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Klinaki E, Ogrodnik M. In the land of not-unhappiness: On the state-of-the-art of targeting aging and age-related diseases by biomedical research. Mech Ageing Dev 2024; 219:111929. [PMID: 38561164 DOI: 10.1016/j.mad.2024.111929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/12/2024] [Accepted: 03/23/2024] [Indexed: 04/04/2024]
Abstract
The concept of the Land of Not-Unhappiness refers to the potential achievement of eliminating the pathologies of the aging process. To inform of how close we are to settling in the land, we summarize and review the achievements of research on anti-aging interventions over the last hundred years with a specific focus on strategies that slow down metabolism, compensate for aging-related losses, and target a broad range of age-related diseases. We critically evaluate the existing interventions labeled as "anti-aging," such as calorie restriction, exercise, stem cell administration, and senolytics, to provide a down-to-earth evaluation of their current applicability in counteracting aging. Throughout the text, we have maintained a light tone to make it accessible to non-experts in biogerontology, and provide a broad overview for those considering conducting studies, research, or seeking to understand the scientific basis of anti-aging medicine.
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Affiliation(s)
- Eirini Klinaki
- Ludwig Boltzmann Research Group Senescence and Healing of Wounds, Vienna 1200, Austria; Ludwig Boltzmann Institute for Traumatology, The Research Centre in Cooperation with AUVA, Vienna 1200, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Mikolaj Ogrodnik
- Ludwig Boltzmann Research Group Senescence and Healing of Wounds, Vienna 1200, Austria; Ludwig Boltzmann Institute for Traumatology, The Research Centre in Cooperation with AUVA, Vienna 1200, Austria; Austrian Cluster for Tissue Regeneration, Vienna, Austria.
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2
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Alibardi L. Immunolocalization of telomerases in human hairs identifies proliferating cells in the bulb matrix and outer root sheath. Tissue Cell 2024; 88:102344. [PMID: 38513553 DOI: 10.1016/j.tice.2024.102344] [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: 10/22/2023] [Revised: 02/22/2024] [Accepted: 02/29/2024] [Indexed: 03/23/2024]
Abstract
Telomerase is present in cells with numerous or even un-limited replicative cycles, and some studies suggest it is a stemness marker. In order to determine whether this is the case for the human hair bulbs, an immunohistochemical and ultrastructural study has been carried out using antibodies against telomerase and PCNA (a cell proliferation marker). The observed labeling is similar for the two antibodies here utilized and is mainly nuclear. More frequent telomerase-positive cells are seen in the matrix epithelium of anagen hair bulbs but sparse labeled cells are also seen in the outer root sheath. In late catagen and also in telogen hair follicles only sparse labeled cells are present in the outer root sheath and few cells also in the secondary germinal epithelium formed at the base of the hair bulb in telogen. Electron microscopic immunogold shows a prevalent nuclear distribution and a lower cytoplasmic distribution in sparse cells of anagen bulb matrix that contain few keratin bundles. The nuclear localization is generally seen over the euchromatin or in areas occupied by more compact chromatin that may indicate an activity of telomerase in chromatin assemblage or dis-assemblage. The study concludes that the localization of telomerase is present in cells undergoing proliferation, namely transit amplifying cells of the outer root sheath that are sparsely detected in the lowermost secondary germinal hair bulb also in telogen.
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3
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Gao C. Investigating the association between blood metabolites and telomere length: A mendelian randomization study. PLoS One 2024; 19:e0298172. [PMID: 38457472 PMCID: PMC10923442 DOI: 10.1371/journal.pone.0298172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/19/2024] [Indexed: 03/10/2024] Open
Abstract
BACKGROUND Telomere length refers to the protective cap at the end of chromosomes, and it plays a crucial role in many diseases. The objective of this study is to explore the relationship between blood metabolites and telomere length, aiming to identify novel biological factors that influence telomere length. METHODS In this study, we extracted genome-wide association study (GWAS) data for blood metabolites from a sample of 7824 Europeans. Additionally, GWAS data for telomere length were obtained from the Open GWAS database (GWAS ID: ieu-b-4879). The primary analysis of this study utilized the random inverse variance weighted (IVW) method. Complementary analyses were also conducted using the MR-Egger and weighted median approaches. Sensitivity analyses were performed to assess the robustness of the findings. These included the Cochran Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out analysis. To investigate the possibility of reverse causation, reverse MR analysis was conducted. Additionally, multivariable MR was utilized to evaluate the direct effect of metabolites on telomere length. RESULTS The results suggested a potential association between 15-methylpalmitate, taurocholate, levulinate, and X-12712 and telomere length. MVMR analysis further showed that 15-methylpalmitate, taurocholate, and levulinate can directly influence telomere length, regardless of other metabolites. CONCLUSIONS This study suggests that 15-methylpalmitate, taurocholate, and levulinate are likely factors correlated with telomere length. These findings will contribute to the development of strategies for protecting telomeres, preventing related diseases, and establishing a new biological foundation for achieving healthy aging.
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Affiliation(s)
- Chen Gao
- Head and Neck Surgeons, Clinical Oncology School of Fujian Medical University, Fujian Cancer Hospital, Fujian, China
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4
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Gui Q, Ding N, Yao Z, Wu M, Fu R, Wang Y, Zhao Y, Zhu L. Extracellular vesicles derived from mesenchymal stem cells: the wine in Hebe's hands to treat skin aging. PRECISION CLINICAL MEDICINE 2024; 7:pbae004. [PMID: 38516531 PMCID: PMC10955876 DOI: 10.1093/pcmedi/pbae004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 02/22/2024] [Indexed: 03/23/2024] Open
Abstract
Owing to its constant exposure to the external environment and various stimuli, skin ranks among the organs most vulnerable to manifestations of aging. Preventing and delaying skin aging has become one of the prominent research subjects in recent years. Mesenchymal stem cells (MSCs) are multipotent stem cells derived from mesoderm with high self-renewal ability and multilineage differentiation potential. MSC-derived extracellular vesicles (MSC-EVs) are nanoscale biological vesicles that facilitate intercellular communication and regulate biological behavior. Recent studies have shown that MSC-EVs have potential applications in anti-aging therapy due to their anti-inflammatory, anti-oxidative stress, and wound healing promoting abilities. This review presents the latest progress of MSC-EVs in delaying skin aging. It mainly includes the MSC-EVs promoting the proliferation and migration of keratinocytes and fibroblasts, reducing the expression of matrix metalloproteinases, resisting oxidative stress, and regulating inflammation. We then briefly discuss the recently discovered treatment methods of MSC-EVs in the field of skin anti-aging. Moreover, the advantages and limitations of EV-based treatments are also presented.
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Affiliation(s)
- Qixiang Gui
- Department of Plastic and Reconstructive Surgery, Second Affiliated Hospital of Naval Medical University (Shanghai Changzheng Hospital), Shanghai 200001, China
| | - Neng Ding
- Department of Plastic and Reconstructive Surgery, Second Affiliated Hospital of Naval Medical University (Shanghai Changzheng Hospital), Shanghai 200001, China
| | - Zuochao Yao
- Department of Plastic and Reconstructive Surgery of Shanghai East Hospital, School of Medicine, Tongji University, Shanghai 200120, China
| | - Minjuan Wu
- Department of Histology and Embryology, Naval Medical University, Shanghai 200433, China
| | - Ruifeng Fu
- Shanghai Key Laboratory of Cell Engineering, Translational Medical Research Center, Naval Medical University, Shanghai 200433, China
| | - Yue Wang
- Department of Histology and Embryology, Naval Medical University, Shanghai 200433, China
- Shanghai Key Laboratory of Cell Engineering, Translational Medical Research Center, Naval Medical University, Shanghai 200433, China
- Shanghai Institute of Stem Cell Research and Clinical Translation, Shanghai 200092, China
| | - Yunpeng Zhao
- Shanghai Key Laboratory of Cell Engineering, Translational Medical Research Center, Naval Medical University, Shanghai 200433, China
| | - Lie Zhu
- Department of Plastic and Reconstructive Surgery, Second Affiliated Hospital of Naval Medical University (Shanghai Changzheng Hospital), Shanghai 200001, China
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5
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Lorbeer FK, Rieser G, Goel A, Wang M, Oh A, Yeh I, Bastian BC, Hockemeyer D. Distinct senescence mechanisms restrain progression of dysplastic nevi. PNAS NEXUS 2024; 3:pgae041. [PMID: 38371417 PMCID: PMC10873501 DOI: 10.1093/pnasnexus/pgae041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 01/16/2024] [Indexed: 02/20/2024]
Abstract
Telomerase reverse transcriptase (TERT) promoter mutations (TPMs) are frequently found in different cancer types, including ∼70% of sun-exposed skin melanomas. In melanoma, TPMs are among the earliest mutations and can be present during the transition from nevus to melanoma. However, the specific factors that contribute to the selection of TPMs in certain nevi subsets are not well understood. To investigate this, we analyzed a group of dysplastic nevi (DN) by sequencing genes commonly mutated in melanocytic neoplasms. We examined the relationship between the identified mutations, patient age, telomere length, histological features, and the expression of p16. Our findings reveal that TPMs are more prevalent in DN from older patients and are associated with shorter telomeres. Importantly, these TPMs were not found in nevi with BRAF V600E mutations. Conversely, DN with BRAF V600E mutations were observed in younger patients, had longer telomeres and a higher proportion of p16-positive cells. This suggests that these nevi arrest growth independently of telomere shortening through a mechanism known as oncogene-induced senescence (OIS). These characteristics extend to melanoma-sequencing datasets, where melanomas with BRAF V600E mutations were more likely to have a CDKN2A inactivation, overriding OIS. In contrast, melanomas without BRAF V600E mutations showed a higher frequency of TPMs. Our data imply that TPMs are selected to bypass replicative senescence (RS) in cells that were not arrested by OIS. Overall, our results indicate that a subset of melanocytic neoplasms face constraints from RS, while others encounter OIS and RS. The order in which these barriers are overcome during progression to melanoma depends on the mutational context.
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Affiliation(s)
- Franziska K Lorbeer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Gabrielle Rieser
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Aditya Goel
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Meng Wang
- Department of Dermatology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Areum Oh
- Rebus Biosystems, Santa Clara, CA 95050, USA
| | - Iwei Yeh
- Department of Dermatology, University of California, San Francisco, San Francisco, CA 94143, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Boris C Bastian
- Department of Dermatology, University of California, San Francisco, San Francisco, CA 94143, USA
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
- Innovative Genomics Institute, University of California, Berkeley, CA 94720, USA
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6
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Jin S, Li K, Zong X, Eun S, Morimoto N, Guo S. Hallmarks of Skin Aging: Update. Aging Dis 2023; 14:2167-2176. [PMID: 37199583 PMCID: PMC10676801 DOI: 10.14336/ad.2023.0321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/21/2023] [Indexed: 05/19/2023] Open
Abstract
Aging is defined as impaired physiological integrity, decreased function, increased susceptibility to external risk factors and various diseases. Skin, the largest organ in our body, may become more vulnerable to insult as time goes by and behave as aged skin. Here, we systemically reviewed three categories including seven hallmarks of skin aging. These hallmarks including genomic instability and telomere attrition, epigenetic alterations and loss of proteostasis, deregulated nutrient-sensing, mitochondrial damage and dysfunction, cellular senescence, stem cell exhaustion/dysregulation, and altered intercellular communication. These seven hallmarks can generally be divided into three categories including (i) causes of damages as primary hallmarks in skin aging; (ii) responses to damage as antagonistic hallmarks in skin aging; and (iii) culprits of the phenotype as integrative hallmarks in skin aging.
