Immunology
Abstract
The mechanistic target of rapamycin complex 2 (mTORC2) is a potentially novel and promising anticancer target due to its critical roles in proliferation, apoptosis, and metabolic reprogramming of cancer cells. However, the activity and function of mTORC2 in distinct cells within malignant tissue in vivo is insufficiently explored. Surprisingly, in primary human and mouse colorectal cancer (CRC) samples, mTORC2 signaling could not be detected in tumor cells. In contrast, only macrophages in tumor-adjacent areas showed mTORC2 activity, which was downregulated in stromal macrophages residing within human and mouse tumor tissues. Functionally, inhibition of mTORC2 by specific deletion of Rictor in macrophages stimulated tumorigenesis in a colitis-associated CRC mouse model. This phenotype was driven by a proinflammatory reprogramming of mTORC2-deficient macrophages that promoted colitis via the cytokine SPP1/osteopontin to stimulate tumor growth. In human CRC patients, high SPP1 levels and low mTORC2 activity in tumor-associated macrophages correlated with a worsened clinical prognosis. Treatment of mice with a second-generation mTOR inhibitor that inhibits mTORC2 and mTORC1 exacerbated experimental colorectal tumorigenesis in vivo. In conclusion, mTORC2 activity is confined to macrophages in CRC and limits tumorigenesis. These results suggest activation but not inhibition of mTORC2 as a therapeutic strategy for colitis-associated CRC.
Authors
Karl Katholnig, Birgit Schütz, Stephanie D. Fritsch, David Schörghofer, Monika Linke, Nyamdelger Sukhbaatar, Julia M. Matschinger, Daniela Unterleuthner, Martin Hirtl, Michaela Lang, Merima Herac, Andreas Spittler, Andreas Bergthaler, Gernot Schabbauer, Michael Bergmann, Helmut Dolznig, Markus Hengstschläger, Mark A. Magnuson, Mario Mikula, Thomas Weichhart
Abstract
Lung cancer remains the leading cause of cancer-related death in the United States. Although the alveolar macrophage (AM) comprises the major resident immune cell in the lung, few studies have investigated its role in lung cancer development. We recently discovered a potentially novel mechanism wherein AMs regulate STAT-induced inflammatory responses in neighboring epithelial cells (ECs) via secretion and delivery of suppressors of cytokine signaling 3 (SOCS3) within extracellular vesicles (EVs). Here, we explored the impact of SOCS3 transfer on EC tumorigenesis and the integrity of AM SOCS3 secretion during development of lung cancer. AM-derived EVs containing SOCS3 inhibited STAT3 activation as well as proliferation and survival of lung adenocarcinoma cells. Levels of secreted SOCS3 were diminished in lungs of patients with non–small cell lung cancer and in a mouse model of lung cancer, and the impaired ability of murine AMs to secrete SOCS3 within EVs preceded the development of lung tumors. Loss of this homeostatic brake on tumorigenesis prompted our effort to “rescue” it. Provision of recombinant SOCS3 loaded within synthetic liposomes inhibited proliferation and survival of lung adenocarcinoma cells in vitro as well as malignant transformation of normal ECs. Intratumoral injection of SOCS3 liposomes attenuated tumor growth in a lung cancer xenograft model. This work identifies AM-derived vesicular SOCS3 as an endogenous antitumor mechanism that is disrupted within the tumor microenvironment and whose rescue by synthetic liposomes can be leveraged as a potential therapeutic strategy for lung cancer.
Authors
Jennifer M. Speth, Loka R. Penke, Joseph D. Bazzill, Kyung Soo Park, Rafael Gil de Rubio, Daniel J. Schneider, Hideyasu Ouchi, James J. Moon, Venkateshwar G. Keshamouni, Rachel L. Zemans, Vibha N. Lama, Douglas A. Arenberg, Marc Peters-Golden
Abstract
Background: Innate immune activation impacts lung transplant outcomes. Dectin-1 is an innate receptor important for pathogen recognition. We hypothesized that genotypes reducing dectin-1 activity would be associated with infection, graft dysfunction, and death in lung transplant recipients. Methods: We assessed the rs16910526 CLEC7A gene polymorphism Y238X, which results in dectin-1 truncation, in 321 lung allograft recipients at a single institution and in 1,129 lung allograft recipients in the multi-center lung transplant outcomes group (LTOG) cohort. Differences in dectin-1 mRNA, cytokines, protein levels, immunophenotypes, and clinical factors were assessed. Results: Y238X carriers had decreased dectin-1 mRNA expression (P = 0.0001), decreased soluble dectin-1 protein concentrations in BAL (P = 0.008) and plasma (P = 0.04), and decreased monocyte surface dectin-1 (P = 0.01) compared to wild type subjects. Y238X carriers had an increased risk of fungal pathogens (HR 1.17, CI 1.0 – 1.4), an increased risk of graft dysfunction or death (HR 1.6, CI 1.0 – 2.6), as well increased mortality in the UCSF cohort (HR 1.8, CI 1.1 – 3.8) and in the LTOG cohort (HR 1.3, CI 1.1 – 1.6), compared to CLEC7A wildtype subjects. Conclusion: Increased rates of graft dysfunction and death associated with this dectin-1 polymorphism may be amplified by immunosuppression that drives higher fungal burden from compromised pathogen recognition. Funding: Project funding came from the UCSF Nina Ireland Program for Lung Health (NIPLH) Innovative Grant program, award number IK2CX001034 from the Clinical Sciences Research & Development Service of the VA Office of Research and Development, and the Joel D. Cooper Career Development Award from the International Society for Heart and Lung Transplantation.
