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Chernykh A, Abrahams JL, Grant OC, Kambanis L, Sumer-Bayraktar Z, Ugonotti J, Kawahara R, Corcilius L, Payne RJ, Woods RJ, Thaysen-Andersen M. Position-specific N- and O-glycosylation of the reactive center loop impacts neutrophil elastase-mediated proteolysis of corticosteroid-binding globulin. J Biol Chem 2024; 300:105519. [PMID: 38042488 PMCID: PMC10784704 DOI: 10.1016/j.jbc.2023.105519] [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: 03/21/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
Corticosteroid-binding globulin (CBG) delivers anti-inflammatory cortisol to inflamed tissues through proteolysis of an exposed reactive center loop (RCL) by neutrophil elastase (NE). We previously demonstrated that RCL-localized Asn347-linked N-glycans impact NE proteolysis, but a comprehensive structure-function characterization of the RCL glycosylation is still required to better understand CBG glycobiology. Herein, we first performed RCL-centric glycoprofiling of serum-derived CBG to elucidate the Asn347-glycans and then used molecular dynamics simulations to study their impact on NE proteolysis. Importantly, we also identified O-glycosylation (di/sialyl T) across four RCL sites (Thr338/Thr342/Thr345/Ser350) of serum CBG close to the NE-targeted Val344-Thr345 cleavage site. A restricted N- and O-glycan co-occurrence pattern on the RCL involving exclusively Asn347 and Thr338 glycosylation was experimentally observed and supported in silico by modeling of a CBG-GalNAc-transferase (GalNAc-T) complex with various RCL glycans. GalNAc-T2 and GalNAc-T3 abundantly expressed by liver and gall bladder, respectively, showed in vitro a capacity to transfer GalNAc (Tn) to multiple RCL sites suggesting their involvement in RCL O-glycosylation. Recombinant CBG was then used to determine roles of RCL O-glycosylation through longitudinal NE-centric proteolysis experiments, which demonstrated that both sialoglycans (disialyl T) and asialoglycans (T) decorating Thr345 inhibit NE proteolysis. Synthetic RCL O-glycopeptides expanded on these findings by showing that Thr345-Tn and Thr342-Tn confer strong and moderate protection against NE cleavage, respectively. Molecular dynamics substantiated that short Thr345-linked O-glycans abrogate NE interactions. In conclusion, we report on biologically relevant CBG RCL glycosylation events, which improve our understanding of mechanisms governing cortisol delivery to inflamed tissues.
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Affiliation(s)
- Anastasia Chernykh
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Jodie L Abrahams
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia; Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Oliver C Grant
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Lucas Kambanis
- School of Chemistry, The University of Sydney, Sydney, New South Wales, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Zeynep Sumer-Bayraktar
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia; Glycometabolic Biochemistry Team, Cluster of Pioneering Research, RIKEN, Wako, Saitama, Japan
| | - Julian Ugonotti
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Rebeca Kawahara
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia; Institute for Glyco-core Research (iGCORE), Nagoya University, Nagoya, Japan
| | - Leo Corcilius
- School of Chemistry, The University of Sydney, Sydney, New South Wales, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Richard J Payne
- School of Chemistry, The University of Sydney, Sydney, New South Wales, Australia; Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Morten Thaysen-Andersen
- School of Natural Sciences, Macquarie University, Sydney, New South Wales, Australia; Institute for Glyco-core Research (iGCORE), Nagoya University, Nagoya, Japan.
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2
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Hastings CJ, Syed SS, Marques CNH. Subversion of the Complement System by Pseudomonas aeruginosa. J Bacteriol 2023; 205:e0001823. [PMID: 37436150 PMCID: PMC10464199 DOI: 10.1128/jb.00018-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen heavily implicated in chronic diseases. Immunocompromised patients that become infected with P. aeruginosa usually are afflicted with a lifelong chronic infection, leading to worsened patient outcomes. The complement system is an integral piece of the first line of defense against invading microorganisms. Gram-negative bacteria are thought to be generally susceptible to attack from complement; however, P. aeruginosa can be an exception, with certain strains being serum resistant. Various molecular mechanisms have been described that confer P. aeruginosa unique resistance to numerous aspects of the complement response. In this review, we summarize the current published literature regarding the interactions of P. aeruginosa and complement, as well as the mechanisms used by P. aeruginosa to exploit various complement deficiencies and the strategies used to disrupt or hijack normal complement activities.
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Affiliation(s)
- Cody James Hastings
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Shazrah Salim Syed
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
| | - Cláudia Nogueira Hora Marques
- Department of Biological Sciences, Binghamton University, Binghamton, New York, USA
- Binghamton Biofilm Research Center, Binghamton University, Binghamton, New York, USA
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3
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Uren Webster TM, Consuegra S, Garcia de Leaniz C. Early life stress causes persistent impacts on the microbiome of Atlantic salmon. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2021; 40:100888. [PMID: 34365156 PMCID: PMC8600188 DOI: 10.1016/j.cbd.2021.100888] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 07/27/2021] [Accepted: 07/27/2021] [Indexed: 01/06/2023]
Abstract
Farmed fish are commonly exposed to stress in intensive aquaculture systems, often leading to immune impairment and increased susceptibility to disease. As microbial communities associated with the gut and skin are vital to host health and disease resilience, disruption of microbiome integrity could contribute to the adverse consequences of stress exposure. Little is known about how stress affects the fish microbiome, especially during sensitive early life stages when initial colonisation and proliferation of host-associated microbial communities take place. Therefore, we compared the effects of two aquaculture-relevant early-life stressors on the gut and skin microbiome of Atlantic salmon fry (four months post hatching) using 16S rRNA amplicon sequencing. Acute cold stress applied during late embryogenesis had a pronounced, lasting effect on the structure of the skin microbiome, as well as a less consistent effect on the gut microbiome. Follow-up targeted qPCR assays suggested that this is likely due to disruption of the egg shell microbial communities at the initial stages of microbiome colonisation, with persistent effects on community structure. In contrast, chronic post hatching stress altered the structure of the gut microbiome, but not that of the skin. Both types of stress promoted similar Gammaproteobacteria ASVs, particularly within the genera Acinetobacter and Aeromonas, which include several important opportunistic fish pathogens. Our results demonstrate the sensitivity of the salmon microbiome to environmental stressors during early life, with potential associated health impacts on the host. We also identified common signatures of stress in the salmon microbiome, which may represent useful microbial stress biomarkers.
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Beyl HE, Jimeno B, Lynn SE, Breuner CW. Assay temperature affects corticosteroid-binding globulin and free corticosterone estimates across species. Gen Comp Endocrinol 2021; 310:113810. [PMID: 33964285 DOI: 10.1016/j.ygcen.2021.113810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 04/13/2021] [Accepted: 04/28/2021] [Indexed: 11/19/2022]
Abstract
Glucocorticoid hormones are often measured to assess how organisms physiologically respond to challenges in their environment. In plasma, glucocorticoids circulate in two forms: bound to corticosteroid-binding globulins (CBG) or unbound (free). Measuring CBG allows us to estimate the amount of free glucocorticoids present in a plasma sample. However, free glucocorticoid estimates are affected by the assay temperature used when measuring CBG, with colder temperatures maximizing specific binding but likely underestimating glucocorticoid's affinity for CBG. Here, we test how a biologically relevant incubation temperature (41 °C) changes the disassociation constant (Kd; used to estimate free glucocorticoid levels) when compared to the traditional 4 °C incubation temperature, across four commonly studied avian species. We then apply the new Kd's calculated at 41 °C to existing data sets to examine how the change in Kd affects free corticosterone estimates and data interpretation. Kd's were generally higher (lower affinity for CORT) at warmer incubation temperatures which resulted in higher levels of estimated free CORT in all four species but differed among subspecies. This increase in free CORT levels did not qualitatively change previously reported statistical relationships, but did affect variance and alpha (P) values. We suggest that future assays be run at biologically relevant temperatures for more accurate estimates of free CORT levels in vivo and to increase the chances of detecting biological patterns of free-CORT that may not be revealed with the classic methodology that tends to underestimate free CORT levels.
