InVivoMAb anti-mouse Ly6G
Product Details
The 1A8 monoclonal antibody reacts with mouse Ly6G. Ly6G is a 21-25 kDa member of the Ly-6 superfamily of GPI-anchored cell surface proteins with roles in cell signaling and cell adhesion. Ly6G is expressed differentially during development by cells in the myeloid lineage including monocytes, macrophages, granulocytes, and neutrophils. Monocytes typically express Ly6G transiently during development while mature granulocytes and peripheral neutrophils retain expression making Ly6G a good cell surface marker for these populations. Unlike the RB6-8C5 antibody, the 1A8 antibody reacts specifically with mouse Ly6G with no reported cross reactivity with Ly6C.Specifications
| Isotype | Rat IgG2a,Ā Īŗ |
|---|---|
| Recommended Isotype Control(s) | InVivoMAb rat IgG2a isotype control, anti-trinitrophenol |
| Recommended Dilution Buffer | InVivoPure pH 7.0 Dilution Buffer |
| Conjugation | This product is unconjugated. Conjugation is available via our Antibody Conjugation Services. |
| Immunogen | EL4J cells transfected with Ly6G |
| Reported Applications |
in vivo neutrophil depletion in vivo MDSC depletion Immunofluorescence Immunohistochemistry (paraffin) Immunohistochemistry (frozen) Flow cytometry |
| Formulation |
PBS, pH 7.0 Contains no stabilizers or preservatives |
| Endotoxin |
<2EU/mg (<0.002EU/Ī¼g) Determined by LAL gel clotting assay |
| Purity |
>95% Determined by SDS-PAGE |
| Sterility | 0.2 Āµm filtration |
| Purification | Protein G |
| RRID | AB_1107721 |
| Molecular Weight | 150 kDa |
| Storage | The antibody solution should be stored at the stock concentration at 4Ā°C. Do not freeze. |
Additional Formats
Recommended Products
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Recommended Isotype Control(s)
InVivoMAb rat IgG2a isotype control, anti-trinitrophenol
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Recommended Dilution Buffer
InVivoPure pH 7.0 Dilution Buffer
in vivo neutrophil depletion
Davis, R. W. t., et al. (2018). "Luminol Chemiluminescence Reports Photodynamic Therapy-Generated Neutrophil Activity In Vivo and Serves as a Biomarker of Therapeutic Efficacy" Photochem Photobiol . PubMed
Inflammatory cells, most especially neutrophils, can be a necessary component of the antitumor activity occurring after administration of photodynamic therapy. Generation of neutrophil responses has been suggested to be particularly important in instances when the delivered photodynamic therapy (PDT) dose is insufficient. In these cases, the release of neutrophil granules and engagement of antitumor immunity may play an important role in eliminating residual disease. Herein, we utilize in vivo imaging of luminol chemiluminescence to noninvasively monitor neutrophil activation after PDT administration. Studies were performed in the AB12 murine model of mesothelioma, treated with Photofrin-PDT. Luminol-generated chemiluminescence increased transiently 1 h after PDT, followed by a subsequent decrease at 4 h after PDT. The production of luminol signal was not associated with the influx of Ly6G(+) cells, but was related to oxidative burst, as an indicator of neutrophil function. Most importantly, greater levels of luminol chemiluminescence 1 h after PDT were prognostic of a complete response at 90 days after PDT. Taken together, this research supports an important role for early activity by Ly6G(+) cells in the generation of long-term PDT responses in mesothelioma, and it points to luminol chemiluminescence as a potentially useful approach for preclinical monitoring of neutrophil activation by PDT.
in vivo neutrophil depletion
Moynihan, K. D., et al. (2016). "Eradication of large established tumors in mice by combination immunotherapy that engages innate and adaptive immune responses" Nat Med. doi : 10.1038/nm.4200. PubMed
Checkpoint blockade with antibodies specific for cytotoxic T lymphocyte-associated protein (CTLA)-4 or programmed cell death 1 (PDCD1; also known as PD-1) elicits durable tumor regression in metastatic cancer, but these dramatic responses are confined to a minority of patients. This suboptimal outcome is probably due in part to the complex network of immunosuppressive pathways present in advanced tumors, which are unlikely to be overcome by intervention at a single signaling checkpoint. Here we describe a combination immunotherapy that recruits a variety of innate and adaptive immune cells to eliminate large tumor burdens in syngeneic tumor models and a genetically engineered mouse model of melanoma; to our knowledge tumors of this size have not previously been curable by treatments relying on endogenous immunity. Maximal antitumor efficacy required four components: a tumor-antigen-targeting antibody, a recombinant interleukin-2 with an extended half-life, anti-PD-1 and a powerful T cell vaccine. Depletion experiments revealed that CD8+ T cells, cross-presenting dendritic cells and several other innate immune cell subsets were required for tumor regression. Effective treatment induced infiltration of immune cells and production of inflammatory cytokines in the tumor, enhanced antibody-mediated tumor antigen uptake and promoted antigen spreading. These results demonstrate the capacity of an elicited endogenous immune response to destroy large, established tumors and elucidate essential characteristics of combination immunotherapies that are capable of curing a majority of tumors in experimental settings typically viewed as intractable.
in vivo neutrophil depletion
Conde, P., et al. (2015). "DC-SIGN(+) Macrophages Control the Induction of Transplantation Tolerance" Immunity 42(6): 1143-1158. PubMed
Tissue effector cells of the monocyte lineage can differentiate into different cell types with specific cell function depending on their environment. The phenotype, developmental requirements, and functional mechanisms of immune protective macrophages that mediate the induction of transplantation tolerance remain elusive. Here, we demonstrate that costimulatory blockade favored accumulation of DC-SIGN-expressing macrophages that inhibited CD8(+) T cell immunity and promoted CD4(+)Foxp3(+) Treg cell expansion in numbers. Mechanistically, that simultaneous DC-SIGN engagement by fucosylated ligands and TLR4 signaling was required for production of immunoregulatory IL-10 associated with prolonged allograft survival. Deletion of DC-SIGN-expressing macrophages in vivo, interfering with their CSF1-dependent development, or preventing the DC-SIGN signaling pathway abrogated tolerance. Together, the results provide new insights into the tolerogenic effects of costimulatory blockade and identify DC-SIGN(+) suppressive macrophages as crucial mediators of immunological tolerance with the concomitant therapeutic implications in the clinic.
in vivo neutrophil depletion
Griseri, T., et al. (2015). "Granulocyte Macrophage Colony-Stimulating Factor-Activated Eosinophils Promote Interleukin-23 Driven Chronic Colitis" Immunity 43(1): 187-199. PubMed
The role of intestinal eosinophils in immune homeostasis is enigmatic and the molecular signals that drive them from protective to tissue damaging are unknown. Most commonly associated with Th2 cell-mediated diseases, we describe a role for eosinophils as crucial effectors of the interleukin-23 (IL-23)-granulocyte macrophage colony-stimulating factor (GM-CSF) axis in colitis. Chronic intestinal inflammation was characterized by increased bone marrow eosinopoiesis and accumulation of activated intestinal eosinophils. IL-5 blockade or eosinophil depletion ameliorated colitis, implicating eosinophils in disease pathogenesis. GM-CSF was a potent activator of eosinophil effector functions and intestinal accumulation, and GM-CSF blockade inhibited chronic colitis. By contrast neutrophil accumulation was GM-CSF independent and dispensable for colitis. In addition to TNF secretion, release of eosinophil peroxidase promoted colitis identifying direct tissue-toxic mechanisms. Thus, eosinophils are key perpetrators of chronic inflammation and tissue damage in IL-23-mediated immune diseases and it suggests the GM-CSF-eosinophil axis as an attractive therapeutic target.
