Mucosal CCR1 gene expression as a marker of molecular activity in Crohn's disease: preliminary data

AIM

A series of mechanisms of immune response, inflammation and apoptosis have been demonstrated to contribute to the appearance and evolution of Crohn's disease (CD) through the overexpression of several cytokines and chemokines in a susceptible host. The aim of this study was to identify the differences in gene expression profiles analyzing a panel of candidate genes in the mucosa from patients with active CD (CD-A), patients in remission (CD-R), and normal controls.

PATIENTS, MATERIALS AND METHODS

Nine individuals were enrolled in the study: six CD patients (three with active lesions, three with mucosal healing) and three controls without inflammatory bowel disease (IBD) seen on endoscopy. All the individuals underwent mucosal biopsy during colonoscopy. Gene expression levels of 84 genes previously associated with CD were evaluated by polymerase chain reaction (PCR) array.

RESULTS

Ten genes out of 84 were found significantly differentially expressed in CD-A (CCL11, CCL25, DEFA5, GCG, IL17A, LCN2, REG1A, STAT3, MUC1, CCR1) and eight genes in CD-R (CASP1, IL23A, STAT1, STAT3, TNF, CCR1, CCL5, and HSP90B1) when compared to controls. A quantitative gene expression analysis revealed that CCR1 gene was more expressed in CD-A than in CD-R.

CONCLUSIONS

Our data suggest that CCR1 gene may be a putative marker of molecular activity of Crohn's disease. Following these preliminary data, a confirmation in larger cohort studies could represent a useful method in order to identify new therapeutic targets.

Chemokine CCL15 Mediates Migration of Human Bone Marrow-Derived Mesenchymal Stem Cells Toward Hepatocellular Carcinoma

Mesenchymal stem cells (MSCs) possess the ability to migrate toward tumor sites and are regarded as promising gene delivery vehicles for cancer therapeutics. However, the factors that mediate this tropism have yet to be completely elucidated. In this study, through cytokine array analysis, chemokine CCL15 was found to be the most abundant protein differentially expressed in hepatocellular carcinoma (HCC) cell lines compared with a normal liver cell line. Serum CCL15 levels in HCC patients determined by enzyme linked immunosorbent assay were shown to be profoundly elevated compared with healthy controls. Immunohistochemical analysis indicated that CCL15 expression was much stronger in HCC tumor tissues than in adjacent nontumor tissues. Transwell migration assay suggested that CCL15 may be involved in chemotaxis of human MSCs (hMSCs) toward HCC in vitro and that this chemotactic effect of CCL15 is mediated via CCR1 receptors on hMSCs. Orthotopic animal models of HCC were established to investigate the role of CCL15 in hMSCs migration toward HCC in vivo. Both histological and flow cytometric analysis showed that significantly fewer hMSCs localized within 97H-CCL15-shRNA xenografts compared with 97H-green fluorescent protein xenografts after intravenous delivery. Finally, the possible effects of hMSCs on HCC tumor growth were also evaluated. Coculture experiments showed that hMSCs had no apparent effect on the proliferation of HCC cells in vitro In addition, systemic administration of hMSCs did not affect HCC tumor progression in vivo. Our data in this study help to elucidate the mechanism underlying the homing capacity of hMSCs toward HCC.

A novel role for CCL3 (MIP-1α) in myeloma-induced bone disease via osteocalcin downregulation and inhibition of osteoblast function

Upregulation of cytokines and chemokines is a frequent finding in multiple myeloma (MM). CCL3 (also known as MIP-1α) is a pro-inflammatory chemokine, levels of which in the MM microenvironment correlate with osteolytic lesions and tumor burden. CCL3 and its receptors, CCR1 and CCR5, contribute to the development of bone disease in MM by supporting tumor growth and regulating osteoclast (OC) differentiation. In this study, we identify inhibition of osteoblast (OB) function as an additional pathogenic mechanism in CCL3-induced bone disease. MM-derived and exogenous CCL3 represses mineralization and osteocalcin production by primary human bone marrow stromal cells and HS27A cells. Our results suggest that CCL3 effects on OBs are mediated by ERK activation and subsequent downregulation of the osteogenic transcription factor osterix. CCR1 inhibition reduced ERK phosphorylation and restored both osterix and osteocalcin expression in the presence of CCL3. Finally, treating SCID-hu mice with a small molecule CCR1 inhibitor suggests an upregulation of osteocalcin expression along with OC downregulation. Our results show that CCL3, in addition to its known catabolic activity, reduces bone formation by inhibiting OB function, and therefore contributes to OB/OC uncoupling in MM.

