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Darwitz BP, Genito CJ, Thurlow LR. Triple threat: how diabetes results in worsened bacterial infections. Infect Immun 2024:e0050923. [PMID: 38526063 DOI: 10.1128/iai.00509-23] [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: 03/26/2024] Open
Abstract
Diabetes mellitus, characterized by impaired insulin signaling, is associated with increased incidence and severity of infections. Various diabetes-related complications contribute to exacerbated bacterial infections, including hyperglycemia, innate immune cell dysfunction, and infection with antibiotic-resistant bacterial strains. One defining symptom of diabetes is hyperglycemia, resulting in elevated blood and tissue glucose concentrations. Glucose is the preferred carbon source of several bacterial pathogens, and hyperglycemia escalates bacterial growth and virulence. Hyperglycemia promotes specific mechanisms of bacterial virulence known to contribute to infection chronicity, including tissue adherence and biofilm formation. Foot infections are a significant source of morbidity in individuals with diabetes and consist of biofilm-associated polymicrobial communities. Bacteria perform complex interspecies behaviors conducive to their growth and virulence within biofilms, including metabolic cross-feeding and altered phenotypes more tolerant to antibiotic therapeutics. Moreover, the metabolic dysfunction caused by diabetes compromises immune cell function, resulting in immune suppression. Impaired insulin signaling induces aberrations in phagocytic cells, which are crucial mediators for controlling and resolving bacterial infections. These aberrancies encompass altered cytokine profiles, the migratory and chemotactic mechanisms of neutrophils, and the metabolic reprogramming required for the oxidative burst and subsequent generation of bactericidal free radicals. Furthermore, the immune suppression caused by diabetes and the polymicrobial nature of the diabetic infection microenvironment may promote the emergence of novel strains of multidrug-resistant bacterial pathogens. This review focuses on the "triple threat" linked to worsened bacterial infections in individuals with diabetes: (i) altered nutritional availability in diabetic tissues, (ii) diabetes-associated immune suppression, and (iii) antibiotic treatment failure.
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Affiliation(s)
- Benjamin P Darwitz
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Christopher J Genito
- Division of Oral and Craniofacial Health Sciences, University of North Carolina at Chapel Hill Adams School of Dentistry, Chapel Hill, North Carolina, USA
| | - Lance R Thurlow
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
- Division of Oral and Craniofacial Health Sciences, University of North Carolina at Chapel Hill Adams School of Dentistry, Chapel Hill, North Carolina, USA
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Lo HY, Long DR, Holmes EA, Penewit K, Hodgson T, Lewis JD, Waalkes A, Salipante SJ. Transposon sequencing identifies genes impacting Staphylococcus aureus invasion in a human macrophage model. Infect Immun 2023; 91:e0022823. [PMID: 37676013 PMCID: PMC10580828 DOI: 10.1128/iai.00228-23] [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: 06/14/2023] [Accepted: 07/13/2023] [Indexed: 09/08/2023] Open
Abstract
Staphylococcus aureus is a facultative intracellular pathogen in many host cell types, facilitating its persistence in chronic infections. The genes contributing to intracellular pathogenesis have not yet been fully enumerated. Here, we cataloged genes influencing S. aureus invasion and survival within human THP-1 derived macrophages using two laboratory strains (ATCC2913 and JE2). We developed an in vitro transposition method to produce highly saturated transposon mutant libraries in S. aureus and performed transposon insertion sequencing (Tn-Seq) to identify candidate genes with significantly altered abundance following macrophage invasion. While some significant genes were strain-specific, 108 were identified as common across both S. aureus strains, with most (n = 106) being required for optimal macrophage infection. We used CRISPR interference (CRISPRi) to functionally validate phenotypic contributions for a subset of genes. Of the 20 genes passing validation, seven had previously identified roles in S. aureus virulence, and 13 were newly implicated. Validated genes frequently evidenced strain-specific effects, yielding opposing phenotypes when knocked down in the alternative strain. Genomic analysis of de novo mutations occurring in groups (n = 237) of clonally related S. aureus isolates from the airways of chronically infected individuals with cystic fibrosis (CF) revealed significantly greater in vivo purifying selection in conditionally essential candidate genes than those not associated with macrophage invasion. This study implicates a core set of genes necessary to support macrophage invasion by S. aureus, highlights strain-specific differences in phenotypic effects of effector genes, and provides evidence for selection of candidate genes identified by Tn-Seq analyses during chronic airway infection in CF patients in vivo.
