High-temperature-required protein A2 as a predictive marker for response to chemotherapy and prognosis in patients with high-grade serous ovarian cancers.

BACKGROUND: High-temperature-required protein A2 (HtrA2), a protein relating with apoptosis in a caspases-dependent and non-dependent manner, has been reported to be associated with chemosensitivity in several human cancers. METHODS: Tissue microarrays made from 142 patients with high-grade serous ovarian adenocarcinoma were evaluated to assess whether HtrA2 expression was related with several clinical parameters. RESULTS: Negative HtrA2 expression was observed in 36 cases (25%) of the patients, and related with significantly lower response rates of primary chemotherapy than those with positive HtrA2 expression (56% vs 83%, P<0.01). In addition, negative HtrA2 expression was identified as an independent worse prognostic factor for progression-free survival and overall survival by multivariate analyses. Furthermore, HtrA2 downregulation modulated sensitivity to platinum in serous ovarian cancer cells in vitro. CONCLUSIONS: HtrA2 expression was a predictor for sensitivity to chemotherapy, and could be a candidate of molecular target in the treatment of high-grade serous ovarian cancers.

The human antimicrobial peptide dermcidin activates normal human keratinocytes.

BACKGROUND: The skin has evolved an epithelial defence mechanism which is characterized by antimicrobial peptides that inactivate various microorganisms and exhibit stimulatory activities bridging innate and adaptive immunity. Dermcidin (DCD) is a newly isolated antimicrobial peptide produced by the eccrine sweat glands in the skin. Recently, the DCD peptides DCD-1 and DCD-1L have been shown to display in vitro microbicidal activities against bacteria and viruses. OBJECTIVES: Because some skin-derived antimicrobial peptides activate keratinocytes, we investigated whether DCD-1L would also trigger keratinocyte activation. METHODS: Normal human keratinocytes were used in this study. The ability of DCD-1L to induce the production of cytokines/chemokines by keratinocytes was determined by enzyme-linked immunosorbent assay, and various inhibitors were used to investigate the stimulatory mechanism of DCD-1L. Mitogen-activated protein kinase (MAPK) phosphorylation and NF-kappaB activation were analysed by Western blotting. RESULTS: DCD-1L stimulated keratinocytes to generate cytokines and chemokines including tumour necrosis factor-alpha, interleukin-8 (CXCL8), interferon-inducible protein 10 (CXCL10) and macrophage inflammatory protein-3alpha (CCL20). To determine the molecular mechanism involved, we showed that DCD-1L-mediated cytokine/chemokine production was controlled by both G-protein and MAPK pathways, as evidenced by the inhibitory effects of pertussis toxin and specific inhibitors for p38 and ERK, but not for JNK, on DCD-1L-induced keratinocyte activation. Furthermore, we confirmed that DCD-1L could induce phosphorylation of p38 and ERK, and noticeably upregulated NF-kappaB activation. CONCLUSIONS: Taken together, the new activity of DCD-1L to stimulate the production of cytokines/chemokines by keratinocytes provides novel evidence for the implication of DCD, beyond its microbicidal ability, in skin immunity.

Circulating micrometastases of esophageal cancer detected by carcinoembryonic antigen mRNA reverse transcriptase-polymerase chain reaction: clinical implications.

In some patients without distant metastases according to conventional preoperative investigations, relapse occurs in distant organs within a few years after radical resection of esophageal cancer. Various attempts have been made to detect micrometastases that are not found by conventional techniques. A quantitative real-time reverse-transcriptase polymerase chain reaction was used to detect messenger RNA for carcinoembryonic antigen in 147 blood samples from 49 patients scheduled for radical resection of esophageal cancer at Juntendo University Hospital between September 2003 and June 2004. The number of circulating cancer cells was assessed and the clinical significance of detecting such micrometastases was analyzed. Multivariate analysis showed that positivity of this assay was significantly associated with pT1 or pT2 disease and stage III or stage IV disease. Patients with more than 40-50 carcinoembryonic antigen mRNA copies among 10(4) normal cells on quantitative analysis had a higher recurrence rate. The number of tumor cells circulating in the blood may have more influence on the prognosis of esophageal cancer than the presence of tumor cells.

