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King JS, Wan M, Wagley Y, Stestiv M, Kalajzic I, Hankenson KD, Sanjay A. Signaling pathways associated with Lgr6 to regulate osteogenesis. Bone 2024:117207. [PMID: 39033993 DOI: 10.1016/j.bone.2024.117207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/13/2024] [Accepted: 07/16/2024] [Indexed: 07/23/2024]
Abstract
Fracture management largely relies on the bone's inherent healing capabilities and, when necessary, surgical intervention. Currently, there are limited osteoinductive therapies to promote healing, making targeting skeletal stem/progenitor cells (SSPCs) a promising avenue for therapeutic development. A limiting factor for this approach is our incomplete understanding of the molecular mechanisms governing SSPCs' behavior. We have recently identified that the Leucine-rich repeat-containing G-protein coupled receptor 6 (Lgr6) is expressed in sub-populations of SSPCs, and is required for maintaining bone volume during adulthood and for proper fracture healing. Lgr family members (Lgr4-6) are markers of stem cell niches and play a role in tissue regeneration primarily by binding R-Spondin (Rspo1-4). This interaction promotes canonical Wnt (cWnt) signaling by stabilizing Frizzled receptors. Interestingly, our findings here indicate that Lgr6 may also influence cWnt-independent pathways. Remarkably, Lgr6 expression was enhanced during Bmp-mediated osteogenesis of both human and murine cells. Using biochemical approaches, RNA sequencing, and bioinformatic analysis of published single-cell data, we found that elements of BMP signaling, including its target gene, pSMAD, and gene ontology pathways, are downregulated in the absence of Lgr6. Our findings uncover a molecular interdependency between the Bmp pathway and Lgr6, offering new insights into osteogenesis and potential targets for enhancing fracture healing.
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Affiliation(s)
- Justin S King
- Department of Orthopaedic Surgery, The Musculoskeletal Research Institute, UCONN Health, Farmington, CT 06032, USA
| | - Matthew Wan
- Department of Orthopaedic Surgery, The Musculoskeletal Research Institute, UCONN Health, Farmington, CT 06032, USA
| | - Yadav Wagley
- Department of Orthopaedic Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Marta Stestiv
- Department of Orthopaedic Surgery, The Musculoskeletal Research Institute, UCONN Health, Farmington, CT 06032, USA
| | - Ivo Kalajzic
- Center for Regenerative Medicine and Skeletal Development, The Musculoskeletal Research Institute, UCONN Health, Farmington, CT 06032, USA
| | - Kurt D Hankenson
- Department of Orthopaedic Surgery, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
| | - Archana Sanjay
- Department of Orthopaedic Surgery, The Musculoskeletal Research Institute, UCONN Health, Farmington, CT 06032, USA.
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Zhu S, Chen W, Masson A, Li YP. Cell signaling and transcriptional regulation of osteoblast lineage commitment, differentiation, bone formation, and homeostasis. Cell Discov 2024; 10:71. [PMID: 38956429 PMCID: PMC11219878 DOI: 10.1038/s41421-024-00689-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 05/04/2024] [Indexed: 07/04/2024] Open
Abstract
The initiation of osteogenesis primarily occurs as mesenchymal stem cells undergo differentiation into osteoblasts. This differentiation process plays a crucial role in bone formation and homeostasis and is regulated by two intricate processes: cell signal transduction and transcriptional gene expression. Various essential cell signaling pathways, including Wnt, BMP, TGF-β, Hedgehog, PTH, FGF, Ephrin, Notch, Hippo, and Piezo1/2, play a critical role in facilitating osteoblast differentiation, bone formation, and bone homeostasis. Key transcriptional factors in this differentiation process include Runx2, Cbfβ, Runx1, Osterix, ATF4, SATB2, and TAZ/YAP. Furthermore, a diverse array of epigenetic factors also plays critical roles in osteoblast differentiation, bone formation, and homeostasis at the transcriptional level. This review provides an overview of the latest developments and current comprehension concerning the pathways of cell signaling, regulation of hormones, and transcriptional regulation of genes involved in the commitment and differentiation of osteoblast lineage, as well as in bone formation and maintenance of homeostasis. The paper also reviews epigenetic regulation of osteoblast differentiation via mechanisms, such as histone and DNA modifications. Additionally, we summarize the latest developments in osteoblast biology spurred by recent advancements in various modern technologies and bioinformatics. By synthesizing these insights into a comprehensive understanding of osteoblast differentiation, this review provides further clarification of the mechanisms underlying osteoblast lineage commitment, differentiation, and bone formation, and highlights potential new therapeutic applications for the treatment of bone diseases.
