Immunology
Abstract
The roles of macrophages in orchestrating innate immunity through phagocytosis and T lymphocyte activation have been extensively investigated. Much less understood is the unexpected role of macrophages in direct tumor regression. Tumoricidal macrophages can indeed manifest cancer immunoediting activity in the absence of adaptive immunity. We investigated direct macrophage cytotoxicity in malignant pleural mesothelioma, a lethal cancer that develops from mesothelial cells of the pleural cavity after occupational asbestos exposure. In particular, we analyzed the cytotoxic activity of mouse RAW264.7 macrophages upon cell-cell contact with autologous AB1/AB12 mesothelioma cells. We show that macrophages killed mesothelioma cells by oxeiptosis via a mechanism involving enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27–specific (H3K27-specific) methyltransferase of the polycomb repressive complex 2 (PRC2). A selective inhibitor of EZH2 indeed impaired RAW264.7-directed cytotoxicity and concomitantly stimulated the PD-1 immune checkpoint. In the immunocompetent BALB/c model, RAW264.7 macrophages pretreated with the EZH2 inhibitor failed to control tumor growth of AB1 and AB12 mesothelioma cells. Blockade of PD-1 engagement restored macrophage-dependent antitumor activity. We conclude that macrophages can be directly cytotoxic for mesothelioma cells independent of phagocytosis. Inhibition of the PRC2 EZH2 methyltransferase reduces this activity because of PD-1 overexpression. Combination of PD-1 blockade and EZH2 inhibition restores macrophage cytotoxicity.
Authors
Malik Hamaidia, Hélène Gazon, Clotilde Hoyos, Gabriela Brunsting Hoffmann, Renaud Louis, Bernard Duysinx, Luc Willems
Abstract
Tissue engineering is a promising approach to address organ shortages currently limiting clinical transplantation. “Off-the-shelf” engineered vascularized organs will likely use allogeneic endothelial cells (ECs) to construct microvessels required for graft perfusion. Vasculogenic ECs can be differentiated from committed progenitors (human endothelial colony forming cells or HECFCs) without risk of mutation or teratoma formation associated with reprogrammed stem cells. Like other ECs, these cells basally express both class I and class II major histocompatibility complex (MHC) molecules, bind donor-specific antibody (DSA), activate alloreactive T effector memory cells, and initiate rejection in the absence of donor leukocytes. We report here that CRISPR/Cas9-mediated dual ablation of β2-microglobulin and CIITA in HECFC-derived ECs eliminates both class I and II MHC expression while retaining EC functions and vasculogenic potential. Importantly, dually ablated ECs no longer bind human DSA or activate allogeneic CD4+ effector memory T cells and are resistant to killing by CD8+ alloreactive cytotoxic T lymphocytes in vitro and in vivo. Despite absent class I MHC molecules, these ECs do not activate or elicit cytotoxic activity from allogeneic natural killer cells. These data suggest that HECFC-derived ECs lacking MHC molecule expression can be utilized for engineering vascularized grafts that evade allorejection.
Authors
Jonathan Merola, Melanie Reschke, Richard W. Pierce, Lingfeng Qin, Susann Spindler, Tania Baltazar, Thomas D. Manes, Francesc Lopez-Giraldez, Guangxin Li, Laura G. Bracaglia, Catherine Xie, Nancy Kirkiles-Smith, W. Mark Saltzman, Gregory T. Tietjen, George Tellides, Jordan S. Pober
Abstract
`NK cell–mediated regulation of antigen-specific T cells can contribute to and exacerbate chronic viral infection, but the protective mechanisms against NK cell–mediated attack on T cell immunity are poorly understood. Here, we show that progranulin (PGRN) can reduce NK cell cytotoxicity through reduction of NK cell expansion, granzyme B transcription, and NK cell–mediated lysis of target cells. Following infection with the lymphocytic choriomeningitis virus (LCMV), PGRN levels increased — a phenomenon dependent on the presence of macrophages and type I IFN signaling. Absence of PGRN in mice (Grn–/–) resulted in enhanced NK cell activity, increased NK cell–mediated killing of antiviral T cells, reduced antiviral T cell immunity, and increased viral burden, culminating in increased liver immunopathology. Depletion of NK cells restored antiviral immunity and alleviated pathology during infection in Grn–/– mice. In turn, PGRN treatment improved antiviral T cell immunity. Taken together, we identified PGRN as a critical factor capable of reducing NK cell–mediated attack of antiviral T cells.