Evaluation of the suppressive actions of glucosamine on the interleukin-1beta-mediated activation of synoviocytes.

OBJECTIVE: Recently, we found that administration of glucosamine to adjuvant arthritis, a model for rheumatoid arthritis, suppressed the progression of arthritis in rats. To clarify its anti-inflammatory mechanism, we evaluated the actions of glucosamine on the activation of synoviocytes in vitro. MATERIALS AND METHODS: Synoviocytes isolated from human synovial tissues were stimulated with interleukin (IL)-1beta in the presence of 0.01-1 mM glucosamine. IL-8 and prostaglandin (PG) E(2) were measured by ELISA, and nitric oxide was quantitated by Griess assay. IL-8 mRNA was detected by RT-PCR. Furthermore, the effect of glucosamine on the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and the binding of [(125)I] IL-1beta to its receptors were examined using a primary human synovial cell line (CSABI- 479). RESULTS: Glucosamine significantly suppressed the IL-1beta-induced IL-8 production as well as its mRNA expression (p < 0.05) at 1 mM. Furthermore, glucosamine (1 mM) inhibited the IL-1beta-induced nitric oxide and PGE(2) production (p < 0.05). Moreover, glucosamine suppressed the IL-1beta-induced phosphorylation of p38 MAPK (p < 0.05 at >0.1 mM) and the IL-1beta-binding to its receptors (p < 0.05 at 1 mM). CONCLUSIONS: These observations suggest that glucosamine can suppress the IL-1beta-mediated activation of synoviocytes (such as IL-8-, nitric oxide- and PGE(2)-production, and phosphorylation of p38 MAPK), thereby possibly exhibiting antiinflammatory actions in arthritis.

Cathelicidin LL-37 induces the generation of reactive oxygen species and release of human alpha-defensins from neutrophils.

BACKGROUND: Psoriasis is characterized by epidermal infiltration of neutrophils that destroy invading microorganisms via a potent antimicrobial arsenal of oxidants and antimicrobial agents. In contrast to atopic dermatitis, psoriasis exhibits low levels of skin infections due to the presence of antimicrobial agents, including cathelicidin LL-37. LL-37 kills a broad spectrum of microbes, and activates neutrophil chemotaxis. OBJECTIVE: To determine whether or not LL-37 could regulate additional neutrophil functions such as production of cytokines/chemokines, reactive oxygen species and release of neutrophil antimicrobial peptides. METHODS: Human peripheral blood neutrophils were used in this study. The production of interleukin (IL)-8 and release of alpha-defensins were analysed by enzyme-linked immunosorbent assay, and real-time polymerase chain reaction (PCR) was used to quantify alpha-defensin gene expression. Phosphorylation of mitogen-activated protein kinase (MAPK) was determined by Western blotting. The generation of reactive oxygen species was examined using flow cytometry, and intracellular Ca(2+) mobilization was measured using a calcium assay kit. RESULTS: LL-37 enhanced the production of IL-8 under the control of MAPK p38 and extracellular signal regulated kinase (ERK), as evidenced by the inhibitory effects of p38 and ERK1/2 inhibitors on LL-37-mediated IL-8 production. Furthermore, LL-37 induced phosphorylation of p38 and ERK. We also revealed that LL-37 stimulated the generation of reactive oxygen species dose- and time-dependently, most probably via NADPH oxidase activation and intracellular Ca(2+) mobilization. Finally, LL-37 induced both mRNA expression and protein release of alpha-defensins, known as human neutrophil peptide 1-3. CONCLUSION: Taken together, we suggest that in addition to its microbicidal properties, LL-37 may contribute to innate immunity by enhancing neutrophil host defence functions at inflammation and/or infection sites.

Novel role of HDAC inhibitors in AML1/ETO AML cells: activation of apoptosis and phagocytosis through induction of annexin A1.

