InVivoMAb anti-mouse/rat IL-1β

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.

The effectiveness of chemoimmunotherapy for hepatocellular carcinoma (HCC) is hindered by the weak immunogenicity of chemotherapy-induced immunogenic cell death (ICD). This limitation primarily stems from the insufficient activation of the extracellular adenosine triphosphate (eATP)/P2X7 purinergic receptor (P2X7R)/NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome pathway in dendritic cells (DCs). To address this challenge, we designed ivermectin-MnO2 nanocomplexes (IMNs) as P2X7R-targeted nanoimmunoamplifiers to enhance the immunogenicity of chemotherapy-induced ICD. The ivermectin component of IMN enhanced liposomal doxorubicin (LD)-induced ICD and increased P2X7R sensitivity to eATP. Additionally, the MnO2 component of IMN alleviated tumor hypoxia and down-regulated CD39/CD73 expression, thereby preventing eATP degradation. These combined strategies robustly activated the eATP/P2X7R/NLRP3 inflammasome cascade in DCs, eliciting a potent antitumor immune response. In combination with anti-PD-L1 antibody and LD, IMN effectively inhibited tumor growth in orthotopic, subcutaneous, and metastatic HCC mouse models. Our study underscores the crucial role of IMN in amplifying the NLRP3 inflammasome cascade in DCs during ICD, presenting a promising strategy to enhance the efficacy of HCC chemoimmunotherapy.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are severe conditions with high morbidity and mortality with limited effective therapies. Neuroimmune interactions play a critical role in lung homeostasis, but it remains unclear if specific brain regions regulate lung inflammation. Here, we perform anatomical tracing, chemogenetic modulation, and pharmacological interventions in male mice and identify a neural circuit from corticotropin-releasing hormone neurons in the paraventricular nucleus of the hypothalamus (CRHPVN neurons) to the lung. The activation of these neurons protects mice from ALI and promotes survival, reduces neutrophil infiltration and effector functions in the lung, whereas inhibiting CRHPVN neurons worsens ALI. The protective effect is mediated by increased sympathetic nervous activity, with locally released norepinephrine modulating neutrophil functions via β2-AR-β-arrestin2 signaling to inhibit the NF-κB pathway. These findings uncover a brain-lung neural circuit that modulates immune responses during ALI, offering a potential therapeutic target for ALI and ARDS.

High fat diet (HFD)-induced obesity increases the risk and severity of psoriasis. However, the immunoregulatory effects of different HFDs on psoriasis pathogenesis remains poorly understood. Here, mimicking human dietary fat profiles, four HFDs-saturated, monounsaturated, omega-6, and omega-3 fats-were designed and used to induce obesity in mice. Despite comparable obesity levels across groups, only the saturated HFD exacerbated imiquimod (IMQ)-induced psoriasis. This exacerbation correlated with elevated levels of IL-1β-producing macrophages, IL-17A-producing γδ T cells, and neutrophils within psoriatic lesions. Mechanistically, saturated fatty acids (FAs) promoted IL-1β/IL-17A signaling via fatty acid-binding protein 5 (FABP5)-mediated mitochondrial FA oxidation and extracellular ATP release in skin macrophages. Deletion of FABP5, either globally or specifically in macrophages, attenuated IL-1β/IL-17A signaling and alleviated IMQ-induced psoriasis. These findings identify FABP5 as a key mediator of saturated HFD-driven psoriasis via the IL-1β/IL-17 axis, offering insights into the interplay between dietary fats, obesity, and psoriasis.

In metastasis, the dynamics of tumor-immune interactions during micrometastasis remain unclear. Identifying the vulnerabilities of micrometastases before outbreaking into macrometastases can reveal therapeutic opportunities for metastasis. Here, we report a function of T cell immunoglobulin and mucin domain 3 (TIM3) in tumor cells during micrometastasis using breast cancer (BC) metastasis mouse models. TIM3 is highly upregulated in micrometastases, promoting survival, stemness, and immune escape. TIM3+ tumor cells are specifically selected during early seeding of micrometastasis. Mechanistically, TIM3 increases β-catenin/interleukin-1β (IL-1β) signaling, leading to stemness and immune-evasion by inducing immunosuppressive γδ T cells and reducing CD8 T cells during micrometastasis. Clinical data confirm increased TIM3+ tumor cells in BC metastasis and TIM3+ tumor cells as a biomarker of poor outcome in BC patients. (Neo)adjuvant TIM3 blockade reduces the metastatic seeding and incidence in preclinical models. These findings unveil a specific mechanism of micrometastasis immune-evasion and the potential use of TIM3 blockade for subclinical metastasis.

