Targeting CCR3 with antagonist SB 328437 sensitizes 5­fluorouracil­resistant gastric cancer cells: Experimental evidence and computational insights.

Gastric cancer (GC) ranks fifth globally in cancer diagnoses and third for cancer-related deaths. Chemotherapy with 5-fluorouracil (5-FU), a primary treatment, faces challenges due to the development of chemoresistance. Tumor microenvironment factors, including C-C motif chemokine receptor 3 (CCR3), can contribute to chemoresistance. The present study evaluated the effect of CCR3 receptor inhibition using the antagonist SB 328437 and the molecular dynamics of this interaction on resistance to 5-FU in gastric cancer cells. The 5-FU-resistant AGS cell line (AGS R-5FU) demonstrated notable tolerance to higher concentrations of 5-FU, with a 2.6-fold increase compared with the parental AGS cell line. Furthermore, the mRNA expression levels of thymidylate synthase (TS), a molecular marker for 5-FU resistance, were significantly elevated in AGS R-5FU cells. CCR3 was shown to be expressed at significantly higher levels in these resistant cells. Combining SB 328437 with 5-FU resulted in a significant decrease in cell viability, particularly at higher concentrations of 5-FU. Furthermore, when SB 328437 was combined with 5-FU at a high concentration, the relative mRNA expression levels of CCR3 and TS decreased significantly. Computational analysis of CCR3 demonstrated dynamic conformational changes, especially in extracellular loop 2 region, which indicated potential alterations in ligand recognition. Docking simulations demonstrated that SB 328437 bound to the allosteric site of CCR3, inducing a conformational change in ECL2 and hindering ligand recognition. The present study provides comprehensive information on the molecular and structural aspects of 5-FU resistance and CCR3 modulation, highlighting the potential for therapeutic application of SB 328437 in GC treatment.

Novel CCR3-targeted cyclic peptides as potential therapeutic agents for age-related macular degeneration via inhibiting angiogenesis and reducing retinal photoreceptor damage.

The prolonged intravitreal administration of anti-vascular endothelial growth factor (VEGF) drugs is prone to inducing aberrant retinal vascular development and causing damage to retinal neurons. Hence, we have taken an alternative approach by designing and synthesizing a series of cyclic peptides targeting CC motif chemokine receptor 3 (CCR3). Based on the binding mode of the N-terminal region in CCR3 protein to CCL11, we used computer-aided identification of key amino acid sequence, conformational restriction through different cyclization methods, designed and synthesized a series of target cyclic peptides, and screened the preferred compound IB-2 through affinity. IB-2 exhibits excellent anti-angiogenic activity in HRECs. The apoptosis level of 661W cells demonstrated a significant decrease with the escalating concentration of IB-2. This suggests that IB-2 may have a protective effect on photoreceptor cells. In vivo experiments have shown that IB-2 significantly reduces retinal vascular leakage and choroidal neovascularization (CNV) area in a laser-induced mouse model of CNV. These findings indicate the potential of IB-2 as a safe and effective therapeutic agent for AMD, warranting further development.

AMG487 alleviates influenza A (H1N1) virus-induced pulmonary inflammation through decreasing IFN-γ-producing lymphocytes and IFN-γ concentrations.

BACKGROUND AND PURPOSE: Severe influenza virus-infected patients have high systemic levels of Th1 cytokines (including IFN-γ). Intrapulmonary IFN-γ increases pulmonary IFN-γ-producing T lymphocytes through the CXCR3 pathway. Virus-infected mice lacking IP-10/CXCR3 demonstrate lower pulmonary neutrophilic inflammation. AMG487, an IP-10/CXCR3 antagonist, ameliorates virus-induced lung injury in vivo through decreasing viral loads. This study examined whether AMG487 could treat H1N1 virus-induced mouse illness through reducing viral loads or decreasing the number of lymphocytes or neutrophils. EXPERIMENTAL APPROACH: Here, we studied the above-mentioned effects and underlying mechanisms in vivo. KEY RESULTS: H1N1 virus infection caused bad overall condition and pulmonary inflammation characterized by the infiltration of lymphocytes and neutrophils. From Day-5 to Day-10 post-virus infection, bad overall condition, pulmonary lymphocytes, and IFN-γ concentrations increased, while pulmonary H1N1 viral titres and neutrophils decreased. Both anti-IFN-γ and AMG487 alleviated virus infection-induced bad overall condition and pulmonary lymphocytic inflammation. Pulmonary neutrophilic inflammation was mitigated by AMG487 on Day-5 post-infection, but was not mitigated by AMG487 on Day-10 post-infection. H1N1 virus induced increases of IFN-γ, IP-10, and IFN-γ-producing lymphocytes and activation of the Jak2-Stat1 pathways in mouse lungs, which were inhibited by AMG487. Anti-IFN-γ decreased IFN-γ and IFN-γ-producing lymphocytes on Day-5 post-infection. AMG487 but not anti-IFN-γ decreased viral titres in mouse lung homogenates or BALF. Higher virus load did not increase pulmonary inflammation and IFN-γ concentrations when mice were treated with AMG487. CONCLUSION AND IMPLICATIONS: AMG487 may ameliorate H1N1 virus-induced pulmonary inflammation through decreasing IFN-γ-producing lymphocytes rather than reducing viral loads or neutrophils.

