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Choi B, Kim JE, Park SO, Kim EY, Oh S, Choi H, Yoon D, Min HJ, Kim HR, Chang EJ. Sphingosine-1-phosphate hinders the osteogenic differentiation of dental pulp stem cells in association with AKT signaling pathways. Int J Oral Sci 2022; 14:21. [PMID: 35459199 PMCID: PMC9033766 DOI: 10.1038/s41368-022-00173-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 02/24/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) is an important lipid mediator that regulates a diverse range of intracellular cell signaling pathways that are relevant to tissue engineering and regenerative medicine. However, the precise function of S1P in dental pulp stem cells (DPSCs) and its osteogenic differentiation remains unclear. We here investigated the function of S1P/S1P receptor (S1PR)-mediated cellular signaling in the osteogenic differentiation of DPSCs and clarified the fundamental signaling pathway. Our results showed that S1P-treated DPSCs exhibited a low rate of differentiation toward the osteogenic phenotype in association with a marked reduction in osteogenesis-related gene expression and AKT activation. Of note, both S1PR1/S1PR3 and S1PR2 agonists significantly downregulated the expression of osteogenic genes and suppressed AKT activation, resulting in an attenuated osteogenic capacity of DPSCs. Most importantly, an AKT activator completely abrogated the S1P-mediated downregulation of osteoblastic markers and partially prevented S1P-mediated attenuation effects during osteogenesis. Intriguingly, the pro-inflammatory TNF-α cytokine promoted the infiltration of macrophages toward DPSCs and induced S1P production in both DPSCs and macrophages. Our findings indicate that the elevation of S1P under inflammatory conditions suppresses the osteogenic capacity of the DPSCs responsible for regenerative endodontics.
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Affiliation(s)
- Bongkun Choi
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Ji-Eun Kim
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Si-On Park
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Eun-Young Kim
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Soyoon Oh
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyuksu Choi
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Dohee Yoon
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyo-Jin Min
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea.,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Hyung-Ryong Kim
- Department of Pharmacology, College of Dentistry, Jeonbuk National University, Jeonju, Korea.
| | - Eun-Ju Chang
- Department of Biomedical Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 05505, Korea. .,Stem Cell Immunomodulation Research Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. .,Department of Biochemistry and Molecular Biology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
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Kalinkovich A, Livshits G. Biased and allosteric modulation of bone cell-expressing G protein-coupled receptors as a novel approach to osteoporosis therapy. Pharmacol Res 2021; 171:105794. [PMID: 34329703 DOI: 10.1016/j.phrs.2021.105794] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/20/2021] [Accepted: 07/25/2021] [Indexed: 12/16/2022]
Abstract
On the cellular level, osteoporosis (OP) is a result of imbalanced bone remodeling, in which osteoclastic bone resorption outcompetes osteoblastic bone formation. Currently available OP medications include both antiresorptive and bone-forming drugs. However, their long-term use in OP patients, mainly in postmenopausal women, is accompanied by severe side effects. Notably, the fundamental coupling between bone resorption and formation processes underlies the existence of an undesirable secondary outcome that bone anabolic or anti-resorptive drugs also reduce bone formation. This drawback requires the development of anti-OP drugs capable of selectively stimulating osteoblastogenesis and concomitantly reducing osteoclastogenesis. We propose that the application of small synthetic biased and allosteric modulators of bone cell receptors, which belong to the G-protein coupled receptors (GPCR) family, could be the key to resolving the undesired anti-OP drug selectivity. This approach is based on the capacity of these GPCR modulators, unlike the natural ligands, to trigger signaling pathways that promote beneficial effects on bone remodeling while blocking potentially deleterious effects. Under the settings of OP, an optimal anti-OP drug should provide fine-tuned regulation of downstream effects, for example, intermittent cyclic AMP (cAMP) elevation, preservation of Ca2+ balance, stimulation of osteoprotegerin (OPG) and estrogen production, suppression of sclerostin secretion, and/or preserved/enhanced canonical β-catenin/Wnt signaling pathway. As such, selective modulation of GPCRs involved in bone remodeling presents a promising approach in OP treatment. This review focuses on the evidence for the validity of our hypothesis.
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Affiliation(s)
- Alexander Kalinkovich
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 6905126, Israel
| | - Gregory Livshits
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 6905126, Israel; Adelson School of Medicine, Ariel University, Ariel 4077625, Israel.
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