Chemokines: a new classification system and their role in immunity

Performance of urinary C-C motif chemokine ligand 14 for the prediction of persistent acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Urinary C-C motif chemokine ligand 14 (CCL14) has been described as an effective marker for delayed recovery of acute kidney injury (AKI), yet its efficacy has been found to vary between different trials. The goal of this research was to assess the predictive performance of urinary CCL14 as a marker for persistent AKI.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched the PubMed, Embase, and Cochrane databases up to April 2023 for studies of adults (> 18 years) that reported the diagnostic performance of urinary CCL14. The sensitivity, specificity, number of events, true positive, and false positive results were extracted and evaluated. Hierarchical summary receiver operating characteristic curves (HSROCs) were used to summarize the pooled test performance, and the Grading of Recommendations, Assessment, Development and Evaluations criteria were used to appraise the quality of evidence.

RESULTS

We included six studies with 952 patients in this meta-analysis. The occurrence of persistent AKI among these patients was 39.6% (377/952). The pooled sensitivity and specificity results of urinary CCL14 in predicting persistent AKI were 0.81 (95% CI 0.72-0.87) and 0.71 (95% CI 0.53-0.84), respectively. The pooled positive likelihood ratio (LR) was 2.75 (95% CI 1.63-4.66), and the negative LR was 0.27 (95% CI 0.18-0.41). The HSROC with pooled diagnostic accuracy was 0.84.

CONCLUSION

Our results suggest that urinary CCL14 can be used as an effective marker for predicting persistent AKI.

Advances in the Xenopus immunome: Diversification, expansion, and contraction

Xenopus is a genus of African clawed frogs including two species, X. tropicalis and X. laevis that are extensively used in experimental biology, immunology, and biomedical studies. The availability of fully sequenced and annotated Xenopus genomes is strengthening genome-wide analyses of gene families and transgenesis to model human diseases. However, inaccuracies in genome annotation for genes involved in the immune system (i.e., immunome) hamper immunogenetic studies. Furthermore, advanced genome technologies (e.g., single-cell and RNA-Seq) rely on well-annotated genomes. The annotation problems of Xenopus immunome include a lack of established orthology across taxa, merged gene models, poor representation in gene pages on Xenbase, misannotated genes and missing gene IDs. The Xenopus Research Resource for Immunobiology in collaboration with Xenbase and a group of investigators are working to resolve these issues in the latest versions of genome browsers. In this review, we summarize the current problems of previously misannotated gene families that we have recently resolved. We also highlight the expansion, contraction, and diversification of previously misannotated gene families.

Targeting Members of the Chemokine Family as a Novel Approach to Treating Neuropathic Pain

Neuropathic pain is a debilitating condition that affects millions of people worldwide. Numerous studies indicate that this type of pain is a chronic condition with a complex mechanism that tends to worsen over time, leading to a significant deterioration in patients' quality of life and issues like depression, disability, and disturbed sleep. Presently used analgesics are not effective enough in neuropathy treatment and may cause many side effects due to the high doses needed. In recent years, many researchers have pointed to the important role of chemokines not only in the development and maintenance of neuropathy but also in the effectiveness of analgesic drugs. Currently, approximately 50 chemokines are known to act through 20 different seven-transmembrane G-protein-coupled receptors located on the surface of neuronal, glial, and immune cells. Data from recent years clearly indicate that more chemokines than initially thought (CCL1/2/3/5/7/8/9/11, CXCL3/9/10/12/13/14/17; XCL1, CX3CL1) have pronociceptive properties; therefore, blocking their action by using neutralizing antibodies, inhibiting their synthesis, or blocking their receptors brings neuropathic pain relief. Several of them (CCL1/2/3/7/9/XCL1) have been shown to be able to reduce opioid drug effectiveness in neuropathy, and neutralizing antibodies against them can restore morphine and/or buprenorphine analgesia. The latest research provides irrefutable evidence that chemokine receptors are promising targets for pharmacotherapy; chemokine receptor antagonists can relieve pain of different etiologies, and most of them are able to enhance opioid analgesia, for example, the blockade of CCR1 (J113863), CCR2 (RS504393), CCR3 (SB328437), CCR4 (C021), CCR5 (maraviroc/AZD5672/TAK-220), CXCR2 (NVPCXCR220/SB225002), CXCR3 (NBI-74330/AMG487), CXCR4 (AMD3100/AMD3465), and XCR1 (vMIP-II). Recent research has shown that multitarget antagonists of chemokine receptors, such as CCR2/5 (cenicriviroc), CXCR1/2 (reparixin), and CCR2/CCR5/CCR8 (RAP-103), are also very effective painkillers. A multidirectional strategy based on the modulation of neuronal-glial-immune interactions by changing the activity of the chemokine family can significantly improve the quality of life of patients suffering from neuropathic pain. However, members of the chemokine family are still underestimated pharmacological targets for pain treatment. In this article, we review the literature and provide new insights into the role of chemokines and their receptors in neuropathic pain.

GPR182 is a broadly scavenging atypical chemokine receptor influencing T-independent immunity

Immune responses highly depend on the effective trafficking of immune cells into and within secondary lymphoid organs (SLOs). Atypical chemokine receptors (ACKRs) scavenge chemokines to eliminate them from the extracellular space, thereby generating gradients that guide leukocytes. In contrast to canonical chemokine receptors, ACKRs do not induce classical intracellular signaling that results in cell migration. Recently, the closest relative of ACKR3, GPR182, has been partially deorphanized as a potential novel ACKR. We confirm and extend previous studies by identifying further ligands that classify GPR182 as a broadly scavenging chemokine receptor. We validate the "atypical" nature of the receptor, wherein canonical G-protein-dependent intracellular signaling is not activated following ligand stimulation. However, β-arrestins are required for ligand-independent internalization and chemokine scavenging whereas the C-terminus is in part dispensable. In the absence of GPR182 in vivo, we observed elevated chemokine levels in the serum but also in SLO interstitium. We also reveal that CXCL13 and CCL28, which do not bind any other ACKR, are bound and efficiently scavenged by GPR182. Moreover, we found a cooperative relationship between GPR182 and ACKR3 in regulating serum CXCL12 levels, and between GPR182 and ACKR4 in controlling CCL20 levels. Furthermore, we unveil a new phenotype in GPR182-KO mice, in which we observed a reduced marginal zone (MZ), both in size and in cellularity, and thus in the T-independent antibody response. Taken together, we and others have unveiled a novel, broadly scavenging chemokine receptor, which we propose should be named ACKR5.

Heterodimers Are an Integral Component of Chemokine Signaling Repertoire

Chemokines are a family of signaling proteins that play a crucial role in cell-cell communication, cell migration, and cell trafficking, particularly leukocytes, under both normal and pathological conditions. The oligomerization state of chemokines influences their biological activity. The heterooligomerization occurs when multiple chemokines spatially and temporally co-localize, and it can significantly affect cellular responses. Recently, obligate heterodimers have emerged as tools to investigate the activities and molecular mechanisms of chemokine heterodimers, providing valuable insights into their functional roles. This review focuses on the latest progress in understanding the roles of chemokine heterodimers and their contribution to the functioning of the chemokine network.

CCL24 regulates biliary inflammation and fibrosis in primary sclerosing cholangitis

ˆCCL24 is a pro-fibrotic, pro-inflammatory chemokine expressed in several chronic fibrotic diseases. In the liver, CCL24 plays a role in fibrosis and inflammation, and blocking CCL24 led to reduced liver injury in experimental models. We studied the role of CCL24 in primary sclerosing cholangitis (PSC) and evaluated the potential therapeutic effect of blocking CCL24 in this disease. Multidrug resistance gene 2-knockout (Mdr2-/-) mice demonstrated CCL24 expression in liver macrophages and were used as a relevant experimental PSC model. CCL24-neutralizing monoclonal antibody, CM-101, significantly improved inflammation, fibrosis, and cholestasis-related markers in the biliary area. Moreover, using spatial transcriptomics, we observed reduced proliferation and senescence of cholangiocytes following CCL24 neutralization. Next, we demonstrated that CCL24 expression was elevated under pro-fibrotic conditions in primary human cholangiocytes and macrophages, and it induced proliferation of primary human hepatic stellate cells and cholangiocytes, which was attenuated following CCL24 inhibition. Correspondingly, CCL24 was found to be highly expressed in liver biopsies of patients with PSC. CCL24 serum levels correlated with Enhanced Liver Fibrosis score, most notably in patients with high alkaline phosphatase levels. These results suggest that blocking CCL24 may have a therapeutic effect in patients with PSC by reducing liver inflammation, fibrosis, and cholestasis.

