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Harris-Jones TN, Chan JM, Hackett KT, Weyand NJ, Schaub RE, Dillard JP. Peptidoglycan fragment release and NOD activation by commensal Neisseria species from humans and other animals. Infect Immun 2024; 92:e0000424. [PMID: 38563734 PMCID: PMC11075463 DOI: 10.1128/iai.00004-24] [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: 01/04/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
Neisseria gonorrhoeae, a human restricted pathogen, releases inflammatory peptidoglycan (PG) fragments that contribute to the pathophysiology of pelvic inflammatory disease. The genus Neisseria is also home to multiple species of human- or animal-associated Neisseria that form part of the normal microbiota. Here we characterized PG release from the human-associated nonpathogenic species Neisseria lactamica and Neisseria mucosa and animal-associated Neisseria from macaques and wild mice. An N. mucosa strain and an N. lactamica strain were found to release limited amounts of the proinflammatory monomeric PG fragments. However, a single amino acid difference in the PG fragment permease AmpG resulted in increased PG fragment release in a second N. lactamica strain examined. Neisseria isolated from macaques also showed substantial release of PG monomers. The mouse colonizer Neisseria musculi exhibited PG fragment release similar to that seen in N. gonorrhoeae with PG monomers being the predominant fragments released. All the human-associated species were able to stimulate NOD1 and NOD2 responses. N. musculi was a poor inducer of mouse NOD1, but ldcA mutation increased this response. The ability to genetically manipulate N. musculi and examine effects of different PG fragments or differing amounts of PG fragments during mouse colonization will lead to a better understanding of the roles of PG in Neisseria infections. Overall, we found that only some nonpathogenic Neisseria have diminished release of proinflammatory PG fragments, and there are differences even within a species as to types and amounts of PG fragments released.
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Affiliation(s)
- Tiffany N. Harris-Jones
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jia Mun Chan
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kathleen T. Hackett
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nathan J. Weyand
- Department of Biological Sciences, Ohio University, Athens, Ohio, USA
| | - Ryan E. Schaub
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Joseph P. Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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2
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Garcia EM, Lenz JD, Schaub RE, Hackett KT, Salgado-Pabón W, Dillard JP. IL-17C is a driver of damaging inflammation during Neisseria gonorrhoeae infection of human Fallopian tube. Nat Commun 2024; 15:3756. [PMID: 38704381 PMCID: PMC11069574 DOI: 10.1038/s41467-024-48141-3] [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: 12/07/2022] [Accepted: 04/19/2024] [Indexed: 05/06/2024] Open
Abstract
The human pathogen Neisseria gonorrhoeae ascends into the upper female reproductive tract to cause damaging inflammation within the Fallopian tubes and pelvic inflammatory disease (PID), increasing the risk of infertility and ectopic pregnancy. The loss of ciliated cells from the epithelium is thought to be both a consequence of inflammation and a cause of adverse sequelae. However, the links between infection, inflammation, and ciliated cell extrusion remain unresolved. With the use of ex vivo cultures of human Fallopian tube paired with RNA sequencing we defined the tissue response to gonococcal challenge, identifying cytokine, chemokine, cell adhesion, and apoptosis related transcripts not previously recognized as potentiators of gonococcal PID. Unexpectedly, IL-17C was one of the most highly induced genes. Yet, this cytokine has no previous association with gonococcal infection nor pelvic inflammatory disease and thus it was selected for further characterization. We show that human Fallopian tubes express the IL-17C receptor on the epithelial surface and that treatment with purified IL-17C induces pro-inflammatory cytokine secretion in addition to sloughing of the epithelium and generalized tissue damage. These results demonstrate a previously unrecognized but critical role of IL-17C in the damaging inflammation induced by gonococci in a human explant model of PID.
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Affiliation(s)
- Erin M Garcia
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Jonathan D Lenz
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Ryan E Schaub
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Kathleen T Hackett
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Wilmara Salgado-Pabón
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA.
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3
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Koh YC, Chang YC, Lin WS, Leung SY, Chen WJ, Wu SH, Wei YS, Gung CL, Chou YC, Pan MH. Efficacy and Mechanism of the Action of Live and Heat-Killed Bacillus coagulans BC198 as Potential Probiotic in Ameliorating Dextran Sulfate Sodium-Induced Colitis in Mice. ACS OMEGA 2024; 9:10253-10266. [PMID: 38463297 PMCID: PMC10918820 DOI: 10.1021/acsomega.3c07529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 02/01/2024] [Accepted: 02/12/2024] [Indexed: 03/12/2024]
Abstract
Inflammatory bowel disease alters the gut microbiota, causes defects in mucosal barrier function, and leads to dysregulation of the immune response to microbial stimulation. This study investigated and compared the efficacy of a candidate probiotic strain, Bacillus coagulans BC198, and its heat-killed form in treating dextran sulfate sodium-induced colitis. Both live and heat-killed B. coagulans BC198 increased gut barrier-associated protein expression, reduced neutrophil and M1 macrophage infiltration of colon tissue, and corrected gut microbial dysbiosis induced by colitis. However, only live B. coagulans BC198 could alleviate the general symptoms of colitis, prevent colon shortening, and suppress inflammation and tissue damage. At the molecular level, live B. coagulans BC198 was able to inhibit Th17 cells while promoting Treg cells in mice with colitis, reduce pro-inflammatory MCP-1 production, and increase anti-inflammatory IL-10 expression in the colonic mucosa. The live form of B. coagulans BC198 functioned more effectively than the heat-killed form in ameliorating colitis by enhancing the anti-inflammatory response and promoting Treg cell accumulation in the colon.