The chimeric fusion protein AML1-ETO, created by the t(8;21) translocation, recruits histone deacetylase (HDAC) to AML1-dependent promoters, resulting in transcriptional repression of the target genes. We analyzed the transcriptional changes in t(8;21) Kasumi-1 AML cells in response to the HDAC inhibitors, depsipeptide (FK228) and suberoylanilide hydroxamic acid (SAHA), which induced marked growth inhibition and apoptosis. Using cDNA array, annexin A1 (ANXA1) was identified as one of the FK228-induced genes. Induction of ANXA1 mRNA was associated with histone acetylation in ANXA1 promoter and reversal of the HDAC-dependent suppression of C/EBPalpha by AML1-ETO with direct recruitment of C/EBPalpha to ANXA1 promoter. This led to increase in the N-terminal cleaved isoform of ANXA1 protein and accumulation of ANXA1 on cell membrane. Neutralization with anti-ANXA1 antibody or gene silencing with ANXA1 siRNA inhibited FK228-induced apoptosis, suggesting that the upregulation of endogenous ANXA1 promotes cell death. FK228-induced ANXA1 expression was associated with massive increase in cell attachment and engulfment of Kasumi-1 cells by human THP-1-derived macrophages, which was completely abrogated with ANXA1 knockdown via siRNA transfection or ANXA1 neutralization. These findings identify a novel mechanism of action of HDAC inhibitors, which induce the expression and externalization of ANXA1 in leukemic cells, which in turn mediates the phagocytic clearance of apoptotic cells by macrophages.

Preventive actions of a high dose of glucosamine on adjuvant arthritis in rats.

OBJECTIVE: Glucosamine, a naturally occurring amino monosaccharide has been used to treat or prevent osteoarthritis in humans. In this study, we evaluated the effect of glucosamine on rat adjuvant arthritis, a model of rheumatoid arthritis. MATERIALS AND METHODS: Adjuvant arthritis was induced in male Wistar rats by injection of Freund's complete adjuvant (FCA) into the right hind paw, and 300 mg/kg of glucosamine, an extra-dose compared with a regular dose for osteoarthritis patients (1.5 g/day, approximately 25 mg/kg), was orally administered once a day to the arthritic rats for 22 days. RESULTS: Glucosamine significantly suppressed the increase in arthritis score (p < 0.05) after day 10 of adjuvant injection, and inhibited the swelling of FCA-injected right and -uninjected left hind paws (p < 0.01) after day 18. In addition, histopathological examination of the arthritic joints revealed that glucosamine suppressed synovial hyperplasia, cartilage destruction and inflammatory cell infiltration. Furthermore, glucosamine reduced the production of nitric oxide and prostaglandin E(2) in plasma (p < 0.05). CONCLUSIONS: These observations suggest that glucosamine is able to suppress the progression of adjuvant arthritis in rats. Glucosamine may be expected as a novel anti-inflammatory agent for treatment of rheumatoid arthritis.

Augmentation of the bactericidal activities of human cathelicidin CAP18/LL-37-derived antimicrobial peptides by amino acid substitutions.

OBJECTIVE: Mammalian myeloid and epithelial cells express various peptide antibiotics (such as defensins and cathelicidins) that contribute to the innate host defense against invading micro-organisms. Among these, human cathelicidin CAP18/LL-37 (L1-S37) possesses potent antibacterial activities against Gram-positive and Gram-negative bacteria. In this study, to develop peptide derivatives with improved bactericidal actions, we utilized the amphipathic 18-mer peptide (K15-V32) of LL-37 as a template, and evaluated the activities of modified peptides. METHODS: Antibacterial activities of the peptides (0.022 approximately 4.4 microM corresponding to 0.1 approximately 10 microg/ml) were assessed by alamarBlue assay using Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Escherichia coli and Pseudomonas aeruginosa as target organisms. Furthermore, the membrane-permeabilization activities of the peptides were examined by using E. coli ML-35p as a target. RESULTS: By substituting E16 and K25 with two L residues, the hydrophobicity of the peptide (18-mer LL) was increased, and by further substituting Q22, D26 and N30 with three K residues, the cationicity of the peptide (18-mer LLKKK) was enhanced. Among peptide derivatives, 18-mer LLKKK exhibited the most potent antibacterial actions against S. aureus (methicillin-resistant and -sensitive), S. pneumoniae, S. pyogenes, E. coli and P. aeruginosa, and possessed the most powerful membrane-permeabilizing activities against E. coli ML-35p at the effective concentrations (p <0.05, 18-mer LLKKK vs. 18-mer LL, 18-mer K15-V32 and LL-37). CONCLUSIONS: Bactericidal activities of the amphipathic human CAP18/LL-37-derived 18-mer peptide can be augmented by modifying its hydrophobicity and cationicity, and 18-mer LLKKK is the most potent among peptide derivatives with therapeutic potential for Gram-positive and Gram-negative bacterial infections.

