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Liang J, Zhang N, Li G, Zhou X, Li Z, Zhan Z, Fan J, Zheng C, Zhu Q, Qi J, Yan L. Piezo1 promotes peripheral nerve fibrotic scar formation through Schwann cell senescence. Neurosci Lett 2024; 837:137916. [PMID: 39059459 DOI: 10.1016/j.neulet.2024.137916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Revised: 07/12/2024] [Accepted: 07/23/2024] [Indexed: 07/28/2024]
Abstract
After peripheral nerve injury (PNI), the long-term healing process at the injury site involves a progressive accumulation of collagen fibers and the development of localized scar tissue. Excessive formation of scar tissue within nerves hinders the process of nerve repair. In this study, we demonstrate that scar formation following nerve injury induces alterations in the local physical microenvironment, specifically an increase in nerve stiffness. Recent research has indicated heightened expression of Piezo1 in Schwann cells (SCs). Our findings also indicate Piezo1 expression in SCs and its association with suppressed proliferation and migration. Transcriptomic data suggests that activation of Piezo1 results in elevated expression of senescence-associated genes. GO enrichment analysis reveals upregulation of the TGF-β pathway. Overall, our study highlights the potential for Piezo1-induced signaling to regulate SC senescence and its potential significance in the pathophysiology of fibrotic scar formation surrounding peripheral nerves.
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Affiliation(s)
- Jing Liang
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Nan Zhang
- Department of Medical Ultrasonics, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ge Li
- Guangdong Provincial Key Laboratory of Pathogenesis, Targeted Prevention and Treatment of Heart Disease, Medical Research Institute, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Xiang Zhou
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory for Orthopedics and Traumatology, Guangzhou, China
| | - Zhe Li
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Zhaoying Zhan
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jingyuan Fan
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Canbin Zheng
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory for Orthopedics and Traumatology, Guangzhou, China
| | - Qingtang Zhu
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory for Orthopedics and Traumatology, Guangzhou, China
| | - Jian Qi
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory for Orthopedics and Traumatology, Guangzhou, China.
| | - Liwei Yan
- Department of Microsurgery, Trauma and Hand Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China; Guangdong Provincial Key Laboratory for Orthopedics and Traumatology, Guangzhou, China.
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Froemming MN, Khosla S, Farr JN. Marrow Adipocyte Senescence in the Pathogenesis of Bone Loss. Curr Osteoporos Rep 2024; 22:378-386. [PMID: 38829487 DOI: 10.1007/s11914-024-00875-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/23/2024] [Indexed: 06/05/2024]
Abstract
PURPOSE OF REVIEW Beyond aging, senescent cells accumulate during multiple pathological conditions, including chemotherapy, radiation, glucocorticoids, obesity, and diabetes, even earlier in life. Therefore, cellular senescence represents a unifying pathogenic mechanism driving skeletal and metabolic disorders. However, whether senescent bone marrow adipocytes (BMAds) are causal in mediating skeletal dysfunction has only recently been evaluated. RECENT FINDINGS Despite evidence of BMAd senescence following glucocorticoid therapy, additional evidence for BMAd senescence in other conditions has thus far been limited. Because the study of BMAds presents unique challenges making these cells difficult to isolate and image, here we review issues and approaches to overcome such challenges, and present advancements in isolation and histological techniques that may help with the future study of senescent BMAds. Further insights into the roles of BMAd senescence in the pathogenesis of skeletal dysfunction may have important basic science and clinical implications for human physiology and disease.
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Affiliation(s)
- Mitchell N Froemming
- Division of Endocrinology, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center On Aging, Rochester, MN, 55905, USA
| | - Sundeep Khosla
- Division of Endocrinology, Rochester, MN, 55905, USA
- Robert and Arlene Kogod Center On Aging, Rochester, MN, 55905, USA
| | - Joshua N Farr
- Division of Endocrinology, Rochester, MN, 55905, USA.
- Robert and Arlene Kogod Center On Aging, Rochester, MN, 55905, USA.
- Division of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, 55905, USA.
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Lawrence M, Goyal A, Pathak S, Ganguly P. Cellular Senescence and Inflammaging in the Bone: Pathways, Genetics, Anti-Aging Strategies and Interventions. Int J Mol Sci 2024; 25:7411. [PMID: 39000517 PMCID: PMC11242738 DOI: 10.3390/ijms25137411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/22/2024] [Accepted: 07/03/2024] [Indexed: 07/16/2024] Open
Abstract
Advancing age is associated with several age-related diseases (ARDs), with musculoskeletal conditions impacting millions of elderly people worldwide. With orthopedic conditions contributing towards considerable number of patients, a deeper understanding of bone aging is the need of the hour. One of the underlying factors of bone aging is cellular senescence and its associated senescence associated secretory phenotype (SASP). SASP comprises of pro-inflammatory markers, cytokines and chemokines that arrest cell growth and development. The accumulation of SASP over several years leads to chronic low-grade inflammation with advancing age, also known as inflammaging. The pathways and molecular mechanisms focused on bone senescence and inflammaging are currently limited but are increasingly being explored. Most of the genes, pathways and mechanisms involved in senescence and inflammaging coincide with those associated with cancer and other ARDs like osteoarthritis (OA). Thus, exploring these pathways using techniques like sequencing, identifying these factors and combatting them with the most suitable approach are crucial for healthy aging and the early detection of ARDs. Several approaches can be used to aid regeneration and reduce senescence in the bone. These may be pharmacological, non-pharmacological and lifestyle interventions. With increasing evidence towards the intricate relationship between aging, senescence, inflammation and ARDs, these approaches may also be used as anti-aging strategies for the aging bone marrow (BM).