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Affiliation(s)
- Yen-Chun Koh
- Institute
of Food Sciences and Technology, National
Taiwan University, Taipei 10617, Taiwan
| | - Ya-Chu Chang
- Institute
of Food Sciences and Technology, National
Taiwan University, Taipei 10617, Taiwan
| | - Wei-Sheng Lin
- Institute
of Food Sciences and Technology, National
Taiwan University, Taipei 10617, Taiwan
- Department
of Food Science, National Quemoy University, Quemoy 892, Taiwan
| | - Siu-Yi Leung
- Institute
of Food Sciences and Technology, National
Taiwan University, Taipei 10617, Taiwan
| | - Wei-Jen Chen
- Biotech
Department, Syngen Biotech Co., Ltd., Tainan 744094, Taiwan
| | - Shiuan-Huei Wu
- Biotech
Department, Syngen Biotech Co., Ltd., Tainan 744094, Taiwan
| | - Yu-Shan Wei
- Research
and Development Department, Syngen Biotech
Co., Ltd., Tainan 744094, Taiwan
| | - Chiau-Ling Gung
- Research
and Development Department, Syngen Biotech
Co., Ltd., Tainan 744094, Taiwan
| | - Ya-Chun Chou
- Institute
of Food Sciences and Technology, National
Taiwan University, Taipei 10617, Taiwan
| | - Min-Hsiung Pan
- Institute
of Food Sciences and Technology, National
Taiwan University, Taipei 10617, Taiwan
- Department
of Medical Research, China Medical University Hospital, China Medical University, Taichung City 40402, Taiwan
- Department
of Health and Nutrition Biotechnology, Asia
University, Taichung City 41354, Taiwan
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4
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Gao S, Gao L, Yuan D, Lin X, van der Veen S. Gonococcal OMV-delivered PorB induces epithelial cell mitophagy. Nat Commun 2024; 15:1669. [PMID: 38396029 PMCID: PMC10891091 DOI: 10.1038/s41467-024-45961-1] [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: 10/17/2023] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
The bacterial pathogen Neisseria gonorrhoeae is able to invade epithelial cells and survive intracellularly. During this process, it secretes outer membrane vesicles (OMVs), however, the mechanistic details for interactions between gonococcal OMVs and epithelial cells and their impact on intracellular survival are currently not established. Here, we show that gonococcal OMVs induce epithelial cell mitophagy to reduce mitochondrial secretion of reactive oxygen species (ROS) and enhance intracellular survival. We demonstrate that OMVs deliver PorB to mitochondria to dissipate the mitochondrial membrane potential, resulting in mitophagy induction through a conventional PINK1 and OPTN/NDP52 mechanism. Furthermore, PorB directly recruits the E3 ubiquitin ligase RNF213, which decorates PorB lysine residue 171 with K63-linked polyubiquitin to induce mitophagy in a p62-dependent manner. These results demonstrate a mechanism in which polyubiquitination of a bacterial virulence factor that targets mitochondria directs mitophagy processes to this organelle to prevent its secretion of deleterious ROS.
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Affiliation(s)
- Shuai Gao
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
| | - Lingyu Gao
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
| | - Dailin Yuan
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, PR China
| | - Xu'ai Lin
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China
| | - Stijn van der Veen
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China.
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, PR China.
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Hangzhou, PR China.
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5
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Yao L, Liu Q, Lei Z, Sun T. Development and challenges of antimicrobial peptide delivery strategies in bacterial therapy: A review. Int J Biol Macromol 2023; 253:126819. [PMID: 37709236 DOI: 10.1016/j.ijbiomac.2023.126819] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/16/2023]
Abstract
The escalating global prevalence of antimicrobial resistance poses a critical threat, prompting concerns about its impact on public health. This predicament is exacerbated by the acute shortage of novel antimicrobial agents, a scarcity attributed to the rapid surge in bacterial resistance. This review delves into the realm of antimicrobial peptides, a diverse class of compounds ubiquitously present in plants and animals across various natural organisms. Renowned for their intrinsic antibacterial activity, these peptides provide a promising avenue to tackle the intricate challenge of bacterial resistance. However, the clinical utility of peptide-based drugs is hindered by limited bioavailability and susceptibility to rapid degradation, constraining efforts to enhance the efficacy of bacterial infection treatments. The emergence of nanocarriers marks a transformative approach poised to revolutionize peptide delivery strategies. This review elucidates a promising framework involving nanocarriers within the realm of antimicrobial peptides. This paradigm enables meticulous and controlled peptide release at infection sites by detecting dynamic shifts in microenvironmental factors, including pH, ROS, GSH, and reactive enzymes. Furthermore, a glimpse into the future reveals the potential of targeted delivery mechanisms, harnessing inflammatory responses and intricate signaling pathways, including adenosine triphosphate, macrophage receptors, and pathogenic nucleic acid entities. This approach holds promise in fortifying immunity, thereby amplifying the potency of peptide-based treatments. In summary, this review spotlights peptide nanosystems as prospective solutions for combating bacterial infections. By bridging antimicrobial peptides with advanced nanomedicine, a new therapeutic era emerges, poised to confront the formidable challenge of antimicrobial resistance head-on.
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Affiliation(s)
- Longfukang Yao
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China; Hubei Key Laboratory of Nanomedicine for Neurodegenerative Diseases, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China
| | - Qianying Liu
- School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhixin Lei
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China; Hubei Key Laboratory of Nanomedicine for Neurodegenerative Diseases, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
| | - Taolei Sun
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China; Hubei Key Laboratory of Nanomedicine for Neurodegenerative Diseases, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070, China.
