Chemokine Receptors CCR1, CCR3, CCR7 and Chemokines CX3CL1 and CCL5 are Significantly Up-Regulated and Very Reliable for Acute Rejection Diagnosis of Kidney Transplants

Background: The allo-immune response following organ transplantation constitutes one of the main determinants concerning both short- and long- term outcomes in renal graft recipients. Chemokines and their receptors play a diversified and important role, either homeostatic or inflammatory and direct different immune-competent cell types to the allograft. While deeply studied in the last two decades, controversy persists as a result of chemokines’ pleiotropic actions. We report our analysis of CCR1, CCR3, CCR7, CCL5 and CX3CL1 expression or synthesis by graft-infiltrating cells in human kidney transplants (KTx). At the same time, we tested their robustness in diagnosing acute rejection. Methods: Fine-needle aspiration biopsies (Fnab) were performed either on days 7 or 14 post-transplantation among stable KTx and on the day of acute rejection (AR) diagnosis. Fnab cytopreparations were studied by the enzymatic avidin-biotin complex staining for CCR1, CCR3, CCR7 and CX3CL1. From another subgroup of cases, Fnab samples were cultured for 48 hours and the supernatants were analysed for CCL5 by ELISA. Results: The group of AR cases showed a significantly up-regulated expression of CCR1, CCR3, CCR7 and CX3CL1 and a significantly higher synthesis of CCL5. The positive predictive values were respectively 92%, 97%, 85%, 76% and 78% and negative predictive values were by the same order, 100%, 73%, 100%, 98% and 83%. Conclusions: Our study permits us to advance that CCR1 and CCR3 play a significant and non-redundant role in acute rejection, and it is the first report of CCR3 association with rejection, probably related to CCL5. The presence inside the graft of significant up-regulation for CCR7 surmises that part of antigen presentation may be performed there without being restricted to secondary lymphoid sites. Our results with CX3CL1 confirm other reports.

mRNA Expression of Chemokine Receptors on Peripheral Blood Mononuclear Cells and Correlation with Clinical Features in Systemic Lupus Erythematosus Patients

Objective To investigate the expressions of chemokine receptors and interleukin （IL） receptors on the peripheral blood mononuclear cells （PBMCs） from systemic lupus erythematosus （SLE） patients and their correlations with clinical features as well as SLE disease activity index （SLEDAI）. Methods The mRNA expressions of chemokine receptors and IL receptors on PBMCs of 93 SLE patients and 30 healthy controls were detected by reverse transcription-polymerase chain reaction, including CCR2, CCR3, CCR4, CCR5, CCR6, CCR8, CXCR3, CXCR5, CX3CR1, XCR1, IL-4R, and IL-10R. The clinical features of SLE patients were recorded. The correlations of chemokine receptors and IL receptors mRNA expressions with clinical features as well as SLEDAI were assayed using linear regression analysis. Results The level of CCR5 mRNA in SLE patients （including active and inactive SLE） was signifi- cantly higher than that in healthy controls （P〈0.05）, and there was no significant difference between active and inactive patients in this respect （P〉0.05）. CX3CR1 mRNA expression significantly increased from healthy control to inactive SLE to active SLE in sequence. The others （except for CCR8, CXCR3, and IL-1 OR） in active SLE patients weresignificantly higher than those in both inactive SLE patients and healthy controls （all P〈0.05）. There were positive correlations between SLEDAI and CCR2 （r=0.424, t=4.313, P〈0.001）, CCR3 （r=0.518, t=5.410, P〈0.001）, CCR4 （r=0.376, t=3.851, P〈0.001）, CCR6 （r=0.457, t=4.513,P〈0.001）, CXCR5 （r=0.455, t=4.629, P〈0.001）, CX3CR1 （r=0.44-5, t=4.523, P〈0.001）, as well as XCRI （r=0.540, t=5.445, P〈0.001）. And CCR5 mRNA expression level was positively correlated with IL-4R mRNA （r=0.313, t=2.353, P〈0.05）. The patients with myositis and cutaneous vasculitis simultaneously showed lower levels of CCR5 and CX3CRI, and CCR5 expression was negatively correlated with the scores of SLEDAI in SLE cases accompanied by photosensitivity （r=0.426, t=- 2.155, P〈0.05）. Conclusion Increased expressions of CCR5 and CX3CRI on PBMCs may be indicators in clinical survey for SLE.

