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Trivanović D, Vujačić M, Labella R, Djordjević IO, Ćazić M, Chernak B, Jauković A. Molecular Deconvolution of Bone Marrow Adipose Tissue Interactions with Malignant Hematopoiesis: Potential for New Therapy Development. Curr Osteoporos Rep 2024:10.1007/s11914-024-00879-x. [PMID: 38922359 DOI: 10.1007/s11914-024-00879-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/18/2024] [Indexed: 06/27/2024]
Abstract
PURPOSE OF REVIEW Along with a strong impact on skeletal integrity, bone marrow adipose tissue (BMAT) is an important modulator of the adult hematopoietic system. This review will summarize the current knowledge on the causal relationship between bone marrow (BM) adipogenesis and the development and progression of hematologic malignancies. RECENT FINDINGS BM adipocytes (BMAds) support a number of processes promoting oncogenesis, including the evolution of clonal hematopoiesis, malignant cell survival, proliferation, angiogenesis, and chemoresistance. In addition, leukemic cells manipulate surrounding BMAds by promoting lipolysis and release of free fatty acids, which are then utilized by leukemic cells via β-oxidation. Therefore, limiting BM adipogenesis, blocking BMAd-derived adipokines, or lipid metabolism obstruction have been considered as potential treatment options for hematological malignancies. Leukemic stem cells rely heavily on BMAds within the structural BM microenvironment for necessary signals which foster disease progression. Further development of 3D constructs resembling BMAT at different skeletal regions are critical to better understand these relationships in geometric space and may provide essential insight into the development of hematologic malignancies within the BM niche. In turn, these mechanisms provide promising potential as novel approaches to targeting the microenvironment with new therapeutic strategies.
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Affiliation(s)
- Drenka Trivanović
- Group for Hematology and Stem Cells, Institute for Medical Research, National Institute of Republic of Serbia, University of Belgrade, 11000, Belgrade, Serbia.
| | - Marko Vujačić
- Institute for Orthopedy Banjica, 11000, Belgrade, Serbia
- School of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Rossella Labella
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Edward P. Evans Center for Myelodysplastic Syndromes, Columbia University Medical Center, New York, NY, USA
| | - Ivana Okić Djordjević
- Group for Hematology and Stem Cells, Institute for Medical Research, National Institute of Republic of Serbia, University of Belgrade, 11000, Belgrade, Serbia
| | - Marija Ćazić
- Department of Hematology and Oncology, University Children's Hospital Tiršova, 11000, Belgrade, Serbia
| | - Brian Chernak
- Division of Hematology/Oncology, Columbia University, New York, NY, USA
| | - Aleksandra Jauković
- Group for Hematology and Stem Cells, Institute for Medical Research, National Institute of Republic of Serbia, University of Belgrade, 11000, Belgrade, Serbia
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Sen B, Xie Z, Thomas MD, Pattenden SG, Howard S, McGrath C, Styner M, Uzer G, Furey TS, Rubin J. Nuclear actin structure regulates chromatin accessibility. Nat Commun 2024; 15:4095. [PMID: 38750021 PMCID: PMC11096319 DOI: 10.1038/s41467-024-48580-y] [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: 08/28/2023] [Accepted: 05/07/2024] [Indexed: 05/18/2024] Open
Abstract
Polymerized β-actin may provide a structural basis for chromatin accessibility and actin transport into the nucleus can guide mesenchymal stem cell (MSC) differentiation. Using MSC, we show that using CK666 to inhibit Arp2/3 directed secondary actin branching results in decreased nuclear actin structure, and significantly alters chromatin access measured with ATACseq at 24 h. The ATAC-seq results due to CK666 are distinct from those caused by cytochalasin D (CytoD), which enhances nuclear actin structure. In addition, nuclear visualization shows Arp2/3 inhibition decreases pericentric H3K9me3 marks. CytoD, alternatively, induces redistribution of H3K27me3 marks centrally. Such alterations in chromatin landscape are consistent with differential gene expression associated with distinctive differentiation patterns. Further, knockdown of the non-enzymatic monomeric actin binding protein, Arp4, leads to extensive chromatin unpacking, but only a modest increase in transcription, indicating an active role for actin-Arp4 in transcription. These data indicate that dynamic actin remodeling can regulate chromatin interactions.