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Affiliation(s)
- Hannah E Beyl
- The Wildlife Biology Program, The University of Montana, 32 Campus Drive, HS 104, Missoula, MT 59801, United States.
| | - Blanca Jimeno
- Organismal Biology, Ecology, and Evolution, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT 59801, United States
| | - Sharon E Lynn
- Department of Biology, The College of Wooster, 931 College Mall, Wooster, OH 44619, United States
| | - Creagh W Breuner
- The Wildlife Biology Program, The University of Montana, 32 Campus Drive, HS 104, Missoula, MT 59801, United States; Organismal Biology, Ecology, and Evolution, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT 59801, United States
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5
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Pseudomonas aeruginosa elastase (LasB) as a therapeutic target. Drug Discov Today 2021; 26:2108-2123. [PMID: 33676022 DOI: 10.1016/j.drudis.2021.02.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/03/2021] [Accepted: 02/17/2021] [Indexed: 02/08/2023]
Abstract
Why is P. aeruginosa LasB elastase an attractive target for antivirulence therapy and what is the state-of-the art in LasB inhibitor design and development?
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6
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Breuner CW, Beyl HE, Malisch JL. Corticosteroid-binding globulins: Lessons from biomedical research. Mol Cell Endocrinol 2020; 514:110857. [PMID: 32437784 DOI: 10.1016/j.mce.2020.110857] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 04/17/2020] [Accepted: 04/29/2020] [Indexed: 11/19/2022]
Abstract
Glucocorticoids (GCs) circulate in the plasma bound to corticosteroid-binding globulin (CBG). Plasma CBG may limit access of glucocorticoids to tissues (acting as a sponge: the free hormone hypothesis), or may solely serve as a transport molecule, releasing GCs to tissues as the plasma moves through capillaries (the total hormone hypothesis). Both biomedical (focused on human health) and comparative (focused on ecological and evolutionary relevance) studies have worked to incorporate CBG in glucocorticoid physiology, and to understand whether free or total hormone is the biologically active plasma fraction. The biomedical field, however, has been well ahead of the comparative physiologists, and have produced results that can inform comparative research when considering the import of total vs. free plasma hormone. In fact, biomedical studies have made impressive strides regarding the function of CBG in tissues as well as plasma; we, however, focus solely on the plasma functions in this review as this is the primary area of disagreement amongst comparative physiologists. Here we present 5 sets of biomedical studies across genomics, pharmacology, cell culture, whole animal research, and human medicine that strongly support a role for CBG limiting hormone access to tissue. We also discuss three areas of concern across comparative researchers. In contrast to former publications, we are not suggesting that all comparative studies in glucocorticoid physiology must measure CBG, or that only free corticosterone levels are valid. However, we propose that comparative physiologists be aware of biomedical results as they investigate glucocorticoids and interpret how total hormone may or may not impact behavior and physiology of free-living vertebrates.
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Affiliation(s)
- Creagh W Breuner
- Organismal Biology, Ecology, and Evolution, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT, 59801, USA; The Wildlife Biology Program, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT, 59801, USA.
| | - Hannah E Beyl
- The Wildlife Biology Program, The University of Montana. 32 Campus Drive, HS 104, Missoula, MT, 59801, USA
| | - Jessica L Malisch
- Department of Biology, Schaeffer Hall 236, St. Mary's College of Maryland, St. Mary's City, MD, 20686, USA
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Uren Webster TM, Rodriguez-Barreto D, Consuegra S, Garcia de Leaniz C. Cortisol-Related Signatures of Stress in the Fish Microbiome. Front Microbiol 2020; 11:1621. [PMID: 32765459 PMCID: PMC7381252 DOI: 10.3389/fmicb.2020.01621] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 06/22/2020] [Indexed: 12/11/2022] Open
Abstract
Exposure to environmental stressors can compromise fish health and fitness. Little is known about how stress-induced microbiome disruption may contribute to these adverse health effects, including how cortisol influences fish microbial communities. We exposed juvenile Atlantic salmon to a mild confinement stressor for two weeks. We then measured cortisol in the plasma, skin-mucus, and feces, and characterized the skin and fecal microbiome. Fecal and skin cortisol concentrations increased in fish exposed to confinement stress, and were positively correlated with plasma cortisol. Elevated fecal cortisol was associated with pronounced changes in the diversity and structure of the fecal microbiome. In particular, we identified a marked decline in the lactic acid bacteria Carnobacterium sp. and an increase in the abundance of operational taxonomic units within the classes Clostridia and Gammaproteobacteria. In contrast, cortisol concentrations in skin-mucus were lower than in the feces, and were not related to any detectable changes in the skin microbiome. Our results demonstrate that stressor-induced cortisol production is associated with disruption of the gut microbiome, which may, in turn, contribute to the adverse effects of stress on fish health. They also highlight the value of using non-invasive fecal samples to monitor stress, including simultaneous determination of cortisol and stress-responsive bacteria.
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Affiliation(s)
- Tamsyn M. Uren Webster
- Centre for Sustainable Aquatic Research, College of Science, Swansea University, Swansea, United Kingdom
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8
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Hill LA, Sumer-Bayraktar Z, Lewis JG, Morava E, Thaysen-Andersen M, Hammond GL. N-Glycosylation influences human corticosteroid-binding globulin measurements. Endocr Connect 2019; 8:1136-1148. [PMID: 31307013 PMCID: PMC6686952 DOI: 10.1530/ec-19-0242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 07/15/2019] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Discrepancies in ELISA measurements of human corticosteroid-binding globulin (CBG) using detection monoclonal antibodies that recognize an epitope (9G12) within its reactive center loop (RCL), versus an epitope (12G2) in a different location, have suggested that CBG with a proteolytically cleaved RCL exists in blood samples. We have previously been unable to verify this biochemically, and sought to determine if N-glycosylation differences account for discrepancies in ELISA measurements of CBG. METHODS AND SUBJECTS Molecular biological, biochemical and glycopeptide analyses were used to examine how N-glycosylation at specific sites, including at N347 within the RCL, affect CBG ELISA or steroid-binding capacity assay (BCA) measurements. Plasma from patients with congenital disorders of glycosylation (CDG) was also examined in these assays as examples of N-glycosylation defects. RESULTS We demonstrate that an N-glycan at N347 within the CBG RCL limits the 9G12 antibody from recognizing its epitope, whereas the 12G2 antibody reactivity is unaffected, thereby contributing to discrepancies in ELISA measurements using these two antibodies. Qualitative differences in N-glycosylation at N238 also negatively affect the steroid-binding of CBG in the absence of an N-glycan at N347 caused by a T349A substitution. Desialylation increased both ELISA measurements relative to BCA values. Similarly, plasma CBG levels in both ELISAs were much higher than BCA values in several CDG patients. CONCLUSIONS Plasma CBG measurements are influenced by variations in N-glycosylation. This is important given the increasing number of CDG defects identified recently and because N-glycosylation abnormalities are common in patients with metabolic and liver diseases.
