Effects of Dexamethasone Exposure on Neural Crest Cells and Primary and Secondary Neurulation in Chick Embryos.

AIM: To evaluate the effects of dexamethasone (Dex) treatment on neural crest cells and primary and secondary neurulation in chick embryos. MATERIAL AND METHODS: Sixty fertilized eggs with an average weight of 65 ± 2 g were incubated in 60%?70% humidity at 37.2°C ± 0.1°C. After 26 hours of incubation, the control group (n=12) received 0.1 mg/kg physiologic saline (S), group 1 (n=12) received 0.1 mg/kg Dex, group 2 (n=12) received 1 mg/kg Dex, and group 3 (n=12) received 5 mg/kg Dex into each embryonic disc. The eggs were incubated until Hamburger?Hamilton stage (HH) 15, HH18, and HH20. Then, the embryos were dissected and evaluated both macroscopically and microscopically. RESULTS: The mortality rate in the control group, group 1, and groups 2 and 3 was 27%, 48%, and 100%, respectively. The neural tube thicknesses in group 1 significantly increased in HH 15 and HH20 (p < 0.05). The mitosis number in group 1 significantly decreased in each stage (p < 0.05). Wnt-1 expression was significantly lower in group 1 in HH15 (p < 0.05) and HH18 (p < 0.05), but there was no significant difference in HH20 (p > 0.05). Fibroblast growth factor (FGF) expression was significantly lower in group 1 in HH15 (p < 0.05). The expression of N-cadherin was significantly higher in group 1 in HH20 (p < 0.05). Fibronectin expression decreased in group 1 in HH18 (p < 0.01). CONCLUSION: Although the Dex treatment did not result in neural tube closure defect, the mortality rates and neural tube thicknesses increased, whereas mitotic activation and Wnt-1 and FGF signal pathways reduced in some stages.

The effect of extracellular matrix on the differentiation of mouse embryonic stem cells.

Embryonic stem cells (ESCs) are promising research materials to investigate cell fate determination since they have the capability to differentiate. Stem cell differentiation has been extensively studied with various microenvironment mimicking structures to modify cellular dynamics associated with the cell-extracellular matrix (ECM) interactions and cell-cell communications. In the current study, our aim was to determine the effect of microenvironmental proteins with different concentrations on the capacity and differentiation capability of mouse ESCs (mESCs), combining the biochemical assays, imaging techniques, Fourier transform infrared (FTIR) spectroscopy, and unsupervised multivariate analysis. Based on our data, coating the surface of mESCs with Matrigel, used as an acellular matrix substrate, resulted in morphological and biochemical changes. mESCs exhibited alterations in their phenotype after growing on the Matrigel-coated surfaces, including their differentiation capacity, cell cycle phase pattern, membrane fluidity, and metabolic activities. In conclusion, mESCs can be stimulated physiologically, chemically, or mechanically to convert them a new phenotype. Thus, identification of ESCs' behavior in the acellular microenvironment could be vital to elucidate the mechanism of diseases. It might also be promising to control the cell fate in the field of tissue engineering.

Holistic Approach to Cell Characteristics and Behavioral Analysis.

Cancer is a group of diseases of our era that affects not only medical status but also lowers the tone of social and emotional well-being. It also has severe impacts on economies. Cancer cells are linked to the somatic cells and stem cells, with their characteristic similarities and differences. Variations in cell-signaling pathways, such as cell death and proliferation balances, kinetic behavior of the cells, and their differentiation potentials, are the featured parameters for therapeutic targeting. The detection of target points should be based not only on the molecular biology methods but also on the physical and topological analyses from the aspect of "geography is fate". In this review, we focus on the importance of the holistic analyses of intracellular and extracellular dynamics and multidisciplinary cooperation.