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Affiliation(s)
- Merin Lawrence
- School of Biological and Chemical Sciences, University of Galway, H91W2TY Galway, Ireland
| | - Abhishek Goyal
- RAS Life Science Solutions, Stresemannallee 61, 60596 Frankfurt, Germany
| | - Shelly Pathak
- Observational and Pragmatic Research Institute, 5 Coles Lane, Oakington, Cambridge CB24 3BA, UK
| | - Payal Ganguly
- Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Leeds LS9 7JT, UK
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Lecka-Czernik B, Khan MP, Letson J, Baroi S, Chougule A. Regulatory Effect of Osteocytes on Extramedullary and Bone Marrow Adipose Tissue Development and Function. Curr Osteoporos Rep 2024; 22:301-307. [PMID: 38625510 PMCID: PMC11186862 DOI: 10.1007/s11914-024-00871-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/05/2024] [Indexed: 04/17/2024]
Abstract
PURPOSE OF REVIEW This review summarizes evidence on osteocyte support of extramedullary and bone marrow adipocyte development and discusses the role of endogenous osteocyte activities of nuclear receptors peroxisome proliferator-activated receptor gamma (PPARG) and alpha (PPARA) in this support. RECENT FINDINGS PPARG and PPARA proteins, key regulators of glucose and fatty acid metabolism, are highly expressed in osteocytes. They play significant roles in the regulation of osteocyte secretome and osteocyte bioenergetics; both activities contributing to the levels of systemic energy metabolism in part through an effect on metabolic function of extramedullary and bone marrow adipocytes. The PPARs-controlled osteocyte endocrine/paracrine activities, including sclerostin expression, directly regulate adipocyte function, while the PPARs-controlled osteocyte fuel utilization and oxidative phosphorylation contribute to the skeletal demands for glucose and fatty acids, whose availability is under the control of adipocytes. Bone is an inherent element of systemic energy metabolism with PPAR nuclear receptors regulating osteocyte-adipocyte metabolic axes.
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Affiliation(s)
- Beata Lecka-Czernik
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA.
| | - Mohd Parvez Khan
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
| | - Joshua Letson
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
| | - Sudipta Baroi
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
- Harvard University, School of Dental Medicine, Boston, MA, 02115, USA
| | - Amit Chougule
- Department of Orthopaedic Surgery, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, 43614, USA
- University of Michigan, Ann Arbor, MI, 48109, USA
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Liu B, Zhang J, Zhang J, Ji X, Wang R, Gong A, Miao D. Metformin prevents mandibular bone loss in a mouse model of accelerated aging by correcting dysregulated AMPK-mTOR signaling and osteoclast differentiation. J Orthop Translat 2024; 46:129-142. [PMID: 38867742 PMCID: PMC11167204 DOI: 10.1016/j.jot.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 03/02/2024] [Accepted: 03/08/2024] [Indexed: 06/14/2024] Open
Abstract
Background Age-related mandibular osteoporosis frequently causes loose teeth, difficulty eating, and disfiguration in elders. Bmi1-/- mice displaying accelerated skeletal aging represent a useful model for testing interventions against premature jaw bone loss. As an anti-aging agent, metformin may ameliorate molecular dysfunction driving osteoporosis pathogenesis. We explored the mechanisms of mandibular osteopenia in Bmi1-/- mice and prevention by metformin treatment. Methods Three mouse groups were utilized: wild-type controls, untreated Bmi1-/-, and Bmi1-/- receiving 1 g/kg metformin diet. Mandibular bone phenotype was assessed by X-ray, micro-CT, histology, and immunohistochemistry. AMPK-mTOR pathway analysis, senescence markers, osteoblast and osteoclast gene expression were evaluated in jaw tissue. Osteoclast differentiation capacity and associated signaling molecules were examined in cultured Bmi1-/- bone marrow mononuclear cells ± metformin. Results Bmi1 loss reduced mandible bone density concomitant with decreased AMPK activity, increased mTOR signaling and cellular senescence in jaw tissue versus wild-type controls. This was accompanied by impaired osteoblast function and upregulated osteoclastogenesis markers. Metformin administration normalized AMPK-mTOR balance, oxidative stress and senescence signaling to significantly improve mandibular bone architecture in Bmi1-/- mice. In culture, metformin attenuated excessive osteoclast differentiation from Bmi1-/- marrow precursors by correcting dysregulated AMPK-mTOR-p53 pathway activity and suppressing novel pro-osteoclastogenic factor Stfa1. Conclusions Our study newly demonstrates metformin prevents accelerated jaw bone loss in a premature aging murine model by rectifying molecular dysfunction in cellular energy sensors, redox state, senescence and osteoclastogenesis pathways. Targeting such age-associated mechanisms contributing to osteoporosis pathogenesis may help maintain oral health and aesthetics in the growing elderly population. Translational potential The pronounced mandibular osteopenia exhibited in Bmi1-/- mice represents an accelerated model of jaw bone deterioration observed during human aging. Our finding that metformin preserves mandibular bone integrity in this progeroid model has important clinical implications. As an inexpensive oral medication already widely used to manage diabetes, metformin holds translational promise for mitigating age-related osteoporosis. The mandible is essential for chewing, swallowing, speech and facial structure, but progressively loses bone mass and strength with advancing age, significantly impacting seniors' nutrition, physical function and self-image. Our results suggest metformin's ability to rectify cellular energy imbalance, oxidative stress and osteoclast overactivity may help maintain jaw bone health into old age. Further research is still needed given metformin's multifaceted biology and bone regulation by diverse pathways. However, this preclinical study provides a strong rationale for clinical trials specifically examining mandibular outcomes in elderly subjects receiving standard metformin treatment for diabetes or prediabetes. Determining if metformin supplementation can prevent or delay oral disability and disfigurement from senescent jaw bone loss in the growing aged population represents an important public health priority. In summary, our mechanistic findings in a genetic mouse model indicate metformin merits investigation in rigorous human studies for alleviating morbidity associated with age-related mandibular osteoporosis.