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Affiliation(s)
- Lesley A Hill
- Departments of Cellular and Physiological Sciences and Obstetrics and Gynaecology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Zeynep Sumer-Bayraktar
- School of Life and Environmental Science, Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia
| | - John G Lewis
- Canterbury Health Laboratories, Christchurch, New Zealand
| | - Eva Morava
- Mayo Clinic, Department of Clinical Genomics, CIM, Rochester, Minnesota, USA
| | | | - Geoffrey L Hammond
- Departments of Cellular and Physiological Sciences and Obstetrics and Gynaecology, The University of British Columbia, Vancouver, British Columbia, Canada
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9
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Hill LA, Vassiliadi DA, Dimopoulou I, Anderson AJ, Boyle LD, Kilgour AHM, Stimson RH, Machado Y, Overall CM, Walker BR, Lewis JG, Hammond GL. Neutrophil elastase-cleaved corticosteroid-binding globulin is absent in human plasma. J Endocrinol 2019; 240:27-39. [PMID: 30452386 PMCID: PMC6347282 DOI: 10.1530/joe-18-0479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 09/28/2018] [Indexed: 12/24/2022]
Abstract
Corticosteroid-binding globulin (CBG) transports glucocorticoids in blood and is a serine protease inhibitor family member. Human CBG has a reactive center loop (RCL) which, when cleaved by neutrophil elastase (NE), disrupts its steroid-binding activity. Measurements of CBG levels are typically based on steroid-binding capacity or immunoassays. Discrepancies in ELISAs using monoclonal antibodies that discriminate between intact vs RCL-cleaved CBG have been interpreted as evidence that CBG with a cleaved RCL and low affinity for cortisol exists in the circulation. We examined the biochemical properties of plasma CBG in samples with discordant ELISA measurements and sought to identify RCL-cleaved CBG in human blood samples. Plasma CBG-binding capacity and ELISA values were consistent in arterial and venous blood draining skeletal muscle, liver and brain, as well as from a tissue (adipose) expected to contain activated neutrophils in obese individuals. Moreover, RCL-cleaved CBG was undetectable in plasma from critically ill patients, irrespective of whether their ELISA measurements were concordant or discordant. We found no evidence of RCL-cleaved CBG in plasma using a heat-dependent polymerization assay, and CBG that resists immunoprecipitation with a monoclonal antibody designed to specifically recognize an intact RCL, bound steroids with a high affinity. In addition, mass spectrometry confirmed the absence of NE-cleaved CBG in plasma in which ELISA values were highly discordant. Human CBG with a NE-cleaved RCL and low affinity for steroids is absent in blood samples, and CBG ELISA discrepancies likely reflect structural differences that alter epitopes recognized by specific monoclonal antibodies.
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Affiliation(s)
- Lesley A Hill
- Departments of Cellular and Physiological Sciences and Obstetrics and Gynaecology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Dimitra A Vassiliadi
- Endocrine Unit, Second Department of Internal Medicine-Research Institute and Diabetes Center, Attiko University Hospital, Athens, Greece
| | - Ioanna Dimopoulou
- Endocrine Unit, Second Department of Internal Medicine-Research Institute and Diabetes Center, Attiko University Hospital, Athens, Greece
| | - Anna J Anderson
- BHF Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Luke D Boyle
- BHF Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Alixe H M Kilgour
- BHF Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Roland H Stimson
- BHF Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Yoan Machado
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher M Overall
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Brian R Walker
- BHF Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - John G Lewis
- Canterbury Health Laboratories, Christchurch, New Zealand
| | - Geoffrey L Hammond
- Departments of Cellular and Physiological Sciences and Obstetrics and Gynaecology, The University of British Columbia, Vancouver, British Columbia, Canada
- Correspondence should be addressed to G L Hammond:
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10
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Gudmand-Hoeyer J, Ottesen JT. Analysis and validation of a new extended method for estimating plasma free cortisol including neutrophil elastase and competition from other steroids. J Steroid Biochem Mol Biol 2018; 181:109-124. [PMID: 29678493 DOI: 10.1016/j.jsbmb.2018.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/15/2018] [Accepted: 04/13/2018] [Indexed: 12/11/2022]
Abstract
A non-linear mechanistic model for the distribution of cortisol in plasma on free and bound forms is proposed. The influence of progesterone, testosterone and neutrophil elastase on the cortisol distribution in the blood is investigated. The activity of neutrophil elastase is directly included in the model with the concentration of elastase and the kinetic constants describing the activity of elastase collected in one single input variable. The model is very sensitive towards this input variable and fits data excellently, when it is allowed to be subject specific. The analysis shows that steroids such as testosterone with low affinity for corticosteroid-binding globulin (CBG) do not significantly influence the concentration of free cortisol. Progesterone has a high affinity for CBG, but low plasma concentrations compared to cortisol. Contrary to expectations, progesterone is shown to impact the distribution of cortisol in plasma both under circumstances with high levels as seen in pregnancy and during the normal menstrual cycle of women. Comparing the predictions of our model with predictions made with the equilibrium models by Coolens et al. [1], Dorin et al. [2] and Nguyen et al. [3] shows that the models differ considerably not only in their predictions for free cortisol, but also for cortisol on bound forms; i.e. bound to albumin, intact CBG and elastase-cleaved CBG. Disregarding some of the smallest terms of the model equations a reduced version of the model in form of a fourth order polynomial equation is obtained. The reduced version of the model performs almost identically to the full version and serves as a new formula for calculating the plasma free cortisol concentration.
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Affiliation(s)
| | - Johnny T Ottesen
- Department of Science and Environment, Roskilde University, Denmark.
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11
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Tchoukaev A, Taytard J, Rousselet N, Rebeyrol C, Debray D, Blouquit-Laye S, Moisan MP, Foury A, Guillot L, Corvol H, Tabary O, Le Rouzic P. Opposite Expression of Hepatic and Pulmonary Corticosteroid-Binding Globulin in Cystic Fibrosis Patients. Front Pharmacol 2018; 9:545. [PMID: 29922157 PMCID: PMC5996105 DOI: 10.3389/fphar.2018.00545] [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: 03/23/2018] [Accepted: 05/08/2018] [Indexed: 01/02/2023] Open
Abstract
Cystic fibrosis (CF) is characterized by a chronic pulmonary inflammation. In CF, glucocorticoids (GC) are widely used, but their efficacy and benefit/risk ratio are still debated. In plasma, corticosteroid-binding globulin (CBG) binds 90% of GC and delivers them to the inflammatory site. The main goal of this work was to study CBG expression in CF patients in order to determine whether CBG could be used to optimize GC treatment. The expression of CBG was measured in liver samples from CF cirrhotic and non-CF cirrhotic patients by qPCR and Western blot and in lung samples from non-CF and CF patients by qPCR. CBG binding assays with 3H-cortisol and the measurement of the elastase/α1-antitrypsin complex were performed using the plasmas. CBG expression increased in the liver at the transcript and protein level but not in the plasma of CF patients. This is possibly due to an increase of plasmatic elastase. We demonstrated that pulmonary CBG was expressed in the bronchi and bronchioles and its expression decreased in the CF lungs, at both levels studied. Despite the opposite expression of hepatic and pulmonary CBG in CF patients, the concentration of CBG in the plasma was normal. Thus, CBG might be useful to deliver an optimized synthetic GC displaying high affinity for CBG to the main inflammatory site in the context of CF, e.g., the lung.