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6
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Gao S, Yuan D, Gao L, Yang F, Lin X, van der Veen S. Epithelial Cell NOD1/IRGM Recruits STX17 to Neisseria gonorrhoeae-Containing Endosomes to Initiate Lysosomal Degradation. J Infect Dis 2023; 228:1776-1788. [PMID: 37926090 DOI: 10.1093/infdis/jiad478] [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: 08/01/2023] [Revised: 10/19/2023] [Accepted: 10/27/2023] [Indexed: 11/07/2023] Open
Abstract
Neisseria gonorrhoeae establishes tight interactions with mucosal epithelia through activity of its type IV pilus, while pilus retraction forces activate autophagic responses toward invading gonococci. Here we studied pilus-independent epithelial cell responses and showed that pilus-negative gonococci residing in early and late endosomes are detected and targeted by nucleotide-binding oligomerization domain 1 (NOD1). NOD1 subsequently forms a complex with immunity-related guanosine triphosphatase M (IRGM) and autophagy-related 16-like 1 (ATG16L1) to activate autophagy and recruit microtubule-associated protein light chain 3 (LC3) to the intracellular bacteria. IRGM furthermore directly recruits syntaxin 17 (STX17), which is able to form tethering complexes with the lysosome. Importantly, IRGM-STX17 interactions are enhanced by LC3 but were still observed at lower levels in an LC3 knockout cell line. These findings demonstrate key roles for NOD1 and IRGM in the sensing of intracellular N gonorrhoeae and subsequent directing of the bacterium to the lysosome for degradation.
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Affiliation(s)
- Shuai Gao
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Dailin Yuan
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining, People's Republic of China
| | - Lingyu Gao
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Fan Yang
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Xu'ai Lin
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Stijn van der Veen
- Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining, People's Republic of China
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Provincial Key Laboratory for Microbial Biochemistry and Metabolic Engineering, Zhejiang University, Hangzhou, People's Republic of China
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7
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Harris-Jones TN, Pérez Medina KM, Hackett KT, Schave MA, Klimowicz AK, Schaub RE, Dillard JP. Mutation of mltG increases peptidoglycan fragment release, cell size, and antibiotic susceptibility in Neisseria gonorrhoeae. J Bacteriol 2023; 205:e0027723. [PMID: 38038461 PMCID: PMC10729727 DOI: 10.1128/jb.00277-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 11/13/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE Neisseria gonorrhoeae is unusual in that the bacteria release larger amounts of cell wall material as they grow as compared to related bacteria, and the released cell wall fragments induce inflammation that leads to tissue damage in infected people. The study of MltG revealed the importance of this enzyme for controlling cell wall growth, cell wall fragment production, and bacterial cell size and suggests a role for MltG in a cell wall synthesis and degradation complex. The increased antibiotic sensitivities of mltG mutants suggest that an antimicrobial drug inhibiting MltG would be useful in combination therapy to restore the sensitivity of the bacteria to cell wall targeting antibiotics to which the bacteria are currently resistant.
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Affiliation(s)
- Tiffany N. Harris-Jones
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Krizia M. Pérez Medina
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Kathleen T. Hackett
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Melanie A. Schave
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Amy K. Klimowicz
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Ryan E. Schaub
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Joseph P. Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
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8
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Figueroa-Cuilan WM, Irazoki O, Feeley M, Smith E, Nguyen T, Cava F, Goley ED. Quantitative analysis of morphogenesis and growth dynamics in an obligate intracellular bacterium. Mol Biol Cell 2023; 34:ar69. [PMID: 37017481 PMCID: PMC10295487 DOI: 10.1091/mbc.e23-01-0023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/06/2023] Open
Abstract
Obligate intracellular bacteria of the order Rickettsiales include important human pathogens. However, our understanding of the biology of Rickettsia species is limited by challenges imposed by their obligate intracellular lifestyle. To overcome this roadblock, we developed methods to assess cell wall composition, growth, and morphology of Rickettsia parkeri, a human pathogen in the spotted fever group of the Rickettsia genus. Analysis of the cell wall of R. parkeri revealed unique features that distinguish it from free-living alphaproteobacteria. Using a novel fluorescence microscopy approach, we quantified R. parkeri morphology in live host cells and found that the fraction of the population undergoing cell division decreased over the course of infection. We further demonstrated the feasibility of localizing fluorescence fusions, for example, to the cell division protein ZapA, in live R. parkeri for the first time. To evaluate population growth kinetics, we developed an imaging-based assay that improves on the throughput and resolution of other methods. Finally, we applied these tools to quantitatively demonstrate that the actin homologue MreB is required for R. parkeri growth and rod shape. Collectively, a toolkit was developed of high-throughput, quantitative tools to understand growth and morphogenesis of R. parkeri that is translatable to other obligate intracellular bacteria.
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Affiliation(s)
- Wanda M. Figueroa-Cuilan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Marissa Feeley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Erika Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Trung Nguyen
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine, Umeå Center for Microbial Research, Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185
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9
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The AmiC/NlpD pathway dominates peptidoglycan breakdown in Neisseria meningitidis and affects cell separation, NOD1 agonist production, and infection. Infect Immun 2022; 90:e0048521. [PMID: 35225652 DOI: 10.1128/iai.00485-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human-restricted pathogen Neisseria meningitidis, which is best known for causing invasive meningococcal disease, has a nonpathogenic lifestyle as an asymptomatic colonizer of the human naso- and oropharyngeal space. N. meningitidis releases small peptidoglycan (PG) fragments during growth. It was demonstrated previously that N. meningitidis releases low levels of tripeptide PG monomer, which is an inflammatory molecule recognized by the human intracellular innate immune receptor NOD1. In this present study, we demonstrated that N. meningitidis released more PG-derived peptides compared to PG monomers. Using a reporter cell line overexpressing human NOD1, we showed that N. meningitidis activates NOD1 using PG-derived peptides. Generation of such peptides required the presence of the periplasmic N-acetylmuramyl-L-alanine amidase AmiC, and the outer membrane lipoprotein, NlpD. AmiC and NlpD were found to function in cell separation, and mutation of either amiC or nlpD resulted in large clumps of unseparated N. meningitidis cells instead of the characteristic diplococci. Using stochastic optical reconstruction microscopy, we demonstrated that FLAG epitope-tagged NlpD localized to the septum, while similarly-tagged AmiC was found at the septum in some diplococci but distributed around the cell in most cases. In a human whole blood infection assay, an nlpD mutant was severely attenuated and showed particular sensitivity to complement. Thus, in N. meningitidis the cell separation proteins AmiC and NlpD are necessary for NOD1 stimulation and for survival during infection of human blood.
