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Thioacetamide-induced liver damage and thrombocytopenia is associated with induction of antiplatelet autoantibody in mice. Sci Rep 2019; 9:17497. [PMID: 31767905 PMCID: PMC6877565 DOI: 10.1038/s41598-019-53977-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023] Open
Abstract
Thrombocytopenia is usually associated with liver injury, elevated plasma aspartate aminotransferase and alanine aminotransferase levels, and high antiplatelet immunoglobulin (Ig) titers, although the mechanism behind these effects remains elusive. Deciphering the mechanism behind acute liver disease–associated thrombocytopenia may help solve difficulties in routine patient care, such as liver biopsy, antiviral therapy, and surgery. To determine whether liver damage is sufficient per se to elicit thrombocytopenia, thioacetamide (TAA)-induced hepatitis rodent models were employed. The analysis results indicated that TAA treatment transiently induced an elevation of antiplatelet antibody titer in both rats and mice. B-cell-deficient (BCD) mice, which have loss of antibody expression, exhibited markedly less thrombocytopenia and liver damage than wild-type controls. Because TAA still induces liver damage in BCD mice, this suggests that antiplatelet Ig is one of the pathogenic factors, which play exacerbating role in the acute phase of TAA-induced hepatitis. TNF-α was differentially regulated in wild-type versus BCD mice during TAA treatment, and anti-TNF treatment drastically ameliorated antiplatelet Ig induction, thrombocytopenia, and liver injury, suggesting that the TNF pathway plays a critical role in the disease progression.
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2
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Minici C, Gounari M, Übelhart R, Scarfò L, Dühren-von Minden M, Schneider D, Tasdogan A, Alkhatib A, Agathangelidis A, Ntoufa S, Chiorazzi N, Jumaa H, Stamatopoulos K, Ghia P, Degano M. Distinct homotypic B-cell receptor interactions shape the outcome of chronic lymphocytic leukaemia. Nat Commun 2017; 8:15746. [PMID: 28598442 PMCID: PMC5472768 DOI: 10.1038/ncomms15746] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 04/25/2017] [Indexed: 01/04/2023] Open
Abstract
Cell-autonomous B-cell receptor (BcR)-mediated signalling is a hallmark feature of the neoplastic B lymphocytes in chronic lymphocytic leukaemia (CLL). Here we elucidate the structural basis of autonomous activation of CLL B cells, showing that BcR immunoglobulins initiate intracellular signalling through homotypic interactions between epitopes that are specific for each subgroup of patients with homogeneous clinicobiological profiles. The molecular details of the BcR–BcR interactions apparently dictate the clinical course of disease, with stronger affinities and longer half-lives in indolent cases, and weaker, short-lived contacts mediating the aggressive ones. The diversity of homotypic BcR contacts leading to cell-autonomous signalling reconciles the existence of a shared pathogenic mechanism with the biological and clinical heterogeneity of CLL and offers opportunities for innovative treatment strategies. Chronic lymphocytic leukaemia (CLL) is characterized by cell-autonomous B-cell receptor (BcR)-mediated signalling of neoplastic B lymphocytes. Here the authors unveil the structural basis and diversity of activatory homotypic BcR contacts and link them with CLL heterogeneity and the clinical outcome.
