Expression Of GRO-alpha Research Articles

Obesity in pregnancy is associated with macrophage influx and an upregulated GRO-alpha and IL-6 expression in the decidua

About one third of all reproductive-aged women are affected by obesity. Maternal obesity is linked to an adverse outcome for both mother and child. The expression of the pro-inflammatory IL-6 and GRO-alpha as well as the infiltration of macrophages in the placenta of obese, non-diabetic pregnancies was examined by immunohistochemistry in comparison to the placenta of normal weight women. In obese pregnancies the influx of macrophages was significantly increased (p = 0.012). The protein expression of IL-6 and GRO-alpha was significantly elevated (p = 0.036 and p < 0.001, respectively) in the decidua of adipose females.

Development of novel antiangiogenic compounds for colorectal cancer using a tumor explant model and zebrafish.

e14101 Background: The treatment of metastatic colorectal cancer has significantly improved with the development of novel molecularly targeted drugs such as bevacizumab (Avastin); however response rates are modest (40%). There is an urgent need for the development of newer drugs which target angiogenesis and inflammation more effectively. Historically, initial drug screening has been performed using monolayer cell cultures, but these do not effectively present the entire tumour microenvironment. Novel models are required to investigate newer target lead drugs. Methods: Chemical screens of randomized drug libraries were performed in zebrafish to identify drugs that inhibit developmental angiogenesis. Two lead drugs were then tested using human ex vivo colorectal explants to examine their potential to inhibit angiogenic and inflammatory protein secretions for the following factors VEGF, MCP-1, GRO-alpha, IL-6, TNF, IL-8 and IL-1β. Human explants from 5 patients were cultured for 72 hours, and levels of the above factors were assessed using ELISA. Results: Compound 11B and 11F significantly inhibit intersegmental vessel development in zebrafish. Compound 11B (1 μM) reduced the expression of IL-6 (p=0.02) and the 10 µM concentration reduced the expression of VEGF (p=0.047), IL-6 (p=0.02) and IL-1β (p=0.01). Compound 11F (1 μM) reduced the expression of VEGF (P=0.025) and the 10 µM concentration reduced the expression of VEGF (p=0.01) and IL-1β (p=0.01). Bevacizumab (1 μM) reduced the expression of VEGF (p=0.01) and IL-6 (p=0.02) and the 10 µM concentration reduced the expression of VEGF (p=0.003) and IL-6 (p=0.02). Bevacizumab or the other drugs did not affect the expression of MCP-1, GRO-alpha, TNF and IL-8. Conclusions: These studies have characterised two novel compounds with the potential to become important anti-angiogenic drugs in colorectal cancer.

Epstein‐Barr virus infection in immortalized nasopharyngeal epithelial cells: Regulation of infection and phenotypic characterization

Epstein-Barr virus (EBV) infection has been postulated to be an early event involved in the pathogenesis of nasopharyngeal carcinomas (NPC). The lack of representative premalignant nasopharyngeal epithelial cell system for EBV infection has hampered research investigation into the regulation and involvement of EBV infection in NPC pathogenesis. We have compared the efficiency of EBV infection in nasopharyngeal epithelial cells with different biological properties including immortalized, primary and cancerous nasopharyngeal epithelial cells. EBV infection could be achieved in all the nasopharyngeal epithelial cells examined with variable infection rate. TGF-beta effectively enhanced EBV infection into nasopharyngeal epithelial cells both in the immortalized and primary nasopharyngeal epithelial cells. Stable infection of EBV was achieved in a telomerase-immortalized nasopharyngeal epithelial cell line, NP460hTert. The expression pattern of EBV-encoded genes and biological properties of this EBV infected cell line on long-term propagation were monitored. The EBV-infected nasopharyngeal epithelial cells acquired anchorage-independent growth and exhibited invasive growth properties on prolonged propagation. A distinguished feature of this EBV-infected nasopharyngeal epithelial cell model was its enhanced ability to survive under growth factor and nutrient starvation. This was evidenced by the suppressed activation of apoptotic markers and sustained activation of pAkt of EBV-infected cells compared to control cells under nutrient starvation. Examination of cytokine profiles of EBV-infected NP460hTert cells to nutrient and growth factor deprivation revealed upregulation of expression of MCP-1 and GRO-alpha. The establishment of a stable EBV infection model of premalignant nasopharyngeal epithelial cells will facilitate research investigation into the pathogenic role of EBV in NPC development.