in vivo neutrophil depletion, Flow Cytometry, Immunohistochemistry (paraffin)
Coffelt, S. B., et al. (2015). "IL-17-producing gammadelta T cells and neutrophils conspire to promote breast cancer metastasis" Nature 522(7556): 345-348. PubMed
Metastatic disease remains the primary cause of death for patients with breast cancer. The different steps of the metastatic cascade rely on reciprocal interactions between cancer cells and their microenvironment. Within this local microenvironment and in distant organs, immune cells and their mediators are known to facilitate metastasis formation. However, the precise contribution of tumour-induced systemic inflammation to metastasis and the mechanisms regulating systemic inflammation are poorly understood. Here we show that tumours maximize their chance of metastasizing by evoking a systemic inflammatory cascade in mouse models of spontaneous breast cancer metastasis. We mechanistically demonstrate that interleukin (IL)-1beta elicits IL-17 expression from gamma delta (gammadelta) T cells, resulting in systemic, granulocyte colony-stimulating factor (G-CSF)-dependent expansion and polarization of neutrophils in mice bearing mammary tumours. Tumour-induced neutrophils acquire the ability to suppress cytotoxic T lymphocytes carrying the CD8 antigen, which limit the establishment of metastases. Neutralization of IL-17 or G-CSF and absence of gammadelta T cells prevents neutrophil accumulation and downregulates the T-cell-suppressive phenotype of neutrophils. Moreover, the absence of gammadelta T cells or neutrophils profoundly reduces pulmonary and lymph node metastases without influencing primary tumour progression. Our data indicate that targeting this novel cancer-cell-initiated domino effect within the immune systemāthe gammadelta T cell/IL-17/neutrophil axisārepresents a new strategy to inhibit metastatic disease.
in vivo neutrophil depletion, Flow Cytometry, Immunohistochemistry (paraffin), Immunohistochemistry (frozen)
Finisguerra, V., et al. (2015). "MET is required for the recruitment of anti-tumoural neutrophils" Nature 522(7556): 349-353. PubMed
Mutations or amplification of the MET proto-oncogene are involved in the pathogenesis of several tumours, which rely on the constitutive engagement of this pathway for their growth and survival. However, MET is expressed not only by cancer cells but also by tumour-associated stromal cells, although its precise role in this compartment is not well characterized. Here we show that MET is required for neutrophil chemoattraction and cytotoxicity in response to its ligand hepatocyte growth factor (HGF). Met deletion in mouse neutrophils enhances tumour growth and metastasis. This phenotype correlates with reduced neutrophil infiltration to both the primary tumour and metastatic sites. Similarly, Met is necessary for neutrophil transudation during colitis, skin rash or peritonitis. Mechanistically, Met is induced by tumour-derived tumour necrosis factor (TNF)-alpha or other inflammatory stimuli in both mouse and human neutrophils. This induction is instrumental for neutrophil transmigration across an activated endothelium and for inducible nitric oxide synthase production upon HGF stimulation. Consequently, HGF/MET-dependent nitric oxide release by neutrophils promotes cancer cell killing, which abates tumour growth and metastasis. After systemic administration of a MET kinase inhibitor, we prove that the therapeutic benefit of MET targeting in cancer cells is partly countered by the pro-tumoural effect arising from MET blockade in neutrophils. Our work identifies an unprecedented role of MET in neutrophils, suggests a potential āAchillesā heelā of MET-targeted therapies in cancer, and supports the rationale for evaluating anti-MET drugs in certain inflammatory diseases.
in vivo neutrophil depletion
Yamada, D. H., et al. (2015). "Suppression of Fcgamma-receptor-mediated antibody effector function during persistent viral infection" Immunity 42(2): 379-390. PubMed
Understanding how viruses subvert host immunity and persist is essential for developing strategies to eliminate infection. T cell exhaustion during chronic viral infection is well described, but effects on antibody-mediated effector activity are unclear. Herein, we show that increased amounts of immune complexes generated in mice persistently infected with lymphocytic choriomeningitis virus (LCMV) suppressed multiple Fcgamma-receptor (FcgammaR) functions. The high amounts of immune complexes suppressed antibody-mediated cell depletion, therapeutic antibody-killing of LCMV infected cells and human CD20-expressing tumors, as well as reduced immune complex-mediated cross-presentation to T cells. Suppression of FcgammaR activity was not due to inhibitory FcgammaRs or high concentrations of free antibody, and proper FcgammaR functions were restored when persistently infected mice specifically lacked immune complexes. Thus, we identify a mechanism of immunosuppression during viral persistence with implications for understanding effective antibody activity aimed at pathogen control.
in vivo neutrophil depletion
Ellis, G. T., et al. (2015). "TRAIL+ monocytes and monocyte-related cells cause lung damage and thereby increase susceptibility to influenza-Streptococcus pneumoniae coinfection" EMBO Rep 16(9): 1203-1218. PubMed
Streptococcus pneumoniae coinfection is a major cause of influenza-associated mortality; however, the mechanisms underlying pathogenesis or protection remain unclear. Using a clinically relevant mouse model, we identify immune-mediated damage early during coinfection as a new mechanism causing susceptibility. Coinfected CCR2(-/-) mice lacking monocytes and monocyte-derived cells control bacterial invasion better, show reduced epithelial damage and are overall more resistant than wild-type controls. In influenza-infected wild-type lungs, monocytes and monocyte-derived cells are the major cell populations expressing the apoptosis-inducing ligand TRAIL. Accordingly, anti-TRAIL treatment reduces bacterial load and protects against coinfection if administered during viral infection, but not following bacterial exposure. Post-influenza bacterial outgrowth induces a strong proinflammatory cytokine response and massive inflammatory cell infiltrate. Depletion of neutrophils or blockade of TNF-alpha facilitate bacterial outgrowth, leading to increased mortality, demonstrating that these factors aid bacterial control. We conclude that inflammatory monocytes recruited early, during the viral phase of coinfection, induce TRAIL-mediated lung damage, which facilitates bacterial invasion, while TNF-alpha and neutrophil responses help control subsequent bacterial outgrowth. We thus identify novel determinants of protection versus pathology in influenza-Streptococcus pneumoniae coinfection.
in vivo neutrophil depletion, Flow Cytometry
Moser, E. K., et al. (2014). "Late engagement of CD86 after influenza virus clearance promotes recovery in a FoxP3+ regulatory T cell dependent manner" PLoS Pathog 10(8): e1004315. PubMed
Influenza A virus (IAV) infection in the respiratory tract triggers robust innate and adaptive immune responses, resulting in both virus clearance and lung inflammation and injury. After virus clearance, resolution of ongoing inflammation and tissue repair occur during a distinct recovery period. B7 family co-stimulatory molecules such as CD80 and CD86 have important roles in modulating T cell activity during the initiation and effector stages of the host response to IAV infection, but their potential role during recovery and resolution of inflammation is unknown. We found that antibody-mediated CD86 blockade in vivo after virus clearance led to a delay in recovery, characterized by increased numbers of lung neutrophils and inflammatory cytokines in airways and lung interstitium, but no change in conventional IAV-specific T cell responses. However, CD86 blockade led to decreased numbers of FoxP3+ regulatory T cells (Tregs), and adoptive transfer of Tregs into alphaCD86 treated mice rescued the effect of the blockade, supporting a role for Tregs in promoting recovery after virus clearance. Specific depletion of Tregs late after infection mimicked the CD86 blockade phenotype, confirming a role for Tregs during recovery after virus clearance. Furthermore, we identified neutrophils as a target of Treg suppression since neutrophil depletion in Treg-depleted mice reduced excess inflammatory cytokines in the airways. These results demonstrate that Tregs, in a CD86 dependent mechanism, contribute to the resolution of disease after IAV infection, in part by suppressing neutrophil-driven cytokine release into the airways.
in vivo neutrophil depletion, Flow Cytometry
Chen, K. W., et al. (2014). "The neutrophil NLRC4 inflammasome selectively promotes IL-1beta maturation without pyroptosis during acute Salmonella challenge" Cell Rep 8(2): 570-582. PubMed
The macrophage NLRC4 inflammasome drives potent innate immune responses against Salmonella by eliciting caspase-1-dependent proinflammatory cytokine production (e.g., interleukin-1beta [IL-1beta]) and pyroptotic cell death. However, the potential contribution of other cell types to inflammasome-mediated host defense against Salmonella was unclear. Here, we demonstrate that neutrophils, typically viewed as cellular targets of IL-1beta, themselves activate the NLRC4 inflammasome during acute Salmonella infection and are a major cell compartment for IL-1beta production during acute peritoneal challenge in vivo. Importantly, unlike macrophages, neutrophils do not undergo pyroptosis upon NLRC4 inflammasome activation. The resistance of neutrophils to pyroptotic death is unique among inflammasome-signaling cells so far described and allows neutrophils to sustain IL-1beta production at a site of infection without compromising the crucial inflammasome-independent antimicrobial effector functions that would be lost if neutrophils rapidly lysed upon caspase-1 activation. Inflammasome pathway modification in neutrophils thus maximizes host proinflammatory and antimicrobial responses during pathogen challenge.
