Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress
ABSTRACT Nutritional immunity is an elegant host mechanism used to starve invading pathogens of necessary nutrient metals. Calprotectin, a metal-binding protein, is produced abundantly by neutrophils and is found in high concentrations within inflammatory sites during infection. Group B Streptococcu...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2020-12-01
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| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mBio.02302-20 |
| _version_ | 1818822621091856384 |
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| author | Lindsey R. Burcham Yoann Le Breton Jana N. Radin Brady L. Spencer Liwen Deng Aurélia Hiron Monica R. Ransom Jéssica da C. Mendonça Ashton T. Belew Najib M. El-Sayed Kevin S. McIver Thomas E. Kehl-Fie Kelly S. Doran |
| author_facet | Lindsey R. Burcham Yoann Le Breton Jana N. Radin Brady L. Spencer Liwen Deng Aurélia Hiron Monica R. Ransom Jéssica da C. Mendonça Ashton T. Belew Najib M. El-Sayed Kevin S. McIver Thomas E. Kehl-Fie Kelly S. Doran |
| author_sort | Lindsey R. Burcham |
| collection | DOAJ |
| description | ABSTRACT Nutritional immunity is an elegant host mechanism used to starve invading pathogens of necessary nutrient metals. Calprotectin, a metal-binding protein, is produced abundantly by neutrophils and is found in high concentrations within inflammatory sites during infection. Group B Streptococcus (GBS) colonizes the gastrointestinal and female reproductive tracts and is commonly associated with severe invasive infections in newborns such as pneumonia, sepsis, and meningitis. Although GBS infections induce robust neutrophil recruitment and inflammation, the dynamics of GBS and calprotectin interactions remain unknown. Here, we demonstrate that disease and colonizing isolate strains exhibit susceptibility to metal starvation by calprotectin. We constructed a mariner transposon (Krmit) mutant library in GBS and identified 258 genes that contribute to surviving calprotectin stress. Nearly 20% of all underrepresented mutants following treatment with calprotectin are predicted metal transporters, including known zinc systems. As calprotectin binds zinc with picomolar affinity, we investigated the contribution of GBS zinc uptake to overcoming calprotectin-imposed starvation. Quantitative reverse transcriptase PCR (qRT-PCR) revealed a significant upregulation of genes encoding zinc-binding proteins, adcA, adcAII, and lmb, following calprotectin exposure, while growth in calprotectin revealed a significant defect for a global zinc acquisition mutant (ΔadcAΔadcAIIΔlmb) compared to growth of the GBS wild-type (WT) strain. Furthermore, mice challenged with the ΔadcAΔadcAIIΔlmb mutant exhibited decreased mortality and significantly reduced bacterial burden in the brain compared to mice infected with WT GBS; this difference was abrogated in calprotectin knockout mice. Collectively, these data suggest that GBS zinc transport machinery is important for combatting zinc chelation by calprotectin and establishing invasive disease. IMPORTANCE Group B Streptococcus (GBS) asymptomatically colonizes the female reproductive tract but is a common causative agent of meningitis. GBS meningitis is characterized by extensive infiltration of neutrophils carrying high concentrations of calprotectin, a metal chelator. To persist within inflammatory sites and cause invasive disease, GBS must circumvent host starvation attempts. Here, we identified global requirements for GBS survival during calprotectin challenge, including known and putative systems involved in metal ion transport. We characterized the role of zinc import in tolerating calprotectin stress in vitro and in a mouse model of infection. We observed that a global zinc uptake mutant was less virulent than the parental GBS strain and found calprotectin knockout mice to be equally susceptible to infection by wild-type (WT) and mutant strains. These findings suggest that calprotectin production at the site of infection results in a zinc-limited environment and reveals the importance of GBS metal homeostasis to invasive disease. |
| first_indexed | 2024-12-18T23:26:59Z |
| format | Article |
| id | doaj.art-d67d2f2522254a81b3f4b51a434b7931 |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-12-18T23:26:59Z |
