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Swann JW, Olson OC, Passegué E. Made to order: emergency myelopoiesis and demand-adapted innate immune cell production. Nat Rev Immunol 2024:10.1038/s41577-024-00998-7. [PMID: 38467802 DOI: 10.1038/s41577-024-00998-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2024] [Indexed: 03/13/2024]
Abstract
Definitive haematopoiesis is the process by which haematopoietic stem cells, located in the bone marrow, generate all haematopoietic cell lineages in healthy adults. Although highly regulated to maintain a stable output of blood cells in health, the haematopoietic system is capable of extensive remodelling in response to external challenges, prioritizing the production of certain cell types at the expense of others. In this Review, we consider how acute insults, such as infections and cytotoxic drug-induced myeloablation, cause molecular, cellular and metabolic changes in haematopoietic stem and progenitor cells at multiple levels of the haematopoietic hierarchy to drive accelerated production of the mature myeloid cells needed to resolve the initiating insult. Moreover, we discuss how dysregulation or subversion of these emergency myelopoiesis mechanisms contributes to the progression of chronic inflammatory diseases and cancer.
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Affiliation(s)
- James W Swann
- Columbia Stem Cell Initiative, Department of Genetics and Development, Columbia University, New York, NY, USA
| | - Oakley C Olson
- Columbia Stem Cell Initiative, Department of Genetics and Development, Columbia University, New York, NY, USA
| | - Emmanuelle Passegué
- Columbia Stem Cell Initiative, Department of Genetics and Development, Columbia University, New York, NY, USA.
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2
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Shim J, Park S, Venkateswaran S, Kumar D, Prince C, Parihar V, Maples L, Waller EK, Kugathasan S, Briones M, Lee M, Henry CJ, Prahalad S, Chandrakasan S. Early B-cell development and B-cell maturation are impaired in patients with active hemophagocytic lymphohistiocytosis. Blood 2023; 142:1972-1984. [PMID: 37624902 PMCID: PMC10731577 DOI: 10.1182/blood.2023020426] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Hemophagocytic lymphohistiocytosis (HLH) is characterized by hyperinflammation and multiorgan dysfunction. Infections, including the reactivation of viruses, contribute to significant disease mortality in HLH. Although T-cell and natural killer cell-driven immune activation and dysregulation are well described, limited data exist on the status of B-cell compartment and humoral immune function in HLH. We noted marked suppression of early B-cell development in patients with active HLH. In vitro B-cell differentiation studies after exposure to HLH-defining cytokines, such as interferon gamma (IFN-γ) and tumor necrosis factor, recapitulated B-cell development arrest. Messenger RNA sequencing of human CD34+ cells exposed to IFN-γ demonstrated changes in genes and pathways affecting B-cell development and maturation. In addition, patients with active HLH exhibited a marked decrease in class-switched memory B (CSMB) cells and a decrease in bone marrow plasmablast/plasma cell compartments. The decrease in CSMB cells was associated with a decrease in circulating T follicular helper (cTfh) cells. Finally, lymph node and spleen evaluation in a patient with HLH revealed absent germinal center formation and hemophagocytosis with associated lymphopenia. Reassuringly, the frequency of CSMB and cTfh improved with the control of T-cell activation. Taken together, in patients with active HLH, these changes in B cells may affect the humoral immune response; however, further immune studies are needed to determine its clinical significance.
