Medical Science Department, Daiichi Sankyo Co., Ltd., Tokyo, Japan.
Manufacturing Department III, Kitasato Daiichi Sankyo Vaccine Co., Ltd., Saitama, Japan.
Sci Rep. 2017 Jun 20;7(1):3864. doi: 10.1038/s41598-017-03651-7.
Mitochondria are involved in a variety of physiological and pathological processes. Ca uptake is one of the important functions of the organelle for maintenance of cellular Ca homeostasis. In pathological conditions such as ischemia reperfusion injury, Ca overload into mitochondria induces mitochondrial permeability transition (MPT), a critical step for cell death. Because inhibition of MPT is a promising approach to protecting cells and organs, it is important for drug discovery to identify novel chemicals or mechanisms to inhibit MPT. Here we report upon a small-molecule compound DS44170716 that inhibits Ca-induced MPT in rat liver isolated mitochondria. DS44170716 protects human liver HepG2 cells from Ca-induced death with a level of protection similar to cyclosporin A (CsA). The inhibitory mechanism of DS44170716 against MPT is independent on PPIF, a target of CsA. DS44170716 blocks Ca flux into the mitochondria by decreasing mitochondrial membrane potential, while potently inhibiting mitochondrial complex III activities and weakly inhibiting complex IV and V activities. Similarly, complex III inhibitor antimycin A, complex IV inhibitor KCN or complex V inhibitor oligomycin inhibits Ca uptake of isolated mitochondria. These results show that DS44170716 is a novel class inhibitor of MPT by blocking of mitochondrial complexes and Ca-overload into mitochondria.
线粒体参与多种生理和病理过程。钙摄取是细胞器维持细胞钙稳态的重要功能之一。在缺血再灌注损伤等病理条件下，钙超载进入线粒体诱导线粒体通透性转换（MPT），这是细胞死亡的关键步骤。由于抑制 MPT 是保护细胞和器官的一种有前途的方法，因此，确定抑制 MPT 的新型化学物质或机制对于药物发现非常重要。在这里，我们报告了一种小分子化合物 DS44170716，它可以抑制大鼠肝分离线粒体中钙诱导的 MPT。DS44170716 可保护人肝癌 HepG2 细胞免受钙诱导的死亡，其保护水平与环孢素 A（CsA）相似。DS44170716 对 MPT 的抑制机制不依赖于 CsA 的靶点 PPIF。DS44170716 通过降低线粒体膜电位来阻止钙流入线粒体，同时强烈抑制线粒体复合物 III 活性，弱抑制复合物 IV 和 V 活性。同样，复合物 III 抑制剂antimycin A、复合物 IV 抑制剂 KCN 或复合物 V 抑制剂寡霉素抑制分离线粒体的钙摄取。这些结果表明，DS44170716 通过阻断线粒体复合物和钙超载进入线粒体，是一种新型的 MPT 抑制剂。
