Growth, post-embryonic development and regeneration

Question 1

Approaches for cell-replacement therapies

Answer 1

1. ESCs
2. ASCs
3. iPSCs
4. Transdifferentiation
   (All make differentiated cells)

Question 2

Type 1 diabetes

Answer 2

1. pancreas 
–β-cells destroyed
–no stem cells
2. No insulin
3. Cells from cadavers scarce, rejection, disease

Question 3

A cure for type 1 diabetes?

Answer 3

A treatment using stem cells that produce insulin has surprised experts and given them hope for 1.5 million Americans living with the disease

Question 4

Embryonic development

Answer 4

Basic form & pattern

Question 5

Post-embryonic development

Answer 5

Growth increases with size

Question 6

Metamorphosis

Answer 6

Larva turns into an adult where old organs disappear & new organs appear

Question 7

Regeneration

Answer 7

Juvenile or adult replace tissue/organ

Question 8

Growth

Answer 8

Increases in size or mass, where post-embryonic stage determines organ size & body size

Question 9

Proliferation

Answer 9

1. Mitosis

2. Net growth - Mitosis vs apoptosis

Question 10

Enlargement

Answer 10

1. Hypertrophy

2. Mammals (heart, kidney, nerves )

Question 11

Accretion

Answer 11

Increase extracellular space secrete ECM bone, cartilage

Question 12

Proliferation control

Answer 12

Cyclins check point proteins

Question 13

Proliferation & cancer

Answer 13

1. Mutation in cell division genes
2. 85% cancer in epithelia (gut, skin, etc., have stem cells)
3. stem cell division (tight regulation, mutations → uncontrolled division)
4. tumor progression (accumulate many mutations, pancreatic cancer
   has 63 mutations in proliferation genes

Question 14

Tadpole turning a frog

Answer 14

Tadpole has a tail but losses tail to turn into a frog (apoptosis), tadpole also has no limbs but gains limbs when turn into a frog (metamorphosis)

Question 15

Amphibian metamorphosis

Answer 15

1. Environmental cues then act on hypothalamus, pituitary gland then thyroid then metamorphosis
2. Thyroid hormone different effects where limb increase cell growth & tail decrease cell growth

Question 16

Regeneration with amphibians

Answer 16

Adults maintenance where if they get injured, they just repair & replace.

Question 17

Regeneration occurs at a faster rate when younger than it goes when older why?

Answer 17

Because have more stem cells to replace injury when younger than when your older

Question 18

Regeneration with invertebrates

Answer 18

Some invertebrates have asexual reproduction where they can regenerate themselves (have mitosis but no meiosis), they can go from a fragment into a whole animal

Question 19

Morphallaxis regeneration

Answer 19

1. No new cells initially

2. Existing cells reorganize then divide after

Question 20

Epimorphosis regeneration

Answer 20

New cells immediately from mitosis

Question 21

Describe the process of limb regeneration for frogs

Answer 21

1. Amputations
2. Healing- epithelium covers wound
3. Dedifferentiation - mature become immature cells
4. Proliferation- Cone stage
5. Redifferentiation- immature cells become mature cells

Question 22

Blastema

Answer 22

Stem cells that can be multipotent or lineage restricted, it is also mostly lineage specific

Question 23

Amphibian limb: epimorphosis

Answer 23

1. Macrophages necessary
   (dedifferentiation)
2. No macrophages (no regeneration)

Question 24

Heart regeneration

Answer 24

Was tested in adult zebra fish, where after 20% injury some grow back, the origin of the new tissue used to come from stem cells but now it comes from differential cells

Question 25

How does heart regeneration occur with zebra fish?

Answer 25

An injury happens & cardiomyocytes dedifferentiation divide redifferentiation leads to new cardiomyocytes functional integration within 4 weeks

Question 26

Heart regeneration with adult mouse

Answer 26

1. After birth small heart turns into a large heart (hypertrophy occurs not mitosis)
2. Injury leads to a scar where no regeneration occurs meiosis 1 happens not mitosis, where therapy decrease meiosis 1 but increase regeneration

Question 27

Heart regeneration on embryo mouse

Answer 27

1. Up to 7 days old can regenerate
   15% injury
2. differentiation cardiomyocytes leads to dedifferentiation like zebrafish (good model)

Question 28

Kidney regeneration in adult zebra fish

Answer 28

Ihx1a same as RTF