Bilineage embryo-like structure from EPS cells can produce live mice with tetraploid trophectoderm

Self-organized blastoids from extended pluripotent stem (EPS) cells possess enormous potential for investigating postimplantation embryo development and related diseases. However, the limited ability of postimplantation development of EPS-blastoids hinders its further application. In this study, single-cell transcriptomic analysis indicated that the "trophectoderm (TE)-like structure" of EPS-blastoids was primarily composed of primitive endoderm (PrE)-related cells instead of TE-related cells. We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure. Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation. Furthermore, we demonstrated that blastocyst-like structures reconstituted by combining the EPS-derived bilineage embryo-like structure (BLES) with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses. In summary, our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.

Influencing factors of geometrical accuracy in magnetic resonance imaging for gamma knife radiosurgery / 中华放射医学与防护杂志

Objective To evaluate and improve the geometrical accuracy of the magnetic resonance imaging used for gamma knife radiosurgery localization. Methods Four common MRI scan programs were used in this study. The images were transferred to the Gamma Plan treatment planning system.Deviations between stereotactic coordinates based on MR images and real geometrical positions given by the construction of the phantom insert were evaluated for each study.The deviations were further investigated as a function of the spatial position of measured points in the investigated volume.Results The geometrical coordinate errors for axial and coronal images of the selected scan programs were all less than 1 mm.Optimal imaging procedure in terms of geometrical accuracy was observed using spin echo T1 and 3D FSPGR MRI sequences in the unit.Statistically significant differences were found in axial images amongSE T1,FSE T2,FRFSE Pd,FSPGR 3D sequences (F=1497.51,1873.63,2.87,3.00,P ＜0.05).The error increased along with the increase of the distance between node point and centricity.Conclusions The geometrical coordinate errors is related with the imaging program in M(il)l. Proper imaging programs and parameters should be selected according to the imageology character of patients' lesions when the radiosurgery is performed.

Construction and expression of siRNA expression constructs targeting epidermal growth factor receptor / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To construct the small interfering RNA (siRNA) expression constructs targeting epidermal growth factor receptor(EGFR) and express them in TJ905 human malignant cells.</p><p><b>METHODS</b>Two target sequences from Receptor L domain and catalytic domain were selected to create two expression constructs using psiRNA-NeoG2. Furthermore, the siRNA constructs were transfected into TJ905 cells as mediated by Lipofectamin. Meanwhile, an antisense EGFR construct p-anti-hEGFR was set as control. Immunofluorescence and Western blot were performed to detect EGFR expression.</p><p><b>RESULTS</b>With the successful construction of the two siRNA expression plasmids and the stable transfection to TJ905 cells, the expression of EGFR was down-regulated to 90% and 92% respectively, but to 82% in the anti-sense EGFR group.</p><p><b>CONCLUSION</b>The siRNA expression constructs targeting EGFR could specifically inhibit EGFR expression, and should be a new strategy in glioma gene therapy targeting EGFR.</p>