Role of the CXCR6/CXCL16 axis in autoimmune diseases

The C-X-C motif ligand 16, or CXCL16, is a chemokine that belongs to the ELR - CXC subfamily. Its function is to bind to the chemokine receptor CXCR6, which is a G protein-coupled receptor with 7 transmembrane domains. The CXCR6/CXCL16 axis has been linked to the development of numerous autoimmune diseases and is connected to clinical parameters that reflect disease severity, activity, and prognosis in conditions such as multiple sclerosis, autoimmune hepatitis, rheumatoid arthritis, Crohn's disease, and psoriasis. CXCL16 is expressed in various immune cells, such as dendritic cells, monocytes, macrophages, and B cells. During autoimmune diseases, CXCL16 can facilitate the adhesion of immune cells like monocytes, T cells, NKT cells, and others to endothelial cells and dendritic cells. Additionally, sCXCL16 can regulate the migration of CXCR6-expressing leukocytes, which includes CD8⁺ T cells, CD4⁺ T cells, NK cells, constant natural killer T cells, plasma cells, and monocytes. Further investigation is required to comprehend the intricate interactions between chemokines and the pathogenesis of autoimmune diseases. It remains to be seen whether the CXCR6/CXCL16 axis represents a new target for the treatment of these conditions.

Chemokine Levels among Patients with Middle East Respiratory Syndrome Coronavirus Infection

Middle East respiratory syndrome coronavirus (MERS-CoV) is associated with significant morbidity and mortality due to intense pulmonary inflammation. Enhanced chemokine-mediated leukocyte infiltration in lungs has been linked with unfavorable outcomes with respect to the disease. This cross-sectional study assessed the levels of chemokines among 46 MERS-CoV-infected patients (19 asymptomatic and 27 symptomatic) and 52 healthy controls using a customized Luminex human chemokine magnetic multiplex panel. The plasma levels of interferon-inducible protein (IP)-10 (568.5 ± 114.7 vs. 55.19 ± 5.85 pg/mL; p < 0.0001), macrophage inflammatory protein (MIP)-1 alpha (MIP-1A) (30.78 ± 2.81 vs. 18.16 ± 0.91 pg/mL; p < 0.0001), MIP-1B (36.63 ± 4.25 vs. 25.26 ± 1.51 pg/mL; p < 0.003), monocyte chemoattractant protein (MCP)-1 (1267 ± 309.5 vs. 390.0 ± 35.51 pg/mL; p < 0.0002), and monokine-induced gamma interferon (MIG) (28.96 ± 3.93 vs. 16.29 ± 1.69 pg/mL; p < 0.001), interleukin (IL)-8 (147.9 ± 21.57 vs. 84.63 ± 10.62 pg/mL; p < 0.004) were significantly higher in symptomatic patients than healthy controls. Likewise, the levels of IP-10 (247.6 ± 80.09 vs. 55.19 ± 5.85 pg/mL; p < 0.0002) and MCP-1 (650.7 ± 149 pg/mL vs. 390 ± 35.51 pg/mL; p < 0.02) were also significantly higher in asymptomatic patients compared to healthy controls. However, no differences were observed in the plasma levels of MIP-1A, MIP-1B, MIG, and IL-8 between asymptomatic patients and uninfected controls. Conversely, the mean plasma levels of regulated on activation normal T cell expressed and secreted (RANTES) (3039 ± 301.0 vs. 4390 ± 223 pg/mL; p < 0.001) and eotaxin (176.9 ± 30.20 vs. 296.2 ± 28.11 pg/mL; p < 0.01) were significantly lower in symptomatic MERS-CoV-infected patients compared to healthy controls. Likewise, the levels of eotaxin (162.7 ± 21.60 vs. 296.2 ± 28.11 pg/mL; p < 0.01) were also significantly lower in asymptomatic patients. Interestingly, the level of MCP-1 (2139 ± 548.2 vs. 776.5 ± 165.3 pg/mL; p < 0.004) was significantly higher in deceased symptomatic patients compared to recovered symptomatic patients. MCP-1 was the only chemokine associated with a higher risk of mortality. Symptomatic MERS-CoV-infected patients had a significant elevation of plasma chemokines and elevated MCP-1 levels were found to be associated with fatal outcomes.

Gene-edited and -engineered stem cell platform drives immunotherapy for brain metastatic melanomas

Oncolytic virus therapy has shown activity against primary melanomas; however, its efficacy in brain metastases remains challenging, mainly because of the delivery and immunosuppressive nature of tumors in the brain. To address this challenge, we first established PTEN-deficient melanoma brain metastasis mouse models and characterized them to be more immunosuppressive compared with primary melanoma, mimicking the clinical settings. Next, we developed an allogeneic twin stem cell (TSC) system composed of two tumor-targeting stem cell (SC) populations. One SC was loaded with oncolytic herpes simplex virus (oHSV), and the other SC was CRISPR-Cas9 gene-edited to knock out nectin 1 (N1) receptor (N1KO) to acquire resistance to oHSV and release immunomodulators, such as granulocyte-macrophage colony-stimulating factor (GM-CSF). Using mouse models of brain metastatic BRAFV600E/PTEN-/- and BRAFV600E/wt/PTEN-/- mutant melanomas, we show that locoregional delivery of TSCs releasing oHSV and GM-CSF (TSC-G) activated dendritic cell- and T cell-mediated immune responses. In addition, our strategy exhibited greater therapeutic efficacy when compared with the existing oncolytic viral therapeutic approaches. Moreover, the TSCs composed of SC-oHSV and SCN1KO-releasing GM-CSF and single-chain variable fragment anti-PD-1 (TSC-G/P) had therapeutic efficacy in both syngeneic and patient-derived humanized mouse models of leptomeningeal metastasis. Our findings provide a promising allogeneic SC-based immunotherapeutic strategy against melanomas in the CNS and a road map toward clinical translation.

Chemokine CCL6 Plays Key Role in the Inhibitory Effect of Vitamin A on Norovirus Infection

Norovirus (NoV) is the most common viral cause of acute gastroenteritis worldwide. Vitamin A has demonstrated the potential to protect against gastrointestinal infections. However, the effects of vitamin A on human norovirus (HuNoV) infections remain poorly understood. This study aimed to investigate how vitamin A administration affects NoV replication. We demonstrated that treatment with retinol or retinoic acid (RA) inhibited NoV replication in vitro based on their effects on HuNoV replicon-bearing cells and murine norovirus-1 (MNV-1) replication in murine cells. MNV replication in vitro showed significant transcriptomic changes, which were partially reversed by retinol treatment. RNAi knockdown of CCL6, a chemokine gene that was downregulated by MNV infection but upregulated by retinol administration, resulted in increased MNV replication in vitro. This suggested a role of CCL6 in the host response to MNV infections. Similar gene expression patterns were observed in the murine intestine after oral administration of RA and/or MNV-1.CW1. CCL6 directly decreased HuNoV replication in HG23 cells, and might indirectly regulate the immune response against NoV infection. Finally, relative replication levels of MNV-1.CW1 and MNV-1.CR6 were significantly increased in CCL6 knockout RAW 264.7 cells. This study is the first to comprehensively profile transcriptomes in response to NoV infection and vitamin A treatment in vitro, and thus may provide new insights into dietary prophylaxis and NoV infections.