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Affiliation(s)
- Siyu Zhu
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA
| | - Wei Chen
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA.
| | - Alasdair Masson
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA
| | - Yi-Ping Li
- Division in Cellular and Molecular Medicine, Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, Tulane University, New Orleans, LA, USA.
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Guo X, Lv M, Lin J, Guo J, Lin J, Li S, Sun Y, Zhang X. Latest Progress of LIPUS in Fracture Healing: A Mini-Review. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2024; 43:643-655. [PMID: 38224522 DOI: 10.1002/jum.16403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/09/2023] [Accepted: 12/17/2023] [Indexed: 01/17/2024]
Abstract
The use of low-intensity pulsed ultrasound (LIPUS) for promoting fracture healing has been Food and Drug Administration (FDA)-approved since 1994 due to largely its non-thermal effects of sound flow sound radiation force and so on. Numerous clinical and animal studies have shown that LIPUS can accelerate the healing of fresh fractures, nonunions, and delayed unions in pulse mode regardless of LIPUS devices or circumstantial factors. Rare clinical studies show limitations of LIPUS for treating fractures with intramedullary nail fixation or low patient compliance. The biological effect is achieved by regulating various cellular behaviors involving mesenchymal stem/stromal cells (MSCs), osteoblasts, chondrocytes, and osteoclasts and with dose dependency on LIPUS intensity and time. Specifically, LIPUS promotes the osteogenic differentiation of MSCs through the ROCK-Cot/Tpl2-MEK-ERK signaling. Osteoblasts, in turn, respond to the mechanical signal of LIPUS through integrin, angiotensin type 1 (AT1), and PIEZO1 mechano-receptors, leading to the production of inflammatory factors such as COX-2, MCP-1, and MIP-1β fracture repair. LIPUS also induces CCN2 expression in chondrocytes thereby coordinating bone regeneration. Finally, LIPUS suppresses osteoclast differentiation and gene expression by interfering with the ERK/c-Fos/NFATc1 cascade. This mini-review revisits the known effects and mechanisms of LIPUS on bone fracture healing and strengthens the need for further investigation into the underlying mechanisms.
