Karwi Qutuba G, Bornbaum Julia, Boengler Kerstin, Torregrossa Roberta, Whiteman Matthew, Wood Mark E, Schulz Rainer, Baxter Gary F
School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK.
College of Medicine, University of Diyala, Diyala, Iraq.
Br J Pharmacol. 2017 Feb;174(4):287-301. doi: 10.1111/bph.13688. Epub 2017 Jan 24.
H S protects myocardium against ischaemia/reperfusion injury. This protection may involve the cytosolic reperfusion injury salvage kinase (RISK) pathway, but direct effects on mitochondrial function are possible. Here, we investigated the potential cardioprotective effect of a mitochondria-specific H S donor, AP39, at reperfusion against ischaemia/reperfusion injury.
Anaesthetized rats underwent myocardial ischaemia (30 min)/reperfusion (120 min) with randomization to receive interventions before reperfusion: vehicle, AP39 (0.01, 0.1, 1 μmol·kg ), or control compounds AP219 and ADT-OH (1 μmol·kg ). LY294002, L-NAME or ODQ were used to investigate the involvement of the RISK pathway. Myocardial samples harvested 5 min after reperfusion were analysed for RISK protein phosphorylation and isolated cardiac mitochondria were used to examine the direct mitochondrial effects of AP39.
AP39, dose-dependently, reduced infarct size. Inhibition of either PI3K/Akt, eNOS or sGC did not affect this effect of AP39. Western blot analysis confirmed that AP39 did not induce phosphorylation of Akt, eNOS, GSK-3β or ERK1/2. In isolated subsarcolemmal and interfibrillar mitochondria, AP39 significantly attenuated mitochondrial ROS generation without affecting respiratory complexes I or II. Furthermore, AP39 inhibited mitochondrial permeability transition pore (PTP) opening and co-incubation of mitochondria with AP39 and cyclosporine A induced an additive inhibitory effect on the PTP.
AP39 protects against reperfusion injury independently of the cytosolic RISK pathway. This cardioprotective effect could be mediated by inhibiting PTP via a cyclophilin D-independent mechanism. Thus, selective delivery of H S to mitochondria may be therapeutically applicable for employing the cardioprotective utility of H S.
硫化氢可保护心肌免受缺血/再灌注损伤。这种保护作用可能涉及胞质再灌注损伤挽救激酶（RISK）途径，但也可能直接影响线粒体功能。在此，我们研究了线粒体特异性硫化氢供体AP39在再灌注时对缺血/再灌注损伤的潜在心脏保护作用。
对麻醉大鼠进行心肌缺血（30分钟）/再灌注（120分钟），随机分组，在再灌注前接受干预：溶剂、AP39（0.01、0.1、1μmol·kg）或对照化合物AP219和ADT-OH（1μmol·kg）。使用LY294002、L-NAME或ODQ研究RISK途径的参与情况。再灌注5分钟后采集心肌样本，分析RISK蛋白磷酸化情况，并使用分离的心脏线粒体检测AP39对线粒体的直接作用。
AP39剂量依赖性地减小梗死面积。抑制PI3K/Akt、eNOS或sGC均不影响AP39的这一作用。蛋白质印迹分析证实，AP39不会诱导Akt、eNOS、GSK-3β或ERK1/2的磷酸化。在分离的肌膜下和肌原纤维间线粒体中，AP39显著减弱线粒体活性氧生成，而不影响呼吸复合体I或II。此外，AP39抑制线粒体通透性转换孔（PTP）开放，线粒体与AP39和环孢素A共同孵育对PTP产生相加抑制作用。
AP39独立于胞质RISK途径发挥抗再灌注损伤作用。这种心脏保护作用可能通过不依赖亲环素D的机制抑制PTP介导。因此，将硫化氢选择性递送至线粒体在治疗上可能适用于发挥硫化氢的心脏保护作用。