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Affiliation(s)
- Jenny Shim
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Sunita Park
- Department of Pathology, Children’s Healthcare of Atlanta, Atlanta, GA
| | - Suresh Venkateswaran
- Division of Pediatric Gastroenterology, Department of Pediatrics, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Deepak Kumar
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Chengyu Prince
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Vaunita Parihar
- Cancer Tissue and Pathology Shared Resource Core, Emory University School of Medicine, Atlanta, GA
| | - Larkin Maples
- Department of Pathology, Children’s Healthcare of Atlanta, Atlanta, GA
| | - Edmund K. Waller
- Department of Hematology and Medical Oncology, Winship Cancer Institute, Emory University, Atlanta, GA
| | - Subra Kugathasan
- Division of Pediatric Gastroenterology, Department of Pediatrics, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Michael Briones
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Miyoung Lee
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Curtis J. Henry
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Sampath Prahalad
- Division of Pediatric Rheumatology, Department of Pediatrics, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
| | - Shanmuganathan Chandrakasan
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children’s Healthcare of Atlanta, Emory University School of Medicine, Atlanta, GA
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3
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Barman PK, Goodridge HS. Microbial Sensing by Hematopoietic Stem and Progenitor Cells. Stem Cells 2022; 40:14-21. [PMID: 35511863 PMCID: PMC9072977 DOI: 10.1093/stmcls/sxab007] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 09/09/2021] [Indexed: 01/21/2023]
Abstract
Balanced production of immune cells is critical for the maintenance of steady-state immune surveillance, and increased production of myeloid cells is sometimes necessary to eliminate pathogens. Hematopoietic stem and progenitor cell (HSPC) sensing of commensal microbes and invading pathogens has a notable impact on hematopoiesis. In this review, we examine how commensal microbes regulate bone marrow HSPC activity to maintain balanced hematopoiesis in the steady state, and how HSPCs proliferate and differentiate during emergency myelopoiesis in response to infection. HSPCs express a variety of pattern recognition receptors and cytokine receptors that they use to sense the presence of microbes, either directly via detection of microbial components and metabolites, or indirectly by responding to cytokines produced by other host cells. We describe direct and indirect mechanisms of microbial sensing by HSPCs and highlight evidence demonstrating long-term effects of acute and chronic microbial stimuli on HSPCs. We also discuss a possible connection between myeloid-biased hematopoiesis and elevated levels of circulating microbiome-derived components in the context of aging and metabolic stress. Finally, we highlight the prospect of trained immunity-based vaccines that could exploit microbial stimulation of HSPCs.
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Affiliation(s)
- Pijus K Barman
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Helen S Goodridge
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Corresponding author: Helen S. Goodridge, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.
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4
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Bassani B, Tripodo C, Portararo P, Gulino A, Botti L, Chiodoni C, Jachetti E, Bolli N, Ciciarello M, Joehrens K, Anagnostopoulos I, Na IK, Curti A, Colombo MP, Sangaletti S. CD40 Activity on Mesenchymal Cells Negatively Regulates OX40L to Maintain Bone Marrow Immune Homeostasis Under Stress Conditions. Front Immunol 2021; 12:662048. [PMID: 34084166 PMCID: PMC8168593 DOI: 10.3389/fimmu.2021.662048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/26/2021] [Indexed: 12/24/2022] Open
Abstract
Background Within the bone marrow (BM), mature T cells are maintained under homeostatic conditions to facilitate proper hematopoietic development. This homeostasis depends upon a peculiar elevated frequency of regulatory T cells (Tregs) and immune regulatory activities from BM-mesenchymal stem cells (BM-MSCs). In response to BM transplantation (BMT), the conditioning regimen exposes the BM to a dramatic induction of inflammatory cytokines and causes an unbalanced T-effector (Teff) and Treg ratio. This imbalance negatively impacts hematopoiesis, particularly in regard to B-cell lymphopoiesis that requires an intact cross-talk between BM-MSCs and Tregs. The mechanisms underlying the ability of BM-MSCs to restore Treg homeostasis and proper B-cell development are currently unknown. Methods We studied the role of host radio-resistant cell-derived CD40 in restoring Teff/Treg homeostasis and proper B-cell development in a murine model of BMT. We characterized the host cellular source of CD40 and performed radiation chimera analyses by transplanting WT or Cd40-KO with WT BM in the presence of T-reg and co-infusing WT or - Cd40-KO BM-MSCs. Residual host and donor T cell expansion and activation (cytokine production) and also the expression of Treg fitness markers and conversion to Th17 were analyzed. The presence of Cd40+ BM-MSCs was analyzed in a human setting in correlation with the frequency of B-cell precursors in patients who underwent HSCT and variably developed acute graft-versus-host (aGVDH) disease. Results CD40 expression is nearly undetectable in the BM, yet a Cd40-KO recipient of WT donor chimera exhibited impaired B-cell lymphopoiesis and Treg development. Lethal irradiation promotes CD40 and OX40L expression in radio-resistant BM-MSCs through the induction of pro-inflammatory cytokines. OX40L favors Teff expansion and activation at the expense of Tregs; however, the expression of CD40 dampens OX40L expression and restores Treg homeostasis, thus facilitating proper B-cell development. Indeed, in contrast to dendritic cells in secondary lymphoid organs that require CD40 triggers to express OX40L, BM-MSCs require CD40 to inhibit OX40L expression. Conclusions CD40+ BM-MSCs are immune regulatory elements within BM. Loss of CD40 results in uncontrolled T cell activation due to a reduced number of Tregs, and B-cell development is consequently impaired. GVHD provides an example of how a loss of CD40+ BM-MSCs and a reduction in B-cell precursors may occur in a human setting.
