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Saul D, Doolittle ML, Rowsey JL, Froemming MN, Kosinsky RL, Vos SJ, Ruan M, LeBrasseur NK, Chandra A, Pignolo RJ, Passos JF, Farr JN, Monroe DG, Khosla S. Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair. J Clin Invest 2024:e179834. [PMID: 38753433 DOI: 10.1172/jci179834] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024] Open
Abstract
Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21+ cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21+ cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21+ cell clearance did not alter bone loss due to aging; conversely, p16+ cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21+ neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21+ OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell-like OCH subset that was p21+ and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells were key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings established contextual roles of p21+ vs p16+ senescent/senescent-like cells that may be leveraged for therapeutic opportunities.
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Affiliation(s)
- Dominik Saul
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
| | | | - Jennifer L Rowsey
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
| | | | - Robyn L Kosinsky
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, United States of America
| | - Stephanie J Vos
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
| | - Ming Ruan
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
| | - Nathan K LeBrasseur
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States of America
| | - Abhishek Chandra
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States of America
| | - Robert J Pignolo
- Division of Endocrinology, Mayo Cinic, Rochester, United States of America
| | - João F Passos
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States of America
| | - Joshua N Farr
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
| | - David G Monroe
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
| | - Sundeep Khosla
- Division of Endocrinology, Mayo Clinic, Rochester, United States of America
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Saul D, Doolittle ML, Rowsey JL, Froemming MN, Kosinsky RL, Vos SJ, Ruan M, LeBrasseur N, Chandra A, Pignolo R, Passos JF, Farr JN, Monroe DG, Khosla S. Osteochondroprogenitor cells and neutrophils expressing p21 and senescence markers modulate fracture repair. bioRxiv 2024:2024.02.01.578420. [PMID: 38370844 PMCID: PMC10871229 DOI: 10.1101/2024.02.01.578420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2024]
Abstract
Cells expressing features of senescence, including upregulation of p21 and p16, appear transiently following tissue injury, yet the properties of these cells or how they contrast with age-induced senescent cells remains unclear. Here, we used skeletal injury as a model and identified the rapid appearance following fracture of p21+ cells expressing senescence markers, mainly as osteochondroprogenitors (OCHs) and neutrophils. Targeted genetic clearance of p21+ cells suppressed senescence-associated signatures within the fracture callus and accelerated fracture healing. By contrast, p21+ cell clearance did not alter bone loss due to aging; conversely, p16+ cell clearance, known to alleviate skeletal aging, did not affect fracture healing. Following fracture, p21+ neutrophils were enriched in signaling pathways known to induce paracrine stromal senescence, while p21+ OCHs were highly enriched in senescence-associated secretory phenotype factors known to impair bone formation. Further analysis revealed an injury-specific stem cell-like OCH subset that was p21+ and highly inflammatory, with a similar inflammatory mesenchymal population (fibro-adipogenic progenitors) evident following muscle injury. Thus, intercommunicating senescent-like neutrophils and mesenchymal progenitor cells are key regulators of tissue repair in bone and potentially across tissues. Moreover, our findings establish contextual roles of p21+ vs p16+ senescent/senescent-like cells that may be leveraged for therapeutic opportunities.
