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Song C, Hu P, Peng R, Li F, Fang Z, Xu Y. Bioenergetic dysfunction in the pathogenesis of intervertebral disc degeneration. Pharmacol Res 2024; 202:107119. [PMID: 38417775 DOI: 10.1016/j.phrs.2024.107119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/16/2024] [Accepted: 02/24/2024] [Indexed: 03/01/2024]
Abstract
Intervertebral disc (IVD) degeneration is a frequent cause of low back pain and is the most common cause of disability. Treatments for symptomatic IVD degeneration, including conservative treatments such as analgesics, physical therapy, anti-inflammatories and surgeries, are aimed at alleviating neurological symptoms. However, there are no effective treatments to prevent or delay IVD degeneration. Previous studies have identified risk factors for IVD degeneration such as aging, inflammation, genetic factors, mechanical overload, nutrient deprivation and smoking, but metabolic dysfunction has not been highlighted. IVDs are the largest avascular structures in the human body and determine the hypoxic and glycolytic features of nucleus pulposus (NP) cells. Accumulating evidence has demonstrated that intracellular metabolic dysfunction is associated with IVD degeneration, but a comprehensive review is lacking. Here, by reviewing the physiological features of IVDs, pathological processes and metabolic changes associated with IVD degeneration and the functions of metabolic genes in IVDs, we highlight that glycolytic pathway and intact mitochondrial function are essential for IVD homeostasis. In degenerated NPs, glycolysis and mitochondrial function are downregulated. Boosting glycolysis such as HIF1α overexpression protects against IVD degeneration. Moreover, the correlations between metabolic diseases such as diabetes, obesity and IVD degeneration and their underlying molecular mechanisms are discussed. Hyperglycemia in diabetic diseases leads to cell senescence, the senescence-associated phenotype (SASP), apoptosis and catabolism of extracellualr matrix in IVDs. Correcting the global metabolic disorders such as insulin or GLP-1 receptor agonist administration is beneficial for diabetes associated IVD degeneration. Overall, we summarized the recent progress of investigations on metabolic contributions to IVD degeneration and provide a new perspective that correcting metabolic dysfunction may be beneficial for treating IVD degeneration.
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Affiliation(s)
- Chao Song
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Peixuan Hu
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Renpeng Peng
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China
| | - Feng Li
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China.
| | - Zhong Fang
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China.
| | - Yong Xu
- Department of Orthopaedic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China.
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2
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Couasnay G, Garcia H, Elefteriou F. A comparative analysis of TonEBP conditional knockout mouse models reveals inter-dependency between compartments of the intervertebral disc. Development 2024; 151:dev202354. [PMID: 38421307 PMCID: PMC11006390 DOI: 10.1242/dev.202354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 02/20/2024] [Indexed: 03/02/2024]
Abstract
Interactions between notochord and sclerotome are required for normal embryonic spine patterning, but whether the postnatal derivatives of these tissues also require interactions for postnatal intervertebral disc (IVD) growth and maintenance is less established. We report here the comparative analysis of four conditional knockout mice deficient for TonEBP, a transcription factor known to allow cells to adapt to changes in extracellular osmotic pressure, in specific compartments of the IVD. We show that TonEBP deletion in nucleus pulposus (NP) cells does not affect their survival or aggrecan expression, but promoted cell proliferation in the NP and in adjacent vertebral growth plates (GPs). In cartilage end plates/GPs, TonEBP deletion induced cell death, but also structural alterations in the adjacent NP cells and vertebral bodies. Embryonic or postnatal TonEBP loss generated similar IVD changes. In addition to demonstrating the requirement of TonEBP in the different compartments of the IVD, this comparative analysis uncovers the in vivo interdependency of the different IVD compartments during the growth of the postnatal IVD-vertebral units.