CXC chemokines and chemokine receptors in gastric cancer: From basic findings towards therapeutic targeting

Gastric cancer is the fourth most common cancer,and the second-highest cause of cancer-related deaths worldwide.Despite extensive research to identify novel diagnostic and therapeutic agents,patients with advanced gastric cancer suffer from a poor quality of life and poor prognosis,and treatment is dependent mainly on conventional cytotoxic chemotherapy.To improve the quality of life and survival of gastric cancer patients,a better understanding of the underlying molecular pathologies,and their application towards the development of novel targeted therapies,is urgently needed.Chemokines are a group of small proteins associated with cytoskeletal rearrangements,the directional migration of several cell types during development and physiology,and the host immune response via interactions with G-protein coupled receptors.There is also growing evidence to suggest that chemokines not only play a role in the immune system,but are also involved in the development and progression of tumors.In gastric cancer,CXC chemokines and chemokine receptors regulate the trafficking of cells in and out of the tumor microenvironment.CXC chemokines and their receptors can also directly influence tumorigenesis by modulating tumor transformation,survival,growth,invasion and metastasis,as well as indirectly by regulating angiogenesis,and tumor-leukocyte interactions.In this review,we will focus on the roles of CXC chemokines and their receptors in the development,progression,and metastasis of gastric tumors,and discuss their therapeutic potential for gastric cancer.

C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 pathway as a therapeutic target and regulatory mechanism for spinal cord injury

Spinal cord injury involves non-reversible damage to the central nervous system that is characterized by limited regenerative capacity and secondary inflammatory damage.The expression of the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis exhibits significant differences before and after injury.Recent studies have revealed that the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis is closely associated with secondary inflammatory responses and the recruitment of immune cells following spinal cord injury,suggesting that this axis is a novel target and regulatory control point for treatment.This review comprehensively examines the therapeutic strategies targeting the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis,along with the regenerative and repair mechanisms linking the axis to spinal cord injury.Additionally,we summarize the upstream and downstream inflammatory signaling pathways associated with spinal cord injury and the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review primarily elaborates on therapeutic strategies that target the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the latest progress of research on antagonistic drugs,along with the approaches used to exploit new therapeutic targets within the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the development of targeted drugs.Nevertheless,there are presently no clinical studies relating to spinal cord injury that are focusing on the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review aims to provide new ideas and therapeutic strategies for the future treatment of spinal cord injury.

Role of chemokines and their receptors in viral persistence and liver damage during chronic hepatitis C virus infection

Chemokines produced in the liver during hepatitis C virus(HCV) infection induce migration of activated T cells from the periphery to infected parenchyma.The milieu of chemokines secreted by infected hepatocytes is predominantly associated with the T-helper cell/Tc1 T cell(Th1/Tc1) response.These chemokines consist of CCL3(macrophage inflammatory protein-1α;MIP-1α),CCL4(MIP-1β),CCL5(regulated on activation normal T cell expressed and secreted;RANTES),CXCL10(interferon-γ-inducible protein-10;IP-10),CXCL11(interferon-inducible T-cell α chemoattractant;I-TAC),and CXCL9(monokine induced by interferon γ;Mig) and they recruit T cells expressing either CCR5 or CXCR3 chemokine receptors.Intrahepatic and peripheral blood levels of these chemokines are increased during chronic hepatitis C.The interaction between chemokines and their receptors is essential in recruiting HCV-specific T cells to control the infection.When the adaptive immune response fails in this task,non-specific T cells without the capacity to control the infection are also recruited to the liver,and these are ultimately responsible for the persistent hepatic damage.The modulation of chemokine receptor expression and chemokine secretion could be a viral escape mechanism to avoid specific T cell migration to the liver during the early phase of infection,and to maintain liver viability during the chronic phase,by impairing non-specific T cell migration.Some chemokines and their receptors correlate with liver damage,and CXCL10(IP-10) and CXCR3 levels have shown a clinical utility as predictors of treatment response outcome.The regulation of chemokines and their receptors could be a future potential therapeutic target to decrease liver inflammation and to increase specific T cell migration to the infected liver.

