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Asiaee A, Abrams ZB, Pua HH, Coombes KR. Transcriptome Complexity Disentangled: A Regulatory Molecules Approach. bioRxiv 2024:2023.04.17.537241. [PMID: 37131792 PMCID: PMC10153180 DOI: 10.1101/2023.04.17.537241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Transcription factors (TFs) and microRNAs (miR-NAs) are fundamental regulators of gene expression, cell state, and biological processes. This study investigated whether a small subset of TFs and miRNAs could accurately predict genome-wide gene expression. We analyzed 8895 samples across 31 cancer types from The Cancer Genome Atlas and identified 28 miRNA and 28 TF clusters using unsupervised learning. Medoids of these clusters could differentiate tissues of origin with 92.8% accuracy, demonstrating their biological relevance. We developed Tissue-Agnostic and Tissue-Aware models to predict 20,000 gene expressions using the 56 selected medoid miR-NAs and TFs. The Tissue-Aware model attained an R 2 of 0.70 by incorporating tissue-specific information. Despite measuring only 1/400th of the transcriptome, the prediction accuracy was comparable to that achieved by the 1000 landmark genes. This suggests the transcriptome has an intrinsically low-dimensional structure that can be captured by a few regulatory molecules. Our approach could enable cheaper transcriptome assays and analysis of low-quality samples. It also provides insights into genes that are heavily regulated by miRNAs/TFs versus alternative mechanisms. However, model transportability was impacted by dataset discrepancies, especially in miRNA distribution. Overall, this study demonstrates the potential of a biology-guided approach for robust transcriptome representation.
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2
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Ransom MA, Blatt AM, Pua HH, Sucre JMS. The emerging role of extracellular vesicles in bronchopulmonary dysplasia. Am J Physiol Lung Cell Mol Physiol 2024; 326:L517-L523. [PMID: 38469633 DOI: 10.1152/ajplung.00244.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 03/01/2024] [Accepted: 03/02/2024] [Indexed: 03/13/2024] Open
Abstract
Extracellular vesicle (EV) biology in neonatal lung development and disease is a rapidly growing area of investigation. Although EV research in the neonatal population lags behind EV research in adult lung diseases, recent discoveries demonstrate promise in furthering our understanding of the pathophysiology of bronchopulmonary dysplasia and the potential use of EVs in the clinical setting, as both biomarkers and therapeutic agents. This review article explores some of the recent advances in this field and our evolving knowledge of the role of EVs in bronchopulmonary dysplasia.
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Affiliation(s)
- Meaghan A Ransom
- Department of Pediatrics, Vanderbilt University Medical Center; Nashville, Tennessee, United States
| | - Alexander M Blatt
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Heather H Pua
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Vanderbilt Center for Immunobiology and Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Jennifer M S Sucre
- Department of Pediatrics, Vanderbilt University Medical Center; Nashville, Tennessee, United States
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States
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3
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Sprenkle NT, Winn NC, Bunn KE, Zhao Y, Park DJ, Giese BG, Karijolich JJ, Ansel KM, Serezani CH, Hasty AH, Pua HH. The miR-23-27-24 clusters drive lipid-associated macrophage proliferation in obese adipose tissue. Cell Rep 2023; 42:112928. [PMID: 37542720 PMCID: PMC10712211 DOI: 10.1016/j.celrep.2023.112928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 06/19/2023] [Accepted: 07/17/2023] [Indexed: 08/07/2023] Open
Abstract
Identifying molecular circuits that control adipose tissue macrophage (ATM) function is necessary to understand how ATMs contribute to tissue homeostasis and obesity-induced insulin resistance. In this study, we find that mice with a myeloid-specific knockout of the miR-23-27-24 clusters of microRNAs (miRNAs) gain less weight on a high-fat diet but exhibit worsened glucose and insulin tolerance. Analysis of ATMs from these mice shows selectively reduced numbers and proliferation of a recently reported subset of lipid-associated CD9+Trem2+ ATMs (lipid-associated macrophages [LAMs]). Leveraging the role of miRNAs to control networks of genes, we use RNA sequencing (RNA-seq), functional screens, and biochemical assays to identify candidate target transcripts that regulate proliferation-associated signaling. We determine that miR-23 directly targets the mRNA of Eif4ebp2, a gene that restricts protein synthesis and proliferation in macrophages. Altogether, our study demonstrates that control of proliferation of a protective subset of LAMs by noncoding RNAs contributes to protection against diet-induced obesity metabolic dysfunction.
