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Ortega A, Chernicki B, Ou G, Parmar MS. From Lab Bench to Hope: Emerging Gene Therapies in Clinical Trials for Alzheimer's Disease. Mol Neurobiol 2024:10.1007/s12035-024-04285-3. [PMID: 38958888 DOI: 10.1007/s12035-024-04285-3] [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: 02/29/2024] [Accepted: 06/05/2024] [Indexed: 07/04/2024]
Abstract
Alzheimer's disease is a progressive neurodegenerative disorder that affects memory and cognitive abilities, affecting millions of people around the world. Current treatments focus on the management of symptoms, as no effective therapy has been approved to modify the underlying disease process. Gene therapy is a promising approach that can offer disease-modifying treatment for AD, targeting various aspects of the pathophysiology of the disease. This review presents a comprehensive overview of the current state of gene therapy research for AD, with a specific focus on clinical trials and preclinical studies that have used nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), apolipoprotein E2 (APOE2), and human telomerase reverse transcriptase (hTERT) as therapeutic gene therapy approaches. These gene targets have shown potential to alleviate the neuropathology of AD in animal studies and have demonstrated feasibility and safety in non-human primates. Despite the failure of the NGF gene therapy approach in clinical trials, we have reviewed and highlighted the reported findings and evaluations from the trials. Furthermore, the review included the conclusions of postmortem brain tissue analysis of AD patients who received NGF gene therapy. The goal is to learn from the failed trials and improve the approach in the future. Although gene therapy shows promise, it faces several challenges and limitations, including optimizing gene delivery methods, enhancing safety and efficacy profiles, and determining long-term results. This review contributes to the growing body of literature on innovative treatments for AD and highlights the need for more research and development to advance gene therapy as a viable treatment option for AD.
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Affiliation(s)
- Angelica Ortega
- Dr. Kiran C. Patel College of Osteopathic Medicine, Nova Southeastern University, Clearwater, FL, USA
| | - Brendan Chernicki
- Dr. Kiran C. Patel College of Osteopathic Medicine, Nova Southeastern University, Clearwater, FL, USA
| | - Grace Ou
- College of Arts and Sciences, Cornell University, Ithaca, NY, USA
| | - Mayur S Parmar
- Dr. Kiran C. Patel College of Osteopathic Medicine, Nova Southeastern University, Clearwater, FL, USA.
- Department of Foundational Sciences, Dr. Kiran C. Patel College of Osteopathic Medicine, Nova Southeastern University, Clearwater, FL, USA.
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Wang X, Deng H, Lin J, Zhang K, Ni J, Li L, Fan G. Distinct roles of telomerase activity in age-related chronic diseases: An update literature review. Biomed Pharmacother 2023; 167:115553. [PMID: 37738798 DOI: 10.1016/j.biopha.2023.115553] [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: 07/22/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/24/2023] Open
Abstract
Although telomerase has low activity in somatic quiescent cells, it plays an significant roles in regenerative cells such as endothelial cells, hepatocytes, epithelial cells, and hemocytes. Telomerase activity and telomere length are critical factors in age-related chronic diseases as they are closely related to cell senescence. However, whether telomerase activity plays a key role in disease progression or whether the role of telomerase is unified among different diseases are unresolved. Considering that aging is the most important risk factor for neurodegenerative and metabolic diseases, this article will analyze the evidence, mechanism, and therapeutic potential of telomerase activity in several chronic disease, including type 2 diabetes, neurodegenerative diseases, atherosclerosis, heart failure and non-alcoholic fatty liver disease, in order to provide clues for the use of telomerase activity to target the treatment of age-related chronic diseases.
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Affiliation(s)
- Xiaodan Wang
- Medical Experiment Center, Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300381 Tianjin, China
| | - Hao Deng
- Medical Experiment Center, Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300381 Tianjin, China
| | - Jingyi Lin
- Medical Experiment Center, Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300381 Tianjin, China
| | - Kai Zhang
- Medical Experiment Center, Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300381 Tianjin, China
| | - Jingyu Ni
- Medical Experiment Center, Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300381 Tianjin, China
| | - Lan Li
- State Key Laboratory of Modern Chinese Medicine, Key Laboratory of Pharmacology of Traditional Chinese Medical Formulae for the Ministry of Education, Tianjin University of Traditional Chinese Medicine, Tianjin 301617, China
| | - Guanwei Fan
- Medical Experiment Center, Tianjin Key Laboratory of Translational Research of TCM Prescription and Syndrome, National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, 300381 Tianjin, China.
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Yu X, Liu MM, Zheng CY, Liu YT, Wang Z, Wang ZY. Telomerase reverse transcriptase and neurodegenerative diseases. Front Immunol 2023; 14:1165632. [PMID: 37063844 PMCID: PMC10091515 DOI: 10.3389/fimmu.2023.1165632] [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: 02/14/2023] [Accepted: 03/15/2023] [Indexed: 03/31/2023] Open
Abstract
Neurodegenerative diseases (NDs) are chronic conditions that result in progressive damage to the nervous system, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and Amyotrophic lateral sclerosis (ALS). Age is a major risk factor for NDs. Telomere shortening is a biological marker of cellular aging, and telomerase reverse transcriptase (TERT) has been shown to slow down this process by maintaining telomere length. The blood-brain barrier (BBB) makes the brain a unique immune organ, and while the number of T cells present in the central nervous system is limited, they play an important role in NDs. Research suggests that NDs can be influenced by modulating peripheral T cell immune responses, and that TERT may play a significant role in T cell senescence and NDs. This review focuses on the current state of research on TERT in NDs and explores the potential connections between TERT, T cells, and NDs. Further studies on aging and telomeres may provide valuable insights for developing therapeutic strategies for age-related diseases.
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Marinaccio J, Micheli E, Udroiu I, Di Nottia M, Carrozzo R, Baranzini N, Grimaldi A, Leone S, Moreno S, Muzzi M, Sgura A. TERT Extra-Telomeric Roles: Antioxidant Activity and Mitochondrial Protection. Int J Mol Sci 2023; 24:ijms24054450. [PMID: 36901881 PMCID: PMC10002448 DOI: 10.3390/ijms24054450] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/18/2023] [Accepted: 02/20/2023] [Indexed: 03/05/2023] Open
Abstract
Telomerase reverse transcriptase (TERT) is the catalytic subunit of telomerase holoenzyme, which adds telomeric DNA repeats on chromosome ends to counteract telomere shortening. In addition, there is evidence of TERT non-canonical functions, among which is an antioxidant role. In order to better investigate this role, we tested the response to X-rays and H2O2 treatment in hTERT-overexpressing human fibroblasts (HF-TERT). We observed in HF-TERT a reduced induction of reactive oxygen species and an increased expression of the proteins involved in the antioxidant defense. Therefore, we also tested a possible role of TERT inside mitochondria. We confirmed TERT mitochondrial localization, which increases after oxidative stress (OS) induced by H2O2 treatment. We next evaluated some mitochondrial markers. The basal mitochondria quantity appeared reduced in HF-TERT compared to normal fibroblasts and an additional reduction was observed after OS; nevertheless, the mitochondrial membrane potential and morphology were better conserved in HF-TERT. Our results suggest a protective function of TERT against OS, also preserving mitochondrial functionality.
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Affiliation(s)
| | - Emanuela Micheli
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
- Correspondence:
| | - Ion Udroiu
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
| | - Michela Di Nottia
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children’s Hospital IRCCS, 00146 Rome, Italy
| | - Rosalba Carrozzo
- Unit of Muscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children’s Hospital IRCCS, 00146 Rome, Italy
| | - Nicolò Baranzini
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Annalisa Grimaldi
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
| | - Stefano Leone
- Department of Anatomical, Histological, Forensic Medicine and Orthopedics Sciences, Sapienza University of Rome, 00161 Rome, Italy
| | - Sandra Moreno
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
- IRCCS Santa Lucia Foundation, 00179 Rome, Italy
| | - Maurizio Muzzi
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
- IRCCS Santa Lucia Foundation, 00179 Rome, Italy
| | - Antonella Sgura
- Department of Science, University “ROMA TRE”, 00146 Rome, Italy
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One-day thermal regime extends the lifespan in Caenorhabditis elegans. Comput Struct Biotechnol J 2022; 21:495-505. [PMID: 36618984 PMCID: PMC9813578 DOI: 10.1016/j.csbj.2022.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 12/11/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Environmental factors, including temperature, can modulate an animal's lifespan. However, their underlying mechanisms remain largely undefined. We observed a profound effect of temperature on the aging of Caenorhabditis elegans (C. elegans) by performing proteomic analysis at different time points (young adult, middle age, and old age) and temperature conditions (20 °C and 25 °C). Importantly, although at the higher temperature, animals had short life spans, the shift from 20 °C to 25 °C for one day during early adulthood was beneficial for protein homeostasis since; it decreased protein synthesis and increased degradation. Consistent with our findings, animals who lived longer in the 25 °C shift were also more resistant to high temperatures along with oxidative and UV stresses. Furthermore, the lifespan extension by the 25 °C shift was mediated by three important transcription factors, namely FOXO/DAF-16, HSF-1, and HIF-1. We revealed an unexpected and complicated mechanism underlying the effects of temperature on aging, which could potentially aid in developing strategies to treat age-related diseases. Our data are available in ProteomeXchange with the identifier PXD024916.
