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Librizzi M, Naselli F, Abruscato G, Luparello C, Caradonna F. Parathyroid Hormone Related Protein (PTHrP)-Associated Molecular Signatures in Tissue Differentiation and Non-Tumoral Diseases. BIOLOGY 2023; 12:950. [PMID: 37508381 PMCID: PMC10376784 DOI: 10.3390/biology12070950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/14/2023] [Accepted: 07/01/2023] [Indexed: 07/30/2023]
Abstract
Parathyroid-hormone-related protein (PTHrP) is encoded by the PTHLH gene which, via alternative promoter usage and splicing mechanisms, can give rise to at least three isoforms of 139, 141, and 173 amino acids with distinct C-terminals. PTHrP is subjected to different post-translational processing that generates smaller bioactive forms, comprising amino terminus, mid-region (containing a nuclear/nucleolar targeting signal), and carboxy terminus peptides. Both the full-length protein and the discrete peptides are key controllers of viability, proliferation, differentiation, and apoptosis in diverse normal and pathological biological systems via the reprogramming of gene expression and remodulation of PKA or PKC-mediated signalization mechanisms. The aim of this review is to pick up selected studies on PTHrP-associated signatures as revealed by molecular profiling assays, focusing on the available data about exemplary differentiating, differentiated, or nontumoral cell and tissue models. In particular, the data presented relate to adipose, bone, dental, cartilaginous, and skin tissues, as well as intestinal, renal, hepatic, pulmonary, and pancreatic epithelia, with a focus on hepatic fibrosis-, pancreatitis-, and diabetes-related changes as diseased states. When reported, the biochemical and/or physiological aspects associated with the specific molecular modulation of gene expression and signal transduction pathways in the target model systems under examination are also briefly described.
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Affiliation(s)
- Mariangela Librizzi
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università di Palermo, 90128 Palermo, Italy
| | - Flores Naselli
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università di Palermo, 90128 Palermo, Italy
| | - Giulia Abruscato
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università di Palermo, 90128 Palermo, Italy
| | - Claudio Luparello
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università di Palermo, 90128 Palermo, Italy
| | - Fabio Caradonna
- Dipartimento di Scienze e Tecnologie Biologiche Chimiche e Farmaceutiche (STEBICEF), Università di Palermo, 90128 Palermo, Italy
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Ni Q, Chen H, Li B, He H, Shi H, Zhu J, Wang H, Chen L. miR-200b-3p/ERG/PTHrP axis mediates the inhibitory effect of ethanol on the differentiation of fetal cartilage into articular cartilage. Chem Biol Interact 2022; 368:110201. [PMID: 36174738 DOI: 10.1016/j.cbi.2022.110201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/09/2022] [Accepted: 09/21/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE This study aims to further explore cartilage development in prenatal ethanol exposure (PEE) offspring at different times to explore the specific time points and mechanism of ethanol-induced fetal cartilage dysplasia. METHODS On gestational day (GD)14, GD17, and GD20, PEE fetal cartilage was evaluated by morphological analysis. RT-qPCR, immunohistochemistry, and immunofluorescence were used to detect the expression of cartilage marker genes and their regulatory factors. Bone marrow mesenchymal stem cells (BMSCs) were used to explore the effect of ethanol on the differentiation of chondrocytes. Additionally, we used inhibitors, overexpression plasmids and a luciferase reporter assay on GD17 chondrocytes to verify the mechanism. RESULTS PEE significantly reduced cartilage matrix content and the expression of marker genes on GD17 and GD20 but had no effect on GD14. The inhibition of chondrogenic differentiation by PEE mainly occurred on GD14-17. Furthermore, the expression of miR-200b-3p was increased, while that of ERG and PTHrP was markedly reduced in PEE fetal cartilage. In vitro, ethanol (30-120 mM) inhibited the differentiation of BMSCs into chondrocytes in a concentration-dependent manner, accompanied by strong expression of miR-200b-3p and low expression of ERG and PTHrP. Moreover, PTHLH and ERG overexpressed, as well as a miR-200b-3p inhibitor reversed the inhibitory effect of ethanol on the differentiation of fetal chondrocytes. Furthermore, miR-200b-3p could target and negatively regulate ERG. CONCLUSIONS PEE can significantly inhibit the development of articular cartilage, especially during articular cartilage formation. The mechanism is related to the decreased differentiation of fetal cartilage into articular cartilage mediated by the miR-200b-3p/ERG/PTHrP axis.
