Ferroptosis in the Heart: Iron Calcium Crosstalk and Compartmentalization

摘要 在美国，大约每30秒就有一人死于心脏病。约150万 美国人每年都死于心肌梗塞。临床上，遗传性疾病(例如遗传性 血色沉着症)和重复输血(如镰状细胞性贫血和β地中海贫血所需) 已知会导致铁在心脏中积聚，铁超负荷心肌病是导致 死亡。最近有报道称，扩张型心肌病发生在高达95%的 Duchenne肌营养不良症和铁水平在小鼠模型中升高。此外，铁的水平是 已知在缺血后再灌流后心脏内升高。尽管如此，潜在的 铁相关心脏毒性的机制(S)尚不清楚。钙和铁都是已知的 在心脏中扮演着重要的细胞角色。细胞表现出对钙和钙的强烈调节的显著依赖 铁的浓度。任何一种离子的细胞调节失调都可导致收缩和舒张期功能障碍 最终导致心肌病。细胞内钙和/或细胞铁的正常动态平衡丧失或破坏 浓度不仅会导致直接的心肌毒性，而且还会导致心肌细胞的损失。 兴奋性和异常兴奋收缩偶联。我们认为钙和钙之间的串扰 铁结合在一起会导致高度心脏毒性的细胞环境。我们假设铁的存在会导致 通过一种被低估的途径导致细胞死亡，即心脏铁性下垂也会导致心肌病 作为缺血再灌注损伤。此外，我们提出了一种类似的联系，即心肌顿抑发生在 短暂的缺血再灌流部分是由于相同的串扰导致部分可逆的 心肌收缩功能减退。连接钙和铁运输信号的是线粒体 钙单转运体(MCU)和瞬时受体电位典型通道的激活。我们展示了那块铁 可调节TRPC离子通道功能。我们的初步数据表明，TRPC通道直接 被铁激活的。重要的是，TRPC的激活与钙反常损伤和后钙离子损伤有关。 心肌梗死重塑。我们的目标是证明钙和铁都不是简单的被动。 参与细胞过程，但当力量结合在一起时，会导致心脏的收缩和舒张期衰竭， 心脏毒性，以及两者共同预测人类寿命的缩短。我们将证明它是 用铁确定细胞死亡和心肌功能的细胞舒张期钙和线粒体钙 正在装车。我们假设MCU是线粒体铁超载的原因，并且相互作用(或 舒张期钙升高和线粒体铁增加之间的串扰)导致高度挥发性和 心脏毒性环境，通过铁性下垂导致心脏细胞死亡，从而导致心肌病和 缺血再灌注损伤。当涉及到心脏时，铁性下垂领域在许多方面都是新生的。 心脏铁性下垂的关键驱动因素和途径因生物环境而异。总而言之， 有大量可预见的机会来阐明触发因素(S)和激活的途径，从而 导致铁性下垂及其在各种形式的心肌病和缺血再灌注损伤中的作用。 我们的初步研究表明铁诱导的心肌病和Duchenne会出现铁性下垂。 肌肉营养不良症心肌病。我们将使用我们已经证明受到保护的土拨鼠 从缺血再灌注损伤中寻找新的抗铁下垂途径可作为靶向 治疗和/或预防性治疗。我们将追求以下目标。目标1：确定 铁中的MCU和TRPC在离体心肌细胞水平和体内均可引起心功能障碍。 子目标1-1：我们将在体外和体内证明MCU是否介导铁摄取和钙失调 与铁引起的心脏毒性有关。我们将确认线粒体铁的负载是由MCU介导的。这个 铁处理对有丝分裂功能、氧化应激的影响以及MCU的作用将被明确。次级目标1-2：我们 将展示铁诱导的TRPC的激活及其与体外(急性)心功能不全的关系 体内(Fe-CM)。次级目标1-3：从次级目标1-1和1-2获得的数据将用于填充计算机 E-C-M耦合模型和考虑了Fe效应的模拟运行。目标2：确定路径 参与I/R损伤时Fe-CM、DMD-CM和土拨鼠的铁性下垂。子目标2-1：我们将 确定通过MCU的丝裂原铁摄取是否在铁负荷的铁性下垂中起作用，并测试其他已知的 铁性下垂的诱因。我们将确定ROS和TRPC在体外和体内的作用，并与铁负载和 I/R子目标2-2：在DMD-CM心脏中，我们将确定铁下垂相关基因和蛋白质的重构， 评估生物标志物，并在体外测试对铁下垂诱导剂的敏感性。我们将测试各种铁性下垂。 通过抑制体内铁下垂来缓解DMD-CM的途径和尝试。子目标2-3：我们将获得小说 土拨鼠I/R保护机制研究(S)(体内外)。

Summary Approximately one person dies from heart disease every 30 seconds in the United States. About 1.5 million Americans die from myocardial infarction each year. Clinically, genetic disorders (e.g. hereditary hemochromatosis) and repeated blood transfusions (as required for sickle cell anemia and beta thalassemia) are known to cause Fe accumulation in the heart with iron overload cardiomyopathy being a major cause of death. It has been recently reported that dilated cardiomyopathy occurs in up to 95% of patients with Duchenne muscular dystrophy and that iron levels are elevated in mouse models. Furthermore, iron levels are known to be elevated in the heart after ischemia followed by reperfusion. Nevertheless, the underlying mechanism(s) involved in Fe associated cardiotoxicity remain unclear. Calcium and iron are both known to play vital cellular roles in the heart. Cells exhibit a remarkable dependence on keen regulation of calcium and iron concentrations. Cellular dysregulation of either ion can result in systolic and diastolic dysfunction and ultimately cardiomyopathy. Loss or disruption of normal homeostasis of cellular calcium and/or cellular iron concentrations can not only cause direct myocardial cardiotoxicity, but can also result in loss of myocardial excitability and abnormal excitation contraction coupling. We propose that a cross talk between calcium and iron combined results in a highly cardiotoxic cellular environment. We posit that the presence of iron can result in cell death via an underappreciated pathway, i.e. ferroptosis in the heart resulting in cardiomyopathy as well as ischemia reperfusion injury. Furthermore, we propose a similar link between myocardial stunning seen after brief periods of ischemia reperfusion to be in part due to the same cross talk resulting in a partially reversible