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Diekman BO, Loeser RF. Aging and the emerging role of cellular senescence in osteoarthritis. Osteoarthritis Cartilage 2024; 32:365-371. [PMID: 38049031 PMCID: PMC10984800 DOI: 10.1016/j.joca.2023.11.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 11/21/2023] [Accepted: 11/29/2023] [Indexed: 12/06/2023]
Abstract
OBJECTIVE The correlation between age and incidence of osteoarthritis (OA) is well known but the causal mechanisms involved are not completely understood. This narrative review summarizes selected key findings from the past 30 years that have elucidated key aspects of the relationship between aging and OA. METHODS The peer-reviewed English language literature was searched on PubMed using keywords including senescence, aging, cartilage, and osteoarthritis, for original studies and reviews published from 1993 to 2023 with a major focus on more recent studies. Manuscripts most relevant to aging and OA that examined one or more of the hallmarks of aging were selected for further review. RESULTS All proposed hallmarks of aging have been observed in articular cartilage and some have also been described in other joint tissues. Hallmarks include genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, disabled macroautophagy, chronic inflammation, and dysbiosis. There is evidence that these age-related changes contribute to the development of OA in part by promoting cellular senescence. Senescence may therefore serve as a downstream mediator that connects numerous aging hallmarks to OA, likely through the senescence-associated secretory phenotype that is characterized by increased production of proinflammatory cytokines and matrix metalloproteinases. CONCLUSIONS Progress over the past 30 years has provided the foundation for emerging therapies, such as senolytics and senomorphics, that hold promise for OA disease modification. Mechanistic studies utilizing physiologically-aged animals and cadaveric human joint tissues will be important for continued progress.
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Affiliation(s)
- Brian O Diekman
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, 27599, USA.
| | - Richard F Loeser
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Division of Rheumatology, Allergy, and Immunology, University of North Carolina, Chapel Hill, NC, 27599, USA.
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Diekman BO, Loeser RF. DNA Damage and Cellular Senescence in Osteoarthritis: An Unexpected Role for Interferon Regulatory Factor 1 in Chondrocyte DNA Repair. Arthritis Rheumatol 2024. [PMID: 38343350 DOI: 10.1002/art.42822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/03/2024] [Accepted: 02/08/2024] [Indexed: 02/29/2024]
Affiliation(s)
- Brian O Diekman
- University of North Carolina, Chapel Hill, and North Carolina State University, Raleigh
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Rich MJ, Burnash S, Krishnan RR, Chubinskaya S, Loeser RF, Polacheck WJ, Diekman BO. Use of a novel magnetically actuated compression system to study the temporal dynamics of axial and lateral strain in human osteochondral plugs. J Biomech 2024; 162:111887. [PMID: 38128469 PMCID: PMC10872462 DOI: 10.1016/j.jbiomech.2023.111887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 10/23/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
The high water content of articular cartilage allows this biphasic tissue to withstand large compressive loads through fluid pressurization. The system presented here, termed the "MagnaSquish", provides new capabilities for quantifying the effect of rehydration on cartilage behavior during cyclic loading. An imbalanced rate of fluid exudation during load and fluid re-entry during recovery can lead to the accumulation of strain during successive loading cycles - a phenomenon known as ratcheting. Typical experimental systems for cartilage biomechanics use continuous contact between the platen and sample, which may affect tissue rehydration by compressing the top layer of cartilage and slowing fluid re-entry. To address this limitation, we developed a magnetically actuated device that provides full lift-off of the platen in between loading cycles. We investigated strain accumulation in cadaveric human osteochondral plugs during 750 loading cycles, with two dimensional profiles of the cartilage captured at 30 frames per second throughout loading and 10 min of additional free swelling recovery. Axial and lateral strain measurements were extracted from the tissue profiles using a UNet-based deep learning algorithm to circumvent manual tracing. We observed increased axial strain accumulation with shorter inter-cycle recovery, with static loading serving as the extreme case of zero recovery. The loading waveform during the 750 cycles dictated the pace of the recovery during the extended free swelling period, as shorter inter-cycle recovery led to more persistent axial strain accumulation for up to five minutes. This work showcases the importance of fluid re-entry in resisting strain accumulation during cyclical compression.
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Affiliation(s)
- Matthew J Rich
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, United States; Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States
| | - Sarah Burnash
- Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States
| | - Rohan R Krishnan
- Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, United States
| | - Richard F Loeser
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, United States; Department of Cell Biology and Physiology, UNC, United States; Division of Rheumatology, Allergy, and Immunology, UNC, United States
| | - William J Polacheck
- Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States; Department of Cell Biology and Physiology, UNC, United States; McAllister Heart Institute, UNC, United States
| | - Brian O Diekman
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill (UNC), Chapel Hill, NC, United States; Joint Department of Biomedical Engineering, UNC and North Carolina State University, Raleigh, NC, United States; Department of Cell Biology and Physiology, UNC, United States.
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Copp ME, Shine J, Brown HL, Nimmala KR, Hansen OB, Chubinskaya S, Collins JA, Loeser RF, Diekman BO. Sirtuin 6 activation rescues the age-related decline in DNA damage repair in primary human chondrocytes. Aging (Albany NY) 2023; 15:13628-13645. [PMID: 38078876 PMCID: PMC10756124 DOI: 10.18632/aging.205394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 11/15/2023] [Indexed: 12/21/2023]
Abstract
While advanced age is widely recognized as the greatest risk factor for osteoarthritis (OA), the biological mechanisms behind this connection remain unclear. Previous work has demonstrated that chondrocytes from older cadaveric donors have elevated levels of DNA damage as compared to chondrocytes from younger donors. The purpose of this study was to determine whether a decline in DNA repair efficiency is one explanation for the accumulation of DNA damage with age, and to quantify the improvement in repair with activation of Sirtuin 6 (SIRT6). After acute damage with irradiation, DNA repair was shown to be more efficient in chondrocytes from young (≤45 years old) as compared to middle-aged (50-65 years old) or older (>70 years old) cadaveric donors. Activation of SIRT6 with MDL-800 improved the repair efficiency, while inhibition with EX-527 reduced the rate of repair and increased the percentage of cells that retain high levels of damage. In addition to affecting repair after acute damage, treating chondrocytes from older donors with MDL-800 for 48 hours significantly reduced the amount of baseline DNA damage. Chondrocytes isolated from the knees of mice between 4 months and 22 months of age revealed both an increase in DNA damage with aging, and a decrease in DNA damage following MDL-800 treatment. Lastly, treating murine cartilage explants with MDL-800 lowered the percentage of chondrocytes with high p16 promoter activity, which supports the concept that using SIRT6 activation to maintain low levels of DNA damage may prevent the initiation of senescence.
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Affiliation(s)
- Michaela E. Copp
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC 27606, USA
| | - Jacqueline Shine
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hannon L. Brown
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC 27606, USA
| | - Kirti R. Nimmala
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC 27606, USA
| | - Oliver B. Hansen
- School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL 60612, USA
| | - John A. Collins
- Department of Orthopedic Surgery, Thomas Jefferson University, Philadelphia, PA 19144, USA
| | - Richard F. Loeser
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Division of Rheumatology, Allergy, and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Brian O. Diekman
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC 27606, USA
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Miao MZ, Su QP, Cui Y, Bahnson EM, Li G, Wang M, Yang Y, Collins JA, Wu D, Gu Q, Chubinskaya S, Diekman BO, Yamada KM, Loeser RF. Redox-active endosomes mediate α5β1 integrin signaling and promote chondrocyte matrix metalloproteinase production in osteoarthritis. Sci Signal 2023; 16:eadf8299. [PMID: 37906629 PMCID: PMC10666734 DOI: 10.1126/scisignal.adf8299] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 10/10/2023] [Indexed: 11/02/2023]
Abstract
Mechanical cues sensed by integrins induce cells to produce proteases to remodel the extracellular matrix. Excessive protease production occurs in many degenerative diseases, including osteoarthritis, in which articular cartilage degradation is associated with the genesis of matrix protein fragments that can activate integrins. We investigated the mechanisms by which integrin signals may promote protease production in response to matrix changes in osteoarthritis. Using a fragment of the matrix protein fibronectin (FN) to activate the α5β1 integrin in primary human chondrocytes, we found that endocytosis of the integrin and FN fragment complex drove the production of the matrix metalloproteinase MMP-13. Activation of α5β1 by the FN fragment, but not by intact FN, was accompanied by reactive oxygen species (ROS) production initially at the cell surface, then in early endosomes. These ROS-producing endosomes (called redoxosomes) contained the integrin-FN fragment complex, the ROS-producing enzyme NADPH oxidase 2 (NOX2), and SRC, a redox-regulated kinase that promotes MMP-13 production. In contrast, intact FN was endocytosed and trafficked to recycling endosomes without inducing ROS production. Articular cartilage from patients with osteoarthritis showed increased amounts of SRC and the NOX2 complex component p67phox. Furthermore, we observed enhanced localization of SRC and p67phox at early endosomes, suggesting that redoxosomes could transmit and sustain integrin signaling in response to matrix damage. This signaling mechanism not only amplifies the production of matrix-degrading proteases but also establishes a self-perpetuating cycle that contributes to the ongoing degradation of cartilage matrix in osteoarthritis.
