Lecture 32 Flashcards
Which cells can be cultured and used to create a population of embryonic stem cells
Cells of the inner cell mass of the blastocyst
What type of cells do tissue specific/adult stem cell give rise prior to specialising and what is distinct about these cells
Adult stem cells give rise to transient amplifying progenitor cells what amplify in number. These are multipotent cells that are committed to a certain lineage and divide rapidly. However these cells aren’t capable of self-renewal and have limited potency
What is meant by a stem cell niche
The microenvironment around a stem cell that provides support and signals regulating self-renewal and differentiation. This can be either through direct contact with the stem cell or through the action of secreted factors
What are iPS cells
Induced pluripotent stem (iPS) cells are cells that are derived from fully differentiated cells but have been induced to pluripotent fate
Give an example of a genetic marker specific for motor neurons
Hb9 transcription factor
Explain the implications of John Gurdon’s’ nuclear transfer experiments in Xenopus on the field of stem cell research
Gurdon took large egg cells from Xenopus and removed the nucleus. A nucleus from a fully differentiated cell of a tadpole was injected into the enucleated egg cell. The hybrid cell began to develop into an organism genetically identical to the tadpole it had come from. That meant that the nucleus from a fully differentiated cell only expressing certain genes switched back to more potent cell before developing to give rise to a clone of the organism from which it was derived. Hence the DNA introduced must have been reprogrammed to a pluripotent fate by something in the cytoplasm
What is the mechanism by which fully differentiated cells can be reverted to a pluripotent state
Cytoplasmic egg factors activate transcription factors in the differentiated cell, that sit at the top of a hierarchy of de-differentiation and return to pluripotency
What was the role of Yamanaka in the discovery of iPS cells
Yamanaka identified the four transcription factors required to return a cell to pluripotency (OCT4, SOX2, c-Myc and KLF4)
How were the transcription factors identified that were required to return a cell to pluripotency
These transcription factors were identified from a number of transcription factors known to be expressed by pluripotent cells but that were transcriptionally shut down as they differentiate
What is the major advantage of using iPS cells for research
They don’t involve nor require embryos and so the ethical questions are minimised
Give examples of the clinical applications of iPS cells
Drug screening, disease modelling, personalised and/or non-immunogenic medicine
iPS cells are vastly renewable and easily accessible, T or F
T
How are iPS cells currently being used to understand development and disease
Being used to develop and grow human organoids in order to act as disease models and screen drugs etc.
Give an example of where iPS cells have been used in the understanding of disease
iPS cells are being directed to lung cells and are being cultured on sophisticated tissue engineered substrates – lung-on-chip
iPS cells have more recently been used to create brain organoids, where are the stem cells found in these structures
Near to the ventricles/lumen
