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Feng C, Liu H, Yang M, Zhang Y, Huang B, Zhou Y. Disc cell senescence in intervertebral disc degeneration: Causes and molecular pathways. Cell Cycle 2016; 15:1674-84. [PMID: 27192096 PMCID: PMC4957599 DOI: 10.1080/15384101.2016.1152433] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The accumulation of senescent disc cells in degenerative intervertebral disc (IVD) suggests the detrimental roles of cell senescence in the pathogenesis of intervertebral disc degeneration (IDD). Disc cell senescence decreased the number of functional cells in IVD. Moreover, the senescent disc cells were supposed to accelerate the process of IDD via their aberrant paracrine effects by which senescent cells cause the senescence of neighboring cells and enhance the matrix catabolism and inflammation in IVD. Thus, anti-senescence has been proposed as a novel therapeutic target for IDD. However, the development of anti-senescence therapy is based on our understanding of the molecular mechanism of disc cell senescence. In this review, we focused on the molecular mechanism of disc cell senescence, including the causes and various molecular pathways. We found that, during the process of IDD, age-related damages together with degenerative external stimuli activated both p53-p21-Rb and p16-Rb pathways to induce disc cell senescence. Meanwhile, disc cell senescence was regulated by multiple signaling pathways, suggesting the complex regulating network of disc cell senescence. To understand the mechanism of disc cell senescence better contributes to developing the anti-senescence-based therapies for IDD.
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Affiliation(s)
- Chencheng Feng
- a Department of Orthopedics , Xinqiao Hospital, Third Military Medical University , Chongqing , People's Republic of China
| | - Huan Liu
- a Department of Orthopedics , Xinqiao Hospital, Third Military Medical University , Chongqing , People's Republic of China
| | - Minghui Yang
- a Department of Orthopedics , Xinqiao Hospital, Third Military Medical University , Chongqing , People's Republic of China
| | - Yang Zhang
- a Department of Orthopedics , Xinqiao Hospital, Third Military Medical University , Chongqing , People's Republic of China
| | - Bo Huang
- a Department of Orthopedics , Xinqiao Hospital, Third Military Medical University , Chongqing , People's Republic of China
| | - Yue Zhou
- a Department of Orthopedics , Xinqiao Hospital, Third Military Medical University , Chongqing , People's Republic of China
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Abstract
Progeroid mouse models display phenotypes in multiple organ systems that suggest premature aging and resemble features of natural aging of both mice and humans. The prospect of a significant increase in the global elderly population within the next decades has led to the emergence of "geroscience," which aims at elucidating the molecular mechanisms involved in aging. Progeroid mouse models are frequently used in geroscience as they provide insight into the molecular mechanisms that are involved in the highly complex process of natural aging. This review provides an overview of the most commonly reported nonneoplastic macroscopic and microscopic pathologic findings in progeroid mouse models (eg, osteoporosis, osteoarthritis, degenerative joint disease, intervertebral disc degeneration, kyphosis, sarcopenia, cutaneous atrophy, wound healing, hair loss, alopecia, lymphoid atrophy, cataract, corneal endothelial dystrophy, retinal degenerative diseases, and vascular remodeling). Furthermore, several shortcomings in pathologic analysis and descriptions of these models are discussed. Progeroid mouse models are valuable models for aging, but thorough knowledge of both the mouse strain background and the progeria-related phenotype is required to guide interpretation and translation of the pathology data.
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Affiliation(s)
- L Harkema
- Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - S A Youssef
- Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - A de Bruin
- Dutch Molecular Pathology Center, Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands Department of Pediatrics, Division of Molecular Genetics, University Medical Center Groningen, Groningen, The Netherlands
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Vermeij WP, Hoeijmakers JHJ, Pothof J. Genome Integrity in Aging: Human Syndromes, Mouse Models, and Therapeutic Options. Annu Rev Pharmacol Toxicol 2015; 56:427-45. [PMID: 26514200 DOI: 10.1146/annurev-pharmtox-010814-124316] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human syndromes and mouse mutants that exhibit accelerated but bona fide aging in multiple organs and tissues have been invaluable for the identification of nine denominators of aging: telomere attrition, genome instability, epigenetic alterations, mitochondrial dysfunction, deregulated nutrient sensing, altered intercellular communication, loss of proteostasis, cellular senescence and adult stem cell exhaustion. However, whether and how these instigators of aging interrelate or whether they have one root cause is currently largely unknown. Rare human progeroid syndromes and corresponding mouse mutants with resolved genetic defects highlight the dominant importance of genome maintenance for aging. A second class of aging-related disorders reveals a cross connection with metabolism. As genome maintenance and metabolism are closely interconnected, they may constitute the main underlying biology of aging. This review focuses on the role of genome stability in aging, its crosstalk with metabolism, and options for nutritional and/or pharmaceutical interventions that delay age-related pathology.
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Affiliation(s)
- Wilbert P Vermeij
- Department of Genetics, Erasmus University Medical Center, Postbus 2040, 3000 CA, Rotterdam, The Netherlands; , ,
| | - Jan H J Hoeijmakers
- Department of Genetics, Erasmus University Medical Center, Postbus 2040, 3000 CA, Rotterdam, The Netherlands; , ,
| | - Joris Pothof
- Department of Genetics, Erasmus University Medical Center, Postbus 2040, 3000 CA, Rotterdam, The Netherlands; , ,
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Manandhar M, Boulware KS, Wood RD. The ERCC1 and ERCC4 (XPF) genes and gene products. Gene 2015; 569:153-61. [PMID: 26074087 DOI: 10.1016/j.gene.2015.06.026] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/01/2015] [Accepted: 06/09/2015] [Indexed: 12/22/2022]
Abstract
The ERCC1 and ERCC4 genes encode the two subunits of the ERCC1-XPF nuclease. This enzyme plays an important role in repair of DNA damage and in maintaining genomic stability. ERCC1-XPF nuclease nicks DNA specifically at junctions between double-stranded and single-stranded DNA, when the single-strand is oriented 5' to 3' away from a junction. ERCC1-XPF is a core component of nucleotide excision repair and also plays a role in interstrand crosslink repair, some pathways of double-strand break repair by homologous recombination and end-joining, as a backup enzyme in base excision repair, and in telomere length regulation. In many of these activities, ERCC1-XPF complex cleaves the 3' tails of DNA intermediates in preparation for further processing. ERCC1-XPF interacts with other proteins including XPA, RPA, SLX4 and TRF2 to perform its functions. Disruption of these interactions or direct targeting of ERCC1-XPF to decrease its DNA repair function might be a useful strategy to increase the sensitivity of cancer cells to some DNA damaging agents. Complete deletion of either ERCC1 or ERCC4 is not compatible with viability in mice or humans. However, mutations in the ERCC1 or ERCC4 genes cause a remarkable array of rare inherited human disorders. These include specific forms of xeroderma pigmentosum, Cockayne syndrome, Fanconi anemia, XFE progeria and cerebro-oculo-facio-skeletal syndrome.