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Affiliation(s)
- Shifeng Jin
- Department of Plastic Surgery, the First Hospital of China Medical University, Liaoning, China.
| | - Kezhu Li
- Department of Plastic Surgery, the First Hospital of China Medical University, Liaoning, China.
| | - Xuanru Zong
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Shandong, China.
| | - Seokchan Eun
- Department of Plastic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 463-707, Korea.
| | - Naoki Morimoto
- Department of Plastic Reconstructive Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
| | - Shu Guo
- Department of Plastic Surgery, the First Hospital of China Medical University, Liaoning, China.
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7
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Lorbeer FK, Rieser G, Goel A, Wang M, Oh A, Yeh I, Bastian BC, Hockemeyer D. Distinct senescence mechanisms restrain progression of dysplastic nevi. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.14.548818. [PMID: 37503286 PMCID: PMC10369942 DOI: 10.1101/2023.07.14.548818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
TERT promoter mutations (TPMs) are frequently found in different cancer types, including approximately 70% of sun-exposed skin melanomas. In melanoma, TPMs are among the earliest mutations and can be present during the transition from nevus to melanoma. However, the specific factors that contribute to the selection of TPMs in certain nevi subsets are not well understood. To investigate this, we analyzed a group of dysplastic nevi (DN) by sequencing genes commonly mutated in melanocytic neoplasms. We examined the relationship between the identified mutations, patient age, telomere length, histological features, and the expression of p16. Our findings reveal that TPMs are more prevalent in DN from older patients and are associated with shorter telomeres. Importantly, these TPMs were not found in nevi with BRAF V600E mutations. Conversely, DN with BRAF V600E mutations were observed in younger patients, had longer telomeres, and a higher proportion of p16-positive cells. This suggests that these nevi arrest growth independently of telomere shortening through a mechanism known as oncogene-induced senescence (OIS). These characteristics extend to melanoma sequencing data sets, where melanomas with BRAF V600E mutations were more likely to have CDKN2A inactivation, overriding OIS. In contrast, melanomas without BRAF V600E mutations showed a higher frequency of TPMs. Our data imply that TPMs are selected to bypass replicative senescence (RS) in cells that were not arrested by OIS. Overall, our results indicate that a subset of melanocytic neoplasms face constraints from RS, while others encounter OIS and RS. The order in which these barriers are overcome during progression to melanoma depends on the mutational context.
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8
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Liu X, Khalil AEMM, Muthukumarasamy U, Onogi Y, Yan X, Singh I, Lopez-Gonzales E, Israel A, Serrano AC, Strowig T, Ussar S. Reduced intestinal lipid absorption improves glucose metabolism in aged G2-Terc knockout mice. BMC Biol 2023; 21:150. [PMID: 37403071 DOI: 10.1186/s12915-023-01629-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 05/22/2023] [Indexed: 07/06/2023] Open
Abstract
BACKGROUND Biological aging is an important factor leading to the development of pathologies associated with metabolic dysregulation, including type 2 diabetes, cancer, cardiovascular and neurodegenerative diseases. Telomere length, a central feature of aging, has additionally been identified as inversely associated with glucose tolerance and the development of type 2 diabetes. However, the effects of shortened telomeres on body weight and metabolism remain incompletely understood. Here, we studied the metabolic consequences of moderate telomere shortening using second generation loss of telomerase activity in mice. RESULTS Aged male and female G2 Terc-/- mice and controls were characterized with respect to body weight and composition, glucose homeostasis, insulin sensitivity and metabolic activity. This was complemented with molecular and histological analysis of adipose tissue, liver and the intestine as well as microbiota analysis. We show that moderate telomere shortening leads to improved insulin sensitivity and glucose tolerance in aged male and female G2 Terc-/- mice. This is accompanied by reduced fat and lean mass in both sexes. Mechanistically, the metabolic improvement results from reduced dietary lipid uptake in the intestine, characterized by reduced gene expression of fatty acid transporters in enterocytes of the small intestine. Furthermore, G2-Terc-/- mice showed significant alterations in the composition of gut microbiota, potentially contributing to the improved glucose metabolism. CONCLUSIONS Our study shows that moderate telomere shortening reduces intestinal lipid absorption, resulting in reduced adiposity and improved glucose metabolism in aged mice. These findings will guide future murine and human aging studies and provide important insights into the age associated development of type 2 diabetes and metabolic syndrome.
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Affiliation(s)
- Xue Liu
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Ahmed Elagamy Mohamed Mahmoud Khalil
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | | | - Yasuhiro Onogi
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Xiaocheng Yan
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Inderjeet Singh
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Elena Lopez-Gonzales
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Andreas Israel
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
| | - Alberto Cebrian Serrano
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany
- Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany
| | - Till Strowig
- Microbial Immune Regulation Research Group, Helmholtz Centre for Infection Research, Brunswick, Germany
- Hannover Medical School, Hannover, Germany
| | - Siegfried Ussar
- RG Adipocytes & Metabolism, Institute for Diabetes & Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany.
- Department of Medicine, Technische Universität München, Munich, Germany.
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Polonio AM, Medrano M, Chico-Sordo L, Córdova-Oriz I, Cozzolino M, Montans J, Herraiz S, Seli E, Pellicer A, García-Velasco JA, Varela E. Impaired telomere pathway and fertility in Senescence-Accelerated Mice Prone 8 females with reproductive senescence. Aging (Albany NY) 2023; 15:4600-4624. [PMID: 37338562 DOI: 10.18632/aging.204731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/04/2023] [Indexed: 06/21/2023]
Abstract
Ovarian aging is the main cause of infertility and telomere attrition is common to both aging and fertility disorders. Senescence-Accelerated Mouse Prone 8 (SAMP8) model has shortened lifespan and premature infertility, reflecting signs of reproductive senescence described in middle-aged women. Thus, our objective was to study SAMP8 female fertility and the telomere pathway at the point of reproductive senescence. The lifespan of SAMP8 and control mice was monitored. Telomere length (TL) was measured by in situ hybridization in blood and ovary. Telomerase activity (TA) was analyzed by telomere-repeat amplification protocol, and telomerase expression, by real-time quantitative PCR in ovaries from 7-month-old SAMP8 and controls. Ovarian follicles at different stages of maturation were evaluated by immunohistochemistry. Reproductive outcomes were analyzed after ovarian stimulation. Unpaired t-test or Mann-Whitney test were used to calculate p-values, depending on the variable distribution. Long-rank test was used to compare survival curves and Fisher's exact test was used in contingency tables. Median lifespan of SAMP8 females was reduced compared to SAMP8 males (p = 0.0138) and control females (p < 0.0001). In blood, 7-month-old SAMP8 females presented lower mean TL compared to age-matched controls (p = 0.041). Accordingly, the accumulation of short telomeres was higher in 7-month-old SAMP8 females (p = 0.0202). Ovarian TA was lower in 7-month-old SAMP8 females compared to controls. Similarly, telomerase expression was lower in the ovaries of 7-month-old SAMP8 females (p = 0.04). Globally, mean TL in ovaries and granulosa cells (GCs) were similar. However, the percentage of long telomeres in ovaries (p = 0.004) and GCs (p = 0.004) from 7-month-old SAMP8 females was lower compared to controls. In early-antral and antral follicles, mean TL of SAMP8 GCs was lower than in age-matched controls (p = 0.0156 for early-antral and p = 0.0037 for antral follicles). Middle-aged SAMP8 showed similar numbers of follicles than controls, although recovered oocytes after ovarian stimulation were lower (p = 0.0068). Fertilization rate in oocytes from SAMP8 was not impaired, but SAMP8 mice produced significantly more morphologically abnormal embryos than controls (27.03% in SAMP8 vs. 1.22% in controls; p < 0.001). Our findings suggest telomere dysfunction in SAMP8 females, at the time of reproductive senescence.
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Affiliation(s)
- Alba M Polonio
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Marta Medrano
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Lucía Chico-Sordo
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Isabel Córdova-Oriz
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | | | | | - Sonia Herraiz
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
| | - Emre Seli
- IVIRMA New Jersey, Basking Ridge, NJ 07920, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale School of Medicine, New Heaven, CT 06510, USA
| | - Antonio Pellicer
- IVIRMA Rome, Rome, Italy
- Department of Pediatrics, Obstetrics and Gynecology, University of Valencia, Valencia, Spain
| | - Juan A García-Velasco
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
- IVIRMA Madrid, Madrid, Spain
- Department of Obstetrics and Gynecology, Rey Juan Carlos University, Madrid, Spain
| | - Elisa Varela
- IVI Foundation, The Health Research Institute La Fe (IIS La Fe), Valencia, Spain
- Department of Obstetrics and Gynecology, Rey Juan Carlos University, Madrid, Spain
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10
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Li S, Liu Z, Zhang J, Li L. Links between telomere dysfunction and hallmarks of aging. MUTATION RESEARCH/GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2023; 888:503617. [PMID: 37188431 DOI: 10.1016/j.mrgentox.2023.503617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/10/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023]
Abstract
Aging is characterized by the gradual loss of physiological integrity, leading to impaired function and increased risk of death. This deterioration is the main risk factor for the great majority of chronic diseases, which account for most of the morbidity, death and medical expenses. The hallmarks of aging comprise diverse molecular mechanisms and cell systems, which are interrelated and coordinated to drive the aging process. This review focuses on telomere to analyze the interrelationships between telomere dysfunction and other aging hallmarks and their relative contributions to the initiation and progression of age-related diseases (such as neurodegeneration, cardiovascular disease, and cancer), which will contribute to determine drug targets, improve human health in the aging process with minimal side effects and provide information for the prevention and treatment of age-related diseases.
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11
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Liu LP, Li MH, Zheng YW. Hair Follicles as a Critical Model for Monitoring the Circadian Clock. Int J Mol Sci 2023; 24:ijms24032407. [PMID: 36768730 PMCID: PMC9916850 DOI: 10.3390/ijms24032407] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/30/2022] [Accepted: 01/20/2023] [Indexed: 01/27/2023] Open
Abstract
Clock (circadian) genes are heterogeneously expressed in hair follicles (HFs). The genes can be modulated by both the central circadian system and some extrinsic factors, such as light and thyroid hormones. These circadian genes participate in the regulation of several physiological processes of HFs, including hair growth and pigmentation. On the other hand, because peripheral circadian genes are synchronized with the central clock, HFs could provide a noninvasive and practical method for monitoring and evaluating multiple circadian-rhythm-related conditions and disorders among humans, including day and night shifts, sleep-wake disorders, physical activities, energy metabolism, and aging. However, due to the complexity of circadian biology, understanding how intrinsic oscillation operates using peripheral tissues only may be insufficient. Combining HF sampling with multidimensional assays such as detection of body temperature, blood samples, or certain validated questionnaires may be helpful in improving HF applications. Thus, HFs can serve as a critical model for monitoring the circadian clock and can help provide an understanding of the potential mechanisms of circadian-rhythm-related conditions; furthermore, chronotherapy could support personalized treatment scheduling based on the gene expression profile expressed in HFs.
