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Aporta A, Arbues A, Aguilo JI, Monzon M, Badiola JJ, de Martino A, Ferrer N, Marinova D, Anel A, Martin C, Pardo J. Attenuated Mycobacterium tuberculosis SO2 vaccine candidate is unable to induce cell death. PLoS One 2012; 7:e45213. [PMID: 23028853 PMCID: PMC3446966 DOI: 10.1371/journal.pone.0045213] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 08/13/2012] [Indexed: 11/18/2022] Open
Abstract
It has been proposed that Mycobacterium tuberculosis virulent strains inhibit apoptosis and trigger cell death by necrosis of host macrophages to evade innate immunity, while non-virulent strains induce typical apoptosis activating a protective host response. As part of the characterization of a novel tuberculosis vaccine candidate, the M. tuberculosis phoP mutant SO2, we sought to evaluate its potential to induce host cell death. The parental M. tuberculosis MT103 strain and the current vaccine against tuberculosis Bacillus Calmette-Guérin (BCG) were used as comparators in mouse models in vitro and in vivo. Our data reveal that attenuated SO2 was unable to induce apoptotic events neither in mouse macrophages in vitro nor during lung infection in vivo. In contrast, virulent MT103 triggers typical apoptotic events with phosphatidylserine exposure, caspase-3 activation and nuclear condensation and fragmentation. BCG strain behaved like SO2 and did not induce apoptosis. A clonogenic survival assay confirmed that viability of BCG- or SO2-infected macrophages was unaffected. Our results discard apoptosis as the protective mechanism induced by SO2 vaccine and provide evidence for positive correlation between classical apoptosis induction and virulent strains, suggesting apoptosis as a possible virulence determinant during M. tuberculosis infection.
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Affiliation(s)
- Adriana Aporta
- Grupo Apoptosis, Inmunidad y Cáncer, Dpto. Bioquímica y Biología Molecular y Celular, Fac. Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | - Ainhoa Arbues
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública, Fac. Medicina, Universidad de Zaragoza, Zaragoza, Spain
- CIBER Enfermedades respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Juan I. Aguilo
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública, Fac. Medicina, Universidad de Zaragoza, Zaragoza, Spain
- CIBER Enfermedades respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Monzon
- Research Centre for Encephalopathies and Transmissible Emerging Diseases, Universidad de Zaragoza, Zaragoza, Spain
| | - Juan J. Badiola
- Research Centre for Encephalopathies and Transmissible Emerging Diseases, Universidad de Zaragoza, Zaragoza, Spain
| | | | - Nadia Ferrer
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública, Fac. Medicina, Universidad de Zaragoza, Zaragoza, Spain
| | - Dessislava Marinova
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública, Fac. Medicina, Universidad de Zaragoza, Zaragoza, Spain
- CIBER Enfermedades respiratorias, Instituto de Salud Carlos III, Madrid, Spain
| | - Alberto Anel
- Grupo Apoptosis, Inmunidad y Cáncer, Dpto. Bioquímica y Biología Molecular y Celular, Fac. Ciencias, Universidad de Zaragoza, Zaragoza, Spain
| | - Carlos Martin
- Grupo de Genética de Micobacterias, Dpto. Microbiología, Medicina Preventiva y Salud Pública, Fac. Medicina, Universidad de Zaragoza, Zaragoza, Spain
- CIBER Enfermedades respiratorias, Instituto de Salud Carlos III, Madrid, Spain
- Servicio de Microbiología, Hospital Universitario Miguel Servet, IIS Aragón, Zaragoza, Spain
| | - Julian Pardo
- Fundación Aragón I+D (ARAID), Gobierno de Aragón, Zaragoza, Spain
- Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza, Zaragoza, Spain
- Grupo Inmunidad Celular Efectora (ICE), Dpto. Bioquímica y Biología Molecular y Celular, Fac. Ciencias, Universidad de Zaragoza/IIS Aragón, Zaragoza, Spain
- * E-mail:
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302
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Host susceptibility to gram-negative pneumonia after lung contusion. J Trauma Acute Care Surg 2012; 72:614-22; discussion 622-3. [PMID: 22491544 DOI: 10.1097/ta.0b013e318243d9b1] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Lung contusion (LC) induces inflammation with high local concentrations of proinflammatory mediators stimulating chemotaxis and activation of neutrophils. LC is also a risk factor for development of pneumonia; however, the reason for this increased susceptibility is not clearly identified. We hypothesize that LC creates acute changes in the host pulmonary innate immune system that leads to vulnerability from a "second" hit bacterial infection. METHODS Female C57Bl/6 mice underwent LC injury at time -6 hours. At 0 hours, these mice were inoculated intratracheally with 1,000 colony forming unit (CFU) of Klebsiella pneumoniae (LC+Pneu) or vehicle (LC). Control animals underwent a sham LC injury followed by pneumonia (Sham+Pneu). Bronchoalveolar lavage (BAL) fluid and lung tissue specimens were collected. Lung bacteria levels were quantified