Expression of chemokine receptors CCR3, CCR5 and CXCR3 on CD4^＋ T cells in CBA/J×DBA/2 mouse model, selectively induced by IL-4 and IL-10, regulates the embryo resorption rate

Background Chemokines and their receptors have been a research focus in transplantation immunology. Chemokines and their receptors play a role in lymphocyte recruitment and differentiation process. This study aimed to observe whether IL-4 and IL-10 may regulate the expression of chemokine receptors CCR3, CCR5 and CXCR3 on CD4^＋ T cells in CBA/J×DBA/2 mouse model and to explore the role of CCR3, CCR5, CXCR3 in immune tolerance in pregnancy. Methods The mouse model of spontaneous abortion （CBA/J×DBA/2） and the normal pregnant mouse model （CBA/J×BALB/c） were used. CBA/J×DBA/2 mice were injected with IL-4 （CBA/J×DBA/2-IL-4）, IL-4 and IL-10 （CBA/J×DBA/2-IL-4＋IL-10）, or normal saline （CBA/J×DBA/2-NS） as a control. The expression of CCR3, CCR5 and CXCR3 on CD4^＋ T cells from mouse peripheral blood was measured by the double-labelled FCM method, and the embryo resorption rate was also examined. Results The embryo resorption rate in the CBA/J×DBA/2 group without any treatment was significantly higher than that in the CBA/J×BALB/c group （17.9% vs 3.7%, P 〈0.01）. The embryo resorption rate in the CBA/J×DBA/2 group immunized with IL-4 or IL-4 together with IL-10 was significantly decreased, compared with that in the control and NS groups respectively. CCR3 expression on CD4^＋ T cells in the CBA/J×DBA/2 group without any treatment was significantly lower than that in the CBA/J×BALB/c group （0.3738±0.3575 vs 1.2190±0.2772, P 〈0.01）; both CCR5 （3.0900±1.5603 vs 1.2390±0.6361, P〈0.01） and CXCR3 （2.4715±0.9074 vs 0.9200±0.5585, P 〈0.01） expressions on CD4^＋ T cells of the CBA/J×DBA/2 group without any treatment were significantly higher than those of the CBA/J×BALB/c group. Significant up-regulation of CCR3 and down-regulation of CXCR3 were found in the CBA/J×DBA/2 group treated with IL-4 （CCR3： 2.0360±0.6944, CXCR3： 1.3510±0.5263, P〈0.01） or IL-4 and IL-10 （CCR3： 1.8160±1.0947, CXCR3：1.0940±0.7168, P〈0.01）. Because of the CCR5, IL-4 and IL-10 （1.9400±0.8504 vs 3.0900±1.5603, P 〈0.05）, but IL-4 alone （2.5310±1.3595 vs 3.0900±1.5603, P 〉0.05） treatment significantly decreased the expression of CCR5 in CBA/J×DBA/2. Conclusions The abnormal expression of CCR3, CCR5 and CXCR3 on CD4^＋ T cells may play an important role in the pathogenesis of spontaneous abortion. The pregnancy immune tolerance may be induced through selective induction of CCR3, CCR5 and CXCR3 expressions by IL-4 together with IL-10.

Effect of CO2 pneumoperitoneum on the expression of the chemokine receptors CXCR4 and CCR7 in colorectal carcinoma cells in vitro

Background The ability of pneumoperitoneum in laparoscopic surgery to promote proliferation and metastasis of colorectal cancer has become a focus of research in the field of minimally invasive surgery. The aim of this research was to investigate the effect of CO~ pneumoperitoneum under different pressures and exposed times on the expression of chemokine receptors in colorectal carcinoma cells. Methods We constructed an in vitro pneumoperitoneum model. SW480 colon carcinoma cells were exposed to CO2 pneumoperitoneum under different pressures （6, 9, 12, and 15 mmHg） for 1, 2, and 4 hours. These cells were then cultivated under the same conditions as normal SW480 colon carcinoma cells without CO= pneumoperitoneum （control group）, treated at 37℃, and 5% CO2. The expression of the chemokine receptors CXC receptor 4 （CXCR4） and chemokine C receptor 7 （CCR7） was detected by immunocytochemistry and reverse transcriptase polymerase chain reaction after being cultivated for 0, 24, 48, and 72 hours. Results Immunocytochemistry showed that CXCR4 expression in SW480 cells was significantly decreased in the 6, 9, 12, and 15 mmHg CO2 pneumoperitoneum-treated groups for the same exposure times compared with controls （P 〈0.05）. CCR7 expression in SW480 cells was significantly decreased in the 12 and 15 mmHg CO2 pneumoperitoneum- treated groups compared with controls （P 〈0.05）. CXCR4 and CCR7 expression increased up to the level of the control group after 24 and 48 hours （P 〉0.05）. If the CO2 pneumoperitoneum pressure increased, CXCR4 and CCR7 expression decreased at all exposure times. If the CO2 pneumoperitoneum exposure time prolonged, there were no significant differences in CXCR4 and CCR7 expression under the same pressure. Under all exposure times, CXCR4 and CCR7 mRNA expression was significantly decreased in the 6, 9, 12, and 15 mmHg CO2 pneumoperitoneum-treated groups （P 〈0.05） compared with controls, and it increased up to the level of controls after being cultivated for 48 hours （P 〉0.05）. If the CO2 pneumoperitoneum pressure increased （with all exposure times） and exposure time prolonged （under the same pressure）, there were no significant differences in CXCR4 and CCR7 expression. Conclusions CXCR4 and CCR7 expression is temporarily affected after continuous CO2 pneumoperitoneum treatment. The high pressure of CO2 pneumoperitoneum plays an important role in suppressing the expression of these chemokine receptors. Different lengths of time of exposure to a CO2 pneumoperitoneum-like environment do not change CXCR4 and CCR7 expression.