Tumor-induced systemic accumulation and polarization of neutrophils to an immunosuppressive phenotype is a potent driver of metastasis formation. Yet, how mammary tumors reprogram granulopoiesis at the molecular level and when tumor imprinting occurs during neutrophil development remains underexplored. Here, we combined single-cell, chromatin and functional analyses to unravel the tumor-driven reprogramming of granulopoiesis in the bone marrow, along with intervention studies aimed at reversing this process. We observe that mammary tumors accelerate commitment to the neutrophil lineage at the expense of lymphopoiesis and erythropoiesis without stimulating the development of a novel myeloid lineage. Moreover, tumor-directed immunosuppressive imprinting of neutrophils starts early in hematopoiesis. Treatment with anti-IL-1β normalizes tumor-induced granulopoiesis, reducing neutrophil immunosuppressive phenotype and mitigating metastatic spread. Together, these data provide molecular insights into the aberrant, tumor-driven neutrophil differentiation pathway leading to metastasis-promoting chronic inflammation and how it can be reversed to reduce metastatic spread.

Excessive inflammation and cytokine release are hallmarks of severe COVID-19. Certain programmed cell death processes can drive inflammation, however, their role in the pathogenesis of severe COVID-19 is unclear. Pyroptosis is a pro-inflammatory form of regulated cell death initiated by inflammasomes and executed by the pore-forming protein gasdermin D (GSDMD). Using an established mouse adapted SARS-CoV-2 virus and a panel of gene-targeted mice we found that deletion of the inflammasome (NLRP1/3 and the adaptor ASC) and pore forming proteins involved in pyroptosis (GSDMA/C/D/E) only marginally reduced IL-1β levels and did not impact disease outcome or viral loads. Furthermore, we found that SARS-CoV-2 infection did not trigger GSDMD activation in mouse lungs. Finally, we did not observe any difference between WT animals and mice with compound deficiencies in the pro-inflammatory initiator caspases (C1/11/12-/-). This indicates that the classical canonical and non-canonical pro-inflammatory caspases known to process and activate pro-IL-1β, pro-IL-18 and GSDMD do not substantially contribute to SARS-CoV-2 pathogenesis. However, the loss of IL-1β, but not the absence of IL-18, ameliorated disease and enhanced survival in SARS-CoV-2 infected animals compared to wildtype mice. Collectively, these findings demonstrate that IL-1β is an important factor contributing to severe SARS-CoV-2 disease, but its release was largely independent of inflammasome and pyroptotic pathways.

Oral squamous cell carcinoma (OSCC), one of the most prevalent and aggressive forms of head and neck squamous cell carcinoma, has a five-year survival rate of about 50% ~ 60%, emphasizing the urgent need for more effective therapeutic strategies. Solute carrier family 7 member 11 (SLC7A11) is overexpressed in various cancers and represents a potential therapeutic target. Sulfasalazine (SAS), a Food and Drug Administration-approved drug, is a potent inhibiter of SLC7A11. However, SAS can also increase the levels of pro-inflammatory cytokines such as IL-1β, which may suppress the immune response. Here, we investigate the effect of SAS combined with anti-IL-1β monoclonal antibody (anti-IL-1β mAb) as a novel treatment strategy for OSCC. In this study, SLC7A11 was markedly increased in OSCC tissues, and high SLC7A11 expression predicted poor prognosis. SAS treatment was shown to suppress OSCC cell proliferation and trigger ferroptosis, as evidenced by elevated reactive oxygen species, reduced glutathione and enhanced lipid peroxidation. SAS also elevated IL-1β levels, leading to T cell exhaustion. Combining SAS with anti-IL-1β mAb reversed T cell exhaustion and amplified the anti-tumor effects in vitro. In the 4-nitroquinoline-1-oxide-induced oral cancergenisis model, the combination treatment significantly inhibited oral carcinogenesis compared to monotherapy. Our results suggest that combining SAS with anti-IL-1β mAb enhances the anti-tumor efficacy against OSCC through tumor growth inhibition and immune modulation, offering a promising therapeutic strategy.