ACKR3 Proximity Labeling Identifies Novel G protein- and ß-arrestin-independent GPCR Interacting Proteins.

The canonical paradigm of GPCR signaling recognizes G proteins and ß-arrestins as the two primary transducers that promote GPCR signaling. Recent evidence suggests the atypical chemokine receptor 3 (ACKR3) does not couple to G proteins, and ß-arrestins are dispensable for some of its functions. Here, we employed proximity labeling to identify proteins that interact with ACKR3 in cells devoid of ß-arrestin. We identified proteins involved in the endocytic machinery and evaluated a subset of proteins conserved across several GPCR-based proximity labeling experiments. We discovered that the bone morphogenic protein 2-inducible kinase (BMP2K) interacts with many different GPCRs with varying dependency on ß-arrestin. Together, our work highlights the existence of modulators that can act independently of G proteins and ß-arrestins to regulate GPCR signaling and provides important evidence for other targets that may regulate GPCR signaling.

IgE directly affects eosinophil migration in chronic rhinosinusitis with nasal polyps through CCR3 and predicts the efficacy of omalizumab.

BACKGROUND: Whether IgE affects eosinophil migration in chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unclear. Moreover, our understanding of local IgE, eosinophils, and omalizumab efficacy in CRSwNP remains limited. OBJECTIVE: We investigated whether IgE acts directly on eosinophils and determined its role in omalizumab therapy. METHODS: Eosinophils and their surface receptors were detected by hematoxylin and eosin staining and flow cytometry. IgE and its receptors, eosinophil peroxidase (EPX), eosinophilic cationic protein, and CCR3 were detected by immunohistochemistry and immunofluorescence. Functional analyses were performed on blood eosinophils and polyp tissues. Logistic regression was performed to screen for risk factors. Receiver operating characteristic curve was generated to evaluate the accuracy. RESULTS: Both FcεRI and CD23 were expressed on eosinophils. The expression of FcεRI and CD23 on eosinophil in nasal polyp tissue was higher than in peripheral blood (both P < .001). IgE and EPX colocalized in CRSwNP. IgE directly promoted eosinophil migration by upregulating CCR3 in CRSwNP but not in healthy controls. Omalizumab and lumiliximab were found to be effective in restraining this migration, indicating CD23 was involved in IgE-induced eosinophil migration. Both IgE+ and EPX+ cells were significantly reduced after omalizumab treatment in those who experienced response (IgE+ cells, P = .001; EPX+ cells, P = .016) but not in those with no response (IgE+ cells, P = .060; EPX+ cells, P = .151). Baseline IgE+ cell levels were higher in those with response compared to those without response (P = .024). The baseline local IgE+ cell count predicted omalizumab efficacy with an accuracy of 0.811. CONCLUSIONS: IgE directly promotes eosinophil migration, and baseline local IgE+ cell counts are predictive of omalizumab efficacy in CRSwNP.

Pharmacokinetics, pharmacodynamics and safety of the novel C-X-C chemokine receptor 3 antagonist ACT-777991: Results from the first-in-human study in healthy adults.