Prostaglandin I2 Analogues Enhance Growth-Related Oncogene-α Expression in Human Monocyte-Derived Dendritic Cells

Chemokines for neutrophils such as growth-related oncogene-alpha (GRO-alpha) are important in patients with refractory or severe asthma. Prostaglandin I(2) (PGI(2)) analogues were regarded as potential treatments for asthma. Dendritic cells (DCs) are the professional antigen-presenting cells and play a critical role in regulating immune response. However, it is unknown whether PGI(2) analogues have regulatory effects on GRO-alpha expression in human monocyte-derived DCs (MDDCs). The human MDDCs were pretreated with iloprost and treprostinil (two PGI(2) analogues) or forskolin, a cyclic adenosine monophosphate (cAMP) activator, before stimulation with lipopolysaccharide (LPS). In some cases, I prostanoid (IP) receptor and E prostanoid (EP) antagonists were pretreated before PGI(2) analogue treatment. To investigate the intracellular signaling, nuclear factor (NF)-kappaB inhibitor and the mitogen-activated protein kinase (MAPK) inhibitors were pretreated before PGI(2) analogue treatment. GRO-alpha was measured by enzyme-linked immunosorbent assay. Intracellular signaling was also investigated by Western blot. Iloprost and treprostinil enhanced LPS-induced GRO-alpha expression in MDDCs. This effect could be reversed by an I prostanoid receptor antagonist, CAY10449, but not EP receptor antagonists. Forskolin conferred a similar modulating effect as that noted in iloprost- and treprostinil-treated MDDCs. PGI(2) analogue-enhanced LPS-induced GRO-alpha expression was reduced by MAPK-p38 inhibitor, SB203580. PGI(2) analogues enhanced LPS-induced phospho-p38 expression. PGI(2) analogues enhanced LPS-induced GRO-alpha expression via the IP receptor-cAMP and p38-MAPK pathways in human MDDCs, which may further recruit neutrophil accumulation and adversely affect patients with refractory or severe asthma because of airway neutrophilia. These effects should be considered for PGI(2) analogues as candidates for the treatment of asthma.

Bioactive Lipids Lysophosphatidic Acid and Sphingosine 1-Phosphate Mediate Breast Cancer Cell Biological Functions Through Distinct Mechanisms

Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are structurally related bioactive lipids with growth factor-like activities. LPA and S1P are naturally produced in vivo by blood platelets upon platelet aggregation and at least in vitro by fibroblasts, adipocytes, and multiple types of tumor cells. Breast cancer cells respond to LPA and S1P. However, their specific actions on breast cancer cell biological functions remain unclear. We therefore conducted an in vitro side-by-side study of these two lipids on breast cancer cells. LPA mediates human breast cancer MDA-BO2 cell proliferation, migration, and invasion through activation of a G(alpha i)/ERK1/2-dependent signaling pathway, whereas activation of G(alpha i)/PI3K predominates upon S1P stimulation. In MDA-BO2 cells, LPA but not S1P activities were dependent on active type 1 insulin-like growth factor and epithelial growth factor receptors. LPA and S1P act directly on endothelial cells to induce angiogenesis. We demonstrate that LPA and S1P have indirect angiogenic properties as judged by induced secretion of angiogenic factors by breast cancer cells primed with these lysophospholipids. S1P, but not LPA, controlled the expression of VEGF-A by breast cancer cells, while LPA, but not S1P, controlled the expression of GM-CSF, Gro-alpha, MCP-1, and IL-6. According to the secretion of these paracrine osteoclastic factors, LPA, but not S1P, stimulates breast cancer cell-induced osteoclastogenesis. These findings suggest that, in vivo, LPA and S1P can coordinate their action on tumor and surrounding cells to induce breast cancer progression both at primary and bone metastatic sites.

