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Hirata-Tsuchiya S, Suzuki S, Okamoto K, Saito N, Yuan H, Yamada S, Jimi E, Shiba H, Kitamura C. A small nuclear acidic protein (MTI-II, Zn 2+-binding protein, parathymosin) attenuates TNF-α inhibition of BMP-induced osteogenesis by enhancing accessibility of the Smad4-NF-κB p65 complex to Smad binding element. Mol Cell Biochem 2020; 469:133-142. [PMID: 32304006 DOI: 10.1007/s11010-020-03734-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 04/08/2020] [Indexed: 01/28/2023]
Abstract
Pro-inflammatory cytokines prevent bone regeneration in vivo and activation of nuclear factor-κB (NF-κB) signaling has been proposed to lead to suppression of bone morphogenetic protein (BMP)-induced osteogenesis via direct binding of p65 to Smad4 in vitro. Application of a small nuclear acidic protein (MTI-II) and its delivered peptide, MPAID (MTI-II peptide anti-inflammatory drug) has been described to elicit therapeutic potential via strong anti-inflammatory action following the physical association of MTI-II and MPAID with p65. However, it is unclear whether MTI-II attenuates tumor necrosis factor (TNF)-α inhibition of BMP-induced osteogenesis. Herein, we found that TNF-α-mediated suppression of responses associated with BMP4-induced osteogenesis, including expression of the osteocalcin encoding gene Ocn, Smad binding element (SBE)-dependent luciferase activity, alkaline phosphatase activity, and alizarin red S staining were largely restored by MTI-II and MPAID in MC3T3-E1 cells. Mechanistically, MTI-II and MPAID did not inhibit nuclear translocation of p65 or disassociate Smad4 from p65. Further, results from chromatin immunoprecipitation (ChIP) analyses revealed that Smad4 enrichment in cells over-expressing MTI-II and treated with TNF-α was equivalent to that in cells without TNF-α treatment. Alternatively, Smad4 enrichment was considerably decreased following TNF-α treatment in control cells. Moreover, p65 enrichment in the Id-1 promoter SBE was detected only when cells over-expressing MTI-II were stimulated with TNF-α. Overall, our study concludes that MTI-II restored TNF-α-inhibited suppression of BMP-Smad-induced osteogenic differentiation by enhancing accessibility of the Smad4-p65 complex to the SBE rather than by liberating Smad4 from p65.
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Affiliation(s)
- Shizu Hirata-Tsuchiya
- Department of Biological Endodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, 734-8553, Japan.,Division of Endodontics and Restorative Dentistry, Department of Oral Function, Kyushu Dental University, Fukuoka, 803-8580, Japan
| | - Shigeki Suzuki
- Department of Biological Endodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, 734-8553, Japan. .,Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan.
| | - Kazuki Okamoto
- The Institute of Scientific and Industrial Research, Osaka University, Osaka, 567-0047, Japan
| | - Noriko Saito
- Department of Biological Endodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, 734-8553, Japan
| | - Hang Yuan
- Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Satoru Yamada
- Department of Periodontology and Endodontology, Tohoku University Graduate School of Dentistry, 4-1, Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Eijiro Jimi
- Oral Health/Brain Health/Total Health Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hideki Shiba
- Department of Biological Endodontics, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, 734-8553, Japan
| | - Chiaki Kitamura
- Division of Endodontics and Restorative Dentistry, Department of Oral Function, Kyushu Dental University, Fukuoka, 803-8580, Japan
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