Immunology
Abstract
The role of type 1 conventional dendritic cells (cDC1) in tolerance induction to solid organ allografts is unknown and important for strategies that seek to prolong allograft viability. Using a murine model deficient in cDC1s, we report cDC1s are required for donor antigen and costimulation blockade (DST + CoB) tolerance induction and survival of cardiac allografts. cDC1 deficiency led to decreases in CD4+CD25+FoxP3+ T cells within both allograft and spleen tissue of transplant recipients and this was found to be antigen specific. Donor antigen stimulation induced TGF-β1 expression both in vivo cDC1 and in vitro Flt3L derived cDC1. Genetic deletion of Tgfβ1 in cDC1s prevented induction of antigen specific CD4+CD25+FoxP3+ T cells and was associated with cardiac allograft rejection. In parallel, single-cell RNA sequencing and metabolic analysis revealed upregulation of cDC1 mitochondrial metabolic signatures after in vivo exposure to DST + CoB. Genetic inactivation of cDC1 mitochondrial metabolism reduced expression of cDC1 TGF-β1, decreased antigen specific T regulatory cell populations, and impaired allograft tolerance. Taken together, our findings newly implicate cDC1s in strategies to preserve solid organ allografts and also implicate mitochondrial metabolism of cDC1s as a molecular mechanism to enhance the generation of antigen-specific CD4+CD25+FoxP3+ T cells through TGF-β1.
Authors
Samantha L Schroth, Lei Zhang, Rebecca T.L. Jones, Kristofor Glinton, Nikita L. Mani, Hiroyasu Inui, Jesse T. Davidson, Samuel E. Weinberg, Navdeep Chandel, Maria-Luisa Alegre, Edward B. Thorp
Abstract
Chronic inflammatory diseases, like rheumatoid arthritis (RA) have been described to cause central nervous system (CNS) activation. Less is known about environmental factors that enable the CNS to suppress peripheral inflammation in RA. Here, we identified gut microbiota-derived histamine as such factor. We show that low levels of histamine activate the enteric nervous system, increase inhibitory neurotransmitter concentrations in the spinal cord and restore homeostatic microglia, thereby reducing inflammation in the joints. Selective histamine 3 receptor (H3R) signaling in the intestine is critical for this effect, as systemic and intrathecal application did not show effects. Microglia depletion or pharmacological silencing of local nerve fibers impaired oral H3R agonist-induced pro-resolving effects on arthritis. Moreover, therapeutic supplementation of the short-chain fatty acid (SCFA) propionate identified one way to expand local intestinal histamine concentrations in mice and humans. Thus, we define a gut-CNS-joint axis pathway where microbiota-derived histamine initiates the resolution of arthritis via the CNS.
Authors
Kerstin Dürholz, Leona Ehnes, Mathias Linnerbauer, Eva Schmid, Heike Danzer, Michael Hinzpeter-Schmidt, Lena Lößlein, Lena Amend, Michael Frech, Vugar Azizov, Fabian Schälter, Arne Gessner, Sébastien Lucas, Till-Robin Lesker, R. Verena Taudte, Jörg Hofmann, Felix Beyer, Hadar Bootz-Maoz, Yasmin Reich, Hadar Romano, Daniele Mauro, Ruth Beckervordersandforth, Maja Skov Kragsnaes, Torkell Ellingsen, Wei Xiang, Aiden Haghikia, Cezmi A. Akdis, Francesco Ciccia, Tobias Bäuerle, Kerstin Sarter, Till Strowig, Nissan Yissachar, Georg Schett, Veit Rothhammer, Mario M. Zaiss
Abstract
Downregulation of antigen presentation and lack of immune infiltration are defining features of small cell lung cancer (SCLC) limiting response to immune checkpoint blockade (ICB). While a high MHC Class I, immune-inflamed subset benefits from ICB, underlying mechanisms of immune response in SCLC have yet to be elucidated. Here we show that in the landmark IMpower133 clinical trial high, but not low, NOTCH1 expression is significantly associated with longer survival with the addition of ICB to chemotherapy among ~80% of SCLC patients with neuroendocrine-enriched tumors (ASCL1-enriched, HR 0.39, P = 0.0012; NEUROD1-enriched, HR 0.44, P = 0.024). Overexpression or pharmacologic activation of NOTCH1 in ASCL1 and NEUROD1 SCLC cell lines dramatically upregulates MHC Class I through epigenetic reactivation of STING. In syngeneic mouse models, Notch1 activation reprograms SCLC tumors from immune-excluded to immune-inflamed, facilitating durable, complete responses with ICB combined with a STING agonist. STING1 expression is significantly enriched in high compared to low NOTCH1 expressing tumors in IMpower133 thereby validating our proposed mechanism. Our data reveal a previously undiscovered role for NOTCH1 as a critical driver of SCLC immunogenicity and a potential predictive biomarker for ICB in SCLC. NOTCH1 activation may be a therapeutic strategy to unleash anti-tumor immune responses in SCLC and other neuroendocrine cancers in which NOTCH1 is typically suppressed.
