Flores Pedro L, Rodríguez Emma, Zapata Estrella, Carbó Roxana, Farías José María, Martínez Martín
Departamento de Instrumentación Electromecánica, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano # 1, Col. Sección XVI, México City 14080, Mexico.
Laboratorio de Biología Celular, Departamento de Fisiología, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano # 1, Col. Sección XVI, México City 14080, Mexico.
Mar Drugs. 2017 Jun 25;15(7):198. doi: 10.3390/md15070198.
Maitotoxin (MTX) is the most potent marine toxin known to date. It is responsible for a particular human intoxication syndrome called (CFP). Several reports indicate that MTX is an activator of non-selective cation channels (NSCC) in different cell types. The molecular identity of these channels is still an unresolved topic, and it has been proposed that the transient receptor potential (TRP) channels are involved in this effect. In oocytes, MTX at picomolar (pM) concentrations induces the activation of NSCC with functional and pharmacological properties that resemble the activity of TRP channels. The purpose of this study was to characterize the molecular identity of the TRP channel involved in the MTX response, using the small interference RNA (siRNA) approach and the two-electrode voltage-clamp technique (TEVC). The injection of a specifically designed siRNA to silence the transient receptor potential canonical type 1 (TRPC1) protein expression abolished the MTX response. MTX had no effect on oocytes, even at doses 20-fold higher compared to cells without injection. Total mRNA and protein levels of TRPC1 were notably diminished. The TRPC4 siRNA did not change the MTX effect, even though it was important to note that the protein level was reduced by the silencing of TRPC4. Our results suggest that MTX could be a selective activator of TRPC1 channels in oocytes and a useful pharmacological tool for further studies on these TRP channels.
maitotoxin（MTX）是迄今为止已知的最具毒性的海洋毒素。它会引发一种名为（CFP）的特定人类中毒综合征。多项报告表明，MTX是不同细胞类型中非选择性阳离子通道（NSCC）的激活剂。这些通道的分子身份仍是一个未解决的问题，有人提出瞬时受体电位（TRP）通道参与了这一效应。在卵母细胞中，皮摩尔（pM）浓度的MTX会诱导NSCC的激活，其功能和药理学特性类似于TRP通道的活性。本研究的目的是使用小干扰RNA（siRNA）方法和双电极电压钳技术（TEVC）来确定参与MTX反应的TRP通道的分子身份。注射专门设计的siRNA以沉默瞬时受体电位经典1型（TRPC1）蛋白表达，消除了MTX反应。即使与未注射的细胞相比剂量高出20倍，MTX对卵母细胞也没有影响。TRPC1的总mRNA和蛋白水平显著降低。TRPC4 siRNA并没有改变MTX的作用效果，尽管需要注意的是，TRPC4的沉默降低了其蛋白水平。我们的结果表明，MTX可能是卵母细胞中TRPC1通道的选择性激活剂，并且是进一步研究这些TRP通道的有用药理学工具。
