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Coe LM, Tekalur SA, Shu Y, Baumann MJ, McCabe LR. Bisphosphonate treatment of type I diabetic mice prevents early bone loss but accentuates suppression of bone formation. J Cell Physiol 2015; 230:1944-53. [PMID: 25641511 DOI: 10.1002/jcp.24929] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/08/2015] [Indexed: 12/13/2022]
Abstract
Type I (T1) diabetes is an autoimmune and metabolic disease associated with bone loss. Previous studies demonstrate that T1-diabetes decreases osteoblast activity and viability. Bisphosphonate therapy, commonly used to treat osteoporosis, is demonstrated to inhibit osteoclast activity as well as osteoblast apoptosis. Therefore, we examined the effect of weekly alendronate treatments on T1-diabetes induced osteoblast apoptosis and bone loss. Bone TUNEL assays identified that alendronate therapy prevents the diabetes-induced osteoblast death observed during early stages of diabetes development. Consistent with this, alendronate treatment for 40 days was able to prevent diabetes-induced trabecular bone loss. Alendronate was also able to reduce marrow adiposity in both control diabetic mice compared to untreated mice. Mechanical testing indicated that 40 days of alendronate treatment increased bone stiffness but decreased the work required for fracture in T1-diabetic and alendronate treated mice. Of concern at this later time point, bone formation rate and osteoblast markers, which were already decreased in diabetic mice, were further suppressed in alendronate-treated diabetic mice. Taken together, our results suggest that short-term alendronate treatment can prevent T1-diabetes-induced bone loss in mice, possibly in part by inhibiting diabetes onset associated osteoblast death, while longer treatment enhanced bone density but at the cost of further suppressing bone formation in diabetic mice.
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Affiliation(s)
- Lindsay M Coe
- Department of Physiology, Biomedical Imaging Research Center, Michigan State University, East Lansing, Michigan
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52
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Gonnelli S, Caffarelli C, Giordano N, Nuti R. The prevention of fragility fractures in diabetic patients. Aging Clin Exp Res 2015; 27:115-24. [PMID: 25059454 DOI: 10.1007/s40520-014-0258-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 07/01/2014] [Indexed: 01/10/2023]
Abstract
Patients with diabetes mellitus (DM) are at greater risk of fractures mostly due to not only extraskeletal factors, such as propensity to falls, but also to bone quality alteration, which reduces bone strength. In people with DM, insulin deficit and hyperglycemia seem to play a role in determining bone formation alteration by AGE accumulation which directly influences osteoblast activity. Although there are conflicting data in the literature, adequate glycemic control with hypoglycemic treatment may be an important element in preventing bone tissue alterations in both type 1 and type 2 DM. Diabetes status is a predictive of future hip and major osteoporosis fractures independently of BMD and FRAX probability. Attention should be paid to the use of thiazolidinediones, especially in older women, because the direct negative effect on bone could exceed the positive effect of glycemic control. Systematic screening for complications and fall prevention efforts, along with calcium and vitamin D repletion and adequate physical activity, represents the mainstay of fracture prevention in DM patients. All anticatabolic drugs (raloxifene, bisphosphonates, denosumab) seem to be effective in DM patients. On the basis of pathophysiological evidence that suggests low bone formation in DM patients, osteoanabolic therapies such as teriparatide might represent an important therapeutic option for DM patients with severe osteoporosis and/or multiple fractures. The search for better methods for the identification of fragility fracture risk in the growing population of adult and elderly subjects with DM might be considered a clinical priority which could improve the prevention of fracture in DM patients.
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Affiliation(s)
- Stefano Gonnelli
- Department of Medicine, Surgery and Neuroscience, University of Siena, Policlinico Le Scotte, Viale Bracci 2, 53100, Siena, Italy,
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53
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Abstract
There are several mechanisms by which diabetes could affect bone mass and strength. These mechanisms include insulin deficiency; hyperglycemia; the accumulation of advanced glycation end products that may influence collagen characteristics; marrow adiposity and bone inflammation. Furthermore, associated diabetic complications and treatment with thaizolidinediones may also increase risk of fracturing. The following article provides its readers with an update on the latest information pertaining to diabetes related bone skeletal fragility. In the authors' opinion, future studies are needed in order to clarify the impact of different aspects of diabetes metabolism, glycemic control, and specific treatments for diabetes on bone. Given that dual energy x-ray absorptiometry is a poor predictor of bone morbidity in this group of patients, there is a need to explore novel approaches for assessing bone quality. It is important that we develop a better understanding of how diabetes affects bone in order to improve our ability to protect bone health and prevent fractures in the growing population of adults with diabetes.
