Introduction to stem cell models Flashcards
Explain the principal of cellular reprogramming with iPSC technology
Explain how iPSC technology supports Precision Medicine Research
Definition stem cells
- divide through mitosis
- differentiate into diverse specialized cell types
- can self renew to produce more stem cells
Embryonic Stem Cell (ESCs)
Inner cell mass of the blastocyst stage embryo - Pluripotent differentiation
- ESC cultures (1981: 1st mouse ESC line)
- Use for regenerative medicine: * Ethically controversial
* Immune rejection
Explain the difference between totipotent, pluripotent, and multipotent?
Totipotent -> Pluripotent -> Multipotent
Totipotent = can give rise to both the placenta and the embryo
Pluripotent = ability to become all type of cell in the body
Multipotent = several mature cell types
What are the 3 steps in nuclear reprogramming: Methods of inducing pluripotent in somatic cells
1) Cell fusion
2) Nuclear transfer
3) Transcription-factor transduction - induced pluripotent stem (iPS) cells
How do you check iPSCs for pluripotency?
Are they ESC-like?
1) Expression of genes in ESCs?
2) Differentiation into different cell lineages?
3) Epigenetic status of DNA (e.g. methylation of genes)
4) DNA abnormalities (Karyotyping)
5) Formation of teratomas (tumor with tissue or organ components resembling normal derivatives of more than one germ layer)
Name applications of iPSC technology
-Disease modeling
-Drug development -> Precision Medicine
-Cell replacement therapy
- What is the most appropriate phenotype(s) to measure?
- What is the most suitable cell type(s) to study?
Some disease genes have unknown functions.
Well studied genes are involved in multiple pathways - Does a phenotype in a cell model mirrors characteristics of the diseased brain?
E.g. affected neurotransmitter function in vivo, may present as affected migration in vitro. - Are cellular phenotypes meaningful to pathophysiology or prognosis?
What are the advantages of research in iPSC ?
study of
- human cells
- different development stages
- specific cell types
- cellular mechanisms/ pathways
compared to …
- only end stage of disease in post-mortem tissue
- single genetic background in lab mice
- species differences
Challenges in iPSC
- robustness and reproducibility
- ethical considerations
How to use iPSC models to identify pathophysiology and drug targets?
- Simply the genetic change is no good drug target predictor
- Identify the pathways on which te diverse risk factors are likely to converge
- In practice, identify functional endophenotypes in your cell model: downstream abnormalities in pathway responses shared by subgroups of patients despite divergent genetic backgrounds
Endophenotypes: heritable traits that are derived from laboratory measures - Functional cellular endophenotype strategy <->
Traditional target-based approach (gene product)
What are the advantages for iPSC to study rare monogenic neurological disorders?
- can be differentiated to brain cells and allow the study of human specific neurodevelopmental processes
- currently lack of knowledge on disease mechanisms and possible therapeutic options
limited availability of patient tissue and lack of animal models
can be used to study personalized medicine - by making patient specific/ mutation specific iPSC lines
Name and explain the culture systems for iPSC
- Mono cultures
- specific cell types
- iPSCs differentiated into a single cell type to study how this specific cell type is affected by the disease causing mutations - Co-cultures
- cellular interactions
Combining 2 or more different (iPSC-derived) cell types together, to study how cellular interactions contribute to the disease pathomechanisms - Organoid structures
- complex, physiological structures - organoids
In brain organoid structures cells are differentiated to neural cells in a 3D
conformation
* More physiological conformation and cellular composition
