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Nelson TA, Tommasini S, Fretz JA. Deletion of the transcription factor EBF1 in perivascular stroma disrupts skeletal homeostasis and precipitates premature aging of the marrow microenvironment. Bone 2024; 187:117198. [PMID: 39002837 DOI: 10.1016/j.bone.2024.117198] [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: 02/13/2024] [Revised: 06/26/2024] [Accepted: 07/07/2024] [Indexed: 07/15/2024]
Abstract
Early B cell factor 1 (EBF1) is a transcription factor expressed by multiple lineages of stromal cells within the bone marrow. While cultures of Ebf1-deficient cells have been demonstrated to have impaired differentiation into either the osteoblast or adipogenic lineage in vitro by several groups, in vivo there has been a nominal consequence of the loss of EBF1 on skeletal development. In this study we used Prx-cre driven deletion of Ebf1 to eliminate EBF1 from the entire mesenchymal lineage of the skeleton and resolve this discrepancy. We report here that EBF1 is expressed primarily in the Mesenchymal Stem and Progenitor Cell (MSPC)-Adipo, MSPC-Osteo, and the Early Mesenchymal Progenitors, and that loss of EBF1 has a plethora of consequences to maintenance of the skeleton throughout adulthood. Stroma from the Prx-cre;Ebf1fl/fl bones had impaired osteogenic differentiation, an age-dependent loss of CFU-F, and elevated senescence accompanying Ebf1-deletion. New bone formation was reduced after 3 months, and resulted in a quiescent bone environment with fewer osteoblasts and an accompanied reduction in osteoclast-mediated remodeling. Consequently, bones were less ductile at a younger age, and deletion of EBF1 dramatically impaired fracture repair. Disruption of EBF1 in perivascular populations also rearranged the vascular network within these bones and disrupted cytokine signaling from key hematopoietic niches resulting in anemia, reductions in B cells, and myeloid skewing of marrow hematopoietic lineages. Mechanistically we observed disrupted BMP signaling within Ebf1-deficient progenitors with reduced SMAD1-phosphorylation, and elevated secretion of the soluble BMP-inhibitor Gremlin from the MSPC-Adipo cells. Ebf1-deficient progenitors also exhibited posttranslational suppression of glucocorticoid receptor expression. Together, these results suggest that EBF1 signaling is required for mesenchymal progenitor mobilization to maintain the adult skeleton, and that the primary action of EBF1 in the early mesenchymal lineage is to promote proliferation, and differentiation of these perivascular cells to sustain a healthy tissue.
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Affiliation(s)
- Tracy A Nelson
- Yale School of Medicine, Department of Orthopaedics and Rehabilitation, New Haven, CT 06510, United States of America
| | - Stephen Tommasini
- Yale School of Medicine, Department of Orthopaedics and Rehabilitation, New Haven, CT 06510, United States of America
| | - Jackie A Fretz
- Yale School of Medicine, Department of Orthopaedics and Rehabilitation, New Haven, CT 06510, United States of America.
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2
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Tuladhar A, Shaver JC, McGee WA, Yu K, Dorn J, Horne JL, Alhamad DW, Hagan ML, Cooley MA, Zhong R, Bollag W, Johnson M, Hamrick MW, McGee-Lawrence ME. Prkd1 regulates the formation and repair of plasma membrane disruptions (PMD) in osteocytes. Bone 2024; 186:117147. [PMID: 38866124 PMCID: PMC11246118 DOI: 10.1016/j.bone.2024.117147] [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: 01/24/2024] [Revised: 05/21/2024] [Accepted: 06/03/2024] [Indexed: 06/14/2024]
Abstract
We and others have seen that osteocytes sense high-impact osteogenic mechanical loading via transient plasma membrane disruptions (PMDs) which initiate downstream mechanotransduction. However, a PMD must be repaired for the cell to survive this wounding event. Previous work suggested that the protein Prkd1 (also known as PKCμ) may be a critical component of this PMD repair process, but the specific role of Prkd1 in osteocyte mechanobiology had not yet been tested. We treated MLO-Y4 osteocytes with Prkd1 inhibitors (Go6976, kbNB 142-70, staurosporine) and generated an osteocyte-targeted (Dmp1-Cre) Prkd1 conditional knockout (CKO) mouse. PMD repair rate was measured via laser wounding and FM1-43 dye uptake, PMD formation and post-wounding survival were assessed via fluid flow shear stress (50 dyn/cm2), and in vitro osteocyte mechanotransduction was assessed via measurement of calcium signaling. To test the role of osteocyte Prkd1 in vivo, Prkd1 CKO and their wildtype (WT) littermates were subjected to 2 weeks of unilateral axial tibial loading and loading-induced changes in cortical bone mineral density, geometry, and formation were measured. Prkd1 inhibition or genetic deletion slowed osteocyte PMD repair rate and impaired post-wounding cell survival. These effects could largely be rescued by treating osteocytes with the FDA-approved synthetic copolymer Poloxamer 188 (P188), which was previously shown to facilitate membrane resealing and improve efficiency in the repair rate of PMD in skeletal muscle myocytes. In vivo, while both WT and Prkd1 CKO mice demonstrated anabolic responses to tibial loading, the magnitude of loading-induced increases in tibial BMD, cortical thickness, and periosteal mineralizing surface were blunted in Prkd1 CKO as compared to WT mice. Prkd1 CKO mice also tended to show a smaller relative difference in the number of osteocyte PMD in loaded limbs and showed greater lacunar vacancy, suggestive of impaired post-wounding osteocyte survival. While P188 treatment rescued loading-induced increases in BMD in the Prkd1 CKO mice, it surprisingly further suppressed loading-induced increases in cortical bone thickness and cortical bone formation. Taken together, these data suggest that Prkd1 may play a pivotal role in the regulation and repair of the PMD response in osteocytes and support the idea that PMD repair processes can be pharmacologically targeted to modulate downstream responses, but suggest limited utility of PMD repair-promoting P188 in improving bone anabolic responses to loading.
