Rat CXC chemokine GRO/CINC-1 paradoxically stimulates the growth of gastric epithelial cells

Sensitive, nonradioactive assay of phosphorylase kinase through measurement of enhanced phosphorylase activity towards fluorogenic dextrin

Glycogen phosphorylase (GP) exists in two interconvertible forms, GPa (phosphorylated form, high activity) and GPb (nonphosphorylated form, low activity). Phosphorylase kinase (PhK) catalyses the phosphorylation of GPb and plays a key role in the cascade system for regulating glycogen metabolism. In this study, we developed a highly sensitive and nonradioactive assay for PhK activity by measuring the enhanced GP activity towards a pyridylaminated maltohexaose. The enhanced GP activity (ΔA) was calculated by the following formula: ΔA = A(+) - A(0), where A(+) and A(0) represent the GP activities of the PhK-treated and PhK-nontreated samples, respectively. Using a high-performance liquid chromatograph equipped with a fluorescence spectrophotometer, the product of GP activity could be isolated and quantified at 10 fmol. This method does not require the use of any radioactive compounds and only 1 µg of GPb per sample was needed to obtain A(+) and A(0) values. The remarkable reduction in GPb concentration enabled us to discuss an interesting new role for glycogen in PhK activity.

Targeted gene silencing using a follicle-stimulating hormone peptide-conjugated nanoparticle system improves its specificity and efficacy in ovarian clear cell carcinoma in vitro

BACKGROUND

RNA interference technology has shown high therapeutic potential for cancer treatment. However, serum instability, poor tissue permeability and non-specific uptake of short interfering RNA (siRNA) limit its administration in vivo. To overcome these limitations and improve the specificity for ovarian cancer, we developed a targeted nanoparticle delivery system for siRNA. This system included follicle-stimulating hormone (FSH) β 33-53 peptide as a targeting moiety that specifically recognized FSH receptor (FSHR) expressed on ovarian cancer cells. Growth regulated oncogene α (gro-α) has been reported to be involved in ovarian cancer development and progression. Thus, siRNA targeted to gro-α was used as an antitumor drug in this delivery system.

METHODS

FSH β 33-53 peptide-conjugated gro-α siRNA-loaded polyethylene glycol (PEG)-polyethylenimine (PEI) nanoparticles (FSH33-G-NP) were prepared and characterized by gel retardation assay and transmission electron microscopy. Particle size and zeta potential were determined. Expression of gro-α mRNA and protein was detected by real-time quantitative RT-PCR, immunocytochemistry and enzyme-linked immunosorbent assay. The proliferation, migration and invasion of the ovarian clear cell carcinoma cell line ES-2 were evaluated by cell counting kit-8 assay, cell scratch assay and transwell migration assay.

RESULTS

A siRNA sequence that is effective in silencing gro-α expression was obtained and loaded into the targeted delivery system. Compared with gro-α siRNA-loaded nanoparticles without FSH peptide modification (G-NP), FSH33-G-NP significantly down-regulated gro-α expression in ES-2 cells at mRNA and protein levels. Consequently, the aggressive biological behaviors of ES-2 cells, including proliferation, migration and invasion, were suppressed after silencing gro-α expression, and the addition of the FSH β 33-53 peptide enhanced the suppressive effects.

CONCLUSIONS

This study indicated that a FSHR-mediated delivery system could mediate the highly selective delivery of siRNA into ovarian cancer cells and that silencing gro-α expression could be a potential choice for ovarian cancer treatment.

Bile acid promotes intestinal metaplasia and gastric carcinogenesis

BACKGROUND

Bile acid and Helicobacter pylori (H. pylori) are important toxic factors for gastric mucosal injury. We examined the role of bile acid in promoting histologic gastritis and gastric carcinoma in Japanese patients.

METHODS

A total of 767 patients (452 men, mean age 51.1 years) were studied. Gastric juice was collected by gastro-endoscopic examination, and the bile acid concentration was examined by enzymatic method. The grade of histologic gastritis was evaluated by gastric biopsies, and the relationship between the bile acid concentration and the gastritis score was examined. The occurrence of gastric cancer was examined by a retrospective cohort study. CDX2/CINC1 expression in RGM-1 cells was evaluated by real-time PCR.

RESULTS

In H. pylori-positive patients, we found significant positive correlation between the bile acid concentration and the grades of atrophy/intestinal metaplasia (P < 0.01). However, we found significant negative associations between the bile acid concentrations and the histologic scores of mononuclear cell/neutrophil infiltrations (P < 0.01). Patients with a high concentration of bile acid developed gastric cancer more frequently than those with a low concentration (P < 0.05). Cholic acid treatment significantly increased CDX2 expression in RGM-1 cells. CINC1 expression in RGM-1 cell was significantly induced by coculture with H. pylori, and the induction was reduced by glycochenodeoxycholic acid treatment.