Inhibitory action of glucosamine on platelet activation in guinea pigs.

OBJECTIVE: Glucosamine, a naturally occurring amino monosaccharide, has been used to treat or prevent osteoarthritis in humans. Recently, we have revealed that glucosamine inhibits platelet activation in vitro. However, the effect of in vivo administration of glucosamine has not yet been clarified. In this study, we administered glucosamine orally to guinea pigs and examined its effects on platelet functions. MATERIALS AND METHODS: Glucosamine hydrochloride solution (0.5%, 5 mg/ml) was administered orally to guinea pigs ad libitum for 22 days, and platelet rich plasma was collected to evaluate platelet functions in vitro. Guinea pigs received an average of 400 mg glucosamine/animal/day. RESULTS: Glucosamine-administration suppressed platelet aggregation in response to ADP by 51% (p < 0.01), but not platelet aggregation induced by collagen. Furthermore, glucosamine-administration inhibited the ADP-induced extracellular release of ATP and production of thromboxane A(2) by 91% and 96%, respectively (p < 0.001). In contrast, glucosamine did not affect the body-weights, platelet counts and bleeding time in guinea pigs after the administration. CONCLUSIONS: These observations suggest that glucosamine is likely to exert an inhibitory action on platelets in vivo by suppressing platelet aggregation, ATP release, and thromboxane A(2) production. Thus, glucosamine could be expected as a novel and safe anti-platelet agent.

Antibacterial cathelicidin peptide CAP11 inhibits the lipopolysaccharide (LPS)-induced suppression of neutrophil apoptosis by blocking the binding of LPS to target cells.

OBJECTIVE: The action of antibacterial cathelicidin CAP11 (cationic antibacterial polypeptide of 11 kDa) on the lipopolysaccharide (LPS)-induced suppression of neutrophil apoptosis was evaluated in vitro. METHODS: Human neutrophils (10(6) cells/ml) were incubated alone or with mononuclear cells (6 x 10(5) cells/ml) in the presence of LPS (10 ng/ml) and CAP 11 (0.1 approximately 10 microg/ml), and neutrophil apoptosis was determined. RESULTS: LPS suppressed neutrophil apoptosis, accompanied with the activation of NF-kappaB, phosphorylation of extracellular signal-related protein kinase (ERK), expression of Bcl-XL (an anti-apoptotic protein) and inhibition of caspase 3 activity. Interestingly, CAP11 (> 1 microg/ml) reversed the actions of LPS to trigger these changes, and induced neutrophil apoptosis (p < 0.0001). Moreover, neutralizing antibodies against Mac-1 (CD11b/CD18) and Toll-like receptor (TLR) 4 completely blocked the LPS-induced suppression of neutrophil apoptosis (p < 0.0001), suggesting a major role of Mac-1 and TLR4 in the LPS-mediated neutrophil activation. In addition, LPS activated monocytes to produce proinflammatory cytokines (IL-1beta, TNF-alpha and IL-8) and inhibited neutrophil apoptosis. Importantly, CAP11 (> 1 microg/ml) reduced the cytokine production, thereby inducing neutrophil apoptosis (p < 0.0001). Finally, CAP11 (> 1 microg/ml) strongly suppressed the LPS-binding to neutrophils and monocytes (p < 0.01). CONCLUSIONS: CAP11 is able to block the LPS-induced survival of neutrophils via the suppression of anti-apoptotic signaling in neutrophils and cytokine production from monocytes by inhibiting the binding of LPS to target cells.

Glucosamine, a naturally occurring amino monosaccharide, suppresses the ADP-mediated platelet activation in humans.

