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Barbarek SC, Shah R, Paul S, Alvarado G, Appala K, Phillips C, Henderson EC, Strandquist ET, Pokorny A, Singh VK, Gatto C, Dahl JU, Hines KM, Wilkinson BJ. Lipidomics of homeoviscous adaptation to low temperatures in Staphylococcus aureus utilizing exogenous straight-chain unsaturated fatty acids. J Bacteriol 2024; 206:e0018724. [PMID: 38953643 DOI: 10.1128/jb.00187-24] [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: 05/16/2024] [Accepted: 06/09/2024] [Indexed: 07/04/2024] Open
Abstract
It is well established that Staphylococcus aureus can incorporate exogenous straight-chain unsaturated fatty acids (SCUFAs) into membrane phospho- and glyco-lipids from various sources in supplemented culture media and when growing in vivo during infection. Given the enhancement of membrane fluidity when oleic acid (C18:1Δ9) is incorporated into lipids, we were prompted to examine the effect of medium supplementation with C18:1Δ9 on growth at low temperatures. C18:1Δ9 supported the growth of a cold-sensitive, branched-chain fatty acid (BCFA)-deficient mutant at 12°C. Interestingly, we found similar results in the BCFA-sufficient parental strain, supported by the fact that the incorporation of C18:1Δ9 into the membrane increased membrane fluidity in both strains. We show that the incorporation of C18:1Δ9 and its elongation product C20:1Δ11 into membrane lipids was required for growth stimulation and relied on a functional FakAB incorporation system. Lipidomics analysis of the phosphatidylglycerol and diglycosyldiacylglycerol lipid classes revealed major impacts of C18:1Δ9 and temperature on lipid species. Growth at 12°C in the presence of C18:1Δ9 also led to increased production of the carotenoid pigment staphyloxanthin. The enhancement of growth by C18:1Δ9 is an example of homeoviscous adaptation to low temperatures utilizing an exogenous fatty acid. This may be significant in the growth of S. aureus at low temperatures in foods that commonly contain C18:1Δ9 and other SCUFAs in various forms. IMPORTANCE We show that Staphylococcus aureus can use its known ability to incorporate exogenous fatty acids to enhance its growth at low temperatures. Individual species of phosphatidylglycerols and diglycosyldiacylglycerols bearing one or two degrees of unsaturation derived from the incorporation of C18:1Δ9 at 12°C are described for the first time. In addition, enhanced production of the carotenoid staphyloxanthin occurs at low temperatures. The studies describe a biochemical reality underlying membrane biophysics. This is an example of homeoviscous adaptation to low temperatures utilizing exogenous fatty acids over the regulation of the biosynthesis of endogenous fatty acids. The studies have likely relevance to food safety in that unsaturated fatty acids may enhance the growth of S. aureus in the food environment.
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Affiliation(s)
- Shannon C Barbarek
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Ritika Shah
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Sharanya Paul
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Gloria Alvarado
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Keerthi Appala
- Department of Chemistry, University of Georgia, Athens, Georgia, USA
| | - Caiden Phillips
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Emma C Henderson
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Evan T Strandquist
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina-Wilmington, Wilmington, North Carolina, USA
| | - Vineet K Singh
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, Kirksville, Missouri, USA
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Jan-Ulrik Dahl
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
| | - Kelly M Hines
- Department of Chemistry, University of Georgia, Athens, Georgia, USA
| | - Brian J Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois, USA
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2
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Huang H, Chang S, Cui T, Huang M, Qu J, Zhang H, Lu T, Zhang X, Zhou C, Feng Y. An inhibitory mechanism of AasS, an exogenous fatty acid scavenger: Implications for re-sensitization of FAS II antimicrobials. PLoS Pathog 2024; 20:e1012376. [PMID: 39008531 DOI: 10.1371/journal.ppat.1012376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 07/25/2024] [Accepted: 06/26/2024] [Indexed: 07/17/2024] Open
Abstract
Antimicrobial resistance is an ongoing "one health" challenge of global concern. The acyl-ACP synthetase (termed AasS) of the zoonotic pathogen Vibrio harveyi recycles exogenous fatty acid (eFA), bypassing the requirement of type II fatty acid synthesis (FAS II), a druggable pathway. A growing body of bacterial AasS-type isoenzymes compromises the clinical efficacy of FAS II-directed antimicrobials, like cerulenin. Very recently, an acyl adenylate mimic, C10-AMS, was proposed as a lead compound against AasS activity. However, the underlying mechanism remains poorly understood. Here we present two high-resolution cryo-EM structures of AasS liganded with C10-AMS inhibitor (2.33 Å) and C10-AMP intermediate (2.19 Å) in addition to its apo form (2.53 Å). Apart from our measurements for C10-AMS' Ki value of around 0.6 μM, structural and functional analyses explained how this inhibitor interacts with AasS enzyme. Unlike an open state of AasS, ready for C10-AMP formation, a closed conformation is trapped by the C10-AMS inhibitor. Tight binding of C10-AMS blocks fatty acyl substrate entry, and therefore inhibits AasS action. Additionally, this intermediate analog C10-AMS appears to be a mixed-type AasS inhibitor. In summary, our results provide the proof of principle that inhibiting salvage of eFA by AasS reverses the FAS II bypass. This facilitates the development of next-generation anti-bacterial therapeutics, esp. the dual therapy consisting of C10-AMS scaffold derivatives combined with certain FAS II inhibitors.
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Affiliation(s)
- Haomin Huang
- Key Laboratory of Multiple Organ Failure, Ministry of Education; Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Shenghai Chang
- Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tao Cui
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shaanxi, China
| | - Man Huang
- Key Laboratory of Multiple Organ Failure, Ministry of Education; Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jiuxin Qu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Huimin Zhang
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Ting Lu
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Xing Zhang
- Center of Cryo-Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang, China
| | - Chun Zhou
- School of Public Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Youjun Feng
- Key Laboratory of Multiple Organ Failure, Ministry of Education; Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, National Clinical Research Center for Infectious Diseases, The Second Affiliated Hospital of Southern University of Science and Technology, Shenzhen, Guangdong, China
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3
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Boccia F, Iossa D, Leonardi S, Peluso AM, Bertolino L, Patauner F, Palmieri E, Boenzi R, Zampino R, Durante-Mangoni E. Clinical correlates of circulating small dense low-density lipoproteins in acute infective endocarditis. Infection 2024; 52:935-944. [PMID: 38114685 DOI: 10.1007/s15010-023-02139-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/14/2023] [Indexed: 12/21/2023]
Abstract
BACKGROUND AND AIM Infective endocarditis (IE) is a complex thrombo-inflammatory disorder, the pathogenesis of which involves a multifaceted interplay between vascular damage and bacterial virulence factors. This study aimed to assess the prognostic role of small dense low-density lipoprotein (sdLDL) cholesterol in patients with IE and its correlation with various disease-related features. METHODS A cohort of 198 patients with definite IE was included in this study. Clinical, laboratory, and echocardiographic parameters were meticulously analyzed, with a specific focus on comorbidities. sdLDL levels were measured using stored plasma samples obtained upon admission during the acute phase of the disease. RESULTS The median level of sdLDL was 24 mg/dL [with an interquartile range of 17.9-35.2 mg/dL], and this value showed a statistically significant positive correlation with LDL/HDL cholesterol and triglycerides (p < 0.01 for all). Furthermore, a remarkable inverse correlation between C-reactive protein and D-dimer levels was observed (p < 0.0001). Univariate analysis revealed that patients with sdLDL levels ≤ 24 mg/dL had 2.75 times higher odds of in-hospital mortality (95% Confidence Interval:1.08-6.98, p = 0.031). In addition, nonsurvivors had significantly lower median sdLDL levels (19.7 vs. 26.0 mg/dL, p = 0.041). Lower sdLDL levels were also associated with embolic complications, larger vegetation size, and positive blood cultures for Staphylococci (p = 0.019, p = 0.022, and p < 0.001, respectively). CONCLUSIONS Low circulating sdLDL levels in the acute phase of IE were significantly correlated with unfavorable clinical outcomes. These results suggest that the sdLDL level may serve as an important marker of disease severity in IE and may represent a link between vascular damage, embolic complications, and disease progression.
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Affiliation(s)
- Filomena Boccia
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Domenico Iossa
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Napoli, Italy
- Unit of Infectious and Transplant Medicine, A.O.R.N. Ospedali dei Colli-Ospedale Monaldi, Naples, Italy
| | - Silvia Leonardi
- Unit of Clinical Biochemistry, A.O.R.N. Ospedali dei Colli, Naples, Italy
| | - Anna Maria Peluso
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Lorenzo Bertolino
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Fabian Patauner
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Emilio Palmieri
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
| | - Rita Boenzi
- Unit of Clinical Biochemistry, A.O.R.N. Ospedali dei Colli, Naples, Italy
| | - Rosa Zampino
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Napoli, Italy
- Unit of Infectious and Transplant Medicine, A.O.R.N. Ospedali dei Colli-Ospedale Monaldi, Naples, Italy
| | - Emanuele Durante-Mangoni
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Napoli, Italy.
- Unit of Infectious and Transplant Medicine, A.O.R.N. Ospedali dei Colli-Ospedale Monaldi, Naples, Italy.
- Ospedale Monaldi, Piazzale Ettore Ruggieri, 80131, Naples, Italy.
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Saadat N, Aguate F, Nowak AL, Hyer S, Lin AB, Decot H, Koch H, Walker DS, Lydic T, Padmanabhan V, Campos GDL, Misra D, Giurgescu C. Changes in Lipid Profiles with the Progression of Pregnancy in Black Women. J Clin Med 2024; 13:2795. [PMID: 38792337 PMCID: PMC11122055 DOI: 10.3390/jcm13102795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/16/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024] Open
Abstract
Background/Objectives: Lipid metabolism plays an important role in maternal health and fetal development. There is a gap in the knowledge of how lipid metabolism changes during pregnancy for Black women who are at a higher risk of adverse outcomes. We hypothesized that the comprehensive lipidome profiles would show variation across pregnancy indicative of requirements during gestation and fetal development. Methods: Black women were recruited at prenatal clinics. Plasma samples were collected at 8-18 weeks (T1), 22-29 weeks (T2), and 30-36 weeks (T3) of pregnancy. Samples from 64 women who had term births (≥37 weeks gestation) were subjected to "shotgun" Orbitrap mass spectrometry. Mixed-effects models were used to quantify systematic changes and dimensionality reduction models were used to visualize patterns and identify reliable lipid signatures. Results: Total lipids and major lipid classes showed significant increases with the progression of pregnancy. Phospholipids and glycerolipids exhibited a gradual increase from T1 to T2 to T3, while sphingolipids and total sterol lipids displayed a more pronounced increase from T2 to T3. Acylcarnitines, hydroxy acylcarnitines, and Lyso phospholipid levels significantly decreased from T1 to T3. A deviation was that non-esterified fatty acids decreased from T1 to T2 and increased again from T2 to T3, suggestive of a potential role for these lipids during the later stages of pregnancy. The fatty acids showing this trend included key fatty acids-non-esterified Linoleic acid, Arachidonic acid, Alpha-linolenic acid, Eicosapentaenoic acid, Docosapentaenoic acid, and Docosahexaenoic acid. Conclusions: Mapping lipid patterns and identifying lipid signatures would help develop intervention strategies to reduce perinatal health disparities among pregnant Black women.
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Affiliation(s)
- Nadia Saadat
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48019, USA;
| | - Fernando Aguate
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48824, USA
| | | | - Suzanne Hyer
- College of Nursing, University of Central Florida, Orlando, FL 32826, USA
| | - Anna B. Lin
- Molecular Metabolism and Disease Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | - Hannah Decot
- Molecular Metabolism and Disease Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | - Hannah Koch
- Molecular Metabolism and Disease Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | | | - Todd Lydic
- Molecular Metabolism and Disease Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | | | - Gustavo de los Campos
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48824, USA
| | - Dawn Misra
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48824, USA
| | - Carmen Giurgescu
- College of Nursing, University of Central Florida, Orlando, FL 32826, USA
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5
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Raskovic D, Alvarado G, Hines KM, Xu L, Gatto C, Wilkinson BJ, Pokorny A. Growth of Staphylococcus aureus in the presence of oleic acid shifts the glycolipid fatty acid profile and increases resistance to antimicrobial peptides. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.03.592415. [PMID: 38746422 PMCID: PMC11092785 DOI: 10.1101/2024.05.03.592415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Staphylococcus aureus readily adapts to various environments and quickly develops antibiotic resistance, which has led to an increase in multidrug-resistant infections. Hence, S. aureus presents a significant global health issue and its adaptations to the host environment are crucial for understanding pathogenesis and antibiotic susceptibility. When S. aureus is grown conventionally, its membrane lipids contain a mix of branched-chain and straight-chain saturated fatty acids. However, when unsaturated fatty acids are present in the growth medium, they become a major part of the total fatty acid composition. This study explores the biophysical effects of incorporating straight-chain unsaturated fatty acids into S. aureus membrane lipids. Membrane preparations from cultures supplemented with oleic acid showed more complex differential scanning calorimetry scans than those grown in tryptic soy broth alone. When grown in the presence of oleic acid, the cultures exhibited a transition significantly above the growth temperature, attributed to the presence of glycolipids with long-chain fatty acids causing acyl chain packing frustration within the bilayer. Functional aspects of the membrane were assessed by studying the kinetics of dye release from unilamellar vesicles induced by the antimicrobial peptide mastoparan X. Dye release was slower from liposomes prepared from cells grown in oleic acid-supplemented cultures, suggesting that changes in membrane lipid composition and biophysics protect the cell membrane against peptide-induced lysis. These findings underscore the intricate relationship between the growth environment, membrane lipid composition, and the physical properties of the bacterial membrane, which should be considered when developing new strategies against S. aureus infections.