CONCLUSION

The bile acid in gastric juice contributes to the progression of histologic atrophy and intestinal metaplasia without inflammatory cell infiltration, followed by carcinogenesis in H. pylori-positive patients.

IMPACT

Bile acid promotes intestinal metaplasia and gastric carcinogenesis without inflammatory cell infiltration.

The role of CXCR2 chemokine receptors in the oral squamous cell carcinoma

This study evaluated the relevance of CXCR2 chemokine receptors in oral squamous cell carcinoma, by means of in vitro and in vivo approaches. The in vitro incubation of the selective and non-peptide CXCR2 receptor antagonist N-(2-hydroxy-4-nitrophenyl)-N9-(2-bromophenyl) Urea (SB225002; 25 to 800 nM) produced a time- and concentration-dependent inhibition of SCC158 (rat) and HN30 (human) cell lines viability. Conversely, this antagonist did not significantly affect the viability of the immortalized keratinocyte lineage, HaCaT. Additionally, the incubation of human IL-8 and rat CINC-1 CXCR2 agonists produced a concentration-related increase on HN30 and SCC158 proliferation. The submucosal injection of SCC158 cells (5 × 10(6) cells) into the tongue of Fischer 344 rats induced tumor development, which displayed typical clinical features. Immunohistochemical analysis of rat tongue biopsies revealed a marked increase of CXCR2 receptor immunoreactivity, which was accompanied by augumented expression of VEGF and caspase-3. Our data suggests an important role for CXCR2 receptors in oral squamous cell carcinoma.

Chemokine expression in renal ischemia/reperfusion injury is most profound during the reparative phase

Chemokines are important players in the migration of leukocytes to sites of injury and are also involved in angiogenesis, development and wound healing. In this study, we performed microarray analyses to identify chemokines that play a role during the inflammatory and repair phase after renal ischemia/reperfusion (I/R) injury and investigated the temporal relationship between chemokine expression, leukocyte accumulation and renal damage/repair. C57Bl/6 mice were subjected to unilateral ischemia for 45 min and sacrificed 3 h, 1 day and 7 days after reperfusion. From ischemic and contralateral kidney, RNA was isolated and hybridized to a microarray. Microarray results were validated with quantitative real-time reverse transcription–PCR (QRT–PCR) on RNA from an independent experiment. (Immuno)histochemical analyses were performed to determine renal damage/repair and influx of leukocytes. Twenty out of 114 genes were up-regulated at one or more reperfusion periods. All these genes were up-regulated 7 days after I/R. Up-regulated genes included CC chemokines MCP-1 and TARC, CXC chemokines KC and MIP-2α, chemokine receptors Ccr1 and Cx3cr1 and related genes like matrix metalloproteinases. Microarray data of 1 and 7 days were confirmed for 17 up-regulated genes by QRT–PCR. (Immuno)histochemical analysis showed that the inflammatory and repair phase after renal I/R injury take place after, respectively, 1 and 7 days. Interestingly, chemokine expression was highest during the repair phase. In addition, expression profiles showed a biphasic expression of all up-regulated CXC chemokines coinciding with the early inflammatory and late repair phase. In conclusion, we propose that temporal expression of chemokines is a crucial factor in the regulation of renal I/R injury and repair.

Effect of RANTES promoter genotype on the severity of intestinal metaplasia in Helicobacter pylori-infected Japanese subjects

BACKGROUND

A complex interaction of host genetic and environmental factors may be relevant in the development of Helicobacter pylori (H. pylori)-related gastro-duodenal diseases. RANTES is a potent chemoattractant peptide for memory T lymphocytes and eosinophils, and has been shown to be enhanced in H. pylori-infected gastric mucosa. We aimed to clarify the effect of RANTES functional promoter polymorphism on the risk of gastro-duodenal diseases in a Japanese population.

METHODS

Four hundred and eighty-three subjects, comprising 106 gastric ulcer, 52 duodenal ulcer, and 325 non-ulcer subjects, were included in this study. Restriction fragment length polymorphism (RFLP) analysis was performed for polymorphisms at -28 C/G in the RANTES gene promoter region. Gastritis scores of antral gastric mucosa were assessed according to the updated Sydney system.