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Affiliation(s)
- Hsin-Yu Lo
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Dustin R. Long
- Division of Critical Care Medicine, Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, Washington, USA
| | - Elizbeth A. Holmes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Kelsi Penewit
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Taylor Hodgson
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Janessa D. Lewis
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Adam Waalkes
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Stephen J. Salipante
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, Washington, USA
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A Manganese-independent Aldolase Enables Staphylococcus aureus To Resist Host-imposed Metal Starvation. mBio 2023; 14:e0322322. [PMID: 36598285 PMCID: PMC9973326 DOI: 10.1128/mbio.03223-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The preferred carbon source of Staphylococcus aureus and many other pathogens is glucose, and its consumption is critical during infection. However, glucose utilization increases the cellular demand for manganese, a nutrient sequestered by the host as a defense against invading pathogens. Therefore, bacteria must balance glucose metabolism with the increasing demand that metal-dependent processes, such as glycolysis, impose upon the cell. A critical regulator that enables S. aureus to resist nutritional immunity is the ArlRS two-component system. This work revealed that ArlRS regulates the expression of FdaB, a metal-independent fructose 1,6-bisphosphate aldolase. Further investigation revealed that when S. aureus is metal-starved by the host, FdaB functionally replaces the metal-dependent isozyme FbaA, thereby allowing S. aureus to resist host-imposed metal starvation in culture. Although metal-dependent aldolases are canonically zinc-dependent, this work uncovered that FbaA requires manganese for activity and that FdaB protects S. aureus from manganese starvation. Both FbaA and FdaB contribute to the ability of S. aureus to cause invasive disease in wild-type mice. However, the virulence defect of a strain lacking FdaB was reversed in calprotectin-deficient mice, which have defects in manganese sequestration, indicating that this isozyme contributes to the ability of this pathogen to overcome manganese limitation during infection. Cumulatively, these observations suggest that the expression of the metal-independent aldolase FdaB allows S. aureus to alleviate the increased demand for manganese that glucose consumption imposes, and highlights the cofactor flexibility of even established metalloenzyme families. IMPORTANCE Staphylococcus aureus and other pathogens consume glucose during infection. Glucose utilization increases the demand for transition metals, such as manganese, a nutrient that the host limits as a defense mechanism against invading pathogens. Therefore, pathogenic bacteria must balance glucose and manganese requirements during infection. The two-component system ArlRS is an important regulator that allows S. aureus to adapt to both glucose and manganese starvation. Among the genes regulated by ArlRS is the metal-independent fructose 1,6-bisphosphate aldolase fdaB, which functionally substitutes for the metal-dependent isoenzyme FbaA and enables S. aureus to survive host-imposed manganese starvation. Unexpectedly, and differing from most characterized metal-dependent aldolases, FbaA requires manganese for activity. Cumulatively, these findings reveal a new mechanism for overcoming nutritional immunity as well as the cofactor plasticity of even well-characterized metalloenzyme families.
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Jordan MR, Gonzalez-Gutierrez G, Trinidad JC, Giedroc DP. Metal retention and replacement in QueD2 protect queuosine-tRNA biosynthesis in metal-starved Acinetobacter baumannii. Proc Natl Acad Sci U S A 2022; 119:e2213630119. [PMID: 36442121 PMCID: PMC9894224 DOI: 10.1073/pnas.2213630119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 10/28/2022] [Indexed: 11/29/2022] Open
Abstract
In response to bacterial infection, the vertebrate host employs the metal-sequestering protein calprotectin (CP) to withhold essential transition metals, notably Zn(II), to inhibit bacterial growth. Previous studies of the impact of CP-imposed transition-metal starvation in A. baumannii identified two enzymes in the de novo biosynthesis pathway of queuosine-transfer ribonucleic acid (Q-tRNA) that become cellularly abundant, one of which is QueD2, a 6-carboxy-5,6,7,8-tetrahydropterin (6-CPH4) synthase that catalyzes the initial, committed step of the pathway. Here, we show that CP strongly disrupts Q incorporation into tRNA. As such, we compare the AbQueD2 "low-zinc" paralog with a housekeeping, obligatory Zn(II)-dependent enzyme QueD. The crystallographic structure of Zn(II)-bound AbQueD2 reveals a distinct catalytic site coordination sphere and assembly state relative to QueD and possesses a dynamic loop, immediately adjacent to the catalytic site that coordinates a second Zn(II) in the structure. One of these loop-coordinating residues is an invariant Cys18, that protects QueD2 from dissociation of the catalytic Zn(II) while maintaining flux through the Q-tRNA biosynthesis pathway in cells. We propose a "metal retention" model where Cys18 introduces coordinative plasticity into the catalytic site which slows metal release, while also enhancing the metal promiscuity such that Fe(II) becomes an active cofactor. These studies reveal a complex, multipronged evolutionary adaptation to cellular Zn(II) limitation in a key Zn(II) metalloenzyme in an important human pathogen.
