Biology subjects

Bullock, T. N.

Publications and source records attributed to Bullock, T. N..

6 recordsLinked to original sources

bioRxiv2026

ST2 Signaling Regulates Innate Immune Responses in Kidney Injury

IntroductionInnate immune cells are critical in inflammation, repair, and fibrosis post-kidney injury. Nuclear-cytokine interleukin (IL)-33, which is released upon tissue damage, signals through IL-1-receptor-like-1 (IL1RL1 or ST2), expressed on many immune cells, including macrophages. However, macrophage regulation by IL-33/ST2 is incompletely understood. We hypothesized that ST2 plays a vital role in activating and/or mobilizing myeloid cells and macrophages to sites of injury. MethodsWe performed acute and chronic ischemia-reperfusion injury (IRI) in mice with myeloid cell-specific deletion of ST2 (ST2fl/fl.LysMCre) to examine the role of myeloid cells ST2 expression in renal injury. The structure and function of the kidney were probed using flow cytometry, histology, immunohistochemistry, quantitative gene expression, and biochemical analysis. The invitro efferocytosis assay, RNA Seq, and Seahorse assay were carried out using bone-marrow-derived macrophages ResultsInterestingly, ST2 deletion resulted in attenuated renal pathology in the acute renal IRI model, whereas in chronic IRI, the loss of ST2 exacerbated kidney injury, suggesting a role of ST2 in the resolution of chronic injury. RNA sequencing (RNASeq) analysis of bone-marrow-derived ST2 sufficient and deficient macrophages showed that loss of ST2 downregulated genes involved in oxidative phosphorylation and clearance of dead cells (efferocytosis). Indeed, the ST2-deficient macrophages had reduced phagocytosis activity. Further, Seahorse analysis revealed that ST2-deficient macrophages had compromised mitochondrial metabolism. ConclusionsWe conclude that the IL-33/ST2 axis is essential for regulating macrophage function and contributes to regulating tissue homeostasis following renal injury.

immunology↗

bioRxiv2025

Stereoselective Degradation of Diacylglycerol Kinases Potentiate T cell Activation and Tumor Cell Cytotoxicity

Stereoselective recognition is a powerful means to differentiate selective versus non-specific activity of small molecules in complex biological systems. Here, we disclose stereochemically defined, sulfonyl-triazole inhibitors of the lipid enzyme diacylglycerol kinase-alpha (DGK), a key metabolic checkpoint for T cell effector function. Acute treatment with the covalent DGK inhibitor AHL-7160 recruited endogenous DGK to the plasma membrane in a stereoselective and isozyme-specific manner. The membrane translocation activity of AHL-7160 correlated with blockade of cellular phosphatidic acid production and potentiation of primary T cell-mediated killing of a glioblastoma cell line. Quantitative chemoproteomics revealed Y669 and K411 as sites of AHL-7160 modification on endogenous DGK in cells. Extended treatments resulted in proteasome-dependent and proteome-wide selective degradation of DGK in T cells. Collectively, these findings establish covalent DGK ligands as potent molecular glues with translational potential in immunotherapy.

biochemistry↗

bioRxiv2025

VEGFR2 blockade converts thermally ablative focused ultrasound into a potent driver of T cell-dependent anti-tumor immunity

Thermally ablative focused ultrasound (TFUS) can induce favorable immune signatures in solid tumors but rarely generates durable systemic immunity or enhances checkpoint inhibition. We tested whether combining TFUS with aVEGFR2, which normalizes tumor vasculature and remodels immune cell composition, triggers T cell-dependent immunity and synergizes with checkpoint inhibition. Subtotal TFUS ([~]40% volumetric ablation fraction, matching clinical trial results) was applied to EMT6 tumors in aVEGFR2-treated BALB/c mice. In EMT6 tumors, TFUS or aVEGFR2 alone had no effect on tumor growth, but their combination eradicated 50% of tumors and drove 83% rechallenge rejection, with CD4/CD8 depletion confirming that tumor eradication and rechallenge rejection were T cell-dependent. TFUS + aPD1 yielded modest benefit, whereas triple therapy (TFUS + aVEGFR2 + aPD1) cured 81% of mice and induced durable, T cell-mediated immunity. Thus, VEGFR2 blockade converts clinically relevant TFUS into a potent systemic immunotherapy and, with the addition of checkpoint inhibition, offers a rational approach to combining already-approved therapies for the treatment of solid tumors.

cancer biology↗

bioRxiv2025

Identification and Evaluation of Benzimidazole- Agonists of Innate Immune Receptor NOD2