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10
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Horizontal-Acquisition of a Promiscuous Peptidoglycan-Recycling Enzyme Enables Aphids To Influence Symbiont Cell Wall Metabolism. mBio 2021; 12:e0263621. [PMID: 34933456 PMCID: PMC8689515 DOI: 10.1128/mbio.02636-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
During evolution, enzymes can undergo shifts in preferred substrates or in catalytic activities. An intriguing question is how enzyme function changes following horizontal gene transfer, especially for bacterial genes that have moved to animal genomes. Some insects have acquired genes that encode enzymes for the biosynthesis of bacterial cell wall components and that appear to function to support or control their obligate endosymbiotic bacteria. In aphids, the bacterial endosymbiont Buchnera aphidicola provides essential amino acids for aphid hosts but lacks most genes for remodeling of the bacterial cell wall. The aphid genome has acquired seven genes with putative functions in cell wall metabolism that are primarily expressed in the aphid cells harboring Buchnera. In analyses of aphid homogenates, we detected peptidoglycan (PGN) muropeptides indicative of the reactions of PGN hydrolases encoded by horizontally acquired aphid genes but not by Buchnera genes. We produced one such host enzyme, ApLdcA, and characterized its activity with both cell wall derived and synthetic PGN. Both ApLdcA and the homologous enzyme in Escherichia coli, which functions as an l,d-carboxypeptidase in the cytoplasmic PGN recycling pathway, exhibit turnover of PGN substrates containing stem pentapeptides and cross-linkages via l,d-endopeptidase activity, consistent with a potential role in cell wall remodeling. Our results suggest that ApLdcA derives its functions from the promiscuous activities of an ancestral LdcA enzyme, whose acquisition by the aphid genome may have enabled hosts to influence Buchnera cell wall metabolism as a means to control symbiont growth and division. IMPORTANCE Most enzymes are capable of performing biologically irrelevant side reactions. During evolution, promiscuous enzyme activities may acquire new biological roles, especially after horizontal gene transfer to new organisms. Pea aphids harbor obligate bacterial symbionts called Buchnera and encode horizontally acquired bacterial genes with putative roles in cell wall metabolism. Though Buchnera lacks cell wall endopeptidase genes, we found evidence of endopeptidase activity among peptidoglycan muropeptides purified from aphids. We characterized a multifunctional, aphid-encoded enzyme, ApLdcA, which displays l,d-endopeptidase activities considered promiscuous for the Escherichia coli homolog, for which these activities do not contribute to its native role in peptidoglycan recycling. These results exemplify the roles of enzyme promiscuity and horizontal gene transfer in enzyme evolution and demonstrate how aphids influence symbiont cell wall metabolism.
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11
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Voedts H, Dorchêne D, Lodge A, Vollmer W, Arthur M, Hugonnet JE. Role of endopeptidases in peptidoglycan synthesis mediated by alternative cross-linking enzymes in Escherichia coli. EMBO J 2021; 40:e108126. [PMID: 34382698 DOI: 10.15252/embj.2021108126] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 07/22/2021] [Accepted: 07/24/2021] [Indexed: 12/20/2022] Open
Abstract
Bacteria resist to the turgor pressure of the cytoplasm through a net-like macromolecule, the peptidoglycan, made of glycan strands connected via peptides cross-linked by penicillin-binding proteins (PBPs). We recently reported the emergence of β-lactam resistance resulting from a bypass of PBPs by the YcbB L,D-transpeptidase (LdtD), which form chemically distinct 3→3 cross-links compared to 4→3 formed by PBPs. Here we show that peptidoglycan expansion requires controlled hydrolysis of cross-links and identify among eight endopeptidase paralogues the minimum enzyme complements essential for bacterial growth with 4→3 (MepM) and 3→3 (MepM and MepK) cross-links. Purified Mep endopeptidases unexpectedly displayed a 4→3 and 3→3 dual specificity implying recognition of a common motif in the two cross-link types. Uncoupling of the polymerization of glycan chains from the 4→3 cross-linking reaction was found to facilitate the bypass of PBPs by YcbB. These results illustrate the plasticity of the peptidoglycan polymerization machinery in response to the selective pressure of β-lactams.
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Affiliation(s)
- Henri Voedts
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
| | - Delphine Dorchêne
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
| | - Adam Lodge
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Michel Arthur
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
| | - Jean-Emmanuel Hugonnet
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
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12
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Patel JG, Narra HP, Sepuru KM, Sahni A, Golla SR, Sahni A, Singh A, Schroeder CLC, Chowdhury IH, Popov VL, Sahni SK. Evolution, purification, and characterization of RC0497: a peptidoglycan amidase from the prototypical spotted fever species Rickettsia conorii. Biol Chem 2021; 401:249-262. [PMID: 31299006 DOI: 10.1515/hsz-2018-0389] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 06/29/2019] [Indexed: 12/12/2022]
Abstract
Rickettsial species have independently lost several genes owing to reductive evolution while retaining those predominantly implicated in virulence, survival, and biosynthetic pathways. In this study, we have identified a previously uncharacterized Rickettsia conorii gene RC0497 as an N-acetylmuramoyl-L-alanine amidase constitutively expressed during infection of cultured human microvascular endothelial cells at the levels of both mRNA transcript and encoded protein. A homology-based search of rickettsial genomes reveals that RC0497 homologs, containing amidase_2 family and peptidoglycan binding domains, are highly conserved among the spotted fever group (SFG) rickettsiae. The recombinant RC0497 protein exhibits α-helix secondary structure, undergoes a conformational change in the presence of zinc, and exists as a dimer at higher concentrations. We have further ascertained the enzymatic activity of RC0497 via demonstration of its ability to hydrolyze Escherichia coli peptidoglycan. Confocal microscopy on E. coli expressing RC0497 and transmission immunoelectron microscopy of R. conorii revealed its localization predominantly to the cell wall, septal regions of replicating bacteria, and the membrane of vesicles pinching off the cell wall. In summary, we have identified and functionally characterized RC0497 as a peptidoglycan hydrolase unique to spotted fever rickettsiae, which may potentially serve as a novel moonlighting protein capable of performing multiple functions during host-pathogen interactions.