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Affiliation(s)
- Matthew R. Jordan
- Department of Chemistry, Indiana University, Bloomington, IN47405
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN47405
| | | | - Jonathan C. Trinidad
- Department of Chemistry, Indiana University, Bloomington, IN47405
- Laboratory for Biological Mass Spectrometry, Department of Chemistry, Indiana University, Bloomington, IN47405
| | - David P. Giedroc
- Department of Chemistry, Indiana University, Bloomington, IN47405
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Lee J, Lee J, Cho Y, Choi J, Han SW. A putative 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase is involved in the virulence, carbohydrate metabolism, biofilm formation, twitching halo, and osmotic tolerance in Acidovorax citrulli. FRONTIERS IN PLANT SCIENCE 2022; 13:1039420. [PMID: 36438092 PMCID: PMC9681784 DOI: 10.3389/fpls.2022.1039420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/14/2022] [Indexed: 06/16/2023]
Abstract
Acidovorax citrulli (Ac) is a gram-negative bacterium that causes bacterial fruit blotch (BFB) disease in cucurbit crops including watermelon. However, despite the great economic losses caused by this disease worldwide, Ac-resistant watermelon cultivars have not been developed. Therefore, characterizing the virulence factors/mechanisms of Ac would enable the development of effective control strategies against BFB disease. The 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase (BdpM) is known to participate in the glycolysis and gluconeogenesis pathways. However, the roles of the protein have not been characterized in Ac. To elucidate the functions of BdpmAc (Bdpm in Ac), comparative proteomic analysis and diverse phenotypic assays were conducted using a bdpmAc knockout mutant (bdpmAc:Tn) and a wild-type strain. The virulence of the mutant to watermelon was remarkably reduced in both germinated seed inoculation and leaf infiltration assays. Moreover, the mutant could not grow with fructose or pyruvate as a sole carbon source. However, the growth of the mutant was restored to levels similar to those of the wild-type strain in the presence of both fructose and pyruvate. Comparative proteomic analyses revealed that diverse proteins involved in motility and wall/membrane/envelop biogenesis were differentially abundant. Furthermore, the mutant exhibited decreased biofilm formation and twitching halo size. Interestingly, the mutant exhibited a higher tolerance against osmotic stress. Overall, our findings suggest that BdpmAc affects the virulence, glycolysis/gluconeogenesis, biofilm formation, twitching halo size, and osmotic tolerance of Ac, suggesting that this protein has pleiotropic properties. Collectively, our findings provide fundamental insights into the functions of a previously uncharacterized phosphoglycerate mutase in Ac.
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Roth M, Goodall ECA, Pullela K, Jaquet V, François P, Henderson IR, Krause KH. Transposon-Directed Insertion-Site Sequencing Reveals Glycolysis Gene gpmA as Part of the H2O2 Defense Mechanisms in Escherichia coli. Antioxidants (Basel) 2022; 11:antiox11102053. [PMID: 36290776 PMCID: PMC9598634 DOI: 10.3390/antiox11102053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/16/2022] Open
Abstract
Hydrogen peroxide (H2O2) is a common effector of defense mechanisms against pathogenic infections. However, bacterial factors involved in H2O2 tolerance remain unclear. Here we used transposon-directed insertion-site sequencing (TraDIS), a technique allowing the screening of the whole genome, to identify genes implicated in H2O2 tolerance in Escherichia coli. Our TraDIS analysis identified 10 mutants with fitness defect upon H2O2 exposure, among which previously H2O2-associated genes (oxyR, dps, dksA, rpoS, hfq and polA) and other genes with no known association with H2O2 tolerance in E. coli (corA, rbsR, nhaA and gpmA). This is the first description of the impact of gpmA, a gene involved in glycolysis, on the susceptibility of E. coli to H2O2. Indeed, confirmatory experiments showed that the deletion of gpmA led to a specific hypersensitivity to H2O2 comparable to the deletion of the major H2O2 scavenger gene katG. This hypersensitivity was not due to an alteration of catalase function and was independent of the carbon source or the presence of oxygen. Transcription of gpmA was upregulated under H2O2 exposure, highlighting its role under oxidative stress. In summary, our TraDIS approach identified gpmA as a member of the oxidative stress defense mechanism in E. coli.
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Affiliation(s)
- Myriam Roth
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
- Correspondence:
| | - Emily C. A. Goodall
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Karthik Pullela
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Vincent Jaquet
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
- READS Unit, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
| | - Patrice François
- Genomic Research Laboratory, Infectious Diseases Service, University Hospitals of Geneva, University Medical Center, Michel-Servet 1, 1211 Geneva, Switzerland
| | - Ian R. Henderson
- Institute for Molecular Bioscience, University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Karl-Heinz Krause
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
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Potok P, Potocki S. Bacterial M10 metallopeptidase as a medicinal target - coordination chemistry of possible metal-based inhibition. Dalton Trans 2022; 51:14882-14893. [PMID: 36056680 DOI: 10.1039/d2dt02265f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Streptococcus pneumoniae is the most frequent cause of fatal bacterial pneumonia infection worldwide. Due to the spreading of antibiotic-resistant pathogens, it is important to search for new therapeutic and prevention strategies against bacterial infections. It is believed that the search for effective inhibitors of bacterial and pathogenic metallopeptidases could be one of the innovative strategies for the design of new antibiotics. Most of them contain zinc in the metal-binding site of the protein, which is a critical component for the biological activity of the enzyme. The main goal of this work is to determine the specificity of the interactions between the binding domain of the metallopeptidase from S. pneumoniae, and Zn(II). Considering the observed inhibitory role of copper towards the metallopeptidases, the next step is to analyze the formation of complexes with Cu(II) and Ni(II). The thermodynamic properties of Zn(II), Cu(II), and Ni(II) complexes were examined by potentiometry, NMR, MS, UV-Vis, CD, and EPR. The results show a similar coordination pattern, HExxHxxxxxH, for all three studied metals below pH 7. Moreover, the primary binding sites were established as the N-terminus in all cases. However, at a pH value of 7.4, the coordination and geometry of the formed complexes differ. The comparison of the stability of the formed complexes reveals that both Cu(II) and Ni(II) are able to displace Zn(II) from its binding site in the whole studied pH range. It opens a discussion on the catalytic zinc ion displacement possibilities by other divalent metal ions and the importance of this process in enzymatic inhibition.