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Affiliation(s)
- Neil T Sprenkle
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Nathan C Winn
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Kaitlyn E Bunn
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Yang Zhao
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Deborah J Park
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Brenna G Giese
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John J Karijolich
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Center for Immunobiology and Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanerbilt-Ingram Cancer Center, Nashville, TN, USA
| | - K Mark Ansel
- Department of Microbiology and Immunology and Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA, USA
| | - C Henrique Serezani
- Vanderbilt Center for Immunobiology and Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA; Division of Infectious Diseases, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alyssa H Hasty
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA; Vanderbilt Center for Immunobiology and Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA; Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Heather H Pua
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Center for Immunobiology and Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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4
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Ransom MA, Bunn KE, Negretti NM, Jetter CS, Bressman ZJ, Sucre JMS, Pua HH. Developmental trajectory of extracellular vesicle characteristics from the lungs of preterm infants. Am J Physiol Lung Cell Mol Physiol 2023; 324:L385-L392. [PMID: 36719083 PMCID: PMC10026990 DOI: 10.1152/ajplung.00389.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023] Open
Abstract
Extracellular vesicles (EVs) are secreted lipid-enclosed particles that have emerged as potential biomarkers and therapeutic agents in lung disease, including bronchopulmonary dysplasia (BPD), a leading complication of preterm birth. Many unanswered questions remain about the content and cargo of EVs in premature infants and their role in lung development. To characterize EVs during human lung development, tracheal aspirates were collected from premature neonates between 22 and 35 wk gestational age and analyzed via nanoparticle tracking analysis, electron microscopy, and bead-based flow cytometry. EVs were detectable across late canalicular through saccular stages of lung development, demonstrating larger sizes earlier in gestation. EVs contained an abundance of the EV-enriched tetraspanins CD9, CD63, and CD81, as well as epithelial cell and immune cell markers. Increases in select surface proteins (CD24 and CD14) on EVs were associated with gestational age and with the risk of BPD. Finally, query of expression data obtained from epithelial cells in a single-cell atlas of murine lung development found that epithelial EV marker expression also changes with developmental time. Together, these data demonstrate an association between EV profile and lung development and provide a foundation for future functional classification of EVs, with the goal of determining their role in cell signaling during development and harnessing their potential as a new therapeutic target in BPD.
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Affiliation(s)
- Meaghan A Ransom
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Kaitlyn E Bunn
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Nicholas M Negretti
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Christopher S Jetter
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Zachary J Bressman
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | - Jennifer M S Sucre
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, United States
| | - Heather H Pua
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Vanderbilt Center for Immunobiology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
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5
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Sprenkle NT, Serezani CH, Pua HH. MicroRNAs in Macrophages: Regulators of Activation and Function. J Immunol 2023; 210:359-368. [PMID: 36724439 PMCID: PMC10316964 DOI: 10.4049/jimmunol.2200467] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/13/2022] [Indexed: 02/03/2023]
Abstract
Macrophages are sentinels of the innate immune system that maintain tissue homeostasis and contribute to inflammatory responses. Their broad scope of action depends on both functional heterogeneity and plasticity. Small noncoding RNAs called microRNAs (miRNAs) contribute to macrophage function as post-transcriptional inhibitors of target gene networks. Genetic and pharmacologic studies have uncovered genes regulated by miRNAs that control macrophage cellular programming and macrophage-driven pathology. miRNAs control proinflammatory M1-like activation, immunoregulatory M2-like macrophage activation, and emerging macrophage functions in metabolic disease and innate immune memory. Understanding the gene networks regulated by individual miRNAs enhances our understanding of the spectrum of macrophage function at steady state and during responses to injury or pathogen invasion, with the potential to develop miRNA-based therapies. This review aims to consolidate past and current studies investigating the complexity of the miRNA interactome to provide the reader with a mechanistic view of how miRNAs shape macrophage behavior.
