Autoimmune disease has presented an insurmountable barrier to restoration of durable immune tolerance. Previous studies indicate that chronic therapy with metabolic inhibitors can reduce autoimmune inflammation, but it remains unknown whether acute metabolic modulation enables permanent immune tolerance to be established. In an animal model of lupus, we determined that targeting glucose metabolism with 2-deoxyglucose (2DG) and mitochondrial metabolism with metformin enables endogenous immune tolerance mechanisms to respond to tolerance induction. A 2-week course of 2DG and metformin, when combined with tolerance-inducing therapy anti-CD45RB, prevented renal deposition of autoantibodies for 6 months after initial treatment and also restored tolerance induction to allografts in lupus-prone mice. The restoration of durable immune tolerance was linked to changes in T cell surface glycosylation patterns, illustrating a role for glycoregulation in immune tolerance. These findings indicate that metabolic therapy may be applied as a powerful preconditioning to reinvigorate tolerance mechanisms in autoimmune and transplant settings that resist current immune therapies.
Christopher S. Wilson, Blair T. Stocks, Emilee M. Hoopes, Jillian P. Rhoads, Kelsey L. McNew, Amy S. Major, Daniel J. Moore
Allogeneic hematopoietic stem cell transplantation is a viable treatment for multiple hematologic diseases, but its application is often limited by graft-versus-host disease (GVHD), where donor T cells attack host tissues in the skin, liver, and gastrointestinal tract. Here, we examined the role of the cellular energy sensor AMP kinase (AMPK) in alloreactive T cells during GVHD development. Early posttransplant, AMPK activity increased more than 15-fold in allogeneic T cells, and transplantation of T cells deficient in both AMPKα1 and AMPKα2 decreased GVHD severity in multiple disease models. Importantly, a lack of AMPK lessened GVHD without compromising antileukemia responses or impairing lymphopenia-driven immune reconstitution. Mechanistically, absence of AMPK decreased both CD4+ and CD8+ effector T cell numbers as early as day 3 posttransplant, while simultaneously increasing regulatory T cell (Treg) percentages. Improvements in GVHD resulted from cell-intrinsic perturbations in conventional effector T cells as depletion of donor Tregs had minimal impact on AMPK-related improvements. Together, these results highlight a specific role for AMPK in allogeneic effector T cells early posttransplant and suggest that AMPK inhibition may be an innovative approach to mitigate GVHD while preserving graft-versus-leukemia responses and maintaining robust immune reconstitution.
Darlene A. Monlish, Kevin J. Beezhold, Pailin Chiaranunt, Katelyn Paz, Nathan J. Moore, Andrea K. Dobbs, Rebecca A. Brown, John A. Ozolek, Bruce R. Blazar, Craig A. Byersdorfer
Diagnosis of organ transplant rejection relies upon biopsy approaches to confirm alloreactive T cell infiltration in the graft. Immune molecular monitoring is under investigation to screen for rejection, though these techniques have suffered from low specificity and lack of spatial information. ImmunoPET utilizing antibodies conjugated to radioisotopes has the potential to improve early and accurate detection of graft rejection. ImmunoPET is capable of noninvasively visualizing the dynamic distribution of cells expressing specific immune markers in the entire body over time. In this work, we identify and characterize OX40 as a surrogate biomarker for alloreactive T cells in organ transplant rejection and monitor its expression by utilizing immunoPET. In a dual murine heart transplant model that has both syngeneic and allogeneic hearts engrafted in bilateral ear pinna on the recipients, OX40 immunoPET clearly depicted alloreactive T cells in the allograft and draining lymph node that were not observed in their respective isograft counterparts. OX40 immunoPET signals also reflected the subject’s immunosuppression level with tacrolimus in this study. OX40 immunoPET is a promising approach that may bridge molecular monitoring and morphological assessment for improved transplant rejection diagnosis.