AIMS: The C-X-C chemokine receptor 3 (CXCR3) axis is highly upregulated in the tissue of patients with type 1 diabetes. Antagonizing CXCR3 may reduce the migration of CXCR3-expressing cells to the pancreas. The pharmacokinetics (PKs), target engagement (TE) (inhibition of CXCR3 internalization) and safety of single- and multiple-ascending doses (SADs and MADs) of ACT-777991, a novel orally available potent CXCR3 antagonist, were assessed in a double-blind, randomized, placebo-controlled phase 1 study. METHODS: Doses up to 100 mg (SAD part) and 40 mg twice daily (MAD part) were investigated in a total of 70 male and female healthy participants. Food effect was integrated as an SAD subpart. PK, TE, safety and tolerability data were collected up to 4 days after (last) dosing. RESULTS: In both SAD and MAD parts, ACT-777991 was rapidly absorbed with a time to reach maximum concentration between 0.5 and 1.5 h post dose, followed by a biphasic disposition with a terminal half-life between 9.7 and 10.3 h. Increase in exposure and maximum concentration of ACT-777991 were dose-proportional. Steady state was reached after 48 h with minimal accumulation. The rate but not the extent of absorption was modified by food intake. A dose-dependent TE was demonstrated in both SAD and MAD parts. ACT-777991 was well tolerated. Neither a treatment-related pattern nor a dose-response relationship was determined for adverse events or any safety variable. No QT prolongation liability of regulatory concern was detected. CONCLUSIONS: In this first-in-human study, ACT-777991 showed good tolerability for all doses tested and a PK and TE profile suitable for further clinical development.

Profiling CCR3 target pathways for discovering novel antagonists from natural products using label-free cell phenotypic assays.

CC chemokine receptor 3 (CCR3) plays important roles in atopic dermatitis (AD) and other related allergic diseases. Activation of CCR3 receptor signaling pathways regulates the recruitment of eosinophils to related tissues, releasing inflammatory mediators and causing inflammatory responses. However, none of the known CCR3 antagonists exhibit promising efficacy in clinical trials. In this work, we sought new natural CCR3 antagonists for drug development. To construct a high-throughput screening model, we established a stably transfected CHO-K1-Gα15-CCR3 cell line, and receptor expression was demonstrated by real-time quantitative PCR, confocal detection and flow cytometry analysis. Then, we applied a label-free cell phenotyping technique to profile and deconvolute CCR3 target pathways in CHO-K1-Gα15-CCR3 cells and found that activation of CCR3 triggered the Gq-PLC-Ca2+ and MAPK-P38-ERK pathways. By in vitro and in silico experiments, we discovered a novel CCR3 antagonist emodin, with an IC50 value of 27.28 ± 1.71 µM out of 266 compounds that were identified in 15 traditional Chinese medicines used in the clinical treatment of skin diseases. Molecular docking graphically presented the binding mode of emodin on CCR3. This work reports a new approach for CCR3 antagonist screening and pathway detection and identifies a new antagonist that would benefit future drug development.

Studying allosteric regulation of chemokines and antagonists using a nanoscale hCCR3 receptor sensor.

CC chemokine receptor-3 (hCCR3), a G protein-coupled receptor (GPCR) expressed predominantly on eosinophils, is an important drug target. However, it was unclear how chemokine ligands, activators and antagonists recognize hCCR3, and quantitative measurements of hCCR3 inhibition or activation were rare. This study constructed a nanogold receptor sensor using hCCR3 as the molecular recognition element and horseradish peroxidase as the signal amplifier. We quantified the kinetic antagonism between chemokines and hCCR3 before and after adding hCCR3 antagonists. A molecular docking study was carried out to investigate how hCCR3 and its ligands work. The study results indicate chemokines interact with hCCR3 at low concentrations, and reversible hCCR3 inhibitors solely inhibit hCCR3, not CCLs. Moreover, a quantitative evaluation of hCCR3 chemokine activators and their antagonists was carried out using a directed weighted network. This offers a novel approach to quantitatively evaluate chemokine-receptor activation and antagonism together. This research could potentially offer new insights into the mechanisms of action of chemokines and drug screening.

Intrapulmonary IFN-γ instillation causes chronic lymphocytic inflammation in the spleen and lung through the CXCR3 pathway.