The chemokine monocyte chemoattractant protein-1/CCL2 is a promoter of breast cancer metastasis

Breast cancer is the most prevalent cancer worldwide, and metastasis is the leading cause of death in cancer patients. Human monocyte chemoattractant protein-1 (MCP-1/CCL2) was isolated from the culture supernatants of not only mitogen-activated peripheral blood mononuclear leukocytes but also malignant glioma cells based on its in vitro chemotactic activity toward human monocytes. MCP-1 was subsequently found to be identical to a previously described tumor cell-derived chemotactic factor thought to be responsible for the accumulation of tumor-associated macrophages (TAMs), and it became a candidate target of clinical intervention; however, the role of TAMs in cancer development was still controversial at the time of the discovery of MCP-1. The in vivo role of MCP-1 in cancer progression was first evaluated by examining human cancer tissues, including breast cancers. Positive correlations between the level of MCP-1 production in tumors and the degree of TAM infiltration and cancer progression were established. The contribution of MCP-1 to the growth of primary tumors and metastasis to the lung, bone, and brain was examined in mouse breast cancer models. The results of these studies strongly suggested that MCP-1 is a promoter of breast cancer metastasis to the lung and brain but not bone. Potential mechanisms of MCP-1 production in the breast cancer microenvironment have also been reported. In the present manuscript, we review studies in which the role of MCP-1 in breast cancer development and progression and the mechanisms of its production were examined and attempt to draw a consensus and discuss the potential use of MCP-1 as a biomarker for diagnosis.

New genetic and epigenetic insights into the chemokine system: the latest discoveries aiding progression toward precision medicine

Over the past thirty years, the importance of chemokines and their seven-transmembrane G protein-coupled receptors (GPCRs) has been increasingly recognized. Chemokine interactions with receptors trigger signaling pathway activity to form a network fundamental to diverse immune processes, including host homeostasis and responses to disease. Genetic and nongenetic regulation of both the expression and structure of chemokines and receptors conveys chemokine functional heterogeneity. Imbalances and defects in the system contribute to the pathogenesis of a variety of diseases, including cancer, immune and inflammatory diseases, and metabolic and neurological disorders, which render the system a focus of studies aiming to discover therapies and important biomarkers. The integrated view of chemokine biology underpinning divergence and plasticity has provided insights into immune dysfunction in disease states, including, among others, coronavirus disease 2019 (COVID-19). In this review, by reporting the latest advances in chemokine biology and results from analyses of a plethora of sequencing-based datasets, we outline recent advances in the understanding of the genetic variations and nongenetic heterogeneity of chemokines and receptors and provide an updated view of their contribution to the pathophysiological network, focusing on chemokine-mediated inflammation and cancer. Clarification of the molecular basis of dynamic chemokine-receptor interactions will help advance the understanding of chemokine biology to achieve precision medicine application in the clinic.

Multi-omics integration analysis of GPCRs in pan-cancer to uncover inter-omics relationships and potential driver genes

G protein-coupled receptors (GPCRs) are the largest drug target family. Unfortunately, applications of GPCRs in cancer therapy are scarce due to very limited knowledge regarding their correlations with cancers. Multi-omics data enables systematic investigations of GPCRs, yet their effective integration remains a challenge due to the complexity of the data. Here, we adopt two types of integration strategies, multi-staged and meta-dimensional approaches, to fully characterize somatic mutations, somatic copy number alterations (SCNAs), DNA methylations, and mRNA expressions of GPCRs in 33 cancers. Results from the multi-staged integration reveal that GPCR mutations cannot well predict expression dysregulation. The correlations between expressions and SCNAs are primarily positive, while correlations of the methylations with expressions and SCNAs are bimodal with negative correlations predominating. Based on these correlations, 32 and 144 potential cancer-related GPCRs driven by aberrant SCNA and methylation are identified, respectively. In addition, the meta-dimensional integration analysis is carried out by using deep learning models, which predict more than one hundred GPCRs as potential oncogenes. When comparing results between the two integration strategies, 165 cancer-related GPCRs are common in both, suggesting that they should be prioritized in future studies. However, 172 GPCRs emerge in only one, indicating that the two integration strategies should be considered concurrently to complement the information missed by the other such that obtain a more comprehensive understanding. Finally, correlation analysis further reveals that GPCRs, in particular for the class A and adhesion receptors, are generally immune-related. In a whole, the work is for the first time to reveal the associations between different omics layers and highlight the necessity of combing the two strategies in identifying cancer-related GPCRs.

Atlas of the anatomical localization of atypical chemokine receptors in healthy mice

Atypical chemokine receptors (ACKRs) scavenge chemokines and can contribute to gradient formation by binding, internalizing, and delivering chemokines for lysosomal degradation. ACKRs do not couple to G-proteins and fail to induce typical signaling induced by chemokine receptors. ACKR3, which binds and scavenges CXCL12 and CXCL11, is known to be expressed in vascular endothelium, where it has immediate access to circulating chemokines. ACKR4, which binds and scavenges CCL19, CCL20, CCL21, CCL22, and CCL25, has also been detected in lymphatic and blood vessels of secondary lymphoid organs, where it clears chemokines to facilitate cell migration. Recently, GPR182, a novel ACKR-like scavenger receptor, has been identified and partially deorphanized. Multiple studies point towards the potential coexpression of these 3 ACKRs, which all interact with homeostatic chemokines, in defined cellular microenvironments of several organs. However, an extensive map of ACKR3, ACKR4, and GPR182 expression in mice has been missing. In order to reliably detect ACKR expression and coexpression, in the absence of specific anti-ACKR antibodies, we generated fluorescent reporter mice, ACKR3GFP/+, ACKR4GFP/+, GPR182mCherry/+, and engineered fluorescently labeled ACKR-selective chimeric chemokines for in vivo uptake. Our study on young healthy mice revealed unique and common expression patterns of ACKRs in primary and secondary lymphoid organs, small intestine, colon, liver, and kidney. Furthermore, using chimeric chemokines, we were able to detect distinct zonal expression and activity of ACKR4 and GPR182 in the liver, which suggests their cooperative relationship. This study provides a broad comparative view and a solid stepping stone for future functional explorations of ACKRs based on the microanatomical localization and distinct and cooperative roles of these powerful chemokine scavengers.

Systemic lupus erythematosus and thyroid disease: a Mendelian randomization study

OBJECTIVES

To clarify the controversy between systemic lupus erythematosus (SLE) and thyroid disease, our study was designed to determine whether or not thyroid problems are associated with SLE.

METHODS

We obtained the IEU GWAS database for summary information on genome-wide association studies (GWAS) of SLE and thyroid disease (hypothyroidism and hyperthyroidism) in people with European ancestry. Three approaches were employed to assess the causal link between SLE and thyroid disease: MR-Egger, weighted median (WM), and inverse variance weighted (IVW). The pleiotropy and heterogeneity were examined using a variety of techniques, including the MR-Egger intercept, the MR-PRESSO approach, and the Cochran's Q test.

RESULTS

MR analysis revealed a relationship between SLE and an elevated incidence of hypothyroidism (IVW OR: 1.004, 95% CI: [1.003, 1.005], P = 8.45E-16) and hyperthyroidism (IVW OR: 1.0009, 95% CI: [1.0005, 1.0010], P = 1.30E-5). Neither horizontal pleiotropy nor heterogeneity was detected in the sensitivity analysis.

CONCLUSION

Our MR study presents strong evidence demonstrating a link between SLE and an elevated risk of thyroid illness. This could help us learn more about what causes SLE and give people with SLE more thorough thyroid function tests and evaluations. Key points • We did not discover modest heterogeneity and pleiotropy in our study. •The findings of this study indicate that SLE is related to an elevated risk of hypothyroidism and hyperthyroidism.

Identification of diagnostic biomarks and immune cell infiltration in ulcerative colitis

We aimed to explore diagnostic biomarks and immune cell infiltration characteristics in ulcerative colitis (UC). We used the dataset GSE38713 as the training set and dataset GSE94648 as the test set. A total of 402 differentially expressed genes (DEGs) were obtained from GSE38713. Annotating, visualizing, and integrating discovery of these differential genes was performed using Gene Ontology (GO), Kyoto Gene and Genome Encyclopedia Pathway (KEGG), and Gene Set Enrichment Analysis (GSEA). Protein-protein interaction networks were constructed from the STRING database, and protein functional modules were identified using the CytoHubba plugin of Cytoscape. Random forest and LASSO regression were used to screen for UC-related diagnostic markers, and ROC curves were generated to validate their diagnostic value. The composition of 22 immune cells was analyzed, and the immune cell infiltration in UC was analyzed using CIBERSORT. Results: Seven diagnostic markers associated with UC were identified: TLCD3A, KLF9, EFNA1, NAAA,WDR4, CKAP4, and CHRNA1. Immune cell infiltration assessment revealed that macrophages M1, activated dendritic cells, and neutrophil cells infiltrated relatively more compared to normal control samples. Our results suggest a new functional feature of UC and suggest potential biomarkers for UC through comprehensive analysis of integrated gene expression data.

