Inhibition of cc chemokine receptor 10 ameliorates osteoarthritis via inhibition of the phosphoinositide-3-kinase/Akt/mammalian target of rapamycin pathway.

BACKGROUND: Osteoarthritis (OA) is a joint disease characterized by inflammation and progressive cartilage degradation. Chondrocyte apoptosis is the most common pathological feature of OA. Interleukin-1ß (IL-1ß), a major inflammatory cytokine that promotes cartilage degradation in OA, often stimulates primary human chondrocytes in vitro to establish an in vitro OA model. Moreover, IL-1ß is involved in OA pathogenesis by stimulating the phosphoinositide-3-kinase (PI3K)/Akt and mitogen-activated protein kinases pathways. The G-protein-coupled receptor, cc chemokine receptor 10 (CCR10), plays a vital role in the occurrence and development of various malignant tumors. However, the mechanism underlying the role of CCR10 in the pathogenesis of OA remains unclear. We aimed to evaluate the protective effect of CCR10 on IL-1ß-stimulated CHON-001 cells and elucidate the underlying mechanism. METHODS: The CHON-001 cells were transfected with a control small interfering RNA (siRNA) or CCR10-siRNA for 24 h, and stimulated with 10 ng/mL IL-1ß for 12 h to construct an OA model in vitro. The levels of CCR10, cleaved-caspase-3, MMP-3, MMP-13, Collagen II, Aggrecan, p-PI3K, PI3K, p-Akt, Akt, phosphorylated-mammalian target of rapamycin (p-mTOR), and mTOR were detected using quantitative reverse transcription polymerase chain reaction and western blotting. Viability, cytotoxicity, and apoptosis of CHON-001 cells were assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, lactate dehydrogenase assay (LDH), and flow cytometry analysis, respectively. Inflammatory cytokines (TNF-α, IL-6, and IL-8) were assessed using enzyme-linked immunosorbent assay. RESULTS: Level of CCR10 was substantially higher in the IL-1ß-stimulated CHON-001 cells than that in the control group, whereas CCR10 was down-regulated in the CCR10-siRNA transfected CHON-001 cells compared to that in the control-siRNA group. Notably, CCR10 inhibition alleviated IL-1ß-induced inflammatory injury in the CHON-001 cells, as verified by enhanced cell viability, inhibited LDH release, reduced apoptotic cells, and cleaved-caspase-3 expression. Meanwhile, IL-1ß induced the release of tumor necrosis factor alpha, IL-6, and IL-8, increase of MMP-3 and MMP-13, and decrease of Collagen II and Aggrecan in the CHON-001 cells, which were reversed by CCR10-siRNA. However, these effects were reversed upon PI3K agonist 740Y-P treatment. Further, IL-1ß-induced PI3K/Akt/mTOR signaling pathway activation was inhibited by CCR10-siRNA, which was increased by 740Y-P treatment. CONCLUSION: Inhibition of CCR10 alleviates IL-1ß-induced chondrocytes injury via PI3K/Akt/mTOR pathway inhibition, suggesting that CCR10 might be a promising target for novel OA therapeutic strategies.

CCR10-mediated Enhancement of T Cell Trafficking for Improved Tumor Immunotherapy.

BACKGROUND/AIM: The effectiveness of adoptive T cell therapy for solid tumors remains suboptimal, partly attributed to insufficient T cell infiltration into the tumor site. A promising strategy involves directing T cells towards the tumor utilizing tumor-specific chemokine receptors. MATERIALS AND METHODS: We analyzed chemokine receptor expression in activated T cells and chemokine expression in breast and lung cancer using The Cancer Genome Atlas (TCGA) data. Subsequently, we generated 1G4 T cell receptor-engineered T (TCR-T) cells with CCR10 and performed in vitro and in vivo efficacy tests. RESULTS: CCR10 exhibited insufficient expression in various human T cells. Analysis of TCGA RNA sequencing data revealed elevated expression of the chemokine CCL28, the corresponding chemokine for CCR10, in breast and lung cancer. Consequently, we generated CCR10-1G4 TCR-T cells. CCR10-1G4 dual expressing TCR-T cells exhibited comparable cellular cytotoxicity but increased mobility compared to 1G4 TCR-T cells in vitro. Furthermore, injecting CCR10-1G4 dual expressing TCR-T cells into a xenograft tumor model demonstrated enhanced in vivo trafficking and a greater reduction of tumor burden. CONCLUSION: This study highlights the potential of CCR10 for developing efficient adoptive T-cell treatments targeting solid tumors.

