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Ullah I, Lang M. Key players in the regulation of iron homeostasis at the host-pathogen interface. Front Immunol 2023; 14:1279826. [PMID: 37942316 PMCID: PMC10627961 DOI: 10.3389/fimmu.2023.1279826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/03/2023] [Indexed: 11/10/2023] Open
Abstract
Iron plays a crucial role in the biochemistry and development of nearly all living organisms. Iron starvation of pathogens during infection is a striking feature utilized by a host to quell infection. In mammals and some other animals, iron is essentially obtained from diet and recycled from erythrocytes. Free iron is cytotoxic and is readily available to invading pathogens. During infection, most pathogens utilize host iron for their survival. Therefore, to ensure limited free iron, the host's natural system denies this metal in a process termed nutritional immunity. In this fierce battle for iron, hosts win over some pathogens, but others have evolved mechanisms to overdrive the host barriers. Production of siderophores, heme iron thievery, and direct binding of transferrin and lactoferrin to bacterial receptors are some of the pathogens' successful strategies which are highlighted in this review. The intricate interplay between hosts and pathogens in iron alteration systems is crucial for understanding host defense mechanisms and pathogen virulence. This review aims to elucidate the current understanding of host and pathogen iron alteration systems and propose future research directions to enhance our knowledge in this field.
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Affiliation(s)
- Inam Ullah
- CAS Center for Excellence in Biotic Interactions, College of Life Science, University of Chinese Academy of Sciences, Beijing, China
| | - Minglin Lang
- CAS Center for Excellence in Biotic Interactions, College of Life Science, University of Chinese Academy of Sciences, Beijing, China
- College of Life Science, Agricultural University of Hebei, Baoding, China
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Mostafa E, Ahmed FASMS, Yahia SH, Ibrahim AIM, Elbahaie ES. The effects of intracellular iron availability on the outcome of Toxoplasma gondii infection in mice. J Parasit Dis 2023; 47:608-618. [PMID: 37520204 PMCID: PMC10382456 DOI: 10.1007/s12639-023-01603-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/26/2023] [Indexed: 08/01/2023] Open
Abstract
Toxoplasma gondii (T. gondii) is a parasite that obtains the iron it needs for its own metabolism from the host-cell iron pool. In this work, we aimed to investigate if iron supplementation or deficiency affected the course of T. gondii infection. Eighty mice were divided into four groups, each with 20 animals: Group (I): Uninfected control group. Group (II): Infected control group: injected with Phosphate buffered saline. Group (III): Infected group: received iron sucrose treatment. Group (IV): Infected group: treated with deferoxamine. Quantitative PCR studies were performed on days 3 and 8 post-infection to detect the expression of iron metabolism genes (hamp and ferroprotin) and immune-histochemical analysis to study the percentage of TNF-α and TGF-β tissue expression. Iron supplementation induced progressions of infection evident by increased tissue expression of pro-inflammatory cytokine TNF-α and downregulation of TGF-β which is mostly linked to suppression of the inflammatory process caused by T. gondii. Increased expression of TGF-β and decreased expression of TNF-α was noticed when iron deprivation occurred. On day 3, we noticed increased expression in the hamp gene with iron supplementation while it decreases when the iron supply is low. On the contrary, iron deficiency increased ferroprotin gene expression whereas supplementing decreased it. On day 8, the level of expression of these genes returned to normal levels. These observations document the potential role of iron in controlling toxoplasmosis infection and indicate that the transcription of hamp and ferroprotin in T. gondii-infected cells appears to be regulated by a sophisticated indirect mechanism.
