The excessive formation and release of neutrophil extracellular traps (NETs) in sepsis may represent a substantial mechanism contributing to multi-organ damage, which is associated with a poorer prognosis. However, the precise role of NETs in mediating the transition from innate immunity to adaptive immunity during the progression of inflammation and sepsis remains incompletely elucidated. In this study, we provide evidence that, despite a reduction in the number of CD4+ T-cells in the late stage of sepsis, there is a notable upregulation in the proportion of regulatory T-cells (Tregs). Mechanistically, we have identified that NETs can induce metabolic reprogramming of naïve CD4+ T-cells through the Akt-mTOR-SREBP2 pathway, resulting in enhanced cholesterol metabolism, thereby promoting their conversion into Tregs and augmenting their functional capacity. Collectively, our findings highlight the potential therapeutic strategy of targeting intracellular cholesterol normalization for the management of immunosuppressed patients with sepsis.
Yuxin Shi, Dan Wu, Yanghanzhao Wang, Yuwen Shao, Fu Zeng, Di Zhou, Hao Zhang, Changhong Miao
Glucocorticoid synthesis by adrenal glands (AG) is regulated by the hypothalamic-pituitary-adrenal axis (HPA-axis) to facilitate stress responses when the host is exposed to stimuli. Recent studies have implicated macrophages (MФ) as potential steroidogenic regulators, but the molecular mechanisms by which AG MФ exert such influence remain unclear. In this study, we investigated the role of AG MФ in response to cold challenge or atherosclerotic inflammation as physiologic models of acute or chronic stress. Utilizing single-cell RNA sequencing, we observed dynamic AG MФ polarization toward classical activation and lipid-associated phenotypes following acute or chronic stimulation. Among the transcriptional alterations induced in MФ, Triggering Receptor Expressed on Myeloid (Trem2) was highlighted due to its dramatic upregulation following stress. Conditional deletion of MФ Trem2 revealed a protective role for Trem2 in stress responses. Mechanistically, Trem2 deletion led to increased AG MФ death, abolished the TGFβ-producing capacity of AG MФ, and resulted in enhanced glucocorticoid production. In addition, enhanced glucocorticoid production was replicated by blockade of TGFβ signaling. Together, these observations suggest that AG MФ restrict steroidogenesis through Trem2 and TGFβ, which opens potential avenues for immunotherapeutic interventions targeting the innate immune system to resolve stress-related disorders.
Yingzheng Xu, Michael T. Patterson, Bastien Dolfi, Alisha Zhu, Adeline Bertola, Patricia R. Schrank, Alexandre Gallerand, Ainsley E. Kennedy, Hannah Hillman, Lynn Dinh, Sia Shekhar, Samuel Tollison, Tyler D. Bold, Stoyan Ivanov, Jesse W. Williams
Memory T cells are conventionally associated with durable recall responses. In our longitudinal analyses of CD4+ T cell responses to the yellow fever virus (YFV) vaccine by peptide-MHC tetramers, we unexpectedly found CD45RO-CCR7+ virus-specific CD4+ T cells that expanded shortly after vaccination and persisted months to years after immunization. Further phenotypic analyses revealed the presence of stem-cell memory T cells (TSCM) within this subset. In addition, post-vaccine T cells lacking known memory markers and functionally resembling genuine naïve T cells were identified, referred to herein as marker-negative T cells (TMN). Single-cell TCR sequencing detected expanded clonotypes within the TMN subset and identified TMN TCRs shared with memory and effector T cells. Longitudinal tracking of YFV-specific responses over subsequent years revealed superior stability of TMN cells, which correlated with the longevity of the overall tetramer+ population. These findings uncovered additional complexity within the post-immune T cell compartment and implicate TMN cells in durable immune responses.
Yi-Gen Pan, Laurent Bartolo, Ruozhang Xu, Bijal V. Patel, Veronika I. Zarnitsyna, Laura F. Su
Influenza poses a persistent health burden worldwide. To design equitable vaccines effective across all demographics, it is essential to better understand how host factors such as genetic background and aging affect the single-cell immune landscape of influenza infection. Cytometry by time-of-flight (CyTOF) represents a promising technique in this pursuit, but interpreting its large, high-dimensional data remains difficult. We’ve developed a new analytical approach iGATE (in-silico gating annotating training elucidating) based on probabilistic support vector machine classification. By rapidly and accurately “gating” tens of millions of cells in silico into user-defined types, iGATE enabled us to track 25 canonical immune cell types in mouse lung over the course of influenza infection. Applying iGATE to study effects of host genetic background, we show that the lower survival of C57BL/6 mice compared to BALB/c is associated with a more rapid accumulation of inflammatory cell types and decreased IL-10 expression. Further, we demonstrate that the most prominent effect of aging is a defective T-cell response, reducing survival of aged mice. Finally, iGATE reveals that the 25 canonical immune cell types exhibit differential influenza infection susceptibility and replication permissiveness in vivo, but neither property varies with host genotype or aging. Software is available at https://github.com/UmichWenLab/iGATE.