Mucosal CCL28 Chemokine Improves Protection against Genital Herpes through Mobilization of Antiviral Effector Memory CCR10+CD44+ CD62L-CD8+ T Cells and Memory CCR10+B220+CD27+ B Cells into the Infected Vaginal Mucosa.

Four major mucosal-associated chemokines, CCL25, CCL28, CXCL14, and CXCL17, play an important role in protecting mucosal surfaces from infectious pathogens. However, their role in protection against genital herpes remains to be fully explored. The CCL28 is a chemoattractant for the CCR10 receptor-expressing immune cells and is produced homeostatically in the human vaginal mucosa (VM). In this study, we investigated the role of the CCL28/CCR10 chemokine axis in mobilizing protective antiviral B and T cell subsets into the VM site of herpes infection. We report a significant increase in the frequencies of HSV-specific memory CCR10+CD44+CD8+ T cells, expressing high levels of CCR10, in herpes-infected asymptomatic (ASYMP) women compared with symptomatic women. Similarly, a significant increase in the CCL28 chemokine (a ligand of CCR10), was detected in the VM of herpes-infected ASYMP C57BL/6 mice, associated with the mobilization of high frequencies of HSV-specific effector memory CCR10+CD44+CD62L-CD8+ TEM cells and memory CCR10+B220+CD27+ B cells in the VM of HSV-infected ASYMP mice. Inversely, compared with wild-type C57BL/6 mice, the CCL28 knockout (CCL28-/-) mice (1) appeared to be more susceptible to intravaginal infection and reinfection with HSV type 2, and (2) exhibited a significant decrease in the frequencies of HSV-specific effector memory CCR10+CD44+CD62L-CD8+ TEM cells and of memory CD27+B220+ B cells in the infected VM. These findings suggest a critical role of the CCL28/CCR10 chemokine axis in the mobilization of antiviral memory B and T cells within the VM to protect against genital herpes infection and disease.

Blocking CCR10 Expression Activates m6A Methylation and Alleviates Vascular Endothelial Cell Injury.

BACKGROUND: Cardiovascular disease, one of the most common types of disease in clinical practice today, carries a very high risk of disability and death. This research aims to examine genome-wide changes in injured human dermal microvascular endothelial cells (HDMECs) using the Ribonucleic Acid sequencing (RNA-Seq) technique, and to search for key genes influencing N6-methyladenosine (m6A) methylation, thus gaining new insights into future clinical diagnosis and treatment of cardiovascular diseases (CVDs) and laying a foundation for follow-up research. METHODS: Impaired HDMECs (injury group), established by endotoxin intervention, were analyzed by RNA-Seq for differentially expressed genes (DEGs) relative to normal HDMECs (control group). Then, DEGs that might be associated with m6A methylation were selected for expression blocking to observe m6A methylation alterations. The migration, angiogenesis, and inflammatory response of damaged HDMECs were detected by cell scratch assay, western blotting, and Enzyme-linked Immunosorbent Assay (ELISA) experiments, respectively. RESULTS: In this study, 20 DEGs were screened out from the two groups by RNA-Seq, of which 17 were up-regulated and 3 were down-regulated. The C-C motif chemokine receptor 10 (CCR10) was selected for subsequent analysis. Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR) identified elevated CCR10 expression and reduced m6A methylation levels in the injury group (p < 0.05). After blocking CCR10 expression in damaged HDMECs by BI6901 (a CCR10 specific blocker) m6A methylation, cell activity, vascular endothelial growth factor A (VEGFA) and CD31 protein expression, as well as relative length and branches of tube formation were found to be increased compared with the injury group, while the levels of inflammatory factors interleukin-1 (IL-1), interleukin-1 (IL-6) and tumor necrosis factor-α (TNF-α) were decreased (p < 0.05). CONCLUSIONS: Blocking CCR10 expression can activate m6A methylation, promote cell activity, inhibit inflammatory reactions and alleviate HDMEC injury, which may become a breakthrough in future diagnosis and treatment of cardiovascular diseases.