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Meessen S, Najjar G, Azoitei A, Iben S, Bolenz C, Günes C. A Comparative Assessment of Replication Stress Markers in the Context of Telomerase. Cancers (Basel) 2022; 14:cancers14092205. [PMID: 35565334 PMCID: PMC9103842 DOI: 10.3390/cancers14092205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 04/26/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Genetic alterations such as oncogenic- or aneuploidy-inducing mutations can induce replication stress as a tumor protection mechansim. Previous data indicated that telomerase may ameliorate the cellular responses that induce replication stress. However, the mechanisms how this may occur are still unclear. In order to address this question, the accurate evaluation of replication stress in the presence and absence of telomerase is crucial. Therefore, we used telomerase negative normal human fibroblasts, as well as their telomerase positive counterparts to compare the suitability of three protein markers (pRPA2, γ-H2AX and 53BP1), which were previously reported to accumulate in response to harmful conditions leading to replication stress in cells. In summary, we find that pRPA2 is the most consistent and reliable marker for the detection of replication stress. Further, we demonstrated that the inhibition of the DNA-damage activated ATM and ATR kinases by specific small compounds impaired the accumulation of pRPA2 foci in the absence of telomerase. These data suggest that telomerase rescues the cells from replication stress upon supression of DNA damage induction by modulating the ATM and ATR signaling pathways, and may therefore support tumor formation of genetically unstable cells. Abstract Aberrant replication stress (RS) is a source of genome instability and has serious implications for cell survival and tumourigenesis. Therefore, the detection of RS and the identification of the underlying molecular mechanisms are crucial for the understanding of tumourigenesis. Currently, three protein markers—p33-phosphorylated replication protein A2 (pRPA2), γ-phosphorylated H2AX (γ-H2AX), and Tumor Protein P53 Binding Protein 1 (53BP1)—are frequently used to detect RS. However, to our knowledge, there is no report that compares their suitability for the detection of different sources of RS. Therefore, in this study, we evaluate the suitability of pRPA2, γ-H2AX, and 53BP1 for the detection of RS caused by different sources of RS. In addition, we examine their suitability as markers of the telomerase-mediated alleviation of RS. For these purposes, we use here telomerase-negative human fibroblasts (BJ) and their telomerase-immortalized counterparts (BJ-hTERT). Replication stress was induced by the ectopic expression of the oncogenic RAS mutant RASG12V (OI-RS), by the knockdown of ploidy-control genes ORP3 or MAD2 (AI-RS), and by treatment with hydrogen peroxide (ROS-induced RS). The level of RS was determined by immunofluorescence staining for pRPA2, γ-H2AX, and 53BP1. Evaluation of the staining results revealed that pRPA2- and γ-H2AX provide a significant and reliable assessment of OI-RS and AI-RS compared to 53BP1. On the other hand, 53BP1 and pRPA2 proved to be superior to γ-H2AX for the evaluation of ROS-induced RS. Moreover, the data showed that among the tested markers, pRPA2 is best suited to evaluate the telomerase-mediated suppression of all three types of RS. In summary, the data indicate that the choice of marker is important for the evaluation of RS activated through different conditions.
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Affiliation(s)
- Sabine Meessen
- Department of Urology, Ulm University Hospital, 89081 Ulm, Germany; (S.M.); (G.N.); (A.A.); (C.B.)
| | - Gregoire Najjar
- Department of Urology, Ulm University Hospital, 89081 Ulm, Germany; (S.M.); (G.N.); (A.A.); (C.B.)
| | - Anca Azoitei
- Department of Urology, Ulm University Hospital, 89081 Ulm, Germany; (S.M.); (G.N.); (A.A.); (C.B.)
| | - Sebastian Iben
- Department of Dermatology, Ulm University Hospital, 89081 Ulm, Germany;
| | - Christian Bolenz
- Department of Urology, Ulm University Hospital, 89081 Ulm, Germany; (S.M.); (G.N.); (A.A.); (C.B.)
| | - Cagatay Günes
- Department of Urology, Ulm University Hospital, 89081 Ulm, Germany; (S.M.); (G.N.); (A.A.); (C.B.)
- Correspondence: ; Tel.: +49-(0)731-500-58019; Fax: +49-(0)731-500-58093
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Rossiello F, Jurk D, Passos JF, d'Adda di Fagagna F. Telomere dysfunction in ageing and age-related diseases. Nat Cell Biol 2022; 24:135-147. [PMID: 35165420 PMCID: PMC8985209 DOI: 10.1038/s41556-022-00842-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 01/06/2022] [Indexed: 12/11/2022]
Abstract
Ageing organisms accumulate senescent cells that are thought to contribute to body dysfunction. Telomere shortening and damage are recognized causes of cellular senescence and ageing. Several human conditions associated with normal ageing are precipitated by accelerated telomere dysfunction. Here, we systematize a large body of evidence and propose a coherent perspective to recognize the broad contribution of telomeric dysfunction to human pathologies.
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Affiliation(s)
- Francesca Rossiello
- IFOM Foundation-FIRC Institute of Molecular Oncology Foundation, Milan, Italy
| | - Diana Jurk
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA
| | - João F Passos
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA.
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA.
| | - Fabrizio d'Adda di Fagagna
- IFOM Foundation-FIRC Institute of Molecular Oncology Foundation, Milan, Italy.
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, Italy.
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Fu Y, Bu G, Kanekiyo T, Zhao J. Counteracting Alzheimer's disease via somatic TERT activation. NATURE AGING 2021; 1:1081-1082. [PMID: 37117526 DOI: 10.1038/s43587-021-00145-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Affiliation(s)
- Yuan Fu
- Department of Neurology, The Fourth Hospital of Harbin Medical University, Harbin, China
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Neuroregeneration Laboratory, Center for Regenerative Medicine, Mayo Clinic, Jacksonville, FL, USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Neuroregeneration Laboratory, Center for Regenerative Medicine, Mayo Clinic, Jacksonville, FL, USA
| | - Jing Zhao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
- Neuroregeneration Laboratory, Center for Regenerative Medicine, Mayo Clinic, Jacksonville, FL, USA.
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Shim HS, Horner JW, Wu CJ, Li J, Lan ZD, Jiang S, Xu X, Hsu WH, Zal T, Flores II, Deng P, Lin YT, Tsai LH, Wang YA, DePinho RA. Telomerase Reverse Transcriptase Preserves Neuron Survival and Cognition in Alzheimer's Disease Models. NATURE AGING 2021; 1:1162-1174. [PMID: 35036927 PMCID: PMC8759755 DOI: 10.1038/s43587-021-00146-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 10/29/2021] [Indexed: 12/19/2022]
Abstract
Amyloid-induced neurodegeneration plays a central role in Alzheimer's disease (AD) pathogenesis. Here, we show that telomerase reverse transcriptase (TERT) haploinsufficiency decreases BDNF and increases amyloid-β (Aβ) precursor in murine brain. Moreover, prior to disease onset, the TERT locus sustains accumulation of repressive epigenetic marks in murine and human AD neurons, implicating TERT repression in amyloid-induced neurodegeneration. To test the impact of sustained TERT expression on AD pathobiology, AD mouse models were engineered to maintain physiological levels of TERT in adult neurons, resulting in reduced Aβ accumulation, improved spine morphology, and preserved cognitive function. Mechanistically, integrated profiling revealed that TERT interacts with β-catenin and RNA polymerase II at gene promoters and upregulates gene networks governing synaptic signaling and learning processes. These TERT-directed transcriptional activities do not require its catalytic activity nor telomerase RNA. These findings provide genetic proof-of-concept for somatic TERT gene activation therapy in attenuating AD progression including cognitive decline.
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Affiliation(s)
- Hong Seok Shim
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - James W. Horner
- Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Chang-Jiun Wu
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Jiexi Li
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Zheng D. Lan
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Shan Jiang
- Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Xueping Xu
- Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Wen-Hao Hsu
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Tomasz Zal
- Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Ivonne I. Flores
- Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Pingna Deng
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Yuan-Ta Lin
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Li-Huei Tsai
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Y. Alan Wang
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - Ronald A. DePinho
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
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Mohamed Asik R, Suganthy N, Aarifa MA, Kumar A, Szigeti K, Mathe D, Gulyás B, Archunan G, Padmanabhan P. Alzheimer's Disease: A Molecular View of β-Amyloid Induced Morbific Events. Biomedicines 2021; 9:biomedicines9091126. [PMID: 34572312 PMCID: PMC8468668 DOI: 10.3390/biomedicines9091126] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/22/2021] [Accepted: 08/27/2021] [Indexed: 12/26/2022] Open
Abstract
Amyloid-β (Aβ) is a dynamic peptide of Alzheimer’s disease (AD) which accelerates the disease progression. At the cell membrane and cell compartments, the amyloid precursor protein (APP) undergoes amyloidogenic cleavage by β- and γ-secretases and engenders the Aβ. In addition, externally produced Aβ gets inside the cells by receptors mediated internalization. An elevated amount of Aβ yields spontaneous aggregation which causes organelles impairment. Aβ stimulates the hyperphosphorylation of tau protein via acceleration by several kinases. Aβ travels to the mitochondria and interacts with its functional complexes, which impairs the mitochondrial function leading to the activation of apoptotic signaling cascade. Aβ disrupts the Ca2+ and protein homeostasis of the endoplasmic reticulum (ER) and Golgi complex (GC) that promotes the organelle stress and inhibits its stress recovery machinery such as unfolded protein response (UPR) and ER-associated degradation (ERAD). At lysosome, Aβ precedes autophagy dysfunction upon interacting with autophagy molecules. Interestingly, Aβ act as a transcription regulator as well as inhibits telomerase activity. Both Aβ and p-tau interaction with neuronal and glial receptors elevate the inflammatory molecules and persuade inflammation. Here, we have expounded the Aβ mediated events in the cells and its cosmopolitan role on neurodegeneration, and the current clinical status of anti-amyloid therapy.
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Affiliation(s)
- Rajmohamed Mohamed Asik
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; (R.M.A.); (B.G.)
- Cognitive Neuroimaging Centre, 59 Nanyang Drive, Nanyang Technological University, Singapore 636921, Singapore
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
| | - Natarajan Suganthy
- Department of Nanoscience and Technology, Alagappa University, Karaikudi 630003, Tamil Nadu, India;
| | - Mohamed Asik Aarifa
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
| | - Arvind Kumar
- Centre for Cellular and Molecular Biology, Hyderabad 500007, Telangana, India;
| | - Krisztián Szigeti
- Department of Biophysics and Radiation Biology, Semmelweis University, 1094 Budapest, Hungary; (K.S.); (D.M.)
- CROmed Translational Research Centers, 1094 Budapest, Hungary
| | - Domokos Mathe
- Department of Biophysics and Radiation Biology, Semmelweis University, 1094 Budapest, Hungary; (K.S.); (D.M.)
- CROmed Translational Research Centers, 1094 Budapest, Hungary
- In Vivo Imaging Advanced Core Facility, Hungarian Center of Excellence for Molecular Medicine (HCEMM), 1094 Budapest, Hungary
| | - Balázs Gulyás
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; (R.M.A.); (B.G.)
- Cognitive Neuroimaging Centre, 59 Nanyang Drive, Nanyang Technological University, Singapore 636921, Singapore
- Department of Clinical Neuroscience, Karolinska Institute, 17176 Stockholm, Sweden
| | - Govindaraju Archunan
- Department of Animal Science, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
- Marudupandiyar College, Thanjavur 613403, Tamil Nadu, India
- Correspondence: (G.A.); (P.P.)
| | - Parasuraman Padmanabhan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore; (R.M.A.); (B.G.)
- Cognitive Neuroimaging Centre, 59 Nanyang Drive, Nanyang Technological University, Singapore 636921, Singapore
- Correspondence: (G.A.); (P.P.)
