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Pokorzynski ND, Thompson CC, Carabeo RA. Ironing Out the Unconventional Mechanisms of Iron Acquisition and Gene Regulation in Chlamydia. Front Cell Infect Microbiol 2017; 7:394. [PMID: 28951853 PMCID: PMC5599777 DOI: 10.3389/fcimb.2017.00394] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 08/23/2017] [Indexed: 01/19/2023] Open
Abstract
The obligate intracellular pathogen Chlamydia trachomatis, along with its close species relatives, is known to be strictly dependent upon the availability of iron. Deprivation of iron in vitro induces an aberrant morphological phenotype termed "persistence." This persistent phenotype develops in response to various immunological and nutritional insults and may contribute to the development of sub-acute Chlamydia-associated chronic diseases in susceptible populations. Given the importance of iron to Chlamydia, relatively little is understood about its acquisition and its role in gene regulation in comparison to other iron-dependent bacteria. Analysis of the genome sequences of a variety of chlamydial species hinted at the involvement of unconventional mechanisms, being that Chlamydia lack many conventional systems of iron homeostasis that are highly conserved in other bacteria. Herein we detail past and current research regarding chlamydial iron biology in an attempt to provide context to the rapid progress of the field in recent years. We aim to highlight recent discoveries and innovations that illuminate the strategies involved in chlamydial iron homeostasis, including the vesicular mode of acquiring iron from the intracellular environment, and the identification of a putative iron-dependent transcriptional regulator that is synthesized as a fusion with a ABC-type transporter subunit. These recent findings, along with the noted absence of iron-related homologs, indicate that Chlamydia have evolved atypical approaches to the problem of iron homeostasis, reinvigorating research into the iron biology of this pathogen.
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Affiliation(s)
- Nick D Pokorzynski
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State UniversityPullman, WA, United States
| | - Christopher C Thompson
- Jefferiss Trust Laboratories, Faculty of Medicine, Imperial College London, St. Mary's HospitalLondon, United Kingdom
| | - Rey A Carabeo
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State UniversityPullman, WA, United States
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Iron Homeostasis in Tissues Is Affected during Persistent Chlamydia pneumoniae Infection in Mice. BIOMED RESEARCH INTERNATIONAL 2017; 2017:3642301. [PMID: 28691023 PMCID: PMC5485268 DOI: 10.1155/2017/3642301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 05/09/2017] [Indexed: 11/18/2022]
Abstract
Chlamydia pneumoniae (C. pneumoniae) may be a mediator in the pathogenesis of atherosclerosis. For its growth C. pneumoniae depends on iron (Fe), but how Fe changes in tissues during persistent infection or affects bacterial replication in tissues is unknown. C. pneumoniae-infected C57BL/6J mice were sacrificed on days 4, 8, 20, and 40. Mice had bacteria in the lungs and liver on all days. Inflammatory markers, chemokine Cxcl2 and interferon-gamma, were not affected in the liver on day 40. The copper (Cu)/zinc (Zn) ratio in serum, another marker of infection/inflammation, increased on day 4 and tended to increase again on day 40. The Fe markers, transferrin receptor (TfR), Hepcidin (Hamp1), and ferroportin 1 (Fpn1), increased in the liver on day 4 and then normalized except for TfR that tended to decrease. TfR responses were similar to Fe in serum that increased on day 4 but tended to decrease thereafter. In the liver, Fe was increased on day 4 and also on day 40. The reappearing increases in Cu/Zn on day 40 concomitant with the increase in liver Fe on day 40, even though TfR tended to decrease, and the fact that viable C. pneumoniae was present in the lungs and liver may indicate the early phase of activation of recurrent infection.
