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101.
《Cell calcium》2019
Bone morphogenetic protein-2 (BMP-2) promotes the differentiation of non-osteogenic mesenchymal cells to osteogenic cells. In this study, we isolated human adipose-derived stem cells (hASCs) and investigated the effects of recombinant human BMP-2 (rhBMP-2) and extracellular Ca2+ concentration ([Ca2+]out) on the osteogenic differentiation of hASCs. rhBMP-2 promoted calcium deposition in hASCs and stimulated the mRNA expressions of six proteins known to be involved in the osteogenic differentiation of hASCs: Runx2, osterix, alkaline phosphatase, osteonectin, bone sialoprotein and osteocalcin. Elevation of [Ca2+]out enhanced the level of alkaline phosphatase enzyme, increased the mRNA expressions of Runx2 and osteocalcin and induced the expressions of BMP-2 mRNA and protein in hASCs. Elevation of [Ca2+]out transiently increased the intracellular Ca2+ concentration ([Ca2+]in) due to activation of the calcium-sensing receptor (CaSR). The Ca2+-induced expressions of BMP-2 mRNA and protein were inhibited by the calmodulin antagonist, W-7. Furthermore, elevation of [Ca2+]out decreased the cytoplasmic level of phosphorylated nuclear factor of activated T-cell-2 (NFAT-2) and increased the nuclear level of dephosphorylated NFAT2. Taken together, these results suggest that rhBMP-2 promotes the osteogenic differentiation of hASCs. Furthermore, an increase in [Ca2+]out enhances the expression of BMP-2 via activation of the CaSR, elevation of [Ca2+]in and stimulation of Ca2+/calmodulin-dependent NFAT-signaling pathways. 相似文献
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Pedro J. I. Salas Dora E. Vega-Salas Enrique Rodriguez-Boulan 《The Journal of membrane biology》1987,98(3):223-236
Summary Madin-Darby canine kidney (MDCK) cells kept in suspension culture for 12–15 hr displayed high-affinity binding sites for125I-lathyritic (soluble) collagen (120,000/cell,K
D
=30nm) and preferred collagens types I and IV over laminin or fibronectin as substrates during the first hour of attachment. On the other hand, after 4 hr, attachment to all four substrates was equally efficient. Upon challenge with a collagen substrate, the high-affinity sites were rapidly recruited on it (T1/2=6 min). Their occupancy by soluble collagen triggered the exocytosis of a second large population of low-affinity collagen binding sites that included laminin and seems to be involved in a second cell-attachment mechanism. These results are compatible with a twostep model of MDCK cell attachment to the substrate: first, via high-affinity collagen binding sites, and second, via laminin of cellular origin. 相似文献
109.
Amjad Islam Jianguo Li Muhammad Pervaiz Zheng‐Hong Lu Mohini Sain Lihui Chen Xinhua Ouyang 《Liver Transplantation》2019,9(10)
Zwitterions, a class of materials that contain covalently bonded cations and anions, have been extensively studied in the past decades owing to their special features, such as excellent solubility in polar solvents, for solution processing and dipole formation for the transfer of carriers and ions. Recently, zwitterions have been developed as electrode modifiers for organic solar cells (OSCs), perovskite solar cells (PVSCs), and organic light‐emitting devices (OLEDs), as well as electrolyte additives for lithium ion batteries (LIBs). With the rapid advances of zwitterionic materials, high‐performance devices have been constructed with enhanced efficiencies by introducing them as interface layers and electrolyte additives. In this review, recent progress in OSCs, PVSCs, OLEDs, and LIBs by using zwitterions is highlighted. The authors also elaborate the role of various zwitterionic materials as interfacial layers and additives for highly efficient OSCs, PVSCs, OLEDs, and LIBs. This article presents an overview of device performance of zwitterionic materials. The structure–property relationship is also discussed. Finally, the prospects of zwitterion materials are also addressed. 相似文献
110.
Electron-microscopic and immunocytochemical analyses of Weibel-Palade bodies in the human umbilical vein during pregnancy 总被引:3,自引:0,他引:3
Summary The present study was done to elucidate the biological significance of the Weibel-Palade body of human umbilical vein endothelial cells. Quantitative determinations of these endothelial-specific granules throughout pregnancy revealed that their numbers and size per cell profile were maintained at low levels from 12 to 19 weeks of gestation; then both rapidly increased from 33 weeks to full term. This increase coincided with the development of the rough endoplasmic reticulum and an increase in the number of endothelial cell pinocytotic vesicles. Light-microscopic peroxidase anti-peroxidase and electron-microscopic protein A-gold techniques provided evidence that factor VIII-related antigen was localized in the Weibel-Palade bodies. Furthermore, in vitro treatment of incubated umbilical vein tissue with compound 48/80, a histamine releaser, induced degranulation of Weibel-Palade bodies from the endothelium. The present study indicates that Weibel-Palade bodies are storage sites of both histamine and factor VIII-related antigen and have an important role in the obliteration of this vessel. 相似文献