Baicalin inhibits toll-like receptor 2/4 expression and downstream signaling in rat experimental periodontitis.

Periodontitis is a severe inflammatory response, leading to characteristic periodontal soft tissue destruction and alveolar bone resorption. Baicalin possesses potent anti-inflammatory activity; however, it is still unclear whether baicalin regulates toll-like receptor (TLR) 2/4 expression and downstream signaling during the process of periodontitis. In this study, the cervical area of the maxillary second molars of rats was ligated and inoculated with Porphyromonas gingivalis (P. gingivalis) for 4weeks to induce periodontitis. Some rats with periodontitis were treated intragastrically with baicalin (50, 100 or 200mg/kg/day) or vehicle for 4weeks. Compared with the sham group, the levels of TLR2, TLR4 and MyD88 expression and the p38 MAPK and NF-κB activation were up-regulated in the experimental periodontitis group (EPG), accompanied by marked alveolar bone loss and severe inflammation. Treatment with 100 or 200mg/kg/day baicalin dramatically reduced the alveolar bone loss, the levels of HMGB1, TNF-α, IL-1ß, and MPO expression, and the numbers of inflammatory infiltrates in the gingival tissues. Importantly, treatment with 100 or 200mg/kg/day baicalin mitigated the periodontitis-up-regulated TLR2, TLR4 and MyD88 expression, and the p38 MAPK and NF-κB activation. Hence, the blockage of the TLR2 and TLR4/MyD88/p38 MAPK/NF-κB signaling by baicalin may contribute to its anti-inflammatory effects in rat model of periodontitis. In conclusion, these novel findings indicate that baicalin inhibits the TLR2 and TLR4 expression and the downstream signaling and mitigates inflammatory responses and the alveolar bone loss in rat experimental periodontitis. Therefore, baicalin may be a potential therapeutic agent for treatment of periodontitis.

[Preliminary study of the dual release baicalin and rhBMP-2 system to improve periodontal tissue regeneration in minipigs].

PURPOSE: To explore the feasibility of dual release baicalin and rhBMP-2 system for the treatment of periodontal diseases in minipigs. METHODS: Four miniature swines were selected to establish the model of periodontitis and randomly divided them into four groups: Dual release group, hydrogel with baicalin-GMS and rhBMP-2; Single Huang group, hydrogel with baicalin-GMS; BMP group, hydrogel with rhBMP-2; Negative control group, blank hydrogel. All parameters including clinical indicators of periodontitis, the level of IL-1 and TNF-α in the gingival crevicular fluid (GCF) were measured before and 6 weeks after modeling, and 4, 8 weeks after treatment. The data was analyzed using SPSS13.0 software package. The periodontitis model animals were sacrificed at the end of 8 weeks after treatment. The histological changes of periodontal tissues were observed under microscope with HE staining. RESULTS: (1)In all groups, there were significant differences of clinical indicators and levels of IL-1 and TNF-α in the GCF between periodontitis was established and 4, 8 weeks after treatment (P<0.05). Dual release group was significantly superior than that of other three groups (P<0.05). Moreover, all the parameters improved continuously. X-ray showed that bone mineral density and height in the remaining three groups increased compared with the control group, with highest in dual release group. (2)The results of histological observation showed that the inflammation reaction of periodontal tissues in negative control group was more serious than that in other groups 8 weeks after treatment. There was no obvious repair reaction in the control group, but different amount of new bone was seen in other three groups. Among them, dual release group had most obvious repair reaction. CONCLUSIONS: The dual-slow-release chitosan thermosensitive hydrogel system is employable to be used effectively in the regeneration of periodontal defects, which laid a foundation for further clinical use.

[Cloning and expression of peptidylarginine deiminase of Porphyromonas gingivalis].

PURPOSE: To clone the peptidylarginine deiminase(PAD) gene of Porphyromonas gingivalis(P.gingivalis) and to be expressed in E. coli under the best conditions. METHODS: With P.gingivalis strains ATCC33277 genomic DNA as a template, PCR was applied to obtain gene PAD which was then inserted into linear cloning vector PMD-18-T to construct clone recon. Recombinant PMD18-T-PAD was cloned and analyzed with PCR and restriction endonuclease,and PET-28a expression vector was digested by Xhol and Ncol,their products were linked to construct expression plasmid PET-28a-PAD under certain connection system. The recombinant expression plasmid PET-28a-PAD which had been confirmed correctly was transformed to E. coli competent cells BL21 and induce the expression of PAD with IPTG of different density and time. With His Tag monoclonal antibody as the first antibody, the expressed fusion protein was characterized by Western blot. RESULTS: DNA sequencing showed that the fragment was same as the sequence published in NCBI. Under the condition of 37 degrees centigrade, 0.5mmol/L IPTG, 250r/min shaking for 6 hours, the PAD could be highly expressed. CONCLUSIONS: The PAD is successfully cloned and expressed in E. coli which can be further uesd to study the immunity of PAD and the homologues antibody preparation.

