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Laub MT, Typas A. Principles of bacterial innate immunity against viruses. Curr Opin Immunol 2024; 89:102445. [PMID: 39137494 DOI: 10.1016/j.coi.2024.102445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Revised: 07/29/2024] [Accepted: 07/30/2024] [Indexed: 08/15/2024]
Abstract
All organisms must defend themselves against viral predators. This includes bacteria, which harbor immunity factors such as restriction-modification systems and CRISPR-Cas systems. More recently, a plethora of additional defense systems have been identified, revealing a richer, more sophisticated immune system than previously appreciated. Some of these newly identified defense systems have distant homologs in mammals, suggesting an ancient evolutionary origin of some facets of mammalian immunity. An even broader conservation exists at the level of how these immunity systems operate. Here, we focus at this level, reviewing key principles and high-level attributes of innate immunity in bacteria that are shared with mammalian immunity, while also noting key differences, with a particular emphasis on how cells sense viral infection.
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Affiliation(s)
- Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Athanasios Typas
- European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg, Germany; European Molecular Biology Laboratory, Structural and Computational Biology Unit, Heidelberg, Germany.
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Bulgakova ID, Svitich OA, Zverev VV. Mechanisms of Toll-like receptor tolerance induced by microbial ligands. JOURNAL OF MICROBIOLOGY, EPIDEMIOLOGY AND IMMUNOBIOLOGY 2023. [DOI: 10.36233/0372-9311-323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Some microorganisms can develop tolerance. On the one hand, it allows pathogenic microbes to escape immune surveillance, on the other hand, it provides the possibility to microbiota representatives to colonize different biotopes and build a symbiotic relationship with the host. Complex regulatory interactions between innate and adaptive immune systems as well as stimulation by antigens help microbes control and maintain immunological tolerance. An important role in this process belongs to innate immune cells, which recognize microbial components through pattern-recognition receptors. Toll-like receptors (TLRs) represent the main class of these receptors. Despite the universality of the activated signaling pathways, different cellular responses are induced by interaction of TLRs with microbiota representatives and pathogenic microbes, and they vary during acute and chronic infection. The research on mechanisms underlying the development of TLR tolerance is significant, as the above receptors are involved in a wide range of infectious and noninfectious diseases; they also play an important role in development of allergic diseases, autoimmune diseases, and cancers. The knowledge of TLR tolerance mechanisms can be critically important for development of TLR ligand-based therapeutic agents for treatment and prevention of multiple diseases.
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Devenish LP, Mhlanga MM, Negishi Y. Immune Regulation in Time and Space: The Role of Local- and Long-Range Genomic Interactions in Regulating Immune Responses. Front Immunol 2021; 12:662565. [PMID: 34046034 PMCID: PMC8144502 DOI: 10.3389/fimmu.2021.662565] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/26/2021] [Indexed: 12/27/2022] Open
Abstract
Mammals face and overcome an onslaught of endogenous and exogenous challenges in order to survive. Typical immune cells and barrier cells, such as epithelia, must respond rapidly and effectively to encountered pathogens and aberrant cells to prevent invasion and eliminate pathogenic species before they become overgrown and cause harm. On the other hand, inappropriate initiation and failed termination of immune cell effector function in the absence of pathogens or aberrant tissue gives rise to a number of chronic, auto-immune, and neoplastic diseases. Therefore, the fine control of immune effector functions to provide for a rapid, robust response to challenge is essential. Importantly, immune cells are heterogeneous due to various factors relating to cytokine exposure and cell-cell interaction. For instance, tissue-resident macrophages and T cells are phenotypically, transcriptionally, and functionally distinct from their circulating counterparts. Indeed, even the same cell types in the same environment show distinct transcription patterns at the single cell level due to cellular noise, despite being robust in concert. Additionally, immune cells must remain quiescent in a naive state to avoid autoimmunity or chronic inflammatory states but must respond robustly upon activation regardless of their microenvironment or cellular noise. In recent years, accruing evidence from next-generation sequencing, chromatin capture techniques, and high-resolution imaging has shown that local- and long-range genome architecture plays an important role in coordinating rapid and robust transcriptional responses. Here, we discuss the local- and long-range genome architecture of immune cells and the resultant changes upon pathogen or antigen exposure. Furthermore, we argue that genome structures contribute functionally to rapid and robust responses under noisy and distinct cellular environments and propose a model to explain this phenomenon.