Authors
Daniel R. Calabrese, Ping Wang, Tiffany Chong, Jonathan Hoover, Jonathan P. Singer, Dara Torgerson, Steven R. Hays, Jeffrey A. Golden, Jasleen Kukreja, Daniel Dugger, Jason D. Christie, LTOG investigators, John R. Greenland
Abstract
B7-H4 is a negative regulatory B7 family member. We investigated the role of host and donor B7-H4 in regulating acute graft-versus-host disease (GVHD). Allogeneic donor T cells infused into B7-H4–/– versus WT recipients markedly accelerated GVHD-induced lethality. Chimera studies pointed toward B7-H4 expression on host hematopoietic cells as more critical than parenchymal cells in controlling GVHD. Rapid mortality in B7-H4–/– recipients was associated with increased donor T cell expansion, gut T cell homing and loss of intestinal epithelial integrity, increased T effector function (proliferation, proinflammatory cytokines, cytolytic molecules), and reduced apoptosis. Higher metabolic demands of rapidly proliferating donor T cells in B7-H4–/– versus WT recipients required multiple metabolic pathways, increased extracellular acidification rates (ECARs) and oxygen consumption rates (OCRs), and increased expression of fuel substrate transporters. During GVHD, B7-H4 expression was upregulated on allogeneic WT donor T cells. B7-H4–/– donor T cells given to WT recipients increased GVHD mortality and had function and biological properties similar to WT T cells from allogeneic B7-H4–/– recipients. Graft-versus-leukemia responses were intact regardless as to whether B7-H4–/– mice were used as hosts or donors. Taken together, these data provide new insights into the negative regulatory processes that control GVHD and provide support for developing therapeutic strategies directed toward the B7-H4 pathway.
Authors
Asim Saha, Patricia A. Taylor, Christopher J. Lees, Angela Panoskaltsis-Mortari, Mark J. Osborn, Colby J. Feser, Govindarajan Thangavelu, Wolfgang Melchinger, Yosef Refaeli, Geoffrey R. Hill, David H. Munn, William J. Murphy, Jonathan S. Serody, Ivan Maillard, Katharina Kreymborg, Marcel van den Brink, Chen Dong, Shuyu Huang, Xingxing Zang, James P. Allison, Robert Zeiser, Bruce R. Blazar
Abstract
Immune checkpoint blockade has revolutionized cancer treatment. Patients developing immune mediated adverse events, such as colitis, appear to particularly benefit from immune checkpoint inhibition. Yet, the contributing mechanisms are largely unknown. We identified a systemic LPS signature in melanoma patients with colitis following anti–cytotoxic T lymphocyte–associated antigen 4 (anti–CTLA-4) checkpoint inhibitor treatment and hypothesized that intestinal microbiota–derived LPS contributes to therapeutic efficacy. Because activation of immune cells within the tumor microenvironment is considered most promising to effectively control cancer, we analyzed human and murine melanoma for known sentinels of LPS. We identified mast cells (MCs) accumulating in and around melanomas and showed that effective melanoma immune control was dependent on LPS-activated MCs recruiting tumor-infiltrating effector T cells by secretion of CXCL10. Importantly, CXCL10 was also upregulated in human melanomas with immune regression and in patients with colitis induced by anti–CTLA-4 antibody. Furthermore, we demonstrate that CXCL10 upregulation and an MC signature at the site of melanomas are biomarkers for better patient survival. These findings provide conclusive evidence for a “Trojan horse treatment strategy” in which the plasticity of cancer-resident immune cells, such as MCs, is used as a target to boost tumor immune defense.
