[Effects of protein kinase C and motigen-activated protein kinase kinase/extracellular regulated protein kinases signaling pathway on mRNA level of inducible nitric oxide synthase in Tca8113 cells].

OBJECTIVE: To explore the regulatory mechanism of inducible nitric oxide synthase (NOS-2) expression related to proliferation of Tca8113 cells. METHODS: RNAi mediated by short hairpin RNAs was utilized to knock down NOS-2, protein kinase C (PKC)-α, PKC-ß and PKC-δ. Griess Reagent played a significant role on the detection of NO product after NOS-2 silence. The cell proliferation was determined by CCK8 method. Quantitative real-time polymerase chain reaction (q-PCR) was recruited to check the mRNA level of NOS-2, PKC-α, PKC-ß and PKC-δ after treated by a variety of ways. Eventually, the measure of phosphorylation of extracellular regulated protein kinases (ERK)1/2 was performed by Western blotting in PMA-treated Tca8113 cells. RESULTS: The cell viability of Tca8113 decreased obviously after transfected with NOS-2 siRNA (P<0.01). PKC reduced the expression level of NOS-2 mRNA (P<0.05). PKC-α, PKC-ß and PKC-δ worked together to regulate the level of NOS-2 mRNA (P<0.01). Motigen-activated protein kinase kinase (MEK)/ERK signaling pathway regulated the level of NOS-2 mRNA negatively (P<0.05). PKC down regulated the level of NOS-2 mRNA through MEK/ERK signaling pathway (P<0.05). CONCLUSIONS: PKC regulates the mRNA level of NOS-2 related to proliferation through MEK/ERK signaling pathway in Tca8113 cells.

Distinctive pathways characterize A. actinomycetemcomitans and P. gingivalis.

The study aimed to compare the molecular mechanism of Porphuromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans). With microarray dataset (GSE9723) from Gene Expression Omnibus, differentially expressed genes (DEGs) were identified comparing normal cell samples with A. actinomycetemcomitans-infected and P. gingivalis-infected periodontitis cell samples, respectively (|logFC| > 1, p value <0.01), followed by hierarchical cluster analysis using Cluster software. Network topological features of A. actinomycetemcomitans-related and P. gingivalis-related protein-protein interaction networks, and background network, which included average shortest path length (ASPL), degree, closeness centrality (CC), eccentricity (EC), betweenness centrality (BC) and topological coefficient (TC) were compared using network analysis plugin of Cytoscape, followed by pathway enrichment analysis (p value <0.05) using FISHER hyper-geometric algorithm and calculation of pathway alter scores using LIMMA. Totally, 839 DEGs and 251 DEGs were screened for A. actinomycetemcomitans and P. gingivalis, respectively. A. actinomycetemcomitans-related network had lower ASPL, degree and EC but higher CC and TC (p < 0.01), while P. gingivalis-related network had lower EC but higher CC and BC (p < 0.01) compared to background network. P. gingivalis-related network had lower ASPL, degree and EC, but higher CC than the A. actinomycetemcomitans-related network (p < 0.05). A. actinomycetemcomitans was associated with the pathways relating to endothelial cells function, while neuroactive ligand-receptor interaction and MAPK pathways were important for P. gingivalis, which had higher alter scores in hematopoietic cell lineage, hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy pathways than A. actinomycetemcomitans. Genes and pathways of the two pathogens were distinctive. The findings aided in preventing and treating relevant diseases.

Improved blood compatibility of Mg-1.0Zn-1.0Ca alloy by micro-arc oxidation.

Magnesium and its alloys have been used in the recent development of lightweight, biodegradeable implant materials. However, the corrosion properties of magnesium limit its usefulness. In a previous study, a micro-arc oxidation (MAO) method was used to modify a Mg-1.0 wt % Zn-1.0 wt % Ca alloy surface, with the purpose of improving the corrosion resistance of Mg alloys. However, the blood compatibility of MAO-treated Mg alloy is unknown. Results of cytotoxicity assays with bone marrow-derived mesenchymal stem cells showed that extracts of MAO-treated alloy significantly decreased cytotoxicity compared to titanium alloy extract. Results of blood compatibility tests showed that the MAO group had a decreased hemolytic ratio (2.25%) compared to the untreated Mg alloy group (24.58%) (p < 0.001). The MAO group showed significantly shorter prothrombin and thrombin times and significantly longer activated partial thromboplastin time than the untreated Mg alloy group. Arachidonic acid- and adenosine diphosphate-induced platelet aggregations were significantly decreased by the untreated Mg alloy extract, and they were less affected by extract of MAO-treated Mg alloy. In conclusion, MAO-treated Mg-1.0 wt % Zn-1.0 wt % Ca alloy exhibits favorable blood compatibility characteristics and may be useful in the development of magnesium implant materials.