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Edvinsson M, Ilbäck NG, Frisk P, Thelin S, Nyström-Rosander C. Trace Element Changes in Thoracic Aortic Dissection. Biol Trace Elem Res 2016; 169:159-63. [PMID: 26152852 DOI: 10.1007/s12011-015-0432-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 06/29/2015] [Indexed: 01/10/2023]
Abstract
Thoracic aortic dissection is a life-threatening condition with an incompletely understood pathogenesis. Trace elements are essential for the functioning of different processes in the body, including the immune system and associated responses to infection/inflammation. Because inflammation may be part of the pathogenesis of thoracic aortic dissection, we investigated whether trace element changes associated with inflammation occur in serum and tissue samples during the disease. The study included 21 patients undergoing surgery for thoracic aortic dissection, 10 forensic autopsy specimens for tissue controls and 23 healthy blood donors for serum controls. Levels of magnesium (Mg), calcium (Ca), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd) and mercury (Hg) were measured in the aortic tissue and serum by inductively coupled plasma-mass spectrometry (ICP-MS). In the serum, Ca, V, Cu and Zn decreased, whereas Fe increased. In the tissue, Cu and Zn decreased and Fe tended to increase. The Cu/Zn ratio in the serum, a marker of infection/inflammation, did not change in the patients. Concerning trace element changes in the serum and tissue, our data do not support the hypothesis that inflammation is involved in the pathogenesis of thoracic aortic dissection.
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Affiliation(s)
- Marie Edvinsson
- Department of Medical Sciences, Infectious Diseases, Uppsala University, University Hospital, S-751 85, Uppsala, Sweden.
| | - Nils-Gunnar Ilbäck
- Department of Medical Sciences, Infectious Diseases, Uppsala University, University Hospital, S-751 85, Uppsala, Sweden
- Risk Benefit Assessment Department, National Food Agency, Box 622, 751 26, Uppsala, Sweden
| | - Peter Frisk
- Research in Metal Biology, Rudbeck Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Stefan Thelin
- Department of Surgical Sciences, Thoracic Surgery, Uppsala University, 751 85, Uppsala, Sweden
| | - Christina Nyström-Rosander
- Department of Medical Sciences, Infectious Diseases, Uppsala University, University Hospital, S-751 85, Uppsala, Sweden
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Weinberg ED. Iron loading in humans: A risk factor for enhanced morbidity and mortality. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/13590840601167685] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Abstract
The numerous acute and chronic diseases associated with excessive/misplaced iron are categorized in this review in the following sections: 1) iron, by itself, can initiate the disease; 2) iron can be a cofactor in promoting the disease; 3) iron deposits are observed in disease-associated tissue sites; 4) body iron loading is associated with above normal incidence of the disease; and 5) maternal antibodies can impair fetal iron metabolism. Also discussed is the anomalous condition in which persons whose macrophages are low in iron are resistant to microbial pathogens that require iron loaded macrophages for in vivo growth. Thus, hemochromatotic mutations have apparently had survival value during outbreaks of tuberculosis, plague and typhoid fever.
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Affiliation(s)
- Eugene D Weinberg
- Department of Biology and Program in Medical Sciences, Indiana University, Bloomington, Indiana 47405, USA.