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Affiliation(s)
- Mandira Manandhar
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Karen S Boulware
- The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Richard D Wood
- Department of Epigenetics & Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Smithville, TX 78957, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
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Pohl PHI, Cuperman T, Lozito T, Yurube T, Tuan R, Kang J, Vo N, Rodrigues LMR. Expression of matrix factors in the process of neovascularization of intervertebral disc. COLUNA/COLUMNA 2015. [DOI: 10.1590/s1808-185120151402132735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
<sec><title>OBJECTIVE:</title><p> To investigate the effects of proteins products of endothelial cells (ECs) on the annulus fibrosus (AF) cell metabolism in an in vitro culture.</p></sec><sec><title>METHODS:</title><p>Human AF cells were expanded in monolayer cultures and treated with proteins from the medium of cell line HMEC-1 (Human Microvascular Endothelial Cells) (125µg/ml). After 72h of treatment RNA was isolated from AF cells for analysis of gene expression and the culture medium was collected for protein expression analysis.</p></sec><sec><title>RESULTS:</title><p> The qRT-PCR analysis demonstrated increased gene expression of matrix metalloproteinases (MMPs) in AF cells treated with protein products of endothelial cells compared with cells from control group of AF cells: MMP-1 243.10 times (p<0.05), MMP-2 1.37 time (p<0.05), MMP-3 39.83 times (p<0.05) and MMP-13 5.70 times (p<0.05). In contrast, tissue inhibitors of metalloproteinases (TIMPs) were suppressed; TIMP-2 (0.55 time) (p<0.05) and TIMP-3 (0.60 time) (p<0.05) in the exposed groups. The expression of aggrecan gene (0.83 time) (p<0.05), an important extracellular matrix component, was also reduced. MMP-1 and MMP-3 detection was performed, confirming the results of PCR by Western Blot technique.</p></sec><sec><title>CONCLUSIONS:</title><p> In this study, we observed that the proteins produced by ECs induced the MMPs expression and suppressed the TIMPs as well as the aggrecan in primary cells of the human intervertebral disc, targeting the development of potential treatments for intervertebral disc degeneration and associated discogenic pain.</p></sec>
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Affiliation(s)
| | | | | | | | | | | | - Nam Vo
- University of Pittsburgh, United States
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Abstract
STUDY DESIGN IL-1β (interleukin-1β) can activate human nucleus pulposus cells with or without nuclear factor kappa B (NF-κB) inhibition. We undertook a descriptive and mechanistic investigation of catabolic effects of NF-κB signaling pathway in intervertebral disc degenerative changes. OBJECTIVE To clarify the mediatory role of NF-κB signaling pathway in human intervertebral disc degeneration (IDD). SUMMARY OF BACKGROUND DATA IDD is a major cause of lower back pain, but the molecular mechanism behind this process is poorly understood. NF-κB is a family of transcription factors that play a central role in mediating cellular response to damage, stress, and inflammation. Growing evidence implicates chronic activation of NF-κB in many degenerative diseases, but its role in IDD has not been adequately explored. METHODS Human nucleus pulposus cells in monolayer culture were exposed to IL-1β, which increases matrix-degrading enzyme activity in the nucleus pulposus, with or without NF-κB inhibition by BAY11-7082; ribonucleic acid was isolated for real-time polymerase chain reaction analysis of gene expression, Western blot analysis was performed to detect the changes of protein expression. RESULTS NF-κB specific inhibitor BAY11-7082 significantly inhibited IL-1β-induced NF-κB activation. IL-1β-dependent gene upregulation of matrix metalloproteinase (MMP)-3, MMP-9, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, and ADAMTS-5 was significantly reduced by NF-κB inhibition. The decreased gene expression of aggrecan and type II collagen, induced by IL-1β was also reversed by BAY11-7082. NF-κB inhibition reversed the IL-1β-induced changes of protein expression of MMP-3, MMP-9, MMP-13, ADAMTS-4, ADAMTS-5, aggrecan, and type II collagen. CONCLUSION These findings demonstrate that the NF-κB signaling pathway is a key mediator of IDD and represents a therapeutic target for mitigating disc degenerative diseases. LEVEL OF EVIDENCE N/A.
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Gurkar AU, Niedernhofer LJ. Comparison of mice with accelerated aging caused by distinct mechanisms. Exp Gerontol 2015; 68:43-50. [PMID: 25617508 DOI: 10.1016/j.exger.2015.01.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/17/2015] [Accepted: 01/20/2015] [Indexed: 02/05/2023]
Abstract
Aging is the primary risk factor for numerous chronic, debilitating diseases. These diseases impact quality of life of the elderly and consume a large portion of health care costs. The cost of age-related diseases will only increase as the world's population continues to live longer. Thus it would be advantageous to consider aging itself as a therapeutic target, potentially stemming multiple age-related diseases simultaneously. While logical, this is extremely challenging as the molecular mechanisms that drive aging are still unknown. Furthermore, clinical trials to treat aging are impractical. Even in preclinical models, testing interventions to extend healthspan in old age are lengthy and therefore costly. One approach to expedite aging studies is to take advantage of mouse strains that are engineered to age rapidly. These strains are genetically and phenotypically quite diverse. This review aims to offer a comparison of several of these strains to highlight their relative strengths and weaknesses as models of mammalian and more specifically human aging. Additionally, careful identification of commonalities among the strains may lead to the identification of fundamental pathways of aging.
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Affiliation(s)
- Aditi U Gurkar
- Department of Metabolism and Aging, Scripps Florida, 130 Scripps Way #3B3, Jupiter, FL 33458, USA
| | - Laura J Niedernhofer
- Department of Metabolism and Aging, Scripps Florida, 130 Scripps Way #3B3, Jupiter, FL 33458, USA.
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Cell-autonomous progeroid changes in conditional mouse models for repair endonuclease XPG deficiency. PLoS Genet 2014; 10:e1004686. [PMID: 25299392 PMCID: PMC4191938 DOI: 10.1371/journal.pgen.1004686] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 08/19/2014] [Indexed: 01/15/2023] Open
Abstract
As part of the Nucleotide Excision Repair (NER) process, the endonuclease XPG is involved in repair of helix-distorting DNA lesions, but the protein has also been implicated in several other DNA repair systems, complicating genotype-phenotype relationship in XPG patients. Defects in XPG can cause either the cancer-prone condition xeroderma pigmentosum (XP) alone, or XP combined with the severe neurodevelopmental disorder Cockayne Syndrome (CS), or the infantile lethal cerebro-oculo-facio-skeletal (COFS) syndrome, characterized by dramatic growth failure, progressive neurodevelopmental abnormalities and greatly reduced life expectancy. Here, we present a novel (conditional) Xpg−/− mouse model which -in a C57BL6/FVB F1 hybrid genetic background- displays many progeroid features, including cessation of growth, loss of subcutaneous fat, kyphosis, osteoporosis, retinal photoreceptor loss, liver aging, extensive neurodegeneration, and a short lifespan of 4–5 months. We show that deletion of XPG specifically in the liver reproduces the progeroid features in the liver, yet abolishes the effect on growth or lifespan. In addition, specific XPG deletion in neurons and glia of the forebrain creates a progressive neurodegenerative phenotype that shows many characteristics of human XPG deficiency. Our findings therefore exclude that both the liver as well as the neurological phenotype are a secondary consequence of derailment in other cell types, organs or tissues (e.g. vascular abnormalities) and support a cell-autonomous origin caused by the DNA repair defect itself. In addition they allow the dissection of the complex aging process in tissue- and cell-type-specific components. Moreover, our data highlight the critical importance of genetic background in mouse aging studies, establish the Xpg−/− mouse as a valid model for the severe form of human XPG patients and segmental accelerated aging, and strengthen the link between DNA damage and aging. Accumulation of DNA damage has been implicated in aging. Many premature aging syndromes are due to defective DNA repair systems. The endonuclease XPG is involved in repair of helix-distorting DNA lesions, and XPG defects cause the cancer-prone condition xeroderma pigmentosum (XP) alone or combined with the severe neurodevelopmental progeroid disorder Cockayne syndrome (CS). Here, we present a novel (conditional) Xpg−/− mouse model which -in a C57BL6/FVB F1 hybrid background- displays many progressive progeroid features, including early cessation of growth, cachexia, kyphosis, osteoporosis, neurodegeneration, liver aging, retinal degeneration, and reduced lifespan. In a constitutive mutant with a complex phenotype it is difficult to dissect cause and consequence. We have therefore generated liver- and forebrain-specific Xpg mutants and demonstrate that they exhibit progressive anisokaryosis and neurodegeneration, respectively, indicating that a cell-intrinsic repair defect in neurons can account for neuronal degeneration. These findings strengthen the link between DNA damage and the complex process of aging.