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Affiliation(s)
- Claudia Minici
- Biocrystallography Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132 Milan, Italy.,Università Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Maria Gounari
- B-cell Neoplasia Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | | | - Lydia Scarfò
- Università Vita-Salute San Raffaele, 20132 Milan, Italy.,B-cell Neoplasia Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy.,Strategic Research Program on CLL, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | | | - Dunja Schneider
- Centre for Biological Signaling Studies, Faculty of Biology, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany
| | | | - Alabbas Alkhatib
- Centre for Biological Signaling Studies, Faculty of Biology, Albert-Ludwigs University of Freiburg, 79104 Freiburg, Germany
| | - Andreas Agathangelidis
- B-cell Neoplasia Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Stavroula Ntoufa
- Institute of Applied Biosciences, Center for Research and Technology, 57001 Thessaloniki, Greece
| | - Nicholas Chiorazzi
- The Feinstein Institute for Medical Research, Manhasset, New York 11030, USA
| | | | - Kostas Stamatopoulos
- Institute of Applied Biosciences, Center for Research and Technology, 57001 Thessaloniki, Greece.,Department of Immunology, Genetics and Pathology, Uppsala University, 75105 Uppsala, Sweden
| | - Paolo Ghia
- Università Vita-Salute San Raffaele, 20132 Milan, Italy.,B-cell Neoplasia Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy.,Strategic Research Program on CLL, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Massimo Degano
- Biocrystallography Unit, Division of Immunology, Transplantation and Infectious Diseases, IRCCS San Raffaele Scientific Institute, via Olgettina 58, 20132 Milan, Italy
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3
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Getahun A, Beavers NA, Larson SR, Shlomchik MJ, Cambier JC. Continuous inhibitory signaling by both SHP-1 and SHIP-1 pathways is required to maintain unresponsiveness of anergic B cells. J Exp Med 2016; 213:751-69. [PMID: 27114609 PMCID: PMC4854724 DOI: 10.1084/jem.20150537] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 03/10/2016] [Indexed: 01/19/2023] Open
Abstract
Cambier et al. show that the tyrosine phosphatase SHP-1 and the inositol phosphatase SHIP-1 are required to maintain B cell anergy. Many autoreactive B cells persist in the periphery in a state of unresponsiveness called anergy. This unresponsiveness is rapidly reversible, requiring continuous BCR interaction with self-antigen and resultant regulatory signaling for its maintenance. Using adoptive transfer of anergic B cells with subsequent acute induction of gene deletion or expression, we demonstrate that the continuous activities of independent inhibitory signaling pathways involving the tyrosine phosphatase SHP-1 and the inositol phosphatase SHIP-1 are required to maintain anergy. Acute breach of anergy by compromise of either of these pathways leads to rapid cell activation, proliferation, and generation of short-lived plasma cells that reside in extrafollicular foci. Results are consistent with predicted/observed reduction in the Lyn–SHIP-1–PTEN–SHP-1 axis function in B cells from systemic lupus erythematosus patients.
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Affiliation(s)
- Andrew Getahun
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Nicole A Beavers
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Sandy R Larson
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Mark J Shlomchik
- Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - John C Cambier
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
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4
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Lang J, Ota T, Kelly M, Strauch P, Freed BM, Torres RM, Nemazee D, Pelanda R. Receptor editing and genetic variability in human autoreactive B cells. J Exp Med 2015; 213:93-108. [PMID: 26694971 PMCID: PMC4710202 DOI: 10.1084/jem.20151039] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 11/23/2015] [Indexed: 12/11/2022] Open
Abstract
Lang et al. show in a humanized mouse model that human B cells undergo central tolerance via a combination of receptor editing and clonal deletion. The mechanisms by which B cells undergo tolerance, such as receptor editing, clonal deletion, and anergy, have been established in mice. However, corroborating these mechanisms in humans remains challenging. To study how autoreactive human B cells undergo tolerance, we developed a novel humanized mouse model. Mice expressing an anti–human Igκ membrane protein to serve as a ubiquitous neo self-antigen (Ag) were transplanted with a human immune system. By following the fate of self-reactive human κ+ B cells relative to nonautoreactive λ+ cells, we show that tolerance of human B cells occurs at the first site of self-Ag encounter, the bone marrow, via a combination of receptor editing and clonal deletion. Moreover, the amount of available self-Ag and the genetics of the cord blood donor dictate the levels of central tolerance and autoreactive B cells in the periphery. Thus, this model can be useful for studying specific mechanisms of human B cell tolerance and to reveal differences in the extent of this process among human populations.