Secreted protease PRSS35 suppresses hepatocellular carcinoma by disabling CXCL2-mediated neutrophil extracellular traps

Hepatocytes function largely through the secretion of proteins that regulate cell proliferation, metabolism, and intercellular communications. During the progression of hepatocellular carcinoma (HCC), the hepatocyte secretome changes dynamically as both a consequence and a causative factor in tumorigenesis, although the full scope of secreted protein function in this process remains unclear. Here, we show that the secreted pseudo serine protease PRSS35 functions as a tumor suppressor in HCC. Mechanistically, we demonstrate that active PRSS35 is processed via cleavage by proprotein convertases. Active PRSS35 then suppresses protein levels of CXCL2 through targeted cleavage of tandem lysine (KK) recognition motif. Consequently, CXCL2 degradation attenuates neutrophil recruitment to tumors and formation of neutrophil extracellular traps, ultimately suppressing HCC progression. These findings expand our understanding of the hepatocyte secretome's role in cancer development while providing a basis for the clinical translation of PRRS35 as a therapeutic target or diagnostic biomarker.

Structural and Phylogenetic Analysis of CXCR4 Protein Reveals New Insights into Its Role in Emerging and Re-Emerging Diseases in Mammals

Chemokine receptor type 4 (CXCR4) is a G protein-coupled receptor that plays an essential role in immune system function and disease processes. Our study aims to conduct a comparative structural and phylogenetic analysis of the CXCR4 protein to gain insights into its role in emerging and re-emerging diseases that impact the health of mammals. In this study, we analyzed the evolution of CXCR4 genes across a wide range of mammalian species. The phylogenetic study showed species-specific evolutionary patterns. Our analysis revealed novel insights into the evolutionary history of CXCR4, including genetic changes that may have led to functional differences in the protein. This study revealed that the structural homologous human proteins and mammalian CXCR4 shared many characteristics. We also examined the three-dimensional structure of CXCR4 and its interactions with other molecules in the cell. Our findings provide new insights into the genomic landscape of CXCR4 in the context of emerging and re-emerging diseases, which could inform the development of more effective treatments or prevention strategies. Overall, our study sheds light on the vital role of CXCR4 in mammalian health and disease, highlighting its potential as a therapeutic target for various diseases impacting human and animal health. These findings provided insight into the study of human immunological disorders by indicating that Chemokines may have activities identical to or similar to those in humans and several mammalian species.

Targeting the chemokine ligand 2-chemokine receptor 2 axis provides the possibility of immunotherapy in chronic pain

Chronic pain affects patients' physical and psychological health and quality of life, entailing a tremendous public health challenge. Currently, drugs for chronic pain are usually associated with a large number of side effects and poor efficacy. Chemokines in the neuroimmune interface combine with their receptors to regulate inflammation or mediate neuroinflammation in the peripheral and central nervous system. Targeting chemokines and their receptor-mediated neuroinflammation is an effective means to treat chronic pain. In recent years, growing evidence has shown that the expression of chemokine ligand 2 (CCL2) and its main chemokine receptor 2 (CCR2) is involved in its occurrence, development and maintenance of chronic pain. This paper summarises the relationship between the chemokine system, CCL2/CCR2 axis, and chronic pain, and the CCL2/CCR2 axis changes under different chronic pain conditions. Targeting chemokine CCL2 and its chemokine receptor CCR2 through siRNA, blocking antibodies, or small molecule antagonists may provide new therapeutic possibilities for managing chronic pain.

Epigenetic regulation of chemokine (CC-motif) ligand 2 in inflammatory diseases

Appropriate responses to inflammation are conducive to pathogen elimination and tissue repair, while uncontrolled inflammatory reactions are likely to result in the damage of tissues. Chemokine (CC-motif) Ligand 2 (CCL2) is the main chemokine and activator of monocytes, macrophages, and neutrophils. CCL2 played a key role in amplifying and accelerating the inflammatory cascade and is closely related to chronic non-controllable inflammation (cirrhosis, neuropathic pain, insulin resistance, atherosclerosis, deforming arthritis, ischemic injury, cancer, etc.). The crucial regulatory roles of CCL2 may provide potential targets for the treatment of inflammatory diseases. Therefore, we presented a review of the regulatory mechanisms of CCL2. Gene expression is largely affected by the state of chromatin. Different epigenetic modifications, including DNA methylation, post-translational modification of histones, histone variants, ATP-dependent chromatin remodelling, and non-coding RNA, could affect the 'open' or 'closed' state of DNA, and then significantly affect the expression of target genes. Since most epigenetic modifications are proven to be reversible, targeting the epigenetic mechanisms of CCL2 is expected to be a promising therapeutic strategy for inflammatory diseases. This review focuses on the epigenetic regulation of CCL2 in inflammatory diseases.

A review of the pleiotropic actions of the IFN-inducible CXC chemokine receptor 3 ligands in the synovial microenvironment

Chemokines are pivotal players in instigation and perpetuation of synovitis through leukocytes egress from the blood circulation into the inflamed articulation. Multitudinous literature addressing the involvement of the dual-function interferon (IFN)-inducible chemokines CXCL9, CXCL10 and CXCL11 in diseases characterized by chronic inflammatory arthritis emphasizes the need for detangling their etiopathological relevance. Through interaction with their mutual receptor CXC chemokine receptor 3 (CXCR3), the chemokines CXCL9, CXCL10 and CXCL11 exert their hallmark function of coordinating directional trafficking of CD4+ TH1 cells, CD8+ T cells, NK cells and NKT cells towards inflammatory niches. Among other (patho)physiological processes including infection, cancer, and angiostasis, IFN-inducible CXCR3 ligands have been implicated in autoinflammatory and autoimmune diseases. This review presents a comprehensive overview of the abundant presence of IFN-induced CXCR3 ligands in bodily fluids of patients with inflammatory arthritis, the outcomes of their selective depletion in rodent models, and the attempts at developing candidate drugs targeting the CXCR3 chemokine system. We further propose that the involvement of the CXCR3 binding chemokines in synovitis and joint remodeling encompasses more than solely the directional ingress of CXCR3-expressing leukocytes. The pleotropic actions of the IFN-inducible CXCR3 ligands in the synovial niche reiteratively illustrate the extensive complexity of the CXCR3 chemokine network, which is based on the intercommunion of IFN-inducible CXCR3 ligands with distinct CXCR3 isoforms, enzymes, cytokines, and infiltrated and resident cells present in the inflamed joints.

The chemokines CXCL8 and CXCL12: molecular and functional properties, role in disease and efforts towards pharmacological intervention

Chemokines are an indispensable component of our immune system through the regulation of directional migration and activation of leukocytes. CXCL8 is the most potent human neutrophil-attracting chemokine and plays crucial roles in the response to infection and tissue injury. CXCL8 activity inherently depends on interaction with the human CXC chemokine receptors CXCR1 and CXCR2, the atypical chemokine receptor ACKR1, and glycosaminoglycans. Furthermore, (hetero)dimerization and tight regulation of transcription and translation, as well as post-translational modifications further fine-tune the spatial and temporal activity of CXCL8 in the context of inflammatory diseases and cancer. The CXCL8 interaction with receptors and glycosaminoglycans is therefore a promising target for therapy, as illustrated by multiple ongoing clinical trials. CXCL8-mediated neutrophil mobilization to blood is directly opposed by CXCL12, which retains leukocytes in bone marrow. CXCL12 is primarily a homeostatic chemokine that induces migration and activation of hematopoietic progenitor cells, endothelial cells, and several leukocytes through interaction with CXCR4, ACKR1, and ACKR3. Thereby, it is an essential player in the regulation of embryogenesis, hematopoiesis, and angiogenesis. However, CXCL12 can also exert inflammatory functions, as illustrated by its pivotal role in a growing list of pathologies and its synergy with CXCL8 and other chemokines to induce leukocyte chemotaxis. Here, we review the plethora of information on the CXCL8 structure, interaction with receptors and glycosaminoglycans, different levels of activity regulation, role in homeostasis and disease, and therapeutic prospects. Finally, we discuss recent research on CXCL12 biochemistry and biology and its role in pathology and pharmacology.