[Construction and identification of BIRC5 shRNA lentiviral expression vector].

AIM: Design and synthesis complementary DNA sequences of 3 pairs of short hairpin structure and a pair of negative control sequence by RNA interference technique and construct and identify a lentiviral interference vector with human BIRC5 gene as target gene. METHODS: The designed and synthesised Single-Stranded primer were annealed to Double-Stranded oligo sequences and subcloned into linear pMAGic lentiviral plasmid vector digested by enzyme Age I and EcoR I. Screening positive clone after transformed into DH5α competent cells and identified by PCR amplification and DNA sequencing. RESULTS: 335 bp straps of positive clone and 298 bp straps of negative clone form PCR amplification production have been obtained after gel electrophoresis, the designed and synthesised sequences have been contained in these clone straps confirmed by the result of DNA sequencing. CONCLUSION: Four pairs of BIRC5 shRNA recombinant lentiviral expression vector were constructed successfully, which laid the foundation for researching the inhibition of BIRC5 siRNA target against tumor cells proliferation, induction apoptosis and gene therapy.

[Cloning of the glyceraldehydes 3-phosphate dehydrogenase gene of porphyromonas gingivalis and its expression in E. coli].

OBJECTIVE: To clone the glyceraldehydes 3-phosphate dehydrogenase (GAPDH) gene of Porphyromonas gingivalis (P. gingivalis) and to induce its fusion expression in E. coli. METHODS: GAPDH was obtained by PCR and was inserted into cloning vector pMD-18-T to construct clone recon. Double enzymes digest the recon pMD18-T-GAPDH and the prokaryotic expression vector pET-32a and then connect to get the expressing recon pET-32a-GAPDH. The recombinant expression plasmid which had been confirmed by enzymes digestion was transformed to E. coli competent cells BL21 and induced the expression of GAPDH with isopropyl beta-D-1-thiogalactopyranoside (IPTG) of different density. RESULTS: DNA sequencing showed that the fragment was 99.802% the same to the sequence published in NCBI. Under the best density, IPTG could be highly expressed. CONCLUSION: The GAPDH had been successfully cloned and expressed in E. coli which gets ready for the following experiment to study the immunity of GAPDH and the homologues antibody preparation.

[Experimental study on the functional regulation of naringin in human periodontal ligament cells].

PURPOSE: To detect the effect of naringin on human periodontal ligament cells' (hPDLCs) proliferation,bone formation and OPG mRNA expression. METHODS: hPDLCs were primarily cultured and identified in vitro through enzyme digestion combined tissue culture method. With 3-(4, 5-Dimethylthiazol-2- yl)-2, 5-diphenyltetrazolium bromide (MTT) method, enzyme linked immunosorbent assay and RT-PCR, the hPDLCs' proliferation, alkaline phosphatase (ALP) activity, expression of collagen protein-I and OPG mRNA were observed after treatment with different concentrations (100,10,1.0,0.1,0.01mg/L) of naringin at different times. SPSS16.0 software package was used for statistical analysis. RESULTS: Primary cultured hPDLCs had good shape; Significant promotion of proliferation,ALP activity and collagen protein-I expression of hPDLCs with naringin was found at the dose of 1.0 mg/L; and 1.0mg/L naringin regulated the expression of OPG mRNA in time-dependent manner. CONCLUSION: Naringin might significantly promote the proliferation of hPDLCs and conversion into the osteoblast.

[Analysis of outer membrane proteins in various strains of Porphyromonas gingivalis by surface enhanced laser desorption/ionization time-of-flight mass spectrometry].