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Affiliation(s)
- Julie Lang
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Takayuki Ota
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Margot Kelly
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Pamela Strauch
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - Brian M Freed
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Division of Allergy and Clinical Immunology, University of Colorado Denver School of Medicine, Aurora, CO 80045
| | - Raul M Torres
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
| | - David Nemazee
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Roberta Pelanda
- Department of Immunology and Microbiology, University of Colorado Denver School of Medicine, Aurora, CO 80045 Department of Biomedical Research, National Jewish Health, Denver, CO 80206
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Two types of BCR interactions are positively selected during leukemia development in the Eμ-TCL1 transgenic mouse model of CLL. Blood 2015; 125:1578-88. [PMID: 25564405 DOI: 10.1182/blood-2014-07-587790] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Chronic lymphocytic leukemia (CLL) is a common B-cell malignancy characterized by a highly variable course and outcome. The disease is believed to be driven by B-cell receptor (BCR) signals generated by external antigens and/or cell-autonomous BCR interactions, but direct in vivo evidence for this is still lacking. To further define the role of the BCR pathway in the development and progression of CLL, we evaluated the capacity of different types of antigen/BCR interactions to induce leukemia in the Eμ-TCL1 transgenic mouse model. We show that cell autonomous signaling capacity is a uniform characteristic of the leukemia-derived BCRs and represents a prerequisite for CLL development. Low-affinity BCR interactions with autoantigens generated during apoptosis are also positively selected, suggesting that they contribute to the pathogenesis of the disease. In contrast, high-affinity BCR interactions are not selected, regardless of antigen form or presentation. We also show that the capacity of the leukemic cells to respond to cognate antigen correlates inversely with time to leukemia development, suggesting that signals induced by external antigen increase the aggressiveness of the disease. Collectively, these findings provide in vivo evidence that the BCR pathway drives the development and can influence the clinical course of CLL.
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Lee SR, Rutan JA, Monteith AJ, Jones SZ, Kang SA, Krum KN, Kilmon MA, Roques JR, Wagner NJ, Clarke SH, Vilen BJ. Receptor cross-talk spatially restricts p-ERK during TLR4 stimulation of autoreactive B cells. THE JOURNAL OF IMMUNOLOGY 2012; 189:3859-68. [PMID: 22984080 DOI: 10.4049/jimmunol.1200940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To maintain tolerance, autoreactive B cells must regulate signal transduction from the BCR and TLRs. We recently identified that dendritic cells and macrophages regulate autoreactive cells during TLR4 activation by releasing IL-6 and soluble CD40 ligand (sCD40L). These cytokines selectively repress Ab secretion from autoreactive, but not antigenically naive, B cells. How IL-6 and sCD40L repress autoantibody production is unknown. In this work, we show that IL-6 and sCD40L are required for low-affinity/avidity autoreactive B cells to maintain tolerance through a mechanism involving receptor cross-talk between the BCR, TLR4, and the IL-6R or CD40. We show that acute signaling through IL-6R or CD40 integrates with chronic BCR-mediated ERK activation to restrict p-ERK from the nucleus and represses TLR4-induced Blimp-1 and XBP-1 expression. Tolerance is disrupted in 2-12H/MRL/lpr mice where IL-6 and sCD40L fail to spatially restrict p-ERK and fail to repress TLR4-induced Ig secretion. In the case of CD40, acute signaling in B cells from 2-12H/MRL/lpr mice is intact, but the chronic activation of p-ERK emanating from the BCR is attenuated. Re-establishing chronically active ERK through retroviral expression of constitutively active MEK1 restores tolerance upon sCD40L, but not IL-6, stimulation, indicating that regulation by IL-6 requires another signaling effector. These data define the molecular basis for the regulation of low-affinity autoreactive B cells during TLR4 stimulation; they explain how autoreactive but not naive B cells are repressed by IL-6 and sCD40L; and they identify B cell defects in lupus-prone mice that lead to TLR4-induced autoantibody production.
