Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, #1 Tian Tan Xi Li, Beijing 100050, China.
Exp Cell Res. 2012 Dec 10;318(20):2592-603. doi: 10.1016/j.yexcr.2012.08.008. Epub 2012 Sep 10.
Inflammatory mediators including inducible nitric oxide (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α) and Interleukin-6 (IL-6) contribute to the course of a variety of inflammatory diseases. S632A3 is a new member of the glutarimide antibiotics isolated from a cultured broth of Streptomyces hygroscopicus S632 with a potent NF-κB inhibitory activity. In the present study, we investigated the anti-inflammatory effects and the underlying molecular mechanism of S632A3 on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. S632A3 concentration-dependently inhibited LPS-induced NO and prostaglandin E(2) (PGE(2)) production through the suppression of iNOS and COX-2 at gene transcription levels. In addition, S632A3 suppressed NF-κB-dependent inflammatory responses by inhibiting the activation of glycogen synthase kinase 3β (GSK-3β), while the activation of IκB kinase (IKK) complex was unaffected. S632A3 suppressed NF-κB activity by differentially affecting the CREB (cAMP response element-binding protein) and NF-κB p65 interacting with the coactivator CBP (CREB binding protein). S632A3 also inhibited GSK-3β-elicited iNOS and COX-2 expression. Moreover, S632A3 was shown to inhibit the activation of ASK1 (Apoptosis-signal regulating kinase 1) and p38 mitogen-activated protein kinase, therefore attenuated the LPS-induced NF-κB activity in macrophages. Furthermore, S632A3 significantly reduced the pro-inflammatory cytokines TNF-α and IL-6 production while increased the anti-inflammatory cytokine IL-10 production in LPS-stimulated RAW264.7 cells. Our study thus provides a molecular mechanism by which S632A3 inhibited LPS-induced pro-inflammatory response in macrophages through interfering with the activation of GSK-3β and ASK1-p38 signaling.
炎症介质，包括诱导型一氧化氮合酶（iNOS）、环氧化酶-2（COX-2）、肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6），参与了多种炎症性疾病的发生发展过程。S632A3 是一种新型的戊二酰亚胺类抗生素，从吸水链霉菌 S632 的发酵液中分离得到，具有很强的 NF-κB 抑制活性。在本研究中，我们研究了 S632A3 对脂多糖（LPS）刺激的 RAW264.7 巨噬细胞的抗炎作用及其潜在的分子机制。S632A3 呈浓度依赖性地抑制 LPS 诱导的 NO 和前列腺素 E2（PGE2）的产生，其作用机制是通过抑制 iNOS 和 COX-2 的基因转录水平。此外，S632A3 通过抑制糖原合酶激酶 3β（GSK-3β）的激活，抑制 NF-κB 依赖性炎症反应，而 IκB 激酶（IKK）复合物的激活不受影响。S632A3 通过影响 CREB（cAMP 反应元件结合蛋白）和 NF-κB p65 与共激活子 CBP（CREB 结合蛋白）的相互作用，来抑制 NF-κB 活性。S632A3 还抑制 GSK-3β 诱导的 iNOS 和 COX-2 表达。此外，S632A3 抑制 ASK1（凋亡信号调节激酶 1）和 p38 丝裂原活化蛋白激酶的激活，从而减弱了 LPS 诱导的巨噬细胞中的 NF-κB 活性。此外，S632A3 显著降低 LPS 刺激的 RAW264.7 细胞中促炎细胞因子 TNF-α和 IL-6 的产生，同时增加抗炎细胞因子 IL-10 的产生。因此，本研究提供了一个分子机制，即 S632A3 通过干扰 GSK-3β 和 ASK1-p38 信号通路的激活，抑制 LPS 诱导的巨噬细胞的促炎反应。
