The Contribution of Melanocyte-like Cells to Atrial Function and Development

黑素细胞样细胞对心房功能和发育的贡献

• 批准号: 8675915
• 负责人: VICKAS V PATEL
• 金额: $ 15.9万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8675915
• 关键词: Action Potentials; Adrenergic Receptor; Affect; Anatomy; Animal Model; Arrhythmia; Atrial Fibrillation; Atrial Function; Biological; Biology; Calcium; Carbachol; Cardiac; Cell Lineage; Cells; Characteristics; Clinical; Coupling; Data; Dermal; Development; Disease; Dopachrome isomerase; Elderly; Electrophysiology (science); Engineering; Enzymes; Exhibits; Gap Junctions; Gated Ion Channel; Gene Expression Profile; Generations; Genes; Genetic; Genetic Transcription; Genetically Engineered Mouse; Goals; Heart; Heart Atrium; Heterozygote; Human; In Vitro; Investigation; Ions; Knockout Mice; Knowledge; Laboratories; Lead; Manganese Superoxide Dismutase; Maps; Modeling; Monophenol Monooxygenase; Mus; Muscarinic Acetylcholine Receptor; Muscarinic Agonists; Muscle Cells; Mutant Strains Mice; Myocardium; Optics; Oxidants; Patch-Clamp Techniques; Pathogenesis; Pathologic; Pattern; Physiological; Physiology; Play; Population; Predisposition; Property; Proto-Oncogene Protein c-kit; Publishing; Pulmonary veins; Reactive Oxygen Species; Research Personnel; Role; Series; Site; Sodium-Calcium Exchanger; Staging; Stimulus; Stress; Techniques; Testing; Wild Type Mouse; Work; base; design; heart rhythm; improved; in vivo; insight; melanocyte; mouse model; novel; oxidative damage; receptor; research study; response; voltage

DESCRIPTION (provided by applicant): We recently described a novel population of melanocyte-like cells in the pulmonary veins and atria of humans and mice. In the developing and mature heart, melanocyte-like cells are found in a pattern unlike that of any currently known cell lineage and are found in anatomic regions that often give rise to clinical atrial arrhythmia triggers. These cells express a unique transcription signature that is distinct from that of atrial myocytes or dermal melanocytes. Interestingly, isolated murine melanocyte-like cells are electrically excitable and generate atrial myocyte-like action potentials. We have found that genetic deletion of the enzyme dopachrome tautomerase (Dct), which is expressed by both human and murine cardiac melanocytes, unmasks a pathological state with action potential prolongation and afterdepolarizations in these cells. Furthermore, mature Dct knockout mice retain melanocyte-like cells and have structurally normal hearts, yet display increased susceptibility to atrial arrhythmias. While wild-type mice with melanocyte-like cells in their hearts do not have increased atrial arrhythmias at baseline, they do have more atrial arrhythmias when challenged with the muscarinic agonist carbachol compared to c-kit mutant mice that lack melanocyte-like cells in their hearts. In addition, Dct knockout mice have fewer atrial arrhythmias when treated with reactive oxygen species scavengers. Hence, melanocyte-like cells may contribute to atrial arrhythmias in response to increased stresses (i.e. autonomic stimulation or reactive oxygen species) that commonly induce clinical atrial arrhythmias. Despite our initial characterization, the function of melanocyte-like cells during normal physiologic and pathophysiologic states remains obscure. Furthermore, while we have some evidence melanocyte-like cells are excitable and may influence arrhythmogenesis; the underlying electrophysiologic characteristics of these cells require further investigation to understand their potential contribution to arrhythmias. Therefore, we are proposing a series of in vitro and in vivo experiments using genetically engineered mouse models to characterize the cellular electrophysiology of these cells and determine their contribution to atrial arrhythmias. The specific aims proposed include: 1) elucidating the voltage-dependent currents underlying the electrical excitability of isolated murine melanocyte-like cells and the direct contribution of melanocyte-like to atrial arrhythmia triggers, 2) determining the effects of autonomic stimulation upon Dct-positive melanocyte-like cellular excitability and their contribution atrial arrhythmias, 3) assessing the effects of reactive oxygen species upon the excitability of Dct-positive melanocyte-like cells and their influence upon atrial arrhythmias, and 4) investigating the role of melanocyte-like cells in the normal heart. The knowledge we will gain about the basic biology of melanocyte-like cells is likely to open new avenues in our understanding of atrial electrophysiology, with the potential for paradigm shifting insights into the pathogenesis of atrial arrhythmias.

描述（由申请人提供）：我们最近描述了人类和小鼠肺静脉和心房中的一种新的黑素细胞样细胞群。在发育和成熟的心脏中，黑素细胞样细胞的模式与目前已知的任何细胞谱系不同，并且存在于经常引起临床房性心律失常触发因素的解剖区域中。这些细胞表达与心房肌细胞或真皮黑素细胞不同的独特转录特征。有趣的是，分离的小鼠黑素细胞样细胞具有电兴奋性并产生心房肌细胞样动作电位。我们发现，人类和小鼠心脏黑素细胞表达的多巴色素互变异构酶（Dct）的基因缺失，揭示了这些细胞中动作电位延长和后去极化的病理状态。此外，成熟的 Dct 敲除小鼠保留了黑色素细胞样细胞，心脏结构正常，但对房性心律失常的易感性增加。虽然心脏中含有黑素细胞样细胞的野生型小鼠在基线时房性心律失常并未增加，但与心脏中缺乏黑素细胞样细胞的 c-kit 突变小鼠相比，当用毒蕈碱激动剂卡巴胆碱攻击时，它们确实会出现更多的房性心律失常。此外，当用活性氧清除剂治疗时，Dct 基因敲除小鼠的房性心律失常较少。因此，黑素细胞样细胞可能会响应增加的压力（即自主神经刺激或活性氧）而导致房性心律失常，而压力增加通常会诱发临床房性心律失常。尽管我们最初进行了表征，但正常生理和病理生理状态下黑素细胞样细胞的功能仍然不清楚。此外，虽然我们有一些证据表明黑素细胞样细胞具有兴奋性并可能影响心律失常的发生；这些细胞的潜在电生理特征需要进一步研究，以了解它们对心律失常的潜在贡献。因此，我们提出使用基因工程小鼠模型进行一系列体外和体内实验，以表征这些细胞的细胞电生理学并确定它们对房性心律失常的贡献。提出的具体目标包括：1) 阐明分离的小鼠黑素细胞样细胞电兴奋性背后的电压依赖性电流以及黑素细胞样细胞对房性心律失常触发的直接贡献，2) 确定自主神经刺激对 Dct 阳性黑素细胞样细胞兴奋性及其对房性心律失常的贡献的影响，3) 评估活性氧对 Dct 阳性黑素细胞样细胞兴奋性的影响及其对房性心律失常的影响，4) 研究黑素细胞样细胞在正常心脏中的作用。我们将获得的关于黑素细胞样细胞的基本生物学知识可能会为我们理解心房电生理学开辟新的途径，并有可能改变对房性心律失常发病机制的认识。