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Affiliation(s)
- Anastasia Tchoukaev
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France
| | - Jessica Taytard
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France.,Pediatric Respiratory Department, Trousseau Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Nathalie Rousselet
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France
| | - Carine Rebeyrol
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France
| | - Dominique Debray
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France.,Pediatric Hepatology Unit, Necker Enfants Malades Hospital, Paris, France
| | - Sabine Blouquit-Laye
- INSERM U1173, UFR des Sciences de la Santé Simone Veil, Université de Versailles Saint-Quentin-en-Yvelines, Versailles, France
| | - Marie-Pierre Moisan
- INRA, Laboratoire NutriNeurO, UMR 1286, Université de Bordeaux, Bordeaux, France
| | - Aline Foury
- INRA, Laboratoire NutriNeurO, UMR 1286, Université de Bordeaux, Bordeaux, France
| | - Loic Guillot
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France
| | - Harriet Corvol
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France.,Pediatric Respiratory Department, Trousseau Hospital, Assistance Publique - Hôpitaux de Paris, Paris, France
| | - Olivier Tabary
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France
| | - Philippe Le Rouzic
- INSERM, Centre de Recherche Saint-Antoine, Sorbonne Université, Paris, France
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12
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Simard M, Underhill C, Hammond GL. Functional implications of corticosteroid-binding globulin N-glycosylation. J Mol Endocrinol 2018; 60:71-84. [PMID: 29273683 PMCID: PMC5793714 DOI: 10.1530/jme-17-0234] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 12/22/2017] [Indexed: 12/21/2022]
Abstract
Corticosteroid-binding globulin (CBG) is a plasma carrier of glucocorticoids. Human and rat CBGs have six N-glycosylation sites. Glycosylation of human CBG influences its steroid-binding activity, and there are N-glycosylation sites in the reactive center loops (RCLs) of human and rat CBGs. Proteolysis of the RCL of human CBG causes a structural change that disrupts steroid binding. We now show that mutations of conserved N-glycosylation sites at N238 in human CBG and N230 in rat CBG disrupt steroid binding. Inhibiting glycosylation by tunicamycin also markedly reduced human and rat CBG steroid-binding activities. Deglycosylation of fully glycosylated human CBG or human CBG with only one N-glycan at N238 with Endo H-reduced steroid-binding affinity, while PNGase F-mediated deglycosylation does not, indicating that steroid binding is preserved by deamidation of N238 when its N-glycan is removed. When expressed in N-acetylglucosaminyltransferase-I-deficient Lec1 cells, human and rat CBGs, and a human CBG mutant with only one glycosylation site at N238, have higher (2-4 fold) steroid-binding affinities than when produced by sialylation-deficient Lec2 cells or glycosylation-competent CHO-S cells. Thus, the presence and composition of an N-glycan in this conserved position both appear to influence the steroid binding of CBG. We also demonstrate that neutrophil elastase cleaves the RCL of human CBG and reduces its steroid-binding capacity more efficiently than does chymotrypsin or the Pseudomonas aeruginosa protease LasB. Moreover, while glycosylation of N347 in the RCL limits these activities, N-glycans at other sites also appear to protect CBG from neutrophil elastase or chymotrypsin.
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Affiliation(s)
- Marc Simard
- Department of Cellular and Physiological SciencesThe University of British Columbia, Vancouver, British Columbia, Canada
| | - Caroline Underhill
- Department of Cellular and Physiological SciencesThe University of British Columbia, Vancouver, British Columbia, Canada
| | - Geoffrey L Hammond
- Department of Cellular and Physiological SciencesThe University of British Columbia, Vancouver, British Columbia, Canada
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Meyer EJ, Nenke MA, Lewis JG, Torpy DJ. Corticosteroid-binding globulin: acute and chronic inflammation. Expert Rev Endocrinol Metab 2017; 12:241-251. [PMID: 30058887 DOI: 10.1080/17446651.2017.1332991] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Corticosteroid-binding globulin (CBG) is the principal transport protein for cortisol binding 80% in a 1:1 ratio. Since its discovery in 1958, CBG's primary function has been considered to be cortisol transport within the circulation. More recent data indicate a cortisol tissue delivery function, particularly at inflammatory sites. CBG's structure as a non-inhibitory serine protease inhibitor allows allosteric structural change after reactive central loop (RCL) cleavage by neutrophil elastase (NE) and RCL insertion into CBG's protein core. Transition from the high to low affinity CBG form reduces cortisol-binding. Areas covered: In acute systemic inflammation, high affinity CBG (haCBG) is depleted proportionate to sepsis severity, with lowest levels seen in non-survivors. Conversely, in chronic inflammation, CBG cleavage is paradoxically reduced in proportion to disease severity, implying impaired targeted delivery of cortisol. CBG's structure allows thermosensitive release of bound cortisol, by reversible partial insertion of the RCL and loosening of CBG:cortisol binding. Recent studies indicate a significant frequency of function-altering single nucleotide polymorphisms of the SERPINA6 gene which may be important in population risk of inflammatory disease. Expert commentary: Further exploration of CBG in inflammatory disease may offer new avenues for treatment based on the model of optimal cortisol tissue delivery.
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Affiliation(s)
- Emily J Meyer
- a Endocrine and Metabolic Unit , Royal Adelaide Hospital , Adelaide , Australia
- b Discipline of Medicine , University of Adelaide , Adelaide , Australia
| | - Marni A Nenke
- a Endocrine and Metabolic Unit , Royal Adelaide Hospital , Adelaide , Australia
- b Discipline of Medicine , University of Adelaide , Adelaide , Australia
| | - John G Lewis
- c Steroid & Immunobiochemistry Laboratory , Canterbury Health Laboratories , Christchurch , New Zealand
| | - David J Torpy
- a Endocrine and Metabolic Unit , Royal Adelaide Hospital , Adelaide , Australia
- b Discipline of Medicine , University of Adelaide , Adelaide , Australia
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14
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Ngo Ndjom CG, Kantor LV, Jones HP. CRH Affects the Phenotypic Expression of Sepsis-Associated Virulence Factors by Streptococcus pneumoniae Serotype 1 In vitro. Front Cell Infect Microbiol 2017; 7:263. [PMID: 28690980 PMCID: PMC5479890 DOI: 10.3389/fcimb.2017.00263] [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: 01/16/2017] [Accepted: 06/02/2017] [Indexed: 12/20/2022] Open
Abstract
Sepsis is a life-threatening health condition caused by infectious pathogens of the respiratory tract, and accounts for 28–50% of annual deaths in the US alone. Current treatment regimen advocates the use of corticosteroids as adjunct treatment with antibiotics, for their broad inhibitory effect on the activity and production of pro-inflammatory mediators. However, despite their use, corticosteroids have not proven to be able to reverse the death incidence among septic patients. We have previously demonstrated the potential for neuroendocrine factors to directly influence Streptococcus pneumoniae virulence, which may in turn mediate disease outcome leading to sepsis and septic shock. The current study investigated the role of Corticotropin-releasing hormone (CRH) in mediating key markers of pneumococcal virulence as important phenotypic determinants of sepsis and septic shock risks. In vitro cultures of serotype 1 pneumococcal strain with CRH promoted growth rate, increased capsule thickness and penicillin resistance, as well as induced pneumolysin gene expression. These results thus provide significant insights of CRH–pathogen interactions useful in understanding the underlying mechanisms of neuroendocrine factor's role in the onset of community acquired pneumonias (CAP), sepsis and septic shock.