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Cuttler K, Bignoux MJ, Otgaar TC, Chigumba S, Ferreira E, Weiss SFT. LRP::FLAG Reduces Phosphorylated Tau Levels in Alzheimer's Disease Cell Culture Models. J Alzheimers Dis 2021; 76:753-768. [PMID: 32568204 DOI: 10.3233/jad-200244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) plaque and neurofibrillary tangle formation, respectively. Neurofibrillary tangles form as a result of the intracellular accumulation of hyperphosphorylated tau. Telomerase activity and levels of the human reverse transcriptase (hTERT) subunit of telomerase are significantly decreased in AD. Recently, it has been demonstrated that the 37 kDa/67 kDa laminin receptor (LRP/LR) interacts with telomerase and is implicated in Aβ pathology. Since both LRP/LR and telomerase are known to play a role in the Aβ facet of AD, we hypothesized that they might also play a role in tauopathy. OBJECTIVE This study aimed to determine if LRP/LR has a relationship with tau and whether overexpression of LRP::FLAG has an effect on tauopathy-related proteins. METHODS We employed confocal microscopy and FRET to determine whether LRP/LR and tau co-localize and interact. LRP::FLAG overexpression in HEK-293 and SH-SY5Y cells as well as analysis of tauopathy-related proteins was assessed by western blotting. RESULTS We demonstrate that LRP/LR co-localizes with tau in the perinuclear cell compartment and confirmed a direct interaction between LRP/LR and tau in HEK-293 cells. Overexpression of LRP::FLAG in HEK-293 and SH-SY5Y cells decreased total and phosphorylated tau levels with a concomitant decrease in PrPc levels, a tauopathy-related protein. LRP::FLAG overexpression also resulted in increased hTERT levels. CONCLUSION This data suggest that LRP/LR extends its role in AD through a direct interaction with tau, and recommend LRP::FLAG as a possible alternative AD therapeutic via decreasing phosphorylated tau levels.
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Affiliation(s)
- Katelyn Cuttler
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa.,Present Address: Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, Republic of South Africa
| | - Monique J Bignoux
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Tyrone C Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Stephanie Chigumba
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
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Telomerase in Brain: The New Kid on the Block and Its Role in Neurodegenerative Diseases. Biomedicines 2021; 9:biomedicines9050490. [PMID: 33946850 PMCID: PMC8145691 DOI: 10.3390/biomedicines9050490] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/20/2021] [Accepted: 04/25/2021] [Indexed: 01/14/2023] Open
Abstract
Telomerase is an enzyme that in its canonical function extends and maintains telomeres, the ends of chromosomes. This reverse transcriptase function is mainly important for dividing cells that shorten their telomeres continuously. However, there are a number of telomere-independent functions known for the telomerase protein TERT (Telomerase Reverse Transcriptase). This includes the shuttling of the TERT protein from the nucleus to mitochondria where it decreases oxidative stress, apoptosis sensitivity and DNA damage. Recently, evidence has accumulated on a protective role of TERT in brain and postmitotic neurons. This function might be able to ameliorate the effects of toxic proteins such as amyloid-β, pathological tau and α-synuclein involved in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). However, the protective mechanisms of TERT are not clear yet. Recently, an activation of autophagy as an important protein degradation process for toxic neuronal proteins by TERT has been described. This review summarises the current knowledge about the non-canonical role of the telomerase protein TERT in brain and shows its potential benefit for the amelioration of brain ageing and neurodegenerative diseases such as AD and PD. This might form the basis for the development of novel strategies and therapies against those diseases.
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13
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Rajendran K, Chellappan DR, Sankaranarayanan S, Ramakrishnan V, Krishnan UM. Investigations on a polyherbal formulation for treatment of cognitive impairment in a cholinergic dysfunctional rodent model. Neurochem Int 2020; 141:104890. [DOI: 10.1016/j.neuint.2020.104890] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 02/07/2023]
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14
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Increased telomerase improves motor function and alpha-synuclein pathology in a transgenic mouse model of Parkinson's disease associated with enhanced autophagy. Prog Neurobiol 2020; 199:101953. [PMID: 33188884 PMCID: PMC7938226 DOI: 10.1016/j.pneurobio.2020.101953] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 10/21/2020] [Accepted: 11/08/2020] [Indexed: 02/07/2023]
Abstract
Telomerase activators (TA) increase Tert expression in brains of a PD mouse model. Activator treatment improves PD motor symptoms: gait and balance. Activators reduce different forms of alpha-synuclein in brains of transgenic mice. Decreased autophagy markers LC3 and p62 suggest a better protein degradation. Our preclinical data suggest a use of TA to ameliorate PD-like symptoms.
Protective effects of the telomerase protein TERT have been shown in neurons and brain. We previously demonstrated that TERT protein can accumulate in mitochondria of Alzheimer’s disease (AD) brains and protect from pathological tau in primary mouse neurons. This prompted us to employ telomerase activators in order to boost telomerase expression in a mouse model of Parkinson’s disease (PD) overexpressing human wild type α-synuclein. Our aim was to test whether increased Tert expression levels were able to ameliorate PD symptoms and to activate protein degradation. We found increased Tert expression in brain for both activators which correlated with a substantial improvement of motor functions such as gait and motor coordination while telomere length in the analysed region was not changed. Interestingly, only one activator (TA-65) resulted in a decrease of reactive oxygen species from brain mitochondria. Importantly, we demonstrate that total, phosphorylated and aggregated α-synuclein were significantly decreased in the hippocampus and neocortex of activator-treated mice corresponding to enhanced markers of autophagy suggesting an improved degradation of toxic alpha-synuclein. We conclude that increased Tert expression caused by telomerase activators is associated with decreased α-synuclein protein levels either by activating autophagy or by preventing or delaying impairment of degradation mechanisms during disease progression. This encouraging preclinical data could be translated into novel therapeutic options for neurodegenerative disorders such as PD.
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15
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Human telomerase reverse transcriptase positively regulates mitophagy by inhibiting the processing and cytoplasmic release of mitochondrial PINK1. Cell Death Dis 2020; 11:425. [PMID: 32513926 PMCID: PMC7280311 DOI: 10.1038/s41419-020-2641-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 05/21/2020] [Accepted: 05/25/2020] [Indexed: 12/18/2022]
Abstract
Mutations in the phosphatase and tensin homologue-induced putative kinase 1 (PINK1) gene have been linked to an early-onset autosomal recessive form of familial Parkinson′s disease (PD). PINK1, a mitochondrial serine/threonine-protein kinase, plays an important role in clearing defective mitochondria by mitophagy – the selective removal of mitochondria through autophagy. Evidence suggests that alteration of the PINK1 pathway contributes to the pathogenesis of PD, but the mechanisms by which the PINK1 pathway regulates mitochondrial quality control through mitophagy remain unclear. Human telomerase reverse transcriptase (hTERT) is a catalytic subunit of telomerase that functions in telomere maintenance as well as several non-telomeric activities. For example, hTERT has been associated with cellular immortalization, cell growth control, and mitochondrial regulation. We determined that hTERT negatively regulates the cleavage and cytosolic processing of PINK1 and enhances its mitochondrial localization by inhibiting mitochondrial processing peptidase β (MPPβ). Consequently, hTERT promotes mitophagy following carbonyl cyanide m-chlorophenylhydrazone (CCCP)-induced mitochondrial dysfunction and improves the function of damaged mitochondria by modulating PINK1. These findings suggest that hTERT positively regulates PINK1 function, leading to increased mitophagy following mitochondrial damage.
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16
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Ding X, Liu X, Wang F, Wang F, Geng X. Role of Senescence and Neuroprotective Effects of Telomerase in Neurodegenerative Diseases. Rejuvenation Res 2020; 23:150-158. [DOI: 10.1089/rej.2018.2115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Xuelu Ding
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, China
| | - Xuewen Liu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, China
| | - Feng Wang
- Department of Genetics, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Fei Wang
- Department of Neurology, General Hospital, Tianjin Medical University, Tianjin, China
| | - Xin Geng
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
- Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Tianjin Medical University, Tianjin, China
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17
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Mahoney ER, Dumitrescu L, Seto M, Nudelman KNH, Buckley RF, Gifford KA, Saykin AJ, Jefferson AJ, Hohman TJ. Telomere length associations with cognition depend on Alzheimer's disease biomarkers. ALZHEIMERS & DEMENTIA-TRANSLATIONAL RESEARCH & CLINICAL INTERVENTIONS 2019; 5:883-890. [PMID: 31890852 PMCID: PMC6926345 DOI: 10.1016/j.trci.2019.11.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Introduction While telomere shortening, a marker of cellular aging, may impact the progression of age-related neurodegenerative diseases, its association with cognition is unclear, particularly in the context of Alzheimer's disease (AD) pathology. Methods Telomere, cognitive, and CSF data from 482 participants in the AD Neuroimaging Initiative (148 cognitively normal, 283 mild cognitive impairment, 51 AD) was leveraged to assess telomere length associations with cognition (measured by memory and executive function) and interactions with CSF amyloid-β, tau, and APOE -ε4. Secondary analyses assessed brain volume and thickness outcomes. Results Longer telomeres at baseline were associated with faster executive function decline. Amyloid-β and tau interacted with telomere length on cognition, with longer telomeres related to faster decline among biomarker-positive individuals. Discussion Telomere associations with cognition shift with AD progression, with longer telomeres related to worse outcomes as pathology increases, highlighting the need for further investigation of telomere length along the AD neuropathological cascade.
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Affiliation(s)
- Emily R Mahoney
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Logan Dumitrescu
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Mabel Seto
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Kelly N H Nudelman
- Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Rachel F Buckley
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Katie A Gifford
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Andrew J Saykin
- Department of Radiology & Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Angela J Jefferson
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Timothy J Hohman
- Vanderbilt Memory and Alzheimer's Center, Vanderbilt University Medical Center, Nashville, TN, USA.,Vanderbilt Genetics Institute, Vanderbilt University Medical Center, Nashville, TN, USA
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18
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Telomerase increasing compound protects hippocampal neurons from amyloid beta toxicity by enhancing the expression of neurotrophins and plasticity related genes. Sci Rep 2019; 9:18118. [PMID: 31792359 PMCID: PMC6889131 DOI: 10.1038/s41598-019-54741-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 10/03/2019] [Indexed: 12/31/2022] Open
Abstract
The telomerase reverse transcriptase protein, TERT, is expressed in the adult brain and its exogenic expression protects neurons from oxidative stress and from the cytotoxicity of amyloid beta (Aβ). We previously showed that telomerase increasing compounds (AGS) protected neurons from oxidative stress. Therefore, we suggest that increasing TERT by AGS may protect neurons from the Aβ-induced neurotoxicity by influencing genes and factors that participate in neuronal survival and plasticity. Here we used a primary hippocampal cell culture exposed to aggregated Aβ and hippocampi from adult mice. AGS treatment transiently increased TERT gene expression in hippocampal primary cell cultures in the presence or absence of Aβ and protected neurons from Aβ induced neuronal degradation. An increase in the expression of Growth associated protein 43 (GAP43), and Feminizing locus on X-3 genes (NeuN), in the presence or absence of Aβ, and Synaptophysin (SYP) in the presence of Aβ was observed. GAP43, NeuN, SYP, Neurotrophic factors (NGF, BDNF), beta-catenin and cyclin-D1 expression were increased in the hippocampus of AGS treated mice. This data suggests that increasing TERT by pharmaceutical compounds partially exerts its neuroprotective effect by enhancing the expression of neurotrophic factors and neuronal plasticity genes in a mechanism that involved Wnt/beta-catenin pathway.
