-tRNA synthetases. Recent reports reveal a novel function of AIMP3 as a tumor suppressor by accelerating cellular senescence and causing defects in nuclear morphology. AIMP3 specifically mediates degradation of mature Lamin A (LmnA), a major component of the nuclear envelope matrix; however, the mechanism of how AIMP3 interacts with LmnA is unclear. Here we report solution-phase hydrogen/deuterium exchange (HDX) for AIMP3, LmnA, and AIMP3 in association with the LmnA C-terminus. Reversed-phase LC coupled with LTQ 14.5 T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) results in high mass accuracy and resolving power for comparing the D-uptake profiles for AIMP3, LmnA, and their complex. The results show that the AIMP3-LmnA interaction involves one of the two putative binding sites and an adjacent novel interface on AIMP3. LmnA binds AIMP3 via its extreme C-terminus. Together these findings provide a structural insight for understanding the interaction between AIMP3 and LmnA in AIMP3 degradation.
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Affiliation(s)
- Yeqing Tao
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, United States of America
| | - Pengfei Fang
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Sunghoon Kim
- Medicinal Bioconvergence Research Center, College of Pharmacy, Seoul National University, Seoul, South Korea
| | - Min Guo
- Department of Cancer Biology, The Scripps Research Institute, Scripps Florida, Jupiter, Florida, United States of America
| | - Nicolas L. Young
- Verna & Marrs McLean Department of Biochemistry & Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Alan G. Marshall
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, United States of America
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, United States of America
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Abstract
Progeroid mouse models display phenotypes in multiple organ systems that suggest premature aging and resemble features of natural aging of both mice and humans. The prospect of a significant increase in the global elderly population within the next decades has led to the emergence of "geroscience," which aims at elucidating the molecular mechanisms involved in aging. Progeroid mouse models are frequently used in geroscience as they provide insight into the molecular mechanisms that are involved in the highly complex process of natural aging. This review provides an overview of the most commonly reported nonneoplastic macroscopic and microscopic pathologic findings in progeroid mouse models (eg, osteoporosis, osteoarthritis, degenerative joint disease, intervertebral disc degeneration, kyphosis, sarcopenia, cutaneous atrophy, wound healing, hair loss, alopecia, lymphoid atrophy, cataract, corneal endothelial dystrophy, retinal degenerative diseases, and vascular remodeling). Furthermore, several shortcomings in pathologic analysis and descriptions of these models are discussed. Progeroid mouse models are valuable models for aging, but thorough knowledge of both the mouse strain background and the progeria-related phenotype is required to guide interpretation and translation of the pathology data.
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Affiliation(s)
- L Harkema
- Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - S A Youssef
- Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - A de Bruin
- Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands Department of Pediatrics, Division of Molecular Genetics, University Medical Center Groningen, Groningen, The Netherlands
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Aljada A, Doria J, Saleh AM, Al-Matar SH, AlGabbani S, Shamsa HB, Al-Bawab A, Ahmed AA. Altered Lamin A/C splice variant expression as a possible diagnostic marker in breast cancer. Cell Oncol (Dordr) 2016; 39:161-74. [PMID: 26732077 DOI: 10.1007/s13402-015-0265-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2015] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Lamin A/C alternative splice variants (Lamin A, Lamin C, Lamin AΔ10 and Lamin AΔ50) have been implicated in cell cycle regulation, DNA replication, transcription regulation, cellular differentiation, apoptosis and aging. In addition, loss of Lamin A/C expression has been observed in several cancers, including breast cancer, and it has been found that Lamin A/C suppression may lead to cancer-like aberrations in nuclear morphology and aneuploidy. Based on these observations, we hypothesized that Lamin A/C transcript variant quantification might be employed for the diagnosis of breast cancer. METHODS Newly designed TaqMan qRT-PCR assays for the analysis of Lamin A/C splice variants were validated and their use as biomarkers for the diagnosis of breast cancer was assessed using 16 normal breast tissues and 128 breast adenocarcinomas. In addition, the expression levels of the Lamin A/C transcript variants were measured in samples derived from seven other types of cancer. RESULTS We found that the expression level of Lamin C was significantly increased in the breast tumors tested, whereas the expression levels of Lamin A and Lamin AΔ50 were significantly decreased. No significant change in Lamin AΔ10 expression was observed. Our data also indicated that the Lamin C : Lamin A mRNA ratio was increased in all clinical stages of breast cancer. Additionally, we observed increased Lamin C : Lamin A mRNA ratios in liver, lung and thyroid carcinomas and in colon, ovary and prostate adenocarcinomas. CONCLUSIONS From our data we conclude that the Lamin C : Lamin A mRNA ratio is increased in breast cancer and that this mRNA ratio may be of diagnostic use in all clinical stages of breast cancer and, possibly, also in liver, lung, thyroid, colon, ovary and prostate cancers.