in vivo neutrophil depletion
Deshmukh, H. S., et al. (2014). "The microbiota regulates neutrophil homeostasis and host resistance to Escherichia coli K1 sepsis in neonatal mice" Nat Med 20(5): 524-530. PubMed
Neonatal colonization by microbes, which begins immediately after birth, is influenced by gestational age and the motherās microbiota and is modified by exposure to antibiotics. In neonates, prolonged duration of antibiotic therapy is associated with increased risk of late-onset sepsis (LOS), a disorder controlled by neutrophils. A role for the microbiota in regulating neutrophil development and susceptibility to sepsis in the neonate remains unclear. We exposed pregnant mouse dams to antibiotics in drinking water to limit transfer of maternal microbes to the neonates. Antibiotic exposure of dams decreased the total number and composition of microbes in the intestine of the neonates. This was associated with decreased numbers of circulating and bone marrow neutrophils and granulocyte/macrophage-restricted progenitor cells in the bone marrow of antibiotic-treated and germ-free neonates. Antibiotic exposure of dams reduced the number of interleukin-17 (IL-17)-producing cells in the intestine and production of granulocyte colony-stimulating factor (G-CSF). Granulocytopenia was associated with impaired host defense and increased susceptibility to Escherichia coli K1 and Klebsiella pneumoniae sepsis in antibiotic-treated neonates, which could be partially reversed by administration of G-CSF. Transfer of a normal microbiota into antibiotic-treated neonates induced IL-17 production by group 3 innate lymphoid cells (ILCs) in the intestine, increasing plasma G-CSF levels and neutrophil numbers in a Toll-like receptor 4 (TLR4)- and myeloid differentiation factor 88 (MyD88)-dependent manner and restored IL-17-dependent resistance to sepsis. Specific depletion of ILCs prevented IL-17- and G-CSF-dependent granulocytosis and resistance to sepsis. These data support a role for the intestinal microbiota in regulation of granulocytosis, neutrophil homeostasis and host resistance to sepsis in neonates.
in vivo MDSC depletion
Deng, L., et al. (2014). "Irradiation and anti-PD-L1 treatment synergistically promote antitumor immunity in mice" J Clin Invest 124(2): 687-695. PubMed
High-dose ionizing irradiation (IR) results in direct tumor cell death and augments tumor-specific immunity, which enhances tumor control both locally and distantly. Unfortunately, local relapses often occur following IR treatment, indicating that IR-induced responses are inadequate to maintain antitumor immunity. Therapeutic blockade of the T cell negative regulator programmed death-ligand 1 (PD-L1, also called B7-H1) can enhance T cell effector function when PD-L1 is expressed in chronically inflamed tissues and tumors. Here, we demonstrate that PD-L1 was upregulated in the tumor microenvironment after IR. Administration of anti-PD-L1 enhanced the efficacy of IR through a cytotoxic T cell-dependent mechanism. Concomitant with IR-mediated tumor regression, we observed that IR and anti-PD-L1 synergistically reduced the local accumulation of tumor-infiltrating myeloid-derived suppressor cells (MDSCs), which suppress T cells and alter the tumor immune microenvironment. Furthermore, activation of cytotoxic T cells with combination therapy mediated the reduction of MDSCs in tumors through the cytotoxic actions of TNF. Our data provide evidence for a close interaction between IR, T cells, and the PD-L1/PD-1 axis and establish a basis for the rational design of combination therapy with immune modulators and radiotherapy.
in vivo neutrophil depletion, Flow Cytometry, Immunohistochemistry (frozen)
Huang, L. R., et al. (2013). "Intrahepatic myeloid-cell aggregates enable local proliferation of CD8(+) T cells and successful immunotherapy against chronic viral liver infection" Nat Immunol 14(6): 574-583. PubMed
Chronic infection is difficult to overcome because of exhaustion or depletion of cytotoxic effector CD8(+) T cells (cytotoxic T lymphoytes (CTLs)). Here we report that signaling via Toll-like receptors (TLRs) induced intrahepatic aggregates of myeloid cells that enabled the population expansion of CTLs (iMATEs: āintrahepatic myeloid-cell aggregates for T cell population expansionā) without causing immunopathology. In the liver, CTL proliferation was restricted to iMATEs that were composed of inflammatory monocyte-derived CD11b(+) cells. Signaling via tumor-necrosis factor (TNF) caused iMATE formation that facilitated costimulation dependent on the receptor OX40 for expansion of the CTL population. The iMATEs arose during acute viral infection but were absent during chronic viral infection, yet they were still induced by TLR signaling. Such hepatic expansion of the CTL population controlled chronic viral infection of the liver after vaccination with DNA. Thus, iMATEs are dynamic structures that overcome regulatory cues that limit the population expansion of CTLs during chronic infection and can be used in new therapeutic vaccination strategies.
in vivo neutrophil depletion
Richter, K., et al. (2013). "Macrophage and T cell produced IL-10 promotes viral chronicity" PLoS Pathog 9(11): e1003735. PubMed
Chronic viral infections lead to CD8(+) T cell exhaustion, characterized by impaired cytokine secretion. Presence of the immune-regulatory cytokine IL-10 promotes chronicity of Lymphocytic Choriomeningitis Virus (LCMV) Clone 13 infection, while absence of IL-10/IL-10R signaling early during infection results in viral clearance and higher percentages and numbers of antiviral, cytokine producing T cells. IL-10 is produced by several cell types during LCMV infection but it is currently unclear which cellular sources are responsible for induction of viral chronicity. Here, we demonstrate that although dendritic cells produce IL-10 and overall IL-10 mRNA levels decrease significantly in absence of CD11c(+) cells, absence of IL-10 produced by CD11c(+) cells failed to improve the LCMV-specific T cell response and control of LCMV infection. Similarly, NK cell specific IL-10 deficiency had no positive impact on the LCMV-specific T cell response or viral control, even though high percentages of NK cells produced IL-10 at early time points after infection. Interestingly, we found markedly improved T cell responses and clearance of normally chronic LCMV Clone 13 infection when either myeloid cells or T cells lacked IL-10 production and mice depleted of monocytes/macrophages or CD4(+) T cells exhibited reduced overall levels of IL-10 mRNA. These data suggest that the decision whether LCMV infection becomes chronic or can be cleared critically depends on early CD4(+) T cell and monocyte/macrophage produced IL-10.
in vivo neutrophil depletion, Flow Cytometry
Garraud, K., et al. (2012). "Differential role of the interleukin-17 axis and neutrophils in resolution of inhalational anthrax" Infect Immun 80(1): 131-142. PubMed
The roles of interleukin-17 (IL-17) and neutrophils in the lung have been described as those of two intricate but independent players. Here we identify neutrophils as the primary IL-17-secreting subset of cells in a model of inhalation anthrax using A/J and C57BL/6 mice. With IL-17 receptor A knockout (IL-17RA-/-) mice, we confirmed that IL-17A/F signaling is instrumental in the self-recruitment of this population. We also show that the IL-17A/F axis is critical for surviving pulmonary infection, as IL-17RA-/- mice become susceptible to intranasal infection by Bacillus anthracis Sterne spores. Strikingly, infection with a fully virulent strain did not affect IL-17RA-/- mouse survival. Eventually, by depleting neutrophils in wild-type and IL-17RA-/- mice, we demonstrated the crucial role of IL-17-secreting neutrophils in mouse survival of infection by fully virulent B. anthracis. This work demonstrates the important roles of both IL-17 signaling and neutrophils in clearing this pathogen and surviving pulmonary B. anthracis infection.
