The First Department of Orthopaedic Surgery, The First Hospital of Tianshui, Tianshui, Gansu, 741000, China.
Department of Odermatology, The First Hospital of Tianshui, Tianshui, Gansu, 741000, China.
J Orthop Surg Res. 2024 Apr 16;19(1):244. doi: 10.1186/s13018-024-04702-2.
Ossification of ligamentum flavum (OLF) is a prevalent degenerative spinal disease, typically causing severe neurological dysfunction. Kruppel-like factor 5 (KLF5) plays an essential role in the regulation of skeletal development. However, the mechanism KLF5 plays in OLF remains unclear, necessitating further investigative studies.
qRT-PCR, immunofluorescent staining and western blot were used to measure the expression of KLF5. Alkaline Phosphatase (ALP) staining, Alizarin red staining (ARS), and the expression of Runt-related transcription factor 2 (RUNX2), osteopontin (OPN), and osteocalcin (OCN) were used to evaluate the osteogenic differentiation. Luciferase activity assay and ChIP-PCR were performed to investigate the molecular mechanisms.
KLF5 was significantly upregulated in OLF fibroblasts in contrast to normal ligamentum flavum (LF) fibroblasts. Silencing KLF5 diminished osteogenic markers and mineralized nodules, while its overexpression had the opposite effect, confirming KLF5's role in promoting ossification. Moreover, KLF5 promotes the ossification of LF by activating the transcription of Connexin 43 (CX43), and overexpressing CX43 could reverse the suppressive impact of KLF5 knockdown on OLF fibroblasts' osteogenesis.
KLF5 promotes the OLF by transcriptionally activating CX43. This finding contributes significantly to our understanding of OLF and may provide new therapeutic targets.
黄韧带骨化（OLF）是一种常见的退行性脊柱疾病，通常会导致严重的神经功能障碍。Krüppel 样因子 5（KLF5）在骨骼发育的调控中起着至关重要的作用。然而，KLF5 在 OLF 中所起的作用机制尚不清楚，需要进一步的研究。
qRT-PCR、免疫荧光染色和 Western blot 用于测量 KLF5 的表达。碱性磷酸酶（ALP）染色、茜素红染色（ARS）以及 runt 相关转录因子 2（RUNX2）、骨桥蛋白（OPN）和骨钙素（OCN）的表达用于评估成骨分化。荧光素酶活性测定和 ChIP-PCR 用于研究分子机制。
与正常黄韧带（LF）成纤维细胞相比，OLF 成纤维细胞中 KLF5 的表达显著上调。沉默 KLF5 降低了成骨标志物和矿化结节的表达，而过表达则产生相反的效果，证实了 KLF5 在促进骨化中的作用。此外，KLF5 通过激活连接蛋白 43（CX43）的转录促进 LF 的骨化，而过表达 CX43 可以逆转 KLF5 敲低对 OLF 成纤维细胞成骨作用的抑制作用。
KLF5 通过转录激活 CX43 促进 OLF 的发生。这一发现对我们理解 OLF 具有重要意义，并可能为新的治疗靶点提供依据。