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Affiliation(s)
- Ahmad Aljada
- Department of Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia.
- King Abdullah International Medical Research Center (KAIMRC), National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia.
| | - Joseph Doria
- Department of Neurology, Virginia Commonwealth University Medical Center, Richmond, VA, USA
| | - Ayman M Saleh
- Department of Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
- King Abdullah International Medical Research Center (KAIMRC), National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Shahad H Al-Matar
- Department of Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
| | - Sarah AlGabbani
- Department of Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
| | - Heba Bani Shamsa
- King Abdullah International Medical Research Center (KAIMRC), National Guard Health Affairs, Riyadh, Kingdom of Saudi Arabia
| | - Ahmad Al-Bawab
- Department of Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
| | - Altayeb Abdalla Ahmed
- Department of Basic Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
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Gabriel D, Roedl D, Gordon LB, Djabali K. Sulforaphane enhances progerin clearance in Hutchinson-Gilford progeria fibroblasts. Aging Cell 2015; 14:78-91. [PMID: 25510262 PMCID: PMC4326906 DOI: 10.1111/acel.12300] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2014] [Indexed: 01/05/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS, OMIM 176670) is a rare multisystem childhood premature aging disorder linked to mutations in the LMNA gene. The most common HGPS mutation is found at position G608G within exon 11 of the LMNA gene. This mutation results in the deletion of 50 amino acids at the carboxyl-terminal tail of prelamin A, and the truncated protein is called progerin. Progerin only undergoes a subset of the normal post-translational modifications and remains permanently farnesylated. Several attempts to rescue the normal cellular phenotype with farnesyltransferase inhibitors (FTIs) and other compounds have resulted in partial cellular recovery. Using proteomics, we report here that progerin induces changes in the composition of the HGPS nuclear proteome, including alterations to several components of the protein degradation pathways. Consequently, proteasome activity and autophagy are impaired in HGPS cells. To restore protein clearance in HGPS cells, we treated HGPS cultures with sulforaphane (SFN), an antioxidant derived from cruciferous vegetables. We determined that SFN stimulates proteasome activity and autophagy in normal and HGPS fibroblast cultures. Specifically, SFN enhances progerin clearance by autophagy and reverses the phenotypic changes that are the hallmarks of HGPS. Therefore, SFN is a promising therapeutic avenue for children with HGPS.