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Affiliation(s)
| | - C Henrique Serezani
- Department of Pathology, Microbiology, and Immunology
- Department of Medicine, Division of Infectious Diseases
- Vanderbilt Center for Immunobiology, Nashville, Tennessee 37232, USA
- Vandebilt Institute of Infection, Immunology and Inflammation; Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
| | - Heather H Pua
- Department of Pathology, Microbiology, and Immunology
- Vanderbilt Center for Immunobiology, Nashville, Tennessee 37232, USA
- Vandebilt Institute of Infection, Immunology and Inflammation; Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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6
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Song W, Postoak JL, Yang G, Guo X, Pua HH, Bader J, Rathmell JC, Kobayashi H, Haase VH, Leaptrot KL, Schrimpe-Rutledge AC, Sherrod SD, McLean JA, Zhang J, Wu L, Van Kaer L. Lipid kinase PIK3C3 maintains healthy brown and white adipose tissues to prevent metabolic diseases. Proc Natl Acad Sci U S A 2023; 120:e2214874120. [PMID: 36574710 PMCID: PMC9910429 DOI: 10.1073/pnas.2214874120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/29/2022] [Indexed: 12/28/2022] Open
Abstract
Adequate mass and function of adipose tissues (ATs) play essential roles in preventing metabolic perturbations. The pathological reduction of ATs in lipodystrophy leads to an array of metabolic diseases. Understanding the underlying mechanisms may benefit the development of effective therapies. Several cellular processes, including autophagy and vesicle trafficking, function collectively to maintain AT homeostasis. Here, we investigated the impact of adipocyte-specific deletion of the lipid kinase phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3) on AT homeostasis and systemic metabolism in mice. We report that PIK3C3 functions in all ATs and that its absence disturbs adipocyte autophagy and hinders adipocyte differentiation, survival, and function with differential effects on brown and white ATs. These abnormalities cause loss of white ATs, whitening followed by loss of brown ATs, and impaired "browning" of white ATs. Consequently, mice exhibit compromised thermogenic capacity and develop dyslipidemia, hepatic steatosis, insulin resistance, and type 2 diabetes. While these effects of PIK3C3 largely contrast previous findings with the autophagy-related (ATG) protein ATG7 in adipocytes, mice with a combined deficiency in both factors reveal a dominant role of the PIK3C3-deficient phenotype. We have also found that dietary lipid excess exacerbates AT pathologies caused by PIK3C3 deficiency. Surprisingly, glucose tolerance is spared in adipocyte-specific PIK3C3-deficient mice, a phenotype that is more evident during dietary lipid excess. These findings reveal a crucial yet complex role for PIK3C3 in ATs, with potential therapeutic implications.
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Affiliation(s)
- Wenqiang Song
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
| | - J. Luke Postoak
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
| | - Guan Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Infectious Diseases and Public Health, City University of Hong Kong, Kowloon Tong999077, Hong Kong
| | - Xingyi Guo
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN37232
| | - Heather H. Pua
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
| | - Jackie Bader
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
| | - Jeffrey C. Rathmell
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
| | - Hanako Kobayashi
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN37232
- The Vanderbilt O’Brien Kidney Center, Vanderbilt University Medical Center, Nashville, TN37232
- Medical and Research Services, Department of Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, TN37212
| | - Volker H. Haase
- Division of Nephrology and Hypertension, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN37232
- The Vanderbilt O’Brien Kidney Center, Vanderbilt University Medical Center, Nashville, TN37232
- Medical and Research Services, Department of Veterans Affairs Hospital, Tennessee Valley Healthcare System, Nashville, TN37212
| | - Katrina L. Leaptrot
- Center for Innovative Technology, Vanderbilt University, Nashville, TN37232
- Department of Chemistry, Vanderbilt University, Nashville, TN37232
| | - Alexandra C. Schrimpe-Rutledge
- Center for Innovative Technology, Vanderbilt University, Nashville, TN37232
- Department of Chemistry, Vanderbilt University, Nashville, TN37232
| | - Stacy D. Sherrod
- Center for Innovative Technology, Vanderbilt University, Nashville, TN37232
- Department of Chemistry, Vanderbilt University, Nashville, TN37232
| | - John A. McLean
- Center for Innovative Technology, Vanderbilt University, Nashville, TN37232
- Department of Chemistry, Vanderbilt University, Nashville, TN37232
| | - Jianhua Zhang
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL35294
- Birmingham Veterans Affairs Medical Center, Birmingham, AL35233
| | - Lan Wu
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
| | - Luc Van Kaer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
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7
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Berumen Sánchez G, Bunn KE, Pua HH, Rafat M. Extracellular vesicles: mediators of intercellular communication in tissue injury and disease. Cell Commun Signal 2021; 19:104. [PMID: 34656117 PMCID: PMC8520651 DOI: 10.1186/s12964-021-00787-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/07/2021] [Indexed: 12/13/2022] Open
Abstract
Intercellular communication is a critical process that ensures cooperation between distinct cell types and maintains homeostasis. EVs, which were initially described as cellular debris and devoid of biological function, are now recognized as key components in cell-cell communication. EVs are known to carry multiple factors derived from their cell of origin, including cytokines and chemokines, active enzymes, metabolites, nucleic acids, and surface molecules, that can alter the behavior of recipient cells. Since the cargo of EVs reflects their parental cells, EVs from damaged and dysfunctional tissue environments offer an abundance of information toward elucidating the molecular mechanisms of various diseases and pathological conditions. In this review, we discuss the most recent findings regarding the role of EVs in the progression of cancer, metabolic disorders, and inflammatory lung diseases given the high prevalence of these conditions worldwide and the important role that intercellular communication between immune, parenchymal, and stromal cells plays in the development of these pathological states. We also consider the clinical applications of EVs, including the possibilities for their use as novel therapeutics. While intercellular communication through extracellular vesicles (EVs) is key for physiological processes and tissue homeostasis, injury and stress result in altered communication patterns in the tissue microenvironment. When left unchecked, EV-mediated interactions between stromal, immune, and parenchymal cells lead to the development of disease states Video Abstract.