Brett D. Hill, Andrew J. Zak, Sanjeev Raja, Luke F. Bugada, Syed M. Rizvi, Saiful B. Roslan, Hong Nhi Nguyen, Judy Chen, Hui Jiang, Akira Ono, Daniel R. Goldstein, Fei Wen
Dendritic cell inhibitory receptor (DCIR) is a C-type lectin receptor selectively expressed on myeloid cells, including monocytes, macrophage, dendritic cells, and neutrophils. Its role in immune regulation has been implicated in murine models and human genome-wide association studies (GWAS), suggesting defective DCIR function associates with increased susceptibility to autoimmune diseases such as rheumatoid arthritis, lupus and Sjogren’s syndrome. However, little is known about the mechanisms underlying DCIR activation to dampen inflammation. Here, we developed anti-DCIR agonistic antibodies that promote phosphorylation on DCIR’s immune receptor tyrosine-based inhibitory motifs (ITIM) and recruitment of SH2 containing protein tyrosine phosphatase-2 (SHP2) for reducing inflammation. We also explored the inflammation resolution by depleting DCIR+ cells with antibodies. Utilizing a human DCIR knock-in mouse model, we validated the anti-inflammatory properties of the agonistic anti-DCIR antibody in experimental peritonitis and colitis. These findings provide critical evidence for targeting DCIR to develop transformative therapies for inflammatory diseases.
Liang Chen, Suresh Patil, Jeffrey Barbon, James Waire, F. Stephen Laroux, Donna McCarthy, Mishra Pratibha, Suju Zhong, Feng Dong, Karin Orsi, Gunarso Nguyen, Yingli Yang, Nancy Crosbie, Eric Dominguez, Arun Deora, Geertruida Veldman, Susan V. Westmoreland, Liang Jin, Timothy Radstake, Kevin White, Hsi-Ju Wei
Immunosuppression is a common feature of esophageal adenocarcinoma (EAC) and has been linked to poor overall survival (OS). We hypothesized that upstream factors might negatively influence CD3 levels and T-cell activity, thus promoting immunosuppression and worse survival. We used clinical data and patient samples of those who progressed from Barrett’s (BE) to dysplasia to EAC, investigated gene (RNAseq), protein (tissue microarray) expression and performed cell biology studies to delineate a pathway impacting CD3 protein stability that might influence EAC outcome. We show that the loss of both CD3-ε expression and CD3+ T-cell number are correlated with worse OS in EAC. The GRAIL (gene related to anergy in lymphocytes) isoform 1 (GRAIL1), which is the prominent isoform in EACs, degrades (ε, γ, δ) CD3s and inactivates T-cells. In contrast, isoform 2 (GRAIL2), which is reduced in EACs, stabilizes CD3s. Further, GRAIL1 mediated CD3 degradation is facilitated by interferon stimulated gene 15 (ISG15), a ubiquitin-like protein. Consequently, either the overexpression of a ligase-dead GRAIL1, ISG15 knockdown, or the overexpression of a conjugation-defective ISG15-LRAA mutant can increase CD3 levels. Together, we identified that an ISG15→GRAIL1→mutant p53 amplification loop negatively influencing CD3 levels and T-cell activity, thus promoting immunosuppression in EAC.
Dyke P. McEwen, Paramita Ray, Derek J. Nancarrow, Zhuwen Wang, Srimathi Kasturirangan, Saeed Abdullah, Ayushi Balan, Rishi Hoskeri, Dafydd Thomas, Theodore S. Lawrence, David G. Beer, Kiran H. Lagisetty, Dipankar Ray
Redundant tumor microenvironment (TME) immunosuppressive mechanisms and epigenetic maintenance of terminal T cell exhaustion greatly hinder functional antitumor immune responses in chronic lymphocytic leukemia (CLL). Bromodomain and extraterminal (BET) proteins regulate key pathways contributing to CLL pathogenesis and TME interactions, including T cell function and differentiation. Herein, we report that blocking BET protein function alleviates immunosuppressive networks in the CLL TME and repairs inherent CLL T cell defects. The pan-BET inhibitor OPN-51107 reduced exhaustion-associated cell signatures resulting in improved T cell proliferation and effector function in the Eμ-TCL1 splenic TME. Following BET inhibition (BET-i), TME T cells coexpressed significantly fewer inhibitory receptors (IRs) (e.g., PD-1, CD160, CD244, LAG3, VISTA). Complementary results were witnessed in primary CLL cultures, wherein OPN-51107 exerted proinflammatory effects on T cells, regardless of leukemic cell burden. BET-i additionally promotes a progenitor T cell phenotype through reduced expression of transcription factors that maintain terminal differentiation and increased expression of TCF-1, at least in part through altered chromatin accessibility. Moreover, direct T cell effects of BET-i were unmatched by common targeted therapies in CLL. This study demonstrates the immunomodulatory action of BET-i on CLL T cells and supports the inclusion of BET inhibitors in the management of CLL to alleviate terminal T cell dysfunction and potentially enhance tumoricidal T cell activity.
