Atherosclerotic plaque destabilization is promoted by inflammatory cell recruitment, tissue cell death, and mechanical weakening. Neutrophils drive vascular tissue injury and perpetuate inflammation and represent a viable therapeutic opportunity. Here, we identify a distinct subset of activated neutrophils within atherosclerotic lesions that express the chemokine receptor CCR2 (C-C chemokine receptor type 2), which directs their migration toward areas enriched with smooth muscle cells and contributes to plaque instability. Flow cytometry and single-cell transcriptomic analysis of CCR2+ neutrophils within murine and human atherosclerotic plaques. Tracking of CCR2+ neutrophil in hypercholesterolemic Ldlr-/- mice and in mice reconstituted with Ccr2GFP/- bone marrow. In vivo reactive oxygen species and neutrophil extracellular trap analysis in lipopolysaccharide-induced peritonitis. In vitro migration assays of neutrophils deficient for or treated with a specific antagonist against chemokine receptors. In vivo neutrophil recruitment and features of atherosclerotic plaque vulnerability analysis on CCR2 and CCL2 (C-C motif chemokine ligand 2) blockade in a model of advanced atherosclerosis in Apoe-/- mice. CCR2+ neutrophils preferentially populate mouse and human atherosclerotic lesions and display a proinflammatory phenotype with enhanced capacity for reactive oxygen species production and neutrophil extracellular trap release. Genetic or pharmacological CCR2 inhibition reduced neutrophil migration and infiltration to the atherosclerotic lesion, reducing their presence in smooth muscle cell-rich areas. Consistently, neutralization of the CCR2 ligand CCL2 decreased lesional neutrophil numbers and preserved fibrous cap integrity by increasing smooth muscle cell content and decreasing features associated with plaque instability. Our data suggest that a subset of CCR2-expressing neutrophils senses smooth muscle cell-derived CCR2 ligands to infiltrate and promote vulnerable atherosclerotic lesions. These results support that neutrophil functional heterogeneity within the atherosclerotic lesions alters lesion stability. Specific targeting thereof may improve plaque stability without impacting host defense.

Recruitment of tumor-associated macrophages via the CCL4-CCR5 axis promotes immune escape through PD-1 signaling in lung adenocarcinoma.

CC chemokine receptor 2 (CCR2), a class A G protein-coupled receptor (GPCR), represents a promising therapeutic target for inflammatory and autoimmune diseases. Although several CCR2 antagonists have advanced to clinical trials, none have reached the market, largely due to limited efficacy. In recent decades, binding kinetics has emerged as a key consideration in early drug discovery, complementing traditional equilibrium parameters to enhance clinical efficacy. In parallel, targeting allosteric sites offers unique advantages, i.e. insurmountablility, further improving therapeutic safety and efficacy. However, the interplay between binding kinetics and allosterism has received little attention in drug discovery as a strategy to optimize insurmountablility. As such, we developed a kinetic competition association assay, employing the intracellular allosteric radioligand [3H]LUF7482, which displayed high affinity in both equilibrium and kinetic binding assays, with consistent nanomolar KD values. After validation of the kinetic assay with unlabeled LUF7482, we profiled five known intracellular CCR2 antagonists, including the covalent binder LUF7834 as a positive control, which displayed an apparent long residence time (RT) of 576min. Functional cAMP assays further revealed a strong correlation between binding kinetics and the extent of insurmountable antagonism. Together, this study established the competition association assay as a robust approach to characterize the kinetic profiles of intracellular CCR2 antagonists, and revealed a clear correlation between binding kinetics and insurmountability. These findings may guide the selection and optimization of next-generation allosteric antagonists targeting CCR2, or the other GPCRs, in drug discovery pipelines, with the aim of improving insurmountability and, consequently, clinical efficacy.

