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.

The secondary injury cascade after spinal cord injury:an analysis of local cytokine/chemokine regulation

After spinal cord injury,there is an extensive infiltration of immune cells,which exacerbates the injury and leads to further neural degeneration.Therefore,a major aim of current research involves targeting the immune response as a treatment for spinal cord injury.Although much research has been performed analyzing the complex inflammatory process following spinal cord injury,there remain major discrepancies within previous literature regarding the timeline of local cytokine regulation.The objectives of this study were to establish an overview of the timeline of cytokine regulation for 2 weeks after spinal cord injury,identify sexual dimorphisms in terms of cytokine levels,and determine local cytokines that significantly change based on the severity of spinal cord injury.Rats were inflicted with either a mild contusion,moderate contusion,severe contusion,or complete transection,7 mm of spinal cord centered on the injury was harvested at varying times post-injury,and tissue homogenates were analyzed with a Cytokine/Chemokine 27-Plex assay.Results demonstrated pro-inflammatory cytokines including tumor necrosis factorα,interleukin-1β,and interleukin-6 were all upregulated after spinal cord injury,but returned to uninjured levels within approximately 24 hours post-injury,while chemokines including monocyte chemoattractant protein-1 remained upregulated for days post-injury.In contrast,several anti-inflammatory cytokines and growth factors including interleukin-10 and vascular endothelial growth factor were downregulated by 7 days post-injury.After spinal cord injury,tissue inhibitor of metalloproteinase-1,which specifically affects astrocytes involved in glial scar development,increased more than all other cytokines tested,reaching 26.9-fold higher than uninjured rats.After a mild injury,11 cytokines demonstrated sexual dimorphisms;however,after a severe contusion only leptin levels were different between female and male rats.In conclusion,pro-inflammatory cytokines initiate the inflammatory process and return to baseline within hours post-injury,chemokines continue to recruit immune cells for days post-injury,while anti-inflammatory cytokines are downregulated by a week post-injury,and sexual dimorphisms observed after mild injury subsided with more severe injuries.Results from this work define critical chemokines that influence immune cell infiltration and important cytokines involved in glial scar development after spinal cord injury,which are essential for researchers developing treatments targeting secondary damage after spinal cord injury.

Macrophage migration inhibitory factor facilitates astrocytic production of the CCL2 chemokine following spinal cord injury

Spinal cord injury causes accumulation of a large number of leukocytes at the lesion site where they contribute to excessive inflammation.Overproduced chemokines are responsible for the migratory process of the leukocytes,but the regulatory mechanism underlying the production of chemokines from resident cells of the spinal cord has not been fully elucidated.We examined the protein levels of macrophage migration inhibitory factor and chemokine C-C motif chemokine ligand 2 in a spinal cord contusion model at different time points following spinal cord injury.The elevation of macrophage migration inhibitory factor at the lesion site coincided with the increase of chemokine C-C motif chemokine ligand 2 abundance in astrocytes.Stimulation of primary cultured astrocytes with different concentrations of macrophage migration inhibitory factor recombinant protein induced chemokine C-C motif chemokine ligand 2 production from the cells,and the macrophage migration inhibitory factor inhibitor 4-iodo-6-phenylpyrimidine attenuated the stimulatory effect.Further investigation into the underlying mechanism on macrophage migration inhibitory factor-mediated astrocytic production of chemokine C-C motif chemokine ligand 2 revealed that macrophage migration inhibitory factor activated intracellular JNK signaling through binding with CD74 receptor.Administration of the macrophage migration inhibitory factor inhibitor 4-iodo-6-phenylpyrimidine following spinal cord injury resulted in the reduction of chemokine C-C motif chemokine ligand 2-recruited microglia/macrophages at the lesion site and remarkably improved the hindlimb locomotor function of rats.Our results have provided insights into the functions of astrocyte-activated chemokines in the recruitment of leukocytes and may be beneficial to develop interventions targeting chemokine C-C motif chemokine ligand 2 for neuroinflammation after spinal cord injury.

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.

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.

Blocking postsynaptic density-93 binding to C-X3-C motif chemokine ligand 1 promotes microglial phenotypic transformation during acute ischemic stroke