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Affiliation(s)
- Djuro Raskovic
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
| | - Gloria Alvarado
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Kelly M Hines
- Department of Chemistry, University of Georgia, Athens, Georgia, United States of America
| | - Libin Xu
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, United States of America
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Brian J Wilkinson
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina, United States of America
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6
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Ahmad Z, Singh S, Lee TJ, Sharma A, Lydic TA, Giri S, Kumar A. Untargeted and temporal analysis of retinal lipidome in bacterial endophthalmitis. Prostaglandins Other Lipid Mediat 2024; 171:106806. [PMID: 38185280 PMCID: PMC10939753 DOI: 10.1016/j.prostaglandins.2023.106806] [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: 06/09/2023] [Revised: 11/22/2023] [Accepted: 12/26/2023] [Indexed: 01/09/2024]
Abstract
Bacterial endophthalmitis is a blinding infectious disease typically acquired during ocular surgery. We previously reported significant alterations in retinal metabolism during Staphylococcus (S) aureus endophthalmitis. However, the changes in retinal lipid composition during endophthalmitis are unknown. Here, using a mouse model of S. aureus endophthalmitis and an untargeted lipidomic approach, we comprehensively analyzed temporal alterations in total lipids and oxylipin in retina. Our data showed a time-dependent increase in the levels of lipid classes, sphingolipids, glycerolipids, sterols, and non-esterified fatty acids, whereas levels of phospholipids decreased. Among lipid subclasses, phosphatidylcholine decreased over time. The oxylipin analysis revealed increased prostaglandin-E2, hydroxyeicosatetraenoic acids, docosahexaenoic acid, eicosapentaenoic acid, and α-linolenic acid. In-vitro studies using mouse bone marrow-derived macrophages showed increased lipid droplets and lipid-peroxide formation in response to S. aureus infection. Collectively, these findings suggest that S. aureus-infection alters the retinal lipid profile, which may contribute to the pathogenesis of bacterial endophthalmitis.
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Affiliation(s)
- Zeeshan Ahmad
- Department of Ophthalmology, Visual and Anatomical Sciences/ Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI, USA
| | - Sukhvinder Singh
- Department of Ophthalmology, Visual and Anatomical Sciences/ Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI, USA
| | - Tae Jin Lee
- Augusta University, Augusta, GA, USA. 4 Department of Ophthalmology, Augusta University, Augusta, GA, USA
| | - Ashok Sharma
- Augusta University, Augusta, GA, USA. 4 Department of Ophthalmology, Augusta University, Augusta, GA, USA
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Shailendra Giri
- Department of Neurology, Henry Ford Health System, Detroit, MI, USA
| | - Ashok Kumar
- Department of Ophthalmology, Visual and Anatomical Sciences/ Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI, USA; Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, MI, USA.
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7
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Myers MJ, Xu Z, Ryan BJ, DeMars ZR, Ridder MJ, Johnson DK, Krute CN, Flynn TS, Kashipathy MM, Battaile KP, Schnicker N, Lovell S, Freudenthal BD, Bose JL. Molecular basis for the activation of the Fatty Acid Kinase complex of Staphylococcus aureus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.19.585040. [PMID: 38562735 PMCID: PMC10983944 DOI: 10.1101/2024.03.19.585040] [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
Gram-positive bacteria utilize a Fatty Acid Kinase (FAK) complex to harvest fatty acids from the environment. The complex, consisting of the fatty acid kinase, FakA, and an acyl carrier protein, FakB, is known to impact virulence and disease outcomes. However, FAK's structure and enzymatic mechanism remain poorly understood. Here, we used a combination of modeling, biochemical, and cell-based approaches to establish critical details of FAK activity. Solved structures of the apo and ligand-bound FakA kinase domain captured the protein state through ATP hydrolysis. Additionally, targeted mutagenesis of an understudied FakA Middle domain identified critical residues within a metal-binding pocket that contribute to FakA dimer stability and protein function. Regarding the complex, we demonstrated nanomolar affinity between FakA and FakB and generated computational models of the complex's quaternary structure. Together, these data provide critical insight into the structure and function of the FAK complex which is essential for understanding its mechanism.
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8
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Barbarek SC, Shah R, Paul S, Alvarado G, Appala K, Henderson EC, Strandquist ET, Pokorny A, Singh VK, Gatto C, Dahl JU, Hines KM, Wilkinson BJ. Lipidomics of homeoviscous adaptation to low temperatures in Staphylococcus aureus utilizing exogenous straight-chain unsaturated fatty acids over biosynthesized endogenous branched-chain fatty acids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.02.578686. [PMID: 38352554 PMCID: PMC10862916 DOI: 10.1101/2024.02.02.578686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
It is well established that Staphylococcus aureus can incorporate exogenous straight-chain unsaturated fatty acids (SCUFAs) into membrane phospho- and glyco-lipids from various sources in supplemented culture media, and when growing in vivo in an infection. Given the enhancement of membrane fluidity when oleic acid (C18:1Δ9) is incorporated into lipids, we were prompted to examine the effect of medium supplementation with C18:1Δ9 on growth at low temperatures. C18:1Δ9 supported the growth of a cold-sensitive, branched-chain fatty acid (BCFA)-deficient mutant at 12°C. Interestingly, we found similar results in the BCFA-sufficient parental strain. We show that incorporation of C18:1Δ9 and its elongation product C20:1Δ9 into membrane lipids was required for growth stimulation and relied on a functional FakAB incorporation system. Lipidomics analysis of the phosphatidylglycerol (PG) and diglycosyldiacylglycerol (DGDG) lipid classes revealed major impacts of C18:1Δ9 and temperature on lipid species. Growth at 12°C in the presence of C18:1Δ9 also led to increased production of the carotenoid pigment staphyloxanthin; however, this was not an obligatory requirement for cold adaptation. Enhancement of growth by C18:1Δ9 is an example of homeoviscous adaptation to low temperatures utilizing an exogenous fatty acid. This may be significant in the growth of S. aureus at low temperatures in foods that commonly contain C18:1Δ9 and other SCUFAs in various forms.
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Affiliation(s)
| | - Ritika Shah
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Sharanya Paul
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Gloria Alvarado
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Keerthi Appala
- Department of Chemistry, University of Georgia, Athens, GA
| | - Emma C. Henderson
- School of Biological Sciences, Illinois State University, Normal, IL
| | | | - Antje Pokorny
- Department of Chemistry and Biochemistry, University of North Carolina-Wilmington, Wilmington, NC
| | - Vineet K. Singh
- Department of Microbiology and Immunology, Kirksville College of Osteopathic Medicine, A. T. Still University of Health Sciences, Kirksville, MO
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Jan-Ulrik Dahl
- School of Biological Sciences, Illinois State University, Normal, IL
| | - Kelly M. Hines
- Department of Chemistry, University of Georgia, Athens, GA
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9
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Pruitt EL, Zhang R, Ross DH, Ashford NK, Chen X, Alonzo F, Bush MF, Werth BJ, Xu L. Elucidating the impact of bacterial lipases, human serum albumin, and FASII inhibition on the utilization of exogenous fatty acids by Staphylococcus aureus. mSphere 2023; 8:e0036823. [PMID: 38014966 PMCID: PMC10732024 DOI: 10.1128/msphere.00368-23] [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: 07/06/2023] [Accepted: 10/26/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Incorporation of host-derived exogenous fatty acids (eFAs), particularly unsaturated fatty acids (UFAs), by Staphylococcus aureus could affect the bacterial membrane fluidity and susceptibility to antimicrobials. In this work, we found that glycerol ester hydrolase (Geh) is the primary lipase hydrolyzing cholesteryl esters and, to a lesser extent, triglycerides and that human serum albumin (HSA) could serve as a buffer of eFAs, where low levels of HSA facilitate the utilization of eFAs but high levels of HSA inhibit it. The fact that the type II fatty acid synthesis (FASII) inhibitor, AFN-1252, leads to an increase in UFA content even in the absence of eFA suggests that membrane property modulation is part of its mechanism of action. Thus, Geh and/or the FASII system look to be promising targets to enhance S. aureus killing in a host environment by restricting eFA utilization or modulating membrane properties, respectively.
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Affiliation(s)
- Emily L. Pruitt
- Department of Chemistry, University of Washington, Seattle, Washington, USA
| | - Rutan Zhang
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | - Dylan H. Ross
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
| | | | - Xi Chen
- Department of Microbiology and Immunology, Loyola University Chicago-Stritch School of Medicine, Maywood, Illinois, USA
| | - Francis Alonzo
- Department of Microbiology and Immunology, Loyola University Chicago-Stritch School of Medicine, Maywood, Illinois, USA
| | - Matthew F. Bush
- Department of Chemistry, University of Washington, Seattle, Washington, USA
| | - Brian J. Werth
- Department of Pharmacy, University of Washington, Seattle, Washington, USA
| | - Libin Xu
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington, USA
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10
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Jiang JH, Cameron DR, Nethercott C, Aires-de-Sousa M, Peleg AY. Virulence attributes of successful methicillin-resistant Staphylococcus aureus lineages. Clin Microbiol Rev 2023; 36:e0014822. [PMID: 37982596 PMCID: PMC10732075 DOI: 10.1128/cmr.00148-22] [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] [Indexed: 11/21/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of severe and often fatal infections. MRSA epidemics have occurred in waves, whereby a previously successful lineage has been replaced by a more fit and better adapted lineage. Selection pressures in both hospital and community settings are not uniform across the globe, which has resulted in geographically distinct epidemiology. This review focuses on the mechanisms that trigger the establishment and maintenance of current, dominant MRSA lineages across the globe. While the important role of antibiotic resistance will be mentioned throughout, factors which influence the capacity of S. aureus to colonize and cause disease within a host will be the primary focus of this review. We show that while MRSA possesses a diverse arsenal of toxins including alpha-toxin, the success of a lineage involves more than just producing toxins that damage the host. Success is often attributed to the acquisition or loss of genetic elements involved in colonization and niche adaptation such as the arginine catabolic mobile element, as well as the activity of regulatory systems, and shift metabolism accordingly (e.g., the accessory genome regulator, agr). Understanding exactly how specific MRSA clones cause prolonged epidemics may reveal targets for therapies, whereby both core (e.g., the alpha toxin) and acquired virulence factors (e.g., the Panton-Valentine leukocidin) may be nullified using anti-virulence strategies.
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Affiliation(s)
- Jhih-Hang Jiang
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - David R. Cameron
- Department of Biomedical Research, University of Bern, Bern, Switzerland
| | - Cara Nethercott
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Marta Aires-de-Sousa
- Laboratory of Molecular Genetics, Institutode Tecnologia Químicae Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Oeiras, Portugal
- Escola Superior de Saúde da Cruz Vermelha Portuguesa-Lisboa (ESSCVP-Lisboa), Lisbon, Portugal
| | - Anton Y. Peleg
- Department of Microbiology, Infection Program, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Centre to Impact Antimicrobial Resistance, Monash University, Clayton, Melbourne, Victoria, Australia
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11
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Yang ZH, Gorusupudi A, Lydic TA, Mondal AK, Sato S, Yamazaki I, Yamaguchi H, Tang J, Rojulpote KV, Lin AB, Decot H, Koch H, Brock DC, Arunkumar R, Shi ZD, Yu ZX, Pryor M, Kun JF, Swenson RE, Swaroop A, Bernstein PS, Remaley AT. Dietary fish oil enriched in very-long-chain polyunsaturated fatty acid reduces cardiometabolic risk factors and improves retinal function. iScience 2023; 26:108411. [PMID: 38047069 PMCID: PMC10692724 DOI: 10.1016/j.isci.2023.108411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 08/31/2023] [Accepted: 11/03/2023] [Indexed: 12/05/2023] Open
Abstract
Very-long-chain polyunsaturated fatty acids (VLCPUFAs; C24-38) constitute a unique class of PUFA that have important biological roles, but the lack of a suitable dietary source has limited research in this field. We produced an n-3 C24-28-rich VLCPUFA-oil concentrated from fish oil to study its bioavailability and physiological functions in C57BL/6J mice. The serum and retinal C24:5 levels increased significantly compared to control after a single-dose gavage, and VLCPUFAs were incorporated into the liver, brain, and eyes after 8-week supplementation. Dietary VLCPUFAs resulted in favorable cardiometabolic changes, and improved electroretinography responses and visual performance. VLCPUFA supplementation changed the expression of genes involved in PPAR signaling pathways. Further in vitro studies demonstrated that the VLCPUFA-oil and chemically synthesized C24:5 are potent agonists for PPARs. The multiple potential beneficial effects of fish oil-derived VLCPUFAs on cardiometabolic risk and eye health in mice support future efforts to develop VLCPUFA-oil into a supplemental therapy.