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Affiliation(s)
- Diana Gabriel
- Department of Medicine, Epigenetics of skin Aging and Institute for Medical Engineering, Technische Universität München (TUM)Garching bei München, Germany
| | - Daniela Roedl
- Department of Medicine, Epigenetics of skin Aging and Institute for Medical Engineering, Technische Universität München (TUM)Garching bei München, Germany
| | - Leslie B Gordon
- Department of Pediatrics, Alpert Medical School of Brown University and Hasbro Children's HospitalProvidence, RI, USA
- Boston Children's Hospital and Harvard UniversityBoston, MA, USA
| | - Karima Djabali
- Department of Medicine, Epigenetics of skin Aging and Institute for Medical Engineering, Technische Universität München (TUM)Garching bei München, Germany
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25
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Lee S, Yu KR, Ryu YS, Oh YS, Hong IS, Kim HS, Lee JY, Kim S, Seo KW, Kang KS. miR-543 and miR-590-3p regulate human mesenchymal stem cell aging via direct targeting of AIMP3/p18. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9724. [PMID: 25465621 PMCID: PMC4259092 DOI: 10.1007/s11357-014-9724-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/22/2014] [Indexed: 06/04/2023]
Abstract
Previously, AIMP3 (aminoacyl-tRNAsynthetase-interacting multifunctional protein-3) was shown to be involved in the macromolecular tRNA synthetase complex or to act as a tumor suppressor. In this study, we report a novel role of AIMP3/p18 in the cellular aging of human mesenchymal stem cells (hMSCs). We found that AIMP3/p18 expression significantly increased in senescent hMSCs and in aged mouse bone marrow-derived MSCs (mBM-MSCs). AIMP3/p18 overexpression is sufficient to induce the cellular senescence phenotypes with compromised clonogenicity and adipogenic differentiation potential. To identify the upstream regulators of AIMP3/p18 during senescence, we screened for potential epigenetic regulators and for miRNAs. We found that the levels of miR-543 and miR-590-3p significantly decreased under senescence-inducing conditions, whereas the AIMP3/p18 protein levels increased. We demonstrate for the first time that miR-543 and miR-590-3p are able to decrease AIMP3/p18 expression levels through direct binding to the AIMP/p18 transcripts, which further compromised the induction of the senescence phenotype. Taken together, our data demonstrate that AIMP3/p18 regulates cellular aging in hMSCs possibly through miR-543 and miR-590-3p.
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Affiliation(s)
- Seunghee Lee
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Institute for Stem Cell and Regenerative Medicine in Kang Stem Biotech, Biotechnology Incubating Center, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Kyung-Rok Yu
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Young-Sil Ryu
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Young Sun Oh
- />Medicinal Bioconvergence Research Center, Seoul National University, Seoul, 151-742 Republic of Korea
- />WCU Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, 443-270 Republic of Korea
| | - In-Sun Hong
- />Department of Molecular Medicine, Gachon University, Incheon, Republic of Korea
- />Lee Gil Ya Cancer and Diabetes Institute, Incheon, Republic of Korea
| | - Hyung-Sik Kim
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Institute for Stem Cell and Regenerative Medicine in Kang Stem Biotech, Biotechnology Incubating Center, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Jin Young Lee
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Sunghoon Kim
- />Medicinal Bioconvergence Research Center, Seoul National University, Seoul, 151-742 Republic of Korea
- />WCU Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Suwon, 443-270 Republic of Korea
| | - Kwang-Won Seo
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Institute for Stem Cell and Regenerative Medicine in Kang Stem Biotech, Biotechnology Incubating Center, Seoul National University, Seoul, 151-742 Republic of Korea
| | - Kyung-Sun Kang
- />Adult Stem Cell Research Center, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
- />Research Institute for Veterinary Medicine, College of Veterinary Medicine, Seoul National University, Seoul, 151-742 Republic of Korea
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26
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Do lamin A and lamin C have unique roles? Chromosoma 2014; 124:1-12. [PMID: 25283634 DOI: 10.1007/s00412-014-0484-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 08/12/2014] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
Abstract
The A-type lamins, lamin A and lamin C, generated from a single gene, LMNA, are major structural components of the nuclear lamina. The two alternative splice products have mostly been studied together because they have been considered to be interchangeable. However, several lines of evidence indicate that in spite of being generated from the same gene and having high similarities in their primary sequences, the two isoforms are not equivalent in different biological aspects in both health and disease. The key question is whether they have both overlapping and unique functions and whether they are distinctly regulated. Based on the so far available experimental evidence, lamin A appears to be the most regulated A-type isoform during development, aging, and disease which indicates that lamin A is implicated in many different biological aspects and may have a greater repertoire of specialized functions than lamin C. The aim of this review is to point out differences between the two major LMNA splice variants and the consequences of these differences on their functions. This may guide further research and be of prime importance for the understanding of the pathogenesis of LMNA mutations.