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Affiliation(s)
- Michael Z. Miao
- Division of Rheumatology, Allergy, and Immunology and the Thurston Arthritis Research Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Division of Oral & Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Curriculum in Oral and Craniofacial Biomedicine, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Qian Peter Su
- School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Yang Cui
- Division of Rheumatology, Allergy, and Immunology and the Thurston Arthritis Research Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Edward M. Bahnson
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Gang Li
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195, USA
- eScience Institute, University of Washington, Seattle, WA, 98195, USA
| | - Menglin Wang
- Division of Pharmacoengineering and Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Yuchen Yang
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - John A. Collins
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Di Wu
- Division of Oral & Craniofacial Health Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, NC, 27599, USA
| | - Qisheng Gu
- Shanghai Institute of Immunity and Infection, Chinese Academy of Sciences, Shanghai, 200031, China
- Department of Immunology, Université Paris Cité, Paris, 75006, France
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, 60612, USA
| | - Brian O. Diekman
- Division of Rheumatology, Allergy, and Immunology and the Thurston Arthritis Research Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, 27695, USA
| | - Kenneth M. Yamada
- Cell Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Richard F. Loeser
- Division of Rheumatology, Allergy, and Immunology and the Thurston Arthritis Research Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Cui Y, Miao MZ, Wang M, Su QP, Qiu K, Arbeeva L, Chubinskaya S, Diekman BO, Loeser RF. Yes-associated protein nuclear translocation promotes anabolic activity in human articular chondrocytes. Osteoarthritis Cartilage 2023; 31:1078-1090. [PMID: 37100374 PMCID: PMC10524185 DOI: 10.1016/j.joca.2023.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 03/27/2023] [Accepted: 04/06/2023] [Indexed: 04/28/2023]
Abstract
OBJECTIVE Yes-associated protein (YAP) has been widely studied as a mechanotransducer in many cell types, but its function in cartilage is controversial. The aim of this study was to identify the effect of YAP phosphorylation and nuclear translocation on the chondrocyte response to stimuli relevant to osteoarthritis (OA). DESIGN Cultured normal human articular chondrocytes from 81 donors were treated with increased osmolarity media as an in vitro model of mechanical stimulation, fibronectin fragments (FN-f) or IL-1β as catabolic stimuli, and IGF-1 as an anabolic stimulus. YAP function was assessed with gene knockdown and inhibition by verteporfin. Nuclear translocation of YAP and its transcriptional co-activator TAZ and site-specific YAP phosphorylation were determined by immunoblotting. Immunohistochemistry and immunofluorescence to detect YAP were performed on normal and OA human cartilage with different degrees of damage. RESULTS Chondrocyte YAP/TAZ nuclear translocation increased under physiological osmolarity (400 mOsm) and IGF-1 stimulation, which was associated with YAP phosphorylation at Ser128. In contrast, catabolic stimulation decreased the levels of nuclear YAP/TAZ through YAP phosphorylation at Ser127. Following YAP inhibition, anabolic gene expression and transcriptional activity decreased. Additionally, YAP knockdown reduced proteoglycan staining and levels of type II collagen. Total YAP immunostaining was greater in OA cartilage, but YAP was sequestered in the cytosol in cartilage areas with more severe damage. CONCLUSIONS YAP chondrocyte nuclear translocation is regulated by differential phosphorylation in response to anabolic and catabolic stimuli. Decreased nuclear YAP in OA chondrocytes may contribute to reduced anabolic activity and promotion of further cartilage loss.
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Affiliation(s)
- Y Cui
- Xiangya International Medical Center, Xiangya Hospital, Central South University, Changsha, Hunan Province, 410008, China; Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA.
| | - M Z Miao
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Division of Oral & Craniofacial Health Sciences, University of North Carolina Adams School of Dentistry, Chapel Hill, NC, 27599, USA.
| | - M Wang
- Division of Pharmacoengineering and Molecular Pharmaceutics, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC, 27599, USA.
| | - Q P Su
- School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| | - K Qiu
- Division of Pharmacoengineering and Molecular Pharmaceutics, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC, 27599, USA.
| | - L Arbeeva
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA.
| | - S Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, 60612, USA.
| | - B O Diekman
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, 27599, USA.
| | - R F Loeser
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA.
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Doherty EL, Aw WY, Warren EC, Hockenberry M, Whitworth CP, Krohn G, Howell S, Diekman BO, Legant WR, Nia HT, Hickey AJ, Polacheck WJ. Patient-derived extracellular matrix demonstrates role of COL3A1 in blood vessel mechanics. Acta Biomater 2023; 166:346-359. [PMID: 37187299 PMCID: PMC10330735 DOI: 10.1016/j.actbio.2023.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 05/17/2023]
Abstract
Vascular Ehlers-Danlos Syndrome (vEDS) is a rare autosomal dominant disease caused by mutations in the COL3A1 gene, which renders patients susceptible to aneurysm and arterial dissection and rupture. To determine the role of COL3A1 variants in the biochemical and biophysical properties of human arterial ECM, we developed a method for synthesizing ECM directly from vEDS donor fibroblasts. We found that the protein content of the ECM generated from vEDS donor fibroblasts differed significantly from ECM from healthy donors, including upregulation of collagen subtypes and other proteins related to ECM structural integrity. We further found that ECM generated from a donor with a glycine substitution mutation was characterized by increased glycosaminoglycan content and unique viscoelastic mechanical properties, including increased time constant for stress relaxation, resulting in a decrease in migratory speed of human aortic endothelial cells when seeded on the ECM. Collectively, these results demonstrate that vEDS patient-derived fibroblasts harboring COL3A1 mutations synthesize ECM that differs in composition, structure, and mechanical properties from healthy donors. These results further suggest that ECM mechanical properties could serve as a prognostic indicator for patients with vEDS, and the insights provided by the approach demonstrate the broader utility of cell-derived ECM in disease modeling. STATEMENT OF SIGNIFICANCE: The role of collagen III ECM mechanics remains unclear, despite reported roles in diseases including fibrosis and cancer. Here, we generate fibrous, collagen-rich ECM from primary donor cells from patients with vascular Ehlers-Danlos syndrome (vEDS), a disease caused by mutations in the gene that encodes collagen III. We observe that ECM grown from vEDS patients is characterized by unique mechanical signatures, including altered viscoelastic properties. By quantifying the structural, biochemical, and mechanical properties of patient-derived ECM, we identify potential drug targets for vEDS, while defining a role for collagen III in ECM mechanics more broadly. Furthermore, the structure/function relationships of collagen III in ECM assembly and mechanics will inform the design of substrates for tissue engineering and regenerative medicine.
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Affiliation(s)
- Elizabeth L Doherty
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA; UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Wen Yih Aw
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA; UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Emily C Warren
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA
| | - Max Hockenberry
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA; Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Chloe P Whitworth
- Department of Genetics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Grace Krohn
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA
| | - Stefanie Howell
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brian O Diekman
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA
| | - Wesley R Legant
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA; Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Hadi Tavakoli Nia
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Anthony J Hickey
- UNC Catalyst for Rare Diseases, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - William J Polacheck
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, NC, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA; McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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Richard D, Capellini TD, Diekman BO. Epigenetics as a mediator of genetic risk in osteoarthritis: role during development, homeostasis, aging, and disease progression. Am J Physiol Cell Physiol 2023; 324:C1078-C1088. [PMID: 36971423 PMCID: PMC10191130 DOI: 10.1152/ajpcell.00574.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023]
Abstract
The identification of genomic loci that are associated with osteoarthritis (OA) has provided a starting point for understanding how genetic variation activates catabolic processes in the joint. However, genetic variants can only alter gene expression and cellular function when the epigenetic environment is permissive to these effects. In this review, we provide examples of how epigenetic shifts at distinct life stages can alter the risk for OA, which we posit is critical for the proper interpretation of genome-wide association studies (GWAS). During development, intensive work on the growth and differentiation factor 5 (GDF5) locus has revealed the importance of tissue-specific enhancer activity in controlling both joint development and the subsequent risk for OA. During homeostasis in adults, underlying genetic risk factors may help establish beneficial or catabolic "set points" that dictate tissue function, with a strong cumulative effect on OA risk. During aging, methylation changes and the reorganization of chromatin can "unmask" the effects of genetic variants. The destructive function of variants that alter aging would only mediate effects after reproductive competence and thus avoid any evolutionary selection pressure, as consistent with larger frameworks of biological aging and its relationship to disease. A similar "unmasking" may occur during OA progression, which is supported by the finding of distinct expression quantitative trait loci (eQTLs) in chondrocytes depending on the degree of tissue degradation. Finally, we propose that massively parallel reporter assays (MPRAs) will be a valuable tool to test the function of putative OA GWAS variants in chondrocytes from different life stages.
