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Liu J, Liu R, Wang H, Zhang Z, Wang J, Wei F. CircPRKD3/miR-6783-3p responds to mechanical force to facilitate the osteogenesis of stretched periodontal ligament stem cells. J Orthop Surg Res 2024; 19:257. [PMID: 38649946 PMCID: PMC11036753 DOI: 10.1186/s13018-024-04727-7] [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: 01/11/2024] [Accepted: 04/06/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The mechanotransduction mechanisms by which cells regulate tissue remodeling are not fully deciphered. Circular RNAs (circRNAs) are crucial to various physiological processes, including cell cycle, differentiation, and polarization. However, the effects of mechanical force on circRNAs and the role of circRNAs in the mechanobiology of differentiation and remodeling in stretched periodontal ligament stem cells (PDLSCs) remain unclear. This article aims to explore the osteogenic function of mechanically sensitive circular RNA protein kinase D3 (circPRKD3) and elucidate its underlying mechanotransduction mechanism. MATERIALS AND METHODS PDLSCs were elongated with 8% stretch at 0.5 Hz for 24 h using the Flexcell® FX-6000™ Tension System. CircPRKD3 was knockdown or overexpressed with lentiviral constructs or plasmids. The downstream molecules of circPRKD3 were predicted by bioinformatics analysis. The osteogenic effect of related molecules was evaluated by quantitative real-time PCR (qRT-PCR) and western blot. RESULTS Mechanical force enhanced the osteogenesis of PDLSCs and increased the expression of circPRKD3. Knockdown of circPRKD3 hindered PDLSCs from osteogenesis under mechanical force, while overexpression of circPRKD3 promoted the early osteogenesis process of PDLSCs. With bioinformatics analysis and multiple software predictions, we identified hsa-miR-6783-3p could act as the sponge of circPRKD3 to indirectly regulate osteogenic differentiation of mechanically stimulated PDLSCs. CONCLUSIONS Our results first suggested that both circPRKD3 and hsa-miR-6783-3p could enhance osteogenesis of stretched PDLSCs. Furthermore, hsa-miR-6783-3p could sponge circPRKD3 to indirectly regulate RUNX2 during the periodontal tissue remodeling process in orthodontic treatment.
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Affiliation(s)
- Jiani Liu
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Rui Liu
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Hong Wang
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Zijie Zhang
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Jixiao Wang
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, China
| | - Fulan Wei
- Department of Orthodontics, School and Hospital of Stomatology, Cheeloo College of Medicine, Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Research Center of Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases, No. 44-1 Wenhua Road West, Jinan, Shandong, 250012, China.
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Huang Y, Wu J, Zhan C, Liu R, Zhou Z, Huang X, Tian Y, Lin Z, Song Z. TRAF-STOP alleviates osteoclastogenesis in periodontitis. Front Pharmacol 2023; 14:1119847. [PMID: 37261283 PMCID: PMC10229065 DOI: 10.3389/fphar.2023.1119847] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 05/02/2023] [Indexed: 06/02/2023] Open
Abstract
The enhanced osteoclastogenesis contributes to alveolar bone resorption in periodontitis, which increases the risk of tooth loss. To reduce bone destruction, the inhibition of osteoclast development is proposed as a feasible treatment. CD40L-CD40-TRAF6 signal transduction plays a crucial role in inflammation, but how it regulates osteoclast activity in periodontitis has not been elucidated. In this study, we showed the potential role of CD40L-CD40-TRAF6 signaling in periodontitis. CD40L obviously promoted osteoclast formation and bone resorption capacity in vitro. Mechanistically, we found that osteoclastogenesis was enhanced by the overexpression of NFATc1 and NF-κB activation. Importantly, osteoclast activity was effectively suppressed by TRAF-STOP, a small molecular inhibitor of TRAF6. Furthermore, local injection of TRAF-STOP-loaded injectable PLGA-PEG-PLGA hydrogel could alleviate ligation-induced periodontitis in vivo. Taken together, TRAF-STOP shows promising clinical efficacy in periodontitis through alleviating osteoclastogenesis.