We previously reported that postsynaptic density-93 mediates neuron-microglia crosstalk by interacting with amino acids 357–395 of C-X3-C motif chemokine ligand 1(CX3 CL1) to induce microglia polarization. More importantly, the peptide Tat-CX3 CL1(comprising amino acids 357–395 of CX3 CL1) disrupts the interaction between postsynaptic density-93 and CX3 CL1, reducing neurological impairment and exerting a protective effect in the context of acute ischemic stroke. However, the mechanism underlying these effects remains unclear. In the current study, we found that the pro-inflammatory M1 phenotype increased and the anti-inflammatory M2 phenotype decreased at different time points. The M1 phenotype increased at 6 hours after stroke and peaked at 24 hours after perfusion, whereas the M2 phenotype decreased at 6 and 24 hours following reperfusion. We found that the peptide Tat-CX3 CL1(357–395 aa) facilitates microglial polarization from M1 to M2 by reducing the production of soluble CX3 CL1. Furthermore, the a disintegrin and metalloprotease domain 17(ADAM17) inhibitor GW280264 x, which inhibits metalloprotease activity and prevents CX3 CL1 from being sheared into its soluble form, facilitated microglial polarization from M1 to M2 by inhibiting soluble CX3 CL1 formation. Additionally, Tat-CX3 CL1(357–395 aa) attenuated long-term cognitive deficits and improved white matter integrity as determined by the Morris water maze test at 31–34 days following surgery and immunofluorescence staining at 35 days after stroke, respectively. In conclusion, Tat-CX3 CL1(357–395 aa) facilitates functional recovery after ischemic stroke by promoting microglial polarization from M1 to M2. Therefore, the Tat-CX3 CL1(357–395 aa) is a potential therapeutic agent for ischemic stroke.

Neuronal chemokines:new insights into neuronal communication after injury

Classically,chemokines were described as small proteins driving leukocyte migration.Nonetheless,more and more studies are showing the great variety of cell functions and tissues in which they participate,including neural cells.During the last years,research has highlighted the importance of chemokines in the nervous system,governing a wide range of processes (MesquidaVeny et al.,2021).This is evidenced for example by the crucial role played by CXCL12 during cortical development,or the homeostatic role of neuronal CX3CL1,preventing microglial activation.We are now certain that many chemokines and their receptors are widely expressed in neurons,and growing evidence has shown them as fundamental players in direct neuronal communication,both during homeostasis and after insult.

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.

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.

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.

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.

Chemokines and their receptors play important roles in the development of hepatocellular carcinoma

The chemokine system consists of four different subclasses with over 50 chemokines and 19 receptors. Their functions in the immune system have been well elucidated and research during the last decades unveils their new roles in hepatocellular carcinoma(HCC). The chemokines and their receptors in the microenvironment influence the development of HCCby several aspects including:inflammation,effects on immune cells,angiogenesis,and direct effects on HCC cells. Regarding these aspects,pre-clinical research by targeting the chemokine system has yielded promising data,and these findings bring us new clues in the chemokine-based therapies for HCC.

Expression of CC Chemokine Ligand 5 in Patients with Rheumatoid Arthritis and Its Correlation with Disease Activity and Medication

Objective To determine the levels of CC chemokine ligand 5 (CCL5) in serum and synovial fluid (SF) from patients with rheumatoid arthritis (RA) and their relations with disease activity and medication. Methods CCL5 in serum and SF was quantified by enzyme-linked immunosorbent assay (ELISA) in 28 RA patients and 21 osteoarthritis (OA) patients. In RA patients, the correlations of CCL5 levels in serum and SF with disease activity were analyzed. Meanwhile, the serum CCL5 levels among RA patients treated with disease-modifying antirheumatic drugs (DMARDs), Tripterygium Glucosides, and other Chinese herbs without disease-modifying effects were also compared. Results CCL5 levels in both serum and SF of RA patients were significantly higher than those of OA patients (P<0.05). Moreover, the level of CCL5 was higher in SF than that in serum of RA patients (P<0.01). Serum CCL5 level was correlated significantly with the number of swollen joints (r=0.3329, P<0.05), erythrocyte sedimentation rate (r=0.4001, P<0.05), and C reactive protein (r=0.3735, P<0.01). In addition, the level of CCL5 had a trend of lower in patients treated with DMARDs or Tripterygium Glucosides than those treated with other Chinese herbs, although the difference was not significant among those patients due to the small number of patients in each group. Conclusions In RA patients, the expression of CCL5 increases and correlates with some clinical and laboratory parameters of RA, which indicate that CCL5 plays an important role in RA and may serve as a useful marker of disease activity. DMARDs and Tripterygium Glucosides might exert their clinical effects through reducing CCL5 production in RA.

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.

Association of gene and protein expression and genetic polymorphism of CC chemokine ligand 4 in colorectal cancer