The CCL27-CCR10 axis contributes to promoting proliferation, migration, and invasion of lung squamous cell carcinoma.

Lung cancer is characterized by its high mortality and morbidity. A deep understanding of the molecular mechanisms of lung cancer tumorigenesis helps to develop novel lung cancer diagnostic and therapeutic strategies. However, the picture of the associated molecular landscape is not yet complete. As understood, chemokine-receptor interactions contribute much to lung cancer tumorigenesis, in which CCR10 also plays an important role. This study aimed to expand the knowledge of CCR10 in lung squamous cell carcinoma (LUSC) in the manner of molecular mechanism and biological functions. Using GEPIA database, the survival analysis between LUSC patients with high and low CCR10 expressions was performed, showing that CCR10 could be regarded as a risk factor for LUSC patients. Subsequently, CCR10 protein and mRNA expressions in LUSC were examined by qRT-PCR and western blot respectively. The results indicated that CCR10 was highly expressed in LUSC cells. The results of CCK-8, colony formation, and Transwell assays presented that CCL27, the ligand of CCR10, promoted proliferative, migratory, and invasive abilities of LUSC cells by activating CCR10. Also, the PI3K/AKT signaling pathway was verified as the involved pathway by western blot. Overall, it could be concluded that the CCL27-CCR10 regulatory axis can activate the PI3K/AKT pathway fostering the malignant features of LUSC cells.

[Role of the CCL28-CCR10 pathway in monocyte migration in rheumatoid arthritis].

OBJECTIVE: To examine the expression of chemokine receptor CCR10 on monocytes/macrophages in the joints of patients with rheumatoid arthritis (RA), and to investigate the role of chemokine CCL28 and its receptor CCR10 in the migration of RA monocytes and its mechanism. METHODS: The expression of CCR10 in synovial tissues from 8 RA patients, 4 osteoarthritis (OA) patients, and 4 normal controls was analyzed by immunohistochemistry, and cell staining was scored on a 0-5 scales. Flow cytometry was used to measure the percentage of CCR10 positive cells in CD14+ monocytes from peripheral blood of 26 RA patients and 20 healthy controls, as well as from synovial fluid of 15 RA patients. The chemotactic migration of monocytes from RA patients and healthy controls in response to CCL28 was evaluated using an in vitro Transwell system. Western blotting was conducted to assess phosphorylation of the extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) pathways in RA monocytes upon CCL28 treatment. RESULTS: CCR10 was predominantly expressed in RA synovial lining cells and sublining macrophages, endothelial cells, and lymphocytes. CCR10 expression was significantly increased on lining cells and sublining macrophages in RA synovial tissue compared with OA and normal synovial tissue (both P < 0.01). The patients with RA had markedly elevated expression of CCR10 on peripheral blood CD14+ monocytes compared with the healthy controls [(15.6±3.0)% vs. (7.7±3.8)%, P < 0.01]. CCR10 expression on synovial fluid monocytes from the RA patients was (32.0±15.0)%, which was significantly higher than that on RA peripheral blood monocytes (P < 0.01). In vitro, CCL28 caused significant migration of CD14+ monocytes from peripheral blood of the RA patients and the healthy controls at concentrations ranging from 10-100 µg/L (all P < 0.01). The presence of neutralizing antibody to CCR10 greatly suppressed CCL28-driven chemotaxis of RA monocytes (P < 0.01). Stimulation of RA monocytes with CCL28 induced a remarkable increase in phosphorylation of ERK and Akt (both P < 0.05). ERK inhibitor (U0126) and phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) strongly reduced the migration of RA monocytes in response to CCL28 (both P < 0.01). CONCLUSION: RA patients had increased CCR10 expression on peripheral blood, synovial fluid, and synovial tissue monocytes/macrophages. CCL28 ligation to CCR10 promoted RA monocyte migration through activation of the ERK and PI3K/Akt signaling pathways. The CCL28-CCR10 pathway could participate in monocyte recruitment into RA joints, thereby contributing to synovial inflammation and bone destruction.