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Affiliation(s)
- Eman Mostafa
- Medical Parasitology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt
| | | | - Samah Hassan Yahia
- Medical Parasitology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt
| | | | - Enas Saed Elbahaie
- Medical Parasitology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt
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Sloan MA, Aghabi D, Harding CR. Orchestrating a heist: uptake and storage of metals by apicomplexan parasites. MICROBIOLOGY (READING, ENGLAND) 2021; 167. [PMID: 34898419 PMCID: PMC7612242 DOI: 10.1099/mic.0.001114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Megan A Sloan
- Wellcome Centre for Integrative Parasitology, Institute for Infection, Immunity and Inflammation, University of Glasgow, UK
| | - Dana Aghabi
- Wellcome Centre for Integrative Parasitology, Institute for Infection, Immunity and Inflammation, University of Glasgow, UK
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Hamed EFA, Mostafa NE, Fawzy EM, Ibrahim MN, Attia R, Salama MA. The delayed death-causing nature of Rosmarinus officinalis leaf extracts and their mixture within experimental chronic toxoplasmosis: Therapeutic and prophylactic implications. Acta Trop 2021; 221:105992. [PMID: 34089696 DOI: 10.1016/j.actatropica.2021.105992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 05/22/2021] [Accepted: 05/26/2021] [Indexed: 12/12/2022]
Abstract
BACKGROUND The restricted effect, significant toxicity, and emerging resistance of anti-toxoplasmosis synthetic agents impose the search for alternatives. The current research aimed to evaluate the prophylactic and therapeutic efficacy of Rosmarinus officinalis extracts and their mixtures against chronic murine toxoplasmosis and to clarify the phenomenon of delayed death. METHODS This research included two experimental designs, the first to test the preventive and curative efficacy of the extracts and the second to assess delayed death in mice infected with the ME49 strain of Toxoplasma gondii. The essential oils of the plant were analyzed by gas chromatography/mass spectrometry. RESULTS Treatment with a mixture of rosemary extracts displayed reduction rates of 81% for T. gondii cyst burden and 23% for cyst viability. The reinfected group with the pretreated cysts reported 93.4% reduction in cyst burden and 95.4% in cyst viability. Moreover, 90% reduction of the infectivity rate was obtained. The therapeutic efficacy of this mixture was superior to its valuable prophylactic effect. Histopathological examination of liver and brain tissue exhibited marked improvement. Both extracts possess free radical scavenging and antioxidant activities evidenced by high expression of iNOS stain. Our results were signified by low BAG-1 gene expression and massive mutilation of T. gondii cyst in the targeted group using scanning electron microscopy. Analysis of R. officinalis revealed the presence of isobornylformate as a novel ingredient. CONCLUSIONS R. officinalis displays a therapeutic rather than prophylactic potential, indicating the emergence of an effective safe alternative therapy.
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Oliveira MC, Coutinho LB, Almeida MPO, Briceño MP, Araujo ECB, Silva NM. The Availability of Iron Is Involved in the Murine Experimental Toxoplasma gondii Infection Outcome. Microorganisms 2020; 8:microorganisms8040560. [PMID: 32295126 PMCID: PMC7232304 DOI: 10.3390/microorganisms8040560] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/07/2020] [Accepted: 04/11/2020] [Indexed: 02/07/2023] Open
Abstract
Iron is an important constituent of our environment, being necessary for both mammalian and pathogenic protozoa survival. Iron-containing proteins exert a wide range of biological processes such as biodegradation and biosynthesis, as well as immune function, fetal development, and physical and mental well-being. This work aimed to investigate the effect of iron deprivation in Toxoplasma gondii infection outcome. C57BL/6 mice were orally infected with T. gondii and treated with an iron chelator, deferoxamine, or supplemented with iron (ferrous sulfate), and the parasitism as well as immunological and histological parameters were analyzed. It was observed that the infection increased iron accumulation in the organs, as well as systemically, and deferoxamine treatment diminished the iron content in serum samples and intestine. The deferoxamine treatment decreased the parasitism and inflammatory alterations in the small intestine and lung. Additionally, they partially preserved the Paneth cells and decreased the intestinal dysbiosis. The ferrous sulfate supplementation, despite not significantly increasing the parasite load in the organs, increased the inflammatory alterations in the liver. Together, our results suggest that iron chelation, which is commonly used to treat iron overload, could be a promising medicine to control T. gondii proliferation, mainly in the small intestine, and consequently inflammation caused by infection.
