Immunology
Abstract
T cells rely on different metabolic pathways to differentiate into effector or memory cells, and metabolic intervention is a promising strategy to optimize T cell function for immunotherapy. Pyruvate dehydrogenase (PDH) is a nexus between glycolytic and mitochondrial metabolism, regulating pyruvate conversion to either lactate or acetyl-CoA. Here, we retrovirally transduced pyruvate dehydrogenase kinase 1 (PDK1) or pyruvate dehydrogenase phosphatase 1 (PDP1), which control PDH activity, into CD8+ T cells to test effects on T cell function. Although PDK1 and PDP1 were expected to influence PDH in opposing directions, by several criteria they induced similar changes relative to control T cells. Seahorse metabolic flux assays showed both groups exhibited increased glycolysis and oxidative phosphorylation. Both groups had improved primary and memory recall responses following infection with murine gammaherpesvirus-68. However, metabolomics using labeled fuels indicated differential usage of key fuels by metabolic pathways. Importantly, CD8+ T cell populations after B cell lymphoma challenge were smaller in both groups, resulting in poorer protection, which was rescued by glutamine and acetate supplementation. Overall, this study indicates that PDK1 and PDP1 both enhance metabolic capacity, but the context of the antigenic challenge significantly influences the consequences for T cell function.
Authors
Taewook Kang, Young-Kwang Usherwood, Julie A. Reisz, Sukrut C. Kamerkar, Rachel Culp-Hill, Owen M. Wilkins, Andreia F. Verissimo, Fred W. Kolling IV, Anton M. Hung, Shawn C. Musial, Pamela C. Rosato, Angelo D’Alessandro, Henry N. Higgs, Edward J. Usherwood
Abstract
Authors
Joshua A. Keefe, Jose Alberto Navarro-Garcia, Shuai Zhao, Mihail G. Chelu, Xander H.T. Wehrens
Abstract
Radiotherapy triggers chemokine release and leukocyte infiltration in pre-clinical models through activation of the senescence-associated secretory phenotype (SASP). However, effects of irradiation on senescence and SASP in human tissue and in the context of particle radiotherapy remain unclear. Here, we analyzed chemokine patterns after radiotherapy of human pancreatic tumors and cancer cell lines. We show that irradiated tumor cells co-express SASP chemokines in defined modules. These chemokine modules correlated with infiltration of distinct leukocyte subtypes expressing cognate receptors. We developed a patient-derived pancreatic tumor explant system, which confirmed our identified radiation-induced chemokine modules. Chemokine modules were partially conserved in cancer cells in response to photon and particle irradiation showing a dose-dependent plateau effect and induced subsequent migration of NK and T cell populations. Hence, our work reveals redundant interactions of cancer cells and immune cells in human tissue, suggesting that targeting multiple chemokines is required to efficiently perturb leukocyte infiltration after photon or particle radiotherapy.
Authors
Joscha A. Kraske, Michael M. Allers, Aleksei Smirnov, Bénédicte Lenoir, Azaz Ahmed, Meggy Suarez-Carmona, Mareike Hampel, Damir Krunic, Alexandra Tietz-Dalfuß, Tizian Beikert, Jonathan M. Schneeweiss, Stephan Brons, Dorothee Albrecht, Thuy Trinh, Muzi Liu, Nathalia A. Giese, Christin Glowa, Jakob Liermann, Ramon Lopez Perez, Dirk Jäger, Jürgen Debus, Niels Halama, Peter E. Huber, Thomas Walle
Abstract
FOXP3+ Treg cells are critical for immune tolerance. Genetic deletion of the Forkhead domain containing proteins of the FOXP-subfamily member FOXP1 from Tregs results in impaired function associated with reduced CD25 expression and IL-2 signaling, but to date the only other FOXP family member expressed in Tregs, FOXP4, has been minimally studied. To investigate the potential functional interactions among FOXP family members in Treg cells, we specifically deleted Foxp1, Foxp4 or both in FOXP3+ committed Treg cells in mice. Our findings show that mice with combined, but not individual, deficiency in FOXP1 and FOXP4 exhibit lymphoproliferation, inflammation, autoimmunity, and early lethality. The combined absence of FOXP1 and FOXP4 in Tregs results in an activated/effector-like phenotype with compromised suppressive function in peripheral lymphoid organs, an enhanced germinal center response and proinflammatory cytokine production. We further show that FOXP1 and FOXP4 bind to Il2ra promoter regions to regulate CD25 expression in Tregs. Through pairwise comparison among mouse strains with Treg specific deletion of Foxp1, Foxp4 or both, our findings indicate a non-redundant but insufficient role of FOXP4 in Treg cell function.