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Affiliation(s)
- Daniel Richard
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States
| | - Terence D Capellini
- Department of Human Evolutionary Biology, Harvard University, Cambridge, Massachusetts, United States
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States
| | - Brian O Diekman
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, and North Carolina State University, Raleigh, North Carolina, United States
- Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
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Copp ME, Shine J, Brown HL, Nimmala KR, Chubinskaya S, Collins JA, Loeser RF, Diekman BO. SIRT6 activation rescues the age-related decline in DNA damage repair in primary human chondrocytes. bioRxiv 2023:2023.02.27.530205. [PMID: 36909504 PMCID: PMC10002640 DOI: 10.1101/2023.02.27.530205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
While advanced age has long been recognized as the greatest risk factor for osteoarthritis (OA), the biological mechanisms behind this connection remain unclear. Previous work has demonstrated that chondrocytes from older cadaveric donors have elevated levels of DNA damage as compared to chondrocytes from younger donors. The purpose of this study was to determine whether a decline in DNA repair efficiency is one explanation for the accumulation of DNA damage with age, and to quantify the improvement in repair with activation of Sirtuin 6 (SIRT6). Using an acute irradiation model to bring the baseline level of all donors to the same starting point, this study demonstrates a decline in repair efficiency during aging when comparing chondrocytes from young (≤45 years old), middle-aged (50-65 years old), or older (>70 years old) cadaveric donors with no known history of OA or macroscopic cartilage degradation at isolation. Activation of SIRT6 in middle-aged chondrocytes with MDL-800 (20 μM) improved the repair efficiency, while inhibition with EX-527 (10 μM) inhibited the rate of repair and the increased the percentage of cells that retained high levels of damage. Treating chondrocytes from older donors with MDL-800 for 48 hours significantly reduced the amount of DNA damage, despite this damage having accumulated over decades. Lastly, chondrocytes isolated from the proximal femurs of mice between 4 months and 22 months of age revealed both an increase in DNA damage with aging, and a decrease in DNA damage following MDL-800 treatment.
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Affiliation(s)
- Michaela E Copp
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC
| | - Jacqueline Shine
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Hannon L Brown
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC
| | - Kirti R Nimmala
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL
| | - John A Collins
- Department of Orthopedic Surgery, Thomas Jefferson University
| | - Richard F Loeser
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Division of Rheumatology, Allergy, and Immunology, University of North Carolina
| | - Brian O Diekman
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC
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10
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Thulson E, Davis ES, D’Costa S, Coryell PR, Kramer NE, Mohlke KL, Loeser RF, Diekman BO, Phanstiel DH. 3D chromatin structure in chondrocytes identifies putative osteoarthritis risk genes. Genetics 2022; 222:iyac141. [PMID: 36099032 PMCID: PMC9713432 DOI: 10.1093/genetics/iyac141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/29/2022] [Indexed: 12/13/2022] Open
Abstract
Genome-wide association studies have identified over 100 loci associated with osteoarthritis risk, but the majority of osteoarthritis risk variants are noncoding, making it difficult to identify the impacted genes for further study and therapeutic development. To address this need, we used a multiomic approach and genome editing to identify and functionally characterize potential osteoarthritis risk genes. Computational analysis of genome-wide association studies and ChIP-seq data revealed that chondrocyte regulatory loci are enriched for osteoarthritis risk variants. We constructed a chondrocyte-specific regulatory network by mapping 3D chromatin structure and active enhancers in human chondrocytes. We then intersected these data with our previously collected RNA-seq dataset of chondrocytes responding to fibronectin fragment, a known osteoarthritis trigger. Integration of the 3 genomic datasets with recently reported osteoarthritis genome-wide association study variants revealed a refined set of putative causal osteoarthritis variants and their potential target genes. One of the putative target genes identified was SOCS2, which was connected to a putative causal variant by a 170-kb loop and is differentially regulated in response to fibronectin fragment. CRISPR-Cas9-mediated deletion of SOCS2 in primary human chondrocytes from 3 independent donors led to heightened expression of inflammatory markers after fibronectin fragment treatment. These data suggest that SOCS2 plays a role in resolving inflammation in response to cartilage matrix damage and provides a possible mechanistic explanation for its influence on osteoarthritis risk. In total, we identified 56 unique putative osteoarthritis risk genes for further research and potential therapeutic development.
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Affiliation(s)
- Eliza Thulson
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Eric S Davis
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Susan D’Costa
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Philip R Coryell
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nicole E Kramer
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Karen L Mohlke
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Richard F Loeser
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Division of Rheumatology, Allergy and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Brian O Diekman
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Raleigh, NC 27695, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Douglas H Phanstiel
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Thurston Arthritis Research Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC 27599, USA
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11
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Copp ME, Chubinskaya S, Bracey DN, Shine J, Sessions G, Loeser RF, Diekman BO. Comet assay for quantification of the increased DNA damage burden in primary human chondrocytes with aging and osteoarthritis. Aging Cell 2022; 21:e13698. [PMID: 35996812 PMCID: PMC9470893 DOI: 10.1111/acel.13698] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 07/06/2022] [Accepted: 07/30/2022] [Indexed: 01/25/2023] Open
Abstract
It is known that chondrocytes from joints with osteoarthritis (OA) exhibit high levels of DNA damage, but the degree to which chondrocytes accumulate DNA damage during "normal aging" has not been established. The goal of this study was to quantify the DNA damage present in chondrocytes obtained from cadaveric donors of a wide age range, and to compare the extent of this damage to OA chondrocytes. The alkaline comet assay was used to measure the DNA damage in normal cartilage from the ankle (talus) and the knee (femur) of cadaveric donors, as well as in OA chondrocytes obtained at the time of total knee replacement. Chondrocytes from younger donors (<45 years) had less DNA damage than older donors (>70 years) as assessed by the percentage of DNA in the comet "tail". In donors between 50 and 60 years old, there was increased DNA damage in chondrocytes from OA cartilage as compared to cadaveric. Talar chondrocytes from 23 donors between the ages of 34 and 78 revealed a linear increase in DNA damage with age (R2 = 0.865, p < 0.0001). A "two-tailed" comet assay was used to demonstrate that most of the accumulated damage is in the form of strand breaks as opposed to alkali-labile base damage. Chondrocytes from young donors required 10 Gy irradiation to recapitulate the DNA damage present in chondrocytes from older donors. Given the potential for DNA damage to contribute to chondrocyte dysfunction and senescence, this study supports the investigation of mechanisms by which hypo-replicative cell types accumulate high levels of damage.
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Affiliation(s)
- Michaela E. Copp
- Joint Department of Biomedical EngineeringUniversity of North Carolina at Chapel Hill, Chapel Hill and North Carolina State UniversityRaleighNorth CarolinaUSA,Thurston Arthritis Research CenterUniversity of North Carolina at Chapel HillChapel HillNorth CarolinaUSA,Comparative Medicine InstituteNorth Carolina State UniversityRaleighNorth CarolinaUSA
| | - Susan Chubinskaya
- Department of PediatricsRush University Medical CenterChicagoIllinoisUSA
| | - Daniel N. Bracey
- Department of OrthopaedicsUniversity of North CarolinaChapel HillNorth CarolinaUSA
| | - Jacqueline Shine
- Thurston Arthritis Research CenterUniversity of North Carolina at Chapel HillChapel HillNorth CarolinaUSA
| | - Garrett Sessions
- Thurston Arthritis Research CenterUniversity of North Carolina at Chapel HillChapel HillNorth CarolinaUSA,Department of Cell Biology & PhysiologyUniversity of North CarolinaChapel HillNorth CarolinaUSA
| | - Richard F. Loeser
- Thurston Arthritis Research CenterUniversity of North Carolina at Chapel HillChapel HillNorth CarolinaUSA,Department of Cell Biology & PhysiologyUniversity of North CarolinaChapel HillNorth CarolinaUSA,Division of Rheumatology, Allergy, and ImmunologyUniversity of North CarolinaChapel HillNorth CarolinaUSA
| | - Brian O. Diekman
- Joint Department of Biomedical EngineeringUniversity of North Carolina at Chapel Hill, Chapel Hill and North Carolina State UniversityRaleighNorth CarolinaUSA,Thurston Arthritis Research CenterUniversity of North Carolina at Chapel HillChapel HillNorth CarolinaUSA,Comparative Medicine InstituteNorth Carolina State UniversityRaleighNorth CarolinaUSA
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12
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Novais EJ, Tran VA, Johnston SN, Darris KR, Roupas AJ, Sessions GA, Shapiro IM, Diekman BO, Risbud MV. Long-term treatment with senolytic drugs Dasatinib and Quercetin ameliorates age-dependent intervertebral disc degeneration in mice. Nat Commun 2021; 12:5213. [PMID: 34480023 PMCID: PMC8417260 DOI: 10.1038/s41467-021-25453-2] [Citation(s) in RCA: 133] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 08/04/2021] [Indexed: 02/07/2023] Open
Abstract
Intervertebral disc degeneration is highly prevalent within the elderly population and is a leading cause of chronic back pain and disability. Due to the link between disc degeneration and senescence, we explored the ability of the Dasatinib and Quercetin drug combination (D + Q) to prevent an age-dependent progression of disc degeneration in mice. We treated C57BL/6 mice beginning at 6, 14, and 18 months of age, and analyzed them at 23 months of age. Interestingly, 6- and 14-month D + Q cohorts show lower incidences of degeneration, and the treatment results in a significant decrease in senescence markers p16INK4a, p19ARF, and SASP molecules IL-6 and MMP13. Treatment also preserves cell viability, phenotype, and matrix content. Although transcriptomic analysis shows disc compartment-specific effects of the treatment, cell death and cytokine response pathways are commonly modulated across tissue types. Results suggest that senolytics may provide an attractive strategy to mitigating age-dependent disc degeneration.