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27
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Gurung PMS, Veerakumarasivam A, Williamson M, Counsell N, Douglas J, Tan WS, Feber A, Crabb SJ, Short SC, Freeman A, Powles T, Hoskin PJ, West CM, Kelly JD. Loss of expression of the tumour suppressor gene AIMP3 predicts survival following radiotherapy in muscle-invasive bladder cancer. Int J Cancer 2014; 136:709-20. [PMID: 24917520 DOI: 10.1002/ijc.29022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 05/05/2014] [Accepted: 05/08/2014] [Indexed: 11/10/2022]
Abstract
The aim of this study was to test the utility of AIMP3, an upstream regulator of DNA damage response following genotoxic stress, as a clinical biomarker in muscle-invasive bladder cancer (MIBC). AIMP3 was identified from a meta-analysis of a global gene-expression dataset. AIMP3 protein expression was determined by immunohistochemistry on a customised bladder cancer tissue-microarray (TMA). The mechanism of gene silencing was probed using methylation-specific PCR. The association between AIMP3 expression, Tp53 transactivity and genomic stability was analysed. In vitro AIMP3 translocation to the nucleus in response to ionising radiation was demonstrated using immunofluorescence. Radiosensitisation effects of siRNA-mediated AIMP3-knockdown were measured using colony forming assays. TMAs derived from patients enrolled in BCON, a Phase III multicentre radiotherapy trial in bladder cancer (ISRCTN45938399) were used to evaluate the association between AIMP3 expression and survival. The prognostic value of AIMP3 expression was determined in a TMA derived from patients treated by radical cystectomy. Loss of AIMP3 expression was frequent in MIBC and associated with impaired Tp53 transactivity and genomic instability. AIMP3-knockdown was associated with an increase in radioresistance. Loss of AIMP3 expression was associated with survival in MIBC patients following radiotherapy (HR = 0.53; 95% CI: 0.36 to 0.78, p = 0.002) but was not prognostic in the cystectomy set. In conclusion, AIMP3 expression is lost in a subset of bladder cancers and is significantly predictive of survival following radiotherapy in MIBC patients.
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Affiliation(s)
- Pratik M S Gurung
- Division of Surgery and Interventional Science, University College London (UCL), London, United Kingdom
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28
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Snider NT, Omary MB. Post-translational modifications of intermediate filament proteins: mechanisms and functions. Nat Rev Mol Cell Biol 2014; 15:163-77. [PMID: 24556839 PMCID: PMC4079540 DOI: 10.1038/nrm3753] [Citation(s) in RCA: 370] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intermediate filaments (IFs) are cytoskeletal and nucleoskeletal structures that provide mechanical and stress-coping resilience to cells, contribute to subcellular and tissue-specific biological functions, and facilitate intracellular communication. IFs, including nuclear lamins and those in the cytoplasm (keratins, vimentin, desmin, neurofilaments and glial fibrillary acidic protein, among others), are functionally regulated by post-translational modifications (PTMs). Proteomic advances highlight the enormous complexity and regulatory potential of IF protein PTMs, which include phosphorylation, glycosylation, sumoylation, acetylation and prenylation, with novel modifications becoming increasingly appreciated. Future studies will need to characterize their on-off mechanisms, crosstalk and utility as biomarkers and targets for diseases involving the IF cytoskeleton.
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Affiliation(s)
- Natasha T. Snider
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
- VA Ann Arbor Healthcare System, Ann Arbor, Michigan
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29
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Boyette LB, Tuan RS. Adult Stem Cells and Diseases of Aging. J Clin Med 2014; 3:88-134. [PMID: 24757526 PMCID: PMC3992297 DOI: 10.3390/jcm3010088] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 12/15/2013] [Accepted: 12/17/2013] [Indexed: 02/06/2023] Open
Abstract
Preservation of adult stem cells pools is critical for maintaining tissue homeostasis into old age. Exhaustion of adult stem cell pools as a result of deranged metabolic signaling, premature senescence as a response to oncogenic insults to the somatic genome, and other causes contribute to tissue degeneration with age. Both progeria, an extreme example of early-onset aging, and heritable longevity have provided avenues to study regulation of the aging program and its impact on adult stem cell compartments. In this review, we discuss recent findings concerning the effects of aging on stem cells, contributions of stem cells to age-related pathologies, examples of signaling pathways at work in these processes, and lessons about cellular aging gleaned from the development and refinement of cellular reprogramming technologies. We highlight emerging therapeutic approaches to manipulation of key signaling pathways corrupting or exhausting adult stem cells, as well as other approaches targeted at maintaining robust stem cell pools to extend not only lifespan but healthspan.
