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Florek LC, Lin X, Lin YC, Lin MH, Chakraborty A, Price-Whelan A, Tong L, Rahme L, Dietrich LE. The L-lactate dehydrogenases of Pseudomonas aeruginosa are conditionally regulated but both contribute to survival during macrophage infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586142. [PMID: 38562866 PMCID: PMC10983889 DOI: 10.1101/2024.03.21.586142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that thrives in environments associated with human activity, including soil and water altered by agriculture or pollution. Because L-lactate is a significant product of plant and animal metabolism, it is available to serve as a carbon source for P. aeruginosa in the diverse settings it inhabits. Here, we evaluate P. aeruginosa's production and use of its redundant L-lactate dehydrogenases, termed LldD and LldA. We confirm that the protein LldR represses lldD and identify a new transcription factor, called LldS, that activates lldA; these distinct regulators and the genomic contexts of lldD and lldA contribute to their differential expression. We demonstrate that the lldD and lldA genes are conditionally controlled in response to lactate isomers as well as to glycolate and - hydroxybutyrate, which, like lactate, are -hydroxycarboxylates. We also show that lldA is induced when iron availability is low. Our examination of lldD and lldA expression across depth in biofilms indicates a complex pattern that is consistent with the effects of glycolate production, iron availability, and cross-regulation on enzyme preference. Finally, macrophage infection assays revealed that both lldD and lldA contribute to persistence within host cells, underscoring the potential role of L-lactate as a carbon source during P. aeruginosa-eukaryote interactions. Together, these findings help us understand the metabolism of a key resource that may promote P. aeruginosa's success as a resident of contaminated environments and animal hosts.
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Affiliation(s)
- Lindsey C. Florek
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Xi Lin
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Yu-Cheng Lin
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan 112
| | - Min-Han Lin
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Arijit Chakraborty
- Department of Surgery, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children Boston, Boston, Massachusetts, USA
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Laurence Rahme
- Department of Surgery, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children Boston, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10027
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Sánchez-Jiménez A, Llamas MA, Marcos-Torres FJ. Transcriptional Regulators Controlling Virulence in Pseudomonas aeruginosa. Int J Mol Sci 2023; 24:11895. [PMID: 37569271 PMCID: PMC10418997 DOI: 10.3390/ijms241511895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 08/13/2023] Open
Abstract
Pseudomonas aeruginosa is a pathogen capable of colonizing virtually every human tissue. The host colonization competence and versatility of this pathogen are powered by a wide array of virulence factors necessary in different steps of the infection process. This includes factors involved in bacterial motility and attachment, biofilm formation, the production and secretion of extracellular invasive enzymes and exotoxins, the production of toxic secondary metabolites, and the acquisition of iron. Expression of these virulence factors during infection is tightly regulated, which allows their production only when they are needed. This process optimizes host colonization and virulence. In this work, we review the intricate network of transcriptional regulators that control the expression of virulence factors in P. aeruginosa, including one- and two-component systems and σ factors. Because inhibition of virulence holds promise as a target for new antimicrobials, blocking the regulators that trigger the production of virulence determinants in P. aeruginosa is a promising strategy to fight this clinically relevant pathogen.
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Affiliation(s)
| | - María A. Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
| | - Francisco Javier Marcos-Torres
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain;
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Kristensen SS, Diep DB, Kjos M, Mathiesen G. The role of site-2-proteases in bacteria: a review on physiology, virulence, and therapeutic potential. MICROLIFE 2023; 4:uqad025. [PMID: 37223736 PMCID: PMC10202637 DOI: 10.1093/femsml/uqad025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/21/2023] [Accepted: 05/02/2023] [Indexed: 05/25/2023]
Abstract
Site-2-proteases are a class of intramembrane proteases involved in regulated intramembrane proteolysis. Regulated intramembrane proteolysis is a highly conserved signaling mechanism that commonly involves sequential digestion of an anti-sigma factor by a site-1- and site-2-protease in response to external stimuli, resulting in an adaptive transcriptional response. Variation of this signaling cascade continues to emerge as the role of site-2-proteases in bacteria continues to be explored. Site-2-proteases are highly conserved among bacteria and play a key role in multiple processes, including iron uptake, stress response, and pheromone production. Additionally, an increasing number of site-2-proteases have been found to play a pivotal role in the virulence properties of multiple human pathogens, such as alginate production in Pseudomonas aeruginosa, toxin production in Vibrio cholerae, resistance to lysozyme in enterococci and antimicrobials in several Bacillus spp, and cell-envelope lipid composition in Mycobacterium tuberculosis. The prominent role of site-2-proteases in bacterial pathogenicity highlights the potential of site-2-proteases as novel targets for therapeutic intervention. In this review, we summarize the role of site-2-proteases in bacterial physiology and virulence, as well as evaluate the therapeutic potential of site-2-proteases.