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Affiliation(s)
- Boyang Liu
- Department of Human Anatomy, Histology and Embryology, The Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, PR China
| | - Jiao Zhang
- Department of Plastic Surgery, Affiliated Friendship Plastic Surgery Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, PR China
| | - Jinge Zhang
- Department of Human Anatomy, Histology and Embryology, The Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, PR China
| | - Xiaolei Ji
- Department of Stomatology, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing, PR China
| | - Rong Wang
- Department of Human Anatomy, Histology and Embryology, The Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, PR China
| | - Aixiu Gong
- Department of Stomatology, Children's Hospital of Nanjing Medical University, Nanjing, PR China
| | - Dengshun Miao
- Department of Human Anatomy, Histology and Embryology, The Research Center for Bone and Stem Cells, Nanjing Medical University, Nanjing, PR China
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Ansari MM, Ghosh M, Lee DS, Son YO. Senolytic therapeutics: An emerging treatment modality for osteoarthritis. Ageing Res Rev 2024; 96:102275. [PMID: 38494091 DOI: 10.1016/j.arr.2024.102275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/15/2024] [Accepted: 03/14/2024] [Indexed: 03/19/2024]
Abstract
Osteoarthritis (OA), a chronic joint disease affecting millions of people aged over 65 years, is the main musculoskeletal cause of diminished joint mobility in the elderly. It is characterized by lingering pain and increasing deterioration of articular cartilage. Aging and accumulation of senescent cells (SCs) in the joints are frequently associated with OA. Apoptosis resistance; irreversible cell cycle arrest; increased p16INK4a expression, secretion of senescence-associated secretory phenotype factors, senescence-associated β-galactosidase levels, secretion of extracellular vesicles, and levels of reactive oxygen and reactive nitrogen species; and mitochondrial dysregulation are some common changes in cellular senescence in joint tissues. Development of OA correlates with an increase in the density of SCs in joint tissues. Senescence-associated secretory phenotype has been linked to OA and cartilage breakdown. Senolytics and therapeutic pharmaceuticals are being focused upon for OA management. SCs can be selectively eliminated or killed by senolytics to halt the pathogenesis and progression of OA. Comprehensive understanding of how aging affects joint dysfunction will benefit OA patients. Here, we discuss age-related mechanisms associated with OA pathogenesis and senolytics as an emerging modality in the management of age-related SCs and pathogenesis of OA in preclinical and clinical studies.
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Affiliation(s)
- Md Meraj Ansari
- Department of Animal Biotechnology, Faculty of Biotechnology, College of Applied Life Sciences, Jeju National University, Jeju-si 63243, Republic of Korea
| | - Mrinmoy Ghosh
- Department of Animal Biotechnology, Faculty of Biotechnology, College of Applied Life Sciences, Jeju National University, Jeju-si 63243, Republic of Korea; Department of Biotechnology, School of Bio, Chemical and Processing Engineering (SBCE), Kalasalingam Academy of Research and Education, Krishnankoil 626126, India
| | - Dong-Sun Lee
- Interdisciplinary Graduate Program in Advanced Convergence Technology and Science, Jeju National University, Jeju-si 63243, Republic of Korea; Bio-Health Materials Core-Facility Center, Jeju National University, Jeju 63243, Republic of Korea; Faculty of Biotechnology, College of Applied Life Sciences, Jeju National University, Jeju-si 63243, Republic of Korea; Practical Translational Research Center, Jeju National University, Jeju 63243, Republic of Korea.
| | - Young-Ok Son
- Department of Animal Biotechnology, Faculty of Biotechnology, College of Applied Life Sciences, Jeju National University, Jeju-si 63243, Republic of Korea; Interdisciplinary Graduate Program in Advanced Convergence Technology and Science, Jeju National University, Jeju-si 63243, Republic of Korea; Bio-Health Materials Core-Facility Center, Jeju National University, Jeju 63243, Republic of Korea; Practical Translational Research Center, Jeju National University, Jeju 63243, Republic of Korea.
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Schurman CA, Kaya S, Dole N, Luna NMM, Castillo N, Potter R, Rose JP, Bons J, King CD, Burton JB, Schilling B, Melov S, Tang S, Schaible E, Alliston T. Aging impairs the osteocytic regulation of collagen integrity and bone quality. Bone Res 2024; 12:13. [PMID: 38409111 PMCID: PMC10897167 DOI: 10.1038/s41413-023-00303-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/31/2023] [Accepted: 11/13/2023] [Indexed: 02/28/2024] Open
Abstract
Poor bone quality is a major factor in skeletal fragility in elderly individuals. The molecular mechanisms that establish and maintain bone quality, independent of bone mass, are unknown but are thought to be primarily determined by osteocytes. We hypothesize that the age-related decline in bone quality results from the suppression of osteocyte perilacunar/canalicular remodeling (PLR), which maintains bone material properties. We examined bones from young and aged mice with osteocyte-intrinsic repression of TGFβ signaling (TβRIIocy-/-) that suppresses PLR. The control aged bone displayed decreased TGFβ signaling and PLR, but aging did not worsen the existing PLR suppression in male TβRIIocy-/- bone. This relationship impacted the behavior of collagen material at the nanoscale and tissue scale in macromechanical tests. The effects of age on bone mass, density, and mineral material behavior were independent of osteocytic TGFβ. We determined that the decline in bone quality with age arises from the loss of osteocyte function and the loss of TGFβ-dependent maintenance of collagen integrity.
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Affiliation(s)
- Charles A Schurman
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, 94143, USA
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, 94143, USA
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
| | - Serra Kaya
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, 94143, USA
| | - Neha Dole
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, 94143, USA
| | - Nadja M Maldonado Luna
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, 94143, USA
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, 94143, USA
| | - Natalia Castillo
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, 94143, USA
| | - Ryan Potter
- Washington University in St Louis, Department of Orthopedics, St. Louis, MO, 63130, USA
| | - Jacob P Rose
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
| | - Joanna Bons
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
| | | | - Jordan B Burton
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
| | | | - Simon Melov
- Buck Institute for Research on Aging, Novato, CA, 94945, USA
| | - Simon Tang
- Washington University in St Louis, Department of Orthopedics, St. Louis, MO, 63130, USA
| | - Eric Schaible
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, 94143, USA.
