Immunology
Abstract
Immune cells are constantly exposed to microbiota-derived compounds that can engage innate recognition receptors. How this constitutive stimulation is down-modulated to avoid systemic inflammation and auto-immunity is poorly understood. Here we show that Aryl hydrocarbon Receptor (AhR) deficiency in monocytes unleashes spontaneous cytokine responses in vivo, driven by STING-mediated tonic sensing of microbiota. This effect was specific to monocytes, as mice deficient for AhR specifically in macrophages did not show any dysregulation of tonic cytokine responses. AhR inhibition also increased tonic cytokine production in human monocytes. Finally, in patients with systemic juvenile idiopathic arthritis, low AhR activity in monocytes correlated with elevated cytokine responses. Our findings evidence an essential role for AhR in monocytes in restraining tonic microbiota sensing and in maintaining immune homeostasis.
Authors
Adeline Cros, Alessandra Rigamonti, Alba de Juan, Alice Coillard, Mathilde Rieux-Laucat, Darawan Tabtim-On, Emeline Papillon, Christel Goudot, Alma-Martina Cepika, Romain Banchereau, Virginia Pascual, Marianne Burbage, Burkhard Becher, Elodie Segura
Abstract
The current gold standard for assessing renal pathology in lupus nephritis (LN) is invasive and cannot be serially repeated. To assess if urine can serve as a liquid biopsy for underlying renal pathology, urine obtained from patients with LN at the time of renal biopsy were interrogated for 1,317 proteins, using an aptamer-based proteomic screen. Levels of 57 urine proteins were significantly elevated and correlated with pathology activity index (AI), notably endocapillary hypercellularity, fibrinoid necrosis, and cellular crescents. These included proteins pertaining to leukocyte/podocyte activation, neutrophil activation, endothelial activation, and markers of inflammation/anti-inflammation. In contrast, complement and coagulation cascade proteins, and proteins related to the extracellular matrix (ECM) emerged as the strongest urinary readouts of concurrent renal pathology chonicity index (CI), notably tubular atrophy and interstitial fibrosis. In vitro mechanistic studies revealed that complement proteins C3a and C5a increased the expression of profibrotic ECM proteins in macrophages and proximal tubule epithelial cells. Thus, carefully assembled panels of urinary proteins that are indicative of high renal pathology AI and/or CI may help monitor the status of renal pathology after therapy in patients with LN, in a noninvasive manner, without the need for repeat renal biopsies.
Authors
Ting Zhang, Jessica Castillo, Anto Sam Crosslee Louis Sam Titus, Kamala Vanarsa, Vedant Sharma, Sohan Kureti, Ramesh Saxena, Chandra Mohan
Abstract
Regulatory T-cells (Treg) are critical for maintaining immune homeostasis, and their adoptive transfer can treat murine inflammatory disorders. In patients, Treg therapies have been variably efficacious. Therefore, new strategies to enhance Treg therapeutic efficacy are needed. Treg predominantly depend upon oxidative phosphorylation (OXPHOS) for energy and suppressive function. Fatty acid oxidation (FAO) contributes to Treg OXPHOS and can be important for Treg “effector” differentiation, but FAO activity is inhibited by coordinated activity of isoenzymes acetyl-CoA Carboxylase-1 and -2 (ACC1/2). Here, we show that small molecule inhibition or Treg-specific genetic deletion of ACC1 significantly increases Treg suppressive function in vitro and in mice with established chronic GVHD. ACC1 inhibition skewed Treg towards an “effector” phenotype and enhanced FAO-mediated OXPHOS, mitochondrial function, and mitochondrial fusion. Inhibiting mitochondrial fusion diminished the effect of ACC1 inhibition. Reciprocally, promoting mitochondrial fusion, even in the absence of ACC1 modulation, resulted in a Treg functional and metabolic phenotype similar to ACC1 inhibition, indicating a key role for mitochondrial fusion in Treg suppressive potency. Ex vivo expanded, ACC1 inhibitor treated human Treg similarly augmented suppressor function as observed with murine Treg. Together, these data suggest that ACC1 manipulation may be exploited to modulate Treg function in patients.