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Affiliation(s)
- Yaxian Huang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
| | - Jinyan Wu
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
| | - Chi Zhan
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
| | - Rong Liu
- School of Medicine, South China University of Technology, Guangzhou 510006, Guangzhou, China
| | - Zhaocai Zhou
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
| | - Xin Huang
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
| | - Yaguang Tian
- Department of Stomatology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou 570311, Hainan, China
| | - Zhengmei Lin
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
| | - Zhi Song
- Hospital of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou 510055, Guangzhou, China
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Burciaga SD, Saavedra F, Fischer L, Johnstone K, Jensen ED. Protein kinase D3 conditional knockout impairs osteoclast formation and increases trabecular bone volume in male mice. Bone 2023; 172:116759. [PMID: 37044359 DOI: 10.1016/j.bone.2023.116759] [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: 01/17/2023] [Revised: 03/15/2023] [Accepted: 04/04/2023] [Indexed: 04/14/2023]
Abstract
Studies using kinase inhibitors have shown that the protein kinase D (PRKD) family of serine/threonine kinases are required for formation and function of osteoclasts in culture. However, the involvement of individual protein kinase D genes and their in vivo significance to skeletal dynamics remains unclear. In the current study we present data indicating that protein kinase D3 is the primary form of PRKD expressed in osteoclasts. We hypothesized that loss of PRKD3 would impair osteoclast formation, thereby decreasing bone resorption and increasing bone mass. Conditional knockout (cKO) of Prkd3 using a murine Cre/Lox system driven by cFms-Cre revealed that its loss in osteoclast-lineage cells reduced osteoclast differentiation and resorptive function in culture. Examination of the Prkd3 cKO mice showed that bone parameters were unaffected in the femur at 4 weeks of age, but consistent with our hypothesis, Prkd3 conditional knockout resulted in 18 % increased trabecular bone mass in male mice at 12 weeks and a similar increase at 6 months. These effects were not observed in female mice. As a further test of our hypothesis, we asked if Prkd3 cKO could protect against bone loss in a ligature-induced periodontal disease model but did not see any reduction in bone destruction in this system. Together, our data indicate that PRKD3 promotes osteoclastogenesis both in vitro and in vivo.
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Affiliation(s)
- Samuel D Burciaga
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Flavia Saavedra
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Lori Fischer
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Karen Johnstone
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Eric D Jensen
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA.
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Meyers CMG, Burciaga SD, Faulkner B, Kazemi P, Cohn JM, Mansky KC, Jensen ED. Histone deacetylase 5 is a phosphorylation substrate of protein kinase D in osteoclasts. Bone 2022; 159:116393. [PMID: 35318161 PMCID: PMC9035101 DOI: 10.1016/j.bone.2022.116393] [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: 08/31/2021] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 11/24/2022]
Abstract
Protein kinase D (PRKD) family kinases are required for formation and function of osteoclasts. However, the substrates of PRKD in osteoclasts are unknown. To identify PRKD-dependent protein phosphorylation in osteoclasts, we performed a quantitative LC-MS/MS phosphoproteomics screen for proteins showing differential phosphorylation in osteoclasts after treatment with the PRKD inhibitor CRT0066101. We identified 757 phosphopeptides showing significant changes following PRKD inhibition. Among the changes, we found a group of 13 proteins showing decreased phosphorylation at PRKD consensus phosphorylation motifs. This group includes histone deacetylase 5 (HDAC5), which is a previously validated PRKD target. Considering this known interaction, work suggesting HDACs may be important regulators of osteoclasts, and studies suggesting potential functional redundancy between HDACs, we further investigated the relationship between PRKD and class IIa HDACs in osteoclasts. We confirmed that CRT0066101 inhibits phosphorylation of endogenous HDAC5 and to a lesser extent HDAC4, whereas HDAC7 phosphorylation was not affected. Osteoclast cultures from Hdac5 global knockout mice displayed impaired differentiation and reduced ability to resorb bone, while conditional knockout of Hdac4 in osteoclasts showed no phenotype in vitro or in vivo. The inhibitory effect of CRT0066101 was reduced in Hdac5 KO osteoclasts. Together these data indicate that the PRKD/HDAC5 axis contributes to osteoclast formation in vitro and suggest that this pathway may contribute to regulation of skeletal dynamics in vivo.
