Purpose

Oxidative stress is an essential component of innate response against microbes. The oxidative impact has a very subtle connection with apoptosis. Our previous work indicated presumptive evidence of apoptosis by the chalcone derivatives against the human lymphatic filarial parasite. Evidence suggests the involvement of glutathione-S-transferase (GST) in the mechanism of action of chalcone drugs. In the present study, we explored the implications of redox status in apoptosis of the parasite by this drug.

Results

Treatment with the representative drug, 4t, significantly decreased GSH level and increased GST activity in the Brugia malayi microfilariae (Mf) in comparison to Mf without 4t treatment. Drug-induced loss of motility of the parasites was reversed by the treatment with GSH (41%) and NAC (19%). A significant fall in rGST activity was observed due to drug addition, which could be reversed by the addition of GSH co-substrate, but not with the re-addition of rGST, indicating a vital role of GSH. In silico study demonstrated a favorable drug–GST enzyme interaction. Oxidative stress was reflected by increased protein carbonylation and intracellular reactive oxygen species level, in the drug-treated parasite. Mitochondrial oxygen consumption was reduced by the drug, which was reversed on the addition of GSH. Mitochondrial dysfunction was confirmed by MTT and cytochrome c assay. Apoptosis was confirmed by the inhibition in PARP activity.

Conclusion

We conclude that the depletion of GSH by chalcone with concomitant mitochondrial dysfunction revealed a novel rationale of apoptosis in the parasite. Such a mechanism might have wide therapeutic implications.

中文翻译：

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谷胱甘肽在查尔酮衍生物诱导的马来亚种细胞凋亡中的作用及其可能的治疗意义

目的

氧化应激是对微生物的先天反应的重要组成部分。氧化作用与细胞凋亡有着非常微妙的联系。我们以前的工作表明，查耳酮衍生物对人淋巴丝虫寄生虫有细胞凋亡的推定证据。有证据表明谷胱甘肽-S-转移酶(GST) 参与查尔酮药物的作用机制。在本研究中，我们探讨了氧化还原状态对这种药物对寄生虫凋亡的影响。

结果

用代表性药物 4t 治疗，显着降低了马来亚人的GSH 水平并增加了 GST 活性微丝蚴 (Mf) 与未经 4t 处理的 Mf 相比。用 GSH (41%) 和 NAC (19%) 治疗可以逆转药物引起的寄生虫运动性丧失。由于添加药物，观察到 rGST 活性的显着下降，这可以通过添加 GSH 共底物来逆转，但不能通过重新添加 rGST 来逆转，表明 GSH 的重要作用。计算机模拟研究证明了有利的药物-GST 酶相互作用。在药物处理的寄生虫中，氧化应激通过增加的蛋白质羰基化和细胞内活性氧水平反映出来。该药物降低了线粒体耗氧量，而加入 GSH 后，这种情况发生逆转。MTT和细胞色素c测定证实了线粒体功能障碍。通过抑制PARP活性证实了细胞凋亡。

结论

我们得出结论，查耳酮消耗 GSH 并伴随线粒体功能障碍揭示了寄生虫凋亡的新原理。这种机制可能具有广泛的治疗意义。