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Affiliation(s)
- Li-Ping Liu
- Department of Dermatology, Affiliated Hospital of Jiangsu University, Zhenjiang 212001, China
- Institute of Regenerative Medicine, Jiangsu University, Zhenjiang 212001, China
- Correspondence: (L.-P.L.); (Y.-W.Z.)
| | - Meng-Huan Li
- Department of Dermatology, Affiliated Hospital of Jiangsu University, Zhenjiang 212001, China
- Institute of Regenerative Medicine, Jiangsu University, Zhenjiang 212001, China
| | - Yun-Wen Zheng
- Institute of Regenerative Medicine, Jiangsu University, Zhenjiang 212001, China
- Guangdong Provincial Key Laboratory of Large Animal Models for Biomedicine, South China Institute of Large Animal Models for Biomedicine, School of Biotechnology and Health Sciences, Wuyi University, Jiangmen 529020, China
- Department of Medicinal and Life Sciences, Faculty of Pharmaceutical Sciences, Tokyo University of Science, Noda 278-8510, Japan
- Department of Regenerative Medicine, Yokohama City University School of Medicine, Yokohama 234-0006, Japan
- Division of Regenerative Medicine, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
- Correspondence: (L.-P.L.); (Y.-W.Z.)
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12
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Gao J, Pickett HA. Targeting telomeres: advances in telomere maintenance mechanism-specific cancer therapies. Nat Rev Cancer 2022; 22:515-532. [PMID: 35790854 DOI: 10.1038/s41568-022-00490-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/25/2022] [Indexed: 12/31/2022]
Abstract
Cancer cells establish replicative immortality by activating a telomere-maintenance mechanism (TMM), be it telomerase or the alternative lengthening of telomeres (ALT) pathway. Targeting telomere maintenance represents an intriguing opportunity to treat the vast majority of all cancer types. Whilst telomerase inhibitors have historically been heralded as promising anticancer agents, the reality has been more challenging, and there are currently no therapeutic options for cancer types that use ALT despite their aggressive nature and poor prognosis. In this Review, we discuss the mechanistic differences between telomere maintenance by telomerase and ALT, the current methods used to detect each mechanism, the utility of these tests for clinical diagnosis, and recent developments in the therapeutic strategies being employed to target both telomerase and ALT. We present notable developments in repurposing established therapeutic agents and new avenues that are emerging to target cancer types according to which TMM they employ. These opportunities extend beyond inhibition of telomere maintenance, by finding and exploiting inherent weaknesses in the telomeres themselves to trigger rapid cellular effects that lead to cell death.
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Affiliation(s)
- Jixuan Gao
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW, Australia.
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13
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Choo S, Lorbeer FK, Regalado SG, Short SB, Wu S, Rieser G, Bertuch AA, Hockemeyer D. Editing TINF2 as a potential therapeutic approach to restore telomere length in dyskeratosis congenita. Blood 2022; 140:608-618. [PMID: 35421215 PMCID: PMC9373014 DOI: 10.1182/blood.2021013750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/25/2022] [Indexed: 11/29/2022] Open
Abstract
Mutations in the TINF2 gene, encoding the shelterin protein TIN2, cause telomere shortening and the inherited bone marrow (BM) failure syndrome dyskeratosis congenita (DC). A lack of suitable model systems limits the mechanistic understanding of telomere shortening in the stem cells and thus hinders the development of treatment options for BM failure. Here, we endogenously introduced TIN2-DC mutations in human embryonic stem cells (hESCs) and human hematopoietic stem and progenitor cells (HSPCs) to dissect the disease mechanism and identify a gene-editing strategy that rescued the disease phenotypes. The hESCs with the T284R disease mutation exhibited the short telomere phenotype observed in DC patients. Yet, telomeres in mutant hESCs did not trigger DNA damage responses at telomeres or show exacerbated telomere shortening when differentiated into telomerase-negative cells. Disruption of the mutant TINF2 allele by introducing a frameshift mutation in exon 2 restored telomere length in stem cells and the replicative potential of differentiated cells. Similarly, we introduced TIN2-DC disease variants in human HSPCs to assess the changes in telomere length and proliferative capacity. Lastly, we showed that editing at exon 2 of TINF2 that restored telomere length in hESCs could be generated in TINF2-DC patient HSPCs. Our study demonstrates a simple genetic intervention that rescues the TIN2-DC disease phenotype in stem cells and provides a versatile platform to assess the efficacy of potential therapeutic approaches in vivo.
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Affiliation(s)
- Seunga Choo
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Franziska K Lorbeer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Samuel G Regalado
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Sarah B Short
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Shannon Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Gabrielle Rieser
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Alison A Bertuch
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
- Chan Zuckerberg Biohub, San Francisco, CA; and
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA
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14
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Lyu Y, Ge Y. Toward Elucidating Epigenetic and Metabolic Regulation of Stem Cell Lineage Plasticity in Skin Aging. Front Cell Dev Biol 2022; 10:903904. [PMID: 35663405 PMCID: PMC9160930 DOI: 10.3389/fcell.2022.903904] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Skin is the largest organ in human body, harboring a plethora of cell types and serving as the organismal barrier. Skin aging such as wrinkling and hair graying is graphically pronounced, and the molecular mechanisms behind these phenotypic manifestations are beginning to unfold. As in many other organs and tissues, epigenetic and metabolic deregulations have emerged as key aging drivers. Particularly in the context of the skin epithelium, the epigenome and metabolome coordinately shape lineage plasticity and orchestrate stem cell function during aging. Our review discusses recent studies that proposed molecular mechanisms that drive the degeneration of hair follicles, a major appendage of the skin. By focusing on skin while comparing it to model organisms and adult stem cells of other tissues, we summarize literature on genotoxic stress, nutritional sensing, metabolic rewiring, mitochondrial activity, and epigenetic regulations of stem cell plasticity. Finally, we speculate about the rejuvenation potential of rate-limiting upstream signals during aging and the dominant role of the tissue microenvironment in dictating aged epithelial stem cell function.
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Affiliation(s)
| | - Yejing Ge
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
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15
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Momeni-Boroujeni A, Yousefi E, Gupta S, Benayed R, Berger MF, Ladanyi M, Monroe R, Kim J, Jungbluth A, Weigelt B, Park KJ. Evaluation of TERT mRNA expression using RNAscope®: A potential histopathologic diagnostic and prognostic tool. Pathol Res Pract 2022; 233:153892. [DOI: 10.1016/j.prp.2022.153892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/07/2022] [Indexed: 11/29/2022]
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16
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Effect of oxidative stress on telomere maintenance in aortic smooth muscle cells. Biochim Biophys Acta Mol Basis Dis 2022; 1868:166397. [PMID: 35346819 DOI: 10.1016/j.bbadis.2022.166397] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 03/11/2022] [Accepted: 03/14/2022] [Indexed: 12/12/2022]
Abstract
Reactive oxygen species (ROS) and telomere dysfunction are both associated with aging and the development of age-related diseases. Although there is evidence for a direct relationship between ROS and telomere dysfunction as well as an independent association of oxidative stress and telomere attrition with age-related disorders, there has not been sufficient exploration of how the interaction between oxidative stress and telomere function may contribute to the pathophysiology of cardiovascular diseases (CVD). To better understand the complex relationships between oxidative stress, telomerase biology and pathophysiology, we examined the telomere biology of aortic smooth muscle cells (ASMCs) isolated from mutant mouse models of oxidative stress. We discovered that telomere lengths were significantly shorter in ASMCs isolated from superoxide dismutase 2 heterozygous (Sod2+/-) mice, which exhibit increased arterial stiffness with aging, and the observed telomere attrition occurred over time. Furthermore, the telomere erosion occurred even though telomerase activity increased. In contrast, telomeres remained stable in wild-type and superoxide dismutase 1 heterozygous (Sod1+/-) mice, which do not exhibit CVD phenotypes. The data indicate that mitochondrial oxidative stress, in particular elevated superoxide levels and decreased hydrogen peroxide levels, induces telomere erosion in the ASMCs of the Sod2+/- mice. This reduction in telomere length occurs despite an increase in telomerase activity and correlates with the onset of disease phenotype. Our results suggest that the oxidative stress caused by imbalance in mitochondrial ROS, from deficient SOD2 activity as a model for mitochondrial dysfunction results in telomere dysfunction, which may contribute to pathogenesis of CVD.
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17
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De Sanctis F, Lamolinara A, Boschi F, Musiu C, Caligola S, Trovato R, Fiore A, Frusteri C, Anselmi C, Poffe O, Cestari T, Canè S, Sartoris S, Giugno R, Del Rosario G, Zappacosta B, Del Pizzo F, Fassan M, Dugnani E, Piemonti L, Bottani E, Decimo I, Paiella S, Salvia R, Lawlor RT, Corbo V, Park Y, Tuveson DA, Bassi C, Scarpa A, Iezzi M, Ugel S, Bronte V. Interrupting the nitrosative stress fuels tumor-specific cytotoxic T lymphocytes in pancreatic cancer. J Immunother Cancer 2022; 10:jitc-2021-003549. [PMID: 35022194 PMCID: PMC8756272 DOI: 10.1136/jitc-2021-003549] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2021] [Indexed: 12/11/2022] Open
Abstract
Background Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors owing to its robust desmoplasia, low immunogenicity, and recruitment of cancer-conditioned, immunoregulatory myeloid cells. These features strongly limit the success of immunotherapy as a single agent, thereby suggesting the need for the development of a multitargeted approach. The goal is to foster T lymphocyte infiltration within the tumor landscape and neutralize cancer-triggered immune suppression, to enhance the therapeutic effectiveness of immune-based treatments, such as anticancer adoptive cell therapy (ACT). Methods We examined the contribution of immunosuppressive myeloid cells expressing arginase 1 and nitric oxide synthase 2 in building up a reactive nitrogen species (RNS)-dependent chemical barrier and shaping the PDAC immune landscape. We examined the impact of pharmacological RNS interference on overcoming the recruitment and immunosuppressive activity of tumor-expanded myeloid cells, which render pancreatic cancers resistant to immunotherapy. Results PDAC progression is marked by a stepwise infiltration of myeloid cells, which enforces a highly immunosuppressive microenvironment through the uncontrolled metabolism of L-arginine by arginase 1 and inducible nitric oxide synthase activity, resulting in the production of large amounts of reactive oxygen and nitrogen species. The extensive accumulation of myeloid suppressing cells and nitrated tyrosines (nitrotyrosine, N-Ty) establishes an RNS-dependent chemical barrier that impairs tumor infiltration by T lymphocytes and restricts the efficacy of adoptive immunotherapy. A pharmacological treatment with AT38 ([3-(aminocarbonyl)furoxan-4-yl]methyl salicylate) reprograms the tumor microenvironment from protumoral to antitumoral, which supports T lymphocyte entrance within the tumor core and aids the efficacy of ACT with telomerase-specific cytotoxic T lymphocytes. Conclusions Tumor microenvironment reprogramming by ablating aberrant RNS production bypasses the current limits of immunotherapy in PDAC by overcoming immune resistance.