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Affiliation(s)
- Anik Tuladhar
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Joseph C Shaver
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Wesley A McGee
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Kanglun Yu
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Jennifer Dorn
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - J Luke Horne
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Dima W Alhamad
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Mackenzie L Hagan
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Marion A Cooley
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Roger Zhong
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at AugustaUniversity, Augusta, GA, United States of America
| | - Wendy Bollag
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, United States of America; Charlie Norwood VA Medical Center, Augusta, GA, United States of America
| | - Maribeth Johnson
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia at AugustaUniversity, Augusta, GA, United States of America
| | - Mark W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States of America.
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3
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Mejía-Barradas CM, Amador-Martínez A, Lara-Padilla E, Cárdenas-Rodríguez N, Ignacio-Mejía I, Martínez-López V, Ibañez-Cervantes G, Picado-Garcia ODJ, Domínguez B, Bandala C. Effects of Selective and Nonselective Beta Blockers on Bone Mineral Density in Mexican Patients with Breast Cancer. Cancers (Basel) 2024; 16:2891. [PMID: 39199661 PMCID: PMC11352457 DOI: 10.3390/cancers16162891] [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: 07/03/2024] [Revised: 08/06/2024] [Accepted: 08/16/2024] [Indexed: 09/01/2024] Open
Abstract
Breast cancer (BCa) is related to chronic stress and can reduce the bone mineral density (BMD) through neurochemicals related to beta-adrenergic receptor (ADRB) 1 and 2. Selective beta blockers (sBBs) and nonselective beta blockers (nsBBs) are used to treat systemic arterial hypertension (SAH) and may have osteoprotective effects, as they inhibit ADRBs. To evaluate the effects of sBBs and nsBBs on the BMD of Mexican patients with BCa. A retrospective study was conducted. We included 191 Mexican women with BCa without SAH and with SAH treated with nsBBs, sBBs, and diuretics. BMD was evaluated using a bone density scan (DEX scan). A greater average BMD (p < 0.05) was observed in patients with prior treatment with both nsBBs and sBBs (0.54 ± 0.94 and -0.44 ± 1.22, respectively) compared to patients treated with diuretics or without SAH (-1.73 ± 0.83 and -1.22 ± 0.98, respectively). Regarding the diagnosis of osteoporosis/osteopenia, no cases were observed in patients treated with nsBBs, whereas 5.6% of the patients treated with sBBs presented osteopenia. A total of 23.1% and 10.6% patients managed with diuretics or without treatment presented with osteoporosis and 61.5% and 48% patients managed with loop diuretics and without treatment presented with osteopenia, respectively (p < 0.05). Treatment with nsBBs is a promising option for the prevention and management of osteoporosis/osteopenia in Mexican patients with BCa; however, further prospective studies are needed.
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Affiliation(s)
- César Miguel Mejía-Barradas
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico; (C.M.M.-B.); (E.L.-P.); (G.I.-C.), (B.D.)
| | - Ana Amador-Martínez
- Departamento de Radiología e Imagen, Centro Médico ABC, Mexico City 01120, Mexico;
| | - Eleazar Lara-Padilla
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico; (C.M.M.-B.); (E.L.-P.); (G.I.-C.), (B.D.)
| | | | - Iván Ignacio-Mejía
- Laboratorio de Medicina Traslacional, Escuela Militar de Graduados en Sanidad, Universidad Del Ejército y Fuerza Aérea, Mexico City 11200, Mexico;
| | - Valentín Martínez-López
- Unidad de Ingeniería de Tejidos, Terapia Celular y Medicina Regenerativa, Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra, Mexico City 14389, Mexico;
| | - Gabriela Ibañez-Cervantes
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico; (C.M.M.-B.); (E.L.-P.); (G.I.-C.), (B.D.)
- División de Investigación, Hospital Juárez de México, Mexico City 07760, Mexico
| | | | - Brayan Domínguez
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico; (C.M.M.-B.); (E.L.-P.); (G.I.-C.), (B.D.)
| | - Cindy Bandala
- Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City 11340, Mexico; (C.M.M.-B.); (E.L.-P.); (G.I.-C.), (B.D.)
