Espinal-Enríquez Jesús, Darszon Alberto, Guerrero Adán, Martínez-Mekler Gustavo
Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México; Centro de Ciencias de la Complejidad, Ciudad Universitaria, México, México; Instituto Nacional de Medicina Genómica, Arenal Tepepan, Tlalpan, México.
Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
PLoS One. 2014 Aug 27;9(8):e104451. doi: 10.1371/journal.pone.0104451. eCollection 2014.
The motility of spermatozoa of both Lytechinus pictus and Strongylocentrotus purpuratus sea urchin species is modulated by the egg-derived decapeptide speract via an oscillatory [Ca2+]-dependent signaling pathway. Comprehension of this pathway is hence directly related to the understanding of regulated sperm swimming. Niflumic acid (NFA), a nonsteroidal anti-inflammatory drug alters several ion channels. Though unspecific, NFA profoundly affects how sea urchin sperm respond to speract, increasing the [Ca2+]i oscillation period, amplitude, peak and average level values of the responses in immobilized and swimming cells. A previous logical network model we developed for the [Ca2+] dynamics of speract signaling cascade in sea urchin sperm allows integrated dissection of individual and multiple actions of NFA. Among the channels affected by NFA are: hyperpolarization-activated and cyclic nucleotide gated Na+ channels (HCN), [Ca2+]-dependent Cl- channels (CaCC) and [Ca2+]-dependent K+ channels (CaKC), all present in the sea urchin genome. Here, using our model we investigated the effect of blocking in silico HCN and CaCC channels suggested by experiments. Regarding CaKC channels, arguments can be provided for either their blockage or activation by NFA. Our study yielded two scenarios compliant with experimental observations: i) under CaKC inhibition, this [Ca2+]-dependent K+ channel should be different from the Slo1 channel and ii) under activation of the CaKC channel, another [Ca2+] channel not considered previously in the network is required, such as the pH-dependent CatSper channel. Additionally, our findings predict cause-effect relations resulting from a selective inhibition of those channels. Knowledge of these relations may be of consequence for a variety of electrophysiological studies and have an impact on drug related investigations. Our study contributes to a better grasp of the network dynamics and suggests further experimental work.
太平洋紫球海胆和紫海胆这两种海胆精子的运动性,是由卵子来源的十肽精子活化肽(speract)通过一条振荡性的、依赖钙离子的信号通路来调节的。因此,对这条信号通路的理解直接关系到对精子游泳调控的认识。氟尼辛(NFA)是一种非甾体类抗炎药,它会改变多种离子通道。尽管作用不具有特异性,但NFA会深刻影响海胆精子对精子活化肽的反应,增加固定和游动细胞中反应的钙离子内流([Ca2+]i)振荡周期、振幅、峰值和平均水平值。我们之前为海胆精子中精子活化肽信号级联的钙离子动态建立的逻辑网络模型,能够对NFA的个体和多种作用进行综合剖析。受NFA影响的通道包括:超极化激活的环核苷酸门控钠离子通道(HCN)、钙离子依赖的氯离子通道(CaCC)和钙离子依赖的钾离子通道(CaKC),这些通道都存在于海胆基因组中。在这里,我们使用我们的模型研究了实验所提示的在计算机模拟中阻断HCN和CaCC通道的效果。关于CaKC通道,有证据支持NFA对其产生阻断或激活作用。我们的研究得出了两种与实验观察结果相符的情况:i)在CaKC通道受到抑制的情况下,这种钙离子依赖的钾离子通道应该与Slo1通道不同;ii)在CaKC通道被激活的情况下,网络中之前未被考虑的另一种钙离子通道是必需的,比如pH依赖的精子阳离子通道(CatSper)。此外,我们的研究结果预测了选择性抑制这些通道所产生的因果关系。了解这些关系可能对各种电生理研究具有重要意义,并对药物相关研究产生影响。我们的研究有助于更好地理解网络动态,并建议进一步开展实验工作。