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In this paper, we established a calcium dynamics model of fibroblast-like synoviocytes (FLS). A set of parameters was given for describing [Ca2+]; changes of FLS stimulated by capsacin(CAP). The model consists of several modules, including calcium pump in the plasma membrane, calcium pump and calcium leak in the ER, IP3 receptor, Na+/K+ pump, the delayed rectifier potassium channel(Kv), TRPV1 channel etc. . According to the model, the interaction between [Ca2+]i and Vm plays an important role in the [Ca2+],- dynamics of FLS. Conclusions; It is necessary to include IP3 receptor module which contains biphasic regulation mechanism for building model. The interaction between [Ca2+]; and Vm plays an important role in the [Ca2+]; dynamics of FLS. Some of the physiological characteristic of FLS, such as the density of calcium pump in the plasma membrane and ER, the density of IP3R channel in ER and TRPV1 channel in the plasma membrane, the activity of ER calcium leak related protein, the concentration of calcium buffering proteins etc. have impacts on the shape of the calcium dynamic curves. [ABSTRACT FROM AUTHOR]

Visualizing the plasma membrane of living mammalian cells both in vitro and in vivo is crucial for tracking their cellular activities. However, due to the complex and dynamic nature of the plasma membrane, most commercial dyes for membrane staining can only realize very limited imaging performance. Thus, precise and stable plasma membrane imaging remains technically challenging. Here, by taking advantage of the small, well-defined, and amine-rich dendrimers, we prepared poly(ethylene glycol)-cholesterol (PEG-Chol)-conjugated and cyanine dye (e.g., cyanine2, cyanine3, and cyanine5)-labeled dendrimer nanoprobes (termed DPC-Cy2, DPC-Cy3, and DPC-Cy5 NPs). It was revealed that these probes enabled universal, wash-free, long-term (at least 8 h), and multicolor (green, yellow, and red) plasma membrane labeling of a variety of live mammalian cells. Further, we confirmed that the nanoprobes (using DPC-Cy5 as a representative) could achieve high-quality, wash-free, and stable cell surface labeling of live zebrafish embryos. More importantly, we demonstrated that our probes could act as biosensors to visualize the toxicity of metal – organic frameworks (MOFs) toward the epidermal cells of zebrafish embryos, and thus they hold great potential for identifying the toxic effect of drugs/materials at the single-cell scale or in live animals. The present work highlights the advantages of utilizing dendrimers for constructing functional imaging materials, and it is also believed that the fluorescent dendrimer nanoprobes developed in this work may find wide applications like cell imaging, drug toxicity evaluation, and cellular state monitoring. [Display omitted] [ABSTRACT FROM AUTHOR]

• Up-regulation of Rac1 can enhance the sensitivity of human poorly differentiated NPC CNE2 cells to radiation. • Oxidative damage of mitochondria induce by Rac1 may be a key mechanism of radiosensitization. • A new way for promoting the efficiency of radiotherapy by target regulation of Rac1 protein. Radiotherapy has a high cure rate for early nasopharyngeal carcinoma(NPC). However, the radiation resistance of poorly differentiated NPC cells impacts the effectiveness of treatment of early-stage NPC patients. Here, we explored the relationship between Ras-related C3 botulinum toxin substrate 1(Rac1) expression and NPC radiosensitivity. In vitro and in vivo studies revealed that upregulation of Rac1, when combined with X-ray treatment, increased growth inhibition and induced remarkable morphological changes and apoptosis in CNE2 cells. Furthermore, rupturing of the cell and nuclear membranes, degeneration of the cristae and significant swelling of the mitochondria were observed, which were consistent with the high apoptotic rate. The Rac1(+) cells exhibited approximately 50% more migration compared with that of the NC and Rac1(-) cells. The overexpression of Rac1 can increase the radiation sensitivity of NPC CNE2 cells, and the mechanism may be closely related to the oxidative damage of mitochondria. Rac1 might be a potential target for radiosensitization in poorly differentiated NPC. Image, graphical abstract [ABSTRACT FROM AUTHOR]