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Affiliation(s)
- Greg Berumen Sánchez
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN USA
| | - Kaitlyn E. Bunn
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Heather H. Pua
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN USA
| | - Marjan Rafat
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN USA
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN USA
- Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN USA
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8
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Nation GK, Saffold CE, Pua HH. Secret messengers: Extracellular RNA communication in the immune system. Immunol Rev 2021; 304:62-76. [PMID: 34542176 DOI: 10.1111/imr.13027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 08/27/2021] [Accepted: 09/06/2021] [Indexed: 12/11/2022]
Abstract
One of the hallmarks of the immune system is a dynamic landscape of cellular communication through the secretion of soluble factors, production of cell-bound ligands, and expression of surface receptors. This communication affects all aspects of immune cell behavior, integrates the responses of immune cells in tissues, and is fundamental to orchestrating effective immunity. Recent pioneering work has shown that the transfer of ribonucleic acids (RNAs) constitutes a novel mode of cellular communication. This communication involves diverse RNA species, with short noncoding RNAs especially enriched in the extracellular space. These RNAs are highly stable and selectively packaged for secretion. Transferred RNAs have functions in target cells that both mirror their cell-intrinsic roles and adopt novel mechanisms of action. These extracellular RNAs both impact the behavior of individual immune cells and participate in local and systemic immune responses. The impacts of RNA communication on immune cells and disease states have important implications for the development of novel clinical biomarkers and innovative therapeutic designs in immune-related disease. In this review, we will discuss the foundation of knowledge that is establishing RNA communication as an active and functional process in the immune system.
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Affiliation(s)
- Grant K Nation
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Cherie E Saffold
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Heather H Pua
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Vanderbilt Center for Immunobiology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Vandebilt Institute of Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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9
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Pua HH, Happ HC, Gray CJ, Mar DJ, Chiou NT, Hesse LE, Ansel KM. Increased Hematopoietic Extracellular RNAs and Vesicles in the Lung during Allergic Airway Responses. Cell Rep 2020; 26:933-944.e4. [PMID: 30673615 PMCID: PMC6365014 DOI: 10.1016/j.celrep.2019.01.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 10/28/2018] [Accepted: 12/27/2018] [Indexed: 12/30/2022] Open
Abstract
Extracellular RNAs (exRNAs) can be released by numerous cell types in vitro, are often protected within vesicles, and can modify recipient cell function. To determine how the composition and cellular sources of exRNAs and the extracellular vesicles (EVs) that carry them change in vivo during tissue inflammation, we analyzed bronchoalveolar lavage fluid (BALF) from mice before and after lung allergen challenge. In the lung, extracellular microRNAs (ex-miRNAs) had a composition that was highly correlated with airway-lining epithelium. Using cell type-specific membrane tagging and single vesicle flow, we also found that 80% of detected vesicles were of epithelial origin. After the induction of allergic airway inflammation, miRNAs selectively expressed by immune cells, including miR-223 and miR-142a, increased and hematopoietic-cell-derived EVs also increased >2-fold. These data demonstrate that infiltrating immune cells release ex-miRNAs and EVs in inflamed tissues to alter the local extracellular environment.
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Affiliation(s)
- Heather H Pua
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143, USA; Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Hannah C Happ
- Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Carleigh J Gray
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Darryl J Mar
- Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ni-Ting Chiou
- Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Laura E Hesse
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - K Mark Ansel
- Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA.