The regeneration of the enthesis remains a formidable challenge in regenerative medicine. However, key regulators underlying unsatisfactory regeneration remain poorly understood. This study reveals that the purinergic receptor P2X7 (P2X7R)/Nod-like receptor family protein 3 (NLRP3) inflammasome axis suppresses enthesis regeneration by amplifying IL-1β-mediated inflammatory cross-talk and suppressing docosatrienoic acid (DTA) metabolic cross-talk. NLRP3 inflammasomes were activated in macrophages following enthesis injury, thereby impairing the histological and functional recovery of the injured enthesis. Single-cell RNA sequencing (scRNA-seq) indicated that Nlrp3 knockout attenuated pathological inflammation and ameliorated the detrimental effects of IL-1β signaling cross-talk. Furthermore, NLRP3 inflammasomes suppressed the secretion of anti-inflammatory cytokines (IL-10 and IL-13) and DTA. The NLRP3 inflammasome-mediated secretome reduced differentiation and migration of stem cells. Neutralizing IL-1β or replenishing docosatrienoic acid accelerated enthesis regeneration. Moreover, conditional knockout of P2rx7 in myeloid cells attenuated NLRP3 inflammasome activation and facilitated enthesis regeneration. This study demonstrates that the P2X7R/NLRP3 inflammasome axis represents a promising therapeutic target for enthesis repair.

Inducing ferroptosis in tumor cells is emerging as a strategy for treating malignancies that are refractory to traditional treatment modalities. However, the consequences of ferroptosis of immune cells in the tumor microenvironment need to be better understood in order to realize the potential of this approach. In this study, we discovered that neutrophils in chemoresistant breast cancer are highly sensitive to ferroptosis. Reduction of the acyltransferase MOAT1 in chemoresistance-associated neutrophils induced phospholipid reprogramming, switching the preference from monounsaturated fatty acids to polyunsaturated fatty acids, which increased their susceptibility to ferroptosis. Ferroptotic neutrophils secreted PGE2, IDO, and oxidized lipids that suppressed the proliferation and cytotoxicity of antitumor CD8+ T cells. Furthermore, neutrophil ferroptosis was closely related to a distinct subset of IL1β+CXCL3+CD4+ (Fer-CD4) T lymphocytes, which were enriched in chemoresistant tumors. Fer-CD4 T cells orchestrated neutrophil ferroptosis by modulating MOAT1 expression via IL1β/IL1R1/NF-κB signaling. Moreover, Fer-CD4 T cells secreted CXCL3, IL8, and S100A9 to replenish the neutrophil pool in the tumor microenvironment. Ferroptotic neutrophils in turn fostered Fer-CD4 T-cell differentiation. In spontaneous tumorigenesis mouse models, targeting IL1β+ CD4+ T cells or IL1R1+ neutrophils broke the cross-talk, restraining neutrophil ferroptosis, enhancing antitumor immunity, and overcoming chemoresistance. Overall, these findings uncover the role of neutrophil ferroptosis in shaping the immune landscape and propose appealing targets for restoring immunosurveillance and chemosensitivity in breast cancer. Significance: In chemoresistant breast cancer, IL1β+CXCL3+CD4+ T cells mediate neutrophil ferroptosis that suppresses antitumor immunity, indicating that interfering with this intercellular cross-talk could be an attractive strategy to reverse chemoresistance.

Oral squamous cell carcinoma (OSCC) remains a major death cause in head and neck cancers, but the exact pathogenesis mechanisms of OSCC are largely unclear.

Aging progresses through the interaction of metabolic processes, including changes in the immune and endocrine systems. Glucocorticoids (GCs), which are regulated by the hypothalamic-pituitary-adrenal (HPA) axis, play an important role in regulating metabolism and immune responses. However, the age-related changes in the secretion mechanisms of GCs remain elusive. Here, we found that corticosterone (CORT) secretion follows a circadian rhythm in young mice, whereas it oversecreted throughout the day in aged mice >18 months old, resulting in the disappearance of diurnal variation. Furthermore, senescent cells progressively accumulated in the zF of the adrenal gland as mice aged beyond 18 months. This accumulation was accompanied by an increase in the number of Ad4BP/SF1 (SF1), a key transcription factor, strongly expressing cells (SF1-high positive: HP). Removal of senescent cells with senolytics, dasatinib, and quercetin resulted in the reduction of the number of SF1-HP cells and recovery of CORT diurnal oscillation in 24-month-old mice. Similarly, administration of a neutralizing antibody against IL1β, which was found to be strongly expressed in the adrenocortical cells of the zF, resulted in a marked decrease in SF1-HP cells and restoration of the CORT circadian rhythm. Our findings suggest that the disappearance of CORT diurnal oscillation is a characteristic of aging individuals and is caused by the secretion of IL1β, one of the SASPs, from senescent cells that accumulate in the zF of the adrenal cortex. These findings provide a novel insight into aging. Age-related hypersecretory GCs could be a potential therapeutic target for aging-related diseases.

