Inhibition of the sodium-translocating NADH-ubiquinone oxidoreductase [Na+-NQR] decreases cholera toxin production in Vibrio cholerae 01 at the late exponential growth phase
Inhibition of the sodium-translocating NADH-ubiquinone oxidoreductase [Na+-NQR] decreases cholera toxin production in Vibrio cholerae 01 at the late exponential growth phase
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DOI：
10.1016/j.micpath.2013.12.002
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发表时间：
2014-01-01
影响因子：
3.8
通讯作者：
Haese, Claudia C.
中科院分区：
文献类型：
--
作者：
Minato, Yusuke;Fassio, Sara R.;Haese, Claudia C.
霍乱弧菌产生的两种毒力因子，霍乱毒素（CT）和毒素相关菌（TCP），是霍乱感染不可缺少的。ToxT是参与激活CT和TCP表达的中心调节蛋白。我们之前报道过，缺乏与呼吸相关的钠易位nadh -泛醌氧化还原酶（Na+-NQR）可显著增加toxT转录。在这项研究中，我们进一步表征了这一联系，发现Na+-NQR仅在log生长早期影响toxT的表达，而Na+-NQR的缺乏会在log生长中期后降低CT的产生。这种减少的CT产生与toxT和ctxB转录无关。在生长培养基中添加呼吸底物l -乳酸恢复了nqrA-F突变体的产量，这表明Na+-NQR突变体中CT产量的下降依赖于电子传递链（ETC）活性。这一观点得到了两种化学抑制剂的支持，一种是Na+-NQR特异性抑制剂2-n- heptyl -4-羟基喹啉n-氧化物（HQNO），另一种是琥珀酸脱氢酶（SDH）抑制剂，甲基三氟丙酮（TTFA），强烈抑制经典和El Tor生物型霍乱杆菌的CT产生。因此，我们提出霍乱弧菌的主要呼吸酶作为治疗霍乱的潜在药物靶点，因为人类线粒体不含Na+-NQR同源物。(C) 2013 Elsevier Ltd.版权所有。
Two virulence factors produced by Vibrio cholerae, cholera toxin (CT) and toxin-corregulated pilus (TCP), are indispensable for cholera infection. ToxT is the central' regulatory protein involved in activation of CT and TCP expression. We previously reported that lack of a respiration-linked sodium-translocating NADH-ubiquinone oxidoreductase (Na+-NQR) significantly increases toxT transcription. In this study, we further characterized this link and found that Na+-NQR affects toxT expression only at the early-log growth phase, whereas lack of Na+-NQR decreases CT production after the mid-log growth phase. Such decreased CT production was independent of toxT and ctxB transcription. Supplementing a respiratory substrate, L-lactate, into the growth media restored a production in the nqrA-F mutant, suggesting that decreased CT production in the Na+-NQR mutant is dependent on electron transport chain (ETC) activity. This notion was supported by the observations that two chemical inhibitors, a Na+-NQR specific inhibitor 2-n-Heptyl-4-hydroxyquinoline N-oxide (HQNO) and a succinate dehydrogenase (SDH) inhibitor, thenoyltrifluoroacetone (TTFA), strongly inhibited CT production in both classical and El Tor biotype strains of V. cholerae. Accordingly, we propose the main respiratory enzyme of V cholerae, as a potential drug target to treat cholera because human mitochondria do not contain Na+-NQR orthologs. (C) 2013 Elsevier Ltd. All rights reserved.