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Affiliation(s)
- Francesco De Sanctis
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Alessia Lamolinara
- Department of Neurosciences, Imaging and Clinical Sciences, Center for Advanced Studies and Technnology (CAST), G. d'Annunzio University of Chieti Pescara, Chieti, Italy
| | - Federico Boschi
- Department of Computer Science, University of Verona, Verona, Italy
| | - Chiara Musiu
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Simone Caligola
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Rosalinda Trovato
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Alessandra Fiore
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Cristina Frusteri
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Cristina Anselmi
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Ornella Poffe
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Tiziana Cestari
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Stefania Canè
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Silvia Sartoris
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Rosalba Giugno
- Department of Computer Science, University of Verona, Verona, Italy
| | | | | | - Francesco Del Pizzo
- Department of Neurosciences, Imaging and Clinical Sciences, Center for Advanced Studies and Technnology (CAST), G. d'Annunzio University of Chieti Pescara, Chieti, Italy
| | - Matteo Fassan
- Department of Medicine, University of Padua, Padova, Italy.,Veneto Institute of Oncology-Institute for Hospitalization and Care Scientific, Padova, Italy
| | - Erica Dugnani
- Diabetes Research Institute, San Raffaele Research Centre, Milano, Italy
| | - Lorenzo Piemonti
- Diabetes Research Institute, San Raffaele Research Centre, Milano, Italy.,School of Medicine and Surgery, Vita-Salute San Raffaele University, Milano, Italy
| | - Emanuela Bottani
- Department of Diagnostic and Public Health, Section of Pharmacology, University of Verona, Verona, Italy
| | - Ilaria Decimo
- Department of Diagnostic and Public Health, Section of Pharmacology, University of Verona, Verona, Italy
| | - Salvatore Paiella
- General and Pancreatic Surgery Unit, University of Verona, Verona, Italy
| | - Roberto Salvia
- General and Pancreatic Surgery Unit, University of Verona, Verona, Italy
| | | | - Vincenzo Corbo
- ARC-NET, University of Verona, Verona, Italy.,Department of Diagnostic and Public Health, University of Verona, Verona, Italy
| | - Youngkyu Park
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.,Pancreatic Cancer Research Laboratory, Lustgarten Foundation, Cold Spring Harbor, New York, USA
| | - David A Tuveson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.,Pancreatic Cancer Research Laboratory, Lustgarten Foundation, Cold Spring Harbor, New York, USA
| | - Claudio Bassi
- General and Pancreatic Surgery Unit, University of Verona, Verona, Italy
| | - Aldo Scarpa
- ARC-NET, University of Verona, Verona, Italy.,Department of Diagnostic and Public Health, University of Verona, Verona, Italy
| | - Manuela Iezzi
- Department of Neurosciences, Imaging and Clinical Sciences, Center for Advanced Studies and Technnology (CAST), G. d'Annunzio University of Chieti Pescara, Chieti, Italy
| | - Stefano Ugel
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
| | - Vincenzo Bronte
- Department of Medicine, Section of Immunology, University of Verona, Verona, Italy
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18
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Thongon N, Ma F, Santoni A, Marchesini M, Fiorini E, Rose A, Adema V, Ganan-Gomez I, Groarke EM, Gutierrez-Rodrigues F, Chen S, Lockyer P, Schneider S, Bueso-Ramos C, Montalban-Bravo G, Class CA, Soltysiak KA, Pellegrini M, Sahin E, Bertuch AA, DiNardo CD, Garcia-Manero G, Young NS, Dwyer K, Colla S. Hematopoiesis under telomere attrition at the single-cell resolution. Nat Commun 2021; 12:6850. [PMID: 34824242 PMCID: PMC8617077 DOI: 10.1038/s41467-021-27206-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/08/2021] [Indexed: 11/15/2022] Open
Abstract
The molecular mechanisms that drive hematopoietic stem cell functional decline under conditions of telomere shortening are not completely understood. In light of recent advances in single-cell technologies, we sought to redefine the transcriptional and epigenetic landscape of mouse and human hematopoietic stem cells under telomere attrition, as induced by pathogenic germline variants in telomerase complex genes. Here, we show that telomere attrition maintains hematopoietic stem cells under persistent metabolic activation and differentiation towards the megakaryocytic lineage through the cell-intrinsic upregulation of the innate immune signaling response, which directly compromises hematopoietic stem cells' self-renewal capabilities and eventually leads to their exhaustion. Mechanistically, we demonstrate that targeting members of the Ifi20x/IFI16 family of cytosolic DNA sensors using the oligodeoxynucleotide A151, which comprises four repeats of the TTAGGG motif of the telomeric DNA, overcomes interferon signaling activation in telomere-dysfunctional hematopoietic stem cells and these cells' skewed differentiation towards the megakaryocytic lineage. This study challenges the historical hypothesis that telomere attrition limits the proliferative potential of hematopoietic stem cells by inducing apoptosis, autophagy, or senescence, and suggests that targeting IFI16 signaling axis might prevent hematopoietic stem cell functional decline in conditions affecting telomere maintenance.
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Affiliation(s)
- Natthakan Thongon
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Feiyang Ma
- Division of Rheumatology, Department of Internal Medicine, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Andrea Santoni
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Matteo Marchesini
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori", Meldola, Italy
| | - Elena Fiorini
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ashley Rose
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Vera Adema
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Irene Ganan-Gomez
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Emma M Groarke
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Shuaitong Chen
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Pamela Lockyer
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sarah Schneider
- Department of Stem Cell Transplantation and Hematopoietic Biology and Malignancy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Carlos Bueso-Ramos
- Department of Hematopathology, The University of Texas MD Cancer Center, Houston, TX, USA
| | | | - Caleb A Class
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Butler University, Indianapolis, IN, USA
| | - Kelly A Soltysiak
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Matteo Pellegrini
- Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
| | - Ergun Sahin
- Huffington Center On Aging, Baylor College of Medicine, Houston, TX, USA
| | - Alison A Bertuch
- Department of Pediatrics and Molecular & Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Courtney D DiNardo
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Neal S Young
- Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Karen Dwyer
- Department of Stem Cell Transplantation and Hematopoietic Biology and Malignancy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Simona Colla
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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19
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Low E, Alimohammadiha G, Smith LA, Costello LF, Przyborski SA, von Zglinicki T, Miwa S. How good is the evidence that cellular senescence causes skin ageing? Ageing Res Rev 2021; 71:101456. [PMID: 34487917 PMCID: PMC8524668 DOI: 10.1016/j.arr.2021.101456] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/25/2021] [Accepted: 08/31/2021] [Indexed: 12/11/2022]
Abstract
Skin is the largest organ of the body with important protective functions, which become compromised with time due to both intrinsic and extrinsic ageing processes. Cellular senescence is the primary ageing process at cell level, associated with loss of proliferative capacity, mitochondrial dysfunction and significantly altered patterns of expression and secretion of bioactive molecules. Intervention experiments have proven cell senescence as a relevant cause of ageing in many organs. In case of skin, accumulation of senescence in all major compartments with ageing is well documented and might be responsible for most, if not all, the molecular changes observed during ageing. Incorporation of senescent cells into in-vitro skin models (specifically 3D full thickness models) recapitulates changes typically associated with skin ageing. However, crucial evidence is still missing. A beneficial effect of senescent cell ablation on skin ageing has so far only been shown following rather unspecific interventions or in transgenic mouse models. We conclude that evidence for cellular senescence as a relevant cause of intrinsic skin ageing is highly suggestive but not yet completely conclusive.
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Affiliation(s)
- Evon Low
- Ageing Biology Laboratories, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
| | - Ghazaleh Alimohammadiha
- Ageing Biology Laboratories, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
| | - Lucy A Smith
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Lydia F Costello
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Stefan A Przyborski
- Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK
| | - Thomas von Zglinicki
- Ageing Biology Laboratories, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE4 5PL, UK.
| | - Satomi Miwa
- Ageing Biology Laboratories, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne NE4 5PL, UK
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20
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Epigenetic features in regulation of telomeres and telomerase in stem cells. Emerg Top Life Sci 2021; 5:497-505. [PMID: 34486664 DOI: 10.1042/etls20200344] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 07/28/2021] [Accepted: 08/10/2021] [Indexed: 01/12/2023]
Abstract
The epigenetic nature of telomeres is still controversial and different human cell lines might show diverse histone marks at telomeres. Epigenetic modifications regulate telomere length and telomerase activity that influence telomere structure and maintenance. Telomerase is responsible for telomere elongation and maintenance and is minimally composed of the catalytic protein component, telomerase reverse transcriptase (TERT) and template forming RNA component, telomerase RNA (TERC). TERT promoter mutations may underpin some telomerase activation but regulation of the gene is not completely understood due to the complex interplay of epigenetic, transcriptional, and posttranscriptional modifications. Pluripotent stem cells (PSCs) can maintain an indefinite, immortal, proliferation potential through their endogenous telomerase activity, maintenance of telomere length, and a bypass of replicative senescence in vitro. Differentiation of PSCs results in silencing of the TERT gene and an overall reversion to a mortal, somatic cell phenotype. The precise mechanisms for this controlled transcriptional silencing are complex. Promoter methylation has been suggested to be associated with epigenetic control of telomerase regulation which presents an important prospect for understanding cancer and stem cell biology. Control of down-regulation of telomerase during differentiation of PSCs provides a convenient model for the study of its endogenous regulation. Telomerase reactivation has the potential to reverse tissue degeneration, drive repair, and form a component of future tissue engineering strategies. Taken together it becomes clear that PSCs provide a unique system to understand telomerase regulation fully and drive this knowledge forward into aging and therapeutic application.
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21
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Dolejs J, Homolková H. Why Does Child Mortality Decrease With Age? Modeling the Age-Associated Decrease in Mortality Rate Using WHO Metadata From 25 Countries. Front Pediatr 2021; 9:657298. [PMID: 34458207 PMCID: PMC8387124 DOI: 10.3389/fped.2021.657298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 07/06/2021] [Indexed: 11/23/2022] Open
Abstract
Background: Our previous study analyzed the age trajectory of mortality (ATM) in 14 European countries, while this study aimed at investigating ATM in other continents and in countries with a higher level of mortality. Data from 11 Non-European countries were used. Methods: The number of deaths was extracted from the WHO mortality database. The Halley method was used to calculate the mortality rates in all possible calendar years and all countries combined. This method enables us to combine more countries and more calendar years in one hypothetical population. Results: The age trajectory of total mortality (ATTM) and also ATM due to specific groups of diseases were very similar in the 11 non-European countries and in the 14 European countries. The level of mortality did not affect the main results found in European countries. The inverse proportion was valid for ATTM in non-European countries with two exceptions. Slower or no mortality decrease with age was detected in the first year of life, while the inverse proportion model was valid for the age range (1, 10) years in most of the main chapters of ICD10. Conclusions: The decrease in child mortality with age may be explained as the result of the depletion of individuals with congenital impairment. The majority of deaths up to the age of 10 years were related to congenital impairments, and the decrease in child mortality rate with age was a demonstration of population heterogeneity. The congenital impairments were latent and may cause death even if no congenital impairment was detected.
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Affiliation(s)
- Josef Dolejs
- Department of Informatics and Quantitative Methods, University of Hradec Králové, Hradec Králové, Czechia
| | - Helena Homolková
- Division of Pediatric Neurosurgery, Department of Pediatric and Trauma Surgery, Thomayer's Teaching Hospital and Third Faculty of Medicine, Charles University in Prague, Prague, Czechia
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22
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How DNA damage and non-canonical nucleotides alter the telomerase catalytic cycle. DNA Repair (Amst) 2021; 107:103198. [PMID: 34371388 DOI: 10.1016/j.dnarep.2021.103198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/01/2023]
Abstract
Telomeres at the ends of linear chromosomes are essential for genome maintenance and sustained cellular proliferation, but shorten with each cell division. Telomerase, a specialized reverse transcriptase with its own integral RNA template, compensates for this by lengthening the telomeric 3' single strand overhang. Mammalian telomerase has the unique ability to processively synthesize multiple GGTTAG repeats, by translocating along its product and reiteratively copying the RNA template, termed repeat addition processivity (RAP). This unusual form of processivity is distinct from the nucleotide addition processivity (NAP) shared by all other DNA polymerases. In this review, we focus on the minimally active human telomerase catalytic core consisting of the telomerase reverse transcriptase (TERT) and the integral RNA (TR), which catalyzes DNA synthesis. We review the mechanisms by which oxidatively damaged nucleotides, and anti-viral and anti-cancer nucleotide drugs affect the telomerase catalytic cycle. Finally, we offer perspective on how we can leverage telomerase's unique properties, and advancements in understanding of telomerase catalytic mechanism, to selectively manipulate telomerase activity with therapeutics, particularly in cancer treatment.