Authors
Dachuan Dong, Vishal J. Sindhava, Ananthakrishnan Ganesan, Martin S. Naradikian, Tom L. Stephen, Andrew Frisch, Kristen M. Valentine, Elizabeth Buza, Karla R. Wiehagen, Michael P. Cancro, Edward E. Morrisey, Haley Tucker, Katrina K. Hoyer, Purvesh Khatri, Jonathan S. Maltzman
Abstract
Exposure to Bacillus Calmette-Guérin (BCG) or Canarypox ALVAC/Alum vaccine elicits pro- or antiinflammatory innate responses, respectively. We tested whether prior exposure of macaques to these immunogens protected against SARS-CoV-2 replication in lungs and found more efficient replication control after the pro-inflammatory immunity elicited by BCG. The decreased virus level in lungs was linked to early infiltrates of classical monocytes producing IL-8 with systemic neutrophils, Th2 cells, and Ki67+CD95+CD4+ T cells producing CCR7. At the time of SARS-CoV-2 exposure, BCG-treated animals had higher frequencies of lung infiltrating neutrophils and higher CD14+ cells expressing efferocytosis marker MERTK, responses correlating with decreased SARS-CoV-2 replication in lung. At the same time point, plasma IL-18, TNF-α, TNFSF-10, and VEGFA levels were also higher in the BCG group and correlated with decreased virus replication. Finally, after SARS-CoV-2 exposure, decreased virus replication correlated with neutrophils producing IL-10 and CCR7 preferentially recruited to the lungs of BCG-vaccinated animals. These data point to the importance of the spatiotemporal distribution of functional monocytes and neutrophils in controlling SARS-CoV-2 levels and suggest a central role of monocyte efferocytosis in curbing replication.
Authors
Mohammad Arif Rahman, Katherine C. Goldfarbmuren, Sarkis Sarkis, Massimiliano Bissa, Anna Gutowska, Luca Schifanella, Ramona Moles, Melvin N. Doster, Hanne Andersen, Yogita Jethmalani, Leonid Serebryannyy, Timothy Cardozo, Mark G. Lewis, Genoveffa Franchini
Abstract
Regulatory T cells (Tregs) are essential for peripheral tolerance and depend on TCR and IL-2R signaling for their homeostasis and function. In mice, IL-2-dependent BLIMP-1 contributes to Treg homeostasis. BLIMP-1 is a major transcriptional hub in human Tregs, but its mechanisms of action remain undefined. Here, using CRISPR/Cas9 ablation, we show that BLIMP-1 limits human Treg proliferation, but supports IL-10, CTLA4, several immune checkpoints, including CEACAM1, and Treg functional activity. BLIMP-1 restrains Treg expansion to IL-2 by downregulating CD25 and IL-2R signaling, and by enhancing CEACAM1 expression, which in turn inhibits responsiveness to CD3/CD28 signaling and activation of mTOR. Prolonged IL-2R signaling optimizes BLIMP-1 expression, supporting chromosomal opening of CEACAM1 to increased CEACAM1 expression through STAT5- and BLIMP-1-driven enhancers. Correspondingly, CEACAM1 is highly induced on Tregs from autoimmune patients undergoing low-dose IL-2 therapy, and these Tregs showed reduced proliferation. A humanized mouse model of xenogeneic graft versus host disease demonstrates that BLIMP-1 normally promotes, while CEACAM1 restrains, Treg suppressive activity. Collectively, our findings reveal that BLIMP-1 and CEACAM1 function in an IL-2-dependent feedback loop to restrain Treg proliferation and affect suppressive function. CEACAM1 also acts as a highly selective biomarker of IL-2R signaling in human T cells.