in vivo neutrophil depletion, Flow Cytometry
Lee, W. B., et al. (2012). "Neutrophils Promote Mycobacterial Trehalose Dimycolate-Induced Lung Inflammation via the Mincle Pathway" PLoS Pathog 8(4): e1002614. PubMed
Trehalose 6,6ā²-dimycolate (TDM), a cord factor of Mycobacterium tuberculosis (Mtb), is an important regulator of immune responses during Mtb infections. Macrophages recognize TDM through the Mincle receptor and initiate TDM-induced inflammatory responses, leading to lung granuloma formation. Although various immune cells are recruited to lung granulomas, the roles of other immune cells, especially during the initial process of TDM-induced inflammation, are not clear. In this study, Mincle signaling on neutrophils played an important role in TDM-induced lung inflammation by promoting adhesion and innate immune responses. Neutrophils were recruited during the early stage of lung inflammation following TDM-induced granuloma formation. Mincle expression on neutrophils was required for infiltration of TDM-challenged sites in a granuloma model induced by TDM-coated-beads. TDM-induced Mincle signaling on neutrophils increased cell adherence by enhancing F-actin polymerization and CD11b/CD18 surface expression. The TDM-induced effects were dependent on Src, Syk, and MAPK/ERK kinases (MEK). Moreover, coactivation of the Mincle and TLR2 pathways by TDM and Pam3CSK4 treatment synergistically induced CD11b/CD18 surface expression, reactive oxygen species, and TNFalpha production by neutrophils. These synergistically-enhanced immune responses correlated with the degree of Mincle expression on neutrophil surfaces. The physiological relevance of the Mincle-mediated anti-TDM immune response was confirmed by defective immune responses in Mincle(-)/(-) mice upon aerosol infections with Mtb. Mincle-mutant mice had higher inflammation levels and mycobacterial loads than WT mice. Neutrophil depletion with anti-Ly6G antibody caused a reduction in IL-6 and monocyte chemotactic protein-1 expression upon TDM treatment, and reduced levels of immune cell recruitment during the initial stage of infection. These findings suggest a new role of Mincle signaling on neutrophils during anti-mycobacterial responses.
in vivo neutrophil depletion, Immunofluorescence
Edelson, B. T., et al. (2011). "CD8alpha(+) dendritic cells are an obligate cellular entry point for productive infection by Listeria monocytogenes" Immunity 35(2): 236-248. PubMed
CD8alpha(+) dendritic cells (DCs) prime cytotoxic T lymphocytes during viral infections and produce interleukin-12 in response to pathogens. Although the loss of CD8alpha(+) DCs in Batf3(-/-) mice increases their susceptibility to several pathogens, we observed that Batf3(-/-) mice exhibited enhanced resistance to the intracellular bacterium Listeria monocytogenes. In wild-type mice, Listeria organisms, initially located in the splenic marginal zone, migrated to the periarteriolar lymphoid sheath (PALS) where they grew exponentially and induced widespread lymphocyte apoptosis. In Batf3(-/-) mice, however, Listeria organisms remain trapped in the marginal zone, failed to traffic into the PALS, and were rapidly cleared by phagocytes. In addition, Batf3(-/-) mice, which lacked the normal population of hepatic CD103(+) peripheral DCs, also showed protection from liver infection. These results suggest that Batf3-dependent CD8alpha(+) and CD103(+) DCs provide initial cellular entry points within the reticuloendothelial system by which Listeria establishes productive infection.
in vivo neutrophil depletion
Carr, K. D., et al. (2011). "Specific depletion reveals a novel role for neutrophil-mediated protection in the liver during Listeria monocytogenes infection" Eur J Immunol 41(9): 2666-2676. PubMed
Previous studies have suggested that neutrophils are required for resistance during infection with multiple pathogenic microorganisms. However, the depleting antibody used in those studies binds to both Ly6G and Ly6C (anti-Gr-1; clone RB6-8C5). This antibody has been shown to deplete not only neutrophils but also monocytes and a subset of CD8(+) T cells. Recently, an antibody against Ly6G, which specifically depletes neutrophils, was characterized. In the present study, neutrophils are depleted using the antibody against Ly6G during infection with the intracellular bacterium Listeria monocytogenes (LM). Our data show that neutrophil-depleted mice are much less susceptible to infection than mice depleted with anti-Gr-1. Although neutrophils are required for clearance of LM, their importance is more pronounced in the liver and during a high-dose bacterial challenge. Furthermore, we demonstrate that the protection mediated by neutrophils is due to the production of TNF-alpha, but not IFN-gamma. Additionally, neutrophils are not required for the recruitment of monocytes or the generation of adaptive T-cell responses during LM infection. This study highlights the importance of neutrophils during LM infection, and indicate that depletion of neutrophils is less detrimental to the host than depletion of all Gr-1-expressing cell populations.
in vivo neutrophil depletion, Flow Cytometry
Bamboat, Z. M., et al. (2010). "Conventional DCs reduce liver ischemia/reperfusion injury in mice via IL-10 secretion" J Clin Invest 120(2): 559-569. PubMed
TLRs are recognized as promoters of tissue damage, even in the absence of pathogens. TLR binding to damage-associated molecular patterns (DAMPs) released by injured host cells unleashes an inflammatory cascade that amplifies tissue destruction. However, whether TLRs possess the reciprocal ability to curtail the extent of sterile inflammation is uncertain. Here, we investigated this possibility in mice by studying the role of conventional DCs (cDCs) in liver ischemia/reperfusion (I/R) injury, a model of sterile inflammation. Targeted depletion of mouse cDCs increased liver injury after I/R, as assessed by serum alanine aminotransferase and histologic analysis. In vitro, we identified hepatocyte DNA as an endogenous ligand to TLR9 that promoted cDCs to secrete IL-10. In vivo, cDC production of IL-10 required TLR9 and reduced liver injury. In addition, we found that inflammatory monocytes recruited to the liver via chemokine receptor 2 were downstream targets of cDC IL-10. IL-10 from cDCs reduced production of TNF, IL-6, and ROS by inflammatory monocytes. Our results implicate inflammatory monocytes as mediators of liver I/R injury and reveal that cDCs respond to DAMPS during sterile inflammation, providing the host with protection from progressive tissue damage.
- Cardiovascular biology,
- Immunology and Microbiology
Periodontitis aggravates pulmonary fibrosis by Porphyromonas gingivalis-promoted infiltration of neutrophils and Th17 cells.
In Frontiers in Cellular and Infection Microbiology on 11 June 2025 by Ye, H. L., Meng, X. Q., et al.
Idiopathic pulmonary fibrosis (IPF) is a fatal interstitial lung disease. However, the pathogeny of IPF is poorly understood, and therapeutic options are very limited. Periodontitis (PD) is a chronic inflammatory disease that leads to dysbiosis of both the oral microbiome and host immune responses. While previous studies have suggested a PD-IPF association, insights into the mechanisms remain limited. The PD mouse model was established by the ligation of molars and oral inoculation of subgingival plaques from PD patients and subsequently incorporated with a bleomycin-induced pulmonary fibrosis model. The effect of PD on pulmonary fibrosis was determined. Changes of immune cells were analysed using flow cytometry. Moreover, the microbiome changes of the lungs and oral cavity were assessed by 16S rRNA gene sequencing and fluorescence in situ hybridization. Finally, the effect and mechanism of the specific PD pathogen on pulmonary fibrosis were determined. PD significantly aggravated pulmonary fibrosis in mice by increasing the infiltration of neutrophils and Th17 cells. Neutrophils and Th17 cells are critical in PD-induced aggravation of pulmonary fibrosis, and Th17 cells regulate neutrophils via IL-17A. The PD pathogen Porphyromonas gingivalis (Pg) was detected enriched in both the oral cavity and lungs. Pg was further determined to exacerbate pulmonary fibrosis by increasing the expansion of neutrophils and Th17 cells in mice. PD aggravates pulmonary fibrosis in mice, which is likely induced by Pg-promoted infiltration of neutrophils and Th17 cells. Treatment targeting PD or Pg might be a promising strategy to clinically ameliorate IPF. Copyright Ā© 2025 Ye, Meng, Li, Sun, Lin, Zhou, Zhang, Hou, Xu, Chen, Qiu, Li, Wang, Yan and Duan.
- Neuroscience
Astrocyte-derived CCL5-mediated CCR5+ neutrophil infiltration drives depression pathogenesis.
In Science Advances on 23 May 2025 by Yao, H., Jiang, S. Y., et al.