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23
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Erdem HB, Bahsi T, Ergün MA. Function of telomere in aging and age related diseases. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2021; 85:103641. [PMID: 33774188 DOI: 10.1016/j.etap.2021.103641] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/08/2021] [Accepted: 03/22/2021] [Indexed: 06/12/2023]
Abstract
Telomeres consist of specialized non-coding DNA repeat sequences. They are essential for preserving the integrity of the genome during cancer development, senescence. Mammalian telomeres might have 1-50 kb of telomeric DNA, which becomes 40-200 base pairs shorter after per cell cycle, and becomes 5-8 kilobase shorter during senescence. There are many studies on the correlation of telomere length and aging rate. However, as the differences in the methods used in the studies and the scarcity of prospective studies, factors affecting telomere length are not really well understood. Some of the age related diseases may develop due to telomere dysfunction and telomere shortness. The short telomere structure detected in both peripheral blood leukocytes and cells of the disease-related tissue has the feature of being a predictive marker for many age-related diseases. It is expected that with future research, telomere length analysis is expected to enter clinical practice.
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Affiliation(s)
- Haktan Bağış Erdem
- Department of Medical Genetics, University of Health Sciences, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Yenimahalle, Ankara, Turkey.
| | - Taha Bahsi
- Department of Medical Genetics, University of Health Sciences, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Yenimahalle, Ankara, Turkey.
| | - Mehmet Ali Ergün
- Department of Medical Genetics, Faculty of Medicine, Gazi University, Besevler, Ankara, Turkey.
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Jacczak B, Rubiś B, Totoń E. Potential of Naturally Derived Compounds in Telomerase and Telomere Modulation in Skin Senescence and Aging. Int J Mol Sci 2021; 22:6381. [PMID: 34203694 PMCID: PMC8232155 DOI: 10.3390/ijms22126381] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/26/2021] [Accepted: 06/07/2021] [Indexed: 12/14/2022] Open
Abstract
Proper functioning of cells-their ability to divide, differentiate, and regenerate-is dictated by genomic stability. The main factors contributing to this stability are the telomeric ends that cap chromosomes. Telomere biology and telomerase activity have been of interest to scientists in various medical science fields for years, including the study of both cancer and of senescence and aging. All these processes are accompanied by telomere-length modulation. Maintaining the key levels of telomerase component (hTERT) expression and telomerase activity that provide optimal telomere length as well as some nontelomeric functions represents a promising step in advanced anti-aging strategies, especially in dermocosmetics. Some known naturally derived compounds contribute significantly to telomere and telomerase metabolism. However, before they can be safely used, it is necessary to assess their mechanisms of action and potential side effects. This paper focuses on the metabolic potential of natural compounds to modulate telomerase and telomere biology and thus prevent senescence and skin aging.
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Affiliation(s)
| | | | - Ewa Totoń
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, 49 Przybyszewskiego St., 60-355 Poznań, Poland; (B.J.); (B.R.)
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25
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Piñeiro‐Hermida S, Martínez P, Blasco MA. Short and dysfunctional telomeres protect from allergen-induced airway inflammation. Aging Cell 2021; 20:e13352. [PMID: 33942458 PMCID: PMC8135011 DOI: 10.1111/acel.13352] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 02/22/2021] [Accepted: 03/07/2021] [Indexed: 12/17/2022] Open
Abstract
Asthma is a chronic inflammatory disease affecting 300 million people worldwide. As telomere shortening is a well-established hallmark of aging and that asthma incidence decreases with age, here we aimed to study the role of short telomeres in asthma pathobiology. To this end, wild-type and telomerase-deficient mice with short telomeres (third-generation (G3 Tert-/- mice)) were challenged with intranasal house dust mite (HDM) extract. We also challenged with HDM wild-type mice in which we induced a telomere dysfunction by the administration of 6-thio-2´-deoxyguanosine (6-thio-dG). Following HDM exposure, G3 Tert-/- and 6-thio-dG treated mice exhibited attenuated eosinophil counts and presence of hematopoietic stem cells in the bone marrow, as well as lower levels of IgE and circulating eosinophils. Accordingly, both G3 Tert-/- and 6-thio-dG treated wild-type mice displayed reduced airway hyperresponsiveness (AHR), as indicated by decreased airway remodeling and allergic airway inflammation markers in the lung. Furthermore, G3 Tert-/- and 6-thio-dG treated mice showed lower differentiation of Club cells, attenuating goblet cell hyperplasia. Club cells of G3 Tert-/- and 6-thio-dG treated mice displayed increased DNA damage and senescence and reduced proliferation. Thus, short/dysfunctional telomeres play a protective role in murine asthma by impeding both AHR and mucus secretion after HDM exposure. Therefore, our findings imply that telomeres play a relevant role in allergen-induced airway inflammation.
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Affiliation(s)
- Sergio Piñeiro‐Hermida
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Madrid Spain
| | - Paula Martínez
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Madrid Spain
| | - Maria A. Blasco
- Telomeres and Telomerase Group Molecular Oncology Program Spanish National Cancer Centre (CNIO) Madrid Spain
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26
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Sharma P, Jaiswal RK. SPERMIDINE MAINTAINS TELOMERE LENGTH AND DELAYS AGING. CENTRAL ASIAN JOURNAL OF MEDICAL HYPOTHESES AND ETHICS 2021. [DOI: 10.47316/cajmhe.2021.2.1.08] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Spermidine, a natural polyamine, has been noticed for its anti-aging properties. Supplementation of this drug prolongs lifespan and diminishes the incidence of age-related pathology. In the human population, spermidine levels decrease as aging progresses, and a potential link between diminished endogenous spermidine levels and age-related declination has been studied. At the cellular level, autophagy is the prime mode of action of spermidine known to decline with the progress of aging, similarly contributing to the accretion of impaired macromolecules and organelles through aging. Epidemiological statistics support the concept, suggesting that elevated uptake of polyamine delays aging. Here, we overview the effect of autophagy on cellular processes and age-associated diseases, emphasizing the importance of these events to the hallmarks of aging.
There are numerous factors like shortening telomere, oxidative stress, mitochondrial damage, and impaired intracellular calcium signaling, which are influenced by the aging process. We hypothesize that spermidine supplements in the diet increase the telomere length. The proposed hypothesis also brings to light the differentially regulated genes involved in telomere maintenance and aging after spermidine treatment. Knowing the role of spermidine in telomere maintenance would help us understand the molecular mechanism of spermidine's effect on aging.
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27
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Stone RC, Aviv A, Paus R. Telomere Dynamics and Telomerase in the Biology of Hair Follicles and their Stem Cells as a Model for Aging Research. J Invest Dermatol 2021; 141:1031-1040. [PMID: 33509633 DOI: 10.1016/j.jid.2020.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/28/2020] [Accepted: 12/01/2020] [Indexed: 02/06/2023]
Abstract
In this review, we propose that telomere length dynamics play an important but underinvestigated role in the biology of the hair follicle (HF), a prototypic, cyclically remodeled miniorgan that shows an intriguing aging pattern in humans. Whereas the HF pigmentary unit ages quickly, its epithelial stem cell (ESC) component and regenerative capacity are surprisingly aging resistant. Telomerase-deficient mice with short telomeres display an aging phenotype of hair graying and hair loss that is attributed to impaired HF ESC mobilization. Yet, it remains unclear whether the function of telomerase and telomeres in murine HF biology translate to the human system. Therefore, we propose new directions for future telomere research of the human HF. Such research may guide the development of novel treatments for selected disorders of human hair growth or pigmentation (e.g., chemotherapy-induced alopecia, telogen effluvium, androgenetic alopecia, cicatricial alopecia, graying). It might also increase the understanding of the global role of telomeres in aging-related human disease.
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Affiliation(s)
- Rivka C Stone
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA.
| | - Abraham Aviv
- The Center of Human Development and Aging, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Ralf Paus
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, Florida, USA; Centre for Dermatology Research, University of Manchester, Manchester, United Kingdom; Monasterium Laboratory, Münster, Germany
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Piñeiro-Hermida S, Autilio C, Martínez P, Bosch F, Pérez-Gil J, Blasco MA. Telomerase treatment prevents lung profibrotic pathologies associated with physiological aging. J Cell Biol 2021; 219:152010. [PMID: 32777016 PMCID: PMC7659728 DOI: 10.1083/jcb.202002120] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 02/08/2023] Open
Abstract
Short/dysfunctional telomeres are at the origin of idiopathic pulmonary fibrosis (IPF) in patients mutant for telomere maintenance genes. However, it remains unknown whether physiological aging leads to short telomeres in the lung, thus leading to IPF with aging. Here, we find that physiological aging in wild-type mice leads to telomere shortening and a reduced proliferative potential of alveolar type II cells and club cells, increased cellular senescence and DNA damage, increased fibroblast activation and collagen deposits, and impaired lung biophysics, suggestive of a fibrosis-like pathology. Treatment of both wild-type and telomerase-deficient mice with telomerase gene therapy prevented the onset of lung profibrotic pathologies. These findings suggest that short telomeres associated with physiological aging are at the origin of IPF and that a potential treatment for IPF based on telomerase activation would be of interest not only for patients with telomerase mutations but also for sporadic cases of IPF associated with physiological aging.
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Affiliation(s)
- Sergio Piñeiro-Hermida
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid, Spain
| | - Chiara Autilio
- Department of Biochemistry and Molecular Biology, Research Institute "Hospital 12 de Octubre (imas12)," Complutense University, Madrid, Spain
| | - Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid, Spain
| | - Fátima Bosch
- Center of Animal Biotechnology and Gene Therapy, Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Jesús Pérez-Gil
- Department of Biochemistry and Molecular Biology, Research Institute "Hospital 12 de Octubre (imas12)," Complutense University, Madrid, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre, Madrid, Spain
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Saraswati S, Martínez P, Graña-Castro O, Blasco MA. Short and dysfunctional telomeres sensitize the kidneys to develop fibrosis. ACTA ACUST UNITED AC 2021; 1:269-283. [PMID: 37118410 DOI: 10.1038/s43587-021-00040-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 02/02/2021] [Indexed: 02/08/2023]
Abstract
Accumulation of short telomeres is a hallmark of aging. Mutations in telomerase or telomere-binding proteins lead to telomere shortening or dysfunction and are at the origin of human pathologies known as 'telomere syndromes', which are characterized by loss of the regenerative capacity of tissues and fibrotic pathologies. Here, we generated two mouse models of kidney fibrosis, either by combining telomerase deficiency to induce telomere shortening and a low dose of folic acid, or by conditionally deleting Trf1, a component of the shelterin telomere protective complex, from the kidneys. We find that short telomeres sensitize the kidneys to develop fibrosis in response to folic acid and exacerbate the epithelial-to-mesenchymal transition (EMT) program. Trf1 deletion in kidneys led to fibrosis and EMT activation. Our findings suggest that telomere shortening or dysfunction may contribute to pathological, age-associated renal fibrosis by influencing the EMT program.