C-X-C chemokine receptor type 7 antibody enhances neural plasticity after ischemic stroke

Stromal cell-derived factor-1 and its receptor C-X-C chemokine receptor 4(CXCR4) have been shown to regulate neural regeneration after stroke.Howeve r,whether stromal cell-derived factor-1 receptor CXCR7,which is widely distributed in the develo ping and adult central nervous system,participates in neural regeneration remains poorly unde rstood.In this study,we established rat models of focal cerebral ischemia by injecting endothelin-1 into the cerebral co rtex and striatum.Starting on day 7 after injury,CXCR7-neutralizing antibody was injected into the lateral ventricle using a micro drug delivery system for 6 consecutive days.Our results showed that CXCR7-neutralizing antibody increased the total length and number of sprouting co rticospinal tra ct fibers in rats with cerebral ischemia,increased the expression of vesicular glutamate transporter 1 and growth-related protein 43,marke rs of the denervated spinal cord synapses,and promoted the differentiation and maturation of oligodendrocyte progenitor cells in the striatum.In addition,CXCR7 antibody increased the expression of CXCR4 in the striatum,increased the protein expression of RAS and ERK1/2 associated with the RAS/ERK signaling pathway,and im proved rat motor function.These findings suggest that CXCR7 improved neural functional recovery after ischemic stroke by promoting axonal regeneration,synaptogenesis,and myelin regeneration,which may be achieved by activation of CXCR4 and the RAS/ERK1/2 signaling pathway.

Chemokines and their receptors:important mediators to be aware of in neuroregenerative approaches for spinal cord injury

Curative therapy for spinal cord injury （SCI） remains elusive, however identifying options for tailored treatment strategies is in full swing. Like in the brain there are distinct regions in the adult spinal cord that harbor neural progenitor cells （NPCs） （Horner et al., 2000）. This offers the possibility of recruiting these cells in reparative approaches to support endogenous spinal cord regenerative capacities. Hereby, one challenge among many others is to overcome the already re- strictive microenvironment of potential endogenous NPCs, which is considerably akered by ongoing secondary lesion cascades by the initial lesion. Research addressing this aspect identified a plethora of mediators that hinder or promote neuroregeneration where at inflammatory mediators are known to play an essential role.

Chemokine expression in hepatocellular carcinoma versus colorectal liver metastases

AIM： To evaluate and compare the expression profiles of CXCL12 （SDF-1）, CCL19 （MIP-3β）, CCL20 （MIP-3a） and CCL21 （6Ckine, Exodus2） and their receptors on RNA and protein levels in hepatocellular carcinoma （HCC） versus colorectal liver metastases （CRLM） and to elucidate their impact on the carcinogenesis and progression of malignant liver diseases. METHODS： Chemokine expression was analyzed by RT-PCR and ELISA in 11 cases of HCC specimens and in 23 cases of CRLM and corresponding adjacent nontumorous liver tissues, respectively. Expressions of their receptors CXCR4, CCR6 and CCR7 were analyzed by RT- PCR and Western blot analysis in the same cases of HCC and CRLM. RESULTS： Significant up-regulation for CCL20/CCR6 was detected in both cancer types. Moreover, CCL20 demonstrated significant overexpression in CRLM in relation to the HCC tissues. Being significantly up-regulated only in CRLM, CXCR4 displayed an aberrant expression pattern with respect to the HCC tissues. CONCLUSION： Correlation of CXCR4 expression with CRLM suggests CXCR4 as a potential predictive factor for CRLM. High level expression of CCL20 and its receptor CCR6 in HCC and CRLM with marked up-regulation of CCL20 in CRLM in relation to HCC tissues indicates involvement of the CCL20/CCR6 ligand-receptor pair in the carcinogenesis and progression of hepatic malignancies.