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4
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Peng Y, Zhong Z, Huang C, Wang W. The effects of popular diets on bone health in the past decade: a narrative review. Front Endocrinol (Lausanne) 2024; 14:1287140. [PMID: 38665424 PMCID: PMC11044027 DOI: 10.3389/fendo.2023.1287140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/14/2023] [Indexed: 04/28/2024] Open
Abstract
Bone health encompasses not only bone mineral density but also bone architecture and mechanical properties that can impact bone strength. While specific dietary interventions have been proposed to treat various diseases such as obesity and diabetes, their effects on bone health remain unclear. The aim of this review is to examine literature published in the past decade, summarize the effects of currently popular diets on bone health, elucidate underlying mechanisms, and provide solutions to neutralize the side effects. The diets discussed in this review include a ketogenic diet (KD), a Mediterranean diet (MD), caloric restriction (CR), a high-protein diet (HP), and intermittent fasting (IF). Although detrimental effects on bone health have been noticed in the KD and CR diets, it is still controversial, while the MD and HP diets have shown protective effects, and the effects of IF diets are still uncertain. The mechanism of these effects and the attenuation methods have gained attention and have been discussed in recent years: the KD diet interrupts energy balance and calcium metabolism, which reduces bone quality. Ginsenoside-Rb2, metformin, and simvastatin have been shown to attenuate bone loss during KD. The CR diet influences energy imbalance, glucocorticoid levels, and adipose tissue, causing bone loss. Adequate vitamin D and calcium supplementation and exercise training can attenuate these effects. The olive oil in the MD may be an effective component that protects bone health. HP diets also have components that protect bone health, but their mechanism requires further investigation. In IF, animal studies have shown detrimental effects on bone health, while human studies have not. Therefore, the effects of diets on bone health vary accordingly.
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Affiliation(s)
- Yue Peng
- China Japan Friendship Hospital (Institute of Clinical Medical Sciences), Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zikang Zhong
- China Japan Friendship Hospital (Institute of Clinical Medical Sciences), Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Cheng Huang
- Department of Orthopaedic Surgery, China Japan Friendship Hospital, Beijing, China
| | - Weiguo Wang
- Department of Orthopaedic Surgery, China Japan Friendship Hospital, Beijing, China
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5
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Xiao Y, Han C, Wang Y, Zhang X, Bao R, Li Y, Chen H, Hu B, Liu S. Interoceptive regulation of skeletal tissue homeostasis and repair. Bone Res 2023; 11:48. [PMID: 37669953 PMCID: PMC10480189 DOI: 10.1038/s41413-023-00285-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 05/08/2023] [Accepted: 06/22/2023] [Indexed: 09/07/2023] Open
Abstract
Recent studies have determined that the nervous system can sense and respond to signals from skeletal tissue, a process known as skeletal interoception, which is crucial for maintaining bone homeostasis. The hypothalamus, located in the central nervous system (CNS), plays a key role in processing interoceptive signals and regulating bone homeostasis through the autonomic nervous system, neuropeptide release, and neuroendocrine mechanisms. These mechanisms control the differentiation of mesenchymal stem cells into osteoblasts (OBs), the activation of osteoclasts (OCs), and the functional activities of bone cells. Sensory nerves extensively innervate skeletal tissues, facilitating the transmission of interoceptive signals to the CNS. This review provides a comprehensive overview of current research on the generation and coordination of skeletal interoceptive signals by the CNS to maintain bone homeostasis and their potential role in pathological conditions. The findings expand our understanding of intersystem communication in bone biology and may have implications for developing novel therapeutic strategies for bone diseases.
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Affiliation(s)
- Yao Xiao
- Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai, 200233, PR China
| | - Changhao Han
- Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai, 200233, PR China
| | - Yunhao Wang
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, 200003, PR China
| | - Xinshu Zhang
- Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai, 200233, PR China
| | - Rong Bao
- Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai, 200233, PR China
| | - Yuange Li
- Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai, 200233, PR China
| | - Huajiang Chen
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, 200003, PR China
| | - Bo Hu
- Spine Center, Department of Orthopedics, Changzheng Hospital, Naval Medical University, Shanghai, 200003, PR China.
| | - Shen Liu
- Department of Orthopaedics, Shanghai Jiao Tong University School of Medicine Affiliated Sixth People's Hospital, 600 Yishan Rd, Shanghai, 200233, PR China.