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Affiliation(s)
- Buer Sen
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Zhihui Xie
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Michelle D Thomas
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Samantha G Pattenden
- Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Sean Howard
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Cody McGrath
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Maya Styner
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Gunes Uzer
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID, USA
| | - Terrence S Furey
- Departments of Genetics and Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
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Little-Letsinger SE, Hamilton SE. Leveraging mice with diverse microbial exposures for advances in osteoimmunology. Front Endocrinol (Lausanne) 2023; 14:1168552. [PMID: 37251680 PMCID: PMC10210590 DOI: 10.3389/fendo.2023.1168552] [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: 02/17/2023] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
The skeletal and immune systems are intricately intertwined within the bone marrow microenvironment, a field of study termed osteoimmunology. Osteoimmune interactions are key players in bone homeostasis and remodeling. Despite the critical role of the immune system in bone health, virtually all animal research in osteoimmunology, and more broadly bone biology, relies on organisms with naïve immune systems. Drawing on insights from osteoimmunology, evolutionary anthropology, and immunology, this perspective proposes the use of a novel translational model: the dirty mouse. Dirty mice, characterized by diverse exposures to commensal and pathogenic microbes, have mature immune systems comparable to adult humans, while the naïve immune system of specific-pathogen free mice is akin to a neonate. Investigation into the dirty mouse model will likely yield important insights in our understanding of bone diseases and disorders. A high benefit of this model is expected for diseases known to have a connection between overactivation of the immune system and negative bone outcomes, including aging and osteoporosis, rheumatoid arthritis, HIV/AIDS, obesity and diabetes, bone marrow metastases, and bone cancers.
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Affiliation(s)
| | - Sara E. Hamilton
- Department of Laboratory Medicine and Pathology, Center for Immunology, University of Minnesota, Minneapolis, MN, United States
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Dent E, Daly RM, Hoogendijk EO, Scott D. Exercise to Prevent and Manage Frailty and Fragility Fractures. Curr Osteoporos Rep 2023; 21:205-215. [PMID: 36976491 PMCID: PMC10105671 DOI: 10.1007/s11914-023-00777-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/30/2023] [Indexed: 03/29/2023]
Abstract
PURPOSE OF REVIEW This review identifies exercise-based recommendations to prevent and manage frailty and fragility fractures from current clinical practice guidelines. We also critically assess recently published literature in relation to exercise interventions to mitigate frailty and fragility fractures. RECENT FINDINGS Most guidelines presented similar recommendations that included the prescription of individually tailored, multicomponent exercise programs, discouragement of prolonged sitting and inactivity, and combining exercise with optimal nutrition. To target frailty, guidelines recommend supervised progressive resistance training (PRT). For osteoporosis and fragility fractures, exercise should include weight-bearing impact activities and PRT to target bone mineral density (BMD) at the hip and spine, and also incorporate balance and mobility training, posture exercises, and functional exercise relevant to activities of daily living to reduce falls risk. Walking as a singular intervention has limited benefits for frailty and fragility fracture prevention and management. Current evidence-based clinical practice guidelines for frailty, osteoporosis, and fracture prevention recommend a multifaceted and targeted approach to optimise muscle mass, strength, power, and functional mobility as well as BMD.
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Affiliation(s)
- Elsa Dent
- Research Centre for Public Health, Equity & Human Flourishing, Torrens University Australia, Adelaide, SA, Australia
| | - Robin M Daly
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Emiel O Hoogendijk
- Department of Epidemiology & Data Science, Amsterdam UMC - Location VU University Medical Center, Amsterdam, the Netherlands.
- Department of General Practice, Amsterdam UMC - Location VU University Medical Center, Amsterdam, the Netherlands.
- Amsterdam Public Health Research Institute, Ageing and Later Life Research Program, Amsterdam, the Netherlands.