Authors
Cameron McDonald-Hyman, Ethan G. Aguilar, Ewoud B. Compeer, Michael C. Zaiken, Stephanie Y. Rhee, Fathima A. Mohamed, Jemma H. Larson, Michael L. Loschi, Christopher Lees, Govindarajan Thangavelu, Margaret L. Sleeth, Kyle D. Smith, Jennifer S. Whangbo, Jerome Ritz, Tim D. Sparwasser, Roddy S. O'Connor, Peter A. Crawford, Jeffrey C. Rathmell, Leslie S. Kean, Robert Zeiser, Keli L. Hippen, Michael L. Dustin, Bruce R. Blazar
Abstract
Checkpoint inhibitors targeting CTLA-4 and PD-1 revolutionized the treatment of cancer patients, but their use is limited by the emergence of immune-related adverse events (irAE). We assessed autoreactive B cell frequencies in the blood of cancer patients before and after treatment with checkpoint inhibitors by testing the reactivity of recombinant antibodies cloned from single B cells. We found that anti-PD-1 and anti-CTLA-4 combination therapy induced the emergence of autoreactive mature naïve B cells, whereas central B-cell tolerance remained functional. In contrast, anti-PD-1 alone did not alter autoreactive B cell counterselection. Anti-CTLA-4 injections in humanized mice also resulted in the production of autoreactive B cells, whereas anti-PD-1 did not. We conclude that CTLA-4 but not PD-1 is required for the removal of developing autoreactive mature naïve B cells and that CTLA-4 blockade broadens the peripheral B cell repertoire which likely contains clones that promote not only irAEs but also anti-tumor responses.
Authors
Elif Çakan, Meng Wang, Yile Dai, Adrien Mirouse, Clarence Rachel Villanueva-Pachas, Delphine Bouis, Joshua M. Boeckers, Ruchi Gera, Sally Yraita, Leslie Clapp, Ana Luisa Perdigoto, Fabien R. Delmotte, Christopher Massad, Antonietta Bacchiocchi, Aaron M. Ring, Yuval Kluger, Harriet M. Kluger, Kevan C. Herold, Eric Meffre
Abstract
Endoplasmic reticulum (ER) stress through IRE1/XBP-1 is implicated in the onset and progression of graft-versus-host disease (GVHD), but the role of ER stress sensor PERK in T-cell allogeneic responses and GVHD remains unexplored. Here, we report that PERK is a key regulator in T-cell allogeneic response and GVHD induction. PERK augments GVHD through increasing Th1 and Th17 population, while reducing Treg differentiation by activating Nrf2 pathway. Genetical deletion or selective inhibition of PERK pharmacologically reduces GVHD while preserving graft-versus-leukemia (GVL) activity. At cellular level, PERK positively regulates CD4+ T-cell pathogenicity, while negatively regulating CD8+ T-cell pathogenicity in the induction of GVHD. At molecular level, PERK interacts with SEL1L and regulates SEL1L expression, leading to augmented T-cell allogeneic responses and GVHD development. In vivo, PERK deficiency in donor T cells alleviate GVHD through ER-associated degradation (ERAD). Furthermore, pharmacological inhibition of PERK with AMG44 significantly suppresses the severity of GVHD induced by murine or human T cells. In summary, our findings validate PERK as a potential therapeutic target for the prevention of GVHD while preserving GVL responses, and uncover the mechanism by which PERK differentially regulates CD4+ versus CD8+ T-cell allogeneic and anti-tumor responses.