Fine urban atmospheric particulate matter modulates inflammatory gene and protein expression in human bronchial epithelial cells

Ambient particulate matter (PM) is known to induce inflammation in the respiratory tract of exposed subjects. The aim of the present study was to detect, in bronchial epithelial cells, candidate inflammatory genes exhibiting transcriptional modifications following urban PM2.5 exposure. Paris urban PM2.5 sampled either at a curbside or a background station in winter and in summer was tested in comparison with diesel exhaust particles (DEP) at 10 microg/cm2 on human bronchial epithelial (16-HBE) cells (18 h of exposure). The gene profiling study performed using a 375 cDNA cytokine expression array highlighted the differential expression of certain genes, three of which were selected as genes of interest: the IL-1 alpha cytokine, the GRO-alpha chemokine, and amphiregulin, a ligand of the EGF receptor. Their increased expression was confirmed by RT-PCR and/or by Northern blotting in bronchial epithelial cells. In the culture medium of particle-treated cultures, increased release of GRO-alpha and amphiregulin was shown. The particle component responsible for protein release varied for the two genes. The organic extract seemed to be mainly involved in amphiregulin expression and secretion, whereas both the aqueous and organic extracts induced GRO-alpha release. In conclusion, in bronchial epithelial cells, Paris PM2.5 increased mRNA and protein expression of GRO-alpha and AR involved in the chemoattraction process and bronchial remodeling, respectively.

The chemokine GRO-α (CXCL1) confers increased tumorigenicity to glioma cells

The chemokine GRO-alpha (CXCL1) has been found to mediate the proliferation of glia progenitor cells during neural development. As malignant gliomas are thought to arise from glia progenitors or their differentiated counterparts, astrocytes or oligodendrocytes, we have investigated whether GRO-alpha regulates the tumor characteristics of glioma cells. We found first that resected glioma specimens were strongly immunoreactive for GRO-alpha expression in cells with the morphology of tumor cells. In culture, the U251 glioma line transfected to overexpress GRO-alpha had elevated levels of motility and invasiveness. GRO-alpha transfectants increased their expression of several proteins associated with migratory behavior, including matrix metalloproteinase-2, beta1-integrin and SPARC. The implantation of GRO-alpha glioma clones into the brain of nude mice caused the early demise of mice and this was associated with the formation of larger intracerebral tumors when compared with mice implanted with vector control lines. These results implicate GRO-alpha in gliomas and suggest that the dysregulation of a glia proliferative factor contributes to tumorigenesis. Targeting GRO-alpha may be a useful therapeutic tool to control brain tumor biology.

Tumor necrosis factor‐α increases chemokine gene expression and production in synovial fibroblasts from human temporomandibular joint

Synovitis, which is characterized by infiltration of inflammatory cells, often accompanies progression of clinical symptoms of the temporomandibular joint (TMJ). Synovial fibroblasts of the TMJ are believed to play important roles in progression of synovitis. The purpose of this study was to examine production and gene expression of chemokines by synovial fibroblasts stimulated by tumor necrosis factor-alpha (TNF-alpha). Protein levels of chemokines were measured by enzyme-linked immunosorbent assay (ELISA). Gene expression of chemokines was analyzed by real-time polymerase chain reaction (PCR). Production of interleukin (IL)-8, growth-related oncogene (GRO)-alpha, monocyte chemoattractant protein (MCP)-1, and regulated upon activation normal T-cell expressed and secreted (RANTES) protein by synovial fibroblasts was increased by TNF-alpha. In contrast, stromal cell-derived factor (SDF)-1alpha, macrophage inflammatory protein (MIP)-1alpha and -1beta were not detectable in conditioned media of synovial fibroblasts, with or without TNF-alpha treatment. Increases in gene expression of IL-8, GRO-alpha, MCP-1, and RANTES in response to TNF-alpha treatment were detected. Increased protein production and gene expression of chemokines by synovial fibroblasts in response to TNF-alpha treatment appears to play an important role in recruitment of inflammatory cells into synovium and the progression of synovitis in the TMJ.

Polyinosinic-Polycytidylic Acid Induces the Expression of GRO-α in BEAS-2B Cells

Growth-related oncogene protein-alpha (GRO-alpha)/CXCLl is a chemokine that activates neutrophils and plays an important role in inflammatory reactions. Polyinosinic-polycytidylic acid (poly IC) is a synthetic double-stranded RNA (dsRNA), which is a ligand for Toll-like receptor-3. Poly IC mimics viral infection when applied to cells and induces inflammatory and immune responses. In the present study, we found the induction of GRO-alpha in BEAS-2B bronchial epithelial cells treated with poly IC. Pretreatment of cells with 2-aminopurine, an inhibitor for dsRNA-dependent protein kinase (PKR), inhibited the expression of GRO-alpha-induced by poly IC. Overexpression of interferon-regulatory factor-3 (IRF-3) or retinoic-acid inducible gene-I (RIG-I) enhanced the induction of GRO-alpha by poly IC. PKR, IRF-3, and RIG-I may be involved in the poly IC-induced expression of GRO-alpha in BEAS-2B cells. Airway viral infection may elicit GRO-alpha expression in the bronchial epithelium, which may be implicated in inflammatory and immune reactions.