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Affiliation(s)
- Barbara Bassani
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | | | - Paola Portararo
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | | | - Laura Botti
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Claudia Chiodoni
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Elena Jachetti
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Niccolò Bolli
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy.,Hematology, Fondazione Cà Granda IRCCS Policlinico, Milan, Italy
| | - Marilena Ciciarello
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Institute of Hematology "Seràgnoli", Bologna, Italy
| | - Korinna Joehrens
- Charité-Universitätsmedizin Berlin, Institute of Pathology, Berlin, Germany
| | | | - Il-Kang Na
- Department of Hematology, Oncology and Tumor Immunology, Charité-Universitätsmedizin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany.,Experimental and Clinical Research Center (ECRC), Berlin, Germany
| | - Antonio Curti
- Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Institute of Hematology "Seràgnoli", Bologna, Italy
| | - Mario P Colombo
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Sabina Sangaletti
- Department of Research, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
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5
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Zhang L, Mack R, Breslin P, Zhang J. Molecular and cellular mechanisms of aging in hematopoietic stem cells and their niches. J Hematol Oncol 2020; 13:157. [PMID: 33228751 PMCID: PMC7686726 DOI: 10.1186/s13045-020-00994-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 11/09/2020] [Indexed: 02/08/2023] Open
Abstract
Aging drives the genetic and epigenetic changes that result in a decline in hematopoietic stem cell (HSC) functioning. Such changes lead to aging-related hematopoietic/immune impairments and hematopoietic disorders. Understanding how such changes are initiated and how they progress will help in the development of medications that could improve the quality life for the elderly and to treat and possibly prevent aging-related hematopoietic diseases. Here, we review the most recent advances in research into HSC aging and discuss the role of HSC-intrinsic events, as well as those that relate to the aging bone marrow niche microenvironment in the overall processes of HSC aging. In addition, we discuss the potential mechanisms by which HSC aging is regulated.
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Affiliation(s)
- Lei Zhang
- Department of Cancer Biology, Oncology Institute, Cardinal Bernardin Cancer Center, Loyola University Medical Center, Maywood, IL, 60153, USA
| | - Ryan Mack
- Department of Cancer Biology, Oncology Institute, Cardinal Bernardin Cancer Center, Loyola University Medical Center, Maywood, IL, 60153, USA
| | - Peter Breslin
- Department of Cancer Biology, Oncology Institute, Cardinal Bernardin Cancer Center, Loyola University Medical Center, Maywood, IL, 60153, USA.,Departments of Molecular/Cellular Physiology and Department of Biology, Loyola University Medical Center and Loyola University Chicago, Chicago, IL, 60660, USA
| | - Jiwang Zhang
- Department of Cancer Biology, Oncology Institute, Cardinal Bernardin Cancer Center, Loyola University Medical Center, Maywood, IL, 60153, USA. .,Department of Pathology, Loyola University Medical Center, Maywood, IL, 60153, USA.
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6
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Sioud M. Microbial sensing by haematopoietic stem and progenitor cells: Vigilance against infections and immune education of myeloid cells. Scand J Immunol 2020; 92:e12957. [PMID: 32767789 DOI: 10.1111/sji.12957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/17/2020] [Accepted: 08/04/2020] [Indexed: 12/12/2022]
Abstract
Bone marrow haematopoietic stem and progenitor cells (HSPCs) express pattern recognition receptors such as Toll-like receptors (TLRs) to sense microbial products and activation of these innate immune receptors induces cytokine expression and redirects bone marrow haematopoiesis towards the increased production of myeloid cells. Secreted cytokines by HSPCs in response to TLR ligands can act in an autocrine or paracrine manner to regulate haematopoiesis. Moreover, tonic activation of HSPCs by microbiota-derived compounds might educate HSPCs to produce superior myeloid cells equipped with innate memory responses to combat pathogens. While haematopoietic stem cell activation through TLRs meets the increased demand for blood leucocytes to protect the host against infection, persistent exposure to inflammatory cytokines or microbial products might impair their function and even induce malignant transformation. This review highlights the potential outcomes of HSPCs in response to TLR ligands.