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Affiliation(s)
- Xin Guo
- School of Rehabilitation Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
| | - Maojiang Lv
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
- Zun Yi Medical University, Zhuhai, China
| | - Jie Lin
- Department of Joint Laboratory for Translational Medicine Research, Liaocheng People's Hospital, Liaocheng, China
| | - Jiang Guo
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
| | - Jianjing Lin
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
| | - Shun Li
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
| | - Yi Sun
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong SAR, China
| | - Xintao Zhang
- School of Rehabilitation Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
- Department of Sports Medicine and Rehabilitation, Peking University Shenzhen Hospital, Shenzhen, China
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Rubitschung K, Sherwood A, Kapadia R, Xi Y, Hajibeigi A, Rubinow KB, Zerwekh JE, Öz OK. Aromatase deficiency in transplanted bone marrow cells improves vertebral trabecular bone quantity, connectivity, and mineralization and decreases cortical porosity in murine bone marrow transplant recipients. PLoS One 2024; 19:e0296390. [PMID: 38315701 PMCID: PMC10843046 DOI: 10.1371/journal.pone.0296390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 12/12/2023] [Indexed: 02/07/2024] Open
Abstract
Estradiol is an important regulator of bone accumulation and maintenance. Circulating estrogens are primarily produced by the gonads. Aromatase, the enzyme responsible for the conversion of androgens to estrogen, is expressed by bone marrow cells (BMCs) of both hematopoietic and nonhematopoietic origin. While the significance of gonad-derived estradiol to bone health has been investigated, there is limited understanding regarding the relative contribution of BMC derived estrogens to bone metabolism. To elucidate the role of BMC derived estrogens in male bone, irradiated wild-type C57BL/6J mice received bone marrow cells transplanted from either WT (WT(WT)) or aromatase-deficient (WT(ArKO)) mice. MicroCT was acquired on lumbar vertebra to assess bone quantity and quality. WT(ArKO) animals had greater trabecular bone volume (BV/TV p = 0.002), with a higher trabecular number (p = 0.008), connectivity density (p = 0.017), and bone mineral content (p = 0.004). In cortical bone, WT(ArKO) animals exhibited smaller cortical pores and lower cortical porosity (p = 0.02). Static histomorphometry revealed fewer osteoclasts per bone surface (Oc.S/BS%), osteoclasts on the erosion surface (ES(Oc+)/BS, p = 0.04) and low number of osteoclasts per bone perimeter (N.Oc/B.Pm, p = 0.01) in WT(ArKO). Osteoblast-associated parameters in WT(ArKO) were lower but not statistically different from WT(WT). Dynamic histomorphometry suggested similar bone formation indices' patterns with lower mean values in mineral apposition rate, label separation, and BFR/BS in WT(ArKO) animals. Ex vivo bone cell differentiation assays demonstrated relative decreased osteoblast differentiation and ability to form mineralized nodules. This study demonstrates a role of local 17β-estradiol production by BMCs for regulating the quantity and quality of bone in male mice. Underlying in vivo cellular and molecular mechanisms require further study.
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Affiliation(s)
- Katie Rubitschung
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Amber Sherwood
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Rasesh Kapadia
- Scanco USA Incorporated, Wayne, Pennsylvania, United States of America
| | - Yin Xi
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Asghar Hajibeigi
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Katya B. Rubinow
- Division of Metabolism, Endocrinology, and Nutrition, University of Washington Medicine Diabetes Institute, Seattle, Washington, United States of America
| | - Joseph E. Zerwekh
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Orhan K. Öz
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, Dallas, Texas, United States of America
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Wu G, Wang D, Xiong F, Liu W, Wang Q, Chen J, Wang B, Chen Y. Upregulation of RSPO3 via targeted promoter DNA demethylation inhibits the progression of cholangiocarcinoma. Clin Epigenetics 2023; 15:177. [PMID: 37932819 PMCID: PMC10629118 DOI: 10.1186/s13148-023-01592-9] [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: 08/07/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023] Open
Abstract
BACKGROUND Cholangiocarcinoma (CCA) refers to a collection of malignant tumors that develop from the biliary epithelium. Extensive clinical evidence and epidemiological observations indicate a concerning increase in both the incidence and mortality rates of CCA. Surgical resection is currently the sole available cure for CCA. However, it is unfortunate that only a fraction of patients has access to surgery at the time of diagnosis. Moreover, there is a high incidence of cancer recurrence after resection, and systemic treatments have limited efficacy. Therefore, the identification of novel biomarkers for CCA-targeted molecular therapy remains a crucial task in oncology research. RESULTS Our study demonstrated that low expression of RSPO3 was associated with poorer survival rates in patients with CCA. We found that the RSPO3 promoter DNA was hypermethylated in CCA, which was correlated with the low expression of RSPO3. The expression of RSPO3 was influenced by the balance between the DNA methyltransferase DNMT3a and the DNA demethylase TET1 in CCA. In vitro and in vivo experiments showed that targeting RSPO3 promoter DNA methylation using dCas9DNMT3a promoted tumorigenicity of CCA, while targeted RSPO3 promoter DNA demethylation using dCas9TET1CD inhibited CCA tumorigenicity. Additionally, in our primary CCA model, knockdown of Rspo3 promoted CCA progression, whereas overexpression of Rspo3 inhibited CCA progression. CONCLUSIONS Our findings suggest that increased methylation and decreased expression of RSPO3 may indicate a poor prognosis in CCA. Restoring RSPO3 expression by targeting promoter DNA demethylation could offer insights for precise treatment of CCA.