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Doolittle ML, Eckhardt BA, Vos SJ, Grain S, Rowsey JL, Ruan M, Saul D, Farr JN, Weivoda MM, Khosla S, Monroe DG. Modest Effects of Osteoclast-Specific ERα Deletion after Skeletal Maturity. JBMR Plus 2023; 7:e10797. [PMID: 37808391 PMCID: PMC10556268 DOI: 10.1002/jbm4.10797] [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] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/15/2023] [Accepted: 06/28/2023] [Indexed: 10/10/2023] Open
Abstract
Estrogen regulates bone mass in women and men, but the underlying cellular mechanisms of estrogen action on bone remain unclear. Although both estrogen receptor (ER)α and ERβ are expressed in bone cells, ERα is the dominant receptor for skeletal estrogen action. Previous studies using either global or cell-specific ERα deletion provided important insights, but each of these approaches had limitations. Specifically, either high circulating sex steroid levels in global ERα knockout mice or the effects of deletion of ERα during growth and development in constitutive cell-specific knockout mice have made it difficult to clearly define the role of ERα in specific cell types in the adult skeleton. We recently generated and characterized mice with tamoxifen-inducible ERα deletion in osteocytes driven by the 8-kb Dmp1 promoter (ERαΔOcy mice), revealing detrimental effects of osteocyte-specific ERα deletion on trabecular bone volume (-20.1%) and bone formation rate (-18.9%) in female, but not male, mice. Here, we developed and characterized analogous mice with inducible ERα deletion in osteoclasts using the Cathepsin K promoter (ERαΔOcl mice). In a study design identical to that with the previously described ERαΔOcy mice, adult female, but not male, ERαΔOcl mice showed a borderline (-10.2%, p = 0.084) reduction in trabecular bone volume, no change in osteoclast numbers, but a significant increase in serum CTx levels, consistent with increased osteoclast activity. These findings in ERαΔOcl mice differ from previous studies of constitutive osteoclast-specific ERα deletion, which led to clear deficits in trabecular bone and increased osteoclast numbers. Collectively, these data indicate that in adult mice, estrogen action in the osteocyte is likely more important than via the osteoclast and that ERα deletion in osteoclasts from conception onward has more dramatic skeletal effects than inducible osteoclastic ERα deletion in adult mice. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Madison L. Doolittle
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Brittany A. Eckhardt
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Stephanie J. Vos
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Sarah Grain
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Jennifer L. Rowsey
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Ming Ruan
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Dominik Saul
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
- Department of Trauma and Reconstructive SurgeryEberhard Karls University Tübingen, BG Trauma Center TübingenTübingenGermany
| | - Joshua N. Farr
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Megan M. Weivoda
- Robert and Arlene Kogod Center on Aging and Division of HematologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
| | - David G. Monroe
- Robert and Arlene Kogod Center on Aging and Division of EndocrinologyMayo Clinic College of MedicineRochesterMinnesotaUSA
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Doolittle ML, Saul D, Kaur J, Rowsey JL, Vos SJ, Pavelko KD, Farr JN, Monroe DG, Khosla S. Multiparametric senescent cell phenotyping reveals targets of senolytic therapy in the aged murine skeleton. Nat Commun 2023; 14:4587. [PMID: 37524694 PMCID: PMC10390564 DOI: 10.1038/s41467-023-40393-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [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: 01/03/2023] [Accepted: 07/26/2023] [Indexed: 08/02/2023] Open
Abstract
Senescence drives organismal aging, yet the deep characterization of senescent cells in vivo remains incomplete. Here, we apply mass cytometry by time-of-flight using carefully validated antibodies to analyze senescent cells at single-cell resolution. We use multiple criteria to identify senescent mesenchymal cells that are growth-arrested and resistant to apoptosis. These p16 + Ki67-BCL-2+ cells are highly enriched for senescence-associated secretory phenotype and DNA damage markers, are strongly associated with age, and their percentages are increased in late osteoblasts/osteocytes and CD24high osteolineage cells. Moreover, both late osteoblasts/osteocytes and CD24high osteolineage cells are robustly cleared by genetic and pharmacologic senolytic therapies in aged mice. Following isolation, CD24+ skeletal cells exhibit growth arrest, senescence-associated β-galactosidase positivity, and impaired osteogenesis in vitro. These studies thus provide an approach using multiplexed protein profiling to define senescent mesenchymal cells in vivo and identify specific skeletal cell populations cleared by senolytics.
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Affiliation(s)
- Madison L Doolittle
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
| | - Dominik Saul
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
- Department for Trauma and Reconstructive Surgery, BG Clinic, University of Tübingen, Tübingen, Germany
| | - Japneet Kaur
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jennifer L Rowsey
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
| | - Stephanie J Vos
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
| | - Kevin D Pavelko
- Department of Immunology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Joshua N Farr
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
| | - David G Monroe
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA
| | - Sundeep Khosla
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA.