RESULTS

There were no significant differences in the RANTES promoter genotype distributions among non-ulcer subjects, ulcer patients, and gastric and duodenal ulcers. However, the degree of intestinal metaplasia was significantly lower among G carriers in H. pylori-infected subjects aged 60 years or older (C/C vs. G carriers; 1.28 +/- 1.02 vs. 0.83 +/- 0.89, P = 0.0357). In addition, we also found that the same genotype held a lower risk of more severe intestinal metaplasia in H. pylori-infected female subjects (C/C vs. G carriers; 0.91 +/- 1.03 vs. 0.41 +/- 0.73, P = 0.0443).

CONCLUSION

The polymorphism of RANTES promoter is not associated with the susceptibility to peptic ulcer diseases, but the -28 G carrier is associated with a reduced risk of developing more severe intestinal metaplasia in H. pylori-positive subjects aged 60 years and older and in female subjects.

Macrophage-Inflammatory Protein-3α Mediates Epidermal Growth Factor Receptor Transactivation and ERK1/2 MAPK Signaling in Caco-2 Colonic Epithelial Cells via Metalloproteinase-Dependent Release of Amphiregulin

Previously, we reported that normal colonocytes produce the memory CD4(+) T cell-directed chemokine MIP-3alpha, and that epithelial MIP-3alpha levels are elevated in inflammatory bowel disease. Interestingly, the unique receptor for MIP-3alpha, CCR6, is expressed by a variety of cell types including colonocytes, suggesting that MIP-3alpha may regulate additional biological activities in the intestine. The aim of this study was to determine whether MIP-3alpha can induce intestinal epithelial cell proliferation and to examine the signaling mechanisms that mediate this response. We show that nonstimulated Caco-2 and HT-29 colonic epithelial cells express CCR6, and that stimulation of Caco-2 cells by MIP-3alpha can dose dependently increase cell proliferation as well as activate the epidermal growth factor receptor (EGFR) and ERK1/2 MAPK. MIP-3alpha-mediated ERK1/2 activation in Caco-2 cells appeared to require metalloproteinase-dependent release of the endogenous EGFR ligand amphiregulin and transactivation of the EGFR. Moreover, blockade of amphiregulin bioactivity using a neutralizing polyclonal Ab significantly reduced MIP-3alpha-mediated, but not EGF-mediated Caco-2 cell proliferation. Taken together, our findings indicate that MIP-3alpha can regulate mitogenic signaling in colonic epithelial cells and thus may serve an important homeostatic function in the intestine by regulating tissue turnover and maintenance of the epithelium, in addition to its role in regulating leukocyte recruitment.

Rat strains differ in susceptibility to Ureaplasma parvum-induced urinary tract infection and struvite stone formation

Individuals with struvite uroliths are susceptible to recurrent urinary tract infections (UTI), sepsis, and renal disease. Unfortunately, little is known about the host-specific factors that predispose to this disease. In order to develop a rodent model that can address this problem, we inoculated female Fischer 344 (F344), Lewis (LEW), Sprague-Dawley (SD), and Wistar (WIS) rats with a host-adapted strain of Ureaplasma parvum. Animals were necropsied at 2 weeks postinoculation; 100% of F344, 42% of SD, 10% of LEW, and 10% of WIS rats remained infected. Severe bladder lesions and struvite calculi were seen in 64% of F344 rats; in other rat strains, bladder lesions were mild or absent. F344 rats with struvite uroliths had the highest urinary levels of proinflammatory cytokines, such as GRO/KC, interleukin-1alpha (IL-1alpha), and IL-1beta. F344 rats without struvite stones at necropsy had milder bladder lesions and significantly lower urinary levels of proinflammatory cytokines but a more prominent inflammatory response than did other rat strains. Based on our results, struvite stone formation is linked to a robust inflammatory response that does not resolve UTI but instead promotes damage to surrounding tissues.

The chemokine KC regulates HGF-stimulated epithelial cell morphogenesis

Hepatocyte growth factor (HGF) induces migration, proliferation, and branching in renal epithelial cells from the inner medullary collecting duct (mIMCD-3 cells). Microarray analysis after HGF stimulation of these cells revealed upregulation of the chemokine KC. We found that both the message and protein levels of KC are increased after HGF treatment and that mIMCD-3 cells express the KC receptor CXCR2. Treatment with KC results in stimulation of mIMCD-3 cell proliferation but has no effect on basal rates of cell migration or branching morphogenesis. In contrast to its known stimulatory effect on neutrophil migration, KC markedly inhibits HGF-mediated cell migration and branching morphogenesis, resulting in shorter tubules with fewer branch points. Examination of the mechanism of this effect reveals that KC does not alter phosphorylation of the c-met receptor or the initial activation of the MAPK or phosphoinositide 3-kinase (PI 3-K) signaling pathways. However, sustained activation of the PI 3-K pathway by HGF was inhibited by treatment with KC, and mimicking this effect by treatment with LY-294002 2 h after HGF stimulation reproduced the inhibition of HGF-stimulated branching morphogenesis. These data demonstrate that HGF-mediated KC production can act in an autocrine fashion to downregulate excessive branching and migration of renal epithelial cells in response to HGF, while still supporting cell proliferation. These characteristics may play a role in modulating the response to HGF during developmental tubule formation and/or during the repair of the tubular architecture following injury.