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Affiliation(s)
- Emanuel J. Novais
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, USA ,grid.265008.90000 0001 2166 5843Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, USA ,grid.10328.380000 0001 2159 175XLife and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal ,grid.10328.380000 0001 2159 175XICVS/3B’s—PT Government Associate Laboratory, Braga, Portugal
| | - Victoria A. Tran
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, USA
| | - Shira N. Johnston
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, USA ,grid.265008.90000 0001 2166 5843Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, USA
| | - Kayla R. Darris
- grid.10698.360000000122483208Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC USA ,grid.40803.3f0000 0001 2173 6074Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, and North Carolina State University, Raleigh, NC USA
| | - Alex J. Roupas
- grid.10698.360000000122483208Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC USA ,grid.40803.3f0000 0001 2173 6074Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, and North Carolina State University, Raleigh, NC USA
| | - Garrett A. Sessions
- grid.10698.360000000122483208Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC USA ,grid.40803.3f0000 0001 2173 6074Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, and North Carolina State University, Raleigh, NC USA
| | - Irving M. Shapiro
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, USA ,grid.265008.90000 0001 2166 5843Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, USA
| | - Brian O. Diekman
- grid.10698.360000000122483208Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC USA ,grid.40803.3f0000 0001 2173 6074Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, and North Carolina State University, Raleigh, NC USA
| | - Makarand V. Risbud
- grid.265008.90000 0001 2166 5843Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, USA ,grid.265008.90000 0001 2166 5843Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, USA
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13
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Collins JA, Kapustina M, Bolduc JA, Pike JFW, Diekman BO, Mix K, Chubinskaya S, Eroglu E, Michel T, Poole LB, Furdui CM, Loeser RF. Sirtuin 6 (SIRT6) regulates redox homeostasis and signaling events in human articular chondrocytes. Free Radic Biol Med 2021; 166:90-103. [PMID: 33600943 PMCID: PMC8009856 DOI: 10.1016/j.freeradbiomed.2021.01.054] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/29/2021] [Accepted: 01/31/2021] [Indexed: 12/30/2022]
Abstract
The nuclear localized protein deacetylase, SIRT6, has been identified as a crucial regulator of biological processes that drive aging. Among these processes, SIRT6 can promote resistance to oxidative stress conditions, but the precise mechanisms remain unclear. The objectives of this study were to examine the regulation of SIRT6 activity by age and oxidative stress and define the role of SIRT6 in maintaining redox homeostasis in articular chondrocytes. Although SIRT6 levels did not change with age, SIRT6 activity was significantly reduced in chondrocytes isolated from older adults. Using dimedone-based chemical probes that detect oxidized cysteines, we identified that SIRT6 is oxidized in response to oxidative stress conditions, an effect that was associated with reduced SIRT6 activity. Enhancement of SIRT6 activity through adenoviral SIRT6 overexpression specifically increased the basal levels of two antioxidant proteins, peroxiredoxin 1 (Prx1) and sulfiredoxin (Srx) and decreased the levels of an inhibitor of antioxidant activity, thioredoxin interacting protein (TXNIP). Conversely, in chondrocytes derived from mice with cartilage specific Sirt6 knockout, Sirt6 loss decreased Prx1 levels and increased TXNIP levels. SIRT6 overexpression decreased nuclear-generated H2O2 levels and oxidative stress-induced accumulation of nuclear phosphorylated p65. Our data demonstrate that SIRT6 activity is altered with age and oxidative stress conditions associated with aging. SIRT6 contributes to chondrocyte redox homeostasis by regulating specific members of the Prx catalytic cycle. Targeted therapies aimed at preventing the age-related decline in SIRT6 activity may represent a novel strategy to maintain redox balance in joint tissues and decrease catabolic signaling events implicated in osteoarthritis (OA).
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Affiliation(s)
- John A Collins
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Maryna Kapustina
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jesalyn A Bolduc
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Brussels Center for Redox Biology, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussel, Belgium
| | - James F W Pike
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brian O Diekman
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC, USA
| | - Kimberlee Mix
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biological Sciences, Loyola University New Orleans, New Orleans, LA, USA
| | - Susan Chubinskaya
- Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA
| | - Emrah Eroglu
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston MA, USA; Sabanci University, Faculty of Engineering and Natural Sciences, Genetics and Bioengineering Program, Nanotechnology Research and Application Center, Istanbul, Turkey
| | - Thomas Michel
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston MA, USA
| | - Leslie B Poole
- Department of Biochemistry, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Cristina M Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Richard F Loeser
- Division of Rheumatology, Allergy and Immunology and the Thurston Arthritis Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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14
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Loeser RF, Collins JA, Diekman BO, Carlson CS. Reply. Arthritis Rheumatol 2021; 72:2162-2163. [PMID: 33459503 DOI: 10.1002/art.41431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Richard F Loeser
- University of North Carolina School of Medicine, Chapel Hill, NC
| | - John A Collins
- University of North Carolina School of Medicine, Chapel Hill, NC
| | - Brian O Diekman
- North Carolina State University, Raleigh, NC and University of North Carolina School of Medicine, Chapel Hill, NC
| | - Cathy S Carlson
- University of Minnesota College of Veterinary Medicine, St. Paul, MN
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15
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Abstract
The development of osteoarthritis (OA) correlates with a rise in the number of senescent cells in joint tissues, and the senescence-associated secretory phenotype (SASP) has been implicated in cartilage degradation and OA. Age-related mitochondrial dysfunction and associated oxidative stress might induce senescence in joint tissue cells. However, senescence is not the only driver of OA, and the mechanisms by which senescent cells contribute to disease progression are not fully understood. Furthermore, it remains uncertain which joint cells and SASP-factors contribute to the OA phenotype. Research in the field has looked at developing therapeutics (namely senolytics and senomorphics) that eliminate or alter senescent cells to stop disease progression and pathogenesis. A better understanding of how senescence contributes to joint dysfunction may enhance the effectiveness of these approaches and provide relief for patients with OA.
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Affiliation(s)
- Philip R Coryell
- Division of Rheumatology, Allergy, and Immunology, Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian O Diekman
- Division of Rheumatology, Allergy, and Immunology, Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, USA
| | - Richard F Loeser
- Division of Rheumatology, Allergy, and Immunology, Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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16
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Loeser RF, Kelley KL, Armstrong A, Collins JA, Diekman BO, Carlson CS. Deletion of JNK Enhances Senescence in Joint Tissues and Increases the Severity of Age-Related Osteoarthritis in Mice. Arthritis Rheumatol 2020; 72:1679-1688. [PMID: 32418287 DOI: 10.1002/art.41312] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/12/2020] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To determine the role of JNK signaling in the development of osteoarthritis (OA) induced by joint injury or aging in mice. METHODS In the joint injury model, 12-week-old wild-type control, JNK1-/- , JNK2-/- , and JNK1fl/fl JNK2-/- aggecan-CreERT 2 double-knockout mice were subjected to destabilization of the medial meniscus (DMM) (n = 15 mice per group) or sham surgery (n = 9-10 mice per group), and OA was evaluated 8 weeks later. In the aging experiment, wild-type control, JNK1-/- , and JNK2-/- mice (n = 15 per group) were evaluated at 18 months of age. Mouse knee joints were evaluated by scoring articular cartilage structure, toluidine blue staining, osteophytes, and synovial hyperplasia, by histomorphometric analysis, and by immunostaining for the senescence marker p16INK 4a . Production of matrix metalloproteinase 13 (MMP-13) in cartilage explants in response to fibronectin fragments was measured by enzyme-linked immunosorbent assay. RESULTS There were no differences after DMM surgery between the wild-type and the JNK-knockout mouse groups in articular cartilage structure, toluidine blue, or osteophyte scores or in MMP-13 production in explants. All 3 knockout mouse groups had increased subchondral bone thickness and area of cartilage necrosis compared to wild-type mice. Aged JNK-knockout mice had significantly worse articular cartilage structure scores compared to the aged wild-type control mice (mean ± SD 52 ± 24 in JNK1-/- mice and 60 ± 25 in JNK2-/- mice versus 32 ± 18 in controls; P = 0.02 and P = 0.004, respectively). JNK1-/- mice also had higher osteophyte scores. Deletion of JNK resulted in increased expression of p16INK 4a in the synovium and cartilage in older mice. CONCLUSION JNK1 and JNK2 are not required for the development of OA in the mouse DMM model. Deletion of JNK1 or JNK2 is associated with more severe age-related OA and increased cell senescence, suggesting that JNK may act as a negative regulator of senescence in the joint.
