Dangguishaoyao-San attenuates LPS-induced neuroinflammation via the TLRs/NF-κB signaling pathway.

INTRODUCTION: Dangguishaoyao-San (DSS) is composed of six traditional Chinese medicines, including Angelica sinensis, Paeoniae radix, Rhizoma Ligusticum, Poria cocos, Rhizoma Atractylodis Macrocephalae, and Rhizoma Alismatis. DSS has been reported to be effective in alleviating the symptoms of Alzheimer's disease (AD). The aim of this study was to investigate the mechanism of action of DSS in vitro using lipopolysaccharide (LPS)-stimulated BV-2 microglia cells. MATERIALS AND METHODS: BV-2 cells were pretreated with 0.58-1.16 mg/mL of DSS for 2 h and then treated with 1 µg/mL LPS for 24 h. Cell viability was determined by an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The protein expression levels were measured by Western blots. Inflammatory factors were detected by enzyme-linked immunosorbent assays (ELISAs). The mRNA levels of inflammatory factors were analyzed by quantitative real-time PCR (qRT-PCR). RESULTS: DSS treatment at concentrations of 0.58-1.16 mg/mL resulted in no significant cytotoxicity. DSS attenuated the release of pro-inflammatory factors, such as interleukin-1ß (IL-1ß), iNOS and tumor necrosis factor-α (TNF-α) in LPS-induced BV-2 cells. DSS attenuated the mRNA expression of pro-inflammatory cytokines, TLR2, and TLR4 and decreased TLR4 and TLR protein levels as well as the phosphorylation of IκB in LPS-induced BV-2 cells. DSS also down-regulated the nuclear translocation of p65. CONCLUSION: This study demonstrated that DSS has a protective effect on neuroinflammation in LPS-induced BV-2 microglia cells through the TLRs/NF-κB signaling pathway.

Effects of Musca domestica cecropin on the adhesion and migration of human hepatocellular carcinoma BEL-7402 cells.

This study was designed to explore the effects of Musca domestica antimicrobial peptides cecropin on the adhesion and migration of human hepatocellular carcinoma BEL-7402 cells. The adhesive and migratory capacities were determined by adhesion assay and transwell assay, respectively. The changes in microvilli of tumor cells were determined by scanning electron microscopy (SEM). Western blotting and quantitative polymerase chain reaction (qPCR) were carried out to determine the expression levels of proteins related to adhesion and migration, such as matrix metalloproteinase-2 (MMP2), tissue inhibitors of metalloproteinase-2 (TIMP2), and epithelial cadherin (E-cadherin). We found that Musca domestica cecropin inhibited the adhesion and migration of BEL-7402 cells, which also displayed curling microvilli, increased ball structures on cell surface, gradually broken connections between tumor cells, and even disappeared microvilli on some cells. The expression of MMP2 was significantly reduced after cecropin treatment, while the levels of TIMP2 and E-cadherin were significantly increased. These results suggest that Musca domestica cecropin inhibits the adhesion and migration of human hepatocellular carcinoma BEL-7402 cells by destroying the microvilli of tumor cells and changing the expression of MMP2, TIMP2 and E-cadherin.

ß-defensin 2 as an adjuvant promotes anti-melanoma immune responses and inhibits the growth of implanted murine melanoma in vivo.

ß-defensin 2 is a small antimicrobial peptide of the innate immune system and has been thought to regulate anti-tumor immunity. However, little is known on whether ß-defensin 2 could modulate melanoma-specific NK and T cell responses. In this study, we first cloned the murine ß-defensin 2 gene by RT-PCR and generated the ß-defensin 2 stably expressing B16 cells (B16-mBD2). Subsequently, we evaluated whether vaccination with irradiated B16-mBD2 could modulate the growth of implanted B16 cells and determined the potential mechanisms underlying the action of B16-mBD2 vaccine in modulating the growth of B16 tumors in C57BL/6. We found that vaccination with irradiated B16-mBD2, but not with control B16-p or parental B16, inhibited the development and progression of B16 tumors, and prolonged the survival of tumor-bearing mice. However, vaccination with irradiated B16-mBD2 failed to inhibit the development of B16 tumors in the CD4(+)- or CD8(+)-depleted recipients. Furthermore, vaccination with irradiated B16-mBD2 stimulated strong NK activity and promoted potent B16-specific CTL responses, accompanied by augmenting IFN-γ and IL-12, but not IL-4, responses in the recipient mice. Moreover, vaccination with irradiated B16-mBD2 promoted the infiltration of CD8(+) and CD4(+) T, NK cells and macrophages in the tumor tissues. These data suggest ß-defensin 2 may act as a positive regulator, promoting anti-tumor NK and T cell responses in vivo. Therefore, ß-defensin 2 may be used for the development of immunotherapy for the intervention of melanoma.

Expression of a novel dual-functional protein--the antimicrobial peptide LL-37 fused with human acidic fibroblast growth factor in Escherichia coli.