Toshihito Hirai, Aaron T. Mayer, Tomomi W. Nobashi, Po-Yu Lin, Zunyu Xiao, Tomokatsu Udagawa, Kinya Seo, Federico Simonetta, Jeanette Baker, Alan G. Cheng, Robert S. Negrin, Sanjiv S. Gambhir
Heart transplantation is the optimal therapy for patients with end-stage heart disease, but its long-term outcome remains inadequate. Recent studies have highlighted the importance of the melanocortin receptors (MCRs) in inflammation, but how MCRs regulate the balance between alloreactive T cells and Tregs, and whether they impact chronic heart transplant rejection, is unknown. Here, we found that Tregs express MC2R, and MC2R expression was highest among all MCRs by Tregs. Our data indicate that adrenocorticotropic hormone (ACTH), the sole ligand for MC2R, promoted the formation of Tregs by increasing the expression of IL-2Rα (CD25) in CD4+ T cells and activation of STAT5 in CD4+CD25+ T cells. ACTH treatment also improved the survival of heart allografts and increased the formation of Tregs in CD28KO mice. ACTH treatment synergized with the tolerogenic effect of CTLA-4–Ig, resulting in long-term survival of heart allografts and an increase in intragraft Tregs. ACTH administration also demonstrated higher prolongation of heart allograft survival in transgenic mouse recipients with both complete KO and conditional KO of PI3Kγ in T cells. Finally, ACTH treatment reduced chronic rejection markedly. These data demonstrate that ACTH treatment improved heart transplant outcomes, and this effect correlated with an increase in Tregs.
Jing Zhao, Liwei Jiang, Mayuko Uehara, Naima Banouni, Basmah S. Al Dulaijan, Jamil Azzi, Takaharu Ichimura, Xiaofei Li, Petr Jarolim, Paolo Fiorina, Stefan G. Tullius, Joren C. Madsen, Vivek Kasinath, Reza Abdi
Antibody-mediated rejection (ABMR) continues to be a major problem undermining the success of kidney transplantation. Acute antibody-mediated rejection (ABMR) of kidney grafts is characterized by neutrophil and monocyte margination in the tubular capillaries and by graft transcripts indicating NK cell activation, but the myeloid cell mechanisms required for acute ABMR have remained unclear. Dysregulated donor-specific antibody (DSA) responses with high antibody titers are induced in B6.CCR5-/- mice transplanted with complete MHC mismatched A/J kidneys and are required for rejection of the grafts. This study tested the role of recipient myeloid cell production of myeloperoxidase (MPO) on the cellular and molecular components of acute ABMR. Despite induction of equivalent DSA titers, B6.CCR5-/- recipients rejected A/J kidneys between days 18-25 with acute ABMR whereas B6.CCR5-/-MPO-/- recipients rejected the grafts between days 46-54 with histopathological features of chronic graft injury. On day 15, myeloid cells infiltrating grafts from B6.CCR5-/- and B6.CCR5-/-MPO-/- recipients expressed marked phenotypic and functional transcript differences that correlated with development of acute vs. chronic allograft injury, respectively. Near the time of peak DSA titers, NK cell activation to proliferate and express CD107a was markedly decreased within allografts in B6.CCR5-/-MPO-/- recipients. Despite high titers of DSA, depletion of neutrophils reproduced the inhibition of NK cell activation and decreased macrophage infiltration but increased monocytes producing MPO. Overall, recipient myeloid cells producing MPO regulate graft-infiltrating monocyte/macrophage function and NK cell activation that are required for DSA-mediated acute kidney allograft injury and their absence switches DSA-mediated acute pathology and graft outcomes to chronic ABMR.