Cross-talk between the nervous and immune systems is involved in neurological diseases. However, their potential interplay in depression has yet to be elucidated. Here, using single-cell RNA and neutrophil SMART RNA sequencing, we showed that CCR5+ neutrophils were significantly increased in patients with depression and preferentially migrated to the hippocampus in a mouse model of depression. Infiltrated neutrophils engulf neuronal spines and subsequently promote depressive symptoms in male mice. Furthermore, by genetic or pharmacologic disruption, we identified a chemotactic effect of the astrocyte-derived chemokine CCL5 on mediating the infiltration of CCR5+ neutrophils and behavioral disorders in male depressed mice. Our findings therefore highlight the critical role of neutrophils in depression pathogenesis and astrocytes in mediating the dysregulation of innate immune responses and suggest that inhibition of CCL5/CCR5-mediated neutrophil infiltration represents a potential therapeutic strategy for noninfectious brain diseases such as depression.
- In Vivo,
- Mus musculus (House mouse),
- Immunology and Microbiology
Caspase-1-licensed pyroptosis drives dsRNA-mediated necroptosis and dampens host defense against bacterial pneumonia.
In PLoS Pathogens on 1 May 2025 by Luo, Q., Shen, L., et al.
Bacterial lung infections cause severe host responses. Here, we showed that global deficiency of caspase-1 can protect against lethal pulmonary Escherichia coli infection by reducing the necroptosis of infiltrated neutrophils, which are key players in immune responses in the lung. Mechanistically, neutrophil necroptosis was not directly triggered in a cell-intrinsic manner by invading bacteria but was triggered by bacteria-stimulated pyroptotic epithelial cell supernatants in vitro. In validation experiments, chimeric mice with nonhematopoietic caspase-1 or GSDMD knockout were protected from lung E. coli infection and exhibited decreased neutrophil death. Nonhematopoietic pyroptosis facilitates the release of dsRNAs and contributes to neutrophil ZBP1-related necroptosis. Moreover, blocking dsRNA or depleting ZBP1 ameliorated the pathophysiological process of pulmonary E. coli infection. Overall, our results demonstrate a paradigm of communication between necroptosis and pyroptosis in different cell types in cooperation with microbes and hosts and suggest that therapeutic targeting of the pyroptosis or necroptosis pathway may prevent pulmonary bacterial infection. Copyright: Ā© 2025 Luo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
- Endocrinology and Physiology
NETs activate the GAS6-AXL-NLRP3 axis in macrophages to drive morphine tolerance.
In Cell Communication and Signaling : CCS on 11 April 2025 by Tian, Q., Guo, H., et al.
The development of morphine tolerance presents a major clinical challenge in the effective management of severe pain. This study aims to explore the mechanisms underlying morphine tolerance from a novel perspective, with the ultimate goal of uncovering new insights and identifying promising therapeutic targets for its treatment. C57BL/6J mice were used in the tail-flick test to evaluate morphine tolerance. Neutrophils derived from mouse bone marrow were employed to investigate the mechanisms underlying morphine-induced NETs formation. Bone marrow-derived macrophages (BMDMs) were harvested from the femur and tibia to study the role of NETs-induced inflammation in analgesic tolerance. Proinflammatory cytokines were measured using Western blotting and real-time PCR. The levels of NETs and the TLR7/9-NLRP3-related signaling pathway were assessed through Western blotting, real-time PCR, and ELISA. Confocal laser scanning microscopy was utilized to visualize NETs in the dorsal root ganglion (DRG) and in cells. Our experiments demonstrated that the levels of NETs in the plasma of patients using morphine for analgesia, as well as in morphine-tolerant animals, were significantly elevated. Genetic elimination of Pad4, neutrophil depletion, and treatment with DNase 1 and RNase A to disrupt NETs formation all effectively alleviated morphine tolerance. These findings indicate that NETs play a critical role in the development of morphine tolerance. Mechanistically, we discovered that morphine-induced NETs can be engulfed by macrophages through the GAS6-AXL axis, which subsequently triggers the activation of the TLR7/TLR9-mediated NLRP3 inflammasome, leading to significantly increased levels of IL-1Ī² and IL-18, and ultimately contributing to tolerance. Deletion of Axl, Gas6, or Nlrp3 each significantly improved morphine tolerance. Furthermore, in the murine model, treatment with the IL-1 receptor antagonist anakinra and the IL-18 decoy receptor IL-18BP prevented the development of morphine tolerance. This study identifies morphine-induced NETs as a key contributor to morphine tolerance, with the GAS6-AXL-TLR7/9 axis emerging as a potential therapeutic target. Strategies focused on disrupting NETs and modulating this axis may offer a promising approach to combat morphine tolerance. Ā© 2025. The Author(s).
- Mus musculus (House mouse),
- Cancer Research
Lenvatinib-activated NDUFA4L2/IL33/PADI4 pathway induces neutrophil extracellular traps that inhibit cuproptosis in hepatocellular carcinoma.
In Cellular Oncology (Dordrecht) on 1 April 2025 by Yi, N., Zhang, L., et al.
Lenvatinib is a potent first-line therapy for patients with hepatocellular carcinoma (HCC), but it also increased the number of neutrophils in HCC tumor microenvironment. CitH3, MPO-DNA, elastase and MPO activity were measured for assessing neutrophil extracellular traps (NETs) in vivo and in vitro. Cell cuproptosis was assessed by measurement of copper content, FDX1, and pyruvate. The functions of lenvatinib, DNase I, interleukin 33 (IL33) neutralizing antibody and GPX4 in tumor growth were explored in mice. Lenvatinib induced NETs in the HCC tumor microenvironment via HCC cells, but not through the direct stimulation of neutrophils. In addition, NET clearance by DNase I improves the efficacy of lenvatinib therapy in HCC mouse models. Mechanistically, lenvatinib promoted the expression and secretion of IL33 by HCC cells that triggered NET formation. Moreover, IL33 knockdown in Hepa1-6 cells improved lenvatinib efficacy in Hepa1-6-bearing HCC model mice and reduced NET formation in the tumor microenvironment. Subsequently, lenvatinib increased IL33 production by increasing the NDUFA4L2 expression in HCC cells. Furthermore, we found that IL33 triggered NET formation in neutrophils by increasing the protein expression of PADI4 via the Akt/mTOR signaling pathway. Rapamycin inhibition of mTOR reduced PADI4 expression and NET formation. Consistently, PADI4 inhibition by the selective PAD4 inhibitor GSK484 hydrochloride (GSK484) improved lenvatinib response to HCC therapy. Importantly, NETs contribute to lenvatinib resistance by inhibiting cuproptosis, but not apoptosis, pyroptosis, or ferroptosis in HCC cells. Treatment with GSK484 reversed the inhibitory effects of NETs on cuproptosis and sensitized the HCC cells to lenvatinib. Our study revealed that lenvatinib-induced NETs inhibited the cuproptosis of HCC cells, suggesting that targeting the IL33/PADI4/NET axis represents a promising therapeutic strategy for ameliorating lenvatinib resistance in HCC. Ā© 2024. The Author(s).
- Biochemistry and Molecular biology
Neutrophil Depletion Reduced the Relative Abundance of Unsaturated Long-Chain Fatty Acid Synthesis Microbiota and Intestinal Lipid Absorption.
In Cell Biochemistry and Function on 1 April 2025 by Lu, X., Xu, Y., et al.
As immune cells, neutrophils serve as the first line of defense against infections; however, the mechanism by which neutrophils regulate lipid metabolism is unknown. The neutrophil depletion group was treated with 100āĪ¼g InVivoMAb anti-mouse Ly6G 6 times, whereas the control group mice were intraperitoneally injected with the same quantity of InVivoMAb rat IgG2a. Body fat content, triglycerides (TGs), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) in the jejunum and ileum, as well as 9 long-chain fatty acids (LCFAs) in the intestinal contents were significantly decreased. Furthermore, genes involved in the absorption of lipids in each segment of the intestine also showed decreased expression. Neutrophil-depletion and control models were administered 25āĪ¼Ci of 3H-cholesterol by gavage. The distribution of 3H cholesterol in the intestinal segment, heart, liver, serum, and feces was not altered by anti-Ly6G antibodies. Metagenomics was applied to investigate uncultured microorganisms in the intestinal contents to identify bacteria containing lipid metabolism genes. At the species level, 12 bacteria were involved in unsaturated LCFA synthesis, among which 2 increased and 10 decreased. The overall relative abundance of these bacteria decreased from 3.102% to 0.734%. Many genes involved in lipid metabolism were also reduced as a result, such as fatty acid synthase and peroxisome proliferator-activated receptor Ī³. In conclusion, neutrophil depletion does not affect intestinal lipid absorption in the diet but leads to a decrease in the overall relative abundance of gut bacteria involved in unsaturated LCFA synthesis. Consequently, intestinal lipid synthesis and absorption are reduced. Ā© 2025 John Wiley & Sons Ltd.