Autocrine IL-8 Contributes to Propionibacterium Acnes-induced Proliferation and Differentiation of HaCaT Cells via AKT/FOXO1/Autophagy

Objective Proprionibacterium acnes(P.acnes)-induced inflammatory responses,proliferation and differentiation of keratinocytes contribute to the progression of acne vulgaris(AV).P.acnes was found to enhance the production of interleukin-8(IL-8)by keratinocytes.This study aimed to investigate the role of IL-8 in P.acnes-induced proliferation and differentiation of keratinocytes and the underlying mechanism.Methods The P.acnes-stimulated HaCaT cell(a human keratinocyte cell line)model was established.Western blotting and immunofluorescence were performed to detect the expression of the IL-8 receptors C-X-C motif chemokine receptor 1(CXCR1)and C-X-C motif chemokine receptor 2(CXCR2)on HaCaT cells.Cell counting kit-8(CCK-8)assay,5-ethynyl-20-deoxyuridine(EdU)assay and Western blotting were performed to examine the effects of IL-8/CXCR2 axis on the proliferation and differentiation of HaCaT cells treated with P.acnes,the IL-8 neutralizing antibody,the CXCR2 antagonist(SB225002),or the CXCR1/CXCR2 antagonist(G31P).Western blotting,nuclear and cytoplasmic separation,CCK-8 assay,and EdU assay were employed to determine the downstream pathway of CXCR2 after P.acnes-stimulated HaCaT cells were treated with the CXCR2 antagonist,the protein kinase B(AKT)antagonist(AZD5363),or the constitutively active forkhead box O1(FOXO1)mutant.Finally,autophagy markers were measured in HaCaT cells following the transfection of the FOXO1 mutant or treatment with the autophagy inhibitor 3-methyladenine(3-MA).Results The expression levels of CXCR1 and CXCR2 were significantly increased on the membrane of HaCaT cells following P.acnes stimulation.The IL-8/CXCR2 axis predominantly promoted the proliferation and differentiation of P.acnes-induced HaCaT cells by activating AKT/FOXO1/autophagy signaling.In brief,IL-8 bound to its receptor CXCR2 on the membrane of keratinocytes to activate the AKT/FOXO1 axis.Subsequently,phosphorylated FOXO1 facilitated autophagy to promote the proliferation and differentiation of P.acnes-induced keratinocytes.Conclusion This study demonstrated the novel autocrine effect of IL-8 on the proliferation and differentiation of P.acnes-induced keratinocytes,suggesting a potential therapeutic target for AV.

Foodborne toxin Aflatoxin B_(1)induced glomerular podocyte inflammation through proteolysis of RelA,downregulation of miR-9 and CXCR4/TXNIP/NLRP3 pathway

Aflatoxin B_(1)(AFB_(1))is a naturally-occurring mycotoxin and recognized as the most toxic foodborne toxin,particularly causing damages to kidney.Glomerular podocytes are terminally differentiated epithelial cells.AFB_(1)induces podocyte inflammation,proteinuria and renal dysfunction.Studying the mechanism of AFB_(1)-induced podocyte inflammation and murine kidney dysfunction,we detected that AFB_(1)increased ubiquitindependent degradation of the transcription factor RelA through enhanced interaction of RelA with E3 ubiquitin ligase tripartite motif containing 7(TRIM7)in mouse podocyte clone-5(MPC-5)and mouse glomeruli.Reduction of RelA resulted in decreasing microRNA-9(miR-9)and activating the chemokine receptor 4(CXCR4),thioredoxin interacting protein(TXNIP),and NOD-like receptor pyrin domain-containing 3(NLRP3)signaling axis(CXCR4/TXNIP/NLRP3 pathway),leading to podocyte inflammation.We also determined that downregulation of miR-9 led to CXCR4 expression and the downstream TXNIP/NLRP3 pathway activation.Overexpression of miR-9 or deletion of CXCR4 suppressed AFB_(1)-induced CXCR4/TXNIP/NLRP3 pathway,resulting in alleviating podocyte inflammation and kidney dysfunction.Our findings indicated that ubiquitin-dependent proteolysis of RelA,downregulation of miR-9,and activation of CXCR4/TXNIP/NLRP3 pathway played an essential role in AFB_(1)-induced glomerular podocyte inflammation.Our study revealed a novel mechanism,via RelA,for the control of AFB_(1)’s nephrotoxicity,leading to an effective protection of food safety and public health.

