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Chang DG, Kim JW, Kim HJ, Kim YH, Kim SI, Ha KY. The neuro-protective role of telomerase via TERT/TERF-2 in the acute phase of spinal cord injury. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2023; 32:2431-2440. [PMID: 37165116 DOI: 10.1007/s00586-023-07561-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/04/2023] [Accepted: 01/22/2023] [Indexed: 05/12/2023]
Abstract
PURPOSE To investigate the interaction of telomerase activity and telomere length on neuro-protection or neuro-degeneration effects after spinal cord injury (SCI). METHODS A contusive SCI model was developed using 56 Sprague-Dawley rats. Seven rats were allocated into acute injury phase groups (1, 3, 8, 24, and 48 h), and sub-acute and chronic injury phase groups (1, 2, and 4 weeks). Telomerase activity was assessed by telomerase reverse transcriptase (TERT) and telomeric repeat binding factor-2 (TERF-2). Differentiation of activated neural stem cells was investigated by co-expression of neuronal/glial cell markers. Apoptosis expression was also investigated by caspase-3, 8, and 9 using terminal deoxynucleotidyl transferase dUTP nick end labelling staining. Immunofluorescence staining and western blotting were performed for quantitative analyses. RESULTS Expression of TERT increased gradually until 24 h post-injury, and was decreased following SCI (P < 0.05). TERF-2 also was increased following SCI until 24 h post-injury and then decreased with time (P < 0.05). Co-localization of TERT and TERF-2 was higher at 24 h post-injury. High expression of TERT was seen in neurons (Neu N Ab), however, expression of TERT was relatively lower in astrocytes and oligodendrocytes. Apoptosis analysis showed persistent high expression of caspases-3, -9, and -8 during the observation period. CONCLUSIONS Increased TERT and TERF-2 activity were noted 24 h post-injury in the acute phase of SCI with TERF-2 maintaining telomeric-repeat length. Our results suggest that increased activity of telomere maintenance may be related to neuro-protective mechanisms against subsequent apoptosis resulting from DNA damage after acute SCI.
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Affiliation(s)
- Dong-Gune Chang
- Department of Orthopaedic Surgery, Inje University Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Korea
| | - Jang-Woon Kim
- Department of Orthopaedic Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hong Jin Kim
- Department of Orthopaedic Surgery, Inje University Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Korea
| | - Young-Hoon Kim
- Department of Orthopaedic Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sang-Il Kim
- Department of Orthopaedic Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Kee-Yong Ha
- Department of Orthopaedic Surgery, College of Medicine, Kyung Hee University at Gangdong, Dongnam-ro, Gangdong-Gu, 892, Seoul, Republic of Korea.
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Zhao R, Yang L, He S, Xia T. Nucleus pulposus cell senescence is regulated by substrate stiffness and is alleviated by LOX possibly through the integrin β1-p38 MAPK signaling pathway. Exp Cell Res 2022; 417:113230. [PMID: 35667466 DOI: 10.1016/j.yexcr.2022.113230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 05/01/2022] [Accepted: 05/27/2022] [Indexed: 11/04/2022]
Abstract
Intervertebral disc degeneration (IVDD) is a main contributor to induce low back pain, and the pathogenic mechanism of IVDD remains unclear. The nucleus pulposus (NP) is a component of the intervertebral disc (IVD) that provides protection from mechanical stimuli. The matrix stiffness of NP tissue increases during the process of disc degeneration. Although several studies have found that pathological mechanical stimuli induce NP cell senescence, which is relevant for NP degeneration, however, the effect of matrix stiffness on NP cell senescence is not clear. Therefore, in the present study, we used polyvinyl alcohol (PVA) hydrogel with controllable stiffness to mimic the matrix stiffness of normal (4 kPa) and severely degenerated (20 kPa) NP tissue. Rat NP cells were isolated and cultured on substrates with different stiffness, and the cell proliferation, SA-β-gal activity, cell cycle, telomerase activity and the phenotype markers of NP cells were analyzed. Moreover, cytoskeleton staining and NP cellular Young's modulus on different substrates were also measured. To further investigate how substrate stiffness affects NP cell senescence, lysyl oxidase (LOX) was used to restore the extracellular matrix (ECM) synthesis of NP cells. The expression levels of integrin β1 and p38 MAPK were then measured. Our results showed that the 20 kPa substrate significantly induced NP cell senescence compared to the 4 kPa substrate. NP cells cultured on the 20 kPa substrate failed to maintain the expression of their phenotype markers. Furthermore, the 20 kPa substrate induced an increase of Young's modulus of NP cells, which possibly through up regulating the expressions of integrin β1 and p38 MAPK. These results indicated that the integrin β1-p38 MAPK signaling pathway may participated in substrate stiffness induced senescence of NP cells. LOX significantly increased ECM synthesis and inhibited substrate stiffness induced NP cell senescence, which indicated that matrix mechanics may be essential for maintaining the function of NP cell. Our results may provide a new perspective on the mechanism of IVDD by pathological matrix mechanics.