- Mus musculus (House mouse)
Protective effects of indole-3-propionic acid against TCP-induced hearing loss in mice by mitigating oxidative stress and promoting neutrophil recruitment.
In Scientific Reports on 19 March 2025 by Mao, S., Zhang, Z., et al.
Sensorineural hearing loss (SNHL) poses a significant global health challenge with substantial socioeconomic and medical implications. The pathophysiology involves excessive reactive oxygen species (ROS) in the cochlea, inflammation, cellular apoptosis, etc. Tryptophan metabolite indole-3-propionic Acid (IPA), produced by gut microbiota, may offer therapeutic benefits by modulating inflammation, oxidative stress, and immune responses. However, the roles of IPA in protecting from treatment hearing loss in adult mice remain to be investigated. We previously validated that exposure to pesticide metabolite 3, 5, 6-Trichloro-2-pyridinol (TCP) caused hearing loss in mice. Herein, continuous administration of 40Ā mg/kg IPA for 21 days significantly attenuated the hearing threshold elevation in C57BL/6 mice exposed to 50Ā mg/kg TCP. IPA treatment reduced the loss of hair cells (HCs) and spiral ganglion neurons (SGNs), preserved nerve fibers, and reversed the damage to spiral ligaments (SL) and stria vascularis (SV). Similarly, IPA cotreatment decreased ROS accumulation in the cochlea and inhibited HC and SGN apoptosis. Transcriptomic analysis showed that IPA enhanced immune responses, particularly through neutrophil recruitment and the activation of regenerative signals like IFNĪ³. These findings underscore IPA's protective effects against TCP-induced hearing loss, highlighting the role of immune mechanisms in cochlear protection. Ā© 2025. The Author(s).
- FC/FACS,
- Mus musculus (House mouse),
- Biochemistry and Molecular biology,
- Cell Biology,
- Immunology and Microbiology
Reprogramming aerobic metabolism mitigates Streptococcus pyogenes tissue damage in a mouse necrotizing skin infection model.
In Nature Communications on 15 March 2025 by Xu, W., Bradstreet, T. R., et al.
Disease tolerance is a host response to infection that limits collateral damage to host tissues while having a neutral effect on pathogen fitness. Previously, we found that the pathogenic lactic acid bacterium Streptococcus pyogenes manipulates disease tolerance using its aerobic mixed-acid fermentation pathway via the enzyme pyruvate dehydrogenase, but the microbe-derived molecules that mediate communication with the host's disease tolerance pathways remain elusive. Here we show in a murine model that aerobic mixed-acid fermentation inhibits the accumulation of inflammatory cells including neutrophils and macrophages, reduces the immunosuppressive cytokine interleukin-10, and delays bacterial clearance and wound healing. In infected macrophages, the aerobic mixed-acid fermentation end-products acetate and formate from streptococcal upregulate host acetyl-CoA metabolism and reduce interleukin-10 expression. Inhibiting aerobic mixed-acid fermentation using a bacterial-specific pyruvate dehydrogenase inhibitor reduces tissue damage during murine infection, correlating with increased interleukin-10 expression. Our results thus suggest that reprogramming carbon flow provides a therapeutic strategy to mitigate tissue damage during infection. Ā© 2025. The Author(s).
- In Vivo,
- Mus musculus (House mouse),
- Immunology and Microbiology
Discrete and conserved inflammatory signatures drive thrombosis in different organs after Salmonella infection.
In Nature Communications on 10 March 2025 by Perez-Toledo, M., Beristain-Covarrubias, N., et al.
Inflammation-induced thrombosis is a common consequence of bacterial infections, such as those caused by Salmonella Typhimurium (STm). The presentation of multi-organ thrombosis post-infection that develops and resolves with organ-specific kinetics raises significant challenges for its therapeutic control. Here, we identify specific inflammatory events driving thrombosis in the spleens and livers of STm-infected mice. IFN-Ī³ or platelet expression of C-type lectin-like receptor CLEC-2, key drivers of thrombosis in liver, are dispensable for thrombosis in the spleen. Platelets, monocytes, and neutrophils are identified as core constituents of thrombi in both organs. Depleting either neutrophils or monocytic cells abrogates thrombus formation. Neutrophils and monocytes secrete TNF and blocking TNF diminishes both thrombosis and inflammation, which correlates with reduced endothelial expression of E-selectin and leukocyte infiltration. Moreover, inhibiting tissue factor and P-selectin glycoprotein ligand-1 pathways impairs thrombosis in both spleen and liver. Therefore, we identify organ-specific, and shared mechanisms driving thrombosis within a single infection. This may inform on tailoring treatments towards infection-induced inflammation, and single- or multi-organ thrombosis, based on the clinical need. Ā© 2025. The Author(s).
- Neuroscience
Neutrophil stalling does not mediate the increase in tau phosphorylation and the cognitive impairment associated with high salt diet
Preprint on BioRxiv : the Preprint Server for Biology on 4 March 2025 by Ahn, S., Goya, B., et al.
ABSTRACT High dietary salt intake has powerful effects on cerebral blood vessels and has emerged as a risk factor for stroke and cognitive impairment. In mice, high salt diet (HSD) leads to reduced cerebral blood flow (CBF), tau hyperphosphorylation and cognitive dysfunction. However, it is still unclear whether the reduced CBF is responsible for the effects of HSD on tau and cognition. Capillary stalling has emerged as a cause of CBF reduction and cognitive impairment in models of Alzheimerās disease and diabetes. Therefore, we tested the hypothesis that capillary stalling also contributes to the CBF reduction and cognitive impairment in HSD. Using two-photon imaging, we found that HSD increased stalling of neutrophils in brain capillaries and decreased CBF. Neutrophil depletion reduced the number of stalled capillaries and restored resting CBF but did not prevent tau phosphorylation or cognitive impairment. These novel findings show that, capillary stalling contribute to CBF reduction in HSD, but not to tau phosphorylation and cognitive deficits. Therefore, the hypoperfusion caused by capillary stalling is not the main driver of the tau phosphorylation and cognitive impairment.
- Cancer Research
Neutrophil extracellular traps impede cancer metastatic seeding via protease-activated receptor 2-mediated downregulation of phagocytic checkpoint CD24.
In Journal for Immunotherapy of Cancer on 26 February 2025 by Liu, Y., Ma, J., et al.
Phagocytic clearance by macrophages represents a critical immune surveillance mechanism in cancer liver metastasis. Neutrophils, the most abundant immune cells encountered by cancer cells in circulation, play key roles in metastasis through neutrophil extracellular traps (NETs). Although NETs promote macrophage phagocytosis during infection, whether they regulate phagocytosis during cancer metastasis is unknown. The present study aimed to explore the roles of NETs in regulating macrophage phagocytosis during the seeding process of liver metastasis and the mechanisms underlying the roles. A lipopolysaccharide-induced NET model was applied to study the role of NETs on colorectal cancer (CRC) liver metastasis. The neutrophils isolated from human peripheral blood were stimulated with PMA to release NETs, which were collected and added to the cultures of different CRC cell lines for in vitro studies. Macrophage phagocytosis was assessed with flow cytometry in vitro and in vivo. RNA-seq and microRNA array analyses were performed to identify key pathways regulated by NETs and downstream key molecules. The macrophage phenotypes were evaluated using immunohistochemistry, flow cytometry, and cytokine and chemokine arrays. NETs promote macrophage phagocytosis both in vitro and in vivo. Neutrophil elastase (NE), which was able to inactivate the canonical signal of protease-activated receptor 2 (PAR2), downregulated the phagocytotic checkpoint CD24. Notably, PAR2 deficiency imitated the effect of NETs on phagocytosis and CD24. Mechanistic studies indicated that inhibiting PAR2 expression upregulated miR-34a and miR-146a and downregulated CD24 in cancer cells. In addition, PAR2 depletion enhanced the recruitment and M1 polarization of macrophages by upregulating CSF-1 and CXCL1. The correlation of NETs/NE and CD24 was corroborated using human CRC specimens. Furthermore, PAR2 blockade combined with an anti-EGFR antibody (cetuximab (CTX)) synergistically enhanced the phagocytic ability of macrophages and suppressed liver metastasis in vivo. NET-derived elastase inactivated PAR2 canonical signaling and promoted phagocytosis by downregulating CD24, which functions as a phagocytotic checkpoint in CRC liver metastasis. Thus, PAR2 inhibitors combined with CTX may serve as a novel therapeutic strategy against advanced CRC. Ā© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.