Authors
Susanne Kaesler, Florian Wölbing, Wolfgang Eberhard Kempf, Yuliya Skabytska, Martin Köberle, Thomas Volz, Tobias Sinnberg, Teresa Amaral, Sigrid Möckel, Amir Yazdi, Gisela Metzler, Martin Schaller, Karin Hartmann, Benjamin Weide, Claus Garbe, Hans-Georg Rammensee, Martin Röcken, Tilo Biedermann
Abstract
Background: Hydroxymethyl-glutaryl-coenzyme A reductase inhibitors (‘statins’) are prescribed to millions of people. Statins are anti-inflammatory independent of their cholesterol-reducing effects. To date, most reports on the immune effects of statins have assayed a narrow array of variables and have focused on cell lines, rodent models, or patient cohorts. We sought to define the effect of rosuvastatin on the ‘immunome’ of healthy, normocholesterolemic subjects. Methods: Prospective study of rosuvastatin (20 mg/day x 28 days) in 18 statin-naïve adults with low density lipoprotein-cholesterol <130 mg/dL. A panel of >180 immune/biochemical/endocrinologic variables was measured at baseline, and days 14, 28, and 42 (14 days after drug withdrawal). Drug effect was evaluated using linear mixed effects models. Potential interactions between drug and baseline high-sensitivity C-reactive protein (hsCRP) were evaluated. Results: A wide array of immune measures changed (nominal p<0.05) during rosuvastatin treatment, although the changes were modest in magnitude and few met a false discovery rate of 0.05. Among changes noted were a concordant increase in pro-inflammatory cytokines (IFNγ, IL-1β, IL-5, IL-6, TNFα) and peripheral blood neutrophil frequency, and a decline in activated T regulatory cell frequency. Several drug effects were significantly modified by baseline hsCRP, and some did not resolve after drug withdrawal. Among other unexpected rosuvastatin effects were changes in erythrocyte indices, glucose-regulatory hormones, CD8+ T cells, and haptoglobin. Conclusion: Rosuvastatin induces modest changes in immunologic and metabolic measures in normocholesterolemic subjects, with several effects dependent upon baseline CRP. Future, larger studies are warranted to validate these changes and their physiological significance.
Authors
Peer W. F. Karmaus, Min Shi, Shira Perl, Angélique Biancotto, Julián Candia, Foo Cheung, Yuri Kotliarov, Neal Young, Michael B. Fessler
Abstract
Severe asthma with fungal sensitization (SAFS) defines a subset of human asthmatics with allergy to one or more fungal species and difficult to control asthma. We have reported that human asthmatics sensitized to fungi have worse lung function and a higher degree of atopy, which was associated with higher IL-1RA levels in bronchoalveolar lavage fluid. IL-1RA further demonstrated a significant negative association with bronchial hyperresponsiveness to methacholine. Here, we show that IL-1α and IL-1β are elevated in both bronchoalveolar lavage fluid and sputum from human asthmatics sensitized to fungi, implicating an association with IL-1α, IL-1β or IL-1RA in fungal asthma severity. In an experimental model of fungal-associated allergic airway inflammation, we demonstrate that IL-1R1 signaling promotes type 1 (IFN-γ, CXCL9, CXCL10) and type 17 (IL-17A, IL-22) responses that were associated with neutrophilic inflammation and increased airway hyperreactivity. Each of these were exacerbated in the absence of IL-1RA. Administration of human recombinant IL-1RA (Kineret/Anakinra) during fungal-associated allergic airway inflammation improved airway hyperreactivity and lowered type 1 and type 17 responses. Taken together, these data suggest that IL-1 receptor signaling contributes to fungal asthma severity via immunopathogenic type 1 and type 17 responses and can be targeted for improving allergic asthma severity.
Authors
Matthew S. Godwin, Kristen M. Reeder, Jaleesa M. Garth, Jonathan P. Blackburn, MaryJane Jones, Zhihong Yu, Sadis Matalon, Annette T. Hastie, Deborah A. Meyers, Chad Steele
Abstract
miR-511-3p, encoded by CD206/Mrc1, was demonstrated to reduce allergic inflammation and promote alternative (M2) macrophage polarization. Here, we sought to elucidate the fundamental mechanism by which miR-511-3p attenuates allergic inflammation and promotes macrophage polarization. Compared with wild-type mice, the allergen-challenged Mrc1-/- mice showed increased airway hyper-responsiveness (AHR) and inflammation. However, this increased AHR and inflammation were significantly attenuated when these mice were pre-transduced with adeno-associated virus (AAV)-miR-511-3p. Gene expression profiling of macrophages identified Ccl2 as one of the major genes that was highly expressed in M2 macrophages but antagonized by miR-511-3p. The interaction between miR-511-3p and Ccl2 was confirmed by in silico analysis and mRNA-miRNA pull-down assay. Further evidence for the inhibition of Ccl2 by miR-511-3p was given by reduced levels of Ccl2 in supernatants of miR-511-3p transduced macrophages and in bronchoalveolar lavage fluids of AAV-miR-511-3p-infected Mrc1-/- mice. Mechanistically, we demonstrated that Ccl2 promotes M1 macrophage polarization by activating RhoA signaling through Ccr2. The interaction between Ccr2 and RhoA was also supported by co-immunoprecipitation assay. Importantly, inhibition of RhoA signaling suppressed cockroach allergen-induced AHR and lung inflammation. These findings suggest a novel mechanism by which miR-511-3p regulates allergic inflammation and macrophage polarization by targeting Ccl2 and its downstream Ccr2/RhoA axis.