Satoshi Miyairi, Daisuke Ueda, Takafumi Yagisawa, Daigo Okada, Karen S. Keslar, Kazunari Tanabe, Nina Dvorina, Anna Valujskikh, William Baldwin 3rd, Stanley L. Hazen, Robert L. Fairchild
Alloimmune responses driven by donor-specific antibodies (DSAs) can lead to antibody-mediated rejection (ABMR) in organ transplantation. Yet, the cellular states underlying alloreactive B cell responses and the molecular components controlling them remain unclear. Using high dimensional profiling of B cells in a cohort of 96 kidney transplant recipients, we identified expanded numbers of CD27+CD21- activated memory (AM) B cells that expressed the transcription factor T-bet in patients who developed DSAs and progressed to ABMR. Notably, AM cells were less frequent in DSA+ABMR- patients and at baseline levels in DSA- patients. RNA-seq analysis of AM cells in patients undergoing ABMR revealed these cells to be poised for plasma cell differentiation and to express restricted IGHV sequences reflective of clonal expansion. In addition to T-bet, AM cells manifested elevated expression of IRF4 and Blimp1, and upon co-culture with autologous T follicular helper cells, differentiated into DSA-producing plasma cells in an IL-21 dependent manner. The frequency of AM cells was correlated with the timing and severity of ABMR manifestations. Importantly, T-bet+ AM cells were detected within kidney allografts along with their restricted IGHV sequences. This study delineates a pivotal role for AM cells in promoting humoral responses and ABMR in organ transplantation and highlights them as important therapeutic targets.
Kevin Louis, Elodie Bailly, Camila Macedo, Louis Lau, Bala Ramaswami, Alexander Chang, Uma Chandran, Douglas Landsittel, Xinyan Gu, Geetha Chalasani, Adriana Zeevi, Parmjeet Randhawa, Harinder Singh, Carmen Lefaucheur, Diana Metes
Primary Graft Dysfunction (PGD) is the predominant cause of early graft loss following lung transplantation. We recently demonstrated that donor pulmonary intravascular non-classical monocytes (NCM) initiate neutrophil recruitment. Simultaneously, host-origin classical monocytes (CM) permeabilize the vascular endothelium to allow neutrophil extravasation necessary for PGD. Here, we show that a CCL2-CCR2 axis is necessary for CM recruitment. Surprisingly, although intravital imaging and multichannel flowcytometry revealed that depletion of donor NCM abrogated CM recruitment, single-cell RNA-seq identified donor alveolar macrophages (AM) as predominant CCL2 secretors. Unbiased transcriptomic analysis of murine tissues combined with murine knockouts and chimeras indicated that IL1β production by donor NCM was responsible for the early activation of AM and CCL2 release. IL1β production by NCM was NLRP3 inflammasome-dependent and inhibited by treatment with a clinically approved sulphonylurea. Production of CCL2 in the donor AM occurred through IL1R-dependent activation of the PKC and NFκB-pathway. Accordingly, we show that IL1β-dependent paracrine interaction between donor NCM and AM leads to recruitment of recipient CM necessary for PGD. Since depletion of donor NCM, IL1β or IL1R antagonism, and inflammasome inhibition, abrogated recruitment of CM as well as PGD, and are feasible using FDA-approved compounds, our findings may have potential for clinical translation.
Chitaru Kurihara, Emilia Lecuona, Qiang Wu, Wenbin Yang, Felix L. Nunez-Santana, Mahzad Akbarpour, Xianpeng Liu, Ziyou Ren, Wenjun Li, Melissa Querrey, Sowmya Ravi, Megan L. Anderson, Emily Cerier, Haiying Sun, Megan E. Kelly, Hiam Abdala-Valencia, Ali Shilatifard, Thalachallour Mohanakumar, G.R. Scott Budinger, Daniel Kreisel, Ankit Bharat
Altered inflammation and tissue remodeling are cardinal features of cardiovascular disease and cardiac transplant rejection. Neutrophils have increasingly been understood to play a critical role in acute rejection and early allograft failure; however, discrete mechanisms that drive this damage remain poorly understood. Herein, we demonstrate that early acute cardiac rejection increases allograft prolyl endopeptidase (PE) in association with de novo production of the neutrophil pro-inflammatory matrikine proline-glycine-proline (PGP). In a heterotopic murine heart transplant model, PGP production and PE activity were associated with early neutrophil allograft invasion and allograft failure. Pharmacologic inhibition of PE with Z-Pro-Prolinal reduced PGP, attenuated early neutrophil graft invasion, and reduced pro-inflammatory cytokine expression. Importantly, these changes helped preserve allograft rejection-free survival and function. Notably, within two independent patient cohorts, both PGP and PE activity were increased among patients with biopsy-proven rejection. The observed induction of PE and matrikine generation provides a novel link between neutrophilic inflammation and cardiovascular injury, represents a potentially new target to reduce allogenic immune responses, and uncovers a previously unrecognized mechanism of cardiovascular disease.
