Biology subjects

DuPage, M.

Publications and source records attributed to DuPage, M..

9 recordsLinked to original sources

bioRxiv2025

MAIT cells induced by engineered Listeria exhibit antibacterial and antitumor activity

Mucosal-associated invariant T (MAIT) cells are among the most conserved and abundant innate-like T cells in humans that recognize microbial-derived riboflavin precursors and elicit potent antimicrobial responses. The foodborne pathogen Listeria monocytogenes is a broad host-range facultative intracellular pathogen that lacks the riboflavin biosynthetic pathway, leading us to hypothesize that this deficiency is pathoadaptive and allows the pathogen to evade MAIT cells. Here, we show that L. monocytogenes strains engineered to produce riboflavin (L. monocytogenes-ribDEAHT) are attenuated in wild-type mice but fully virulent in MAIT cell-deficient mice. Infection with L. monocytogenes-ribDEAHT prompted rapid and robust MAIT cell expansion in multiple tissues and required the cytolytic effector perforin to eliminate infected cells in vivo and in vitro. We also assessed the therapeutic potential of L. monocytogenes-ribDEAHT-stimulated MAIT cells in both infectious disease and cancer mouse models. Therapeutic administration of L. monocytogenes-ribDEAHT provided protection against Francisella tularensis in the lungs and inhibited tumor growth even in the absence of CD8+ T cells. These findings reveal the importance of MAIT cell evasion during L. monocytogenes infection and highlight the therapeutic potential of engineered L. monocytogenes to activate and harness MAIT cells for protection against infectious disease and cancer. Significance StatementListeria monocytogenes is a bacterial pathogen that grows freely in the environment but can become intracellular following ingestion of contaminated food. Although L. monocytogenes can synthesize most metabolites required for growth, it lacks the genes necessary to produce riboflavin (vitamin B2), an essential cofactor across all domains of life. We hypothesized that lacking riboflavin biosynthesis allows L. monocytogenes to evade mucosal-associated invariant T cells (MAIT cells), which generate potent antimicrobial responses against riboflavin-producing microbes. By engineering L. monocytogenes to produce riboflavin, we show that these strains robustly activate MAIT cells and are highly attenuated in wild-type mice, but not in MAIT cell-deficient mice. Furthermore, MAIT cells activated by engineered L. monocytogenes provided therapeutic protection against other riboflavin-producing bacteria and cancer.

microbiology↗

bioRxiv2025

Epigenetically regulated p53 activity maintains intestinal regulatory T cell identity to prevent inflammation

Regulatory T cells (Tregs) are critical guardians of immune homeostasis that must operate in diverse and often inflammatory conditions. However, the mechanisms that Tregs use to maintain their stability and function, especially in response to the stresses of distinct microenvironments, remain incompletely understood. Previous work identified the repressive chromatin modification histone 3 lysine 27 trimethylation (H3K27me3) as a rheostat for Treg function. Here, we find that loss of H3K27me3 in Tregs activates the tumor suppressor p53. Stabilization of p53 using the MDM2 inhibitor Nutlin-3 protected Tregs from losing their master transcription factor Foxp3 in vitro when cultured with the Th17 cytokines IL-6 and IL-1{beta}, while p53 deficiency rendered Tregs more prone to Foxp3 loss. Treg-specific p53 deficiency resulted in accumulation of cells that had lost Foxp3 expression ("ex-Tregs") and reduction of suppressive markers on Tregs specifically in the colon. Additionally, these mice exhibited inflammation in the colon at homeostasis and increased severity of induced colitis. These results demonstrate a specific role for p53 in the maintenance of Treg stability in Th17-polarizing environments and present a possible target for improving Treg-based immunotherapies for diseases defined by intestinal inflammation, such as inflammatory bowel disease (IBD).

immunology↗

bioRxiv2025

Selective disruption of lipid peroxide homeostasis in intratumoral regulatory T cells by targeting FSP1 enhances cancer immunity

