Degradation of EGFR on lung epithelial cells by neutrophil elastase contributes to the aggravation of pneumococcal pneumonia.

Pneumococcus is the main cause of bacterial pneumonia. Pneumococcal infection has been shown to cause elastase, an intracellular host defense factor, to leak from neutrophils. However, when neutrophil elastase (NE) leaks extracellularly, it can degrade host cell surface proteins such as epidermal growth factor receptor (EGFR) and potentially disrupt the alveolar epithelial barrier. In this study, we hypothesized that NE degrades the extracellular domain (ECD) of EGFR in alveolar epithelial cells and inhibits alveolar epithelial repair. Using SDS-PAGE, we showed that NE degraded the recombinant EGFR ECD and its ligand epidermal growth factor, and that the degradation of these proteins was counteracted by NE inhibitors. Furthermore, we confirmed the degradation by NE of EGFR expressed in alveolar epithelial cells in vitro. We showed that intracellular uptake of epidermal growth factor and EGFR signaling was downregulated in alveolar epithelial cells exposed to NE and found that cell proliferation was inhibited in these cells These negative effects of NE on cell proliferation were abolished by NE inhibitors. Finally, we confirmed the degradation of EGFR by NE in vivo. Fragments of EGFR ECD were detected in bronchoalveolar lavage fluid from pneumococcal pneumonia mice, and the percentage of cells positive for a cell proliferation marker Ki67 in lung tissue was reduced. In contrast, administration of an NE inhibitor decreased EGFR fragments in bronchoalveolar lavage fluid and increased the percentage of Ki67-positive cells. These findings suggest that degradation of EGFR by NE could inhibit the repair of alveolar epithelium and cause severe pneumonia.

Matcha Green Tea Exhibits Bactericidal Activity against Streptococcus pneumoniae and Inhibits Functional Pneumolysin.

Streptococcus pneumoniae is a causative pathogen of several human infectious diseases including community-acquired pneumonia. Pneumolysin (PLY), a pore-forming toxin, plays an important role in the pathogenesis of pneumococcal pneumonia. In recent years, the use of traditional natural substances for prevention has drawn attention because of the increasing antibacterial drug resistance of S. pneumoniae. According to some studies, green tea exhibits antibacterial and antitoxin activities. The polyphenols, namely the catechins epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC) are largely responsible for these activities. Although matcha green tea provides more polyphenols than green tea infusions, its relationship with pneumococcal pneumonia remains unclear. In this study, we found that treatment with 20 mg/mL matcha supernatant exhibited significant antibacterial activity against S. pneumoniae regardless of antimicrobial resistance. In addition, the matcha supernatant suppressed PLY-mediated hemolysis and cytolysis by inhibiting PLY oligomerization. Moreover, the matcha supernatant and catechins inhibited PLY-mediated neutrophil death and the release of neutrophil elastase. These findings suggest that matcha green tea reduces the virulence of S. pneumoniae in vitro and may be a promising agent for the treatment of pneumococcal infections.

Treatment of severe pneumonia by hinokitiol in a murine antimicrobial-resistant pneumococcal pneumonia model.

Streptococcus pneumoniae is often isolated from patients with community-acquired pneumonia. Antibiotics are the primary line of treatment for pneumococcal pneumonia; however, rising antimicrobial resistance is becoming more prevalent. Hinokitiol, which is isolated from trees in the cypress family, has been demonstrated to exert antibacterial activity against S. pneumoniae in vitro regardless of antimicrobial resistance. In this study, the efficacy of hinokitiol was investigated in a mouse pneumonia model. Male 8-week-old BALB/c mice were intratracheally infected with S. pneumoniae strains D39 (antimicrobial susceptible) and NU4471 (macrolide resistant). After 1 h, hinokitiol was injected via the tracheal route. Hinokitiol significantly decreased the number of S. pneumoniae in the bronchoalveolar lavage fluid (BALF) and the concentration of pneumococcal DNA in the serum, regardless of whether bacteria were resistant or susceptible to macrolides. In addition, hinokitiol decreased the infiltration of neutrophils in the lungs, as well as the concentration of inflammatory cytokines in the BALF and serum. Repeated hinokitiol injection at 18 h intervals showed downward trend in the number of S. pneumoniae in the BALF and the concentration of S. pneumoniae DNA in the serum with the number of hinokitiol administrations. These findings suggest that hinokitiol reduced bacterial load and suppressed excessive host immune response in the pneumonia mouse model. Accordingly, hinokitiol warrants further exploration as a potential candidate for the treatment of pneumococcal pneumonia.