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Affiliation(s)
- Naiemh Abdalrahman
- a Developmental Endocrinology Research Group, Royal Hospital for Sick Children, School of Medicine, University of Glasgow, Yorkhill, Glasgow G3 8SJ, UK
| | - Suet Ching Chen
- a Developmental Endocrinology Research Group, Royal Hospital for Sick Children, School of Medicine, University of Glasgow, Yorkhill, Glasgow G3 8SJ, UK
| | - Jessie Ruijun Wang
- a Developmental Endocrinology Research Group, Royal Hospital for Sick Children, School of Medicine, University of Glasgow, Yorkhill, Glasgow G3 8SJ, UK
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54
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Type 1 diabetes and osteoporosis: from molecular pathways to bone phenotype. J Osteoporos 2015; 2015:174186. [PMID: 25874154 PMCID: PMC4385591 DOI: 10.1155/2015/174186] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/09/2015] [Indexed: 01/06/2023] Open
Abstract
The link between type 1 diabetes mellitus (DM1) and osteoporosis, identified decades ago, has gained attention in recent years. While a number of cellular mechanisms have been postulated to mediate this association, it is now established that defects in osteoblast differentiation and activity are the main culprits underlying bone fragility in DM1. Other contributing factors include an accumulation of advanced glycation end products (AGEs) and the development of diabetes complications (such as neuropathy and hypoglycemia), which cause further decline in bone mineral density (BMD), worsening geometric properties within bone, and increased fall risk. As a result, patients with DM1 have a 6.9-fold increased incidence of hip fracture compared to controls. Despite this increased fracture risk, bone fragility remains an underappreciated complication of DM1 and is not addressed in most diabetes guidelines. There is also a lack of data regarding the efficacy of therapeutic strategies to treat osteoporosis in this patient population. Together, our current understanding of bone fragility in DM1 calls for an update of diabetes guidelines, better screening tools, and further research into the use of therapeutic strategies in this patient population.
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Chandra A, Lin T, Zhu J, Tong W, Huo Y, Jia H, Zhang Y, Liu XS, Cengel K, Xia B, Qin L. PTH1-34 blocks radiation-induced osteoblast apoptosis by enhancing DNA repair through canonical Wnt pathway. J Biol Chem 2014; 290:157-67. [PMID: 25336648 DOI: 10.1074/jbc.m114.608158] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Focal radiotherapy for cancer patients has detrimental effects on bones within the radiation field and the primary clinical signs of bone damage include the loss of functional osteoblasts. We reported previously that daily injection of parathyroid hormone (PTH, 1-34) alleviates radiation-induced osteopenia in a preclinical radiotherapy model by improving osteoblast survival. To elucidate the molecular mechanisms, we irradiated osteoblastic UMR 106-01 cells and calvarial organ culture and demonstrated an anti-apoptosis effect of PTH1-34 on these cultures. Inhibitor assay indicated that PTH exerts its radioprotective action mainly through protein kinase A/β-catenin pathway. γ-H2AX foci staining and comet assay revealed that PTH efficiently promotes the repair of DNA double strand breaks (DSBs) in irradiated osteoblasts via activating the β-catenin pathway. Interestingly, Wnt3a alone also blocked cell death and accelerated DNA repair in primary osteoprogenitors, osteoblastic and osteocytic cells after radiation through the canonical signaling. Further investigations revealed that both Wnt3a and PTH increase the amount of Ku70, a core protein for initiating the assembly of DSB repair machinery, in osteoblasts after radiation. Moreover, down-regulation of Ku70 by siRNA abrogated the prosurvival effect of PTH and Wnt3a on irradiated osteoblasts. In summary, our results identify a novel role of PTH and canonical Wnt signaling in regulating DSB repair machinery and apoptosis in osteoblasts and shed light on using PTH1-34 or Wnt agonist as possible therapy for radiation-induced osteoporosis.