- UC Berkeley/UCSF Graduate Program in Bioengineering, San Francisco, CA, 94143, USA.
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Meas SJ, Daire GM, Friedman MA, DeNapoli R, Ghosh P, Farr JN, Donahue HJ. A comparison of bone microarchitectural and transcriptomic changes in murine long bones in response to hindlimb unloading and aging. Bone 2024; 179:116973. [PMID: 37996046 DOI: 10.1016/j.bone.2023.116973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023]
Abstract
Age- and disuse-related bone loss both result in decreases in bone mineral density, cortical thickness, and trabecular thickness and connectivity. Disuse induces changes in the balance of bone formation and bone resorption like those seen with aging. There is a need to experimentally compare these two mechanisms at a structural and transcriptomic level to better understand how they may be similar or different. Bone microarchitecture and biomechanical properties were compared between 6- and 22-month-old C57BL/6 J male control mice and 6-month-old mice that were hindlimb unloaded (HLU) for 3 weeks. Epiphyseal trabecular bone was the compartment most affected by HLU and demonstrated an intermediate bone phenotype between age-matched controls and aged controls. RNA extracted from whole-bone marrow-flushed tibiae was sequenced and analyzed. Differential gene expression analysis additionally included 4-month-old male mice unloaded for 3 weeks compared to age-matched controls. Gene ontology analysis demonstrated that there were age-dependent differences in differentially expressed genes in young adult mice. Genes related to downregulation of cellular processes were most affected in 4-month-old mice after disuse whereas those related to mitochondrial function were most affected in 6-month-old mice. Cell-cycle transition was downregulated with aging. A publicly available dataset (GSE169292) from 3-month female C57BL/6 N mice unloaded for 7 days was included in ingenuity pathway analysis (IPA) with the other datasets. IPA was used to identify the leading canonical pathways and upstream regulators in each HLU age group. IPA identified "Senescence Pathway" as the second leading canonical pathway enriched in mice exposed to HLU. HLU induced activation of the senescence pathway in 3-month and 4-month-old mice but inhibited it in 6-month-old mice. In conclusion, we demonstrate that hindlimb unloading and aging initiate similar changes in bone microarchitecture and gene expression. However, aging is responsible for more significant transcriptome and tissue-level changes compared to hindlimb unloading.
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Affiliation(s)
- Steven J Meas
- Virginia Commonwealth University, Richmond, VA 23284, USA.
| | | | | | | | - Preetam Ghosh
- Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - Joshua N Farr
- Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Yao C, Sun J, Luo W, Chen H, Chen T, Chen C, Zhang B, Zhang Y. Down-expression of miR-494-3p in senescent osteocyte-derived exosomes inhibits osteogenesis and accelerates age-related bone loss via PTEN/PI3K/AKT pathway. Bone Joint Res 2024; 13:52-65. [PMID: 38295830 PMCID: PMC10830172 DOI: 10.1302/2046-3758.132.bjr-2023-0146.r2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2024] Open
Abstract
Aims To investigate the effects of senescent osteocytes on bone homeostasis in the progress of age-related osteoporosis and explore the underlying mechanism. Methods In a series of in vitro experiments, we used tert-Butyl hydroperoxide (TBHP) to induce senescence of MLO-Y4 cells successfully, and collected conditioned medium (CM) and senescent MLO-Y4 cell-derived exosomes, which were then applied to MC3T3-E1 cells, separately, to evaluate their effects on osteogenic differentiation. Furthermore, we identified differentially expressed microRNAs (miRNAs) between exosomes from senescent and normal MLO-Y4 cells by high-throughput RNA sequencing. Based on the key miRNAs that were discovered, the underlying mechanism by which senescent osteocytes regulate osteogenic differentiation was explored. Lastly, in the in vivo experiments, the effects of senescent MLO-Y4 cell-derived exosomes on age-related bone loss were evaluated in male SAMP6 mice, which excluded the effects of oestrogen, and the underlying mechanism was confirmed. Results The CM and exosomes collected from senescent MLO-Y4 cells inhibited osteogenic differentiation of MC3T3-E1 cells. RNA sequencing detected significantly lower expression of miR-494-3p in senescent MLO-Y4 cell-derived exosomes compared with normal exosomes. The upregulation of exosomal miR-494-3p by miRNA mimics attenuated the effects of senescent MLO-Y4 cell-derived exosomes on osteogenic differentiation. Luciferase reporter assay demonstrated that miR-494-3p targeted phosphatase and tensin homolog (PTEN), which is a negative regulator of the phosphoinositide 3-kinase (PI3K)/AKT pathway. Overexpression of PTEN or inhibition of the PI3K/AKT pathway blocked the functions of exosomal miR-494-3p. In SAMP6 mice, senescent MLO-Y4 cell-derived exosomes accelerated bone loss, which was rescued by upregulation of exosomal miR-494-3p. Conclusion Reduced expression of miR-494-3p in senescent osteocyte-derived exosomes inhibits osteogenic differentiation and accelerates age-related bone loss via PTEN/PI3K/AKT pathway.
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Affiliation(s)
- Chen Yao
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Jie Sun
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Wanxin Luo
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Hao Chen
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Tianhao Chen
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Cao Chen
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Bo Zhang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
| | - Yafeng Zhang
- Department of Orthopaedics, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China
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Zhang L, Guan Q, Wang Z, Feng J, Zou J, Gao B. Consequences of Aging on Bone. Aging Dis 2023:AD.2023.1115. [PMID: 38029404 DOI: 10.14336/ad.2023.1115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 11/16/2023] [Indexed: 12/01/2023] Open
Abstract
With the aging of the global population, the incidence of musculoskeletal diseases has been increasing, seriously affecting people's health. As people age, the microenvironment within skeleton favors bone resorption and inhibits bone formation, accompanied by bone marrow fat accumulation and multiple cellular senescence. Specifically, skeletal stem/stromal cells (SSCs) during aging tend to undergo adipogenesis rather than osteogenesis. Meanwhile, osteoblasts, as well as osteocytes, showed increased apoptosis, decreased quantity, and multiple functional limitations including impaired mechanical sensing, intercellular modulation, and exosome secretion. Also, the bone resorption function of macrophage-lineage cells (including osteoclasts and preosteoclasts) was significantly enhanced, as well as impaired vascularization and innervation. In this study, we systematically reviewed the effect of aging on bone and the within microenvironment (including skeletal cells as well as their intracellular structure variations, vascular structures, innervation, marrow fat distribution, and lymphatic system) caused by aging, and mechanisms of osteoimmune regulation of the bone environment in the aging state, and the causal relationship with multiple musculoskeletal diseases in addition with their potential therapeutic strategy.
