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MicroRNA-155 promotes autophagy to eliminate intracellular mycobacteria by targeting Rheb. PLoS Pathog 2013; 9:e1003697. [PMID: 24130493 PMCID: PMC3795043 DOI: 10.1371/journal.ppat.1003697] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 08/26/2013] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects one-third of the global population. It can live within macrophages owning to its ability to arrest phagolysosome biogenesis. Autophagy has recently been identified as an effective way to control the intracellular mycobacteria by enhancing phagosome maturation. In the present study, we demonstrate a novel role of miR-155 in regulating the autophagy-mediated anti-mycobacterial response. Both in vivo and in vitro studies showed that miR-155 expression was significantly enhanced after mycobacterial infection. Forced expression of miR-155 accelerated the autophagic response in macrophages, thus promoting the maturation of mycobacterial phagosomes and decreasing the survival rate of intracellular mycobacteria, while transfection with miR-155 inhibitor increased mycobacterial survival. However, macrophage-mediated mycobacterial phagocytosis was not affected after miR-155 overexpression or inhibition. Furthermore, blocking autophagy with specific inhibitor 3-methyladenine or silencing of autophagy related gene 7 (Atg7) reduced the ability of miR-155 to promote autophagy and mycobacterial elimination. More importantly, our study demonstrated that miR-155 bound to the 3′-untranslated region of Ras homologue enriched in brain (Rheb), a negative regulator of autophagy, accelerated the process of autophagy and sequential killing of intracellular mycobacteria by suppressing Rheb expression. Our results reveal a novel role of miR-155 in regulating autophagy-mediated mycobacterial elimination by targeting Rheb, and provide potential targets for clinical treatment. microRNA-155 (miR-155) plays an essential role in regulating the host immune response by post-transcriptionally repressing the expression of target genes. However, little is known regarding its activity in modulating autophagy, an important host defense mechanism against intracellular bacterial infection. Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects approximately one-third of the global population, and causes 1.5 million deaths annually. The present study explores a novel role of miR-155 in the host response against mycobacterial infection. Our data demonstrates that mycobacterial infection triggers the expression of miR-155, and the induction of miR-155 in turn activates autophagy by targeting Rheb, a negative regulator of autophagy. miR-155-promoted autophagy accelerates the maturation of the mycobacterial phagosome, thus decreasing the survival of intracellular mycobacteria in macrophages. These findings contribute to a better understanding of the host defense mechanisms against mycobacterial infection, providing useful information for development of potential therapeutic interventions against tuberculosis.
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102
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Vegh P, Foroushani ABK, Magee DA, McCabe MS, Browne JA, Nalpas NC, Conlon KM, Gordon SV, Bradley DG, MacHugh DE, Lynn DJ. Profiling microRNA expression in bovine alveolar macrophages using RNA-seq. Vet Immunol Immunopathol 2013; 155:238-44. [PMID: 24021155 DOI: 10.1016/j.vetimm.2013.08.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 08/06/2013] [Accepted: 08/13/2013] [Indexed: 11/17/2022]
Abstract
MicroRNAs (miRNAs) are important regulators of gene expression and are known to play a key role in regulating both adaptive and innate immunity. Bovine alveolar macrophages (BAMs) help maintain lung homeostasis and constitute the front line of host defense against several infectious respiratory diseases, such as bovine tuberculosis. Little is known, however, about the role miRNAs play in these cells. In this study, we used a high-throughput sequencing approach, RNA-seq, to determine the expression levels of known and novel miRNAs in unchallenged BAMs isolated from lung lavages of eight different healthy Holstein-Friesian male calves. Approximately 80 million sequence reads were generated from eight BAM miRNA Illumina sequencing libraries, and 80 miRNAs were identified as being expressed in BAMs at a threshold of at least 100 reads per million (RPM). The expression levels of miRNAs varied over a large dynamic range, with a few miRNAs expressed at very high levels (up to 800,000RPM), and the majority lowly expressed. Notably, many of the most highly expressed miRNAs in BAMs have known roles in regulating immunity in other species (e.g. bta-let-7i, bta-miR-21, bta-miR-27, bta-miR-99b, bta-miR-146, bta-miR-147, bta-miR-155 and bta-miR-223). The most highly expressed miRNA in BAMs was miR-21, which has been shown to regulate the expression of antimicrobial peptides in Mycobacterium leprae-infected human monocytes. Furthermore, the predicted target genes of BAM-expressed miRNAs were found to be statistically enriched for roles in innate immunity. In addition to profiling the expression of known miRNAs, the RNA-seq data was also analysed to identify potentially novel bovine miRNAs. One putatively novel bovine miRNA was identified. To the best of our knowledge, this is the first RNA-seq study to profile miRNA expression in BAMs and provides an important reference dataset for investigating the regulatory roles miRNAs play in this important immune cell type.