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Affiliation(s)
| | - Tiao Lin
- From the Department of Orthopaedic Surgery, the Department of Orthopaedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Ji Zhu
- From the Department of Orthopaedic Surgery
| | - Wei Tong
- From the Department of Orthopaedic Surgery, the Department of Orthopaedic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022 Hubei, China
| | - Yanying Huo
- the Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08903, and
| | - Haoruo Jia
- From the Department of Orthopaedic Surgery
| | - Yejia Zhang
- Departments of Physical Medicine & Rehabilitation and Orthopedic Surgery, and the Translational Musculoskeletal Research Center, Philadelphia Veterans Affairs Medical Center, Philadelphia, Pennsylvania 19104
| | | | - Keith Cengel
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Bing Xia
- the Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey and Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, New Brunswick, New Jersey 08903, and
| | - Ling Qin
- From the Department of Orthopaedic Surgery,
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Chandra A, Lin T, Tribble MB, Zhu J, Altman AR, Tseng WJ, Zhang Y, Akintoye SO, Cengel K, Liu XS, Qin L. PTH1-34 alleviates radiotherapy-induced local bone loss by improving osteoblast and osteocyte survival. Bone 2014; 67:33-40. [PMID: 24998454 PMCID: PMC4154509 DOI: 10.1016/j.bone.2014.06.030] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 06/19/2014] [Accepted: 06/25/2014] [Indexed: 11/20/2022]
Abstract
Cancer radiotherapy is often complicated by a spectrum of changes in the neighboring bone from mild osteopenia to osteoradionecrosis. We previously reported that parathyroid hormone (PTH, 1-34), an anabolic agent for osteoporosis, reversed bone structural deterioration caused by multiple microcomputed tomography (microCT) scans in adolescent rats. To simulate clinical radiotherapy for cancer patients and to search for remedies, we focally irradiated the tibial metaphyseal region of adult rats with a newly available small animal radiation research platform (SARRP) and treated these rats with intermittent injections of PTH1-34. Using a unique 3D image registration method that we recently developed, we traced the local changes of the same trabecular bone before and after treatments, and observed that, while radiation caused a loss of small trabecular elements leading to significant decreases in bone mass and strength, PTH1-34 preserved all trabecular elements in irradiated bone with remarkable increases in bone mass and strength. Histomorphometry demonstrated that SARRP radiation severely reduced osteoblast number and activity, which were impressively reversed by PTH treatment. In contrast, suppressing bone resorption by alendronate failed to rescue radiation-induced bone loss and to block the rescue effect of PTH1-34. Furthermore, histological analyses revealed that PTH1-34 protected osteoblasts and osteocytes from radiation-induced apoptosis and attenuated radiation-induced bone marrow adiposity. Taken together, our data strongly support a robust radioprotective effect of PTH on trabecular bone integrity through preserving bone formation and shed light on further investigations of an anabolic therapy for radiation-induced bone damage.
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Affiliation(s)
- Abhishek Chandra
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tiao Lin
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Orthopaedic Surgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
| | - Mary Beth Tribble
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ji Zhu
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Allison R Altman
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wei-Ju Tseng
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yejia Zhang
- Philadelphia Veterans Affairs Medical Center, Department of Physical Medicine and Rehabilitation, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sunday O Akintoye
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Keith Cengel
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - X Sherry Liu
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ling Qin
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Abstract
Type 1 diabetes (T1D) is autoimmune disease with chronic hyperglycaemic state. Besides diabetic retinopathy, nephropathy, and neuropathy, T1D is characterized by poor bone health. The reduced bone mineralization and quality/strength, due to hyperglycemia, hypoinsulinemia, autoimmune inflammation, low levels of insulin growth factor-1 (IGF-1), and vitamin D, lead to vertebral/hip fractures. Young age of T1D manifestation, chronic poor glycemic control, high daily insulin dose, low BMI, reduced renal function, and the presence of complications can be helpful in identifying T1D patients at risk of reduced bone mineral density. Although risk factors for fracture risk are still unknown, chronic poor glycemic control and presence of diabetic complications might raise the suspicion of elevated fracture risk in T1D. In the presence of the risk factors, the assessment of bone mineral density by dual-energy X-ray absorptiometry and the search of asymptomatic vertebral fracture by lateral X-ray radiography of thorax-lumbar spine should be recommended. The improvement of glycemic control may have a beneficial effect on bone in T1D. Several experiments showed promising results on using anabolic pharmacological agents (recombinant IGF-1 and parathyroid hormone) in diabetic rodents with bone disorder. Randomized clinical trials are needed in order to test the possible use of bone anabolic therapies in humans with T1D.
