Department of Spine Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541000, China.
Surgical Department, Affiliated Hospital of Youjiang Medical University for Nationality, Baise, 533000, China.
Inflammation. 2023 Oct;46(5):1697-1708. doi: 10.1007/s10753-023-01834-1. Epub 2023 Jun 6.
Ankylosing spondylitis (AS) is an autoimmune disease which associated with inflammation of the spinal joints. Enhanced osteogenic differentiation was observed in AS; however, the underlying mechanism remains undefined. A cohort of AS (n = 15) and patients with traumatic fracture (n = 15) were recruited to this study. Fibroblasts were isolated, and characterized by H&E and immunocytochemistry (ICC) analysis. The expression and secretion of key molecules were detected by qRT-PCR, western blot, immunofluorescence (IF), and ELISA. Calcium deposition and alkaline phosphatase (ALP) activity were monitored by Alizarin Red S and ALP staining. The direct association between Spi-1 proto-oncogene (SPI1) and toll-like receptor 5 (TLR5) promoter was assessed by ChIP assay. AS fibroblasts was successfully isolated and exhibited osteogenic differentiation potentials. SPI1 was elevated in AS fibroblasts, and silencing of SPI1 inhibited osteogenic differentiation of AS fibroblasts. Mechanistic study showed that SPI1 acted as a transcriptional activator of TLR5. Knockdown of TLR5 suppressed osteogenic differentiation of AS fibroblasts via nuclear factor kappa B (NF-κB) signaling. Rescue experiments revealed that overexpression of TLR5 reversed SPI1 knockdown-suppressed osteogenic differentiation via NF-κB signaling. SPI1 regulated the progression of AS by modulating TLR5 via NF-κB signaling.
强直性脊柱炎（AS）是一种自身免疫性疾病，与脊柱关节炎症有关。在 AS 中观察到增强的成骨分化；然而，其潜在机制尚不清楚。本研究招募了一组 AS（n=15）和外伤性骨折患者（n=15）。分离成纤维细胞，并通过 H&E 和免疫细胞化学（ICC）分析进行鉴定。通过 qRT-PCR、western blot、免疫荧光（IF）和 ELISA 检测关键分子的表达和分泌。通过茜素红 S 和 ALP 染色监测钙沉积和碱性磷酸酶（ALP）活性。通过 ChIP 测定评估 Spi-1 原癌基因（SPI1）和 Toll 样受体 5（TLR5）启动子之间的直接关联。成功分离出 AS 成纤维细胞，并表现出成骨分化潜能。AS 成纤维细胞中 SPI1 升高，沉默 SPI1 抑制 AS 成纤维细胞的成骨分化。机制研究表明，SPI1 作为 TLR5 的转录激活剂发挥作用。TLR5 的敲低通过核因子 kappa B（NF-κB）信号抑制 AS 成纤维细胞的成骨分化。挽救实验表明，TLR5 的过表达通过 NF-κB 信号逆转了 SPI1 敲低抑制的成骨分化。SPI1 通过 NF-κB 信号调节 TLR5 来调节 AS 的进展。