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Affiliation(s)
- Zhi-Hong Yang
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Aruna Gorusupudi
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, Salt Lake City, UT 84132, USA
| | - Todd A. Lydic
- Department of Physiology, Collaborative Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | - Anupam K. Mondal
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, NIH, Bethesda, MD 20892, USA
| | - Seizo Sato
- Central Research Laboratory, Nissui Corporation, 1-32-3 Nanakuni, Hachioji, Tokyo 192-0991, Japan
| | - Isao Yamazaki
- Central Research Laboratory, Nissui Corporation, 1-32-3 Nanakuni, Hachioji, Tokyo 192-0991, Japan
| | - Hideaki Yamaguchi
- Central Research Laboratory, Nissui Corporation, 1-32-3 Nanakuni, Hachioji, Tokyo 192-0991, Japan
| | - Jingrong Tang
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Krishna Vamsi Rojulpote
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Anna B. Lin
- Department of Physiology, Collaborative Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | - Hannah Decot
- Department of Physiology, Collaborative Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | - Hannah Koch
- Department of Physiology, Collaborative Mass Spectrometry Core, Michigan State University, East Lansing, MI 48824, USA
| | - Daniel C. Brock
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, NIH, Bethesda, MD 20892, USA
| | - Ranganathan Arunkumar
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, Salt Lake City, UT 84132, USA
| | - Zhen-Dan Shi
- Chemistry and Synthesis Center, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Zu-Xi Yu
- Pathology Core, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Milton Pryor
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Julia F. Kun
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Rolf E. Swenson
- Chemistry and Synthesis Center, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, NIH, Bethesda, MD 20892, USA
| | - Paul S. Bernstein
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, Salt Lake City, UT 84132, USA
| | - Alan T. Remaley
- Lipoprotein Metabolism Section, Translational Vascular Medicine Branch, National Heart, Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
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12
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Zelows MM, Cady C, Dharanipragada N, Mead AE, Kipp ZA, Bates EA, Varadharajan V, Banerjee R, Park SH, Shelman NR, Clarke HA, Hawkinson TR, Medina T, Sun RC, Lydic TA, Hinds TD, Brown JM, Softic S, Graf GA, Helsley RN. Loss of carnitine palmitoyltransferase 1a reduces docosahexaenoic acid-containing phospholipids and drives sexually dimorphic liver disease in mice. Mol Metab 2023; 78:101815. [PMID: 37797918 PMCID: PMC10568566 DOI: 10.1016/j.molmet.2023.101815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/22/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND AND AIMS Genome and epigenome wide association studies identified variants in carnitine palmitoyltransferase 1a (CPT1a) that associate with lipid traits. The goal of this study was to determine the role of liver-specific CPT1a on hepatic lipid metabolism. APPROACH AND RESULTS Male and female liver-specific knockout (LKO) and littermate controls were placed on a low-fat or high-fat diet (60% kcal fat) for 15 weeks. Mice were necropsied after a 16 h fast, and tissues were collected for lipidomics, matrix-assisted laser desorption ionization mass spectrometry imaging, kinome analysis, RNA-sequencing, and protein expression by immunoblotting. Female LKO mice had increased serum alanine aminotransferase levels which were associated with greater deposition of hepatic lipids, while male mice were not affected by CPT1a deletion relative to male control mice. Mice with CPT1a deletion had reductions in DHA-containing phospholipids at the expense of monounsaturated fatty acids (MUFA)-containing phospholipids in whole liver and at the level of the lipid droplet (LD). Male and female LKO mice increased RNA levels of genes involved in LD lipolysis (Plin2, Cidec, G0S2) and in polyunsaturated fatty acid metabolism (Elovl5, Fads1, Elovl2), while only female LKO mice increased genes involved in inflammation (Ly6d, Mmp12, Cxcl2). Kinase profiling showed decreased protein kinase A activity, which coincided with increased PLIN2, PLIN5, and G0S2 protein levels and decreased triglyceride hydrolysis in LKO mice. CONCLUSIONS Liver-specific deletion of CPT1a promotes sexually dimorphic steatotic liver disease (SLD) in mice, and here we have identified new mechanisms by which females are protected from HFD-induced liver injury.
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Affiliation(s)
- Mikala M Zelows
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, USA
| | - Corissa Cady
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Nikitha Dharanipragada
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Anna E Mead
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Zachary A Kipp
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Evelyn A Bates
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | - Rakhee Banerjee
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Se-Hyung Park
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Department of Pediatrics and Gastroenterology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Nathan R Shelman
- Department of Pathology and Laboratory Medicine, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Harrison A Clarke
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Tara R Hawkinson
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Terrymar Medina
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ramon C Sun
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, FL, USA; Center for Advanced Spatial Biomolecule Research, University of Florida College of Medicine, Gainesville, FL, USA
| | - Todd A Lydic
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Terry D Hinds
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Barnstable Brown Diabetes Center, University of Kentucky College of Medicine, Lexington, KY, USA; Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA
| | - J Mark Brown
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Samir Softic
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Department of Pediatrics and Gastroenterology, University of Kentucky College of Medicine, Lexington, KY, USA
| | - Gregory A Graf
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA
| | - Robert N Helsley
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA; Barnstable Brown Diabetes Center, University of Kentucky College of Medicine, Lexington, KY, USA; Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA; Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA; Department of Internal Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Kentucky College of Medicine, Lexington, KY, USA.
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13
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Zelows MM, Cady C, Dharanipragada N, Mead AE, Kipp ZA, Bates EA, Varadharajan V, Banerjee R, Park SH, Shelman NR, Clarke HA, Hawkinson TR, Medina T, Sun RC, Lydic TA, Hinds TD, Brown JM, Softic S, Graf GA, Helsley RN. Loss of Carnitine Palmitoyltransferase 1a Reduces Docosahexaenoic Acid-Containing Phospholipids and Drives Sexually Dimorphic Liver Disease in Mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553705. [PMID: 37645721 PMCID: PMC10462091 DOI: 10.1101/2023.08.17.553705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Background and Aims Genome and epigenome wide association studies identified variants in carnitine palmitoyltransferase 1a (CPT1a) that associate with lipid traits. The goal of this study was to determine the impact by which liver-specific CPT1a deletion impacts hepatic lipid metabolism. Approach and Results Six-to-eight-week old male and female liver-specific knockout (LKO) and littermate controls were placed on a low-fat or high-fat diet (HFD; 60% kcal fat) for 15 weeks. Mice were necropsied after a 16 hour fast, and tissues were collected for lipidomics, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), kinome analysis, RNA-sequencing, and protein expression by immunoblotting. Female LKO mice had increased serum alanine aminotransferase (ALT) levels which were associated with greater deposition of hepatic lipids, while male mice were not affected by CPT1a deletion relative to male control mice. Mice with CPT1a deletion had reductions in DHA-containing phospholipids at the expense of monounsaturated fatty acids (MUFA)-containing phospholipids in both whole liver and at the level of the lipid droplet (LD). Male and female LKO mice increased RNA levels of genes involved in LD lipolysis ( Plin2 , Cidec , G0S2 ) and in polyunsaturated fatty acid (PUFA) metabolism ( Elovl5, Fads1, Elovl2 ), while only female LKO mice increased genes involved in inflammation ( Ly6d, Mmp12, Cxcl2 ). Kinase profiling showed decreased protein kinase A (PKA) activity, which coincided with increased PLIN2, PLIN5, and G0S2 protein levels and decreased triglyceride hydrolysis in LKO mice. Conclusions Liver-specific deletion of CPT1a promotes sexually dimorphic steatotic liver disease (SLD) in mice, and here we have identified new mechanisms by which females are protected from HFD-induced liver injury. Graphical Summary
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14
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Subramanian C, Frank MW, Yun MK, Rock CO. The Phospholipase A1 Activity of Glycerol Ester Hydrolase (Geh) Is Responsible for Extracellular 2-12( S)-Methyltetradecanoyl-Lysophosphatidylglycerol Production in Staphylococcus aureus. mSphere 2023; 8:e0003123. [PMID: 36976028 PMCID: PMC10117073 DOI: 10.1128/msphere.00031-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/07/2023] [Indexed: 03/29/2023] Open
Abstract
Phosphatidylglycerol (PG) is the major membrane phospholipid of Staphylococcus aureus and predominately consists of molecular species with ≥16-carbon acyl chains in the 1-position and anteiso 12(S)-methyltetradecaonate (a15) esterified at the 2-position. The analysis of the growth media for PG-derived products shows S. aureus releases essentially pure 2-12(S)-methyltetradecanoyl-sn-glycero-3-phospho-1'-sn-glycerol (a15:0-LPG) derived from the hydrolysis of the 1-position of PG into the environment. The cellular lysophosphatidylglycerol (LPG) pool is dominated by a15-LPG but also consists of ≥16-LPG species arising from the removal of the 2-position. Mass tracing experiments confirmed a15-LPG was derived from isoleucine metabolism. A screen of candidate secreted lipase knockout strains pinpointed glycerol ester hydrolase (geh) as the gene required for generating extracellular a15-LPG, and complementation of a Δgeh strain with a Geh expression plasmid restored extracellular a15-LPG formation. Orlistat, a covalent inhibitor of Geh, also attenuated extracellular a15-LPG accumulation. Purified Geh hydrolyzed the 1-position acyl chain of PG and generated only a15-LPG from a S. aureus lipid mixture. The Geh product was 2-a15-LPG, which spontaneously isomerizes with time to a mixture of 1- and 2-a15-LPG. Docking PG in the Geh active site provides a structural rationale for the positional specificity of Geh. These data demonstrate a physiological role for Geh phospholipase A1 activity in S. aureus membrane phospholipid turnover. IMPORTANCE Glycerol ester hydrolase, Geh, is an abundant secreted lipase whose expression is controlled by the accessory gene regulator (Agr) quorum-sensing signal transduction pathway. Geh is thought to have a role in virulence based on its ability to hydrolyze host lipids at the infection site to provide fatty acids for membrane biogenesis and substrates for oleate hydratase, and Geh inhibits immune cell activation by hydrolyzing lipoprotein glycerol esters. The discovery that Geh is the major contributor to the formation and release of a15-LPG reveals an unappreciated physiological role for Geh acting as a phospholipase A1 in the degradation of S. aureus membrane phosphatidylglycerol. The role(s) for extracellular a15-LPG in S. aureus biology remain to be elucidated.
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Affiliation(s)
- Chitra Subramanian
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Matthew W. Frank
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - My-Kyung Yun
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
| | - Charles O. Rock
- Department of Infectious Diseases, St. Jude Children’s Research Hospital, Memphis, Tennessee, USA
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15
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Ayala DI, Grum DS, Evans NP, Russo KN, Kimminau EA, Trible BR, Lahoti MM, Novak CL, Karnezos TP. Identification and characterization of the causative agents of Focal Ulcerative Dermatitis in commercial laying hens. Front Vet Sci 2023; 10:1110573. [PMID: 36846268 PMCID: PMC9945107 DOI: 10.3389/fvets.2023.1110573] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/13/2023] [Indexed: 02/10/2023] Open
Abstract
Focal Ulcerative Dermatitis (FUDS) is an emerging dermatological disease that affects cage-free laying flocks, it is characterized by the development of a lesion on the dorsum of the birds; FUDS is sporadic in nature and can result in a drop in egg production and up to 50% of cumulative mortality. A total of two cage-free flocks (flock 1: no history of FUDS; flock 2: birds affected with FUDS) from a commercial laying hen operation in the mid-west U.S. were sampled in this study. The microbial composition of skin, cloacal, cecal, and ileal samples from each bird was characterized through next generation sequencing (NGS). Results identified Staphylococcus aureus and Staphylococcus agnetis as the potential causative agents of FUDS, being the most predominant in FUDS positive birds. These results were confirmed by plating, with both staphylococci as the only pathogens isolated from lesions of FUDS positive birds. A total of 68 confirmed Staphylococcus isolates from skin and environmental samples were further analyzed by whole genome sequencing (WGS) for the presence of antimicrobial resistance (AMR) genes and virulence factors that could have contributed to the development of FUDS. Forty-four-point one-two percent of the isolates had between one and four acquired AMR genes encoding for macrolides, lincosamides, spectrogramines, and beta-lactams resistance. Six classes of virulence factors associated with adherence, enzyme, immune evasion, secretion system, toxin, and iron uptake were identified. The antimicrobial effect of 4 proprietary Bacillus Direct Fed Microbial (DFM) combinations was evaluated against the Staphylococcus aureus and Staphylococcus agnetis isolates, by agar well-diffusion (AWD) assay and competitive exclusion (CE) on broth culture. Through this antimicrobial screening, a particular two-strain combination of Bacillus pumilus was identified as the most effective inhibitor of both staphylococci. A customized Bacillus pumilus product is being used at different farms with history of FUDS resulting in the successful inhibition of both Staphylococcus aureus and Staphylococcus agnetis, decreasing FUDS mortalities, and improving harvestable eggs.