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58
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Abstract
With better care and intensive insulin therapy, microvascular complications have reduced and longevity has increased in patients with type 1 diabetes (T1DM). Therefore, there is a need to change the focus from microvascular complications to cardiovascular disease and osteoporosis. Though number of studies from other parts of the world show that patients with T1DM are at increased risk of osteoporosis and fractures, there is a paucity of data from India. A number of factors and mechanisms affecting bone health in patients with T1DM have been proposed. The main defect in genesis of osteoporosis is osteoblastic function, rather than osteoclastic overfunction. Assessment of bone mineral density by dual X-ray absorptiometry and other risk factors for osteoporosis, as a part of diagnostic procedure can help to design tailored treatment plans. A physically active healthy lifestyle, prevention of diabetic complications and adequate calcium and vitamin D supplementation are the mainstay for prevention of osteoporosis. Treatment of osteoporosis is not evidence based but it is proposed to be similar to osteoporosis associated with other conditions. Bisphosphonates are the mainstay for treatment of osteoporosis in patients with T1DM. However, more studies are needed to make definitive guidelines on prevention and treatment of osteoporosis in patients with T1DM.
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Affiliation(s)
- Pooja Dhaon
- Department of Rheumatology, King George Medical University, Lucknow, Uttar Pradesh, India
| | - Viral N. Shah
- Barbara Davis Center for Diabetes, University of Colorado, CO, USA
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59
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Weinberg E, Maymon T, Moses O, Weinreb M. Streptozotocin-induced diabetes in rats diminishes the size of the osteoprogenitor pool in bone marrow. Diabetes Res Clin Pract 2014; 103:35-41. [PMID: 24314392 DOI: 10.1016/j.diabres.2013.11.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/24/2013] [Accepted: 11/12/2013] [Indexed: 12/15/2022]
Abstract
AIMS Bone formation is reduced in animals and humans with type 1 diabetes, leading to lower bone mass and inferior osseous healing. Since bone formation greatly depends on the recruitment of osteoblasts from their bone marrow precursors, we tested whether experimental type 1 diabetes in rats diminishes the number of bone marrow osteoprogenitors. METHODS Diabetes was induced by 65 mg/kg streptozotocin and after 4 weeks, femoral bone marrow cells were extracted and cultured. Tibia and femur were frozen for further analysis. RESULTS The size of the osteoprogenitor pool in bone marrow of diabetic rats was significantly reduced, as evidenced by (1) lower (~35 %) fraction of adherent stromal cells (at 24h of culture); (2) lower (20-25%) alkaline phosphatase activity at 10 days of culture; and (3) lower (~40 %) mineralized nodule formation at 21 days of culture. Administration of insulin to hyperglycemic rats normalized glycemia and abrogated most of the decline in ex vivo mineralized nodule formation. Apoptotic cells in tibial bone marrow were more numerous in hyperglycemic rats. Also, the levels of malondialdehyde (indicator of oxidative stress) were significantly elevated in bone marrow of diabetic animals. CONCLUSIONS Experimental type 1 diabetes diminishes the osteoprogenitor population in bone marrow, possibly due to increased apoptosis via Oxidative Stress. Reduced number of osteoprogenitors is likely to impair osteoblastogenesis, bone formation, and bone healing in diabetic animals.
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Affiliation(s)
- E Weinberg
- Department of Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - T Maymon
- Department of Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - O Moses
- Department of Periodontology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - M Weinreb
- Department of Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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60
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Napoli N, Strollo R, Paladini A, Briganti SI, Pozzilli P, Epstein S. The alliance of mesenchymal stem cells, bone, and diabetes. Int J Endocrinol 2014; 2014:690783. [PMID: 25140176 PMCID: PMC4124651 DOI: 10.1155/2014/690783] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 06/11/2014] [Indexed: 12/15/2022] Open
Abstract
Bone fragility has emerged as a new complication of diabetes. Several mechanisms in diabetes may influence bone homeostasis by impairing the action between osteoblasts, osteoclasts, and osteocytes and/or changing the structural properties of the bone tissue. Some of these mechanisms can potentially alter the fate of mesenchymal stem cells, the initial precursor of the osteoblast. In this review, we describe the main factors that impair bone health in diabetic patients and their clinical impact.