Some patients with chronic refractory cough have high levels of pulmonary IFN-γ and IFN-γ-producing T lymphocytes. Pulmonary IFN-γ administration causes acute airway lymphocytic inflammation and cough hypersensitivity by increasing the number of pulmonary IFN-γ-producing T lymphocytes, but these lymphocytes may be recruited from other organs. Intraperitoneal IFN-γ injection can increase the spleen weight of mice. It remains elusive whether pulmonary IFN-γ can induce chronic airway lymphocytic inflammation and cough hypersensitivity by stimulating the proliferation of IFN-γ -producing T lymphocytes in the spleen. Here, we found that pulmonary IFN-γ administration induced chronic airway inflammation and chronic cough hypersensitivity with an increased number of IFN-γ-producing T lymphocytes in the spleen, blood and lung. Pulmonary IFN-γ administration also increased 1) the proliferation of spleen lymphocytes in vivo and 2) the IP-10 level and CXCR3+ T lymphocyte numbers in the spleen and lung of mice. IP-10 could promote the proliferation of spleen lymphocytes in vitro but not blood lymphocytes or lung-resident lymphocytes. AMG487, a potent inhibitor of binding between IP-10 and CXCR3, could block pulmonary IFN-γ instillation-induced chronic airway lymphocytic inflammation and the proliferation of IFN-γ-producing T lymphocytes in mouse spleens. In conclusion, intrapulmonary IFN-γ instillation may induce the proliferation of splenic IFN-γ-producing T lymphocytes through IP-10 and the CXCR3 pathway. The IFN-γ-producing T lymphocytes in blood, partly released from the mouse spleen, may be partly attracted to the lung by pulmonary IP-10 through the CXCR3 pathway. IFN-γ-producing T lymphocytes and IFN-γ in the lung may cause chronic airway lymphocytic inflammation and chronic cough hypersensitivity.

G protein activation via chemokine (C-X-C motif) receptor 4 and α1b -adrenoceptor is ligand and heteromer-dependent.

It is unknown whether heteromerization between chemokine (C-X-C motif) receptor 4 (CXCR4), atypical chemokine receptor 3 (ACKR3) and α1b -adrenoceptor (α1b -AR) influences effects of the CXCR4/ACKR3 agonist chemokine (C-X-C motif) ligand 12 (CXCL12) and the noncognate CXCR4 agonist ubiquitin on agonist-promoted G protein activation. We provide biophysical evidence that both ligands stimulate CXCR4-mediated Gαi activation. Unlike CXCL12, ubiquitin fails to recruit ß-arrestin. Both ligands differentially modulate the conformation of CXCR4:ACKR3 heterodimers and its propensity to hetero-trimerize with α1b -AR. CXCR4:ACKR3 heterodimerization reduces the potency of CXCL12, but not of ubiquitin, to activate Gαi. Ubiquitin enhances phenylephrine-stimulated α1b -AR-promoted Gαq activation from hetero-oligomers comprising CXCR4. CXCL12 enhances phenylephrine-stimulated α1b -AR-promoted Gαq activation from CXCR4:α1b -AR heterodimers and reduces phenylephrine-stimulated α1b -AR-promoted Gαq activation from ACKR3 comprising heterodimers and trimers. Our findings suggest heteromer and ligand-dependent functions of the receptor partners.

Chemokine CCL7 mediates trigeminal neuropathic pain via CCR2/CCR3-ERK pathway in the trigeminal ganglion of mice.

BACKGROUND: Chemokine-mediated neuroinflammation plays an important role in the pathogenesis of neuropathic pain. The chemokine CC motif ligand 7 (CCL7) and its receptor CCR2 have been reported to contribute to neuropathic pain via astrocyte-microglial interaction in the spinal cord. Whether CCL7 in the trigeminal ganglion (TG) involves in trigeminal neuropathic pain and the involved mechanism remain largely unknown. METHODS: The partial infraorbital nerve transection (pIONT) was used to induce trigeminal neuropathic pain in mice. The expression of Ccl7, Ccr1, Ccr2, and Ccr3 was examined by real-time quantitative polymerase chain reaction. The distribution of CCL7, CCR2, and CCR3 was detected by immunofluorescence double-staining. The activation of extracellular signal-regulated kinase (ERK) was examined by Western blot and immunofluorescence. The effect of CCL7 on neuronal excitability was tested by whole-cell patch clamp recording. The effect of selective antagonists for CCR1, CCR2, and CCR3 on pain hypersensitivity was checked by behavioral testing. RESULTS: Ccl7 was persistently increased in neurons of TG after pIONT, and specific inhibition of CCL7 in the TG effectively relieved pIONT-induced orofacial mechanical allodynia. Intra-TG injection of recombinant CCL7 induced mechanical allodynia and increased the phosphorylation of ERK in the TG. Incubation of CCL7 with TG neurons also dose-dependently enhanced the neuronal excitability. Furthermore, pIONT increased the expression of CCL7 receptors Ccr1, Ccr2, and Ccr3. The intra-TG injection of the specific antagonist of CCR2 or CCR3 but not of CCR1 alleviated pIONT-induced orofacial mechanical allodynia and reduced ERK activation. Immunostaining showed that CCR2 and CCR3 are expressed in TG neurons, and CCL7-induced hyperexcitability of TG neurons was decreased by antagonists of CCR2 or CCR3. CONCLUSION: CCL7 activates ERK in TG neurons via CCR2 and CCR3 to enhance neuronal excitability, which contributes to the maintenance of trigeminal neuropathic pain. CCL7-CCR2/CCR3-ERK pathway may be potential targets for treating trigeminal neuropathic pain.