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Affiliation(s)
| | - Daniel S. Grum
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
| | - Nicholas P. Evans
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
| | - Kay N. Russo
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
| | - Emily A. Kimminau
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
| | - Benjamin R. Trible
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
| | - Manohar M. Lahoti
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
| | - Curtis L. Novak
- Purina Animal Nutrition Center, Land O' Lakes, Gray Summit, MO, United States
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16
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Shi Y, Zang N, Lou N, Xu Y, Sun J, Huang M, Zhang H, Lu H, Zhou C, Feng Y. Structure and mechanism for streptococcal fatty acid kinase (Fak) system dedicated to host fatty acid scavenging. SCIENCE ADVANCES 2022; 8:eabq3944. [PMID: 36054360 PMCID: PMC10848957 DOI: 10.1126/sciadv.abq3944] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Staphylococcus and Streptococcus, two groups of major human pathogens, are equipped with a fatty acid kinase (Fak) machinery to scavenge host fatty acids. The Fak complex is contains an ATP-binding subunit FakA, which interacts with varied FakB isoforms, and synthesizes acyl-phosphate from extracellular fatty acids. However, how FakA recognizes its FakB partners and then activates different fatty acids is poorly understood. Here, we systematically describe the Fak system from the zoonotic pathogen, Streptococcus suis. The crystal structure of SsFakA complexed with SsFakB2 was determined at 2.6 Å resolution. An in vitro system of Fak-PlsX (phosphate: acyl-ACP transacylase) was developed to track acyl-phosphate intermediate and its final product acyl-ACP. Structure-guided mutagenesis enabled us to characterize a mechanism for streptococcal FakA working with FakB partners engaged in host fatty acid scavenging. These findings offer a comprehensive description of the Fak kinase machinery, thus advancing the discovery of attractive targets against deadly infections with Streptococcus.
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Affiliation(s)
- Yu Shi
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Ning Zang
- Department of Toxicology, School of Public Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Ningjie Lou
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Yongchang Xu
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jingdu Sun
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Man Huang
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Huimin Zhang
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Huijie Lu
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Chun Zhou
- Department of Toxicology, School of Public Health, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Youjun Feng
- Departments of Microbiology and General Intensive Care Unit of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Transcriptomic and Metabolomic Analysis of a Fusidic Acid-Selected fusA Mutant of Staphylococcus aureus. Antibiotics (Basel) 2022; 11:antibiotics11081051. [PMID: 36009920 PMCID: PMC9405211 DOI: 10.3390/antibiotics11081051] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022] Open
Abstract
Physiological experimentation, transcriptomics, and metabolomics were engaged to compare a fusidic acid-resistant Staphylococcus aureus mutant SH10001st-2 to its parent strain SH1000. SH10001st-2 harbored a mutation (H457Y) in the gene fusA which encodes the fusidic acid target, elongation factor G, as well as mutations in a putative phage gene of unknown function. SH10001st-2 grew slower than SH1000 at three temperatures and had reduced coagulase activity, two indicators of the fitness penalty reported for fusA-mediated fusidic acid- resistance in the absence of compensatory mutations. Despite the difference in growth rates, the levels of O2 consumption and CO2 production were comparable. Transcriptomic profiling revealed 326 genes were upregulated and 287 were downregulated in SH10001st-2 compared to SH1000. Cell envelope and transport and binding protein genes were the predominant functional categories of both upregulated and downregulated genes in SH10001st-2. Genes of virulence regulators, notably the agr and kdp systems, were highly upregulated as were genes encoding capsule production. Contrary to what is expected of mid-exponential phase cells, genes encoding secreted virulence factors were generally upregulated while those for adhesion-associated virulence factors were downregulated in SH10001st-2. Metabolomic analysis showed an overall increase in metabolite pools in SH10001st-2 compared to SH1000, mostly for amino acids and sugars. Slowed growth and metabolite accumulation may be byproducts of fusA mutation-mediated protein synthesis impairment, but the overall results indicate that SH10001st-2 is compensating for the H457Y fitness penalty by repurposing its virulence machinery, in conjunction with increasing metabolite uptake capacity, in order to increase nutrient acquisition.
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18
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Stephens AC, Richardson AR. Recent developments in our understanding of the physiology and nitric oxide-resistance of Staphylococcus aureus. Adv Microb Physiol 2022; 81:111-135. [PMID: 36167441 DOI: 10.1016/bs.ampbs.2022.06.003] [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: 01/27/2023]
Abstract
Staphylococcus aureus is an important human pathogen causing a wide range of disease presentations. It harbors a vast array of virulence factors and drug-resistance determinants. All of these factors are coordinately regulated by a hand full of key transcriptional regulators. The regulation and expression of these factors are tightly intertwined with the metabolic state of the cell. Furthermore, alterations in central metabolism are also key to the ability of S. aureus to resist clearance by the host innate immune response, including nitric oxide (NO·) production. Given the fact that central metabolism directly influences virulence, drug resistance and immune tolerance in S. aureus, a better understanding of the metabolic capabilities of this pathogen is critical. This work highlights some of the major findings within the last five years surrounding S. aureus central metabolism, both organic and inorganic. These are also put in the context of the unique NO·-resistance associated with this pathogen as well as their contributions to virulence. The more we understand the intersection between central metabolism and virulence capabilities in S. aureus, the better the chances of developing novel therapeutics so desperately needed to treat this pathogen.
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Affiliation(s)
- Amelia C Stephens
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, United States
| | - Anthony R Richardson
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, United States.
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Nutritional Interactions between Bacterial Species Colonising the Human Nasal Cavity: Current Knowledge and Future Prospects. Metabolites 2022; 12:metabo12060489. [PMID: 35736422 PMCID: PMC9229137 DOI: 10.3390/metabo12060489] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/16/2022] [Accepted: 05/25/2022] [Indexed: 12/10/2022] Open
Abstract
The human nasal microbiome can be a reservoir for several pathogens, including Staphylococcus aureus. However, certain harmless nasal commensals can interfere with pathogen colonisation, an ability that could be exploited to prevent infection. Although attractive as a prophylactic strategy, manipulation of nasal microbiomes to prevent pathogen colonisation requires a better understanding of the molecular mechanisms of interaction that occur between nasal commensals as well as between commensals and pathogens. Our knowledge concerning the mechanisms of pathogen exclusion and how stable community structures are established is patchy and incomplete. Nutrients are scarce in nasal cavities, which makes competitive or mutualistic traits in nutrient acquisition very likely. In this review, we focus on nutritional interactions that have been shown to or might occur between nasal microbiome members. We summarise concepts of nutrient release from complex host molecules and host cells as well as of intracommunity exchange of energy-rich fermentation products and siderophores. Finally, we discuss the potential of genome-based metabolic models to predict complex nutritional interactions between members of the nasal microbiome.
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20
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Agaronyan K, Sharma L, Vaidyanathan B, Glenn K, Yu S, Annicelli C, Wiggen TD, Penningroth MR, Hunter RC, Dela Cruz CS, Medzhitov R. Tissue remodeling by an opportunistic pathogen triggers allergic inflammation. Immunity 2022; 55:895-911.e10. [PMID: 35483356 PMCID: PMC9123649 DOI: 10.1016/j.immuni.2022.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 01/04/2022] [Accepted: 04/04/2022] [Indexed: 01/01/2023]
Abstract
Different effector arms of the immune system are optimized to protect from different classes of pathogens. In some cases, pathogens manipulate the host immune system to promote the wrong type of effector response-a phenomenon known as immune deviation. Typically, immune deviation helps pathogens to avoid destructive immune responses. Here, we report on a type of immune deviation whereby an opportunistic pathogen, Pseudomonas aeruginosa (P. aeruginosa), induces the type 2 immune response resulting in mucin production that is used as an energy source by the pathogen. Specifically, P. aeruginosa-secreted toxin, LasB, processed and activated epithelial amphiregulin to induce type 2 inflammation and mucin production. This "niche remodeling" by P. aeruginosa promoted colonization and, as a by-product, allergic sensitization. Our study thus reveals a type of bacterial immune deviation by increasing nutrient supply. It also uncovers a mechanism of allergic sensitization by a bacterial virulence factor.
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Affiliation(s)
- Karen Agaronyan
- Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Lokesh Sharma
- Department of Internal Medicine, Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT 06520, USA
| | - Bharat Vaidyanathan
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Keith Glenn
- Department of Internal Medicine, Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT 06520, USA
| | - Shuang Yu
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Charles Annicelli
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Talia D Wiggen
- Department of Microbiology & Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Mitchell R Penningroth
- Department of Microbiology & Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Ryan C Hunter
- Department of Microbiology & Immunology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
| | - Charles S Dela Cruz
- Department of Internal Medicine, Pulmonary, Critical Care and Sleep Medicine, Yale School of Medicine, New Haven, CT 06520, USA
| | - Ruslan Medzhitov
- Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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21
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Gaurivaud P, Tardy F. The Mycoplasma spp. ‘Releasome’: A New Concept for a Long-Known Phenomenon. Front Microbiol 2022; 13:853440. [PMID: 35495700 PMCID: PMC9051441 DOI: 10.3389/fmicb.2022.853440] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
The bacterial secretome comprises polypeptides expressed at the cell surface or released into the extracellular environment as well as the corresponding secretion machineries. Despite their reduced coding capacities, Mycoplasma spp. are able to produce and release several components into their environment, including polypeptides, exopolysaccharides and extracellular vesicles. Technical difficulties in purifying these elements from the complex broth media used to grow mycoplasmas have recently been overcome by optimizing growth conditions and switching to chemically defined culture media. However, the secretion pathways responsible for the release of these structurally varied elements are still poorly described in mycoplasmas. We propose the use of the term ‘releasome,’ instead of secretome, to refer to molecules released by mycoplasmas into their environment. The aim of this review is to more precisely delineate the elements that should be considered part of the mycoplasmal releasome and their role in the interplay of mycoplasmas with host cells and tissues.
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22
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Abstract
Staphylococcus aureus is an important pathogen that relies on a variety of mechanisms to evade and counteract the immune system. We show that S. aureus uses oleate hydratase (OhyA) to convert host cis-9 unsaturated fatty acids to their 10-hydroxy derivatives in human serum and at the infection site in a mouse neutropenic thigh model. Wild-type and ΔohyA strains were equally infective in the neutropenic thigh model, but recovery of the ΔohyA strain was 2 orders of magnitude lower in the immunocompetent skin infection model. Despite the lower bacterial abundance at the infection site, the levels of interleukin 6 (IL-6), monocyte chemoattractant protein 1 (MCP-1), IL-1β, and tumor necrosis factor alpha (TNF-α) elicited by the ΔohyA strain were as robust as those of either the wild-type or the complemented strain, indicating that the immune system was more highly activated by the ΔohyA strain. Thus, OhyA functions to promote S. aureus virulence. IMPORTANCE The oleate hydratase protein family was discovered in commensal bacteria that utilize host unsaturated fatty acids as the substrates to produce a spectrum of hydroxylated products. These hydroxy fatty acids are thought to act as signaling molecules that suppress the inflammatory response to create a more tolerant environment for the microbiome. S. aureus is a significant human pathogen, and defining the mechanisms used to evade the immune response is critical to understanding pathogenesis. S. aureus expresses an OhyA that produces at least three 10-hydroxy fatty acids from host unsaturated fatty acids at the infection site, and an S. aureus strain lacking the ohyA gene has compromised virulence in an immunocompetent infection model. These data suggest that OhyA plays a role in immune modulation in S. aureus pathogenesis similar to that in commensal bacteria.
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23
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The cell envelope of Staphylococcus aureus selectively controls the sorting of virulence factors. Nat Commun 2021; 12:6193. [PMID: 34702812 PMCID: PMC8548510 DOI: 10.1038/s41467-021-26517-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus bi-component pore-forming leukocidins are secreted toxins that directly target and lyse immune cells. Intriguingly, one of the leukocidins, Leukocidin AB (LukAB), is found associated with the bacterial cell envelope in addition to secreted into the extracellular milieu. Here, we report that retention of LukAB on the bacterial cells provides S. aureus with a pre-synthesized active toxin that kills immune cells. On the bacteria, LukAB is distributed as discrete foci in two distinct compartments: membrane-proximal and surface-exposed. Through genetic screens, we show that a membrane lipid, lysyl-phosphatidylglycerol (LPG), and lipoteichoic acid (LTA) contribute to LukAB deposition and release. Furthermore, by studying non-covalently surface-bound proteins we discovered that the sorting of additional exoproteins, such as IsaB, Hel, ScaH, and Geh, are also controlled by LPG and LTA. Collectively, our study reveals a multistep secretion system that controls exoprotein storage and protein translocation across the S. aureus cell wall.
