GEA3162, a nitric oxide-releasing agent, activates non-store-operated Ca²⁺ entry and inhibits store-operated Ca²⁺ entry pathways in neutrophils through thiol oxidation

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• 作者：Mei-Feng Hsu ; Yu-San Chen ; Li-Jiau Huang ; Lo-Ti Tsao ; Sheng-Chu Kuo and Jih-Pyang Wang
• 关键词：GEA3162 ; Neutrophil ; Thiol oxidation ; Store-operated Ca²⁺ entry ; Protein tyrosine phosphorylation ; Actin reorganization
• 刊名：European Journal of Pharmacology
• 出版年：2006
• 出版时间：27 March 2006
• 年：2006
• 卷：535
• 期：1-3
• 页码：43-52
• 全文大小：333 K

文摘

We demonstrated that 5-amino-3-(3,4-dichlorophenyl)1,2,3,4-oxatriazolium (GEA3162), a nitric oxide (NO)-releasing agent, stimulated [Ca²⁺]_i rise in rat neutrophils. This Ca²⁺ response was prevented by the thiol reducing agents, 2-mercaptoethanol, N-acetyl-l-cysteine, dithiothreitol, 2,3-dimercaptopropane-1-sulfonic acid (DMPS) and tris-(2-carboxyethyl)phosphine (TCEP), but slightly reduced by the antioxidant, 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). GEA3162 also increased the formation of cellular reactive oxygen intermediates and decreased the cellular content of low molecular thiols. These responses were greatly reduced by Trolox, dithiothreitol and N-acetyl-l-cysteine. GEA3162 stimulated the protein tyrosine phosphorylation in neutrophils. The [Ca²⁺]_i rise caused by formyl-Met-Leu-Phe (fMLP) and cyclopiazonic acid (CPA) was suppressed by GEA3162. TCEP prevented the inhibition of fMLP-induced [Ca²⁺]_i rise by GEA3162. In the absence of external Ca²⁺, GEA3162 inhibited the CPA-induced [Ca²⁺]_i rise, whereas it only slightly affected the fMLP-induced mobilization of the Ca²⁺ store. Application of GEA3162 after the stimulation with fMLP or CPA suppressed the robust Ca²⁺ entry followed by the readdition of Ca²⁺ into medium. Moreover, the Ca²⁺ entry was more susceptible to inhibition by treatment with GEA3162 prior to than after the fMLP stimulation. GEA3162 had no effect on the mitochondrial membrane potential. GEA3162 induced actin reorganization and condensed filament network at the cell periphery. These results indicate that GEA3162 exerted both the stimulation of Ca²⁺ entry and the inhibition of the store-operated Ca²⁺ entry in rat neutrophils. The dual effects of GEA3162 on the regulation of the external Ca²⁺ entry are mainly through the thiol modification of target protein(s) residing on the outside of the plasma membrane.