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Affiliation(s)
- Liam P Devenish
- Division of Chemical, Systems, and Synthetic Biology, Department of Integrative Biomedical Sciences, Institute of Infectious Disease & Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Musa M Mhlanga
- Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, Netherlands.,Epigenomics & Single Cell Biophysics Group, Department of Cell Biology, Radboud University, Nijmegen, Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Yutaka Negishi
- Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, Netherlands.,Epigenomics & Single Cell Biophysics Group, Department of Cell Biology, Radboud University, Nijmegen, Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
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Lee J, Geng S, Li S, Li L. Single Cell RNA-Seq and Machine Learning Reveal Novel Subpopulations in Low-Grade Inflammatory Monocytes With Unique Regulatory Circuits. Front Immunol 2021; 12:627036. [PMID: 33708217 PMCID: PMC7940189 DOI: 10.3389/fimmu.2021.627036] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
Subclinical doses of LPS (SD-LPS) are known to cause low-grade inflammatory activation of monocytes, which could lead to inflammatory diseases including atherosclerosis and metabolic syndrome. Sodium 4-phenylbutyrate is a potential therapeutic compound which can reduce the inflammation caused by SD-LPS. To understand the gene regulatory networks of these processes, we have generated scRNA-seq data from mouse monocytes treated with these compounds and identified 11 novel cell clusters. We have developed a machine learning method to integrate scRNA-seq, ATAC-seq, and binding motifs to characterize gene regulatory networks underlying these cell clusters. Using guided regularized random forest and feature selection, our method achieved high performance and outperformed a traditional enrichment-based method in selecting candidate regulatory genes. Our method is particularly efficient in selecting a few candidate genes to explain observed expression pattern. In particular, among 531 candidate TFs, our method achieves an auROC of 0.961 with only 10 motifs. Finally, we found two novel subpopulations of monocyte cells in response to SD-LPS and we confirmed our analysis using independent flow cytometry experiments. Our results suggest that our new machine learning method can select candidate regulatory genes as potential targets for developing new therapeutics against low grade inflammation.
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Affiliation(s)
- Jiyoung Lee
- Ph.D. Program in Genetics, Bioinformatics and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.,School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Shuo Geng
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Song Li
- Ph.D. Program in Genetics, Bioinformatics and Computational Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.,School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Liwu Li
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
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Toll-like Receptors and the Control of Immunity. Cell 2020; 180:1044-1066. [DOI: 10.1016/j.cell.2020.02.041] [Citation(s) in RCA: 567] [Impact Index Per Article: 141.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/02/2020] [Accepted: 02/18/2020] [Indexed: 12/14/2022]
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Leylek R, Idoyaga J. The versatile plasmacytoid dendritic cell: Function, heterogeneity, and plasticity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 349:177-211. [PMID: 31759431 DOI: 10.1016/bs.ircmb.2019.10.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Since their identification as the natural interferon-producing cell two decades ago, plasmacytoid dendritic cells (pDCs) have been attributed diverse functions in the immune response. Their most well characterized function is innate, i.e., their rapid and robust production of type-I interferon (IFN-I) in response to viruses. However, pDCs have also been implicated in antigen presentation, activation of adaptive immune responses and immunoregulation. The mechanisms by which pDCs enact these diverse functions are poorly understood. One central debate is whether these functions are carried out by different pDC subpopulations or by plasticity in the pDC compartment. This chapter summarizes the latest reports regarding pDC function, heterogeneity, cell conversion and environmentally influenced plasticity, as well as the role of pDCs in infection, autoimmunity and cancer.
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Affiliation(s)
- Rebecca Leylek
- Department of Microbiology and Immunology, and Immunology Program, Stanford University School of Medicine, Stanford, CA, United States
| | - Juliana Idoyaga
- Department of Microbiology and Immunology, and Immunology Program, Stanford University School of Medicine, Stanford, CA, United States.
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Ferrarelli LK. New connections: Decoding macrophages in disease. Sci Signal 2019. [DOI: 10.1126/scisignal.aax6493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Deciphering how macrophages are reprogrammed in disease may lead to better patient therapies.
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