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Affiliation(s)
- Jignesh G Patel
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Hema P Narra
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Krishna Mohan Sepuru
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Abha Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sandhya R Golla
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Aishwarya Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Amber Singh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Casey L C Schroeder
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Imran H Chowdhury
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Vsevolod L Popov
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sanjeev K Sahni
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA.,Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
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13
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Zellner B, Mengin-Lecreulx D, Tully B, Gunning WT, Booth R, Huntley JF. A Francisella tularensis L,D-carboxypeptidase plays important roles in cell morphology, envelope integrity, and virulence. Mol Microbiol 2021; 115:1357-1378. [PMID: 33469978 DOI: 10.1111/mmi.14685] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/15/2022]
Abstract
Francisella tularensis is a Gram-negative, intracellular bacterium that causes the zoonotic disease tularemia. Intracellular pathogens, including F. tularensis, have evolved mechanisms to survive in the harsh environment of macrophages and neutrophils, where they are exposed to cell envelope-damaging molecules. The bacterial cell wall, primarily composed of peptidoglycan (PG), maintains cell morphology, structure, and membrane integrity. Intracellular Gram-negative bacteria protect themselves from macrophage and neutrophil killing by recycling and repairing damaged PG--a process that involves over 50 different PG synthesis and recycling enzymes. Here, we identified a PG recycling enzyme, L,D-carboxypeptidase A (LdcA), of F. tularensis that is responsible for converting PG tetrapeptide stems to tripeptide stems. Unlike E. coli LdcA and most other orthologs, F. tularensis LdcA does not localize to the cytoplasm and also exhibits L,D-endopeptidase activity, converting PG pentapeptide stems to tripeptide stems. Loss of F. tularensis LdcA led to altered cell morphology and membrane integrity, as well as attenuation in a mouse pulmonary infection model and in primary and immortalized macrophages. Finally, an F. tularensis ldcA mutant protected mice against virulent Type A F. tularensis SchuS4 pulmonary challenge.
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Affiliation(s)
- Briana Zellner
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Brenden Tully
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
| | | | - Robert Booth
- Department of Pathology, University of Toledo, Toledo, OH, USA
| | - Jason F Huntley
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, USA
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14
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Guvenc F, Kaul R, Gray-Owen SD. Intimate Relations: Molecular and Immunologic Interactions Between Neisseria gonorrhoeae and HIV-1. Front Microbiol 2020; 11:1299. [PMID: 32582133 PMCID: PMC7284112 DOI: 10.3389/fmicb.2020.01299] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/20/2020] [Indexed: 12/20/2022] Open
Abstract
While the global incidence of human immunodeficiency virus (HIV-1) remains well above UNAIDS targets, sexual transmission HIV is surprisingly inefficient. A variety of host, viral and environmental factors can either increase HIV-1 shedding in the infected partner and/or increase mucosal susceptibility of the HIV-1 uninfected partner. Clinical and epidemiological studies have clearly established that Neisseria gonorrhoeae substantially enhances HIV-1 transmission, despite it not being an ulcerative infection. This review will consider findings from molecular, immunologic and clinical studies that have focused on each of these two human-restricted pathogens, in order to develop an integrative model that describes how gonococci can both increase mucosal shedding of HIV-1 from a co-infected person and facilitate virus establishment in a susceptible host.
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Affiliation(s)
- Furkan Guvenc
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Rupert Kaul
- Department of Medicine, University of Toronto, Toronto, ON, Canada.,Department of Immunology, University of Toronto, Toronto, ON, Canada.,Division of Infectious Diseases, University Health Network, Toronto, ON, Canada
| | - Scott D Gray-Owen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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15
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Russell MW, Jerse AE, Gray-Owen SD. Progress Toward a Gonococcal Vaccine: The Way Forward. Front Immunol 2019; 10:2417. [PMID: 31681305 PMCID: PMC6803597 DOI: 10.3389/fimmu.2019.02417] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 09/27/2019] [Indexed: 12/26/2022] Open
Abstract
The concept of immunizing against gonorrhea has received renewed interest because of the recent emergence of strains of Neisseria gonorrhoeae that are resistant to most currently available antibiotics, an occurrence that threatens to render gonorrhea untreatable. However, despite efforts over many decades, no vaccine has yet been successfully developed for human use, leading to pessimism over whether this goal was actually attainable. Several factors have contributed to this situation, including extensive variation of the expression and specificity of many of the gonococcal surface antigens, and the ability of N. gonorrhoeae to resist destruction by complement and other innate immune defense mechanisms. The natural host restriction of N. gonorrhoeae for humans, coupled with the absence of any definable state of immunity arising from an episode of gonorrhea, have also complicated efforts to study gonococcal pathogenesis and the host's immune responses. However, recent findings have elucidated how the gonococcus exploits and manipulates the host's immune system for its own benefit, utilizing human-specific receptors for attachment to and invasion of tissues, and subverting adaptive immune responses that might otherwise be capable of eliminating it. While no single experimental model is capable of providing all the answers, experiments utilizing human cells and tissues in vitro, various in vivo animal models, including genetically modified strains of mice, and both experimental and observational human clinical studies, have combined to yield important new insight into the immuno-pathogenesis of gonococcal infection. In turn, these have now led to novel approaches for the development of a gonococcal vaccine. Ongoing investigations utilizing all available tools are now poised to make the development of an effective human vaccine against gonorrhea an achievable goal within a foreseeable time-frame.