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Kumar NG, Contaifer D, Wijesinghe DS, Jefferson KK. Staphylococcus aureus Lipase 3 (SAL3) is a surface-associated lipase that hydrolyzes short chain fatty acids. PLoS One 2021; 16:e0258106. [PMID: 34618844 PMCID: PMC8496776 DOI: 10.1371/journal.pone.0258106] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 09/20/2021] [Indexed: 11/18/2022] Open
Abstract
Bacterial lipases play important roles during infection. The Staphylococcus aureus genome contains several genes that encode well-characterized lipases and several genes predicted to encode lipases or esterases for which the function has not yet been established. In this study, we sought to define the function of an uncharacterized S. aureus protein, and we propose the annotation S. aureus lipase 3 (SAL3) (SAUSA300_0641). We confirmed that SAL3 is a lipase and that it is surface associated and secreted through an unknown mechanism. We determined that SAL3 specifically hydrolyzes short chain (4-carbon and fewer) fatty acids and specifically binds negatively charged lipids including phosphatidic acid, phosphatidylinositol phosphate, and phosphatidylglycerol, which is the most abundant lipid in the staphylococcal cell membrane. Mutating the catalytic triad S66-A, D167-A, S168-A, and H301-A in the recombinant protein abolished lipase activity without altering binding to host lipid substrates. Taken together we report the discovery of a novel lipase from S. aureus specific to short chain fatty acids with yet to be determined roles in host pathogen interactions.
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Affiliation(s)
- Naren Gajenthra Kumar
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Daniel Contaifer
- Department of Pharmacotherapy and Outcomes Sciences, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Dayanjan S. Wijesinghe
- Department of Pharmacotherapy and Outcomes Sciences, School of Pharmacy, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kimberly K. Jefferson
- Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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25
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Chen X, Teoh WP, Stock MR, Resko ZJ, Alonzo F. Branched chain fatty acid synthesis drives tissue-specific innate immune response and infection dynamics of Staphylococcus aureus. PLoS Pathog 2021; 17:e1009930. [PMID: 34496007 PMCID: PMC8452012 DOI: 10.1371/journal.ppat.1009930] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/20/2021] [Accepted: 08/30/2021] [Indexed: 12/13/2022] Open
Abstract
Fatty acid-derived acyl chains of phospholipids and lipoproteins are central to bacterial membrane fluidity and lipoprotein function. Though it can incorporate exogenous unsaturated fatty acids (UFA), Staphylococcus aureus synthesizes branched chain fatty acids (BCFA), not UFA, to modulate or increase membrane fluidity. However, both endogenous BCFA and exogenous UFA can be attached to bacterial lipoproteins. Furthermore, S. aureus membrane lipid content varies based upon the amount of exogenous lipid in the environment. Thus far, the relevance of acyl chain diversity within the S. aureus cell envelope is limited to the observation that attachment of UFA to lipoproteins enhances cytokine secretion by cell lines in a TLR2-dependent manner. Here, we leveraged a BCFA auxotroph of S. aureus and determined that driving UFA incorporation disrupted infection dynamics and increased cytokine production in the liver during systemic infection of mice. In contrast, infection of TLR2-deficient mice restored inflammatory cytokines and bacterial burden to wildtype levels, linking the shift in acyl chain composition toward UFA to detrimental immune activation in vivo. In in vitro studies, bacterial lipoproteins isolated from UFA-supplemented cultures were resistant to lipase-mediated ester hydrolysis and exhibited heightened TLR2-dependent innate cell activation, whereas lipoproteins with BCFA esters were completely inactivated after lipase treatment. These results suggest that de novo synthesis of BCFA reduces lipoprotein-mediated TLR2 activation and improves lipase-mediated hydrolysis making it an important determinant of innate immunity. Overall, this study highlights the potential relevance of cell envelope acyl chain repertoire in infection dynamics of bacterial pathogens.
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Affiliation(s)
- Xi Chen
- Department of Microbiology and Immunology, Loyola University Chicago–Stritch School of Medicine, Maywood, Illinois, United States of America
| | - Wei Ping Teoh
- Department of Microbiology and Immunology, Loyola University Chicago–Stritch School of Medicine, Maywood, Illinois, United States of America
| | - Madison R. Stock
- Department of Microbiology and Immunology, Loyola University Chicago–Stritch School of Medicine, Maywood, Illinois, United States of America
| | - Zachary J. Resko
- Department of Microbiology and Immunology, Loyola University Chicago–Stritch School of Medicine, Maywood, Illinois, United States of America
| | - Francis Alonzo
- Department of Microbiology and Immunology, Loyola University Chicago–Stritch School of Medicine, Maywood, Illinois, United States of America
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Sargison F, Goncheva MI, Alves J, Pickering A, Fitzgerald JR. Staphylococcus aureus secreted lipases do not inhibit innate immune killing mechanisms. Wellcome Open Res 2021; 5:286. [PMID: 33623827 PMCID: PMC7871421 DOI: 10.12688/wellcomeopenres.16194.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2021] [Indexed: 11/20/2022] Open
Abstract
Background:Staphylococcus aureus causes an array of diseases in both humans and livestock. Pathogenesis is mediated by a plethora of proteins secreted by
S. aureus, many of which remain incompletely characterised. For example,
S. aureus abundantly secretes two isoforms of the enzyme lipase into the extracellular milieu, where they scavenge upon polymeric triglycerides. It has previously been suggested that lipases may interfere with the function of innate immune cells, such as macrophages and neutrophils, but the impact of lipases on phagocytic killing mechanisms remains unknown. Methods: We employed the epidemic
S. aureus clone USA300 strain LAC and its lipase deficient isogenic mutant, along with recombinant lipase proteins, in
in vitro experimental infection assays. To determine if lipases can inhibit innate immune killing mechanisms, the bactericidal activity of whole blood, human neutrophils, and macrophages was analysed. In addition, gentamycin protection assays were carried out to examine the influence of lipases on
S. aureus innate immune cell escape. Results: There were no differences in the survival of
S. aureus USA300 LAC wild type and its lipase-deficient isogenic mutant after incubation with human whole blood or neutrophils. Furthermore, there was no detectable lipase-dependent effect on phagocytosis, intracellular survival, or escape from both human primary and immortalised cell line macrophages, even upon supplementation with exogenous recombinant lipases. Conclusions: S. aureus lipases do not inhibit bacterial killing mechanisms of human macrophages, neutrophils, or whole blood. These findings broaden our understanding of the interaction of
S. aureus with the innate immune system.
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27
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Kang CY, Kang EYC, Lai CC, Lo WC, Chen KJ, Wu WC, Liu L, Hwang YS, Lo FS, Huang YC. Nasal Methicillin-Resistant Staphylococcus aureus Colonization in Patients with Type 1 Diabetes in Taiwan. Microorganisms 2021; 9:microorganisms9061296. [PMID: 34203580 PMCID: PMC8232090 DOI: 10.3390/microorganisms9061296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/24/2022] Open
Abstract
Nasal methicillin-resistant Staphylococcus aureus (MRSA) colonies are an essential reservoir of infection, especially for patients with diabetes. However, data on MRSA colonization in patients with type 1 diabetes are limited. We investigated the epidemiology of MRSA colonization in patients with type 1 diabetes. This prospective cross-sectional study was conducted in a medical center (Chang Gung Memorial Hospital) in Taiwan from 1 July to 31 December 2020. Nasal sampling and MRSA detection were performed. The molecular characteristics of MRSA isolates were tested, and factors associated with MRSA colonization were analyzed. We included 245 patients with type 1 diabetes; nasal MRSA colonization was identified in 13 (5.3%) patients. All isolates belonged to community-associated MRSA genetic strains; the most frequent strain was clonal complex 45 (53.8%), followed by ST59 (30.8%) (a local community strain). MRSA colonization was positively associated with age ≤ 10 years, body mass index < 18 kg/m2, and diabetes duration < 10 years; moreover, it was negatively associated with serum low-density lipoprotein cholesterol ≥ 100 mg/dL. No independent factor was reported. The nasal MRSA colonization rate in type 1 diabetes is approximately 5% in Taiwan. Most of these colonizing strains are community strains, namely clonal complex 45 and ST59.
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Affiliation(s)
- Chun-Ya Kang
- School of Medicine, Medical University of Lublin, 20529 Lublin, Poland;
| | - Eugene Yu-Chuan Kang
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
| | - Chi-Chun Lai
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
- Department of Family Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Wei-Che Lo
- Department of Ophthalmology, Keelung Chang Gung Memorial Hospital, Keelung 204, Taiwan;
| | - Kun-Jen Chen
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
| | - Wei-Chi Wu
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
| | - Laura Liu
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
| | - Yih-Shiou Hwang
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
| | - Fu-Sung Lo
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Division of Pediatric Endocrinology and Genetics, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
- Correspondence: (F.-S.L.); (Y.-C.H.); Tel.: +886-3-3281200 (F.-S.L. & Y.-C.H.)
| | - Yhu-Chering Huang
- College of Medicine, Chang Gung University, Taoyuan 333, Taiwan; (E.Y.-C.K.); (C.-C.L.); (K.-J.C.); (W.-C.W.); (L.L.); (Y.-S.H.)
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 333, Taiwan
- Correspondence: (F.-S.L.); (Y.-C.H.); Tel.: +886-3-3281200 (F.-S.L. & Y.-C.H.)
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Taurine-Mediated IDOL Contributes to Resolution of Streptococcus uberis Infection. Infect Immun 2021; 89:IAI.00788-20. [PMID: 33593888 DOI: 10.1128/iai.00788-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/01/2021] [Indexed: 12/17/2022] Open
Abstract
Metabolic alterations occur in pathogenic infections, but the role of lipid metabolism in the progression of bacterial mastitis is unclear. Cross talk between lipid droplets (LDs) and invading bacteria occurs, and targeting of de novo lipogenesis inhibits pathogen reproduction. In this study, we investigate the role(s) of lipid metabolism in mammary cells during Streptococcus uberis infection. Our results indicate that S. uberis induces the synthesis of fatty acids and production of LDs. Importantly, taurine reduces fatty acid synthesis, the abundance of LDs and the in vitro bacterial load of S. uberis These changes are mediated, at least partly, by the E3 ubiquitin ligase IDOL, which is associated with the degradation of low-density lipoprotein receptors (LDLRs). We have identified a critical role for IDOL-mediated fatty acid synthesis in bacterial infection, and we suggest that taurine may be an effective prophylactic or therapeutic strategy for preventing S. uberis mastitis.
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29
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Staphylococcus aureus adapts to the host nutritional landscape to overcome tissue-specific branched-chain fatty acid requirement. Proc Natl Acad Sci U S A 2021; 118:2022720118. [PMID: 33753501 DOI: 10.1073/pnas.2022720118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
During infection, pathogenic microbes adapt to the nutritional milieu of the host through metabolic reprogramming and nutrient scavenging. For the bacterial pathogen Staphylococcus aureus, virulence in diverse infection sites is driven by the ability to scavenge myriad host nutrients, including lipoic acid, a cofactor required for the function of several critical metabolic enzyme complexes. S. aureus shuttles lipoic acid between these enzyme complexes via the amidotransferase, LipL. Here, we find that acquisition of lipoic acid, or its attachment via LipL to enzyme complexes required for the generation of acetyl-CoA and branched-chain fatty acids, is essential for bacteremia, yet dispensable for skin infection in mice. A lipL mutant is auxotrophic for carboxylic acid precursors required for synthesis of branched-chain fatty acids, an essential component of staphylococcal membrane lipids and the agent of membrane fluidity. However, the skin is devoid of branched-chain fatty acids. We showed that S. aureus instead scavenges host-derived unsaturated fatty acids from the skin using the secreted lipase, Geh, and the unsaturated fatty acid-binding protein, FakB2. Moreover, murine infections demonstrated the relevance of host lipid assimilation to staphylococcal survival. Altogether, these studies provide insight into an adaptive trait that bypasses de novo lipid synthesis to facilitate S. aureus persistence during superficial infection. The findings also reinforce the inherent challenges associated with targeting bacterial lipogenesis as an antibacterial strategy and support simultaneous inhibition of host fatty acid salvage during treatment.
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30
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Pidwill GR, Gibson JF, Cole J, Renshaw SA, Foster SJ. The Role of Macrophages in Staphylococcus aureus Infection. Front Immunol 2021; 11:620339. [PMID: 33542723 PMCID: PMC7850989 DOI: 10.3389/fimmu.2020.620339] [Citation(s) in RCA: 119] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/02/2020] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus aureus is a member of the human commensal microflora that exists, apparently benignly, at multiple sites on the host. However, as an opportunist pathogen it can also cause a range of serious diseases. This requires an ability to circumvent the innate immune system to establish an infection. Professional phagocytes, primarily macrophages and neutrophils, are key innate immune cells which interact with S. aureus, acting as gatekeepers to contain and resolve infection. Recent studies have highlighted the important roles of macrophages during S. aureus infections, using a wide array of killing mechanisms. In defense, S. aureus has evolved multiple strategies to survive within, manipulate and escape from macrophages, allowing them to not only subvert but also exploit this key element of our immune system. Macrophage-S. aureus interactions are multifaceted and have direct roles in infection outcome. In depth understanding of these host-pathogen interactions may be useful for future therapeutic developments. This review examines macrophage interactions with S. aureus throughout all stages of infection, with special emphasis on mechanisms that determine infection outcome.