Erythromycin inhibits neutrophilic inflammation and mucosal disease by upregulating DEL-1.

Macrolide antibiotics exert antiinflammatory effects; however, little is known regarding their immunomodulatory mechanisms. In this study, using 2 distinct mouse models of mucosal inflammatory disease (LPS-induced acute lung injury and ligature-induced periodontitis), we demonstrated that the antiinflammatory action of erythromycin (ERM) is mediated through upregulation of the secreted homeostatic protein developmental endothelial locus-1 (DEL-1). Consistent with the anti-neutrophil recruitment action of endothelial cell-derived DEL-1, ERM inhibited neutrophil infiltration in the lungs and the periodontium in a DEL-1-dependent manner. Whereas ERM (but not other antibiotics, such as josamycin and penicillin) protected against lethal pulmonary inflammation and inflammatory periodontal bone loss, these protective effects of ERM were abolished in Del1-deficient mice. By interacting with the growth hormone secretagogue receptor and activating JAK2 in human lung microvascular endothelial cells, ERM induced DEL-1 transcription that was mediated by MAPK p38 and was CCAAT/enhancer binding protein-ß dependent. Moreover, ERM reversed IL-17-induced inhibition of DEL-1 transcription, in a manner that was dependent not only on JAK2 but also on PI3K/AKT signaling. Because DEL-1 levels are severely reduced in inflammatory conditions and with aging, the ability of ERM to upregulate DEL-1 may lead to a novel approach for the treatment of inflammatory and aging-related diseases.

Antibacterial activity of hinokitiol against both antibiotic-resistant and -susceptible pathogenic bacteria that predominate in the oral cavity and upper airways.

Hinokitiol, a component of the essential oil isolated from Cupressaceae, possesses antibacterial and antifungal activities and has been used in oral care products. In this study, the antibacterial activities of hinokitiol toward various oral, nasal and nasopharyngeal pathogenic bacteria, including Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Fusobacterium nucleatum, methicillin-resistant and -susceptible Staphylococcus aureus, antibiotic-resistant and -susceptible Streptococcus pneumoniae, and Streptococcus pyogenes were examined. Growth of all these bacterial strains was significantly inhibited by hinokitiol, minimal inhibitory concentrations of hinokitiol against S. mutans, S. sobrinus, P. gingivalis, P. intermedia, A. actinomycetemcomitans, F. nucleatum, methicillin-resistant S. aureus, methicillin-susceptible S. aureus, antibiotic-resistant S. pneumoniae isolates, antibiotic-susceptible S. pneumoniae, and S. pyogenes being 0.3, 1.0, 1.0, 30, 0.5, 50, 50, 30, 0.3-1.0, 0.5, and 0.3 µg/mL, respectively. Additionally, with the exception of P. gingivalis, hinokitiol exerted bactericidal effects against all bacterial strains 1 hr after exposure. Hinokitiol did not display any significant cytotoxicity toward the human gingival epithelial cell line Ca9-22, pharyngeal epithelial cell line Detroit 562, human umbilical vein endothelial cells, or human gingival fibroblasts, with the exception of treatment with 500 µg/mL hinokitiol, which decreased numbers of viable Ca9-22 cells and gingival fibroblasts by 13% and 12%, respectively. These results suggest that hinokitiol exhibits antibacterial activity against a broad spectrum of pathogenic bacteria and has low cytotoxicity towards human epithelial cells.