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Affiliation(s)
- Paulina Potok
- Faculty of Chemistry, University of Wroclaw, 14 Joliot-Curie St., 50-383 Wroclaw, Poland.
| | - Sławomir Potocki
- Faculty of Chemistry, University of Wroclaw, 14 Joliot-Curie St., 50-383 Wroclaw, Poland.
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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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Uppalapati SR, Vazquez-Torres A. Manganese Utilization in Salmonella Pathogenesis: Beyond the Canonical Antioxidant Response. Front Cell Dev Biol 2022; 10:924925. [PMID: 35903545 PMCID: PMC9315381 DOI: 10.3389/fcell.2022.924925] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/22/2022] [Indexed: 11/16/2022] Open
Abstract
The metal ion manganese (Mn2+) is equally coveted by hosts and bacterial pathogens. The host restricts Mn2+ in the gastrointestinal tract and Salmonella-containing vacuoles, as part of a process generally known as nutritional immunity. Salmonella enterica serovar Typhimurium counteract Mn2+ limitation using a plethora of metal importers, whose expression is under elaborate transcriptional and posttranscriptional control. Mn2+ serves as cofactor for a variety of enzymes involved in antioxidant defense or central metabolism. Because of its thermodynamic stability and low reactivity, bacterial pathogens may favor Mn2+-cofactored metalloenzymes during periods of oxidative stress. This divalent metal catalyzes metabolic flow through lower glycolysis, reductive tricarboxylic acid and the pentose phosphate pathway, thereby providing energetic, redox and biosynthetic outputs associated with the resistance of Salmonella to reactive oxygen species generated in the respiratory burst of professional phagocytic cells. Combined, the oxyradical-detoxifying properties of Mn2+ together with the ability of this divalent metal cation to support central metabolism help Salmonella colonize the mammalian gut and establish systemic infections.
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Affiliation(s)
- Siva R. Uppalapati
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO, United States,*Correspondence: Siva R. Uppalapati, ; Andres Vazquez-Torres,
| | - Andres Vazquez-Torres
- Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, CO, United States,Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States,*Correspondence: Siva R. Uppalapati, ; Andres Vazquez-Torres,
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Hosseini Dastgerdi A, Ghanbari Rad M, Soltani N. The Therapeutic Effects of Magnesium in Insulin Secretion and Insulin Resistance. Adv Biomed Res 2022; 11:54. [PMID: 35982863 PMCID: PMC9379913 DOI: 10.4103/abr.abr_366_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/26/2022] [Accepted: 02/08/2022] [Indexed: 11/09/2022] Open
Abstract
Insulin resistance (IR) is a chronic pathological condition that is related to reduce the rates of glucose uptake, especially in the liver, muscle, and adipose tissue as target tissues. Metabolic syndrome and type 2 diabetes mellitus can occur following progression of the disease. The majority of prior research has applied that some cations such as magnesium (Mg2+) have important physiological role in insulin metabolism. Mg2+ is the fourth most abundant mineral in the human body that gets involved as a cofactor of various enzymes in several metabolic events, such as carbohydrate oxidation, and it has a fundamental role in glucose transporting mechanism of the cell membrane. This cation has numerous duties in the human body such as regulation of insulin secretion in pancreatic beta-cells and phosphorylation of the insulin receptors in target cells and also gets involved in other downstream signal kinases as intracellular cation. On this basis, intracellular Mg2+ balancing is vital for adequate carbohydrate metabolism. This paper summarizes the present knowledge about the therapeutic effects of Mg2+ in reducing IR in liver, muscle, and pancreases with different mechanisms. For this, the search was performed in Google Scholar, PubMed, Scopus, and Web of Science by insulin resistance, skeletal muscle, liver, pancreases, magnesium, Mg2+, and inflammation keywords.
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Affiliation(s)
| | - Mahtab Ghanbari Rad
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Nepton Soltani
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran,Address for correspondence: Prof. Nepton Soltani, Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. E-mail:
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van Dijk MC, de Kruijff RM, Hagedoorn PL. The Role of Iron in Staphylococcus aureus Infection and Human Disease: A Metal Tug of War at the Host—Microbe Interface. Front Cell Dev Biol 2022; 10:857237. [PMID: 35399529 PMCID: PMC8986978 DOI: 10.3389/fcell.2022.857237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 02/24/2022] [Indexed: 11/27/2022] Open
Abstract
Iron deficiency anemia can be treated with oral or intravenous Fe supplementation. Such supplementation has considerable effects on the human microbiome, and on opportunistic pathogenic micro-organisms. Molecular understanding of the control and regulation of Fe availability at the host-microbe interface is crucial to interpreting the side effects of Fe supplementation. Here, we provide a concise overview of the regulation of Fe by the opportunistic pathogen Staphylococcus aureus. Ferric uptake regulator (Fur) plays a central role in controlling Fe uptake, utilization and storage in order to maintain a required value. The micro-organism has a strong preference for heme iron as an Fe source, which is enabled by the Iron-regulated surface determinant (Isd) system. The strategies it employs to overcome Fe restriction imposed by the host include: hijacking host proteins, replacing metal cofactors, and replacing functions by non-metal dependent enzymes. We propose that integrated omics approaches, which include metalloproteomics, are necessary to provide a comprehensive understanding of the metal tug of war at the host-microbe interface down to the molecular level.