Authors
Qiao Cheng, Hee-Jin Choi, Yongxia Wu, Xiaohong Yuan, Allison Pugel, Linlu Tian, Michael Hendrix, Denggang Fu, Reza Alimohammadi, Chen Liu, Xue-Zhong Yu
Abstract
Allergic diseases have reached epidemic proportions globally, calling attention to the need for better treatment and preventive approaches. Herein, we developed allergen-encoding messenger RNA (mRNA) lipid nanoparticle (LNP) strategies for both therapy and prevention of allergic responses. Immunization with allergen-encoded mRNA-LNPs modulated T cell differentiation, inhibiting the generation of T helper type 2 (Th2) and type 17 (Th17) cells upon allergen exposure in experimental asthma models induced by ovalbumin (OVA), and naturally occurring house dust mite (HDM) and the major HDM allergen Der p1. Allergen-specific mRNA-LNP treatment attenuated clinicopathology in both preventive and established allergy models, including reduction in eosinophilia, mucus production, and airway hypersensitivity, while enhancing production of allergen-specific IgG antibodies and maintaining low IgE levels. Additionally, allergen-specific mRNA-LNP vaccines in mice elicited a CD8+CD38+KLRG- T cell response as seen following SARS-CoV-2 mRNA vaccination in human, underscoring a conserved immune mechanism across species, regardless of the mRNA-encoded protein. Notably, mRNA-LNP vaccination in combination with an mTOR inhibitor reduced the CD8+ T cell response without affecting the vaccine-induced anti-allergic effect in the preventive model of asthma. This technology renders allergen-specific mRNA-LNP therapy as a promising approach for prevention and treatment of allergic diseases.
Authors
Yrina Rochman, Michael Kotliar, Andrea M. Klingler, Mark Rochman, Mohamad-Gabriel Alameh, Jilian R. Melamed, Garrett A. Osswald, Julie M. Caldwell, Jennifer M. Felton, Lydia E. Mack, Julie Hargis, Ian P. Lewkowich, Artem Barski, Drew Weissman, Marc E. Rothenberg
Abstract
The immune ecosystem is central to maintaining effective defensive responses. However, it remains largely understudied how immune cells in the peripheral blood interact with circulating tumor cells (CTCs) in metastasis. Here, blood analysis of patients with advanced breast cancer revealed that over 75% of CTC-positive blood specimens contained heterotypic CTC clusters with CD45+ white blood cells (WBCs), which correlates with breast cancer subtypes, racial groups, and decreased survival. CTC-WBC clusters included overrepresented T cells and underrepresented neutrophils. Specifically, a rare subset of CD4 and CD8 double-positive T (DPT) cells was 140-fold enriched in CTC clusters versus their frequency in WBCs. DPT cells shared properties with CD4+ and CD8+ T cells but exhibited unique features of T cell exhaustion and immune suppression. Mechanistically, the integrin heterodimer α4β1, also named very late antigen 4 (VLA-4), in DPT cells and its ligand, VCAM1, in tumor cells are essential mediators of DPT-CTC clusters. Neoadjuvant administration of anti-VLA-4 neutralizing antibodies markedly blocked CTC–DPT clusters, inhibited metastasis, and extended mouse survival. These findings highlight a pivotal role of rare DPT cells in fostering cancer dissemination through CTC clustering. It lays a foundation for developing innovative biomarker-guided therapeutic strategies to prevent and target cancer metastasis.
Authors
David Scholten, Lamiaa El-Shennawy, Yuzhi Jia, Youbin Zhang, Elizabeth Hyun, Carolina Reduzzi, Andrew D. Hoffmann, Hannah F. Almubarak, Fangjia Tong, Nurmaa K. Dashzeveg, Yuanfei Sun, Joshua R. Squires, Janice Lu, Leonidas C. Platanias, Clive H. Wasserfall, William J. Gradishar, Massimo Cristofanilli, Deyu Fang, Huiping Liu
Abstract
FOXP3+ natural regulatory T cells (nTregs) promote resolution of inflammation and repair of epithelial damage following viral pneumonia-induced lung injury, thus representing a cellular therapy for patients with severe viral pneumonia and the acute respiratory distress syndrome (ARDS). Whether in vitro induced Tregs (iTregs), which can be rapidly generated in substantial numbers from conventional T cells, also promote lung recovery is unknown. nTregs require specific DNA methylation patterns maintained by the epigenetic regulator, ubiquitin-like with PHD and RING finger domains 1 (UHRF1). Here, we tested whether iTregs promote recovery following viral pneumonia and whether iTregs require UHRF1 for their pro-recovery function. We found that adoptive transfer of iTregs to mice with influenza virus pneumonia promotes lung recovery and that loss of UHRF1-mediated maintenance DNA methylation in iTregs leads to reduced engraftment and a delayed repair response. Transcriptional and DNA methylation profiling of adoptively transferred UHRF1-deficient iTregs that had trafficked to influenza-injured lungs demonstrated transcriptional instability with gain of effector T cell lineage-defining transcription factors. Strategies to promote the stability of iTregs could be leveraged to further augment their pro-recovery function during viral pneumonia and other causes of severe lung injury.