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10
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Fassett MS, Pua HH, Simpson LJ, Steiner DF, Ansel KM. Identification of Functionally Relevant microRNAs in the Regulation of Allergic Inflammation. Methods Mol Biol 2019; 1799:341-351. [PMID: 29956162 DOI: 10.1007/978-1-4939-7896-0_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Transgenic methods to manipulate CD4 T lymphocytes in vivo via forced expression of TCR transgenes and targeted "knockout" of individual genes by Cre-lox technology are fundamental to modern immunology. However, efforts to scale up functional analysis by modifying expression of larger numbers of genes in T cells ex vivo have proven surprisingly difficult. Early RNA interference experiments achieved successful small RNA transfection by using very high concentrations of short-interfering RNA (siRNA) [1], but primary T cells are generally resistant to standard electroporation, cationic liposome-, and calcium phosphate-mediated transfection methods. Moreover, although viral vectors can successfully introduce DNA fragments of varying length, expression of these constructs in primary T cells is low efficiency and the subcloning process laborious. In this context, the relatively recent discovery of dozens of highly expressed microRNAs (miRNAs) in the immune system provides both an opportunity and a new challenge [2, 3]. How can we query the miRNAome of a cell to assign particular roles to individual miRNAs? Here, we describe an optimized technique for efficient and reproducible transfection of primary mouse CD4 T cells in vitro with synthetic miRNA mimics.
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Affiliation(s)
- Marlys S Fassett
- Sandler Asthma Basic Research Center, Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.,Department of Dermatology, University of California, San Francisco, CA, USA
| | - Heather H Pua
- Sandler Asthma Basic Research Center, Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.,Department of Pathology, University of California, San Francisco, CA, USA
| | - Laura J Simpson
- Sandler Asthma Basic Research Center, Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - David F Steiner
- Sandler Asthma Basic Research Center, Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - K Mark Ansel
- Sandler Asthma Basic Research Center, Department of Microbiology and Immunology, University of California, San Francisco, CA, USA.
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11
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Singh PB, Pua HH, Happ HC, Schneider C, von Moltke J, Locksley RM, Baumjohann D, Ansel KM. MicroRNA regulation of type 2 innate lymphoid cell homeostasis and function in allergic inflammation. J Exp Med 2017; 214:3627-3643. [PMID: 29122948 PMCID: PMC5716040 DOI: 10.1084/jem.20170545] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 07/05/2017] [Accepted: 09/21/2017] [Indexed: 12/30/2022] Open
Abstract
Singh et al. examined microRNA expression and physiological requirements in type 2 innate lymphoid cells (ILC2s). The miR-17∼92 cluster promotes ILC2 growth, cytokine expression, and function in allergic inflammation. MicroRNAs (miRNAs) exert powerful effects on immunity through coordinate regulation of multiple target genes in a wide variety of cells. Type 2 innate lymphoid cells (ILC2s) are tissue sentinel mediators of allergic inflammation. We established the physiological requirements for miRNAs in ILC2 homeostasis and immune function and compared the global miRNA repertoire of resting and activated ILC2s and T helper type 2 (TH2) cells. After exposure to the natural allergen papain, mice selectively lacking the miR-17∼92 cluster in ILC2s displayed reduced lung inflammation. Moreover, miR-17∼92–deficient ILC2s exhibited defective growth and cytokine expression in response to IL-33 and thymic stromal lymphopoietin in vitro. The miR-17∼92 cluster member miR-19a promoted IL-13 and IL-5 production and inhibited expression of several targets, including SOCS1 and A20, signaling inhibitors that limit IL-13 and IL-5 production. These findings establish miRNAs as important regulators of ILC2 biology, reveal overlapping but nonidentical miRNA-regulated gene expression networks in ILC2s and TH2 cells, and reinforce the therapeutic potential of targeting miR-19 to alleviate pathogenic allergic responses.
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Affiliation(s)
- Priti B Singh
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA.,Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA
| | - Heather H Pua
- Department of Pathology, University of California, San Francisco, San Francisco, CA.,Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA
| | - Hannah C Happ
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA.,Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA
| | - Christoph Schneider
- Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Jakob von Moltke
- Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Richard M Locksley
- Department of Medicine, University of California, San Francisco, San Francisco, CA.,Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA.,Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA
| | - Dirk Baumjohann
- Institute for Immunology, Biomedical Center Munich, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany
| | - K Mark Ansel
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA .,Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA
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12
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Montoya MM, Maul J, Singh PB, Pua HH, Dahlström F, Wu N, Huang X, Ansel KM, Baumjohann D. A Distinct Inhibitory Function for miR-18a in Th17 Cell Differentiation. J Immunol 2017; 199:559-569. [PMID: 28607111 DOI: 10.4049/jimmunol.1700170] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/17/2017] [Indexed: 02/01/2023]
Abstract
Th17 cell responses orchestrate immunity against extracellular pathogens but also underlie autoimmune disease pathogenesis. In this study, we uncovered a distinct and critical role for miR-18a in limiting Th17 cell differentiation. miR-18a was the most dynamically upregulated microRNA of the miR-17-92 cluster in activated T cells. miR-18a deficiency enhanced CCR6+ RAR-related orphan receptor (ROR)γt+ Th17 cell differentiation in vitro and increased the number of tissue Th17 cells expressing CCR6, RORγt, and IL-17A in airway inflammation models in vivo. Sequence-specific miR-18 inhibitors increased CCR6 and RORγt expression in mouse and human CD4+ T cells, revealing functional conservation. miR-18a directly targeted Smad4, Hif1a, and Rora, all key transcription factors in the Th17 cell gene-expression program. These findings indicate that activating signals influence the outcome of Th cell differentiation via differential regulation of mature microRNAs within a common cluster.