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Affiliation(s)
- Madeleine C. van Dijk
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
- Department of Radiation Science and Technology, Delft University of Technology, Delft, Netherlands
| | - Robin M. de Kruijff
- Department of Radiation Science and Technology, Delft University of Technology, Delft, Netherlands
- *Correspondence: Robin M. de Kruijff, ; Peter-Leon Hagedoorn,
| | - Peter-Leon Hagedoorn
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
- *Correspondence: Robin M. de Kruijff, ; Peter-Leon Hagedoorn,
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He R, Wang J, Lin M, Tian J, Wu B, Tan X, Zhou J, Zhang J, Yan Q, Huang L. Effect of Ferredoxin Receptor FusA on the Virulence Mechanism of Pseudomonas plecoglossicida. Front Cell Infect Microbiol 2022; 12:808800. [PMID: 35392610 PMCID: PMC8981516 DOI: 10.3389/fcimb.2022.808800] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/17/2022] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas plecoglossicida is an aerobic Gram-negative bacterium, which is the pathogen of “Visceral white spot disease” in large yellow croaker. P. plecoglossicida is a temperature-dependent bacterial pathogen in fish, which not only reduces the yield of large yellow croaker but also causes continuous transmission of the disease, seriously endangering the healthy development of fisheries. In this study, a mutant strain of fusA was constructed using homologous recombination technology. The results showed that knockout of P. plecoglossicida fusA significantly affected the ability of growth, adhesion, and biofilm formation. Temperature, pH, H2O2, heavy metals, and the iron-chelating agent were used to treat the wild type of P. plecoglossicida; the results showed that the expression of fusA was significantly reduced at 4°C, 12°C, and 37°C. The expression of fusA was significantly increased at pH 4 and 5. Cu2+ has a significant inducing effect on the expression of fusA, but Pb2+ has no obvious effect; the expression of fusA was significantly upregulated under different concentrations of H2O2. The expression of the fusA gene was significantly upregulated in the 0.5~4-μmol/l iron-chelating agent. The expression level of the fusA gene was significantly upregulated after the logarithmic phase. It was suggested that fusA included in the TBDR family not only was involved in the transport of ferredoxin but also played important roles in the pathogenicity and environment adaptation of P. plecoglossicida.
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Affiliation(s)
- Rongchao He
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jiajia Wang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Miaozhen Lin
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jing Tian
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Bi Wu
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Xiaohan Tan
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Jianchuan Zhou
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
| | - Jiachen Zhang
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Qingpi Yan
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
- *Correspondence: Qingpi Yan, ; Lixing Huang,
| | - Lixing Huang
- Fisheries College, Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Jimei University, Xiamen, China
- *Correspondence: Qingpi Yan, ; Lixing Huang,
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Lakshmi SA, Prasath KG, Tamilmuhilan K, Srivathsan A, Shafreen RMB, Kasthuri T, Pandian SK. Suppression of Thiol-Dependent Antioxidant System and Stress Response in Methicillin-Resistant Staphylococcus aureus by Docosanol: Explication Through Proteome Investigation. Mol Biotechnol 2022; 64:575-589. [PMID: 35018617 DOI: 10.1007/s12033-021-00434-4] [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: 07/27/2021] [Accepted: 12/01/2021] [Indexed: 11/28/2022]
Abstract
The present study was aimed to investigate the effect of docosanol on the protein expression profile of methicillin-resistant Staphylococcus aureus (MRSA). Thus, two-dimensional gel electrophoresis coupled with MALDI-TOF MS technique was utilized to identify the differentially regulated proteins in the presence of docosanol. A total of 947 protein spots were identified from the intracellular proteome of both control and docosanol treated samples among which 40 spots were differentially regulated with a fold change greater than 1.0. Prominently, the thiol-dependent antioxidant system and stress response proteins are downregulated in MRSA, which are critical for survival during oxidative stress. In particular, docosanol downregulated the expression of Tpx, AhpC, BshC, BrxA, and YceI with a fold change of 1.4 (p = 0.02), 1.4 (p = 0.01), 1.6 (p = 0.002), 4.9 (p = 0.02), and 1.4 (p = 0.02), respectively. In addition, docosanol reduced the expression of proteins involved in purine metabolic pathways, biofilm growth cycle, and virulence factor production. Altogether, these findings suggest that docosanol could efficiently target the antioxidant pathway by reducing the expression of bacillithiol and stress-associated proteins.