Aggregatibacter actinomycetemcomitans induces detachment and death of human gingival epithelial cells and fibroblasts via elastase release following leukotoxin-dependent neutrophil lysis.

Aggregatibacter actinomycetemcomitans is considered to be associated with periodontitis. Leukotoxin (LtxA), which destroys leukocytes in humans, is one of this bacterium's major virulence factors. Amounts of neutrophil elastase (NE), which is normally localized in the cytoplasm of neutrophils, are reportedly increased in the saliva of patients with periodontitis. However, the mechanism by which NE is released from human neutrophils and the role of NE in periodontitis is unclear. In the present study, it was hypothesized that LtxA induces NE release from human neutrophils, which subsequently causes the breakdown of periodontal tissues. LtxA-treatment did not induce significant cytotoxicity against human gingival epithelial cells (HGECs) or human gingival fibroblasts (HGFs). However, it did induce significant cytotoxicity against human neutrophils, leading to NE release. Furthermore, NE and the supernatant from LtxA-treated human neutrophils induced detachment and death of HGECs and HGFs, these effects being inhibited by administration of an NE inhibitor, sivelestat. The present results suggest that LtxA mediates human neutrophil lysis and induces the subsequent release of NE, which eventually results in detachment and death of HGECs and HGFs. Thus, LtxA-induced release of NE could cause breakdown of periodontal tissue and thereby exacerbate periodontitis.

Peptides from rice endosperm protein restrain periodontal bone loss in mouse model of periodontitis.

OBJECTIVE: Food-derived peptides have been reported to exhibit antibacterial activity against periodontal pathogenic bacteria. However, no effect has been shown on inflammation and bone resorption in periodontal pathology. The overall objective of the current study was to investigate how rice peptides influence biological defense mechanisms against periodontitis-induced inflammatory bone loss, and identify their novel functions as a potential anti-inflammatory drug. DESIGN: The expression of inflammatory and osteoclast-related molecules was examined in mouse macrophage-derived RAW 264.7 cell cultures using qPCR. Subsequently, the effect of these peptides on inflammatory bone loss in mouse periodontitis was examined using a mouse model of tooth ligation. Briefly, periodontal bone loss was induced for 7 days in mice by ligating the maxillary second molar and leaving the contralateral tooth un-ligated (baseline control). The mice were microinjected daily with the peptide in the gingiva until the day before euthanization. One week after the ligation, TRAP-positive multinucleated cells (MNCs) were enumerated from five random coronal sections of the ligated sites in each mouse. RESULTS: Rice peptides REP9 and REP11 significantly inhibited transcription activity of inflammatory and osteoclast-related molecules. Local treatment with the rice peptides, in mice subjected to ligature-induced periodontitis, inhibited inflammatory bone loss, explaining the decreased numbers of osteoclasts in bone tissue sections. CONCLUSION: Therefore, these data suggested that the rice peptides possess a protective effect against periodontitis.

Immunization with pneumococcal elongation factor Tu enhances serotype-independent protection against Streptococcus pneumoniae infection.

Vaccination is an effective strategy to prevent pneumococcal diseases. Currently, licensed vaccines include the pneumococcal polysaccharide vaccine (PPSV) and the pneumococcal conjugate vaccine (PCV), which target some of the most common of the 94 serotypes of S. pneumoniae based on their capsular composition. However, it has been reported that PPSV is not effective in children aged less than 2 years old and PCV induces serotype replacement, which means that the pneumococcal population has changed following widespread introduction of these vaccines, and the non-vaccine serotypes have increased in being the cause of invasive pneumococcal disease. Therefore, it is important that there is development of novel pneumococcal vaccines to either replace or complement current polysaccharide-based vaccines. Our previous study suggested that S. pneumoniae releases elongation factor Tu (EF-Tu) through autolysis followed by the induction of proinflammatory cytokines in macrophages via toll-like receptor 4, that may contribute to the development of pneumococcal diseases. In this study, we investigated the expression of EF-Tu in various S. pneumoniae strains and whether EF-Tu could be an antigen candidate for serotype-independent vaccine against pneumococcal infection. Western blotting and flow cytometry analysis revealed that EF-Tu is a common factor expressed on the surface of all pneumococcal strains tested, as well as intracellularly. In addition, we demonstrate that immunization with recombinant (r) EF-Tu induced the production of inflammatory cytokines and the IgG1 and IgG2a antibodies in mice, and increased the CD4+ T-cells proportion in splenocytes. We also reveal that anti-EF-Tu serum increased the phagocytic activity of mouse peritoneal macrophages against S. pneumoniae infection, independent of their serotypes. Finally, our results indicate that mice immunized with rEF-Tu were significantly and non-specifically protected against lethal challenges with S. pneumoniae serotypes (2 and 15A). Therefore, pneumococcal EF-Tu could be an antigen candidate for the serotype-independent vaccine against pneumococcal infection.

