Augmentation of Cav1 channel current and action potential duration after uptake of S100A1 in sympathetic ganglion neurons
Augmentation of Cav1 channel current and action potential duration after uptake of S100A1 in sympathetic ganglion neurons
复制标题
DOI：
10.1152/ajpcell.00140.2009
复制
发表时间：
2009-10-01
影响因子：
5.5
通讯作者：
Schneider, Martin F.
中科院分区：
文献类型：
--
作者：
Hernandez-Ochoa, Erick O.;Prosser, Benjamin L.;Schneider, Martin F.
Hernanal-Ochoa EO，Prosser BL，Wright NT，Contreras M，Weber DJ，Schneider MF.交感神经节神经元摄取S100 A1后Cav 1通道电流和动作电位时程增加美国生理学杂志细胞生理学297：C955-C970，2009年。首次发表于2009年8月5日; doi：10.1152/ajpcell.00140.2009。S100 A1是EF-手型的21-kDa二聚体Ca 2+结合蛋白，在心肌细胞中表达，是心脏功能的重要调节剂。在缺血期间，心肌细胞分泌S100 A1至细胞外间隙。虽然细胞外S100 A1的作用已经在心肌细胞中被记录，但尚不清楚S100 A1是否对邻近心脏细胞的其他组织发挥调节作用。因此，我们试图研究外源性S100 A1对上级颈神经节（SCG）神经元钙信号和电特性的影响。免疫组化和Western blot结果显示，SCG神经元中无内源性S100 A1。S100 A1存在于细胞外培养基中时，培养的SCG神经元摄取S100 A1。在细胞内，外源性S100 A1定位在整个细胞质中的点状图案，但被排除在细胞核之外。S100 A1与受体和非受体介导的内吞标记物部分共定位，表明在SCG神经元中，S100 A1内化涉及多种内吞途径。在区室化的SCG培养物中，轴突投射能够向神经元胞体摄取和运输S100 A1。外源性S100 A1以PKA依赖的方式应用于细胞外或细胞内增强Ca（v）1通道电流，延长动作电位，并放大动作电位诱导的Ca 2+瞬变。在PKA调节亚基的肽存在下，Ca 2 +-S100 A1的NMR化学位移扰动证实S100 A1直接与PKA相互作用，并且这种相互作用可能发生在Ca 2 +-S100 A1的疏水结合口袋中。我们的研究结果表明，在交感神经元外源性S100 A1可能会导致交感神经输出的增加的假设。
Hernandez-Ochoa EO, Prosser BL, Wright NT, Contreras M, Weber DJ, Schneider MF. Augmentation of Cav1 channel current and action potential duration after uptake of S100A1 in sympathetic ganglion neurons. Am J Physiol Cell Physiol 297: C955-C970, 2009. First published August 5, 2009; doi:10.1152/ajpcell.00140.2009.-S100A1, a 21-kDa dimeric Ca2+-binding protein of the EF-hand type, is expressed in cardiomyocytes and is an important regulator of heart function. During ischemia, cardiomyocytes secrete S100A1 to the extracellular space. Although the effects of extracellular S100A1 have been documented in cardiomyocytes, it is unclear whether S100A1 exerts modulatory effects on other tissues in proximity with cardiac cells. Therefore, we sought to investigate the effects of exogenous S100A1 on Ca2+ signals and electrical properties of superior cervical ganglion (SCG) neurons. Immunostaining and Western blot assays indicated no endogenous S100A1 in SCG neurons. Cultured SCG neurons took up S100A1 when it was present in the extracellular medium. Inside the cell exogenous S100A1 localized in a punctate pattern throughout the cytoplasm but was excluded from the nuclei. S100A1 partially colocalized with markers for both receptor-and non-receptor-mediated endocytosis, indicating that in SCG neurons multiple endocytotic pathways are involved in S100A1 internalization. In compartmentalized SCG cultures, axonal projections were capable of uptake and transport of S100A1 toward the neuronal somas. Exogenous S100A1 applied either extra-or intracellularly enhanced Ca(v)1 channel currents in a PKA-dependent manner, prolonged action potentials, and amplified action potential-induced Ca2+ transients. NMR chemical shift perturbation of Ca2+-S100A1 in the presence of a peptide from the regulatory subunit of PKA verifies that S100A1 directly interacts with PKA, and that this interaction likely occurs in the hydrophobic binding pocket of Ca2+-S100A1. Our results suggest the hypothesis that in sympathetic neurons exogenous S100A1 may lead to an increase of sympathetic output.