| publishDate | 2020-12-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-d67d2f2522254a81b3f4b51a434b79312022-12-21T20:47:45ZengAmerican Society for MicrobiologymBio2150-75112020-12-0111610.1128/mBio.02302-20Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated StressLindsey R. Burcham0Yoann Le Breton1Jana N. Radin2Brady L. Spencer3Liwen Deng4Aurélia Hiron5Monica R. Ransom6Jéssica da C. Mendonça7Ashton T. Belew8Najib M. El-Sayed9Kevin S. McIver10Thomas E. Kehl-Fie11Kelly S. Doran12Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USACell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USADepartment of Microbiology, University of Illinois at Urbana—Champaign, Urbana, Illinois, USADepartment of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USADepartment of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USAUniversité de Tours, INRAE, ISP, Tours, FranceDepartment of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USADepartment of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USACell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USACell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USACell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, USADepartment of Microbiology, University of Illinois at Urbana—Champaign, Urbana, Illinois, USADepartment of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, Colorado, USAABSTRACT Nutritional immunity is an elegant host mechanism used to starve invading pathogens of necessary nutrient metals. Calprotectin, a metal-binding protein, is produced abundantly by neutrophils and is found in high concentrations within inflammatory sites during infection. Group B Streptococcus (GBS) colonizes the gastrointestinal and female reproductive tracts and is commonly associated with severe invasive infections in newborns such as pneumonia, sepsis, and meningitis. Although GBS infections induce robust neutrophil recruitment and inflammation, the dynamics of GBS and calprotectin interactions remain unknown. Here, we demonstrate that disease and colonizing isolate strains exhibit susceptibility to metal starvation by calprotectin. We constructed a mariner transposon (Krmit) mutant library in GBS and identified 258 genes that contribute to surviving calprotectin stress. Nearly 20% of all underrepresented mutants following treatment with calprotectin are predicted metal transporters, including known zinc systems. As calprotectin binds zinc with picomolar affinity, we investigated the contribution of GBS zinc uptake to overcoming calprotectin-imposed starvation. Quantitative reverse transcriptase PCR (qRT-PCR) revealed a significant upregulation of genes encoding zinc-binding proteins, adcA, adcAII, and lmb, following calprotectin exposure, while growth in calprotectin revealed a significant defect for a global zinc acquisition mutant (ΔadcAΔadcAIIΔlmb) compared to growth of the GBS wild-type (WT) strain. Furthermore, mice challenged with the ΔadcAΔadcAIIΔlmb mutant exhibited decreased mortality and significantly reduced bacterial burden in the brain compared to mice infected with WT GBS; this difference was abrogated in calprotectin knockout mice. Collectively, these data suggest that GBS zinc transport machinery is important for combatting zinc chelation by calprotectin and establishing invasive disease. IMPORTANCE Group B Streptococcus (GBS) asymptomatically colonizes the female reproductive tract but is a common causative agent of meningitis. GBS meningitis is characterized by extensive infiltration of neutrophils carrying high concentrations of calprotectin, a metal chelator. To persist within inflammatory sites and cause invasive disease, GBS must circumvent host starvation attempts. Here, we identified global requirements for GBS survival during calprotectin challenge, including known and putative systems involved in metal ion transport. We characterized the role of zinc import in tolerating calprotectin stress in vitro and in a mouse model of infection. We observed that a global zinc uptake mutant was less virulent than the parental GBS strain and found calprotectin knockout mice to be equally susceptible to infection by wild-type (WT) and mutant strains. These findings suggest that calprotectin production at the site of infection results in a zinc-limited environment and reveals the importance of GBS metal homeostasis to invasive disease.https://journals.asm.org/doi/10.1128/mBio.02302-20GBScalprotectinmeningitisnutritional immunityzinc |
| spellingShingle | Lindsey R. Burcham Yoann Le Breton Jana N. Radin Brady L. Spencer Liwen Deng Aurélia Hiron Monica R. Ransom Jéssica da C. Mendonça Ashton T. Belew Najib M. El-Sayed Kevin S. McIver Thomas E. Kehl-Fie Kelly S. Doran Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress mBio GBS calprotectin meningitis nutritional immunity zinc |
| title | Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress |
| title_full | Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress |
| title_fullStr | Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress |
| title_full_unstemmed | Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress |
| title_short | Identification of Zinc-Dependent Mechanisms Used by Group B <italic toggle="yes">Streptococcus</italic> To Overcome Calprotectin-Mediated Stress |
| title_sort | identification of zinc dependent mechanisms used by group b italic toggle yes streptococcus italic to overcome calprotectin mediated stress |
| topic | GBS calprotectin meningitis nutritional immunity zinc |
| url | https://journals.asm.org/doi/10.1128/mBio.02302-20 |
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