CCR1 expression and signal transduction by murine BMMC results in secretion of TNF-alpha, TGFbeta-1 and IL-6

Chemokine receptors (CCRs) are important co-stimulatory molecules found on many blood cells and associated with various diseases. The expression and function of CCRs on mast cells has been quite controversial. In this study, we report for the first time that murine bone marrow-derived mast cells (BMMC) express messenger RNA and protein for CCR1. BMMC cultured in the presence of murine recombinant stem cell factor and murine IL-3 expressed CCR1 after 5-6 weeks. We also report for the first time that mBMMC(CCR1+) cells endogenously express neurokinin receptor-1 and intercellular adhesion molecule-1. To examine the activity of CCR1 on these BMMC, we simultaneously stimulated two receptors: CCR1 by its ligand macrophage inflammatory protein-1alpha and the IgE receptor FcepsilonRI by antigen cross-linking. We found that co-stimulation enhanced BMMC degranulation compared with FcepsilonRI stimulation alone, as assessed by beta-hexosaminidase activity (85 versus 54%, P < 0.0001) and Ca(2+) influx (223 versus 183 nM, P < 0.05). We also observed significant increases in mast cell secretion of key growth factors, cytokines and chemokine mediators upon CCR1-FcepsilonRI co-stimulation. These factors include transforming growth factor beta-1, tumor necrosis factor-alpha and the cytokine IL-6. Taken together, our data indicate that CCR1 plays a key role in BMMC function. These findings contribute to our understanding of mechanisms for immune cell trafficking during inflammation.

Levels of chemokine receptors expressed on peripheral blood T lymphocytes of Egyptian patients with hepatocellular carcinoma

CC chemokine receptors (CCR) have an important role in the recruitment of leukocytes to the site of inflammation. The migration and metastasis of tumor cells shares many similarities with leukocyte trafficking, which is mainly regulated by chemokine receptor-ligand interactions. CCR1 and CCR5 are highly expressed in hepatocellular carcinoma (HCC) cells and tissues with unknown functions. In this study, we estimated the surface expression of chemokine receptors CCR1 and CCR5 on the lymphocytes of peripheral blood from patients with HCC in an attempt to identify their roles in tumorigenesis. The study was conducted on 52 patients of which, 24 of them with confirmed HCC and 28 with chronic hepatitis C virus infection. In addition, 20 apparently healthy controls with matched age and sex were also included in the study. All patient and control groups were subjected to the following: thorough history taking, clinical examination, abdominal ultrasonography and fine needle liver biopsy for patient's group when needed, complete blood count, liver function tests, viral markers for hepatitis B and C, serum alpha fetoprotein and flowcytometric detection of chemokine receptors CCR1 and CCR5 on peripheral blood T lymphocytes. The expression of chemokine receptors CCR1 and CCR5 on CD4+ and CD8+ T lymphocytes was significantly less in HCC and hepatitis C patient groups as compared to control group. Moreover, a significant decrease in the levels of CCR1 and CCR5 on CD8+ T lymphocytes was detected in HCC patients compared to patients with chronic HCV; however, it was not statistically significant for CD4+ cells. Furthermore in HCC patients, levels of CCR1 and CCR5 were significantly less in patients with large tumor size than small sized tumor. Data obtained showing reduced surface expression of CCR1 and CCR5 on CD4 and CD8 T lymphocytes reflect their possible role in altering the host's immune defense and disease pathogenesis, thus may be helpful for therapy design to ameliorate disease progression.