Authors
Anfei Huang, Prashant V. Shinde, Jun Huang, Tina Senff, Haifeng C. Xu, Cassandra Margotta, Dieter Häussinger, Thomas E. Willnow, Jinping Zhang, Aleksandra A. Pandyra, Jörg Timm, Sascha Weggen, Karl S. Lang, Philipp A. Lang
Abstract
Chagas disease is a life-long pathology resulting from Trypanosoma cruzi infection. It represents one of the most frequent causes of heart failure and sudden death in Latin America. Herein we provide evidence that aerobic glycolytic pathway activation in monocytes drives nitric oxide (NO) production, triggering tyrosine nitration (TN) on CD8 T cells and dysfunction in patients with chronic Chagas disease. Monocytes from patients exhibited higher frequency of hypoxia inducible factor (HIF)-1α and increased expression of its target genes/proteins. Non-classical monocytes are expanded in patients´ peripheral blood and represent an important source of NO. Monocytes entail CD8 T cell surface nitration since both the frequency of non-classical monocytes and that of NO-producing monocytes, positively correlated with the percentage of TN+ lymphocytes. Inhibition of glycolysis in (in vitro) infected peripheral blood mononuclear cells decreased the inflammatory properties of monocytes/macrophages diminishing the frequency of IL-1β- and NO-producing cells. In agreement, glycolysis inhibition reduced the percentage of TN+CD8 T cells improving their functionality. Altogether, these results clearly evidence that glycolysis governs oxidative stress on monocytes and modulates monocyte-T cell interplay in human chronic Chagas disease. Understanding the pathological immune mechanisms that sustains inflammatory environment in human pathology is key to design improved therapies.
Authors
Liliana María Sanmarco, Natalia Eberhardt, Gastón Bergero, Luz Piedad Quebrada Palacio, Pamela Martino Adami, Laura Marina Visconti, Ángel Ramón Minguez, Yolanda Hernández-Vasquez, Eugenio Antonio Carrera Silva, Laura Morelli, Miriam Postan, Maria Pilar Aoki
Abstract
Long-term survivors post hematopoietic stem cell transplantation are at high risk of infection which accounts for one-third of all deaths. Little is known about the cause of inferior host defense after immune cell reconstitution. Here, we exploited a murine syngeneic bone marrow transplantation (BMT) model of late infection with gammaherpesvirus 68 (MHV-68) to determine the role of conventional dendritic cell (cDC) trafficking in adaptive immunity in BMT mice. Post infection, the expression of chemokine Ccl21 in the lung is reduced and the migration of cDCs into lung draining lymph nodes (dLNs) is impaired in BMT mice, limiting the opportunity for cDCs to prime Th cells in the dLNs. While cDC subsets are redundant in priming Th1 cells, Notch2 functions in cDC2s are required for priming increased Th17 responses in BMT mice and cDC1s can lessen this activity. Importantly, Th17 cells can be primed both in the lungs and dLNs, allowing for increased Th17 responses without optimum cDC trafficking in BMT mice. Taken together, impaired cDC trafficking in BMT mice reduces protective Th1 responses and allows increased pathogenic Th17 responses. Thus, we have revealed a previously unknown mechanism for BMT procedures to cause long-term inferior immune responses to herpes viral infection.