OBJECTIVE: To evaluate the anti-thrombotic action of glucosamine, a naturally occurring amino monosaccharide, platelets were stimulated with ADP in the presence of glucosamine, and its effects on platelet functions were examined. MATERIALS AND METHODS: Human platelet-rich plasma was stimulated with 2.5 microM ADP in the presence of glucosamine (0.01 approximately 1 mM) or other aminosugars (N-acetyl-glucosamine, galactosamine or N-acetyl-galactosamine, 1 mM), and platelet aggregation was monitored. Furthermore, the effects of glucosamine on the thromboxane A2 production, release of granule contents, intracellular calcium mobilization and phosphorylation of Syk (a 72 kD protein tyrosine kinase) were evaluated following ADP-stimulation. In addition, the binding of [3H] ADP to its receptors was examined. RESULTS: Glucosamine (>0.01 mM) dose-dependently suppressed platelet aggregation in response to ADP (p < 0.05), whereas N-acetyl-glucosamine, galactosamine or N-acetyl-galactosamine (1 mM) did not affect the ADP-induced platelet aggregation. Furthermore, glucosamine (>0.1 mM) inhibited the extracellular release of granule contents (ATP and platelet factor 4) and production of thromboxane A2 from ADP-stimulated platelets (p < 0.05). Moreover, glucosamine significantly repressed the intracellular calcium mobilization at >0.1 mM and phosphorylation of Syk at >0.01 mM upon ADP-stimulation (p < 0.05). In addition, glucosamine (>0.1 mM) inhibited the binding of ADP to its receptors (p < 0.05). CONCLUSION: Glucosamine is able to suppress platelet aggregation, release of granule constituents, thromboxane A2 production, calcium mobilization and phosphorylation of Syk possibly via the inhibition of ADP-binding to the receptors. Glucosamine could be expected as a novel anti-platelet agent for thrombotic disorders due to its suppressive actions on platelets.

VEGF regulates the proliferation of acid-exposed alveolar lining epithelial cells.

BACKGROUND: Acid induced pneumonitis resulting in acute respiratory distress syndrome (ARDS) is characterised by increased alveolar permeability and accumulation of neutrophils. It is hypothesised that vascular endothelial growth factor (VEGF) is involved in the development of lung oedema. Furthermore, lower levels of VEGF are detected in bronchoalveolar lavage fluid from patients with ARDS than from non-ARDS patients. We hypothesised that VEGF acts cytoprotectively and have investigated this possibility in vitro with A549 cells. METHODS: A549 cells were incubated in 24 well culture dishes 24 hours before exposure to acid, then incubated with serum free medium containing various concentrations of HCl for 30 minutes at 37 degrees C in 5% CO(2). The acidified medium was changed to normal complete medium; at specified incubation periods the supernatants were collected and the VEGF concentration measured and the number of adherent cells counted. RESULTS: Proliferation of A549 cells and VEGF production were suppressed for at least 48 hours in HCl at a concentration of 50 mM. Restoration of cellular proliferation occurred following exogenous administration of VEGF (concentration of 1-250 ng/ml) and was inhibited by co-incubation with neutralising anti-VEGF antibody, indicating an interaction between VEGF molecules and A549 cells. Control cells were not influenced by administration of exogenous VEGF or anti-VEGF antibody. Treatment with neutralising anti-VEGF receptor (VEGFR) antibodies against VEGFR-1 and VEGFR-2 suppressed proliferation of acid exposed A549 cells but had no effect on control cells. CONCLUSIONS: Exogenous VEGF interacts with VEGFR-1 and VEGFR-2 on the surface and regulates the proliferation of injured alveolar lining epithelial cells in an autocrine or paracrine fashion.

Cathelicidin family of antibacterial peptides CAP18 and CAP11 inhibit the expression of TNF-alpha by blocking the binding of LPS to CD14(+) cells.