Clinical Isolates of Staphylococcus aureus Vary in Ability to Stimulate Cytokine Expression in Human Endothelial Cells

Human umbilical vein endothelial cells (HUVEC) were infected for 24 h with 18 well-characterized Staphylococcus aureus isolates, and the supernatants from infected HUVEC were analysed for interleukin (IL)-1beta, tumour necrosis factor-alpha, IL-6, IL-8, IL-10, IL-12p70, growth-related oncogene (GRO)-alpha, granulocyte macrophage colony-stimulating factor (GM-CSF) and regulated upon activation, normal T cell expressed and secreted (RANTES) by immunoassay. All staphylococcal isolates induced the expression of IL-6, IL-8, GRO-alpha, GM-CSF and RANTES. The magnitude of cytokine expression varied between isolates. Staphylococcus aureus inducing high expression of one of these cytokines also showed simultaneous high expression of the other four, indicating a common mechanism for the ability of individual S. aureus to induce expression of these cytokines. No direct correlation between cytokine expression and adhesion of S. aureus to HUVEC was observed, indicating that bacterial properties besides adhesion contribute to the activation of HUVEC.

Activation of Bronchial Epithelial Cells in Smokers Without Airway Obstruction and Patients With COPD

The aim of this study was to investigate the basal level as well as the tumor necrosis factor (TNF)-alpha- and interferon (IFN)-gamma-induced expression and release of the neutrophil chemoattractants interleukin (IL)-8 and growth-related oncogene (GRO)-alpha in primary bronchial epithelial cells (PBECs) from smokers without airflow obstruction and patients with COPD. In addition, the expression of both TNF-alpha-receptor subtypes--p55 TNF-receptor subtype (TNF-R55) and p75 TNF-receptor subtype (TNF-R75)--was quantified in PBECs. PBECs from eight smokers without airflow limitation and eight patients with COPD were stimulated with 50 ng/mL of TNF and 200 U/mL of IFN-gamma for 4 h along with unstimulated time controls. The transcriptional expression and protein release were quantitatively assessed by means of real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Basal level messenger RNA (mRNA) expression and protein release of IL-8 and GRO-alpha were not significantly different between both groups, although a trend toward higher IL-8 levels was seen in patients with COPD. TNF-alpha induced significantly higher mRNA amounts of IL-8 (p = 0.005) and GRO-alpha (p = 0.007) in patients with COPD. This was accompanied by higher protein release data for IL-8 (p = 0.005) and GRO-alpha (p = 0.007). IFN-gamma had no significant effect on the mRNA expression and protein release of IL-8 and GRO-alpha in either group. TNF-R55 and TNF-R75 were detectable in PBECs. However, no significant differences were found between both groups with respect to steady-state mRNA levels of TNF-alpha-receptor subtypes. PBECs from patients with COPD show significantly higher TNF-alpha-induced release of the neutrophil chemoattractant CXC-chemokines IL-8 and GRO-alpha compared to smokers without airflow limitation. This increased activation of PBECs may contribute to the predominance of neutrophils seen in the airway lumen of patients with COPD.

Effect of MG132, a proteasome inhibitor, on the expression of growth related oncogene protein-alpha in human umbilical vein endothelial cells.

Growth related oncogene protein-alpha (GRO-alpha) is a member of C-X-C chemokine and plays an important role in inflammatory responses. Expression of GRO gene family is regulated by a number of factors at both transcriptional and posttranscriptional levels. In the present study, we have addressed the possible regulation of GRO-alpha expression by ubiquitin-proteasome system. Cultures of human umbilical vein endothelial cells were treated with a proteasome inhibitor, MG132, and the levels of GRO-alpha mRNA were analyzed by reverse transcription-polymerase chain reaction or northern blotting. Levels of GRO-alpha protein in the cell-conditioned medium were determined by enzyme-linked immunosorbent assay. MG132 alone increased the levels of GRO-alpha mRNA and protein; however, it did not affect the GRO-alpha mRNA induced by lipopolysaccharide (LPS) and inhibited the LPS-induced decrease in IkappaB levels. Other proteasome inhibitors, MG115 and lactacystin, also induced the expression of GRO-alpha mRNA. MG132 induced the phosphorylation of p38 MAPK, MEK and JNK. Pretreatment of the cells with SB203580, an inhibitor of p38 MAPK, suppressed the MG132-induced GRO-alpha expression, but pretreatment of the cells with U0126, PD98059 or SP600125, inhibitors of MEK1/2 or JNK, did not influence the effect of MG132. We conclude that MG132 upregulates GRO-alpha expression in vascular endothelial cells, at least in part, through the activation of p38 MAPK.