Authors
Carol A. Wilke, Matthew M. Chadwick, Paul R. Chan, Bethany B. Moore, Xiaofeng Zhou
Abstract
CD8+ tumor-infiltrating lymphocytes (TILs) correlate with relapse-free survival (RFS) in most cancer types, including breast cancer. However, subset composition, functional status, and spatial location of CD8+ TILs in relation to RFS in human breast tumors remain unclear. Spatial tissue analysis via quantitative immunofluorescence showed that infiltration of CD8+ T cells into cancer islands is more significantly associated with RFS than CD8+ T cell infiltration into either tumor stroma or total tumor. Localization into cancer islands within tumors is mediated by expression of the integrin CD103, which is a marker for tissue resident memory T cells (TRMs). Analysis of fresh tumor samples revealed that CD8+ TRMs are functionally similar to other CD8+ TILs, suggesting that the basis of their protective effect is their spatial distribution rather than functional differences. Indeed, CD103+ TRMs, as compared to CD103- CD8+ TILs, are enriched within cancer islands and CD8+ TRM proximity to cancer cells drives the association of CD8+ TIL densities with RFS. Together, these findings reveal the importance of cancer island localized CD8+ TRMs in surveillance of the breast tumor microenvironment and as a critical determinant of RFS in breast cancer patients.
Authors
Colt A. Egelston, Christian Avalos, Travis Y. Tu, Anthony Rosario, Roger Wang, Shawn Solomon, Gayathri Srinivasan, Michael S. Nelson, Yinghui Huang, Min Hui Lim, Diana L. Simons, Ting-Fang He, John H. Yim, Laura Kruper, Joanne Mortimer, Susan Yost, Weihua Guo, Christopher Ruel, Paul H. Frankel, Yuan Yuan, Peter P. Lee
Abstract
Macrophage activation is implicated in the development of pulmonary fibrosis by generation of profibrotic molecules. Although NADPH oxidase 4 (NOX4) is known to contribute to pulmonary fibrosis, its effects on macrophage activation and mitochondrial redox signaling are unclear. Here, we show that NOX4 is crucial for lung macrophage profibrotic polarization and fibrotic repair after asbestos exposure. NOX4 was elevated in lung macrophages from subjects with asbestosis, and mice harboring a deletion of NOX4 in lung macrophages were protected from asbestos-induced fibrosis. NOX4 promoted lung macrophage profibrotic polarization and increased production of profibrotic molecules that induce collagen deposition. Mechanistically, NOX4 further augmented mitochondrial ROS production and induced mitochondrial biogenesis. Targeting redox signaling and mitochondrial biogenesis prevented the profibrotic polarization of lung macrophages by reducing the production of profibrotic molecules. These observations provide evidence that macrophage NOX4 is a potentially novel therapeutic target to halt the development of asbestos-induced pulmonary fibrosis.
Authors
Chao He, Jennifer L. Larson-Casey, Dana Davis, Vidya Sagar Hanumanthu, Ana Leda F. Longhini, Victor J. Thannickal, Linlin Gu, A. Brent Carter
Abstract
BACKGROUND Cytokine biomarkers have already been used to predict acute graft-versus-host disease (aGVHD) onset, nonrelapse mortality, and overall survival in human and mouse models, but the consistency of the consequences between patients and mice has not been evaluated. Furthermore, no study about any biomarker or biomarker panel for aGVHD grading or steroid sensitivity of aGVHD patients simultaneously has been reported.METHODS Here we established an aGVHD mouse model and explored the relation between aGVHD onset and variations of some cytokines. Based on the results and latest progress, we selected 16 cytokines and compared their serum variations in aGVHD patients and non-aGVHD patients after allogeneic hematopoietic stem cell transplantation. Using protein microarray, we explored the relation between the cytokine levels and aGVHD-related events (onset, grading, and steroid sensitivity).RESULTS The increase of chemokine levels in murine aGVHD was very consistent with that of patients. We found obviously higher levels of IL-2, IL-4, Elafin, sST2, TLR4, and TNF-α, and lower levels of TGF-β in both aGVHD mouse models and aGVHD patients. In addition, patients with severe aGVHD showed increased IL-6, TLR4, TNF receptor 1 (TNFR1), and Elafin and decreased TGF-β. TLR4 and TNFR1 were significantly increased in steroid-refractory aGVHD patients compared with steroid-effective patients (P < 0.05).CONCLUSION A combination of TLR4, TNFR1, TGF-β, and Elafin could be a new 4-biomarker panel to assist aGVHD diagnosis, grading, and evaluation of steroid sensitivity for clinical aGVHD patients.TRIAL REGISTRATION ChiCTR1900022292 “Clinical Research of Umbilical Cord–Derived Mesenchymal Stromal Cells in the Prophylaxis of Graft-Versus-Host Disease After HLA-Haploidentical Stem-Cell Transplantation.”FUNDING National Key Research Program, National Natural Science Foundation of China, Chongqing Social Career and People’s Livelihood Security Science and Technology Innovation Project, Fundamental and Frontier Research Program of Chongqing, and Foundation of Xinqiao Hospital.
