Chen Ran, Tan Ya, Li Yang, Huang Junlan, Kuang Liang, Ni Zhenhong, Lan Haiyang, Long Rui, Xie Yangli, Chen Hangang, Luo Xiaoqing, Chen Lin, Tang Ying, Zhou Siru
War Trauma Medical Center, State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical Center, Daping Hospital, Army Medical University, Chongqing, 40038, People's Republic of China.
Department of Hematology, Southwest Hospital, First Affiliated Hospital of the Army Medical University, Chongqing, 40038, People's Republic of China.
J Orthop Translat. 2022 Oct 6;36:164-176. doi: 10.1016/j.jot.2022.09.009. eCollection 2022 Sep.
Vismodegib, as an exogenous Indian hedgehog (Ihh) antagonist, has been approved by the Food and Drug Administration (FDA) for the clinical treatment of patients with basal cell carcinoma, and previous observations implicate the potential therapeutic of vismodegib in osteoarthritis treatment. However, there is no direct evidence for the role of Ihh signaling in intervertebral discs (IVDs) homeostasis of adult mice. The aim of the present study is to assess the effect of systemic administration of Smoothened inhibitor (SMOi) - vismodegib on IVDs homeostasis during the adult stage.
The expression of glioma-associated oncogene homolog 1 (Gli1), the downstream targeting gene of Ihh signaling, in IVDs of adult mice after receiving systemic administration of SMOi was examined by immunohistochemistry. The pathological changes of vertebral bodies after SMOi treatment were evaluated by X-ray and micro-CT. The effects of SMOi on homeostasis of IVDs including cartilaginous endplates (CEP), growth plates (GP) and annulus fibrous (AF) were evaluated by histological analysis. The expressions of Aggrecan, Matrix metalloproteinase 13 (MMP13) and Runt-related transcription factor 2 (Runx2), in IVDs were also investigated by immunohistochemistry. Changes in chondrocyte apoptosis and proliferation in IVDs were evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and analyzing the expression of the cell proliferation antigen Ki-67.
Systemic administration of SMOi significantly decreased the expression of Gli1 in IVDs that indicating effective inhibition of Ihh signaling. Bone mass of vertebral bodies was diminished after SMOi treatment. Moreover, IVDs degeneration (IDD) like defects including CEP sclerosis, degenerative nucleus pulposus (NP) and fissure within AF, as well as narrowed or fused GP and loss bone mass of vertebral bodies was observed in SMOi-treated mice. The severity of IDD was time-dependent with the administration of SMOi treatment after 2-8 weeks. The expressions of Aggrecan, MMP13 and Runx2 in IVDs of mice receiving SMOi treatment were significantly decreased. In addition, chondrocyte apoptosis was significantly enhanced, while chondrocyte proliferation was significantly inhibited.
Our study propose that systemic administration of vismodegib damages IVDs homeostasis via inhibition of Ihh signaling in adult mice. The clinical application of Ihh signaling antagonists such as vismodegib should be careful considering these side adverse.
Vismodegib as an exogenous antagonist of Ihh signaling has been approved by the FDA for the clinical treatment of patients with basal cell carcinoma. However, it is still unknown whether vismodegib will has adverse effects on the patient or animal model of IVDs cartilage homeostasis. Based on our study, systemic administration of vismodegib damages IVDs homeostasis via inhibition of Ihh signaling in adult mice and special attention should be paid to the clinical application of vismodegib.
维莫德吉作为一种外源性印度刺猬因子（Ihh）拮抗剂，已获美国食品药品监督管理局（FDA）批准用于基底细胞癌患者的临床治疗，且先前的观察表明维莫德吉在骨关节炎治疗中具有潜在治疗作用。然而，尚无直接证据表明Ihh信号在成年小鼠椎间盘（IVD）内稳态中的作用。本研究旨在评估全身给予 smoothened 抑制剂（SMOi）——维莫德吉对成年期 IVD 内稳态的影响。
通过免疫组织化学检测成年小鼠全身给予 SMOi 后，IVD 中 Ihh 信号下游靶向基因胶质瘤相关癌基因同源物 1（Gli1）的表达。通过 X 射线和显微 CT 评估 SMOi 治疗后椎体的病理变化。通过组织学分析评估 SMOi 对 IVD 内稳态的影响，包括软骨终板（CEP）、生长板（GP）和纤维环（AF）。还通过免疫组织化学研究 IVD 中聚集蛋白聚糖、基质金属蛋白酶 13（MMP13）和 runt 相关转录因子 2（Runx2）的表达。通过末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）测定法并分析细胞增殖抗原 Ki-67 的表达，评估 IVD 中软骨细胞凋亡和增殖的变化。
全身给予 SMOi 显著降低了 IVD 中 Gli1 的表达，表明 Ihh 信号被有效抑制。SMOi 治疗后椎体骨量减少。此外，在接受 SMOi 治疗的小鼠中观察到类似 IVD 退变（IDD）的缺陷，包括 CEP 硬化、退变的髓核（NP）和 AF 内的裂隙，以及 GP 变窄或融合和椎体骨量丢失。IDD 的严重程度与 SMOi 治疗 2 - 8 周后的给药时间有关。接受 SMOi 治疗的小鼠 IVD 中聚集蛋白聚糖、MMP13 和 Runx2 的表达显著降低。此外，软骨细胞凋亡显著增强，而软骨细胞增殖显著受抑制。
我们的研究表明，全身给予维莫德吉通过抑制成年小鼠的 Ihh 信号损害 IVD 内稳态。在考虑这些不良副作用的情况下，应谨慎临床应用 Ihh 信号拮抗剂如维莫德吉。
维莫德吉作为 Ihh 信号的外源性拮抗剂已获 FDA 批准用于基底细胞癌患者的临床治疗。然而，维莫德吉是否会对 IVD 软骨内稳态的患者或动物模型产生不良影响仍不清楚。基于我们的研究，全身给予维莫德吉通过抑制成年小鼠的 Ihh 信号损害 IVD 内稳态，在维莫德吉的临床应用中应予以特别关注。