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Cai Y, Liu H, Song E, Wang L, Xu J, He Y, Zhang D, Zhang L, Cheng KKY, Jin L, Wu M, Liu S, Qi D, Zhang L, Lopaschuk GD, Wang S, Xu A, Xia Z. Deficiency of telomere-associated repressor activator protein 1 precipitates cardiac aging in mice via p53/PPARα signaling. Theranostics 2021; 11:4710-4727. [PMID: 33754023 PMCID: PMC7978321 DOI: 10.7150/thno.51739] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Accepted: 02/15/2021] [Indexed: 12/13/2022] Open
Abstract
Background: Telomere shortening and dysfunction may cause metabolic disorders, tissue damage and age-dependent pathologies. However, little is known about the association of telomere-associated protein Rap1 with mitochondrial energy metabolism and cardiac aging. Methods: Echocardiography was performed to detect cardiac structure and function in Rap1+/+ and Rap1-/- mice at different ages (3 months, 12 months and 20 months). Telomere length, DNA damage, cardiac senescence and cardiomyocyte size were analyzed using the real-time PCR, Western blotting, senescence associated β-galactosidase assay and wheat germ agglutinin staining, respectively. Western blotting was also used to determine the level of cardiac fatty acid metabolism related key enzymes in mouse and human myocardium. Chromatin immunoprecipitation assay was used to verify the direct link between p53 and PPARα. The p53 inhibitor, Pifithrin-α and PPARα activator WY14643 were utilized to identify the effects of Rap1/p53/PPARα signaling pathway. Results: Telomere was shortened concomitant with extensive DNA damage in aged Rap1-/- mouse hearts, evidenced by reduced T/S ratios and increased nuclear γH2AX. Meanwhile, the aging-associated phenotypes were pronounced as reflected by altered mitochondrial ultrastructure, enhanced senescence, cardiac hypertrophy and dysfunction. Mechanistically, acetylated p53 and nuclear p53 was enhanced in the Rap1-/- mouse hearts, concomitant with reduced PPARα. Importantly, p53 directly binds to the promoter of PPARα in mouse hearts and suppresses the transcription of PPARα. In addition, aged Rap1-/- mice exhibited reduced cardiac fatty acid metabolism. Pifithrin-α alleviated cardiac aging and enhanced fatty acid metabolism in the aged Rap1-/- mice. Activating PPARα with WY14643 in primarily cultured Rap1-/- cardiomyocytes restored maximal oxygen consumption rates. Reduced Rap1 expression and impaired p53/PPARα signaling also presented in aged human myocardium. Conclusion: In summary, Rap1 may link telomere biology to fatty acid metabolism and aging-related cardiac pathologies via modulating the p53/PPARα signaling pathway, which could represent a therapeutic target in preventing/attenuating cardiac aging.
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31
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Principles of the Molecular and Cellular Mechanisms of Aging. J Invest Dermatol 2021; 141:951-960. [PMID: 33518357 DOI: 10.1016/j.jid.2020.11.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 12/13/2022]
Abstract
Aging can be defined as a state of progressive functional decline accompanied by an increase in mortality. Time-dependent accumulation of cellular damage, namely lesions and mutations in the DNA and misfolded proteins, impair organellar and cellular function. Ensuing cell fate alterations lead to the accumulation of dysfunctional cells and hamper homeostatic processes, thus limiting regenerative potential; trigger low-grade inflammation; and alter intercellular and intertissue communication. The accumulation of molecular damage together with modifications in the epigenetic landscape, dysregulation of gene expression, and altered endocrine communication, drive the aging process and establish age as the main risk factor for age-associated diseases and multimorbidity.
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Chakravarti D, LaBella KA, DePinho RA. Telomeres: history, health, and hallmarks of aging. Cell 2021; 184:306-322. [PMID: 33450206 DOI: 10.1016/j.cell.2020.12.028] [Citation(s) in RCA: 236] [Impact Index Per Article: 78.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/14/2020] [Accepted: 12/16/2020] [Indexed: 02/06/2023]
Abstract
The escalating social and economic burden of an aging world population has placed aging research at center stage. The hallmarks of aging comprise diverse molecular mechanisms and cellular systems that are interrelated and act in concert to drive the aging process. Here, through the lens of telomere biology, we examine how telomere dysfunction may amplify or drive molecular biological processes underlying each hallmark of aging and contribute to development of age-related diseases such as neurodegeneration and cancer. The intimate link of telomeres to aging hallmarks informs preventive and therapeutic interventions designed to attenuate aging itself and reduce the incidence of age-associated diseases.
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Affiliation(s)
- Deepavali Chakravarti
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Kyle A LaBella
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ronald A DePinho
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Sanchez-Vazquez R, Guío-Carrión A, Zapatero-Gaviria A, Martínez P, Blasco MA. Shorter telomere lengths in patients with severe COVID-19 disease. Aging (Albany NY) 2021; 13:1-15. [PMID: 33428591 PMCID: PMC7835063 DOI: 10.18632/aging.202463] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 12/22/2020] [Indexed: 12/15/2022]
Abstract
The incidence of severe manifestations of COVID-19 increases with age with older patients showing the highest mortality, suggesting that molecular pathways underlying aging contribute to the severity of COVID-19. One mechanism of aging is the progressive shortening of telomeres, which are protective structures at chromosome ends. Critically short telomeres impair the regenerative capacity of tissues and trigger loss of tissue homeostasis and disease. The SARS-CoV-2 virus infects many different cell types, forcing cell turn-over and regeneration to maintain tissue homeostasis. We hypothesize that presence of short telomeres in older patients limits the tissue response to SARS-CoV-2 infection. We measure telomere length in peripheral blood lymphocytes COVID-19 patients with ages between 29 and 85 years-old. We find that shorter telomeres are associated to increased severity of the disease. Individuals within the lower percentiles of telomere length and higher percentiles of short telomeres have higher risk of developing severe COVID-19 pathologies.
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Affiliation(s)
- Raul Sanchez-Vazquez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
| | - Ana Guío-Carrión
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
| | | | - Paula Martínez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Melchor Fernández Almagro 3, Madrid, Spain
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34
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Spatio-temporal regulation of gene expression defines subpopulations of epidermal stem cells. Biochem Soc Trans 2020; 48:2839-2850. [PMID: 33170265 DOI: 10.1042/bst20200740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 02/06/2023]
Abstract
The search for epidermal stem cells has gained the momentum as they possess unique biological characteristics and a potential in regeneration therapies. Several transcription factors and miRNAs have been identified as epidermal stem cell markers. However, the separation of epidermal stem cells from their progeny remains challenging. The introduction of single-cell transcriptomics pointed to the high degree of heterogeneity in epidermal stem cells imbedded within subpopulations of keratinocytes. Pseudotime inference, RNA velocity, and cellular entropy further enhanced our knowledge of stem cells, allowing for the discovery of the epidermal stem cell plasticity. We explore the main findings that lead to the discovery of the plastic trait within the epidermal stem cells and the implications of cell plasticity in regenerative medicine.
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Flora P, Ezhkova E. Regulatory mechanisms governing epidermal stem cell function during development and homeostasis. Development 2020; 147:147/22/dev194100. [PMID: 33191273 DOI: 10.1242/dev.194100] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cell divisions and cell-fate decisions require stringent regulation for proper tissue development and homeostasis. The mammalian epidermis is a highly organized tissue structure that is sustained by epidermal stem cells (ESCs) that balance self-renewal and cell-fate decisions to establish a protective barrier, while replacing dying cells during homeostasis and in response to injury. Extensive work over past decades has provided insights into the regulatory mechanisms that control ESC specification, self-renewal and maintenance during different stages of the lifetime of an organism. In this Review, we discuss recent findings that have furthered our understanding of key regulatory features that allow ESCs to establish a functional barrier during development and to maintain tissue homeostasis in adults.
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Affiliation(s)
- Pooja Flora
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | - Elena Ezhkova
- Black Family Stem Cell Institute, Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, USA
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Whittemore K, Derevyanko A, Martinez P, Serrano R, Pumarola M, Bosch F, Blasco MA. Telomerase gene therapy ameliorates the effects of neurodegeneration associated to short telomeres in mice. Aging (Albany NY) 2020; 11:2916-2948. [PMID: 31140977 PMCID: PMC6555470 DOI: 10.18632/aging.101982] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/17/2019] [Indexed: 12/26/2022]
Abstract
Neurodegenerative diseases associated with old age such as Alzheimer’s disease present major problems for society, and they currently have no cure. The telomere protective caps at the ends of chromosomes shorten with age, and when they become critically short, they can induce a persistent DNA damage response at chromosome ends, triggering secondary cellular responses such as cell death and cellular senescence. Mice and humans with very short telomeres owing to telomerase deficiencies have an earlier onset of pathologies associated with loss of the regenerative capacity of tissues. However, the effects of short telomeres in very low proliferative tissues such as the brain have not been thoroughly investigated. Here, we describe a mouse model of neurodegeneration owing to presence of short telomeres in the brain as the consequence of telomerase deficiency. Interestingly, we find similar signs of neurodegeneration in very old mice as the consequence of physiological mouse aging. Next, we demonstrate that delivery of telomerase gene therapy to the brain of these mice results in amelioration of some of these neurodegeneration phenotypes. These findings suggest that short telomeres contribute to neurodegeneration diseases with aging and that telomerase activation may have a therapeutic value in these diseases.
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Affiliation(s)
- Kurt Whittemore
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Aksinya Derevyanko
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Paula Martinez
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Rosa Serrano
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
| | - Martí Pumarola
- Unit of Murine and Comparative Pathology (UPMiC), Department of Animal Medicine and Surgery, Veterinary Faculty, Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Barcelona, Spain.,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Universitat Autònoma de Barcelona, 08193 Bellaterra (Cerdanyola del Vallès), Barcelona, Spain
| | - Fàtima Bosch
- Center of Animal Biotechnology and Gene Therapy, Department of Animal Medicine and Surgery, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain.,Center of Animal Biotechnology and Gene Therapy, Department of Biochemistry and Molecular Biology, School of Veterinary Medicine, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain
| | - Maria A Blasco
- Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid 28029, Spain
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De la Torre-Espinosa ZY, Barredo-Pool F, Castaño de la Serna E, Sánchez-Teyer LF. Active telomerase during leaf growth and increase of age in plants from Agave tequilana var. Azul. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:639-647. [PMID: 32255928 PMCID: PMC7113356 DOI: 10.1007/s12298-020-00781-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/28/2020] [Accepted: 02/19/2020] [Indexed: 06/11/2023]
Abstract
In plants, previous studies show that telomerase activity contributes to the maintenance of telomeric length for the proper development of organs and tissues. In this work, we investigated telomerase activity in A. tequilana during several years of cultivation. We found that during growth of the leaf there are two crucial phases: (1) the onset of cell elongation in 3 years and (2) differentiation of vascular bundles in 6 years. This coincides with the ages where the highest telomerase activity is seen. Therefore indicates that telomerase is associated with cellular activities such as; elongation, division, and cell differentiation. Likewise, we detected high activity during the period of vegetative growth, indicating that telomerase also contributes to telomeric maintenance on the leaf in A. tequilana.