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Al-Sandaqchi AT, Brignell C, Collingwood JF, Geraki K, Mirkes EM, Kong K, Castellanos M, May ST, Stevenson CW, Elsheikha HM. Metallome of cerebrovascular endothelial cells infected with Toxoplasma gondii using μ-XRF imaging and inductively coupled plasma mass spectrometry. Metallomics 2019; 10:1401-1414. [PMID: 30183049 DOI: 10.1039/c8mt00136g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we measured the levels of elements in human brain microvascular endothelial cells (ECs) infected with T. gondii. ECs were infected with tachyzoites of the RH strain, and at 6, 24, and 48 hours post infection (hpi), the intracellular concentrations of elements were determined using a synchrotron-microfocus X-ray fluorescence microscopy (μ-XRF) system. This method enabled the quantification of the concentrations of Zn and Ca in infected and uninfected (control) ECs at sub-micron spatial resolution. T. gondii-hosting ECs contained less Zn than uninfected cells only at 48 hpi (p < 0.01). The level of Ca was not significantly different between infected and control cells (p > 0.05). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis revealed infection-specific metallome profiles characterized by significant increases in the intracellular levels of Zn, Fe, Mn and Cu at 48 hpi (p < 0.01), and significant reductions in the extracellular concentrations of Co, Cu, Mo, V, and Ag at 24 hpi (p < 0.05) compared with control cells. Zn constituted the largest part (74%) of the total metal composition (metallome) of the parasite. Gene expression analysis showed infection-specific upregulation in the expression of five genes, MT1JP, MT1M, MT1E, MT1F, and MT1X, belonging to the metallothionein gene family. These results point to a possible correlation between T. gondii infection and increased expression of MT1 isoforms and altered intracellular levels of elements, especially Zn and Fe. Taken together, a combined μ-XRF and ICP-MS approach is promising for studies of the role of elements in mediating host-parasite interaction.
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Affiliation(s)
- Alaa T Al-Sandaqchi
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Chris Brignell
- School of Mathematical Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | | | - Kalotina Geraki
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Evgeny M Mirkes
- Mathematics Department, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Kenny Kong
- School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Marcos Castellanos
- Nottingham Arabidopsis Stock Centre, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Sean T May
- Nottingham Arabidopsis Stock Centre, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Carl W Stevenson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire, LE12 5RD, UK.
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Almeida MPO, Ferro EAV, Briceño MPP, Oliveira MC, Barbosa BF, Silva NM. Susceptibility of human villous (BeWo) and extravillous (HTR-8/SVneo) trophoblast cells to Toxoplasma gondii infection is modulated by intracellular iron availability. Parasitol Res 2019; 118:1559-1572. [PMID: 30796516 DOI: 10.1007/s00436-019-06257-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022]
Abstract
Congenital toxoplasmosis is a serious health problem that can lead to miscarriage. HTR-8/SVneo is a first trimester extravillous trophoblast, while BeWo is a choriocarcinoma with properties of villous trophoblast cells. In the placenta, iron is taken up from Fe-transferrin through the transferrin receptor being the ion an important nutrient during pregnancy and also for Toxoplasma gondii proliferation. The aim of this study was to evaluate the role of iron in T. gondii proliferation in BeWo and HTR-8/SVneo cells and in human chorionic villous explants. The cells were infected with T. gondii, iron supplemented or deprived by holo-transferrin or deferoxamine, respectively, and parasite proliferation and genes related to iron balance were analyzed. It was verified that the addition of holo-transferrin increased, and DFO decreased the parasite multiplication in both trophoblastic cells, however, in a more expressive manner in HTR-8/SVneo, indicating that the parasite depends on iron storage in trophoblastic cells for its growth. Also, tachyzoites pretread with DFO proliferate normally in trophoblastic cells demonstrating that DFO itself does not interfere with parasite proliferation. Additionally, T. gondii infection induced enhancement in transferrin receptor mRNA expression levels in trophoblastic cells, and the expression was higher in HTR-8/SVneo compared with BeWo. Finally, DFO-treatment was able to reduce the parasite replication in villous explants. Thus, the iron supplementation can be a double-edged sword; in one hand, it could improve the supplement of an essential ion to embryo/fetus development, and on the other hand, could improve the parasite proliferation enhancing the risk of congenital infection.