Authors
Anthony M. Joudi, Jonathan K Gurkan, Qianli Liu, Elizabeth M. Steinert, Manuel A. Torres Acosta, Kathryn A. Helmin, Luisa Morales-Nebreda, Nurbek Mambetsariev, Carla Patricia Reyes Flores, Hiam Abdala-Valencia, Samuel E. Weinberg, Benjamin D. Singer
Abstract
Sustained CD4+ T cell immunity is required for resolution of acute hepatitis C virus (HCV) infection but the response remains poorly characterized. Here, circulating CD4+ T cells with high PD-1 and ICOS co-expression were temporally associated with onset of virus control, seroconversion, and hepatitis in HCV-infected chimpanzees. Co-production of Tfh (IL-21, CXCL13) and Th1 (IFN-γ, TNF) cytokines after stimulation with HCV non-structural proteins demonstrated that the response was predominately Tfh1-like and virus-specific. Transcriptional analysis confirmed a Tfh1 lineage assignment. Effector-related genes such as ADGRG1 (GPR56), ZNF683 (Hobit), and KLRB1 (CD161) were also expressed. HCV-specific PD-1hiICOShi CD4+ Tfh1-like cells were enriched in liver, suggesting the potential for B and CD8+ T cell help at the site of virus replication. Most circulating and intrahepatic PD-1hiICOShi CD4+ Tfh1-like cells did not express CXCR5, and therefore resembled CXCR5-negative CXCL13-positive peripheral helper (Tph) cells that infiltrate tumors and tissues inflamed by autoimmunity. PD-1hiICOShi CD4+ cells also peaked after hepatitis A virus infection, but the response was accelerated by several weeks when compared with HCV infection. The PD-1hiICOShi phenotype, and temporal association between the peak response and ALT, may provide markers to guide human studies of CD4+ T cell immunity against HCV and other hepatotropic viruses.
Authors
Heather Blasczyk, William G. Bremer, Christopher C. Phelps, Yan Zhou, David G. Bowen, Zhaohui Xu, Robert E. Lanford, Naglaa H. Shoukry, Arash Grakoui, Nicole E. Skinner, Christopher M. Walker
Abstract
Molnupiravir is an antiviral medicine that induces lethal copying errors during SARS-CoV-2 RNA replication. Molnupiravir reduced hospitalization in one pivotal trial by 50% and had variable effects on reducing viral RNA levels in three separate trials. We used mathematical models to simulate these trials and closely recapitulated their virologic outcomes. Model simulations suggest lower antiviral potency against pre-omicron SARS-CoV-2 variants than against omicron. We estimate that in vitro assays underestimate in vivo potency 6-7 fold against omicron variants. Our model suggests that because polymerase chain reaction detects molnupiravir mutated variants, the true reduction in non-mutated viral RNA is underestimated by ~0.4 log10 in the two trials conducted while omicron variants dominated. Viral area under the curve estimates differ significantly between non-mutated and mutated viral RNA. Our results reinforce past work suggesting that in vitro assays are unreliable for estimating in vivo antiviral drug potency and suggest that virologic endpoints for respiratory virus clinical trials should be catered to the drug mechanism of action.
Authors
Shadisadat Esmaeili, Katherine Owens, Ugo Avila-Ponce de Leon, Joseph F. Standing, David M. Lowe, Shengyuan Zhang, James A. Watson, William H.K. Schilling, Jessica Wagoner, Stephen J. Polyak, Joshua T. Schiffer
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)