c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation.
c-di-AMP modulates Listeria monocytogenes central metabolism to regulate growth, antibiotic resistance and osmoregulation.
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DOI：
10.1111/mmi.13622
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发表时间：
2017-04
影响因子：
3.6
通讯作者：
Portnoy DA
中科院分区：
文献类型：
--
作者：
Whiteley AT;Garelis NE;Peterson BN;Choi PH;Tong L;Woodward JJ;Portnoy DA
环二磷酸腺苷（c-di-AMP）是一种保守的核苷酸第二信使，对细菌生长和对细胞壁活性抗生素的抗性至关重要。在单核细胞增生李斯特菌中，唯一的二腺苷酸环化酶DacA在丰富但非合成的培养基中是必需的，并且ΔdacA突变体对β-内酰胺抗生素头孢呋辛高度敏感。在这项研究中，寡肽导入子（oppABCDF）和甘氨酸甜菜碱导入子（gbuABC）的功能缺失突变允许ΔdacA突变体在丰富培养基中生长。寡肽足以抑制ΔdacA突变体的生长，我们假设寡肽作为渗透剂，类似于甘氨酸甜菜碱，破坏细胞内渗透压。盐的补充使ΔdacA突变体在丰富培养基中稳定，并恢复头孢呋辛抗性。丙酮酸羧化酶（PycA）乙酰辅酶A结合位点的额外抑制突变挽救了头孢呋辛耐药性，并导致ΔdacA突变体的毒力增加100倍。PycA被c-di-AMP抑制，这些突变促使我们研究TCA循环酶的作用。柠檬酸合酶的失活，而不是下游酶抑制ΔdacA表型。这些数据表明，c-di-AMP调节丙酮酸结的中枢代谢，以调节柠檬酸盐的产生，实际上，ΔdacA突变体积累的柠檬酸盐浓度是野生型细菌中的6倍。c-di-AMP是许多细菌中必需的核苷酸第二信使。在这份报告中，Whiteley等人证明了单核细胞增生李斯特菌丙酮酸羧化酶乙酰辅酶A结合位点的抑制突变恢复了生长、对细胞壁抗生素的抗性以及不能产生c-di-AMP的突变体的毒力。这些数据表明，c-di-AMP调节丙酮酸结的中枢代谢，这是必要的可选的生长，代谢调节和毒力。
Cyclic di-adenosine monophosphate (c-di-AMP) is a conserved nucleotide second messenger critical for bacterial growth and resistance to cell wall-active antibiotics. In Listeria monocytogenes, the sole diadenylate cyclase, DacA, is essential in rich, but not synthetic media and ΔdacA mutants are highly sensitive to the β-lactam antibiotic cefuroxime. In this study, loss of function mutations in the oligopeptide importer (oppABCDF) and glycine betaine importer (gbuABC) allowed ΔdacA mutants to grow in rich medium. Oligopeptides were sufficient to inhibit growth of the ΔdacA mutant and we hypothesized that oligopeptides act as osmolytes, similar to glycine betaine, to disrupt intracellular osmotic pressure. Supplementation with salt stabilized the ΔdacA mutant in rich medium and restored cefuroxime resistance. Additional suppressor mutations in the acetyl-CoA binding site of pyruvate carboxylase (PycA) rescued cefuroxime resistance and resulted in a 100-fold increase in virulence of the ΔdacA mutant. PycA is inhibited by c-di-AMP and these mutations prompted us to examine the role of TCA cycle enzymes. Inactivation of citrate synthase, but not down-stream enzymes suppressed ΔdacA phenotypes. These data suggested that c-di-AMP modulates central metabolism at the pyruvate node to moderate citrate production and indeed, the ΔdacA mutant accumulated 6-times the concentration of citrate present in wild-type bacteria. c-di-AMP is an essential nucleotide second messenger in many bacteria. In this report, Whiteley et al. demonstrate that suppressor mutations in the acetyl-CoA binding site of Listeria monocytogenes pyruvate carboxylase restore growth, resistance to cell-wall antibiotics, and virulence of a mutant unable to produce c-di-AMP. These data suggest that c-di-AMP modulates central metabolism at the pyruvate node, which is necessary for optional growth, osmoregulation, and virulence.