- In Vivo,
- Mus musculus (House mouse),
- Immunology and Microbiology
Effects of injury size on local and systemic immune cell dynamics in volumetric muscle loss.
In Npj Regenerative Medicine on 13 February 2025 by Whitaker, R., Sung, S., et al.
We took a systems approach to the analysis of macrophage phenotype in regenerative and fibrotic volumetric muscle loss outcomes in mice together with analysis of systemic inflammation and of other leukocytes in the muscle, spleen, and bone marrow. Differences in expression of macrophage phenotype markers occurred as early as day 1, persisted to at least day 28, and were associated with increased numbers of leukocytes in the muscle and bone marrow, increased pro-inflammatory marker expression in splenic macrophages, and changes in the levels of pro-inflammatory cytokines in the blood. The most prominent differences were in muscle neutrophils, which were much more abundant in fibrotic outcomes compared to regenerative outcomes at day 1 after injury. However, neutrophil depletion had little to no effect on macrophage phenotype or on muscle repair outcomes. Together, these results suggest that the entire system of immune cell interactions must be considered to improve muscle repair outcomes. Ā© 2025. The Author(s).
- Mus musculus (House mouse),
- Immunology and Microbiology
IÄøBĪ¶ as a Central Modulator of Inflammatory Arthritis Pathogenesis.
In Arthritis Rheumatology (Hoboken, N.J.) on 1 February 2025 by Swarnkar, G., Naaz, M., et al.
Current therapies targeting individual factors in inflammatory arthritis show variable efficacy, often requiring treatment with combinations of drugs, and are associated with undesirable side effects. NF-ÄøB is critical for the production and function of most inflammatory cytokines. However, given its essential role in physiologic processes, targeting NF-ÄøB is precarious. Hence, identifying pathways downstream of NF-ÄøB that selectively govern the expression of inflammatory cytokines in inflammatory arthritis would be advantageous. We have previously identified IÄøBĪ¶ as a unique inflammatory signature of NF-ÄøB that controls the transcription of inflammatory cytokines only under pathologic conditions while sparing physiologic NF-ÄøB signals. We generated mice harboring myeloid, lymphoid, and global deletion of Nfkbiz (the gene encoding IÄøBĪ¶). These models were subjected to serum transfer-induced arthritis. Additionally, pharmacologic inhibitors of IÄøBĪ¶ were injected intraperitonially. Joint swelling, microcomputed tomography, immunohistochemistry, flow cytometry, and cytokine measurements were conducted using synovial tissue samples. Global deletion of Nfkbiz or depletion of neutrophils (vastly IÄøBĪ¶+ cells) reduced inflammatory synovial cells and increased anti-inflammatory and regenerative synovial cells, plummeted expression of inflammatory factors and ameliorated experimental mouse inflammatory arthritis. Further, expression of immune responsive gene-1, the enzyme responsible for itaconate production, was increased in synovial cells. Accordingly, the itaconate derivative dimethyl itaconate (DI) inhibited IÄøBĪ¶-mediated inflammatory factors. Further, in silico screen identified 8-hydroxyquinoline (HQ) as a putative inhibitor of IÄøBĪ¶ not affecting physiologic NF-ÄøB activity. Congruently, systemic administration of either DI or HQ inhibited joint swelling and damage. Our study positions IÄøBĪ¶ as an inflammation-specific target for therapeutic consideration in rheumatoid arthritis because its inhibition spares the beneficial functions of NF-ÄøB. Ā© 2024 American College of Rheumatology.
- Cancer Research
Ferroptotic Neutrophils Induce Immunosuppression and Chemoresistance in Breast Cancer.
In Cancer Research on 1 February 2025 by Zeng, W., Zhang, R., et al.
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 IL1Ī²+CXCL3+CD4+ (Fer-CD4) T lymphocytes, which were enriched in chemoresistant tumors. Fer-CD4 T cells orchestrated neutrophil ferroptosis by modulating MOAT1 expression via IL1Ī²/IL1R1/NF-ĪŗB 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 IL1Ī²+ 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, IL1Ī²+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. Ā©2024 The Authors; Published by the American Association for Cancer Research.
- Mus musculus (House mouse)
Macrophages orchestrate elimination ofShigellafrom the intestinal epithelial cell niche via TLR-induced IL-12 and IFN-Ī³
Preprint on BioRxiv : the Preprint Server for Biology on 22 January 2025 by Eislmayr, K. D., Langner, C., et al.
Bacteria of the genus Shigella replicate in intestinal epithelial cells and cause shigellosis, a severe diarrheal disease that resolves spontaneously in most healthy individuals. During shigellosis, neutrophils are abundantly recruited to the gut, and have long been thought to be central to Shigella control and pathogenesis. However, how shigellosis resolves remains poorly understood due to the longstanding lack of a tractable and physiological animal model. Here, using our newly developed Nlrc4 ā/ā Casp11 ā/ā mouse model of shigellosis, we unexpectedly find no major role for neutrophils in limiting Shigella or in disease pathogenesis. Instead, we uncover an essential role for macrophages in the host control of Shigella . Macrophages respond to Shigella via TLRs to produce IL-12, which then induces IFN-Ī³, a cytokine that is essential to control Shigella replication in intestinal epithelial cells. Collectively, our findings reshape our understanding of the innate immune response to Shigella .
- Cardiovascular biology,
- Immunology and Microbiology,
- Neuroscience
Microglial NLRP3-gasdermin D activation impairs blood-brain barrier integrity through interleukin-1Ī²-independent neutrophil chemotaxis upon peripheral inflammation in mice.
In Nature Communications on 15 January 2025 by Yoon, S. H., Kim, C. Y., et al.
Blood-brain barrier (BBB) disintegration is a key contributor to neuroinflammation; however, the biological processes governing BBB permeability under physiological conditions remain unclear. Here, we investigate the role of NLRP3 inflammasome in BBB disruption following peripheral inflammatory challenges. Repeated intraperitoneal lipopolysaccharide administration causes NLRP3-dependent BBB permeabilization and myeloid cell infiltration into the brain. Using a mouse model with cell-specific hyperactivation of NLRP3, we identify microglial NLRP3 activation as essential for peripheral inflammation-induced BBB disruption. Conversely, NLRP3 and microglial gasdermin D (GSDMD) deficiency markedly attenuates lipopolysaccharide-induced BBB breakdown. Notably, IL-1Ī² is not required for NLRP3-GSDMD-mediated BBB disruption. Instead, microglial NLRP3-GSDMD axis upregulates CXCL chemokines and matrix metalloproteinases around BBB via producing GDF-15, promoting the recruitment of CXCR2-containing neutrophils. Inhibition of neutrophil infiltration and matrix metalloproteinase activity significantly reduces NLRP3-mediated BBB impairment. Collectively, these findings reveal the important role of NLRP3-driven chemokine production in BBB disintegration, suggesting potential therapeutic targets to mitigate neuroinflammation. Ā© 2025. The Author(s).
- Immunology and Microbiology
FAP-targeted radioligand therapy with 68Ga/177Lu-DOTA-2P(FAPI)2 enhance immunogenicity and synergize with PD-L1 inhibitors for improved antitumor efficacy.
In Journal for Immunotherapy of Cancer on 11 January 2025 by Chen, J., Zhou, Y., et al.
