Data from Casin et al "<b>Loss of cyclophilin D prolyl isomerase activity desensitizes mitochondrial permeability transition pore opening in isolated cardiac mitochondria, but does not protect in myocardial ischemia-reperfusion injury</b>"

To define the role of CyPD prolyl isomerase activity in regulating PTP and necrotic cell death, we used CRISPR/Cas 9 to generate novel homozygous germline knock-in mice with a prolyl isomerase-dead CyPD R96G mutation in all cells (CyPD^R96G). Our data suggest prolyl isomerase activity is required for Ca²⁺-activated PTP in isolated mitochondria. Loss of isomerase activity does not protect against I/R injury whereas CyPD deletion protects, implying that isomerase dead CyPD can activate I/R-mediated death. However, altered metabolism in CyPD knockout mice could play a role [7]. These data would be consistent with the hypothesis suggesting two PTPs. We propose that PTP1 activation by CyPD requires isomerase activity and is the main PTP activity measured in isolated mitochondria with Ca²⁺ overload, whereas PTP2, which we hypothesize is primarily responsible for cell death in I/R, is potentiated by mutant CyPD lacking isomerase activity. If correct, this hypothesis would suggest that studies of PTP in isolated mitochondria may not translate to protection in I/R.

为明确亲环素D（Cyclophilin D, CyPD）的脯氨酰异构酶活性在调控线粒体通透性转换孔（permeability transition pore, PTP）与坏死性细胞死亡中的作用，我们借助CRISPR/Cas9技术构建了全新的纯合生殖系敲入小鼠模型，该模型所有体细胞均携带脯氨酰异构酶失活的CyPD R96G突变（以下记为CyPD^R96G）。我们的实验数据显示，脯氨酰异构酶活性是离体线粒体中Ca²⁺激活的PTP形成所必需的条件。异构酶活性缺失无法对抗缺血再灌注（ischemia/reperfusion, I/R）损伤，而CyPD基因敲除却可产生保护效应，这提示失活型CyPD仍可介导I/R相关的细胞死亡。不过，CyPD敲除小鼠的代谢异常或许也参与了该过程[7]。上述实验数据与“存在两种PTP亚型”的假说相一致。我们提出如下假说：CyPD介导的PTP1激活依赖于脯氨酰异构酶活性，这也是Ca²⁺过载条件下离体线粒体中测得的主要PTP活性；而我们推测主要负责I/R损伤中细胞死亡的PTP2，则可被缺失异构酶活性的突变型CyPD所增强。若该假说成立，则意味着离体线粒体中关于PTP的研究结论或许无法直接外推至I/R损伤的保护效应研究中。

搜集汇总

背景与挑战

背景概述

该数据集来自一项心脏线粒体研究，通过CRISPR/Cas9技术生成CyPDR96G突变小鼠模型，探讨环孢素D脯氨酰异构酶活性对线粒体通透性转换孔（PTP）的调控作用及其在心肌缺血再灌注损伤中的影响。研究发现，脯氨酰异构酶活性是钙激活PTP所必需的，但缺失该活性不能提供心肌保护，而CyPD缺失则具有保护效应，提示可能存在两种不同的PTP机制。数据集包含原始实验数据，发布于2023年，文件大小为194.05 MB，属于公共领域，适用于细胞生物学和系统生物学领域的研究。