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6
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Bensreti H, Yu K, Alhamad DW, Shaver J, Kaiser H, Zhong R, Whichard WC, Parker E, Grater L, Faith H, Johnson M, Cooley MA, Fulzele S, Hill WD, Isales CM, Hamrick MW, McGee-Lawrence ME. Orchiectomy sensitizes cortical bone in male mice to the harmful effects of kynurenine. Bone 2023; 173:116811. [PMID: 37244427 PMCID: PMC10330684 DOI: 10.1016/j.bone.2023.116811] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 05/29/2023]
Abstract
Kynurenine (Kyn) is a tryptophan metabolite that increases with age and promotes musculoskeletal dysfunction. We previously found a sexually dimorphic pattern in how Kyn affects bone, with harmful effects more prevalent in females than males. This raises the possibility that male sex steroids might exert a protective effect that blunts the effects of Kyn in males. To test this, orchiectomy (ORX) or sham surgeries were performed on 6-month-old C57BL/6 mice, after which mice received Kyn (10 mg/kg) or vehicle via intraperitoneal injection, once daily, 5×/week, for four weeks. Bone histomorphometry, DXA, microCT, and serum marker analyses were performed after sacrifice. In vitro studies were performed to specifically test the effect of testosterone on activation of aryl hydrocarbon receptor (AhR)-mediated signaling by Kyn in mesenchymal-lineage cells. Kyn treatment reduced cortical bone mass in ORX- but not sham-operated mice. Trabecular bone was unaffected. Kyn's effects on cortical bone in ORX mice were attributed primarily to enhanced endosteal bone resorption activity. Bone marrow adipose tissue was increased in Kyn-treated ORX animals but was unchanged by Kyn in sham-operated mice. ORX surgery increased mRNA expression of the aryl hydrocarbon receptor (AhR) and its target gene Cyp1a1 in the bone, suggesting a priming and/or amplification of AhR signaling pathways. Mechanistic in vitro studies revealed that testosterone blunted Kyn-stimulated AhR transcriptional activity and Cyp1a1 expression in mesenchymal-linage cells. These data suggest a protective role for male sex steroids in blunting the harmful effects of Kyn in cortical bone. Therefore, testosterone may play an important role in regulating Kyn/AhR signaling in musculoskeletal tissues, suggesting crosstalk between male sex steroids and Kyn signaling may influence age-associated musculoskeletal frailty.
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Affiliation(s)
- Husam Bensreti
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Kanglun Yu
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Dima W Alhamad
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Joseph Shaver
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Helen Kaiser
- Biomedical Sciences, University of South Carolina School of Medicine Greenville, Greenville, SC, United States of America
| | - Roger Zhong
- Department of Neuroscience & Regenerative Medicine, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - William C Whichard
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Emily Parker
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Lindsey Grater
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Hayden Faith
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Maribeth Johnson
- Department of Neuroscience & Regenerative Medicine, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Marion A Cooley
- Department of Oral Biology & Diagnostic Sciences, Dental Collage of Georgia at Augusta University, Augusta, GA, United States of America
| | - Sadanand Fulzele
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - William D Hill
- Department of Pathology, Medical University of South Carolina, Charleston, SC, United States of America
| | - Carlos M Isales
- Department of Neuroscience & Regenerative Medicine, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Mark W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of, Georgia at Augusta University, Augusta, GA, United States of America.
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7
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Liu X, Gu Y, Kumar S, Amin S, Guo Q, Wang J, Fang CL, Cao X, Wan M. Oxylipin-PPARγ-initiated adipocyte senescence propagates secondary senescence in the bone marrow. Cell Metab 2023; 35:667-684.e6. [PMID: 37019080 PMCID: PMC10127143 DOI: 10.1016/j.cmet.2023.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 01/12/2023] [Accepted: 03/06/2023] [Indexed: 04/07/2023]
Abstract
The chronic use of glucocorticoids decreases bone mass and quality and increases bone-marrow adiposity, but the underlying mechanisms remain unclear. Here, we show that bone-marrow adipocyte (BMAd) lineage cells in adult mice undergo rapid cellular senescence upon glucocorticoid treatment. The senescent BMAds acquire a senescence-associated secretory phenotype, which spreads senescence in bone and bone marrow. Mechanistically, glucocorticoids increase the synthesis of oxylipins, such as 15d-PGJ2, for peroxisome proliferator-activated receptor gamma (PPARγ) activation. PPARγ stimulates the expression of key senescence genes and also promotes oxylipin synthesis in BMAds, forming a positive feedback loop. Transplanting senescent BMAds into the bone marrow of healthy mice is sufficient to induce the secondary spread of senescent cells and bone-loss phenotypes, whereas transplanting BMAds harboring a p16INK4a deletion did not show such effects. Thus, glucocorticoid treatment induces a lipid metabolic circuit that robustly triggers the senescence of BMAd lineage cells that, in turn, act as the mediators of glucocorticoid-induced bone deterioration.