Immunity and Growth Plasticity of Asian Short-Toed Lark Nestlings in Response to Changes in Food Conditions: Can It Buffer the Challenge of Climate Change-Induced Trophic Mismatch?

Passerine nestlings frequently suffer from sub-optimal food conditions due to climate change-induced trophic mismatch between the nestlings and their optimal food resources. The ability of nestlings to buffer this challenge is less well understood. We hypothesized that poor food conditions might induce a higher immune response and lower growth rate of nestlings, and such physiological plasticity is conducive to nestling survival. To test this, we examined how food (grasshopper nymphs) abundance affects the expression of interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), interleukin-1 β (IL-1β) genes, plasma IGF-1 levels, body mass, and fledging rates in wild Asian short-toed lark (Alaudala cheleensis) nestlings. Linear mixed models revealed that nymph biomass significantly influenced the expression of IFN-γ, TNF-α, and IL-1β genes, and the level of plasma IGF-1. The expressions of IFN-γ, TNF-α, and IL-1β genes were negatively correlated with nymph biomass and plasma IGF-1 level. Plasma IGF-1 level, nestling body mass growth rate, was positively correlated with nymph biomass. Despite a positive correlation between the nestling fledge rate and nymph biomass, more than 60% of nestlings fledged when nymph biomass was at the lowest level. These results suggest that immunity and growth plasticity of nestlings may be an adaptation for birds to buffer the negative effects of trophic mismatch.

Establishment of a Sensitive Monoclonal Antibody Against Mouse CCR9 (C9Mab-24) for Flow Cytometry

The CC chemokine receptor 9 (CCR9), also known as CD199, is one of chemokine receptors. The CC chemokine ligand 25 (CCL25) is known to be the only ligand for CCR9. The CCR9-CCL25 interaction plays important roles in chemotaxis of lymphocytes and tumor cell migration. Therefore, CCR9-CCL25 axis is a promising target for tumor therapy and diagnosis. In this study, we established a sensitive and specific monoclonal antibody (mAb) against mouse CCR9 (mCCR9) using N-terminal peptide immunization method. The established anti-mCCR9 mAb, C₉Mab-24 (rat immunoglobulin [IgG]_2a, kappa), reacted with mCCR9-overexpressed Chinese hamster ovary-K1 (CHO/mCCR9) and mCCR9-endogenously expressed cell line, RL2, through flow cytometry. Kinetic analyses using flow cytometry showed that the dissociation constants (K_D) of C₉Mab-24 for CHO/mCCR9 and RL2 cell lines were 6.0 × 10^-9 M and 4.7 × 10^-10 M, respectively. Results indicated that C₉Mab-24 is useful for detecting mCCR9 through flow cytometry, thereby providing a possibility for targeting mCCR9-expressing cells in vivo experiments.

c-MYC mediates the crosstalk between breast cancer cells and tumor microenvironment

The MYC oncogenic family is dysregulated in diverse tumors which is generally linked to the poor prognosis of tumors. The members in MYC family are transcription factors which are responsible for the regulation of various genes expression. Among them, c-MYC is closely related to the progression of tumors. Furthermore, c-MYC aberrations is tightly associated with the prevalence of breast cancer. Tumor microenvironment (TME) is composed of many different types of cellular and non-cellular factors, mainly including cancer-associated fibroblasts, tumor-associated macrophages, vascular endothelial cells, myeloid-derived suppressor cells and immune cells, all of which can affect the diagnosis, prognosis, and therapeutic efficacy of breast cancer. Importantly, the biological processes occurred in TME, such as angiogenesis, immune evasion, invasion, migration, and the recruition of stromal and tumor-infiltrating cells are under the modulation of c-MYC. These findings indicated that c-MYC serves as a critical regulator of TME. Here, we aimed to summarize and review the relevant research, thus to clarify c-MYC is a key mediator between breast cancer cells and TME. Video Abstract.

Studies with neutralizing antibodies suggest CXCL8-mediated neutrophil activation is independent of C-C motif chemokine receptor-like 2 (CCRL2) ligand binding function

C-C motif chemokine receptor-like 2 (CCRL2) is a non-signaling 7 transmembrane receptor that binds chemotactic ligands to shape leukocyte recruitment to sites of inflammation. However, there is a lack of consensus on the ligands that directly bind CCRL2 or their functional impact. Studies with CCRL2 knockout mice have demonstrated that neutrophils have impaired degranulation and migration in response to CXCL8, where the underlying molecular mechanism is proposed to be due to the formation of CCRL2 heterodimers with the chemokine receptor CXCR2. Herein, we characterized the ligands that bind directly to CCRL2 and interrogated the impact of CCRL2 neutralization on CXCL8 signaling in neutrophils using pharmacological antibody tools. Using flow cytometry and Surface Plasmon Resonance microscopy (SPRm) cell binding experiments, we confirmed that chemerin, but not previously reported C-C chemokines, binds CCRL2. Furthermore, we identified human and mouse CCRL2 antibodies that neutralized chemerin binding to CCRL2. Unexpectedly, we found that neutralization of CCRL2 with these antibodies did not attenuate CXCL8-induced human neutrophil degranulation nor CXCL8-induced murine neutrophil recruitment to the peritoneum. Based on the observed differences in modulating CCRL2 function with neutralizing antibodies compared to the reported CCRL2 deficient murine models, we hypothesize that the ligand binding function of CCRL2 is dispensable for CXCL8 signaling in neutrophils. Finally, extensive profiling of CCRL2 expression on peripheral blood leukocytes revealed monocytes, dendritic cells (DC), and subpopulations of natural killer T (NKT) cells as additional targets, highlighting potential roles for CCRL2 in human cell types beyond neutrophils that warrants future investigation.

Advances in Lung Cancer Treatment Using Nanomedicines

Carcinoma of the lungs is among the most menacing forms of malignancy and has a poor prognosis, with a low overall survival rate due to delayed detection and ineffectiveness of conventional therapy. Therefore, drug delivery strategies that may overcome undesired damage to healthy cells, boost therapeutic efficacy, and act as imaging tools are currently gaining much attention. Advances in material science have resulted in unique nanoscale-based theranostic agents, which provide renewed hope for patients suffering from lung cancer. Nanotechnology has vastly modified and upgraded the existing techniques, focusing primarily on increasing bioavailability and stability of anti-cancer drugs. Nanocarrier-based imaging systems as theranostic tools in the treatment of lung carcinoma have proven to possess considerable benefits, such as early detection and targeted therapeutic delivery for effectively treating lung cancer. Several variants of nano-drug delivery agents have been successfully studied for therapeutic applications, such as liposomes, dendrimers, polymeric nanoparticles, nanoemulsions, carbon nanotubes, gold nanoparticles, magnetic nanoparticles, solid lipid nanoparticles, hydrogels, and micelles. In this Review, we present a comprehensive outline on the various types of overexpressed receptors in lung cancer, as well as the various targeting approaches of nanoparticles.

XCL1, a serum biomarker in neurological diseases; HTLV-1-associated myelopathy and multiple sclerosis

The XCL1-XCR1 axis has a potential role in the recruitment of immune cells to the site of inflammation. The present study aimed to examine the relation of XCL1 serum levels with Multiple sclerosis (MS) and HTLV-1-associated myelopathy (HAM), as chronic inflammatory diseases of the central nervous system (CNS). DNA was extracted to evaluate HTLV-1 proviral load (PVL) using real-time PCR. Serum levels of XCL1 was determined by using an ELISA assay. The serum level of XCL1 was significantly higher in patients with HAM than that of asymptomatic carriers (ACs) and healthy controls (HCs) (p < 0.001 and p < 0.0001, respectively) and was also higher in MS patients compared to HCs (p < 0.0001). Moreover, the concentration of XCL1 serum level was significantly different between the ACs and HCs group (p < 0.0001). In conclusion, increased expression of XCL1 might contribute to the migration of autoreactive T cells to the central nervous system and play a critical role in the development and pathogenesis of inflammatory neurological diseases including HAM and MS.

