Wei Chao, Wang Xiaobin, Wu Siwen, Chen Yiyuan, Lai Shunxun, Liu Fubin, Wu Hailin, Lin Renqin, Li Jing
Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, China; Department of Spine Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, China.
Department of Spine Surgery, The Second Xiangya Hospital, Central South University, Changsha 410011, China.
Osteoarthritis Cartilage. 2025 May;33(5):560-573. doi: 10.1016/j.joca.2025.02.783. Epub 2025 Mar 6.
Beta-defensin 1 (DEFB1), is a member of the defensin family involved in inflammation, cell apoptosis and senescence. We hypothesized that DEFB1 is essential for intervertebral disc (IVD) homeostasis. Our objective was to elucidate the roles of DEFB1 in IVD degeneration (IDD).
DEFB1 expression in human degenerated and non-degenerated IVD tissues was measured. In the rat coccygeal IDD model, morphological changes and extracellular signal-regulated kinase 1/2 (ERK1/2) expression were assessed following DEFB1 knockdown lentivirus injection into rat tail discs. In vitro, DEFB1 knockdown or DEFB1-overexpressing plasmid was transfected into nucleus pulposus (NP) and annulus fibrosus (AF) cells. Under interleukin (IL)-1β stimulation, protein expression, cytokine levels, cell viability, cell senescence, cell apoptosis and cell cycle were evaluated.
IDD tissue from human and rat models exhibited higher DEFB1 levels compared to non-degenerated IVD samples. DEFB1 knockdown ameliorated histopathological changes and reduced inflammation in rat IVD tissues. Under IL-1β stimulation, DEFB1 knockdown increased cell viability (NP cells mean difference 0.28 [95% CI: 0.21, 0.35], AF cells 0.24 [0.20, 0.29]), and decreased cell senescence (-11.78 [-13.73, -9.83], -11.88 [-13.89, -9.87]), cell apoptosis (-9.15 [-11.20, -7.11], -7.40 [-9.36, -5.44]), and G1-phase arrest (-16.74 [-19.87, -13.61], -18.70 [-22.13, -15. 27]) in NP and AF cells. Conversely, DEFB1 overexpression had the opposite effects. DEFB1 knockdown reduced ERK1/2 phosphorylation in vivo and in vitro. The ERK antagonist ameliorated DEFB1 overexpression-induced changes in cellular phenotype.
DEFB1 knockdown ameliorated IDD features, potentially by regulating ERK signaling in NP and AF cells. Targeting DEFB1 could be a promising therapeutic strategy for IDD.
β-防御素1（DEFB1）是防御素家族的一员，参与炎症、细胞凋亡和衰老过程。我们假设DEFB1对椎间盘（IVD）内环境稳态至关重要。我们的目的是阐明DEFB1在椎间盘退变（IDD）中的作用。
检测人退变和未退变IVD组织中DEFB1的表达。在大鼠尾椎IDD模型中，向大鼠尾椎间盘注射DEFB1基因敲低慢病毒后，评估其形态学变化和细胞外信号调节激酶1/2（ERK1/2）的表达。在体外，将DEFB1基因敲低或过表达质粒转染到髓核（NP）和纤维环（AF）细胞中。在白细胞介素（IL）-1β刺激下，评估蛋白质表达、细胞因子水平、细胞活力、细胞衰老、细胞凋亡和细胞周期。
与未退变的IVD样本相比，人和大鼠模型的IDD组织中DEFB1水平更高。DEFB1基因敲低改善了大鼠IVD组织的组织病理学变化并减轻了炎症。在IL-1β刺激下，DEFB1基因敲低提高了细胞活力（NP细胞平均差异0.28 [95%可信区间：0.21，0.35]，AF细胞0.24 [0.20，0.29]），并降低了细胞衰老（-11.78 [-13.73，-9.83]，-11.88 [-13.89，-9.87]）、细胞凋亡（-9.15 [-11.20，-7.11]，-7.40 [-9.36，-5.44]）以及NP和AF细胞中的G1期阻滞（-16.74 [-19.87，-13.61]，-18.70 [-22.13，-15.27]）。相反，DEFB1过表达则产生相反的效果。DEFB1基因敲低在体内和体外均降低了ERK1/2的磷酸化水平。ERK拮抗剂改善了DEFB1过表达诱导的细胞表型变化。
DEFB1基因敲低改善了IDD特征，可能是通过调节NP和AF细胞中的ERK信号通路实现的。靶向DEFB1可能是一种有前景的IDD治疗策略。