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA.
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Farr JN, Saul D, Doolittle ML, Kaur J, Rowsey JL, Vos SJ, Froemming MN, Lagnado AB, Zhu Y, Weivoda M, Ikeno Y, Pignolo RJ, Niedernhofer LJ, Robbins PD, Jurk D, Passos JF, LeBrasseur NK, Tchkonia T, Kirkland JL, Monroe DG, Khosla S. Local senolysis in aged mice only partially replicates the benefits of systemic senolysis. J Clin Invest 2023; 133:e162519. [PMID: 36809340 PMCID: PMC10104901 DOI: 10.1172/jci162519] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [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: 06/13/2022] [Accepted: 02/16/2023] [Indexed: 02/23/2023] Open
Abstract
Clearance of senescent cells (SnCs) can prevent several age-related pathologies, including bone loss. However, the local versus systemic roles of SnCs in mediating tissue dysfunction remain unclear. Thus, we developed a mouse model (p16-LOX-ATTAC) that allowed for inducible SnC elimination (senolysis) in a cell-specific manner and compared the effects of local versus systemic senolysis during aging using bone as a prototype tissue. Specific removal of Sn osteocytes prevented age-related bone loss at the spine, but not the femur, by improving bone formation without affecting osteoclasts or marrow adipocytes. By contrast, systemic senolysis prevented bone loss at the spine and femur and not only improved bone formation, but also reduced osteoclast and marrow adipocyte numbers. Transplantation of SnCs into the peritoneal cavity of young mice caused bone loss and also induced senescence in distant host osteocytes. Collectively, our findings provide proof-of-concept evidence that local senolysis has health benefits in the context of aging, but, importantly, that local senolysis only partially replicates the benefits of systemic senolysis. Furthermore, we establish that SnCs, through their senescence-associated secretory phenotype (SASP), lead to senescence in distant cells. Therefore, our study indicates that optimizing senolytic drugs may require systemic instead of local SnC targeting to extend healthy aging.
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Affiliation(s)
- Joshua N. Farr
- Robert and Arlene Kogod Center on Aging
- Division of Endocrinology
- Department of Physiology and Biomedical Engineering, and
| | - Dominik Saul
- Robert and Arlene Kogod Center on Aging
- Division of Endocrinology
| | | | - Japneet Kaur
- Robert and Arlene Kogod Center on Aging
- Division of Endocrinology
| | | | - Stephanie J. Vos
- Robert and Arlene Kogod Center on Aging
- Division of Endocrinology
| | | | - Anthony B. Lagnado
- Robert and Arlene Kogod Center on Aging
- Department of Physiology and Biomedical Engineering, and
| | - Yi Zhu
- Robert and Arlene Kogod Center on Aging
- Department of Physiology and Biomedical Engineering, and
| | - Megan Weivoda
- Department of Hematology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Yuji Ikeno
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Robert J. Pignolo
- Robert and Arlene Kogod Center on Aging
- Department of Physiology and Biomedical Engineering, and
- Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Laura J. Niedernhofer
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Paul D. Robbins
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Diana Jurk
- Robert and Arlene Kogod Center on Aging
- Department of Physiology and Biomedical Engineering, and
| | - João F. Passos
- Robert and Arlene Kogod Center on Aging
- Department of Physiology and Biomedical Engineering, and
| | - Nathan K. LeBrasseur
- Robert and Arlene Kogod Center on Aging
- Department of Physiology and Biomedical Engineering, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | | | | | - David G. Monroe
- Robert and Arlene Kogod Center on Aging
- Division of Endocrinology
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging
- Division of Endocrinology
- Department of Physiology and Biomedical Engineering, and
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Doolittle ML, Saul D, Kaur J, Rowsey JL, Vos SJ, Pavelko KD, Farr JN, Monroe DG, Khosla S. Multiparametric senescent cell phenotyping reveals CD24 osteolineage cells as targets of senolytic therapy in the aged murine skeleton. bioRxiv 2023:2023.01.12.523760. [PMID: 36711531 PMCID: PMC9882155 DOI: 10.1101/2023.01.12.523760] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Senescence drives organismal aging, yet the deep characterization of senescent cells in vivo remains incomplete. Here, we applied mass cytometry by time-of-flight (CyTOF) using carefully validated antibodies to analyze senescent cells at single-cell resolution. We used multiple criteria to identify senescent mesenchymal cells that were growth arrested and resistant to apoptosis (p16+/Ki67-/BCL-2+; "p16KB" cells). These cells were highly enriched for senescence-associated secretory phenotype (SASP) and DNA damage markers and were strongly associated with age. p16KB cell percentages were also increased in CD24+ osteolineage cells, which exhibited an inflammatory SASP in aged mice and were robustly cleared by both genetic and pharmacologic senolytic therapies. Following isolation, CD24+ skeletal cells exhibited growth arrest, SA-βgal positivity, and impaired osteogenesis in vitro . These studies thus provide a new approach using multiplexed protein profiling by CyTOF to define senescent mesenchymal cells in vivo and identify a highly inflammatory, senescent CD24+ osteolineage population cleared by senolytics.