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19
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Günes C, Wezel F, Southgate J, Bolenz C. Implications of TERT promoter mutations and telomerase activity in urothelial carcinogenesis. Nat Rev Urol 2019; 15:386-393. [PMID: 29599449 DOI: 10.1038/s41585-018-0001-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Telomerase activity imparts eukaryotic cells with unlimited proliferation capacity, one of the cancer hallmarks. Over 90% of human urothelial carcinoma of the bladder (UCB) tumours are positive for telomerase activity. Telomerase activation can occur through several mechanisms. Mutations in the core promoter region of the human telomerase reverse transcriptase gene (TERT) cause telomerase reactivation in 60-80% of UCBs, whereas the prevalence of these mutations is lower in urothelial cancers of other origins. TERT promoter mutations are the most frequent genetic alteration across all stages of UCB, indicating a strong selection pressure during neoplastic transformation. TERT promoter mutations could arise during regeneration of normal urothelium and, owing to consequential telomerase reactivation, might be the basis of UCB initiation, which represents a new model of urothelial cancer origination. In the future, TERT promoter mutations and telomerase activity might have diagnostic and therapeutic applications in UCB.
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Affiliation(s)
- Cagatay Günes
- Department of Urology, University of Ulm, Ulm, Germany.
| | - Felix Wezel
- Department of Urology, University of Ulm, Ulm, Germany
| | - Jennifer Southgate
- Department of Biology, Jack Birch Unit of Molecular Carcinogenesis, University of York, York, UK
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20
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Bignoux MJ, Cuttler K, Otgaar TC, Ferreira E, Letsolo BT, Weiss SF. LRP::FLAG Rescues Cells from Amyloid-β-Mediated Cytotoxicity Through Increased TERT Levels and Telomerase Activity. J Alzheimers Dis 2019; 69:729-741. [DOI: 10.3233/jad-190075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Monique J. Bignoux
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Katelyn Cuttler
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Tyrone C. Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Boitelo T. Letsolo
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
| | - Stefan F.T. Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, South Africa
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21
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Ferreira E, Bignoux MJ, Otgaar TC, Tagliatti N, Jovanovic K, Letsolo BT, Weiss SFT. LRP/LR specific antibody IgG1-iS18 impedes neurodegeneration in Alzheimer's disease mice. Oncotarget 2018; 9:27059-27073. [PMID: 29930750 PMCID: PMC6007457 DOI: 10.18632/oncotarget.25473] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 05/08/2018] [Indexed: 11/25/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disease caused by accumulation of amyloid beta (Aβ) plaque and neurofibrillary tangle formation. We have shown in vitro, that knock-down and blockade of the 37 kDa/67 kDa Laminin Receptor (LRP/LR) resulted in reduced Aβ induced cytotoxicity and Aβ accumulation. In order to test the effect of blocking LRP/LR on Aβ formation and AD associated symptoms, AD transgenic mice received the anti-LRP/LR specific antibody, IgG1-iS18 through intranasal administration. We show that this treatment resulted in an improvement in memory, and decreased Aβ plaque formation. Moreover, a significant decrease in Aβ42 protein expression with a concomitant increase in amyloid precursor protein (APP) and telomerase reverse transcriptase (mTERT) levels was observed. These data recommend IgG1-iS18 as a potentially powerful therapeutic antibody for AD treatment.
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Affiliation(s)
- Eloise Ferreira
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Monique J Bignoux
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Tyrone C Otgaar
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Nicolas Tagliatti
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Katarina Jovanovic
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa.,Present address: UCL Institute of Ophthalmology, London, UK
| | - Boitelo T Letsolo
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Stefan F T Weiss
- School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Republic of South Africa
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22
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Liu MY, Nemes A, Zhou QG. The Emerging Roles for Telomerase in the Central Nervous System. Front Mol Neurosci 2018; 11:160. [PMID: 29867352 PMCID: PMC5964194 DOI: 10.3389/fnmol.2018.00160] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/26/2018] [Indexed: 12/11/2022] Open
Abstract
Telomerase, a specialized ribonucleoprotein enzyme complex, maintains telomere length at the 3′ end of chromosomes, and functions importantly in stem cells, cancer and aging. Telomerase exists in neural stem cells (NSCs) and neural progenitor cells (NPCs), at a high level in the developing and adult brains of humans and rodents. Increasing studies have demonstrated that telomerase in NSCs/NPCs plays important roles in cell proliferation, neuronal differentiation, neuronal survival and neuritogenesis. In addition, recent works have shown that telomerase reverse transcriptase (TERT) can protect newborn neurons from apoptosis and excitotoxicity. However, to date, the link between telomerase and diseases in the central nervous system (CNS) is not well reviewed. Here, we analyze the evidence and summarize the important roles of telomerase in the CNS. Understanding the roles of telomerase in the nervous system is not only important to gain further insight into the process of the neural cell life cycle but would also provide novel therapeutic applications in CNS diseases such as neurodegenerative condition, mood disorders, aging and other ailments.
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Affiliation(s)
- Meng-Ying Liu
- Department of Clinical Pharmacology, Pharmacy College, Nanjing Medical University, Nanjing, China.,The Affiliated Hospital of Nanjing University Medical School, Nanjing Drum Tower Hospital, Nanjing, China
| | - Ashley Nemes
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Qi-Gang Zhou
- Department of Clinical Pharmacology, Pharmacy College, Nanjing Medical University, Nanjing, China.,Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
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23
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The Effect of Electroacupuncture versus Manual Acupuncture through the Expression of TrkB/NF- κB in the Subgranular Zone of the Dentate Gyrus of Telomerase-Deficient Mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:1013978. [PMID: 29849690 PMCID: PMC5937603 DOI: 10.1155/2018/1013978] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 03/07/2018] [Indexed: 02/06/2023]
Abstract
Our previous study showed that the acupuncture stimulation on the acupoint (ST-36) could activate the brain-derived neurotropic factor (BDNF) signaling pathways in telomerase-deficient mice. Recently, we set out to investigate whether the manual acupuncture (MA) or electroacupuncture (EA) displays a therapeutic advantage on age-related deterioration of learning and memory. Both telomerase-deficient mice (Terc−/− group, n = 24) and wild-type mice (WT group, n = 24) were randomly assigned to 3 subgroups (CON, controls with no treatment; MA, mice receiving manual acupuncture; EA, mice receiving electric acupuncture). The mice were subjected to behavior test, and EA/MA were applied at bilateral acupoints (ST36) 30 min daily for 7 successive days. The brain tissues were collected after the last Morris water maze (MWM) test and were subjected to the immunohistochemistry and western blot analysis. The MWM test showed that EA can significantly increase the time in target quadrant (P ≤ 0.01) and frequency of locating platform for Terc−/− mice (P ≤ 0.05), while nothing changed in WT mice. Furthermore, western blotting and immunohistochemistry suggested that EA could also specifically increase the expression of TrkB and NF-κB in Terc−/− mice but not in wild-type mice (P ≤ 0.05). Meanwhile, the expression level and ratio of ERK/p-ERK did not exhibit significant changes in each subgroup. These results indicated that, compared with MA, the application of EA could specifically ameliorate the spatial learning and memory capability for telomerase-deficient mice through the activation of TrkB and NF-κB.
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24
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Bui AD, Sharma R, Henkel R, Agarwal A. Reactive oxygen species impact on sperm DNA and its role in male infertility. Andrologia 2018; 50:e13012. [DOI: 10.1111/and.13012] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2018] [Indexed: 02/07/2023] Open
Affiliation(s)
- A. D. Bui
- American Center for Reproductive Medicine; Cleveland Clinic; Cleveland OH USA
- Ohio University Heritage College of Osteopathic Medicine; Athens OH USA
| | - R. Sharma
- American Center for Reproductive Medicine; Cleveland Clinic; Cleveland OH USA
| | - R. Henkel
- Department of Medical Bioscience; University of the Western Cape; Bellville South Africa
| | - A. Agarwal
- American Center for Reproductive Medicine; Cleveland Clinic; Cleveland OH USA
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25
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Hehar H, Ma I, Mychasiuk R. Intergenerational Transmission of Paternal Epigenetic Marks: Mechanisms Influencing Susceptibility to Post-Concussion Symptomology in a Rodent Model. Sci Rep 2017; 7:7171. [PMID: 28769086 PMCID: PMC5541091 DOI: 10.1038/s41598-017-07784-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/30/2017] [Indexed: 01/29/2023] Open
Abstract
Epigenetic transmission of phenotypic variance has been linked to paternal experiences prior to conception and during perinatal development. Previous reports indicate that paternal experiences increase phenotypic heterogeneity and may contribute to offspring susceptibility to post-concussive symptomology. This study sought to determine if epigenetic tags, specifically DNA methylation of promoter regions, are transmitted from rodent fathers to their sons. Using MethyLight, promoter methylation of specific genes involved in recovery from concussion and brain plasticity were analyzed in sperm and brain tissue. Promoter methylation in sperm differed based on paternal experience. Differences in methylation were often identified in both the sperm and brain tissue obtained from their sons, demonstrating transmission of epigenetic tags. For certain genes, methylation in the sperm was altered following a concussion suggesting that a history of brain injury may influence paternal transmission of traits. As telomere length is paternally inherited and linked to neurological health, this study examined paternally derived differences in telomere length, in both sperm and brain. Telomere length was consistent between fathers and their sons, and between brain and sperm, with the exception of the older fathers. Older fathers exhibited increased sperm telomere length, which was not evident in sperm or brain of their sons.
