神经药理及新药发现徐江平教授课题组于近日在ACS Chemical Neuroscience上发表了题为“Roflupram, a phosphodiesterase 4 inhibitior, suppresses inflammasome activation through autophagy in microglial cells.”的研究论文。该论文系课题组于2017年发表的第3篇1区论文。
该论文是在前期工作 (Neuropharmacology. 2017;116:260-269) 基础上进一步探讨PDE4抑制剂在中枢神经系统发挥抗炎作用的机制。研究借助多种自噬活动检测方法，我们发现PDE4抑制剂ROF能诱导小胶质细胞的自噬活动，减轻LPS+ATP和Aβ25-35激活的NLRP3炎性小体通路，且ROF的这一作用呈自噬依赖性。ROF可通过自噬性降解NLRP3炎性小体，减少cleaved caspase 1的水平，从而减少对pro-IL-1β的剪切。研究还利用小胶质细胞条件培养基，证实了ROF对N2a神经细胞凋亡和突触损伤的保护作用。该研究还在原代培养的小胶质细胞及在体动物模型上证实了ROF对自噬及神经炎症的调控作用。该论文系首次在中枢神经系统中证实PDE4抑制剂可以促进小胶质细胞的自噬，并将小胶质细胞的自噬与PDE4抑制剂减少IL-1β、抗神经炎症作用关联，发现了PDE4抑制剂抗神经炎症作用的新机制。
此论文受到国家自然科学基金面上项目、国家自然科学基金青年基金、国家自然科学基金-广东联合基金等基金资助。2013级博士研究生尤婷婷为本论文的第一作者，徐江平教授、汪海涛博士为该论文的共同通讯作者。ACS Chemical Neuroscience 为小类神经科学2区杂志，小类药物化学1区杂志，IF=3.883。
You T, Cheng YF, Zhong J, Bi B, Zeng B, Zheng W, Wang HT, Xu JP. Roflupram, a phosphodiesterase 4 inhibitior, suppresses inflammasome activation through autophagy in microglial cells. ACS Chem Neurosci. 2017 Jun 12. [Epub ahead of print]
Inhibition of phosphodiesterase 4 (PDE4) suppressed the inflammatory responses in the brain. However, the underlying mechanisms are poorly understood. Roflupram (ROF) is a novel PDE4 inhibitor. In the present study, we found that ROF enhanced the level of microtubule-associated protein 1 light chain 3 II (LC3-II) and decreased p62 in microglial BV-2 cells. Enhanced fluorescent signals were observed in BV-2 cells treated with ROF by Lysotracker red and acridine orange staining. In addition, immunofluorescence indicated a significant increase in punctate LC3. Moreover, β amyloid25-35 (Aβ25-35) or lipopolysaccharide (LPS) with ATP were used to activate inflammasome. We found that both LPS plus ATP and Aβ25-35 enhanced the conversion of pro-caspase-1 to cleaved-caspase-1 and increased the production of mature IL-1β in BV-2 cells. Interestingly, these effects were blocked by the treatment of ROF. Consistently, Knocking down the expression of PDE4B in primary microglial cells led to enhanced level of LC-3Ⅱ and decreased activation of inflammasome. What's more, Hoechst staining showed that ROF decreased the apoptosis of neuronal N2a cells in conditioned media from microglia. Our data also showed that ROF dose-dependently enhanced autophagy, reduced the activation of inflammasome and suppressed the production of IL-1β in mice injected with LPS. These effects were reversed by inhibition of microglial autophagy. These results put together demonstrate that ROF inhibits inflammasome activities and reduces the release of IL-1β by inducing autophagy. Therefore, ROF could be used as a potential therapeutic compound for the intervention of inflammation-associated diseases in the brain.