Although survival from breast cancer has dramatically increased, many will develop recurrent, metastatic disease. Unfortunately, survival for this stage of disease remains very low. Activating the immune system has incredible promise since it has the potential to be curative. However, immune checkpoint blockade (ICB) which works through T cells has been largely disappointing for metastatic breast cancer. One reason for this is a suppressive myeloid immune compartment that is unaffected by ICB. Cholesterol metabolism and proteins involved in cholesterol homeostasis play important regulatory roles in myeloid cells. Here, we demonstrate that NR0B2, a nuclear receptor involved in negative feedback of cholesterol metabolism, works in several myeloid cell types to impair subsequent expansion of regulatory T cells (Tregs); Tregs being a subset known to be highly immune suppressive and associated with poor therapeutic response. Within myeloid cells, NR0B2 serves to decrease many aspects of the inflammasome, ultimately resulting in decreased IL1β; IL1β driving Treg expansion. Importantly, mice lacking NR0B2 exhibit accelerated tumor growth. Thus, NR0B2 represents an important node in myeloid cells dictating ensuing Treg expansion and tumor growth, thereby representing a novel therapeutic target to re-educate these cells, having impact across different solid tumor types. Indeed, a paper co-published in this issue demonstrates the therapeutic utility of targeting NR0B2.

Immune checkpoint blockade (ICB) has had limited utility in several solid tumors such as breast cancer, a major cause of cancer-related mortality in women. Therefore, there is considerable interest in alternate strategies to promote an anti-cancer immune response. A paper co-published in this issue describes how NR0B2, a protein involved in cholesterol homeostasis, functions within myeloid immune cells to modulate the inflammasome and reduce the expansion of immune-suppressive regulatory T cells (Treg). Here, we develop NR0B2 as a potential therapeutic target. NR0B2 in tumors is associated with improved survival for several cancer types including breast. Importantly, NR0B2 expression is also prognostic of ICB success. Within breast tumors, NR0B2 expression is inversely associated with FOXP3, a marker of Tregs. While a described agonist (DSHN) had some efficacy, it required high doses and long treatment times. Therefore, we designed and screened several derivatives. A methyl ester derivative (DSHN-OMe) emerged as superior in terms of (1) cellular uptake, (2) ability to regulate expected expression of genes, (3) suppression of Treg expansion using in vitro co-culture systems, and (4) efficacy against the growth of primary and metastatic tumors. This work identifies NR0B2 as a target to re-educate myeloid immune cells and a novel ligand with significant anti-tumor efficacy in preclinical models.

Pyroptosis is a lytic cell death mode that helps limit the spread of infections and is also linked to pathology in sterile inflammatory diseases and autoimmune diseases1-4. During pyroptosis, inflammasome activation and the engagement of caspase-1 lead to cell death, along with the maturation and secretion of the inflammatory cytokine interleukin-1β (IL-1β). The dominant effect of IL-1β in promoting tissue inflammation has clouded the potential influence of other factors released from pyroptotic cells. Here, using a system in which macrophages are induced to undergo pyroptosis without IL-1β or IL-1α release (denoted Pyro-1), we identify unexpected beneficial effects of the Pyro-1 secretome. First, we noted that the Pyro-1 supernatants upregulated gene signatures linked to migration, cellular proliferation and wound healing. Consistent with this gene signature, Pyro-1 supernatants boosted migration of primary fibroblasts and macrophages, and promoted faster wound closure in vitro and improved tissue repair in vivo. In mechanistic studies, lipidomics and metabolomics of the Pyro-1 supernatants identified the presence of both oxylipins and metabolites, linking them to pro-wound-healing effects. Focusing specifically on the oxylipin prostaglandin E2 (PGE2), we find that its synthesis is induced de novo during pyroptosis, downstream of caspase-1 activation and cyclooxygenase-2 activity; further, PGE2 synthesis occurs late in pyroptosis, with its release dependent on gasdermin D pores opened during pyroptosis. As for the pyroptotic metabolites, they link to immune cell infiltration into the wounds, and polarization to CD301+ macrophages. Collectively, these data advance the concept that the pyroptotic secretome possesses oxylipins and metabolites with tissue repair properties that may be harnessed therapeutically.

