InVivoMAb anti-mouse CD28

Osteoarthritis (OA) pathogenesis is profoundly influenced by dysregulated immune dynamics, where persistent interleukin-17 (IL-17)/T helper 17 (Th17) cell mediated inflammation coordinates with failed regenerative processes to perpetuate joint destruction. Here, we unveil the role of myeloid-derived suppressor cells (MDSCs) as dual-phase regulators that paradoxically orchestrate both inflammatory escalation and tissue repair in OA progression. Intra-articular administration of MDSCs in OA mice amplified IL-17 dependent inflammatory cascades and chemokine-driven leukocyte recruitment, revealing a context-dependent pro-inflammatory phenotype. Unexpectedly, MDSC depletion failed to attenuate joint damage, implying their indispensable yet multifaceted role in OA pathogenesis. Mechanistically, MDSCs exhibited functional plasticity by upregulating arginase-1 to polarize M2 macrophages, fostering a regenerative niche alongside their inflammatory activity. To resolve this duality, we developed a bio-responsive hydrogel-microsphere system integrating transforming growth factor β1 (TGF-β1) and interleukin-1 β1 antibody (anti-IL-1β) loaded mesoporous silica nanoparticles (MSNs). This spatiotemporally controlled platform selectively suppressed MDSC-mediated Th17 cell expansion while harnessing their intrinsic capacity to drive M2 macrophage polarization and chondrogenesis. The resultant shift from a pro-inflammatory to pro-regenerative microenvironment significantly attenuated cartilage erosion and restored joint integrity in OA models. Our findings redefine MDSCs as bifunctional immune orchestrators in OA and establish precision biomaterial guided immune decoding as a paradigm-shifting therapeutic strategy. By engineering MDSCs plasticity through antagonistic cytokine delivery, this work provides a blueprint for microenvironment remodeling in degenerative joint diseases.

β-adrenergic signaling has been suggested to promote tumor growth, and β-blockers are being evaluated for repurposing for cancer treatment. Here, we identify a β-adrenergic signaling axis involved in metastasis formation. We show that the β-blocker propranolol has strong anti-metastatic activity in multiple murine models, with this effect being completely dependent on CD4 + T cells and independent of NK or CD8 + T cells. We also observe that CD4 + T cells are required for the anti-tumor effect of propranolol in a syngeneic subcutaneous model of colon cancer. Mechanistically, propranolol induces a Th1-polarized and cytotoxic CD4 + T cell response, which requires MHC class II expression by cancer cells for full efficacy. We also report propanolol-driven systemic changes in the monocyte compartment, and upon depletion of monocytes, propranolol loses its anti-tumor effects. Finally, we show that propranolol treatment synergizes with anti-CTLA-4 therapy to further enhance CD4 + T cell infiltration and control metastasis. Thus, we show that β-adrenergic signaling limits CD4 T cell-mediated anti-tumor immunity, highlighting the potential of repurposing β-blockers for cancer treatment.

Tumor necrosis factor (TNF)-induced RIPK1-mediated cell death is implicated in various human diseases. However, the mechanisms RIPK1-mediated cell death is regulated by metabolic processes remain unclear. Here, we identify hexokinase 2 (HK2), a critical regulator of glycolysis, as a suppressor of TNF-induced RIPK1 kinase-dependent cell death through its non-metabolic function. HK2 inhibits RIPK1 kinase activity through constitutively phosphorylation at serine 32 of RIPK1. Inhibition of RIPK1 S32-phosphorylation results in RIPK1 kinase activation and subsequent cell death in response to TNFα stimulation. We further show that HK2 is elevated under pathological conditions including liver ischemia-reperfusion (IR) injury and hepatocellular carcinoma (HCC) via the transcriptional factor HMGA1. Moreover, the upregulation of HK2 in the liver confers protection against liver IR injury mediated by RIPK1 kinase, while depleting HK2 in HCC cells enhances TNFα-induced cell death and synergistically improves the efficacy of anti-PD1 therapy in an HCC model. Thus, the findings reveal a potential therapeutic avenue for RIPK1-related diseases through manipulating HK2 non-metabolic function.