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Affiliation(s)
- Harleen Hehar
- Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Department of Psychology, Calgary, Alberta, Canada
| | - Irene Ma
- Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Department of Psychology, Calgary, Alberta, Canada
| | - Richelle Mychasiuk
- Alberta Children's Hospital Research Institute, Hotchkiss Brain Institute, University of Calgary, Department of Psychology, Calgary, Alberta, Canada.
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26
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Manipulating cognitive reserve: Pre-injury environmental conditions influence the severity of concussion symptomology, gene expression, and response to melatonin treatment in rats. Exp Neurol 2017; 295:55-65. [PMID: 28579327 DOI: 10.1016/j.expneurol.2017.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/21/2017] [Accepted: 06/01/2017] [Indexed: 11/22/2022]
Abstract
In an effort to understand the factors that contribute to heterogeneity in outcomes often associated with mTBI in youth, this study examined the role of premorbid differences in cognitive reserve on post-concussive symptoms (PCS), molecular markers, and treatment response. Male and female rats matured in one of three environmental conditions (Stress, Enrichment, Control), received a mTBI in adolescence, and were randomized to melatonin or placebo treatment. All animals underwent a behavioural test battery designed to examine PCS. Using prefrontal cortex and hippocampus tissue, expression of 9 genes was assessed in an effort to determine how the brain's epigenome was influenced by cognitive reserve, mTBI, and melatonin. Enrichment increased cognitive reserve (CR) and prevented lingering symptoms. Conversely, stress was associated with progressive worsening and manifestation of PCS in the longer-term. Melatonin was able to restore baseline function for control and enriched animals, but was ineffective for the stress condition. Epigenetic change in the prefrontal cortex was largely driven by the injury, while gene expression changes in the hippocampus were dependent upon cognitive reserve. The occurrence and severity of PCS is dependent upon a complex and multifaceted array of factors that modify behavioural and epigenetic responses to mTBI and its treatment.
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27
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G-Quadruplex surveillance in BCL-2 gene: a promising therapeutic intervention in cancer treatment. Drug Discov Today 2017; 22:1165-1186. [PMID: 28506718 DOI: 10.1016/j.drudis.2017.05.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 03/20/2017] [Accepted: 05/05/2017] [Indexed: 02/07/2023]
Abstract
Recently, therapeutic implications of BCL-2 quadruplex invigorated the field of clinical oncology. This Keynote review discusses how a BCL-2 quadruplex-selective approach circumvents the limitations of existing therapeutics; and which improvisations might ameliorate the recent trends of quadruplex-based treatment.
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28
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Im E, Yoon JB, Lee HW, Chung KC. Human Telomerase Reverse Transcriptase (hTERT) Positively Regulates 26S Proteasome Activity. J Cell Physiol 2017; 232:2083-2093. [PMID: 27648923 DOI: 10.1002/jcp.25607] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/19/2016] [Indexed: 02/02/2023]
Abstract
Human telomerase reverse transcriptase (hTERT) is the catalytic subunit of telomerase, an RNA-dependent DNA polymerase that elongates telomeric DNA. hTERT displays several extra-telomeric functions that are independent of its telomere-regulatory function, including tumor progression, and neuronal cell death regulation. In this study, we evaluated these additional hTERT non-telomeric functions. We determined that hTERT interacts with several 19S and 20S proteasome subunits. The 19S regulatory particle and 20S core particle are part of 26S proteasome complex, which plays a central role in ubiquitin-dependent proteolysis. In addition, hTERT positively regulated 26S proteasome activity independent of its enzymatic activity. Moreover, hTERT enhanced subunit interactions, which may underlie hTERT's ability of hTERT to stimulate the 26S proteasome. Furthermore, hTERT displayed cytoprotective effect against ER stress via the activation of 26S proteasome in acute myeloid leukemia cells. Our data suggest that hTERT acts as a novel chaperone to promote 26S proteasome assembly and maintenance. J. Cell. Physiol. 232: 2083-2093, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Eunju Im
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Jong Bok Yoon
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Kwang Chul Chung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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29
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Mychasiuk R, Hehar H, Ma I, Candy S, Esser MJ. Reducing the time interval between concussion and voluntary exercise restores motor impairment, short-term memory, and alterations to gene expression. Eur J Neurosci 2016; 44:2407-2417. [DOI: 10.1111/ejn.13360] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Richelle Mychasiuk
- Alberta Children's Hospital Research Institute; Department of Psychology; University of Calgary; Heritage Medical Research Building, 3330 Hospital Drive NW Calgary AB T2N 1N4 Canada
| | - Harleen Hehar
- Alberta Children's Hospital Research Institute; Department of Psychology; University of Calgary; Heritage Medical Research Building, 3330 Hospital Drive NW Calgary AB T2N 1N4 Canada
| | - Irene Ma
- Alberta Children's Hospital Research Institute; Department of Psychology; University of Calgary; Heritage Medical Research Building, 3330 Hospital Drive NW Calgary AB T2N 1N4 Canada
| | - Sydney Candy
- Alberta Children's Hospital Research Institute; Faculty of Medicine; University of Calgary; Calgary AB Canada
| | - Michael J. Esser
- Alberta Children's Hospital Research Institute; Faculty of Medicine; University of Calgary; Calgary AB Canada
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Inhibition of telomerase causes vulnerability to endoplasmic reticulum stress-induced neuronal cell death. Neurosci Lett 2016; 629:241-244. [PMID: 27443785 DOI: 10.1016/j.neulet.2016.07.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/27/2016] [Accepted: 07/16/2016] [Indexed: 01/01/2023]
Abstract
Endoplasmic reticulum (ER) stress is implicated in several diseases, such as cancer and neurodegenerative diseases. In the present study, we investigated the possible involvement of telomerase in ER stress-induced cell death. ER stress-induced cell death was ameliorated in telomerase reverse transcriptase (TERT) over-expressing MCF7 cells (MCF7-TERT cell). Telomerase specific inhibitor, BIBR1532, reversed the inhibitory effect of TERT on ER stress-induced cell death in MCF7-TERT cells. These findings suggest that BIBR1532 may specifically inhibit telomerase activity, thereby inducing cell death in ER stress-exposed cells. TERT was expressed in the SH-SY5Y neuroblastoma cell line. To analyze the possible involvement of telomerase in ER stress-induced neuronal cell death, we treated SH-SY5Y neuroblastoma cells with BIBR1532 and analyzed ER stress-induced cell death. We found that BIBR1532 significantly enhanced the ER stress-induced neuronal cell death. These findings suggest that inhibition of telomerase activity may enhance vulnerability to neuronal cell death caused by ER stress.
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Effect of paternal overweight or obesity on IVF treatment outcomes and the possible mechanisms involved. Sci Rep 2016; 6:29787. [PMID: 27412918 PMCID: PMC4944201 DOI: 10.1038/srep29787] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 06/21/2016] [Indexed: 01/09/2023] Open
Abstract
Leukocyte telomere lengths (LTLs) are shorter in obese compared with normal weight people. However, it is not known whether sperm telomere length (STL) is related to obesity. The aim of the study was to evaluate the impact of men’s body mass index (BMI) on STL, embryo quality, and clinical outcomes in couples undergoing IVF. In total, 651 couples were recruited, including 345 men with a normal BMI and 306 men with an overweight BMI (normal BMI group: 20–25 kg/m2; overweight BMI group: >28 kg/m2). We found that couples with male’s BMI over 28 kg/m2 exhibited a significantly lower fertilization rate, good-quality embryo rate and clinical pregnancy rate compared to their normal BMI counterparts. The mean STL in the overweight BMI group was also significantly shorter than that of the normal BMI group. The results also showed that individuals with higher BMI had higher ROS (Reactive oxygen species) content and sperm DNA fragmentation rate when compared with normal BMI individuals. Mitochondrial activity was also lower in the overweight BMI group than in the normal BMI group. This is the first report to find that STL is shorter in overweight/obese men, which may account for their poorer treatment outcomes in IVF cycles.
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González-Giraldo Y, Forero DA, Echeverria V, Gonzalez J, Ávila-Rodriguez M, Garcia-Segura LM, Barreto GE. Neuroprotective effects of the catalytic subunit of telomerase: A potential therapeutic target in the central nervous system. Ageing Res Rev 2016; 28:37-45. [PMID: 27095058 DOI: 10.1016/j.arr.2016.04.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 12/15/2022]
Abstract
Senescence plays an important role in neurodegenerative diseases and involves key molecular changes induced by several mechanisms such as oxidative stress, telomere shortening and DNA damage. Potential therapeutic strategies directed to counteract these molecular changes are of great interest for the prevention of the neurodegenerative process. Telomerase is a ribonucleoprotein composed of a catalytic subunit (TERT) and a RNA subunit (TERC). It is known that the telomerase is involved in the maintenance of telomere length and is a highly expressed protein in embryonic stages and decreases in adult cells. In the last decade, a growing number of studies have shown that TERT has neuroprotective effects in cellular and animal models after a brain injury. Significantly, differences in TERT expression between controls and patients with major depressive disorder have been observed. More recently, TERT has been associated with the decrease in reactive oxygen species and DNA protection in mitochondria of neurons. In this review, we highlight the role of TERT in some neurodegenerative disorders and discuss some studies focusing on this protein as a potential target for neuroprotective therapies.
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Affiliation(s)
- Yeimy González-Giraldo
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - Diego A Forero
- Laboratory of Neuropsychiatric Genetics, Biomedical Sciences Research Group, School of Medicine, Universidad Antonio Nariño, Bogotá, Colombia
| | - Valentina Echeverria
- Facultad de Ciencias de la Salud, Universidad San Sebastián, Lientur 1457, Concepción, Chile
| | - Janneth Gonzalez
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | | | | | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile; Universidad Científica del Sur, Lima, Peru.
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Telomerase Activity is Downregulated Early During Human Brain Development. Genes (Basel) 2016; 7:genes7060027. [PMID: 27322326 PMCID: PMC4929426 DOI: 10.3390/genes7060027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 05/25/2016] [Accepted: 06/06/2016] [Indexed: 12/14/2022] Open
Abstract
Changes in hTERT splice variant expression have been proposed to facilitate the decrease of telomerase activity during fetal development in various human tissues. Here, we analyzed the expression of telomerase RNA (hTR), wild type and α-spliced hTERT in developing human fetal brain (post conception weeks, pcw, 6-19) and in young and old cortices using qPCR and correlated it to telomerase activity measured by TRAP assay. Decrease of telomerase activity occurred early during brain development and correlated strongest to decreased hTR expression. The expression of α-spliced hTERT increased between pcw 10 and 19, while that of wild type hTERT remained unchanged. Lack of expression differences between young and old cortices suggests that most changes seem to occur early during human brain development. Using in vitro differentiation of neural precursor stem cells (NPSCs) derived at pcw 6 we found a decrease in telomerase activity but no major expression changes in telomerase associated genes. Thus, they do not seem to model the mechanisms for the decrease in telomerase activity in fetal brains. Our results suggest that decreased hTR levels, as well as transient increase in α-spliced hTERT, might both contribute to downregulation of telomerase activity during early human brain development between 6 and 17 pcw.