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Affiliation(s)
- Qubo Ni
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Haitao Chen
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Bin Li
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Hangyuan He
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Huasong Shi
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Jiayong Zhu
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Hui Wang
- Department of Pharmacology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, China; Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan, 430071, China.
| | - Liaobin Chen
- Division of Joint Surgery and Sports Medicine, Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China; Hubei Provincial Key Laboratory of Developmentally Originated Diseases, Wuhan, 430071, China.
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Voga M, Majdic G. Articular Cartilage Regeneration in Veterinary Medicine. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1401:23-55. [DOI: 10.1007/5584_2022_717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Articular Chondrocyte Phenotype Regulation through the Cytoskeleton and the Signaling Processes That Originate from or Converge on the Cytoskeleton: Towards a Novel Understanding of the Intersection between Actin Dynamics and Chondrogenic Function. Int J Mol Sci 2021; 22:ijms22063279. [PMID: 33807043 PMCID: PMC8004672 DOI: 10.3390/ijms22063279] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 02/08/2023] Open
Abstract
Numerous studies have assembled a complex picture, in which extracellular stimuli and intracellular signaling pathways modulate the chondrocyte phenotype. Because many diseases are mechanobiology-related, this review asked to what extent phenotype regulators control chondrocyte function through the cytoskeleton and cytoskeleton-regulating signaling processes. Such information would generate leverage for advanced articular cartilage repair. Serial passaging, pro-inflammatory cytokine signaling (TNF-α, IL-1α, IL-1β, IL-6, and IL-8), growth factors (TGF-α), and osteoarthritis not only induce dedifferentiation but also converge on RhoA/ROCK/Rac1/mDia1/mDia2/Cdc42 to promote actin polymerization/crosslinking for stress fiber (SF) formation. SF formation takes center stage in phenotype control, as both SF formation and SOX9 phosphorylation for COL2 expression are ROCK activity-dependent. Explaining how it is molecularly possible that dedifferentiation induces low COL2 expression but high SF formation, this review theorized that, in chondrocyte SOX9, phosphorylation by ROCK might effectively be sidelined in favor of other SF-promoting ROCK substrates, based on a differential ROCK affinity. In turn, actin depolymerization for redifferentiation would “free-up” ROCK to increase COL2 expression. Moreover, the actin cytoskeleton regulates COL1 expression, modulates COL2/aggrecan fragment generation, and mediates a fibrogenic/catabolic expression profile, highlighting that actin dynamics-regulating processes decisively control the chondrocyte phenotype. This suggests modulating the balance between actin polymerization/depolymerization for therapeutically controlling the chondrocyte phenotype.
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Edwards CM, Johnson RW. From Good to Bad: The Opposing Effects of PTHrP on Tumor Growth, Dormancy, and Metastasis Throughout Cancer Progression. Front Oncol 2021; 11:644303. [PMID: 33828987 PMCID: PMC8019909 DOI: 10.3389/fonc.2021.644303] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Parathyroid hormone related protein (PTHrP) is a multifaceted protein with several biologically active domains that regulate its many roles in normal physiology and human disease. PTHrP causes humoral hypercalcemia of malignancy (HHM) through its endocrine actions and tumor-induced bone destruction through its paracrine actions. PTHrP has more recently been investigated as a regulator of tumor dormancy owing to its roles in regulating tumor cell proliferation, apoptosis, and survival through autocrine/paracrine and intracrine signaling. Tumor expression of PTHrP in late stages of cancer progression has been shown to promote distant metastasis formation, especially in bone by promoting tumor-induced osteolysis and exit from dormancy. In contrast, PTHrP may protect against further tumor progression and improve patient survival in early disease stages. This review highlights current knowledge from preclinical and clinical studies examining the role of PTHrP in promoting tumor progression as well as skeletal and soft tissue metastasis, especially with regards to the protein as a regulator of tumor dormancy. The discussion will also provide perspectives on PTHrP as a prognostic factor and therapeutic target to inhibit tumor progression, prevent tumor recurrence, and improve patient survival.