Fibroblast activation protein (FAP)-targeted radioligand therapy, with immunomodulatory effects, has shown efficacy in both preclinical and clinical studies. We recently reported on a novel dimeric FAP-targeting radiopharmaceutical, 68Ga/177Lu-DOTA-2P(FAPI)2, which demonstrated increased tumor uptake and prolonged retention in various cancers. However, further exploration is required to understand the therapeutic efficacy and underlying mechanisms of combining 68Ga/177Lu-DOTA-2P(FAPI)2 radioligand therapy with PD-1/PD-L1 immunotherapy. Regarding the change in PD-L1 expression and DNA double-strand breaks induced by radiopharmaceuticals, CT26-FAP tumor cells were incubated with 68Ga and 177Lu labeled DOTA-2P(FAPI)2, respectively. Monotherapy with 68Ga-DOTA-2P(FAPI)2, 177Lu-DOTA-2P(FAPI)2, and PD-L1 immunotherapy as well as combination therapy (68Ga/177Lu-DOTA-2P(FAPI)2 and PD-L1 immunotherapy) were tested and evaluated to evaluate in vivo antitumor efficacy. Furthermore, immunohistochemical staining and single-cell RNA sequencing were used to analyze changes in the tumor microenvironment (TME) and elucidate the underlying mechanisms of action of this combination therapy. Our findings indicated that FAP-targeting radiopharmaceuticals can induce DNA double-strand breaks and upregulate PD-L1 expression, with 177Lu-DOTA-2P(FAPI)2 proving to be more effective than 68Ga-DOTA-2P(FAPI)2. Both 68Ga-DOTA-2P(FAPI)2 and 177Lu-DOTA-2P(FAPI)2 radiopharmaceuticals significantly improved therapeutic outcomes when combined with anti-PD-L1 monoclonal antibody (Ī±PD-L1 mAb). Notably, the combination of 177Lu-DOTA-2P(FAPI)2 with Ī±PD-L1 mAb immunotherapy eliminated tumors in mouse models. Mice treated with this regimen not only exhibited exceptional responses to the initial immune checkpoint inhibitor therapy but also showed 100% tumor rejection on subsequent tumor cell re-inoculation. Further mechanistic studies have shown that 177Lu-DOTA-2P(FAPI)2 combined with Ī±PD-L1 mAb can reprogram the TME, enhancing antitumor intercellular communication, which activates antitumor-related intercellular contacts such as FasL-Fas interactions between T cells and NK cells with tumor cells and increasing the proportion of infiltrating CD8+ T-cells while reducing regulatory T cells and inhibiting tumor progression. Our research also demonstrates that mature neutrophils play a role in enhancing the efficacy of the combined therapy, as shown in neutrophil-blocking experiments. Our study robustly advocates for use of FAP-targeting radiopharmaceuticals, particularly 177Lu-DOTA-2P(FAPI)2, alongside immunotherapy in treating FAP-positive tumors. This combination therapy transforms the TME and enables a translatable approach to increasing the sensitivity to PD-1/PD-L1 immunotherapy, leading to improved complete remission rates and extended overall survival. Ā© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.
- Cancer Research,
- Immunology and Microbiology
Inhibition of the chemokine receptors CXCR1 and CXCR2 synergizes with docetaxel for effective tumor control and remodeling of the immune microenvironment of HPV-negative head and neck cancer models.
In Journal of Experimental & Clinical Cancer Research : CR on 5 December 2024 by Horn, L. A., Lind, H., et al.
Relapsed head and neck squamous cell carcinoma (HNSCC) unrelated to HPV infection carries a poor prognosis. Novel approaches are needed to improve the clinical outcome and prolong survival in this patient population which has poor long-term responses to immune checkpoint blockade. This study evaluated the chemokine receptors CXCR1 and CXCR2 as potential novel targets for the treatment of HPV-negative HNSCC. Expression of IL-8, CXCR1, and CXCR2 was investigated in HNSCC tissues and human cell line models. Inhibition of CXCR1/2 with the clinical stage, small molecule inhibitor, SX-682, was evaluated in vitro and in vivo using human xenografts and murine models of HNSCC, both as a monotherapy and in combination with the taxane chemotherapy, docetaxel. High levels of IL-8, CXCR1, and CXCR2 expression were observed in HPV-negative compared to HPV-positive HNSCC tumors or cell lines. Treatment of HPV-negative HNSCC cell lines in vitro with SX-682 sensitized the tumor cells to the cytotoxic activity of docetaxel. In vivo, treatment of HNSCC xenograft models with the combination of SX-682 plus docetaxel led to strong anti-tumor control resulting in tumor cures. This phenomenon was associated with an increase of microRNA-200c and a decreased expression of its target, tubulin beta-3, a protein involved in resistance to microtubule-targeting chemotherapies. In vivo treatment of a murine syngeneic model of HNSCC with SX-682 plus docetaxel led to potent anti-tumor efficacy through a simultaneous decrease in suppressive CXCR2+ polymorphonuclear, myeloid-derived suppressor cells and an increase in cytotoxic CD8+ T cells in the combination therapy treated tumors compared to controls. This study reports, for the first time, mechanistic findings through which the combination of CXCR1/2 inhibition and docetaxel chemotherapy exhibits synergy in models of HPV-negative HNSCC. These findings provide rationale for the use of this novel combination approach to treat HPV-negative HNSCC patients and for future combination studies of CXCR1/2 inhibition, docetaxel, and immune-based therapies. Ā© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.
- In Vivo,
- Mus musculus (House mouse),
- Cancer Research
Targeting SPP1-orchestrated neutrophil extracellular traps-dominant pre-metastatic niche reduced HCC lung metastasis.
In Experimental Hematology Oncology on 11 November 2024 by Xie, S. Z., Yang, L. Y., et al.
The mechanisms by which tumor-derived factors remodel the microenvironment of target organs to facilitate cancer metastasis, especially organ-specific metastasis, remains obscure. Our previous studies have demonstrated that SPP1 plays a key role in promoting metastasis of hepatocellular carcinoma (HCC). However, the functional roles and mechanisms of tumor-derived SPP1 in shaping the pre-metastatic niche (PMN) and promoting lung-specific metastasis are unclear. Orthotopic metastasis models, experimental metastasis models, CyTOF and flow cytometry were conducted to explore the function of SPP1 in shaping neutrophil-dominant PMN and promoting HCC lung metastasis. The main source of CXCL1 in lung tissues was investigated via fluorescence activated cell sorting and immunofluorescence staining. The expression of neutrophils and neutrophil extracellular traps (NETs) markers was detected in the lung metastatic lesions of HCC patients and mouse lung specimens. The therapeutic significance was explored via in vivo DNase I and CXCR2 inhibitor assays. SPP1 promoted HCC lung colonization and metastasis by modifying pulmonary PMN in various murine models, and plasma SPP1 levels were closely associated with lung metastasis in HCC patients. Mechanistically, SPP1 binded to CD44 on lung alveolar epithelial cells to produce CXCL1, thereby attracting and forming neutrophil-abundant PMN in the lung. The recruited neutrophils were activated by SPP1 and then formed NETs-dominant PMN to trap the disseminated tumor cells and promote metastatic colonization. Moreover, early intervention of SPP1-orchestrated PMN by co-targeting the CXCL1-CXCR2 axis and NETs formation could efficiently inhibit the lung metastasis of HCC. Our study illustrates that HCC-lung host cell-neutrophil interactions play important roles in PMN formation and SPP1-induced HCC lung metastasis. Early intervention in SPP1-orchestrated PMN via CXCR2 inhibitor and DNase I is a potential therapeutic strategy to combat HCC lung metastasis. Ā© 2024. The Author(s).
- Immunology and Microbiology,
- Stem Cells and Developmental Biology
Dermal TRPV1 innervations engage a macrophage- and fibroblast-containing pathway to activate hair growth in mice.
In Developmental Cell on 4 November 2024 by Ben-Shaanan, T. L., Knƶpper, K., et al.
Pain, detected by nociceptors, is an integral part of injury, yet whether and how it can impact tissue physiology and recovery remain understudied. Here, we applied chemogenetics in mice to locally activate dermal TRPV1 innervations in naive skin and found that it triggered new regenerative cycling by dormant hair follicles (HFs). This was preceded by rapid apoptosis of dermal macrophages, mediated by the neuropeptide calcitonin gene-related peptide (CGRP). TRPV1 activation also triggered a macrophage-dependent induction of osteopontin (Spp1)-expressing dermal fibroblasts. The neuropeptide CGRP and the extracellular matrix protein Spp1 were required for the nociceptor-triggered hair growth. Finally, we showed that epidermal abrasion injury induced Spp1-expressing dermal fibroblasts and hair growth via a TRPV1 neuron and CGRP-dependent mechanism. Collectively, these data demonstrated a role for TRPV1 nociceptors in orchestrating a macrophage and fibroblast-supported mechanism to promote hair growth and enabling the efficient restoration of this mechano- and thermo-protective barrier after wounding. Copyright Ā© 2024 The Authors. Published by Elsevier Inc. All rights reserved.
