Stem Cells and Neurogenesis Flashcards

Define the properties of stem cells Describe the similarities and differences between pluripotent and tissue-specific stem cells Discuss the importance of pluripotent cells in neuroscience Define the properties and localisation of neural stem cells in the CNS Discuss how neural stem cells are temporally and spatially regulated during development

1
Q

What are stem cells?

A

Unspecified cells which can either differentiate into specialised cell types or self-renew - divide to create two daughter cells, at least one of which is equivalent to the parent cell

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2
Q

Define totipotency, and give an example

A

The ability of a cell to form an entire organism

Example: zygote

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3
Q

Define pluripotency

A

The ability of a cell to form all the body’s cell lineages, including germ cells, but which cannot form an entire organism due to an inability to generate the placenta

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4
Q

Define multipotency

A

The ability of a cell to form multiple cell types, constituting an entire tissue or tissues, but only in one cell lineage

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5
Q

Name the three embryonic germ cell layers

A

Ectoderm, mesoderm, and endoderm

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6
Q

Which lineage forms neural lineages and skin cells?

A

Ectoderm

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7
Q

Which germ cell lineage forms bone, muscle, and blood cells?

A

Mesoderm

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8
Q

Describe the stages after a sperm has fertilised an egg

A

This forms a zygote, which then becomes a blastocyst. The blastocyst undergoes implantation, then gastrulation, before differentiating into the ectoderm, mesoderm, endoderm, and germ cells

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9
Q

Which four transcription factors are given to human cells to turn them into induced pluripotent stem cells?

A

Oct4, Sox2, Klf4, and c-Myc

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10
Q

How are embryonic stem cells obtained?

A

They are isolated from the inner cell mass of the pre-implantation blastocyst and cultured

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11
Q

Which intrinsic transcription factors maintain pluripotency in stem cells?

A

Oct4, Sox2, and Nanog

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12
Q

How is pluripotency assessed?

A

Pluripotent stem cells are aggregated in a culture disc to form embryoid bodies, then plated to detect the three different differentiation markers - AFP for endoderm, mActin for mesoderm, and beta-TubIII for ectoderm

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13
Q

How are mouse pluripotent stem cells assessed?

A

Chimera formation. Pluripotent stem cells are injected into a blastocyst from a different strain of mouse, then transplanted into a mouse of the same strain as the original mouse to act as a surrogate mother. The resultant offspring should have the characteristics of both mice down to their germ cells

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14
Q

Where are haematopoeitic stem cells found?

A

Short-term cells are found close to blood capillaries, and long-term cells close to the osteoblasts

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15
Q

Where are intestinal stem cells found?

A

The bottom of intestinal crypts

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16
Q

How are somatic stem cells different to pluripotent stem cells?

A

They have limited, niche-dependent self-renewal capacity, and cannot form teratomas as they lack sufficient plasticity. They also exist in vivo and exhibit limited growth in vitro, whereas pluripotent stem cells do not exist in vivo

17
Q

What is a stem cell niche?

A

The microenvironment which surrounds and nurtures the stem cells, enabling them to maintain tissue homeostasis

18
Q

Which develops first in culture of neural cells, neurons or glia?

A

Neurons

19
Q

What are the advantages of somatic stem cells for cell therapy?

A

Autologous so low rejection risk, low risk of tumour growth, few ethical issues

20
Q

What are the disadvantages of somatic stem cells for cell therapy?

A

Limited growth and accessibility, limited differentiation potency

21
Q

What are the advantages of pluripotent stem cells for cell therapy?

A

Can be expanded to a large number of cells, capable of generating all cell types

22
Q

What are the challenges of pluripotent stem cell use in cell therapy?

A

Not all control signals for differentiation are understood, integration and survival, tumourigenesis, ethical issues of embryonic stem cells, immune rejection of embryonic stem cells

23
Q

At what stage are pluripotent stem cells for neurogenesis currently transplanted?

A

As neural progenitors