Z Li1, K Zhang2, X Li3, H Pan4, S Li5, F Chen6, J Zhang7, Z Zheng8, J Wang9, H Liu10. 1. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: sdlizemin@163.com. 2. Department of Orthopedic Surgery, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, 519000, China. Electronic address: 05213381@163.com. 3. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: 858330676@qq.com. 4. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: panhehai@foxmail.com. 5. Department of Orthopedic Surgery, Guangzhou Chest Hospital, Guangzhou, 510080, China. Electronic address: lisbylee@qq.com. 6. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: 476268201@qq.com. 7. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: zhangjianspine@163.com. 8. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: zhengzm1@163.com. 9. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: zzuwjr@163.com. 10. Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: liuhui58@mail.sysu.edu.cn.
Abstract
OBJECTIVE: This study was to investigate the molecular role of Wnt5a on inflammation-driven intervertebral disc degeneration (IVDD). METHODS: The expression of Wnt5a was analyzed in human nucleus pulposus (NP) tissues with immunohistochemical staining. The effects of Wnt5a on matrix production were assessed by RT-qPCR and western blotting. Small interfering RNAs (siRNAs), promoter deletion assay, and promoter binding site mutant were used to reveal the molecular role of Wnt5a in TNF-α-induced matrix metalloproteinase (MMP) expression. The regulatory effects of TNF-α on Wnt5a were investigated with pharmachemical inhibitors and siRNA experiment. RESULTS: The expression of Wnt5a was elevated in moderately degenerated human NP tissue with similar expression pattern of TNF-α. In NP cells, Wnt5a significantly increased aggrecan and collagen II expression. Inhibition of JNK or interfering Sox9 gene expression significantly suppressed Wnt5a-induced matrix production. AP-1(JunB) binding sites were located in Sox9 promoter and mutation of these sites sabotaged Wnt5a-induced Sox9 up-regulation and subsequent matrix genes expression. Notably, Wnt5a, which was induced by TNF-α, on the other way round suppressed TNF-α-NF-κB (p65) signaling and subsequent MMPs expression. In vivo studies with MR imaging confirmed the protective role of Wnt5a in IVDD. CONCLUSIONS: Wnt5a, which can be induced by TNF-α, increased matrix production in a Sox9-dependent manner through the activation of JNK-AP1 (JunB) signaling, and antagonized TNF-α-induced up-regulation of MMPs through the inhibition of NF-κB signaling. It indicates that Wnt5a suppresses IVDD through a TNF-α/NF-κB-Wnt5a negative-feedback loop.
OBJECTIVE: This study was to investigate the molecular role of Wnt5a on inflammation-driven intervertebral disc degeneration (IVDD). METHODS: The expression of Wnt5a was analyzed in human nucleus pulposus (NP) tissues with immunohistochemical staining. The effects of Wnt5a on matrix production were assessed by RT-qPCR and western blotting. Small interfering RNAs (siRNAs), promoter deletion assay, and promoter binding site mutant were used to reveal the molecular role of Wnt5a in TNF-α-induced matrix metalloproteinase (MMP) expression. The regulatory effects of TNF-α on Wnt5a were investigated with pharmachemical inhibitors and siRNA experiment. RESULTS: The expression of Wnt5a was elevated in moderately degenerated human NP tissue with similar expression pattern of TNF-α. In NP cells, Wnt5a significantly increased aggrecan and collagen II expression. Inhibition of JNK or interfering Sox9 gene expression significantly suppressed Wnt5a-induced matrix production. AP-1(JunB) binding sites were located in Sox9 promoter and mutation of these sites sabotaged Wnt5a-induced Sox9 up-regulation and subsequent matrix genes expression. Notably, Wnt5a, which was induced by TNF-α, on the other way round suppressed TNF-α-NF-κB (p65) signaling and subsequent MMPs expression. In vivo studies with MR imaging confirmed the protective role of Wnt5a in IVDD. CONCLUSIONS:Wnt5a, which can be induced by TNF-α, increased matrix production in a Sox9-dependent manner through the activation of JNK-AP1 (JunB) signaling, and antagonized TNF-α-induced up-regulation of MMPs through the inhibition of NF-κB signaling. It indicates that Wnt5a suppresses IVDD through a TNF-α/NF-κB-Wnt5a negative-feedback loop.
Authors: Lorenzo M Fernandes; Nazir M Khan; Camila M Trochez; Meixue Duan; Martha E Diaz-Hernandez; Steven M Presciutti; Greg Gibson; Hicham Drissi Journal: Sci Rep Date: 2020-09-17 Impact factor: 4.379