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Affiliation(s)
- Marcos Paulo Oliveira Almeida
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Eloisa Amália Vieira Ferro
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Marisol Patricia Pallete Briceño
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Mário Cézar Oliveira
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Bellisa Freitas Barbosa
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Neide Maria Silva
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil.
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Abstract
Toxoplasma gondii is an obligate intracellular parasite belonging to the phylum Apicomplexa that infects all warm-blooded animals, including humans. T. gondii can replicate in every nucleated host cell by orchestrating metabolic interactions to derive crucial nutrients. In this review, we summarize the current status of known metabolic interactions of T. gondii with its host cell and discuss open questions and promising experimental approaches that will allow further dissection of the host-parasite interface and discovery of ways to efficiently target both tachyzoite and bradyzoite forms of T. gondii, which are associated with acute and chronic infection, respectively.
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Affiliation(s)
- Martin Blume
- NG2 - Metabolism of Microbial Pathogens, Robert Koch-Institute, Berlin, Germany
| | - Frank Seeber
- FG16 - Mycotic and Parasitic Agents and Mycobacteria, Robert Koch-Institute, Berlin, Germany
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9
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Cheeseman K, Weitzman JB. Host–parasite interactions: an intimate epigenetic relationship. Cell Microbiol 2015; 17:1121-32. [DOI: 10.1111/cmi.12471] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 05/28/2015] [Accepted: 06/01/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Kevin Cheeseman
- Sorbonne Paris Cité Epigenetics and Cell Fate UMR 7216 CNRS Université Paris Diderot Paris France
| | - Jonathan B. Weitzman
- Sorbonne Paris Cité Epigenetics and Cell Fate UMR 7216 CNRS Université Paris Diderot Paris France
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Cell death of gamma interferon-stimulated human fibroblasts upon Toxoplasma gondii infection induces early parasite egress and limits parasite replication. Infect Immun 2013; 81:4341-9. [PMID: 24042117 DOI: 10.1128/iai.00416-13] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The intracellular protozoan parasite Toxoplasma gondii is a major food-borne illness and opportunistic infection for the immunosuppressed. Resistance to Toxoplasma is dependent on gamma interferon (IFN-γ) activation of both hematopoietic and nonhematopoietic cells. Although IFN-γ-induced innate immunity in nonhematopoietic cells has been extensively studied in mice, it remains unclear what resistance mechanisms are relied on in nonhematopoietic human cells. Here, we report an IFN-γ-induced mechanism of resistance to Toxoplasma in primary human foreskin fibroblasts (HFFs) that does not depend on the deprivation of tryptophan or iron. In addition, infection is still controlled in HFFs deficient in the p65 guanylate binding proteins GBP1 or GBP2 and the autophagic protein ATG5. Resistance is coincident with host cell death that is not dependent on the necroptosis mediator RIPK3 or caspases and is correlated with early egress of the parasite before replication. This IFN-γ-induced cell death and early egress limits replication in HFFs and could promote clearance of the parasite by immune cells.