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Affiliation(s)
- Lisa B Boyette
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA; ; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA
| | - Rocky S Tuan
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15219, USA; ; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA ; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
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30
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Abstract
When compared to other conserved housekeeping protein families, such as ribosomal proteins, during the evolution of higher eukaryotes, aminoacyl-tRNA synthetases (aaRSs) show an apparent high propensity to add new sequences, and especially new domains. The stepwise emergence of those new domains is consistent with their involvement in a broad range of biological functions beyond protein synthesis, and correlates with the increasing biological complexity of higher organisms. These new domains have been extensively characterized based on their evolutionary origins and their sequence, structural, and functional features. While some of the domains are uniquely found in aaRSs and may have originated from nucleic acid binding motifs, others are common domain modules mediating protein-protein interactions that play a critical role in the assembly of the multi-synthetase complex (MSC). Interestingly, the MSC has emerged from a miniature complex in yeast to a large stable complex in humans. The human MSC consists of nine aaRSs (LysRS, ArgRS, GlnRS, AspRS, MetRS, IleRS, LeuRS, GluProRS, and bifunctional aaRs) and three scaffold proteins (AIMP1/p43, AIMP2/p38, and AIMP3/p18), and has a molecular weight of 1.5 million Dalton. The MSC has been proposed to have a functional dualism: facilitating protein synthesis and serving as a reservoir of non-canonical functions associated with its synthetase and non-synthetase components. Importantly, domain additions and functional expansions are not limited to the components of the MSC and are found in almost all aaRS proteins. From a structural perspective, multi-functionalities are represented by multiple conformational states. In fact, alternative conformations of aaRSs have been generated by various mechanisms from proteolysis to alternative splicing and posttranslational modifications, as well as by disease-causing mutations. Therefore, the metamorphosis between different conformational states is connected to the activation and regulation of the novel functions of aaRSs in higher eukaryotes.
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Affiliation(s)
- Min Guo
- Department of Cancer Biology, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33410, USA,
| | - Xiang-Lei Yang
- Department of Cancer Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA,
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Al-Saaidi R, Rasmussen TB, Palmfeldt J, Nissen PH, Beqqali A, Hansen J, Pinto YM, Boesen T, Mogensen J, Bross P. The LMNA mutation p.Arg321Ter associated with dilated cardiomyopathy leads to reduced expression and a skewed ratio of lamin A and lamin C proteins. Exp Cell Res 2013; 319:3010-9. [PMID: 24001739 DOI: 10.1016/j.yexcr.2013.08.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 07/31/2013] [Accepted: 08/19/2013] [Indexed: 11/19/2022]
Abstract
Dilated cardiomyopathy (DCM) is a disease of the heart muscle characterized by cardiac chamber enlargement and reduced systolic function of the left ventricle. Mutations in the LMNA gene represent the most frequent known genetic cause of DCM associated with disease of the conduction systems. The LMNA gene generates two major transcripts encoding the nuclear lamina major components lamin A and lamin C by alternative splicing. Both haploinsuffiency and dominant negative effects have been proposed as disease mechanism for premature termination codon (PTC) mutations in LMNA. These mechanisms however are still not clearly established. In this study, we used a representative LMNA nonsense mutation, p.Arg321Ter, to shed light on the molecular disease mechanisms. Cultured fibroblasts from three DCM patients carrying this mutation were analyzed. Quantitative reverse transcriptase PCR and sequencing of these PCR products indicated that transcripts from the mutant allele were degraded by the nonsense-mediated mRNA decay (NMD) mechanism. The fact that no truncated mutant protein was detectable in western blot (WB) analysis strengthens the notion that the mutant transcript is efficiently degraded. Furthermore, WB analysis showed that the expression of lamin C protein was reduced by the expected approximately 50%. Clearly decreased lamin A and lamin C levels were also observed by immunofluorescence microscopy analysis. However, results from both WB and nano-liquid chromatography/mass spectrometry demonstrated that the levels of lamin A protein were more reduced suggesting an effect on expression of lamin A from the wild type allele. PCR analysis of the ratio of lamin A to lamin C transcripts showed unchanged relative amounts of lamin A transcript suggesting that the effect on the wild type allele was operative at the protein level. Immunofluorescence microscopy analysis showed no abnormal nuclear morphology of patient fibroblast cells. Based on these data, we propose that heterozygosity for the nonsense mutation causes NMD degradation of the mutant transcripts blocking expression of the truncated mutant protein and an additional trans effect on lamin A protein levels expressed from the wild type allele. We discuss the possibility that skewing of the lamin A to lamin C ratio may contribute to ensuing processes that destabilize cardiomyocytes and trigger cardiomyopathy.
