Background: Umbilical cord-derived mesenchymal stem cells (UC-MSCs) are considered to be multipotent mesenchymal stem cells that are easily induced to differentiate into functional osteoblasts both in vitro and in vivo. Osterix (Osx), a novel zinc-⃞nger-containing transcription factor of the Sp family, is required for osteoblast differentiation and bone formation.
Objective: We investigated the effect of Osx on the proliferation and osteogenic differentiation of the UC-MSCs.
Method: The primary UC-MSCs were isolated and cultured. An Osx-expressing plasmid (pEGFP-Osx) was constructed and transfected into UC-MSCs. Then expression of bone morphogenesis-related genes, proliferation rate, alkaline phosphatase activity, and mineralization were examined to evaluate the osteogenic potential of the Osx gene-modified UC-MSCs.
Result: UC-MSCs transfected with pEGFP-Osx exhibited apparent osteogenic differentiation as determined by increased activity of alkaline phosphatase, the formation of mineralized nodules and the expression of related osteoblastic genes.
Conclusion: These results confirmed the ability of Osx to enhance osteoblast differentiation of UC-MSCs in vitro, and the Osx gene-modified UC-MSCs are potential as novel cell resources of bone tissue engineering.
Peng Zhang, Chunli Liu, Shanshan Song and Chifang Peng
A novel method of immobilizing horse radish peroxidase enzyme (HRP) onto the surface of gold nanoparticles (GNPs) was developed. As a result, a high-activity bionanoconjugates was obtained through utilizing the biotin-streptavidin (SA) system. The HRP-SA-GNP bionanoconjugate with high activity was conveniently prepared through the biotin- avidin system. Compared with the HRP-GNP bioconjugate prepared through the traditional electrostatic absorption method, the enzyme activity per GNPs of this new bionanoconjugate was enhanced by 10 times. Moreover, the enzyme activity of this bionanoconjugate was controllable. The above method of bionanoconjugation preparation has promising applications in the fields including preparing highly active bio-nanoprobe and immobilized enzyme.
Jinwei Luan, Xianglan Li, Rutao Guo, Shanshan Liu, Hongyu Luo and Qingshan You
Next generation sequencing and bio-informatic analyses were conducted to investigate the mechanism of reactivation of p53 and induction of tumor cell apoptosis (RITA)-enhancing X-ray susceptibility in FaDu cells.
Materials and methods
The cDNA was isolated from FaDu cells treated with 0 X-ray, 8 Gy X-ray, or 8 Gy X-ray + RITA. Then, cDNA libraries were created and sequenced using next generation sequencing, and each assay was repeated twice. Subsequently, differentially expressed genes (DEGs) were identified using Cuffdiff in Cufflinks and their functions were predicted by pathway enrichment analyses. Genes that were constantly up- or down-regulated in 8 Gy X-ray-treated FaDu cells and 8 Gy X-ray + RITA-treated FaDu cells were obtained as RITA genes. Afterward, the protein-protein interaction (PPI) relationships were obtained from the STRING database and a PPI network was constructed using Cytoscape. Furthermore, ClueGO was used for pathway enrichment analysis of genes in the PPI network.
Total 2,040 and 297 DEGs were identified in FaDu cells treated with 8 Gy X-ray or 8 Gy X-ray + RITA, respectively. PARP3 and NEIL1 were enriched in base excision repair, and CDK1 was enriched in p53 signaling pathway. RFC2 and EZH2 were identified as RITA genes. In the PPI network, many interaction relationships were identified (e.g., RFC2-CDK1, EZH2-CDK1 and PARP3-EZH2). ClueGO analysis showed that RFC2 and EZH2 were related to cell cycle.
RFC2, EZH2, CDK1, PARP3 and NEIL1 may be associated, and together enhance the susceptibility of FaDu cells treated with RITA to the deleterious effects of X-ray.
Lin Wang, Fengna Xue, Wenbang Gao, Jing Shi, Shanshan Sun, Junxiu Liu, Rina Su, Yunhu Xie, Chunxing Hai and Li Xiaojia
Protection of the environment by returning farmland to forest and grassland through enclosing areas of land to permit regeneration of native flora is being implemented in the Loess hill region of China. Soil physical properties are important components of ecological systems, as comparisons between cultivated and enclosed areas demonstrate. The results showed: the soil moisture content in the enclosed area was 14.6% and that in the cultivated area was 14%; the soil bulk density and soil porosity were respectively 1.45 g/cm3 and 45.28% in the enclosed areas, and respectively 1.46 g/cm3 and 44.79% in cultivated land. The alteration of soil physical properties was not big between cultivated areas and enclosed areas in the short term.