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Mäurer AP, Mehlitz A, Mollenkopf HJ, Meyer TF. Gene expression profiles of Chlamydophila pneumoniae during the developmental cycle and iron depletion-mediated persistence. PLoS Pathog 2007; 3:e83. [PMID: 17590080 PMCID: PMC1894823 DOI: 10.1371/journal.ppat.0030083] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Accepted: 04/23/2007] [Indexed: 12/01/2022] Open
Abstract
The obligate intracellular, gram-negative bacterium Chlamydophila pneumoniae (Cpn) has impact as a human pathogen. Little is known about changes in the Cpn transcriptome during its biphasic developmental cycle (the acute infection) and persistence. The latter stage has been linked to chronic diseases. To analyze Cpn CWL029 gene expression, we designed a pathogen-specific oligo microarray and optimized the extraction method for pathogen RNA. Throughout the acute infection, ratio expression profiles for each gene were generated using 48 h post infection as a reference. Based on these profiles, significantly expressed genes were separated into 12 expression clusters using self-organizing map clustering and manual sorting into the “early”, “mid”, “late”, and “tardy” cluster classes. The latter two were differentiated because the “tardy” class showed steadily increasing expression at the end of the cycle. The transcriptome of the Cpn elementary body (EB) and published EB proteomics data were compared to the cluster profile of the acute infection. We found an intriguing association between “late” genes and genes coding for EB proteins, whereas “tardy” genes were mainly associated with genes coding for EB mRNA. It has been published that iron depletion leads to Cpn persistence. We compared the gene expression profiles during iron depletion–mediated persistence with the expression clusters of the acute infection. This led to the finding that establishment of iron depletion–mediated persistence is more likely a mid-cycle arrest in development rather than a completely distinct gene expression pattern. Here, we describe the Cpn transcriptome during the acute infection, differentiating “late” genes, which correlate to EB proteins, and “tardy” genes, which lead to EB mRNA. Expression profiles during iron mediated–persistence led us to propose the hypothesis that the transcriptomic “clock” is arrested during acute mid-cycle. Chlamydophila (Chlamydia) pneumoniae (Cpn) accounts for approximately one-tenth of the cases of community-acquired pneumonia worldwide, and persistent Cpn infections are thought to be associated with a variety of chronic diseases. Little is known about Cpn transcriptome changes during its biphasic developmental cycle (the acute infection) and persistence stages. Iron limitation, among several other treatments, has recently been shown to lead to persistent Cpn infection. How this pathogen reacts to iron-limiting host defense mechanisms is of great interest, as iron is an important factor affecting virulence. This article reports on the Cpn transcriptome during the developmental cycle and iron depletion–mediated persistence and reveals that genes coding for proteins of the infectious particle (the elementary body [EB]) were expressed constantly at the end of the cycle. In contrast, genes contributing to EB mRNA but not to EB protein showed an increasing expression at the end of the cycle. This suggested that most EB proteins are made in mid-cycle, and the redifferentiation process is initiated only by a limited number of genes. During iron depletion–mediated persistence, the Cpn transcriptome was altered in such a way that an arrest in Cpn gene expression can be proposed.
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Affiliation(s)
- André P Mäurer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Adrian Mehlitz
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Hans J Mollenkopf
- Microarray Core Facility, Max Planck Institute for Infection Biology, Berlin, Germany
| | - Thomas F Meyer
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
- * To whom correspondence should be addressed. E-mail:
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Abstract
During recent years there have been several incidents in which symptoms of disease have been linked to consumption of food contaminated by chemical substances (e.g., 2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD). Furthermore, outbreaks of infections in food-producing animals have attracted major attention regarding the safety of consumers, e.g., Bovine Spongiform Encephalitis (BSE) and influenza in chicken. As shown for several xenobiotics in an increasing number of experimental studies, even low-dose xenobiotic exposure may impair immune function over time, as well as microorganism virulence, resulting in more severe infectious diseases and associated complications. Moreover, during ongoing infection, xenobiotic uptake and distribution are often changed resulting in increased toxic insult to the host. The interactions among infectious agents, nutrients, and xenobiotics have thus become a developing concern and new avenue of research in food toxicology as well as in food-borne diseases. From a health perspective, in the risk assessment of xenobiotics in our food and environment, synergistic effects among microorganisms, nutrients, and xenobiotics will have to be considered. Otherwise, such effects may gradually change the disease panorama in society.
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Abstract
The diversity of infectious disease threats currently facing humanity is unprecedented because of the remarkable emergence and reemergence of pathogens worldwide. Because of population mobility, globalization of commerce and the food supply, and the effects of the HIV/AIDS pandemic, infections in the developing world must be addressed to prevent infections in industrialized countries. Because pathogens do not recognize national boundaries, the rapidity with which individuals can circumnavigate the globe incubating infections makes the control of communicable diseases an enormous challenge for governments as well as for the public and primary health care systems. A global strategy for dealing with infectious disease threats must be developed and implemented as soon as possible.