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Markova DZ, Kepler CK, Addya S, Murray HB, Vaccaro AR, Shapiro IM, Anderson DG, Albert TJ, Risbud MV. An organ culture system to model early degenerative changes of the intervertebral disc II: profiling global gene expression changes. Arthritis Res Ther 2014; 15:R121. [PMID: 24171898 PMCID: PMC3978582 DOI: 10.1186/ar4301] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 09/16/2013] [Indexed: 12/15/2022] Open
Abstract
Introduction Despite many advances in our understanding of the molecular basis of disc degeneration, there remains a paucity of preclinical models which can be used to study the biochemical and molecular events that drive disc degeneration, and the effects of potential therapeutic interventions. The goal of this study is to characterize global gene expression changes in a disc organ culture system that mimics early nontraumatic disc degeneration. Methods To mimic a degenerative insult, rat intervertebral discs were cultured in the presence of TNF-α, IL-1β and serum-limiting conditions. Gene expression analysis was performed using a microarray to identify differential gene expression between experimental and control groups. Differential pattern of gene expression was confirmed using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) or Western blot. Results Treatment resulted in significant changes in expression of more than 1,000 genes affecting many aspects of cell function including cellular movement, the cell cycle, cellular development, and cell death and proliferation. Many of the most highly upregulated and downregulated genes have known functions in disc degeneration and extracellular matrix hemostasis. Construction of gene networks based on known cellular pathways and expression data from our analysis demonstrated that the network associated with cell death, cell cycle regulation and DNA replication and repair was most heavily affected in this model of disc degeneration. Conclusions This rat organ culture model uses cytokine exposure to induce wide gene expression changes with the most affected genes having known reported functions in disc degeneration. We propose that this model is a valuable tool to study the etiology of disc degeneration and evaluate potential therapeutic treatments.
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Holguin N, Aguilar R, Harland RA, Bomar BA, Silva MJ. The aging mouse partially models the aging human spine: lumbar and coccygeal disc height, composition, mechanical properties, and Wnt signaling in young and old mice. J Appl Physiol (1985) 2014; 116:1551-60. [PMID: 24790018 PMCID: PMC4064379 DOI: 10.1152/japplphysiol.01322.2013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/30/2014] [Indexed: 01/07/2023] Open
Abstract
Murine lumbar and coccygeal (tail) regions of spines are commonly used to study cellular signaling of age-related disc diseases, but the tissue-level changes of aging intervertebral discs and vertebrae of each spinal region remain unclear. Furthermore, the impact of aging lumbar and coccygeal discs on Wnt/β-catenin signaling, which is putatively involved in the catabolism of intervertebral discs, is also unclear. We compared disc/vertebrae morphology and mechanics and biochemical composition of intervertebral discs from lumbar and coccygeal regions between young (4-5 mo) and old (20-22 mo) female C57BL/6 mice. Center intervertebral disc height from both regions was greater in old discs than young discs. Compared with young, old lumbar discs had a lower early viscous coefficient (a measure of stiffness) by 40%, while conversely old coccygeal discs were stiffer by 53%. Biochemically, old mice had double the collagen content in lumbar and coccygeal discs of young discs, greater glycosaminoglycan in lumbar discs by 37%, but less glycosaminoglycan in coccygeal discs by 32%. Next, we compared Wnt activity of lumbar and coccygeal discs of 4- to 5-mo and 12- to 14-mo TOPGAL mice. Despite the disc-specific changes, aging decreased Wnt signaling in the nucleus pulposus from both spinal regions by ≥64%. Compared with young, trabecular bone volume/tissue volume and ultimate force were less in old lumbar vertebrae, but greater in old coccygeal vertebrae. Thus intervertebral discs and vertebrae age in a spinal region-dependent manner, but these differential age-related changes may be uncoupled from Wnt signaling. Overall, lumbar and coccygeal regions are not interchangeable in modeling human aging.
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Affiliation(s)
- Nilsson Holguin
- Department of Orthopedics, Washington University, St. Louis, Missouri; and
| | - Rhiannon Aguilar
- Department of Orthopedics, Washington University, St. Louis, Missouri; and
| | - Robin A Harland
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Bradley A Bomar
- Department of Orthopedics, Washington University, St. Louis, Missouri; and
| | - Matthew J Silva
- Department of Orthopedics, Washington University, St. Louis, Missouri; and Department of Biomedical Engineering, Washington University, St. Louis, Missouri
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Nasto LA, Ngo K, Leme AS, Robinson AR, Dong Q, Roughley P, Usas A, Sowa GA, Pola E, Kang J, Niedernhofer LJ, Shapiro S, Vo NV. Investigating the role of DNA damage in tobacco smoking-induced spine degeneration. Spine J 2014; 14:416-23. [PMID: 24211096 PMCID: PMC3944725 DOI: 10.1016/j.spinee.2013.08.034] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 07/15/2013] [Accepted: 08/23/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Tobacco smoking is a key risk factor for spine degeneration. However, the underlying mechanism by which smoking induces degeneration is not known. Recent studies implicate DNA damage as a cause of spine and intervertebral disc degeneration. Because tobacco smoke contains many genotoxins, we hypothesized that tobacco smoking promotes spine degeneration by inducing cellular DNA damage. PURPOSE To determine if DNA damage plays a causal role in smoking-induced spine degeneration. STUDY DESIGN To compare the effect of chronic tobacco smoke inhalation on intervertebral disc and vertebral bone in normal and DNA repair-deficient mice to determine the contribution of DNA damage to degenerative changes. METHODS Two-month-old wild-type (C57BL/6) and DNA repair-deficient Ercc1(-/Δ) mice were exposed to tobacco smoke by direct inhalation (4 cigarettes/day, 5 days/week for 7 weeks) to model first-hand smoking in humans. Total disc proteoglycan (PG) content (1,9-dimethylmethylene blue assay), PG synthesis ((35)S-sulfate incorporation assay), aggrecan proteolysis (immunoblotting analysis), and vertebral bone morphology (microcomputed tomography) were measured. RESULTS Exposure of wild-type mice to tobacco smoke led to a 19% increase in vertebral porosity and a 61% decrease in trabecular bone volume. Intervertebral discs of smoke-exposed animals also showed a 2.6-fold decrease in GAG content and an 8.1-fold decrease in new PG synthesis. These smoking-induced degenerative changes were similar but not worse in Ercc1(-/Δ) mice. CONCLUSIONS Short-term exposure to high levels of primary tobacco smoke inhalation promotes degeneration of vertebral bone and discs. Disc degeneration is primarily driven by reduced synthesis of proteoglycans needed for vertebral cushioning. Degeneration was not exacerbated in congenic DNA repair-deficient mice, indicating that DNA damage per se does not have a significant causal role in driving smoke-induced spine degeneration.