GRO-alpha in normal and pathological thyroid tissues and its regulation in thyroid-derived cells.

Thyroid glands affected by Graves' disease (GD) show striking leukocytic infiltration, mainly by T-cells. The mechanisms by which the various leukocytes are maintained in the thyroid are unknown. Growth-regulated oncogene-alpha (GRO-alpha) in interaction with its receptor CXCR2 is a chemoattractant for both T-cells and neutrophils and may be one of the chemokines involved in the cell maintenance. GRO-alpha and CD18 mRNA as a marker of leukocytic infiltration were quantified in thyroid tissue using competitive RT-PCR. We found very high GRO-alpha mRNA levels in all thyroid tissues. In GD patients (n=16), the GRO-alpha mRNA did not correlate with the CD18 mRNA level or thyroid peroxidase and TSH-receptor antibodies in patients' sera. In thyroid autonomy (n=10), the GRO-alpha mRNA levels were significantly lower in autonomous single adenomas compared with the corresponding normal tissue. In order to define the cellular source of GRO-alpha mRNA and protein, we examined various thyroid-derived cells. Thyrocytes, thyroid-derived leukocytes and fibroblasts showed basal GRO-alpha mRNA and protein expression, which was remarkably upregulated by different stimuli in vitro. The expression of GRO-alpha by thyroid carcinoma cell lines confirms that thyrocytes may actually produce GRO-alpha. As shown by flow cytometry and immunohistology, CD68+ monocytes/macrophages are the only cell population strongly expressing CXCR2 in the thyroid.

Expression and regulation of growth-regulated oncogene alpha in human endometrial stromal cells.

Growth-regulated oncogene alpha (GROalpha), a potent chemoattractant for neutrophils, has previously been detected in the endometrial stromal cells (ESC) of human endometrium. In this study, the mRNA expression of GROalpha in the endometrium was evaluated by reverse transcription-polymerase chain reaction analysis, while the localization of GROalpha protein was studied by immunohistochemistry and the concentrations of GROalpha were measured using an enzyme-linked immunosorbent assay (ELISA). The effects of known modulators of endometrial function on the production of GROalpha by ESC were also examined by ELISA and Northern blot analysis. The expression of both GROalpha mRNA and GROalpha protein was detected in the cycling endometrium. GROalpha protein was localized mainly in the stroma, and endometrial tissues in the secretory phase contained higher amounts of GROalpha protein than did those in the proliferative phase. The production of GROalpha by ESC was enhanced by in-vitro decidualization. Lipopolysaccharide, tumour necrosis factor-alpha and interleukin-1beta also stimulated the expression of GROalpha mRNA and protein by ESC. These results suggest that the production of GROalpha by ESC is regulated by ovarian steroid hormones as well as by inflammatory mediators. The modulation of GROalpha concentrations in the local environment may contribute to normal and pathological processes in the uterus by regulating leukocyte trafficking in the endometrium.

Growth Regulated Oncogene-α expression by murine squamous cell carcinoma promotes tumor growth, metastasis, leukocyte infiltration and angiogenesis by a host CXC Receptor-2 dependent mechanism

Growth Regulated Oncogene-alpha (GRO-alpha) is an autocrine growth factor in melanoma and is a member of the C-X-C family of chemokines which promote chemotaxis of granulocytes and endothelia through binding to CXC Receptor 2. We found previously that variants of murine squamous cell carcinoma PAM 212 which grow and metastasize more rapidly in vivo constitutively express increased levels of murine GRO-alpha, designated mGRO-alpha, or KC. We have examined the possible role of mGRO-alpha expression in malignant progression of squamous cell carcinoma PAM 212 in homologous BALB/c and BALB CXC Receptor-2 deficient mice. Transfection of the PAM 212 cell line which exhibits low expression of GRO-alpha and malignant potential with a pActin-KC vector encoding mGRO-alpha enabled isolation of PAM-KC expressing cell lines. These PAM-KC transfectants displayed an increased rate of growth and metastasis in BALB/c mice, similar to the highly malignant phenotype observed in spontaneously occurring metastatic variants. Furthermore, the PAM-KC tumors showed an increase in infiltration of host leukocytes and CD31+ blood vessels, consistent with increased CXC chemokine activity. The increased growth of PAM-KC cells was attenuated in CXCR-2 deficient mice, indicating that the increased growth was dependent in part upon host cells responsive to the CXC chemokine. Together, these results show that a CXC chemokine such as GRO-alpha can promote malignant growth of murine squamous cell carcinoma by a host CXCR-2 dependent pathway. Oncogene (2000) 19, 3477 - 3486