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Affiliation(s)
- Colette G Ngo Ndjom
- Department of Molecular and Medical Genetics, University of North Texas Health Science CenterFort Worth, TX, United States
| | - Lindsay V Kantor
- Graduate School of Biomedical Sciences, University of North Texas Health Science CenterFort Worth, TX, United States
| | - Harlan P Jones
- Department of Molecular and Medical Genetics, University of North Texas Health Science CenterFort Worth, TX, United States
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15
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Russell CD, Baillie JK. Treatable traits and therapeutic targets: Goals for systems biology in infectious disease. ACTA ACUST UNITED AC 2017; 2:140-146. [PMID: 32363252 PMCID: PMC7185428 DOI: 10.1016/j.coisb.2017.04.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Among the many medical applications of systems biology, we contend that infectious disease is one of the most important and tractable targets. We take the view that the complexity of the immune system is an inevitable consequence of its evolution, and this complexity has frustrated reductionist efforts to develop host-directed therapies for infection. However, since hosts vary widely in susceptibility and tolerance to infection, host-directed therapies are likely to be effective, by altering the biology of a susceptible host to induce a response more similar to a host who survives. Such therapies should exert minimal selection pressure on organisms, thus greatly decreasing the probability of pathogen resistance developing. A systems medicine approach to infection has the potential to provide new solutions to old problems: to identify host traits that are potentially amenable to therapeutic intervention, and the host immune factors that could be targeted by host-directed therapies. Furthermore, undiscovered sub-groups with different responses to treatment are almost certain to exist among patients presenting with life-threatening infection, since this population is markedly clinically heterogeneous. A major driving force behind high-throughput clinical phenotyping studies is the aspiration that these subgroups, hitherto opaque to observation, may be observed in the data generated by new technologies. Subgroups of patients are unlikely to be static – serial clinical and biological phenotyping may reveal different trajectories through the pathophysiology of disease, in which different therapeutic approaches are required. We suggest there are two major goals for systems biology in infection medicine: (1) to identify subgroups of patients that share treatable features; and, (2) to integrate high-throughput data from clinical and in vitro sources in order to predict tractable therapeutic targets with the potential to alter disease trajectories for individual patients. High throughput technologies can reveal clinical patterns in infection that were previously opaque. Host-targeted therapies have conceptual advantages but are difficult to develop. Key clinically-relevant objectives are identification of disease endotypes and treatable traits. Mechanistic understanding will reveal opportunities for drug design, repurposing and better targeting.
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Affiliation(s)
- Clark D Russell
- Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, UK
| | - J Kenneth Baillie
- Roslin Institute, University of Edinburgh, Midlothian EH25 9RG, UK
- Intensive Care Unit, Royal Infirmary of Edinburgh, Edinburgh EH16 4SA, UK
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16
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Nenke MA, Lewis JG, Rankin W, Shaw D, Torpy DJ. Corticosteroid-binding globulin cleavage may be pathogen-dependent in bloodstream infection. Clin Chim Acta 2016; 464:176-181. [PMID: 27887960 DOI: 10.1016/j.cca.2016.11.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/14/2016] [Accepted: 11/21/2016] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The process of enzymatic cleavage of high- to low-affinity corticosteroid-binding globulin (haCBG to laCBG) by neutrophil elastase leads to local tissue release of cortisol. Recently Pseudomonas aeruginosa was shown to instigate CBG cleavage with release of free cortisol in vitro. Hence, CBG cleavage with release of anti-inflammatory cortisol in infection may be pathogen-dependent. Our objective was to determine whether haCBG and laCBG levels are altered in infected patients compared with controls, and whether these alterations were particular to causative bacteria. DESIGN An observational, cross-sectional study at a public pathology institution and tertiary hospital in Adelaide, South Australia. METHODS 100 positive blood culture samples and 100 healthy control samples were analysed for serum total CBG, haCBG, laCBG, total and free cortisol, leukocyte and neutrophil count, C-reactive protein and Pitt severity score. RESULTS Patients with infection had lower serum total CBG, haCBG and laCBG, all P<0.0001, than healthy controls. This was true in patients with and without a systemic inflammatory response and in those with culture-positive and culture-negative infections. Pseudomonas aeruginosa infection was associated with the lowest total and laCBG levels of the pathogen groups despite having the lowest inflammatory markers. CONCLUSIONS There was evidence of CBG cleavage in early infection both in patients with and without systemic inflammation and regardless of culture status. Pseudomonas infection appeared to enhance cleavage. This observation, along with cleavage in severe neutropenia suggests mechanisms other than neutrophil elastase may be involved in CBG cleavage and local tissue cortisol release in infection.
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Affiliation(s)
- Marni A Nenke
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia; Discipline of Medicine, University of Adelaide, Adelaide, SA 5000, Australia.
| | - John G Lewis
- Steroid & Immunobiochemistry Laboratory, Canterbury Health Laboratories, Christchurch, New Zealand
| | - Wayne Rankin
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia; Discipline of Medicine, University of Adelaide, Adelaide, SA 5000, Australia; Chemical Pathology Directorate, SA Pathology, Adelaide, SA 5000, Australia
| | - David Shaw
- Infectious Diseases Clinical Service, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
| | - David J Torpy
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia; Discipline of Medicine, University of Adelaide, Adelaide, SA 5000, Australia
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17
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Abstract
The first mineralocorticoid receptor (MR) antagonist, spironolactone, was developed almost 60 years ago to treat primary aldosteronism and pathological edema. Its use waned in part because of its lack of selectivity. Subsequently, knowledge of the scope of MR function was expanded along with clinical evidence of the therapeutic importance of MR antagonists to prevent the ravages of inappropriate MR activation. Forty-two years elapsed between the first and MR-selective second generation of MR antagonists. Fifteen years later, despite serious shortcomings of the existing antagonists, a third-generation antagonist has yet to be marketed. Progress has been slowed by the lack of appreciation of the large variety of cell types that express the MR and its diverse cell-type-specific actions, and also its unique complex interaction actions at the molecular level. New MR antagonists should preferentially target the inflammatory and fibrotic effects of MR and perhaps its excitatory effects on sympathetic nervous system, but not the renal tubular epithelium or neurons of the cortex and hippocampus. This review briefly describes efforts to develop a third-generation MR antagonist and why fourth generation antagonists and selective agonists based on structural determinants of tissue and ligand-specific MR activation should be contemplated.