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Affiliation(s)
- Madison L. Doolittle
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - Dominik Saul
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
- Department for Trauma and Reconstructive Surgery, BG Clinic, University of Tübingen, Germany
| | - Japneet Kaur
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - Jennifer L. Rowsey
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - Stephanie J. Vos
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - Kevin D. Pavelko
- Department of Immunology, Mayo Clinic, Rochester, MN, 55905, USA
| | - Joshua N. Farr
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - David G. Monroe
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
| | - Sundeep Khosla
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN 55905, USA
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Doolittle ML, Saul D, Kaur J, Rowsey JL, Eckhardt B, Vos S, Grain S, Kroupova K, Ruan M, Weivoda M, Oursler MJ, Farr JN, Monroe DG, Khosla S. Skeletal Effects of Inducible ERα Deletion in Osteocytes in Adult Mice. J Bone Miner Res 2022; 37:1750-1760. [PMID: 35789113 PMCID: PMC9474695 DOI: 10.1002/jbmr.4644] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [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: 03/04/2022] [Revised: 06/28/2022] [Accepted: 07/02/2022] [Indexed: 11/12/2022]
Abstract
Estrogen is known to regulate bone metabolism in both women and men, but substantial gaps remain in our knowledge of estrogen and estrogen receptor alpha (ERα) regulation of adult bone metabolism. Studies using global ERα-knockout mice were confounded by high circulating sex-steroid levels, and osteocyte/osteoblast-specific ERα deletion may be confounded by ERα effects on growth versus the adult skeleton. Thus, we developed mice expressing the tamoxifen-inducible CreERT2 in osteocytes using the 8-kilobase (kb) Dmp1 promoter (Dmp1CreERT2 ). These mice were crossed with ERαfl//fl mice to create ERαΔOcy mice, permitting inducible osteocyte-specific ERα deletion in adulthood. After intermittent tamoxifen treatment of adult 4-month-old mice for 1 month, female, but not male, ERαΔOcy mice exhibited reduced spine bone volume fraction (BV/TV (-20.1%, p = 0.004) accompanied by decreased trabecular bone formation rate (-18.9%, p = 0.0496) and serum P1NP levels (-38.9%, p = 0.014). Periosteal (+65.6%, p = 0.004) and endocortical (+64.1%, p = 0.003) expansion were higher in ERαΔOcy mice compared to control (Dmp1CreERT2 ) mice at the tibial diaphysis, reflecting the known effects of estrogen to inhibit periosteal apposition and promote endocortical formation. Increases in Sost (2.1-fold, p = 0.001) messenger RNA (mRNA) levels were observed in trabecular bone at the spine in ERαΔOcy mice, consistent with previous reports that estrogen deficiency is associated with increased circulating sclerostin as well as bone SOST mRNA levels in humans. Further, the biological consequences of increased Sost expression were reflected in significant overall downregulation in panels of osteoblast and Wnt target genes in osteocyte-enriched bones from ERαΔOcy mice. These findings thus establish that osteocytic ERα is critical for estrogen action in female, but not male, adult bone metabolism. Moreover, the reduction in bone formation accompanied by increased Sost, decreased osteoblast, and decreased Wnt target gene expression in ERαΔOcy mice provides a direct link in vivo between ERα and Wnt signaling. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Madison L. Doolittle
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Dominik Saul
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Japneet Kaur
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Jennifer L. Rowsey
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Brittany Eckhardt
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Stephanie Vos
