Sox-positive cell population in the adult cerebellum increases upon tissue degeneration.

Adult neurogenesis is well-described in the subventricular and subgranular zones of the mammalian brain. Recent observations that resident glia express stem cell markers in some areas of the brain not traditionally associated with neurogenesis hint to a possible role in tissue repair. The Bergmann glia (BG) population in the cerebellum displays markers and in vitro features associated with neural stem cells (NSC), however the physiological relevance of this phenotypic overlap remains unclear in the absence of established in vivo evidence of tissue regeneration in the adult cerebellum. Here, this BG population was analysed in the adult cerebellum of different species and showed conservation of NSC-associated marker expression including Sox1, Sox2 and Sox9, in chick, primate and mouse cerebellum tissue. NSC-like cells isolated from adult mouse cerebellum showed slower growth when compared to lateral ventricle NSC, as well as differences upon differentiation. In a mouse model of cerebellar degeneration, progressive Purkinje cell loss was linked to cerebellar cortex disorganisation and a significant increase in Sox-positive cells compared to matching controls. These results show that this Sox-positive population responds to cerebellar tissue disruption, suggesting it may represent a mobilisable cellular resource for targeted strategies to promote tissue repair.

Magnetically Assisted Control of Stem Cells Applied in 2D, 3D and In Situ Models of Cell Migration.

The success of cell therapy approaches is greatly dependent on the ability to precisely deliver and monitor transplanted stem cell grafts at treated sites. Iron oxide particles, traditionally used in vivo for magnetic resonance imaging (MRI), have been shown to also represent a safe and efficient in vitro labelling agent for mesenchymal stem cells (MSCs). Here, stem cells were labelled with magnetic particles, and their resulting response to magnetic forces was studied using 2D and 3D models. Labelled cells exhibited magnetic responsiveness, which promoted localised retention and patterned cell seeding when exposed to magnet arrangements in vitro. Directed migration was observed in 2D culture when adherent cells were exposed to a magnetic field, and also when cells were seeded into a 3D gel. Finally, a model of cell injection into the rodent leg was used to test the enhanced localised retention of labelled stem cells when applying magnetic forces, using whole body imaging to confirm the potential use of magnetic particles in strategies seeking to better control cell distribution for in vivo cell delivery.