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18
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Nenke MA, Lewis JG, Rankin W, McWilliams L, Metcalf RG, Proudman SM, Torpy DJ. Reduced corticosteroid-binding globulin cleavage in active rheumatoid arthritis. Clin Endocrinol (Oxf) 2016; 85:369-77. [PMID: 27061835 DOI: 10.1111/cen.13081] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/23/2016] [Accepted: 04/05/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Corticosteroid-binding globulin (CBG), the cortisol transport protein, is cleaved from high-affinity (haCBG) to low-affinity (laCBG) CBG at sites of inflammation releasing bioavailable, anti-inflammatory cortisol. Rheumatoid arthritis (RA) is a glucocorticoid-responsive disorder, with paradoxically normal cortisol levels despite elevated inflammatory mediators. Our objective was to determine whether CBG cleavage relates to RA disease activity. We hypothesized that impaired CBG cleavage may limit delivery of free cortisol to inflamed joints in RA. DESIGN Prospective, cross-sectional observational study. SETTING AND PARTICIPANTS Fifty-three patients with RA recruited from a Rheumatology outpatient clinic at a tertiary referral centre in Adelaide, Australia, and 73 healthy controls. MEASUREMENTS Total CBG, haCBG and laCBG, total, free and salivary cortisol, inflammatory markers including interleukin-6 soluble receptor (IL-6sR) and macrophage migration inhibitory factor and clinical measures of disease activity. RESULTS Among patients with RA, a wide range of disease activity scores was observed (DAS28: range 1·2-6·4). laCBG was lower in patients with RA (mean ± SEM); 153 ± 9, compared with healthy controls; 191 ± 8 nmol/l, P = 0·003. Levels of total and haCBG were higher in patients with more severe RA disease activity. Free and total cortisol, free cortisol:IL-6sR ratio and total cortisol:IL-6sR ratio correlated negatively with disease activity. CONCLUSIONS These results suggest that patients with RA have reduced CBG cleavage compared to healthy controls and that cleavage is reduced further with higher RA disease activity. Hence, impaired CBG-mediated delivery of endogenous cortisol may perpetuate chronic inflammation in RA.
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Affiliation(s)
- Marni A Nenke
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
- Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
| | - John G Lewis
- Steroid & Immunobiochemistry Laboratory, Canterbury Health Laboratories, Christchurch, New Zealand
| | - Wayne Rankin
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
- Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
- Chemical Pathology Directorate, SA Pathology, Adelaide, SA, Australia
| | - Leah McWilliams
- Rheumatology Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Robert G Metcalf
- Rheumatology Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - Susanna M Proudman
- Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
- Rheumatology Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
| | - David J Torpy
- Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide, SA, Australia
- Discipline of Medicine, University of Adelaide, Adelaide, SA, Australia
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19
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Sumer-Bayraktar Z, Grant OC, Venkatakrishnan V, Woods RJ, Packer NH, Thaysen-Andersen M. Asn347 Glycosylation of Corticosteroid-binding Globulin Fine-tunes the Host Immune Response by Modulating Proteolysis by Pseudomonas aeruginosa and Neutrophil Elastase. J Biol Chem 2016; 291:17727-42. [PMID: 27339896 PMCID: PMC5016167 DOI: 10.1074/jbc.m116.735258] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/10/2016] [Indexed: 12/23/2022] Open
Abstract
Corticosteroid-binding globulin (CBG) delivers anti-inflammatory cortisol to inflamed tissues upon elastase-based proteolysis of the exposed reactive center loop (RCL). However, the molecular mechanisms that regulate the RCL proteolysis by co-existing host and bacterial elastases in inflamed/infected tissues remain unknown. We document that RCL-localized Asn(347) glycosylation fine-tunes the RCL cleavage rate by human neutrophil elastase (NE) and Pseudomonas aeruginosa elastase (PAE) by different mechanisms. NE- and PAE-generated fragments of native and exoglycosidase-treated blood-derived CBG of healthy individuals were monitored by gel electrophoresis and LC-MS/MS to determine the cleavage site(s) and Asn(347) glycosylation as a function of digestion time. The site-specific (Val(344)-Thr(345)) and rapid (seconds to minutes) NE-based RCL proteolysis was significantly antagonized by several volume-enhancing Asn(347) glycan features (i.e. occupancy, triantennary GlcNAc branching, and α1,6-fucosylation) and augmented by Asn(347) NeuAc-type sialylation (all p < 0.05). In contrast, the inefficient (minutes to hours) PAE-based RCL cleavage, which occurred equally well at Thr(345)-Leu(346) and Asn(347)-Leu(348), was abolished by the presence of Asn(347) glycosylation but was enhanced by sialoglycans on neighboring CBG N-sites. Molecular dynamics simulations of various Asn(347) glycoforms of uncleaved CBG indicated that multiple Asn(347) glycan features are modulating the RCL digestion efficiencies by NE/PAE. Finally, high concentrations of cortisol showed weak bacteriostatic effects toward virulent P. aeruginosa, which may explain the low RCL potency of the abundantly secreted PAE during host infection. In conclusion, site-specific CBG N-glycosylation regulates the bioavailability of cortisol in inflamed environments by fine-tuning the RCL proteolysis by endogenous and exogenous elastases. This study offers new molecular insight into host- and pathogen-based manipulation of the human immune system.
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Affiliation(s)
- Zeynep Sumer-Bayraktar
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia and
| | - Oliver C Grant
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Vignesh Venkatakrishnan
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia and
| | - Robert J Woods
- the Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602
| | - Nicolle H Packer
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia and
| | - Morten Thaysen-Andersen
- From the Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia and
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20
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Hill LA, Bodnar TS, Weinberg J, Hammond GL. Corticosteroid-binding globulin is a biomarker of inflammation onset and severity in female rats. J Endocrinol 2016; 230:215-25. [PMID: 27418032 PMCID: PMC5338597 DOI: 10.1530/joe-16-0047] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 06/03/2016] [Indexed: 12/25/2022]
Abstract
Plasma corticosteroid-binding globulin (CBG) plays a critical role in regulating glucocorticoid bioavailability and is an acute phase 'negative' protein during inflammation. In an adjuvant-induced arthritis model, plasma CBG levels decrease in rats that develop severe inflammation, and we have now determined when and how these reductions in CBG occur. After administering complete Freund's adjuvant or saline intra-dermally at the tail base, blood samples were taken periodically for 16days. In adjuvant-treated rats, decreases in plasma CBG levels matched the severity of inflammation, and decreases were observed 4days before any clinical signs of inflammation. Decreases in CBG levels coincided with an ~5kDa reduction in its apparent size, consistent with proteolytic cleavage, and cleaved CBG lacked steroid-binding activity. At the termination of the experimental period, hepatic Cbg mRNA levels were decreased in rats with severe inflammation. While plasma TNF-α increased in all adjuvant-treated rats, increases in Il-4, IL-6, IL-10, IL-13 and IFN-γ were only observed in rats with cleaved CBG. Rats with cleaved CBG also exhibited increased spleen weights, and strong negative correlations were observed among CBG, IL-6 and spleen weights, respectively. However, there were no differences in hepatic Cbg mRNA levels in relation to the apparent proteolysis of CBG, suggesting that CBG cleavage occurs before changes in hepatic Cbg expression. Our results indicate that the levels and integrity of plasma CBG are biomarkers of the onset and severity of inflammation. Dynamic changes in the levels and function of CBG likely modulate the tissue availability of corticosterone during inflammation.