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Babizhayev MA, Yegorov YE. Tissue formation and tissue engineering through host cell recruitment or a potential injectable cell-based biocomposite with replicative potential: Molecular mechanisms controlling cellular senescence and the involvement of controlled transient telomerase activation therapies. J Biomed Mater Res A 2015; 103:3993-4023. [PMID: 26034007 DOI: 10.1002/jbm.a.35515] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 05/18/2015] [Indexed: 01/04/2023]
Abstract
Accumulated data indicate that wound-care products should have a composition equivalent to that of the skin: a combination of particular growth factors and extracellular matrix (ECM) proteins endogenous to the skin, together with viable epithelial cells, fibroblasts, and mesenchymal stem cells (MSCs). Strategies consisting of bioengineered dressings and cell-based products have emerged for widespread clinical use; however, their performance is not optimal because chronic wounds persist as a serious unmet medical need. Telomerase, the ribonucleoprotein complex that adds telomeric repeats to the ends of chromosomes, is responsible for telomere maintenance, and its expression is associated with cell immortalization and, in certain cases, cancerogenesis. Telomerase contains a catalytic subunit, the telomerase reverse transcriptase (hTERT). Introduction of TERT into human cells extends both their lifespan and their telomeres to lengths typical of young cells. The regulation of TERT involves transcriptional and posttranscriptional molecular biology mechanisms. The manipulation, regulation of telomerase is multifactorial in mammalian cells, involving overall telomerase gene expression, post-translational protein-protein interactions, and protein phosphorylation. Reactive oxygen species (ROS) have been implicated in aging, apoptosis, and necrosis of cells in numerous diseases. Upon production of high levels of ROS from exogenous or endogenous generators, the redox balance is perturbed and cells are shifted into a state of oxidative stress, which subsequently leads to modifications of intracellular proteins and membrane lipid peroxidation and to direct DNA damage. When the oxidative stress is severe, survival of the cell is dependent on the repair or replacement of damaged molecules, which can result in induction of apoptosis in the injured with ROS cells. ROS-mediated oxidative stress induces the depletion of hTERT from the nucleus via export through the nuclear pores. Nuclear export is initiated by ROS-induced phosphorylation of tyrosine 707 within hTERT by the Src kinase family. It might be presumed that protection of mitochondria against oxidative stress is an important telomere length-independent function for telomerase in cell survival. Biotechnology companies are focused on development of therapeutic telomerase vaccines, telomerase inhibitors, and telomerase promoter-driven cell killing in oncology, have a telomerase antagonist in late preclinical studies. Anti-aging medicine-oriented groups have intervened on the market with products working on telomerase activation for a broad range of degenerative diseases in which replicative senescence or telomere dysfunction may play an important role. Since oxidative damage has been shown to shorten telomeres in tissue culture models, the adequate topical, transdermal, or systemic administration of antioxidants (such as, patented ocular administration of 1% N-acetylcarnosine lubricant eye drops in the treatment of cataracts) may be beneficial at preserving telomere lengths and delaying the onset or in treatment of disease in susceptible individuals. Therapeutic strategies toward controlled transient activation of telomerase are targeted to cells and replicative potential in cell-based therapies, tissue engineering and regenerative medicine.
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Affiliation(s)
- Mark A Babizhayev
- Innovative Vision Products, Inc., 3511 Silverside Road, Suite 105, County of New Castle, Delaware, 19810
| | - Yegor E Yegorov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov Street, Moscow, 119991, Russian Federation
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Boccardi V, Pelini L, Ercolani S, Ruggiero C, Mecocci P. From cellular senescence to Alzheimer's disease: The role of telomere shortening. Ageing Res Rev 2015; 22:1-8. [PMID: 25896211 DOI: 10.1016/j.arr.2015.04.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 04/13/2015] [Accepted: 04/15/2015] [Indexed: 11/17/2022]
Abstract
The old age population is increasing worldwide as well as age related diseases, including neurodegenerative disorders, such as Alzheimer's disease (AD), which negatively impacts on the health care systems. Aging represents per se a risk factor for AD. Thus, the study and identification of pathways within the biology of aging represent an important end point for the development of novel and effective disease-modifying drugs to treat, delay, or prevent AD. Cellular senescence and telomere shortening represent suitable and promising targets. Several studies show that cellular senescence is tightly interconnected to aging and AD, while the role of telomere dynamic and stability in AD pathogenesis is still unclear. This review will focus on the linking mechanisms between cellular senescence, telomere shortening, and AD.
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Affiliation(s)
- Virginia Boccardi
- Institute of Gerontology and Geriatrics, Department of Medicine, University of Perugia, Perugia, Italy.
| | - Luca Pelini
- Institute of Gerontology and Geriatrics, Department of Medicine, University of Perugia, Perugia, Italy
| | - Sara Ercolani
- Institute of Gerontology and Geriatrics, Department of Medicine, University of Perugia, Perugia, Italy
| | - Carmelinda Ruggiero
- Institute of Gerontology and Geriatrics, Department of Medicine, University of Perugia, Perugia, Italy
| | - Patrizia Mecocci
- Institute of Gerontology and Geriatrics, Department of Medicine, University of Perugia, Perugia, Italy
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Wolkowitz OM, Mellon SH, Lindqvist D, Epel ES, Blackburn EH, Lin J, Reus VI, Burke H, Rosser R, Mahan L, Mackin S, Yang T, Weiner M, Mueller S. PBMC telomerase activity, but not leukocyte telomere length, correlates with hippocampal volume in major depression. Psychiatry Res 2015; 232:58-64. [PMID: 25773002 PMCID: PMC4404215 DOI: 10.1016/j.pscychresns.2015.01.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/02/2014] [Accepted: 01/09/2015] [Indexed: 11/29/2022]
Abstract
Accelerated cell aging, indexed in peripheral leukocytes by telomere shortness and in peripheral blood mononuclear cells (PBMCs) by telomerase activity, has been reported in several studies of major depressive disorder (MDD). However, the relevance of these peripheral measures for brain indices that are presumably more directly related to MDD pathophysiology is unknown. In this study, we explored the relationship between PBMC telomerase activity and leukocyte telomere length and magnetic resonance imaging-estimated hippocampal volume in un-medicated depressed individuals and healthy controls. We predicted that, to the extent peripheral and central telomerase activity are directly related, PBMC telomerase activity would be positively correlated with hippocampal volume, perhaps due to hippocampal telomerase-associated neurogenesis, neuroprotection or neurotrophic facilitation, and that this effect would be clearer in individuals with increased PBMC telomerase activity, as previously reported in un-medicated MDD. We did not have specific hypotheses regarding the relationship between leukocyte telomere length and hippocampal volume, due to conflicting reports in the published literature. We found, in 25 un-medicated MDD subjects, that PBMC telomerase activity was significantly positively correlated with hippocampal volume; this relationship was not observed in 18 healthy controls. Leukocyte telomere length was not significantly related to hippocampal volume in either group (19 unmedicated MDD subjects and 17 healthy controls). Although the nature of the relationship between peripheral telomerase activity and telomere length and the hippocampus is unclear, these preliminary data are consistent with the possibility that PBMC telomerase activity indexes, and may provide a novel window into, hippocampal neuroprotection and/or neurogenesis in MDD.
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Affiliation(s)
- Owen M. Wolkowitz
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
,Corresponding author: Dept. of Psychiatry, UCSF School of Medicine, 401 Parnassus Ave., San Francisco, CA 94143-0983, USA. Tel.: +1 (415) 476-7433; Fax: +1 (415) 502-2661;
| | - Synthia H. Mellon
- Department of OBGYN and Reproductive Endocrinology, UCSF School of Medicine, San Francisco, CA, USA
| | - Daniel Lindqvist
- Department of Clinical Sciences, Section for Psychiatry, Lund University, Lund, Sweden
| | - Elissa S. Epel
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Elizabeth H. Blackburn
- Department of Physiology and Biochemistry, UCSF School of Medicine, San Francisco, CA, USA
| | - Jue Lin
- Department of Physiology and Biochemistry, UCSF School of Medicine, San Francisco, CA, USA
| | - Victor I. Reus
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Heather Burke
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Rebecca Rosser
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Laura Mahan
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Scott Mackin
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Tony Yang
- Department of Psychiatry, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Michael Weiner
- Department of Radiology, UCSF School of Medicine, and San Francisco Veterans Administration Medical Center, San Francisco, CA, USA
| | - Susanne Mueller
- Department of Radiology, UCSF School of Medicine, and San Francisco Veterans Administration Medical Center, San Francisco, CA, USA
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The role of telomerase protein TERT in Alzheimer's disease and in tau-related pathology in vitro. J Neurosci 2015; 35:1659-74. [PMID: 25632141 DOI: 10.1523/jneurosci.2925-14.2015] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The telomerase reverse transcriptase protein TERT has recently been demonstrated to have a variety of functions both in vitro and in vivo, which are distinct from its canonical role in telomere extension. In different cellular systems, TERT protein has been shown to be protective through its interaction with mitochondria. TERT has previously been found in rodent neurons, and we hypothesize that it might have a protective function in adult human brain. Here, we investigated the expression of TERT at different stages of Alzheimer's disease pathology (Braak Stages I-VI) in situ and the ability of TERT to protect against oxidative damage in an in vitro model of tau pathology. Our data reveal that TERT is expressed in vitro in mouse neurons and microglia, and in vivo in the cytoplasm of mature human hippocampal neurons and activated microglia, but is absent from astrocytes. Intriguingly, hippocampal neurons expressing TERT did not contain hyperphosphorylated tau. Vice versa, neurons that expressed high levels of pathological tau did not appear to express TERT protein. TERT protein colocalized with mitochondria in the hippocampus of Alzheimer's disease brains (Braak Stage VI), as well as in cultured neurons under conditions of oxidative stress. Our in vitro data suggest that the absence of TERT increases ROS generation and oxidative damage in neurons induced by pathological tau. Together, our findings suggest that TERT protein persists in neurons of the adult human brain, where it may have a protective role against tau pathology.