| | - David Scott
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
- Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Australia
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Deriggi-Pisani GF, Stotzer US, Marqueti RC, Rodrigues MFC, Biffe BG, Silva KA, Fabricio V, Rosen CJ, Selistre-de-Araujo HS. Role of resistance training in bone macro and micro damages in an estrogen absence animal model. Life Sci 2023; 317:121417. [PMID: 36690246 DOI: 10.1016/j.lfs.2023.121417] [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: 10/07/2022] [Revised: 12/20/2022] [Accepted: 01/17/2023] [Indexed: 01/22/2023]
Abstract
AIMS We evaluated the effects of resistance training (RT) on bone properties, morphology, and bone extracellular matrix (ECM) remodeling markers in an ovariectomy (OVX) rat model. MAIN METHODS Thirty-six female rats were divided into four groups: sham sedentary, OVX sedentary, sham RT, and OVX RT. Rats performed RT for ten weeks, during which they climbed a ladder with progressive loads attached to the tail. Tibias were stored for dual-energy X-ray densitometry (DXA), micro-computed tomography (micro-CT), and biomechanical, biophysical, and biochemical analysis. Femurs were stored for morphological, gene expression, and gelatin zymography analysis. KEY FINDINGS OVX decreased bone mineral density, stiffness, maximal load, and calcium content, which was reversed by RT. The trabecular number, connectivity, and MMP-13 gene expression decreased in OVX groups. Furthermore, OVX increased run-related transcription factor-2 (RUNX-2) and osteoprotegerin (OPG) gene expression, and increased the number of adipocytes in bone marrow and MMP-2 activity. SIGNIFICANCE RT was efficient in preventing or reversing changes in bone biomechanical properties in OVX groups, improving fracture load and resilience, which is relevant to prevent fractures. On the other hand, RT did not decrease the number of bone adipocytes in the OVX-RT group. However, RT was efficient for increasing trabecular thickness and cortical bone volume, which improved bone resistance. Our findings provide further insights into the mechanisms involved in the role of RT in OVX damage protection.
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Affiliation(s)
- Graziéle F Deriggi-Pisani
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil.
| | - Uliana S Stotzer
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Rita C Marqueti
- Laboratório de Análises Moleculares - LAM, Faculdade de Ceilândia, Universidade de Brasília (UnB), Distrito Federal, Brazil
| | - Maria F C Rodrigues
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Bruna G Biffe
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Karina A Silva
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Victor Fabricio
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, Maine, United States
| | - Heloisa Sobreiro Selistre-de-Araujo
- Laboratório de Bioquímica e Biologia Molecular, Departamento de Ciências Fisiológicas, Universidade Federal de São Carlos (UFSCar), São Carlos, São Paulo, Brazil
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Shu JB, Kim TY. Bone marrow adiposity in diabetes and clinical interventions. Curr Opin Endocrinol Diabetes Obes 2022; 29:303-309. [PMID: 35776685 DOI: 10.1097/med.0000000000000741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE OF REVIEW This study aims to review bone marrow adipose tissue (BMAT) changes in people with diabetes, contributing factors, and interventions. RECENT FINDINGS In type 1 diabetes (T1D), BMAT levels are similar to healthy controls, although few studies have been performed. In type 2 diabetes (T2D), both BMAT content and composition appear altered, and recent bone histomorphometry data suggests increased BMAT is both through adipocyte hyperplasia and hypertrophy. Position emission tomography scanning suggests BMAT is a major source of basal glucose uptake. BMAT is responsive to metabolic interventions. SUMMARY BMAT is a unique fat depot that is influenced by metabolic factors and proposed to negatively affect the skeleton. BMAT alterations are more consistently seen in T2D compared to T1D. Interventions such as thiazolidinedione treatment may increase BMAT, whereas metformin treatment, weight loss, and exercise may decrease BMAT. Further understanding of the role of BMAT will provide insight into the pathogenesis of diabetic bone disease and could lead to targeted preventive and therapeutic strategies.
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Affiliation(s)
- Jessica B Shu
- University of California, San Francisco and the San Francisco VA Health Care System, San Francisco, California, USA
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Lu K, Shi TS, Shen SY, Shi Y, Gao HL, Wu J, Lu X, Gao X, Ju HX, Wang W, Cao Y, Chen D, Li CJ, Xue B, Jiang Q. Defects in a liver-bone axis contribute to hepatic osteodystrophy disease progression. Cell Metab 2022; 34:441-457.e7. [PMID: 35235775 DOI: 10.1016/j.cmet.2022.02.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 11/26/2021] [Accepted: 02/08/2022] [Indexed: 12/12/2022]
Abstract
Hepatic osteodystrophy (HOD) is a metabolic bone disease that is often associated with chronic liver disease and is marked by bone loss. Here, we demonstrate that hepatic expression of the phosphatase PP2Acα is upregulated during HOD, leading to the downregulation of expression of the hepatokine lecithin-cholesterol acyltransferase (LCAT). Loss of LCAT function markedly exacerbates the bone loss phenotype of HOD in mice. In addition, we found that alterations in cholesterol levels are involved in the regulation of osteoblast and osteoclast activities. We also found that LCAT improves liver function and relieves liver fibrosis in the mouse HOD model by promoting reversal of cholesterol transport from the bone to the liver. In summary, defects in a liver-bone axis occur during HOD that can be targeted to ameliorate disease progression.