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Affiliation(s)
- Xiaonan Liu
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yiru Gu
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Surendra Kumar
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sahran Amin
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Qiaoyue Guo
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiekang Wang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ching-Lien Fang
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xu Cao
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Mei Wan
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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8
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Bensreti H, Alhamad DW, Gonzalez AM, Pizarro-Mondesir M, Bollag WB, Isales CM, McGee-Lawrence ME. Update on the Role of Glucocorticoid Signaling in Osteoblasts and Bone Marrow Adipocytes During Aging. Curr Osteoporos Rep 2023; 21:32-44. [PMID: 36564571 PMCID: PMC9936962 DOI: 10.1007/s11914-022-00772-5] [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: 11/15/2022] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW Bone marrow adipose tissue (BMAT) in the skeleton likely plays a variety of physiological and pathophysiological roles that are not yet fully understood. In elucidating the complex relationship between bone and BMAT, glucocorticoids (GCs) are positioned to play a key role, as they have been implicated in the differentiation of bone marrow mesenchymal stem cells (BMSCs) between osteogenic and adipogenic lineages. The purpose of this review is to illuminate aspects of both endogenous and exogenous GC signaling, including the influence of GC receptors, in mechanisms of bone aging including relationships to BMAT. RECENT FINDINGS Harmful effects of GCs on bone mass involve several cellular pathways and events that can include BMSC differentiation bias toward adipogenesis and the influence of mature BMAT on bone remodeling through crosstalk. Interestingly, BMAT involvement remains poorly explored in GC-induced osteoporosis and warrants further investigation. This review provides an update on the current understanding of the role of glucocorticoids in the biology of osteoblasts and bone marrow adipocytes (BMAds).
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Affiliation(s)
- Husam Bensreti
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Dima W Alhamad
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Alejandro Marrero Gonzalez
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Manuel Pizarro-Mondesir
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wendy B Bollag
- Department of Physiology, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Carlos M Isales
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Orthopaedic Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA.
- Department of Orthopaedic Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA.
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9
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Pachón-Peña G, Bredella MA. Bone marrow adipose tissue in metabolic health. Trends Endocrinol Metab 2022; 33:401-408. [PMID: 35396163 PMCID: PMC9098665 DOI: 10.1016/j.tem.2022.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/25/2022] [Accepted: 03/10/2022] [Indexed: 10/18/2022]
Abstract
Recent studies have highlighted the role of bone marrow adipose tissue (BMAT) as a regulator of skeletal homeostasis and energy metabolism. While long considered an inert filler, occupying empty spaces from bone loss and reduced hematopoiesis, BMAT is now considered a secretory and metabolic organ that responds to nutritional challenges and secretes cytokines, which indirectly impact energy and bone metabolism. The recent advances in our understanding of the function of BMAT have been enabled by novel noninvasive imaging techniques, which allow longitudinal assessment of BMAT in vivo following interventions. This review will focus on the latest advances in our understanding of BMAT and its role in metabolic health. Imaging techniques to quantify the content and composition of BMAT will be discussed.
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Affiliation(s)
| | - Miriam A Bredella
- Division of Musculoskeletal Imaging and Intervention, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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10
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Pierce JL, Sharma AK, Roberts RL, Yu K, Irsik DL, Choudhary V, Dorn JS, Bensreti H, Benson RD, Kaiser H, Khayrullin A, Davis C, Wehrle CJ, Johnson MH, Bollag WB, Hamrick MW, Shi X, Isales CM, McGee-Lawrence ME. The Glucocorticoid Receptor in Osterix-Expressing Cells Regulates Bone Mass, Bone Marrow Adipose Tissue, and Systemic Metabolism in Female Mice During Aging. J Bone Miner Res 2022; 37:285-302. [PMID: 34747055 PMCID: PMC9976194 DOI: 10.1002/jbmr.4468] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 09/23/2021] [Accepted: 10/17/2021] [Indexed: 12/18/2022]
Abstract
Hallmarks of aging-associated osteoporosis include bone loss, bone marrow adipose tissue (BMAT) expansion, and impaired osteoblast function. Endogenous glucocorticoid levels increase with age, and elevated glucocorticoid signaling, associated with chronic stress and dysregulated metabolism, can have a deleterious effect on bone mass. Canonical glucocorticoid signaling through the glucocorticoid receptor (GR) was recently investigated as a mediator of osteoporosis during the stress of chronic caloric restriction. To address the role of the GR in an aging-associated osteoporotic phenotype, the current study utilized female GR conditional knockout (GR-CKO; GRfl/fl :Osx-Cre+) mice and control littermates on the C57BL/6 background aged to 21 months and studied in comparison to young (3- and 6-month-old) mice. GR deficiency in Osx-expressing cells led to low bone mass and BMAT accumulation that persisted with aging. Surprisingly, however, GR-CKO mice also exhibited alterations in muscle mass (reduced % lean mass and soleus fiber size), accompanied by reduced voluntary physical activity, and also exhibited higher whole-body metabolic rate and elevated blood pressure. Moreover, increased lipid storage was observed in GR-CKO osteoblastic cultures in a glucocorticoid-dependent fashion despite genetic deletion of the GR, and could be reversed via pharmacological inhibition of the mineralocorticoid receptor (MR). These findings provide evidence of a role for the GR (and possibly the MR) in facilitating healthy bone maintenance with aging in females. The effects of GR-deficient bone on whole-body physiology also demonstrate the importance of bone as an endocrine organ and suggest evidence for compensatory mechanisms that facilitate glucocorticoid signaling in the absence of osteoblastic GR function; these represent new avenues of research that may improve understanding of glucocorticoid signaling in bone toward the development of novel osteogenic agents. © 2021 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Jessica L Pierce