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Wang J, Zhao C, Zhao A, Li M, Ren J, Qu X. New Insights in Amyloid Beta Interactions with Human Telomerase. J Am Chem Soc 2015; 137:1213-9. [DOI: 10.1021/ja511030s] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jiasi Wang
- Laboratory
of Chemical Biology
and Division of Biological Inorganic Chemistry, State Key Laboratory
of Rare Earth Resource Utilization, Changchun Institute of Applied
Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Chuanqi Zhao
- Laboratory
of Chemical Biology
and Division of Biological Inorganic Chemistry, State Key Laboratory
of Rare Earth Resource Utilization, Changchun Institute of Applied
Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Andong Zhao
- Laboratory
of Chemical Biology
and Division of Biological Inorganic Chemistry, State Key Laboratory
of Rare Earth Resource Utilization, Changchun Institute of Applied
Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Meng Li
- Laboratory
of Chemical Biology
and Division of Biological Inorganic Chemistry, State Key Laboratory
of Rare Earth Resource Utilization, Changchun Institute of Applied
Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Jinsong Ren
- Laboratory
of Chemical Biology
and Division of Biological Inorganic Chemistry, State Key Laboratory
of Rare Earth Resource Utilization, Changchun Institute of Applied
Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Xiaogang Qu
- Laboratory
of Chemical Biology
and Division of Biological Inorganic Chemistry, State Key Laboratory
of Rare Earth Resource Utilization, Changchun Institute of Applied
Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Changchun, Jilin 130022, China
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Mychasiuk R, Hehar H, Ma I, Kolb B, Esser MJ. The development of lasting impairments: a mild pediatric brain injury alters gene expression, dendritic morphology, and synaptic connectivity in the prefrontal cortex of rats. Neuroscience 2014; 288:145-55. [PMID: 25555930 DOI: 10.1016/j.neuroscience.2014.12.034] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 01/04/2023]
Abstract
Apart from therapeutic discovery, the study of mild traumatic brain injury (mTBI) has been focused on two challenges: why do a majority of individuals recover with little concern, while a considerable proportion suffer with persistent and often debilitating symptomology; and, how do mild injuries significantly increase risk for an early-onset neurodegeneration? Owing to a lack of observable damage following mTBI, this study was designed to determine if there were changes in neuronal morphology, synaptic connectivity, and epigenetic patterning that could contribute to the manifestation of persistent neurological dysfunction. Prefrontal cortex tissue from male and female rats was used for Golgi-Cox analysis along with the profiling of changes in gene expression (BDNF, DNMT1, FGF2, IGF1, Nogo-A, OXYR, and TERT) and telomere length (TL), following a single mTBI or sham injury in the juvenile period. Golgi-Cox analysis of dendritic branch order, dendritic length, and spine density demonstrate that an early mTBI increases complexity of pyramidal neurons in the mPFC. Furthermore, there are also substantial changes in the expression levels of the seven genes of interest and TL following a single mild injury in this brain region. The results from the neuroanatomical measures and changes in gene expression indicate that the mTBI disrupts normal pruning processes that are typically underway at this point in development. In addition, there are significant interactions between the social environment and epigenetic processes that work in concert to perpetuate neurological dysfunction.
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Affiliation(s)
- R Mychasiuk
- Alberta Children's Hospital Research Institute, University of Calgary, Faculty of Medicine, Calgary, Canada.
| | - H Hehar
- Alberta Children's Hospital Research Institute, University of Calgary, Faculty of Medicine, Calgary, Canada
| | - I Ma
- Alberta Children's Hospital Research Institute, University of Calgary, Faculty of Medicine, Calgary, Canada
| | - B Kolb
- Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Canada
| | - M J Esser
- Alberta Children's Hospital Research Institute, University of Calgary, Faculty of Medicine, Calgary, Canada
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Telomerase expression in amyotrophic lateral sclerosis (ALS) patients. J Hum Genet 2014; 59:555-61. [PMID: 25142509 DOI: 10.1038/jhg.2014.72] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 07/13/2014] [Accepted: 07/17/2014] [Indexed: 01/05/2023]
Abstract
Telomerase and telomeric complex have been linked to a variety of disease states related to neurological dysfunction. In amyotrophic lateral sclerosis (ALS) patients, telomerase activity, as human telomerase reverse transcriptase (hTERT) expression, has not been characterized yet. Here, for the first time, we characterized telomerase and related pathway in blood sample and spinal cord from ALS patients compared with healthy controls. We found that hTERT expression level was significantly lower in ALS patients and was correlated either to p53 mRNA expression or p21 expression, pointing out the hypothesis that telomerase inhibition could be a pathogenetic contributor to neurodegeneration in ALS. As a consequence of the reduced telomerase activity, we identified shorter telomeres in leukocytes from sporadic ALS patients compared with healthy control group.
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Xiao Z, Zhang A, Lin J, Zheng Z, Shi X, Di W, Qi W, Zhu Y, Zhou G, Fang Y. Telomerase: a target for therapeutic effects of curcumin and a curcumin derivative in Aβ1-42 insult in vitro. PLoS One 2014; 9:e101251. [PMID: 24983737 PMCID: PMC4077729 DOI: 10.1371/journal.pone.0101251] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/15/2014] [Indexed: 01/22/2023] Open
Abstract
This study was designed to investigate whether telomerase was involved in the neuroprotective effect of curcumin and Cur1. Alzheimer's disease is a consequence of an imbalance between the generation and clearance of amyloid-beta peptide in the brain. In this study, we used Aβ1-42 (10 µg/ml) to establish a damaged cell model, and curcumin and Cur1 were used in treatment groups. We measured cell survival and cell growth, intracellular oxidative stress and hTERT expression. After RNA interference, the effects of curcumin and Cur1 on cells were verified. Exposure to Aβ1–42 resulted in significant oxidative stress and cell toxicity, and the expression of hTERT was significantly decreased. Curcumin and Cur1 both protected SK-N-SH cells from Aβ1–42 and up-regulated the expression of hTERT. Furthermore, Cur1 demonstrated stronger protective effects than curcumin. However, when telomerase was inhibited by TERT siRNA, the neuroprotection by curcumin and Cur1 were ceased. Our study indicated that the neuroprotective effects of curcumin and Cur1 depend on telomerase, and thus telomerase may be a target for therapeutic effects of curcumin and Cur1.
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Affiliation(s)
- Zijian Xiao
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Aiwu Zhang
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jianwen Lin
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhenyang Zheng
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaolei Shi
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wei Di
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Weiwei Qi
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yingting Zhu
- Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Guijuan Zhou
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yannan Fang
- Department of Neurology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- * E-mail:
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Radan L, Hughes CS, Teichroeb JH, Vieira Zamora FM, Jewer M, Postovit LM, Betts DH. Microenvironmental regulation of telomerase isoforms in human embryonic stem cells. Stem Cells Dev 2014; 23:2046-66. [PMID: 24749509 DOI: 10.1089/scd.2013.0373] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Recent evidence points to extra-telomeric, noncanonical roles for telomerase in regulating stem cell function. In this study, human embryonic stem cells (hESCs) were cultured in 20% or 2% O2 microenvironments for up to 5 days and evaluated for telomerase reverse transcriptase (TERT) expression and telomerase activity. Results showed increased cell survival and maintenance of the undifferentiated state with elevated levels of nuclear TERT in 2% O2-cultured hESCs despite no significant difference in telomerase activity compared with their high-O2-cultured counterparts. Pharmacological inhibition of telomerase activity using a synthetic tea catechin resulted in spontaneous hESC differentiation, while telomerase inhibition with a phosphorothioate oligonucleotide telomere mimic did not. Reverse transcription polymerase chain reaction (RT-PCR) analysis revealed variations in transcript levels of full-length and alternate splice variants of TERT in hESCs cultured under varying O2 atmospheres. Steric-blocking of Δα and Δβ hTERT splicing using morpholino oligonucleotides altered the hTERT splicing pattern and rapidly induced spontaneous hESC differentiation that appeared biased toward endomesodermal and neuroectodermal cell fates, respectively. Together, these results suggest that post-transcriptional regulation of TERT under varying O2 microenvironments may help regulate hESC survival, self-renewal, and differentiation capabilities through expression of extra-telomeric telomerase isoforms.
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Affiliation(s)
- Lida Radan
- 1 Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario , London, Ontario, Canada
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Eitan E, Hutchison ER, Mattson MP. Telomere shortening in neurological disorders: an abundance of unanswered questions. Trends Neurosci 2014; 37:256-63. [PMID: 24698125 PMCID: PMC4008659 DOI: 10.1016/j.tins.2014.02.010] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/24/2014] [Accepted: 02/25/2014] [Indexed: 11/24/2022]
Abstract
Telomeres, ribonucleoprotein complexes that cap eukaryotic chromosomes, typically shorten in leukocytes with aging. Aging is a primary risk factor for neurodegenerative disease (ND), and a common assumption has arisen that leukocyte telomere length (LTL) can serve as a predictor of neurological disease. However, the evidence for shorter LTL in Alzheimer's and Parkinson's patients is inconsistent. The diverse causes of telomere shortening may explain variability in LTL between studies and individuals. Additional research is needed to determine whether neuronal and glial telomeres shorten during aging and in neurodegenerative disorders, if and how LTL is related to brain cell telomere shortening, and whether telomere shortening plays a causal role in or exacerbates neurological disorders.
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Affiliation(s)
- Erez Eitan
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | - Emmette R Hutchison
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Ramakrishnan SK, Varshney A, Sharma A, Das BC, Yadava PK. Expression of targeted ribozyme against telomerase RNA causes altered expression of several other genes in tumor cells. Tumour Biol 2014; 35:5539-50. [PMID: 24664581 DOI: 10.1007/s13277-014-1729-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 02/04/2014] [Indexed: 01/11/2023] Open
Abstract
Telomeres are tandem repeat sequences present at chromosome end that are synthesized by RNA-protein enzyme called telomerase. The RNA component (TR) serves as template for telomerase reverse transcriptase (TERT) for generating telomere repeats. TERT is overexpressed in actively dividing cells including cancerous cells, absent in differentiated somatic cells whereas human telomerase RNA (hTR) is present in normal as well as in cancer cells. Telomerase overexpression in cancer cells ensures telomere length maintenance that actually provides proliferative advantage to cells. Stable expression of ribozyme against hTR in HeLa cells results in reduction of hTR levels, telomerase activity, and telomere length which is accompanied by altered cell morphology and expression of several specific cellular genes. The altered genes deduced from differentially display PCR and 2D gel electrophoresis upon hTR knockdown have function in ribosome biogenesis, chromatin modulation, cell cycle control, and p63-dependant pathways. Our observations shows hTR participates in diverse cellular functions other than telomere maintenance, validates as a possible drug targets in p53- and pRB-negative status, and indicated possible cross-talks between telomerase and other cellular pathways.