OBJECTIVE: To analyze the common outer membrane proteins (OMP) from Porphyromonas gingivalis (Pg) by surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) and to provide antigens for the subsequent experiments in screening vaccine for periodontitis therapy. METHODS: Four strains of Pg were cultured under anaerobic conditions. The common OMP was extracted through ultracentrifugation and SELDI-TOF-MS was employed to detect the expressions of proteomes by chip H(50). The data was analyzed by Biomarker Wizard. RESULTS: Four kinds of strains of OMP fingerprint spectrum were obtained. Seventy-one proteins of PgATCC33277, 74 proteins of PgW83, 76 proteins of PgW301 and 72 proteins of Pg381 were captured by chip H(50). Thirteen common proteins were identified according to fingerprint spectrum. There was only 1 of the 13 common proteins identified in NCBI protein bank. CONCLUSIONS: SELDI-TOF-MS has good reproducibility and high sensibility and can be used to identify the common OMP of Pg. The 13 proteins have a potential value in the screening vaccine candidate antigen sites for periodontitis.

[Construction of prokaryotic expression vector of FimA gene from Porphyromonas gingivalis, fusion expression and purification in E. coli BL21(DE3)pLyS].

OBJECTIVE: To clone the FimA gene of fimbriae from Porphyromonas gingivalis (P. gingivalis) and to construct prokaryotic expression vector which was induced in E.coli BL21(DE3)pLyS in the form of fusion protein expression and to identify, purify the product of its expression. METHODS: To clone the FimA gene of fimbriae from P. gingivalis and to construct prokaryotic expression vector pET15b-FimA vector which was transformed into the competent cells of BL21(DE3)pLyS. The expression of fusion protein was induced by isopropyl beta-D-1-thiogalactopyranoside (IPTG). With anti-6xHis Tag monoclonal antibody as the first antibody, the expressed fusion protein was characterized by Western blot and purified by Co(2+)-NTA affinity chromatography. RESULTS: Cloned FimA gene sequences and inserted into expression vector of the FimA sequences were related to the sequence in GenBank database showed 100% homology. IPTG induced and then identified by Western blot showed a fragment of 4.1 x 10(4) has been expressed. Co(2+)-NTA affinity chromatography column was used to obtain high concentrations of FimA purified protein. CONCLUSION: The recombinant prokaryotic expression vector of pET15b-FimA was constructed and was expressed and purified successfully in E. coli BL21 (DE3)pLyS. This study laid the experimental foundation to further prepare for monoclonal antibodies of fimbriae of P. gingivalis and to develop the subunit protein vaccine of prevention of periodontitis.

[A preliminary study on screening for Porphyromonas gingivalis outer membrane protein antigen with two-dimensional liquid phase fractionation and matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry].

OBJECTIVE: To screen a variety of Porphyromonas gingivalis (Pg) common outer membrane proteins with two-dimensional liquid phase fractionation (PF2D) and matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) and provide candidate target antigen for the design of vaccines with cross protection against a variety of Pg. METHODS: The outer membrane proteins of Pg301, PgATCC33277 and PgW83 were extracted through ultracentrifugation, and then they were separated by ProteomeLab PF2D protein fractionation system. After separation, the outer membrane proteins were obtained through comparison, and the primary structure of the proteins was identified by MALDI-TOF/TOF-MS and database. RESULTS: Ninety-nine protein samples out of 3 strains of Pg were obtained after the high performance chromato focusing (HPCF) separation process. B7 fractions of 3 strains of Pg were separated by the reversed-phase high performance liquid chromatography (RP-HPCL) separation process. After comparison of peak and retention time of chromatogram, the 8 common protein peaks of 3 strains of Pg were confirmed. The protein samples were identified by MALDI-TOF/TOF-MS, and one of them was known protein arg-gingipain A. CONCLUSIONS: PF2D protein fractionation system is of good reproducibility and high resolution. A combination of PF2D and MALDI-TOF/TOF-MS can be used to identify the common outer membrane proteins of Pg.

[Cloning of the RgpAcd gene of Porphyromonas gingivalis and its expression in E. coli].

OBJECTIVE: To clone the catalytic domain gene sequence of RgpAcd of Porphyromonas gingivalis (P. gingivalis) and to induce its fusion expression in E. coli. METHODS: The desired DNA fragment RgpAcd was obtained by PCR and was separately sequenced and identified by inserting into inter-vector pMD18-T vector. The correctly fragment was linked with and cloned into a prokaryotic expression vector pET-15b. The recombinant expression plasmid which had been confirmed by enzymes digestion was transformed to E. coli competent cells BL21 (DE3) and expression of fusion protein was induced by IPTG. RESULTS: A 1 476 bp specific fragment was obtained and DNA sequencing showed that the fragment was consistent with those of the published. After induction with IPTG, a fusion protein of 5 x 10(4) was visualized on SDS-PAGE gel. CONCLUSION: The protein of RgpAcd will be obtained for further study and its protein was correctly expressed in E. coli BL21 cells.