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Affiliation(s)
- Courtney M Edwards
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Center for Bone Biology, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
| | - Rachelle W Johnson
- Program in Cancer Biology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Center for Bone Biology, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States.,Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, United States
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Todd VM, Johnson RW. Hypoxia in bone metastasis and osteolysis. Cancer Lett 2020; 489:144-154. [PMID: 32561416 PMCID: PMC7429356 DOI: 10.1016/j.canlet.2020.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 05/15/2020] [Accepted: 06/01/2020] [Indexed: 12/19/2022]
Abstract
Hypoxia is a common feature in tumors, driving pathways that promote epithelial-to-mesenchymal transition, invasion, and metastasis. Clinically, high levels of hypoxia-inducible factor (HIF) expression and stabilization at the primary site in many cancer types is associated with poor patient outcomes. Experimental evidence suggests that HIF signaling in the primary tumor promotes their dissemination to the bone, as well as the release of factors such as LOX that act distantly on the bone to stimulate osteolysis and form a pre-metastatic niche. Additionally, the bone itself is a generally hypoxic organ, fueling the activation of HIF signaling in bone resident cells, promoting tumor cell homing to the bone as well as osteoclastogenesis. The hypoxic microenvironment of the bone also stimulates the vicious cycle of tumor-induced bone destruction, further fueling tumor cell growth and osteolysis. Furthermore, hypoxia appears to regulate key tumor dormancy factors. Thus, hypoxia acts both on the tumor cells as well as the metastatic site to promote tumor cell metastasis.
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Affiliation(s)
- Vera M Todd
- Graduate Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA; Vanderbilt Center for Bone Biology, Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Rachelle W Johnson
- Graduate Program in Cancer Biology, Vanderbilt University, Nashville, TN, USA; Vanderbilt Center for Bone Biology, Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.
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Duan ZX, Li YS, Tu C, Xie P, Li YH, Qi L, Li ZH. Identification of a potential gene target for osteoarthritis based on bioinformatics analyses. J Orthop Surg Res 2020; 15:228. [PMID: 32571421 PMCID: PMC7310002 DOI: 10.1186/s13018-020-01756-w] [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: 01/06/2020] [Accepted: 06/16/2020] [Indexed: 12/27/2022] Open
Abstract
Background Osteoarthritis (OA) is the most common chronic joint disease worldwide. It is characterized by pain and limited mobility in the affected joints and may even cause disability. Effective clinical options for its prevention and treatment are still unavailable. This study aimed to identify differences in gene signatures between tissue samples from OA and normal knee joints and to explore potential gene targets for OA. Methods Five gene datasets, namely GSE55457, GSE55235, GSE12021, GSE10575, and GSE1919, were selected from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified using the R programming software. The functions of these DEGs were analyzed, and a protein–protein interaction (PPI) network was constructed. Subsequently, the most relevant biomarker genes were screened using a receiver operating characteristic (ROC) curve analysis. Finally, the expression of the protein encoded by the core gene PTHLH was evaluated in clinical samples. Results Eleven upregulated and 9 downregulated DEGs were shared between the five gene expression datasets. Based on the PPI network and the ROC curves of upregulated genes, PTHLH was identified as the most relevant gene for OA and was selected for further validation. Immunohistochemistry confirmed significantly higher PTHLH expression in OA tissues than in normal tissues. Moreover, similar PTHLH levels were detected in the plasma and knee synovial fluid of OA patients. Conclusion The bioinformatics analysis and preliminary experimental verification performed in this study identified PTHLH as a potential target for the treatment of OA.
