One-pot synthesis of compact DNA silica particles for gene delivery and extraordinary DNA preservation

Repairing genetic defects using exogenous DNA is a major challenge the science is currently facing. This requires the design of vectors that can effectively encapsulate, protect and target nucleic acids to specific cells safely and precisely. Here we have designed silica-based physiologically responsive particles to encapsulate, store, and transfer DNA. Unlike existing vectors (e.g., viral or lipidic particles), these DNA@SiO2 systems are very stable at room temperature. We also demonstrate how they protect the encapsulated DNA from exposure to different biological and physicochemical stresses, including DNase, denaturation temperatures (>100 °C), or reactive oxygen species (ROS). Remarkably, upon cellular uptake, these vectors dissolve safely unpacking the DNA and transfecting the cells.The versatility of the design is such that it can encapsulate genes without gene/size restrictions, in single or multiple layers of silica, so different genes can be expressed sequentially. This allows the time-controlled transcription of several genes, mimicking viral gene expression cascades, or even “fine-tuning” gene expression in transfected cells on demand. In addition, the method is easily scalable, reproducible, and inexpensive, enabling large-scale production and batch-quality testing, all of which are important for the personalized therapeutics industry. The high stability of these DNA vectors allows for easy and low-cost transport from the point of production to virtually any destination, making them unique as gene delivery tools

Oligodendrocyte development and differentiation in the rumpshaker mutation

The jimpy rumpshaker (jprsh) mutation is an amino acid substitution in exon 4 (Ile186[RIGHTWARDS ARROW]Thr) of the proteolipid protein (PLP) gene on the X chromosome. Affected mice show moderate hypomyelination of the central nervous system (CNS) with increased numbers of oligodendrocytes in the white matter of the spinal cord, a feature distinguishing them from other PLP mutations such as jp, in which premature cell death occurs with reduced numbers of oligodendrocytes. Myelin sheaths of jprsh immunostain for myelin basic protein (MBP) and DM-20, but very few contain PLP. This study examines the differentiation of oligodendrocytes cultured from the spinal cords of young mutant and wild type mice using various surface and cytoplasmic antigenic markers to define the stage of development. The majority of oligodendrocytes from mutant mice progress normally to express MBP; approximately 30%, relative to wild type, contain DM-20 at the in vivo age of 16 days, but very few immunostain for PLP or the O10 and O11 markers. The morphology of mutant cells in respect to membrane sheets and processes appears similar to normal. The jprsh oligodendrocyte is, therefore, characterized by a failure to express the markers indicative of the most mature cell; however, it is probably able to achieve a normal period of survival. These data, taken in conjunction with previous results, suggest that the PLP gene has at least two functions; one, probably involving PLP, is concerned with a structural role in normal myelin compaction; the other, perhaps related to DM-20 (or another lower molecular weight proteolipid), is essential for cell survival. The mutation in jprsh at residue 186 suggests that this region, which is common to PLP and DM-20, is not critical for this latter function