There is no treatment for acute aortic dissection (AAD) targeting inflammatory cells. We aimed to identify the new therapeutic targets associated with inflammatory cells. We characterized the specific distribution of myeloid cells of both human type A AAD samples and a murine AAD model generated using angiotensin II (ANGII) and β-aminopropionitrile (BAPN) by single-cell RNA sequencing (scRNA-seq). We also examined the effect of an anti-interleukin-1β (IL-1β) antibody in the murine AAD model. IL1B+ inflammatory macrophages and classical monocytes were increased in human AAD samples. Trajectory analysis demonstrated that IL1B+ inflammatory macrophages differentiated from S100A8/9/12+ classical monocytes uniquely observed in the aorta of AAD. We found increased infiltration of neutrophils and monocytes with the expression of inflammatory cytokines in the aorta and accumulation of inflammatory macrophages before the onset of macroscopic AAD in the murine AAD model. In blocking experiments using an anti-IL-1β antibody, it improved survival of murine AAD model by preventing elastin degradation. We observed the accumulation of inflammatory macrophages expressing IL-1β in both human AAD samples and in a murine AAD model. Anti-IL-1β antibody could improve the mortality rate in mice, suggesting that it may be a treatment option for AAD.

Aging is intricately linked to immune system dysfunction. Recent studies have highlighted the biological function of microRNA-7 (miR-7) as a novel regulator of immune cell function and related diseases. However, the potential role of miR-7 in aging remains unexplored. Here, we investigated the contribution of miR-7 to d-gal-induced aging in mice, focusing on its regulation of senescent Kupffer cells. Our findings revealed that miR-7 deficiency significantly ameliorated the aging process, characterized by enhanced CD4+ T-cell activation. However, the adoptive transfer of miR-7-deficient CD4+T cells failed to improve the age-related phenotype. Further analysis showed that miR-7 deficiency significantly reduced IL-1β production in liver tissue, and inhibiting IL-1β in vivo slowed down the aging process in mice. Notably, IL-1β is mainly produced by senescent Kupffer cells in the liver tissue of aging mice, and miR-7 expression was significantly up-regulated in these cells. Mechanistically, KLF4, a target of miR-7, was down-regulated in senescent Kupffer cells in aging mouse model. Furthermore, miR-7 deficiency also modulated the NF-κB activation and IL-1β production in senescent Kupffer cells through KLF4. In conclusion, our findings unveil the role of miR-7 in d-gal-induced aging in mice, highlighting its regulation of KLF4/NF-κB/IL-1β pathways in senescent Kupffer cells. This research may enhance our understanding of miRNA-based aging immune cells and offer new avenues for new intervention strategies in aging process.

Lung tissue resident memory (TRM) cells are thought to play crucial roles in lung host defense. We have recently shown that immunization with the adjuvant LTA1 (derived from the A1 domain of E. coli heat labile toxin) admixed with OmpX from K. pneumoniae can elicit antigen specific lung Th17 TRM cells that provide serotype independent immunity to members of the Enterobacteriaceae family. However, the upstream requirements to generate these cells are unclear. Single-cell RNA-seq showed that vaccine-elicited Th17 TRM cells expressed high levels of IL-1R1, suggesting that IL-1 family members may be critical to generate these cells. Using a combination of genetic and antibody neutralization approaches, we show that Th17 TRM cells can be generated independent of caspase-1 but are compromised when IL-1α is neutralized. Moreover IL-1α could serve as a molecular adjuvant to generate lung Th17 TRM cells independent of LTA1. Taken together, these data suggest that IL-1α plays a major role in vaccine-mediated lung Th17 TRM generation.

Acute myeloid leukemia (AML) progression is influenced by immune suppression induced by leukemia cells. ZEB1, a critical transcription factor in epithelial-to-mesenchymal transition, demonstrates immune regulatory functions in AML. Silencing ZEB1 in leukemic cells reduces engraftment and extramedullary disease in immune-competent mice, activating CD8 T lymphocytes and limiting Th17 cell expansion. ZEB1 in AML cells directly promotes Th17 cell development that, in turn, creates a self-sustaining loop and a pro-invasive phenotype, favoring transforming growth factor β (TGF-β), interleukin-23 (IL-23), and SOCS2 gene transcription. In bone marrow biopsies from AML patients, immunohistochemistry shows a direct correlation between ZEB1 and Th17. Also, the analysis of ZEB1 expression in larger datasets identifies two distinct AML groups, ZEB1high and ZEB1low, each with specific immunological and molecular traits. ZEB1high patients exhibit increased IL-17, SOCS2, and TGF-β pathways and a negative association with overall survival. This unveils ZEB1's dual role in AML, entwining pro-tumoral and immune regulatory capacities in AML blasts.