Authors
Xiaoping Li, Ting Chen, Qiangguo Gao, Wei Zhang, Yunshuo Xiao, Wen Zhu, Lingyu Zeng, Zhenyu Li, Shijie Yang, Rui Wang, Xiaoqi Wang, Yimei Feng, Xi Zhang
Abstract
Multiple organ failure (MOF) is the leading cause of late mortality and morbidity in patients who are admitted to intensive care units (ICUs). However, there is an epidemiologic discrepancy in the mechanism of underlying immunologic derangement dependent on etiology between sepsis and trauma patients in MOF. We hypothesized that damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), while both involved in the development of MOF, contribute differently to the systemic innate immune derangement and coagulopathic changes. We found that DAMPs not only produce weaker innate immune activation than counterpart PAMPs, but also induce less TLR signal desensitization, contribute to less innate immune cell death, and propagate more robust systemic coagulopathic effects than PAMPs. This differential contribution to MOF provides further insight into the contributing factors to late mortality in critically ill trauma and sepsis patients. These findings will help to better prognosticate patients at risk of MOF and may provide future therapeutic molecular targets in this disease process.
Authors
John Eppensteiner, Jean Kwun, Uwe Scheuermann, Andrew Barbas, Alexander T. Limkakeng, Maggie Kuchibhatla, Eric A. Elster, Allan D. Kirk, Jaewoo Lee
Abstract
T follicular regulatory (TFR) cells are found in the germinal center (GC) response and help shape the antibody (Ab) response. However, the precise role of TFR cells in the GC is controversial. Here, we addressed TFR cell function using mice with impaired TFR cell development (Bcl6-flox/Foxp3-cre, or Bcl6FC mice), mice with augmented TFR cell development (Blimp1-flox/Foxp3-cre, or Blimp1FC mice), and two different methods of immunization. Unexpectedly, GC B cell levels positively correlated with TFR cell levels. Using a gene profiling approach, we found that TFH cells from TFR-deficient mice showed strong upregulation of granzyme B (Gzmb) and other effector CD8+ T cell genes, many of which were Stat4 dependent. The upregulation of cytotoxic genes was the highest in TFH cells from TFR-deficient mice where Blimp1 was also deleted in Foxp3+ regulatory T cells (Bcl6-flox/Prdm1-flox/Foxp3-cre [DKO] mice). Granzyme B– and Eomesodermin-expressing TFH cells correlated with a higher rate of apoptotic GC B cells. Klrg1+ TFH cells from DKO mice expressed higher levels of Gzmb. Our data show that TFR cells repress the development of abnormal cytotoxic TFH cells, and the presence of cytotoxic TFH cells correlates with a lower GC and Ab response. Our data show what we believe is a novel mechanism of action for TFR cells helping the GC response.
Authors
Markus M. Xie, Shuyi Fang, Qiang Chen, Hong Liu, Jun Wan, Alexander L. Dent
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