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Affiliation(s)
- Lingli Zhang
- College of Athletic Performance, Shanghai University of Sport, Shanghai, China
| | - Qiao Guan
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Zhikun Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Jie Feng
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Jun Zou
- School of Exercise and Health, Shanghai University of Sport, Shanghai, China
| | - Bo Gao
- Department of Orthopedic Surgery, Xijing Hospital, Air Force Medical University, Xi'an, China
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Meas SJ, Daire GM, Friedman MA, DeNapoli R, Ghosh P, Farr JN, Donahue HJ. Hindlimb Unloading Induces Bone Microarchitectural and Transcriptomic Changes in Murine Long Bones in an Age-Dependent Manner. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.09.561510. [PMID: 37873408 PMCID: PMC10592678 DOI: 10.1101/2023.10.09.561510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Age and disuse-related bone loss both result in decreases in bone mineral density, cortical thickness, and trabecular thickness and connectivity. Disuse induces physiological changes in bone like those seen with aging. Bone microarchitecture and biomechanical properties were compared between 6- and 22-month-old C57BL/6J male control mice and 6-month-old mice that were hindlimb unloaded (HLU) for 3 weeks. Epiphyseal trabecular bone was the compartment most affected by HLU and demonstrated an intermediate bone phenotype between age-matched controls and aged controls. RNA extracted from whole-bone marrow-flushed tibiae was sequenced and analyzed. Differential gene expression analysis additionally included 4-month-old male mice unloaded for 3 weeks compared to age-matched controls. Gene ontology analysis demonstrated that there were age-dependent differences in differentially expressed genes. Genes related to downregulation of cellular processes were most affected in 4-month-old mice after disuse whereas those related to mitochondrial function were most affected in 6- month-old mice. Cell-cycle transition was downregulated with aging. A publicly available dataset (GSE169292) from 3-month female C57BL/6N mice unloaded for 7 days was included in ingenuity pathway analysis with the other datasets. IPA was used to identify the leading canonical pathways and upstream regulators in each HLU age group. IPA identified "Senescence Pathway" as the second leading canonical pathway enriched in mice exposed to HLU. HLU induced activation of the senescence pathway in 3- month and 4-month-old mice but inhibited it in 6-month-old mice. In conclusion, we demonstrate that hindlimb unloading and aging initiate similar changes in bone microarchitecture and gene expression. However, aging is responsible for more significant transcriptome and tissue-level changes compared to hindlimb unloading. Highlights Epiphyseal trabecular bone is most susceptible to hindlimb unloading.Hindlimb unloaded limbs resemble an intermediate phenotype between age-matched and aged controls.Hindlimb unloading induces gene expression changes that are age dependent and may lead to inflammation and/or mitochondrial dysfunction depending on context.Younger mice (3-4 months) activate the senescence pathway upon hindlimb unloading, whereas skeletally mature (6 months) mice inhibit it.
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12
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Pimenta-Lopes C, Sánchez-de-Diego C, Deber A, Egea-Cortés A, Valer JA, Alcalá A, Méndez-Lucas A, Esteve-Codina A, Rosa JL, Ventura F. Inhibition of C5AR1 impairs osteoclast mobilization and prevents bone loss. Mol Ther 2023; 31:2507-2523. [PMID: 37143324 PMCID: PMC10422003 DOI: 10.1016/j.ymthe.2023.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 12/22/2022] [Accepted: 04/28/2023] [Indexed: 05/06/2023] Open
Abstract
Age-related and chemotherapy-induced bone loss depends on cellular senescence and the cell secretory phenotype. However, the factors secreted in the senescent microenvironment that contribute to bone loss remain elusive. Here, we report a central role for the inflammatory alternative complement system in skeletal bone loss. Through transcriptomic analysis of bone samples, we identified complement factor D, a rate-limiting factor of the alternative pathway of complement, which is among the most responsive factors to chemotherapy or estrogen deficiency. We show that osteoblasts and osteocytes are major inducers of complement activation, while monocytes and osteoclasts are their primary targets. Genetic deletion of C5ar1, the receptor of the anaphylatoxin C5a, or treatment with a C5AR1 inhibitor reduced monocyte chemotaxis and osteoclast differentiation. Moreover, genetic deficiency or inhibition of C5AR1 partially prevented bone loss and osteoclastogenesis upon chemotherapy or ovariectomy. Altogether, these lines of evidence support the idea that inhibition of alternative complement pathways may have some therapeutic benefit in osteopenic disorders.
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Affiliation(s)
- Carolina Pimenta-Lopes
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Cristina Sánchez-de-Diego
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Alexandre Deber
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Andrea Egea-Cortés
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - José Antonio Valer
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Albert Alcalá
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Andrés Méndez-Lucas
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science & Technology, 08028 Barcelona, Spain; Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Jose Luis Rosa
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain
| | - Francesc Ventura
- Departament de Ciències Fisiològiques, Universitat de Barcelona, IDIBELL, 08907 L'Hospitalet de Llobregat, Spain.