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Affiliation(s)
- Rasha Al-Saaidi
- Research Unit for Molecular Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark
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Moskalev AA, Shaposhnikov MV, Plyusnina EN, Zhavoronkov A, Budovsky A, Yanai H, Fraifeld VE. The role of DNA damage and repair in aging through the prism of Koch-like criteria. Ageing Res Rev 2013; 12:661-84. [PMID: 22353384 DOI: 10.1016/j.arr.2012.02.001] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 01/27/2012] [Accepted: 02/06/2012] [Indexed: 12/21/2022]
Abstract
Since the first publication on Somatic Mutation Theory of Aging (Szilárd, 1959), a great volume of knowledge in the field has been accumulated. Here we attempted to organize the evidence "for" and "against" the hypothesized causal role of DNA damage and mutation accumulation in aging in light of four Koch-like criteria. They are based on the assumption that some quantitative relationship between the levels of DNA damage/mutations and aging rate should exist, so that (i) the longer-lived individuals or species would have a lower rate of damage than the shorter-lived, and (ii) the interventions that modulate the level of DNA damage and repair capacity should also modulate the rate of aging and longevity and vice versa. The analysis of how the existing data meets the proposed criteria showed that many gaps should still be filled in order to reach a clear-cut conclusion. As a perspective, it seems that the main emphasis in future studies should be put on the role of DNA damage in stem cell aging.
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Citric acid cycle and the origin of MARS. Trends Biochem Sci 2013; 38:222-8. [PMID: 23415030 DOI: 10.1016/j.tibs.2013.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 01/01/2013] [Accepted: 01/09/2013] [Indexed: 10/27/2022]
Abstract
The vertebrate multiaminoacyl tRNA synthetase complex (MARS) is an assemblage of nine aminoacyl tRNA synthetases (ARSs) and three non-synthetase scaffold proteins, aminoacyl tRNA synthetase complex-interacting multifunctional protein (AIMP)1, AIMP2, and AIMP3. The evolutionary origin of the MARS is unclear, as is the significance of the inclusion of only nine of 20 tRNA synthetases. Eight of the nine amino acids corresponding to ARSs of the MARS are derived from two citric acid cycle intermediates, α-ketoglutatrate and oxaloacetate. We propose that the metabolic link with the citric acid cycle, the appearance of scaffolding proteins AIMP2 and AIMP3, and the subsequent disappearance of the glyoxylate cycle, together facilitated the origin of the MARS in a common ancestor of metazoans and choanoflagellates.
