Generation of transgene-free induced pluripotent stem cells with non-viral methods / 中国医学科学杂志(英文版)

Induced pluripotent stem (iPS) cells were originally generated from mouse fibroblasts by enforced expression of Yamanaka factors (Oct3/4, Sox2, Klf4, and c-Myc). The technique was quickly reproduced with human fibroblasts or mesenchymal stem cells. Although having been showed therapeutic potential in animal models of sickle cell anemia and Parkinson's disease, iPS cells generated by viral methods do not suit all the clinical applications. Various non-viral methods have appeared in recent years for application of iPS cells in cell transplantation therapy. These methods mainly include DNA vector-based approaches, transfection of mRNA, and transduction of reprogramming proteins. This review summarized these non-viral methods and compare the advantages, disadvantages, efficiency, and safety of these methods.

Quantitative measurement of in vitro phagocytosis of apoptotic granulosa cells by monocytes in mice / 生理学报

To establish a method for quantitative measurement of phagocytosis, the phagocytic process of apoptotic granulosa cells by monocytes was imitated in vitro. Monocytes and granulosa cells were isolated from Kunming mice and cultured. Granulosa cells were induced to apoptosis by garlic, and then co-cultured with monocytes. At different time points (1 h, 2 h, 3 h, 4 h, 5 h), co-cultured cells were observed by microscope after Wright's staining. The results showed that at the beginning of morphological changes in apoptotic granulosa cells, monocytes captured the apoptotic cells. Meanwhile, the apoptosis of granulosa cells were progressing. Debris was found in phagocytic vacuole. At the point of 3 h after co-culture, the ratio of monocytes which attached to apoptotic granulosa cells to those which engulfed the apoptotic cells was close to one. Namely, half of monocytes were in the state of recognition and half were in the state of engulfment, and this time point was named as 'half phagocytic period'. Regression analysis showed that the equation of linear regression was y = -0.247x +1.644 (y represents Attachment/Engulfment ratio, x represents co-culture time), R(2)=0.912, F=31.095, P=0.011 (<0.05), T= -5.576, P=0.011 (<0.05). In conclusion, the present mode of phagocytosis in vitro can be used as a method to quantitatively assay some effective factors such as medicines which could enhance or restrain phagocytosis.