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Affiliation(s)
- Zhi-Xi Duan
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Yu-Sheng Li
- Department of Orthopedics, Xiangya Hospital, Central South University, No.87 Xiangya Road, Changsha, 410008, China
| | - Chao Tu
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Peng Xie
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Yi-Han Li
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Lin Qi
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China
| | - Zhi-Hong Li
- Department of Orthopedics, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha, 410011, Hunan, China.
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Browe DC, Coleman CM, Barry FP, Elliman SJ. Hypoxia Activates the PTHrP -MEF2C Pathway to Attenuate Hypertrophy in Mesenchymal Stem Cell Derived Cartilage. Sci Rep 2019; 9:13274. [PMID: 31527619 PMCID: PMC6746812 DOI: 10.1038/s41598-019-49499-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 08/20/2019] [Indexed: 01/22/2023] Open
Abstract
Articular cartilage lacks an intrinsic repair capacity and due to the ability of mesenchymal stem cells (MSCs) to differentiate into chondrocytes, MSCs have been touted as a cellular source to regenerate damaged cartilage. However, a number of prevailing concerns for such a treatment remain. Generally, administration of MSCs into a cartilage defect results in poor regeneration of the damaged cartilage with the repaired cartilage consisting primarily of fibro-cartilage rather than hyaline cartilage. Methods that improve the chondrogenic potential of transplanted MSCs in vivo may be advantageous. In addition, the proclivity of MSC-derived cartilage to undergo hypertrophic differentiation or form bone in vivo also remains a clinical concern. If MSC-derived cartilage was to undergo hypertrophic differentiation in vivo, this would be deleterious in a clinical setting. This study focuses on establishing a mechanism of action by which hypoxia or low oxygen tension can be used to both enhance chondrogenesis and attenuate hypertrophic differentiation of both MSC and ATDC5 derived chondrocytes. Having elucidated a novel mechanism of action, the subsequent goals of this study were to develop an in vitro culture regime to mimic the beneficial effects of physiological low oxygen tension in a normoxic environment.
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Affiliation(s)
- David C Browe
- Regenerative Medicine Institute, National University of Ireland Galway, University Road, Galway, Ireland
| | - Cynthia M Coleman
- Regenerative Medicine Institute, National University of Ireland Galway, University Road, Galway, Ireland
| | - Frank P Barry
- Regenerative Medicine Institute, National University of Ireland Galway, University Road, Galway, Ireland.
| | - Stephen J Elliman
- Orbsen Therapeutics Ltd, National University of Ireland Galway, Distillery Road, Galway, Ireland
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Fahy N, Gardner OFW, Alini M, Stoddart MJ. Parathyroid Hormone-Related Protein Gradients Affect the Progression of Mesenchymal Stem Cell Chondrogenesis and Hypertrophy. Tissue Eng Part A 2018; 24:849-859. [PMID: 29073831 DOI: 10.1089/ten.tea.2017.0337] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION Mesenchymal stem cells (MSCs) are considered a promising cell source for cartilage repair strategies due to their chondrogenic differentiation potential. However, their in vitro tendency to progress toward hypertrophy limits their clinical use. This unfavorable result may be due to the fact that MSCs used in tissue engineering approaches are all at the same developmental stage, and have lost crucial spatial and temporal signaling cues. In this study, we sought to investigate the effect of a spatial parathyroid hormone-related protein (PTHrP) signaling gradient on the chondrogenic differentiation of MSCs and progression to hypertrophy. METHODS Human bone marrow-derived MSCs were transduced with adenoviral vectors overexpressing PTHrP and seeded into fibrin-poly(ester-urethane) scaffolds. To investigate the effect of a spatial PTHrP signaling gradient, scaffolds were seeded with PTHrP-overexpressing MSCs positioned on top of the scaffold, with untransduced MSCs seeded evenly within. Scaffolds were cultured with or without 2 ng/mL transforming growth factor (TGF)-β1 for 28 days. RESULTS PTHrP overexpression increased glycosaminoglycan (GAG) production by MSCs irrespective of TGF-β1 treatment, and exerted differential effects on chondrogenic and hypertrophic gene expression when MSCs were cultured in the presence of a PTHrP signaling gradient. Furthermore, PTHrP-overexpressing MSCs were associated with an increase of endogenous TGF-β1 production and reduced total MMP-13 secretion compared to controls. CONCLUSION The presence of a spatial PTHrP signaling gradient may support chondrogenic differentiation of MSCs and promote the formation of a more stable cartilage phenotype in tissue engineering applications.