In vivo proteomic analysis of cytokine expression in laser capture-microdissected urothelial cells of obstructed ureteropelvic junction procured by laparoscopic dismembered pyeloplasty

BACKGROUND AND PURPOSE

Ureteropelvic junction obstruction (UPJO) is defined as an impediment to urinary flow from the renal pelvis into the ureter. The exact cause remains an enigma despite investigations along embryologic, anatomic, and histologic lines. Our goal was to investigate in vivo the expression profile of cytokines in hyperplastic urothelial cells as a means of determining the source of UPJO.

MATERIALS AND METHODS

Cellular proteomes of matched normal and hyperplastic urothelial cells were analyzed by laser capture microdissection (LCM) and tissue microdissection and human cytokine proteomic chips. All specimens (N = 9) were surgically obtained from patients undergoing laparoscopic dismembered pyeloplasty and were immediately embedded in O.C.T. solution and flash-frozen in liquid nitrogen. Tissue sections (6 microm) were mounted on uncoated glass slides using a cryostat, fixed in 70% ethanol, stained with hematoxylin and eosin, and sequentially dehydrated in ethanol and xylene. Typically, paired samples of normal and hyperplastic urothelial cells were procured on separate caps from serial sections of each specimen by the Arcturus PixCell II LCM system using 3000 laser pulses and a spot diameter of 30 microm. Total proteins were harvested and quantitated. Differential expression profile analysis of 43 cytokines in normal and hyperplastic cells were performed using human protein chips. Briefly, the membranes were initially probed with protein (150 ng) from normal or hyperplastic cells and sequentially reacted with a cocktail of biotinylated cytokine antibodies and horseradish peroxidase-conjugated streptavidin. The membranes were developed using enhanced chemiluminescence and analyzed by densitometry.

RESULTS

Comparative densitometric analysis revealed twofold to fourfold upregulation of growth-related oncogene alpha (GRO-alpha), interleukin (IL)-1alpha, interferon (INF)-gamma, IL-8, tumor necrosis factor (TNF)-alpha, RANTES, and macrophage inflammatory protein-1beta (MIP-1beta) and twofold to fourfold downregulation of transforming growth factor (TGF)-beta and IL-10 in hyperplastic urothelial cells compared with paired control cells.

CONCLUSIONS

We here report the efficient application of LCM and proteomic array chips for expression profile analysis of cytokines in vivo. Because the etiology and pathogenesis of UPJO are still fragmentary, the marked heterogeneity of the observed cytokine alterations reported here may be of significance. Further studies are required to elucidate the functional significance of the differentially expressed cytokines in the pathogenesis of the disease.

Growth-related oncogene alpha induction of apoptosis in osteoarthritis chondrocytes

OBJECTIVE

To evaluate the apoptotic effect of the chemokine growth-related oncogene alpha (GROalpha), which we recently reported to be up-regulated in osteoarthritis (OA) chondrocytes. Chondrocyte apoptosis is considered to be a major determinant of cartilage damage in OA, a disease resulting from the aberrant production of inflammatory mediators (cytokines and chemokines) and effectors (matrix metalloproteinases and reactive oxygen and nitrogen species) by chondrocytes.

METHODS

We investigated the apoptotic effect of GROalpha on isolated human cells and on in vitro-cultured cartilage explants by conventional methods (morphology, detection of DNA fragmentation in situ and in solution, exposure of phosphatidylserine) and by analysis of "early" biochemical events (plasma membrane depolarization, activation of caspase 3, and phosphorylation of c-Jun N-terminal kinase/stress-activated protein kinase).

RESULTS

We clearly demonstrated that GROalpha was able to initiate a series of morphologic, biochemical, and molecular changes that led to chondrocyte apoptosis. Moreover, we found that additional signals delivered from the extracellular matrix (ECM) were essential in the control of chondrocyte susceptibility to GROalpha-induced apoptosis, since cell death was detected only when cells were stimulated after reestablishment of their proper interactions with the ECM, or in cartilage explant samples with reduced ECM, as indicated by decreased Safranin O staining.