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13
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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: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [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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14
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Wang Y, Ren L, Xu L, Wang J, Zhai J, Zhu G. Radiation Induces Bone Microenvironment Disruption by Activating the STING-TBK1 Pathway. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:1316. [PMID: 37512126 PMCID: PMC10386124 DOI: 10.3390/medicina59071316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/30/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023]
Abstract
Background and Objectives: Damage to normal bone tissue following therapeutic irradiation (IR) represents a significant concern, as IR-induced bone microenvironment disruption can cause bone loss and create a more favorable environment for tumor metastases. The aim of the present study was to explore the cellular regulatory mechanism of IR-induced bone microenvironment disruption to effectively prevent radiotherapy-associated adverse effects in the future. Materials and Methods: In this study, a mouse model of local IR was established via local irradiation of the left hind limb of BALB/c mice with 12 Gy X-rays, and an in vitro osteocyte (OCY) model was established by exposing osteocyte-like MLO-Y4 cells to 2, 4, and 8 Gy irradiation to analyze multicellular biological injuries and cellular senescence. Small interfering RNA (siRNA) transfection at the cellular level and a selective antagonist intervention C-176 at the animal level were used to explore the potential role of the stimulator of interferon genes (STING) on IR-induced bone microenvironment disruption. Results: The results showed that 12 Gy local IR induces multicellular dysfunction, manifested as ascension of OCYs exfoliation, activation of osteoclastogenesis, degeneration of osteogenesis and fate conversion of adipogenesis, as well as cellular senescence and altered senescence-associated secretory phenotype (SASP) secretion. Furthermore, the expression of STING was significantly elevated, both in the primary OCYs harvested from locally irradiated mice and in vitro irradiated MLO-Y4 cells, accompanied by the markedly upregulated levels of phosphorylated TANK-binding kinase 1 (P-TBK1), RANKL and sclerostin (SOST). STING-siRNA transfection in vitro restored IR-induced upregulated protein expression of P-TBK1 and RANKL, as well as the mRNA expression levels of inflammatory cytokines, such as IL-1α, IL-6 and NF-κB, accompanied by the alleviation of excessive osteoclastogenesis. Finally, administration of the STING inhibitor C-176 mitigated IR-induced activation of osteoclastogenesis and restraint of osteogenesis, ameliorating the IR-induced biological damage of OCYs, consistent with the inhibition of P-TBK1, RANKL and SOST. Conclusions: The STING-P-TBK1 signaling pathway plays a crucial role in the regulation of the secretion of inflammatory cytokines and osteoclastogenesis potential in IR-induced bone microenvironment disruption. The selective STING antagonist can be used to intervene to block the STING pathway and, thereby, repair IR-induced multicellular biological damage and mitigate the imbalance between osteoclastogenesis and osteoblastgenesis.
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Affiliation(s)
- Yuyang Wang
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
- Shanghai Municipal Center for Disease Control & Prevention, Shanghai 200051, China
| | - Li Ren
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Linshan Xu
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Jianping Wang
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Jianglong Zhai
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
| | - Guoying Zhu
- Institute of Radiation Medicine, Fudan University, 2094 Xietu Road, Shanghai 200032, China
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15
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Kitase Y, Prideaux M. Regulation of the Osteocyte Secretome with Aging and Disease. Calcif Tissue Int 2023; 113:48-67. [PMID: 37148298 DOI: 10.1007/s00223-023-01089-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 04/21/2023] [Indexed: 05/08/2023]
Abstract
As the most numerous and long-lived of all bone cells, osteocytes have essential functions in regulating skeletal health. Through the lacunar-canalicular system, secreted proteins from osteocytes can reach cells throughout the bone. Furthermore, the intimate connectivity between the lacunar-canalicular system and the bone vasculature allows for the transport of osteocyte-secreted factors into the circulation to reach the entire body. Local and endocrine osteocyte signaling regulates physiological processes such as bone remodeling, bone mechanoadaptation, and mineral homeostasis. However, these processes are disrupted by impaired osteocyte function induced by aging and disease. Dysfunctional osteocyte signaling is now associated with the pathogenesis of many disorders, including chronic kidney disease, cancer, diabetes mellitus, and periodontitis. In this review, we focus on the targeting of bone and extraskeletal tissues by the osteocyte secretome. In particular, we highlight the secreted osteocyte proteins, which are known to be dysregulated during aging and disease, and their roles during disease progression. We also discuss how therapeutic or genetic targeting of osteocyte-secreted proteins can improve both skeletal and systemic health.
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Affiliation(s)
- Yukiko Kitase
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA
| | - Matthew Prideaux
- Indiana Center for Musculoskeletal Health, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
- Department of Anatomy, Cell Biology and Physiology, School of Medicine, Indiana University, Indianapolis, IN, 46202, USA.
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16
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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: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [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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17
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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 : THE PREPRINT SERVER FOR BIOLOGY 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] [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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18
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Bolamperti S, Villa I, Rubinacci A. Bone remodeling: an operational process ensuring survival and bone mechanical competence. Bone Res 2022; 10:48. [PMID: 35851054 PMCID: PMC9293977 DOI: 10.1038/s41413-022-00219-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 05/02/2022] [Accepted: 05/15/2022] [Indexed: 12/12/2022] Open
Abstract
Bone remodeling replaces old and damaged bone with new bone through a sequence of cellular events occurring on the same surface without any change in bone shape. It was initially thought that the basic multicellular unit (BMU) responsible for bone remodeling consists of osteoclasts and osteoblasts functioning through a hierarchical sequence of events organized into distinct stages. However, recent discoveries have indicated that all bone cells participate in BMU formation by interacting both simultaneously and at different differentiation stages with their progenitors, other cells, and bone matrix constituents. Therefore, bone remodeling is currently considered a physiological outcome of continuous cellular operational processes optimized to confer a survival advantage. Bone remodeling defines the primary activities that BMUs need to perform to renew successfully bone structural units. Hence, this review summarizes the current understanding of bone remodeling and future research directions with the aim of providing a clinically relevant biological background with which to identify targets for therapeutic strategies in osteoporosis.
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Affiliation(s)
- Simona Bolamperti
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Isabella Villa
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy
| | - Alessandro Rubinacci
- Osteoporosis and Bone and Mineral Metabolism Unit, IRCCS San Raffaele Hospital, Via Olgettina 60, 20132, Milano, Italy.
