Mycobacterium tuberculosis WhiB4 regulates oxidative stress response to modulate survival and dissemination in vivo.
Mycobacterium tuberculosis WhiB4 regulates oxidative stress response to modulate survival and dissemination in vivo.
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DOI：
10.1111/j.1365-2958.2012.08165.x
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发表时间：
2012-09
影响因子：
3.6
通讯作者：
Singh A
中科院分区：
文献类型：
--
作者：
Chawla M;Parikh P;Saxena A;Munshi M;Mehta M;Mai D;Srivastava AK;Narasimhulu KV;Redding KE;Vashi N;Kumar D;Steyn AJ;Singh A
宿主产生的氧化应激被认为是限制结核分枝杆菌(Mtb)生长的主要机制之一。Mtb的氧化还原敏感机制尚不完全清楚。在这里，我们证明了WhiB4通过其4Fe-4S簇对氧(O2)和一氧化氮(NO)做出反应，并控制Mtb的氧化应激反应。WhiB4突变体(MtbΔWhiB4)表现出氧化还原平衡的改变和膜电位的降低。基因芯片分析表明，MtbΔWhiB4高表达抗氧化系统，包括烷基过氧化氢酶(AHPC-AHPD)和Ruba-RubB。DNA结合分析表明，WhiB4[4Fe-4S]簇是DNA结合所必需的。然而，apo-WhiB4半胱氨酸硫醇的氧化诱导了二硫键连接的寡聚、DNA结合和转录抑制，而还原则相反。此外，WhiB4结合DNA时偏爱富含GC的序列。表达分析表明，氧化应激抑制了Mtb中的WhiB4并诱导了抗氧化剂，而在Mtb的Δ中观察到了它们的超诱导作用。结核分枝杆菌ΔWhiB4在体外表现出对氧化应激的抵抗力，并提高了巨噬细胞内的存活率。最后，结核分枝杆菌ΔWhiB4在豚鼠肺内表现出超强毒力，但在向脾扩散方面存在缺陷。这些发现表明，WhiB4系统地校准Mtb中氧化应激反应的激活，以维持氧化还原平衡，并调节毒力。
Host-generated oxidative stress is considered one of the main mechanisms constraining Mycobacterium tuberculosis (Mtb) growth. The redox-sensing mechanisms in Mtb are not completely understood. Here we show that WhiB4 responds to oxygen (O2) and nitric oxide (NO) via its 4Fe-4S cluster and controls the oxidative stress response in Mtb. The WhiB4 mutant (MtbΔwhiB4) displayed an altered redox balance and a reduced membrane potential. Microarray analysis demonstrated that MtbΔwhiB4 overexpresses the antioxidant systems including alkyl hydroperoxidase (ahpC-ahpD) and rubredoxins (rubA-rubB). DNA binding assays showed that WhiB4 [4Fe-4S] cluster is dispensable for DNA binding. However, oxidation of the apo-WhiB4 Cys thiols induced disulphide-linked oligomerization, DNA binding and transcriptional repression, whereas reduction reversed the effect. Furthermore, WhiB4 binds DNA with a preference for GC-rich sequences. Expression analysis showed that oxidative stress repressed whiB4 and induced antioxidants in Mtb, while their hyper-induction was observed in MtbΔwhiB4. MtbΔwhiB4 showed increased resistance to oxidative stress in vitro and enhanced survival inside the macrophages. Lastly, MtbΔwhiB4 displayed hypervirulence in the lungs of guinea pigs, but showed a defect in dissemination to their spleen. These findings suggest that WhiB4 systematically calibrates the activation of oxidative stress response in Mtb to maintain redox balance, and to modulate virulence.
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影响因子：
4.4
作者：
Haft DH
通讯作者：
Haft DH
影响因子：
3.2
作者：
Fisher, MA;Plikaytis, BB;Shinnick, TM
通讯作者：
Shinnick, TM
影响因子：
3.1
作者：
Cooper, AM;Segal, BH;Orme, IM
通讯作者：
Orme, IM
影响因子：
4.8
作者：
Jakimowicz, P;Cheesman, MR;Buttner, MJ
通讯作者：
Buttner, MJ
影响因子：
3.1
作者：
Chackerian, AA;Alt, JM;Behar, SM
通讯作者：
Behar, SM