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Affiliation(s)
- Mouldy Sioud
- Department of Cancer Immunology, Oslo University Hospital-Radiumhospitalet, Montebello, Norway
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7
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Qin Y, Fang K, Lu N, Hu Y, Tian Z, Zhang C. Interferon gamma inhibits the differentiation of mouse adult liver and bone marrow hematopoietic stem cells by inhibiting the activation of notch signaling. Stem Cell Res Ther 2019; 10:210. [PMID: 31311586 PMCID: PMC6636148 DOI: 10.1186/s13287-019-1311-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/18/2019] [Accepted: 06/20/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The paradigm of hematopoietic stem and progenitor cells (HSPCs) has become accepted ever since the discovery of adult mouse liver hematopoietic stem cells and their multipotent characteristics that give rise to all blood cells. However, differences between bone marrow (BM) and liver hematopoietic stem cells and the hematopoietic microenvironment remain poorly understood. In addition, the regulation of the liver hematopoietic system remains unknown. METHODS Clone formation assays were used to confirm that the proliferation of adult mouse liver and bone marrow HSPCs. Model mice with different interferon gamma (IFN-γ) levels and a co-culture system were used to detect the differentiation of liver HSPCs. The γ-secretase inhibitor (GSI) and the JAK/STAT inhibitor ruxolitinib and cell culture assays were used to explore the molecular mechanism by which IFN-γ impairs HSPC proliferation and differentiation. RESULTS The colony-forming activity of liver and bone marrow HSPCs was inhibited by IFN-γ. Model mice with different IFN-γ levels showed that the differentiation of liver HSPCs was impaired by IFN-γ. Using a co-culture system comprising liver HSPCs, we found that IFN-γ inhibited the development of liver hematopoietic stem cells into γδT cells. We then demonstrated that IFN-γ might impair liver HSPC differentiation by inhibiting the activation of the notch signaling via the JAK/STAT signaling pathway. CONCLUSIONS IFN-γ inhibited the proliferation of liver-derived HSPCs. IFN-γ also impaired the differentiation of long-term hematopoietic stem cells (LT-HSCs) into short-term hematopoietic stem cells (ST-HSCs) and multipotent progenitors (MPPs) and the process from LSK (Lineage-Sca-1+c-Kit+) cells to γδT cells. Importantly, we proposed that IFN-γ might inhibit the activation of notch signaling through the JAK/STAT signaling pathway and thus impair the differentiation process of mouse adult liver and BM hematopoietic stem cells.
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Affiliation(s)
- Yuhong Qin
- Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, Shandong, China
| | - Keke Fang
- Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, Shandong, China
| | - Nan Lu
- Institute of Diagnostics, School of Medicine, Shandong University, Jinan, 250012, Shandong, China.
| | - Yuan Hu
- Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, Shandong, China
| | - Zhigang Tian
- Institute of Immunology, School of Life Sciences, University of Science and Technology of China, Hefei, 230026, Anhui, China
| | - Cai Zhang
- Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, Jinan, 250012, Shandong, China.
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8
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Pioli PD, Casero D, Montecino-Rodriguez E, Morrison SL, Dorshkind K. Plasma Cells Are Obligate Effectors of Enhanced Myelopoiesis in Aging Bone Marrow. Immunity 2019; 51:351-366.e6. [PMID: 31303400 DOI: 10.1016/j.immuni.2019.06.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 04/10/2019] [Accepted: 06/12/2019] [Indexed: 12/25/2022]
Abstract
Aging results in increased myelopoiesis, which is linked to the increased incidence of myeloid leukemias and production of myeloid-derived suppressor cells. Here, we examined the contribution of plasma cells (PCs) to age-related increases in myelopoiesis, as PCs exhibit immune regulatory function and sequester in bone marrow (BM). PC number was increased in old BM, and they exhibited high expression of genes encoding inflammatory cytokines and pathogen sensors. Antibody-mediated depletion of PCs from old mice reduced the number of myeloid-biased hematopoietic stem cells and mature myeloid cells to levels in young animals, but lymphopoiesis was not rejuvenated, indicating that redundant mechanisms inhibit that process. PCs also regulated the production of inflammatory factors from BM stromal cells, and disruption of the PC-stromal cell circuitry with inhibitors of the cytokines IL-1 and TNF-α attenuated myelopoiesis in old mice. Thus, the age-related increase in myelopoiesis is driven by an inflammatory network orchestrated by PCs.