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Affiliation(s)
- Niamh Fahy
- 1 AO Research Institute Davos , Davos Platz, Switzerland
| | | | - Mauro Alini
- 1 AO Research Institute Davos , Davos Platz, Switzerland
| | - Martin J Stoddart
- 1 AO Research Institute Davos , Davos Platz, Switzerland .,2 Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent, UK
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Wei Y, Bai L. Recent advances in the understanding of molecular mechanisms of cartilage degeneration, synovitis and subchondral bone changes in osteoarthritis. Connect Tissue Res 2016; 57:245-61. [PMID: 27285430 DOI: 10.1080/03008207.2016.1177036] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Osteoarthritis (OA), the most common form of degenerative joint disease, is linked to high morbidity. It is predicted to be the single greatest cause of disability in the general population by 2030. The development of disease-modifying therapy for OA currently face great obstacle mainly because the onset and development of the disease involve complex molecular mechanisms. In this review, we will comprehensively summarize biological and pathological mechanisms of three key aspects: degeneration of articular cartilage, synovial immunopathogenesis, and changes in subchondral bone. For each tissue, we will focus on the molecular receptors, cytokines, peptidases, related cell, and signal pathways. Agents that specifically block mechanisms involved in synovial inflammation, degeneration of articular cartilage, and subchondral bone remodeling can potentially be exploited to produce targeted therapy for OA. Such new comprehensive agents will benefit affected patients and bring exciting new hope for the treatment of OA.
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Affiliation(s)
- Yingliang Wei
- a Department of Orthopedic Surgery, Sheng-Jing Hospital , China Medical University , ShenYang , China
| | - Lunhao Bai
- a Department of Orthopedic Surgery, Sheng-Jing Hospital , China Medical University , ShenYang , China
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Klingelhöffer C, Reck A, Ettl T, Morsczeck C. The parathyroid hormone-related protein is secreted during the osteogenic differentiation of human dental follicle cells and inhibits the alkaline phosphatase activity and the expression of DLX3. Tissue Cell 2016; 48:334-9. [PMID: 27368119 DOI: 10.1016/j.tice.2016.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/24/2016] [Accepted: 05/28/2016] [Indexed: 10/21/2022]
Abstract
The dental follicle is involved in tooth eruption and it expresses a great amount of the parathyroid hormone-related protein (PTHrP). PTHrP as an extracellular protein is required for a multitude of different regulations of enchondral bone development and differentiation of bone precursor cells and of the development of craniofacial tissues. The dental follicle contains also precursor cells (DFCs) of the periodontium. Isolated DFCs differentiate into periodontal ligament cells, alveolar osteoblast and cementoblasts. However, the role of PTHrP during the human periodontal development remains elusive. Our study evaluated the influence of PTHrP on the osteogenic differentiation of DFCs under in vitro conditions for the first time. The PTHrP protein was highly secreted after 4days of the induction of the osteogenic differentiation of DFCs with dexamethasone (2160.5pg/ml±345.7SD. in osteogenic differentiation medium vs. 315.7pg/ml±156.2SD. in standard cell culture medium; Student's t Test: p<0.05 (n=3)). We showed that the supplementation of the osteogenic differentiation medium with PTHrP inhibited the alkaline phosphatase activity and the expression of the transcription factor DLX3, but the depletion of PTHrP did not support the differentiation of DFCs. Previous studies have shown that Indian Hedgehog (IHH) induces PTHrP and that PTHrP, in turn, inhibits IHH via a negative feedback loop. We showed that SUFU (Suppressor Of Fused Homolog) was not regulated during the osteogenic differentiation in DFCs. So, neither the hedgehog signaling pathway induced PTHrP nor PTHrP suppressed the hedgehog signaling pathway during the osteogenic differentiation in DFCs. In conclusion, our results suggest that PTHrP regulates independently of the hedgehog signaling pathway the osteogenic differentiated in DFCs.