Expression and purification of recombinant human chemokine SDF-1β in E. coli

Objective: To obtain recombinant human SDF-1β expressed in E. colt and purify SDF-lfi with bio-logical activity from the bacterium. Methods: A thioredoxin-SDF-1β fusion protein (26×103) composed of230 amino acid residues was expressed in E. coli AD494 (DE3)pLysS under the induction of IPTG whenpET32a( + )-SDF-1β was used as an expression vector. Purified SDF-lfi was produced through following pro-cedures: Bacteria lysis, metal-chelated affinity chromatography (MAC), enterokinase digestion to separateSDF-lfi from fusion protein, cation exchange chromatography (CEC) and reverse-phase high performance liq-uid chromatography (RP-HPLC). Western blot with anti-SDF-1β monoclonal antibody (mAb), N-terminalamino acid sequencing, ligand-binding assay and cytosensor/microphysiometry were used to investigate thebiochemical characters and biological activities of the purified SDF-1β. Results: From 10% to 15% of totalbacterium protein was expressed as fusion protein. Approximately 400 fig purified SDF-1β (7. 8×103) con-sisting of 71 amino acid residues were produced from 1 L of fermented bacteria. Western blot showed that an-ti-SDF-1β mAb bound with the purified SDF-1β specifically. N-terminal amino acid sequencing indicates thatN-terminus of purified SDF-1β possessed as the same amino acid sequence as nature one. Purified SDF-1β notonly had the binding activity with CXCR4 expressing cells [Kd= (12. 20±2. 99) mnol/L], but also activatedCXCR4 expressing cell signaling specifically in a dose-dependence manner. Conclusion: The purified recombi-nant human SDF-1β produced with this method possesses biochemical characters and biological activities assame as those nature human SDF-1β.

chemokine/chemokine receptor pair CC L20/CC R6 in humancolorectal malignancy:An overview

Chemokines belong to a superfamily of small, cytokinelike proteins, which induce multiple physiological functions, particularly cytoskeletal rearrangement and compartment-specific migration through their interaction with G-protein-coupled receptors. Chemokines and their receptors have been widely acknowledged as essential and selective mediators in leukocyte migration in inflammatory response. It is now established that the chemokine/chemokine receptor system is also used by cancer cells to direct lymphatic and haematogenous spreading and additionally has an impact on the site of metastatic growth of different tumours. In recent years an increasing number of studies have drawn attention to CC-chemokine cysteine motif chemokine ligand 20(CCL20) and its physiological sole receptor CCR6 to play a role in the onset, development and metastatic spread of various gastrointestinal cancer entities. Among various cancer types CCR6 was also demonstrated to be significantly overexpressed in colorectal cancer(CRC) and stimulation by its physiological ligand CCL20 has been reported to promote CRC cell proliferation and migration in vitro. Further, the CCL20/CCR6 system apparently plays a role in the organ-selective liver metastasis of CRC. Here we review the literature on expression patterns of CCL20 and CCR6 and their physiological interactions as well as the currently presumed role of CCL20 and CCR6 in the formation of CRC and the development of liver metastasis, providing a potential basis for novel treatment strategies.

Chemokine receptor 4 gene silencing blocks neuroblastoma metastasis in vitro

This study investigated the effects of small interfering RNA （siRNA）-mediated silencing of chemokine receptor 4 （CXCR4） on the invasion capacity of human neuroblastoma cell line SH-SY5Y in vitro. Three siRNAs targeting CXCR4 were chemically synthesized and individually transfected into SH-SY5Y cells. Expression of CXCR4 mRNA and protein was signiifcantly sup-pressed in transfected cells by all three sequence-speciifc siRNAs compared with control groups. Furthermore, the invasion capacity of SH-SY5Y cells was signiifcantly decreased following trans-fection with CXCR4-speciifc siRNA compared with the control groups. These data demonstrate that down-regulation of CXCR4 can inhibit in vitro invasion of neuroblastoma.