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Anuj K Sharma
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Rachel L Roberts
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Kanglun Yu
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Debra L Irsik
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, USA.,Charlie Norwood VA Medical Center, Augusta, GA, USA
| | - Vivek Choudhary
- Department of Physiology, Augusta University, Augusta, GA, USA
| | - Jennifer S Dorn
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Husam Bensreti
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Reginald D Benson
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Helen Kaiser
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Andrew Khayrullin
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Colleen Davis
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Chase J Wehrle
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Maribeth H Johnson
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, USA
| | - Wendy B Bollag
- Charlie Norwood VA Medical Center, Augusta, GA, USA.,Department of Physiology, Augusta University, Augusta, GA, USA
| | - Mark W Hamrick
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA
| | - Xingming Shi
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, USA
| | - Carlos M Isales
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, USA
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, GA, USA.,Department of Orthopaedic Surgery, Augusta University, Augusta, GA, USA
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11
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Scheller EL, McGee-Lawrence ME, Lecka-Czernik B. Report From the 6 th International Meeting on Bone Marrow Adiposity (BMA2020). Front Endocrinol (Lausanne) 2021; 12:712088. [PMID: 34335478 PMCID: PMC8323480 DOI: 10.3389/fendo.2021.712088] [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: 05/19/2021] [Accepted: 06/21/2021] [Indexed: 12/25/2022] Open
Abstract
The 6th International Meeting on Bone Marrow Adiposity (BMA) entitled "Marrow Adiposity: Bone, Aging, and Beyond" (BMA2020) was held virtually on September 9th and 10th, 2020. The mission of this meeting was to facilitate communication and collaboration among scientists from around the world who are interested in different aspects of bone marrow adiposity in health and disease. The BMA2020 meeting brought together 198 attendees from diverse research and clinical backgrounds spanning fields including bone biology, endocrinology, stem cell biology, metabolism, oncology, aging, and hematopoiesis. The congress featured an invited keynote address by Ormond MacDougald and ten invited speakers, in addition to 20 short talks, 35 posters, and several training and networking sessions. This report summarizes and highlights the scientific content of the meeting and the progress of the working groups of the BMA society (http://bma-society.org/).
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Affiliation(s)
- Erica L. Scheller
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University, Saint Louis, MO, United States
| | - Meghan E. McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Beata Lecka-Czernik
- Departments of Orthopaedic Surgery, Physiology and Pharmacology, Center for Diabetes and Endocrine Research, University of Toledo, Toledo, OH, United States
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12
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Lee S, Krüger BT, Ignatius A, Tuckermann J. Distinct Glucocorticoid Receptor Actions in Bone Homeostasis and Bone Diseases. Front Endocrinol (Lausanne) 2021; 12:815386. [PMID: 35082759 PMCID: PMC8784516 DOI: 10.3389/fendo.2021.815386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/16/2021] [Indexed: 12/29/2022] Open
Abstract
Glucocorticoids (GCs) are steroid hormones that respond to stress and the circadian rhythm. Pharmacological GCs are widely used to treat autoimmune and chronic inflammatory diseases despite their adverse effects on bone after long-term therapy. GCs regulate bone homeostasis in a cell-type specific manner, affecting osteoblasts, osteoclasts, and osteocytes. Endogenous physiological and exogenous/excessive GCs act via nuclear receptors, mainly via the GC receptor (GR). Endogenous GCs have anabolic effects on bone mass regulation, while excessive or exogenous GCs can cause detrimental effects on bone. GC-induced osteoporosis (GIO) is a common adverse effect after GC therapy, which increases the risk of fractures. Exogenous GC treatment impairs osteoblastogenesis, survival of the osteoblasts/osteocytes and prolongs the longevity of osteoclasts. Under normal physiological conditions, endogenous GCs are regulated by the circadian rhythm and circadian genes display oscillatory rhythmicity in bone cells. However, exogenous GCs treatment disturbs the circadian rhythm. Recent evidence suggests that the disturbed circadian rhythm by continuous exogenous GCs treatment can in itself hamper bone integrity. GC signaling is also important for fracture healing and rheumatoid arthritis, where crosstalk among several cell types including macrophages and stromal cells is indispensable. This review summarizes the complexity of GC actions via GR in bone cells at cellular and molecular levels, including the effect on circadian rhythmicity, and outlines new therapeutic possibilities for the treatment of their adverse effects.