Epidemiological analysis on the susceptibility of CXCR3 gene polymorphism to COPD in the elderly population in Liangjiang New Area of Chongqing / 公共卫生与预防医学

Objective To explore and analyze the epidemiology of susceptibility to chronic obstructive pulmonary disease (COPD) among the elderly population in Liangjiang New Area of Chongqing based on CXC chemokine receptor 3 (CXCR3) gene polymorphism. Methods From January 2020 to September 2022, the Medical Laboratory Department of Chongqing Liangjiang New Area People's Hospital selected COPD patients and received treatment. Among the 276 patients who met the criteria were included in the study and included in the observation group. Among the 512 patients with healthy pulmonary function in the same period were included in the control group. The data of the two groups of patients were analyzed, and the genotypes were detected by SBaPhotoshot technology to analyze the relationship between gene polymorphism and the susceptibility and clinical characteristics of COPD. Results There was no significant difference between the two groups in age, sex, BMI and blood eosinophil granulocyte levels, which was comparable (P>0.05). There were significant differences in smoking history, pulmonary function index , MMP-9 and TIMP-1 levels (P0.05). In the observation group, the MMP-9 level of rs2280964 locus was significantly different (P=0.003), while the TIMP-1 level was not significantly different (P=0.187); There was no significant difference in MMP-9 and TIMP-1 levels among the three genes at rs34334103 locus (all P>0.05). The level of MMP-9 in homozygous TT patients with rs2280964 locus was significantly higher than that in homozygous CC patients (P=0.024). There were differences in FEV1/FVC of patients with CXCR3 rs34,334,103 gene distribution (P=0.008), among which there were significant differences in CC+CT and TT recessive models (P0.05). Conclusion CXCR3 gene polymorphism is significantly associated with the susceptibility to COPD, and also with the serum levels of MMP-9 and FEV1/FVC, which can be used as a new target for clinical research and treatment.

Pulmonary IFN-γ Causes Lymphocytic Inflammation and Cough Hypersensitivity by Increasing the Number of IFN-γ-Secreting T Lymphocytes.

PURPOSE: Respiratory viral infection increases the number of lung-resident T lymphocytes, which enhance cough sensitivity by producing interferon-γ (IFN-γ). It is poorly understood why IFN-γ-secreting T lymphocytes persist for a long time when the respiratory viruses have been removed. METHODS: Repeated pulmonary administration of IFN-γ and intraperitoneal injection with different inhibitors were used to study the effects of pulmonary IFN-γ in mice and guinea pigs. RESULTS: IFN-γ administration caused the increasing of IFN-γ-secreting T lymphocytes in both lung and blood, followed by the elevated physiological level of IFN-γ in the lung, the airway inflammation and the airway epithelial damage. IFN-γ administration also enhanced the cough sensitivity of guinea pigs. IFN-γ activated the STAT1 and extracellular signal-regulated kinase (ERK) pathways in lung tissues, released IFN-γ-inducible protein 10 (IP-10), and resulted in F-actin accumulation in lung-resident lymphocytes. The CXC chemokine receptor 3 (CXCR3) inhibitor potently suppressed all the IFN-γ-induced inflammatory changes. The STAT1 inhibitor mitigated IFN-γ-secreting T lymphocytes infiltration by inhibiting T lymphocytes proliferation. F-actin accumulation and the ERK1/2 pathway contributed to pulmonary IFN-γ-induced augmentation of the airway inflammation and increasing of IFN-γ-secreting T lymphocytes in blood. CONCLUSIONS: High physiological levels of IFN-γ in the lung may cause pulmonary lymphocytic inflammation and cough hypersensitivity by increasing the number of IFN-γ-secreting T lymphocytes through the IP-10 and CXCR3 pathways.

Selective Elimination of Senescent Fibroblasts by Targeting the Cell Surface Protein ACKR3.