Mig, GRO alpha and RANTES messenger RNA expression in lining layer, infiltrates and different leucocyte populations of synovial tissue from patients with rheumatoid arthritis, psoriatic arthritis and osteoarthritis.

To investigate lymphocyte and monocyte recruitment-specific chemokine expression in synovial tissues from patients with rheumatoid arthritis (RA), psoriatic arthritis (PA) and osteoarthritis (OA), synovial membranes and cytocentrifuge preparations of 7 RA, 8 PA and 10 OA patients were examined by in situ hybridisation with antisense probes of Mig, GRO alpha and RANTES and by immunohistochemistry. Patients' local disease activity (swelling and tenderness) in order to was graded and histological evaluation was performed compare these data with their chemokine expression profiles. Mig and RANTES hybridisation signals were detected in the synovial lining layer and in cellular infiltrates, whereas GRO alpha expression was localised exclusively in the lining layer of PA and RA. Cytological analysis revealed Mig and GRO alpha mRNA mainly in monocytic cells expressing KIM6, while RANTES mRNA was demonstrated predominantly in lymphocytic cells expressing CD3. In OA synovial membranes, significantly fewer hybridisation signals were present than in RA and PA synovial membranes. Patients with PA and RA had mild to severe local disease activity, whereas OA patients showed only mild disease activity. Histologically, PA and RA inflammatory scores ranged from 1 to 5, while OA synovium was consistently graded 1. Therefore, we conclude that the differential expression of Mig, GRO alpha and RANTES in resident and in inflammatory cells has an important role in regulating leucocyte traffic in inflammatory arthropathies. The diverse leucocyte specificity of Mig, GRO alpha and RANTES may thus regulate the recruitment of different leucocyte populations, as detected in PA and RA. Therefore, the pattern of cellular infiltration in human synovitis and the corresponding clinical signs of inflammation basically reflect the localisation and expression intensity of chemokines, which may be an important target for future disease modulation.

Overexpression of CXC-chemokines and CXC-chemokine receptor type II constitute an autocrine growth mechanism in the epidermoid carcinoma cells KB and A431.

The CXC-chemokines Groalpha and interleukin-8 (IL-8) are well characterized growth factors for melanoma cells. Here the constitutive expression of Groalpha, IL-8 and their receptors (CXCR1 and CXCR2) as well as their functional involvement in the proliferation response were analyzed in normal keratinocytes and epidermoid carcinoma cell lines A431 and KB. Flow cytometric measurements, ELISA and semi-quantitative RT-PCR revealed low constitutive protein secretion and mRNA expression of both CXC-chemokines as well as CXCR1 and 2 in normal keratinocytes, whereas significant higher levels of CXC-chemokines and CXCR2 were deteced in epidermoid carcinoma cells. Proliferation of epidermoid carcinoma cells could be induced by CXC-chemokines and constitutive proliferation could be inhibited by neutralizing antibodies against CXC-chemokines and CXCR2. These studies indicate that constitutive Groalpha, IL-8 and CXCR2 protein expression enable an autocrine growth mechanism in epidermoid carcinoma cells.

Cryptosporidium parvum infection of human intestinal epithelial cells induces the polarized secretion of C-X-C chemokines.