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Affiliation(s)
- Sang-Ryul Lee
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
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7
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Gilbert MR, Wagner NJ, Jones SZ, Wisz AB, Roques JR, Krum KN, Lee SR, Nickeleit V, Hulbert C, Thomas JW, Gauld SB, Vilen BJ. Autoreactive preplasma cells break tolerance in the absence of regulation by dendritic cells and macrophages. THE JOURNAL OF IMMUNOLOGY 2012; 189:711-20. [PMID: 22675201 DOI: 10.4049/jimmunol.1102973] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The ability to induce Ab responses to pathogens while maintaining the quiescence of autoreactive cells is an important aspect of immune tolerance. During activation of TLR4, dendritic cells (DCs) and macrophages (MFs) repress autoantibody production through their secretion of IL-6 and soluble CD40L (sCD40L). These soluble mediators selectively repress B cells chronically exposed to Ag, but not naive cells, suggesting a means to maintain tolerance during TLR4 stimulation, yet allow immunity. In this study, we identify TNF-α as a third repressive factor, which together with IL-6 and CD40L account for nearly all the repression conferred by DCs and MFs. Similar to IL-6 and sCD40L, TNF-α did not alter B cell proliferation or survival. Instead, it reduced the number of Ab-secreting cells. To address whether the soluble mediators secreted by DCs and MFs functioned in vivo, we generated mice lacking IL-6, CD40L, and TNF-α. Compared to wild-type mice, these mice showed prolonged anti-nuclear Ab responses following TLR4 stimulation. Furthermore, adoptive transfer of autoreactive B cells into chimeric IL-6(-/-) × CD40L(-/-) × TNF-α(-/-) mice showed that preplasma cells secreted autoantibodies independent of germinal center formation or extrafollicular foci. These data indicate that in the absence of genetic predisposition to autoimmunity, loss of endogenous IL-6, CD40L, and TNF-α promotes autoantibody secretion during TLR4 stimulation.
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Affiliation(s)
- Mileka R Gilbert
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
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8
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Quách TD, Manjarrez-Orduño N, Adlowitz DG, Silver L, Yang H, Wei C, Milner ECB, Sanz I. Anergic responses characterize a large fraction of human autoreactive naive B cells expressing low levels of surface IgM. THE JOURNAL OF IMMUNOLOGY 2011; 186:4640-8. [PMID: 21398610 DOI: 10.4049/jimmunol.1001946] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
B cell anergy represents an important mechanism of peripheral immunological tolerance for mature autoreactive B cells that escape central tolerance enforced by receptor editing and clonal deletion. Although well documented in mice, the extent of its participation in human B cell tolerance remains to be fully established. In this study, we characterize the functional behavior of strictly defined human naive B cells separated on the basis of their surface IgM (sIgM) expression levels. We demonstrate that cells with lower sIgM levels (IgM(lo)) are impaired in their ability to flux calcium in response to either anti-IgM or anti-IgD cross-linking and contain a significantly increased frequency of autoreactive cells compared with naive B cells with higher levels of sIgM. Phenotypically, in healthy subjects, IgM(lo) cells are characterized by the absence of activation markers, reduction of costimulatory molecules (CD19 and CD21), and increased levels of inhibitory CD22. Functionally, IgM(lo) cells display significantly weaker proliferation, impaired differentiation, and poor Ab production. In aggregate, the data indicate that hyporesponsiveness to BCR cross-linking associated with sIgM downregulation is present in a much larger fraction of all human naive B cells than previously reported and is likely to reflect a state of anergy induced by chronic autoantigen stimulation. Finally, our results indicate that in systemic lupus erythematosus patients, naive IgM(lo) cells display increased levels of CD95 and decreased levels of CD22, a phenotype consistent with enhanced activation of autoreactive naive B cells in this autoimmune disease.
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Affiliation(s)
- Tâm D Quách
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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9
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Abstract
B cells represent an important link between the adaptive and innate immune systems as they express both antigen-specific B-cell receptors (BCRs) as well as various Toll-like receptors (TLRs). Several checkpoints in B-cell development ensure that self-specific cells are eliminated from the mature B-cell repertoire to avoid harmful autoreactive responses. These checkpoints are controlled by BCR-mediated events but are also influenced by TLR-dependent signals from the innate immune system. Additionally, B-cell-intrinsic and extrinsic TLR signaling are critical for inflammatory events required for the clearance of microbial infections. Factors secreted by TLR-activated macrophages or dendritic cells directly influence the fate of protective and autoreactive B cells. Additionally, naive and memory B cells respond differentially to TLR ligands, as do different B-cell subsets. We review here recent literature describing intrinsic and extrinsic effects of TLR stimulation on the fate of B cells, with particular attention to autoimmune diseases.
