Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Carlos Chagas Filho Institute of Biophysics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Alberto Luis Coimbra Institute of Post-Graduate Studies and Research in Engineering, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Pulm Pharmacol Ther. 2018 Jun;50:100-110. doi: 10.1016/j.pupt.2018.04.008. Epub 2018 Apr 24.
This study assessed pulmonary outcomes generated by inhibiting key enzymes of sphingolipid metabolism pathways related to ceramide synthesis in a murine model of lung injury induced by lipopolysaccharide (LPS).
C57BL/6 male adult mice received LPS intratracheally and the expressions of acid sphingomyelinase (ASM), neutral sphingomyelinase (NSM), serine palmitoyl transferase (SPT) and dihydroceramide synthase (DS) were assessed at 2, 4, 6, 12 and 24 h after LPS instillation in lung homogenate (n = 30). The pharmacological inhibition of ASM, NSM, SPT and DS were assayed in other mice groups by three different doses of desipramine, GW4869, myriocin and fumonisin, respectively (n = 90). Their most effective doses were administered intraperitoneally 1 or 2 h before LPS to different animal groups (n = 120). Mice underwent determination of pulmonary mechanics, lung histopathological aspects and apoptosis.
The expression levels of the enzymes reached their peak at 2-4 h after LPS administration. ASM inhibition attenuated alveolar collapse and GW4869 decreased lung elastance, proinflammatory cytokines' levels and was more effective to improve alveolar collapse than desipramine. On the other hand, SPT blockage aggravated lung lesion and no effects it was observed with fumonisin. Moreover, simultaneous administration of inhibitors (desipramine + GW4869, myriocin + fumonisin and all inhibitors together) resulted in no changes.
Blockage of sphingomyelinases and the de novo pathways improved and aggravated lung injury, respectively, putatively suggesting specific targets to therapeutic strategies in LPS-induced lung injury.
本研究评估了抑制与脂多糖（LPS）诱导的肺损伤相关的神经酰胺合成相关鞘脂代谢途径的关键酶对肺的影响。
雄性 C57BL/6 成年小鼠通过气管内给予 LPS，并在 LPS 给药后 2、4、6、12 和 24 小时评估肺匀浆中酸性鞘磷脂酶（ASM）、中性鞘磷脂酶（NSM）、丝氨酸棕榈酰转移酶（SPT）和二氢神经酰胺合酶（DS）的表达（n=30）。通过三种不同剂量的去甲丙咪嗪、GW4869、米诺环素和伏马菌素分别在其他小鼠组中测定 ASM、NSM、SPT 和 DS 的药理抑制作用（n=90）。它们的最有效剂量在 LPS 前 1 或 2 小时经腹腔给药至不同的动物组（n=120）。对小鼠进行肺力学、肺组织病理学和细胞凋亡测定。
酶的表达水平在 LPS 给药后 2-4 小时达到峰值。ASM 抑制减弱了肺泡塌陷，GW4869 降低了肺弹性，降低了促炎细胞因子的水平，并且比去甲丙咪嗪更有效地改善肺泡塌陷。另一方面，SPT 阻断加重了肺损伤，而伏马菌素则没有效果。此外，同时给予抑制剂（去甲丙咪嗪+GW4869、米诺环素+伏马菌素和所有抑制剂一起）没有变化。
鞘磷脂酶和从头途径的阻断分别改善和加重 LPS 诱导的肺损伤，这提示针对 LPS 诱导的肺损伤的治疗策略有特定的靶点。