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Affiliation(s)
- Grace R Pidwill
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.,Florey Institute, University of Sheffield, Sheffield, United Kingdom
| | - Josie F Gibson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.,Florey Institute, University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Joby Cole
- Florey Institute, University of Sheffield, Sheffield, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Stephen A Renshaw
- Florey Institute, University of Sheffield, Sheffield, United Kingdom.,The Bateson Centre, University of Sheffield, Sheffield, United Kingdom.,Department of Infection, Immunity and Cardiovascular Disease, Medical School, University of Sheffield, Sheffield, United Kingdom
| | - Simon J Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom.,Florey Institute, University of Sheffield, Sheffield, United Kingdom
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31
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Lanza B, Cellini M, Di Marco S, D’Amico E, Simone N, Giansante L, Pompilio A, Di Loreto G, Bacceli M, Del Re P, Di Bonaventura G, Di Giacinto L, Aceto GM. Olive Pâté by Multi-Phase Decanter as Potential Source of Bioactive Compounds of Both Nutraceutical and Anticancer Effects. Molecules 2020; 25:molecules25245967. [PMID: 33339392 PMCID: PMC7767102 DOI: 10.3390/molecules25245967] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/07/2020] [Accepted: 12/13/2020] [Indexed: 11/16/2022] Open
Abstract
In the oil sector, a novelty in the centrifugal extraction system is represented by the multi-phase decanters (DMF) that work without adding process water and with the advantage of recovering a dried pomace and a by-product, called “pâté”, consisting of the pulp and its vegetation water, without traces of stone. The pâté has a high content of phenolic compounds, mainly represented by secoiridoids and verbascoside. The present work investigated the efficacy of two different ways of debittering (by sequential filtrations and spontaneous fermentation) of DMF pâté from three olive cultivars (Olea europaea L. “Leccino”, “Carboncella” and “Tortiglione”) to make the pâté edible, and, contemporary, investigated also the effect of its phenolic bioactive extracts on pathogenic bacteria and colon cancer cell model. Daily filtrations of pâté of the three cultivars have been shown to be more efficient in phenolic degradation. The activity of the indigenous microflora on the other hand takes a longer time to degrade the phenolic component and therefore to de-bitter it. None of pâté showed antibacterial activity. Colorimetric assay MTS for cell viability and metabolic activity tested on colon cancer cells Caco-2 and HCT116 suggest a potential beneficial effect of the dried extracts probably related to the modulation of gene expression under these treatments.
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Affiliation(s)
- Barbara Lanza
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
- Correspondence:
| | - Martina Cellini
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Sara Di Marco
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Emira D’Amico
- Department of Medical, Oral and Biotechnological Sciences, “G. d’Annunzio” University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy; (E.D.); (A.P.); (G.D.B.); (G.M.A.)
| | - Nicola Simone
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Lucia Giansante
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Arianna Pompilio
- Department of Medical, Oral and Biotechnological Sciences, “G. d’Annunzio” University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy; (E.D.); (A.P.); (G.D.B.); (G.M.A.)
- Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, Via Luigi Polacchi 11, 66100 Chieti, Italy
| | - Giuseppina Di Loreto
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Martina Bacceli
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Paolo Del Re
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Giovanni Di Bonaventura
- Department of Medical, Oral and Biotechnological Sciences, “G. d’Annunzio” University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy; (E.D.); (A.P.); (G.D.B.); (G.M.A.)
- Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, Via Luigi Polacchi 11, 66100 Chieti, Italy
| | - Luciana Di Giacinto
- Council for Agricultural Research and Economics (CREA), Research Centre for Engineering and Agro-Food Processing (CREA-IT), Via Lombardia, 65012 Cepagatti, Italy; (M.C.); (S.D.M.); (N.S.); (L.G.); (G.D.L.); (M.B.); (P.D.R.); (L.D.G.)
| | - Gitana Maria Aceto
- Department of Medical, Oral and Biotechnological Sciences, “G. d’Annunzio” University of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy; (E.D.); (A.P.); (G.D.B.); (G.M.A.)
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Sargison F, Alves J, Pickering A, Fitzgerald JR. Staphylococcus aureus secreted lipases do not inhibit innate immune killing mechanisms. Wellcome Open Res 2020; 5:286. [DOI: 10.12688/wellcomeopenres.16194.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2020] [Indexed: 11/20/2022] Open
Abstract
Background: Staphylococcus aureus causes an array of diseases in both humans and livestock. Pathogenesis is mediated by a plethora of proteins secreted by S. aureus, many of which remain incompletely characterised. For example, S. aureus abundantly secretes two isoforms of the enzyme lipase into the extracellular milieu, where they scavenge upon polymeric triglycerides. It has previously been suggested that lipases may interfere with the function of innate immune cells, such as macrophages and neutrophils, but the impact of lipases on phagocytic killing mechanisms remains unknown. Methods: We employed the epidemic S. aureus clone USA300 strain LAC and its lipase deficient isogenic mutant, along with recombinant lipase proteins, in in vitro experimental infection assays. To determine if lipases can inhibit innate immune killing mechanisms, the bactericidal activity of whole blood, human neutrophils, and macrophages was analysed. In addition, gentamycin protection assays were carried out to examine the influence of lipases on S. aureus innate immune cell escape. Results: There were no differences in the survival of S. aureus USA300 LAC wild type and its lipase-deficient isogenic mutant after incubation with human whole blood or neutrophils. Furthermore, there was no detectable lipase-dependent effect on phagocytosis, intracellular survival, or escape from both human primary and immortalised cell line macrophages, even upon supplementation with exogenous recombinant lipases. Conclusions: S. aureus lipases do not inhibit bacterial killing mechanisms of human macrophages, neutrophils, or whole blood. These findings broaden our understanding of the interaction of S. aureus with the innate immune system.
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Kénanian G, Morvan C, Weckel A, Pathania A, Anba-Mondoloni J, Halpern D, Gaillard M, Solgadi A, Dupont L, Henry C, Poyart C, Fouet A, Lamberet G, Gloux K, Gruss A. Permissive Fatty Acid Incorporation Promotes Staphylococcal Adaptation to FASII Antibiotics in Host Environments. Cell Rep 2020; 29:3974-3982.e4. [PMID: 31851927 DOI: 10.1016/j.celrep.2019.11.071] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/01/2019] [Accepted: 11/15/2019] [Indexed: 02/08/2023] Open
Abstract
The essentiality of fatty acid synthesis (FASII) products in the human pathogen Staphylococcus aureus is the underlying rationale for FASII-targeted antimicrobial drug design. Reports of anti-FASII efficacy in animals support this choice. However, restricted test conditions used previously led us to investigate this postulate in a broader, host-relevant context. We report that S. aureus rapidly adapts to FASII antibiotics without FASII mutations when exposed to host environments. FASII antibiotic administration upon signs of infection, rather than just after inoculation as commonly practiced, fails to eliminate S. aureus in a septicemia model. In vitro, serum lowers S. aureus membrane stress, leading to a greater retention of the substrates required for environmental fatty acid (eFA) utilization: eFAs and the acyl carrier protein. In this condition, eFA occupies both phospholipid positions, regardless of anti-FASII selection. Our results identify S. aureus membrane plasticity in host environments as a main limitation for using FASII antibiotics in monotherapeutic treatments.
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Affiliation(s)
- Gérald Kénanian
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Claire Morvan
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Antonin Weckel
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France
| | - Amit Pathania
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Jamila Anba-Mondoloni
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - David Halpern
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Marine Gaillard
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France
| | - Audrey Solgadi
- SAMM, UMS IPSIT, Faculté de Pharmacie, Université Paris-Saclay, Chatenay-Malabry, France
| | - Laetitia Dupont
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Céline Henry
- PAPPSO Platform, Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, France
| | - Claire Poyart
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France; Centre National de Référence des Streptocoques, Hôpitaux Universitaires Paris Centre Site Cochin, APHP, Paris, France
| | - Agnès Fouet
- Université de Paris, Institut Cochin, INSERM, U1016, CNRS, UMR8104, 75014 Paris, France
| | - Gilles Lamberet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Karine Gloux
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France
| | - Alexandra Gruss
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy en Josas, France.
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The type VII secretion system protects Staphylococcus aureus against antimicrobial host fatty acids. Sci Rep 2020; 10:14838. [PMID: 32908165 PMCID: PMC7481793 DOI: 10.1038/s41598-020-71653-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
The Staphylococcus aureus type VII secretion system (T7SS) exports several proteins that are pivotal for bacterial virulence. The mechanisms underlying T7SS-mediated staphylococcal survival during infection nevertheless remain unclear. Here we report that S. aureus lacking T7SS components are more susceptible to host-derived antimicrobial fatty acids. Unsaturated fatty acids such as linoleic acid (LA) elicited an increased inhibition of S. aureus mutants lacking T7SS effectors EsxC, EsxA and EsxB, or the membrane-bound ATPase EssC, compared to the wild-type (WT). T7SS mutants generated in different S. aureus strain backgrounds also displayed an increased sensitivity to LA. Analysis of bacterial membrane lipid profiles revealed that the esxC mutant was less able to incorporate LA into its membrane phospholipids. Although the ability to bind labelled LA did not differ between the WT and mutant strains, LA induced more cell membrane damage in the T7SS mutants compared to the WT. Furthermore, proteomic analyses of WT and mutant cell fractions revealed that, in addition to compromising membranes, T7SS defects induce oxidative stress and hamper their response to LA challenge. Thus, our findings indicate that T7SS contribute to maintaining S. aureus membrane integrity and homeostasis when bacteria encounter antimicrobial fatty acids.
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Yang Y, Chen Y, Zhang G, Sun J, Guo L, Jiang M, Ou B, Zhang W, Si H. Transcriptomic Analysis of Staphylococcus aureus Under the Stress Condition Caused by Litsea cubeba L. Essential Oil via RNA Sequencing. Front Microbiol 2020; 11:1693. [PMID: 33013718 PMCID: PMC7509438 DOI: 10.3389/fmicb.2020.01693] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/29/2020] [Indexed: 01/31/2023] Open
Abstract
Litsea cubeba L. essential oil (LCEO) is a natural essential oil with considerable antimicrobial activity, and it can gradually replace some chemical additives in the food industry. However, the genetic evidences of stress response of bacteria under sub-lethal treatment with LCEO is limited. To this end, transcriptomic analysis of Staphylococcus aureus 29213 under a low concentration of LCEO was performed. Bacterial RNA samples were extracted from 1/4 MIC (0.07 μL/mL) of LCEO-treated and non-treated S. aureus 29213. The transcriptional results were obtained by RNA sequencing (RNA-Seq). After treated with LCEO of S. aureus 29213, 300, and 242 genes were significantly up and down-regulated. Up-regulated genes were mainly related to cell membrane (wall) stress stimulon including genes related to two-component regulatory system (VraS), histidine metabolism (hisABCD etc.) and L-lysine biosynthesis (thrA, lysC, asd etc.). Significant differences were also founded between LCEO-treated and non-treated groups in peptidoglycan biosynthesis related pathways. Down-regulated genes were related to nitrogen metabolism (NarGHIJ etc.), carotenoid biosynthesis (all) and pyruvate metabolism (phdA, pflB, pdhC etc.) of S. aureus 29213 in an LCEO-existing environment compared to the control. At the same time, we confirmed that LCEO can significantly affect the staphyloxanthin level of S. aureus 29213 for the first time, which is closely related to the redox state of S. aureus 29213. These evidences expanded the knowledge of stress response of S. aureus 29213 strain under sub-lethal concentration of LCEO.
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Affiliation(s)
- Yunqiao Yang
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
| | - Yunru Chen
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
| | - Geyin Zhang
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
| | - Junying Sun
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
| | - Lei Guo
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China
| | - Mingsheng Jiang
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
| | - Bingming Ou
- College of Life Science, Zhaoqing University, Zhaoqing, China
| | - Weiyu Zhang
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
| | - Hongbin Si
- College of Animal Sciences and Technology, Guangxi University, Nanning, China
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Exogenous Fatty Acids Remodel Staphylococcus aureus Lipid Composition through Fatty Acid Kinase. J Bacteriol 2020; 202:JB.00128-20. [PMID: 32366591 DOI: 10.1128/jb.00128-20] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/29/2020] [Indexed: 12/30/2022] Open
Abstract
Staphylococcus aureus can utilize exogenous fatty acids for phospholipid synthesis. The fatty acid kinase FakA is essential for this utilization by phosphorylating exogenous fatty acids for incorporation into lipids. How FakA impacts the lipid membrane composition is unknown. In this study, we used mass spectrometry to determine the membrane lipid composition and properties of S. aureus in the absence of fakA We found the fakA mutant to have increased abundance of lipids containing longer acyl chains. Since S. aureus does not synthesize unsaturated fatty acids, we utilized oleic acid (18:1) to track exogenous fatty acid incorporation into lipids. We observed a concentration-dependent incorporation of exogenous fatty acids into the membrane that required FakA. We also tested how FakA and exogenous fatty acids impact membrane-related physiology and identified changes in membrane potential, cellular respiration, and membrane fluidity. To mimic the host environment, we characterized the lipid composition of wild-type and fakA mutant bacteria grown in mouse skin homogenate. We show that wild-type S. aureus can incorporate exogenous unsaturated fatty acids from host tissue, highlighting the importance of FakA in the presence of host skin tissue. In conclusion, FakA is important for maintaining the composition and properties of the phospholipid membrane in the presence of exogenous fatty acids, impacting overall cell physiology.IMPORTANCE Environmental fatty acids can be harvested to supplement endogenous fatty acid synthesis to produce membranes and circumvent fatty acid biosynthesis inhibitors. However, how the inability to use these fatty acids impacts lipids is unclear. Our results reveal lipid composition changes in response to fatty acid addition and when S. aureus is unable to activate fatty acids through FakA. We identify concentration-dependent utilization of oleic acid that, when combined with previous work, provides evidence that fatty acids can serve as a signal to S. aureus Furthermore, using mouse skin homogenates as a surrogate for in vivo conditions, we showed that S. aureus can incorporate host fatty acids. This study highlights how exogenous fatty acids impact bacterial membrane composition and function.