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Affiliation(s)
- Steve P Crampton
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
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10
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Sauerborn M, Schellekens H. B-1 cells and naturally occurring antibodies: influencing the immunogenicity of recombinant human therapeutic proteins? Curr Opin Biotechnol 2009; 20:715-21. [PMID: 19892544 DOI: 10.1016/j.copbio.2009.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 10/14/2009] [Indexed: 12/18/2022]
Abstract
Recombinant human therapeutic proteins are increasingly being used to treat serious and life-threatening diseases like multiple sclerosis, diabetes mellitus, and cancer. An important side effect of these proteins is the development of antidrug antibodies, which can be neutralizing and thus interfere with the efficacy and safety of the drug. Some biophysical properties, for example, aggregation, also can initiate the immunogenic response to human therapeutics. Many other factors including patients' characteristics may influence this response. Besides induced antibodies, autoantibodies (i.e. naturally occurring antibodies [NAs]) against therapeutic relevant proteins in naïve patients are increasingly being identified. The role of autoreactive B cells and their escape from deletion, production of NAs and their pivotal function in the immune system, the dualistic role of B-1 cells in autoimmunity, and the influence of NAs on disease outcome and their possible impact on the efficacy of human therapeutics will be presented and discussed.
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Affiliation(s)
- Melody Sauerborn
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, 3584 CA Utrecht, The Netherlands.
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Khatami M. Inflammation, aging, and cancer: tumoricidal versus tumorigenesis of immunity: a common denominator mapping chronic diseases. Cell Biochem Biophys 2009; 55:55-79. [PMID: 19672563 DOI: 10.1007/s12013-009-9059-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 06/30/2009] [Indexed: 12/18/2022]
Abstract
Acute inflammation is a highly regulated defense mechanism of immune system possessing two well-balanced and biologically opposing arms termed apoptosis ('Yin') and wound healing ('Yang') processes. Unresolved or chronic inflammation (oxidative stress) is perhaps the loss of balance between 'Yin' and 'Yang' that would induce co-expression of exaggerated or 'mismatched' apoptotic and wound healing factors in the microenvironment of tissues ('immune meltdown'). Unresolved inflammation could initiate the genesis of many age-associated chronic illnesses such as autoimmune and neurodegenerative diseases or tumors/cancers. In this perspective 'birds' eye' view of major interrelated co-morbidity risk factors that participate in biological shifts of growth-arresting ('tumoricidal') or growth-promoting ('tumorigenic') properties of immune cells and the genesis of chronic inflammatory diseases and cancer will be discussed. Persistent inflammation is perhaps a common denominator in the genesis of nearly all age-associated health problems or cancer. Future challenging opportunities for diagnosis, prevention, and/or therapy of chronic illnesses will require an integrated understanding and identification of developmental phases of inflammation-induced immune dysfunction and age-associated hormonal and physiological readjustments of organ systems. Designing suitable cohort studies to establish the oxido-redox status of adults may prove to be an effective strategy in assessing individual's health toward developing personal medicine for healthy aging.
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Affiliation(s)
- Mahin Khatami
- The National Cancer Institute, The National Institutes of Health, Bethesda, MD, USA.
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12
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Abstract
Systemic lupus erythematosus (SLE) highlights the dangers of dysregulated B cells and the importance of initiating and maintaining tolerance. In addition to central deletion, receptor editing, peripheral deletion, receptor revision, anergy, and indifference, we have described a new mechanism of B cell tolerance wherein dendritic cells (DCs) and macrophages (MPhis) regulate autoreactive B cells during innate immune responses. In part, DCs and MPhis repress autoreactive B cells by releasing IL-6 and soluble CD40L (sCD40L). This mechanism is selective in that IL-6 and sCD40L do not affect Ig secretion by naïve cells during innate immune responses, allowing immunity in the absence of autoimmunity. In lupus-prone mice, DCs and MPhis are defective in secretion of IL-6 and sCD40L and cannot effectively repress autoantibody secretion suggesting that defects in DC/MPhi-mediated tolerance may contribute to the autoimmune phenotype. Further, these studies suggest that reconstituting DCs and MPhis in SLE patients might restore regulation of autoreactive B cells and provide an alternative to immunosuppressive therapies.
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Affiliation(s)
- Barbara J Vilen
- Department of Microbiology, University of North Carolina, CB 7290, Chapel Hill, NC 27599, USA.
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