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Affiliation(s)
- Greig Couasnay
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Haley Garcia
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Florent Elefteriou
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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3
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Xie W, Xing Y, Xiao L, Zhang P, Oh R, Zhang Y, Yu X, He Y, Oh EG, Cao R, Ramasubramanian MK, Wang Y, Jin L, Oberhozler J, Li X. Intervertebral Disc-on-a-Chip MF: A New Model for Mouse Disc Culture via Integrating Mechanical Loading and Dynamic Media Flow. ADVANCED MATERIALS TECHNOLOGIES 2023; 8:2300606. [PMID: 39130370 PMCID: PMC11315454 DOI: 10.1002/admt.202300606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Indexed: 08/13/2024]
Abstract
This study aims to develop an ex vivo organ-on-a-chip model, intervertebral Disc-on-a-ChipMF, to investigate integrated effects of mechanical loading and nutrition on disc health. The system consists of a detachable multilayer microfluidic chip, a Computer-Arduino-based control system, and a mechanical loading unit, which were optimized for accurate axial force measurement and the maintenance of a 21-day ex vivo disc culture. To ensure accuracy of axial force, we optimized the axial mechanical loading regimen, used the Computer-Arduino-based system and low-profile force sensors (LPFS) to control the mechanical loading unit, and modeled the force distribution by using computational simulation. A 21-day ex vivo disc culture was demonstrated using the Disc-on-a-ChipMF system, with optimized mechanical loading (0.02 MPa at 1Hz, 1.5 hr/day) and flow rate (1 μL/min). The structural integrity, collagen breakdown, catabolic enzyme activities, and disc cell and collagen alignment revealed that the on-chip cultured discs exhibited a preferred disc health similar to that of native discs for up to 21 days, while discs in a static culture showed detrimental degenerative changes. The mouse Disc-on-a-ChipMF system mimics in vivo disc microenvironment and provides a valuable platform for studying the effects of various factors on disc health and degeneration and testing new therapies.
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Affiliation(s)
- Wanqing Xie
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Yuan Xing
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, VA 22908, USA
| | - Li Xiao
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Pu Zhang
- Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer’s Way, Charlottesville, VA 22904, USA
| | - Richard Oh
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Yangpu Zhang
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
- Current address: Department of Orthopaedic Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
| | - Xiaoyu Yu
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, VA 22908, USA
| | - Yi He
- Department of Surgery, University of Virginia, 345 Cripell Drive, Charlottesville, VA 22908, USA
| | - Eunha G Oh
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Ruofan Cao
- Department of BioMolecular Science, University of Mississippi, Oxford, MS 38677, USA
| | - Melur K Ramasubramanian
- Department of Mechanical and Aerospace Engineering, University of Virginia, 122 Engineer’s Way, Charlottesville, VA 22904, USA
| | - Yong Wang
- Department of Visceral Surgery and Transplantation, University of Zurich Hospital, 8091 Zürich, Switzerland
| | - Li Jin
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
| | - Jose Oberhozler
- Department of Visceral Surgery and Transplantation, University of Zurich Hospital, 8091 Zürich, Switzerland
| | - Xudong Li
- Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA 22908, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22904, USA
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4
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Lu Z, Chen P, Xu Q, Li B, Jiang S, Jiang L, Zheng X. Constitutive and conditional gene knockout mice for the study of intervertebral disc degeneration: Current status, decision considerations, and future possibilities. JOR Spine 2023; 6:e1242. [PMID: 36994464 PMCID: PMC10041386 DOI: 10.1002/jsp2.1242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 12/13/2022] [Accepted: 12/22/2022] [Indexed: 01/09/2023] Open
Abstract
There have been an increasing number of patients with degenerative disc diseases due to the aging population. In light of this, studies on the pathogenesis of intervertebral disc degeneration have become a hot topic, and gene knockout mice have become a valuable tool in this field of research. With the development of science and technology, constitutive gene knockout mice can be constructed using homologous recombination, zinc finger nuclease, transcription activator-like effector nuclease technology and clustered regularly interspaced short palindromic repeats/Cas9 (CRISPR/Cas9) system, and conditional gene knockout mice can be constructed using the Cre/LoxP system. The gene-edited mice using these techniques have been widely used in the studies on disc degeneration. This paper reviews the development process and principles of these technologies, functions of the edited genes in disc degeneration, advantages, and disadvantages of different methods and possible targets of the specific Cre recombinase in intervertebral discs. Recommendations for the choice of suitable gene-edited model mice are presented. At the same time, possible technological improvements in the future are also discussed.