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Affiliation(s)
- Guanhua Wu
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China
| | - Da Wang
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China
| | - Fei Xiong
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China
| | - Wenzheng Liu
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China
| | - Qi Wang
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China
| | - Junsheng Chen
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China
| | - Bing Wang
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China.
| | - Yongjun Chen
- Department of Biliary-Pancreatic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Road, Wuhan, 430074, Hubei, China.
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Daamouch S, Thiele S, Hofbauer L, Rauner M. Effects of adipocyte-specific Dkk1 deletion on bone homeostasis and obesity-induced bone loss in male mice. Endocr Connect 2023; 12:e230251. [PMID: 37615386 PMCID: PMC10563648 DOI: 10.1530/ec-23-0251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/24/2023] [Indexed: 08/25/2023]
Abstract
The link between obesity and low bone strength has become a significant medical concern. The canonical Wnt signaling pathway is a key regulator of mesenchymal stem cell differentiation into either osteoblasts or adipocytes with active Wnt signaling promoting osteoblastogenesis. Our previous research indicated that Dickkopf-1 (Dkk1), a Wnt inhibitor, is upregulated in bone tissue in obesity and that osteoblast-derived Dkk1 drives obesity-induced bone loss. However, Dkk1 is also produced by adipocytes, but the impact of adipogenic Dkk1 on bone remodeling and its role in obesity-induced bone loss remain unclear. Thus, in this study, we investigated the influence of adipogenic Dkk1 on bone homeostasis and obesity-induced bone loss in mice. To that end, deletion of Dkk1 in adipocytes was induced by tamoxifen administration into 8-week-old male Dkk1fl/fl;AdipoQcreERT2 mice. Bone and fat mass were analyzed at 12 and 20 weeks of age. Obesity was induced in 8-week-old male Dkk1fl/fl;AdipoQcre mice with a high-fat diet (HFD) rich in saturated fats for 12 weeks. We observed that 12-week-old male mice without adipogenic Dkk1 had a significant increase in trabecular bone volume in the vertebrae and femoral bones. While histological and serological bone formation markers were not different, the number of osteoclasts and adipocytes was decreased in the vertebral bones of Dkk1fl/fl;AdipoQcre-positive mice. Despite the increased bone mass in 12-week-old male mice, at 20 weeks of age, there was no difference in the bone volume between the controls and Dkk1fl/fl;AdipoQcre-positive mice. Also, Dkk1fl/fl;AdipoQcre-positive mice were not protected from HFD-induced bone loss. Even though mRNA expression levels of Sost, another important Wnt inhibitor, in bone from Dkk1-deficient mice fed with HFD were decreased compared to Dkk1-sufficient mice on an HFD, this did not prevent the HFD-induced suppression of bone formation. In conclusion, adipogenic Dkk1 may play a transient role in bone mass regulation during adolescence, but it does not contribute to bone homeostasis or obesity-induced bone loss later in life.
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Affiliation(s)
- Souad Daamouch
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Sylvia Thiele
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Lorenz Hofbauer
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
| | - Martina Rauner
- Department of Medicine III and Center for Healthy Aging, Technische Universität Dresden, Dresden, Germany
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