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Affiliation(s)
- Peter Vegh
- Animal & Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland; Smurfit Institute of Genetics, Trinity College, Dublin 2, Ireland
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103
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Harapan H, Fitra F, Ichsan I, Mulyadi M, Miotto P, Hasan NA, Calado M, Cirillo DM. The roles of microRNAs on tuberculosis infection: meaning or myth? Tuberculosis (Edinb) 2013; 93:596-605. [PMID: 24025365 DOI: 10.1016/j.tube.2013.08.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 08/05/2013] [Accepted: 08/06/2013] [Indexed: 02/06/2023]
Abstract
The central proteins for protection against tuberculosis are attributed to interferon-γ, tumor necrosis factor-α, interleukin (IL)-6 and IL-1β, while IL-10 primarily suppresses anti-mycobacterial responses. Several studies found alteration of expression profile of genes involved in anti-mycobacterial responses in macrophages and natural killer (NK) cells from active and latent tuberculosis and from tuberculosis and healthy controls. This alteration of cellular composition might be regulated by microRNAs (miRNAs). Albeit only 1% of the genomic transcripts in mammalian cells encode miRNA, they are predicted to control the activity of more than 60% of all protein-coding genes and they have a huge influence in pathogenesis theory, diagnosis and treatment approach to some diseases. Several miRNAs have been found to regulate T cell differentiation and function and have critical role in regulating the innate function of macrophages, dendritic cells and NK cells. Here, we have reviewed the role of miRNAs implicated in tuberculosis infection, especially related to their new roles in the molecular pathology of tuberculosis immunology and as new targets for future tuberculosis diagnostics.
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Affiliation(s)
- Harapan Harapan
- Medical Research Unit, School of Medicine, Syiah Kuala University, Banda Aceh, Indonesia; Tropical Disease Center, School of Medicine, Syiah Kuala University, Banda Aceh, Indonesia.
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104
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Aalaei-andabili SH, Rezaei N. Toll like receptor (TLR)-induced differential expression of microRNAs (MiRs) promotes proper immune response against infections: a systematic review. J Infect 2013; 67:251-64. [PMID: 23850616 DOI: 10.1016/j.jinf.2013.07.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/25/2013] [Accepted: 07/06/2013] [Indexed: 12/19/2022]
Abstract
Toll like receptors (TLRs) are one of the major families of pattern recognition receptors (PRRs). MicroRNAs (MiRs) are small noncoding RNAs with regulatory effects on biological process, and it has been recently shown that they can control inflammatory process and the response to an infection by modulating the function of TLRs. In this study, we designed a systematic review to clarify the reciprocal interaction between TLRs and MiRs, in order to identify possible future therapeutic targets and strategies. On the one hand, TLRs stimulation can change expression level of miRs in various ways, which can lead to modulating their effects. On the other hand, MiRs also influence the expression of TLRs and the intensity of the inflammatory reaction. We therefore conclude that the interaction between MiRs and TLRs is a key regulator of innate immune system. Investigations discovering therapeutic approaches by manipulation of miRs expression level may open a new approach for the treatment of inflammatory diseases.
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105
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Ghorpade DS, Holla S, Sinha AY, Alagesan SK, Balaji KN. Nitric oxide and KLF4 protein epigenetically modify class II transactivator to repress major histocompatibility complex II expression during Mycobacterium bovis bacillus Calmette-Guerin infection. J Biol Chem 2013; 288:20592-606. [PMID: 23733190 DOI: 10.1074/jbc.m113.472183] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pathogenic mycobacteria employ several immune evasion strategies such as inhibition of class II transactivator (CIITA) and MHC-II expression, to survive and persist in host macrophages. However, precise roles for specific signaling components executing down-regulation of CIITA/MHC-II have not been adequately addressed. Here, we demonstrate that Mycobacterium bovis bacillus Calmette-Guérin (BCG)-mediated TLR2 signaling-induced iNOS/NO expression is obligatory for the suppression of IFN-γ-induced CIITA/MHC-II functions. Significantly, NOTCH/PKC/MAPK-triggered signaling cross-talk was found critical for iNOS/NO production. NO responsive recruitment of a bifunctional transcription factor, KLF4, to the promoter of CIITA during M. bovis BCG infection of macrophages was essential to orchestrate the epigenetic modifications mediated by histone methyltransferase EZH2 or miR-150 and thus calibrate CIITA/MHC-II expression. NO-dependent KLF4 regulated the processing and presentation of ovalbumin by infected macrophages to reactive T cells. Altogether, our study delineates a novel role for iNOS/NO/KLF4 in dictating the mycobacterial capacity to inhibit CIITA/MHC-II-mediated antigen presentation by infected macrophages and thereby elude immune surveillance.