Macrophages are key regulators of cutaneous immunity, but the traditional M1/M2 polarization model cannot fully explain their functional diversity across skin diseases. In this narrative review, we use selected skin diseases to discuss a receptor-centered view of macrophage function and to illustrate a modular "receptor-pathway-effector" framework. This perspective places macrophage receptors at the upstream sensing level, where microbial products, tissue damage signals, cytokines, immune complexes, stromal cues, and tumor-derived signals are translated into inflammatory, reparative, fibrotic, or immunosuppressive programs. We summarize representative receptor modules, including pattern-recognition receptors, cytokine and chemokine receptors, Fc and complement receptors, scavenger and efferocytosis receptors, and inhibitory checkpoint receptors. Across psoriasis, atopic dermatitis, autoimmune blistering diseases, lupus, systemic sclerosis, sarcoidosis, leprosy, melanoma, cutaneous T-cell lymphoma, diabetic wounds, and radiation-induced skin injury, these modules help explain macrophage involvement in inflammation, remodeling, host defense, impaired repair, and tumor immune escape. We also discuss selected biomarker and therapeutic examples, while distinguishing clinically explored approaches from preclinical or emerging concepts. This receptor-centered perspective may complement existing views of macrophage heterogeneity and provide a clearer way to link receptor signals with disease-related macrophage functions.

CXCR4-targeted lipid nanozymes for metastasis blockade and immune microenvironment reprogramming in hematological malignancies.

Detection of lumpy skin disease virus belonging to cluster 2.5 in flies collected during the outbreak in the Republic of Korea.

Excessive intake of saturated fats triggers inflammation in the hypothalamus, a key regulator of energy balance. In the chronic phase of this inflammatory response, bone marrow-derived and lymphoid cells are chemoattracted to this region, partially mitigating high-fat diet (HFD)-induced metabolic impairments. In rodents, the onset and magnitude of this inflammation differ between males and females, reflecting sex-specific patterns of metabolic regulation. However, how the hypothalamic chemokine profile evolves during HFD-induced inflammation, and whether it is influenced by biological sex, remains unclear. Here, male and female C57BL/6J mice were fed a HFD for 1, 3, 14, or 28 days. To isolate the role of ovarian hormones in modulating hypothalamic chemokine profile, we also analyzed ovariectomized (OVX) females with or without estrogen replacement. Quantitative polymerase chain reaction-based expression analysis revealed that most chemokines and their receptors were transiently modulated in the hypothalamus during the course of the HFD exposure, showing reduced levels in the acute phase and normalization during the chronic phase. Despite the modest sex-dependent effects observed, messenger RNA expression of the chemokine receptor C-X-C motif chemokine receptor 3 (CXCR3) was significantly higher in females than in males after 14 and 28 days of HFD, suggesting faster recruitment of CXCR3+ immune cells that may contribute to female protection against metabolic dysfunction. Females lacking ovarian hormone production displayed increased hypothalamic expression of Cxcr3 and Ccl2. Only Cxcr3 expression was partially normalized by estradiol treatment, suggesting that non-estrogenic ovarian factors may play a role in modulating specific chemokine signaling pathways. Together, our findings show that hypothalamic chemokine signaling is dynamically and transiently regulated throughout the phases of HFD-induced inflammation, with Cxcr3 modulation by HFD and ovarian hormones contributing to sex-specific resilience against metabolic inflammation.

To investigate the effects of Shenling Baizhu Powder (SLBZP) on non-tuberculous mycobacteria (NTM)-induced lung disease in mice. An NTM lung disease mouse model was established by Mycobacterium kansasii infection. C57BL/6J female mice were randomly divided into 5 groups by a random number table (n=6): negative control, NTM, SLBZP-L (2.34 g/kg), SLBZP-H (4.68 g/kg), and rifampicin (20 mg/kg). M. kansasii load in the lungs, liver, and spleen was quantified. Lung histology was performed using hematoxylin and eosin staining. Gene and cytokine expressions related to CD4+ T and natural killer (NK) cells were detected by enzyme linked immunosorbent assay, flow cytometry, real-time quantitative reverse transcription PCR, and Western blot, respectively. SLBZP-L and SLBZP-H treatments inhibited M. kansasii growth and reduced the histological damage and granuloma lesion areas in lungs of mice (P<0.01). SLBZP-H increased interleukin (IL)-17A and interferon-gamma (IFN-γ) levels, along with the proportion of CD4+ T cells, NK cells, and IFN-γ+ NK cells, while decreased IL-10 (P<0.01). Furthermore, SLBZP-H inhibited mRNA levels of tumor necrosis factor, IL-6, IL-1β, C-C motif chemokine ligand 2, C-X-C motif chemokine ligand (CXCL) 2, GATA binding protein 3 and T-bet, and increased mRNA level of retinoic acid receptor-related orphan receptor γ (P<0.05 or P<0.01). SLBZP-L and SLBZP-H also reduced the protein expressions of CXCL13 and C-X-C chemokine receptor type 5 (P<0.05 or P<0.01). SLBZP alleviated NTM-induced lung damage and enhanced NK cell immune response, which might be linked to CD4+ T cell immunity.