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Li C, Wang X, Li N, Wu C. Microarray analysis revealed that immunity-associated genes are primarily regulated by roxarsone in promoting broiler chicken (Gallus gallus domesticus) growth. Poult Sci 2012; 91:3184-90. [DOI: 10.3382/ps.2012-02392] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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da Costa-Silva TA, da Silva Meira C, Frazzatti-Gallina N, Pereira-Chioccola VL. Toxoplasma gondii antigens: recovery analysis of tachyzoites cultivated in Vero cell maintained in serum free medium. Exp Parasitol 2012; 130:463-9. [PMID: 22306070 DOI: 10.1016/j.exppara.2012.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 10/24/2011] [Accepted: 01/10/2012] [Indexed: 01/18/2023]
Abstract
Vero cells have been used successfully in Toxoplasma gondii maintenance. Medium supplementation for culture cells with fetal bovine serum is necessary for cellular growth. However, serum in these cultures presents disadvantages, such as the potential to induce hypersensitivity, variability of serum batches, possible presence of contaminants, and the high cost of good quality serum. Culture media formulated without any animal derived components, designed for serum-free growth of cell lines have been used successfully for different virus replication. The advantages of protozoan parasite growth in cell line cultures using serum-free medium remain poorly studied. Thus, this study was designed to determine whether T. gondii tachyzoites grown in Vero cell cultures in serum-free medium, after many passages, are able to maintain the same antigenic proprieties as those maintained in experimental mice. The standardization of Vero cell culture in serum-free medium for in vitro T. gondii tachyzoite production was performed establishing the optimal initial cell concentration for the confluent monolayer formation, which was 1×10(6) Vero cell culture as initial inoculum. The total confluent monolayer formatted after 96 h and the best amount of harvested tachyzoites was 2.1×10(7) using parasite inoculum of 1.5×10(6) after 7 days post-infection. The infectivity of tachyzoites released from Vero cells maintained in serum-free medium was evaluated using groups of Swiss mice infected with cell-culture tachyzoites. The parasite concentrations were similar to those for mice infected with tachyzoites collected from other infected mice. The data from both in vivo and in vitro experiments showed that in at least 30 culture cell passages, the parasites maintained the same infectivity as maintained in vivo. Another question was to know whether in the several continued passages, immunogenic progressive loss could occur. The nucleotide sequences studied were the same between the different passages, which could mean no change in their viability in the lysate antigen. Thus, the antigen production by cell culture has clear ethical and cost-saving advantages. Moreover, the use of culture media formulated without any human or animal derived components, designed for serum-free growth of cell lines, successfully produced tachyzoites especially for antigen production.
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Genome-wide expression analysis of roxarsone-stimulated growth of broiler chickens (Gallus gallus). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2011; 6:264-70. [PMID: 21652273 DOI: 10.1016/j.cbd.2011.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 05/17/2011] [Accepted: 05/17/2011] [Indexed: 11/21/2022]
Abstract
Roxarsone is a commonly used additive in chicken (Gallus gallus) industry. However, little is known on the intrinsic molecular mechanism via which the growth performance of birds improves. This study was therefore performed to investigate the expression profiles of genes induced by roxarsone. Fifty-six broiler chickens were divided into two groups, namely treated and untreated with roxarsone. The treated group was provided a diet of 45.4mg/kg roxarsone medication and the other group acted as control. Data analysis showed that roxarsone consistently and significantly (P<0.05) increased chicken growth performance. In addition to this a significant (P<0.05) increase of arsenic residue in liver has been seen. Microarray expression analysis of 8935 genes in liver showed that 22 genes (10 up- and 12 down-regulated) had altered expression throughout the experimental periods. Two novel genes (GenBank accession no. GU724343 and GU724344) were cloned through rapid amplification of cDNA ends (RACE). Gene GU724343 was predicted to encode an unidentified protein and the second gene GU724344 was presumed to encode a new member of immunoglobulin-like receptor (CHIR) family. Our results suggested for the first time that the role of roxarsone could be mainly to modify the expression levels of cell growth, immunity/defense and energy metabolism associated genes, as a result promoting animal growth. Further research on these genes should help to increase the knowledge of improving animal productivity safely and effectively.