Roles of CCR10/CCL27-CCL28 axis in tumour development: mechanisms, diagnostic and therapeutic approaches, and perspectives.

Cancer is now one of the major causes of death across the globe. The imbalance of cytokine and chemokine secretion has been reported to be involved in cancer development. Meanwhile, CC chemokines have received considerable interest in cancer research. CCR10, as the latest identified CC chemokine receptor (CCR), has been implicated in the recruitment and infiltration of immune cells, especially lymphocytes, into epithelia such as skin via ligation to two ligands, CCL27 and CCL28. Other than homoeostatic function, several mechanisms have been shown to dysregulate CCR10/CCL27-CCL28 expression in the tumour microenvironment. As such, these receptors and ligands mediate T-cell trafficking in the tumour microenvironment. Depending on the types of lymphocytes recruited, CCR10/CCL27-CCL28 interaction has been shown to play conflicting roles in cancer development. If they were T helper and cytotoxic T cells and natural killer cells, the role of this axis would be tumour-suppressive. In contrast, if CCR10/CCL27-CCL28 recruited regulatory T cells, cancer-associated fibroblasts or myeloid-derived suppressor cells, it would lead to tumour progression. In addition to the trafficking of lymphocytes and immune cells, CCR10 also leads to the migration of tumour cells or endothelial cells (called angiogenesis and lymphangiogenesis) to promote tumour metastasis. Furthermore, CCR10 signalling triggers tumour-promoting signalling such as PI3K/AKT and mitogen-activated protein kinase/extracellular signal-regulated kinase, resulting in tumour cell growth. Since CCR10/CCL27-CCL28 is dysregulated in the tumour tissues, it is suggested that analysis and measurement of them might predict tumour development. Finally, it is hoped using therapeutic approaches based on this axis might increase our knowledge to overcome tumour progression.

Inhibition of CCL28/CCR10-Mediated eNOS Downregulation Improves Skin Wound Healing in the Obesity-Induced Mouse Model of Type 2 Diabetes.

Chronic, nonhealing skin wounds, such as diabetic foot ulcers (DFUs), are common in patients with type 2 diabetes. Here, we investigated the role of chemokine (C-C motif) ligand 28 (CCL28) and its receptor C-C chemokine receptor type 10 (CCR10) in downregulation of endothelial nitric (NO) oxide synthase (eNOS) in association with delayed skin wound healing in the db/db mouse model of type 2 diabetes. We observed reduced eNOS expression and elevated CCL28/CCR10 levels in dorsal skin of db/db mice and subdermal leg biopsy specimens from human subjects with type 2 diabetes. Further interrogation revealed that overexpression of CCR10 reduced eNOS expression, NO bioavailability, and tube formation of human dermal microvascular endothelial cells (HDMVECs) in vitro, which was recapitulated in mouse dorsal skin. In addition, incubation of HDMVECs with CCL28 led to internalization of the CCR10/eNOS complex and colocalization with lysosome-associated membrane protein 1. Finally, topical application of myristoylated CCR10 binding domain 7 amino acid (Myr-CBD7) peptide prevented CCR10-eNOS interaction and subsequent eNOS downregulation, enhanced eNOS/NO levels, eNOS/VEGF-R2+ microvessel density, and blood perfusion, reduced inflammatory cytokine levels, and importantly, decreased wound healing time in db/db mice. Thus, endothelial cell CCR10 activation in genetically obese mice with type 2 diabetes promotes eNOS depletion and endothelial dysfunction, and targeted disruption of CCR10/eNOS interaction improves wound healing.

The Role of Atypical Chemokine Receptor D6 (ACKR2) in Physiological and Pathological Conditions; Friend, Foe, or Both?