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Affiliation(s)
- Luigi A Nasto
- Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Department of Orthopaedic Surgery, Catholic University of Rome School of Medicine, "A. Gemelli" University Hospital, l.go Agostino Gemelli 8, 00168 Roma, Italy
| | - Kevin Ngo
- Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Adriana S Leme
- Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace St, Pittsburgh, PA 15213, USA
| | - Andria R Robinson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Qing Dong
- Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Peter Roughley
- McGill Scoliosis and Spine Group, Genetics Unit, Shriners Hospital for Children, Montreal, Quebec H3G 1A6, Canada
| | - Arvydas Usas
- Department of Orthopaedic Surgery of UPMC, Stem Cell Research Center, Pittsburgh, PA 15261, USA
| | - Gwendolyn A Sowa
- Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Enrico Pola
- Department of Orthopaedic Surgery, Catholic University of Rome School of Medicine, "A. Gemelli" University Hospital, l.go Agostino Gemelli 8, 00168 Roma, Italy
| | - James Kang
- Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Laura J Niedernhofer
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA; Department of Metabolism and Aging, The Scripps Research Institute, 130 Scripps Way #3B3, Jupiter, FL 33458-5284, USA
| | - Steven Shapiro
- Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace St, Pittsburgh, PA 15213, USA
| | - Nam V Vo
- Department of Orthopaedic Surgery, Ferguson Laboratory for Orthopaedic Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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Roh DS, Du Y, Gabriele ML, Robinson AR, Niedernhofer LJ, Funderburgh JL. Age-related dystrophic changes in corneal endothelium from DNA repair-deficient mice. Aging Cell 2013; 12:1122-31. [PMID: 23927039 DOI: 10.1111/acel.12143] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2013] [Indexed: 12/13/2022] Open
Abstract
The corneal endothelium (CE) is a single layer of cells lining the posterior face of the cornea providing metabolic functions essential for maintenance of corneal transparency. Adult CE cells lack regenerative potential, and the number of CE cells decreases throughout life. To determine whether endogenous DNA damage contributes to the age-related spontaneous loss of CE, we characterized CE in Ercc1(-/Δ) mice, which have impaired capacity to repair DNA damage and age prematurely. Eyes from 4.5- to 6-month-old Ercc1(-/Δ) mice, age-matched wild-type (WT) littermates, and old WT mice (24- to 34-month-old) were compared by spectral domain optical coherence tomography and corneal confocal microscopy. Histopathological changes in CE were further identified in paraffin tissue sections, whole-mount immunostaining, and scanning electron and transmission electron microscopy. The CE of old WT mice displayed polymorphism and polymegathism, polyploidy, decreased cell density, increased cell size, increases in Descemet's thickness, and the presence of posterior projections originating from the CE toward the anterior chamber, similar to changes documented for aging human corneas. Similar changes were observed in young adult Ercc1(-/Δ) mice CE, demonstrating spontaneous premature aging of the CE of these DNA repair-deficient mice. CD45(+) immune cells were associated with the posterior surface of CE from Ercc1(-/Δ) mice and the tissue expressed increased IL-1α, Cxcl2, and TNFα, pro-inflammatory proteins associated with senescence-associated secretory phenotype. These data provide strong experimental evidence that DNA damage can promote aging of the CE and that Ercc1(-/Δ) mice offer a rapid and accurate model to study CE pathogenesis and therapy.
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Affiliation(s)
- Danny S. Roh
- Department of Ophthalmology; University of Pittsburgh School of Medicine; 203 Lothrop St. Pittsburgh PA 15213 USA
| | - Yiqin Du
- Department of Ophthalmology; University of Pittsburgh School of Medicine; 203 Lothrop St. Pittsburgh PA 15213 USA
| | - Michelle L. Gabriele
- Department of Ophthalmology; University of Pittsburgh School of Medicine; 203 Lothrop St. Pittsburgh PA 15213 USA
| | - Andria R. Robinson
- Department of Human Genetics; University of Pittsburgh School of Public Health; 130 DeSoto Street Pittsburgh PA 15261 USA
- University of Pittsburgh Cancer Institute; Hillman Cancer Center; 5117 Centre Ave, 2.6 Pittsburgh PA 15213 USA
| | - Laura J. Niedernhofer
- University of Pittsburgh Cancer Institute; Hillman Cancer Center; 5117 Centre Ave, 2.6 Pittsburgh PA 15213 USA
- Department of Microbiology and Molecular Genetics; University of Pittsburgh School of Medicine; 523 Bridgeside Point II 450 Technology Drive Pittsburgh PA 15219 USA
| | - James L. Funderburgh
- Department of Ophthalmology; University of Pittsburgh School of Medicine; 203 Lothrop St. Pittsburgh PA 15213 USA
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Nidadavolu LS, Niedernhofer LJ, Khan SA. Identification of microRNAs dysregulated in cellular senescence driven by endogenous genotoxic stress. Aging (Albany NY) 2013; 5:460-73. [PMID: 23852002 PMCID: PMC3824412 DOI: 10.18632/aging.100571] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
XFE progeroid syndrome, a disease of accelerated aging caused by deficiency in the DNA repair endonuclease XPF-ERCC1, is modeled by Ercc1 knockout and hypomorphic mice. Tissues and primary cells from these mice senesce prematurely, offering a unique opportunity to identify factors that regulate senescence and aging. We compared microRNA (miRNA) expression in Ercc1−/− primary mouse embryonic fibroblasts (MEFs) and wild-type (WT) MEFs in different growth conditions to identify miRNAs that drive cellular senescence. Microarray analysis showed three differentially expressed miRNAs in passage 7 (P7) Ercc1−/− MEFs grown at 20% O2 compared to Ercc1−/− MEFs grown at 3% O2. Thirty-six differentially expressed miRNAs were identified in Ercc1−/− MEFs at P7 compared to early passage (P3) in 3% O2. Eight of these miRNAs (miR-449a, miR-455*, miR-128, miR-497, miR-543, miR-450b-3p, miR-872 and miR-10b) were similarly downregulated in the liver of progeroid Ercc1−/Δ and old WT mice compared to adult WT mice, a tissue that senesces with aging. Three miRNAs (miR-449a, miR-455* and miR-128) were also downregulated in Ercc1−/Δ and WT old mice kidneys compared to young WT mice. We also discovered that the miRNA expression regulator Dicer is significantly downregulated in tissues of old mice and late passage cells compared to young controls. Collectively these results support the conclusion that the miRNAs identified may play an important role in staving off cellular senescence and their altered expression could be indicative of aging.