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Affiliation(s)
- Michael W. Russell
- Department of Microbiology and Immunology, University at Buffalo, Buffalo, NY, United States
| | - Ann E. Jerse
- Department of Microbiology and Immunology, F. Edward Herbert School of Medicine, Uniformed Services University, Bethesda, MD, United States
| | - Scott D. Gray-Owen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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16
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Torrens G, Escobar-Salom M, Pol-Pol E, Camps-Munar C, Cabot G, López-Causapé C, Rojo-Molinero E, Oliver A, Juan C. Comparative Analysis of Peptidoglycans From Pseudomonas aeruginosa Isolates Recovered From Chronic and Acute Infections. Front Microbiol 2019; 10:1868. [PMID: 31507543 PMCID: PMC6719521 DOI: 10.3389/fmicb.2019.01868] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 07/29/2019] [Indexed: 12/20/2022] Open
Abstract
Pseudomonas aeruginosa is one of the first causes of acute nosocomial and chronic infections in patients with underlying respiratory pathologies such as cystic fibrosis (CF). It has been proposed that P. aeruginosa accumulates mutations driving to peptidoglycan modifications throughout the development of the CF-associated infection, as a strategy to lower the immune detection hence ameliorating the chronic persistence. As well, some studies dealing with peptidoglycan modifications driving to a better survival within the host have been published in other gram-negatives. According to these facts, the gram-negative peptidoglycan could be considered as a pathogen-associated molecular pattern with very important implications regarding the host’s detection-response, worthy to dissect in detail. For this reason, in this work we characterized for the first time the peptidoglycans of three large collections [early CF, late CF and acute infection (bloodstream) P. aeruginosa strains] from qualitative (HPLC), quantitative and inflammatory capacity-related perspectives. The final goal was to identify composition trends potentially supporting the cited strategy of evasion/resistance to the immune system and providing information regarding the differential intrinsic adaptation depending on the type of infection. Although we found several punctual strain-specific particularities, our results indicated a high degree of inter-collection uniformity in the peptidoglycan-related features and the absence of trends amongst the strains studied here. These results suggest that the peptidoglycan of P. aeruginosa is a notably conserved structure in natural isolates regardless of transitory changes that some external conditions could force. Finally, the inverse correlation between the relative amount of stem pentapeptides within the murein sacculus and the resistance to immune lytic attacks against the peptidoglycan was also suggested by our results. Altogether, this work is a major step ahead to understand the biology of peptidoglycan from P. aeruginosa natural strains, hopefully useful in future for therapeutic alternatives design.
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Affiliation(s)
- Gabriel Torrens
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - María Escobar-Salom
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Elisabet Pol-Pol
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Cristina Camps-Munar
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Gabriel Cabot
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Carla López-Causapé
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Estrella Rojo-Molinero
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Antonio Oliver
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
| | - Carlos Juan
- Servicio de Microbiología-Unidad de Investigación, Hospital Universitari Son Espases-Institut d'Investigació Sanitària Illes Balears (IdISBa), Palma, Spain
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17
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Piqué N, Berlanga M, Miñana-Galbis D. Health Benefits of Heat-Killed (Tyndallized) Probiotics: An Overview. Int J Mol Sci 2019; 20:E2534. [PMID: 31126033 PMCID: PMC6566317 DOI: 10.3390/ijms20102534] [Citation(s) in RCA: 271] [Impact Index Per Article: 54.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 02/07/2023] Open
Abstract
Nowadays, the oral use of probiotics is widespread. However, the safety profile with the use of live probiotics is still a matter of debate. Main risks include: Cases of systemic infections due to translocation, particularly in vulnerable patients and pediatric populations; acquisition of antibiotic resistance genes; or interference with gut colonization in neonates. To avoid these risks, there is an increasing interest in non-viable microorganisms or microbial cell extracts to be used as probiotics, mainly heat-killed (including tyndallized) probiotic bacteria (lactic acid bacteria and bifidobacteria). Heat-treated probiotic cells, cell-free supernatants, and purified key components are able to confer beneficial effects, mainly immunomodulatory effects, protection against enteropathogens, and maintenance of intestinal barrier integrity. At the clinical level, products containing tyndallized probiotic strains have had a role in gastrointestinal diseases, including bloating and infantile coli-in combination with mucosal protectors-and diarrhea. Heat-inactivated probiotics could also have a role in the management of dermatological or respiratory allergic diseases. The reviewed data indicate that heat-killed bacteria or their fractions or purified components have key probiotic effects, with advantages versus live probiotics (mainly their safety profile), positioning them as interesting strategies for the management of common prevalent conditions in a wide variety of patients´ characteristics.
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Affiliation(s)
- Núria Piqué
- Microbiology Section, Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, Universitat de Barcelona (UB), Av Joan XXIII, 27-31, 08028 Barcelona, Catalonia, Spain.
- Institut de Recerca en Nutrició i Seguretat Alimentària de la UB (INSA-UB), Universitat de Barcelona, 08921 Barcelona, Catalonia, Spain.
| | - Mercedes Berlanga
- Microbiology Section, Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, Universitat de Barcelona (UB), Av Joan XXIII, 27-31, 08028 Barcelona, Catalonia, Spain.
| | - David Miñana-Galbis
- Microbiology Section, Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, Universitat de Barcelona (UB), Av Joan XXIII, 27-31, 08028 Barcelona, Catalonia, Spain.