Chemokines exert crucial roles in inducing immune responses through ligation to their canonical receptors. Besides these receptors, there are other atypical chemokine receptors (ACKR1-4) that can bind to a wide range of chemokines and carry out various functions in the body. ACKR2, due to its ability to bind various CC chemokines, has attracted much attention during the past few years. ACKR2 has been shown to be expressed in different cells, including trophoblasts, myeloid cells, and especially lymphoid endothelial cells. In terms of molecular functions, ACKR2 scavenges various inflammatory chemokines and affects inflammatory microenvironments. In the period of pregnancy and fetal development, ACKR2 plays a pivotal role in maintaining the fetus from inflammatory reactions and inhibiting subsequent abortion. In adults, ACKR2 is thought to be a resolving agent in the body because it scavenges chemokines. This leads to the alleviation of inflammation in different situations, including cardiovascular diseases, autoimmune diseases, neurological disorders, and infections. In cancer, ACKR2 exerts conflicting roles, either tumor-promoting or tumor-suppressing. On the one hand, ACKR2 inhibits the recruitment of tumor-promoting cells and suppresses tumor-promoting inflammation to blockade inflammatory responses that are favorable for tumor growth. In contrast, scavenging chemokines in the tumor microenvironment might lead to disruption in NK cell recruitment to the tumor microenvironment. Other than its involvement in diseases, analyzing the expression of ACKR2 in body fluids and tissues can be used as a biomarker for diseases. In conclusion, this review study has tried to shed more light on the various effects of ACKR2 on different inflammatory conditions.

Interleukin-17 Receptor E and C-C Motif Chemokine Receptor 10 Identify Heterogeneous T Helper 17 Subsets in a Mouse Dry Eye Disease Model.

Dry eye disease (DED) features the inflammatory response of the ocular surface. Pro-inflammatory T helper 17 (Th17) cells are important for the pathogenesis of DED. In the present study a mouse DED model was used to discover two Th17 subsets in draining lymph nodes and conjunctivae based on the expression of IL-17 receptor E (IL-17RE) and CCR10: IL-17RElowCCR10- Th17 and IL-17REhighCCR10+ Th17. IL-17REhighCCR10+ Th17 expressed more retinoic acid-related orphan receptor gamma t but fewer T-box-expressed-in-T-cells than IL-17RElowCCR10- Th17. In addition, the former expressed higher IL-17A, IL-21, and IL-22 but fewer IFN-γ than the latter. Further analysis showed that IL-17REhighCCR10+ Th17 did not express IFN-γ in vivo, whereas IL-17RElowCCR10- Th17 contained IFN-γ-expressing Th17/Th1 cells. Moreover, IL-17REhighCCR10+ Th17 possessed more phosphorylated p38 mitogen-activated protein kinase (MAPK) and Jnk than IL-17RElowCCR10- Th17, suggesting higher activation of MAPK signaling in IL-17REhighCCR10+ Th17. In vitro treatment with IL-17C effectively maintained IL-17A expression in Th17 cells through p38 MAPK rather than Jnk MAPK. Furthermore, the adoptive transfer of the two Th17 subpopulations indicated their equivalent pathogenicity in DED. Interestingly, IL-17REhighCCR10+ Th17 cells were able to phenotypically polarize to IL-17RElowCCR10- Th17 cells in vivo. In conclusion, the current study revealed novel Th17 subsets with differential phenotypes, functions, and signaling status in DED, thus deepening the understanding of Th17 pathogenicity, and exhibited Th17 heterogeneity in DED.

Knockdown of CCL28 inhibits endometriosis stromal cell proliferation and invasion via ERK signaling pathway inactivation.

Endometriosis (EM), the presence of functional endometrial glands and stroma outside the uterine cavity, is a common gynecological disorder. At present, the pathogenesis of EM has not been fully elucidated, so there is still a lack of effective therapy. The present study aimed to explore the role of C­C motif chemokine ligand 28 (CCL28) and its underlying mechanism in endometrial stromal cells to propose a novel therapy for EM treatment. The expression of CCL28 and CC chemokine receptor 10 (CCR10) were examined. After CCL28 knockdown or overexpression by lentivirus infection, cell proliferation and invasion were measured. It was revealed that compared with normal, the expression levels of CCL28 and CCR10 were significantly elevated in endometrial tissues of patients with EM. Knockdown of CCL28 in endometrial stromal cells significantly suppressed cell proliferation and invasion, and this was accompanied by significantly reduced expression levels of CCR10, MMP2, MMP9, integrin ß1 (ITGB1) and phosphorylated (p)­ERK/ERK ratio. The addition of the CCL28 recombinant protein had an opposite effect to CCL28 downregulation. Furthermore, the ERK inhibitor, PD98059, reduced CCL28­induced cell proliferation and invasion, as well as the expression levels of MMP2, MMP9, ITGB1 and p­ERK. Therefore, the present study indicated that CCL28 may contribute to the progression of EM by regulating MMP2, MMP9 and ITGB1 expression and function via the activation of the ERK signaling pathway.