The accumulation of senescent cells in aging tissues is associated with age-related diseases and functional decline. Thus, senolysis, a therapy aimed at rejuvenation by removing senescent cells from the body, is being developed. However, this therapy requires the identification of membrane surface antigens that are specifically expressed on senescent cells for their selective elimination. We showed that atypical chemokine receptor 3 (ACKR3), a receptor of the CXC motif chemokine 12 (CXCL12) implicated in cancer, inflammation, and cardiovascular disorders, is selectively expressed on the surface of senescent human fibroblasts but not on proliferating cells. Importantly, the differential presence of ACKR3 enabled the isolation of senescent cells by flow cytometry using anti-ACKR3 antibodies. Furthermore, antibody-dependent cellular cytotoxicity assays revealed that cell surface ACKR3 preferentially sensitizes senescent but not dividing fibroblasts to cell injury by natural killer cells. Conclusively, the selective expression of ACKR3 on the surface of senescent cells allows the preferential elimination of senescent cells. These results might contribute to the future development of novel senolysis approaches.

Stimulation of the atypical chemokine receptor 3 (ACKR3) by a small-molecule agonist attenuates fibrosis in a preclinical liver but not lung injury model.

Atypical chemokine receptor 3 (ACKR3, formerly CXC chemokine receptor 7) is a G protein-coupled receptor that recruits ß-arrestins, but is devoid of functional G protein signaling after receptor stimulation. In preclinical models of liver and lung fibrosis, ACKR3 was previously shown to be upregulated after acute injury in liver sinusoidal and pulmonary capillary endothelial cells, respectively. This upregulation was linked with a pro-regenerative and anti-fibrotic role for ACKR3. A recently described ACKR3-targeting small molecule agonist protected mice from isoproterenol-induced cardiac fibrosis. Here, we aimed to evaluate its protective role in preclinical models of liver and lung fibrosis. After confirming its in vitro pharmacological activity (i.e., ACKR3-mediated ß-arrestin recruitment and receptor binding), in vivo administration of this ACKR3 agonist led to increased mouse CXCL12 plasma levels, indicating in vivo interaction of the agonist with ACKR3. Whereas twice daily in vivo administration of the ACKR3 agonist lacked inhibitory effect on bleomycin-induced lung fibrosis, it had a modest, but significant anti-fibrotic effect in the carbon tetrachloride (CCl4)-induced liver fibrosis model. In the latter model, ACKR3 stimulation affected the expression of several fibrosis-related genes and led to reduced collagen content as determined by picro-sirius red staining and hydroxyproline quantification. These data confirm that ACKR3 agonism, at least to some extent, attenuates fibrosis, although this effect is rather modest and heterogeneous across various tissue types. Stimulating ACKR3 alone without intervening in other signaling pathways involved in the multicellular crosstalk leading to fibrosis will, therefore, most likely not be sufficient to deliver a satisfactory clinical outcome.

Anti­VEGF antibody triggers the effect of anti­PD­L1 antibody in PD­L1low and immune desert­like mouse tumors.

The efficacy of programmed cell death­ligand 1 (PD­L1)/programmed cell death protein 1 (PD­1) blockade therapy has been demonstrated but is limited in patients with PD­L1low or immune desert tumors. This limitation can be overcome by combination therapies that include anti­vascular endothelial growth factor (VEGF) therapy. Such combinations have been investigated in clinical trials for a number of cancer types; however, evidence on the mechanisms underlying their effects in these types of patients is still not sufficient. Therefore, the present study investigated the efficacy and effects on CD8+ T cell and C­X­C motif chemokine receptor 3 (CXCR3) ligand expression in tumors by combining anti­PD­L1 and anti­VEGF antibodies using an OV2944­HM­1 mouse model with PD­L1low and immune desert­like phenotypes. Although the model exhibited anti­PD­L1 insensitivity, anti­PD­L1 antibody treatment combined with anti­VEGF antibody inhibited tumor growth compared with anti­VEGF monotherapy, which itself inhibited tumor growth compared with the control treatment on Day 25. In combination­treated mice, a higher percentage of CD8+ T cells and higher levels of CXCR3 ligands were observed in tumor tissues compared with those in the anti­VEGF antibody treatment group, which was not significantly different from control treatment on Day 8. The increase in the intratumoral percentage of CD8+ T cells following the combination treatment was reversed by CXCR3 blocking to the same level as the control. In an anti­PD­L1 insensitive model with PD­L1low and immune desert­like phenotypes, although anti­PD­L1 antibody alone was not effective, anti­PD­L1 antibody in combination with anti­VEGF antibody exhibited antitumor combination efficacy with an increase of CD8+ T cell infiltration, which was suggested to be dependent on the increase of intratumoral CXCR3 ligands. This mechanism could explain the efficacy of anti­PD­L1 antibody and anti­VEGF antibody combination therapy in the clinical setting.