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Affiliation(s)
- Deirdre L Church
- Department of Pathology and Laboratory Medicine, University of Calgary, Faculty of Medicine, Health Sciences Centre, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada.
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Blanc P, Corsi AM, Gabbuti A, Peduzzi C, Meacci F, Olivieri F, Lauretani F, Francesco M, Ferrucci L. Chlamydia Pneumoniae Seropositivity and Cardiovascular Risk Factors: The InCHIANTI Study. J Am Geriatr Soc 2004; 52:1626-31. [PMID: 15450037 DOI: 10.1111/j.1532-5415.2004.52453.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES To assess the prevalence of Chlamydia pneumoniae (CP) seropositivity and test the hypothesis that CP infection (CPI) is associated with cardiovascular (CV) risk factors and levels of inflammatory biomarkers. DESIGN Cross-sectional survey. SETTING Representative sample of the residents of Greve in Chianti and Bagno a Ripoli, two small towns located in the Chianti geographic area (Tuscany, Italy). PARTICIPANTS A total of 1,304 (age-range: 20-103, 79% aged> or =65) participants of the InCHIANTI study. MEASUREMENTS CP seropositivity was assessed using immunofluorescence. Previous CPI was defined as immunoglobulin (Ig) G > or =1/16 and <1/256, and recent CPI was defined as IgG > or =1/512 or IgM > or =1/16. Inflammatory markers included interleukin (IL)-6, soluble IL-6 receptor (sIL-6r), tumor necrosis factor-alpha (TNF-alpha), IL-1beta, IL-1 receptor antagonist (IL-1ra), iron, ferritin, and C-reactive protein (CRP). CV risk factors included smoking, body mass index (BMI), lipid profile, and hypertension. RESULTS The prevalence of CP seropositivity was 75%, increased with age, and was higher in men than in women (P<.01). CPI was not associated with IL-1beta, IL-1ra, iron, ferritin, CRP, BMI, lipids, and smoking. After adjusting for age and sex, previous or recent CPI was associated with higher TNF-alpha (P<.01), IL-6 (P<.03), sIL-6R (P<.01), and hypertension (P<.02). In additional age and sex-adjusted models, the associations between CPI and TNF-alpha, IL-6, sIL-6r, and hypertension appeared to be mutually independent. CONCLUSION CP seropositivity is highly prevalent in the older population and is a significant, independent correlate of hypertension and circulating levels of TNF-alpha, IL-6, and sIL-6r.
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Affiliation(s)
- Pierluigi Blanc
- Infectious Diseases Section, Hospital SS Annunziata, Florence, Italy
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Sullivan JL. Re: Association between hemochromatosis (HFE) gene mutation carrier status and the risk of colon cancer. J Natl Cancer Inst 2003; 95:829-30; author reply 830. [PMID: 12783939 DOI: 10.1093/jnci/95.11.829-a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Heuer D, Brinkmann V, Meyer TF, Szczepek AJ. Expression and translocation of chlamydial protease during acute and persistent infection of the epithelial HEp-2 cells with Chlamydophila (Chlamydia) pneumoniae. Cell Microbiol 2003; 5:315-22. [PMID: 12713490 DOI: 10.1046/j.1462-5822.2003.00278.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chlamydial protease-like activity factor (CPAF) is secreted to the cytoplasm of the infected cells where it proteolytically cleaves eukaryotic transcription factor RFX5. Here, we determined the localization pattern of CPAF during the course of an acute and persistent in vitro infection of the epithelial cell line HEp-2 with Chlamydophila pneumoniae strain VR1310. Using immunoblotting, confocal microscopy and electron microscopy, we found CPAF in the inclusion lumen or associated with bacteria during the first 48 h of an acute infection. Seventy-two hours and later, CPAF was present predominantly in the cytoplasm of the infected cells. Translocation of CPAF into cytoplasm correlated in time with degradation of the transcription factor RFX5, as confirmed by immunoblotting. Interestingly, during the persistent infection induced by either IFN-gamma or iron limitation CPAF translocation to the cytoplasm was inhibited resulting in unaffected or only partially reduced levels of RFX5. Based on presented findings, we propose that CPAF translocation to the cytoplasm is separated from its production. The translocation mechanism appears to be fully active during an acute infection; however, it is fully or partially inhibited during persistent infection induced by IFN-gamma or by iron limitation respectively. Consequently, this work demonstrates the importance of subcellular localization of CPAF for the characteristics of chlamydial acute and persistent infection in epithelial HEp-2 cells.