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Affiliation(s)
| | | | | | - John A Collins
- University of North Carolina School of Medicine, Chapel Hill
| | - Brian O Diekman
- University of North Carolina School of Medicine, Chapel Hill, and North Carolina State University, Raleigh
| | - Cathy S Carlson
- University of Minnesota College of Veterinary Medicine, St. Paul
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17
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Griffith CM, Huang SA, Cho C, Khare TM, Rich M, Lee GH, Ligler FS, Diekman BO, Polacheck WJ. Microfluidics for the study of mechanotransduction. J Phys D Appl Phys 2020; 53:224004. [PMID: 33840837 PMCID: PMC8034607 DOI: 10.1088/1361-6463/ab78d4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Mechanical forces regulate a diverse set of biological processes at cellular, tissue, and organismal length scales. Investigating the cellular and molecular mechanisms that underlie the conversion of mechanical forces to biological responses is challenged by limitations of traditional animal models and in vitro cell culture, including poor control over applied force and highly artificial cell culture environments. Recent advances in fabrication methods and material processing have enabled the development of microfluidic platforms that provide precise control over the mechanical microenvironment of cultured cells. These devices and systems have proven to be powerful for uncovering and defining mechanisms of mechanotransduction. In this review, we first give an overview of the main mechanotransduction pathways that function at sites of cell adhesion, many of which have been investigated with microfluidics. We then discuss how distinct microfluidic fabrication methods can be harnessed to gain biological insight, with description of both monolithic and replica molding approaches. Finally, we present examples of how microfluidics can be used to apply both solid forces (substrate mechanics, strain, and compression) and fluid forces (luminal, interstitial) to cells. Throughout the review, we emphasize the advantages and disadvantages of different fabrication methods and applications of force in order to provide perspective to investigators looking to apply forces to cells in their own research.
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Affiliation(s)
- Christian M Griffith
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Stephanie A Huang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Crescentia Cho
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Tanmay M Khare
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC
| | - Matthew Rich
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
| | - Gi-Hun Lee
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Frances S Ligler
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Brian O Diekman
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
| | - William J Polacheck
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
- McAllister Heart Institute, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
- Cancer Cell Biology Program, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
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18
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Tessier S, Doolittle AC, Sao K, Rotty JD, Bear JE, Ulici V, Loeser RF, Shapiro IM, Diekman BO, Risbud MV. Arp2/3 inactivation causes intervertebral disc and cartilage degeneration with dysregulated TonEBP-mediated osmoadaptation. JCI Insight 2020; 5:131382. [PMID: 31961823 DOI: 10.1172/jci.insight.131382] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 01/15/2020] [Indexed: 01/01/2023] Open
Abstract
Extracellular matrix and osmolarity influence the development and homeostasis of skeletal tissues through Rho GTPase-mediated alteration of the actin cytoskeleton. This study investigated whether the actin-branching Arp2/3 complex, a downstream effector of the Rho GTPases Cdc42 and Rac1, plays a critical role in maintaining the health of matrix-rich and osmotically loaded intervertebral discs and cartilage. Mice with constitutive intervertebral disc- and cartilage-specific deletion of the critical Arp2/3 subunit Arpc2 (Col2-Cre; Arpc2fl/fl) developed chondrodysplasia and spinal defects. Since these mice did not survive to adulthood, we generated mice with inducible Arpc2 deletion in disc and cartilage (Acan-CreERT2; Arpc2fl/fl). Inactivation of Arp2/3 at skeletal maturity resulted in growth plate closure, loss of proteoglycan content in articular cartilage, and degenerative changes in the intervertebral disc at 1 year of age. Chondrocytes with Arpc2 deletion showed compromised cell spreading on both collagen and fibronectin. Pharmacological inhibition of Cdc42 and Arp2/3 prevented the osmoadaptive transcription factor TonEBP/NFAT5 from recruiting cofactors in response to a hyperosmolarity challenge. Together, these findings suggest that Arp2/3 plays a critical role in cartilaginous tissues through the regulation of cell-extracellular matrix interactions and modulation of TonEBP-mediated osmoadaptation.
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Affiliation(s)
- Steven Tessier
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College
| | - Alexandra C Doolittle
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College.,Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Kimheak Sao
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College.,Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jeremy D Rotty
- Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA.,Department of Cell Biology and Physiology.,UNC Lineberger Comprehensive Cancer Center
| | - James E Bear
- Department of Cell Biology and Physiology.,UNC Lineberger Comprehensive Cancer Center
| | - Veronica Ulici
- Thurston Arthritis Research Center, and.,Division of Rheumatology, Allergy, and Immunology, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Richard F Loeser
- Thurston Arthritis Research Center, and.,Division of Rheumatology, Allergy, and Immunology, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Irving M Shapiro
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College.,Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Brian O Diekman
- Division of Rheumatology, Allergy, and Immunology, Department of Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill and Raleigh, North Carolina, USA
| | - Makarand V Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College.,Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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19
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Abstract
Osteoarthritis (OA) is a highly prevalent disease with limited treatment options. The search for disease-modifying OA therapies would benefit from a more comprehensive knowledge of the genetic variants that contribute to chondrocyte dysfunction and the barriers to cartilage regeneration. One goal of this study was to establish a system for producing engineered cartilage tissue from genetically defined primary human chondrocytes through genome editing and single-cell expansion. This process was utilized to investigate the functional effect of biallelic knockout of the cell cycle inhibitor p21. The use of ribonucleoprotein (RNP) CRISPR/Cas9 complexes targeting two sites in the coding region of p21 resulted in a high frequency (16%) of colonies with homozygous p21 knockout. Chondrogenic pellet cultures from expanded chondrocytes with complete loss of p21 produced more glycosaminoglycans (GAG) and maintained a higher cell number. Single-cell-derived colonies retained the potential for robust matrix production after expansion, allowing for analysis of colony variability from the same population of targeted cells. The effect of enhanced cartilage matrix production in p21 knockout chondrocytes persisted when matrix production from individual colonies was analyzed. Chondrocytes had lower levels of p21 protein with further expansion, and the difference in GAG production with p21 knockout was strongest at early passages. These results support previous findings that implicate p21 as a barrier to cartilage matrix production and regenerative capacity. Furthermore, this work establishes the use of genome-edited human chondrocytes as a promising approach for engineered tissue models containing user-defined gene knockouts and other genetic variants for investigation of OA pathogenesis. Impact Statement This work provides two important advances to the field of tissue engineering. One is the demonstration that engineered cartilage tissue can be produced from genetically defined populations of primary human chondrocytes. While CRISPR/Cas-9 genome editing has been extensively used in cell lines that divide indefinitely, this work extends the technique to an engineered tissue model system to support investigation of genetic changes that affect cartilage production. A second contribution is the finding that chondrocytes with p21 knockout synthesized more cartilage matrix tissue than unedited controls. This supports the continued investigation of p21 as a potential barrier to effective cartilage regeneration.
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Affiliation(s)
- Susan D'Costa
- Thurston Arthritis Research Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Matthew J Rich
- Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina and North Carolina State University, Raleigh, North Carolina
| | - Brian O Diekman
- Thurston Arthritis Research Center, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.,Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina and North Carolina State University, Raleigh, North Carolina.,Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Sessions GA, Copp ME, Liu JY, Sinkler MA, D'Costa S, Diekman BO. Controlled induction and targeted elimination of p16 INK4a-expressing chondrocytes in cartilage explant culture. FASEB J 2019; 33:12364-12373. [PMID: 31408372 DOI: 10.1096/fj.201900815rr] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cellular senescence is a phenotypic state that contributes to age-related diseases through the secretion of matrix-degrading and inflammatory molecules. An emerging therapeutic strategy for osteoarthritis (OA) is to selectively eliminate senescent cells by initiating apoptosis. This study establishes a cartilage explant model of senescence induction and senolytic clearance using p16Ink4a expression as a biomarker of senescence. Growth-factor stimulation of explants increased the expression of p16Ink4a at both the mRNA and protein levels. Applying this culture system to cartilage from p16tdTom reporter mice (a knockin allele with tdTomato fluorescent protein regulated by the endogenous p16Ink4a promoter) demonstrated the emergence of a p16-high population that was quantified using flow cytometry for tdTomato. Cell sorting was used to separate chondrocytes based on tdTomato fluorescence and p16-high cells showed higher senescence-associated β-galactosidase activity and increased gene expression of the senescence-associated secretory phenotype as compared with p16-low cells. The potential for effective senolysis within the cartilage extracellular matrix was assessed using navitoclax (ABT-263). Navitoclax treatment reduced the percentage of p16-high cells from 17.9 to 6.1% (mean of 13 matched pairs; P < 0.001) and increased cleaved caspase-3 confirmed apoptotic activity. Together, these findings establish a physiologically relevant cartilage explant model for testing the induction and elimination of senescent chondrocytes, which will support investigations of senolytic therapy for OA.-Sessions, G. A., Copp, M. E., Liu, J.-Y., Sinkler, M. A., D'Costa, S., Diekman, B. O. Controlled induction and targeted elimination of p16INK4a-expressing chondrocytes in cartilage explant culture.