Effect of Shufeng Tongluo Prescription on Eotaxin and CCR3 Protein Expression and ERK Phosphorylation Level of Asthma Mice / 中国实验方剂学杂志

ObjectiveTo preliminarily explore the mechanism of Shufeng Tongluo prescription （SFTLP） in inhibiting airway inflammation in asthma mice by affecting the expression levels of eotaxin in the serum， CC type chemokine receptor 3 （CCR3）， and extracellular signal-regulated kinase （ERK） phosphorylation in lung tissues. MethodSeventy C57BL/6 mice were randomly divided into a blank group， a model group， low-， medium-， and high-dose SFTLP groups （7.75， 15.5， 30 g·kg-1）， a pertussis toxin （PTX） group， a CCR3 inhibitor （SB328437） group， a phosphoinositide 3-kinase （PI3K） inhibitor （LY294002） group， a p38 protein kinase antagonist inhibitor （SB203580） group， and an ERK inhibitor （PD98059） group. The asthma model was induced in mice by intraperitoneal injection of ovalbumin （OVA） and aluminum hydroxide ［Al（OH）3］ combined with OVA atomization （0.2 mL for all）. After modeling， hematoxylin-eosin staining （HE staining） was used to observe the inflammatory infiltration of lung tissues in mice. Enzyme-linked immunosorbent assay （ELISA） was used to detect the serum levels of eotaxin ［CC chemokine ligand （CCL） 11 and CCL24） in each group. Western blot was used to detect the levels of ERK phosphorylation and CCR3 in lung tissues. ResultCompared with the blank group， the model group showed obvious bronchial constriction， lumen stenosis， damaged alveolar structure， massive inflammatory cell infiltration in lung tissues， mucous plug in the bronchus， edema in the submucosal tissues of the trachea， increased folds， increased serum levels of CCL11 and CCL24 （P<0.01）， and increased expression of CCR3 protein in lung tissues （P<0.05）. The ERK levels in lung tissues of the model group and the PTX group increased （P<0.05）. The level of p-ERK in lung tissues of the model group and the low-dose SFTLP group increased （P<0.05）. As revealed by pathological results， compared with the model group， the high-dose SFTLP group showed relieved lung lesions. The high-dose SFTLP group and the SB328437 group showed reduced CCL11 content （P<0.05）. The low- and high-dose SFTLP group， the PTX group， the SB203580 group， the PD98059 group， and the SB328437 group showed decreased CCR3 protein expression in lung tissues （P<0.05）. The high-dose SFTLP group and the PD98059 group showed reduced p-ERK level （P<0.05）. The PD98059 group showed reduced ERK level （P<0.05）. ConclusionSFTLP can inhibit airway inflammation in asthma， and the mechanism may be related to the inhibition of eosinophil activation by down-regulating CCR3 and CCL11 expression and ERK phosphorylation.

Cross-talk between CXC chemokine ligand 10-CXC chemokine receptor 3 axis and CC chemokine ligand 17-CC chemokine receptor 4 axis in the pathogenesis of oral lichen planus.

OBJECTIVES: This study aimed to determine whether a correlation existed between CXC chemokine ligand 10 (CXCL10)-CXC chemokine receptor 3 (CXCR3) and CC chemokine ligand 17 (CCL17)-CC chemokine receptor 4 (CCR4) in the pathogenesis of oral lichen planus (OLP). METHODS: Peripheral blood of OLP patients (non-erosive and erosive groups) and healthy controls were collected, and T cells were isolated and purified. T cells were co-cultured with three groups: blank, anti-CXCR3, and anti-CCR4. CXCR3 and CCR4 expression were detected by flow cytometry, and CXCL10 and CCL17 were detected by enzyme-linked immunosorbent assay, respectively. RESULTS: The purities of T cells were all >95% in the three groups (P>0.05). Receptor expression showed that CXCR3 and CCR4 in the anti-CXCR3 group was downregulated in OLP compared with the blank group (P>0.05). The level of CCR4 in the anti-CCR4 group was significantly downregulated (P<0.05), and CXCR3 was upregulated (P>0.05). Ligand analysis results showed that CXCL10 in the anti-CXCR3 group was significantly downregulated in OLP compared with the blank group (P<0.05), and CCL17 was also downregulated (P>0.05). CCL17 in the anti-CCR4 group was significantly downregulated (P<0.05), and CXCL10 was upregulated (P>0.05). The trend of receptors and ligands in controls was consistent with OLP, but no significant difference existed between the antagonistic and the blank groups (P>0.05). CONCLUSIONS: Two axes interact with each other in the pathogenesis of OLP and may play different roles in its occurrence and development.