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Affiliation(s)
- Selvaraj Alagu Lakshmi
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
| | - Krishnan Ganesh Prasath
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
- Department of Biotechnology, Sri Venkateswara College of Engineering, Sriperumbudur, Tamil Nadu, 602117, India
| | - Kannapiran Tamilmuhilan
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
| | - Adimoolam Srivathsan
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
| | - Raja Mohamed Beema Shafreen
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
- Department of Biotechnology, Dr. Umayal Ramanathan College for Women, Alagappapuram, Karaikudi, Tamil Nadu, 630003, India
| | - Thirupathi Kasthuri
- Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India
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14
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Smethurst DGJ, Shcherbik N. Interchangeable utilization of metals: New perspectives on the impacts of metal ions employed in ancient and extant biomolecules. J Biol Chem 2021; 297:101374. [PMID: 34732319 PMCID: PMC8633580 DOI: 10.1016/j.jbc.2021.101374] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 02/08/2023] Open
Abstract
Metal ions provide considerable functionality across biological systems, and their utilization within biomolecules has adapted through changes in the chemical environment to maintain the activity they facilitate. While ancient earth's atmosphere was rich in iron and manganese and low in oxygen, periods of atmospheric oxygenation significantly altered the availability of certain metal ions, resulting in ion replacement within biomolecules. This adaptation mechanism has given rise to the phenomenon of metal cofactor interchangeability, whereby contemporary proteins and nucleic acids interact with multiple metal ions interchangeably, with different coordinated metals influencing biological activity, stability, and toxic potential. The ability of extant organisms to adapt to fluctuating metal availability remains relevant in a number of crucial biomolecules, including the superoxide dismutases of the antioxidant defense systems and ribonucleotide reductases. These well-studied and ancient enzymes illustrate the potential for metal interchangeability and adaptive utilization. More recently, the ribosome has also been demonstrated to exhibit interchangeable interactions with metal ions with impacts on function, stability, and stress adaptation. Using these and other examples, here we review the biological significance of interchangeable metal ions from a new angle that combines both biochemical and evolutionary viewpoints. The geochemical pressures and chemical properties that underlie biological metal utilization are discussed in the context of their impact on modern disease states and treatments.
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Affiliation(s)
- Daniel G J Smethurst
- Department for Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, USA.
| | - Natalia Shcherbik
- Department for Cell Biology and Neuroscience, School of Osteopathic Medicine, Rowan University, Stratford, New Jersey, USA.
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15
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Abstract
Iron (Fe) plays important roles in both essential cellular processes and virulence pathways for many bacteria. Consequently, Fe withholding by the human innate immune system is an effective form of defense against bacterial infection. In this Perspective, we review recent studies that have established a foundation for our understanding of the impact of the metal-sequestering host defense protein calprotectin (CP) on bacterial Fe homeostasis. We also discuss two recently uncovered strategies for bacterial adaptation to Fe withholding by CP. Together, these studies provide insight into how Fe sequestration by CP affects bacterial pathogens that include Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. Overall, recent studies suggest that Fe withholding by CP may have implications for bacterial survival and virulence in the host, and further explorations that directly address this possibility present an important area for discovery.
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Affiliation(s)
- Adunoluwa O. Obisesan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Emily M. Zygiel
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Elizabeth M. Nolan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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16
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Yang H, Yao S, Zhang M, Wu C. Heat Adaptation Induced Cross Protection Against Ethanol Stress in Tetragenococcus halophilus: Physiological Characteristics and Proteomic Analysis. Front Microbiol 2021; 12:686672. [PMID: 34220775 PMCID: PMC8249775 DOI: 10.3389/fmicb.2021.686672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 05/03/2021] [Indexed: 11/29/2022] Open
Abstract
Ethanol is a toxic factor that damages membranes, disturbs metabolism, and may kill the cell. Tetragenococcus halophilus, considered as the cell factory during the manufacture of traditional fermented foods, encounters ethanol stress, which may affect the viability and fermentative performance of cells. In order to improve the ethanol tolerance of T. halophilus, a strategy based on cross protection was proposed in the current study. The results indicated that cross protection induced by heat preadaptation (45°C for 1.5 h) could significantly improve the stress tolerance (7.24-fold increase in survival) of T. halophilus upon exposure to ethanol (10% for 2.5 h). Based on this result, a combined analysis of physiological approaches and TMT-labeled proteomic technology was employed to investigate the protective mechanism of cross protection in T. halophilus. Physiological analysis showed that the heat preadapted cells exhibited a better surface phenotype, higher membrane integrity, and higher amounts of unsaturated fatty acids compared to unadapted cells. Proteomic analysis showed that a total of 163 proteins were differentially expressed in response to heat preadaptation. KEGG enrichment analysis showed that energy metabolism, membrane transport, peptidoglycan biosynthesis, and genetic information processing were the most abundant metabolic pathways after heat preadaptation. Three proteins (GpmA, AtpB, and TpiA) involved in energy metabolism and four proteins (ManM, OpuC, YidC, and HPr) related to membrane transport were up-regulated after heat preadaptation. In all, the results of this study may help understand the protective mechanisms of preadaptation and contribute to the improvement of the stress resistance of T. halophilus during industrial processes.