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Affiliation(s)
- Sooyeon Lee
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Benjamin Thilo Krüger
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm, Ulm University Medical Center, Ulm, Germany
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm, Ulm University Medical Center, Ulm, Germany
| | - Jan Tuckermann
- Institute for Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
- *Correspondence: Jan Tuckermann,
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13
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Skeletal glucocorticoid signalling determines leptin resistance and obesity in aging mice. Mol Metab 2020; 42:101098. [PMID: 33045434 PMCID: PMC7596342 DOI: 10.1016/j.molmet.2020.101098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/28/2020] [Accepted: 10/06/2020] [Indexed: 11/23/2022] Open
Abstract
Objective Aging and chronic glucocorticoid excess share a number of critical features, including the development of central obesity, insulin resistance and osteoporosis. Previous studies have shown that skeletal glucocorticoid signalling increases with aging and that osteoblasts mediate the detrimental skeletal and metabolic effects of chronic glucocorticoid excess. Here, we investigated whether endogenous glucocorticoid action in the skeleton contributes to metabolic dysfunction during normal aging. Methods Mice lacking glucocorticoid signalling in osteoblasts and osteocytes (HSD2OB/OCY-tg mice) and their wild-type littermates were studied until 3, 6, 12 and 18 months of age. Body composition, adipose tissue morphology, skeletal gene expression and glucose/insulin tolerance were assessed at each timepoint. Leptin sensitivity was assessed by arcuate nucleus STAT3 phosphorylation and inhibition of feeding following leptin administration. Tissue-specific glucose uptake and adipose tissue oxygen consumption rate were also measured. Results As they aged, wild-type mice became obese and insulin-resistant. In contrast, HSD2OB/OCY-tg mice remained lean and insulin-sensitive during aging. Obesity in wild-type mice was due to leptin resistance, evidenced by an impaired ability of exogenous leptin to suppress food intake and phosphorylate hypothalamic STAT3, from 6 months of age onwards. In contrast, HSD2OB/OCY-tg mice remained leptin-sensitive throughout the study. Compared to HSD2OB/OCY-tg mice, leptin-resistant wild-type mice displayed attenuated sympathetic outflow, with reduced tyrosine hydroxylase expression in both the hypothalamus and thermogenic adipose tissues. Adipose tissue oxygen consumption rate declined progressively in aging wild-type mice but was maintained in HSD2OB/OCY-tg mice. At 18 months of age, adipose tissue glucose uptake was increased 3.7-fold in HSD2OB/OCY-tg mice, compared to wild-type mice. Conclusions Skeletal glucocorticoid signalling is critical for the development of leptin resistance, obesity and insulin resistance during aging. These findings underscore the skeleton's importance in the regulation of body weight and implicate osteoblastic/osteocytic glucocorticoid signalling in the aetiology of aging-related obesity and metabolic disease. As they aged, wild-type CD1 mice became hyperphagic, obese and insulin-resistant. Mice lacking skeletal glucocorticoid signalling (HSD2OB/OCY-tg) were lean and healthy. Unlike wild-type mice, HSD2OB/OCY-tg mice remained leptin-sensitive during aging. Adipose tissue sympathetic outflow was maintained in aging HSD2OB/OCY-tg mice.
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14
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Ding K, McGee-Lawrence ME, Kaiser H, Sharma AK, Pierce JL, Irsik DL, Bollag WB, Xu J, Zhong Q, Hill W, Shi XM, Fulzele S, Kennedy EJ, Elsalanty M, Hamrick MW, Isales CM. Picolinic acid, a tryptophan oxidation product, does not impact bone mineral density but increases marrow adiposity. Exp Gerontol 2020; 133:110885. [PMID: 32088397 PMCID: PMC7065047 DOI: 10.1016/j.exger.2020.110885] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/21/2022]
Abstract
Tryptophan is an essential amino acid catabolized initially to kynurenine (kyn), an immunomodulatory metabolite that we have previously shown to promote bone loss. Kyn levels increase with aging and have also been associated with neurodegenerative disorders. Picolinic acid (PA) is another tryptophan metabolite downstream of kyn. However, in contrast to kyn, PA is reported to be neuroprotective and further, to promote osteogenesis in vitro. Thus, we hypothesized that PA might be osteoprotective in vivo. In an IACUC-approved protocol, we fed PA to aged (23-month-old) C57BL/6 mice for eight weeks. In an effort to determine potential interactions of PA with dietary protein we also fed PA in a low-protein diet (8%). The mice were divided into four groups: Control (18% dietary protein), +PA (700 ppm); Low-protein (8%), +PA (700 ppm). The PA feedings had no impact on mouse weight, body composition or bone density. At sacrifice bone and stem cells were collected for analysis, including μCT and RT-qPCR. Addition of PA to the diet had no impact on trabecular bone parameters. However, marrow adiposity was significantly increased in PA-fed mice, and in bone marrow stromal cells isolated from these mice increases in the expression of the lipid storage genes, Plin1 and Cidec, were observed. Thus, as a downstream metabolite of kyn, PA no longer showed kyn's detrimental effects on bone but instead appears to impact energy balance.