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Sarah Grain
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Kveta Kroupova
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
- University Hospital Hradec Kralove and the Faculty of Medicine in Hradec Kralove, Czech Republic
| | - Ming Ruan
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Megan Weivoda
- Robert and Arlene Kogod Center on Aging and Division of Hematology, Mayo Clinic College of Medicine, Rochester, MN
| | - Merry Jo Oursler
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Joshua N. Farr
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - David G. Monroe
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
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Kaur J, Saul D, Doolittle ML, Rowsey JL, Vos SJ, Farr JN, Khosla S, Monroe DG. Identification of a suitable endogenous control miRNA in bone aging and senescence. Gene X 2022; 835:146642. [PMID: 35700807 PMCID: PMC9533812 DOI: 10.1016/j.gene.2022.146642] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 04/15/2022] [Accepted: 06/02/2022] [Indexed: 11/04/2022] Open
Abstract
MicroRNAs (miRNAs) are promising tools as biomarkers and therapeutic agents in various chronic diseases such as osteoporosis, cancers, type I and II diabetes, and cardiovascular diseases. Considering the rising interest in the regulatory role of miRNAs in bone metabolism, aging, and cellular senescence, accurate normalization of qPCR-based miRNA expression data using an optimal endogenous control becomes crucial. We used a systematic approach to select candidate endogenous control miRNAs that exhibit high stability with aging from our miRNA sequence data and literature search. Validation of miRNA expression was performed using qPCR and their comprehensive stability was assessed using the RefFinder tool which is based on four statistical algorithms: GeNorm, NormFinder, BestKeeper, and comparative delta CT. The selected endogenous control was then validated for its stability in mice and human bone tissues, and in bone marrow stromal cells (BMSCs) following induction of senescence and senolytic treatment. Finally, the utility of selected endogenous control versus U6 was tested by using each as a normalizer to measure the expression of miR-34a, a miRNA known to increase with age and senescence. Our results show that Let-7f did not change across the groups with aging, senescence or senolytic treatment, and was the most stable miRNA, whereas U6 was the least stable. Moreover, using Let-7f as a normalizer resulted in significantly increased expression of miR-34a with aging and senescence and decreased expression following senolytic treatment. However, the expression pattern for miR-34a reversed for each of these conditions when U6 was used as a normalizer. We show that optimal endogenous control miRNAs, such as Let-7f, are essential for accurate normalization of miRNA expression data to increase the reliability of results and prevent misinterpretation. Moreover, we present a systematic strategy that is transferrable and can easily be used to identify endogenous control miRNAs in other biological systems and conditions.
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Affiliation(s)
- Japneet Kaur
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - Dominik Saul
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - Madison L Doolittle
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - Jennifer L Rowsey
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - Stephanie J Vos
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - Joshua N Farr
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - Sundeep Khosla
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA
| | - David G Monroe
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA; Robert and Arlene Kogod Center on Aging, Rochester, MN 55905, USA.