SARS-CoV2 pneumonia recovery is linked to expansion of innate lymphoid cells type 2 expressing CCR10.

Accelerate lung repair in SARS-CoV-2 pneumonia is essential for pandemic handling. Innate lymphoid cells (ILCs) are likely players, given their role in mucosal protection and tissue homeostasis. We studied ILC subpopulations at two time points in a cohort of patients admitted in the hospital due to SARS-CoV-2 infection. COVID-19 patients with moderate/severe respiratory failure featured profound depletion of circulating ILCs at hospital admission, in agreement with overall lymphocyte depletion. However, ILCs recovered in direct correlation with lung function improvement as measured by oxygenation index and in negative association with inflammatory and lung/endothelial damage markers like RAGE. While both ILC1 and ILC2 expanded, ILC2 showed the most striking phenotype changes, with CCR10 upregulation in strong correlation with these parameters. Overall, CCR10+ ILC2 emerge as relevant contributors to SARS-CoV-2 pneumonia recovery.

Single-cell transcriptomics applied to emigrating cells from psoriasis elucidate pathogenic versus regulatory immune cell subsets.

BACKGROUND: In previous human skin single-cell data, inflammatory cells constituted only a small fraction of the overall cell population, such that functional subsets were difficult to ascertain. OBJECTIVE: Our aims were to overcome the aforesaid limitation by applying single-cell transcriptomics to emigrating cells from skin and elucidate ex vivo gene expression profiles of pathogenic versus regulatory immune cell subsets in the skin of individuals with psoriasis. METHODS: We harvested emigrating cells from human psoriasis skin after incubation in culture medium without enzyme digestion or cell sorting and analyzed cells with single-cell RNA sequencing and flow cytometry simultaneously. RESULTS: Unsupervised clustering of harvested cells from psoriasis skin and control skin identified natural killer cells, T-cell subsets, dendritic cell subsets, melanocytes, and keratinocytes in different layers. Comparison between psoriasis cells and control cells within each cluster revealed that (1) cutaneous type 17 T cells display highly differing transcriptome profiles depending on IL-17A versus IL-17F expression and IFN-γ versus IL-10 expression; (2) semimature dendritic cells are regulatory dendritic cells with high IL-10 expression, but a subset of semimature dendritic cells expresses IL-23A and IL-36G in psoriasis; and (3) CCL27-CCR10 interaction is potentially impaired in psoriasis because of decreased CCL27 expression in basal keratinocytes. CONCLUSION: We propose that single-cell transcriptomics applied to emigrating cells from human skin provides an innovative study platform to compare gene expression profiles of heterogenous immune cells in various inflammatory skin diseases.

Antibody-mediated depletion of CCR10+EphA3+ cells ameliorates fibrosis in IPF.

Idiopathic pulmonary fibrosis (IPF) is characterized by aberrant repair that diminishes lung function via mechanisms that remain poorly understood. CC chemokine receptor (CCR10) and its ligand CCL28 were both elevated in IPF compared with normal donors. CCR10 was highly expressed by various cells from IPF lungs, most notably stage-specific embryonic antigen-4-positive mesenchymal progenitor cells (MPCs). In vitro, CCL28 promoted the proliferation of CCR10+ MPCs while CRISPR/Cas9-mediated targeting of CCR10 resulted in the death of MPCs. Following the intravenous injection of various cells from IPF lungs into immunodeficient (NOD/SCID-γ, NSG) mice, human CCR10+ cells initiated and maintained fibrosis in NSG mice. Eph receptor A3 (EphA3) was among the highest expressed receptor tyrosine kinases detected on IPF CCR10+ cells. Ifabotuzumab-targeted killing of EphA3+ cells significantly reduced the numbers of CCR10+ cells and ameliorated pulmonary fibrosis in humanized NSG mice. Thus, human CCR10+ cells promote pulmonary fibrosis, and EphA3 mAb-directed elimination of these cells inhibits lung fibrosis.