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Affiliation(s)
- Misty M Montoya
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143
| | - Julia Maul
- Institute for Immunology, Biomedical Center Munich, Ludwig Maximilians University, 82152 Planegg-Martinsried, Germany
| | - Priti B Singh
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143
| | - Heather H Pua
- Department of Pathology, University of California, San Francisco, San Francisco, CA 94143; and
| | - Frank Dahlström
- Institute for Immunology, Biomedical Center Munich, Ludwig Maximilians University, 82152 Planegg-Martinsried, Germany
| | - Nanyan Wu
- Lung Biology Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143
| | - Xiaozhu Huang
- Lung Biology Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143
| | - K Mark Ansel
- Department of Microbiology and Immunology, Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, CA 94143;
| | - Dirk Baumjohann
- Institute for Immunology, Biomedical Center Munich, Ludwig Maximilians University, 82152 Planegg-Martinsried, Germany;
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13
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Pua HH, Steiner DF, Patel S, Gonzalez JR, Ortiz-Carpena JF, Kageyama R, Chiou NT, Gallman A, de Kouchkovsky D, Jeker LT, McManus MT, Erle DJ, Ansel KM. MicroRNAs 24 and 27 Suppress Allergic Inflammation and Target a Network of Regulators of T Helper 2 Cell-Associated Cytokine Production. Immunity 2016; 44:821-32. [PMID: 26850657 DOI: 10.1016/j.immuni.2016.01.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 11/17/2015] [Accepted: 01/06/2016] [Indexed: 01/02/2023]
Abstract
MicroRNAs (miRNAs) are important regulators of cell fate decisions in immune responses. They act by coordinate repression of multiple target genes, a property that we exploited to uncover regulatory networks that govern T helper-2 (Th2) cells. A functional screen of individual miRNAs in primary T cells uncovered multiple miRNAs that inhibited Th2 cell differentiation. Among these were miR-24 and miR-27, miRNAs coexpressed from two genomic clusters, which each functioned independently to limit interleukin-4 (IL-4) production. Mice lacking both clusters in T cells displayed increased Th2 cell responses and tissue pathology in a mouse model of asthma. Gene expression and pathway analyses placed miR-27 upstream of genes known to regulate Th2 cells. They also identified targets not previously associated with Th2 cell biology which regulated IL-4 production in unbiased functional testing. Thus, elucidating the biological function and target repertoire of miR-24 and miR-27 reveals regulators of Th2 cell biology.
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Affiliation(s)
- Heather H Pua
- Department of Pathology, University of California, San Francisco, San Francisco, CA, USA
| | - David F Steiner
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Sana Patel
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Jeanmarie R Gonzalez
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Jorge F Ortiz-Carpena
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Robin Kageyama
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Ni-Ting Chiou
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Antonia Gallman
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | | | - Lukas T Jeker
- Department of Pathology, University of California, San Francisco, San Francisco, CA, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA, USA
| | - Michael T McManus
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA; Diabetes Center, University of California, San Francisco, San Francisco, CA, USA
| | - David J Erle
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - K Mark Ansel
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA; Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco CA, USA.
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14
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Pua HH, Ansel KM. MicroRNA regulation of allergic inflammation and asthma. Curr Opin Immunol 2015; 36:101-8. [PMID: 26253882 DOI: 10.1016/j.coi.2015.07.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 07/13/2015] [Accepted: 07/17/2015] [Indexed: 12/18/2022]
Abstract
Allergic diseases are prevalent and clinically heterogeneous, and are the pathologic consequence of inappropriate or exaggerated type 2 immune responses. In this review, we explore the role of microRNAs (miRNAs) in regulating allergic inflammation. We discuss how miRNAs, acting through target genes to modulate gene expression networks, impact multiple facets of immune cell function critical for type 2 immune responses including cell survival, proliferation, differentiation, and effector functions. Human and mouse studies indicate that miRNAs are significant regulators of allergic immune responses. Finally, investigations of extracellular miRNAs offer promise for noninvasive biomarkers and therapeutic strategies for allergy and asthma.