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Affiliation(s)
- Carina Mello Guimaraes Meyers
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Samuel D Burciaga
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Bora Faulkner
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Parandis Kazemi
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Jacob M Cohn
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Kim C Mansky
- Department of Developmental and Surgical Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA
| | - Eric D Jensen
- Department of Diagnostic & Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA.
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Chen J, Die L, Chen H, Zhang P. Effect of protein kinase D inhibitor CRT0066101 on the cell migration of salivary adenoid cystic carcinoma. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2022; 40:320-327. [PMID: 38597014 PMCID: PMC9207802 DOI: 10.7518/hxkq.2022.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 04/10/2022] [Indexed: 01/24/2023]
Abstract
OBJECTIVES This study aimed to study the effect of the protein kinase D (PKD) inhibitor CRT0066101 on the cell migration of salivary adenoid cystic carcinoma (SACC) cells in vitro and explore its related mechanisms to provide new strategies into the clinical treatment of SACC cells. METHODS SACC-LM cells were treated with different concentrations of CRT0066101, and the effect of active phospho-PKD was detected through Western blot and cell immunofluorescence staining. Transwell assay was performed to test cell migration. The effect of CRT0066101 on the protein expression related to the epithelial mesenchymal transition (EMT) was detected through Western blot, cell immunofluorescence staining, and quantitative real-time polymerase chain reaction (qRT-PCR). The cells were treated with the proteasome inhibitor after CRT0066101 administration, and the expression of Snail protein was detected by Western blot. RESULTS CRT0066101 inhibited PKD activity and reduced the number of invaded cells in SACC-LM cells. CRT0066101 decreased the expression of N-cadherin and Snail and increased the expression of E-cadherin in SACC-LM cells. The regulation of snail protein degradation by CRT0066101 was dependent on the proteasome pathway. CONCLUSIONS CRT0066101 can inhibit the migration of SACC-LM cells in SACC and regulate the expression of proteins and genes related to EMT. The mechanism may be associated with the proteasome-dependent degradation of Snail.
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Affiliation(s)
- Jiao Chen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Lü Die
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Hongli Chen
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Ping Zhang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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Lv D, Chen H, Feng Y, Cui B, Kang Y, Zhang P, Luo M, Chen J. Small-Molecule Inhibitor Targeting Protein Kinase D: A Potential Therapeutic Strategy. Front Oncol 2021; 11:680221. [PMID: 34249722 PMCID: PMC8263921 DOI: 10.3389/fonc.2021.680221] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 06/07/2021] [Indexed: 02/05/2023] Open
Abstract
The protein kinase D (PKD) family is a family of serine-threonine kinases that are members of the calcium/calmodulin-dependent kinase (CaMK) superfamily. PKDs have been increasingly implicated in multiple pivotal cellular processes and pathological conditions. PKD dysregulation is associated with several diseases, including cancer, inflammation, and obesity. Over the past few years, small-molecule inhibitors have emerged as alternative targeted therapy with fewer adverse side effects than currently available chemotherapy, and these specifically targeted inhibitors limit non-specific toxicities. The successful development of PKD inhibitors would significantly suppress the growth and proliferation of various cancers and inhibit the progression of other diseases. Various PKD inhibitors have been studied in the preclinical setting. In this context, we summarize the PKD inhibitors under investigation and their application for different kinds of diseases.
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Affiliation(s)
- Die Lv
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hongli Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yun Feng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Bomiao Cui
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yingzhu Kang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ping Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Min Luo
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jiao Chen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Kim HY, Park JH, Kim MJ, Lee JH, Oh SH, Byun JH. The effects of VEGF-centered biomimetic delivery of growth factors on bone regeneration. Biomater Sci 2021; 9:3675-3691. [PMID: 33899852 DOI: 10.1039/d1bm00245g] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
It is accepted that biomimetic supply of signaling molecules during bone regeneration can provide an appropriate environment for accelerated new bone formation. In this study, we developed a growth factor delivery system based on porous particles and a thermosensitive hydrogel that allowed fast, continuous, and delayed/continuous release of growth factors to mimic their biological production during bone regeneration. It was observed that the Continuous group (continuous release of growth factors) provides a better environment for the osteogenic differentiation of hPDCs than the Biomimetic group (biomimetic release of growth factors), and thus is anticipated to promote bone regeneration. However, contrary to expectation, the Biomimetic group promoted significant new bone formation compared to the Continuous group. From the systematic cell culture experiments, the initial supply of VEGF was considered to have more favorable effects on the osteoclastogenesis than osteogenesis, which may hinder bone regeneration. Our results indicated that the continuous supply of VEGF (in particular, at early stage) from VEGF-loaded biomaterial might not be conducive to new bone formation. Therefore, we suggest that a biomimetic supply of growth factors is a more pivotal parameter for sufficient tissue regeneration. Its use as a molecular delivery system may also serve as a useful tool for the investigation of biological processes and molecules during tissue regeneration processes.
