Du Jiacheng, Xu Menglei, Kong Fanchen, Zhu Pengfei, Mao Yubo, Liu Yijie, Zhou Hong, Dong Zhongchen, Yu Zilin, Du Tong, Gu Ye, Wu Xiexing, Geng Dechun, Mao Haiqing
1Department of Orthopaedics, The First Affiliated Hospital of Soochow University, Suzhou, China.
2Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Orthopaedic Department of Tongji Hospital, School of Medicine, Tongji University, China.
Aging Dis. 2022 Apr 1;13(2):552-567. doi: 10.14336/AD.2021.1025. eCollection 2022 Apr.
Nucleus pulposus (NP) cell (NPC) senescence is one of the main causes of intervertebral disc degeneration (IVDD). However, the underlying mechanism of NPC senescence is still unclear. The cannabinoid type 2 receptor (CB2R) is a member of the cannabinoid system and plays an important role in antioxidative stress, anti-inflammatory and antisenescence activities. In this study, we used a hydrogen peroxide (HO)-induced NPC senescence model and a rat acupuncture IVDD model to explore the role of CB2R in IVDD in vitro and in vivo. First, we confirmed that the expression of p16INK4a in the NP tissues of IVDD patients and rat acupuncture IVDD models obviously increased accompanied by a decrease in CB2R expression. Subsequently, we found that activation of CB2R significantly reduced the number of SA-β-gal positive cells and suppressed the expression of p16INK4a and senescence-related secretory phenotypes [SASP, including matrix metalloproteinase 9 and 13 (MMP9, MMP13) and high mobility group protein b1 (HMGB1)]. In addition, activation of CB2R promoted the expression of collagen type II (Col-2) and SRY-Box transcription factor 9 (SOX9), inhibit the expression of collagen type X (Col-X), and restore the balance of extracellular matrix (ECM) metabolism. In addition, the AMPK/GSK3β pathway was shown to play an important role in CB2R regulation of NPC senescence. Inhibition of AMPK expression reversed the effect of JWH015 (a CB2R agonist). Finally, we further demonstrated that in the rat IVDD model, the AMPK/GSK3β pathway was involved in the regulation of CB2R on NPC senescence. In conclusion, our experimental results prove that CB2R plays an important role in NPC senescence. Activation of CB2R can delay NPC senescence, restore the balance of ECM metabolism, and attenuate IVDD.
髓核（NP）细胞（NPC）衰老为椎间盘退变（IVDD）的主要原因之一。然而，NPC衰老的潜在机制仍不清楚。2型大麻素受体（CB2R）是大麻素系统的成员，在抗氧化应激、抗炎和抗衰老活动中发挥重要作用。本研究采用过氧化氢（HO）诱导的NPC衰老模型和大鼠针刺IVDD模型，探讨CB2R在体外和体内IVDD中的作用。首先，我们证实IVDD患者和大鼠针刺IVDD模型NP组织中p16INK4a表达明显增加，同时CB2R表达降低。随后，我们发现激活CB2R可显著减少SA-β-半乳糖苷阳性细胞数量，抑制p16INK4a表达及衰老相关分泌表型[SASP，包括基质金属蛋白酶9和13（MMP9、MMP13）及高迁移率族蛋白b1（HMGB1）]。此外，激活CB2R可促进II型胶原（Col-2）和SRY盒转录因子9（SOX9）表达，抑制X型胶原（Col-X）表达，恢复细胞外基质（ECM）代谢平衡。此外，AMPK/GSK3β通路在CB2R对NPC衰老的调控中起重要作用。抑制AMPK表达可逆转JWH015（一种CB2R激动剂）的作用。最后，我们进一步证明在大鼠IVDD模型中，AMPK/GSK3β通路参与CB2R对NPC衰老的调控。总之，我们的实验结果证明CB2R在NPC衰老中起重要作用。激活CB2R可延缓NPC衰老，恢复ECM代谢平衡，减轻IVDD。
