Transthyretin deposition alters cardiomyocyte sarcomeric architecture, calcium transients, and contractile force.
Transthyretin deposition alters cardiomyocyte sarcomeric architecture, calcium transients, and contractile force.
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DOI：
10.14814/phy2.15207
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发表时间：
2022-03
影响因子：
2.5
通讯作者：
Russell B
中科院分区：
文献类型：
--
作者：
Dittloff KT;Spanghero E;Solís C;Banach K;Russell B
年龄相关性野生型甲状腺素运载蛋白淀粉样变性（wtATTR）的特征是错误折叠的甲状腺素运载蛋白（TTR）的淀粉样原纤维在许多器官的结缔组织中的全身性沉积。在心脏中，这导致年龄相关性心力衰竭伴射血分数保留（HFpEF）。检验的假设是，体外沉积的TTR破坏心肌细胞-细胞和细胞-基质粘附复合物，导致钙处理、力产生和肌节解体改变。人iPSC衍生的心肌细胞和新生大鼠心室肌细胞（NRVM）在模拟健康人心肌硬度（10 kPa）的TTR包被的聚合物基质上生长时，收缩和舒张速度降低，并且使用牵引力显微镜测量的力产生降低。在TTR原纤维包被的基质上培养时，NRVM和成年小鼠心房心肌细胞的钙动力学均发生改变，瞬变时间延长。此外，如加载了差距连接可渗透染料钙黄绿素-AM的细胞的FRAP动力学所示，在涂覆有TTR原纤维的刚性（~GPa）、平坦或微槽基底上生长的NRVM表现出显著降低的细胞间电耦合，沿着具有降低的间隙连接含量，如通过定量连接蛋白43染色所确定的。在各种TTR原纤维包被基质上的NRVM中观察到显著的肌节紊乱和肌节含量损失，以及肌节泛素定位增加。TTR的存在减少了细胞间的机械连接，如通过N-钙粘蛋白和黏着斑蛋白的定量免疫荧光染色所证明的。目前wtATTR的治疗成本高昂，只能减缓疾病进展;因此，更好地了解TTR淀粉样蛋白诱导的心肌细胞适应不良可能会发现新的治疗靶点。甲状腺素运载蛋白（TTR）在心脏中的纤维沉积是老年人射血分数保留的心功能不全和衰竭（HFpEF）的常见原因。研究表明，TTR原纤维改变主要心肌细胞功能，收缩和舒张速度降低，减少力的产生，延长钙瞬变，并减少细胞间的电耦合。在结构上，TTR引起肌节解体，减少机电连接，并增加肌节泛素定位。这些发现可能为心脏淀粉样变性提供新的治疗方法。
Age‐related wild‐type transthyretin amyloidosis (wtATTR) is characterized by systemic deposition of amyloidogenic fibrils of misfolded transthyretin (TTR) in the connective tissue of many organs. In the heart, this leads to age‐related heart failure with preserved ejection fraction (HFpEF). The hypothesis tested is that TTR deposited in vitro disrupts cardiac myocyte cell‐to‐cell and cell‐to‐matrix adhesion complexes, resulting in altered calcium handling, force generation, and sarcomeric disorganization. Human iPSC‐derived cardiomyocytes and neonatal rat ventricular myocytes (NRVMs), when grown on TTR‐coated polymeric substrata mimicking the stiffness of the healthy human myocardium (10 kPa), had decreased contraction and relaxation velocities as well as decreased force production measured using traction force microscopy. Both NRVMs and adult mouse atrial cardiomyocytes had altered calcium kinetics with prolonged transients when cultured on TTR fibril‐coated substrates. Furthermore, NRVMs grown on stiff (~GPa), flat or microgrooved substrates coated with TTR fibrils exhibited significantly decreased intercellular electrical coupling as shown by FRAP dynamics of cells loaded with the gap junction‐permeable dye calcein‐AM, along with decreased gap junction content as determined by quantitative connexin 43 staining. Significant sarcomeric disorganization and loss of sarcomere content, with increased ubiquitin localization to the sarcomere, were seen in NRVMs on various TTR fibril‐coated substrata. TTR presence decreased intercellular mechanical junctions as evidenced by quantitative immunofluorescence staining of N‐cadherin and vinculin. Current therapies for wtATTR are cost‐prohibitive and only slow the disease progression; therefore, better understanding of cardiomyocyte maladaptation induced by TTR amyloid may identify novel therapeutic targets. Transthyretin (TTR) fibril deposition in the heart is a common cause of cardiac dysfunction and failure with preserved ejection fraction (HFpEF) in the elderly. Studies show that TTR fibrils alter primary cardiac myocyte function with decreased contraction and relaxation velocities, reduced force production, prolonged calcium transients, and decreased intercellular electrical coupling. Structurally, the TTR caused sarcomere disorganization, reduced electromechanical junctions, and increased sarcomeric ubiquitin localization. These findings may suggest new therapeutic approaches for cardiac amyloidosis.
DOI：
10.1007/s00392-020-01801-y
发表时间：
2021-04
期刊：
Clinical research in cardiology : official journal of the German Cardiac Society
影响因子：
--
作者：
Hein S;Furkel J;Knoll M;Aus dem Siepen F;Schönland S;Hegenbart U;Katus HA;Kristen AV;Konstandin MH
通讯作者：
Konstandin MH