Pneumococcal DNA-binding proteins released through autolysis induce the production of proinflammatory cytokines via toll-like receptor 4.

Streptococcus pneumoniae is a leading cause of bacterial pneumonia. Our previous study suggested that S. pneumoniae autolysis-dependently releases intracellular pneumolysin, which subsequently leads to lung injury. In this study, we hypothesized that pneumococcal autolysis induces the leakage of additional intracellular molecules that could increase the pathogenicity of S. pneumoniae. Liquid chromatography tandem-mass spectrometry analysis identified that chaperone protein DnaK, elongation factor Tu (EF-Tu), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were released with pneumococcal DNA by autolysis. We demonstrated that recombinant (r) DnaK, rEF-Tu, and rGAPDH induced significantly higher levels of interleukin-6 and tumor necrosis factor production in peritoneal macrophages and THP-1-derived macrophage-like cells via toll-like receptor 4. Furthermore, the DNA-binding activity of these proteins was confirmed by surface plasmon resonance assay. We demonstrated that pneumococcal DnaK, EF-Tu, and GAPDH induced the production of proinflammatory cytokines in macrophages, and might cause host tissue damage and affect the development of pneumococcal diseases.

[Investigation of FOLFIRI/FOLFOX (+/-bevacizumab) therapy for patients with metastatic colorectal cancer in our hospital].

UNLABELLED: Bevacizumab has been demonstrated to prolong survival in patients with metastatic colorectal cancer when used in combination with chemotherapy. We investigated the efficacy of chemotherapy administered in our general hospital for patients with metastatic colorectal cancer after the introduction of FOLFOX/FOLFIRI (+/-bevacizumab) therapy. SUBJECTS AND METHODS: The subjects in this study were 34 patients diagnosed with metastatic colorectal cancer, who received either FOLFIRI (+/- bevacizumab) or mFOLFOX6 (+/-bevacizumab) therapy in this hospital. The subjects were divided into a bevacizumab combination regimen group (those who received the regimen as first-line treatment), and a non-bevacizumab combination regimen group (those who did not receive the regimen as first-line treatment). Comparisons were made with regard to anticancer efficacy, progression-free survival time, and overall survival time. RESULTS: Comparison between the bevacizumab combination regimen group and the non-bevacizumab combination regimen group, revealed no significant difference due to the small number of relevant patients. However, the former showed a slight advantage over the latter in terms of anti-cancer efficacy and progression-free survival time. CONCLUSION: Bevacizumab is expected to contribute to the prolongation of survival in patients in our general hospital.

[A clinical results of TS-1 in advanced and recurrent gastric cancer in our hospital].

