Eradication of Intracellular Salmonella enterica Serovar Typhimurium with a Small-Molecule, Host Cell-Directed Agent
Eradication of Intracellular Salmonella enterica Serovar Typhimurium with a Small-Molecule, Host Cell-Directed Agent
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DOI：
10.1128/aac.00555-09
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发表时间：
2009-12-01
影响因子：
4.9
通讯作者：
Chen, Ching-Shih
中科院分区：
文献类型：
--
作者：
Chiu, Hao-Chieh;Kulp, Samuel K.;Chen, Ching-Shih
用宿主导向的化学试剂根除细胞内致病菌一直是治疗耐药细菌的预期创新。我们先前合成并表征了一种新型小分子药物AR-12，其诱导自噬并抑制癌细胞中的Akt激酶。由于自噬和Akt激酶最近已被证明在几种细胞内细菌（包括鼠伤寒沙门氏菌）的细胞内存活中起作用，我们研究了AR-12对巨噬细胞中鼠伤寒沙门氏菌的细胞内存活的影响。我们的研究结果表明，AR-12诱导巨噬细胞中的自噬，如自噬体形成增加所示，并有效地抑制巨噬细胞中鼠伤寒血清型的存活，与细胞内细菌与自噬体的共定位增加有关。在AR-12存在下，通过短发夹RNA介导的巨噬细胞中Beclin-1或Atg 7的敲低，部分挽救了细胞内细菌生长。此外，AR-12抑制感染的巨噬细胞中的Akt激酶活性，我们证明这对其抗菌作用很重要，因为这些细胞中组成性激活的Akt 1的强制表达逆转了AR-12诱导的对细胞内鼠伤寒血清型存活的抑制。最后，以2.5 mg/kg/天剂量经口给予血清型Typhimurium感染小鼠AR-12可降低肝脏和脾脏细菌负荷，并显著延长存活期。这些研究结果表明，AR-12代表了一个原则的证据，即细胞内细菌的存活可以被靶向先天免疫和由细菌调节的宿主细胞因子的小分子试剂抑制。
Eradication of intracellular pathogenic bacteria with host-directed chemical agents has been an anticipated innovation in the treatment of antibiotic-resistant bacteria. We previously synthesized and characterized a novel small-molecule agent, AR-12, that induces autophagy and inhibits the Akt kinase in cancer cells. As both autophagy and the Akt kinase have been shown recently to play roles in the intracellular survival of several intracellular bacteria, including Salmonella enterica serovar Typhimurium, we investigated the effect of AR-12 on the intracellular survival of Salmonella serovar Typhimurium in macrophages. Our results show that AR-12 induces autophagy in macrophages, as indicated by increased autophagosome formation, and potently inhibits the survival of serovar Typhimurium in macrophages in association with increased colocalization of intracellular bacteria with autophagosomes. Intracellular bacterial growth was partially rescued in the presence of AR-12 by the short hairpin RNA-mediated knockdown of Beclin-1 or Atg7 in macrophages. Moreover, AR-12 inhibits Akt kinase activity in infected macrophages, which we show to be important for its antibacterial effect as the enforced expression of constitutively activated Akt1 in these cells reverses the AR-12-induced inhibition of intracellular serovar Typhimurium survival. Finally, oral administration of AR-12 at 2.5 mg/kg/day to serovar Typhimurium-infected mice reduced hepatic and splenic bacterial burdens and significantly prolonged survival. These findings show that AR-12 represents a proof of principle that the survival of intracellular bacteria can be suppressed by small-molecule agents that target both innate immunity and host cell factors modulated by bacteria.