Authors
Danh C. Do, Jie Mu, Xia Ke, Karan Sachdeva, Zili Qin, Mei Wan, Faoud T. Ishmael, Peisong Gao
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by pathologic T cell-B cell interactions and autoantibody production. Defining the T cell populations that drive B cell responses in SLE may enable design of therapies that specifically target pathologic cell subsets. Here we evaluated the phenotypes of CD4+ T cells in the circulation of 52 SLE patients drawn from multiple cohorts and identified a highly expanded PD-1hi CXCR5- CD4+ T cell population. Cytometric, transcriptomic, and functional assays demonstrated that PD-1hi CXCR5- CD4+ T cells from SLE patients are T peripheral helper (Tph) cells, a CXCR5- T cell population that stimulates B cell responses via IL-21. The frequency of Tph cells, but not Tfh cells, correlated with both clinical disease activity and the frequency of CD11c+ B cells in SLE patients. PD-1hi CD4+ T cells were found within lupus nephritis kidneys and correlated with B cell numbers in kidney. Both IL-21 neutralization and CRISPR-mediated deletion of MAF abrogated the ability of Tph cells to induce memory B cell differentiation into plasmablasts in vitro. These findings identify Tph cells a highly expanded T cell population in SLE and suggest a key role for Tph cells in stimulating pathologic B cell responses.
Authors
Alexandra V. Bocharnikov, Joshua Keegan, Vanessa S. Wacleche, Ye Cao, Chamith Y. Fonseka, Guoxing Wang, Eric Muise, Kelvin X. Zhang, Arnon Arazi, Gregory Keras, Zhihan J. Li, Yujie Qu, Michael F. Gurish, Michelle Petri, Jill P. Buyon, Chaim Putterman, David Wofsy, Judith A. James, Joel M. Guthridge, Betty Diamond, Jennifer H. Anolik, Matthew F. Mackey, Stephen E. Alves, Peter A. Nigrovic, Karen H. Costenbader, Michael B. Brenner, James A. Lederer, Deepak A. Rao
Abstract
Osteoarthritis (OA) is the leading cause of joint failure, yet the underlying mechanisms remain elusive, and no approved therapies that slow progression exist. Dysregulated integrin function was previously implicated in OA pathogenesis. However, the roles of integrin αVβ3 and the integrin-associated receptor CD47 in OA remain largely unknown. Here, transcriptomic and proteomic analyses of human and murine osteoarthritic tissues revealed dysregulated expression of αVβ3, CD47, and their ligands. Using genetically deficient mice and pharmacologic inhibitors, we showed that αVβ3, CD47, and the downstream signaling molecules Fyn and FAK are crucial to OA pathogenesis. MicroPET/CT imaging of a mouse model showed elevated ligand-binding capacities of integrin αVβ3 and CD47 in osteoarthritic joints. Further, our in vitro studies demonstrated that chondrocyte breakdown products, derived from articular cartilage of individuals with OA, induced αVβ3/CD47-dependent expression of inflammatory and degradative mediators, and revealed the downstream signaling network. Our findings identify a central role for dysregulated αVβ3 and CD47 signaling in OA pathogenesis and suggest that activation of αVβ3 and CD47 signaling in many articular cell types contributes to inflammation and joint destruction in OA. Thus, the data presented here provide a rationale for targeting αVβ3, CD47, and their signaling pathways as a disease-modifying therapy.
Authors
Qian Wang, Kazuhiro Onuma, Changhao Liu, Heidi Wong, Michelle S. Bloom, Eileen E. Elliott, Richard R.L. Cao, Nick Hu, Nithya Lingampalli, Orr Sharpe, Xiaoyan Zhao, Dong Hyun Sohn, Christin M. Lepus, Jeremy Sokolove, Rong Mao, Cecilia T. Cisar, Harini Raghu, Constance R. Chu, Nicholas J. Giori, Stephen B. Willingham, Susan S. Prohaska, Zhen Cheng, Irving L. Weissman, William H. Robinson
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