Role of the CXCR3­mediated TLRs/MyD88 signaling pathway in promoting the development of hepatitis B into cirrhosis and liver cancer.

Chronic hepatitis B can lead to liver cirrhosis and primary hepatocellular carcinoma. The present study aimed to investigate whether C­X­C motif chemokine receptor 3 (CXCR3) regulates the genes in Toll­like receptors (TLRs)/myeloid differentiation primary response protein 88 (MyD88) signaling pathway in the development of hepatitis B into cirrhosis and liver cancer in vitro. A hepatitis B virus (HBV) overexpression lentivirus was constructed and infected into a LX­2 cell line to obtain stable HBV­overexpressing cells (named HBV­LX­2 cells). The CXCR3 gene was knocked down using small interfering RNA in HBV­LX­2 cells. Cell Counting Kit­8 assays, cell scratch tests and flow cytometry were used to detect cell proliferation, migration and apoptosis, respectively. The levels of IL­1ß and IL­6 in serum samples of patients with liver cancer were measured via ELISA, and the collagen content in liver cancer tissues was detected using Masson staining. Western blotting was used to detect the expression levels of proteins in the TLRs/MyD88 signaling pathway. Excessive fibrosis was identified in the liver cancer tissues, and the serum levels of IL­6 and IL­1ß were abnormally increased in patients with liver cancer. It was found that interfering with CXCR3 inhibited cell proliferation and migration, as well as promoted the apoptosis of HBV­LX­2 cells. Moreover, interfering with CXCR3 inhibited the expression levels of collagen type I α 1 chain and the proteins in the TLRs/MyD88 pathway. In conclusion, CXCR3 knockdown could inhibit the expression levels of proteins in the TLR4/MyD88 signaling pathway, decrease cell proliferation and migration, and promote cell apoptosis, thus inhibiting the development of liver cirrhosis to liver cancer.

CXCR3 alleviates renal ischemia­reperfusion injury via increase of Tregs.

Increasing evidence has demonstrated that regulatory T cells (Tregs) suppress innate immunity, as well as protect the kidneys from ischemia­reperfusion injury (IRI) and offer a potentially effective strategy to prevent or alleviate renal IRI. The present study explored whether C­X­C motif chemokine receptor 3 (CXCR3) alleviated renal IRI by increasing Tregs. Male C57BL/6J mice were divided into sham­surgery, IRI, CXCR3 overexpression (OE­CXCR3)+IRI, PC61+IRI and OE­CXCR3+PC61+IRI groups. Histopathological examination of the kidney was carried out using hematoxylin­eosin and Masson staining. The levels of serum creatinine (Scr) and blood urea nitrogen (BUN) were measured. Blood and kidney levels of IL­6, TNF­α, C­C motif chemokine ligand (CCL)­2 and IL­10 were detected by ELISA and western blotting. The levels of superoxide dismutase (SOD), glutathione peroxidase (GSH­Px) and malondialdehyde (MDA) in kidney tissues were also measured to assess oxidative stress. The population of Tregs in the kidney was assessed using flow cytometry. The results demonstrated that administration of OE­CXCR3 to IRI mice significantly decreased the levels of Scr, BUN, IL­6, TNF­α, CCL­2 and MDA, increased the levels of IL­10, SOD and GSH­Px, and mitigated the morphologic injury and fibrosis induced by IR compared with the IRI group. In addition, administration of OE­CXCR3 induced significant reductions in the expression levels of fibrosis­related markers, including fibronectin and type IV collagen, and increased the number of Tregs. These roles of OE­CXCR3 were significantly neutralized following deletion of Tregs with PC61 (anti­CD25 antibody). Together, the present study demonstrated that injection of OE­CXCR3 lentiviral vectors into animal models can alleviate renal IRI by increasing the number of Tregs. The results may be a promising approach for the treatment of renal IRI.