Human acidic fibroblast growth factor (haFGF) stimulates repair of delayed healing which still remains a tremendously world-wide issue. However, most of the patients with delayed healings have to face another creeping problem - microbial infection, which is one of the most frequent complications that still lead to wound healing failure. LL-37/hCAP-18 is the only cathelicidin-derived antimicrobial peptide found in human with a wide range of antimicrobial activities. In the present study, a novel hybrid protein combining LL-37 with haFGF was designed. The DNA sequence encoding recombination fusion protein LL-37-haFGF was subcloned into the pET-21b vector for protein expression in Escherichia coli strain BL21 (DE3). The recombinant protein was expressed as a His-tagged protein and purified using a combination of Ni affinity and CM-Sepharose chromatography at a purity of 95.43% as detected by RP-HPLC and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Antimicrobial activity assays showed that the purified LL-37-haFGF had improved antimicrobial activities in vitro compared with LL-37. Methylthiazoletetrazolium (MTT) assay showed that the purified LL-37-haFGF also had a distinct mitogenic activity in NIH 3T3 cells. These data suggests the recombinant protein LL-37-haFGF has pharmaceutical potential for applications in wound healing.

[The target of Musca domestica cecropin on human hepatocellular carcinoma BEL-7402 cells].

Human hepatocellular carcinoma BEL-7402 cells were treated with 50 micromol/L Musca domestica cecropin for 12 h, and observed under scanning electron microscope. The effect of Musca domestica cecropin labeled with FITC (FITC-cecropin) on BEL-7402 cells was detected by laser scanning confocal microscopy. The scanning electron microscopy showed that most microvilli on the surface of BEL-7402 cells disappeared at 12 h after cecropin treatment. The laser scanning confocal microscopy revealed that most FITC-cecropin combined with BEL-7402 cell membrane, and partly in the cytoplasm.

Expression of the antimicrobial peptide cecropin fused with human lysozyme in Escherichia coli.

Lysozyme is an abundant, cationic antimicrobial protein that plays an important role in host defense. It targets the beta (1-4) glycosidic bond between N-acetylglucosamine and N-acetylmuramic residues that make up peptidoglycan, making lysozyme highly active against Gram-positive bacteria. However, lysozyme alone is inactive against Gram-negative bacteria because it cannot reach the peptidoglycan layer. Cecropins are cationic molecules with a wide range of antimicrobial activities. The main target for these peptides is the cytoplasmic membrane. We resume that cecopin may disrupt the outer membrane, giving the enzyme access to the peptidoglycan in cell wall. So in the present study, novel hybrid protein combining Musca domestica cecropin (Mdc) with human lysozyme (Hly) was designed. The DNA sequence encoding recombination fusion protein Mdc-hly was cloned into the pET-32a vector for protein expression in Escherichia coli strain BL21 (DE3). The protein was expressed as a His-tagged fusion protein, and the Mdc-hly was released from the fusion by enterokinase cleavage and separated from the carrier thioredoxin. Antimicrobial activity assays showed that the recombinant fusion protein Mdc-hly has improved in vitro antimicrobial activity and action spectrum compared to Mdc and hly. Mdc-hly may have important potential application as a future safely administered human drug and food additive.

[Relation between beta-amyloid peptide-25-35 inducing cell cycle change and apoptosis of serum-deprived PC12 cell].

OBJECTIVE: To study the relation between cell cycle change and apoptosis of serum-deprived PC12 cell, which are induced by beta-amyloid peptide-25-35 (alpha beta(25-35)). METHODS: PC12 cells were synchronized by cultured in deprivation of serum for 24 h and treated with different concentration of alpha beta(25-35) (0-45 micromol/L) for another 24 h,and the cell survival rate was evaluated by MTT assay. The cell apoptosis was analyzed by Hoechst fluorescence staining and DNA agarose gel electrophoresis. The relation between cell cycle redistribution and apoptosis was analyzed by flow cytometry (FCM). RESULTS: alpha beta(25-35) decreased the survival rate of PC12 cells in dose-dependent manner. The typical apoptotic cells were showed by fluorescence staining when treated with 25 micromol/L alpha beta(25-35) for 24 h;the obvious DNA-Ladder was showed by DNA agarose electrophoresis. About 90% PC12 cells were found to arrest on G0/G1 by FCM being deprived serum. Treated with 25 micromol/L alpha beta(25-35) for 8, 16, 24 h, the percent of S phase cells was raised remarkably (P < 0.01) at 8 h, but the percent of S phase cells was declined gradually after treated for 16 h. Meanwhile the apoptotic rate was detected being increased obviously between 16 h and 24 h (P < 0.01), the obvious hypodiploid peak could be observed ahead of G0/G1 phase(Ap). CONCLUSION: alpha beta(25-35) decreases the survival rate of synchronized PC12 cell and induces the synchronized PC12 cells attempting to reenter cell cycle,which appear the apoptotic peak subsequently. This indicates that the cell apoptosis may be related to the abnormal cell cycle distribution induced by alpha beta(25-35), which means there may be a close relationship between cell cycle and apoptosis.