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Affiliation(s)
- Heather H Pua
- Department of Pathology, San Francisco, CA, United States; Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA, United States
| | - K Mark Ansel
- Department of Microbiology and Immunology, San Francisco, CA, United States; Sandler Asthma Basic Research Center, University of California San Francisco, San Francisco, CA, United States.
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15
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Pua HH, Krishnamurthi S, Farrell J, Margeta M, Ursell PC, Powers M, Slavotinek AM, Jeng LJB. Novel interstitial 2.6 Mb deletion on 9q21 associated with multiple congenital anomalies. Am J Med Genet A 2015; 164A:237-42. [PMID: 24501764 DOI: 10.1002/ajmg.a.36230] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Array comparative genomic hybridization (aCGH) is now commonly used to identify copy number changes in individuals with developmental delay, intellectual disabilities, autism spectrum disorders, and/or multiple congenital anomalies. We report on an infant with multiple congenital anomalies and a novel 2.6 Mb interstitial deletion within 9q21.32q21.33 detected by aCGH. Her clinical presentation included dysmorphic craniofacial features, cleft palate, atrial septal defect, bicornuate uterus, bilateral hip dislocation, hypotonia, and recurrent pneumonia. Parental aCGH studies were negative for copy loss in this region. To our knowledge, no similar deletions have been reported in available databases or published literature. This deletion encompasses 12 genes, and prediction algorithms as well as experimental data suggest that a subset is likely to be haploinsufficient. Included are a neurotrophin receptor (NKG2D), a gene implicated in cilia function (KIF27), an adaptor protein important for ubiquitin-dependent protein quality control (UBQLN1), a gene important for transcription and signaling (HNRNPK), and a gene involved in maintaining genomic stability (RMI1). Identifying additional patients with similar copy losses and further study of these genes will contribute to a better understanding of the pathophysiology of multiple congenital anomalies.
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16
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Jia W, Pua HH, Li QJ, He YW. Autophagy regulates endoplasmic reticulum homeostasis and calcium mobilization in T lymphocytes. J Immunol 2010; 186:1564-74. [PMID: 21191072 DOI: 10.4049/jimmunol.1001822] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved intracellular bulk degradation pathway that plays critical roles in eliminating intracellular pathogens, presenting endogenous Ags, and regulating T lymphocyte survival and proliferation. In this study, we have investigated the role of autophagy in regulating the endoplasmic reticulum (ER) compartment in T lymphocytes. We found that ER content is expanded in mature autophagy-related protein (Atg) 7-deficient T lymphocytes. Atg7-deficient T cells stimulated through the TCR display impaired influx, but not efflux, of calcium, and ER calcium stores are increased in Atg7-deficient T cells. Treatment with the ER sarco/ER Ca(2+)-ATPase pump inhibitor thapsigargin rescues the calcium influx defect in Atg7-deficient T lymphocytes, suggesting that this impairment is caused by an intrinsic defect in ER. Furthermore, we found that the stimulation-induced redistribution of stromal interaction molecule-1, a critical event for the store-operated Ca(2+) release-activated Ca(2+) channel opening, is impaired in Atg7-deficient T cells. Together, these findings indicate that the expanded ER compartment in Atg7-deficient T cells contains increased calcium stores, and the inability of these stores to be depleted causes defective calcium influx in these cells. Our results demonstrate that autophagy plays an important role in maintaining ER and calcium homeostasis in T lymphocytes.
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Affiliation(s)
- Wei Jia
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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17
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Affiliation(s)
- Heather H Pua
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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18
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Abstract
Macroautophagy plays an important role in the regulation of cell survival, metabolism, and the lysosomal degradation of cytoplasmic material. In the immune system, autophagy contributes to the clearance of intracellular pathogens, MHCII cross-presentation of endogenous Ags, as well as cell survival. We and others have demonstrated that autophagy occurs in T lymphocytes and contributes to the regulation of their cellular function, including survival and proliferation. Here we show that the essential autophagy gene Atg7 is required in a cell-intrinsic manner for the survival of mature primary T lymphocytes. We also find that mitochondrial content is developmentally regulated in T but not in B cells, with exit from the thymus marking a transition from high mitochondrial content in thymocytes to lower mitochondrial content in mature T cells. Macroautophagy has been proposed to play an important role in the clearance of intracellular organelles, and autophagy-deficient mature T cells fail to reduce their mitochondrial content in vivo. Consistent with alterations in mitochondrial content, autophagy-deficient T cells have increased reactive oxygen species production as well as an imbalance in pro- and antiapoptotic protein expression. With much recent interest in the possibility of autophagy-dependent developmentally programmed clearance of organelles in lens epithelial cells and erythrocytes, our data demonstrate that autophagy may have a physiologically significant role in the clearance of superfluous mitochondria in T lymphocytes as part of normal T cell homeostasis.