Systematic Assessment of Chemokine Signaling at Chemokine Receptors CCR4, CCR7 and CCR10.

Chemokines interact with chemokine receptors in a promiscuous network, such that each receptor can be activated by multiple chemokines. Moreover, different chemokines have been reported to preferentially activate different signalling pathways via the same receptor, a phenomenon known as biased agonism. The human CC chemokine receptors (CCRs) CCR4, CCR7 and CCR10 play important roles in T cell trafficking and have been reported to display biased agonism. To systematically characterize these effects, we analysed G protein- and ß-arrestin-mediated signal transduction resulting from stimulation of these receptors by each of their cognate chemokine ligands within the same cellular background. Although the chemokines did not elicit ligand-biased agonism, the three receptors exhibited different arrays of signaling outcomes. Stimulation of CCR4 by either CC chemokine ligand 17 (CCL17) or CCL22 induced ß-arrestin recruitment but not G protein-mediated signaling, suggesting that CCR4 has the potential to act as a scavenger receptor. At CCR7, both CCL19 and CCL21 stimulated G protein signaling and ß-arrestin recruitment, with CCL19 consistently displaying higher potency. At CCR10, CCL27 and CCL28(4-108) stimulated both G protein signaling and ß-arrestin recruitment, whereas CCL28(1-108) was inactive, suggesting that CCL28(4-108) is the biologically relevant form of this chemokine. These comparisons emphasize the intrinsic abilities of different receptors to couple with different downstream signaling pathways. Comparison of these results with previous studies indicates that differential agonism at these receptors may be highly dependent on the cellular context.

Plasmodium infection prevents recurrence and metastasis of hepatocellular carcinoma possibly via inhibition of the epithelial­mesenchymal transition.

Postoperative recurrence causes a high mortality rate among patients with hepatocellular carcinoma (HCC). The current study aimed to determine the effects of Plasmodium infection on HCC metastasis and recurrence. The antitumor effects of Plasmodium infection were determined using two murine orthotopic HCC models: The non­resection model and the resection model. Tumour tissues derived from tumour­bearing mice treated with or without Plasmodium infection were harvested 15 days post­tumour inoculation. The expression levels of biomarkers related to epithelial­mesenchymal transition (EMT) and molecules associated with CC­chemokine receptor 10 (CCR10)­mediated PI3K/Akt/GSK­3ß/Snail signalling were identified using reverse transcription­quantitative PCR and western blotting. The results demonstrated that Plasmodium infection significantly suppressed the progression, recurrence and metastasis of HCC in the two mouse models. The expression levels of E­cadherin were significantly higher in the Plasmodium­treated group compared with that in the control group, whereas the expression levels of Vimentin and Snail were significantly lower in the Plasmodium­treated group. Furthermore, Plasmodium infection inhibited the activation of Akt and GSK­3ß in the tumour tissues by downregulating the expression levels of CCR10 and subsequently suppressing the accumulation of Snail, which may contribute to the suppression of EMT and the prevention of tumour recurrence and metastasis. In conclusion, the results of the present study demonstrated that Plasmodium infection inhibited the recurrence and metastasis and improved the prognosis of HCC by suppressing CCR10­mediated PI3K/Akt/GSK­3ß/Snail signalling and preventing the EMT. These results may be important for the development of novel therapies for HCC recurrence and metastasis, especially for patients in the perioperative period.

Tissue-Resident Memory CD8+ T Cells From Skin Differentiate Psoriatic Arthritis From Psoriasis.