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Affiliation(s)
- Peter D Pioli
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - David Casero
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | | | - Sherie L Morrison
- Department of Microbiology, Immunology and Molecular Genetics, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Kenneth Dorshkind
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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9
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The Regulatory Role of IFN-γ on the Proliferation and Differentiation of Hematopoietic Stem and Progenitor Cells. Stem Cell Rev Rep 2018; 13:705-712. [PMID: 28852997 DOI: 10.1007/s12015-017-9761-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The replenishment of all blood cell lineages is hierarchically organized by the process of hematopoiesis, which is based on the differentiation pathways of hematopoietic stem and progenitor cells (HSPCs). Due to the ability to balance between self-renewal and differentiation, hematopoietic stem cells (HSCs) can generate the appropriate cell type that is required by the immune system and peripheral blood in response to physiological or pathological conditions. Numerous studies have shown that some proinflammatory cytokines contribute to the regulation of the various hematopoietic compartments. Of these, IFN-γ is a type II interferon primarily produced by T cells and natural killer cells, and plays a major role in the defense against invading pathogens and transformed cancer cells; moreover, a growing amount of research indicates that it exerts negative or positive regulatory effect on hematopoiesis. Although IFN-γ is a widely regarded negative regulator of HSC proliferation, it also participates in some chronic infections or hematological malignancies that induce bone marrow failure. Recent studies have demonstrated unexpected effects of IFN-γ, including the promotion of HSC formation and the stimulation of myelopoiesis. Here, we review the direct and indirect effects of IFN-γ on hematopoiesis, as well as the underlying signaling mechanisms of how IFN-γ modulates the self-renewal, cell cycle entry, and proliferation of HSCs. Next, we describe how IFN-γ affects different stages of the lineage differentiation from HSCs. Finally, we discuss the relationship between IFN-γ and compensatory extramedullary hematopoiesis, as well as some related clinical diseases.
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10
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TLR9-mediated inflammation drives a Ccr2-independent peripheral monocytosis through enhanced extramedullary monocytopoiesis. Proc Natl Acad Sci U S A 2016; 113:10944-9. [PMID: 27621476 DOI: 10.1073/pnas.1524487113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Monocytes are innate immune cells that interact with their environment through the expression of pattern recognition receptors, including Toll-like receptors (TLRs). Both monocytes and TLRs are implicated in driving persistent inflammation in autoimmune diseases. However, cell-intrinsic mechanisms to control inflammation, including TLR tolerance, are thought to limit inflammatory responses in the face of repeated TLR activation, leaving it unclear how chronic TLR-mediated inflammation is maintained in vivo. Herein, we used a well-characterized model of systemic inflammation to determine the mechanisms allowing sustained TLR9 responses to develop in vivo. Monocytes were identified as the main TLR9-responsive cell and accumulated in peripherally inflamed tissues during TLR9-driven inflammation. Intriguingly, canonical mechanisms controlling monocyte production and localization were altered during the systemic inflammatory response, as accumulation of monocytes in the liver and spleen developed in the absence of dramatic increases in bone marrow monocyte progenitors and was independent of chemokine (C-C motif) receptor 2 (Ccr2). Instead, TLR9-driven inflammation induced a Ccr2-independent expansion of functionally enhanced extramedullary myeloid progenitors that correlated with the peripheral accumulation of monocytes in both wild-type and Ccr2(-/-) mice. Our data implicate inflammation-induced extramedullary monocytopoiesis as a peripheral source of newly produced TLR9 responsive monocytes capable of sustaining chronic TLR9 responses in vivo. These findings help to explain how chronic TLR-mediated inflammation may be perpetuated in autoimmune diseases and increase our understanding of how monocytes are produced and positioned during systemic inflammatory responses.