Activating the SDF-1/CXCR4 axis: Notoginsenoside R1-Functionalized zinc scaffolds accelerate fracture healing and angiogenesis in diabetic osteoporosis.

Immune checkpoint inhibitors (ICIs) have transformed cancer therapy by enhancing antitumor immunity but are associated with immune-related adverse events, including myocarditis. Although T cell involvement in ICI-associated myocarditis is well established, the contribution of myeloid-specific programmed death-ligand 1 (PD-L1) signaling to cardiac immune regulation remains unclear. To investigate the role of myeloid-specific PD-L1 in maintaining cardiac immune homeostasis, we generated a myeloid-specific PD-L1 conditional knockout (KO) mouse model using LysMCre-driven deletion. Cardiac function was assessed by echocardiography. Immune profiling of cardiac and systemic compartments was performed using flow cytometry, quantitative PCR, ELISA, and histological analyses. In vitro coculture assays were conducted to assess macrophage-fibroblast (FB) and macrophage-T cell interactions. Myeloid PD-L1 KO mice exhibited early-onset cardiac dysfunction, reduced left ventricular ejection fraction, left ventricular fractional shortening, and upregulated heart failure markers. Immune profiling revealed systemic and myocardial inflammation, with increased C-C chemokine receptor type 2 macrophages and activated T cells. Coculture assays confirmed that PD-L1-deficient myeloid cells enhance T cell activation, Th17 polarization, and FB-mediated fibrotic gene expression. Myeloid-specific PD-L1 plays a critical role in limiting inflammation and maintaining cardiac integrity. Its deficiency promotes a proinflammatory microenvironment, contributing to cardiac dysfunction and implicating it as a key player in ICI-associated myocarditis. These findings identify myeloid PD-L1 as a potential therapeutic target to mitigate immune-mediated cardiotoxicity.NEW & NOTEWORTHY Immune checkpoint inhibitor-associated myocarditis is incompletely understood beyond T cell-driven mechanisms. This study identifies myeloid-specific PD-L1 as a critical regulator of cardiac immune homeostasis. Loss of myeloid PD-L1 triggers early myocardial inflammation, immune cell infiltration, FB activation, and subsequent cardiac dysfunction. These findings uncover a previously unrecognized myeloid checkpoint pathway contributing to immune-mediated cardiotoxicity and highlight myeloid PD-L1 as a potential therapeutic target.

The role of ferroptosis in epilepsy: mechanisms and targeted therapies.

Glioblastoma is the most lethal primary brain tumor, characterized by a profoundly immunosuppressive microenvironment. This stroma includes various immunosuppressive and tumor-killing cells. This review critically evaluates emerging strategies for reprogramming the glioblastoma microenvironment to restore antitumor immunity. We focus on novel small molecules, natural products, adjuvants, and nanomedicine platforms that can remodel immunosuppressive microenvironment of glioblastoma. Preclinical studies demonstrate that therapy modalities can induce various forms of cell death and the release of danger signals that not only stimulate immunogenic responses but also cause the regulation of checkpoint molecules. In addition, several cytokines and danger signals can stimulate signal transducer and activator of transcription 3 (STAT3) and nuclear factor of κappa B (NF‑κB) in cancer and immune cells. These factors not only enhance resistance to apoptosis but also boost immunosuppressive responses. Targeting cancer-associated fibroblasts (CAFs) and their specific secretions, reprogramming marcrophages using colony-stimulating factor-1 (CSF-1) inhibitors or toll-like receptor (TLR) agonists, depleting myeloid cells through chemokine receptor blockade, and disrupting metabolic suppression can each partially remodel glioblastoma microenvironment. Nanocomplexes improve brain delivery and enable multimodal drug co-delivery. However, clinical translation has been disappointing for checkpoint inhibitors in phase III trials. Furthermore, myeloid-targeted agents have shown limited efficacy because of the profound plasticity and redundancy of the glioblastoma microenvironment. Effective immunotherapy for glioblastoma will require rationally designed multimodal combinations that simultaneously target the stromal barriers, the immunosuppressive milieu, and the exhausted state of T cells. Emerging strategies such as oncolytic viruses engineered to express immunomodulatory payloads and biomarker-guided adaptive trial designs can be promising for future studies.

