Artificial Cells for Cellular Behavior Mimicry Induced by Sphingomyelin Degradation.

Sphingomyelinase (SMase), a hydrolase of sphingomyelin (SM) enriched in the outer leaflet of the plasma membrane of mammalian cells, is closely associated with the onset and development of many diseases, but the specific mechanisms of SMase on the cell structure, function, and behavior are not yet fully understood due to the complexity of the cell structure. Artificial cells are minimal biological systems constructed from various molecular components designed to mimic cellular processes, behaviors, and structures, which are excellent models for studying biochemical reactions and dynamic changes in cell membranes. In this work, we presented an artificial cell model that mimics the lipid composition and content of the outer leaflet of mammalian plasma membranes for studying the effect of SMase on cell behavior. The results confirmed that the artificial cells can respond to SM degradation by producing ceramides that enrich and alter the membrane charge and permeability, thus inducing the budding and fission of the artificial cells. Thus, the artificial cells developed here provide a powerful tool to study the mechanism of action of cell membrane lipids on cell biological behavior, paving the way for further molecular mechanism studies.

[Nifedipine regulated expression of bcl-2 in human gingival epithelial cells in vitro].

PURPOSE: To investigate the effect of nifedipine(NIF) on transcription of bcl-2 in human gingival epithelial cells(HGECs) in vitro and to study the pathogenesis of epithelial thickening in drug-induced gingival overgrowth(DGO). METHODS: The gingival tissues obtained from periodontal surgeries were digested with enzyme and HGECs were cultured in vitro; HGECs were identified by immunohistochemistry; bcl-2 mRNA levels were quantitated by Real-time PCR 24 hours and 48 hours after cells stimulated by NIF with different concentration (0microg/ml, 1microg/ml,2microg/ml,3microg/ml), in which 0microg/ml NIF as blank control. The data was analyzed by one-way ANOVA using SPSS 11.0 software package. RESULTS: HGECs cultured in vitro showed keratin positive signal and vimentin negative signal; the level of bcl-2 mRNA increased with NIF 3microg/ml after 24 hours treatment, which appeared significant increase compared with blank control (P<0.05); after 48 hours treatment the level of bcl-2 mRNA in the groups of 2microg/ml and 3microg/ml showed significant increase compared with blank control (P<0.05). CONCLUSION: NIF regulates the level of bcl-2 mRNA.

[Amelogenin expression in cultured human dental pulp and periodontium related cells].

PURPOSE: To investigate gene expression of amelogenin (Am) in human gingival epithelial cells(HGEC) and also other oral ectomesenchyme cells (human gingival fibroblasts, human periodontal ligament fibroblasts and human pulp cells). METHODS: The amelogenin mRNA expression patterns were determined by the reverse transcription polymerase chain reaction (RT-PCR),and the protein expression was studied with Western blotting. RESULTS: There was no amelogenin expression detected in any of the cells. CONCLUSIONS: These findings suggest that amelogenin expression could not be detected in cultured human periodontium-related cells. Supported by National Natural Science Foundation of China (Grant No.30672315) and Research Fund of Science and Technology Commission of Shanghai Municipality(Grant No.08DZ2271100).