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Affiliation(s)
- Garrett A Sessions
- Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Michaela E Copp
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina-North Carolina State University, Raleigh, North Carolina, USA
| | - Jie-Yu Liu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Margaret A Sinkler
- Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Susan D'Costa
- Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Brian O Diekman
- Thurston Arthritis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina-North Carolina State University, Raleigh, North Carolina, USA.,Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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21
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Novais EJ, Diekman BO, Shapiro IM, Risbud MV. p16 Ink4a deletion in cells of the intervertebral disc affects their matrix homeostasis and senescence associated secretory phenotype without altering onset of senescence. Matrix Biol 2019; 82:54-70. [PMID: 30811968 DOI: 10.1016/j.matbio.2019.02.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 02/02/2019] [Accepted: 02/22/2019] [Indexed: 12/16/2022]
Abstract
Intervertebral disc degeneration is an important contributor to chronic low back and neck pain. Although many environmental and genetic factors are known to contribute to disc degeneration, age is still the most significant risk factor. Recent studies have shown that senescence may play a role in age-related disc degeneration and matrix catabolism in humans and mouse models. Clearance of p16Ink4a-positive senescent cells reduces the degenerative phenotype in many age-associated diseases. Whether p16Ink4a plays a functional role in intervertebral disc degeneration and senescence is unknown. We first characterized the senescence status of discs in young and old mice. Quantitative histology, gene expression and a novel p16tdTom reporter mice showed an increase in p16Ink4a, p21 and IL-6, with a decrease in Ki67 with aging. Accordingly, we studied the spinal-phenotype of 18-month-old mice with conditional deletion of p16Ink4a in the disc driven by Acan-CreERT2 (cKO). The analyses of discs of cKO and age-matched control mice showed little change in cell morphology and tissue architecture. The cKO mice exhibited changes in functional attributes of aggrecan as well as in collagen composition of the intervertebral disc. While cKO discs exhibited a small decrease in TUNEL positive cells, lineage tracing experiments using ZsGreen reporter indicated that the overall changes in cell fate or numbers were minimal. The cKO mice maintained expression of NP-cell phenotypic markers CA3, Krt19 and GLUT-1. Moreover, in cKO discs, levels of p19Arf and RB were higher without alterations in Ki67, γH2AX, CDK4 and Lipofuscin deposition. Interestingly, the cKO discs showed lower levels of SASP markers, IL-1β, IL-6, MCP1 and TGF-β1. These results show that while, p16Ink4a is dispensable for induction and maintenance of senescence, conditional loss of p16Ink4a reduces apoptosis, limits the SASP phenotype and alters matrix homeostasis of disc cells.
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Affiliation(s)
- Emanuel J Novais
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, USA; Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, USA; Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga, Portugal
| | - Brian O Diekman
- Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA; Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC, USA; North Carolina State University, Raleigh, NC, USA
| | - Irving M Shapiro
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, USA; Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, USA
| | - Makarand V Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, USA; Graduate Program in Cell Biology and Regenerative Medicine, Thomas Jefferson University, Philadelphia, USA.
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Diekman BO, Sessions GA, Collins JA, Knecht AK, Strum SL, Mitin NK, Carlson CS, Loeser RF, Sharpless NE. Expression of p16 INK 4a is a biomarker of chondrocyte aging but does not cause osteoarthritis. Aging Cell 2018; 17:e12771. [PMID: 29744983 PMCID: PMC6052464 DOI: 10.1111/acel.12771] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2018] [Indexed: 12/12/2022] Open
Abstract
Cellular senescence drives a functional decline of numerous tissues with aging by limiting regenerative proliferation and/or by producing pro‐inflammatory molecules known as the senescence‐associated secretory phenotype (SASP). The senescence biomarker p16INK4a is a potent inhibitor of the cell cycle but is not essential for SASP production. Thus, it is unclear whether p16INK4a identifies senescence in hyporeplicative cells such as articular chondrocytes and whether p16INK4a contributes to pathologic characteristics of cartilage aging. To address these questions, we examined the role of p16INK4a in murine and human models of chondrocyte aging. We observed that p16INK4amRNA expression was significantly upregulated with chronological aging in murine cartilage (~50‐fold from 4 to 18 months of age) and in primary human chondrocytes from 57 cadaveric donors (r2 = .27, p < .0001). Human chondrocytes exhibited substantial replicative potential in vitro that depended on the activity of cyclin‐dependent kinases 4 or 6 (CDK4/6), and proliferation was reduced in cells from older donors with increased p16INK4a expression. Moreover, increased chondrocyte p16INK4a expression correlated with several SASP transcripts. Despite the relationship between p16INK4a expression and these features of senescence, somatic inactivation of p16INK4a in chondrocytes of adult mice did not mitigate SASP expression and did not alter the rate of osteoarthritis (OA) with physiological aging or after destabilization of the medial meniscus. These results establish that p16INK4a expression is a biomarker of dysfunctional chondrocytes, but that the effects of chondrocyte senescence on OA are more likely driven by production of SASP molecules than by loss of chondrocyte replicative function.
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Affiliation(s)
- Brian O. Diekman
- Lineberger Comprehensive Cancer Center; University of North Carolina School of Medicine; Chapel Hill North Carolina
- Thurston Arthritis Research Center; University of North Carolina School of Medicine; Chapel Hill North Carolina
- Department of Biomedical Engineering; University of North Carolina, Chapel Hill, NC; North Carolina State University; Raleigh North Carolina
| | - Garrett A. Sessions
- Thurston Arthritis Research Center; University of North Carolina School of Medicine; Chapel Hill North Carolina
| | - John A. Collins
- Thurston Arthritis Research Center; University of North Carolina School of Medicine; Chapel Hill North Carolina
| | - Anne K. Knecht
- HealthSpan Diagnostics LLC; Research Triangle Park North Carolina
| | - Susan L. Strum
- HealthSpan Diagnostics LLC; Research Triangle Park North Carolina
| | - Natalia K. Mitin
- HealthSpan Diagnostics LLC; Research Triangle Park North Carolina
| | - Cathy S. Carlson
- Department of Veterinary Clinical Sciences; University of Minnesota; St. Paul Minnesota
| | - Richard F. Loeser
- Thurston Arthritis Research Center; University of North Carolina School of Medicine; Chapel Hill North Carolina
- Division of Rheumatology, Allergy, and Immunology; University of North Carolina School of Medicine; Chapel Hill North Carolina
| | - Norman E. Sharpless
- Lineberger Comprehensive Cancer Center; University of North Carolina School of Medicine; Chapel Hill North Carolina
- Departments of Medicine and Genetics; University of North Carolina School of Medicine; Chapel Hill North Carolina
- The National Cancer Institute; Bethesda Maryland
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Abstract
Ageing-associated changes that affect articular tissues promote the development of osteoarthritis (OA). Although ageing and OA are closely linked, they are independent processes. Several potential mechanisms by which ageing contributes to OA have been elucidated. This Review focuses on the contributions of the following factors: age-related inflammation (also referred to as 'inflammaging'); cellular senescence (including the senescence-associated secretory phenotype (SASP)); mitochondrial dysfunction and oxidative stress; dysfunction in energy metabolism due to reduced activity of 5'-AMP-activated protein kinase (AMPK), which is associated with reduced autophagy; and alterations in cell signalling due to age-related changes in the extracellular matrix. These various processes contribute to the development of OA by promoting a proinflammatory, catabolic state accompanied by increased susceptibility to cell death that together lead to increased joint tissue destruction and defective repair of damaged matrix. The majority of studies to date have focused on articular cartilage, and it will be important to determine whether similar mechanisms occur in other joint tissues. Improved understanding of ageing-related mechanisms that promote OA could lead to the discovery of new targets for therapies that aim to slow or stop the progression of this chronic and disabling condition.
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Affiliation(s)
- Richard F Loeser
- Thurston Arthritis Research Center, Division of Rheumatology, Allergy, and Immunology, 3300 Thurston Building, Campus Box 7280, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7280, USA
| | - John A Collins
- Thurston Arthritis Research Center, Division of Rheumatology, Allergy, and Immunology, 3300 Thurston Building, Campus Box 7280, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7280, USA
| | - Brian O Diekman
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 450 West Drive, Campus Box 7295, Chapel Hill, North Carolina 27599-7295, USA
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24
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Diekman BO, Thakore PI, O'Connor SK, Willard VP, Brunger JM, Christoforou N, Leong KW, Gersbach CA, Guilak F. Knockdown of the cell cycle inhibitor p21 enhances cartilage formation by induced pluripotent stem cells. Tissue Eng Part A 2015; 21:1261-74. [PMID: 25517798 PMCID: PMC4394871 DOI: 10.1089/ten.tea.2014.0240] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 12/02/2014] [Indexed: 01/22/2023] Open
Abstract
The limited regenerative capacity of articular cartilage contributes to progressive joint dysfunction associated with cartilage injury or osteoarthritis. Cartilage tissue engineering seeks to provide a biological substitute for repairing damaged or diseased cartilage, but requires a cell source with the capacity for extensive expansion without loss of chondrogenic potential. In this study, we hypothesized that decreased expression of the cell cycle inhibitor p21 would enhance the proliferative and chondrogenic potential of differentiated induced pluripotent stem cells (iPSCs). Murine iPSCs were directed to differentiate toward the chondrogenic lineage with an established protocol and then engineered to express a short hairpin RNA (shRNA) to reduce the expression of p21. Cells expressing the p21 shRNA demonstrated higher proliferative potential during monolayer expansion and increased synthesis of glycosaminoglycans (GAGs) in pellet cultures. Furthermore, these cells could be expanded ∼150-fold over three additional passages without a reduction in the subsequent production of GAGs, while control cells showed reduced potential for GAG synthesis with three additional passages. In pellets from extensively passaged cells, knockdown of p21 attenuated the sharp decrease in cell number that occurred in control cells, and immunohistochemical analysis showed that p21 knockdown limited the production of type I and type X collagen while maintaining synthesis of cartilage-specific type II collagen. These findings suggest that manipulating the cell cycle can augment the monolayer expansion and preserve the chondrogenic capacity of differentiated iPSCs, providing a strategy for enhancing iPSC-based cartilage tissue engineering.