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18
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Schaub RE, Dillard JP. The Pathogenic Neisseria Use a Streamlined Set of Peptidoglycan Degradation Proteins for Peptidoglycan Remodeling, Recycling, and Toxic Fragment Release. Front Microbiol 2019; 10:73. [PMID: 30766523 PMCID: PMC6365954 DOI: 10.3389/fmicb.2019.00073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 01/15/2019] [Indexed: 12/26/2022] Open
Abstract
Neisseria gonorrhoeae and Neisseria meningitidis release peptidoglycan (PG) fragments from the cell as the bacteria grow. For N. gonorrhoeae these PG fragments are known to cause damage to human Fallopian tube tissue in organ culture that mimics the damage seen in patients with pelvic inflammatory disease. N. meningitidis also releases pro-inflammatory PG fragments, but in smaller amounts than those from N. gonorrhoeae. It is not yet known if PG fragment release contributes to the highly inflammatory conditions of meningitis and meningococcemia caused by N. meningitidis. Examination of the mechanisms of PG degradation and recycling identified proteins required for these processes. In comparison to the model organism E. coli, the pathogenic Neisseria have far fewer PG degradation proteins, and some of these proteins show differences in subcellular localization compared to their E. coli homologs. In particular, some N. gonorrhoeae PG degradation proteins were demonstrated to be in the outer membrane while their homologs in E. coli were found free in the periplasm or in the cytoplasm. The localization of two of these proteins was demonstrated to affect PG fragment release. Another major factor for PG fragment release is the allele of ampG. Gonococcal AmpG was found to be slightly defective compared to related PG fragment permeases, thus leading to increased release of PG. A number of additional PG-related factors affect other virulence functions in Neisseria. Endopeptidases and carboxypeptidases were found to be required for type IV pilus production and resistance to hydrogen peroxide. Also, deacetylation of PG was required for virulence of N. meningitidis as well as normal cell size. Overall, we describe the processes involved in PG degradation and recycling and how certain characteristics of these proteins influence the interactions of these pathogens with their host.
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Affiliation(s)
- Ryan E Schaub
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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19
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Neisseria gonorrhoeae PBP3 and PBP4 Facilitate NOD1 Agonist Peptidoglycan Fragment Release and Survival in Stationary Phase. Infect Immun 2019; 87:IAI.00833-18. [PMID: 30510100 DOI: 10.1128/iai.00833-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 11/25/2018] [Indexed: 01/16/2023] Open
Abstract
Neisseria gonorrhoeae releases peptidoglycan fragments during growth, and these molecules induce an inflammatory response in the human host. The proinflammatory molecules include peptidoglycan monomers, peptidoglycan dimers, and free peptides. These molecules can be released by the actions of lytic transglycosylases or an amidase. However, >40% of the gonococcal cell wall is cross-linked, where the peptide stem on one peptidoglycan strand is linked to the peptide stem on a neighboring strand, suggesting that endopeptidases may be required for the release of many peptidoglycan fragments. Therefore, we characterized mutants with individual or combined mutations in genes for the low-molecular-mass penicillin-binding proteins PBP3 and PBP4. Mutations in either dacB, encoding PBP3, or pbpG, encoding PBP4, did not significantly reduce the release of peptidoglycan monomers or free peptides. A mutation in dacB caused the appearance of a larger-sized peptidoglycan monomer, the pentapeptide monomer, and an increased release of peptidoglycan dimers, suggesting the involvement of this enzyme in both the removal of C-terminal d-Ala residues from stem peptides and the cleavage of cross-linked peptidoglycan. Mutation of both dacB and pbpG eliminated the release of tripeptide-containing peptidoglycan fragments concomitantly with the appearance of pentapeptide and dipeptide peptidoglycan fragments and higher-molecular-weight peptidoglycan dimers. In accord with the loss of tripeptide peptidoglycan fragments, the level of human NOD1 activation by the dacB pbpG mutants was significantly lower than that by the wild type. We conclude that PBP3 and PBP4 overlap in function for cross-link cleavage and that these endopeptidases act in the normal release of peptidoglycan fragments during growth.
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20
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Juan C, Torrens G, Barceló IM, Oliver A. Interplay between Peptidoglycan Biology and Virulence in Gram-Negative Pathogens. Microbiol Mol Biol Rev 2018; 82:e00033-18. [PMID: 30209071 PMCID: PMC6298613 DOI: 10.1128/mmbr.00033-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The clinical and epidemiological threat of the growing antimicrobial resistance in Gram-negative pathogens, particularly for β-lactams, the most frequently used and relevant antibiotics, urges research to find new therapeutic weapons to combat the infections caused by these microorganisms. An essential previous step in the development of these therapeutic solutions is to identify their potential targets in the biology of the pathogen. This is precisely what we sought to do in this review specifically regarding the barely exploited field analyzing the interplay among the biology of the peptidoglycan and related processes, such as β-lactamase regulation and virulence. Hence, here we gather, analyze, and integrate the knowledge derived from published works that provide information on the topic, starting with those dealing with the historically neglected essential role of the Gram-negative peptidoglycan in virulence, including structural, biogenesis, remodeling, and recycling aspects, in addition to proinflammatory and other interactions with the host. We also review the complex link between intrinsic β-lactamase production and peptidoglycan metabolism, as well as the biological costs potentially associated with the expression of horizontally acquired β-lactamases. Finally, we analyze the existing evidence from multiple perspectives to provide useful clues for identifying targets enabling the future development of therapeutic options attacking the peptidoglycan-virulence interconnection as a key weak point of the Gram-negative pathogens to be used, if not to kill the bacteria, to mitigate their capacity to produce severe infections.
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Affiliation(s)
- Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Isabel Maria Barceló
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
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21
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Lenz JD, Shirk KA, Jolicoeur A, Dillard JP. Selective Inhibition of Neisseria gonorrhoeae by a Dithiazoline in Mixed Infections with Lactobacillus gasseri. Antimicrob Agents Chemother 2018; 62:e00826-18. [PMID: 30275084 PMCID: PMC6256793 DOI: 10.1128/aac.00826-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/22/2018] [Indexed: 11/20/2022] Open
Abstract
The Gram-negative human pathogen Neisseria gonorrhoeae has progressively developed resistance to antibiotic monotherapies, and recent failures of dual-drug therapy have heightened concerns that strains resistant to all available antibiotics will begin circulating globally. Targeting bacterial cell wall assembly has historically been effective at treating infections with N. gonorrhoeae, but as the effectiveness of β-lactams (including cephalosporins) is challenged by increasing resistance, research has expanded into compounds that target the numerous other enzymes with roles in peptidoglycan metabolism. One example is the dithiazoline compound JNJ-853346 (DTZ), which inhibits the activity of an Escherichia coli serine protease l,d-carboxypeptidase (LdcA). Recently, the characterization of an LdcA homolog in N. gonorrhoeae revealed localization and activity differences from the characterized E. coli LdcA, prompting us to explore the effectiveness of DTZ against N. gonorrhoeae We found that DTZ is effective at inhibiting N. gonorrhoeae in all growth phases, unlike the specific stationary-phase inhibition seen in E. coli Surprisingly, DTZ does not inhibit gonococcal LdcA enzyme activity, and DTZ sensitivity is not significantly decreased in ldcA mutants. While effective against numerous N. gonorrhoeae strains, including recent multidrug-resistant isolates, DTZ is much less effective at inhibiting growth of the commensal species Lactobacillus gasseri DTZ treatment during coinfections of epithelial cells resulted in significant lowering of gonococcal burden and interleukin-8 secretion without significantly impacting recovery of viable L. gasseri This selective toxicity presents a possible pathway for the use of DTZ as an effective antigonococcal agent at concentrations that do not impact vaginal commensals.