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Affiliation(s)
- Ze‐Yu Lu
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Peng‐Bo Chen
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Qing‐Yin Xu
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Bo Li
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Sheng‐Dan Jiang
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Lei‐Sheng Jiang
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
| | - Xin‐Feng Zheng
- Spine Center Xinhua Hospital, Shanghai Jiao Tong University School of Medicine Shanghai China
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Li X, Yang S, Yuan G, Jing D, Qin L, Zhao H, Yang S. Type II collagen-positive progenitors are important stem cells in controlling skeletal development and vascular formation. Bone Res 2022; 10:46. [PMID: 35739091 PMCID: PMC9226163 DOI: 10.1038/s41413-022-00214-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 04/10/2022] [Indexed: 02/07/2023] Open
Abstract
Type II collagen-positive (Col2+) cells have been reported as skeletal stem cells (SSCs), but the contribution of Col2+ progenitors to skeletal development both prenatally and postnatally during aging remains unclear. To address this question, we generated new mouse models with ablation of Col2+ cells at either the embryonic or postnatal stages. The embryonic ablation of Col2+ progenitors resulted in the death of newborn mice due to a decrease in skeletal blood vessels, loss of all vertebral bones and absence of most other bones except part of the craniofacial bone, the clavicle bone and a small piece of the long bone and ribs, which suggested that intramembranous ossification is involved in long bone development but does not participate in spine development. The postnatal ablation of Col2+ cells resulted in mouse growth retardation and a collagenopathy phenotype. Lineage tracing experiments with embryonic or postnatal mice revealed that Col2+ progenitors occurred predominantly in the growth plate (GP) and articular cartilage, but a limited number of Col2+ cells were detected in the bone marrow. Moreover, the number and differentiation ability of Col2+ progenitors in the long bone and knee joints decreased with increasing age. The fate-mapping study further revealed Col2+ lineage cells contributed to, in addition to osteoblasts and chondrocytes, CD31+ blood vessels in both the calvarial bone and long bone. Specifically, almost all blood vessels in calvarial bone and 25.4% of blood vessels in long bone were Col2+ lineage cells. However, during fracture healing, 95.5% of CD31+ blood vessels in long bone were Col2+ lineage cells. In vitro studies further confirmed that Col2+ progenitors from calvarial bone and GP could form CD31+ vascular lumens. Thus, this study provides the first demonstration that intramembranous ossification is involved in long bone and rib development but not spine development. Col2+ progenitors contribute to CD31+ skeletal blood vessel formation, but the percentage differs between long bone and skull bone. The number and differentiation ability of Col2+ progenitors decreases with increasing age.
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Affiliation(s)
- Xinhua Li
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200080, P. R. China
- Department of Spinal Surgery, East Hospital, Tongji University, School of Medicine, Shanghai, 200120, China
| | - Shuting Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gongsheng Yuan
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Dian Jing
- Department of Restorative Sciences, College of Dentistry, Texas A&M University, Dallas, TX, USA
| | - Ling Qin
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hu Zhao
- Department of Restorative Sciences, College of Dentistry, Texas A&M University, Dallas, TX, USA
| | - Shuying Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Couasnay G, Madel MB, Lim J, Lee B, Elefteriou F. Sites of Cre-recombinase activity in mouse lines targeting skeletal cells. J Bone Miner Res 2021; 36:1661-1679. [PMID: 34278610 DOI: 10.1002/jbmr.4415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/12/2021] [Accepted: 07/15/2021] [Indexed: 12/22/2022]
Abstract
The Cre/Lox system is a powerful tool in the biologist's toolbox, allowing loss-of-function and gain-of-function studies, as well as lineage tracing, through gene recombination in a tissue-specific and inducible manner. Evidence indicates, however, that Cre transgenic lines have a far more nuanced and broader pattern of Cre activity than initially thought, exhibiting "off-target" activity in tissues/cells other than the ones they were originally designed to target. With the goal of facilitating the comparison and selection of optimal Cre lines to be used for the study of gene function, we have summarized in a single manuscript the major sites and timing of Cre activity of the main Cre lines available to target bone mesenchymal stem cells, chondrocytes, osteoblasts, osteocytes, tenocytes, and osteoclasts, along with their reported sites of "off-target" Cre activity. We also discuss characteristics, advantages, and limitations of these Cre lines for users to avoid common risks related to overinterpretation or misinterpretation based on the assumption of strict cell-type specificity or unaccounted effect of the Cre transgene or Cre inducers. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Greig Couasnay
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA
| | | | - Joohyun Lim
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Florent Elefteriou
- Department of Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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7
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Li X, Yang S, Qin L, Yang S. Type II collagen-positive embryonic progenitors are the major contributors to spine and intervertebral disc development and repair. Stem Cells Transl Med 2021; 10:1419-1432. [PMID: 34032373 PMCID: PMC8459639 DOI: 10.1002/sctm.20-0424] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/23/2021] [Accepted: 02/16/2021] [Indexed: 12/23/2022] Open
Abstract
Type II collagen-positive embryonic progenitors are the major contributors to spine and intervertebral disc development and repair has been removed because it was published by mistake. The article will be published on October 1, 2021.