Authors
Yoo Sun Kim, Barzin Y. Nabet, Briana N. Cortez, Nai-Yun Sun, Robin Sebastian, Christophe E. Redon, Anagh Ray, Liang Liu, Afeez A. Ishola, Sarah Loew, Anjali Dhall, Sivasish Sindiri, Velimir Gayevskiy, Min-Jung Lee, Shraddha Rastogi, Nahoko Sato, Noemi Kedei, Thorkell Andresson, Sudipto Das, Suresh Kumar, Alan E. Bers, Hongliang Zhang, Alberto Chiappori, Priyanka Gopal, Mohamed E. Abazeed, Haobin Chen, Mirit I. Aladjem, Yves Pommier, Moises J. Velez, David S. Shames, Nitin Roper
Abstract
Group 2 innate lymphoid cells (ILC2s) play a crucial role in inducing type 2 inflammation in the lungs in response to allergens. Our study investigated the regulatory mechanism of IL-10 production by ILC2s and its impact on airway hyperreactivity (AHR), focusing on the role of ICOS. We found that inhibiting ICOS in pulmonary ILC2s significantly enhances IL-10 production. The absence of ICOS reprograms ILC2 steroid metabolism, leading to increased cholesterol and cortisol biosynthesis, and subsequent Glucocorticoid receptor (GR) activation. This reprogramming regulates MAF and NFIL3 activation, promoting IL-10 production. Notably, in vivo GR inhibition or ILC2-specific GR deficiency exacerbated AHR development in multiple mouse models. We extended these findings to human ILC2s, demonstrating concordant results between murine models and human cells. Our results indicate that ICOS negatively regulates IL-10 production in ILC2s by controlling cholesterol and cortisol biosynthesis. This mechanism provides new insights into the complex interplay between ILC2s, ICOS, and glucocorticoid signaling in the context of allergic airway inflammation.
Authors
Yoshihiro Sakano, Kei Sakano, Benjamin P. Hurrell, Mohammad H. Kazemi, Xin Li, Stephen Shen, Omid Akbari
Abstract
Perianal fistulizing Crohn’s disease (PCD) is a common and debilitating complication with elusive pathophysiology. To define actionable immunologic targets in PCD, we recruited patients with PCD (n = 24), CD without perianal disease (NPCD, n = 10), and idiopathic/cryptoglandular perianal fistulas (IPF, n = 29). Biopsies from fistula tracts, fistula opening, and rectal mucosa were analyzed using single-cell RNA-sequencing (scRNA-seq), mass cytometry (CyTOF), and spatial transcriptomics (ST). Global hyperactivation of IFN-g pathways distinguished PCD from idiopathic perianal fistulas and CD without perianal disease in the fistula tracts and/or intestinal mucosa. IFN-g and TNF-a signaling directly induced genes involved in epithelial-to-mesenchymal transition in PCD rectal epithelial cells. Enhanced IFN-g signaling in PCD was driven by pathogenic Th17 (pTh17) cells, which were recruited and activated by myeloid cells overexpressing LPS signature (LPS_myeloid). pTh17 and LPS_myeloid cells co-localized adjacent to PCD fistula tracts on ST and drove local IFN-g signaling. Anti-TNFs facilitated fistula healing by downregulating T and myeloid cell signatures, while promoting mucosal barrier repair and immunoregulatory processes. Key single-cell findings were validated by bulk RNA-seq data of an independent CD cohort. To summarize, we identified IFN-g-driven mechanisms contributing to pathogenesis and highlighted its blockade as a therapeutic strategy for PCD.