The heart is one of the least regenerative organs in humans, and ischemic heart disease is the leading cause of death worldwide. Understanding the cellular and molecular processes that occur during cardiac wound healing is an essential prerequisite to reducing health burden and improving cardiac function after myocardial tissue damage. Here, by integrating single-cell RNA sequencing with high-resolution spatial transcriptomics, we reconstruct the spatiotemporal dynamics of the fibrotic niches after cardiac injury in adult mice. We reveal a complex multicellular network that regulates cardiac repair, including fibroblast proliferation silencing by Trem2high macrophages to prevent excessive fibrosis. We further discovered a rare population of progenitor-like cardiomyocytes after lesion, promoted by myeloid and lymphoid niche signals. Culturing non-regenerative mouse cardiomyocytes or human heart tissue with these niche factors reactivated progenitor gene expression and cell cycle activity. In summary, this spatiotemporal atlas provides valuable insights into the heterocellular interactions that control cardiac repair.

Regulatory T (Treg) cells, expressing the transcription factor Foxp3, are obligatory gatekeepers of immune responsiveness, yet the mechanisms by which Foxp3 governs the Treg transcriptional network remain incompletely understood. Using a novel chemogenetic system of inducible Foxp3 protein degradation in vivo, we found that while Foxp3 was indispensable for the establishment of transcriptional and functional programs of newly generated Treg cells, Foxp3 loss in mature Treg cells resulted in minimal functional and transcriptional changes under steady state. This resilience of the Foxp3-dependent program in mature Treg cells was acquired over an unexpectedly long timescale; however, in settings of severe inflammation, Foxp3 loss led to a pronounced perturbation of Treg cell transcriptome and fitness. Furthermore, tumoral Treg cells were uniquely sensitive to Foxp3 degradation, which led to impairment in their suppressive function and tumor shrinkage in the absence of pronounced adverse effects. These studies demonstrate a context-dependent differential requirement for Foxp3 for Treg transcriptional and functional programs.

Mechanisms of T cell aging involve cell-intrinsic alterations and interactions with immune and stromal cells. Here we found that splenic T cells exhibit greater functional decline than lymph node T cells within the same aged mouse, prompting investigation into how the aged spleen contributes to T cell aging. Proteomic analysis revealed increased expression of heme detoxification in aged spleen-derived lymphocytes. Exposure to the heme- and iron-rich aged splenic microenvironment induced aging phenotypes in young T cells, including reduced proliferation and CD39 upregulation. T cells survived this hostile niche by maintaining a low labile iron pool, at least in part, via IRP2 downregulation to resist ferroptosis but failed to induce sufficient iron uptake for activation. Iron supplementation enhanced antigen-specific T cell responses in aged mice. This study identifies the aged spleen as a source of hemolytic signals that systemically impair T cell function, underscoring a trade-off between T cell survival and function and implicating iron metabolism in immune aging.

The immune protection of pancreatic β cells has three layers: anatomical, with their distribution in 1 million islets; central, with the thymic deletion of β cell-specific T cells; and peripheral, with inhibitory cellular networks. The failure of the latter leads to most spontaneous type 1 diabetes and all diabetes induced by checkpoint inhibitor therapy. Because CD4 T cells initiate disease, major histocompatibility complex (MHC) class II-expressing cells are central to the onset. In non-diabetic mouse and human islets, two such cells were detected outside of the islet boundaries near the efferent post-capillary venules: one related to the vasculature and a fibroblast referred to as a "vascular-associated fibroblast" (VAF). Functionally, primary VAFs spontaneously presented islet antigens to CD4 T cells and expressed high levels of inhibitory B7 receptors and no costimulatory receptors. VAFs induced anergy in primary pre-activated anti-islet CD4 T cells. VAFs are likely important to protect the endocrine pancreas from autoimmunity.