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Affiliation(s)
- Brian O. Diekman
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina
| | | | - Shannon K. O'Connor
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Vincent P. Willard
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina
| | - Jonathan M. Brunger
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Nicolas Christoforou
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- Department of Biomedical Engineering, Khalifa University of Science, Technology and Research, Abu Dhabi, United Arab Emirates
| | - Kam W. Leong
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | - Charles A. Gersbach
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina
| | - Farshid Guilak
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, North Carolina
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
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Willard VP, Diekman BO, Sanchez-Adams J, Christoforou N, Leong KW, Guilak F. Use of cartilage derived from murine induced pluripotent stem cells for osteoarthritis drug screening. Arthritis Rheumatol 2015; 66:3062-72. [PMID: 25047145 DOI: 10.1002/art.38780] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 07/08/2014] [Indexed: 01/10/2023]
Abstract
OBJECTIVE The discovery of novel disease-modifying drugs for osteoarthritis (OA) is limited by the lack of adequate genetically defined cartilage tissues for application in high-throughput screening systems. We addressed this need by synthesizing cartilage from induced pluripotent stem cells (iPSCs) to establish and validate an in vitro model of OA. METHODS Native or iPSC-derived mouse cartilage samples were treated with the cytokine interleukin-1α (IL-1α) for 3 days to model the inflammatory environment of OA. The biochemical content, mechanical properties, and gene expression of the resulting tissues were assayed. In addition, the inflammatory and catabolic environment of the media was assessed. To establish high-throughput capability, we used a 96-well plate format and conducted a screen of previously identified candidate OA drugs. Glycosaminoglycan (GAG) release into the medium was used as the primary output for screening. RESULTS Treatment of iPSC-derived or native cartilage with IL-1α induced characteristic features of OA in a rapid and dose-dependent manner. In addition to the loss of GAGs and tissue mechanical properties, IL-1α treatment induced the expression of matrix metalloproteinases and increased the production of the inflammatory mediators nitric oxide and prostaglandin E2 . In the high-throughput screen validation, all candidate OA therapeutic agents provided some benefit, but only the NF-κB inhibitor SC514 effectively reduced cartilage loss in response to IL-1α. CONCLUSION This work demonstrates the utility of iPSCs for studying cartilage pathology and provides a platform for identifying novel, patient-specific therapeutic agents that prevent cartilage degradation and modify the course of OA development.
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Wu CL, Diekman BO, Jain D, Guilak F. Diet-induced obesity alters the differentiation potential of stem cells isolated from bone marrow, adipose tissue and infrapatellar fat pad: the effects of free fatty acids. Int J Obes (Lond) 2012; 37:1079-87. [PMID: 23164698 PMCID: PMC3582830 DOI: 10.1038/ijo.2012.171] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 08/30/2012] [Accepted: 09/09/2012] [Indexed: 02/06/2023]
Abstract
Introduction Obesity is a major risk factor for several musculoskeletal conditions that are characterized by an imbalance of tissue remodeling. Adult stem cells are closely associated with the remodeling and potential repair of several mesodermally derived tissues such as fat, bone, and cartilage. We hypothesized that obesity would alter the frequency, proliferation, multipotency, and immunophenotype of adult stem cells from a variety of tissues. Materials and Methods Bone marrow-derived mesenchymal stem cells (MSCs), subcutaneous adipose-derived stem cells (sqASCs), and infrapatellar fat pad-derived stem cells (IFP cells) were isolated from lean and high-fat diet induced obese mice, and their cellular properties were examined. To test the hypothesis that changes in stem cell properties were due to the increased systemic levels of free fatty acids (FFAs), we further investigated the effects of FFAs on lean stem cells in vitro. Results Obese mice showed a trend toward increased prevalence of MSCs and sqASCs in the stromal tissues. While no significant differences in cell proliferation were observed in vitro, the differentiation potential of all types of stem cells was altered by obesity. MSCs from obese mice demonstrated decreased adipogenic, osteogenic, and chondrogenic potential. Obese sqASCs and IFP cells showed increased adipogenic and osteogenic differentiation, but decreased chondrogenic ability. Obese MSCs also showed decreased CD105 and increased PDGFRα expression, consistent with decreased chondrogenic potential. FFA treatment of lean stem cells significantly altered their multipotency but did not completely recapitulate the properties of obese stem cells. Conclusions These findings support the hypothesis that obesity alters the properties of adult stem cells in a manner that depends on the cell source. These effects may be regulated in part by increased levels of FFAs, but may involve other obesity-associated cytokines. These findings contribute to our understanding of mesenchymal tissue remodeling with obesity, as well as the development of autologous stem cell therapies for obese patients.
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Affiliation(s)
- C-L Wu
- Departments of Orthopaedic Surgery and Biomedical Engineering, Duke University Medical Center, Durham, NC, USA
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Diekman BO, Wu CL, Louer CR, Furman BD, Huebner JL, Kraus VB, Olson SA, Guilak F. Intra-articular delivery of purified mesenchymal stem cells from C57BL/6 or MRL/MpJ superhealer mice prevents posttraumatic arthritis. Cell Transplant 2012; 22:1395-408. [PMID: 22889498 DOI: 10.3727/096368912x653264] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Joint injury dramatically enhances the onset of osteoarthritis (OA) and is responsible for an estimated 12% of OA. Posttraumatic arthritis (PTA) is especially common after intra-articular fracture, and no disease-modifying therapies are currently available. We hypothesized that the delivery of mesenchymal stem cells (MSCs) would prevent PTA by altering the balance of inflammation and regeneration after fracture of the mouse knee. Additionally, we examined the hypothesis that MSCs from the MRL/MpJ (MRL) "superhealer" mouse strain would show increased multilineage and therapeutic potentials as compared to those from C57BL/6 (B6) mice, as MRL mice have shown exceptional in vivo regenerative abilities. A highly purified population of MSCs was prospectively isolated from bone marrow using cell surface markers (CD45-/TER119-/PDGFRα+/Sca-1+). B6 MSCs expanded greater than 100,000-fold in 3 weeks when cultured at 2% oxygen and displayed greater adipogenic, osteogenic, and chondrogenic differentiation as compared to MRL MSCs. Mice receiving only a control saline injection after fracture demonstrated PTA after 8 weeks, but the delivery of 10,000 B6 or MRL MSCs to the joint prevented the development of PTA. Cytokine levels in serum and synovial fluid were affected by treatment with stem cells, including elevated systemic interleukin-10 at several time points. The delivery of MSCs did not reduce the degree of synovial inflammation but did show increased bone volume during repair. This study provides evidence that intra-articular stem cell therapy can prevent the development of PTA after fracture and has implications for possible clinical interventions after joint injury before evidence of significant OA.
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Affiliation(s)
- Brian O Diekman
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, USA
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Diekman BO, Rowland CR, Lennon DP, Caplan AI, Guilak F. Chondrogenesis of adult stem cells from adipose tissue and bone marrow: induction by growth factors and cartilage-derived matrix. Tissue Eng Part A 2010; 16:523-33. [PMID: 19715387 DOI: 10.1089/ten.tea.2009.0398] [Citation(s) in RCA: 198] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES Adipose-derived stem cells (ASCs) and bone marrow-derived mesenchymal stem cells (MSCs) are multipotent adult stem cells with potential for use in cartilage tissue engineering. We hypothesized that these cells show distinct responses to different chondrogenic culture conditions and extracellular matrices, illustrating important differences between cell types. METHODS Human ASCs and MSCs were chondrogenically differentiated in alginate beads or a novel scaffold of reconstituted native cartilage-derived matrix with a range of growth factors, including dexamethasone, transforming growth factor beta3, and bone morphogenetic protein 6. Constructs were analyzed for gene expression and matrix synthesis. RESULTS Chondrogenic growth factors induced a chondrocytic phenotype in both ASCs and MSCs in alginate beads or cartilage-derived matrix. MSCs demonstrated enhanced type II collagen gene expression and matrix synthesis as well as a greater propensity for the hypertrophic chondrocyte phenotype. ASCs had higher upregulation of aggrecan gene expression in response to bone morphogenetic protein 6 (857-fold), while MSCs responded more favorably to transforming growth factor beta3 (573-fold increase). CONCLUSIONS ASCs and MSCs are distinct cell types as illustrated by their unique responses to growth factor-based chondrogenic induction. This chondrogenic induction is affected by the composition of the scaffold and the presence of serum.