Expression patterns of CXCR4, ITGB1, and FGFR3 in feline spermatogonial stem cells.

Molecular theranostics has revolutionized the field of personalized medicine, specifically augmenting "precision oncology" and is now integral in the management of malignancies like differentiated thyroid carcinoma, neuroendocrine tumors, and metastatic carcinoma prostate. The potential of theranostics is huge with possible applications in a variety of tumors, including at their early stages. This article will focus on the advancements in nuclear theranostics-highlighting the expanded indications of already established radionuclide therapies like peptide receptor radionuclide therapy (PRRT), prostate specific membrane antigen radioligand therapy (PRLT), and meta-iodobenzylguanidine therapy (MIBG therapy); and also on novel radiolabeled theranostic agents targeting fibroblast activated protein (FAPI-based radiopharmaceuticals), chemokine receptor targeting agents (pentixfor/pentixather), integrins, cholecystokinin receptors and their potential applications.

Chemotactic receptors involved in generation of ectopic pulmonary germinal centers (GCs) within inducible bronchus-associated lymphoid tissue (iBALT) are poorly defined. Here, using CIBER Cxcr3-reporter mice, we demonstrate that the prototypical type 1 inflammatory chemokine receptor CXCR3 is highly induced in influenza A virus (IAV)-reactive B cells in the mediastinal lymph node, spleen, lung, peripheral blood, and airways following intranasal infection. Notably, elevated Cxcr3 was observed in ectopic pulmonary germinal center B (GCB) cells in iBALT relative to their contemporaneous counterparts in secondary lymphoid organs across the timecourse of the response to IAV infection. Mice with a B cell-specific deletion of Cxcr3 displayed a 50 to 60% reduction in the frequency and number of ectopic GCB cells in the lungs at the peak of the response following IAV infection, relative to controls. Furthermore, in cotransfers, Cxcr3-deficient B cells were substantially outcompeted by their Cxcr3-sufficient counterparts for ectopic pulmonary GC participation, but were not impacted with respect to GCB cell frequencies in other compartments. Thus, the data elucidate the requirement of B cell-intrinsic CXCR3 expression for efficient generation of ectopic pulmonary GCB cell responses in iBALT following respiratory viral infection with IAV, a finding that broadens understanding of the molecular cues underpinning this key component of local protective humoral immunity to IAV.

Chemokines are proteins involved in various cellular processes; however, their participation in the pathogenesis of lesions containing multinucleated giant cells (MGC) has not been fully elucidated. This study investigated the immunoexpression of chemokine CXCL12 and its receptor CXCR4 in giant cell granulomas of the jaws (central giant cell granuloma [CGCG] and peripheral giant cell granuloma [PGCG]) and giant cell tumor of bone (GCTB). Forty-five giant cell granulomas of the jaws (15 non-aggressive CGCG, 15 aggressive CGCG, and 15 PGCG) and 15 GCTB were selected. The percentages of cytoplasmic (CXCL12 and CXCR4) and nuclear (CXCR4) positivity in mononuclear cells (MC) and in non-cannibalistic (ncMGC) and cannibalistic MGC (cMGC) were determined. All groups exhibited low median percentages of positivity for CXCL12 in MC (p>0.05). In ncMGC and cMGC, the highest median percentages of CXCL12 positivity were observed in GCTB (p>0.05). Cytoplasmic immunoexpression of CXCR4 was observed in all groups evaluated, with high median percentages of positivity in ncMGC and cMGC. Compared to non-aggressive CGCG, GCTB exhibited significantly higher cytoplasmic expression of CXCR4 in ncMGC (p<0.05). In MC, the highest median percentage of CXCR4 positivity was observed in GCTB, with a statistically significant difference compared to PGCG (p<0.05). All groups showed low median percentages of nuclear expression of CXCR4. Compared to PGCG, GCTB exhibited higher nuclear expression of CXCR4 in MC (p<0.05). Strong positive correlations were found between cytoplasmic and nuclear expression of CXCR4 in MC of non-aggressive CGCG, PGCG, and GCTB (p<0.05). The results suggest the potential involvement of CXCR4 in the pathogenesis of giant cell granulomas of the jaws and GCTB. This chemokine receptor may also contribute to differences in the biological behavior of these MGC-containing lesions. The relevance of CXCL12 for the development of the giant cell lesions studied appears to be variable.