A burgeoning approach to treat cancer is the pharmacological induction of ferroptotic cell death of tumor cells. However, the impact of disrupting anti-ferroptotic pathways in the broader tumor microenvironment (TME), such as in immune cells, is still undefined and may complicate treatments. Here, we show that Ferroptosis Suppressor Protein 1 (FSP1/Aifm2) is critically required for regulatory T cell (Treg) resistance to ferroptosis and their immunosuppressive function within the TME. Compared to other canonical ferroptosis regulators such as GPX4, GCH1, and NRF2, only FSP1 was induced upon T cell activation. Deletion of Aifm2 in all T cells, or Tregs specifically, enhanced tumor control by selectively disrupting Treg immunosuppression within tumors without inciting autoimmune pathology in mice. As opposed to deletion of Gpx4 in all T cells, T cell deletion of Aifm2 did not impair antigen-specific CD8+ T cell responses. These results reveal a unique opportunity for targeting a regulator of ferroptosis that can not only directly target cancer cells, but also simultaneously enhance anti-cancer immune responses without inciting autoimmunity.

immunology↗

bioRxiv2025

Intratumoral Treg ablation is sufficient to mediate tumor control systemically without autoimmunity

Regulatory T cells (Tregs) infiltrate most tumors, yet whether they suppress immune responses directly within tumor tissues is not clear. We used intratumoral (IT) delivery of diphtheria toxin (DT) in Foxp3DTR mice to deplete IT Tregs while leaving peripheral Tregs intact. IT delivery of DT reduced Treg frequencies in the tumor, which promoted potent tumor control without autoimmunity. Interestingly, this control was principally mediated by CD4+ T cells, whereas CD8+ T cells only contributed when CD4+ T cells were absent. While conventional dendritic cells (cDCs) were required to clear tumors, Batf3+ cDC1s were dispensable. Distant secondary tumors, mimicking metastases, were also controlled by IT Treg ablation. Mechanistically, IT Tregs suppressed antitumor T cell responses by blocking the acquisition of tumor antigen by cDC2s. Importantly, similar mechanisms of control were observed using a clinically translatable IT Treg-depleting anti-CCR8 antibody and reveal a distinct therapeutic strategy that leverages cDC2s and CD4+ T cells.

cancer biology↗

bioRxiv2025

TLR2 signaling uniquely destabilizes tumor Tregs to promote cancer immunotherapy

A fundamental principle of immune responses is that innate immunity promotes adaptive immunity, but in the context of cancer immunity, the importance of innate receptor signaling is poorly defined. To study how Toll-like receptor (TLR) signaling contributes to cancer immunity, we used an attenuated strain of Listeria monocytogenes (Lm) that inhibits tumor growth in mice. We found that Lm stimulation of TLR2, but not TLR5 or TLR9, was essential for tumor control. As expected, TLR2 supported the priming of Lm-specific T cells in lymphoid tissues. However, TLR2 signaling in innate immune cells within tumors also destabilized Foxp3 expression in regulatory T cells (Tregs), a function that was not mediated by other TLRs. Reduced Treg function promoted tumor antigen cross-presentation by DC1s to enhance the functionality of recalled tumor-specific CD8+ T cells directly within tumors. These findings reveal a unique capacity for TLR2 signaling to diminish immunosuppression and promote cancer immunity.

immunology↗

bioRxiv2025

Intra-Tumoral Treg Ablation Unleashes NK Cell-Mediated Control of CD8 T Cell-Resistant Tumors

Cancer cells frequently lose MHC I to evade CD8+ T cell recognition. While Natural Killer (NK) cells are poised to target MHC I-deficient cancer cells, MHC I loss alone is often insufficient to unleash fully effective NK cell responses. Here we show that selective intra-tumoral (IT) ablation of regulatory T (Treg) cells elicited potent antitumor NK cell responses that controlled MHC I-deficient and even MHC I+ cancers. Tregs controlled the activation, maturation, and anti-tumor cytotoxic activity of NK cells within the tumor microenvironment. Mechanistically, IT Tregs prevented the cDC2-dependent induction of IL-2 production by CD4+ Tconv cells that was necessary for NK cell activation. Systemically administered antibodies that selectively depleted IT Tregs similarly empowered NK- dependent tumor control. These findings expand the breadth of Treg-mediated cancer immunosuppression to encompass antitumor NK cells and suggest that targeting Tregs in tumors can control CD8+ T cell-resistant cancers. One Sentence SummaryIT Treg ablation drives NK cell tumor control via CD4+ Tconv-derived IL-2, eliminating MHC I+/MHC I- cancers without systemic toxicity.