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Abstract
Toxoplasma gondii is an obligate intracellular parasite that can infect virtually any nucleated cell. During invasion Toxoplasma creates the parasitophorous vacuole, a subcellular compartment that acts as an interface between the parasite and host, and serves as a platform for modulation of host cell functions that support parasite replication and infection. Spatial reorganization of host organelles and cytoskeleton around the parasitophorous vacuole are observed following entry, and recent evidence suggests this interior redecorating promotes parasite nutrient acquisition. New findings also reveal that Toxoplasma manipulates host signaling pathways by deploying parasite kinases and a phosphatase, including at least two that infiltrate the host nucleus. Toxoplasma infection additionally controls several cellular pathways to establish an anti-apoptotic environment, and subverts immune cells as a conduit for dissemination. In this review we discuss these recent developments in understanding how Toxoplasma achieves widespread success as a human and animal parasite by manipulating its host.
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Affiliation(s)
- J Laliberté
- Department of Microbiology and Immunology, University of Michigan Medical School, 1150 West Medical Center Drive, 5751 Medical Science Building II, Ann Arbor, Michigan 48109-0620, USA.
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15
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Fouts AE, Boothroyd JC. Infection with Toxoplasma gondii bradyzoites has a diminished impact on host transcript levels relative to tachyzoite infection. Infect Immun 2006; 75:634-42. [PMID: 17088349 PMCID: PMC1828502 DOI: 10.1128/iai.01228-06] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Toxoplasma gondii, an intracellular pathogen, has the potential to infect nearly every warm-blooded animal but rarely causes morbidity. The ability for the parasite to convert to the bradyzoite stage and live inside slow-growing cysts that can go unnoticed by the host immune system allows for parasite persistence for the life of the infected host. This intracellular survival likely necessitates host cell modulation, and tachyzoites are known to modify a number of signaling cascades within the host to promote parasite survival. Little is known, however, about how bradyzoites manipulate their host cell. Microarrays were used to profile the host transcriptional changes caused by bradyzoite infection and compared to those of tachyzoite-infected and uninfected hosts cells 2 days postinfection in vitro. Infection resulted in chemokine, cytokine, extracellular matrix, and growth factor transcript level changes. A small group of genes were specifically induced by tachyzoite infection, including granulocyte-macrophage colony-stimulating factor, BCL2-related protein A1, and interleukin-24. Bradyzoite infection yielded only about half the changes seen with tachyzoite infection, and those changes that did occur were almost all of lower magnitude than those induced by tachyzoites. These results suggest that bradyzoites lead a more stealthy existence within the infected host cell.
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Affiliation(s)
- A E Fouts
- Department of Microbiology and Immunology, Fairchild Building D305, 300 Pasteur Dr., Stanford University School of Medicine, Stanford, CA 94305-5124, USA
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Ong ST, Ho JZS, Ho B, Ding JL. Iron-withholding strategy in innate immunity. Immunobiology 2006; 211:295-314. [PMID: 16697921 DOI: 10.1016/j.imbio.2006.02.004] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Accepted: 02/14/2006] [Indexed: 10/24/2022]
Abstract
The knowledge of how organisms fight infections has largely been built upon the ability of host innate immune molecules to recognize microbial determinants. Although of overwhelming importance, pathogen recognition is but only one of the facets of innate immunity. A primitive yet effective antimicrobial mechanism which operates by depriving microbial organisms of their nutrients has been brought into the forefront of innate immunity once again. Such a tactic is commonly referred to as the iron-withholding strategy of innate immunity. In this review, we introduce various vertebrate iron-binding proteins and their invertebrate homologues, so as to impress upon readers an obscured arm of innate immune defense. An excellent comprehension of the mechanics of innate immunity paves the way for the possibility that novel antimicrobial therapeutics may emerge one day to overcome the prevalent antibiotic resistance in bacteria.
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Affiliation(s)
- Sek Tong Ong
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543
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