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Affiliation(s)
- Devram Sampat Ghorpade
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
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106
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Rebane A, Akdis CA. MicroRNAs: Essential players in the regulation of inflammation. J Allergy Clin Immunol 2013; 132:15-26. [PMID: 23726263 DOI: 10.1016/j.jaci.2013.04.011] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/02/2013] [Accepted: 04/04/2013] [Indexed: 12/16/2022]
Abstract
Regulation of inflammatory responses is ensured by coordinated control of gene expression in participating immune system and tissue cells. One group of gene expression regulators, the functions of which have recently been started to be uncovered in relation to any type of inflammatory condition, is a class of short single-stranded RNA molecules termed microRNAs (miRNAs). miRNAs function together with partner proteins and mainly cause gene silencing through degradation of target mRNAs or inhibition of translation. A particular miRNA can have hundreds of target genes, and thereby miRNAs together influence the expression of a large proportion of proteins. The role of miRNAs in the immune system has been extensively studied since the discovery of miRNAs in mammalian cells approximately 10 years ago. The purpose of the current review is to provide an overview on the functions of miRNAs in the regulation of inflammation, with a specific focus on the mechanisms of allergic inflammation. Because recent studies clearly demonstrate the presence of extracellular miRNAs in body fluids and propose the involvement of miRNAs in cell-cell communication, we will also highlight findings about functions of extracellular miRNAs. The possible use of miRNAs as biomarkers, as well as miRNA-related novel treatment modalities, might open a new future for the diagnosis and treatment of many inflammatory conditions, including allergic diseases.
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Affiliation(s)
- Ana Rebane
- Swiss Institute of Allergy and Asthma Research, University of Zurich, Davos, Switzerland.
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107
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Alteration of human macrophages microRNA expression profile upon infection with Mycobacterium tuberculosis. Int J Mycobacteriol 2013; 2:128-34. [PMID: 26785980 DOI: 10.1016/j.ijmyco.2013.04.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 04/20/2013] [Accepted: 04/22/2013] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Mycobacterium tuberculosis (Mtb) has evolved multiple mechanisms to manipulate its cellular niche for its own advantage. Many efforts have been made to understand basal mechanisms of mycobacterial infections. However, the underlying molecular regulation is not fully understood. Recently, a new class of non-coding, small RNAs, called microRNAs (miRNAs), has emerged as important regulators in biological processes, and their involvement in mycobacterial infection has been identified, thus opening a new field of research. METHODS This study aimed to determine by TaqMan Low Density Array the host genome-wide miRNA expression profile of primary human monocyte-derived macrophages (MDM) infected with two members of the Mtb complex: virulent Mtb H37Rv and the non-virulent vaccine strain Mycobacterium bovis Bacillus Calmette-Guerin (BCG) in comparison with chemically-inactivated Mtb bacilli. RESULTS The findings of this study showed that infection of MDM with H37Rv or BCG results in a signature of miRNA expression mostly overlapping between the two mycobacteria. A substantially different signature emerged from infection with killed virulent bacilli, suggesting an active influence of live intracellular bacteria on cellular miRNA metabolism. Specifically, Mtb induced miRNA signature is composed of miRNAs well established in immune regulation, miR-155 and miR-146a, as well as a set of miRNAs newly associated with Mtb infection: miR-145, miR-222(∗), miR-27a and miR-27b. All of these miRNAs are predicted to target important immune-related genes. CONCLUSIONS This study signifies the miRNA host response upon intracellular mycobacterial infection in macrophages, providing new aspects of regulation in host-pathogen interactions, at post-transcriptional levels.