Clinical and prognostic significance of CC chemokine receptor type 8 protein expression in gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GISTs)are the most common mesenchymal neoplasms of the gastrointestinal tract.Surgical resection and tyrosine kinase inhibitors are defined as the main treatments but cannot cure patients with advanced GIST,which eventually develops into recurrence and acquired drug resistance.Therefore,it is necessary to identify prognostic biomarkers and new therapeutic targets for GISTs.CC chemokine receptor type 8(CCR8)protein participates in regulation of immune responses.Recent studies on CCR8 in nonsmall cell lung cancer and colorectal cancer showed that it was highly expressed in tumor-infiltrating regulatory T cells and correlated with a poor prognosis.AIM To detect CCR8 expression in GIST tissues and analyze its relationships with clinicopathological features and prognosis in patients with GISTs.METHODS Tissue samples were used for the tissue microarrays construction.The microarrays were then subjected to immunohistochemical analyses to detect CCR8 expression.Next,Kaplan–Meier analysis was utilized to calculate the survival rate of patients with complete follow-up data,and the potential prognostic value of CCR8 was evaluated by Cox regression analysis.Finally,a Gene Ontology/Kyoto Encyclopedia of Genes and Genomes single-gene enrichment chart of CCR8 was constructed using the STRING database.RESULTS CCR8-positive signals were detected as brown or brown-yellow particles by immunohistochemistry located in the cytoplasm.Among 125 tissue samples,74 had CCR8 high expression and 51 had low or negative expression.Statistical analyses suggested CCR8 was significantly correlated with tumor size,mitotic index,AFIP-Miettinen risk classification and tumor location.Kaplan–Meier and multivariate analyses showed that patients with low or negative CCR8 expression,mitotic index<5/high-power fields(HPF)and tumor diameter<5 cm had a better prognosis.Based on the STRING database,CCR8 was significantly enriched in biological processes such as tumor immunity,T lymphocyte chemotaxis,migration and pathways like the nuclear factor-κB and tumor necrosis factor pathways as well as intestinal immune regulation networks.CONCLUSION CCR8 is a prognostic biomarker for malignant potential of GISTs,with high expression correlated with malignancy and poor prognosis.

Expressions of chemokine receptor CXCR4 and its ligand CXCL12 in salivary adenoid cystic carcinoma

Objective: To examine expressions of chemokine receptor CXCR4 and its ligand CXCL12 in primary focus and lymphogenous metastasis of salivary adenoid cystic carcinoma (ACC) with lung metastasis. Methods: Using immunohistochemical hypersensitivity catalyzed signal amplification (CSA), expressions of chemokine receptor CXCR4 and ligand CXCL12 were detected in tissue specimens from 20 cases of primary cancer focus and lymphogenous metastasis of salivary adenoid cystic carcinoma, of which 7 cases were associated with lung metastasis and 3 with lympogenous metastasis. Twenty cases of tongue carcinoma (including 10 cases with lymphogenous metastasis) and 15 cases of mucoepidermoid carcinoma (including 5 cases with lymphogenous metastasis) were used as the malignant control group;and salivary mixed tumor (n=10), tongue leukoceratosis (n=10) and cervical lymph node reactive hyperplasia (n=10) were used as the benign control group. Results: Expression of CXCR4 in the tissues and lymph metastases of oral and maxillofacial salivary ACC, mucoepidermoid carcinoma and tongue carcinoma was significantly higher than that of the benign control group (P<0.05); expression of CXCR4 in the primary focus of ACC was significantly higher than that of the malignant control group; and expression of CXCR4 in the ACC with lung metastasis was 87.1% (6/7), significantly higher than that without lung metastasis(P<0.01). There was evident positive expression of CXCL12 in endotheliocytes of microvessels within cancer and paracancer tissues and significantly high expression of CXCL12 in lymphogenous metastasis(P<0.05). Conclusion: Chemokine receptor CXCR4 and its ligand CXCL12 may be associated with local invasion and lymphogenous metastasis of oral and maxillofacial cancer, especially with lung metastasis of salivary ACC.

