School of Human Sciences, University of Western Australia, Crawley, WA, Australia; Victor Chang Cardiac Research Institute, Sydney, NSW, Australia.
J Mol Cell Cardiol. 2022 Nov;172:100-108. doi: 10.1016/j.yjmcc.2022.08.001. Epub 2022 Aug 27.
Cardiovascular disease continues to be the leading health burden worldwide and with the rising rates in obesity and type II diabetes and ongoing effects of long COVID, it is anticipated that the burden of cardiovascular morbidity and mortality will increase. Calcium is essential to cardiac excitation and contraction. The main route for Ca influx is the L-type Ca channel (Ca1.2) and embryos that are homozygous null for the Ca1.2 gene are lethal at day 14 postcoitum. Acute changes in Ca influx through the channel contribute to arrhythmia and sudden death, and chronic increases in intracellular Ca contribute to pathological hypertrophy and heart failure. We use a multidisciplinary approach to study the regulation of the channel from the molecular level through to in vivo CRISPR mutant animal models. Here we describe some examples of our work from over 2 decades studying the role of the channel under physiological and pathological conditions. Our single channel analysis of purified human Ca1.2 protein in proteoliposomes has contributed to understanding direct molecular regulation of the channel including identifying the critical serine involved in the "fight or flight" response. Using the same approach we identified the cysteine responsible for altered function during oxidative stress. Chronic activation of the L-type Ca channel during oxidative stress occurs as a result of persistent glutathionylation of the channel that contributes to the development of hypertrophy. We describe for the first time that activation of the channel alters mitochondrial function (and energetics) on a beat-to-beat basis via movement of cytoskeletal proteins. In translational studies we have used this response to "report" mitochondrial function in models of cardiomyopathy and to test efficacy of novel therapies to prevent cardiomyopathy.
心血管疾病仍然是全球主要的健康负担，随着肥胖和 2 型糖尿病发病率的上升以及长期 COVID 的持续影响，预计心血管发病率和死亡率的负担将会增加。钙对心脏兴奋和收缩至关重要。钙内流的主要途径是 L 型钙通道（Ca1.2），而 Ca1.2 基因纯合缺失的胚胎在受精后第 14 天死亡。通过通道的钙内流的急性变化导致心律失常和猝死，而细胞内钙的慢性增加导致病理性肥大和心力衰竭。我们采用多学科方法从分子水平到体内 CRISPR 突变动物模型来研究通道的调节。在这里，我们描述了我们在 20 多年的时间里研究通道在生理和病理条件下的作用的一些例子。我们在质体中对纯化的人类 Ca1.2 蛋白进行的单通道分析有助于理解通道的直接分子调节，包括确定参与“战斗或逃跑”反应的关键丝氨酸。使用相同的方法，我们确定了在氧化应激期间导致功能改变的半胱氨酸。氧化应激期间 L 型钙通道的慢性激活是由于通道的持续谷胱甘肽化引起的，这导致了肥大的发展。我们首次描述了通道的激活通过细胞骨架蛋白的运动，在逐个跳动的基础上改变线粒体功能（和能量学）。在转化研究中，我们利用这种反应来“报告”心肌病模型中的线粒体功能，并测试预防心肌病的新型治疗方法的疗效。