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Lipidomic and Ultrastructural Characterization of the Cell Envelope of Staphylococcus aureus Grown in the Presence of Human Serum. mSphere 2020; 5:5/3/e00339-20. [PMID: 32554713 PMCID: PMC7300354 DOI: 10.1128/msphere.00339-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Comprehensive lipidomics of S. aureus grown in the presence of human serum suggests that human serum lipids can associate with the cell envelope without being truly integrated into the lipid membrane. However, fatty acids derived from human serum lipids, including unsaturated fatty acids, can be incorporated into lipid classes that can be biosynthesized by S. aureus itself. Cholesteryl esters and triglycerides are found to be the major source of incorporated fatty acids upon hydrolysis by lipases. These findings have significant implications for the nature of the S. aureus cell surface when grown in vivo. Changes in phospholipid and glycolipid abundances and fatty acid composition could affect membrane biophysics and function and the activity of membrane-targeting antimicrobials. Finally, the association of serum lipids with the cell envelope has implications for the physicochemical nature of the cell surface and its interaction with host defense systems. Staphylococcus aureus can incorporate exogenous straight-chain unsaturated and saturated fatty acids (SCUFAs and SCFAs, respectively) to replace some of the normally biosynthesized branched-chain fatty acids and SCFAs. In this study, the impact of human serum on the S. aureus lipidome and cell envelope structure was comprehensively characterized. When S. aureus was grown in the presence of 20% human serum, typical human serum lipids, such as cholesterol, sphingomyelin, phosphatidylethanolamines, and phosphatidylcholines, were present in the total lipid extracts. Mass spectrometry showed that SCUFAs were incorporated into all major S. aureus lipid classes, i.e., phosphatidylglycerols, lysyl-phosphatidylglycerols, cardiolipins, and diglucosyldiacylglycerols. Heat-killed S. aureus retained fewer serum lipids and failed to incorporate SCUFAs, suggesting that association and incorporation of serum lipids with S. aureus require a living or nondenatured cell. Cytoplasmic membranes isolated from lysostaphin-produced protoplasts of serum-grown cells retained serum lipids, but washing cells with Triton X-100 removed most of them. Furthermore, electron microscopy studies showed that serum-grown cells had thicker cell envelopes and associated material on the surface, which was partially removed by Triton X-100 washing. To investigate which serum lipids were preferentially hydrolyzed by S. aureus lipases for incorporation, we incubated individual serum lipid classes with S. aureus and found that cholesteryl esters (CEs) and triglycerides (TGs) are the major donors of the incorporated fatty acids. Further experiments using purified Geh lipase confirmed that CEs and TGs were the substrates of this enzyme. Thus, growth in the presence of serum altered the nature of the cell surface with implications for interactions with the host. IMPORTANCE Comprehensive lipidomics of S. aureus grown in the presence of human serum suggests that human serum lipids can associate with the cell envelope without being truly integrated into the lipid membrane. However, fatty acids derived from human serum lipids, including unsaturated fatty acids, can be incorporated into lipid classes that can be biosynthesized by S. aureus itself. Cholesteryl esters and triglycerides are found to be the major source of incorporated fatty acids upon hydrolysis by lipases. These findings have significant implications for the nature of the S. aureus cell surface when grown in vivo. Changes in phospholipid and glycolipid abundances and fatty acid composition could affect membrane biophysics and function and the activity of membrane-targeting antimicrobials. Finally, the association of serum lipids with the cell envelope has implications for the physicochemical nature of the cell surface and its interaction with host defense systems.
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Tiwari KB, Gatto C, Wilkinson BJ. Plasticity of Coagulase-Negative Staphylococcal Membrane Fatty Acid Composition and Implications for Responses to Antimicrobial Agents. Antibiotics (Basel) 2020; 9:E214. [PMID: 32354049 PMCID: PMC7277709 DOI: 10.3390/antibiotics9050214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 04/18/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus demonstrates considerable membrane lipid plasticity in response to different growth environments, which is of potential relevance to response and resistance to various antimicrobial agents. This information is not available for various species of coagulase-negative staphylococci, which are common skin inhabitants, can be significant human pathogens, and are resistant to multiple antibiotics. We determined the total fatty acid compositions of Staphylococcus auricularis, Staphylococcus capitis, Staphylococcus epidermidis, Staphylococcus haemolyticus, Staphylococcus hominis, Staphylococcus saprophyticus, and Staphylococcus aureus for comparison purposes. Different proportions of branched-chain and straight-chain fatty acids were observed amongst the different species. However, growth in cation-supplemented Mueller-Hinton broth significantly increased the proportion of branched-chain fatty acids, and membrane fluidities as measured by fluorescence anisotropy. Cation-supplemented Mueller-Hinton broth is used for routine determination of antimicrobial susceptibilities. Growth in serum led to significant increases in straight-chain unsaturated fatty acids in the total fatty acid profiles, and decreases in branched-chain fatty acids. This indicates preformed fatty acids can replace biosynthesized fatty acids in the glycerolipids of coagulase-negative staphylococci, and indicates that bacterial fatty acid biosynthesis system II may not be a good target for antimicrobial agents in these organisms. Even though the different species are expected to be exposed to skin antimicrobial fatty acids, they were susceptible to the major skin antimicrobial fatty acid sapienic acid (C16:1Δ6). Certain species were not susceptible to linoleic acid (C18:2Δ9,12), but no obvious relationship to fatty acid composition could be discerned.
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Affiliation(s)
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL 61761, USA
| | - Brian J. Wilkinson
- School of Biological Sciences, Illinois State University, Normal, IL 61761, USA
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Kitadokoro K, Tanaka M, Hikima T, Okuno Y, Yamamoto M, Kamitani S. Crystal structure of pathogenic Staphylococcus aureus lipase complex with the anti-obesity drug orlistat. Sci Rep 2020; 10:5469. [PMID: 32214208 PMCID: PMC7096528 DOI: 10.1038/s41598-020-62427-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/11/2020] [Indexed: 12/26/2022] Open
Abstract
Staphylococcus aureus lipase (SAL), a triacylglycerol esterase, is an important virulence factor and may be a therapeutic target for infectious diseases. Herein, we determined the 3D structure of native SAL, the mutated S116A inactive form, and the inhibitor complex using the anti-obesity drug orlistat to aid in drug development. The determined crystal structures showed a typical α/β hydrolase motif with a dimeric form. Fatty acids bound near the active site in native SAL and inactive S116A mutant structures. We found that orlistat potently inhibits SAL activity, and it covalently bound to the catalytic Ser116 residue. This is the first report detailing orlistat–lipase binding. It provides structure-based information on the production of potent anti-SAL drugs and lipase inhibitors. These results also indicated that orlistat can be repositioned to treat bacterial diseases.
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Affiliation(s)
- Kengo Kitadokoro
- Faculty of Molecular Chemistry and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Hashigami-cho, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
| | - Mutsumi Tanaka
- Faculty of Molecular Chemistry and Engineering, Graduate School of Science and Technology, Kyoto Institute of Technology, Hashigami-cho, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Takaaki Hikima
- SR Life Science Instrumentation Team, Life Science Research Infrastructure Group, Advanced Photon Technology Division, RIKEN SPring-8 Center, 1-1-1, Koto, Sayo-cho, Sayo-gun, Hyogo, 679-6148, Japan
| | - Yukiko Okuno
- Medical Research Support Center, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Masaki Yamamoto
- SR Life Science Instrumentation Team, Life Science Research Infrastructure Group, Advanced Photon Technology Division, RIKEN SPring-8 Center, 1-1-1, Koto, Sayo-cho, Sayo-gun, Hyogo, 679-6148, Japan
| | - Shigeki Kamitani
- Graduate School of Comprehensive Rehabilitation, College of Health and Human Sciences, Osaka Prefecture University, 3-7-30 Habikino, Habikino, 583-8555, Osaka, Japan
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40
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Szemraj M, Grazul M, Balcerczak E, Szewczyk EM. Staphylococcal species less frequently isolated from human clinical specimens - are they a threat for hospital patients? BMC Infect Dis 2020; 20:128. [PMID: 32046678 PMCID: PMC7014773 DOI: 10.1186/s12879-020-4841-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/31/2020] [Indexed: 11/23/2022] Open
Abstract
Background Coagulase-negative staphylococci belonging to S. haemolyticus, S. hominis subsp. hominis, S. simulans, and S. warneri are often described as etiological factors of infections. Staphylococci are a phylogenetically coherent group; nevertheless, there are differences among the species which may be important to clinicians. Methods We investigated selected virulence factors and antibiotic resistance that were phenotypically demonstrated, the presence and expression of genes encoding the virulence factors, and the type of the SCCmec cassette. Results The differences between the tested species were revealed. A great number of isolates produced a biofilm and many of them contained single icaADBC operon genes. Clear differences between species in the lipolytic activity spectrum could be related to their ability to cause various types of infections. Our studies also revealed the presence of genes encoding virulence factors homologous to S. aureus in the analysed species such as enterotoxin and pvl genes, which were also expressed in single isolates of S. simulans and S. warneri. S. haemolyticus and S. hominis subsp. hominis isolates were resistant to all clinically important antibiotics including ß-lactams. The identified SCCmec cassettes belonged to IV, V, VII, and IX type but most of the detected cassettes were non-typeable. Among the investigated species, S. hominis subsp. hominis isolates accumulated virulence genes typical for S. aureus in the most efficient way and were widely resistant to antibiotics. Conclusions Our results clearly indicated significant differences between the tested species, which might be a result of the horizontal gene transfer (HGT) and can lead to the formation and selection of multi-drug resistant strains as well as strains with new virulence features. Such strains can have a new clinical relevance.
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Affiliation(s)
- Magdalena Szemraj
- Department of Pharmaceutical Microbiology and Microbiological Diagnostic, Medical University of Lodz, Pomorska 137, 90-235, Łódź, Poland.
| | - Magdalena Grazul
- Department of Pharmaceutical Microbiology and Microbiological Diagnostic, Medical University of Lodz, Pomorska 137, 90-235, Łódź, Poland
| | - Ewa Balcerczak
- Department of Pharmaceutical Biochemistry and Molecular Diagnostic, Laboratory of Molecular Diagnostic and Pharmacogenomics, Medical University of Lodz, Łódź, Poland
| | - Eligia M Szewczyk
- Department of Pharmaceutical Microbiology and Microbiological Diagnostic, Medical University of Lodz, Pomorska 137, 90-235, Łódź, Poland
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Kronenberger T, de Oliveira Fernades P, Drumond Franco I, Poso A, Gonçalves Maltarollo V. Ligand- and Structure-Based Approaches of Escherichia coli FabI Inhibition by Triclosan Derivatives: From Chemical Similarity to Protein Dynamics Influence. ChemMedChem 2019; 14:1995-2004. [PMID: 31670463 PMCID: PMC6916556 DOI: 10.1002/cmdc.201900415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/03/2019] [Indexed: 12/20/2022]
Abstract
Enoyl-acyl carrier protein reductase (FabI) is the limiting step to complete the elongation cycle in type II fatty acid synthase (FAS) systems and is a relevant target for antibacterial drugs. E. coli FabI has been employed as a model to develop new inhibitors against FAS, especially triclosan and diphenyl ether derivatives. Chemical similarity models (CSM) were used to understand which features were relevant for FabI inhibition. Exhaustive screening of different CSM parameter combinations featured chemical groups, such as the hydroxy group, as relevant to distinguish between active/decoy compounds. Those chemical features can interact with the catalytic Tyr156. Further molecular dynamics simulation of FabI revealed the ionization state as a relevant for ligand stability. Also, our models point the balance between potency and the occupancy of the hydrophobic pocket. This work discusses the strengths and weak points of each technique, highlighting the importance of complementarity among approaches to elucidate EcFabI inhibitor's binding mode and offers insights for future drug discovery.