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Affiliation(s)
- Lolita S Nidadavolu
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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Nasto LA, Robinson AR, Ngo K, Clauson CL, Dong Q, St. Croix C, Sowa G, Pola E, Robbins PD, Kang J, Niedernhofer LJ, Wipf P, Vo NV. Mitochondrial-derived reactive oxygen species (ROS) play a causal role in aging-related intervertebral disc degeneration. J Orthop Res 2013; 31:1150-7. [PMID: 23389888 PMCID: PMC3668354 DOI: 10.1002/jor.22320] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 01/05/2013] [Indexed: 02/04/2023]
Abstract
Oxidative damage is a well-established driver of aging. Evidence of oxidative stress exists in aged and degenerated discs, but it is unclear how it affects disc metabolism. In this study, we first determined whether oxidative stress negatively impacts disc matrix metabolism using disc organotypic and cell cultures. Mouse disc organotypic culture grown at atmospheric oxygen (20% O(2)) exhibited perturbed disc matrix homeostasis, including reduced proteoglycan synthesis and enhanced expression of matrix metalloproteinases, compared to discs grown at low oxygen levels (5% O(2)). Human disc cells grown at 20% O(2) showed increased levels of mitochondrial-derived superoxide anions and perturbed matrix homeostasis. Treatment of disc cells with the mitochondria-targeted reactive oxygen species (ROS) scavenger XJB-5-131 blunted the adverse effects caused by 20% O(2). Importantly, we demonstrated that treatment of accelerated aging Ercc1(-/Δ) mice, previously established to be a useful in vivo model to study age-related intervertebral disc degeneration (IDD), also resulted in improved disc total glycosaminoglycan content and proteoglycan synthesis. This demonstrates that mitochondrial-derived ROS contributes to age-associated IDD in Ercc1(-/Δ) mice. Collectively, these data provide strong experimental evidence that mitochondrial-derived ROS play a causal role in driving changes linked to aging-related IDD and a potentially important role for radical scavengers in preventing IDD.
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Affiliation(s)
- Luigi A. Nasto
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Orthopaedic Surgery, Catholic University of Rome School of Medicine, “A. Gemelli” University Hospital, l.go Agostino Gemelli 8, 00168 Roma, Italy
| | - Andria R. Robinson
- Department of Human Genetics, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15261, USA
- University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA
| | - Kevin Ngo
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Cheryl L. Clauson
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Qing Dong
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Claudette St. Croix
- Center for Biologic Imaging, Environmental and Occupational Health, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Gwendolyn Sowa
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Enrico Pola
- Department of Orthopaedic Surgery, Catholic University of Rome School of Medicine, “A. Gemelli” University Hospital, l.go Agostino Gemelli 8, 00168 Roma, Italy
| | - Paul D. Robbins
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - James Kang
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Laura J. Niedernhofer
- University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213, USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Peter Wipf
- Department of Chemistry and Center for Chemical Methodologies and Library Development, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Nam V. Vo
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Vo N, Niedernhofer LJ, Nasto LA, Jacobs L, Robbins PD, Kang J, Evans CH. An overview of underlying causes and animal models for the study of age-related degenerative disorders of the spine and synovial joints. J Orthop Res 2013; 31:831-7. [PMID: 23483579 PMCID: PMC3628921 DOI: 10.1002/jor.22204] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2011] [Accepted: 07/10/2012] [Indexed: 02/04/2023]
Abstract
As human lifespan increases so does the incidence of age-associated degenerative joint diseases, resulting in significant negative socioeconomic consequences. Osteoarthritis (OA) and intervertebral disc degeneration (IDD) are the most common underlying causes of joint-related chronic disability and debilitating pain in the elderly. Current treatment methods are generally not effective and involve either symptomatic relief with non-steroidal anti-inflammatory drugs and physical therapy or surgery when conservative treatments fail. The limitation in treatment options is due to our incomplete knowledge of the molecular mechanism of degeneration of articular cartilage and disc tissue. Basic understanding of the age-related changes in joint tissue is thus needed to combat the adverse effects of aging on joint health. Aging is caused at least in part by time-dependent accumulation of damaged organelles and macromolecules, leading to cell death and senescence and the eventual loss of multipotent stem cells and tissue regenerative capacity. Studies over the past decades have uncovered a number of important molecular and cellular changes in joint tissues with age. However, the precise causes of damage, cellular targets of damage, and cellular responses to damage remain poorly understood. The objectives of this review are to provide an overview of the current knowledge about the sources of endogenous and exogenous damaging agents and how they contribute to age-dependent degenerative joint disease, and highlight animal models of accelerated aging that could potentially be useful for identifying causes of and therapies for degenerative joint diseases.
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Affiliation(s)
- Nam Vo
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA,Ferguson Laboratory for Orthopaedic Research, 523 Bridgeside Point II. 450 Technology Drive, Pittsburgh, PA 15219
| | - Laura J. Niedernhofer
- Department of Microbiology and Molecular Genetics, 523 Bridgeside Point II. 450 Technology Drive, Pittsburgh, PA 15219,University of Pittsburgh Cancer Institute, Hillman Cancer Center, 5117 Centre Avenue, Pittsburgh, PA 15213-1863, U.S.A
| | - Luigi Aurelio Nasto
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA,Ferguson Laboratory for Orthopaedic Research, 523 Bridgeside Point II. 450 Technology Drive, Pittsburgh, PA 15219
| | - Lloydine Jacobs
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA,Ferguson Laboratory for Orthopaedic Research, 523 Bridgeside Point II. 450 Technology Drive, Pittsburgh, PA 15219
| | - Paul D. Robbins
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA,Department of Microbiology and Molecular Genetics, 523 Bridgeside Point II. 450 Technology Drive, Pittsburgh, PA 15219,University of Pittsburgh Cancer Institute, Hillman Cancer Center, 5117 Centre Avenue, Pittsburgh, PA 15213-1863, U.S.A
| | - James Kang
- Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA,Ferguson Laboratory for Orthopaedic Research, 523 Bridgeside Point II. 450 Technology Drive, Pittsburgh, PA 15219
| | - Christopher H. Evans
- Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, RN-115, Boston, MA 02215, USA
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Cho J, Kook S, Robinson AR, Niedernhofer LJ, Lee BC. Cell autonomous and nonautonomous mechanisms drive hematopoietic stem/progenitor cell loss in the absence of DNA repair. Stem Cells 2013; 31:511-25. [PMID: 23097336 PMCID: PMC3582850 DOI: 10.1002/stem.1261] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 09/23/2012] [Indexed: 12/24/2022]
Abstract
Daily, cells incur tens of thousands of DNA lesions caused by endogenous processes. Due to their long-lived nature, adult stem cells may be particularly susceptible to the negative impact of this constant genotoxic stress. Indeed, in murine models of DNA repair deficiencies, there is accumulation of DNA damage in hematopoietic stem cells and premature loss of function. Herein, we demonstrate that mice expressing reduced levels of ERCC1-XPF DNA repair endonuclease (Ercc1-/Δ mice) spontaneously display a progressive decline in the number and function of hematopoietic stem/progenitor cells (HSPCs). This was accompanied by increased cell death, expression of senescence markers, reactive oxygen species, and DNA damage in HSPC populations, illustrating cell autonomous mechanisms that contribute to loss of function. In addition, the bone marrow microenvironment of Ercc1-/Δ mice was not permissive for the engraftment of transplanted normal stem cells. Bones from Ercc1-/Δ mice displayed excessive osteoclastic activity, which alters the microenvironment in a way that is unfavorable to HSPC maintenance. This was accompanied by increased proinflammatory cytokines in the bone marrow of Ercc1-/Δ mice. These data provide novel evidence that spontaneous, endogenous DNA damage, if not repaired, promotes progressive attrition of adult stem cells via both cell autonomous and nonautonomous mechanisms.
