Neural stem cells (Dr. Yuzwa session Flashcards
What is unipotent stem cells?
only produces one cell type, like germline stem cells making sperms
When does stem cells transition from pluripotent to multipotent?
once organogenesis occur (around E8.5)
Order the amount of cell types that stem cells can differentiate (the most to the least)
Totipotent > pluripotent > multipotent > unipotent or precursor cells
What can pluirpotent stem cells produce？
all cells of animal except embryonic tissue
What cells can totipotent cells produce?
all cells, including extra embryonic tissues like placenta, umbilical cord
How are stem cells restricted to certain cell fates?
with epigenetic marks
–> once marked, transcription factor cannot bind so these genes are silenced
Relationship between cell division and differentiation
more differentiated –> less likely to divide
How can stem cells divide?
a) symmetric self-renewal
–> two copies of stem cells
b) asymmetric self-renewal
–> 1 stem cell + 1 differentiated cell
c) symmetric differentiation
–> 2 identical differentiated cells
What are embryonic stem cells made of?
pluripotent stem cells removed from embryo and cultured in dish
Yamanaka factors include?
Myc, Oct, Sox, Klf
How are iPS generated?
intro four yamanaka factors into adult cells
–> programmed into a stem cell state
How can you describe adult stem cells in terms of potency?
multipotent
types of stem cells present in adults
i) epidermal stem cells
ii) hematopoietic stem cells
iii) Mesenchymal stem cells
iv) neural stem cells
v) intestinal stem cells
where is mesenchymal stem cells found?
bone marrow
what does mesenchymal stem cells make?
fat, cartilage and bond cells
types of stem cell transplantation
i) autologous (use their own stem cells)
ii) allogenic (related or universal donor after editing)
source of cells for stem cell transplant
i) immortalized NSC
ii) primary NSC
iii) iPSC derived
iv) ESC derived
how does endogenous recruitment work?
activate adult stem cells within us after injury/disease to replace lost cells
issues with stem cell recruitment?
i) respond isn’t robust or long lasting
ii) new cells have poor survival
iii) not sure how to specify the production of one cell type
iv) lack understanding in signals to recruit or activate NSC
Pros of stem cell tourism
i) individuals hv terminal diseases
ii) often feel like ther’s no option
iii)media reporting miracle response
iv) lots of potential exist for transformative treatment
Con for stem cell tourism
i) can make pathology worse
ii) erode public trust
iii) therapy not tested in clinical trial
iv) massive cost
v) poor regulation
Difference between neocortex structure of mice and human
i) higher percentage in mass of brain of human compared to mice
ii) mice lack folding (lissencephalic), human has lots of folding (gyrencephalic)
iii) more neurons present in neocortex of human compared to mice
types of neurons present (in terms of function)
i) excitatory neurons (glutamatergic)
– release glutamate to excite neurons
ii) inhibitory neurons (GABAergic)
– release GABA to inhibit neurons
what does excitatory neurons release?
glutamate
What does inhibitory neurons release?
GABA
Function for neocortex
higher order cognitive and sensimotor processing
Function of corpus callosum
axon bundles connecting left and right hemisphere
Basal ganglia function
voluntary movement
hypothalamus function
control hormone secretion and other autonomic function
thalamus function
transmits sensory info to cortex
lateral ventricle
fluid filled cavities of ventricular system in centre of CNS
What are the three germ layers?
i) ectoderm
ii) mesoderm
iii) endoderm
What does ectoderm give rise to?
nervous system + skin
What does mesoderm give rise to?
muscle and skeleton
What does endoderm giver rise to?
gut, associated organs
What does rostral end of neutral tube develop into?
brain
What does caudal end of neutral tube develop into?
spinal cord
Sequence of neural tube closure
i) hindbrain/cervical
ii) forebrain/midbrain
iii) rostral end of forebrain
What happens to forebrain in 5 vesicle stage?
telencephalon + diencephalon
WHat happens to hindbrain in 5 vesicle stage?
develop into myelencephalon, metencephalon
What happens to midbrain in 5 vesicle stage?
stays the same
what flexures are found during neural tube expansion?
i) Cephalic flexure
ii) Cervical flexure
iii) pontine flexure
Where does cephalic flexure occur?
mid and hindbrain
Where does cervical flexure occur
hindbrain and spinal cord
where does pontine flexure occur?
metencephalon, myelencephalon
anatomy of neocortex in embryo (from bottom to top)
i) ventricular zone
ii) subventricular zone
iii) intermediate zone
iv) cortical plate
What is found in ventricular zone?
radial precursors
What is found in sub-ventricular zone?
intermediate precursors forming neurons
What is found in intermediate zone?
new neurons migrate
cortical plate what is found
final destination for new born neurons
What happens after radial progenitors start to form?
i) form neurons (startgin E12)
ii) form glial cells (start around E18)