reduction in myocardial systolic function. Linking the transport of calcium and iron signaling is the mitochondria Ca uniporter (mCU) and the activation of transient receptor potential canonical channels. We show that iron can regulate TRPC ion channel function. Our preliminary data have shown that TRPC channels are directly activated by iron. Importantly, activation of TRPCs has been implicated in calcium paradox injury and post- myocardial infarction remodeling. We aim to demonstrate that neither calcium nor iron are simply passive participants in cellular processes, but when forces are joined result in systolic and diastolic failure of the heart, cardiotoxcity, and together are predictive of a reduced lifespan in humans. We will demonstrate that it is cellular diastolic calcium and mitochondrial calcium that defines cell death and myocardial function with iron loading. We hypothesize that mCU accounts for mitochondrial iron overload and that an interaction (or crosstalk) between elevated diastolic calcium and increased mitochondrial iron results in a highly volatile and cardiotoxic environment that causes cardiac cell death via ferroptosis resulting in cardiomyopathy and ischemia reperfusion injury. The field of ferroptosis is nascent in many regards when it comes to the heart. The key drivers and pathways of ferroptosis in the heart differ depending on biological context. In summary, there is a wealth of foreseeable opportunities to elucidate both the trigger(s) and pathways activated that can result in ferroptosis and its role in various forms of cardiac cardiomyopathy and ischemia-reperfusion injury. Our preliminary studies have demonstrated ferroptosis in iron induced cardiomyopathy and Duchenne Muscular Dystrophy cardiomyopathy. We will use woodchucks that have been shown by us to be protected from ischemia reperfusion injury as a tool to identify novel anti-ferroptosis pathways that can be targeted for treatment and/or preventative therapies. We will pursue the following aims. Aim 1: Determine the role of mCU and TRPCs in Fe induced cardiac dysfunction at the level of the isolated myocyte and in vivo. Sub-aim 1-1: We will demonstrate in vitro and in vivo whether mCU mediated Fe uptake and Ca dysregulation are associated with Fe induced cardiac toxicity. We will confirm mito Fe loading is mediated by mCU. The effects of Fe treatment on mito function, oxidative stress and the role of mCU will be defined. Sub-aim 1-2: We will demonstrate Fe induced activation of TRPCs and the relationship to cardiac dysfunction in vitro (acute) and in vivo (Fe-CM). Sub-aim 1-3: Data derived from Sub-aims 1-1 and 1-2 will be used to populate a computer model of E-C-M coupling and simulations run with incorporation of Fe effects. Aim 2: To determine pathways involved in ferroptosis in Fe-CM, DMD-CM, and Woodchucks during I/R injury. Sub-aim 2-1: We will determine whether mito Fe uptake via mCU plays a role in ferroptosis with Fe loading and test other known inducers of ferroptosis. We will determine the role of ROS and TRPC in vitro and in vivo with Fe loading and I/R. Sub-aim 2-2: In DMD-CM hearts, we will determine remodeling of ferroptosis-related genes and proteins, evaluate biomarkers, and test the susceptibility to ferroptosis inducers in vitro. We will test various ferroptosis pathways and attempt to mitigate DMD-CM by inhibiting ferroptosis in vivo. Sub-aim 2-3: We will obtain novel insights into protective mechanism(s) in woodchucks during I/R (in vitro and in vivo).