The Pseudomonas aeruginosa Complement of Lactate Dehydrogenases Enables Use of d- and l-Lactate and Metabolic Cross-Feeding.
The Pseudomonas aeruginosa Complement of Lactate Dehydrogenases Enables Use of d- and l-Lactate and Metabolic Cross-Feeding.
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DOI：
10.1128/mbio.00961-18
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发表时间：
2018-09-11
期刊：
影响因子：
6.4
通讯作者：
Dietrich LEP
中科院分区：
文献类型：
--
作者：
Lin YC;Cornell WC;Jo J;Price-Whelan A;Dietrich LEP
乳酸盐被认为是慢性感染期间的碳和能量来源。细菌定植的位点可以含有乳酸盐的两种对映体：通常由宿主产生的l-型和通常由细菌（包括肺部病原体铜绿假单胞菌）产生的d-型。在这里，我们表征了铜绿假单胞菌的四种酶，它可以用来相互转化丙酮酸和乳酸，其功能取决于氧的可用性和乳酸的特定对映体。我们还表明，厌氧丙酮酸发酵触发生产的好氧d-乳酸脱氢酶在液体培养物和生物膜，从而使代谢交叉喂养的乳酸随着时间和空间之间的细胞亚群。这些代谢途径可能有助于铜绿假单胞菌在肺中的生长和存活。铜绿假单胞菌是囊性纤维化（CF）患者慢性生物膜肺部感染的最常见原因。CF患者的痰液中含有含氧和缺氧亚区以及毫摩尔浓度的乳酸盐。在这里，我们描述的生理作用和铜绿假单胞菌乳酸脱氢酶的表达模式在不同的生长制度的背景下。铜绿假单胞菌产生注释为乳酸脱氢酶的四种酶，已知其中三种有助于液体培养物中的厌氧或需氧代谢。这三种是LdhA，其在厌氧存活期间将丙酮酸盐还原为d-乳酸盐，以及LldE和LldD，其在有氧生长期间分别氧化d-乳酸盐和l-乳酸盐。我们证明，第四种酶，LldA，进行多余的L-乳酸氧化在有氧培养生长过程中，在一个定义的MOPS（吗啉丙磺酸）为基础的培养基和合成CF痰液培养基。然而，LldA与LldD的不同之处在于其表达由乳酸盐的l-对映体特异性诱导。我们还表明，铜绿假单胞菌乳酸脱氢酶在菌落生物膜中的功能与它们在液体培养物中的功能相似。最后，我们提供的证据表明，酶LdhA和LldE有可能支持代谢交叉喂养的生物膜，其中LdhA可以催化生产的d-乳酸在厌氧区，然后用作底物在有氧区。总之，这些观察结果进一步加深了我们对CF肺部感染期间可能有助于铜绿假单胞菌生长和存活的代谢途径的理解。
Lactate is thought to serve as a carbon and energy source during chronic infections. Sites of bacterial colonization can contain two enantiomers of lactate: the l-form, generally produced by the host, and the d-form, which is usually produced by bacteria, including the pulmonary pathogen Pseudomonas aeruginosa. Here, we characterize P. aeruginosa’s set of four enzymes that it can use to interconvert pyruvate and lactate, the functions of which depend on the availability of oxygen and specific enantiomers of lactate. We also show that anaerobic pyruvate fermentation triggers production of the aerobic d-lactate dehydrogenase in both liquid cultures and biofilms, thereby enabling metabolic cross-feeding of lactate over time and space between subpopulations of cells. These metabolic pathways might contribute to P. aeruginosa growth and survival in the lung. Pseudomonas aeruginosa is the most common cause of chronic, biofilm-based lung infections in patients with cystic fibrosis (CF). Sputum from patients with CF has been shown to contain oxic and hypoxic subzones as well as millimolar concentrations of lactate. Here, we describe the physiological roles and expression patterns of P. aeruginosa lactate dehydrogenases in the contexts of different growth regimes. P. aeruginosa produces four enzymes annotated as lactate dehydrogenases, three of which are known to contribute to anaerobic or aerobic metabolism in liquid cultures. These three are LdhA, which reduces pyruvate to d-lactate during anaerobic survival, and LldE and LldD, which oxidize d-lactate and l-lactate, respectively, during aerobic growth. We demonstrate that the fourth enzyme, LldA, performs redundant l-lactate oxidation during growth in aerobic cultures in both a defined MOPS (morpholinepropanesulfonic acid)-based medium and synthetic CF sputum media. However, LldA differs from LldD in that its expression is induced specifically by the l-enantiomer of lactate. We also show that the P. aeruginosa lactate dehydrogenases perform functions in colony biofilms that are similar to their functions in liquid cultures. Finally, we provide evidence that the enzymes LdhA and LldE have the potential to support metabolic cross-feeding in biofilms, where LdhA can catalyze the production of d-lactate in the anaerobic zone, which is then used as a substrate in the aerobic zone. Together, these observations further our understanding of the metabolic pathways that can contribute to P. aeruginosa growth and survival during CF lung infection.