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Affiliation(s)
- Ke Lu
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing 210008, China; Branch of National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, 321 Zhongshan Road, Nanjing 210008, China; Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Tian-Shu Shi
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing 210008, China; Branch of National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, 321 Zhongshan Road, Nanjing 210008, China
| | - Si-Yu Shen
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing 210008, China; Branch of National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, 321 Zhongshan Road, Nanjing 210008, China
| | - Yong Shi
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing 210008, China; Branch of National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, 321 Zhongshan Road, Nanjing 210008, China
| | - Hong-Liang Gao
- Core Laboratory, Sir Run Run Hospital, Nanjing Medical University, Nanjing 211166, China
| | - Jing Wu
- Core Laboratory, Sir Run Run Hospital, Nanjing Medical University, Nanjing 211166, China
| | - Xiang Lu
- Core Laboratory, Sir Run Run Hospital, Nanjing Medical University, Nanjing 211166, China
| | - Xiang Gao
- Model Animal Research Center of Nanjing University, Xuefu Road, Nanjing 210032, China
| | - Huang-Xian Ju
- State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210023, China
| | - Wei Wang
- National Laboratory of Solid-State Microstructures, Department of Physics, Nanjing University, Nanjing 210093, China
| | - Yi Cao
- National Laboratory of Solid-State Microstructures, Department of Physics, Nanjing University, Nanjing 210093, China
| | - Di Chen
- Faculty of Pharmaceutical Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
| | - Chao-Jun Li
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of the Medical School, Nanjing University, Nanjing 210093, China; State Key Laboratory of Reproductive Medicine and China International Joint Research Center on Environment and Human Health, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Bin Xue
- Core Laboratory, Sir Run Run Hospital, Nanjing Medical University, Nanjing 211166, China.
| | - Qing Jiang
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Sports Medicine and Adult Reconstructive Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing 210008, China; Branch of National Clinical Research Center for Orthopedics, Sports Medicine and Rehabilitation, 321 Zhongshan Road, Nanjing 210008, China.
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Little-Letsinger SE, Rubin J, Diekman B, Rubin CT, McGrath C, Pagnotti GM, Klett EL, Styner M. Exercise to Mend Aged-tissue Crosstalk in Bone Targeting Osteoporosis & Osteoarthritis. Semin Cell Dev Biol 2022; 123:22-35. [PMID: 34489173 PMCID: PMC8840966 DOI: 10.1016/j.semcdb.2021.08.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 12/16/2022]
Abstract
Aging induces alterations in bone structure and strength through a multitude of processes, exacerbating common aging- related diseases like osteoporosis and osteoarthritis. Cellular hallmarks of aging are examined, as related to bone and the marrow microenvironment, and ways in which these might contribute to a variety of age-related perturbations in osteoblasts, osteocytes, marrow adipocytes, chondrocytes, osteoclasts, and their respective progenitors. Cellular senescence, stem cell exhaustion, mitochondrial dysfunction, epigenetic and intracellular communication changes are central pathways and recognized as associated and potentially causal in aging. We focus on these in musculoskeletal system and highlight knowledge gaps in the literature regarding cellular and tissue crosstalk in bone, cartilage, and the bone marrow niche. While senolytics have been utilized to target aging pathways, here we propose non-pharmacologic, exercise-based interventions as prospective "senolytics" against aging effects on the skeleton. Increased bone mass and delayed onset or progression of osteoporosis and osteoarthritis are some of the recognized benefits of regular exercise across the lifespan. Further investigation is needed to delineate how cellular indicators of aging manifest in bone and the marrow niche and how altered cellular and tissue crosstalk impact disease progression, as well as consideration of exercise as a therapeutic modality, as a means to enhance discovery of bone-targeted therapies.