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Protein-protein interactions and multi-component complexes of aminoacyl-tRNA synthetases. Top Curr Chem (Cham) 2013; 344:119-44. [PMID: 24072587 DOI: 10.1007/128_2013_479] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Protein-protein interaction occurs transiently or stably when two or more proteins bind together to mediate a wide range of cellular processes such as protein modification, signal transduction, protein trafficking, and structural folding. The macromolecules involved in protein biosynthesis such as aminoacyl-tRNA synthetase (ARS) have a number of protein-protein interactions. The mammalian multi-tRNA synthetase complex (MSC) consists of eight different enzymes: EPRS, IRS, LRS, QRS, MRS, KRS, RRS, and DRS, and three auxiliary proteins: AIMP1/p43, AIMP2/p38, and AIMP/p18. The distinct ARS proteins are also connected to diverse protein networks to carry out biological functions. In this chapter we first show the protein networks of the entire MSC and explain how MSC components interact with or can regulate other proteins. Finally, it is pointed out that the understanding of protein-protein interaction mechanism will provide insight to potential therapeutic application for diseases related to the MSC network.
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Abstract
Although aminoacyl-tRNA synthetases (ARSs) and ARS-interacting multi-functional proteins (AIMPs) have long been recognized as housekeeping proteins, evidence indicating that they play a key role in regulating cancer is now accumulating. In this chapter we will review the conventional and non-conventional functions of ARSs and AIMPs with respect to carcinogenesis. First, we will address how ARSs and AIMPs are altered in terms of expression, mutation, splicing, and post-translational modifications. Second, the molecular mechanisms for ARSs' and AIMPs' involvement in the initiation, maintenance, and progress of carcinogenesis will be covered. Finally, we will introduce the development of therapeutic approaches that target ARSs and AIMPs with the goal of treating cancer.
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Reunert J, Wentzell R, Walter M, Jakubiczka S, Zenker M, Brune T, Rust S, Marquardt T. Neonatal progeria: increased ratio of progerin to lamin A leads to progeria of the newborn. Eur J Hum Genet 2012; 20:933-7. [PMID: 22419169 PMCID: PMC3421121 DOI: 10.1038/ejhg.2012.36] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 12/20/2011] [Accepted: 01/31/2012] [Indexed: 12/15/2022] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is an important model disease for premature ageing. Affected children appear healthy at birth, but develop the first symptoms during their first year of life. They die at an average age of 13 years, mostly because of myocardial infarction or stroke. Classical progeria is caused by the heterozygous point mutation c.1824C>T in the LMNA gene, which activates a cryptic splice site. The affected protein cannot be processed correctly to mature lamin A, but is modified into a farnesylated protein truncated by 50 amino acids (progerin). Three more variations in LMNA result in the same mutant protein, but different grades of disease severity. We describe a patient with the heterozygous LMNA mutation c.1821G>A, leading to neonatal progeria with death in the first year of life. Intracellular lamin A was downregulated in the patient's fibroblasts and the ratio of progerin to lamin A was increased when compared with HGPS. It is suggestive that the ratio of farnesylated protein to mature lamin A determines the disease severity in progeria.
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Affiliation(s)
- Janine Reunert
- Universitätsklinikum Münster, Klinik für Kinder- und Jugendmedizin - Allgemeine Pädiatrie, Münster, Germany
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Kang T, Kwon NH, Lee JY, Park MC, Kang E, Kim HH, Kang TJ, Kim S. AIMP3/p18 controls translational initiation by mediating the delivery of charged initiator tRNA to initiation complex. J Mol Biol 2012; 423:475-81. [PMID: 22867704 DOI: 10.1016/j.jmb.2012.07.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/11/2012] [Accepted: 07/17/2012] [Indexed: 11/28/2022]
Abstract
Aminoacyl-tRNA synthetase-interacting multifunctional proteins (AIMPs) are nonenzymatic scaffolding proteins that comprise multisynthetase complex (MSC) with nine aminoacyl-tRNA synthetases in higher eukaryotes. Among the three AIMPs, AIMP3/p18 is strongly anchored to methionyl-tRNA synthetase (MRS) in the MSC. MRS attaches methionine (Met) to initiator tRNA (tRNA(i)(Met)) and plays an important role in translation initiation. It is known that AIMP3 is dispatched to nucleus or nuclear membrane to induce DNA damage response or senescence; however, the role of AIMP3 in translation as a component of MSC and the meaning of its interaction with MRS are still unclear. Herein, we observed that AIMP3 specifically interacted with Met-tRNA(i)(Met)in vitro, while it showed little or reduced interaction with unacylated or lysine-charged tRNA(i)(Met). In addition, AIMP3 discriminates Met-tRNA(i)(Met) from Met-charged elongator tRNA based on filter-binding assay. Pull-down assay revealed that AIMP3 and MRS had noncompetitive interaction with eukaryotic initiation factor 2 (eIF2) γ subunit (eIF2γ), which is in charge of binding with Met-tRNA(i)(Met) for the delivery of Met-tRNA(i)(Met) to ribosome. AIMP3 recruited active eIF2γ to the MRS-AIMP3 complex, and the level of Met-tRNA(i)(Met) bound to eIF2 complex was reduced by AIMP3 knockdown resulting in reduced protein synthesis. All these results suggested the novel function of AIMP3 as a critical mediator of Met-tRNA(i)(Met) transfer from MRS to eIF2 complex for the accurate and efficient translation initiation.
