摘要: Objectives Synthetic oligonucleotides have shown promise in brain imaging. However, delivery of oligonucleotides into live brain cells remains challenging. In this study, we aim to develop a facile yet efficient strategy for local delivery of oligodeoxynucleotide (ODN) to neural cells in live adult mouse brain. Materials and methods A fluorescence-labelled ODN was diluted with sodium citrate buffer (100 mmol/L, pH = 3). One microlitre of the mixture was injected into a live adult mouse brain. Six hours later, we sacrificed the mouse and prepared brain slices for microscopic imaging. Results We find that the use of sodium citrate buffer in the one-shot local delivery can improve the diffusion and cell entry efficiency of the unmodified ODN for dozens of times. Only 1 pmol ODN leads to hundreds of positively transferred brain cells. We reason that this promotion is due to the local acidic condition created by the citrate buffer, which leads to the protonation of the ODN and some membrane proteins, thus reduces the Coulomb repulsion between the ODN and the cell membrane. Based on this strategy, we demonstrate fluorescent microscopic imaging of brain cells in different brain regions including striatum, cortex, hippocampus and midbrain. Conclusions The citrate buffer can be used as an adjuvant for facile and effective local injection delivery of ODNs, which may provide a new tool for brain imaging.

摘要: Objectives Exposure to microgravity induces many adaptive and pathological changes in human bone marrow mesenchymal stem cells (hBMSCs). However, the underlying mechanisms of these changes are poorly understood. We revealed the gene expression patterns of hBMSCs under normal ground (NG) and simulated microgravity (SMG), which showed an interpretation for these changes by gene regulation and signal pathways analysis. Materials and methods In this study, hBMSCs were osteogenically induced for 0, 2, 7 and 14 days under normal ground gravity and simulated microgravity, followed by analysis of the differences in transcriptome expression during osteogenic differentiation by RNA sequencing and some experimental verification for these results. Results The results indicated that 837, 399 and 894 differentially expressed genes (DEGs) were identified in 2, 7 and 14 days samples, respectively, out of which 13 genes were selected for qRT-PCR analysis to confirm the RNA-sequencing results. After analysis, we found that proliferation was inhibited in the early stage of induction. In the middle stage, osteogenic differentiation was inhibited, whereas adipogenic differentiation benefited from SMG. Moreover, SMG resulted in the up-regulation of genes specific for tumorigenesis in the later stage. Conclusion Our data revealed that SMG inhibits the proliferation and inhibits the differentiation towards osteoblasts but promotes adipogenesis. SMG also selects highly tumorigenic cells for survival under prolonged SMG.