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Affiliation(s)
- Brian O Diekman
- Departments of Surgery and Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27710, USA
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Fermor B, Gurumurthy A, Diekman BO. Hypoxia, RONS and energy metabolism in articular cartilage. Osteoarthritis Cartilage 2010; 18:1167-73. [PMID: 20633670 PMCID: PMC2929267 DOI: 10.1016/j.joca.2010.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 06/08/2010] [Accepted: 06/09/2010] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Increased pro-inflammatory cytokines and reactive oxygen and nitrogen species (RONS) occur in osteoarthritis (OA). Oxygen tension can alter the levels of RONS induced by interleukin-1 (IL-1). RONS such as nitric oxide (NO) can alter energy metabolism. The aim of this study was to determine if oxygen tension alters energy metabolism, in articular cartilage, in response to IL-1 or NO and to determine if cell death occurred. DESIGN Porcine articular chondrocytes were incubated with IL-1 or the NO donor NOC-18 for 48 h in either 1, 5 or 20% O(2). Adenosine triphosphate (ATP) levels were measured and immunoblots for adenosine monophosphate-activated protein kinase (AMPK) were done. Protein translation was measured by S6 activation. Senescence and autophagy were determined by increased caveolin or conversion of LC3-I to LC3-II respectively. RESULTS One percent O(2) significantly reduced ATP levels compared with 20% O(2). Five percent O(2) significantly increased ATP levels compared with 20% O(2). One percent O(2) significantly increased phospho-AMPK (pAMPK) protein expression compared with 5 or 20% O(2). Oxygen tension had no effects on pS6, caveolin or LC3-II levels. IL-1-induced NO production was significantly reduced with decreased oxygen tension, and significantly reduced ATP levels at all oxygen tensions, but pAMPK was only significantly increased at 5% O(2). IL-1 significantly reduced pS6 at all oxygen tensions. IL-1 had no effects on caveolin and significantly increased LC3-II at 20% O(2) only. NOC-18 significantly reduced ATP levels at all oxygen tensions, and significantly increased pAMPK at 5% O(2) only, and significantly decreased pAMPK at 1% O(2). NOC-18 significantly reduced pS6 at 1% O(2) and significantly increased caveolin at 5% O(2), and LC3-II at 1% O(2). CONCLUSION Our data suggest 5% O(2) is optimal for energy metabolism and protective to some effects of IL-1 and NO. NO has the greatest effects on ATP levels and the induction of autophagy at 1% O(2).
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Diekman BO, Estes BT, Guilak F. The effects of BMP6 overexpression on adipose stem cell chondrogenesis: Interactions with dexamethasone and exogenous growth factors. J Biomed Mater Res A 2010; 93:994-1003. [PMID: 19722282 DOI: 10.1002/jbm.a.32589] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Adipose-derived stem cells (ASCs) are multipotent progenitors that can be chondrogenically induced by growth factors such as bone morphogenetic protein 6 (BMP-6). We hypothesized that nonviral transfection of a BMP-6 construct (pcDNA3-BMP6) would induce chondrogenic differentiation of ASCs encapsulated in alginate beads and that differentiation would be enhanced by the presence of the synthetic glucocorticoid dexamethasone (DEX) or the combination of epidermal growth factor (EGF), fibroblast growth factor-2 (FGF-2), and transforming growth factor beta-1 (TGF-beta1), collectively termed expansion factors (EFs). Chondrogenesis was assessed using quantitative real-time polymerase chain reaction for types I, II, and X collagen, aggrecan, and BMP6. Immunohistochemistry was performed with antibodies for types I, II, and X collagen and chondroitin-4-sulfate. BMP6 overexpression alone induced a moderate chondrogenic response. The inclusion of EFs promoted robust type II collagen expression but also increased type I and X collagen deposition, consistent with a hypertrophic chondrocyte phenotype. Early gene expression data indicated that DEX was synergistic with BMP-6 for chondrogenesis, but immunohistochemistry at 28 days showed that DEX reduced glycosaminoglycan accumulation. These results suggest that chondrogenic differentiation of ASCs depends on complex interactions among various growth factors and media supplements, as well as the concentration and duration of growth factor exposure.
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Affiliation(s)
- Brian O Diekman
- Orthopaedic Research Laboratories, Department of Surgery, Division of Orthopaedic Surgery, 375 MSRB, Box 3093, Duke University Medical Center, Durham, North Carolina 27710, USA
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Abstract
The ability to isolate, expand and differentiate adult stem cells into a chondrogenic lineage is an important step in the development of tissue engineering approaches for cartilage repair or regeneration for the treatment of joint injury or osteoarthritis, as well as for their application in plastic or reconstructive surgery. Adipose-derived stem cells (ASCs) provide an abundant and easily accessible source of adult stem cells for use in such regenerative approaches. This protocol first describes the isolation of ASCs from liposuction aspirate. The cell culture conditions provided for ASC expansion provide a large number of multipotent stem cells. Instructions for growth factor-based induction of ASCs into chondrocyte-like cells using either cell pellet or alginate bead systems are detailed. These methods are similar to those published for chondrogenesis of bone marrow-derived mesenchymal stem cells but distinct because of the unique nature of ASCs. Investigators can expect consistent differentiation of ASCs, allowing for slight variation as a result of donor and serum lot effects. Approximately 10-12 weeks are needed for the entire process of ASC isolation, including the characterization of chondrocyte-like cells, which is also described.
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Affiliation(s)
- Bradley T Estes
- Departments of Surgery and Biomedical Engineering, Duke University Medical Center, Durham, North Carolina, USA
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Valonen PK, Moutos FT, Kusanagi A, Moretti MG, Diekman BO, Welter JF, Caplan AI, Guilak F, Freed LE. In vitro generation of mechanically functional cartilage grafts based on adult human stem cells and 3D-woven poly(epsilon-caprolactone) scaffolds. Biomaterials 2010; 31:2193-200. [PMID: 20034665 DOI: 10.1016/j.biomaterials.2009.11.092] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 11/25/2009] [Indexed: 12/12/2022]
Abstract
Three-dimensionally woven poly(epsilon-caprolactone) (PCL) scaffolds were combined with adult human mesenchymal stem cells (hMSC) to engineer mechanically functional cartilage constructs in vitro. The specific objectives were to: (i) produce PCL scaffolds with cartilage-like mechanical properties, (ii) demonstrate that hMSCs formed cartilage after 21 days of culture on PCL scaffolds, and (iii) study effects of scaffold structure (loosely vs. tightly woven), culture vessel (static dish vs. oscillating bioreactor), and medium composition (chondrogenic additives with or without serum). Aggregate moduli of 21-day constructs approached normal articular cartilage for tightly woven PCL cultured in bioreactors, were lower for tightly woven PCL cultured statically, and lowest for loosely woven PCL cultured statically (p<0.05). Construct DNA, total collagen, and glycosaminoglycans (GAG) increased in a manner dependent on time, culture vessel, and medium composition. Chondrogenesis was verified histologically by rounded cells within a hyaline-like matrix that immunostained for collagen type II but not type I. Bioreactors yielded constructs with higher collagen content (p<0.05) and more homogenous matrix than static controls. Chondrogenic additives yielded constructs with higher GAG (p<0.05) and earlier expression of collagen II mRNA if serum was not present in medium. These results show feasibility of functional cartilage tissue engineering from hMSC and 3D-woven PCL scaffolds.
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Affiliation(s)
- Piia K Valonen
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Estes BT, Diekman BO, Guilak F. Monolayer cell expansion conditions affect the chondrogenic potential of adipose-derived stem cells. Biotechnol Bioeng 2008; 99:986-95. [PMID: 17929321 DOI: 10.1002/bit.21662] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Adipose-derived stem cells (ASCs) are an abundant, readily available population of multipotent progenitor cells that reside in adipose tissue. Isolated ASCs are typically expanded in monolayer on standard tissue culture plastic with a basal medium containing 10% fetal bovine serum. However, recent data suggest that altering the monolayer expansion conditions by using suspension culture plastic, adding growth factors to the medium, or adjusting the seeding density may affect the self-renewal rate, multipotency, and lineage-specific differentiation potential of the ASCs. We hypothesized that variation in any of these expansion conditions would influence the chondrogenic potential of ASCs. ASCs were isolated from human liposuction waste tissue and expanded through two passages with different tissue culture plastic, feed medium, and cell seeding densities. Once expanded, the cells were cast in an agarose gel and subjected to identical chondrogenic culture conditions for 7 days, at which point cell viability, radiolabel incorporation, and gene expression were measured. High rates of matrix synthesis upon chondrogenic induction were mostly associated with smaller cells, as indicated by cell width and area on tissue culture plastic, and it appears that expansion in a growth factor supplemented medium is important in maintaining this morphology. All end-point measures were highly dependent on the specific monolayer culture conditions. These results support the hypothesis that monolayer culture conditions may "prime" the cells or predispose them towards a specific phenotype and thus underscore the importance of early culture conditions in determining the growth and differentiation potential of ASCs.
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Affiliation(s)
- Bradley T Estes
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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