[Chronic HCV-infection and expression of mRNA of CC-chemokines and their receptors]

The aim of this study was to evaluate some patterns in expression of CC-chemokines (MIP-1alpha, MIP-1beta, MCP-1, RANTES) and their receptors (CCR1, CCR2, CCR3, CCR5) in peripheral blood leukocytes and liver biopsy samples from 21 patients with chronic hepatitis C. 10 healthy subjects were included in the control group. In patients with chronic HCV-infection significant increase of MCP-1 mRNA in liver tissue was observed as the disease progressed. Moreover, content of MCP-1 mRNA was significantly higher in liver as compared with blood. Level of MCP-1 mRNA in liver was directly related with histological changes. Levels of mRNA of CCR1, CCR2, CCR3, and CCR5 in blood of patients with minimal histological manifestations of chronic HCV-infection were significantly lower than in patients with more marked lesions. Expression of CCR1 and CCR5 mRNA in blood was directly correlated with histological activity index and degree of fibrosis. Conducted study demonstrates that progression of chronic hepatitis C is realized through local activation of MCP-1 mRNA synthesis leading to systemic response which manifested by increase of expression of CCR1, CCR2, CCR3, and CCR5 in peripheral blood leukocytes.

The cannabinoid delta-9-tetrahydrocannabinol mediates inhibition of macrophage chemotaxis to RANTES/CCL5: linkage to the CB2 receptor

The chemotactic response of murine peritoneal macrophages to RANTES/CCL5 was inhibited significantly following pretreatment with delta-9-tetrahydrocannabinol (THC), the major psychoactive component in marijuana. Significant inhibition of this chemokine directed migratory response was obtained also when the full cannabinoid agonist CP55940 was used. The CB2 receptor-selective ligand O-2137 exerted a robust inhibition of chemotaxis while the CB1 receptor-selective ligand ACEA had a minimal effect. The THC-mediated inhibition was reversed by the CB2 receptor-specific antagonist SR144528 but not by the CB1 receptor-specific antagonist SR141716A. In addition, THC treatment had a minimal effect on the chemotactic response of peritoneal macrophages from CB2 knockout mice. Collectively, these results suggest that cannabinoids act through the CB2 receptor to transdeactivate migratory responsiveness to RANTES/CCL5. Furthermore, the results suggest that the CB2 receptor may be a constituent element of a network of G protein-coupled receptor signal transductional systems, inclusive of chemokine receptors, that act coordinately to modulate macrophage migration.

Migration deficit in monocyte-macrophages in human ovarian cancer

PURPOSE

To examine the migration responses of monocyte/macrophages (MO/MA) expressing complementary receptors to chemokines produced in the tumor environment of epithelial ovarian cancer (EOC).

METHODS

We examined the expression of the chemokine receptors, CCR1, CCR5, and CXCR4, on EOC associated ascitic and blood MO/MA; their response to complementary chemokines in a MO/MA migration assay and the F-actin content in an actin polymerization assay. A validated cDNA microarray assay was then utilized to examine alterations in pathway genes that can be identified with cell migration.

RESULTS

Ascitic and EOC blood MO/MA express CCR1, CCR5 and CXCR4, but differently. Cell surface expression levels for CCR1 and CCR5 were higher in ascites than that of normal blood in contrast to CXCR4 levels in ascitic MO/MA which were lower. EOC associated ascitic or blood MO/MA failed to migrate in response to the CC ligand RANTES and to the CXCR4 reactive chemokine, SDF1 (CXCL12). Ascitic and most EOC blood MO/MA also behaved differently from normal blood MO in the polymerization/depolymerization assay. A cDNA gene analysis of purified ascitic MO/MA demonstrated that a number of genes involved with chemokine production, focal adhesion, actin cytoskeletal function and leukocyte transendothelial migration were down-regulated in the ascitic MO/MA when compared to normal blood MO. Moreover, PBMC cDNA from EOC patients' blood also showed gene profiles similar to that of ascitic MO/MA.

CONCLUSIONS

Defective migration and polymerization/depolymerization activity of MO/MA from EOC patients and a significant down-regulation of critical pathway genes suggest that other mechanisms might be involved in the accumulation of systemically derived MO at the tumor site of EOC patients.