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Affiliation(s)
- Xinhua Li
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Department of Spinal Surgery, East Hospital, Tongji University, School of Medicine, Shanghai, People's Republic of China
| | - Shuting Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ling Qin
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shuying Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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8
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Zhang Y, Tian Z, Gerard D, Yao L, Shofer FS, Cs-Szabo G, Qin L, Pacifici M, Enomoto-Iwamoto M. Elevated inflammatory gene expression in intervertebral disc tissues in mice with ADAM8 inactivated. Sci Rep 2021; 11:1804. [PMID: 33469101 PMCID: PMC7815795 DOI: 10.1038/s41598-021-81495-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 12/31/2020] [Indexed: 12/24/2022] Open
Abstract
We found ADAM8 enzymatic activity elevated in degenerative human intervertebral disc (IVD). Here, we examined the discs in ADAM8-inactivation mice that carry a mutation preventing self-activation of the enzyme. Surprisingly, elevated gene expression for inflammatory markers (Cxcl1, IL6) was observed in injured discs of ADAM8 mutant mice, along with elevated expression of type 2 collagen gene (Col2a1), compared with wild type controls. Injured annulus fibrosus of mutant and wild type mice contained a higher proportion of large collagen fibers compared with intact discs, as documented by microscopic examination under circular polarized light. In the intact IVDs, Adam8EQ mouse AF contained lower proportion of yellow (intermediate) fiber than WT mice. This suggests that ADAM8 may regulate inflammation and collagen fiber assembly. The seemingly contradictory findings of elevated inflammatory markers in mutant mice and excessive ADAM8 activity in human degenerative discs suggest that ADAM8 may interact with other enzymatic and pro-inflammatory processes needed for tissue maintenance and repair. As a future therapeutic intervention to retard intervertebral disc degeneration, partial inhibition of ADAM8 proteolysis may be more desirable than complete inactivation of this enzyme.
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Affiliation(s)
- Yejia Zhang
- Department of Physical Medicine & Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
- Translational Musculoskeletal Research Center (TMRC), Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, PA, USA.