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Affiliation(s)
- Runze Zhao
- Department of Orthopedic Surgery, The First Affiliated Hospital, Orthopedic Institute, Medical College, Soochow University, Suzhou, 215000, Jiangsu, China
| | - Li Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing, 400044, China
| | - Shuangjian He
- Department of Orthopedics, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, 215153, Jiangsu, China.
| | - Tingting Xia
- Institute of Clinical Medicine Research, The Affiliated Suzhou Science and Technology Town Hospital of Nanjing Medical University, Suzhou, 215153, Jiangsu, China.
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Mechanical Stretch Induces Annulus Fibrosus Cell Senescence through Activation of the RhoA/ROCK Pathway. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5321121. [PMID: 34840974 PMCID: PMC8626192 DOI: 10.1155/2021/5321121] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 01/07/2023]
Abstract
Background Intervertebral disc is responsible for absorbing and transmitting mechanical compression. Under physiological conditions, the peripheral annulus fibrosus (AF) cells are subjected to different magnitudes of transverse mechanical stretch depending on the swelling of the central nucleus pulposus tissue. However, the biological behavior of AF cells under mechanical stretch is not well studied. Objective This study was performed to study the effects of mechanical tension on AF cell senescence and the potential signaling transduction pathway. Methods Rat AF cells were made to experience different magnitudes of mechanical stretch (2% elongation and 20% elongation for 4 hours every day at 1 Hz) in a 10-day experiment period. The inhibitor RKI-1447 of the Rho-associated coiled-coil–containing protein kinases (ROCK) was added along with culture medium to investigate its role. Cell proliferation, cell cycle, telomerase activity, and expression of senescence markers (p16 and p53) were analyzed. Results We found that 20% elongation significantly decreased cell proliferation, promoted G0/G1 cell cycle arrest, decreased telomerase activity, and upregulated mRNA/protein expression of p16 and p53. Moreover, the inhibitor RKI-1447 partly resisted effects of 20% elongation on these parameters of cell senescence. Conclusion High mechanical stretch obviously induces AF cell senescence through the RhoA/ROCK pathway. This study provides us a deeper understanding on the AF cell's behavior under mechanical stretch.
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Kim KW, Jeong SW, Park HY, Heu JY, Jung HY, Lee JS. The effect of prolonged rhBMP-2 treatment on telomerase activity, replicative capacity and senescence of human nucleus pulposus cells. Biotech Histochem 2020; 95:490-498. [PMID: 32037884 DOI: 10.1080/10520295.2020.1721560] [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: 10/25/2022] Open
Abstract
We investigated the effect of prolonged rhBMP-2 treatment on telomerase activity, replicative capacity and senescence of nucleus pulposus cells (NPCs) during long term culture. We obtained intervertebral disc (IVD) tissues with grade III degeneration from four patients. NPCs were isolated and passaged serially in three groups: control group, low-dose rhBMP-2 group and high-dose rhBMP-2 group until the cells reached the end of their replicative lifespan. Cumulative population doubling level (CPDL), telomerase activity and senescence markers, senescence-associated β-galactosidase (SA-β-gal), p53, p21, and p16, were assessed. The replicative capacity of NPCs in the high-dose rhBMP-2 group was decreased significantly compared to the control and low-dose rhBMP-2 groups. Mean telomerase activity was significantly greater in the high-dose rhBMP-2 group compared to the control and low-dose rhBMP-2 groups. The percentage of SA-β-gal-positive NPCs increased more rapidly in the high-dose rhBMP-2 group with passaging compared to the control and low-dose rhBMP-2 groups. The expression of p53, p21, and p16 in both low and high dose rhBMP-2 groups increased in all passages compared to the control group. We found that prolonged high-dose rhBMP-2 treatment increased telomerase activity of human NPCs, but decreased replicative capacity and lifespan in long term culture. We also found that excessive growth stimulation by prolonged high-dose rhBMP-2 treatment can promote NPCs senescence and result in growth arrest.