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Affiliation(s)
- JoonSeok Cho
- University of Pittsburgh Cancer Institute, 5117 Centre Ave, Hillman Cancer Center, Pittsburgh, PA 15213 USA
- Department of Medicine, University of Pittsburgh, 1218 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA, 15216
| | - SungHo Kook
- University of Pittsburgh Cancer Institute, 5117 Centre Ave, Hillman Cancer Center, Pittsburgh, PA 15213 USA
- Department of Medicine, University of Pittsburgh, 1218 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA, 15216
| | - Andria Rasile Robinson
- University of Pittsburgh Cancer Institute, 5117 Centre Ave, Hillman Cancer Center, Pittsburgh, PA 15213 USA
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, 130 DeSoto Street, Pittsburgh, PA 15261 USA
| | - Laura J. Niedernhofer
- University of Pittsburgh Cancer Institute, 5117 Centre Ave, Hillman Cancer Center, Pittsburgh, PA 15213 USA
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, 523 Bridgeside Point II, 450 Technology Drive, Pittsburgh, PA 15219 USA
| | - Byeong-Chel Lee
- University of Pittsburgh Cancer Institute, 5117 Centre Ave, Hillman Cancer Center, Pittsburgh, PA 15213 USA
- Department of Medicine, University of Pittsburgh, 1218 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA, 15216
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Cárdenes N, Cáceres E, Romagnoli M, Rojas M. Mesenchymal stem cells: a promising therapy for the acute respiratory distress syndrome. Respiration 2013; 85:267-78. [PMID: 23428562 DOI: 10.1159/000347072] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a pulmonary syndrome with growing prevalence and high mortality and morbidity that increase with age. There is no current therapy able to restore pulmonary function in ARDS patients. Preclinical models of ARDS have demonstrated that intratracheal or systemic administration of mesenchymal stem cells (MSCs) protects the lung against injury. The mechanisms responsible for the protective effects are multiple, including the secretion of multiple paracrine factors capable of modulating the immune response and restoring epithelial and endothelial integrity. Recent studies have demonstrated that MSCs can also control oxidative stress, transfer functional mitochondria to the damaged cells, and control bacterial infection by secretion of antibacterial peptides. These characteristics make MSCs promising candidates for ARDS therapy.
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Affiliation(s)
- Nayra Cárdenes
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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Nasto LA, Wang D, Robinson AR, Clauson CL, Ngo K, Dong Q, Roughley P, Epperly M, Huq SM, Pola E, Sowa G, Robbins PD, Kang J, Niedernhofer LJ, Vo NV. Genotoxic stress accelerates age-associated degenerative changes in intervertebral discs. Mech Ageing Dev 2012; 134:35-42. [PMID: 23262094 DOI: 10.1016/j.mad.2012.11.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Revised: 11/19/2012] [Accepted: 11/24/2012] [Indexed: 01/09/2023]
Abstract
Intervertebral disc degeneration (IDD) is the leading cause of debilitating spinal disorders such as chronic lower back pain. Aging is the greatest risk factor for IDD. Previously, we demonstrated IDD in a murine model of a progeroid syndrome caused by reduced expression of a key DNA repair enzyme. This led us to hypothesize that DNA damage promotes IDD. To test our hypothesis, we chronically exposed adult wild-type (Wt) and DNA repair-deficient Ercc1(-/Δ) mice to the cancer therapeutic agent mechlorethamine (MEC) or ionization radiation (IR) to induce DNA damage and measured the impact on disc structure. Proteoglycan, a major structural matrix constituent of the disc, was reduced 3-5× in the discs of MEC- and IR-exposed animals compared to untreated controls. Expression of the protease ADAMTS4 and aggrecan proteolytic fragments was significantly increased. Additionally, new PG synthesis was reduced 2-3× in MEC- and IR-treated discs compared to untreated controls. Both cellular senescence and apoptosis were increased in discs of treated animals. The effects were more severe in the DNA repair-deficient Ercc1(-/Δ) mice than in Wt littermates. Local irradiation of the vertebra in Wt mice elicited a similar reduction in PG. These data demonstrate that genotoxic stress drives degenerative changes associated with IDD.
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Affiliation(s)
- Luigi A Nasto
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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ISSLS prize winner: inhibition of NF-κB activity ameliorates age-associated disc degeneration in a mouse model of accelerated aging. Spine (Phila Pa 1976) 2012; 37:1819-25. [PMID: 22343279 PMCID: PMC3395770 DOI: 10.1097/brs.0b013e31824ee8f7] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN NF-κB activity was pharmacologically and genetically blocked in an accelerated aging mouse model to mitigate age-related disc degenerative changes. OBJECTIVE To study the mediatory role of NF-κB-signaling pathway in age-dependent intervertebral disc degeneration. SUMMARY OF BACKGROUND DATA Aging is a major contributor to intervertebral disc degeneration (IDD), but the molecular mechanism behind this process is poorly understood. NF-κB is a family of transcription factors that play a central role in mediating cellular response to damage, stress, and inflammation. Growing evidence implicates chronic NF-κB activation as a culprit in many aging-related diseases, but its role in aging-related IDD has not been adequately explored. We studied the effects of NF-κB inhibition on IDD, using a DNA repair-deficient mouse model of accelerated aging (Ercc1 mice) previously been reported to exhibit age-related IDD. METHODS Systemic inhibition of NF-κB activation was achieved either genetically by deletion of 1 allele of the NF-κB subunit p65 (Ercc1p65 mice) or pharmacologically by chronic intraperitoneal administration of the Nemo Binding Domain (8K-NBD) peptide to block the formation of the upstream activator of NF-κB, IκB Inducible Kinase (IKK), in Ercc1 mice. Disc cellularity, total proteoglycan content and proteoglycan synthesis of treated mice, and untreated controls were assessed. RESULTS.: Decreased disc matrix proteoglycan content, a hallmark feature of IDD, and elevated disc NF-κB activity were observed in discs of progeroid Ercc1 mice and naturally aged wild-type mice compared with young wild-type mice. Systemic inhibition of NF-κB by the 8K-NBD peptide in Ercc1 mice increased disc proteoglycan synthesis and ameriolated loss of disc cellularity and matrix proteoglycan. These results were confirmed genetically by using the p65 haploinsufficient Ercc1p65 mice. CONCLUSION These findings demonstrate that the IKK/NF-κB signaling pathway is a key mediator of age-dependent IDD and represents a therapeutic target for mitigating disc degenerative diseases associated with aging.