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19
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Sfeir JG, Drake MT, Khosla S, Farr JN. Skeletal Aging. Mayo Clin Proc 2022; 97:1194-1208. [PMID: 35662432 PMCID: PMC9179169 DOI: 10.1016/j.mayocp.2022.03.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 03/01/2022] [Accepted: 03/14/2022] [Indexed: 10/18/2022]
Abstract
Aging represents the single greatest risk factor for chronic diseases, including osteoporosis, a skeletal fragility syndrome that increases fracture risk. Optimizing bone strength throughout life reduces fracture risk. Factors critical for bone strength include nutrition, physical activity, and vitamin D status, whereas unhealthy lifestyles, illnesses, and certain medications (eg, glucocorticoids) are detrimental. Hormonal status is another important determinant of skeletal health, with sex steroid concentrations, particularly estrogen, having major effects on bone remodeling. Aging exacerbates bone loss in both sexes and results in imbalanced bone resorption relative to formation; it is associated with increased marrow adiposity, osteoblast/osteocyte apoptosis, and accumulation of senescent cells. The mechanisms underlying skeletal aging are as diverse as the factors that determine the strength (and thus fragility) of bone. This review updates our current understanding of the epidemiology, pathophysiology, and treatment of osteoporosis and provides an overview of the underlying hallmark mechanisms that drive skeletal aging.
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Affiliation(s)
- Jad G Sfeir
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, MN
| | - Matthew T Drake
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, MN
| | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, MN
| | - Joshua N Farr
- Robert and Arlene Kogod Center on Aging and Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, MN.
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20
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Cui J, Shibata Y, Zhu T, Zhou J, Zhang J. Osteocytes in bone aging: Advances, challenges, and future perspectives. Ageing Res Rev 2022; 77:101608. [PMID: 35283289 DOI: 10.1016/j.arr.2022.101608] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/28/2022] [Accepted: 03/07/2022] [Indexed: 02/08/2023]
Abstract
Osteocytes play a critical role in maintaining bone homeostasis and in regulating skeletal response to hormones and mechanical loading. Substantial evidence have demonstrated that osteocytes and their lacunae exhibit morphological changes in aged bone, indicating the underlying involvement of osteocytes in bone aging. Notably, recent studies have deciphered aged osteocytes to have characteristics such as impaired mechanosensitivity, accumulated cellular senescence, dysfunctional perilacunar/canalicular remodeling, and degenerated lacuna-canalicular network. However, detailed molecular mechanisms of osteocytes remain unclear. Nonetheless, osteocyte transcriptomes analyzed via advanced RNA sequencing (RNA-seq) techniques have identified several bone aging-related genes and signaling pathways, such as Wnt, Bmp/TGF, and Jak-STAT. Moreover, inflammation, immune dysfunction, energy shortage, and impaired hormone responses possibly affect osteocytes in age-related bone deterioration. In this review, we summarize the hallmarks of aging bone and osteocytes and discuss osteocytic mechanisms in age-related bone loss and impaired bone quality. Furthermore, we provide insights into the challenges faced and their possible solutions when investigating osteocyte transcriptomes. We also highlight that single-cell RNA-seq can decode transcriptomic messages in aged osteocytes; therefore, this technique can promote novel single cell-based investigations in osteocytes once a well-established standardized protocol specific for osteocytes is developed. Interestingly, improved understanding of osteocytic mechanisms have helped identify promising targets and effective therapies for aging-related osteoporosis and fragile fractures.
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21
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Targeting Sirt1, AMPK, Nrf2, CK2, and Soluble Guanylate Cyclase with Nutraceuticals: A Practical Strategy for Preserving Bone Mass. Int J Mol Sci 2022; 23:ijms23094776. [PMID: 35563167 PMCID: PMC9104509 DOI: 10.3390/ijms23094776] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/19/2022] [Accepted: 04/25/2022] [Indexed: 12/15/2022] Open
Abstract
There is a vast pre-clinical literature suggesting that certain nutraceuticals have the potential to aid the preservation of bone mass in the context of estrogen withdrawal, glucocorticoid treatment, chronic inflammation, or aging. In an effort to bring some logical clarity to these findings, the signaling pathways regulating osteoblast, osteocyte, and osteoclast induction, activity, and survival are briefly reviewed in the present study. The focus is placed on the following factors: the mechanisms that induce and activate the RUNX2 transcription factor, a key driver of osteoblast differentiation and function; the promotion of autophagy and prevention of apoptosis in osteoblasts/osteoclasts; and the induction and activation of NFATc1, which promotes the expression of many proteins required for osteoclast-mediated osteolysis. This analysis suggests that the activation of sirtuin 1 (Sirt1), AMP-activated protein kinase (AMPK), the Nrf2 transcription factor, and soluble guanylate cyclase (sGC) can be expected to aid the maintenance of bone mass, whereas the inhibition of the serine kinase CK2 should also be protective in this regard. Fortuitously, nutraceuticals are available to address each of these targets. Sirt1 activation can be promoted with ferulic acid, N1-methylnicotinamide, melatonin, nicotinamide riboside, glucosamine, and thymoquinone. Berberine, such as the drug metformin, is a clinically useful activator of AMPK. Many agents, including lipoic acid, melatonin, thymoquinone, astaxanthin, and crucifera-derived sulforaphane, can promote Nrf2 activity. Pharmacological doses of biotin can directly stimulate sGC. Additionally, certain flavonols, notably quercetin, can inhibit CK2 in high nanomolar concentrations that may be clinically relevant. Many, though not all, of these agents have shown favorable effects on bone density and structure in rodent models of bone loss. Complex nutraceutical regimens providing a selection of these nutraceuticals in clinically meaningful doses may have an important potential for preserving bone health. Concurrent supplementation with taurine, N-acetylcysteine, vitamins D and K2, and minerals, including magnesium, zinc, and manganese, plus a diet naturally high in potassium, may also be helpful in this regard.