CONCLUSION

GROalpha can induce apoptosis in articular chondrocytes, and the induction is dependent upon additional signals from the ECM. These findings are relevant to understanding the pathogenesis of OA, in view of the availability of the GROalpha chemokine in the joint space in the course of this rheumatic disease.

Effect of interlukin-1beta on proliferation of gastric epithelial cells in culture

BACKGROUND

Helicobacter pylori is the main risk factor for the development of non-cardia gastric cancer. Increased proliferation of the gastric mucosa is a feature of H. pylori infection. Mucosal interkeukin-1beta production is increased in H. pylori infection and IL-1beta genotypes associated with increased pro-inflammatory activity are risk factors for the development of gastric cancer. The effect of IL-1beta on gastric epithelial cell proliferation has been examined in this study.

METHODS

AGS cells were cultured with IL-1beta. DNA synthesis was assed by [3H]thymidine incorporation and total viable cell numbers by MTT assay.

RESULTS

IL-1beta dose dependently increased DNA synthesis and cell numbers. The enhanced proliferation was blocked by interleukin-1 receptor antagonist. Addition of neutralising antibody to GM-CSF reduced IL-1beta-stimulated proliferation by 31 +/- 4 %. GM-CSF alone significantly stimulated proliferation. Addition or neutralisation of IL-8 had no effect on basal or IL-1beta-stimulated proliferation. The tyrosine kinase inhibitor genistein completely blocked IL-1beta-stimulated proliferation and inhibition of the extracellular signal related kinase pathway with PD 98059 inhibited IL-1beta stimulated proliferation by 58 +/- 5 %.

CONCLUSIONS

IL-1beta stimulates proliferation in gastric epithelial cells. Autocrine stimulation by GM-CSF contributes to this proliferative response. Signalling via tyrosine kinase activity is essential to the mitogenic response to IL-1beta. The extracellular signal related kinase pathway is involved in, but not essential to downstream signalling. IL-1beta may contribute to the hyperproliferation seen in H. pylori- infected gastric mucosa, and be involved in the carcinogenic process.

Developmental expression of two CXC chemokines, MIP-2 and KC, and their receptors

CXC chemokines, macrophage inflammatory protein-2 (MIP-2) and KC, (a cloning designation based on ordinate and abscissa position) as well as the CXC chemokine receptor, CXCR2, are expressed in a variety of cells and tissues in adult mice. Targeted deletion of the gene encoding murine CXCR2 does not result in obvious changes in the development of the organ system of the mouse, though the CXCR2-/- mouse is compromised with regard to its ability to resist infection, heal wounds, and maintain homeostasis when challenged with microbes and/or chemicals. In an attempt to develop insight into additional possible subtle roles of CXCR2 and its ligands in the development of the mouse, we examined the expression of MIP-2, KC, CXCR2, as well as the Duffy antigen binding protein for chemokines during embryonic (p.c.) days 11.5 through 14.5 in the mouse. We observed strong correlation between the expression of MIP-2 and CXCR2 in the developing brain, cardiovascular system and condensing mesenchyme between 11.5 and 13.5 days. Moreover, the expression of KC was parallel to the expression of the Duffy antigen binding protein for chemokines with regard to temporal pattern and tissue localization. MIP-2 and CXCR2 are highly expressed in the brain, first in the cerebellum and in the head mesenchyme, the meninges and the floor plate, and by 14.5 days are also present in the telencephalon, thalamus and hypothalamus. In the developing brain KC and Duffy were prominently expressed in the neuronal tracts, the forebrain, sympathetic ganglia, and along the periphery of the neural tube. However, KC and Duffy were less prevalent in the developing cardiovascular system, lung and other organs, muscle and bone, than are CXCR2 and MIP-2. These data suggest that the roles for these chemokines and their receptors during development may be more significant than was initially thought based upon the phenotype of the mice with targeted deletion of CXCR2 and Duffy.

Role of apoptosis in Helicobacter pylori-associated gastric mucosal injury

Apoptosis, a programmed cell death, was ignored, just like Helicobacter pylori, only to reappear recently. However, the number of current publications dealing with apoptosis or H. pylori has increased exponentially. Although gastric epithelial apoptosis is a programmed physiological event in the superficial aspect of the mucosa and is important for healthy cell turnover, H. pylori infection reportedly promotes such a cell death sequence. Because apoptosis regulates the cycle of cell turnover in balance with proliferation, dysregulation of apoptosis or proliferation evoked by H. pylori colonization would be linked to the gastric carcinogenesis. In other words, a reduced level of apoptosis could contribute to the generation of gastric cancer. Herein, we review apoptosis as well as its associated pathological events, such as hyperproliferation, in H. pylori-colonized gastric mucosa.