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Affiliation(s)
- Ho Yong Kim
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Republic of Korea.
| | - Jin-Ho Park
- Department of Oral and Maxillofacial Surgery, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Institute of Health Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea. and Department of Convergence Medical Science, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Institute of Health Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Min Ji Kim
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Republic of Korea.
| | - Jin Ho Lee
- Department of Advanced Materials, Hannam University, Daejeon 34054, Republic of Korea
| | - Se Heang Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Republic of Korea.
| | - June-Ho Byun
- Department of Oral and Maxillofacial Surgery, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Institute of Health Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea. and Department of Convergence Medical Science, Gyeongsang National University School of Medicine, Gyeongsang National University Hospital, Institute of Health Sciences, Gyeongsang National University, Jinju, 52828, Republic of Korea
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Povoroznyuk VV, Dedukh NV, Bystrytska MA, Shapovalov VS. Bone remodeling stages under physiological conditions and glucocorticoid in excess: Focus on cellular and molecular mechanisms. REGULATORY MECHANISMS IN BIOSYSTEMS 2021. [DOI: 10.15421/022130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
This review provides a rationale for the cellular and molecular mechanisms of bone remodeling stages under physiological conditions and glucocorticoids (GCs) in excess. Remodeling is a synchronous process involving bone resorption and formation, proceeding through stages of: (1) resting bone, (2) activation, (3) bone resorption, (4) reversal, (5) formation, (6) termination. Bone remodeling is strictly controlled by local and systemic regulatory signaling molecules. This review presents current data on the interaction of osteoclasts, osteoblasts and osteocytes in bone remodeling and defines the role of osteoprogenitor cells located above the resorption area in the form of canopies and populating resorption cavities. The signaling pathways of proliferation, differentiation, viability, and cell death during remodeling are presented. The study of signaling pathways is critical to understanding bone remodeling under normal and pathological conditions. The main signaling pathways that control bone resorption and formation are RANK / RANKL / OPG; M-CSF – c-FMS; canonical and non-canonical signaling pathways Wnt; Notch; MARK; TGFβ / SMAD; ephrinB1/ephrinB2 – EphB4, TNFα – TNFβ, and Bim – Bax/Bak. Cytokines, growth factors, prostaglandins, parathyroid hormone, vitamin D, calcitonin, and estrogens also act as regulators of bone remodeling. The role of non-encoding microRNAs and long RNAs in the process of bone cell differentiation has been established. MicroRNAs affect many target genes, have both a repressive effect on bone formation and activate osteoblast differentiation in different ways. Excess of glucocorticoids negatively affects all stages of bone remodeling, disrupts molecular signaling, induces apoptosis of osteocytes and osteoblasts in different ways, and increases the life cycle of osteoclasts. Glucocorticoids disrupt the reversal stage, which is critical for the subsequent stages of remodeling. Negative effects of GCs on signaling molecules of the canonical Wingless (WNT)/β-catenin pathway and other signaling pathways impair osteoblastogenesis. Under the influence of excess glucocorticoids biosynthesis of biologically active growth factors is reduced, which leads to a decrease in the expression by osteoblasts of molecules that form the osteoid. Glucocorticoids stimulate the expression of mineralization inhibitor proteins, osteoid mineralization is delayed, which is accompanied by increased local matrix demineralization. Although many signaling pathways involved in bone resorption and formation have been discovered and described, the temporal and spatial mechanisms of their sequential turn-on and turn-off in cell proliferation and differentiation require additional research.
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