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Affiliation(s)
- Heather H Pua
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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19
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Miller BC, Zhao Z, Stephenson LM, Cadwell K, Pua HH, Lee HK, Mizushima NN, Iwasaki A, He YW, Swat W, Virgin HW. The autophagy gene ATG5 plays an essential role in B lymphocyte development. Autophagy 2007; 4:309-14. [PMID: 18188005 DOI: 10.4161/auto.5474] [Citation(s) in RCA: 276] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Macroautophagy (herein autophagy) is an evolutionarily conserved process, requiring the gene ATG5, by which cells degrade cytoplasmic constituents and organelles. Here we show that ATG5 is required for efficient B cell development and for the maintenance of B-1a B cell numbers. Deletion of ATG5 in B lymphocytes using Cre-LoxP technology or repopulation of irradiated mice with ATG5-/- fetal liver progenitors resulted in a dramatic reduction in B-1 B cells in the peritoneum. ATG5-/- progenitors exhibited a significant defect in B cell development at the pro- to pre-B cell transition, although a proportion of pre-B cells survived to populate the periphery. Inefficient B cell development in the bone marrow was associated with increased cell death, indicating that ATG5 is important for B cell survival during development. In addition, B-1a B cells require ATG5 for their maintenance in the periphery. We conclude that ATG5 is differentially required at discrete stages of development in distinct, but closely related, cell lineages.
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Affiliation(s)
- Brian C Miller
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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20
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Abstract
First identified as a pathway for nutrient recovery during periods of starvation, the role of autophagy has expanded to the clearance of "toxic" intracellular material including ubiquitin-positive protein aggregates, damaged organelles as well as microbial pathogens in various cell types. We have examined the role of autophagy in the development and function of the adaptive immune system. Genes encoding autophagy machinery are expressed in T lymphocytes, and autophagy occurs in primary CD4+ and CD8+ T cells. By generating fetal liver chimeric mice, we found that thymocyte development is largely normal but the mature T cell compartment is severely reduced in the absence of the essential autophagy gene Atg5. Consistent with a critical role for autophagy in promoting T cell survival, Atg5-/- CD8+ T cells display high levels of apoptosis. Surprisingly, Atg5-deficient T cells were also unable to efficiently proliferate after T-cell receptor (TCR) stimulation. These findings suggest that autophagy regulates T lymphocyte homeostasis by promoting both survival and proliferation. In addition, T cells offer a new, physiologically relevant system to study the regulation and function of autophagy pathways in vivo.
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Affiliation(s)
- Heather H Pua
- Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA
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21
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Pua HH, Dzhagalov I, Chuck M, Mizushima N, He YW. A critical role for the autophagy gene Atg5 in T cell survival and proliferation. J Biophys Biochem Cytol 2007. [DOI: 10.1083/jcb1761oia5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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22
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Abstract
Macroautophagy (hereafter referred to as autophagy) is a well-conserved intracellular degradation process. Recent studies examining cells lacking the autophagy genes Atg5 and Atg7 have demonstrated that autophagy plays essential roles in cell survival during starvation, in innate cell clearance of microbial pathogens, and in neural cell maintenance. However, the role of autophagy in T lymphocyte development and survival is not known. Here, we demonstrate that autophagosomes form in primary mouse T lymphocytes. By generating Atg5−/− chimeric mice, we found that Atg5-deficient T lymphocytes underwent full maturation. However, the numbers of total thymocytes and peripheral T and B lymphocytes were reduced in Atg5 chimeras. In the periphery, Atg5−/− CD8+ T lymphocytes displayed dramatically increased cell death. Furthermore, Atg5−/− CD4+ and CD8+ T cells failed to undergo efficient proliferation after TCR stimulation. These results demonstrate a critical role for Atg5 in multiple aspects of lymphocyte development and function and suggest that autophagy may be essential for both T lymphocyte survival and proliferation.
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Affiliation(s)
- Heather H Pua
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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