AIM:To study the viscoelastic properties of human hepatocytes and hepatocellular carcinoma (HCC) cells under cytoskeletal perturbation, and to further to study the viscoelastic properties and the adhesive properties of mouse hepatoma cells (HTC) in different cell cycle. METHODS:Micropipette aspiration technique was adopted to measure viscoelastic coefficients and adhesion force to collagen coated surface of the cells. Three kinds of cytoskeleton perturbing agents, colchicines (Col), cytochalasin D (CD) and vinblastine (VBL), were used to treat HCC cells and hepatocytes and the effects of these treatment on cell viscoelastic coefficients were investigated. The experimental results were analyzed with a three-element standard linear solid. Further, the viscoelastic properties of HTC cells and the adhesion force of different cycle HTC cells were also investigated. The synchronous G1 and S phase cells were achieved through thymine-2-desoryriboside and colchicines sequential blockage method and thymine-2-desoryriboside blockage method respectively. RESULTS:The elastic coefficients, but not viscous coefficient of HCC cells (K 1 =103.6±12.6N.m -2

Aim: To investigate whether bone morphogenic protein-2 (BMP-2) expression was involved in calcitonin gene-related peptide (CGRP)-induced osteogenesis in human osteoblast-like cells in vitro. Methods: MG-63 osteogenic human osteosarcoma cells were treated with CGRP (10 -8 mol/L) for 48 h. Cell cycle phases were determined using flow cytometry assay. The protein levels of BMP-2, ALP, Osteocalcin, ColIa1, CREB, and pCREB were measured with Western blotting, while the mRNA level of BMP-2 was measured with qR-T PCR. The expression of ALP in MG-63 cells was also studied using immunofluorescence staining. The level of cAMP was measured with ELISA assay. Results: CGRP treatment significantly stimulated proliferation of MG-63 cells, and increased the expression of BMP-2 and the osteogenic proteins ALP, Osteocalcin and ColIa1. Pretreatment with the BMP signaling inhibitor Noggin (100 ng/mL) did not affect CGRPstimulated proliferation and BMP-2 expression, but abolished the CGRP-induced increases of the osteogenic proteins ALP, Osteocalcin and ColIa1. Furthermore, CGRP treatment markedly increased cAMP level in MG-63 cells, whereas pretreatment with the cAMP pathway inhibitor H89 (5 μmol/L) abolished the CGRP-induced increases of cAMP level and BMP-2 expression. Conclusion: In MG-63 cells, the BMP pathway is involved in CGRP-induced osteogenic differentiation but not in proliferation, whereas the cAMP/pCREB pathway is involved in the expression of BMP-2.Keywords: c calcitonin gene-related peptide; Noggin; H89; MG-63 human osteosarcoma cell; osteogenesis; bone morphogenic protein; cAMP/pCREB pathway Acta Pharmacologica Sinica (2013Sinica ( ) 34: 1467Sinica ( -1474 doi: 10.1038/aps.2013 published online 27 May 2013 Original Article IntroductionSensory nerve activation has a centrally mediated but poorly understood action on bone. The relative importance and interactions between autonomic, sensory, and peripheral nervous system actions on bone mass are not clear in healthy individuals and even less so in pathologic states. Understanding how the central nervous system integrates homeostatic signals with the regulation of bone homeostasis is an exciting research area.Experimental evidence suggests that the nervous system is involved in bone remodeling. In response to fracture or other trauma, peripheral peptidergic neurons can influence osteoclast formation through the production of several neuropeptides. Calcitonin gene-related peptide (CGRP), a 37-residue peptide generated in specific neurons by alternative splicing of the calcitonin gene, is an important neuropeptide expressed * To whom correspondence should be addressed.E-mail tanyhoms@yahoo.cn Received 2012-10-30 Accepted 2013-03-25 in nerve fibers during bone development and repair [1,2] .Numerous in vivo studies have suggested that CGRP is associated with bone development, metabolism and repair. In vitro studies have demonstrated that CGRP stimulates osteoblast proliferation, differentiation and maturation in both osteoblast cell lines and bone marrow mesenchyme strom...

Periodontitis is a chronic inflammatory disease characterized by the destruction of tooth supporting tissues. Hypoxia, the mainly changes of the plateau environment, can induce severe periodontitis by animal experiments. There is, however, very little information on hypoxia and lipopolysaccharide (LPS) induced cytokine expression in periodontal ligament (PDL) cells. In this article, we characterized hypoxia or P. gingivalis lipopolysaccharide (Pg LPS) induced tumor necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6 expression by human periodontal ligament (hPDL) cells. We found that hypoxia augmented Pg LPS induced TNF-α, IL-1β, and IL-6 expression in hPDL cells. We also demonstrated that nuclear factor kappa B pathway was involved in hypoxia augmenting Pg LPS induced cytokine expression in hPDL cells. Thus, our results suggest that the hypoxic environment may enhance the immune function of hPDL cells that is induced by Pg LPS.

Human bone mesenchymal stem cells (hMSCs) can differentiate into endothelial cells (ECs), so we aimed to investigate whether hMSCs could also differentiate into a specific arterial or venous ECs. hMSCs were induced to differentiate into ECs using vascular endothelial growth factor (VEGF). Low VEGF concentration (50 ng/ml) upregulated the venous marker gene EphB4, however high concentration (100 ng/ml) upregulated the arterial marker genes ephrinB2, Dll4 and Notch4, and downregulated the venous marker genes EphB4 and COUP-TFll. This VEGF dose-dependent induction was largely blocked by inhibition of the Notch pathway in hMSCs treated with c-secretase inhibitor. Therefore, differentiation of hMSCs into arterial-or venous-specific ECs depends on VEGF and is regulated by the Notch pathway.