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9
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Saul D, Monroe DG, Rowsey JL, Kosinsky RL, Vos SJ, Doolittle ML, Farr JN, Khosla S. Modulation of fracture healing by the transient accumulation of senescent cells. eLife 2021; 10:69958. [PMID: 34617510 PMCID: PMC8526061 DOI: 10.7554/elife.69958] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [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: 05/02/2021] [Accepted: 09/29/2021] [Indexed: 12/26/2022] Open
Abstract
Senescent cells have detrimental effects across tissues with aging but may have beneficial effects on tissue repair, specifically on skin wound healing. However, the potential role of senescent cells in fracture healing has not been defined. Here, we performed an in silico analysis of public mRNAseq data and found that senescence and senescence-associated secretory phenotype (SASP) markers increased during fracture healing. We next directly established that the expression of senescence biomarkers increased markedly during murine fracture healing. We also identified cells in the fracture callus that displayed hallmarks of senescence, including distension of satellite heterochromatin and telomeric DNA damage; the specific identity of these cells, however, requires further characterization. Then, using a genetic mouse model (Cdkn2aLUC) containing a Cdkn2aInk4a-driven luciferase reporter, we demonstrated transient in vivo senescent cell accumulation during callus formation. Finally, we intermittently treated young adult mice following fracture with drugs that selectively eliminate senescent cells (‘senolytics’, Dasatinib plus Quercetin), and showed that this regimen both decreased senescence and SASP markers in the fracture callus and significantly accelerated the time course of fracture healing. Our findings thus demonstrate that senescent cells accumulate transiently in the murine fracture callus and, in contrast to the skin, their clearance does not impair but rather improves fracture healing.
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Affiliation(s)
- Dominik Saul
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States.,Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany
| | - David G Monroe
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States.,Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, United States
| | - Jennifer L Rowsey
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Robyn Laura Kosinsky
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, United States
| | - Stephanie J Vos
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Madison L Doolittle
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States
| | - Joshua N Farr
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States.,Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, United States
| | - Sundeep Khosla
- Division of Endocrinology, Mayo Clinic, Rochester, United States.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, United States.,Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August-University of Goettingen, Goettingen, Germany.,Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, United States
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10
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Aquino-Martinez R, Eckhardt BA, Rowsey JL, Fraser DG, Khosla S, Farr JN, Monroe DG. Senescent cells exacerbate chronic inflammation and contribute to periodontal disease progression in old mice. J Periodontol 2020; 92:1483-1495. [PMID: 33341947 DOI: 10.1002/jper.20-0529] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 07/13/2020] [Revised: 12/02/2020] [Accepted: 12/13/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Coinciding with other chronic comorbidities, the prevalence of periodontal disease increases with aging. Mounting evidence has established that senescent cells accumulate at sites of age-related pathologies, where they promote "non-microbial" inflammation. We hypothesized that alveolar bone osteocytes develop senescence characteristics in old age. METHODS Alveolar bone samples were obtained from young (6 months) and old (20 to 22 months) mice to evaluate the expression of senescence biomarkers by immunofluorescent staining. Osteocyte-enriched fractions were used to characterize the age-related senescence-associated secretory phenotype (SASP) gene expression profile. Primary alveolar bone cells were exposed to the SASP via in vitro senescent conditioned media (SCM) administration. A multiplex assay confirmed protein levels of specific cytokines. Interactions with bacterial components were evaluated by stimulating cells with lipopolysaccharide (LPS). RESULTS Increased senescence-associated distension of satellites (SADS) and p16Ink4a mRNA expression were identified in alveolar bone osteocytes with aging. These findings were associated with increased levels of DNA damage, and activated p38 MAPK, both inducers of senescence. Furthermore, interleukin-6 (IL6), IL17, IGFBP4, and MMP13 were significantly upregulated with aging in osteocyte-enriched samples. Interestingly, SCM potentiated the LPS-induced expression of IL1α, IL1β, and IL6. Cell migration and differentiation were also impeded by SCM. These in vitro effects were ameliorated by the p38 MAPK inhibitor SB202190. CONCLUSIONS Accumulation of senescent osteocytes contributes to deterioration of the periodontal environment by exacerbating chronic inflammation and reducing regeneration in old age. Cellular senescence is a cell-intrinsic response to DNA damage, and a host-related mechanism associated with aging that could potentiate inflammation induced by bacterial components.