A total of 40 patients with advanced and recurrent gastric cancer in our hospital were treated with TS-1 alone, and the efficacy of treatment, survival time, and adverse effects were examined. TS-1 was administered with the usual dosage and dose regimen. Response to treatment included a complete response (CR) in 3 cases, partial response (PR) in 8 cases, no change (NC) in 10 cases, and progressive disease (PD) in 7 cases. The response rate was 39.3%, and among the 28 patients with evaluable lesions TS-1 produced a high response rate of 56.3% in 16 patients who had undergone prior therapy. The median survival time (MST) was 478 days in the 28 patients with evaluable lesions, excluding patients with peritoneal dissemination, and 283 days in the 12 patients with peritoneal dissemination. The outcome was markedly poorer in the patients with peritoneal dissemination than in the patients with evaluable lesions. The incidence of grade 3 or higher adverse effects was 20%, including two cases in which decreased dihydropyrimidine dehydrogenase (DPD) activity was suspected, and one case in which decreased dihydropyrimidinase (DHP) was suspected. Although the effect of TS-1 alone on gastric cancer is significantly superior to that of any conventional cancer drugs, the results of this study suggest that the antitumor effect varies with the site of the target lesions and according to whether the lesion is a remnant or recurrence.

[Combined chemoendocrine therapy using adriamycin, cyclophosphamide and high dose toremifene in patients with recurrent breast cancer].

We studied a new chemoendocrine therapy against recurrent breast cancer in order to evaluate its efficacy and toxicity. Sixteen eligible patients were treated with the therapy consisting of adriamycin/cyclophosphamide (AC) plus toremifene (TOR). Adriamycin (20 mg/m2) was administered intravenously on days 1 and 8, and cyclophosphamide (100 mg/body) was given orally on days 1 to 14 every 4 weeks. TOR (120 mg/day) was given orally daily. The median age of the patients was 52 years; 6 were premenopausal and 10 postmenopausal. As post-operative adjuvant therapy, anthracycline chemotherapy and tamoxifen were given to 4 and 9 patients, respectively. AC therapy was administered for 8.5 cycles (median). Four complete responses (25%), 8 partial responses (37.5%), 4 no change (25%) (including 2 long NC), and 2 progressive disease (12.5%) were obtained, for an overall response rate of 62.5%. The median duration of time to progression and survival were 13.2 months (0.7-30.4 months) and 22.8 months (13.7-44.8 + months), respectively. The frequent toxicities were leukopenia, nausea/vomiting, and alopecia, but these were clinically well tolerated. Our results suggest that the addition of high dose TOR to AC therapy is useful in the treatment of recurrent breast cancer.

[A case of residual gastric cancer accompanied by esophageal invasion in which residual lesions were eradicated by half-dose administration of TS-1].

The patient was a 64-year-old male. On November 21, 1991, he underwent gastric resection on the pyloric side for early gastric cancer in the authors' hospital, and did not experience recurrence for many years thereafter. However, endoscopic examination of the upper gastrointestinal tract performed on June 11, 1999 revealed advanced cancer in the posterior wall of the residual stomach which was accompanied by invasion of the esophagus. Thus, the residual stomach was completely removed on July 5, 1999. The histopathological findings were tub1, se, ly3, v2, aw(-), ow(+) and ew(+), and a portion of the esophageal stump and the serosa of the lesser curvature were positive for cancerous tissue. Endoscopic examination was performed one month after the operation, on August 7, 1999. A forceps biopsy taken from an elevated lesion of the esophagus at the posterior wall of the anastomosis revealed adenocarcinoma cells in the lower layer of the squamous epithelium. A residual esophageal lesion was thus diagnosed. Beginning on August 9, 1999, TS-1 was administered in a dosage of 50 mg bid, but it was later learned that the patient had ingested only half of that TS-1 dosage (i.e., 50 mg/day). After completion of one course of this therapy, endoscopy was again performed. It was found that the prominence on the esophageal mucosa at the anastomosis, which had been diagnosed as being cancerous tissue, had shrunk in size, while a forceps biopsy taken from the same site yielded no findings of malignancy. The patient was followed for 18 months thereafter, and endoscopy was performed three times during that interval but continued to yield no evidence of malignancy. As of February 2001, this patient had completed 12 courses of TS-1 at one-half its usual dosage. There have been no findings of recurrence, and the patient's course continues to be good. In summary, this was an interesting case in which residual cancer was detected in the esophageal stump following resection for gastric cancer, and it can be concluded that TS-1 therapy was effective in spite of being incomplete (i.e., half-dose), eradicating the residual cancer tissue.