Neutrophils constitute a substantial proportion of the immune cell population infiltrating tumors, where they play a pivotal role in establishing an immunosuppressive microenvironment to facilitate tumor growth. Our clinical investigation has unveiled that, following oncolytic virus (OV) treatment, immunosuppressive neutrophils could lead to T cell exhaustion and compromised antitumor efficacy. In this study, we devise a dual-functional conjugation strategy that enables OVs to selectively bind with circulating neutrophils and initiate their death. Prior to dysfunction, neutrophils can harbor OVs and facilitate their infiltration into tumors, leading to a 5.38-fold increase in OV levels within tumors compared to direct intravenous injection. Additionally, infiltrated neutrophils undergo dying after 8 h, which promotes T cell priming, reduces T cell exhaustion, and remodels the tumor immune microenvironment. Our findings illuminate the determinants influencing the efficacy of OVs and propose targeted solutions, thereby offering insights for the clinical translation of these therapeutic agents.

Viral infection of cells leads to metabolic changes, but how viral infection changes whole-body and tissue metabolism in vivo has not been comprehensively studied. In particular, it is unknown how metabolism might be differentially affected by an acute infection that the immune system can successfully clear compared to a chronic persistent infection.

Mitosis is a critical phase of the cell cycle and a vulnerable point where cancer cells can be disrupted, causing cell death and inhibiting tumor growth. Challenges such as drug resistance persist in clinical applications. During mitosis, mRNA translation is generally downregulated, while non-canonical translation of specific transcripts continues. Here, we show that mitotic cancer cells redistribute ribosomes toward the 5' untranslated region (5' UTR) and beginning of the coding sequence (CDS), enhancing translation of thousands of upstream open reading frames (uORFs) and upstream overlapping open reading frames (uoORFs). This mitotic induction of uORF/uoORF enriches human leukocyte antigen (HLA) presentation of non-canonical peptides on the surface of cancer cells after mitotic inhibitor treatment. Functional assays indicate these epitopes provoke cancer-cell killing by T cells. Our findings highlight the therapeutic potential of targeting uORF/uoORF-derived epitopes with mitotic inhibitors to enhance immune recognition and tumor cell elimination.

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.

Small extracellular vesicles (sEVs) released from tumors recruit nociceptor neurons to the tumor bed. Here, we found that ablating these neurons in mouse models of head and neck carcinoma and melanoma reduced the infiltration of myeloid-derived suppressor cells (MDSCs). Moreover, sEV-deficient tumors failed to develop in mice lacking nociceptor neurons. We investigated the interplay between tumor-infiltrating nociceptors and immune cells in head and neck squamous cell carcinoma (HNSCC) and melanoma. Upon exposure to cancer-derived sEVs, mouse dorsal root ganglion (DRG) neurons secreted increased amounts of substance P, IL-6, and injury-associated neuronal markers. Patient-derived sEVs sensitized DRG neurons to capsaicin, implying enhanced nociceptor responsiveness. Furthermore, nociceptors cultured with sEVs induced an immunosuppressed state in CD8+ T cells. Incubation with conditioned medium from cocultures of neurons and cancer cells resulted in increased expression of markers of MDSCs and suppressive function in primary bone marrow cells, and the combination of neuron-conditioned medium and cancer sEVs promoted checkpoint receptor expression on T cells. Together, these findings reveal that nociceptor neurons facilitate CD8+ T cell exhaustion and bolster MDSC infiltration into HNSCC and melanoma. Consequently, targeting nociceptors may provide a strategy to disrupt detrimental neuroimmune cross-talk in cancer and potentiate antitumor immunity.

Th17 cells play a crucial role in autoimmune disease pathogenesis. However, the mechanisms behind the sex differences in immune responses, particularly women's higher susceptibility to autoimmune diseases, remain unclear. This study investigated the role of testosterone in modulating the IL-17 response. IL-17 levels and IL-17-expressing cells were compared between males and females, and testosterone's effect on Th17 differentiation was evaluated. In an imiquimod-induced psoriasis mouse model, testosterone supplementation reduced psoriasis severity in female mice, whereas castration of male mice exacerbated psoriasis. Testosterone inhibited both in vitro Th17 differentiation and in vivo IL-17 expression, correlating with reduced psoriasis severity. Molecular studies indicated that testosterone is an inverse agonist of related orphan receptor gamma (RORγt), a key transcription factor for IL-17 expression. These findings offer mechanistic insights into how testosterone limits tissue inflammation in psoriasis and suggest a basis for developing novel testosterone derivatives to target RORγt and suppress Th17-mediated inflammation.