Emerging evidence has demonstrated the importance of pattern recognition receptors (PRRs), including the nucleotide-binding and oligomerization domain receptor 2 (NOD2), in human health and disease states. NOD2 activation has shown promise with aiding malnutrition recovery, lessening irritable bowel disease (IBD) symptoms, and increasing the efficacy of cancer immunotherapy. Currently, most NOD2 agonists are derivatives or analogs of the endogenous agonist derived from bacterial peptidoglycan, muramyl dipeptide (MDP). These MDP-based agonists can suffer from low oral bioavailability and cause significant adverse side effects. With the goal of broadly improving NOD2 therapeutic interventions, we sought to discover a novel small molecule capable of activating NOD2 by screening a library of total 1917 FDA approved drugs in a phenotypic assay. We identified a class of compounds, benzimidazoles, that act as NOD2 agonists, with the most potent member of this class being nocodazole. Nocodazole activates NOD2 with nanomolar potency and causes the release of cytokines canonically associated with MDP-induced NOD2 activation, suggesting its potential to elicit similar therapeutic immune effects as MDP and potentially offer improved pharmacological properties.

immunology↗

bioRxiv2023

Boiling histotripsy induces dendritic cell activation and acquisition of antigen in tumor draining lymph nodes

BackgroundBoiling histotripsy (BH), a mechanical focused ultrasound ablation strategy, can elicit intriguing signatures of anti-tumor immunity. However, the influence of BH on dendritic cell function is unknown, compromising our ability to optimally combine BH with immunotherapies to control metastatic disease. MethodsBH was applied using a sparse scan (1 mm spacing between sonications) protocol to B16F10-ZsGreen melanoma in bilateral and unilateral settings. Ipsilateral and contralateral tumor growth was measured. Flow cytometry was used to track ZsGreen antigen and assess how BH drives dendritic cell behavior. ResultsBH monotherapy elicited ipsilateral and abscopal tumor control in this highly aggressive model. Tumor antigen presence in immune cells in the tumor-draining lymph nodes (TDLNs) was [~]3-fold greater at 24h after BH, but this abated by 96h. B cells, macrophages, monocytes, granulocytes, and both conventional dendritic cell subsets (i.e. cDC1s and cDC2s) acquired markedly more antigen with BH. BH drove activation of both cDC subsets, with activation being dependent upon tumor antigen acquisition. Our data also suggest that BH-liberated tumor antigen is complexed with damage-associated molecular patterns (DAMPs) and that cDCs do not traffic to the TDLN with antigen. Rather, they acquire antigen as it flows through afferent lymph vessels into the TDLN. ConclusionWhen applied with a sparse scan protocol, BH monotherapy elicits abscopal melanoma control and shapes dendritic cell function through several previously unappreciated mechanisms. These results offer new insight into how to best combine BH with immunotherapies for the treatment of metastatic melanoma. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/552844v2_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@a486d4org.highwire.dtl.DTLVardef@190041forg.highwire.dtl.DTLVardef@1febf36org.highwire.dtl.DTLVardef@1bb7f8f_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2020

Pre-existing intratumoral CD8 T cells substantially contribute to control tumors following therapeutic anti-CD40 and polyI:C based vaccination

BackgroundDendritic cells are potently activated by the synergistic action of CD40 stimulation in conjunction with signaling through toll like receptors, subsequently activating antigen specific T cells. Cancer vaccines targeting the activation of dendritic cells in this manner show promise in murine models and are being developed for human cancer patients. While vaccine efficacy has been established, further investigation is needed to understand the mechanism of tumor control and how vaccination alters tumor infiltrating immune cells. MethodsMice bearing established murine melanoma tumors were vaccinated with agonist anti-CD40, polyI:C, and tumor antigen. Intratumoral T cell numbers, differentiation state, proliferation, and survival were assessed by flow cytometry. T cell effector function was measured both within the tumor and ex vivo by flow cytometry. T cell trafficking was blocked to examine changes to intratumoral T cells present at the time of vaccination. ResultsVaccination led to increased intratumoral T cell numbers and delayed tumor growth. Expansion of T cells and tumor control did not require trafficking of T cells from the periphery. The increase in intratumoral T cells was associated with an acute burst in proliferation but not changes in viability. Intratumoral T cells had lower PD-1 and Eomes expression but were less functional after vaccination on a per cell basis. However, the increased intratumoral T cell numbers yielded increased effector T cells per tumor. ConclusionsPre-infiltrated CD8 T cells are responsive to CD40/TLR-mediated vaccination and sufficient for vaccination to delay tumor growth when additional T cell trafficking is blocked. This indicates that the existing T cell response and intratumoral DC could be critical for vaccination efficacy. This also suggests that circulating T cells may not be an appropriate biomarker for vaccination efficacy.

immunology↗