Evolution of developmental and comparative immunology in poultry: The regulators and the regulated

Avian has a unique immune system that evolved in response to environmental pressures in all aspects of innate and adaptive immune responses, including localized and circulating lymphocytes, diversity of immunoglobulin repertoire, and various cytokines and chemokines. All of these attributes make birds an indispensable vertebrate model for studying the fundamental immunological concepts and comparative immunology. However, research on the immune system in birds lags far behind that of humans, mice, and other agricultural animal species, and limited immune tools have hindered the adequate application of birds as disease models for mammalian systems. An in-depth understanding of the avian immune system relies on the detailed studies of various regulated and regulatory mediators, such as cell surface antigens, cytokines, and chemokines. Here, we review current knowledge centered on the roles of avian cell surface antigens, cytokines, chemokines, and beyond. Moreover, we provide an update on recent progress in this rapidly developing field of study with respect to the availability of immune reagents that will facilitate the study of regulatory and regulated components of poultry immunity. The new information on avian immunity and available immune tools will benefit avian researchers and evolutionary biologists in conducting fundamental and applied research.

New pairings and deorphanization among the atypical chemokine receptor family - physiological and clinical relevance

Atypical chemokine receptors (ACKRs) form a small subfamily of receptors (ACKR1-4) unable to trigger G protein-dependent signaling in response to their ligands. They do, however, play a crucial regulatory role in chemokine biology by capturing, scavenging or transporting chemokines, thereby regulating their availability and signaling through classical chemokine receptors. ACKRs add thus another layer of complexity to the intricate chemokine-receptor interaction network. Recently, targeted approaches and screening programs aiming at reassessing chemokine activity towards ACKRs identified several new pairings such as the dimeric CXCL12 with ACKR1, CXCL2, CXCL10 and CCL26 with ACKR2, the viral broad-spectrum chemokine vCCL2/vMIP-II, a range of opioid peptides and PAMP-12 with ACKR3 as well as CCL20 and CCL22 with ACKR4. Moreover, GPR182 (ACKR5) has been lately proposed as a new promiscuous atypical chemokine receptor with scavenging activity notably towards CXCL9, CXCL10, CXCL12 and CXCL13. Altogether, these findings reveal new degrees of complexity of the chemokine network and expand the panel of ACKR ligands and regulatory functions. In this minireview, we present and discuss these new pairings, their physiological and clinical relevance as well as the opportunities they open for targeting ACKRs in innovative therapeutic strategies.

Thirty-five years since the discovery of chemotactic cytokines, interleukin-8 and MCAF: A historical overview

Inflammation is a host defense response to various invading stimuli, but an excessive and persistent inflammatory response can cause tissue injury, which can lead to irreversible organ damage and dysfunction. Excessive inflammatory responses are believed to link to most human diseases. A specific type of leukocyte infiltration into invaded tissues is required for inflammation. Historically, the underlying molecular mechanisms of this process during inflammation were an enigma, compromising research in the fields of inflammation, immunology, and pathology. However, the pioneering discovery of chemotactic cytokines (chemokines), monocyte-derived neutrophil chemotactic factor (MDNCF; interleukin [IL]-8, CXCL8) and monocyte chemotactic and activating factor (MCAF; monocyte chemotactic factor 1 [MCP-1], CCL2) in the late 1980s finally enabled us to address this issue. In this review, we provide a historical overview of chemokine research over the last 35 years.

Role of chemokine-like factor 1 as an inflammatory marker in diseases

Immunoinflammatory mechanisms have been incrementally found to be involved in the pathogenesis of multiple diseases, with chemokines being the main drivers of immune cell infiltration in the inflammatory response. Chemokine-like factor 1 (CKLF1), a novel chemokine, is highly expressed in the human peripheral blood leukocytes and exerts broad-spectrum chemotactic and pro-proliferative effects by activating multiple downstream signaling pathways upon binding to its functional receptors. Furthermore, the relationship between CKLF1 overexpression and various systemic diseases has been demonstrated in both in vivo and in vitro experiments. In this context, it is promising that clarifying the downstream mechanism of CKLF1 and identifying its upstream regulatory sites can yield new strategies for targeted therapeutics of immunoinflammatory diseases.

The Role of CXC Chemokines in Cancer Progression

CXC chemokines are small chemotactic and secreted cytokines. Studies have shown that CXC chemokines are dysregulated in multiple types of cancer and are closely correlated with tumor progression. The CXC chemokine family has a dual function in tumor development, either tumor-promoting or tumor-suppressive depending on the context of cellular signaling. Recent evidence highlights the pro-tumorigenic properties of CXC chemokines in most human cancers. CXC chemokines were found to play pivotal roles in promoting angiogenesis, stimulating inflammatory responses, and facilitating tumor metastases. Enhanced expression of CXC chemokines is always signatured with inferior survival and prognosis. The levels of CXC chemokines in cancer patients are in dynamic change according to the tumor contexts (e.g., chemotherapy resistance and tumor recurrence after surgery). Thus, CXC chemokines have great potential to be used as diagnostic and prognostic biomarkers and therapeutic targets. Currently, the molecular mechanisms underlying the effect of CXC chemokines on tumor inflammation and metastasis remain unclear and application of antagonists and neutralizing antibodies of CXC chemokines signaling for cancer therapy is still not fully established. This article will review the roles of CXC chemokines in promoting tumorigenesis and progression and address the future research directions of CXC chemokines for cancer treatment.

The prognostic value of NLRP1/NLRP3 and its relationship with immune infiltration in human gastric cancer

BACKGROUND

Inflammasomes are related to tumorigenesis and immune-regulation. Here, we investigated the prognostic value of the NLR family pyrin domain containing (NLRP) 1/NLRP3 inflammasome and its potential mechanisms in immune-regulation in gastric cancer (GC).

METHODS

We analyzed the differential expression of NLRP1/NLRP3 between tumor and normal tissues using the Oncomine and Tumor Immune Estimate Resource (TIMER) databases. Immunohistochemistry and western blotting were used to detect NLRP1/NLRP3 protein expression in GC tissues. Correlations between NLRP1/NLRP3 expression levels and patient survival were analyzed using Kaplan-Meier survival curves. The relationships of NLRP1/NLRP3 expression and tumor-infiltrating immune cells/marker genes were assessed using the TIMER database. NLRP1/NLRP3 and immune checkpoint gene correlations were verified by single-gene co-expression analyses, and tumor immune-related pathways involving NLRP1/NLRP3 were analyzed using gene set enrichment analysis (GSEA).

RESULTS

Elevated NLRP1/NLRP3 expression was significantly correlated with lymph node metastasis, poor survival, immune-infiltrating cell abundances, and immune cell markers. NLRP3 showed stronger correlations with immune infiltration and the prognosis of gastric cancer. NLRP1 and NLRP3 might be involved in the same tumor immune-related pathways. Thus, high NLRP1/NLRP3 expression promotes immune cell infiltration and poor prognosis in GC. NLRP1/NLRP3, particularly NLRP3, may have important roles in immune infiltration and may serve as a prognostic biomarker for GC.

CONCLUSIONS

NLRP1/NLRP3, particularly NLRP3, may have important roles in immune infiltration and may serve as a prognostic biomarker for GC.

The Role of the Innate Immune System in Wear Debris-Induced Inflammatory Peri-Implant Osteolysis in Total Joint Arthroplasty

Periprosthetic osteolysis remains a leading complication of total hip and knee arthroplasty, often resulting in aseptic loosening of the implant and necessitating revision surgery. Wear-induced particulate debris is the main cause initiating this destructive process. The purpose of this article is to review recent advances in understanding of how wear debris causes osteolysis, and emergent strategies for the avoidance and treatment of this disease. A strong activator of the peri-implant innate immune this debris-induced inflammatory cascade is dictated by macrophage secretion of TNF-α, IL-1, IL-6, and IL-8, and PGE2, leading to peri-implant bone resorption through activation of osteoclasts and inhibition of osteoblasts through several mechanisms, including the RANK/RANKL/OPG pathway. Therapeutic agents against proinflammatory mediators, such as those targeting tumor necrosis factor (TNF), osteoclasts, and sclerostin, have shown promise in reducing peri-implant osteolysis in vitro and in vivo; however, radiographic changes and clinical diagnosis often lag considerably behind the initiation of osteolysis, making timely treatment difficult. Considerable efforts are underway to develop such diagnostic tools, therapies, and identify novel targets for therapeutic intervention.