by serial dilution, plating, and counting CFUs. Cytokine levels were assayed by ELISA. Cell type identification and quantification was performed using flow cytometry. RESULTS Survival at 72 hours was markedly different for the LC, Sham+Pneu, and LC+Pneu groups (100%, 80%, 20%, p < 0.05 Sham+Pneu vs. LC+Pneu). LC+Pneu animals had decreased pulmonary bacterial clearance at 24 hours compared with the Sham+Pneu group (4 × 10(7) vs. 8 × 10(6) CFUs, p < 0.05). BAL levels of IL-1β, IL-6, and keratinocyte chemoattractant were all significantly elevated in LC+Pneu mice compared with the Sham+Pneu group at 24 hours. Conversely, the Sham+Pneu mice had increased levels of macrophage inflammatory protein-2, total cells, macrophages, and neutrophils in BAL compared with the LC+Pneu group at 24 hours. LC+Pneu animals demonstrated changes in macrophage apoptosis and necrosis in BAL samples obtained 2 hours after induction of pneumonia when compared with the Sham+Pneu group. Both Sham+Pneu and LC+Pneu animals demonstrated an increase in the level of IL-10 in BAL fluid compared with LC animals. CONCLUSION Acute inflammation after LC acts to modulate the presence of inflammatory cells necessary to combat gram-negative bacteria. This results in decreased bacterial clearance and increased mortality from pneumonia.
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Virus-like particle-induced protection against MRSA pneumonia is dependent on IL-13 and enhancement of phagocyte function. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 181:196-210. [PMID: 22642909 PMCID: PMC3388150 DOI: 10.1016/j.ajpath.2012.03.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 02/14/2012] [Accepted: 03/22/2012] [Indexed: 12/23/2022]
Abstract
The importance of the priming of the lung environment by past infections is being increasingly recognized. Exposure to any given antigen can either improve or worsen the outcome of subsequent lung infections, depending on the immunological history of the host. Thus, an ability to impart transient alterations in the lung environment in anticipation of future insult could provide an important novel therapy for emerging infectious diseases. In this study, we show that nasal administration of virus-like particles (VLPs) before, or immediately after, lethal challenge with methicillin-resistant Staphylococcus aureus (MRSA) of mice i) ensures complete recovery from lung infection and near absolute clearance of bacteria within 12 hours of challenge, ii) reduces host response-induced lung tissue damage, iii) promotes recruitment and efficient bacterial clearance by neutrophils and CD11c+ cells, and iv) protects macrophages from MRSA-induced necrosis. VLP-mediated protection against MRSA relied on innate immunity. Complete recovery occurred in VLP-dosed mice with severe combined immunodeficiency, but not in wild-type mice depleted of either Ly6G+ or CD11c+ cells. Early IL-13 production associated with VLP-induced CD11c+ cells was essential for VLP-induced protection. These results indicate that VLP-induced alteration of the lung environment protects the host from lethal MRSA pneumonia by enhancing phagocyte recruitment and killing and by reducing inflammation-induced tissue damage via IL-13–dependent mechanisms.
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304
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Mahajan S, Dkhar HK, Chandra V, Dave S, Nanduri R, Janmeja AK, Agrewala JN, Gupta P. Mycobacterium tuberculosis modulates macrophage lipid-sensing nuclear receptors PPARγ and TR4 for survival. THE JOURNAL OF IMMUNOLOGY 2012; 188:5593-603. [PMID: 22544925 DOI: 10.4049/jimmunol.1103038] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mycobacterium tuberculosis-macrophage interactions are key to pathogenesis and clearance of these bacteria. Although interactions between M. tuberculosis-associated lipids and TLRs, non-TLRs, and opsonic receptors have been investigated, interactions of these lipids and infected macrophage lipid repertoire with lipid-sensing nuclear receptors expressed in macrophages have not been addressed. In this study, we report that M. tuberculosis-macrophage lipids can interact with host peroxisome proliferator-activated receptor γ and testicular receptor 4 to ensure survival of the pathogen by modulating macrophage function. These two lipid-sensing nuclear receptors create a foamy niche within macrophage by modulating oxidized low-density lipoprotein receptor CD36, phagolysosomal maturation block by induction of IL-10, and a blunted innate response by alternative polarization of the macrophages, which leads to survival of M. tuberculosis. These results also suggest possible heterologous ligands for peroxisome proliferator-activated receptor γ and testicular receptor 4 and are suggestive of adaptive or coevolution of the host and pathogen. Relative mRNA expression levels of these receptors in PBMCs derived from clinical samples convincingly implicate them in tuberculosis susceptibility. These observations expose a novel paradigm in the pathogenesis of M. tuberculosis amenable for pharmacological modulation.