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Wang D, Nasto LA, Roughley P, Leme AS, Houghton M, Usas A, Sowa G, Lee J, Niedernhofer L, Shapiro S, Kang J, Vo N. Spine degeneration in a murine model of chronic human tobacco smokers. Osteoarthritis Cartilage 2012; 20:896-905. [PMID: 22531458 PMCID: PMC3389285 DOI: 10.1016/j.joca.2012.04.010] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 03/28/2012] [Accepted: 04/13/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate the mechanisms by which chronic tobacco smoking promotes intervertebral disc degeneration (IDD) and vertebral degeneration in mice. METHODS Three month old C57BL/6 mice were exposed to tobacco smoke by direct inhalation (4 cigarettes/day, 5 days/week for 6 months) to model long-term smoking in humans. Total disc proteoglycan (PG) content [1,9-dimethylmethylene blue (DMMB) assay], aggrecan proteolysis (immunobloting analysis), and cellular senescence (p16INK4a immunohistochemistry) were analyzed. PG and collagen syntheses ((35)S-sulfate and (3)H-proline incorporation, respectively) were measured using disc organotypic culture. Vertebral osteoporosity was measured by micro-computed tomography. RESULTS Disc PG content of smoke-exposed mice was 63% of unexposed control, while new PG and collagen syntheses were 59% and 41% of those of untreated mice, respectively. Exposure to tobacco smoke dramatically increased metalloproteinase-mediated proteolysis of disc aggrecan within its interglobular domain (IGD). Cellular senescence was elevated two-fold in discs of smoke-exposed mice. Smoke exposure increased vertebral endplate porosity, which closely correlates with IDD in humans. CONCLUSIONS These findings further support tobacco smoke as a contributor to spinal degeneration. Furthermore, the data provide a novel mechanistic insight, indicating that smoking-induced IDD is a result of both reduced PG synthesis and increased degradation of a key disc extracellular matrix protein, aggrecan. Cleavage of aggrecan IGD is extremely detrimental as this results in the loss of the entire glycosaminoglycan-attachment region of aggrecan, which is vital for attracting water necessary to counteract compressive forces. Our results suggest identification and inhibition of specific metalloproteinases responsible for smoke-induced aggrecanolysis as a potential therapeutic strategy to treat IDD.
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Affiliation(s)
- Dong Wang
- Beijing Haidian Hospital, Department of Orthopaedics. 29 Zhong-Guan-Cun Street, Beijing 100080, China
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
| | - Luigi A Nasto
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
- Department of Orthopaedic Surgery, Catholic University of Rome School of Medicine, “A. Gemelli” University Hospital, l.go Agostino Gemelli 8, 00168 Roma, Italy
| | - Peter Roughley
- Genetics Unit, Shriners Hospital for Children, Montreal, Quebec, Canada
| | - Adriana S. Leme
- University of Pittsburgh School of Medicine, Pittsburgh PA 15213
| | - McGarry Houghton
- University of Pittsburgh School of Medicine, Pittsburgh PA 15213
| | - Arvydas Usas
- Stem Cell Research Center, Department of Orthopaedic Surgery of UPMC, Pittsburgh PA 15261
| | - Gwendolyn Sowa
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
| | - Joon Lee
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
| | - Laura Niedernhofer
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
| | - Steven Shapiro
- University of Pittsburgh School of Medicine, Pittsburgh PA 15213
| | - James Kang
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
| | - Nam Vo
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh PA 15261
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Tilstra JS, Robinson AR, Wang J, Gregg SQ, Clauson CL, Reay DP, Nasto LA, St Croix CM, Usas A, Vo N, Huard J, Clemens PR, Stolz DB, Guttridge DC, Watkins SC, Garinis GA, Wang Y, Niedernhofer LJ, Robbins PD. NF-κB inhibition delays DNA damage-induced senescence and aging in mice. J Clin Invest 2012; 122:2601-12. [PMID: 22706308 DOI: 10.1172/jci45785] [Citation(s) in RCA: 321] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 05/10/2012] [Indexed: 12/21/2022] Open
Abstract
The accumulation of cellular damage, including DNA damage, is thought to contribute to aging-related degenerative changes, but how damage drives aging is unknown. XFE progeroid syndrome is a disease of accelerated aging caused by a defect in DNA repair. NF-κB, a transcription factor activated by cellular damage and stress, has increased activity with aging and aging-related chronic diseases. To determine whether NF-κB drives aging in response to the accumulation of spontaneous, endogenous DNA damage, we measured the activation of NF-κB in WT and progeroid model mice. As both WT and progeroid mice aged, NF-κB was activated stochastically in a variety of cell types. Genetic depletion of one allele of the p65 subunit of NF-κB or treatment with a pharmacological inhibitor of the NF-κB-activating kinase, IKK, delayed the age-related symptoms and pathologies of progeroid mice. Additionally, inhibition of NF-κB reduced oxidative DNA damage and stress and delayed cellular senescence. These results indicate that the mechanism by which DNA damage drives aging is due in part to NF-κB activation. IKK/NF-κB inhibitors are sufficient to attenuate this damage and could provide clinical benefit for degenerative changes associated with accelerated aging disorders and normal aging.
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Affiliation(s)
- Jeremy S Tilstra
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Rowas SA, Haddad R, Gawri R, Al Ma'awi AA, Chalifour LE, Antoniou J, Mwale F. Effect of in utero exposure to diethylstilbestrol on lumbar and femoral bone, articular cartilage, and the intervertebral disc in male and female adult mice progeny with and without swimming exercise. Arthritis Res Ther 2012; 14:R17. [PMID: 22269139 PMCID: PMC3392807 DOI: 10.1186/ar3696] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 01/23/2012] [Indexed: 11/29/2022] Open
Abstract
Introduction Developmental exposure to estrogens has been shown to affect the musculoskeletal system. Furthermore, recent studies have shown that environmental exposure to estrogen-like compounds is much higher than originally anticipated. The aim of this study was to determine the effects of diethylstilbestrol (DES), a well-known estrogen agonist, on articular cartilage, intervertebral disc (IVD), and bone phenotype. Methods C57Bl/6 pregnant mice were dosed orally with vehicle (peanut oil) or 0.1, 1.0, and 10 μg/kg/day of DES on gestational days 11 to 14. Male and female pups were allowed to mature without further treatment until 3 months of age, when swim and sedentary groups were formed. After euthanasia, bone mineral density (BMD), bone mineral content (BMC), bone area (BA), and trabecular bone area (TBA) of the lumbar vertebrae and femur were measured by using a PIXImus Bone Densitometer System. Intervertebral disc proteoglycan was measured with the DMMB assay. Histologic analysis of proteoglycan for IVD and articular cartilage was performed with safranin O staining, and degeneration parameters were scored. Results The lumbar BMC was significantly increased in female swimmers at both the highest and lowest dose of DES, whereas the femoral BMC was increased only at the highest. The males, conversely, showed a decreased BMC at the highest dose of DES for both lumbar and femoral bone. The female swim group had an increased BA at the highest dose of DES, whereas the male counterpart showed a decreased BA for femoral bone. The TBA showed a similar pattern. Proteoglycan analysis of lumbar IVDs showed a decrease at the lowest doses but a significant increase at the highest doses for both males and females. Histologic examination showed morphologic changes of the IVD and articular cartilage for all doses of DES. Conclusions DES significantly affected the musculoskeletal system of adult mice. Results suggest that environmental estrogen contaminants can have a detrimental effect on the developmental lumbar bone growth and mineralization in mice. Further studies measuring the impact of environmental estrogen mimics, such as bisphenol A, are then warranted.