Cryptosporidium parvum infects intestinal epithelial cells and does not invade deeper layers of the intestinal mucosa. Nonetheless, an inflammatory cell infiltrate that consists of neutrophils and mononuclear cells is often present in the lamina propria, which underlies the epithelium. This study investigated the host epithelial cell response to C. parvum by assessing in vitro and in vivo the expression and production of proinflammatory cytokines by intestinal epithelial cells after infection. The human colon epithelial cell lines HCT-8 and Caco-2 and human intestinal xenografts in SCID mice were infected with C. parvum. The expression and secretion of the C-X-C chemokines interleukin-8 (IL-8) and GROalpha were determined by reverse transcription-PCR analysis and enzyme-linked immunosorbent assay. Our results demonstrate that upregulated expression and secretion of IL-8 and GROalpha after C. parvum infection of intestinal epithelial cells first occurred 16 to 24 h after infection and increased over the ensuing 1 to 2 days. The kinetics of C-X-C chemokine production by C. parvum-infected epithelial cells contrast markedly with the rapid but transient expression of C-X-C chemokines by epithelial cells infected with invasive enteric bacteria. C-X-C chemokine secretion in C. parvum-infected epithelial cells occurred predominantly from the basolateral surface in polarized monolayers of Caco-2 cells grown in Transwell cultures, whereas cell lysis occurred at the apical surface. The basolateral secretion of IL-8 and GROalpha from C. parvum-infected epithelial cells suggests that C-X-C chemokines produced by those cells contribute to the mucosal inflammatory cell infiltrate in the underlying intestinal mucosa.

Co-Localized Overexpression of GRO-α and IL-8 mRNA Is Restricted to the Suprapapillary Layers of Psoriatic Lesions

Epidermal infiltration by polymorphonuclear cells is a prominent feature in psoriatic lesions. Expression of neutrophil-specific chemoattractants by lesional keratinocytes could play an important role in the regulation of this infiltration process. We therefore examined the mRNA expression of GRO-alpha, a well-characterized peptide with neutrophil-specific activation profile in psoriatic lesions by in situ hybridization. Clusters of clearly detectable and in some cases highly abundant GRO-alpha hybridization signals could be demonstrated in the differentiated layers of psoriatic epidermis. The signals were clearly associated with keratinocytes, with no nearby neutrophils detectable by microscopic examination. When additional tissue sections of GRO-alpha-expressing lesions were examined with an interleukin-8/neutrophil-activating peptide-8 (IL-8)-specific anti-sense probe, IL-8 expression was detectable and confined to areas also expressing GRO-alpha. Expression of both GRO-alpha and IL-8 is focally upregulated by an as yet unknown mechanism in lesional psoriatic keratinocytes, ultimately leading to neutrophil tissue infiltration. We suggest that the focal expression of GRO-alpha and IL-8 in the epidermal layers above the dermal papillae may be involved in the "squirting papilla" reaction described as a characteristic feature of psoriatic plaque-type lesions.

Constitutive and stimulated MCP-1, GRO alpha, beta, and gamma expression in human airway epithelium and bronchoalveolar macrophages

Constitutive expression of mRNAs for GRO alpha, GRO beta, GRO gamma, and MCP-1, belonging to the chemokine family of 8- to 10-kDa cytokines with chemotactic properties for granulocytes and monocytes, has been identified in freshly isolated human nasal and bronchial epithelium, and in bronchoalveolar macrophages (AM). Expression of GRO alpha, GRO gamma, and MCP-1, but not GRO beta, was found in airway epithelial cells. AM expressed all three GRO genes in addition to MCP-1. On reverse transcription, chemokine mRNAs yielded 0.5-30 cDNA molecules/cell, depending on the chemokine and cell type, as determined by a semiquantitative reverse transcriptase-polymerase chain reaction technique. When chemokine mRNA expression in AM and bronchial epithelium from healthy nonatopic individuals was compared, AM expressed more GRO alpha, but similar levels of GRO gamma, MCP-1, and interleukin-8 (IL-8), as in the bronchial epithelial cells. Modulation of chemokine expression by tumor necrosis factor-alpha (TNF-alpha; 10 ng/ml) or endotoxin [lipopolysaccharide (LPS), 100 ng/ml] exposure was studied in primary nasal epithelial cell and alveolar macrophage cultures. In epithelial cells, LPS did not induce chemokine expression but GRO alpha, IL-8, and MCP-1 were upregulated approximately 100-fold by TNF alpha; GRO gamma expression was elevated only 1.5- to 4-fold. In AM cultures, all three GROs were strongly induced by LPS with peak mRNA expression 24 h after stimulation (approximately 50- to 100-fold increase compared with control cultures). MCP-1 mRNA expression, on the other hand, was not increased by LPS in AM. GRO protein was present in supernatants of stimulated epithelial cells and AM.(ABSTRACT TRUNCATED AT 250 WORDS)