OBJECTIVE: To compare immune cell phenotype and function in psoriatic arthritis (PsA) versus psoriasis in order to better understand the pathogenesis of PsA. METHODS: In-depth immunophenotyping of different T cell and dendritic cell subsets was performed in patients with PsA, psoriasis, or axial spondyloarthritis and healthy controls. Subsequently, we analyzed cells from peripheral blood, synovial fluid (SF), and skin biopsy specimens using flow cytometry, along with high-throughput transcriptome analyses and functional assays on the specific cell populations that appeared to differentiate PsA from psoriasis. RESULTS: Compared to healthy controls, the peripheral blood of patients with PsA was characterized by an increase in regulatory CD4+ T cells and interleukin-17A (IL-17A) and IL-22 coproducing CD8+ T cells. One population specifically differentiated PsA from psoriasis: i.e., CD8+CCR10+ T cells were enriched in PsA. CD8+CCR10+ T cells expressed high levels of DNAX accessory molecule 1 and were effector memory cells that coexpressed skin-homing receptors CCR4 and cutaneous lymphocyte antigen. CD8+CCR10+ T cells were detected under inflammatory and homeostatic conditions in skin, but were not enriched in SF. Gene profiling further revealed that CD8+CCR10+ T cells expressed GATA3, FOXP3, and core transcriptional signature of tissue-resident memory T cells, including CD103. Specific genes, including RORC, IFNAR1, and ERAP1, were up-regulated in PsA compared to psoriasis. CD8+CCR10+ T cells were endowed with a Tc2/22-like cytokine profile, lacked cytotoxic potential, and displayed overall regulatory function. CONCLUSION: Tissue-resident memory CD8+ T cells derived from the skin are enhanced in the circulation of patients with PsA compared to patients with psoriasis alone. This may indicate that aberrances in cutaneous tissue homeostasis contribute to arthritis development.

Coordinated co-migration of CCR10+ antibody-producing B cells with helper T cells for colonic homeostatic regulation.

In the intestine, IgA antibody-secreting B cells (IgA-ASCs) and helper T cells coordinate to maintain local homeostasis while their dysregulation could lead to development of intestinal inflammatory diseases. However, mechanisms underlying the coordinated localization and function of the B and T cells into the intestine, particularly the colon, are poorly understood. We herein report the first evidence that the gut-homing chemokine receptor CCR10+ IgA-ASCs form conjugates with helper T cells, preferentially regulatory T cells, at their differentiation sites of gut-associated lymphoid organs for their coordinated co-localization into the colon to promote local homeostasis. In CCR10-knockout mice, defective migration of IgA-ASCs also resulted in defective T-cell migration and homeostasis, and development of inflammatory symptoms in the colon. Antigen-specific interaction of CCR10+ IgA-ASCs and T cells is crucial for their homeostatic establishment in the colon. On the other hand, in IgA-knockout mice, preferential expansion of CCR10+ IgG1-ASCs with regulatory functions compensated for CCR10+ IgA-ASCs to help maintain colonic homeostasis. The preferential expansion of specific subclasses of CCR10+ IgG-ASCs with regulatory functions was also found in asymptomatic IgA-deficient patients. These findings suggest coordinated cell migration as a novel mechanism underlying localization and function of B and T cells in colonic homeostatic regulation.

Innate lymphoid cells regulate radiation-induced skin damage via CCR10 signaling.

OBJECTIVE: To assess the role of CCR10 in innate lymphoid cells (ILCs) response in radiation-induced skin damage. MATERIAL AND METHODS: CCR10+/- and CCR10-/- mice were treated with either a single dose of 5 Gy or 5 Gy everyday for 6 days with a total dose of 30 Gy with X-ray. ILCs from the skin were isolated and analyzed by flow cytometry 3 and 10 days after irradiation. A mouse model of radio-dermatitis was used to assess the skin damage 10 days after 6 × 5 Gy irradiation. RESULTS: Skin ILCs were decreased in both CCR10+/- and CCR10-/- mice 3 days after single irradiation (p < .05). However, the skin inflammation disappeared and ILCs returned to normal levels 10 days after single irradiation. ILCs of both genotypes were also decreased after 6 × 5 Gy irradiation, but the percentage of skin ILCs in CCR10-/- mice was lower than that in CCR10+/- mice 10 days after irradiation. The immunohistochemistry results showed that CCR10-/- mice had more severe skin inflammation than CCR10+/- mice. CONCLUSION: CCR10-/- mice had lower percentages of ILCs and more skin damage than CCR10+/- mice after irradiation. These findings indicate that skin ILCs are regulated by CCR10, which might be a potential target for reducing the radio-dermatitis.