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Affiliation(s)
- Sora Al Rowas
- Lady Davis Institute for Medical Research, Sir Mortimer B, Davis-Jewish General Hospital, 3755 Chemin Cote Ste Catherine, Montréal, Quebec H3T 1E2, Canada
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Muscle-derived stem/progenitor cell dysfunction limits healthspan and lifespan in a murine progeria model. Nat Commun 2012; 3:608. [PMID: 22215083 PMCID: PMC3272577 DOI: 10.1038/ncomms1611] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 11/24/2011] [Indexed: 01/04/2023] Open
Abstract
With ageing, there is a loss of adult stem cell function. However, there is no direct evidence that this has a causal role in ageing-related decline. We tested this using muscle-derived stem/progenitor cells (MDSPCs) in a murine progeria model. Here we show that MDSPCs from old and progeroid mice are defective in proliferation and multilineage differentiation. Intraperitoneal administration of MDSPCs, isolated from young wild-type mice, to progeroid mice confer significant lifespan and healthspan extension. The transplanted MDSPCs improve degenerative changes and vascularization in tissues where donor cells are not detected, suggesting that their therapeutic effect may be mediated by secreted factor(s). Indeed, young wild-type-MDSPCs rescue proliferation and differentiation defects of aged MDSPCs when co-cultured. These results establish that adult stem/progenitor cell dysfunction contributes to ageing-related degeneration and suggests a therapeutic potential of post-natal stem cells to extend health. The function of adult stem cells is diminished with age but the role this dysfunction plays in the aging process is unknown. Here, the injection of muscle-derived stem/progenitor cells from young mice rescues symptoms in progeroid mice and is shown to regenerate tissues independent of engraftment.
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Vo N, Wang D, Sowa G, Witt W, Ngo K, Coelho P, Bedison R, Byer B, Studer R, Lee J, Di YP, Kang J. Differential effects of nicotine and tobacco smoke condensate on human annulus fibrosus cell metabolism. J Orthop Res 2011; 29:1585-91. [PMID: 21448984 DOI: 10.1002/jor.21417] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 02/28/2011] [Indexed: 02/04/2023]
Abstract
Tobacco smoking increases the risk of intervertebral disc degeneration (IDD) and back pain, but the mechanisms underlying the adverse effects of smoking are largely unknown. Current hypotheses predict that smoking contributes to IDD indirectly through nicotine-mediated vasoconstriction which limits the exchange of nutrients between the discs and their surroundings. We alternatively hypothesize that direct contact of disc cells, that is, cells in the outermost annulus and those present along fissures in degenerating discs, with the vascular system containing soluble tobacco smoking constituents could perturb normal metabolic activities resulting in IDD. In this study, we tested our hypothesis by comparing the effects of direct exposure of human disc cells to tobacco smoke condensate and nicotine on cell viability and metabolic activity. We showed that smoke condensate, which contains all of the water-soluble compounds inhaled by smokers, exerts greater detrimental effects on human disc cell viability and metabolism than nicotine. Smoke condensate greatly induced an inflammatory response and gene expression of metalloproteinases while reduced active matrix synthesis and expression of matrix structural genes. Therefore, we have demonstrated that disc cell exposure to the constituents of tobacco smoke has negative consequences which have the potential to alter disc matrix homeostasis.
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Affiliation(s)
- Nam Vo
- Ferguson Laboratory for Orthopaedic Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
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75
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Dollé MET, Kuiper RV, Roodbergen M, Robinson J, de Vlugt S, Wijnhoven SWP, Beems RB, de la Fonteyne L, de With P, van der Pluijm I, Niedernhofer LJ, Hasty P, Vijg J, Hoeijmakers JHJ, van Steeg H. Broad segmental progeroid changes in short-lived Ercc1(-/Δ7) mice. PATHOBIOLOGY OF AGING & AGE RELATED DISEASES 2011; 1:PBA-1-7219. [PMID: 22953029 PMCID: PMC3417667 DOI: 10.3402/pba.v1i0.7219] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 05/17/2011] [Accepted: 05/17/2011] [Indexed: 11/14/2022]
Abstract
Genome maintenance is considered a prime longevity assurance mechanism as apparent from many progeroid human syndromes that are caused by genome maintenance defects. The ERCC1 protein is involved in three genome maintenance systems: nucleotide excision repair, interstrand cross-link repair, and homologous recombination. Here we describe in-life and post-mortem observations for a hypomorphic Ercc1 variant, Ercc1(-/Δ7), which is hemizygous for a single truncated Ercc1 allele, encoding a protein lacking the last seven amino acids. Ercc1(-/Δ7) mice were much smaller and median life span was markedly reduced compared to wild-type siblings: 20 and 118 weeks, respectively. Multiple signs and symptoms of aging were found to occur at an accelerated rate in the Ercc1(-/Δ7) mice as compared to wild-type controls, including a decline in weight of both whole body and various organs, numerous histopathological lesions, and immune parameters. Together they define a segmental progeroid phenotype of the Ercc1(-/Δ7) mouse model.
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Affiliation(s)
- Martijn E T Dollé
- Laboratory of Heath Protection Research, National Institute of Public Health and the Environment, Bilthoven, The Netherlands
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76
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Gregg SQ, Robinson AR, Niedernhofer LJ. Physiological consequences of defects in ERCC1-XPF DNA repair endonuclease. DNA Repair (Amst) 2011; 10:781-91. [PMID: 21612988 DOI: 10.1016/j.dnarep.2011.04.026] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
ERCC1-XPF is a structure-specific endonuclease required for nucleotide excision repair, interstrand crosslink repair, and the repair of some double-strand breaks. Mutations in ERCC1 or XPF cause xeroderma pigmentosum, XFE progeroid syndrome or cerebro-oculo-facio-skeletal syndrome, characterized by increased risk of cancer, accelerated aging and severe developmental abnormalities, respectively. This review provides a comprehensive overview of the health impact of ERCC1-XPF deficiency, based on these rare diseases and mouse models of them. This offers an understanding of the tremendous health impact of DNA damage derived from environmental and endogenous sources.
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Affiliation(s)
- Siobhán Q Gregg
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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77
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Smith JR, Rosenbaum JT, Williams KA. Experimental melanin-induced uveitis: experimental model of human acute anterior uveitis. Ophthalmic Res 2008; 40:136-40. [PMID: 18421227 DOI: 10.1159/000119864] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Experimental melanin-protein-induced uveitis (EMIU), which is also known as experimental autoimmune anterior uveitis, was first described in 1993 by Broekhuyse et al. This experimental uveitis may be induced in certain inbred and outbred rat strains by immunization with bovine ocular melanin. The inflammation shares clinical features with human acute anterior uveitis. The duration of the first episode is approximately 1 month. Spontaneous recovery to a near normal clinical state is the rule, but multiple recurrences are common. Slit-lamp biomicroscopic examination reveals a florid anterior-chamber reaction, with formation of a retro-iridal empyema, fibrin clots and posterior synechiae. At a microscopic level, leukocytic infiltration is first observed in the anterior uvea. Although this tissue remains the site of maximum inflammation throughout an attack, in severe cases, limbitis, vitritis and choroiditis are also observed. Abrogation of EMIU occurs after treatment with anti-CD4 antibody, indicating that the uveitis is controlled by CD4-positive T cells. Several research groups have used EMIU to investigate various aspects of the pathogenesis of acute anterior uveal inflammation, including the participation of different leukocyte subsets, the expression of cell adhesion molecules, cytokines, chemokines and nitric oxide, the role of complement and the impact of apoptosis. In addition, EMIU has also been used to evaluate various biologic interventions with potential implications for the treatment of human disease.
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Affiliation(s)
- Justine R Smith
- Department of Cell and Developmental Biology, Casey Eye Institute, Oregon Health and Science University, Portland, OR 97239, USA.
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