Mammalian myeloid and epithelial cells express several kinds of antibacterial peptides (alpha-/beta-defensins and cathelicidins) that contribute to the innate host defense by killing invading micro-organisms. In this study we evaluated the LPS-neutralizing activities of cathelicidin peptides human CAP18 (cationic antibacterial proteins of 18 kDa) and guinea pig CAP11 using the CD14(+) murine macrophage cell line RAW264.7 and the murine endotoxin shock model. Flow cytometric analysis revealed that CAP18 and CAP11 inhibited the binding of FITC-conjugated LPS to RAW264.7 cells. Likewise, Northern and Western blot analyses indicated that CAP18 and CAP11 suppressed LPS-induced TNF-alpha mRNA and protein expression by RAW264.7 cells. Interestingly, CAP18 and CAP11 possessed LPS-binding activities, and they strongly suppressed the interaction of LPS with LPS binding protein that mediates the transport of LPS to CD14 to facilitate the activation of CD14(+) cells by LPS. Moreover, when CAP18 and CAP11 were preincubated with RAW264.7 cells, they bound to the cell surface CD14 and inhibited the binding of FITC-LPS to the cells. Furthermore, in the murine endotoxin shock model, CAP18 or CAP11 administration inhibited the binding of LPS to CD14(+) cells (peritoneal macrophages) and suppressed LPS-induced TNF-alpha expression by these cells. Together these observations indicate that cathelicidin peptides CAP18 and CAP11 probably exert protective actions against endotoxin shock by blocking the binding of LPS to CD14(+) cells, thereby suppressing the production of cytokines by these cells via their potent binding activities for LPS and CD14.

Involvement of cytosolic prolyl endopeptidase in degradation of p40-phox splice variant protein in myeloid cells.

Our previous studies indicated that an alternatively spliced variant mRNA of p40-phox, a cytosolic component of NADPH oxidase, is expressed but its protein is hardly detected in myeloid cells such as promyelocytic HL-60 cells and neutrophils. Here, we have examined the stability of p40-phox variant protein in undifferentiated HL-60 cells. When in vitro-translated proteins were incubated with subcellular fractions of HL-60 cells, p40-phox variant protein but not native p40-phox was degraded by the cytosol and granule fractions. The degradation of variant protein by the granule fraction was observed using sonicated but not intact granules, suggesting that the variant protein is unlikely to be degraded by the granules in intact cells. To identify the enzyme(s) involved, we examined the effects of various enzyme inhibitors on the degradation of variant protein by the cytosol fraction. Degradation was completely inhibited by proline-specific serine protease (prolyl endopeptidase) inhibitors but not by proteasome, calpain, and metalloprotease inhibitors. Furthermore, the variant protein was degraded by a purified prolyl endopeptidase, and the degradation was protected by treating HL-60 cells with a cell-permeable inhibitor (S17092-1) for prolyl endopeptidase. These observations suggest that a cytosolic prolyl endopeptidase is involved in the degradation of p40-phox variant protein in myeloid cells.

Evaluation of the expression of NADPH oxidase components during maturation of HL-60 clone 15 cells to eosinophilic lineage.

OBJECTIVE: Superoxide-generating NADPH oxidase consists of the membrane-bound cytochrome b558 (gp91phox and p22Phox) and the cytosolic components (p67phox, p47phox, p40phox and rac). In this study, we evaluated the superoxide-generating activity and the expression of NADPH oxidase components during eosinophilic maturation using HL-60 clone 15 cell line. MATERIALS AND METHODS: HL-60 clone 15 cells were matured to eosinophils by incubation with 0.5 mM butyrate for 7 days, and NADPH oxidase components were detected by Northern blot, Western blot analyses and immunocytochemical staining. Moreover, superoxide-generating activity was examined by nitro blue tetrazolium (NBT) assay. RESULTS: Northern blot and Western blot analyses revealed that mRNAs and proteins for gp91phox, p67phox and p47phox were expressed after eosinophilic myelocyte stages, whereas mRNAs and proteins for p40phox and rac-2 were expressed from the promyelocyte stage. Interestingly, p22phox mRNA was expressed from the promyelocyte stage, but its protein was expressed after eosinophilic myelocyte stages. Consistent with the results of Western blotting, immunocytochemical staining of butyrate-induced HL-60 clone 15 cells indicated that gp91phox, p22phox, p67phox and p47phox were detected after eosinophilic myelocyte stages (eosinophilic myelocytes, eosinophilic metamyelocytes, eosinophilic band cells and eosinophilic-segmented cells), whereas p40phox and rac-2 were expressed from the promyelocyte stage. Moreover, almost the same results as those with butyrate-treated HL-60 clone 15 cells were obtained using human bone marrow cells by immunocytochemical staining. Furthermore, nitro blue tetrazolium (NBT) assay indicated that superoxide could be produced after eosinophilic myelocyte stages but not produced before the promyelocyte stage. CONCLUSIONS: Together these observations indicate that all the components for NADPH oxidase are expressed, and the superoxide-producing activity is obtained after myelocyte stages during eosinophilic maturation.