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Affiliation(s)
- Dagmar Heuer
- Max-Planck Institute for Infection Biology, Department Molecular Biology, Schumannstr. 21/22, 10117 Berlin, Germany
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Weinberg ED. Laboratory Contributions to the Diagnosis of Common Iron-Loading Disorders and Anemias. Lab Med 2001. [DOI: 10.1309/gqlb-n6rd-u19w-uh19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Affiliation(s)
- Eugene D. Weinberg
- Department of Biology and Program in Medical Sciences, Indiana University, Bloomington, IN
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Al-Younes HM, Rudel T, Brinkmann V, Szczepek AJ, Meyer TF. Low iron availability modulates the course of Chlamydia pneumoniae infection. Cell Microbiol 2001; 3:427-37. [PMID: 11422085 DOI: 10.1046/j.1462-5822.2001.00125.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chlamydiae are obligate intracellular bacteria residing exclusively in host cell vesicles termed inclusions. We have investigated the effects of deferoxamine mesylate (DAM)-induced iron deficiency on the growth of Chlamydia pneumoniae and Chlamydia trachomatis serovar L2. In epithelial cells subjected to iron starvation and infected with either C. pneumoniae or C. trachomatis L2, small inclusions were formed, and the infectivity of chlamydial progeny was impaired. Moreover, for C. trachomatis L2, we observed a delay in homotypic fusion of inclusions. The inhibitory effects of DAM were reversed by adding exogenous iron-saturated transferrin, which restored the production of infectious chlamydiae. Electron microscopy examination of iron-deprived specimens revealed that the small inclusions contained reduced numbers of C. pneumoniae that were mostly reticulate bodies. We have previously reported specific accumulation of transferrin receptors (TfRs) around C. pneumoniae inclusions within cells grown under normal conditions. Using confocal and electron microscopy, we show here a remarkable increase in the amount of TfRs surrounding the inclusions in iron-starved cultures. It has been shown that iron is an essential factor in the growth and survival of C. trachomatis. Here, we postulate that, for C. pneumoniae also, iron is an indispensable element and that Chlamydia may use iron transport pathways of the host by attracting TfR to the phagosome.
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Affiliation(s)
- H M Al-Younes
- Department of Molecular Biology and Central Microscopy Unit, Max Planck Institute for Infection Biology, Schumannstrasse 21/22, D-10117 Berlin, Germany
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Ewald PW, Cochran GM. Chlamydia pneumoniae and cardiovascular disease: an evolutionary perspective on infectious causation and antibiotic treatment. J Infect Dis 2000; 181 Suppl 3:S394-401. [PMID: 10839723 DOI: 10.1086/315602] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Evolutionary considerations implicate infectious causation of atherosclerosis and help to resolve different risk factors as parts of an overall process of disease causation. An evolutionary approach also provides insight for the timing of research efforts to provide better control of pathogen evolution. In particular, evolutionary considerations emphasize the need to understand the transmissibility of Chlamydia pneumoniae from systemic infections in order to control the evolution of antibiotic resistance.
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Affiliation(s)
- P W Ewald
- Department of Biology, Amherst College, Amherst, MA 01002-5000, USA.
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