Epitope Mapping of Anti-Mouse CCR3 Monoclonal Antibodies Using Flow Cytometry

The CC chemokine receptor 3 (CCR3) is a receptor for CC chemokines, including CCL5/RANTES, CCL7/MCP-3, and CCL11/eotaxin. CCR3 is expressed on the surface of eosinophils, basophils, a subset of Th2 lymphocytes, mast cells, and airway epithelial cells. CCR3 and its ligands are involved in airway hyperresponsiveness in allergic asthma, ocular allergies, and cancers. Therefore, CCR3 is an attractive target for those therapies. Previously, anti-mouse CCR3 (mCCR3) monoclonal antibodies (mAbs), C₃Mab-3 (rat IgG_2a, kappa), and C₃Mab-4 (rat IgG_2a, kappa) were developed using the Cell-Based Immunization and Screening (CBIS) method. In this study, the binding epitope of these mAbs was investigated using flow cytometry. A CCR3 extracellular domain-substituted mutant analysis showed that C₃Mab-3, C₃Mab-4, and a commercially available mAb (J073E5) recognized the N-terminal region (amino acids 1-38) of mCCR3. Next, alanine scanning was conducted in the N-terminal region. The results revealed that the Ala2, Phe3, Asn4, and Thr5 of mCCR3 are involved in C₃Mab-3 binding, whereas Ala2, Phe3, and Thr5 are essential to C₃Mab-4 binding, and Ala2 and Phe3 are crucial to J073E5 binding. These results reveal the involvement of the N-terminus of mCCR3 in the recognition of C₃Mab-3, C₃Mab-4, and J073E5.

Aberrant regulation of CXCR4 in cancer via deviant microRNA-targeted interactions

CXCR4 is involved in many facets of cancer, including being a major player in establishing metastasis. This is in part due to the deregulation of CXCR4, which can be attributed to many genetic and epigenetic mechanisms, including aberrant microRNA-CXCR4 interaction. MicroRNAs (miRNAs) are a type of small non-coding RNA that primarily targets the 3' UTR of mRNA transcripts, which in turn suppresses mRNA and subsequent protein expression. In this review, we reported and characterized the many aberrant miRNA-CXCR4 interactions that occur throughout human cancers. In particular, we reported known target sequences located on the 3' UTR of CXCR4 transcripts that tumour suppressor miRNAs bind and therefore regulate expression by. From these aberrant interactions, we also documented affected downstream genes/pathways and whether a particular tumour suppressor miRNA was reported as a prognostic marker in its respected cancer type. In addition, a limited number of cancer-causing miRNAs coined 'oncomirs' were reported and described in relation to CXCR4 regulation. Moreover, the mechanisms underlying both tumour suppressor and oncomir deregulations concerning CXCR4 expression were also explored. Furthermore, the miR-146a-CXCR4 axis was delineated in oncoviral infected endothelial cells in the context of virus-causing cancers. Lastly, miRNA-driven therapies and CXCR4 antagonist drugs were discussed as potential future treatment options in reported cancers pertaining to deregulated miRNA-CXCR4 interactions.

Role of chemokines in HPV-induced cancers

Human papillomaviruses (HPVs) cause cancers of the uterine cervix, oropharynx, anus, and vulvovaginal tract. Low-risk HPVs, such as HPV6 and 11, can also cause benign mucosal lesions including genital warts, and in patients with recurrent respiratory papillomatosis, lesions in the larynx, and on occasion, in the lungs. However, both high and less tumorigenic HPVs share a striking commonality in manipulating both innate and adaptive immune responses in HPV- infected keratinocytes, the natural host for HPV infection. In addition, immune/inflammatory cell infiltration into the tumor microenvironment influences cancer growth and prognosis, and this process is tightly regulated by different chemokines. Chemokines are small proteins and exert their biological effects by binding with G protein-coupled chemokine receptors (GPCRs) that are found on the surfaces of select target cells. Chemokines are not only involved in the establishment of a pro-tumorigenic microenvironment and organ-directed metastases but also involved in disease progression through enhancing tumor cell growth and proliferation. Therefore, having a solid grasp on chemokines and immune checkpoint modulators can help in the treatment of these cancers. In this review, we discuss the recent advances on the expression patterns and regulation of the main chemokines found in HPV-induced cancers, and their effects on both immune and non-immune cells in these lesions. Importantly, we also present the current knowledge of therapeutic interventions on the expression of specific chemokine and their receptors that have been shown to influence the development and progression of HPV-induced cancers.

Analysis of CCR2 splice variant expression patterns and functional properties

Background

C–C motif chemokine receptor 2 (CCR2), the main receptor for monocyte chemoattractant protein-1 (MCP-1), is expressed on immune cells, including monocytes, macrophages, and activated T cells, and mediates cell migration toward MCP-1 in inflammation-related diseases. The CCR2 gene encodes two isoforms: CCR2A and CCR2B. The CCR2B open reading frame is localized in a single exon, similar to other chemokine receptors, and CCR2A and CCR2B feature different amino acid sequences in their C-terminal intracellular loops due to alternative splicing. Most biochemical studies on CCR2-related cellular responses in the immune system have focused on CCR2B, with few reports focused on CCR2A. Understanding the functional properties of CCR2A in cellular responses may elucidate the roles played by MCP-1 and CCR2 in pathophysiological responses.

Results

CCR2 gene expression analysis in several cell types revealed that most adherent cells only expressed CCR2A, whereas CCR2B expression was dominant in monocytic cells. The C-terminal Helix 8 region of CCR2A contains few basic amino acids, which may be unfavorable for cell surface localization, as confirmed with the HiBiT assay. CCR2B contains many C-terminal Ser/Thr residues, similar to other chemokine receptors, which may be phosphorylated by G protein–coupled receptor kinases (GRKs) to promote β-arrestin recruitment and subsequent endocytosis. By contrast, CCR2A contains few C-terminal Ser/Thr residues, which are unlikely to be phosphorylated by GRKs. CCR2A localized on the cell surface is resistant to internalization, despite the interaction between Gβ and GRKs induced by ligand binding with CCR2A. CCR2A induced cellular responses at a relatively higher degree than CCR2B, although both receptors mediated signaling events through Gαq and Gαi. HeLa cells lacking CCR2A showed slowed growth compared with parent cells, regardless of MCP-1 stimulation, and their chemotactic activity toward MCP-1, in addition to basal motility, was significantly impaired.

Conclusion

MCP-1 and CCR2 may play pivotal roles in cancer progression by recruiting macrophages into cancer tissue. This study demonstrates that CCR2A but not CCR2B is expressed in solid cancer–derived cells. CCR2A is resistant to internalization by β-arrestin due to a distinct C-terminal region from CCR2B, which enhances MCP-1-stimulated responses, indicating that CCR2A may play essential roles in solid cancer progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00787-6.

The immunological function of CXCR2 in the liver during sepsis

Background

The chemokine receptor CXCR2 and its ligands, especially CXCL8, are crucial mediators for the progression of liver inflammation and liver failure in sepsis. Neutrophils have the highest CXCR2 expression in mice and humans, and their activation via CXCL8 facilitates their migration to the inflamed liver for the clearance of the pathogens and, in turn, the inflammation.

Main body

In sepsis, the inflammatory insult causes extensive neutrophil migration to the liver that overwhelms the immune response. To compensate for the strong receptor activation, CXCR2 desensitizes, incapacitating the immune cells to efficiently clear pathogens, causing further life-threatening liver damage and uncontrolled pathogen spread.

Conclusion

CXCR2 function during infection strongly depends on the expressing cell type. It signals pro- and anti-inflammatory effects that may prompt novel cell-type-specific CXCR2-directed therapeutics.