Evaluation of the effects of peptide antibiotics human beta-defensins-1/-2 and LL-37 on histamine release and prostaglandin D(2) production from mast cells.

Antimicrobial peptides, human beta-defensins (hBD-1/-2), and LL-37 (a peptide of human cathelicidin CAP18) are predominately expressed at epithelial tissues, where they participate in the innate host defense by killing invading microorganisms. In this study, to investigate the interactions between epithelial cell-derived antimicrobial peptides and mast cells, we evaluated the effects of hBD-1/-2 and LL-37 on mast cell functions using rat peritoneal mast cells. hBD-2 and LL-37 but not hBD-1 induced histamine release and intracellular Ca(2+) mobilization, and hBD-2 was more potent than LL-37. Interestingly, histamine release and intracellular Ca(2+) mobilization elicited by hBD-2 and LL-37 were markedly suppressed by BAPTA-AM (an intracellular Ca(2+) chelating agent), pertussis toxin and U-73122 (a phospholipase C inhibitor). In addition, among the peptides examined, only hBD-2 significantly induced PGD(2) production, which was abolished by indomethacin (cyclooxygenase-1/-2 inhibitor) but not NS-398 (cyclooxygenase-2 inhibitor), suggesting that hBD-2-induced PGD(2) production is mediated by cyclooxygenase-1. Likewise, the PGD(2) production was suppressed by pertussis toxin and U-73122. These observations suggest that hBD-2 and LL-37 stimulate mast cells to mobilize intracellular Ca(2+) and release histamine or generate PGD(2) in a G protein-phospholipase C-dependent manner. Thus, hBD-2 and LL-37 may have modulatory effects on inflammatory reactions.

Activated peritoneal macrophages inhibit the proliferation of rat ascites hepatoma AH-130 cells via the production of tumor necrosis factor-alpha and nitric oxide.

OBJECTIVE: To study the effect of peritoneal macrophages on tumor cell proliferation, we cultured ascites hepatoma AH-130 cells with unstimulated, or lipopolysaccharide (LPS)- or interleukin (IL)-2-stimulated rat peritoneal macrophages, and examined the proliferation of AH-130 cells. MATERIALS AND METHODS: Rat peritoneal macrophages isolated from male Wistar rats were co-cultured with AH-130 cells in the absence or presence of LPS or IL-2. After incubation, proliferation of AH-130 cells was analyzed using flow cytometry. In addition, the levels of tumor necrosis factor (TNF)-alpha and nitric oxide (NOx, nitrate + nitrite) in the culture supernatants were measured. Furthermore, anti-TNF-alpha antibody (10 microg/ml) and nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine (L-NMMA, 100 microM) were added to the coculture, and their effect on AH-130 cell proliferation was examined. RESULTS: When AH-130 cells were co-cultured with unstimulated peritoneal macrophages, proliferation of AH-130 cells was not affected. In contrast, when AH-130 cells were cocultured with peritoneal macrophages in the presence of LPS (0.1-20 microg/ml) or IL-2 (1-200 U/ml), proliferation of AH130 cells was dose-dependently suppressed by LPS or IL-2. Moreover, LPS- or IL-2-stimulation increased the levels of TNF-alpha and NOx in the supernatants of AH-130 cell and macrophage co-culture, although LPS and IL-2 did not induce TNF-alpha and NOx production by AH-130 cells incubated without macrophages. Interestingly, anti-TNF-alpha antibody and L-NMMA significantly inhibited the suppression of AH-130 cell proliferation by LPS- or IL-2-stimulated macrophages (p < 0.05). Furthermore, exogenously added recombinant rat TNF-alpha (0.26-1300 ng/ml) or NO donor (GSNO, S-nitroso-L-glutathione) (0.1 - 10 mM) dose-dependently suppressed the proliferation of AH-130 cells in the absence of macrophages. CONCLUSION: Together these observations suggest that when peritoneal macrophages are activated by LPS and IL-2, they suppress the proliferation of ascites hepatoma AH-130 cells via the production of TNF-alpha and nitric oxide.