| | - Zuozhen Tian
- Department of Physical Medicine & Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - David Gerard
- Department of Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Lutian Yao
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
- Department of Orthopaedics/Sports Medicine and Joint Surgery, First Affiliated Hospital, China Medical University, Shenyang, Liaoning, China
| | - Frances S Shofer
- Emergency Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Gabriella Cs-Szabo
- Department of Biochemistry, Rush University Medical Center, Chicago, IL, USA
| | - Ling Qin
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - Maurizio Pacifici
- Division of Orthopaedic Surgery, The Children's Hospital of Philadelphia, Philadelphia, USA
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Zeldin L, Mosley GE, Laudier D, Gallate ZS, Gansau J, Hoy RC, Poeran J, Iatridis JC. Spatial mapping of collagen content and structure in human intervertebral disk degeneration. JOR Spine 2020; 3:e1129. [PMID: 33392461 PMCID: PMC7770200 DOI: 10.1002/jsp2.1129] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 12/11/2022] Open
Abstract
Collagen plays a key structural role in both the annulus fibrosus (AF) and nucleus pulposus (NP) of intervertebral disks (IVDs). Changes in collagen content with degeneration suggest a shift from collagen type II to type I within the NP, and the activation of pro-inflammatory factors is indicative of fibrosis throughout. While IVD degeneration is considered a fibrotic process, an increase in collagen content with degeneration, reflective of fibrosis, has not been demonstrated. Additionally, changes in collagen content and structure in human IVDs with degeneration have not been characterized with high spatial resolution. The collagen content of 23 human lumbar L2/3 or L3/4 IVDs was quantified using second harmonic generation imaging (SHG) and multiple image processing algorithms, and these parameters were correlated with the Rutges histological degeneration grade. In the NP, SHG intensity increased with degeneration grade, suggesting fibrotic collagen deposition. In the AF, the entropy of SHG intensity was reduced with degeneration indicating increased collagen uniformity and suggesting less-organized lamellar structure. Collagen orientation entropy decreased throughout most IVD regions with increasing degeneration grade, further supporting a loss in collagen structural complexity. Overall, SHG imaging enabled visualization and quantification of IVD collagen content and organization with degeneration. There was an observed shift from an initially complex structure to more uniform structure with loss of microstructural elements and increased NP collagen polarity, suggesting fibrotic remodeling.
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Affiliation(s)
- Lawrence Zeldin
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Grace E. Mosley
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Damien Laudier
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Zachary S. Gallate
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Jennifer Gansau
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Robert C. Hoy
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - Jashvant Poeran
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
- Department of Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
| | - James C. Iatridis
- Leni & Peter W. May Department of OrthopedicsIcahn School of Medicine at Mount SinaiNew YorkNew YorkUSA
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10
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Piprode V, Mohanty S, Bonavita R, Loh S, Anbazhagan R, Saini C, Pinelli R, Pricop P, Dahia CL. An optimized step-by-step protocol for isolation of nucleus pulposus, annulus fibrosus, and end plate cells from the mouse intervertebral discs and subsequent preparation of high-quality intact total RNA. JOR Spine 2020; 3:e1108. [PMID: 33015579 PMCID: PMC7524240 DOI: 10.1002/jsp2.1108] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/27/2020] [Accepted: 06/29/2020] [Indexed: 12/14/2022] Open
Abstract
Intervertebral disc degeneration is the most significant, and least understood, cause of chronic back pain, affecting almost one in seven individuals at some point of time. Each intervertebral disc has three components; central nucleus pulposus (NP), concentric layers of annulus fibrosus (AF), and a pair of end plate (EP) that connects the disc to the vertebral bodies. Understanding the molecular and cellular basis of intervertebral disc growth, health, and aging will generate significant information for developing therapeutic approaches. Rapid and efficient preparations of homogeneous and pure cells are crucial for meaningful and rigorous downstream analysis at the cellular, molecular, and biochemical level. Cross-sample contamination may influence the interpretation of the results. In addition to altering gene expression, slow or delayed isolation procedures will also cause the degradation of cells and biomolecules that create a bias in the outcomes of the study. The mouse model system is extensively used to understand the intervertebral disc biology. Here we describe two protocols: (a) for efficient isolation of pure NP, AF, and EP cells from mouse lumbar intervertebral disc. We validated the purity of the NP and AF cells using Shh Cre/+ ; R26 mT/mG/+ dual-fluorescent reporter mice where all NP cells are GPF+ve, and by the sensitive approach of qPCR analysis using TaqMan probes for Shh, and Brachyury as NP-specific markers, Tenomodulin as AF-specific marker, and Osteocalcin as bone-specific marker. (b) For isolation of high-quality intact RNA with RIN of 9.3 to 10 from disc cells. These methods will be useful for the rigorous analysis of NP and AF cells, and improve our understanding of intervertebral disc biology.
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Affiliation(s)
| | | | | | - Sarah Loh
- Hospital for Special Surgery New York New York USA
| | | | | | | | - Paul Pricop
- Hospital for Special Surgery New York New York USA
| | - Chitra L Dahia
- Hospital for Special Surgery New York New York USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine Graduate School of Medical Sciences New York New York USA
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