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Affiliation(s)
- Sahil Mahajan
- Institute of Microbial Technology, Chandigarh 160036, India
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305
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Ramakrishnan L. Revisiting the role of the granuloma in tuberculosis. Nat Rev Immunol 2012; 12:352-66. [PMID: 22517424 DOI: 10.1038/nri3211] [Citation(s) in RCA: 561] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The granuloma, which is a compact aggregate of immune cells, is the hallmark structure of tuberculosis. It is historically regarded as a host-protective structure that 'walls off' the infecting mycobacteria. This Review discusses surprising new discoveries--from imaging studies coupled with genetic manipulations--that implicate the innate immune mechanisms of the tuberculous granuloma in the expansion and dissemination of infection. It also covers why the granuloma can fail to eradicate infection even after adaptive immunity develops. An understanding of the mechanisms and impact of tuberculous granuloma formation can guide the development of therapies to modulate granuloma formation. Such therapies might be effective for tuberculosis as well as for other granulomatous diseases.
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Affiliation(s)
- Lalita Ramakrishnan
- Department of Microbiology, University of Washington, Seattle, Washington 98195, USA.
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306
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Iona E, Pardini M, Gagliardi MC, Colone M, Stringaro AR, Teloni R, Brunori L, Nisini R, Fattorini L, Giannoni F. Infection of human THP-1 cells with dormant Mycobacterium tuberculosis. Microbes Infect 2012; 14:959-67. [PMID: 22546526 DOI: 10.1016/j.micinf.2012.04.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 03/08/2012] [Accepted: 04/03/2012] [Indexed: 11/29/2022]
Abstract
Dormant, non-replicating Mycobacterium tuberculosis H37Rv strain cultured in hypoxic conditions was used to infect THP-1 cells. CFUs counting, Kinyoun staining and electron microscopy showed that dormant bacilli infected THP-1 cells at a rate similar to replicating M. tuberculosis, but failed to grow during the first 6 days of infection. The absence of growth was specific to the intracellular compartment, as demonstrated by efficient growth in liquid medium. Quantification of β-actin mRNA recovered from infected cells showed that, in contrast with log-phase bacteria, infection with dormant bacilli determined a reduced THP-1 cell death. Gene expression of intracellular non-replicating bacteria showed a pattern typical of a dormant state. Intracellular dormant bacteria induced the activation of genes associated to a proinflammatory response in THP-1 cells. Though, higher levels of TNFα, IL-1β and IL-8 mRNAs compared to aerobic H37Rv infected cells were not paralleled by increased cytokine accumulation in the supernatants. Moreover, dormant bacilli induced a higher expression of inducible cox-2 gene, accompanied by increased PGE2 secretion. Overall, our data describe a new model of in vitro infection using dormant M. tuberculosis that could provide the basis for understanding how non-replicating bacilli survive intracellularly and influence the maintenance of the hypoxic granuloma.
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Affiliation(s)
- Elisabetta Iona
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy
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307
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Dushkin MI. Macrophage/foam cell is an attribute of inflammation: Mechanisms of formation and functional role. BIOCHEMISTRY (MOSCOW) 2012; 77:327-38. [DOI: 10.1134/s0006297912040025] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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308
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MacHugh DE, Taraktsoglou M, Killick KE, Nalpas NC, Browne JA, DE Park S, Hokamp K, Gormley E, Magee DA. Pan-genomic analysis of bovine monocyte-derived macrophage gene expression in response to in vitro infection with Mycobacterium avium subspecies paratuberculosis. Vet Res 2012; 43:25. [PMID: 22455317 PMCID: PMC3411445 DOI: 10.1186/1297-9716-43-25] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/28/2012] [Indexed: 01/01/2023] Open
Abstract
Mycobacterium avium subspecies paratuberculosis is the causative agent of Johne's disease, an intestinal disease of ruminants with major economic consequences. Infectious bacilli are phagocytosed by host macrophages upon exposure where they persist, resulting in lengthy subclinical phases of infection that can lead to immunopathology and disease dissemination. Consequently, analysis of the macrophage transcriptome in response to M. avium subsp. paratuberculosis infection can provide valuable insights into the molecular mechanisms that underlie Johne's disease. Here, we investigate pan-genomic gene expression in bovine monocyte-derived macrophages (MDM) purified from seven age-matched females, in response to in vitro infection with M. avium subsp. paratuberculosis (multiplicity of infection 2:1) at intervals of 2 hours, 6 hours and 24 hours post-infection (hpi). Differentially expressed genes were identified by comparing the transcriptomes of the infected MDM to the non-infected control MDM at each time point (adjusted P-value threshold ≤ 0.10). 1050 differentially expressed unique genes were identified 2 hpi, with 974 and 78 differentially expressed unique genes detected 6 and 24 hpi, respectively. Furthermore, in the infected MDM the number of upregulated genes exceeded the number of downregulated genes at each time point, with the fold-change in expression for the upregulated genes markedly higher than that for the downregulated genes. Inspection and systems biology analysis of the differentially expressed genes revealed an enrichment of genes involved in the inflammatory response, cell signalling pathways and apoptosis. The transcriptional changes associated with cellular signalling and the inflammatory response may reflect different immuno-modulatory mechanisms that underlie host-pathogen interactions during infection.