Authors
Siyan Cao, Khai M. Nguyen, Kaiming Ma, Tingyi Tan, Xin Yao, Ta-Chiang Liu, Malek Ayoub, Jalpa Devi, Sami Samaan, Yizhou Liu, Radhika Smith, Matthew L. Silviera, Steven R. Hunt, Paul E. Wise, Matthew G. Mutch, Sean C. Glasgow, William C. Chapman Jr, Michelle L. Cowan, Mathew A. Ciorba, Marco Colonna, Parakkal Deepak
Abstract
Gain of plasticity and loss of MHC-II enable tumor cells to evade immune surveillance contributing to tumor development. Here, we showed that the transcriptional corepressor RCOR2 is a key factor that integrates two epigenetic programs surveilling tumor plasticity and immunogenicity. RCOR2 was upregulated predominantly in tumor cells and promoted tumor development in mice through reducing tumor cell death by CD4+/CD8+ T cells and inducing cancer stemness. Mechanistically, RCOR2 repressed RNF43 expression through LSD1-mediated demethylation of histone H3 at lysine 4 to induce activation of Wnt/β-catenin and tumor stemness. Simultaneously, RCOR2 inhibited CIITA expression through HDAC1/2-mediated deacetylation of histone H4 at lysine 16, leading to MHC-II silencing in tumor cells and subsequent impairment of CD4+/CD8+ T cell immunosurveillance, thereby promoting immune evasion. RCOR2 loss potentiated anti-PD-1 therapy in mouse models of cancer and correlated with better response to anti-PD-1 therapy in human patients. Collectively, these findings uncover a “two birds with one stone” effect for RCOR2, highlighting its potential as a valuable target for improved cancer therapy.
Authors
Lei Bao, Ming Zhu, Maowu Luo, Ashwani Kumar, Yan Peng, Chao Xing, Yingfei Wang, Weibo Luo
Abstract
Bloodstream bacterial infections cause one-third of deaths from bacterial infections, and eradication of circulating bacteria is essential to prevent disseminated infections. We here found that hepcidin, the master regulator of systemic iron homeostasis, affected Kupffer cell (KC) immune defense against bloodstream bacterial infections by modulating the gut commensal bacteria-derived tryptophan derivative indole-3-propionic acid (IPA). Hepcidin deficiency impaired bacterial capture by KCs and exacerbated systemic bacterial dissemination through morphological changes in KCs. Gut microbiota depletion and fecal microbiota transplantation revealed that the gut microbiota mediated the alteration of KCs volume. Mechanistically, hepcidin deficiency led to a decreased abundance of the IPA-producing commensal Lactobacillus intestinalis and a concomitant reduction in the gut-to-liver shuttling of its metabolite IPA. IPA supplementation or Lactobacillus intestinalis colonization restored the KC volume and hepatic immune defense against bloodstream bacterial infection in hepcidin-deficient mice. Moreover, hepcidin levels in patients with bacteremia were associated with days of antibiotic usage and hospitalization. Collectively, our findings described a previously unappreciated role of hepcidin in sustaining KC-mediated hepatic defense against bloodstream bacterial infections through the gut commensal Lactobacillus intestinalis and its tryptophan derivative IPA. More importantly, restoring the crosstalk between the gut microbiota and liver through IPA-inspired therapies may offer a promising strategy for enhancing the host defense against bloodstream bacterial infections in those with low hepcidin levels and a high risk for bacterial infections.
Authors
Yihang Pan, Lihua Shen, Zehua Wu, Xueke Wang, Xiwang Liu, Yan Zhang, Qinyu Luo, Sijin Liu, Xiangming Fang, Qiang Shu, Qixing Chen
Abstract
Coinhibitory receptors function as central modulators of the immune response to resolve T effector activation and/or to sustain immune homeostasis. Here, using humanized SCID mice, we found that neuropilin–2 (NRP2) is inducible on late effector and exhausted subsets of human CD4+ T cells and that it is coexpressed with established coinhibitory molecules including PD-1, CTLA4, TIGIT, LAG3, and TIM3. In murine models, we also found that NRP2 is expressed on effector memory CD4+ T cells with an exhausted phenotype and that it functions as a key coinhibitory molecule. Knockout (KO) of NRP2 resulted in hyperactive CD4+ T cell responses and enhanced inflammation in delayed-type hypersensitivity and transplantation models. After cardiac transplantation, allograft rejection and graft failure were accelerated in global as well as CD4+ T cell–specific KO recipients, and enhanced alloimmunity was dependent on NRP2 expression on CD4+ T effectors but not on CD4+Foxp3+ Tregs. Also, KO Tregs were found to be as efficient as WT cells in the suppression of effector responses in vitro and in vivo. These collective findings identify NRP2 as a potentially novel coinhibitory receptor and demonstrate that its expression on CD4+ T effector cells is of great functional importance in immunity.