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Affiliation(s)
- Ki-Won Kim
- Department of Orthopedic Surgery, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul, Korea
| | - Seo-Won Jeong
- Department of Orthopedic Research, Medical Research Institute, Yeouido St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul, Korea
| | - Hyung-Youl Park
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul, Korea
| | - Jun-Young Heu
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul, Korea
| | - Ho-Young Jung
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul, Korea
| | - Jun-Seok Lee
- Department of Orthopedic Surgery, Eunpyeong St. Mary's Hospital, College of Medicine, The Catholic University of Korea , Seoul, Korea
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Nucleus pulposus cell senescence is alleviated by resveratrol through regulating the ROS/NF-κB pathway under high-magnitude compression. Biosci Rep 2018; 38:BSR20180670. [PMID: 29875176 PMCID: PMC6435537 DOI: 10.1042/bsr20180670] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 05/27/2018] [Accepted: 06/06/2018] [Indexed: 12/21/2022] Open
Abstract
Mechanical overloading is a risk factor of disc degeneration. Studies have demonstrated that resveratrol helps to maintain the disc cell’s healthy biology. The present study aims to investigate whether resveratrol can suppress mechanical overloading-induced nucleus pulposus (NP) cell senescence in vitro and the potential mechanism. The isolated rat NP cells were seeded in the decalcified bone matrix (DBM) and cultured under non-compression (control) and compression (20% deformation, 1.0 Hz, 6 h/day) for 5 days using the mechanically active bioreactor. The resveratrol (30 and 60 μM) was added into the culture medium of the compression group to investigate its protective effects against the NP cell senescence. NP cell senescence was evaluated by cell proliferation, cell cycle, senescence-associated β-galactosidase (SA-β-Gal) activity, telomerase (TE) activity, and gene expression of the senescence markers (p16 and p53). Additionally, the reactive oxygen species (ROS) content and activity of the NF-κB pathway were also analyzed. Compared with the non-compression group, the high-magnitude compression significantly promoted NP cell senescence, increased ROS generation and activity of the NF-κB pathway. However, resveratrol partly attenuated NP cell senescence, decreased ROS generation and activity of the NF-κB pathway in a concentration-dependent manner under mechanical compression. Resveratrol can alleviate mechanical overloading-induced NP cell senescence through regulating the ROS/NF-κB pathway. The present study provides that resveratrol may be a potential drug for retarding mechanical overloading-induced NP cell senescence.
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Resveratrol attenuates high glucose-induced nucleus pulposus cell apoptosis and senescence through activating the ROS-mediated PI3K/Akt pathway. Biosci Rep 2018; 38:BSR20171454. [PMID: 29273676 PMCID: PMC5897744 DOI: 10.1042/bsr20171454] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 12/08/2017] [Accepted: 12/18/2017] [Indexed: 12/19/2022] Open
Abstract
Background: Diabetes mellitus is closely correlated with disc degeneration. Nucleus pulposus (NP) cell apoptosis and senescence are typical cellular features within the degenerative disc. Resveratrol is a newly identified phytoalexin that has protective effects on cartilaginous tissue. Objective: To investigate the whether resveratrol can protect against high glucose-induced NP cell apoptosis and senescence, and the potential mechanism in this process. Methods: Rat NP cells were cultured in either 10% FBS culture medium (control group) or 10% FBS with a high glucose concentration (0.2 M, experiment group) for 3 days. Resveratrol or the combination of resveratrol and LY294002 was added into the culture medium of experiment group to investigate the effects of resveratrol and the PI3K/Akt pathway. Results: High glucose significantly promoted NP cell apoptosis and NP cell senescence compared with the control group. Resveratrol exhibited protective effects against high glucose-induced NP cell apoptosis and senescence. Further analysis showed that resveratrol suppressed reactive oxygen species (ROS) generation and increased the activity of the PI3K/Akt pathway under the high glucose condition. However, the LY294002 had no significant effects on ROS content in the resveratrol-treated high glucose group. Conclusion: Resveratrol can attenuate high glucose-induced NP cell apoptosis and senescence, and the activation of ROS-mediated PI3K/Akt pathway may be the potential mechanism in this process.