Evaluation of the expression of NADPH oxidase components during maturation of HL-60 cells to neutrophil lineage.

To understand the expression of NADPH oxidase components during neutrophil maturation, we examined the expression of mRNAs and proteins for NADPH oxidase components, and the superoxide-producing activity using HL-60 cells incubated with dimethyl sulfoxide (DMSO). Northern blot and Western blot analyses revealed that gp91(phox), p67(phox), and p47(phox) were expressed after myelocyte stages, whereas p22(phox), p40(phox), and rac-2 were expressed from the promyelocyte stage. Furthermore, immunocytochemical staining of DMSO-induced HL-60 cells indicated that gp91(phox), p67(phox), and p47(phox) were detected only after myelocyte stages (myelocytes, metamyelocytes, band cells, and segmented cells), whereas p22(phox), p40(phox), and rac-2 were detected from the promyelocyte stage. In addition, nitro blue tetrazolium (NBT) assay showed that superoxide could be produced after myelocyte stages but not produced before promyelocyte stages. Moreover, almost the same results as those with DMSO-induced HL-60 cells were obtained using human bone-marrow cells by immunocytochemical staining and NBT assay, except that p22(phox) was detected by immunocytochemical staining after myelocyte stages in bone-marrow cells. Together, these observations indicate that all the components for NADPH oxidase are expressed, and the superoxide-producing activity is obtained after myelocyte stages during neutrophil maturation.

Increased expression of matrix metalloproteinase-9 in neutrophils in glycogen-induced peritoneal inflammation of guinea pigs.

OBJECTIVE: Matrix metalloproteinase (MMP)-9 plays an important role in neutrophil extravasation and migration by its ability to degrade the major components of basement membrane. To evaluate the expression of neutrophil MMP-9 under inflammatory conditions, we examined the levels of MMP-9 and its mRNA in neutrophils of glycogen-induced peritoneal inflammation. MATERIALS AND METHODS: Male Hartley guinea pigs weighing 250-300 g were intraperitoneally injected with 0.17% glycogen solution, and 13-15 h after the injection, blood and peritoneal neutrophils were isolated. The levels of MMP-9 and its mRNA were analyzed by gelatin zymography and Northern blotting, respectively. Furthermore, MMP-9 activities in the peritoneal supernatants were measured. RESULTS: MMP-9 level in peritoneal neutrophils was essentially the same as that in blood neutrophils, although peritoneal neutrophils were assumed to have extracellularly released MMP-9 from the granules during infiltration into the peritoneal cavity. Interestingly, MMP-9 mRNA was expressed more abundantly in peritoneal neutrophils than in blood neutrophils (p<0.01). Moreover, MMP-9 levels in blood and peritoneal neutrophils were reduced to 30-45% of non-treated controls by actinomycin D (500 microg/kg) or cycloheximide (10 mg/kg)-treatment (p<0.05). In contrast, MMP-9 activity increased in the peritoneal supernatants of glycogen-injected animals was not significantly affected by actinomycin D- or cycloheximide-treatment. In addition, when blood neutrophils of non-injected animals were stimulated with 10(-7) M N-formyl-Met-Leu-Phe, 10 microg/ml lipopolysaccharide, 10 ng/ml phorbol 12-myristate 13-acetate, 10(-8) M IL-8 or 100 U/ml tumor necrosis factor-a, expression of MMP-9 mRNA was markedly increased (p<0.05). CONCLUSIONS: The present observations indicate that MMP-9 gene is transcribed, and MMP-9 protein is synthesized in neutrophils during glycogen-injected peritoneal inflammation. Moreover, it is likely that MMP-9 protein in the peritoneal supernatants is mostly derived from preformed MMP-9 which is stored in the neutrophil granules and extracellularly released during infiltration of neutrophils into the peritoneal cavity. Finally, the transcription of MMP-9 gene can be upregulated in neutrophils by stimulation with inflammatory mediators, even after neutrophils have been matured.