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22
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Kaya S, Schurman CA, Dole NS, Evans DS, Alliston T. Prioritization of Genes Relevant to Bone Fragility Through the Unbiased Integration of Aging Mouse Bone Transcriptomics and Human GWAS Analyses. J Bone Miner Res 2022; 37:804-817. [PMID: 35094432 PMCID: PMC9018503 DOI: 10.1002/jbmr.4516] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 12/20/2021] [Accepted: 01/17/2022] [Indexed: 11/10/2022]
Abstract
Identifying new genetic determinants of bone mineral density (BMD) and fracture promises to yield improved diagnostics and therapies for bone fragility. However, prioritizing candidate genes from genome-wide screens can be challenging. To overcome this challenge, we prioritized mouse genes that are differentially expressed in aging mouse bone based on whether their human homolog is associated with human BMD and/or fracture. Unbiased RNA-seq analysis of young and old male C57BL/6 mouse cortical bone identified 1499, 1685, and 5525 differentially expressed genes (DEGs) in 1, 2, and 2.5-year-old bone, relative to 2-month-old bone, respectively. Gene-based scores for heel ultrasound bone mineral density (eBMD) and fracture were estimated using published genome-wide association studies (GWAS) results of these traits in the UK Biobank. Enrichment analysis showed that mouse bone DEG sets for all three age groups, relative to young bone, are significantly enriched for eBMD, but only the oldest two DEG sets are enriched for fracture. Using gene-based scores, this approach prioritizes among thousands of DEGs by a factor of 5- to 100-fold, yielding 10 and 21 genes significantly associated with fracture in the two oldest groups of mouse DEGs. Though these genes were not the most differentially expressed, they included Sost, Lrp5, and others with well-established functions in bone. Several others have, as yet, unknown roles in the skeleton. Therefore, this study accelerates identification of new genetic determinants of bone fragility by prioritizing a clinically relevant and experimentally tractable number of candidate genes for functional analysis. Finally, we provide a website (www.mouse2human.org) to enable other researchers to easily apply our strategy. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Serra Kaya
- Department of Orthopaedic Surgery, University of California, San Francisco, CA
| | - Charles A. Schurman
- Department of Orthopaedic Surgery, University of California, San Francisco, CA
- UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA
| | - Neha S. Dole
- Department of Orthopaedic Surgery, University of California, San Francisco, CA
| | - Daniel S. Evans
- California Pacific Medical Center Research Institute, San Francisco, CA
| | - Tamara Alliston
- Department of Orthopaedic Surgery, University of California, San Francisco, CA
- UC Berkeley-UCSF Graduate Program in Bioengineering, San Francisco, CA
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23
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Abstract
Osteocytes, former osteoblasts encapsulated by mineralized bone matrix, are far from being passive and metabolically inactive bone cells. Instead, osteocytes are multifunctional and dynamic cells capable of integrating hormonal and mechanical signals and transmitting them to effector cells in bone and in distant tissues. Osteocytes are a major source of molecules that regulate bone homeostasis by integrating both mechanical cues and hormonal signals that coordinate the differentiation and function of osteoclasts and osteoblasts. Osteocyte function is altered in both rare and common bone diseases, suggesting that osteocyte dysfunction is directly involved in the pathophysiology of several disorders affecting the skeleton. Advances in osteocyte biology initiated the development of novel therapeutics interfering with osteocyte-secreted molecules. Moreover, osteocytes are targets and key distributors of biological signals mediating the beneficial effects of several bone therapeutics used in the clinic. Here we review the most recent discoveries in osteocyte biology demonstrating that osteocytes regulate bone homeostasis and bone marrow fat via paracrine signaling, influence body composition and energy metabolism via endocrine signaling, and contribute to the damaging effects of diabetes mellitus and hematologic and metastatic cancers in the skeleton.
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Affiliation(s)
- Jesus Delgado-Calle
- 1Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas,2Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Teresita Bellido
- 1Department of Physiology and Cell Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas,2Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas,3Central Arkansas Veterans Healthcare System, Little Rock, Arkansas
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24
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Hattori H, Takaoka K, Ueta M, Oshitani M, Tamaoka J, Noguchi K, Kishimoto H. Senescent RAW264.7 cells exhibit increased production of nitric oxide and release inducible nitric oxide synthase in exosomes. Mol Med Rep 2021; 24:681. [PMID: 34318909 DOI: 10.3892/mmr.2021.12320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 06/08/2021] [Indexed: 11/06/2022] Open
Abstract
Aging cells not only cease growing, but also secrete various proteins such as inflammatory cytokines. This secretory phenomenon is known as the senescence‑associated secretory phenotype (SASP). The aim of the present study was to elucidate the effects of senescence on the differentiation of osteoclast precursors (OCPs) and corresponding SASP. RAW264.7 cells were used as OCPs and were cultured to passage (P)5, P10 and P20. Cell proliferation assays, senescence‑associated β‑galactosidase staining and telomere length quantification were subsequently performed, and it was revealed that replicative senescence was induced at P20. In addition, the level of tartrate‑resistant acid phosphatase activity in P20 cells treated with receptor activator of nuclear factor‑κB ligand was significantly lower than that in P5 and P10 cells. The SASP factors interleukin‑6, tumour necrosis factor‑α and nitric oxide were significantly increased in P20 culture supernatants compared with those in P5 and P10 supernatants. Furthermore, the number of exosomes at P20 was increased compared with that at P5 and P10, and inducible nitric oxide synthase (iNOS) was expressed in exosomes at P20, but not in exosomes at P5. In conclusion, the present study revealed that senescent RAW264.7 cells exhibit increased expression of SASP factors and release iNOS in exosomes.
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Affiliation(s)
- Hirokazu Hattori
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
| | - Kazuki Takaoka
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
| | - Miho Ueta
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
| | - Masayuki Oshitani
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
| | - Joji Tamaoka
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
| | - Kazuma Noguchi
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
| | - Hiromitsu Kishimoto
- Department of Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo 663‑8501, Japan
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