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Affiliation(s)
- Kehong Ding
- Center for Healthy Aging, Augusta University, United States of America; Department of Neuroscience and Regenerative Medicine, Augusta University, United States of America
| | - Meghan E McGee-Lawrence
- Center for Healthy Aging, Augusta University, United States of America; Department of Orthopaedic Surgery, Augusta University, United States of America; Department of Cellular Biology and Anatomy, Augusta University, United States of America
| | - Helen Kaiser
- Department of Cellular Biology and Anatomy, Augusta University, United States of America
| | - Anuj K Sharma
- Department of Cellular Biology and Anatomy, Augusta University, United States of America
| | - Jessica L Pierce
- Department of Cellular Biology and Anatomy, Augusta University, United States of America
| | - Debra L Irsik
- Department of Neuroscience and Regenerative Medicine, Augusta University, United States of America
| | - Wendy B Bollag
- Center for Healthy Aging, Augusta University, United States of America; Department of Medicine, Augusta University, United States of America; Department of Physiology, Augusta University, United States of America; Charlie Norwood VA Medical Center, Augusta, GA 30912, United States of America
| | - Jianrui Xu
- Department of Neuroscience and Regenerative Medicine, Augusta University, United States of America
| | - Qing Zhong
- Center for Healthy Aging, Augusta University, United States of America; Department of Neuroscience and Regenerative Medicine, Augusta University, United States of America
| | - William Hill
- Center for Healthy Aging, Augusta University, United States of America; Department of Pathology and Laboratory Medicine, Medical University of South Carolina, United States of America; Ralph H Johnson Veterans Affairs Medical Center, Charleston, SC 29403, United States of America
| | - Xing-Ming Shi
- Center for Healthy Aging, Augusta University, United States of America; Department of Neuroscience and Regenerative Medicine, Augusta University, United States of America; Department of Orthopaedic Surgery, Augusta University, United States of America
| | - Sadanand Fulzele
- Center for Healthy Aging, Augusta University, United States of America; Department of Orthopaedic Surgery, Augusta University, United States of America
| | - Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA 30602, United States of America
| | - Mohammed Elsalanty
- Center for Healthy Aging, Augusta University, United States of America; Department of Oral Biology, Augusta University, United States of America
| | - Mark W Hamrick
- Center for Healthy Aging, Augusta University, United States of America; Department of Orthopaedic Surgery, Augusta University, United States of America; Department of Cellular Biology and Anatomy, Augusta University, United States of America
| | - Carlos M Isales
- Center for Healthy Aging, Augusta University, United States of America; Department of Medicine, Augusta University, United States of America; Department of Neuroscience and Regenerative Medicine, Augusta University, United States of America; Department of Orthopaedic Surgery, Augusta University, United States of America; Department of Cellular Biology and Anatomy, Augusta University, United States of America.
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15
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Sharma AK, Shi X, Isales CM, McGee-Lawrence ME. Endogenous Glucocorticoid Signaling in the Regulation of Bone and Marrow Adiposity: Lessons from Metabolism and Cross Talk in Other Tissues. Curr Osteoporos Rep 2019; 17:438-445. [PMID: 31749087 DOI: 10.1007/s11914-019-00554-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
PURPOSE OF REVIEW The development of adiposity in the bone marrow, known as marrow adipose tissue (MAT), is often associated with musculoskeletal frailty. Glucocorticoids, which are a key component of the biological response to stress, affect both bone and MAT. These molecules signal through receptors such as the glucocorticoid receptor (GR), but the role of the GR in regulation of MAT is not yet clear from previous studies. The purpose of this review is to establish and determine the role of GR-mediated signaling in marrow adiposity by comparing and contrasting what is known against other energy-storing tissues like adipose tissue, liver, and muscle, to provide better insight into the regulation of MAT during times of metabolic stress (e.g., dietary challenges, aging). RECENT FINDINGS GR-mediated glucocorticoid signaling is critical for proper storage and utilization of lipids in cells such as adipocytes and hepatocytes and proteolysis in muscle, impacting whole-body composition, energy utilization, and homeostasis through a complex network of tissue cross talk between these systems. Loss of GR signaling in bone promotes increased MAT and decreased bone mass. GR-mediated signaling in the liver, adipose tissue, and muscle is critical for whole-body energy and metabolic homeostasis, and both similarities and differences in GR-mediated GC signaling in MAT as compared with these tissues are readily apparent. It is clear that GC-induced pathways work together through these tissues to affect systemic biology, and understanding the role of bone in these patterns of tissue cross talk may lead to a better understanding of MAT-bone biology that improves treatment strategies for frailty-associated diseases.
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Affiliation(s)
- Anuj K Sharma
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1460 Laney Walker Blvd., CB1101, Augusta, GA, USA
| | - Xingming Shi
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, USA
| | - Carlos M Isales
- Department of Neuroscience and Regenerative Medicine, Augusta University, Augusta, GA, USA
- Department of Orthopaedic Surgery, Augusta University, Augusta, GA, USA
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Augusta University, Augusta, GA, USA
| | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, 1460 Laney Walker Blvd., CB1101, Augusta, GA, USA.
- Department of Orthopaedic Surgery, Augusta University, Augusta, GA, USA.
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