Rapamycin mitigates inflammation-mediated disc matrix homeostatic imbalance by inhibiting mTORC1 and inducing autophagy through Akt activation.
Rapamycin mitigates inflammation-mediated disc matrix homeostatic imbalance by inhibiting mTORC1 and inducing autophagy through Akt activation.
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DOI：
10.1002/jsp2.1303
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发表时间：
2024-03
期刊：
影响因子：
3.7
通讯作者：
Vo, Nam V.
中科院分区：
文献类型：
--
作者：
Yurube, Takashi;Buchser, William J.;Zhang, Zhongying;Silwal, Prashanta;Lotze, Michael T.;Kang, James D.;Sowa, Gwendolyn A.;Vo, Nam V.
关键词：
腰痛是一个全球性的健康问题，主要源于椎间盘退变（IDD）。自噬受到磷脂酰肌醇 3 激酶 (PI3K)/Akt/哺乳动物雷帕霉素靶点 (mTOR) 信号通路的负调控，通过去除和回收受损的细胞成分来预防代谢和退行性疾病。尽管越来越多的证据表明自噬发生在椎间盘中，但对椎间盘细胞自噬的调节仍然知之甚少。使用源自健康雌性兔椎间盘的纤维环（rAF）细胞培养物来测试自噬抑制或激活对椎间盘细胞命运和基质稳态的影响。具体来说，使用包括雷帕霉素、3-甲基腺嘌呤、MK-2206和PP242在内的不同化学抑制剂来调节PI3K/Akt/mTOR信号通路中不同蛋白质的活性，以评估在营养不良培养条件下生长的rAF细胞中IL-1β诱导的细胞衰老、凋亡和基质稳态。雷帕霉素是 mTOR 复合物 1 (mTORC1) 的抑制剂，可降低 rAF 细胞培养物中 mTOR 及其效应子 p70/S6K 的磷酸化。雷帕霉素还诱导自噬流，通过增加关键自噬标记物的表达来测量，包括 LC3 斑点数、LC3-II 表达和细胞质 HMGB1 强度，并减少 p62/SQSTM1 表达。正如预期的那样，IL-1β 刺激促进 rAF 细胞衰老、凋亡和基质稳态失衡，并增强聚集蛋白分解以及 MMP-3 和 MMP-13 的表达。雷帕霉素治疗有效减轻了 IL-1β 介导的炎症应激变化，但雷帕霉素的这些缓解作用被 Akt 和 mTOR 复合物 2 (mTORC2) 的化学抑制所消除。这些发现表明，雷帕霉素通过抑制 mTORC1，通过依赖于 Akt 和 mTORC2 活性的 PI3K/Akt/mTOR 途径诱导自噬，从而减弱炎症对椎间盘细胞的不利影响。因此，我们的研究结果确定自噬、雷帕霉素和 PI3K/Akt/mTOR 信号传导是 IDD 治疗的潜在治疗靶点。我们的研究证明了磷脂酰肌醇 3-激酶/Akt/哺乳动物雷帕霉素靶标 (mTOR) 信号通路在调节营养和炎症应激下椎间盘细胞命运、存活和基质稳态中的重要性。雷帕霉素（图中显示为 Rap）通过抑制 mTOR 复合物 1 (mTORC1) 但不抑制 mTOR 复合物 2 (mTORC2) 来激活自噬并防止椎间盘细胞凋亡、衰老和细胞外基质降解，雷帕霉素的这种细胞保护作用似乎取决于 Akt 激活而不是自噬诱导。我们的研究结果确定自噬、雷帕霉素和 PI3K/Akt/mTOR 信号传导是治疗椎间盘退变的潜在治疗靶点。
Low back pain is a global health problem that originated mainly from intervertebral disc degeneration (IDD). Autophagy, negatively regulated by the phosphatidylinositol 3‐kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway, prevents metabolic and degenerative diseases by removing and recycling damaged cellular components. Despite growing evidence that autophagy occurs in the intervertebral disc, the regulation of disc cellular autophagy is still poorly understood. Annulus fibrosus (rAF) cell cultures derived from healthy female rabbit discs were used to test the effect of autophagy inhibition or activation on disc cell fate and matrix homeostasis. Specifically, different chemical inhibitors including rapamycin, 3‐methyladenine, MK‐2206, and PP242 were used to modulate activities of different proteins in the PI3K/Akt/mTOR signaling pathway to assess IL‐1β‐induced cellular senescence, apoptosis, and matrix homeostasis in rAF cells grown under nutrient‐poor culture condition. Rapamycin, an inhibitor of mTOR complex 1 (mTORC1), reduced the phosphorylation of mTOR and its effector p70/S6K in rAF cell cultures. Rapamycin also induced autophagic flux as measured by increased expression of key autophagy markers, including LC3 puncta number, LC3‐II expression, and cytoplasmic HMGB1 intensity and decreased p62/SQSTM1 expression. As expected, IL‐1β stimulation promoted rAF cellular senescence, apoptosis, and matrix homeostatic imbalance with enhanced aggrecanolysis and MMP‐3 and MMP‐13 expression. Rapamycin treatment effectively mitigated IL‐1β‐mediated inflammatory stress changes, but these alleviating effects of rapamycin were abrogated by chemical inhibition of Akt and mTOR complex 2 (mTORC2). These findings suggest that rapamycin blunts adverse effects of inflammation on disc cells by inhibiting mTORC1 to induce autophagy through the PI3K/Akt/mTOR pathway that is dependent on Akt and mTORC2 activities. Hence, our findings identify autophagy, rapamycin, and PI3K/Akt/mTOR signaling as potential therapeutic targets for IDD treatment. Our study demonstrates the importance of the phosphatidylinositol 3‐kinase/Akt/mammalian target of rapamycin (mTOR) signaling pathway in regulating disc cell fate, survival, and matrix homeostasis under nutritional and inflammatory stress. Rapamycin (shown as Rap in the figure) activates autophagy and protects against disc cellular apoptosis, senescence, and extracellular matrix degradation by inhibiting mTOR complex 1 (mTORC1) but not mTOR complex 2 (mTORC2), and this cell‐protective effects of rapamycin appear to depend on Akt activation rather than on autophagy induction. Our findings identify autophagy, rapamycin, and PI3K/Akt/mTOR signaling as potential therapeutic targets for treating intervertebral disc degeneration.
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DOI：
10.1146/annurev-pathol-121808-102144
发表时间：
2010
期刊：
Annual review of pathology
影响因子：
--
作者：
Coppé JP;Desprez PY;Krtolica A;Campisi J
通讯作者：
Campisi J
影响因子：
2.8
作者：
Hirata, Hiroaki;Yurube, Takashi;Nishida, Kotaro
通讯作者：
Nishida, Kotaro
DOI：
10.1073/pnas.92.20.9363
发表时间：
1995-09-26
影响因子：
11.1
作者：
DIMRI, GP;LEE, XH;CAMPISI, J
通讯作者：
CAMPISI, J
影响因子：
3
作者：
Gruber, Helen E.;Ingram, Jane A.;Hanley, Edward N., Jr.
通讯作者：
Hanley, Edward N., Jr.
影响因子：
3.9
作者：
Knight, Z. A.;Shokat, K. M.
通讯作者：
Shokat, K. M.