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Affiliation(s)
- Lesley A Hill
- Department of Cellular and Physiological SciencesUniversity of British Columbia, Vancouver, British Columbia, Canada Department of Obstetrics and GynaecologyUniversity of British Columbia, Vancouver, British Columbia, Canada
| | - Tamara S Bodnar
- Department of Cellular and Physiological SciencesUniversity of British Columbia, Vancouver, British Columbia, Canada
| | - Joanne Weinberg
- Department of Cellular and Physiological SciencesUniversity of British Columbia, Vancouver, British Columbia, Canada
| | - Geoffrey L Hammond
- Department of Cellular and Physiological SciencesUniversity of British Columbia, Vancouver, British Columbia, Canada Department of Obstetrics and GynaecologyUniversity of British Columbia, Vancouver, British Columbia, Canada
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21
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Hammond GL. Plasma steroid-binding proteins: primary gatekeepers of steroid hormone action. J Endocrinol 2016; 230:R13-25. [PMID: 27113851 PMCID: PMC5064763 DOI: 10.1530/joe-16-0070] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 04/22/2016] [Indexed: 12/11/2022]
Abstract
Biologically active steroids are transported in the blood by albumin, sex hormone-binding globulin (SHBG), and corticosteroid-binding globulin (CBG). These plasma proteins also regulate the non-protein-bound or 'free' fractions of circulating steroid hormones that are considered to be biologically active; as such, they can be viewed as the 'primary gatekeepers of steroid action'. Albumin binds steroids with limited specificity and low affinity, but its high concentration in blood buffers major fluctuations in steroid concentrations and their free fractions. By contrast, SHBG and CBG play much more dynamic roles in controlling steroid access to target tissues and cells. They bind steroids with high (~nM) affinity and specificity, with SHBG binding androgens and estrogens and CBG binding glucocorticoids and progesterone. Both are glycoproteins that are structurally unrelated, and they function in different ways that extend beyond their transportation or buffering functions in the blood. Plasma SHBG and CBG production by the liver varies during development and different physiological or pathophysiological conditions, and abnormalities in the plasma levels of SHBG and CBG or their abilities to bind steroids are associated with a variety of pathologies. Understanding how the unique structures of SHBG and CBG determine their specialized functions, how changes in their plasma levels are controlled, and how they function outside the blood circulation provides insight into how they control the freedom of steroids to act in health and disease.
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Affiliation(s)
- Geoffrey L Hammond
- Departments of Cellular & Physiological Sciences and Obstetrics & GynaecologyUniversity of British Columbia, Vancouver, British Columbia, Canada
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22
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Vashchenko G, Das S, Moon KM, Rogalski JC, Taves MD, Soma KK, Van Petegem F, Foster LJ, Hammond GL. Identification of Avian Corticosteroid-binding Globulin (SerpinA6) Reveals the Molecular Basis of Evolutionary Adaptations in SerpinA6 Structure and Function as a Steroid-binding Protein. J Biol Chem 2016; 291:11300-12. [PMID: 27026706 DOI: 10.1074/jbc.m116.714378] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Indexed: 11/06/2022] Open
Abstract
Corticosteroid-binding globulin (CBG) was isolated from chicken serum and identified by mass spectrometry and genomic analysis. This revealed that the organization and synteny of avian and mammalian SerpinA6 genes are conserved. Recombinant zebra finch CBG steroid-binding properties reflect those of the natural protein in plasma and confirm its identity. Zebra finch and rat CBG crystal structures in complex with cortisol resemble each other, but their primary structures share only ∼40% identity, and their steroid-binding site topographies differ in several unexpected ways. Remarkably, a tryptophan that anchors ligands in mammalian CBG steroid-binding sites is replaced by an asparagine. Phylogenetic comparisons show that reptilian CBG orthologs share this unexpected property. Glycosylation of this asparagine in zebra finch CBG does not influence its steroid-binding affinity, but we present evidence that it may participate in protein folding and steroid-binding site formation. Substitutions of amino acids within zebra finch CBG that are conserved only in birds reveal how they contribute to their distinct steroid-binding properties, including their high (nanomolar) affinities for glucocorticoids, progesterone, and androgens. As in mammals, a protease secreted by Pseudomonas aeruginosa cleaves CBG in zebra finch plasma within its reactive center loop and disrupts steroid binding, suggesting an evolutionarily conserved property of CBGs. Measurements of CBG mRNA in zebra finch tissues indicate that liver is the main site of plasma CBG production, and anti-zebra finch CBG antibodies cross-react with CBGs in other birds, extending opportunities to study how CBG regulates the actions of glucocorticoids and sex steroids in these species.
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Affiliation(s)
| | - Samir Das
- Biochemistry and Molecular Biology, and
| | | | | | - Matthew D Taves
- Psychology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Kiran K Soma
- Psychology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Structural characterization of zinc-bound Zmp1, a zinc-dependent metalloprotease secreted by Clostridium difficile. J Biol Inorg Chem 2015; 21:185-96. [DOI: 10.1007/s00775-015-1319-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 11/28/2015] [Indexed: 10/22/2022]
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24
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Corticosteroid-binding globulin cleavage is paradoxically reduced in alpha-1 antitrypsin deficiency: Implications for cortisol homeostasis. Clin Chim Acta 2015; 452:27-31. [PMID: 26522656 DOI: 10.1016/j.cca.2015.10.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 10/27/2015] [Accepted: 10/27/2015] [Indexed: 12/30/2022]
Abstract
High-affinity corticosteroid-binding globulin (haCBG) is cleaved by neutrophil elastase (NE) resulting in permanent transition to the low cortisol-binding affinity form (laCBG), thereby increasing cortisol availability at inflammatory sites. Alpha-1 antitrypsin (AAT) is the major inhibitor of NE. AAT deficiency (AATD) predisposes patients to early-onset emphysema due to increased proteolytic destruction from the inherent proteinase-antiproteinase imbalance. We hypothesized that AATD may result in increased CBG cleavage in vivo. We collected demographic data and blood samples from 10 patients with AATD and 28 healthy controls measuring total CBG and haCBG levels by parallel in-house ELISAs, as well as AAT, total and free cortisol levels. haCBG was higher (median [range]); 329 [210-551] vs. 250 [175-365] nmol/L; P<0.005, and laCBG lower; 174 [68-229] vs. 220 [119-348] nmol/L; P=0.016 in the AATD group, compared with controls. The ratio of haCBG:total CBG was also higher in AATD; 72 [53-83] vs. 54 [41-72] %; P=0.0001). There was a negative correlation between haCBG:total CBG and AAT levels (P<0.05, R=-0.64). Paradoxically, proteolytic cleavage of CBG was reduced in AATD, despite the recognized increase in NE activity. This implies that NE activity is not the mechanism for systemic CBG cleavage in basal, low inflammatory conditions. Relatively low levels of laCBG may have implications for cortisol action in AATD.
