Downregulation of Krüppel-like factor 15 expression delays endochondral bone ossification during fracture healing.

Autor: Tachibana S; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Hayashi S; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan. Electronic address: shayashi@med.kobe-u.ac.jp., Ikuta K; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Anjiki K; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Onoi Y; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Suda Y; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Wada K; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Maeda T; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Saito A; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Tsubosaka M; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Kamenaga T; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Kuroda Y; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Nakano N; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Matsumoto T; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan., Hosooka T; Laboratory of Nutritional Physiology, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan., Ogawa W; Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan., Kuroda R; Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
Jazyk: angličtina
Zdroj: Bone [Bone] 2025 Jan; Vol. 190, pp. 117302. Date of Electronic Publication: 2024 Oct 20.
DOI: 10.1016/j.bone.2024.117302
Abstrakt: Objective: The role of Krüppel-like zinc finger transcription factor 15 (KLF15) in endochondral ossification during fracture healing remains unexplored. In this study, we aimed to elucidate the impact of KLF15 in a mouse model of tibial transverse fracture.
Methods: We created tamoxifen-inducible, cartilage-specific KLF15 knockout mice (KLF15 KO). KLF15 fl/fl Col2-CreERT mice from the same litters as the KLF15 KO mice, but not treated with 4-hydroxytamoxifen, were used as controls (CT). At 10 weeks, male KLF15 KO and CT mice underwent tibial fracture followed by intramedullary nailing. Both groups were administered tamoxifen at days 0, 3, and 7 after surgery. The tibiae were harvested on post-surgery days 7, 10, and 14 for radiological assessment using micro-computed tomography. Histological staining (Safranin-O) and immunohistochemistry for KLF15, SOX9, Indian hedgehog (IHH), RUNX2, and Osterix were performed. Additionally, cartilage from mouse fetus was cultured for qRT-PCR and western blot analyses of KLF15, SOX9, IHH, Col2, RUNX2, Osterix, TGF-β, SMAD3, and phosphor-SMAD3.
Results: The radiological assessment revealed that immature callus formation was delayed in KLF15 KO, compared with that in CT, peaking on day 14 compared with that on day 10 in CT. KLF15 KO mice exhibited delayed fracture healing and reduced Safranin-O staining at days 7 and 10 post-surgery. The ratio of cells positive for KLF15 and SOX9 was significantly lower in KLF15 KO than in CT, whereas the ratios for IHH, RUNX2, and Osterix showed no significant difference. RT-PCR revealed reduced expression of KLF15, SOX9, and COL2, with no significant changes in IHH, Osterix, RUNX2, TGF-β, and SMAD3. Western blot analysis indicated decreased SMAD3 phosphorylation in KLF15 KO mice.
Conclusion: KLF15 regulates SOX9 via the TGF-β-SMAD3-SOX9 pathway, independent of IHH, in endochondral ossification. The KLF15 deficiency decreases SOX9 expression through reduced SMAD3 phosphorylation, subsequently delaying fracture healing.
Competing Interests: Declaration of competing interest The authors declare no conflicts of interest.
(Copyright © 2024 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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