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Affiliation(s)
- Huan Yang
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Shangjie Yao
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Min Zhang
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
| | - Chongde Wu
- College of Biomass Science and Engineering, Sichuan University, Chengdu, China.,Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu, China
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17
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Serafini A. Interplay between central carbon metabolism and metal homeostasis in mycobacteria and other human pathogens. MICROBIOLOGY (READING, ENGLAND) 2021; 167. [PMID: 34080971 DOI: 10.1099/mic.0.001060] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacterial nutrition is a fundamental aspect of pathogenesis. While the host environment is in principle nutrient-rich, hosts have evolved strategies to interfere with nutrient acquisition by pathogens. In turn, pathogens have developed mechanisms to circumvent these restrictions. Changing the availability of bioavailable metal ions is a common strategy used by hosts to limit bacterial replication. Macrophages and neutrophils withhold iron, manganese, and zinc ions to starve bacteria. Alternatively, they can release manganese, zinc, and copper ions to intoxicate microorganisms. Metals are essential micronutrients and participate in catalysis, macromolecular structure, and signalling. This review summarises our current understanding of how central carbon metabolism in pathogens adapts to local fluctuations in free metal ion concentrations. We focus on the transcriptomics and proteomics data produced in studies of the iron-sparing response in Mycobacterium tuberculosis, the etiological agent of tuberculosis, and consequently generate a hypothetical model linking trehalose accumulation, succinate secretion and substrate-level phosphorylation in iron-starved M. tuberculosis. This review also aims to highlight a large gap in our knowledge of pathogen physiology: the interplay between metal homeostasis and central carbon metabolism, two cellular processes which are usually studied separately. Integrating metabolism and metal biology would allow the discovery of new weaknesses in bacterial physiology, leading to the development of novel and improved antibacterial therapies.
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Affiliation(s)
- Agnese Serafini
- Independent researcher 00012 Guidonia Montecelio, Rome, Italy
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18
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Bosma EF, Rau MH, van Gijtenbeek LA, Siedler S. Regulation and distinct physiological roles of manganese in bacteria. FEMS Microbiol Rev 2021; 45:6284802. [PMID: 34037759 PMCID: PMC8632737 DOI: 10.1093/femsre/fuab028] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
Manganese (Mn2+) is an essential trace element within organisms spanning the entire tree of life. In this review, we provide an overview of Mn2+ transport and the regulation of its homeostasis in bacteria, with a focus on its functions beyond being a cofactor for enzymes. Crucial differences in Mn2+ homeostasis exist between bacterial species that can be characterized to have an iron- or manganese-centric metabolism. Highly iron-centric species require minimal Mn2+ and mostly use it as a mechanism to cope with oxidative stress. As a consequence, tight regulation of Mn2+ uptake is required, while organisms that use both Fe2+ and Mn2+ need other layers of regulation for maintaining homeostasis. We will focus in detail on manganese-centric bacterial species, in particular lactobacilli, that require little to no Fe2+ and use Mn2+ for a wider variety of functions. These organisms can accumulate extraordinarily high amounts of Mn2+ intracellularly, enabling the nonenzymatic use of Mn2+ for decomposition of reactive oxygen species while simultaneously functioning as a mechanism of competitive exclusion. We further discuss how Mn2+ accumulation can provide both beneficial and pathogenic bacteria with advantages in thriving in their niches.
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Affiliation(s)
- Elleke F Bosma
- Chr. Hansen A/S, Discovery, R&D, 2970 Hoersholm, Denmark
| | - Martin H Rau
- Chr. Hansen A/S, Discovery, R&D, 2970 Hoersholm, Denmark
| | | | - Solvej Siedler
- Corresponding author: Boege Allé 10-12, 2970 Hoersholm, Denmark. Tel: +45 52 18 08 25; E-mail:
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19
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Who's in control? Regulation of metabolism and pathogenesis in space and time. Curr Opin Microbiol 2020; 55:88-96. [PMID: 32532689 DOI: 10.1016/j.mib.2020.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/04/2020] [Accepted: 05/15/2020] [Indexed: 02/07/2023]
Abstract
Bacterial pathogens need to sense and respond to their environments during infection to align cell metabolism and virulence factor production to survive and battle host defenses. Complex regulatory networks including ligand-binding transcription factors, two-component systems, RNA-binding proteins, and small non-coding regulatory RNAs adjust gene expression programs in response to changes in metabolic fluxes, environmental cues, and nutrient availability. Recent studies underlined that these different layers of regulation occur along varying spatial and temporal scales, leading to changes in cell behavior and heterogeneity among the bacterial community. This brief review will highlight current research emphasizing that cell metabolism and pathogenesis are inextricably intertwined in both Gram-positive and Gram-negative bacteria.