Discovery of Chemokine CXCL12 Inhibitors by Tandem Application of Virtual Screening and NMR Spectrometry

The CXC chemokine ligand CXCL12 and its receptor CXCR4 play critical roles in stem-cell homing, infectious diseases, and cancer, which led the CXCL12/CXCR4 signaling axis to attract much attention in drug discovery. CXCR4 is regarded as the primary target while CXCL12 is considered too small to be a druggable target. In this paper, we employed virtual screening approaches and ligand-based NMR screening methods from a SPECS library and in-house natural products to discover new CXCR12 inhibitors. Four natural triterpene saponins were confirmed, and the triterpene sapogenin was identified as the main binding epitope by saturation transfer difference-nuclear magnetic resonance and molecular docking studies. The pentacyclic triterpene scaffold and its elucidated structure-activity relationships provide a new and valuable research direction for the development of novel CXCL12 inhibitors.

New Insights into Microglial Mechanisms of Memory Impairment in Alzheimer's Disease

Alzheimer's disease (AD) is the most common progressive and irreversible neurodegeneration characterized by the impairment of memory and cognition. Despite years of studies, no effective treatment and prevention strategies are available yet. Identifying new AD therapeutic targets is crucial for better elucidating the pathogenesis and establishing a valid treatment of AD. Growing evidence suggests that microglia play a critical role in AD. Microglia are resident macrophages in the central nervous system (CNS), and their core properties supporting main biological functions include surveillance, phagocytosis, and the release of soluble factors. Activated microglia not only directly mediate the central immune response, but also participate in the pathological changes of AD, including amyloid-beta (Aβ) aggregation, tau protein phosphorylation, synaptic dissection, neuron loss, memory function decline, etc. Based on these recent findings, we provide a new framework to summarize the role of microglia in AD memory impairment. This evidence suggests that microglia have the potential to become new targets for AD therapy.

Promising Advances in Pharmacotherapy for Patients with Spinal Cord Injury-A Review of Studies Performed In Vivo with Modern Drugs

Spinal cord injury (SCI) is a pathological neurological condition that leads to significant motor dysfunction. It is a condition that occurs as a result of tragic accidents, violent acts, or as a consequence of chronic diseases or degenerative changes. The current treatments for patients with SCI have moderate efficacy. They improve the quality of life of patients, but they are still doomed to long-term disability. In response to the modern directions of research on possible therapeutic methods that allow for the recovery of patients with SCI, a scientific review publication is needed to summarize the recent developments in this topic. The following review is focused on the available pharmacological treatments for SCIs and the problems that patients face depending on the location of the injury. In the following review, the research team describes problems related to spasticity and neuropathic pain; possible therapeutic pathways are also described for neuroprotection and the improvement of neurotransmission within the injured spinal cord, and the review focuses on issues related to oxidative stress.

Nerve decompression surgery suppresses TNF-ɑ expression and T cell infiltration in a rat sciatic nerve chronic constriction injury model

Decompression surgery (DS) is a standard treatment for chronic nerve compression injuries; however, the mechanisms underlying its effects remain unclear. Here, we investigated the effects of DS on messenger RNA (mRNA) expression of tumor necrosis factor-α (TNF-α) and T cell recruitment in a rat sciatic nerve (SN) chronic constriction injury (CCI) model. Male Wistar rats were subjected to CCI to establish a model of SN injury (CCI group). DS, in which all ligatures were removed, was performed 3 days after CCI surgery (CCI + dec group). Mechanical sensitivity was assessed using the von Frey test 3, 7, and 14 days after the CCI surgery. Gene expression of Tnfa, Cd3, Cxcl10, and immunolocalization of TNF-α and the pan T cell marker, CD3, was evaluated using quantitative polymerase chain reaction (qPCR) and immunohistochemistry, respectively. In addition, the effects of TNF-α on Cxcl10 expression and CXCL10 protein production were evaluated using qPCR and enzyme-linked immunosorbent assay in SN cell culture. Rats that received DS had significantly higher withdrawal threshold levels than those in the CCI group. In addition, Tnfa, Cd3, and Cxcl10 mRNA expression increased following CCI. DS suppressed this elevated expression, with the CCI + dec group showing significantly reduced expression levels compared to the CCI group. Furthermore, TNF-α induced Cxcl10 expression and CXCL10 protein production in SN cell culture. Therefore, DS reduced TNF-α expression and T cell recruitment in the rat SN CCI model. These observations may partly explain the mechanism underlying the therapeutic effects of DS.

Multifaceted role of chemokines in solid tumors: From biology to therapy

Chemokines are small secretory chemotactic cytokines that control the directed migration of immune cells. Chemokines are involved in both anti-and pro-tumorigenic immune responses. Accumulating evidence suggests that the balance between these responses is influenced by several factors such as the stage of tumorigenesis, immune cell activation, recruitment of immune activating or immunosuppressive cells in the tumor microenvironment (TME), and chemokine receptor expression on effector and regulatory target cells. Cancer cells engage in a complex network with their TME components via several factors including growth factors, cytokines and chemokines that are critical for the growth of primary tumor and metastasis. However, chemokines show a multifaceted role in tumor progression including maintenance of stem-like properties, tumor cell proliferation/survival/senescence, angiogenesis, and metastasis. The heterogeneity of solid tumors in primary and metastatic cancers presents a challenge to the development of successful cancer therapy. Despite extensive research on how solid tumors escape immune cell-mediated anti-tumor response, finding an effective therapy for metastatic cancer still remains a challenge. This review discusses the multifarious roles of chemokines in solid tumors including various chemokine signaling pathways such as CXCL8-CXCR1/2, CXCL9, 10, 11-CXCR3, CXCR4-CXCL12, CCL(X)-CCR(X) in primary and metastatic cancers. We further discuss the novel therapeutic approaches that have been developed by major breakthroughs in chemokine research to treat cancer patients by the strategic blockade/activation of these signaling axes alone or in combination with immunotherapies.

Inflammatory Chemokine Receptors Support Inflammatory Macrophage and Dendritic Cell Maturation

Dendritic cells form clusters in vivo, but the mechanism behind this has not been determined. In this article, we demonstrate that monocytes from mice deficient in the chemokine receptors CCR1, CCR2, CCR3, and CCR5 display reduced clustering in vitro, which is associated with impaired dendritic cell and macrophage differentiation. We further show that the differentiating cells themselves produce ligands for these receptors that function, in a redundant manner, to regulate cell clustering. Deletion of, or pharmacological blockade of, more than one of these receptors is required to impair clustering and differentiation. Our data show that chemokines and their receptors support clustering by increasing expression of, and activating, cell-surface integrins, which are associated with cell-cell interactions and, in the context of monocyte differentiation, with reduced expression of Foxp1, a known transcriptional suppressor of monocyte differentiation. Our data therefore provide a mechanism whereby chemokines and their receptors typically found in inflammatory environments can interact to promote murine monocyte differentiation to macrophages and dendritic cells.

Long noncoding RNA IRF1-AS is associated with peste des petits ruminants infection

Peste des petits ruminants (PPR) is an acute and highly contagious disease and has long been a significant threat to small ruminant productivity worldwide. However, the molecular mechanism underlying host-PPRV interactions remains unclear and the long noncoding RNAs (lncRNAs) regulation of PPR virus (PPRV) infection has rarely been reported so far. Here, we first demonstrated that PPRV infection can induce an obvious innate immune response in caprine endometrial epithelial cells (EECs) at 48 h post-infection (hpi) with an MOI of 3. Subsequently, we determined that PPRV infection is associated with 191 significantly differentially expressed (SDE) lncRNAs, namely, 137 upregulated and 54 downregulated lncRNAs, in caprine EECs compared with mock control cells at 48 hpi by using deep sequencing technology. Importantly, bioinformatics preliminarily analyses revealed that these DE lncRNAs were closely related to the immune response. Furthermore, we identified a system of lncRNAs related to the immune response and focused on the role of lncRNA 10636385 (IRF1-AS) in regulating the innate immune response. Interestingly, we found that IRF1-AS was a potent positive regulator of IFN-β and ISG production, which can significantly inhibit PPRV replication in host cells. In addition, our data revealed that IRF1-AS was positively correlated with its potential target gene, IRF1, which enhanced the activation of IRF3 and the expression of ISGs and interacted with IRF3. This study suggests that IRF1-AS could be a new host factor target for developing antiviral therapies against PPRV infection.