Audrey L. Smith, Sydney A. Skupa, Alexandria P. Eiken, Timothy E. Reznicek, Elizabeth Schmitz, Nolan Williams, Dalia Y. Moore, Christopher R. D’Angelo, Avyakta Kallam, Matthew A. Lunning, R. Gregory Bociek, Julie M. Vose, Eslam Mohamed, Anna R. Mahr, Paul W. Denton, Ben Powell, Gideon Bollag, M. Jordan Rowley, Dalia El-Gamal
Alloreactive memory, unlike naïve, CD8+ T cells resist transplantation tolerance protocols and are a critical barrier to long-term graft acceptance in the clinic. We here show that semi-allogeneic pregnancy successfully reprogrammed memory fetus/graft-specific CD8+ T cells (TFGS) towards hypofunction. Female C57BL/6 mice harboring memory CD8+ T cells generated by the rejection of BALB/c skin grafts and then mated with BALB/c males achieved rates of pregnancy comparable to naive controls. Post-partum fetus/graft-specific CD8+ T cells (TFGS) from skin-sensitized dams upregulated expression of T cell exhaustion (TEX) markers (Tox, Eomes, PD-1, TIGIT, and Lag3). Transcriptional analysis corroborated an enrichment of canonical T exhaustion (TEX) genes in post-partum memory TFGS and additionally, revealed a downregulation of a subset of memory-associated transcripts. Strikingly, pregnancy induced extensive epigenetic modifications of exhaustion- and memory-associated genes in memory TFGS, whereas minimal epigenetic modifications were observed in naive TFGS cells. Finally, post-partum memory TFGS durably expressed the exhaustion-enriched phenotype, and their susceptibility to transplantation tolerance was significantly restored compared to memory TFGS. These findings advance the concept of pregnancy as an epigenetic modulator inducing hypofunction in memory CD8+ T cells that has relevance not only for pregnancy and transplantation tolerance, but also for tumor immunity and chronic infections.
Jared M. Pollard, Grace Hynes, Dengping Yin, Malay Mandal, Fotini Gounari, Maria-Luisa Alegre, Anita S. Chong
Applying advanced molecular profiling together with highly specific targeted therapies offers the possibility to better dissect the mechanisms underlying immune mediated inflammatory diseases such as systemic lupus erythematosus (SLE) in humans. Here we apply a combination of single cell RNA sequencing and T/B cell repertoire analysis to perform an in-depth characterization of molecular changes in the immune-signature upon CD19 CAR T cell-mediated depletion of B cells in SLE patients. The resulting datasets do not only confirm a selective CAR T cell-mediated reset of the B cell response, but simultaneously reveal consequent changes in the transcriptional signature of monocyte and T cell subsets that respond with a profound reduction in type 1 interferon signaling. Our current data thus provide evidence for a causal relationship between the B cell response and the increased interferon signature observed in SLE and additionally demonstrate the usefulness of combining targeted therapies and novel analytic approaches to decipher molecular mechanisms of immune-mediated inflammatory diseases in humans.
Artur Wilhelm, David Chambers, Fabian Müller, Aline Bozec, Ricardo Grieshaber-Bouyer, Thomas Winkler, Dimitrios Mougiakakos, Andreas Mackensen, Georg Schett, Gerhard Krönke
IgA nephropathy (IgAN) represents the main cause of renal failure, while the precise pathogenetic mechanisms have not been fully determined. Herein, we conducted a cross-species single-cell survey on human IgAN and mouse and rat IgAN models to explore the pathogenic programs. Cross-species single-cell RNA sequencing (scRNA-Seq) revealed that the IgAN mesangial cells (MCs) expressed high levels of inflammatory signatures CXCL12, CCL2, CSF1, and IL-34 and specifically interacted with IgAN macrophages via the CXCL12/CXCR4, CSF1/IL-34/CSF1 receptor, and integrin subunit alpha X/integrin subunit alpha M/complement C3 (C3) axes. IgAN macrophages expressed high levels of CXCR4, PDGFB, triggering receptor expressed on myeloid cells 2, TNF, and C3, and the trajectory analysis suggested that these cells derived from the differentiation of infiltrating blood monocytes. Additionally, protein profiling of 21 progression and 28 nonprogression IgAN samples revealed that proteins CXCL12, C3, mannose receptor C-type 1, and CD163 were negatively correlated with estimated glomerular filtration rate (eGFR) value and poor prognosis (30% eGFR as composite end point). Last, a functional experiment revealed that specific blockade of the Cxcl12/Cxcr4 pathway substantially attenuated the glomerulus and tubule inflammatory injury, fibrosis, and renal function decline in the mouse IgAN model. This study provides insights into IgAN progression and may aid in the refinement of IgAN diagnosis and the optimization of treatment strategies.
Xizhao Chen, Tiantian Wang, Lei Chen, Yinghua Zhao, Yiyao Deng, Wanjun Shen, Lin Li, Zhong Yin, Chaoran Zhang, Guangyan Cai, Min Zhang, Xiangmei Chen
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