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25
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Richter ME, Neugebauer S, Engelmann F, Hagel S, Ludewig K, La Rosée P, Sayer HG, Hochhaus A, von Lilienfeld-Toal M, Bretschneider T, Pausch C, Engel C, Brunkhorst FM, Kiehntopf M. Biomarker candidates for the detection of an infectious etiology of febrile neutropenia. Infection 2015; 44:175-86. [PMID: 26275448 DOI: 10.1007/s15010-015-0830-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 07/31/2015] [Indexed: 01/01/2023]
Abstract
PURPOSE Infections and subsequent septicemia are major complications in neutropenic patients with hematological malignancies. Here, we identify biomarker candidates for the early detection of an infectious origin, and monitoring of febrile neutropenia (FN). METHODS Proteome, metabolome, and conventional biomarkers from 20 patients with febrile neutropenia without proven infection (FNPI) were compared to 28 patients with proven infection, including 17 patients with bacteremia. RESULTS Three peptides (mass to charge ratio 1017.4-1057.3; p-values 0.011-0.024), six proteins (mass to charge ratio 6881-17,215; p-values 0.002-0.004), and six phosphatidylcholines (p-values 0.007-0.037) were identified that differed in FNPI patients compared to patients with infection or bacteremia. Seven of these marker candidates discriminated FNPI from infection at fever onset with higher sensitivity and specificity (ROC-AUC 0.688-0.824) than conventional biomarkers i.e., procalcitonin, C-reactive protein, or interleukin-6 (ROC-AUC 0.535-0.672). In a post hoc analysis, monitoring the time course of four lysophosphatidylcholines, threonine, and tryptophan allowed for discrimination of patients with or without resolution of FN (ROC-AUC 0.648-0.919) with higher accuracy compared to conventional markers (ROC-AUC 0.514-0.871). CONCLUSIONS Twenty-one promising biomarker candidates for the early detection of an infectious origin or for monitoring the course of FN were found which might overcome known shortcomings of conventional markers.
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Affiliation(s)
- Martin E Richter
- Institut für Klinische Chemie und Laboratoriumsdiagnostik, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Sophie Neugebauer
- Institut für Klinische Chemie und Laboratoriumsdiagnostik, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Falco Engelmann
- Institut für Klinische Chemie und Laboratoriumsdiagnostik, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Stefan Hagel
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Zentrum für Infektionsmedizin und Krankenhaushygiene, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Klinik für Innere Medizin IV (Gastroenterologie, Hepatologie, Infektiologie), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Katrin Ludewig
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Paul La Rosée
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Klinik für Innere Medizin II, Abt. Hämatologie und Intern. Onkologie, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Herbert G Sayer
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Klinik für Innere Medizin II, Abt. Hämatologie und Intern. Onkologie, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,4. Medizinische Klinik (Hämatologie und internistische Onkologie, Hämostaseologie), HELIOS Klinikum Erfurt, Nordhäuser Straße 74, 99089, Erfurt, Germany
| | - Andreas Hochhaus
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Klinik für Innere Medizin II, Abt. Hämatologie und Intern. Onkologie, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Marie von Lilienfeld-Toal
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Klinik für Innere Medizin II, Abt. Hämatologie und Intern. Onkologie, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany
| | - Tom Bretschneider
- Leibniz Institut für Naturstoff-Forschung und Infektionsbiologie, Hans-Knöll-Institut, Adolf-Reichwein-Straße 23, 07745, Jena, Germany
| | - Christine Pausch
- Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.,Institut für Medizinische Informatik, Statistik und Epidemiologie, Universität Leipzig, Härtelstraße 16-18, 04107, Leipzig, Germany
| | - Christoph Engel
- Institut für Medizinische Informatik, Statistik und Epidemiologie, Universität Leipzig, Härtelstraße 16-18, 04107, Leipzig, Germany
| | - Frank M Brunkhorst
- Zentrum für Klinische Studien, Universitätsklinikum Jena, Salvador-Allende-Platz 27, 07747, Jena, Germany
| | - Michael Kiehntopf
- Institut für Klinische Chemie und Laboratoriumsdiagnostik, Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany. .,Integriertes Forschungs- und Behandlungszentrum Sepsis und Sepsisfolgen (CSCC), Universitätsklinikum Jena, Erlanger Allee 101, 07747, Jena, Germany.
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Lewis JG, Saunders K, Dyer A, Elder PA. The half-lives of intact and elastase cleaved human corticosteroid-binding globulin (CBG) are identical in the rabbit. J Steroid Biochem Mol Biol 2015; 149:53-7. [PMID: 25636722 DOI: 10.1016/j.jsbmb.2015.01.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/21/2015] [Accepted: 01/23/2015] [Indexed: 10/24/2022]
Abstract
Corticosteroid-binding globulin (CBG) is a non-inhibitory member of the serpin superfamily of serine protease inhibitors and carries the majority of cortisol in circulation. It can be cleaved by neutrophil elastase at its exposed reactive centre loop which decreases its affinity for cortisol allowing the release of most of the cortisol at sites of inflammation. Intact and elastase cleaved CBG can be distinguished from each other and can coexist in circulation but with unknown half-lives. Here we treated a portion of purified human CBG with elastase, terminated the digestion and then combined this portion with intact human CBG and measured their respective half-lives in rabbits by ELISA. This investigation shows for the first time that the half-lives of intact and elastase cleaved CBG are identical (∼10h). This is an important finding as it implies that in conditions such as sepsis and septic shock where levels of intact CBG are low and the proportion of cleaved CBG is high that this is likely sustained which may affect the CBG mediated targeted delivery of cortisol to sites of inflammation. Furthermore the residual binding of cortisol to cleaved CBG may alter the overall buffering capacity of CBG for cortisol resetting the baseline concentration of free cortisol.
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Affiliation(s)
- John G Lewis
- Steroid & Immunobiochemistry Laboratory, Canterbury Health Laboratories, P.O.Box 151, Christchurch 8001, New Zealand.
| | - Katie Saunders
- Christchurch School of Medicine, University of Otago, 2 Riccarton Ave, Christchurch, New Zealand
| | - Arron Dyer
- Christchurch School of Medicine, University of Otago, 2 Riccarton Ave, Christchurch, New Zealand
| | - Peter A Elder
- Steroid & Immunobiochemistry Laboratory, Canterbury Health Laboratories, P.O.Box 151, Christchurch 8001, New Zealand
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27
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Ndjom CGN, Jones HP. CRH promotes S. pneumoniae growth in vitro and increases lung carriage in mice. Front Microbiol 2015; 6:279. [PMID: 25904910 PMCID: PMC4389549 DOI: 10.3389/fmicb.2015.00279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 03/19/2015] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae (S. pneumoniae), a commensal across the nasal passages, is responsible for the majority of infectious pneumonia cases worldwide. Previous studies have shown that hormonal factors may be influential in regulating S. pneumoniae’s transition from a non-pathogen to a pathogenic state. The current study investigated the effects of corticotropin-releasing hormone (CRH), a peptide hormone involved in stress, on the pathogenicity of S. pneumoniae. Mice were infected with CRH-treated S. pneumoniae via intranasal route, showing an increase in pulmonary bacterial burden. We also quantified S. pneumoniae’s response to CRH through limited serial dilutions and growth curve analysis. We demonstrated that CRH promotes S. pneumoniae titer-dependent proliferation, as well as accelerates log-phase growth. Results also showed an increase in pneumococcal-associated virulence protein A virulence gene expression in response to CRH. These results demonstrate a role for CRH in S. pneumoniae pathogenicity, thus implicating CRH in mediating the transition of S. pneumoniae into a pathogenic state.
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Affiliation(s)
- Colette G Ngo Ndjom
- Department of Molecular and Medical Genetics, University of North Texas Health Science Center, Fort Worth, TX USA ; Center for Biotechnology Education, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD USA
| | - Harlan P Jones
- Department of Molecular and Medical Genetics, University of North Texas Health Science Center, Fort Worth, TX USA
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