University of Louisville Alcohol Research Center, University of Louisville School of Medicine, Louisville, KY, USA; Department of Internal Medicine, University of Louisville School of Medicine, Louisville, KY, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA.
Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, USA; Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, KY, USA.
Neuropharmacology. 2017 Oct;125:376-385. doi: 10.1016/j.neuropharm.2017.08.011. Epub 2017 Aug 12.
It is increasingly evident that alcohol-induced, gut-mediated peripheral endotoxemia plays a significant role in glial cell activation and neuro-inflammation. Using a mouse model of chronic alcohol feeding, we examined the causal role of endotoxin- and cytokine-responsive Pde4 subfamily b (Pde4b) expression in alcohol-induced neuro-inflammation. Both pharmacologic and genetic approaches were used to determine the regulatory role of Pde4b. In C57Bl/6 wild type (WT) alcohol fed (WT-AF) animals, alcohol significantly induced peripheral endotoxemia and Pde4b expression in brain tissue, accompanied by a decrease in cAMP levels. Further, along with Pde4b, there was a robust activation of astrocytes and microglia accompanied by significant increases in the inflammatory cytokines (Tnfα, Il-1β, Mcp-1 and Il-17) and the generalized inflammatory marker Cox-2. At the cellular level, alcohol and inflammatory mediators, particularly LPS, Tnfα and Hmgb1 significantly activated microglial cells (Iba-1 expression) and selectively induced Pde4b expression with a minimal to no change in Pde4a and d isoforms. In comparison, the alcohol-induced decrease in brain cAMP levels was completely inhibited in WT mice treated with the Pde4 specific pharmacologic inhibitor rolipram and in Pde4b-/- mice. Moreover, all the observed markers of alcohol-induced brain inflammation were markedly attenuated. Importantly, glial cell activation induced by systemic endotoxemia (LPS administration) was also markedly decreased in Pde4b-/- mice. Taken together, these findings strongly support the notion that Pde4b plays a critical role in coordinating alcohol-induced, peripheral endotoxemia mediated neuro-inflammation and could serve as a significant therapeutic target.
越来越多的证据表明,酒精诱导的肠道外周内毒素血症在神经胶质细胞激活和神经炎症中起着重要作用。我们使用慢性酒精喂养的小鼠模型,研究了内毒素和细胞因子反应性 Pde4 亚家族 b (Pde4b) 表达在酒精诱导的神经炎症中的因果作用。我们使用药理学和遗传学方法来确定 Pde4b 的调节作用。在 C57Bl/6 野生型(WT)酒精喂养(WT-AF)动物中,酒精显著诱导外周内毒素血症和脑组织中 Pde4b 的表达,同时 cAMP 水平降低。此外,随着 Pde4b 的表达,星形胶质细胞和小胶质细胞被强烈激活,同时炎症细胞因子(Tnfα、Il-1β、Mcp-1 和 Il-17)和普遍的炎症标志物 Cox-2 显著增加。在细胞水平上,酒精和炎症介质,特别是 LPS、Tnfα 和 Hmgb1,显著激活小胶质细胞(Iba-1 表达),并选择性诱导 Pde4b 表达,而 Pde4a 和 d 同工型的变化最小或没有变化。相比之下,在用 PDE4 特异性药理学抑制剂罗利普兰处理的 WT 小鼠和 Pde4b-/- 小鼠中,完全抑制了酒精诱导的大脑 cAMP 水平下降。此外,所有观察到的酒精诱导的大脑炎症标志物均显著减弱。重要的是,Pde4b-/- 小鼠中全身内毒素血症(LPS 给药)诱导的神经胶质细胞激活也明显减少。总之,这些发现强烈支持 Pde4b 在协调酒精诱导的外周内毒素血症介导的神经炎症中起着关键作用的观点,并可能成为一个重要的治疗靶点。