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Affiliation(s)
- Suresh Kumar Ramakrishnan
- Applied Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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Abstract
Telomerase reverse transcriptase (TERT) is the protein component of telomerase and combined with an RNA molecule, telomerase RNA component, forms the telomerase enzyme responsible for telomere elongation. Telomerase is essential for maintaining telomere length from replicative attrition and thus contributes to the preservation of genome integrity. Although diverse mouse models have been developed and studied to prove the physiological roles of telomerase as a telomere- elongating enzyme, recent studies have revealed non-canonical TERT activities beyond telomeres. To gain insights into the physiological impact of extra-telomeric roles, this review revisits the strategies and phenotypes of telomerase mouse models in terms of the extra-telomeric functions of telomerase.
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Affiliation(s)
- Young Hoon Sung
- Department of Biochemistry, College of Life Science and Biotechnology, Laboratory Animal Research Center, Yonsei University, Seoul, Korea
| | - Muhammad Ali
- Department of Biochemistry, College of Life Science and Biotechnology, Laboratory Animal Research Center, Yonsei University, Seoul, Korea
| | - Han-Woong Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Laboratory Animal Research Center, Yonsei University, Seoul, Korea
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Li J, Qu Y, Chen D, Zhang L, Zhao F, Luo L, Pan L, Hua J, Mu D. The neuroprotective role and mechanisms of TERT in neurons with oxygen-glucose deprivation. Neuroscience 2013; 252:346-58. [PMID: 23968592 DOI: 10.1016/j.neuroscience.2013.08.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 07/24/2013] [Accepted: 08/09/2013] [Indexed: 01/14/2023]
Abstract
Telomerase reverse transcriptase (TERT) is reported to protect neurons from apoptosis induced by various stresses including hypoxia-ischemia (HI). However, the mechanisms by which TERT exerts its anti-apoptotic role in neurons with HI injury remain unclear. In this study, we examined the protective role and explored the possible mechanisms of TERT in neurons with HI injury in vitro. Primary cultured neurons were exposed to oxygen and glucose deprivation (OGD) for 3h followed by reperfusion to mimic HI injury in vivo. Plasmids containing TERT antisense, sense nucleotides, or mock were transduced into neurons at 48h before OGD. Expression and distribution of TERT were measured by immunofluorescence labeling and western blot. The expression of cleaved caspase 3 (CC3), Bcl-2 and Bax were detected by western blot. Neuronal apoptosis was measured with terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). The mitochondrial reactive oxygen species (ROS) were measured by MitoSOX Red staining. Fluorescent probe JC-1 was used to measure the mitochondrial membrane potential (ΔΨm). We found that TERT expression increased at 8h and peaked at 24h in neurons after OGD. CC3 expression and neuronal apoptosis were induced and peaked at 24h after OGD. TERT inhibition significantly increased CC3 expression and neuronal apoptosis after OGD treatment. Additionally, TERT inhibition decreased the expression ratio of Bcl-2/Bax, and enhanced ROS production and ΔΨm dissipation after OGD. These data suggest that TERT plays a neuroprotective role via anti-apoptosis in neurons after OGD. The underlying mechanisms may be associated with regulating Bcl-2/Bax expression ratio, attenuating ROS generation, and increasing mitochondrial membrane potential.
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Affiliation(s)
- J Li
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, China; Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, 610041 Chengdu, Sichuan, China
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Iannilli F, Zalfa F, Gartner A, Bagni C, Dotti CG. Cytoplasmic TERT Associates to RNA Granules in Fully Mature Neurons: Role in the Translational Control of the Cell Cycle Inhibitor p15INK4B. PLoS One 2013; 8:e66602. [PMID: 23825548 PMCID: PMC3688952 DOI: 10.1371/journal.pone.0066602] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/07/2013] [Indexed: 01/28/2023] Open
Abstract
The main role of Telomerase Reverse Transcriptase (TERT) is to protect telomere length from shortening during cell division. However, recent works have revealed the existence of a pool of TERT associated to mitochondria, where it plays a role in survival. We here show that in fully differentiated neurons the largest pool of cytoplasmic TERT associates to TIA1 positive RNA granules, where it binds the messenger RNA of the cyclin kinase inhibitor p15INK4B. Upon stress, p15INK4B and TERT dissociate and p15INK4B undergoes efficient translation, allowing its pro-survival function. These results unveil another mechanism implicated in the survival of fully differentiated neurons.
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Affiliation(s)
- Francesca Iannilli
- Center for Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Francesca Zalfa
- University of Rome, “Campus Bio-medico” CIR Department, Rome, Italy
| | - Annette Gartner
- Center for Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
- VIB Center for the Biology of Disease – VIB, Leuven, Belgium
| | - Claudia Bagni
- Center for Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
- VIB Center for the Biology of Disease – VIB, Leuven, Belgium
- University of Rome, “Campus Bio-medico” CIR Department, Rome, Italy
| | - Carlos G. Dotti
- Center for Human Genetics, Katholieke Universiteit Leuven, Leuven, Belgium
- VIB Center for the Biology of Disease – VIB, Leuven, Belgium
- Centro de Biología Molecular Severo Ochoa, CSIC/UAM, Madrid, Spain
- * E-mail:
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Smith JA, Park S, Krause JS, Banik NL. Oxidative stress, DNA damage, and the telomeric complex as therapeutic targets in acute neurodegeneration. Neurochem Int 2013; 62:764-75. [PMID: 23422879 DOI: 10.1016/j.neuint.2013.02.013] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 02/04/2013] [Accepted: 02/08/2013] [Indexed: 01/19/2023]
Abstract
Oxidative stress has been identified as an important contributor to neurodegeneration associated with acute CNS injuries and diseases such as spinal cord injury (SCI), traumatic brain injury (TBI), and ischemic stroke. In this review, we briefly detail the damaging effects of oxidative stress (lipid peroxidation, protein oxidation, etc.) with a particular emphasis on DNA damage. Evidence for DNA damage in acute CNS injuries is presented along with its downstream effects on neuronal viability. In particular, unchecked oxidative DNA damage initiates a series of signaling events (e.g. activation of p53 and PARP-1, cell cycle re-activation) which have been shown to promote neuronal loss following CNS injury. These findings suggest that preventing DNA damage might be an effective way to promote neuronal survival and enhance neurological recovery in these conditions. Finally, we identify the telomere and telomere-associated proteins (e.g. telomerase) as novel therapeutic targets in the treatment of neurodegeneration due to their ability to modulate the neuronal response to both oxidative stress and DNA damage.
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Affiliation(s)
- Joshua A Smith
- Division of Neurology, Department of Neurosciences, Medical University of South Carolina, 96 Jonathan Lucas St., Clinical Sciences Building Room 309, Charleston, SC 29425, USA.
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The neuroprotective role of TERT via an antiapoptotic mechanism in neonatal rats after hypoxia–ischemia brain injury. Neurosci Lett 2012; 515:39-43. [DOI: 10.1016/j.neulet.2012.03.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 02/23/2012] [Accepted: 03/05/2012] [Indexed: 11/22/2022]
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50
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Wolkowitz OM, Mellon SH, Epel ES, Lin J, Reus VI, Rosser R, Burke H, Compagnone M, Nelson JC, Dhabhar FS, Blackburn EH. Resting leukocyte telomerase activity is elevated in major depression and predicts treatment response. Mol Psychiatry 2012; 17:164-72. [PMID: 21242992 PMCID: PMC3130817 DOI: 10.1038/mp.2010.133] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Telomeres are DNA-protein complexes that cap linear DNA strands, protecting DNA from damage. When telomeres critically shorten, cells become susceptible to senescence and apoptosis. Telomerase, a cellular ribonucleoprotein enzyme, rebuilds the length of telomeres and promotes cellular viability. Leukocyte telomeres are reportedly shortened in major depression, but telomerase activity in depression has not been previously reported. Further, there are no published reports of the effects of antidepressants on telomerase activity or on the relationship between telomerase activity and antidepressant response. Peripheral blood mononuclear cell (PBMC) telomerase activity was assessed in 20 medication-free depressed individuals and 18 controls. In total, 16 of the depressed individuals were then treated with sertraline in an open-label manner for 8 weeks, and PBMC telomerase activity was reassessed in 15 of these individuals after treatment. Pre- and post-treatment symptom severity was rated with the Hamilton Depression Rating Scale. All analyses were corrected for age and sex. Pre-treatment telomerase activity was significantly elevated in the depressed individuals compared with the controls (P=0.007) and was directly correlated with depression ratings (P<0.05) across all subjects. In the depressed group, individuals with relatively lower pre-treatment telomerase activity and with relatively greater increase in telomerase activity during treatment, showed superior antidepressant responses (P<0.05 and P<0.005, respectively). This is the first report characterizing telomerase activity in depressed individuals. PBMC telomerase activity might reflect a novel aspect of depressive pathophysiology and might represent a novel biomarker of antidepressant responsiveness.
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Affiliation(s)
- OM Wolkowitz
- Department of Psychiatry, University of California, San Francisco (UCSF), School of Medicine, San Francisco, CA, USA
| | - SH Mellon
- Department of OB-GYN and Reproductive Sciences, UCSF School of Medicine, San Francisco, CA, USA
| | - ES Epel
- Department of Psychiatry and Health Psychology Program, UCSF School of Medicine, San Francisco, CA, USA
| | - J Lin
- Department of Biochemistry and Biophysics, UCSF School of Medicine, San Francisco, CA, USA
| | - VI Reus
- Department of Psychiatry, University of California, San Francisco (UCSF), School of Medicine, San Francisco, CA, USA
| | - R Rosser
- Department of Psychiatry, University of California, San Francisco (UCSF), School of Medicine, San Francisco, CA, USA
| | - H Burke
- Department of Psychiatry and Health Psychology Program, UCSF School of Medicine, San Francisco, CA, USA
| | - M Compagnone
- Department of Psychiatry, University of California, San Francisco (UCSF), School of Medicine, San Francisco, CA, USA
| | - JC Nelson
- Department of Psychiatry, University of California, San Francisco (UCSF), School of Medicine, San Francisco, CA, USA
| | - FS Dhabhar
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - EH Blackburn
- Department of Biochemistry and Biophysics, UCSF School of Medicine, San Francisco, CA, USA
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