Intestinal fibrosis presents a major clinical challenge in Crohn's disease (CD) due to the lack of effective pharmacological interventions. The underlying mechanisms of intestinal fibrosis remain largely elusive. Reanalysis of the single-cell RNA-seq data from full-thickness CD tissue identifies a distinct profibrotic macrophage subset characterized by high S100A8 and S100A9 expression. CellChat analysis indicates strong communication between this S100A8/A9-high (S100A8/A9hi) macrophage subset and fibroblasts. Adoptive transfer of S100A8/A9hi macrophages exacerbate intestinal fibrosis in mice with chronic dextran sulfate sodium (DSS)-induced colitis. Consequently, pharmacological inhibition of S100A8/A9 significantly ameliorates intestinal fibrosis in murine chronic colitis. Proteomic analysis further identifies murine CCL6 (mCCL6) as the key pro-fibrotic mediator secreted by S100A8/A9hi macrophages, which acts via CC chemokine receptor 1 (CCR1) to regulate fibroblasts. Antibody blockade of mCCL6 alleviates established intestinal fibrosis in a DSS-induced colitis model. Mechanistically, S100A8/A9hi macrophages drive mCCL6 production via STAT3 activation. Similarly, the human ortholog of CCL6, CCL15 (hCCL15), exerts pro-fibrotic effects on fibroblasts via the CCR1 receptor. Our findings reveal that targeting S100A8/A9hi macrophage may be a therapeutic strategy against intestinal fibrosis in CD.

Targeting the neutrophil-DPP-1-protease axis in airway disease: current evidence and future indications.

Diagnostic Value of CCL2 and CCR2 in Pleural Effusion for Distinguishing Lung Cancer Histological Subtypes: A Retrospective Study.

In chronic lymphocytic leukemia (CLL), B-cell receptor, chemokine receptor and integrin signaling contribute to disease progression by influencing cell survival, migration and microenvironment interactions. Focal adhesion kinase (FAK) has recently been involved in these disease processes. Our recent research revealed a correlation between activated FAK and molecules involved in CLL aggressiveness, particularly in IGHV-unmutated cases, including the Lyn kinase substrates HS1 and cortactin. In this context, ROR1 is a key player, sharing connections with Lyn substrates and FAK pathways. We assessed FAK and ROR1 bidirectional association by stimulating CLL cells with Wnt5a and measuring FAK phosphorylation by Western blot, while ROR1 expression was evaluated following FAK inhibitor treatment. Flow cytometry using CXCR4 and CD5 markers was performed to identify and sort proliferating (CXCR4dim/CD5bright) versus quiescent (CXCR4bright/CD5dim) B-cell subpopulations from CLL patients. FAK and ROR1 levels were compared between these fractions. Findings were further supported ex vivo in ibrutinib-treated patients. The FAK inhibitor defactinib was tested alone and in combination with BTK inhibitors on primary CLL cells cultured with or without stromal support, measuring apoptosis by Annexin V/PI staining. We demonstrated that ROR1 triggering by Wnt5a increases FAK activation, while FAK inhibition reduces ROR1 expression. Significantly higher levels of FAK and ROR1 were detected in the proliferating subpopulation corresponding to cells egressing lymph nodes compared to quiescent cells. Ex vivo experiments confirmed high FAK and ROR1 levels in circulating lymphocytes redistributing from secondary lymphoid organs. Defactinib significantly enhanced apoptosis in CLL cells when combined with BTK inhibitors, even in supportive microenvironments, showing significant efficacy also against aggressive CLLs. Our findings reveal a reciprocal regulatory relationship between FAK and ROR1, with both proteins enriched in CLL cells that have exited the lymph nodes. Given defactinib's favorable safety profile in solid tumor trials, combining FAK inhibition with BTK inhibitors could enhance therapeutic efficacy by limiting leukemic clone adaptability and addressing resistance and relapse. While anti-ROR1 therapies showed limited efficacy as monotherapy in CLL trials, targeting multiple nodes of this regulatory network may prove more effective.