Authors
Ying Ding, Aixin Yu, Milos Vujanac, Sabrina N. Copsel, Alejandro Moro, Luis Nivelo, Molly Dalzell, Nicolas Tchitchek, Michelle Rosenzwajg, Alejandro V. Villarino, Robert B. Levy, David Klatzmann, Thomas R. Malek
Abstract
Radiation-induced lymphopenia (RIL) remains a challenging side effect of radiation therapy, often associated with poor prognosis and reduced overall survival. Although CD8+ T cells are highly radiosensitive, the dynamics of quantitative and qualitative changes to the CD8 T cell pool following exposure to high doses of ionizing radiation (IR) remains understudied. Herein, we sought to determine the long-term impact of sublethal whole body irradiation (WBI) on antigen (Ag)-inexperienced CD8 T cell pool, comprised of naïve (TN) and virtual memory (TVM) CD8+ T cells. We show that although both TN and TVM cells gradually regenerate after WBI-induced loss, TN recovery only occurs through de novo thymic production. Despite the numerical restoration, the subset and phenotypic composition of post-recovery Ag-inexperienced CD8+ T cells do not qualitatively recapitulate the pre-WBI state. Specifically, the frequency of TVM cells is increased, especially during the early stages of recovery. Within the TN subset, a lasting overrepresentation of Ly6C+CD122+ cells and an altered TCR clonotype diversity are also observed. Overall, our data highlight the dynamic changes to the Ag-inexperienced CD8+ T cell pool upon recovery from RIL.
Authors
Mohammad Heidarian, Shravan K. Kannan, Whitney Swanson, Thomas S. Griffith, John T. Harty, Vladimir P. Badovinac
Abstract
Infections with non-tuberculous mycobacterium (NTM) are on the rise. Here, we investigated an uncommon NTM infection, by M. haemophilum (Mh, n = 3), from a shared geographic location in the USA. All patients had underlying immunosuppressive conditions or treatments. We identified that all these individuals had a non-synonymous mutation in GATA2 gene, which was absent in Healthy controls (HCs, n = 4) from the same geographic area (Missouri, USA). Whole blood from these individuals had attenuated cytokine responses to Mh stimulation for IL1β, IL-6, IL-8, MIP-1α and β, but not to Phytohemagglutinin (PHA) or another NTM, M. abscessus. Impaired whole blood transcriptional responses in individuals with GATA2 mutation, included heightened Ras-homolog (Rho) guanosine triphosphate hydrolases (GTPase) and lowered Transforming growth factor (TGF)-β responses among others. Our results highlight that comparatively, M. abscessus and Mh elicit differential immune responses in humans, and we identify a 23-gene signature that distinguishes host response to Mh and M. abscessus and show that in vitro GATA2 siRNA knockdown indeed attenuates cytokine responses to Mh. Thus, we provide new evidence that links GATA2 mutation and immune dysfunction in individuals with compromised immunity to Mh infection in humans and outline host factors associated with the immune response of this clinically relevant NTM.
Authors
Ananya Gupta, Shail B. Mehta, Abhimanyu A, Bruce A. Rosa, John Martin, Mushtaq Ahmed, Shyamala Thirunavukkarasu, Farheen Fatma, Gaya Amarsinghe, Makedonka Mitreva, Thomas C. Bailey, David B. Clifford, Shabaana A. Khader
Abstract
Reprogramming autoreactive CD4⁺ effector T (Teff) cells into immunosuppressive regulatory T (Treg) cells represents a promising strategy for treating established autoimmune diseases. However, the stability and function of such reprogrammed Tregs under inflammatory conditions remain unclear. Here, we show that epigenetic activation of core Treg identity genes in Teff cells yields lineage-stable Effector T cell Reprogrammed Tregs (ER-Tregs). A single adoptive transfer of ER-Tregs not only prevents autoimmune neuroinflammation in mice when given before disease onset but also arrests its progression when administered after onset. Compared to Foxp3 overexpressing Teff cells, induced Tregs from naïve precursors, and endogenous Tregs, ER Tregs provide superior protection against autoimmune neuroinflammation. This enhanced efficacy stems from their inherited autoantigen specificity and selectively preserved effector cell transcriptional programs, which together bolster their fitness in inflammatory environments and enhance their suppressive capacity. Our results establish epigenetic reprogramming of autoreactive Teff cells as an effective approach to generate potent, stable Tregs for the treatment of refractory autoimmune conditions.
Authors
Tyler R. Colson, James J. Cameron, Hayley I. Muendlein, Mei-An Nolan, Jamie L. Leiriao, James H. Kim, Alexander N. Poltorak, Xudong Li
Abstract
Authors
Veethika Pandey, Heike R. Doeppler, Ligia I. Bastea, Alicia K. Fleming Martinez, Barath Shreeder, Brandy H. Edenfield, Keith L. Knutson, DeLisa Fairweather, Peter Storz
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