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Affiliation(s)
- Zamaria Yoselin De la Torre-Espinosa
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
| | - Felipe Barredo-Pool
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
| | - Enrique Castaño de la Serna
- Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
| | - Lorenzo Felipe Sánchez-Teyer
- Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C. Calle 43 No. 130, Colonia Chuburná de Hidalgo, Mérida, Yucatan Mexico
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Nemirovich-Danchenko NM, Khodanovich MY. Telomerase Gene Editing in the Neural Stem Cells in vivo as a Possible New Approach against Brain Aging. RUSS J GENET+ 2020. [DOI: 10.1134/s1022795420040092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Dolejs J, Homolková H. Why Does Child Mortality Decrease With Age? Modeling the Age-Associated Decrease in Mortality Rate Using WHO Metadata From 14 European Countries. Front Pediatr 2020; 8:527811. [PMID: 33194882 PMCID: PMC7653179 DOI: 10.3389/fped.2020.527811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 09/28/2020] [Indexed: 11/26/2022] Open
Abstract
Background: Mortality rate rapidly decreases with age after birth, and, simultaneously, the spectrum of death causes show remarkable changes with age. This study analyzed age-associated decreases in mortality rate from diseases of all main chapters of the 10th revision of the International Classification of Diseases. Methods: The number of deaths was extracted from the mortality database of the World Health Organization. As zero cases could be ascertained for a specific age category, the Halley method was used to calculate the mortality rates in all possible calendar years and in all countries combined. Results: All causes mortality from the 1st day of life to the age of 10 years can be represented by an inverse proportion model with a single parameter. High coefficients of determination were observed for total mortality in all populations (arithmetic mean = 0.9942 and standard deviation = 0.0039). Slower or no mortality decrease with age was detected in the 1st year of life, while the inverse proportion method was valid for the age range [1, 10) years in most of all main chapters with three exceptions. The decrease was faster for the chapter "Certain conditions originating in the perinatal period" (XVI).The inverse proportion was valid already from the 1st day for the chapter "Congenital malformations, deformations and chromosomal abnormalities" (XVII).The shape of the mortality decrease was very different for the chapter "Neoplasms" (II) and the rates of mortality from neoplasms were age-independent in the age range [1, 10) years in all populations. Conclusion: The theory of congenital individual risks of death is presented and can explain the results. If it is valid, latent congenital impairments may be present among all cases of death that are not related to congenital impairments. All results are based on published data, and the data are presented as a supplement.
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Affiliation(s)
- Josef Dolejs
- Department of Informatics and Quantitative Methods, University of Hradec Králové, Hradec Králové, Czechia
| | - Helena Homolková
- Division of Pediatric Neurosurgery, Department of Pediatric and Trauma Surgery, Thomayer's Teaching Hospital and Third Faculty of Medicine, Charles University in Prague, Prague, Czechia
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Bellei B, Picardo M. Premature cell senescence in human skin: Dual face in chronic acquired pigmentary disorders. Ageing Res Rev 2020; 57:100981. [PMID: 31733332 DOI: 10.1016/j.arr.2019.100981] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 10/16/2019] [Accepted: 11/07/2019] [Indexed: 01/10/2023]
Abstract
Although senescence was originally described as an in vitro acquired cellular characteristic, it was recently recognized that senescence is physiologically and pathologically involved in aging and age-related diseases in vivo. The definition of cellular senescence has expanded to include the growth arrest caused by various cellular stresses, including DNA damage, inadequate mitochondria function, activated oncogene or tumor suppressor genes and oxidative stress. While senescence in normal aging involves various tissues over time and contributes to a decline in tissue function even with healthy aging, disease-induced premature senescence may be restricted to one or a few organs triggering a prolonged and more intense rate of accumulation of senescent cells than in normal aging. Organ-specific high senescence rate could lead to chronic diseases, especially in post-mitotic rich tissue. Recently, two opposite acquired pathological conditions related to skin pigmentation were described to be associated with premature senescence: vitiligo and melasma. In both cases, it was demonstrated that pathological dysfunctions are not restricted to melanocytes, the cell type responsible for melanin production and transport to surrounding keratinocytes. Similar to physiological melanogenesis, dermal and epidermal cells contribute directly and indirectly to deregulate skin pigmentation as a result of complex intercellular communication. Thus, despite senescence usually being reported as a uniform phenotype sharing the expression of characteristic markers, skin senescence involving mainly the dermal compartment and its paracrine function could be associated with the disappearance of melanocytes in vitiligo lesions and with the exacerbated activity of melanocytes in the hyperpigmentation spots of melasma. This suggests that the difference may arise in melanocyte intrinsic differences and/or in highly defined microenvironment peculiarities poorly explored at the current state of the art. A similar dualistic phenotype has been attributed to intratumoral stromal cells as cancer-associated fibroblasts presenting a senescent-like phenotype which influence the behavior of neoplastic cells in either a tumor-promoting or tumor-inhibiting manner. Here, we present a framework dissecting senescent-related molecular alterations shared by vitiligo and melasma patients and we also discuss disease-specific differences representing new challenges for treatment.
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Affiliation(s)
- Barbara Bellei
- Laboratory of Cutaneous Physiopathology and Integrated Center for Metabolomics Research, San Gallicano Dermatological Institute, IRCCS, Rome, Italy.
| | - Mauro Picardo
- Laboratory of Cutaneous Physiopathology and Integrated Center for Metabolomics Research, San Gallicano Dermatological Institute, IRCCS, Rome, Italy
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41
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Peters-Hall JR, Min J, Tedone E, Sho S, Siteni S, Mender I, Shay JW. Proliferation of adult human bronchial epithelial cells without a telomere maintenance mechanism for over 200 population doublings. FASEB J 2020; 34:386-398. [PMID: 31914653 PMCID: PMC6956733 DOI: 10.1096/fj.201902376r] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/17/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022]
Abstract
To date, there is no direct evidence of telomerase activity in adult lung epithelial cells, but typical culture conditions only support cell proliferation for 30-40 population doublings (PD), a point at which telomeres remain relatively long. Here we report that in in vitro low stress culture conditions consisting of a fibroblast feeder layer, rho-associated coiled coil protein kinase inhibitor (ROCKi), and low oxygen (2%), normal human bronchial epithelial basal progenitor cells (HBECs) divide for over 200 PD without engaging a telomere maintenance mechanism (almost four times the "Hayflick limit"). HBECs exhibit critically short telomeres at 200 PD and the population of cells start to undergo replicative senescence. Subcloning these late passage cells to clonal density, to mimic lung injury in vivo, selects for rare subsets of HBECs that activate low levels of telomerase activity to maintain short telomeres. CRISPR/Cas9 knockout of human telomerase reverse transcriptase or treatment with the telomerase-mediated telomere targeting agent 6-thio-2'deoxyguanosine abrogates colony growth in these late passage cultures (>200 PD) but not in early passage cultures (<200 PD). To our knowledge, this is the first study to report such long-term growth of HBECs without a telomere maintenance mechanism. This report also provides direct evidence of telomerase activation in HBECs near senescence when telomeres are critically short. This novel cell culture system provides an experimental model to understand how telomerase is regulated in normal adult tissues.
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Affiliation(s)
- Jennifer R. Peters-Hall
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
| | - Jaewon Min
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
| | - Enzo Tedone
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
| | - Sei Sho
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
| | - Silvia Siteni
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
| | - Ilgen Mender
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
| | - Jerry W. Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, USA 75390-9039
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Mice with hyper-long telomeres show less metabolic aging and longer lifespans. Nat Commun 2019; 10:4723. [PMID: 31624261 PMCID: PMC6797762 DOI: 10.1038/s41467-019-12664-x] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 09/19/2019] [Indexed: 12/16/2022] Open
Abstract
Short telomeres trigger age-related pathologies and shorter lifespans in mice and humans. In the past, we generated mouse embryonic (ES) cells with longer telomeres than normal (hyper-long telomeres) in the absence of genetic manipulations, which contributed to all mouse tissues. To address whether hyper-long telomeres have deleterious effects, we generated mice in which 100% of their cells are derived from hyper-long telomere ES cells. We observe that these mice have longer telomeres and less DNA damage with aging. Hyper-long telomere mice are lean and show low cholesterol and LDL levels, as well as improved glucose and insulin tolerance. Hyper-long telomere mice also have less incidence of cancer and an increased longevity. These findings demonstrate that longer telomeres than normal in a given species are not deleterious but instead, show beneficial effects. Telomere shortening is associated with aging. Here the authors analyze mice with hyperlong telomeres and demonstrate that longer telomeres than normal have beneficial effects such as delayed metabolic aging, increased longevity and less incidence of cancer.
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Abstract
Telomeres, the protective ends of linear chromosomes, shorten throughout an individual's lifetime. Accumulation of critically short telomeres is proposed to be a primary molecular cause of aging and age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as or telomeropathies. The rate of telomere shortening throughout life is determined by endogenous (genetic) and external (nongenetic) factors. Therapeutic strategies based on telomerase activation are being developed to treat and prevent telomere-associated diseases, namely aging-related diseases and telomeropathies. Here, we review the molecular mechanisms underlying telomere driven diseases with particular emphasis on cardiovascular diseases.
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Affiliation(s)
- Paula Martínez
- From the Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
| | - Maria A Blasco
- From the Telomeres and Telomerase Group, Molecular Oncology Program, Spanish National Cancer Centre (CNIO), Madrid, Spain
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44
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Folgueras AR, Freitas-Rodríguez S, Velasco G, López-Otín C. Mouse Models to Disentangle the Hallmarks of Human Aging. Circ Res 2019; 123:905-924. [PMID: 30355076 DOI: 10.1161/circresaha.118.312204] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Model organisms have provided fundamental evidence that aging can be delayed and longevity extended. These findings gave rise to a new era in aging research aimed at elucidating the pathways and networks controlling this complex biological process. The identification of 9 hallmarks of aging has established a framework to evaluate the relative contribution of each hallmark and the interconnections among them. In this review, we revisit these hallmarks with the information obtained exclusively through the generation of genetically modified mouse models that have a significant impact on the aging process. We discuss within each hallmark those interventions that accelerate aging or that have been successful at increasing lifespan, with the final goal of identifying the most promising antiaging avenues based on the current knowledge provided by in vivo models.
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Affiliation(s)
- Alicia R Folgueras
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Spain
| | - Sandra Freitas-Rodríguez
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Spain
| | - Gloria Velasco
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Spain
| | - Carlos López-Otín
- From the Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, Spain
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45
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Liu N, Yin Y, Wang H, Zhou Z, Sheng X, Fu H, Guo R, Wang H, Yang J, Gong P, Ning W, Ju Z, Liu Y, Liu L. Telomere dysfunction impairs epidermal stem cell specification and differentiation by disrupting BMP/pSmad/P63 signaling. PLoS Genet 2019; 15:e1008368. [PMID: 31518356 PMCID: PMC6760834 DOI: 10.1371/journal.pgen.1008368] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 09/25/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
Telomere shortening is associated with aging and age-associated diseases. Additionally, telomere dysfunction resulting from telomerase gene mutation can lead to premature aging, such as apparent skin atrophy and hair loss. However, the molecular signaling linking telomere dysfunction to skin atrophy remains elusive. Here we show that dysfunctional telomere disrupts BMP/pSmad/P63 signaling, impairing epidermal stem cell specification and differentiation of skin and hair follicles. We find that telomere shortening mediated by Terc loss up-regulates Follistatin (Fst), inhibiting pSmad signaling and down-regulating P63 and epidermal keratins in an ESC differentiation model as well as in adult development of telomere-shortened mice. Mechanistically, short telomeres disrupt PRC2/H3K27me3-mediated repression of Fst. Our findings reveal that skin atrophy due to telomere dysfunction is caused by a previously unappreciated link with Fst and BMP signaling that could be explored in the development of therapies.