Gregory A. Payne, Nirmal S. Sharma, Charitharth V. Lal, Chunyan Song, Lingling Guo, Camilla Margaroli, Liliana Viera, Siva Kumar, Jindong Li, Melanie Bosley, Dongqi Xing, Xin Xu, J. Michael Wells, James F. George, Jose A. Tallaj, Massoud Leesar, J. Edwin Blalock, Amit Gaggar
Graft-versus-host disease (GVHD) is a pathological process caused by an exaggerated donor lymphocyte response to host antigens after allogeneic hematopoietic cell transplantation (allo-HCT). Donor T cells undergo extensive clonal expansion and differentiation, which culminate in damage to recipient target organs. Damage to the gastrointestinal tract is a main contributor to morbidity and mortality. The loss of diversity among intestinal bacteria caused by pretransplant conditioning regimens leads to an outgrowth of opportunistic pathogens and exacerbated GVHD after allo-HCT. Using murine models of allo-HCT, we found that an increase of Bacteroides in the intestinal microbiota of the recipients was associated with reduced GVHD in mice given fecal microbial transplantation. Administration of Bacteroides fragilis through oral gavage increased gut microbiota diversity and beneficial commensal bacteria and significantly ameliorated acute and chronic GVHD development. Preservation of gut integrity following B. fragilis exposure was likely attributed to increased short chain fatty acids, IL-22, and regulatory T cells, which in turn improved gut tight junction integrity and reduced inflammatory cytokine production of pathogenic T cells. The current study provides a proof of concept that a single strain of commensal bacteria can be a safe and effective means to protect gut integrity and ameliorate GVHD after allo-HCT.
M. Hanief Sofi, Yongxia Wu, Taylor Ticer, Steven Schutt, David Bastian, Hee-Jin Choi, Linlu Tian, Corey Mealer, Chen Liu, Caroline Westwater, Kent E. Armeson, Alexander V. Alekseyenko, Xue-Zhong Yu
The aryl-hydrocarbon receptor (AHR) is an intracellular sensor of aromatic hydrocarbons that sits at the top of various immunomodulatory pathways. Here, we present evidence that AHR plays a role in controlling IL-17 responses and the development of pulmonary fibrosis in response to respiratory pathogens following bone marrow transplant (BMT). Mice infected intranasally with gamma-herpesvirus 68 (γHV-68) following BMT displayed elevated levels of the AHR ligand, kynurenine (kyn), in comparison with control mice. Inhibition or genetic ablation of AHR signaling resulted in a significant decrease in IL-17 expression as well as a reduction in lung pathology. Lung CD103+ DCs expressed AHR following BMT, and treatment of induced CD103+ DCs with kyn resulted in altered cytokine production in response to γHV-68. Interestingly, mice deficient in the kyn-producing enzyme indolamine 2-3 dioxygenase showed no differences in cytokine responses to γHV-68 following BMT; however, isolated pulmonary fibroblasts infected with γHV-68 expressed the kyn-producing enzyme tryptophan dioxygenase (TDO2). Our data indicate that alterations in the production of AHR ligands in response to respiratory pathogens following BMT results in a pro-Th17 phenotype that drives lung pathology. We have further identified the TDO2/AHR axis as a potentially novel form of intercellular communication between fibroblasts and DCs that shapes immune responses to respiratory pathogens.
Stephen J. Gurczynski, Nicolas L. Pereira, Steven M. Hrycaj, Carol Wilke, Rachel L. Zemans, Bethany B. Moore
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