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108
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Tili E, Michaille JJ, Croce CM. MicroRNAs play a central role in molecular dysfunctions linking inflammation with cancer. Immunol Rev 2013; 253:167-84. [PMID: 23550646 DOI: 10.1111/imr.12050] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Esmerina Tili
- Department of Molecular Virology; Immunology and Medical Genetics; The Ohio State University Medical Center; Comprehensive Cancer Center; Columbus; OH; USA
| | | | - Carlo M. Croce
- Department of Molecular Virology; Immunology and Medical Genetics; The Ohio State University Medical Center; Comprehensive Cancer Center; Columbus; OH; USA
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109
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Singh PK, Singh AV, Chauhan DS. Current understanding on micro RNAs and its regulation in response to Mycobacterial infections. J Biomed Sci 2013; 20:14. [PMID: 23448104 PMCID: PMC3599176 DOI: 10.1186/1423-0127-20-14] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/23/2013] [Indexed: 12/11/2022] Open
Abstract
MicroRNAs (miRNAs) are evolutionarily conserved, naturally abundant, small, regulatory non-coding RNAs that inhibit gene expression at the post-transcriptional level in a sequence-specific manner. Due to involvement in a broad range of biological processes and diseases, miRNAs are now commanding considerable attention. Although much of the focus has been on the role of miRNAs in different types of cancer, recent evidence also points to a critical role of miRNAs in infectious disease, including those of bacterial origin. Now, miRNAs research is exploring rapidly as a new thrust area of biomedical research with relevance to deadly bacterial diseases like Tuberculosis (caused by Mycobacterium tuberculosis). The purpose of this review is to highlight the current developments in area of miRNAs regulation in Mycobacterial diseases; and how this might influence the diagnosis, understanding of disease biology, control and management in the future.
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Affiliation(s)
- Pravin Kumar Singh
- Department of Microbiology & Molecular Biology, National JALMA Institute for Leprosy & Other Mycobacterial Diseases, Tajganj, Agra UP Pin- 282001, India
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110
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Sonic hedgehog-dependent induction of microRNA 31 and microRNA 150 regulates Mycobacterium bovis BCG-driven toll-like receptor 2 signaling. Mol Cell Biol 2012; 33:543-56. [PMID: 23166298 DOI: 10.1128/mcb.01108-12] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hedgehog (HH) signaling is a significant regulator of cell fate decisions during embryogenesis, development, and perpetuation of various disease conditions. Testing whether pathogen-specific HH signaling promotes unique innate recognition of intracellular bacteria, we demonstrate that among diverse Gram-positive or Gram-negative microbes, Mycobacterium bovis BCG, a vaccine strain, elicits a robust activation of Sonic HH (SHH) signaling in macrophages. Interestingly, sustained tumor necrosis factor alpha (TNF-α) secretion by macrophages was essential for robust SHH activation, as TNF-α(-/-) macrophages exhibited compromised ability to activate SHH signaling. Neutralization of TNF-α or blockade of TNF-α receptor signaling significantly reduced the infection-induced SHH signaling activation both in vitro and in vivo. Intriguingly, activated SHH signaling downregulated M. bovis BCG-mediated Toll-like receptor 2 (TLR2) signaling events to regulate a battery of genes associated with divergent functions of M1/M2 macrophages. Genome-wide expression profiling as well as conventional gain-of-function or loss-of-function analysis showed that SHH signaling-responsive microRNA 31 (miR-31) and miR-150 target MyD88, an adaptor protein of TLR2 signaling, thus leading to suppression of TLR2 responses. SHH signaling signatures could be detected in vivo in tuberculosis patients and M. bovis BCG-challenged mice. Collectively, these investigations identify SHH signaling to be what we believe is one of the significant regulators of host-pathogen interactions.
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111
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112
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Nazari-Jahantigh M, Wei Y, Noels H, Akhtar S, Zhou Z, Koenen RR, Heyll K, Gremse F, Kiessling F, Grommes J, Weber C, Schober A. MicroRNA-155 promotes atherosclerosis by repressing Bcl6 in macrophages. J Clin Invest 2012; 122:4190-202. [PMID: 23041630 DOI: 10.1172/jci61716] [Citation(s) in RCA: 406] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 08/20/2012] [Indexed: 12/14/2022] Open
Abstract
Macrophages in atherosclerotic plaques drive inflammatory responses, degrade lipoproteins, and phagocytose dead cells. MicroRNAs (miRs) control the differentiation and activity of macrophages by regulating the signaling of key transcription factors. However, the functional role of macrophage-related miRs in the immune response during atherogenesis is unknown. Here, we report that miR-155 is specifically expressed in atherosclerotic plaques and proinflammatory macrophages, where it was induced by treatment with mildly oxidized LDL (moxLDL) and IFN-γ. Leukocyte-specific Mir155 deficiency reduced plaque size and number of lesional macrophages after partial carotid ligation in atherosclerotic (Apoe-/-) mice. In macrophages stimulated with moxLDL/IFN-γ in vitro, and in lesional macrophages, loss of Mir155 reduced the expression of the chemokine CCL2, which promotes the recruitment of monocytes to atherosclerotic plaques. Additionally, we found that miR-155 directly repressed expression of BCL6, a transcription factor that attenuates proinflammatory NF-κB signaling. Silencing of Bcl6 in mice harboring Mir155-/- macrophages enhanced plaque formation and CCL2 expression. Taken together, these data demonstrated that miR-155 plays a key role in atherogenic programming of macrophages to sustain and enhance vascular inflammation.
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