immunology↗

bioRxiv2024

Increased EZH2 function in regulatory T cells promotes their capacity to suppress autoimmunity by driving effector differentiation prior to activation

The immunosuppressive function of regulatory T (Treg) cells is essential for maintaining immune homeostasis. Enhancer of zeste homolog 2 (EZH2), a histone H3 lysine 27 (H3K27) methyltransferase, plays a key role in maintaining Treg cell function upon CD28 co-stimulation, and Ezh2 deletion in Treg cells causes autoimmunity. Here we assessed whether increased EZH2 activity in Treg cells would improve Treg cell function. Using an Ezh2 gain-of-function mutation, Ezh2Y641F, we found that Treg cells expressing Ezh2Y641F displayed an increased effector Treg phenotype and were poised for improved homing to organ tissues. Expression of Ezh2Y641F in Treg cells led to more rapid remission from autoimmunity. H3K27me3 profiling and transcriptomic analysis revealed a redistribution of H3K27me3, which prompted a gene expression profile in naive Ezh2Y641F Treg cells that recapitulated aspects of CD28-activated Ezh2WT Treg cells. Altogether, increased EZH2 activity promotes the differentiation of effector Treg cells that can better suppress autoimmunity. HighlightsO_LIEZH2 function promotes effector differentiation of Treg cells. C_LIO_LIEZH2 function promotes Treg cell migration to organ tissues. C_LIO_LIEZH2 function in Treg cells improves remission from autoimmunity. C_LIO_LIEZH2 function poises naive Treg cells to adopt a CD28-activated phenotype. C_LI

immunology↗

bioRxiv2024

Cellular mechanisms underlying beneficial versus detrimental effects of bacterial antitumor immunotherapy

Bacteria engineered to express tumor antigens as a cancer vaccine have yielded mixed results. Here, we utilized an attenuated strain of Listeria monocytogenes ({Delta}actA, Lm) that does not express tumor antigen to explore the immunological response to Listeria itself in the context of intravenous (IV), intratumoral (IT), or a combination of IV+IT administration into tumor-bearing mice. Unexpectedly, we found that Lm persisted in tumors of immune competent mice, regardless of the administration route. While IT Lm alone led to the recruitment of immunosuppressive immune cells that promoted tumor growth, IV Lm followed by IT Lm controlled tumor growth. IV Lm vaccination generated a pool of anti-Lm cytotoxic CD8 T cells that killed Lm-infected non-tumor cells to control tumor growth both indirectly, by limiting cancer cell proliferation, and directly, by enhancing tumor-specific T cell responses. Our findings reveal a differential impact of IT Lm administration on tumor progression that depends on the presence of anti-Lm CD8 T cells, which alone are sufficient to promote therapeutic efficacy.

immunology↗

bioRxiv2024

A mass cytometry approach to track the evolution of T cell responses during infection and immunotherapy by paired T cell receptor repertoire and T cell differentiation state analysis

T cell receptor (TCR) recognition followed by clonal expansion is a fundamental feature of adaptive immune responses. Here, we developed a mass cytometric (CyTOF) approach combining antibodies specific for different TCR V- and V{beta}-chains with antibodies against T cell activation and differentiation proteins to identify antigen-specific expansions of T cell subsets and assess aspects of cellular function. This strategy allowed for the identification of expansions of specific V{beta} and V chain expressing CD8+ and CD4+ T cells with varying differentiation states in response to Listeria monocytogenes, tumors, and respiratory influenza infection. Expanded V{beta} chain expressing T cells could be directly linked to the recognition of specific antigens from Listeria, tumor cells, or influenza. In the setting of influenza infection, we showed that the common therapeutic approaches of intramuscular vaccination or convalescent serum transfer altered the clonal diversity and differentiation state of responding T cells. Thus, we present a new method to monitor broad changes in TCR specificity paired with T cell differentiation during adaptive immune responses.

immunology↗