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11
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Krogmann AO, Lüsebrink E, Steinmetz M, Asdonk T, Lahrmann C, Lütjohann D, Nickenig G, Zimmer S. Proinflammatory Stimulation of Toll-Like Receptor 9 with High Dose CpG ODN 1826 Impairs Endothelial Regeneration and Promotes Atherosclerosis in Mice. PLoS One 2016; 11:e0146326. [PMID: 26751387 PMCID: PMC4709087 DOI: 10.1371/journal.pone.0146326] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 12/16/2015] [Indexed: 12/11/2022] Open
Abstract
Background Toll-like receptors (TLR) of the innate immune system have been closely linked with the development of atherosclerotic lesions. TLR9 is activated by unmethylated CpG motifs within ssDNA, but also by CpG motifs in nucleic acids released during vascular apoptosis and necrosis. The role of TLR9 in vascular disease remains controversial and we sought to investigate the effects of a proinflammatory TLR9 stimulation in mice. Methods and Findings TLR9-stimulation with high dose CpG ODN at concentrations between 6.25nM to 30nM induced a significant proinflammatory cytokine response in mice. This was associated with impaired reendothelialization upon acute denudation of the carotid and increased numbers of circulating endothelial microparticles, as a marker for amplified endothelial damage. Chronic TLR9 agonism in apolipoprotein E-deficient (ApoE-/-) mice fed a cholesterol-rich diet increased aortic production of reactive oxygen species, the number of circulating endothelial microparticles, circulating sca-1/flk-1 positive cells, and most importantly augmented atherosclerotic plaque formation when compared to vehicle treated animals. Importantly, high concentrations of CpG ODN are required for these proatherogenic effects. Conclusions Systemic stimulation of TLR9 with high dose CpG ODN impaired reendothelialization upon acute vascular injury and increased atherosclerotic plaque development in ApoE-/- mice. Further studies are necessary to fully decipher the contradictory finding of TLR9 agonism in vascular biology.
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Affiliation(s)
- Alexander O. Krogmann
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
- * E-mail:
| | - Enzo Lüsebrink
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
| | - Martin Steinmetz
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
| | - Tobias Asdonk
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
| | - Catharina Lahrmann
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
| | - Dieter Lütjohann
- Institut für klinische Chemie und klinische Pharmakologie, Universität Bonn, 53125, Bonn, Germany
| | - Georg Nickenig
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
| | - Sebastian Zimmer
- Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, 53105, Bonn, Germany
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12
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Liu A, Wang Y, Ding Y, Baez I, Payne KJ, Borghesi L. Cutting Edge: Hematopoietic Stem Cell Expansion and Common Lymphoid Progenitor Depletion Require Hematopoietic-Derived, Cell-Autonomous TLR4 in a Model of Chronic Endotoxin. THE JOURNAL OF IMMUNOLOGY 2015; 195:2524-8. [PMID: 26276875 DOI: 10.4049/jimmunol.1501231] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/27/2015] [Indexed: 01/18/2023]
Abstract
Hematopoietic stem and progenitors cells (HSPCs) are activated through TLR4 in vitro. However, it remains unclear whether in vivo TLR4 sensing by HSPCs occurs directly or via other cell intermediates. In this study, we examined the cellular mechanisms underlying murine hematopoietic stem cell (HSC) expansion and common lymphoid progenitor (CLP) depletion in a model of chronic low-dose LPS. Using adoptive-transfer approaches, we show that HSC and CLP sensitivity to chronic LPS depends on hematopoietic-derived, cell subset-autonomous TLR4. Like murine progenitors, human HSPCs are activated by TLR4 in vitro. Using humanized mice, a preclinical model relevant to human physiology, we show that persistent endotoxin increases the frequency of Ki-67(+) HSCs and severely depletes CLPs and B precursors. Together, our findings show that murine HSPCs directly respond to endotoxin in vivo and that persistent LPS, a feature of several diseases of global health significance, impairs human lymphopoiesis.
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Affiliation(s)
- Ailing Liu
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Yujuan Wang
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Ying Ding
- Department of Biostatistics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15261; and
| | - Ineavely Baez
- Department of Pathology and Human Anatomy, Loma Linda University, Loma Linda, CA 92350
| | - Kimberly J Payne
- Department of Pathology and Human Anatomy, Loma Linda University, Loma Linda, CA 92350
| | - Lisa Borghesi
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261;
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