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Affiliation(s)
- Taehee Kang
- Medicinal Bioconvergence Research Center, Seoul National University, Seoul 151-742, Korea
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Dual role of methionyl-tRNA synthetase in the regulation of translation and tumor suppressor activity of aminoacyl-tRNA synthetase-interacting multifunctional protein-3. Proc Natl Acad Sci U S A 2011; 108:19635-40. [PMID: 22106287 DOI: 10.1073/pnas.1103922108] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mammalian methionyl-tRNA synthetase (MRS) plays an essential role in initiating translation by transferring Met to initiator tRNA (tRNA(i)(Met)). MRS also provides a cytosolic anchoring site for aminoacyl-tRNA synthetase-interacting multifunctional protein-3 (AIMP3)/p18, a potent tumor suppressor that is translocated to the nucleus for DNA repair upon DNA damage. However, the mechanism by which this enzyme mediates these two seemingly unrelated functions is unknown. Here we demonstrate that AIMP3 is released from MRS by UV irradiation-induced stress. Dissociation was induced by phosphorylation of MRS at Ser662 by general control nonrepressed-2 (GCN2) following UV irradiation. Substitution of Ser662 to Asp (S662D) induced a conformational change in MRS and significantly reduced its interaction with AIMP3. This mutant possessed significantly reduced MRS catalytic activity because of loss of tRNA(Met) binding, resulting in down-regulation of global translation. According to the Met incorporation assay using stable HeLa cells expressing MRS S662A or eukaryotic initiation factor-2 subunit-α (eIF2α) S51A, inactivation of GCN2-induced phosphorylation at eIF2α or MRS augmented the role of the other, suggesting a cross-talk between MRS and eIF2α for efficient translational inhibition. This work reveals a unique mode of regulation of global translation as mediated by aminoacyl-tRNA synthetase, specifically MRS, which we herein identified as a previously unidentified GCN2 substrate. In addition, our research suggests a dual role for MRS: (i) as a coregulator with eIF2α for GCN2-mediated translational inhibition; and (ii) as a coupler of translational inhibition and DNA repair following DNA damage by releasing bound tumor suppressor AIMP3 for its nuclear translocation.
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Abstract
Over the past decade, the identification of cancer-associated factors has been a subject of primary interest not only for understanding the basic mechanisms of tumorigenesis but also for discovering the associated therapeutic targets. However, aminoacyl-tRNA synthetases (ARSs) have been overlooked, mostly because many assumed that they were simply 'housekeepers' that were involved in protein synthesis. Mammalian ARSs have evolved many additional domains that are not necessarily linked to their catalytic activities. With these domains, they interact with diverse regulatory factors. In addition, the expression of some ARSs is dynamically changed depending on various cellular types and stresses. This Analysis article addresses the potential pathophysiological implications of ARSs in tumorigenesis.
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Affiliation(s)
- Sunghoon Kim
- Medicinal Bioconvergence Research Center, WCU Department of Molecular Medicine and Biopharmaceutical Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
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