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Affiliation(s)
- Sofie S Kristensen
- Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), 1433 Ås, Norway
| | | | - Morten Kjos
- Corresponding author. NMBU, P.O. Box 5003, 1433 Ås, Norway. E-mail:
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Cornelis P, Tahrioui A, Lesouhaitier O, Bouffartigues E, Feuilloley M, Baysse C, Chevalier S. High affinity iron uptake by pyoverdine in Pseudomonas aeruginosa involves multiple regulators besides Fur, PvdS, and FpvI. Biometals 2023; 36:255-261. [PMID: 35171432 DOI: 10.1007/s10534-022-00369-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 02/03/2022] [Indexed: 11/02/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative bacterium which can cause serious infections among immune-depressed people including cystic fibrosis patients where it can colonize the lungs causing chronic infections. Iron is essential for P. aeruginosa and can be provided via three sources under aerobic conditions: its own siderophores pyochelin (PCH) and pyoverdine (PVD), xenosiderophores, or heme, respectively. Pyoverdine is the high affinity siderophore and its synthesis and uptake involve more than 30 genes organized in different operons. Its synthesis and uptake are triggered by iron scarcity via the Fur regulator and involves two extra cytoplasmic sigma factors (ECF), PvdS for the biosynthesis of PVD and FpvI for the uptake via the TonB-dependent FpvA outer membrane transporter and other periplasmic and inner membrane proteins. It appeared recently that the regulation of PVD biosynthesis and uptake involves other regulators, including other ECF factors, and LysR regulators. This is the case especially for the genes coding for periplasmic and inner membrane proteins involved in the reduction of Fe3+ to Fe2+ and the transport of ferrous iron to the cytoplasm that appears to represent a crucial step in the uptake process.
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Affiliation(s)
- Pierre Cornelis
- Laboratory of Microbiology Signals and Microenvironnements (LMSM) EA 4312, University of Rouen Normandy, 27000, Evreux, France.
- Laboratorium Microbiologie, Vrije Universiteit Brussel, Brussels, Belgium.
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironnements (LMSM) EA 4312, University of Rouen Normandy, 27000, Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironnements (LMSM) EA 4312, University of Rouen Normandy, 27000, Evreux, France
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironnements (LMSM) EA 4312, University of Rouen Normandy, 27000, Evreux, France
| | - Marc Feuilloley
- Laboratory of Microbiology Signals and Microenvironnements (LMSM) EA 4312, University of Rouen Normandy, 27000, Evreux, France
| | - Christine Baysse
- CNRS, Institut de Génétique et de Développement de Rennes (IGDR), UMR6290, Université de Rennes, Rennes, France
| | - Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironnements (LMSM) EA 4312, University of Rouen Normandy, 27000, Evreux, France
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High-Level Expression of Cell-Surface Signaling System Hxu Enhances Pseudomonas aeruginosa Bloodstream Infection. Infect Immun 2022; 90:e0032922. [PMID: 36169312 PMCID: PMC9584290 DOI: 10.1128/iai.00329-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bloodstream infections (BSIs) caused by Pseudomonas aeruginosa are associated with a high mortality rate in the clinic. However, the fitness mechanisms responsible for the evolution of virulence factors that facilitate the dissemination of P. aeruginosa to the bloodstream are poorly understood. In this study, a transcriptomic analysis of the BSI-associated P. aeruginosa clinical isolates showed a high-level expression of cell-surface signaling (CSS) system Hxu. Whole-genome sequencing and comparative genomics of these isolates showed that a mutation in rnfE gene was responsible for the elevated expression of the Hxu-CSS pathway. Most importantly, deletion of the hxuIRA gene cluster in a laboratory strain PAO1 reduced its BSI capability while overexpression of the HxuIRA pathway promoted BSI in a murine sepsis model. We further demonstrated that multiple components in the blood plasma, including heme, hemoglobin, the heme-scavenging proteins haptoglobin, and hemopexin, as well as the iron-delivery protein transferrin, could activate the Hxu system. Together, these studies suggested that the Hxu-CSS system was an important signal transduction pathway contributing to the adaptive pathogenesis of P. aeruginosa in BSI.
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