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Affiliation(s)
- SE Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill
| | - J Rubin
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill,North Carolina Diabetes Research Center (NCDRC), University of North Carolina at Chapel Hill,Department of Medicine, Thurston Arthritis Research Center (TARC), University of North Carolina at Chapel Hill
| | - B Diekman
- Department of Medicine, Thurston Arthritis Research Center (TARC), University of North Carolina at Chapel Hill,Joint Departments of Biomedical Engineering NC State & University of North Carolina at Chapel Hill
| | - CT Rubin
- Department of Biomedical Engineering, State University of New York at Stony Brook
| | - C McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill
| | - GM Pagnotti
- Dept of Endocrine, Neoplasia, and Hormonal Disorders, University Texas MD Anderson Cancer Center, Houston
| | - EL Klett
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill,Department of Nutrition, School of Public Health, University of North Carolina at Chapel Hill
| | - M Styner
- Department of Medicine, Division of Endocrinology & Metabolism, University of North Carolina at Chapel Hill,North Carolina Diabetes Research Center (NCDRC), University of North Carolina at Chapel Hill,Department of Medicine, Thurston Arthritis Research Center (TARC), University of North Carolina at Chapel Hill
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Rubin J, van Wijnen AJ, Uzer G. Architectural control of mesenchymal stem cell phenotype through nuclear actin. Nucleus 2022; 13:35-48. [PMID: 35133922 PMCID: PMC8837231 DOI: 10.1080/19491034.2022.2029297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
There is growing appreciation that architectural components of the nucleus regulate gene accessibility by altering chromatin organization. While nuclear membrane connector proteins link the mechanosensitive actin cytoskeleton to the nucleoskeleton, actin’s contribution to the inner architecture of the nucleus remains enigmatic. Control of actin transport into the nucleus, plus the presence of proteins that control actin structure (the actin tool-box) within the nucleus, suggests that nuclear actin may support biomechanical regulation of gene expression. Cellular actin structure is mechanoresponsive: actin cables generated through forces experienced at the plasma membrane transmit force into the nucleus. We posit that dynamic actin remodeling in response to such biomechanical cues provides a novel level of structural control over the epigenetic landscape. We here propose to bring awareness to the fact that mechanical forces can promote actin transfer into the nucleus and control structural arrangements as illustrated in mesenchymal stem cells, thereby modulating lineage commitment.
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Affiliation(s)
- Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andre J van Wijnen
- Department of Biochemistry, University of Vermont Medical School, Burlington, Vt, USA
| | - Gunes Uzer
- Department of Mechanical & Biomedical Engineering, Boise State University, Boise, ID, USA
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10
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McGrath C, Little-Letsinger SE, Sankaran JS, Sen B, Xie Z, Styner MA, Zong X, Chen W, Rubin J, Klett EL, Coleman RA, Styner M. Exercise Increases Bone in SEIPIN Deficient Lipodystrophy, Despite Low Marrow Adiposity. Front Endocrinol (Lausanne) 2021; 12:782194. [PMID: 35145475 PMCID: PMC8822583 DOI: 10.3389/fendo.2021.782194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/20/2021] [Indexed: 01/12/2023] Open
Abstract
Exercise, typically beneficial for skeletal health, has not yet been studied in lipodystrophy, a condition characterized by paucity of white adipose tissue, with eventual diabetes, and steatosis. We applied a mouse model of global deficiency of Bscl2 (SEIPIN), required for lipid droplet formation. Male twelve-week-old B6 knockouts (KO) and wild type (WT) littermates were assigned six-weeks of voluntary, running exercise (E) versus non-exercise (N=5-8). KO weighed 14% less than WT (p=0.01) and exhibited an absence of epididymal adipose tissue; KO liver Plin1 via qPCR was 9-fold that of WT (p=0.04), consistent with steatosis. Bone marrow adipose tissue (BMAT), unlike white adipose, was measurable, although 40.5% lower in KO vs WT (p=0.0003) via 9.4T MRI/advanced image analysis. SEIPIN ablation's most notable effect marrow adiposity was in the proximal femoral diaphysis (-56% KO vs WT, p=0.005), with relative preservation in KO-distal-femur. Bone via μCT was preserved in SEIPIN KO, though some quality parameters were attenuated. Running distance, speed, and time were comparable in KO and WT. Exercise reduced weight (-24% WT-E vs WT p<0.001) but not in KO. Notably, exercise increased trabecular BV/TV in both (+31%, KO-E vs KO, p=0.004; +14%, WT-E vs WT, p=0.006). The presence and distribution of BMAT in SEIPIN KO, though lower than WT, is unexpected and points to a uniqueness of this depot. That trabecular bone increases were achievable in both KO and WT, despite a difference in BMAT quantity/distribution, points to potential metabolic flexibility during exercise-induced skeletal anabolism.
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Affiliation(s)
- Cody McGrath
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Sarah E. Little-Letsinger
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Jeyantt Srinivas Sankaran
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Buer Sen
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Zhihui Xie
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Martin A. Styner
- Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Xiaopeng Zong
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, United States
| | - Janet Rubin
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
| | - Eric L. Klett
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Rosalind A. Coleman
- Department of Nutrition, Gillings School of Global Public Health, UNC, Chapel Hill, NC, United States
| | - Maya Styner
- Department of Medicine, Division of Endocrinology & Metabolism, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- North Carolina Diabetes Research Center (NCDRC), Chapel Hill, NC, United States
- *Correspondence: Maya Styner,
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