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Affiliation(s)
- Ruben Aquino-Martinez
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Brittany A Eckhardt
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Jennifer L Rowsey
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Daniel G Fraser
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN
| | - Sundeep Khosla
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN
| | - Joshua N Farr
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN
| | - David G Monroe
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN.,Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN
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11
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Eckhardt BA, Rowsey JL, Thicke BS, Fraser DG, O’Grady KL, Bondar OP, Hines JM, Singh RJ, Thoreson AR, Rakshit K, Lagnado AB, Passos JF, Vella A, Matveyenko AV, Khosla S, Monroe DG, Farr JN. Accelerated osteocyte senescence and skeletal fragility in mice with type 2 diabetes. JCI Insight 2020; 5:135236. [PMID: 32267250 PMCID: PMC7253018 DOI: 10.1172/jci.insight.135236] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [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: 11/25/2019] [Accepted: 03/26/2020] [Indexed: 12/16/2022] Open
Abstract
The worldwide prevalence of type 2 diabetes (T2D) is increasing. Despite normal to higher bone density, patients with T2D paradoxically have elevated fracture risk resulting, in part, from poor bone quality. Advanced glycation endproducts (AGEs) and inflammation as a consequence of enhanced receptor for AGE (RAGE) signaling are hypothesized culprits, although the exact mechanisms underlying skeletal dysfunction in T2D are unclear. Lack of inducible models that permit environmental (in obesity) and temporal (after skeletal maturity) control of T2D onset has hampered progress. Here, we show in C57BL/6 mice that a onetime pharmacological intervention (streptozotocin, STZ) initiated in adulthood combined with high-fat diet-induced (HFD-induced) obesity caused hallmark features of human adult-onset T2D, including prolonged hyperglycemia, insulin resistance, and pancreatic β cell dysfunction, but not complete destruction. In addition, HFD/STZ (i.e., T2D) resulted in several changes in bone quality that closely mirror those observed in humans, including compromised bone microarchitecture, reduced biomechanical strength, impaired bone material properties, altered bone turnover, and elevated levels of the AGE CML in bone and blood. Furthermore, T2D led to the premature accumulation of senescent osteocytes with a unique proinflammatory signature. These findings highlight the RAGE pathway and senescent cells as potential targets to treat diabetic skeletal fragility.
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Affiliation(s)
| | | | | | - Daniel G. Fraser
- Division of Endocrinology
- Robert and Arlene Kogod Center on Aging
| | | | | | | | | | - Andrew R. Thoreson
- Materials and Structural Testing Core
- Department of Physical Medicine and Rehabilitation, and
| | - Kuntol Rakshit
- Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Anthony B. Lagnado
- Robert and Arlene Kogod Center on Aging
- Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - João F. Passos
- Robert and Arlene Kogod Center on Aging
- Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Aleksey V. Matveyenko
- Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Sundeep Khosla
- Division of Endocrinology
- Robert and Arlene Kogod Center on Aging
| | - David G. Monroe
- Division of Endocrinology
- Robert and Arlene Kogod Center on Aging
| | - Joshua N. Farr
- Division of Endocrinology
- Robert and Arlene Kogod Center on Aging
- Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
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12
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Aquino-Martinez R, Rowsey JL, Fraser DG, Eckhardt BA, Khosla S, Farr JN, Monroe DG. LPS-induced premature osteocyte senescence: Implications in inflammatory alveolar bone loss and periodontal disease pathogenesis. Bone 2020; 132:115220. [PMID: 31904537 PMCID: PMC6990876 DOI: 10.1016/j.bone.2019.115220] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 12/13/2019] [Accepted: 12/31/2019] [Indexed: 12/21/2022]
Abstract
Cellular senescence is associated with inflammation and extracellular matrix tissue remodeling through the secretion of proteins termed the senescence-associated secretory phenotype (SASP). Although osteocyte senescence in older individuals in the skeleton is well recognized, whether young alveolar osteocytes can also become senescent is unknown. This is potentially important in the context of periodontal disease, which is an inflammatory condition caused by a gradual change from symbiotic to pathogenic oral microflora that can lead to tooth loss. Our aim was to identify whether senescent osteocytes accumulate in young alveolar bone and whether bacterial-derived lipopolysaccharide (LPS) can influence cellular senescence in alveolar bone. An osteocyte-enriched cell population isolated from alveolar bone expressed increased levels of the known senescence marker p16Ink4a, as well as select SASP markers known to be implicated alveolar bone resorption (Icam1, Il6, Il17, Mmp13 and Tnfα), compared to ramus control cells. Increased senescence of alveolar bone osteocytes was also observed in vivo using the senescence-associated distension of satellites (SADS) assay and increased γH2AX, a marker of DNA damage associated with senescent cells. To approximate a bacterial infection in vitro, alveolar osteocytes were treated with LPS. We found increased expression of various senescence and SASP markers, increased γH2AX staining, increased SA-β-Gal activity and the redistribution of F-actin leading to a larger and flattened cell morphology, all hallmarks of cellular senescence. In conclusion, our data suggests a model whereby bacterial-derived LPS stimulates premature alveolar osteocyte senescence, which in combination with the resultant SASP, could potentially contribute to the onset of alveolar bone loss.