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The response of nucleus pulposus cell senescence to static and dynamic compressions in a disc organ culture. Biosci Rep 2018; 38:BSR20180064. [PMID: 29437905 PMCID: PMC5843747 DOI: 10.1042/bsr20180064] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 01/27/2018] [Accepted: 01/31/2018] [Indexed: 01/08/2023] Open
Abstract
Mechanical stimuli obviously affect disc nucleus pulposus (NP) biology. Previous studies have indicated that static compression exhibits detrimental effects on disc biology compared with dynamic compression. To study disc NP cell senescence under static compression and dynamic compression in a disc organ culture, porcine discs were cultured and subjected to compression (static compression: 0.4 MPa for 4 h once per day; dynamic compression: 0.4 MPa at a frequency of 1.0 Hz for 4 h once per day) for 7 days using a self-developed mechanically active bioreactor. The non-compressed discs were used as controls. Compared with the dynamic compression, static compression significantly promoted disc NP cell senescence, reflected by the increased senescence-associated β-galactosidase (SA-β-Gal) activity, senescence-associated heterochromatic foci (SAHF) formation and senescence markers expression, and the decreased telomerase (TE) activity and NP matrix biosynthesis. Static compression accelerates disc NP cell senescence compared with the dynamic compression in a disc organ culture. The present study provides that acceleration of NP cell senescence may be involved in previously reported static compression-mediated disc NP degenerative changes.
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Aker L, Ghannam M, Alzuabi MA, Jumah F, Alkhdour SM, Mansour S, Samara A, Cronk K, Massengale J, Holsapple J, Adeeb N, Oskouian RJ, Tubbs RS. Molecular Biology and Interactions in Intervertebral Disc Development, Homeostasis, and Degeneration, with Emphasis on Future Therapies: A Systematic Review. ACTA ACUST UNITED AC 2017. [DOI: 10.26632/ss.3.2017.1.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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The inflammatory cytokine TNF-α promotes the premature senescence of rat nucleus pulposus cells via the PI3K/Akt signaling pathway. Sci Rep 2017; 7:42938. [PMID: 28211497 PMCID: PMC5314336 DOI: 10.1038/srep42938] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 01/18/2017] [Indexed: 12/21/2022] Open
Abstract
Premature senescence of nucleus pulposus (NP) cells and inflammation are two common features of degenerated discs. This study investigated the effects of the inflammatory cytokine TNF-α on the premature senescence of NP cells and the molecular mechanism behind this process. Rat NP cells were cultured with or without different concentrations of TNF-α for 1 and 3 days. The inhibitor LY294002 was used to determine the role of the PI3K/Akt pathway. NP cells that were incubated with TNF-α for 3 days followed by 3 days of recovery in the control medium were used to analyze cellular senescence. Results showed that TNF-α promoted premature senescence of NP cells, as indicated by decreased cell proliferation, decreased telomerase activity, increased SA-β-gal staining, the fraction of cells arrested in the G1 phase of the cell cycle, the attenuated ability to synthesize matrix proteins and the up-regulated expression of the senescence marker p16 and p53. Moreover, a high TNF-α concentration produced greater effects than a low TNF-α concentration on day 3 of the experiment. Further analysis indicated that the inhibition of the PI3K/Akt pathway attenuated the TNF-α-induced premature senescence of NP cells. Additionally, TNF-α-induced NP cell senescence did not recover after TNF-α was withdrawn. In conclusion, TNF-α promotes the premature senescence of NP cells, and activation of the PI3K/Akt pathway is involved in this process.
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Ghannam M, Jumah F, Mansour S, Samara A, Alkhdour S, Alzuabi MA, Aker L, Adeeb N, Massengale J, Oskouian RJ, Tubbs RS. Surgical anatomy, radiological features, and molecular biology of the lumbar intervertebral discs. Clin Anat 2017; 30:251-266. [PMID: 27997062 DOI: 10.1002/ca.22822] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/04/2016] [Indexed: 01/07/2023]
Abstract
The intervertebral disc (IVD) is a joint unique in structure and functions. Lying between adjacent vertebrae, it provides both the primary support and the elasticity required for the spine to move stably. Various aspects of the IVD have long been studied by researchers seeking a better understanding of its dynamics, aging, and subsequent disorders. In this article, we review the surgical anatomy, imaging modalities, and molecular biology of the lumbar IVD. Clin. Anat. 30:251-266, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Malik Ghannam
- An-Najah National University Hospital, Nablus, Palestine
| | - Fareed Jumah
- An-Najah National University Hospital, Nablus, Palestine
| | - Shaden Mansour
- An-Najah National University Hospital, Nablus, Palestine
| | - Amjad Samara
- An-Najah National University Hospital, Nablus, Palestine
| | - Saja Alkhdour
- An-Najah National University Hospital, Nablus, Palestine
| | | | - Loai Aker
- An-Najah National University Hospital, Nablus, Palestine
| | - Nimer Adeeb
- Department of Neurosurgery, Boston Medical Center, Boston University, Massachusetts
| | - Justin Massengale
- Department of Neurosurgery, Boston Medical Center, Boston University, Massachusetts
| | | | - R Shane Tubbs
- Department of Anatomical Sciences, St. George's University, Grenada.,Seattle Science Foundation, Seattle, Washington
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