BACKGROUND Leukocytes,such as T cells and macrophages,play an important role in tumorigenesis.CC chemokine ligand(CCL)4,which is produced by lymphocytes and macrophages,has been found to be expressed in the mucosa of the gastrointestinal tract and is a potent chemoattractant for various leukocytes.AIM To examine CCL4 expression and its genetic polymorphism rs10491121 in patients with colorectal cancer(CRC)and evaluate their prognostic significance.METHODS Luminex technology was used to determine CCL4 Levels in CRC tissue(n=98),compared with paired normal tissue,and in plasma from patients with CRC(n=103),compared with healthy controls(n=97).Included patients had undergone surgical resection for primary colorectal adenocarcinomas between 1996 and 2019 at the Department of Surgery,Ryhov County Hospital,Jönköping,Sweden.Reverse transcription quantitative PCR was used to investigate the CCL4 gene expression in CRC tissue(n=101).Paired normal tissue and TaqMan single nucleotide polymorphism assays were used for the CCL4 rs10491121 polymorphism in 610 CRC patients and 409 healthy controls.RESULTS The CCL4 protein and messenger RNA expression levels were higher in CRC tissue than in normal paired tissue(90%,P<0.001 and 45%,P<0.05,respectively).CRC tissue from patients with localized disease had 2.8-fold higher protein expression levels than that from patients with disseminated disease.Low CCL4 protein expression levels in CRC tissue were associated with a 30%lower cancer-specific survival rate in patients(P<0.01).The level of plasma CCL4 was 11%higher in CRC patients than in healthy controls(P<0.05)and was positively correlated(r=0.56,P<0.01)with the CCL4 protein level in CRC tissue.The analysis of CCL4 gene polymorphism rs10491121 showed a difference(P<0.05)between localized disease and disseminated disease in the right colon,with a dominance of allele A in localized disease.Moreover,the rate of the A allele was higher among CRC patients with mucinous cancer than among those with nonmucinous cancer.CONCLUSION The present study indicates that the CRC tissue levels of CCL4 and CCL4 gene polymorphism rs10491121,particularly in the right colon,are associated with clinical outcome in CRC patients.

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.

Role of chemokines in the hepatocellular carcinoma microenvironment and their translational value in immunotherapy

The difficulty of early diagnosis,high tumor heterogeneity,and high recurrence and metastasis rates lead to an unsatisfactory treatment status for hepatocellular carcinoma(HCC).HCC is a typical inflammation-driven tumor.Chronic inflammation allows nascent tumors to escape immunosurveillance.Chemokines are small,soluble,secreted proteins that can regulate the activation and trafficking of immune cells during inflammation.Several studies have shown that various chemokines with overarching functions disrupt the immune microenvironment during the initiation and progression of HCC.The dysregulated chemokine network in HCC contributes to multiple malignant processes,including angiogenesis,tumor proliferation,migration,invasion,tumor low response,and resistance to immune therapy.Here,we summarize the current studies focusing on the role of chemokines and their receptors in the HCC immune microenvironment,highlighting potential translational therapeutic uses for modulating the chemokine system in HCC.

Functions and mechanisms of chemokine receptor 7 in tumors of the digestive system

Chemokine(C-X-C motif)receptor 7(CXCR7),recently termed ACKR3,belongs to the G protein-coupled cell surface receptor family,binds to stromal cellderived factor-1[SDF-1,or chemokine(C-X-C motif)ligand 12]or chemokine(CX-C motif)ligand 11,and is the most common chemokine receptor expressed in a variety of cancer cells.SDF-1 binds to its receptor chemokine(C-X-C motif)receptor 4(CXCR4)and regulates cell proliferation,survival,angiogenesis and migration.In recent years,another new receptor for SDF-1,CXCR7,has been discovered,and CXCR7 has also been found to be expressed in a variety of tumor cells and tumor-related vascular endothelial cells.Many studies have shown that CXCR7 can promote the growth and metastasis of a variety of malignant tumor cells.Unlike CXCR4,CXCR7 exhibits a slight modification in the DRYLAIV motif and does not induce intracellular Ca^2+release following ligand binding,which is essential for recruiting and activating G proteins.CXCR7 is generally thought to work in three ways:(1)Recruitingβ-arrestin 2;(2)Heterodimerizing with CXCR4;and(3)Acting as a“scavenger”of SDF-1,thus lowering the level of SDF-1 to weaken the activity of CXCR4.In the present review,the expression and role of CXCR7,as well as its prognosis in cancers of the digestive system,were investigated.

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.

Expression of mRNA of chemokines and chemokine receptors and cytokines amount in the blood of healthy volunteers

Background: Chemokines are small proteins that activate immune system in normal and pathological conditions. The induction of chemotaxis is a well-established role of chemokines. Moreover chemokines are important mediators of angiogenesis, implantation of fetus, and maturation of immune cells. In human body many types of cells express chemokines and cytokines at level of gene and protein. In blood cells chemokine and chemokine receptors mRNA level is a one of crucial points of chemokine system condition. The aim of the study was to evaluate the relationship between plasma concentration of cyto- kines and chemokines/chemokine receptors mRNA level in blood of healthy volunteers. Results: Gene expression of eotaxin, eotaxin-2, IL-8, MIP-1α, MIP- 1β, RANTES, CCR1, CCR3, CCR5, CXCR1, and CXCR2 was measured in peripheral blood cells, as well as the concentration of IL-1β, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p70), IL-13, IL-15, IL-17, eotaxin, FGF-2, G-CSF, GM-CSF, IFN-γ, IP-10, MCP-1, MIP-1α, MIP-1β, PDGF-BB, RANTES, TNF-α, and VEGF was evaluated in the plasma of 19 healthy individuals. We studied rela- tionship between mRNA levels of chemokines/recaptors and cytokine concentration in blood of healthy volunteers. Conclusion: These data are allowed to assess chemokines impact in the cytokine regulation of healthy subjects. These results indicate that chemokines and their receptors is diverse and redundant system of immune reactivity in response to internal and external challenges.