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Affiliation(s)
- David E MacHugh
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
- UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Maria Taraktsoglou
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Kate E Killick
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Nicolas C Nalpas
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - John A Browne
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Stephen DE Park
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Karsten Hokamp
- Smurfit Institute of Genetics, Trinity College Dublin, Trinity College, Belfield, Dublin 2, Ireland
| | - Eamonn Gormley
- Tuberculosis Diagnostics and Immunology Research Centre, UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - David A Magee
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland
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309
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Obregón-Henao A, Duque-Correa MA, Rojas M, García LF, Brennan PJ, Ortiz BL, Belisle JT. Stable extracellular RNA fragments of Mycobacterium tuberculosis induce early apoptosis in human monocytes via a caspase-8 dependent mechanism. PLoS One 2012; 7:e29970. [PMID: 22253841 PMCID: PMC3253812 DOI: 10.1371/journal.pone.0029970] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 12/10/2011] [Indexed: 01/24/2023] Open
Abstract
The molecular basis of pathogen-induced host cell apoptosis is well characterized for a number of microorganisms. Mycobacterium tuberculosis is known to induce apoptosis and it was shown that live but not heat killed M. tuberculosis stimulates this biological pathway in monocytes. The dependence of this activity on live bacilli led us to hypothesize that products released or secreted by M. tuberculosis are the primary apoptotic factors for human monocytes. Thus, the culture filtrate of in vitro grown M. tuberculosis strain H37Rv was fractioned by conventional chromatography and the apoptosis-inducing activity of individual fractions was measured on human monocytes. The tests employed included measurement of cell membrane damage, caspase activation, and cytokine release. Small molecular weight RNAs of M. tuberculosis were recognized as the predominant apoptosis inducing factors. The RNA was comprised primarily of tRNA and rRNA fragments that stably accumulate in the culture filtrate during early log-phase growth. The RNA fragments signaled through a caspase-8 dependent, caspase-1 and TNF-α independent pathway that ultimately compromised the human monocytes' ability to control M. tuberculosis infection. These studies provide the first report of bacterial RNA inducing apoptosis. They also provide a foundation to pursue pathways for secretion or release of nucleic acids from M. tuberculosis and the impact of secreted RNA fragments on pathogenesis.
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Affiliation(s)
- Andrés Obregón-Henao
- Grupo de Inmunología Celular e Inmunogenética, Universidad de Antioquia, Medellín, Colombia
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - María A. Duque-Correa
- Grupo de Inmunología Celular e Inmunogenética, Universidad de Antioquia, Medellín, Colombia
| | - Mauricio Rojas
- Grupo de Inmunología Celular e Inmunogenética, Universidad de Antioquia, Medellín, Colombia
| | - Luis F. García
- Grupo de Inmunología Celular e Inmunogenética, Universidad de Antioquia, Medellín, Colombia
| | - Patrick J. Brennan
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Blanca L. Ortiz
- Grupo de Inmunología Celular e Inmunogenética, Universidad de Antioquia, Medellín, Colombia
| | - John T. Belisle
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
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Abstract
Caspases are aspartate-specific cysteine proteases that have an essential role in apoptosis and inflammation, and contribute to the maintenance of homeostasis in the intestine. These facts, together with the knowledge that caspases are implicated in host-microbe crosstalk, prompted us to investigate the effect of caspase (Casp)1, -3 and -7 deficiency on the composition of the murine gut microbiota. We observed significant changes in the abundance of the Firmicutes and Bacteroidetes phyla, in particular the Lachnospiraceae, Porphyromonodaceae and Prevotellacea families, when comparing Casp-1, -7 and -3 knockout mice with wild-type mice. Our data point toward an intricate relationship between these caspases and the composition of the murine gut microflora.