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Affiliation(s)
- C Klingelhöffer
- Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany
| | - A Reck
- Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany
| | - T Ettl
- Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany
| | - C Morsczeck
- Department of Cranio- and Maxillofacial Surgery, Hospital of the University of Regensburg, Regensburg, Germany.
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Abstract
Bone is increasingly viewed as an endocrine organ with key biological functions. The skeleton produces hormones and cytokines, such as FGF23 and osteocalcin, which regulate an extensive list of homoeostatic functions. Some of these functions include glucose metabolism, male fertility, blood cell production and calcium/phosphate metabolism. Many of the genes regulating these functions are specific to bone cells. Some of these genes can be wrongly expressed by other malfunctioning cells, driving the generation of disease. The miRNAs are a class of non-coding RNA molecules that are powerful regulators of gene expression by suppressing and fine-tuning target mRNAs. Expression of one such miRNA, miR-140, is ubiquitous in chondrocyte cells during embryonic bone development. Activity in cells found in the adult breast, colon and lung tissue can silence genes required for tumour suppression. The realization that the same miRNA can be both normal and detrimental, depending on the cell, tissue and time point, provides a captivating twist to the study of whole-organism functional genomics. With the recent interest in miRNAs in bone biology and RNA-based therapeutics on the horizon, we present a review on the role of miR-140 in the molecular events that govern bone formation in the embryo. Cellular pathways involving miR-140 may be reactivated or inhibited when treating skeletal injury or disorder in adulthood. These pathways may also provide a novel model system when studying cancer biology of other cells and tissues.
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Stearic acid induces proinflammatory cytokine production partly through activation of lactate-HIF1α pathway in chondrocytes. Sci Rep 2015; 5:13092. [PMID: 26271607 PMCID: PMC4536527 DOI: 10.1038/srep13092] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/17/2015] [Indexed: 12/22/2022] Open
Abstract
The biomechanics stress and chronic inflammation in obesity are causally linked to osteoarthritis. However, the metabolic factors mediating obesity-related osteoarthritis are still obscure. Here we scanned and identified at least two elevated metabolites (stearic acid and lactate) from the plasma of diet-induced obese mice. We found that stearic acid potentiated LDH-a-dependent production of lactate, which further stabilized HIF1α protein and increased VEGF and proinflammatory cytokine expression in primary mouse chondrocytes. Treatment with LDH-a and HIF1α inhibitors notably attenuated stearic acid-or high fat diet-stimulated proinflammatory cytokine production in vitro and in vivo. Furthermore, positive correlation of plasma lactate, cartilage HIF1α and cytokine levels with the body mass index was observed in subjects with osteoarthritis. In conclusion, saturated free fatty acid induced proinflammatory cytokine production partly through activation of a novel lactate-HIF1α pathway in chondrocytes. Our findings hold promise of developing novel clinical strategies for the management of obesity-related diseases such as osteoarthritis.
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Deng Z, Liu Y, Wang C, Fan H, Ma J, Yu H. Involvement of PI3K/Akt pathway in rat condylar chondrocytes regulated by PTHrP treatment. Arch Oral Biol 2014; 59:1032-41. [DOI: 10.1016/j.archoralbio.2014.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 03/18/2014] [Accepted: 04/19/2014] [Indexed: 11/28/2022]
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