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Affiliation(s)
- Jonathan D Lenz
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Kristina A Shirk
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Adrienne Jolicoeur
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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22
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Lenz JD, Dillard JP. Pathogenesis of Neisseria gonorrhoeae and the Host Defense in Ascending Infections of Human Fallopian Tube. Front Immunol 2018; 9:2710. [PMID: 30524442 PMCID: PMC6258741 DOI: 10.3389/fimmu.2018.02710] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/02/2018] [Indexed: 12/28/2022] Open
Abstract
Neisseria gonorrhoeae is an obligate human pathogen that causes mucosal surface infections of male and female reproductive tracts, pharynx, rectum, and conjunctiva. Asymptomatic or unnoticed infections in the lower reproductive tract of women can lead to serious, long-term consequences if these infections ascend into the fallopian tube. The damage caused by gonococcal infection and the subsequent inflammatory response produce the condition known as pelvic inflammatory disease (PID). Infection can lead to tubal scarring, occlusion of the oviduct, and loss of critical ciliated cells. Consequences of the damage sustained on the fallopian tube epithelium include increased risk of ectopic pregnancy and tubal-factor infertility. Additionally, the resolution of infection can produce new adhesions between internal tissues, which can tear and reform, producing chronic pelvic pain. As a bacterium adapted to life in a human host, the gonococcus presents a challenge to the development of model systems for probing host-microbe interactions. Advances in small-animal models have yielded previously unattainable data on systemic immune responses, but the specificity of N. gonorrhoeae for many known (and unknown) host targets remains a constant hurdle. Infections of human volunteers are possible, though they present ethical and logistical challenges, and are necessarily limited to males due to the risk of severe complications in women. It is routine, however, that normal, healthy fallopian tubes are removed in the course of different gynecological surgeries (namely hysterectomy), making the very tissue most consequentially damaged during ascending gonococcal infection available for laboratory research. The study of fallopian tube organ cultures has allowed the opportunity to observe gonococcal biology and immune responses in a complex, multi-layered tissue from a natural host. Forty-five years since the first published example of human fallopian tube being infected ex vivo with N. gonorrhoeae, we review what modeling infections in human tissue explants has taught us about the gonococcus, what we have learned about the defenses mounted by the human host in the upper female reproductive tract, what other fields have taught us about ciliated and non-ciliated cell development, and ultimately offer suggestions regarding the next generation of model systems to help expand our ability to study gonococcal pathogenesis.
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Affiliation(s)
- Jonathan D Lenz
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
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Antibiotic Targets in Gonococcal Cell Wall Metabolism. Antibiotics (Basel) 2018; 7:antibiotics7030064. [PMID: 30037076 PMCID: PMC6164560 DOI: 10.3390/antibiotics7030064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 12/14/2022] Open
Abstract
The peptidoglycan cell wall that encloses the bacterial cell and provides structural support and protection is remodeled by multiple enzymes that synthesize and cleave the polymer during growth. This essential and dynamic structure has been targeted by multiple antibiotics to treat gonococcal infections. Up until now, antibiotics have been used against the biosynthetic machinery and the therapeutic potential of inhibiting enzymatic activities involved in peptidoglycan breakdown has not been explored. Given the major antibiotic resistance problems we currently face, it is crucial to identify other possible targets that are key to maintaining cell integrity and contribute to disease development. This article reviews peptidoglycan as an antibiotic target, how N. gonorrhoeae has developed resistance to currently available antibiotics, and the potential of continuing to target this essential structure to combat gonococcal infections by attacking alternative enzymatic activities involved in cell wall modification and metabolism.
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Dik DA, Fisher JF, Mobashery S. Cell-Wall Recycling of the Gram-Negative Bacteria and the Nexus to Antibiotic Resistance. Chem Rev 2018; 118:5952-5984. [PMID: 29847102 PMCID: PMC6855303 DOI: 10.1021/acs.chemrev.8b00277] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The importance of the cell wall to the viability of the bacterium is underscored by the breadth of antibiotic structures that act by blocking key enzymes that are tasked with cell-wall creation, preservation, and regulation. The interplay between cell-wall integrity, and the summoning forth of resistance mechanisms to deactivate cell-wall-targeting antibiotics, involves exquisite orchestration among cell-wall synthesis and remodeling and the detection of and response to the antibiotics through modulation of gene regulation by specific effectors. Given the profound importance of antibiotics to the practice of medicine, the assertion that understanding this interplay is among the most fundamentally important questions in bacterial physiology is credible. The enigmatic regulation of the expression of the AmpC β-lactamase, a clinically significant and highly regulated resistance response of certain Gram-negative bacteria to the β-lactam antibiotics, is the exemplar of this challenge. This review gives a current perspective to this compelling, and still not fully solved, 35-year enigma.
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Affiliation(s)
- David A. Dik
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jed F. Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
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Meyer K, Addy C, Akashi S, Roper DI, Tame JR. The crystal structure and oligomeric form of Escherichia coli l , d -carboxypeptidase A. Biochem Biophys Res Commun 2018; 499:594-599. [DOI: 10.1016/j.bbrc.2018.03.195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 03/26/2018] [Indexed: 11/16/2022]
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