Interleukin-2 (IL-2) regulates immune homeostasis by fine-tuning the balance between effector and regulatory T (Treg) cells. To identify regulators of IL-2 signaling, we performed genome-wide CRISPR-knockout screening in IL-2-dependent cells derived from a patient with adult T cell leukemia (ATL) and found enrichment of single guide RNAs targeting PRDM1, which encodes B lymphocyte-induced maturation protein 1 (BLIMP1). BLIMP1 inhibits IL-2 production by T cells; however, its role in IL-2 signaling remains unknown. Here, we show that overexpressing Prdm1 down-regulated IL-2 signaling, whereas Prdm1-deficiency enhanced IL-2 signaling in mouse CD4+ T cells and Treg cells with augmented IL-2 signaling in T cells from influenza-infected mice and during adoptive T cell transfer-induced colitis. Deleting PRDM1 in human CD4+ T cells and Treg cells also increased IL-2 signaling. Furthermore, CD4+ T cells from patients with ATL expressed less BLIMP1 and had enhanced IL-2 signaling, whereas overexpressing PRDM1 in ATL cells suppressed IL-2 signaling. Thus, BLIMP1 inhibits IL-2 signaling during normal and pathophysiological responses, suggesting that manipulating BLIMP1 could have therapeutic potential.

Tumor-associated macrophages (TAMs) are among the most prevalent cells within the tumor microenvironment (TME) of cervical cancer (CC). Although TAMs frequently exhibit an immunosuppressive phenotype, their plasticity enables them as an intriguing reprogrammable target for immunotherapy of CC.

Hepatitis B virus (HBV) infection is associated with hepatitis and hepatocellular carcinoma (HCC). Considering that most HBV-infected individuals remain asymptomatic, the mechanism linking HBV to hepatitis and HCC remains uncertain. Herein, we demonstrate that HBV alone does not cause liver inflammation or cancer. Instead, HBV alters the chronic inflammation induced by chemical carcinogens to promote liver carcinogenesis. Long-term HBV genome expression in mouse liver increases liver inflammation and cancer propensity caused by a carcinogen, diethylnitrosamine (DEN). HBV plus DEN-activated interleukin-33 (IL-33)/regulatory T cell axis is required for liver carcinogenesis. Pitavastatin, an IL-33 inhibitor, suppresses HBV plus DEN-induced liver cancer. IL-33 is markedly elevated in HBV+ hepatitis patients, and pitavastatin use significantly correlates with reduced risk of hepatitis and its associated HCC in patients. Collectively, our findings reveal that environmental carcinogens are the link between HBV and HCC risk, creating a window of opportunity for cancer prevention in HBV carriers.

Intermittent fasting (IF), particularly time-restricted feeding (TRF), is increasingly popular has gained popularity for weight loss, yet management, but its effects impact on gut health remain unclear. Remains inadequately understood. This study explores how investigated the effects of TRF effects on intestinal health and explored the underlying mechanisms.

The tumor microenvironment (TME) influences cancer cell metabolism and survival. However, how immune and stromal cells respond to metabolic stress in vivo, and how nutrient limitations affect therapy, remains poorly understood. Here, we introduce Dual Ribosome Profiling (DualRP) to simultaneously monitor translation and ribosome stalling in multiple tumor cell populations. DualRP reveals that cancer-fibroblast interactions trigger an inflammatory program that reduces amino acid shortages during glucose starvation. In immunocompetent mice, we show that serine and glycine are essential for optimal T cell function and that their deficiency impairs T cell fitness. Importantly, immune checkpoint blockade therapy imposes amino acid restrictions specifically in T cells, demonstrating that therapies create distinct metabolic demands across TME cell types. By mapping codon-resolved ribosome stalling in a cell‑type‑specific manner, DualRP uncovers metabolic crosstalk that shapes translational programs. DualRP thus offers a powerful, innovative approach for dissecting tumor cell metabolic interplay and guiding combined metabolic-immunotherapeutic strategies.