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Affiliation(s)
- Thales Kronenberger
- Department of Medical Oncology and Pneumology, Internal Medicine VIIIUniversity Hospital of TübingenOtfried-Müller-Strasse 1472076TübingenGermany
- School of PharmacyUniversity of Eastern Finland Faculty of Health SciencesKuopio70211Finland
| | - Philipe de Oliveira Fernades
- Departamento de Produtos Farmacêuticos, Faculdade de FarmáciaUniversidade Federal de Minas GeraisAv. Antônio Carlos6627Pampulha, Belo Horizonte, MG, 31270-901Brazil
- Departamento de Química, Instituto de Ciências ExatasUniversidade Federal de Minas GeraisAv. Antônio Carlos6627 –Pampulha, Belo Horizonte, MG, 31270-901Brazil
| | - Isabella Drumond Franco
- Departamento de Produtos Farmacêuticos, Faculdade de FarmáciaUniversidade Federal de Minas GeraisAv. Antônio Carlos6627Pampulha, Belo Horizonte, MG, 31270-901Brazil
| | - Antti Poso
- Department of Medical Oncology and Pneumology, Internal Medicine VIIIUniversity Hospital of TübingenOtfried-Müller-Strasse 1472076TübingenGermany
- School of PharmacyUniversity of Eastern Finland Faculty of Health SciencesKuopio70211Finland
| | - Vinícius Gonçalves Maltarollo
- Departamento de Produtos Farmacêuticos, Faculdade de FarmáciaUniversidade Federal de Minas GeraisAv. Antônio Carlos6627Pampulha, Belo Horizonte, MG, 31270-901Brazil
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Dynamic Relay of Protein-Bound Lipoic Acid in Staphylococcus aureus. J Bacteriol 2019; 201:JB.00446-19. [PMID: 31451544 DOI: 10.1128/jb.00446-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 08/21/2019] [Indexed: 12/19/2022] Open
Abstract
Staphylococcus aureus competes for myriad essential nutrients during host infection. One of these nutrients is the organosulfur compound lipoic acid, a cofactor required for the activity of several metabolic enzyme complexes. In S. aureus, these include the E2 subunits of three α-ketoacid dehydrogenases and two H proteins, GcvH of the glycine cleavage system and its paralog, GcvH-L. We previously determined that the S. aureus amidotransferase LipL is required for lipoylation of the E2 subunits of pyruvate dehydrogenase (PDH) and branched-chain 2-oxoacid dehydrogenase (BCODH) complexes. The results from this study, coupled with those from Bacillus subtilis, suggested that LipL catalyzes lipoyl transfer from H proteins to E2 subunits. However, to date, the range of LipL targets, the extent of LipL-dependent lipoic acid shuttling between lipoyl domain-containing proteins, and the importance of lipoyl relay in pathogenesis remain unknown. Here, we demonstrate that LipL uses both lipoyl-H proteins as the substrates for lipoyl transfer to all E2 subunits. Moreover, LipL facilitates lipoyl relay between E2 subunits and between H proteins, a property that potentially constitutes an adaptive response to nutrient scarcity in the host, as LipL is required for virulence during infection. Together, these observations support a role for LipL in facilitating flexible lipoyl relay between proteins and highlight the complexity of protein lipoylation in S. aureus IMPORTANCE Protein lipoylation is a posttranslational modification that is evolutionarily conserved from bacteria to humans. Lipoic acid modifications are found on five proteins in S. aureus, four of which are components of major metabolic enzymes. In some bacteria, the amidotransferase LipL is critical for the attachment of lipoic acid to these proteins, and yet it is unclear to what extent LipL facilitates the transfer of this cofactor. We find that S. aureus LipL flexibly shuttles lipoic acid among metabolic enzyme subunits, alluding to a dynamic redistribution mechanism within the bacterial cell. This discovery exemplifies a potential means by which bacteria optimize the use of scarce nutrients when resources are limited.
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Gullett JM, Cuypers MG, Frank MW, White SW, Rock CO. A fatty acid-binding protein of Streptococcus pneumoniae facilitates the acquisition of host polyunsaturated fatty acids. J Biol Chem 2019; 294:16416-16428. [PMID: 31530637 PMCID: PMC6827280 DOI: 10.1074/jbc.ra119.010659] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/16/2019] [Indexed: 11/06/2022] Open
Abstract
Streptococcus pneumoniae is responsible for the majority of pneumonia, motivating ongoing searches for insights into its physiology that could enable new treatments. S. pneumoniae responds to exogenous fatty acids by suppressing its de novo biosynthetic pathway and exclusively utilizing extracellular fatty acids for membrane phospholipid synthesis. The first step in exogenous fatty acid assimilation is phosphorylation by fatty acid kinase (FakA), whereas bound by a fatty acid-binding protein (FakB). Staphylococcus aureus has two binding proteins, whereas S. pneumoniae expresses three. The functions of these binding proteins were not clear. We determined the SpFakB1- and SpFakB2-binding proteins were bioinformatically related to the two binding proteins of Staphylococcus aureus, and biochemical and X-ray crystallographic analysis showed that SpFakB1 selectively bound saturates, whereas SpFakB2 allows the activation of monounsaturates akin to their S. aureus counterparts. The distinct SpFakB3 enables the utilization of polyunsaturates. The SpFakB3 crystal structure in complex with linoleic acid reveals an expanded fatty acid-binding pocket within the hydrophobic interior of SpFakB3 that explains its ability to accommodate multiple cis double bonds. SpFakB3 also utilizes a different hydrogen bond network than other FakBs to anchor the fatty acid carbonyl and stabilize the protein. S. pneumoniae strain JMG1 (ΔfakB3) was deficient in incorporation of linoleate from human serum verifying the role of FakB3 in this process. Thus, the multiple FakBs of S. pneumoniae permit the utilization of the entire spectrum of mammalian fatty acid structures to construct its membrane.
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Affiliation(s)
- Jessica M Gullett
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Maxime G Cuypers
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Matthew W Frank
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Stephen W White
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
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Otopathogenic Staphylococcus aureus Invades Human Middle Ear Epithelial Cells Primarily through Cholesterol Dependent Pathway. Sci Rep 2019; 9:10777. [PMID: 31346200 PMCID: PMC6658548 DOI: 10.1038/s41598-019-47079-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 06/26/2019] [Indexed: 01/20/2023] Open
Abstract
Chronic suppurative otitis media (CSOM) is one of the most common infectious diseases of the middle ear especially affecting children, leading to delay in language development and communication. Although Staphylococcus aureus is the most common pathogen associated with CSOM, its interaction with middle ear epithelial cells is not well known. In the present study, we observed that otopathogenic S. aureus has the ability to invade human middle ear epithelial cells (HMEECs) in a dose and time dependent manner. Scanning electron microscopy demonstrated time dependent increase in the number of S. aureus on the surface of HMEECs. We observed that otopathogenic S. aureus primarily employs a cholesterol dependent pathway to colonize HMEECs. In agreement with these findings, confocal microscopy showed that S. aureus colocalized with lipid rafts in HMEECs. The results of the present study provide new insights into the pathogenesis of S. aureus induced CSOM. The availability of in vitro cell culture model will pave the way to develop novel effective treatment modalities for CSOM beyond antibiotic therapy.
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A FASII Inhibitor Prevents Staphylococcal Evasion of Daptomycin by Inhibiting Phospholipid Decoy Production. Antimicrob Agents Chemother 2019; 63:AAC.02105-18. [PMID: 30718253 PMCID: PMC6496159 DOI: 10.1128/aac.02105-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
Daptomycin is a treatment of last resort for serious infections caused by drug-resistant Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus. We have shown recently that S. aureus can evade daptomycin by releasing phospholipid decoys that sequester and inactivate the antibiotic, leading to treatment failure. Daptomycin is a treatment of last resort for serious infections caused by drug-resistant Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus. We have shown recently that S. aureus can evade daptomycin by releasing phospholipid decoys that sequester and inactivate the antibiotic, leading to treatment failure. Since phospholipid release occurs via an active process, we hypothesized that it could be inhibited, thereby increasing daptomycin efficacy. To identify opportunities for therapeutic interventions that block phospholipid release, we first determined how the host environment influences the release of phospholipids and the inactivation of daptomycin by S. aureus. The addition of certain host-associated fatty acids to the growth medium enhanced phospholipid release. However, in serum, the sequestration of fatty acids by albumin restricted their availability to S. aureus sufficiently to prevent their use in the generation of released phospholipids. This finding implies that in host tissues S. aureus may be completely dependent upon endogenous phospholipid biosynthesis to generate lipids for release, providing a target for therapeutic intervention. To test this, we exposed S. aureus to AFN-1252, an inhibitor of the staphylococcal FASII fatty acid biosynthetic pathway, together with daptomycin. AFN-1252 efficiently blocked daptomycin-induced phospholipid decoy production, even in the case of isolates resistant to AFN-1252, which prevented the inactivation of daptomycin and resulted in sustained bacterial killing. In turn, daptomycin prevented the fatty acid-dependent emergence of AFN-1252-resistant isolates in vitro. In summary, AFN-1252 significantly enhances daptomycin activity against S. aureusin vitro by blocking the production of phospholipid decoys, while daptomycin blocks the emergence of resistance to AFN-1252.
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Chen X, Alonzo F. Bacterial lipolysis of immune-activating ligands promotes evasion of innate defenses. Proc Natl Acad Sci U S A 2019; 116:3764-3773. [PMID: 30755523 PMCID: PMC6397559 DOI: 10.1073/pnas.1817248116] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Commensal and pathogenic bacteria hydrolyze host lipid substrates with secreted lipases and phospholipases for nutrient acquisition, colonization, and infection. Bacterial lipase activity on mammalian lipids and phospholipids can promote release of free fatty acids from lipid stores, detoxify antimicrobial lipids, and facilitate membrane dissolution. The gram-positive bacterium Staphylococcus aureus secretes at least two lipases, Sal1 and glycerol ester hydrolase (Geh), with specificities for short- and long-chain fatty acids, respectively, each with roles in the hydrolysis of environmental lipids. In a recent study from our group, we made the unexpected observation that Geh released by S. aureus inhibits activation of innate immune cells. Herein, we investigated the possibility that S. aureus lipases interface with the host immune system to blunt innate immune recognition of the microbe. We found that the Geh lipase, but not other S. aureus lipases, prevents activation of innate cells in culture. Mutation of geh leads to enhancement of proinflammatory cytokine production during infection, increased innate immune activity, and improved clearance of the bacterium in infected tissue. These in vitro and in vivo effects on innate immunity were not due to direct functions of the lipase on mammalian cells, but rather a result of inactivation of S. aureus lipoproteins, a major pathogen-associated molecular pattern (PAMP) of extracellular gram-positive bacteria, via ester hydrolysis. Altogether, these studies provide insight into an adaptive trait that masks microbial recognition by innate immune cells through targeted inactivation of a broadly conserved PAMP.
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Affiliation(s)
- Xi Chen
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
| | - Francis Alonzo
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153
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Krute CN, Ridder MJ, Seawell NA, Bose JL. Inactivation of the exogenous fatty acid utilization pathway leads to increased resistance to unsaturated fatty acids in Staphylococcus aureus. MICROBIOLOGY-SGM 2018; 165:197-207. [PMID: 30566075 DOI: 10.1099/mic.0.000757] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The human pathogen Staphylococcus aureus produces saturated fatty acids, but can incorporate both exogenous saturated and unsaturated fatty acids into its lipid membrane. S. aureus encounters unsaturated fatty acids in the host skin where they serve as an innate immune defence due to their toxicity. Previously, we identified a fatty acid kinase in S. aureus that is necessary for the utilization of exogenous fatty acids. The goal of this study was to determine the effects of fatty acids on mutants deficient in the exogenous fatty acid utilization machinery. We have demonstrated that mutants lacking a functional fatty acid kinase (fakA) or both fatty acid carrier proteins (fakB1 fakB2) are more resistant to unsaturated fatty acids. Previous studies suggested a role for ammonia-producing enzymes in resistance to unsaturated fatty acids, but these enzymes do not contribute to the resistance of the fakA mutant, despite increased urease transcription and protein activity in the mutant. Additionally, while pigment is altered in mutants unable to use exogenous fatty acids, staphyloxanthin does not contribute to fatty acid resistance of an fakA mutant. Because exposure to unsaturated fatty acids probably initiates a stress response, we investigated the role of the alternative sigma factor σB and determined if it is necessary for the fatty acid resistance observed in the fakA mutant. Collectively, this study demonstrates that the inability to incorporate unsaturated fatty acids leads to increased resistance to those fatty acids, and that resistance requires a σB stress response.
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Affiliation(s)
- Christina N Krute
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Miranda J Ridder
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nichole A Seawell
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jeffrey L Bose
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Champion PA, Shrout JD. The 24th Annual Midwest Microbial Pathogenesis Meeting. J Bacteriol 2018; 200:e000950-18. [PMID: 29483166 PMCID: PMC5952387 DOI: 10.1128/jb.00095-18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 24th Annual Midwest Microbial Pathogenesis Conference (MMPC) was held at the University of Notre Dame from August 25-27, 2017. The conference provided an opportunity for scientists from the Midwest to discuss new advances in microbial pathogenesis, including how pathogens promote disease, and how they interact with each other, the microbiome and the host. This commentary highlights the MMPC history, the topics presented at the conference and the reports in this issue.
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Affiliation(s)
- Patricia A. Champion
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Joshua D. Shrout
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, Indiana, USA
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