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Affiliation(s)
- Nicola Napoli
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
- Division of Bone and Mineral Diseases, Washington University in St Louis, St Louis, MO, USA
- *Nicola Napoli:
| | - Rocky Strollo
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
| | - Angela Paladini
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
| | - Silvia I. Briganti
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
| | - Paolo Pozzilli
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
- Centre for Diabetes, The Blizard Building, Barts and The London School of Medicine, Queen Mary, University of London, London, UK
| | - Sol Epstein
- Division of Endocrinology, Mount Sinai School of Medicine, New York, USA
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61
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Khedgikar V, Kushwaha P, Gautam J, Verma A, Changkija B, Kumar A, Sharma S, Nagar GK, Singh D, Trivedi PK, Sangwan NS, Mishra PR, Trivedi R. Withaferin A: a proteasomal inhibitor promotes healing after injury and exerts anabolic effect on osteoporotic bone. Cell Death Dis 2013; 4:e778. [PMID: 23969857 PMCID: PMC3763455 DOI: 10.1038/cddis.2013.294] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 05/16/2013] [Accepted: 05/29/2013] [Indexed: 11/27/2022]
Abstract
Withania somnifera or Ashwagandha is a medicinal herb of Ayurveda. Though the extract and purified molecules, withanolides, from this plant have been shown to have different pharmacological activities, their effect on bone formation has not been studied. Here, we show that one of the withanolide, withaferin A (WFA) acts as a proteasomal inhibitor (PI) and binds to specific catalytic β subunit of the 20S proteasome. It exerts positive effect on osteoblast by increasing osteoblast proliferation and differentiation. WFA increased expression of osteoblast-specific transcription factor and mineralizing genes, promoted osteoblast survival and suppressed inflammatory cytokines. In osteoclast, WFA treatment decreased osteoclast number directly by decreasing expression of tartarate-resistant acid phosphatase and receptor activator of nuclear factor kappa-B (RANK) and indirectly by decreasing osteoprotegrin/RANK ligand ratio. Our data show that in vitro treatment of WFA to calvarial osteoblast cells decreased expression of E3 ubiquitin ligase, Smad ubiquitin regulatory factor 2 (Smurf2), preventing degradation of Runt-related transcription factor 2 (RunX2) and relevant Smad proteins, which are phosphorylated by bone morphogenetic protein 2. Increased Smurf2 expression due to exogenous treatment of tumor necrosis factor α (TNFα) to primary osteoblast cells was decreased by WFA treatment. This was corroborated by using small interfering RNA against Smurf2. Further, WFA also blocked nuclear factor kappa-B (NF-kB) signaling as assessed by tumor necrosis factor stimulated nuclear translocation of p65-subunit of NF-kB. Overall data show that in vitro proteasome inhibition by WFA simultaneously promoted osteoblastogenesis by stabilizing RunX2 and suppressed osteoclast differentiation, by inhibiting osteoclastogenesis. Oral administration of WFA to osteopenic ovariectomized mice increased osteoprogenitor cells in the bone marrow and increased expression of osteogenic genes. WFA supplementation improved trabecular micro-architecture of the long bones, increased biomechanical strength parameters of the vertebra and femur, decreased bone turnover markers (osteocalcin and TNFα) and expression of skeletal osteoclastogenic genes. It also increased new bone formation and expression of osteogenic genes in the femur bone as compared with vehicle groups (Sham) and ovariectomy (OVx), Bortezomib (known PI), injectible parathyroid hormone and alendronate (FDA approved drugs). WFA promoted the process of cortical bone regeneration at drill-holes site in the femur mid-diaphysis region and cortical gap was bridged with woven bone within 11 days of both estrogen sufficient and deficient (ovariectomized, Ovx) mice. Together our data suggest that WFA stimulates bone formation by abrogating proteasomal machinery and provides knowledge base for its clinical evaluation as a bone anabolic agent.
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Affiliation(s)
- V Khedgikar
- Division of Endocrinology and Center for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226001, India
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62
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López-Herradón A, Portal-Núñez S, García-Martín A, Lozano D, Pérez-Martínez FC, Ceña V, Esbrit P. Inhibition of the canonical Wnt pathway by high glucose can be reversed by parathyroid hormone-related protein in osteoblastic cells. J Cell Biochem 2013; 114:1908-16. [DOI: 10.1002/jcb.24535] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 02/28/2013] [Indexed: 01/17/2023]
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63
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Abstract
Osteoporosis and obesity are chronic disorders that are both increasing in prevalence. The pathophysiology of these conditions is multifactorial and includes genetic, environmental and hormonal determinants. Although it has long been considered that these are distinct disorders rarely found in the same individual, emerging evidence from basic and clinical studies support an important interaction between adipose tissue and the skeleton. It is proposed that adiposity may influence bone remodelling through three mechanisms: (i) secretion of cytokines that directly target bone, (ii) production of adipokines that influence the central nervous system thereby changing sympathetic impulses to bone and (iii) paracrine influences on adjacent skeletal cells. Here we focus on the current understanding of bone-fat interactions and the clinical implications of recent studies linking obesity to osteoporosis.
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Affiliation(s)
- M Kawai
- Department of Bone and Mineral Research, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Osaka, Japan
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