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20
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Targeted Metabolomics Revealed the Regulatory Role of Manganese on Small-Molecule Metabolism of Biofilm Formation in Escherichia coli. JOURNAL OF ANALYSIS AND TESTING 2020. [DOI: 10.1007/s41664-020-00139-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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21
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Disruption of Phosphate Homeostasis Sensitizes Staphylococcus aureus to Nutritional Immunity. Infect Immun 2020; 88:IAI.00102-20. [PMID: 32205403 DOI: 10.1128/iai.00102-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 03/16/2020] [Indexed: 12/12/2022] Open
Abstract
To control infection, mammals actively withhold essential nutrients, including the transition metal manganese, by a process termed nutritional immunity. A critical component of this host response is the manganese-chelating protein calprotectin. While many bacterial mechanisms for overcoming nutritional immunity have been identified, the intersection between metal starvation and other essential inorganic nutrients has not been investigated. Here, we report that overexpression of an operon encoding a highly conserved inorganic phosphate importer, PstSCAB, increases the sensitivity of Staphylococcus aureus to calprotectin-mediated manganese sequestration. Further analysis revealed that overexpression of pstSCAB does not disrupt manganese acquisition or result in overaccumulation of phosphate by S. aureus However, it does reduce the ability of S. aureus to grow in phosphate-replete defined medium. Overexpression of pstSCAB does not aberrantly activate the phosphate-responsive two-component system PhoPR, nor was this two-component system required for sensitivity to manganese starvation. In a mouse model of systemic staphylococcal disease, a pstSCAB-overexpressing strain is significantly attenuated compared to wild-type S. aureus This defect is partially reversed in a calprotectin-deficient mouse, in which manganese is more readily available. Given that expression of pstSCAB is regulated by PhoPR, these findings suggest that overactivation of PhoPR would diminish the ability of S. aureus to resist nutritional immunity and cause infection. As PhoPR is also necessary for bacterial virulence, these findings imply that phosphate homeostasis represents a critical regulatory node whose activity must be precisely controlled in order for S. aureus and other pathogens to cause infection.
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22
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Jordan MR, Wang J, Capdevila DA, Giedroc DP. Multi-metal nutrient restriction and crosstalk in metallostasis systems in microbial pathogens. Curr Opin Microbiol 2020; 55:17-25. [PMID: 32062305 DOI: 10.1016/j.mib.2020.01.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/03/2020] [Accepted: 01/09/2020] [Indexed: 12/26/2022]
Abstract
Transition metals from manganese to zinc function as catalytic and structural cofactors for an amazing diversity of proteins and enzymes, and thus are essential for all forms of life. During infection, inflammatory host proteins limit the accessibility of multiple transition metals to invading pathogens in a process termed nutritional immunity. In order to respond to host-mediated metal starvation, bacteria employ both protein and RNA-based mechanisms to sense prevailing transition metal concentrations that collectively regulate systems-level strategies to maintain cellular metallostasis. In this review, we discuss a number of recent advances in our understanding of how bacteria orchestrate the adaptive response to host-mediated multi-metal restriction, highlighting crosstalk among these regulatory systems.
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Affiliation(s)
- Matthew R Jordan
- Departments of Chemistry and of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States
| | - Jiefei Wang
- Departments of Chemistry and of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States
| | - Daiana A Capdevila
- Fundación Instituto Leloir, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina
| | - David P Giedroc
- Departments of Chemistry and of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, United States.
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23
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Bacillus subtilis TerC Family Proteins Help Prevent Manganese Intoxication. J Bacteriol 2020; 202:JB.00624-19. [PMID: 31685536 DOI: 10.1128/jb.00624-19] [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: 09/30/2019] [Accepted: 10/29/2019] [Indexed: 12/24/2022] Open
Abstract
Manganese (Mn) is an essential element and is required for the virulence of many pathogens. In Bacillus subtilis, Mn(II) homeostasis is regulated by MntR, a Mn(II)-responsive, DNA-binding protein. MntR serves as both a repressor of Mn(II) uptake transporters and as a transcriptional activator for expression of two cation diffusion facilitator Mn(II) efflux pumps, MneP and MneS. Mutants lacking either mntR or both mneP and mneS are extremely sensitive to Mn(II) intoxication. Using transposon mutagenesis to select suppressors of Mn(II) sensitivity, we identified YceF, a TerC family membrane protein, as capable of providing Mn(II) resistance. Another TerC paralog, YkoY, is regulated by a Mn(II)-sensing riboswitch and is partially redundant in function with YceF. YkoY is regulated in parallel with an unknown function protein YybP, also controlled by a Mn(II)-sensing riboswitch. Strains lacking between one and five of these known or putative Mn(II) tolerance proteins (MneP, MneS, YceF, YkoY, and YybP) were tested for sensitivity to Mn(II) in growth assays and for accumulation of Mn(II) using inductively coupled plasma mass spectrometry. Loss of YceF and, to a lesser extent, YkoY, sensitizes cells lacking the MneP and MneS efflux transporters to Mn(II) intoxication. This sensitivity correlates with elevated intracellular Mn(II), consistent with the suggestion that TerC proteins function in Mn(II) efflux.IMPORTANCE Manganese homeostasis is primarily regulated at the level of transport. Bacillus subtilis MntR serves as a Mn(II)-activated repressor of importer genes (mntH and mntABC) and an activator of efflux genes (mneP and mneS). Elevated intracellular Mn(II) also binds to Mn-sensing riboswitches to activate transcription of yybP and ykoY, which encodes a TerC family member. Here, we demonstrate that two TerC family proteins, YceF and YkoY, help prevent Mn(II) intoxication. TerC family proteins are widespread in bacteria and may influence host-pathogen interactions, but their effects on Mn(II) homeostasis are unclear. Our results suggest that TerC proteins work by Mn(II) export under Mn(II) overload conditions to help alleviate toxicity.
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