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Affiliation(s)
- Ruben Aquino-Martinez
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Jennifer L Rowsey
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Daniel G Fraser
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Brittany A Eckhardt
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Sundeep Khosla
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA; Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA
| | - Joshua N Farr
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA; Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA.
| | - David G Monroe
- Department of Medicine, Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA; Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, USA.
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13
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Farr JN, Rowsey JL, Eckhardt BA, Thicke BS, Fraser DG, Tchkonia T, Kirkland JL, Monroe DG, Khosla S. Independent Roles of Estrogen Deficiency and Cellular Senescence in the Pathogenesis of Osteoporosis: Evidence in Young Adult Mice and Older Humans. J Bone Miner Res 2019; 34:1407-1418. [PMID: 30913313 PMCID: PMC6697189 DOI: 10.1002/jbmr.3729] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/27/2019] [Accepted: 03/15/2019] [Indexed: 11/10/2022]
Abstract
Estrogen deficiency is a seminal mechanism in the pathogenesis of osteoporosis. Mounting evidence, however, establishes that cellular senescence, a fundamental mechanism that drives multiple age-related diseases, also causes osteoporosis. Recently, we systematically identified an accumulation of senescent cells, characterized by increased p16Ink4a and p21Cip1 levels and development of a senescence-associated secretory phenotype (SASP), in mouse bone/marrow and human bone with aging. We then demonstrated that elimination of senescent cells prevented age-related bone loss using multiple approaches, eg, treating old mice expressing a "suicide" transgene, INK-ATTAC, with AP20187 to induce apoptosis of p16Ink4a -senescent cells or periodically treating old wild-type mice with "senolytics," ie, drugs that eliminate senescent cells. Here, we investigate a possible role for estrogen in the regulation of cellular senescence using multiple approaches. First, sex steroid deficiency 2 months after ovariectomy (OVX, n = 15) or orchidectomy (ORCH, n = 15) versus sham surgery (SHAM, n = 15/sex) in young adult (4-month-old) wild-type mice did not alter senescence biomarkers or induce a SASP in bone. Next, in elderly postmenopausal women, 3 weeks of estrogen therapy (n = 10; 74 ± 5 years) compared with no treatment (n = 10; 78 ± 5 years) did not alter senescence biomarkers or the SASP in human bone biopsies. Finally, young adult (4-month-old) female INK-ATTAC mice were randomized (n = 17/group) to SHAM+Vehicle, OVX+Vehicle, or OVX+AP20187 for 2 months. As anticipated, OVX+Vehicle caused significant trabecular/cortical bone loss compared with SHAM+Vehicle. However, treatment with AP20187, which eliminates senescent cells in INK-ATTAC mice, did not rescue the OVX-induced bone loss or alter senescence biomarkers. Collectively, our data establish independent roles of estrogen deficiency and cellular senescence in the pathogenesis of osteoporosis, which has important implications for testing novel senolytics for skeletal efficacy, as these drugs will need to be evaluated in preclinical models of aging as opposed to the current FDA model of prevention of OVX-induced bone loss. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Joshua N Farr
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Jennifer L Rowsey
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Brittany A Eckhardt
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Brianne S Thicke
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Daniel G Fraser
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Tamar Tchkonia
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - James L Kirkland
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - David G Monroe
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, MN, USA
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