C-C chemokine receptor type 2-overexpressing exosomes alleviated experimental post-stroke cognitive impairment by enhancing microglia/macrophage M2 polarization

BACKGROUND Human-derived mesenchymal stromal cells have been shown to improve cognitive function following experimental stroke.The activity of exosomes has been verified to be comparable to the therapeutic effects of mesenchymal stromal cells.However,the effects of exosomes derived from human umbilical cord mesenchymal stem cells(HUC-MSCs)(ExoCtrl)on post-stroke cognitive impairment(PSCI)have rarely been reported.Moreover,whether exosomes derived from C-C chemokine receptor type 2(CCR2)-overexpressing HUC-MSCs(ExoCCR2)can enhance the therapeutic effects on PSCI and the possible underlying mechanisms have not been studied.AIM To investigate the effects of ExoCtrl on PSCI and whether ExoCCR2 can enhance therapeutic effects on PSCI.METHODS Transmission electron microscopy,qNano®particles analyzer,and Western blotting were employed to determine the morphology and CCR2 expression of ExoCtrl or ExoCCR2.ELISA was used to study the binding capacity of exosomes to CC chemokine ligand 2(CCL2)in vivo.After the intravenous injection of ExoCtrl or ExoCCR2 into experimental rats,the effect of ExoCtrl and ExoCCR2 on PSCI was assessed by Morris water maze.Remyelination and oligodendrogenesis were analyzed by Western blotting and immunofluorescence microscopy.QRT-PCR and immunofluorescence microscopy were conducted to compare the microglia/macrophage polarization.The infiltration and activation of hematogenous macrophages were analyzed by Western blotting and transwell migration analysis.RESULTS CCR2-overexpressing HUC-MSCs loaded the CCR2 receptor into their exosomes.The morphology and diameter distribution between ExoCtrl and ExoCCR2 showed no significant difference.ExoCCR2 bound significantly to CCL2 but ExoCtrl showed little CCL2 binding.Although both ExoCCR2 and ExoCtrl showed beneficial effects on PSCI,oligodendrogenesis,remyelination,and microglia/macrophage polarization,ExoCCR2 exhibited a significantly superior beneficial effect.We also found that ExoCCR2 could suppress the CCL2-induced macrophage migration and activation in vivo and in vitro,compared with ExoCtrl treated group.CONCLUSION CCR2 over-expression enhanced the therapeutic effects of exosomes on the experimental PSCI by promoting M2 microglia/macrophage polarization,enhancing oligodendrogenesis and remyelination.These therapeutic effects are likely through suppressing the CCL2-induced hematogenous macrophage migration and activation.Key words:Cognitive impairment;Stroke;Exosomes;C-C chemokine receptor type 2;Microglia/macrophage polarization;Remyelination.

CX3 chemokine receptor 1 deficiency leads to reduced dendritic complexity and delayed maturation of newborn neurons in the adult mouse hippocampus

Previous studies have shown that microglia impact the proliferation and differentiation of neu- rons during hippocampal neurogenesis via the fractalkine/CX3 chemokine receptor i （CX3CRI） signaling pathway. However, whether microglia can influence the maturation and dendritic growth of newborn neurons during hippocampal neurogenesis remains unclear. In the present study, we found that the number of doublecortin-positive cells in the hippocampus was decreased, and the dendritic length and number of intersections in newborn neurons in the hippocampus were reduced in transgenic adult mice with CX3CR1 deficiency （CX3CRl^GFP/GFe）. Furthermore, after experimental seizures were induced with kainic acid in these CX3CRl-deficient mice, the expression of c-fos, a marker of neuronal activity, was reduced compared with wild-type mice. Collectively, the experimental findings indicate that the functional maturation of newborn neu- rons during hippocampal neurogenesis in adult mice is delayed by CX3CR1 deficiency.

Expression of CC Chemokine Ligand 20 and CC Chemokine Receptor 6 mRNA in Patients with Psoriasis Vulgaris

Summary: In order to explore the possible role of CC chemokine ligand 20 (CCL20) and its receptor CC chemokine receptor 6 (CCR6) in the pathogenesis of psoriasis, the expression levels of mRNA of them in psoriatic lesions were investigated. The skin biopsies were collected from skin lesions in 35 cases of psoriasis vulgaris and 18 normal controls. RT-PCR was used to semi-quantitatively analyze the mRNA expression of CCL20 and CCR6 in the psoriatic lesions and the normal skin tissues. The results showed that the mRNA of CCL20 and CCR6 was present in every specimen. The expression levels of CCL20 mRNA in skin lesions were 1.1397±0.0521, which were greatly higher than those in normal controls (0.8681±0.0308) (P<0.001). The expression levels of CCR6 mRNA in skin lesions were 1.1103±0.0538, significantly higher than in the controls (0.9131±0.0433, P<0.001). These findings indicate that up-regulated expression of CCL20 and CCR6 mRNA might be related to the pathogenesis of psoriasis.