Authors
Johannes Wedel, Nora Kochupurakkal, Sek Won Kong, Sayantan Bose, Ji-Won Lee, Madeline Maslyar, Bayan Alsairafi, Kayla MacLeod, Kaifeng Liu, Hengcheng Zhang, Masaki Komatsu, Hironao Nakayama, Diane R. Bielenberg, David M. Briscoe
Abstract
Chagas disease, caused by Trypanosoma cruzi, is endemic to Latin America and is characterized by chronic inflammation of cardiac tissues due to parasite persistence. Hypoxia within infected tissues may trigger the stabilization of HIF-1 and be linked to ATP release. Extracellular ATP exhibits microbicidal effects but is scavenged by CD39 and CD73 ectonucleotidases, which ultimately generate adenosine (ADO), a potent immunosuppressor. Here, we comprehensively study the importance of HIF-1 stabilization and the CD39/CD73/ADO axis, on CD4+ T cells with the cytotoxic phenotype, in facilitating the persistence of T. cruzi. Myocardial infection induces prominent areas of hypoxia, which is concomitant with HIF-1α stabilization in T cells and linked to early expansion of CD39+CD73+CD4+ T cell infiltrating population. Functional assays further demonstrate that HIF-1 stabilization and CD73 activity are associated with impaired CD4+ T cell cytotoxic potential. RNA-Seq analysis reveals that HIF-1 and purinergic signaling pathways are overrepresented in cardiac tissues of patients with end-stage Chagas disease. The findings highlight a major effect of purinergic signaling on CD4+ T cells with potential cytotoxic capacity in the setting of T. cruzi infection and have translational implications for therapy.
Authors
Gastón Bergero, Yanina L. Mazzocco, Sebastian Del Rosso, Ruining Liu, Zoé M. Cejas Gallardo, Simon C. Robson, Martin Rottenberg, Maria P. Aoki
Abstract
In preclinical mouse models of triple-negative breast cancer (TNBC), we show that a combination of chemotherapy with cisplatin (CDDP) and eribulin (Eri) was additive from an immunological point of view and was accompanied by the induction of an intratumoral immune and inflammatory response favored by the immunogenic cell death induced by CDDP, as well as by the vascular and tumor stromal remodeling induced by each chemotherapy. Unexpectedly, despite the favorable immune context created by this immunomodulatory chemotherapy combination, our models remained refractory to the addition of anti–PD-L1 immunotherapy. These surprising observations led us to discover that CDDP chemotherapy was simultaneously responsible for the production of TGF-β by several populations of cells present in tumors, which favored the emergence of different subpopulations of immune cells and cancer-associated fibroblasts characterized by immunosuppressive properties. Accordingly, co-treatment with anti–TGF-β restored the immunological synergy between this immunogenic doublet of chemotherapy and anti–PD-L1 in a CD8-dependent manner. Translational studies revealed the unfavorable prognostic effect of the TGF-β pathway on the immune response in human TNBC, as well as the ability of CDDP to induce this cytokine also in human TNBC cell lines, thus highlighting the clinical relevance of targeting TGF-β in the context of human TNBC treated with chemoimmunotherapy.
Authors
Laura Kalfeist, Fanny Ledys, Stacy Petit, Cyriane Poirrier, Samia Kada Mohammed, Loïck Galland, Valentin Derangère, Alis Ilie, David Rageot, Romain Aucagne, Pierre-Simon Bellaye, Caroline Truntzer, Marion Thibaudin, Mickaël Rialland, François Ghiringhelli, Emeric Limagne, Sylvain Ladoire
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)