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Affiliation(s)
- Na Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
- Key Laboratory of Bioactive Materials, Ministry of Education, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China
- School of Medicine, Nankai University, Tianjin, China
| | - Yu Yin
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
- Yunnan Key Laboratory of Primate Biomedical Research; Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, China
| | - Haiying Wang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Zhongcheng Zhou
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Xiaoyan Sheng
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Haifeng Fu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Renpeng Guo
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Hua Wang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Jiao Yang
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Peng Gong
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Wen Ning
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
| | - Zhenyu Ju
- Key Laboratory of Regenerative Medicine of Ministry of Education, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, China
| | - Yifei Liu
- Yale Fertility Center and Department of OB/GYN, Yale University School of Medicine, New Haven, CT, United States of America
- * E-mail: (YL); (LL)
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, China
- Key Laboratory of Bioactive Materials, Ministry of Education, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin, China
- * E-mail: (YL); (LL)
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46
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Enhanced cardiac repair by telomerase reverse transcriptase over-expression in human cardiac mesenchymal stromal cells. Sci Rep 2019; 9:10579. [PMID: 31332256 PMCID: PMC6646304 DOI: 10.1038/s41598-019-47022-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 07/08/2019] [Indexed: 12/11/2022] Open
Abstract
We have previously reported a subpopulation of mesenchymal stromal cells (MSCs) within the platelet-derived growth factor receptor-alpha (PDGFRα)/CD90 co-expressing cardiac interstitial and adventitial cell fraction. Here we further characterise PDGFRα/CD90-expressing cardiac MSCs (PDGFRα + cMSCs) and use human telomerase reverse transcriptase (hTERT) over-expression to increase cMSCs ability to repair the heart after induced myocardial infarction. hTERT over-expression in PDGFRα + cardiac MSCs (hTERT + PDGFRα + cMSCs) modulates cell differentiation, proliferation, survival and angiogenesis related genes. In vivo, transplantation of hTERT + PDGFRα + cMSCs in athymic rats significantly increased left ventricular function, reduced scar size, increased angiogenesis and proliferation of both cardiomyocyte and non-myocyte cell fractions four weeks after myocardial infarction. In contrast, transplantation of mutant hTERT + PDGFRα + cMSCs (which generate catalytically-inactive telomerase) failed to replicate this cardiac functional improvement, indicating a telomerase-dependent mechanism. There was no hTERT + PDGFRα + cMSCs engraftment 14 days after transplantation indicating functional improvement occurred by paracrine mechanisms. Mass spectrometry on hTERT + PDGFRα + cMSCs conditioned media showed increased proteins associated with matrix modulation, angiogenesis, cell proliferation/survival/adhesion and innate immunity function. Our study shows that hTERT can activate pro-regenerative signalling within PDGFRα + cMSCs and enhance cardiac repair after myocardial infarction. An increased understanding of hTERT’s role in mesenchymal stromal cells from various organs will favourably impact clinical regenerative and anti-cancer therapies.
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47
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Yuan X, Xu D. Telomerase Reverse Transcriptase (TERT) in Action: Cross-Talking with Epigenetics. Int J Mol Sci 2019; 20:ijms20133338. [PMID: 31284662 PMCID: PMC6651578 DOI: 10.3390/ijms20133338] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/01/2019] [Accepted: 07/04/2019] [Indexed: 02/07/2023] Open
Abstract
Telomerase, an RNA-dependent DNA polymerase with telomerase reverse transcriptase (TERT) as the catalytic component, is silent due to the tight repression of the TERT gene in most normal human somatic cells, whereas activated only in small subsets of cells, including stem cells, activated lymphocytes, and other highly proliferative cells. In contrast, telomerase activation via TERT induction is widespread in human malignant cells, which is a prerequisite for malignant transformation. It is well established that TERT/telomerase extends telomere length, thereby conferring sustained proliferation capacity to both normal and cancerous cells. The recent evidence has also accumulated that TERT/telomerase may participate in the physiological process and oncogenesis independently of its telomere-lengthening function. For instance, TERT is shown to interact with chromatin remodeling factors and to regulate DNA methylation, through which multiple cellular functions are attained. In the present review article, we summarize the non-canonical functions of TERT with a special emphasis on its cross-talk with epigenetics: How TERT contributes to epigenetic alterations in physiological processes and cancer, and how the aberrant epigenetics in turn facilitate TERT expression and function, eventually promoting cancer either initiation or progression or both. Finally, we briefly discuss clinical implications of the TERT-related methylation.
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Affiliation(s)
- Xiaotian Yuan
- School of Medicine, Shandong University, Jinan 250012, China.
- Department of Medicine, Center for Molecular Medicine (CMM) and Bioclinicum, Karolinska Institute and Karolinska University Hospital Solna, 171 64 Solna, Sweden.
| | - Dawei Xu
- Department of Medicine, Center for Molecular Medicine (CMM) and Bioclinicum, Karolinska Institute and Karolinska University Hospital Solna, 171 64 Solna, Sweden.
- Shandong University-Karolinska Institute Collaborative Laboratory for Cancer and Stem Cell Research, Jinan 250033, China.
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48
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Wild-type and SAMP8 mice show age-dependent changes in distinct stem cell compartments of the interfollicular epidermis. PLoS One 2019; 14:e0215908. [PMID: 31091266 PMCID: PMC6519801 DOI: 10.1371/journal.pone.0215908] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 04/10/2019] [Indexed: 11/19/2022] Open
Abstract
Delayed wound healing and reduced barrier function with an increased risk of cancer are characteristics of aged skin and one possible mechanism is misregulation or dysfunction of epidermal stem cells during aging. Recent studies have identified heterogeneous stem cell populations within the mouse interfollicular epidermis that are defined by territorial distribution and cell division frequency; however, it is unknown whether the individual stem cell populations undergo distinct aging processes. Here we provide comprehensive characterization of age-related changes in the mouse epidermis within the specific territories of slow-cycling and fast-dividing stem cells using old wild-type, senescence-accelerated mouse prone 1 (SAMP1) and SAMP8 mice. During aging, the epidermis exhibits structural changes such as irregular micro-undulations and overall thinning of the tissue. We also find that, in the old epidermis, proliferation is preferentially decreased in the region where fast-dividing stem cells reside whereas the lineage differentiation marker appears to be more affected in the slow-cycling stem cell region. Furthermore, SAMP8, but not SAMP1, exhibits precocious aging similar to that of aged wild-type mice, suggesting a potential use of this model for aging study of the epidermis and its stem cells. Taken together, our study reveals distinct aging processes governing the two epidermal stem cell populations and suggests a potential mechanism in differential responses of compartmentalized stem cells and their niches to aging.
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49
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Kotla S, Vu HT, Ko KA, Wang Y, Imanishi M, Heo KS, Fujii Y, Thomas TN, Gi YJ, Mazhar H, Paez-Mayorga J, Shin JH, Tao Y, Giancursio CJ, Medina JL, Taunton J, Lusis AJ, Cooke JP, Fujiwara K, Le NT, Abe JI. Endothelial senescence is induced by phosphorylation and nuclear export of telomeric repeat binding factor 2-interacting protein. JCI Insight 2019; 4:124867. [PMID: 31045573 PMCID: PMC6538340 DOI: 10.1172/jci.insight.124867] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/19/2019] [Indexed: 01/03/2023] Open
Abstract
The interplay among signaling events for endothelial cell (EC) senescence, apoptosis, and activation and how these pathological conditions promote atherosclerosis in the area exposed to disturbed flow (d-flow) in concert remain unclear. The aim of this study was to determine whether telomeric repeat-binding factor 2-interacting protein (TERF2IP), a member of the shelterin complex at the telomere, can regulate EC senescence, apoptosis, and activation simultaneously, and if so, by what molecular mechanisms. We found that d-flow induced p90RSK and TERF2IP interaction in a p90RSK kinase activity-dependent manner. An in vitro kinase assay revealed that p90RSK directly phosphorylated TERF2IP at the serine 205 (S205) residue, and d-flow increased TERF2IP S205 phosphorylation as well as EC senescence, apoptosis, and activation by activating p90RSK. TERF2IP phosphorylation was crucial for nuclear export of the TERF2IP-TRF2 complex, which led to EC activation by cytosolic TERF2IP-mediated NF-κB activation and also to senescence and apoptosis of ECs by depleting TRF2 from the nucleus. Lastly, using EC-specific TERF2IP-knockout (TERF2IP-KO) mice, we found that the depletion of TERF2IP inhibited d-flow-induced EC senescence, apoptosis, and activation, as well as atherosclerotic plaque formation. These findings demonstrate that TERF2IP is an important molecular switch that simultaneously accelerates EC senescence, apoptosis, and activation by S205 phosphorylation.
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Affiliation(s)
- Sivareddy Kotla
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Hang Thi Vu
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Kyung Ae Ko
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yin Wang
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Masaki Imanishi
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Kyung-Sun Heo
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yuka Fujii
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tamlyn N. Thomas
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Young Jin Gi
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Hira Mazhar
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jesus Paez-Mayorga
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, Texas, USA
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Monterrey, Nuevo Leon, Mexico
| | - Ji-Hyun Shin
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yunting Tao
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, Texas, USA
| | - Carolyn J. Giancursio
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, Texas, USA
| | - Jan L.M. Medina
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, California, USA
| | - Aldos J. Lusis
- Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, California, USA
| | - John P. Cooke
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, Texas, USA
| | - Keigi Fujiwara
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Nhat-Tu Le
- Center for Cardiovascular Regeneration, Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, Texas, USA
| | - Jun-ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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50
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Liu T, Gonzalez De Los Santos F, Zhao Y, Wu Z, Rinke AE, Kim KK, Phan SH. Telomerase reverse transcriptase ameliorates lung fibrosis by protecting alveolar epithelial cells against senescence. J Biol Chem 2019; 294:8861-8871. [PMID: 31000627 DOI: 10.1074/jbc.ra118.006615] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 04/11/2019] [Indexed: 11/06/2022] Open
Abstract
Mutations in the genes encoding telomerase reverse transcriptase (TERT) and telomerase's RNA components as well as shortened telomeres are risk factors for idiopathic pulmonary fibrosis, where repetitive injury to the alveolar epithelium is considered a key factor in pathogenesis. Given the importance of TERT in stem cells, we hypothesized that TERT plays an important role in epithelial repair and that its deficiency results in exacerbation of fibrosis by impairing this repair/regenerative process. To evaluate the role of TERT in epithelial cells, we generated type II alveolar epithelial cell (AECII)-specific TERT conditional knockout (SPC-Tert cKO) mice by crossing floxed Tert mice with inducible SPC-driven Cre mice. SPC-Tert cKO mice did not develop pulmonary fibrosis spontaneously up to 9 months of TERT deficiency. However, upon bleomycin treatment, they exhibited enhanced lung injury, inflammation, and fibrosis compared with control mice, accompanied by increased pro-fibrogenic cytokine expression but without a significant effect on AECII telomere length. Moreover, selective TERT deficiency in AECII diminished their proliferation and induced cellular senescence. These findings suggest that AECII-specific TERT deficiency enhances pulmonary fibrosis by heightening susceptibility to bleomycin-induced epithelial injury and diminishing epithelial regenerative capacity because of increased cellular senescence. We confirmed evidence for increased AECII senescence in idiopathic pulmonary fibrosis lungs, suggesting potential clinical relevance of the findings from our animal model. Our results suggest that TERT has a protective role in AECII, unlike its pro-fibrotic activity, observed previously in fibroblasts, indicating that TERT's role in pulmonary fibrosis is cell type-specific.
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Affiliation(s)
| | | | | | - Zhe Wu
- From the Departments of Pathology and
| | | | - Kevin K Kim
- Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109
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