Independent publication cites use of the CoolCell freezing container for cryopreservation of human neuronal progenitor and stem cells.
Despite a centuries-old fascination with the brain, we have a relatively thin grasp on how the brain works. President Obama recently announced a new initiative to try to tackle the problem, which the NIH is calling the Brain Activity Map, to be funded by $3 billion over the next ten years. The idea is that a map of the connections in the human brain might help us better understand diseases like Alzheimer’s, schizophrenia, and Parkinson’s. As people consider how best to study the brain, one avenue that scientists have been chipping away at is to use stem cells to model the brain’s connections, in vitro.
This can be accomplished by differentiating human embryonic stem cells (hESC) or induced pluripotent stem cells (iPSC) into neurons through directed differentiation. Developing the technology to do this in vitro has broad utility: differentiated stem cells could be used to model disease in a dish, or be developed for neuronal transplantation. Also, in vitro human neuronal stem cell models might someday trump the mouse models of human disease currently used in the lab because they are more relevant to the human condition.
Until recently, scientists have had a hard time driving stem cells down a path that completely recapitulates that of normal neuronal development. The cultures failed to produce all cortical cell types. A recently published protocol describes a method for differentiating both embryonic stem cells and iPSCs into all types of human neuronal progenitor cells and cerebral cortex neurons.
Differentiating stem cells into neurons is time and labor intensive. It takes three weeks to prepare stem cells for induction, two weeks to induce the cells, and a further three weeks to expand and differentiate neural stem cells. Once differentiated, cultures can be maintained for up to 3 months for study in the lab. However, they cannot be further passaged, meaning that cultures have an “expiration date” for study.
Fortunately, it is possible to cryopreserve established cortical neuronal stem cells before they terminally differentiate. The published protocol endorses the use of the CoolCell freezing container to do so. Rosettes of cells undergoing neurogenesis can be dissociated into single cell suspensions, frozen in cryovials using the CoolCell, and stored in liquid nitrogen. They can be thawed and shared as needed, furthering both the reproducibility of science and our understanding of the human brain.
1. Y. Shi et al. Directed differentiation of human pluripotent stem cells to cerebral cortex neurons and neural networks. Nature Protocols. 2012 Oct;7(10):1836-46. doi: 10.1038/nprot.2012.116.