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312
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Wang C, Yang S, Sun G, Tang X, Lu S, Neyrolles O, Gao Q. Comparative miRNA expression profiles in individuals with latent and active tuberculosis. PLoS One 2011; 6:e25832. [PMID: 22003408 PMCID: PMC3189221 DOI: 10.1371/journal.pone.0025832] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 09/12/2011] [Indexed: 01/04/2023] Open
Abstract
The mechanism of latent tuberculosis (TB) infection remains elusive. Several host factors that are involved in this complex process were previously identified. Micro RNAs (miRNAs) are endogenous ∼22 nt RNAs that play important regulatory roles in a wide range of biological processes. Several studies demonstrated the clinical usefulness of miRNAs as diagnostic or prognostic biomarkers in various malignancies and in a few nonmalignant diseases. To study the role of miRNAs in the transition from latent to active TB and to discover candidate biomarkers of this transition, we used human miRNA microarrays to probe the transcriptome of peripheral blood mononuclear cells (PBMCs) in patients with active TB, latent TB infection (LTBI), and healthy controls. Using the software package BRB Array Tools for data analyses, 17 miRNAs were differentially expressed between the three groups (P<0.01). Hierarchical clustering of the 17 miRNAs expression profiles showed that individuals with active TB clustered independently of individuals with LTBI or from healthy controls. Using the predicted target genes and previously published genome-wide transcriptional profiles, we constructed the regulatory networks of miRNAs that were differentially expressed between active TB and LTBI. The regulatory network revealed that several miRNAs, with previously established functions in hematopoietic cell differentiation and their target genes may be involved in the transition from latent to active TB. These results increase the understanding of the molecular basis of LTBI and confirm that some miRNAs may control gene expression of pathways that are important for the pathogenesis of this infectious disease.
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Affiliation(s)
- Chuan Wang
- Key Laboratory of Medical Molecular Virology and Institute of Biomedical Sciences, Fudan University, Shanghai, China
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313
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Sharbati J, Lewin A, Kutz-Lohroff B, Kamal E, Einspanier R, Sharbati S. Integrated microRNA-mRNA-analysis of human monocyte derived macrophages upon Mycobacterium avium subsp. hominissuis infection. PLoS One 2011; 6:e20258. [PMID: 21629653 PMCID: PMC3101234 DOI: 10.1371/journal.pone.0020258] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 04/22/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Many efforts have been made to understand basal mechanisms of mycobacterial infections. Macrophages are the first line of host immune defence to encounter and eradicate mycobacteria. Pathogenic species have evolved different mechanisms to evade host response, e.g. by influencing macrophage apoptotic pathways. However, the underlying molecular regulation is not fully understood. A new layer of eukaryotic regulation of gene expression is constituted by microRNAs. Therefore, we present a comprehensive study for identification of these key regulators and their targets in the context of host macrophage response to mycobacterial infections. METHODOLOGY/PRINCIPAL FINDINGS We performed microRNA as well as mRNA expression analysis of human monocyte derived macrophages infected with several Mycobacterium avium hominissuis strains by means of microarrays as well as quantitative reverse transcription PCR (qRT-PCR). The data revealed the ability of all strains to inhibit apoptosis by transcriptional regulation of BCL2 family members. Accordingly, at 48 h after infection macrophages infected with all M. avium strains showed significantly decreased caspase 3 and 7 activities compared to the controls. Expression of let-7e, miR-29a and miR-886-5p were increased in response to mycobacterial infection at 48 h. The integrated analysis of microRNA and mRNA expression as well as target prediction pointed out regulative networks identifying caspase 3 and 7 as potential targets of let-7e and miR-29a, respectively. Consecutive reporter assays verified the regulation of caspase 3 and 7 by these microRNAs. CONCLUSIONS/SIGNIFICANCE We show for the first time that mycobacterial infection of human macrophages causes a specific microRNA response. We furthermore outlined a regulatory network of potential interactions between microRNAs and mRNAs. This study provides a theoretical concept for unveiling how distinct mycobacteria could manipulate host cell response. In addition, functional relevance was confirmed by uncovering the control of major caspases 3 and 7 by let-7e and miR-29a, respectively.
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Affiliation(s)
- Jutta Sharbati
- Institute of Veterinary Biochemistry, Freie Universitaet Berlin, Berlin, Germany.
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