Cellular Differentiation Flashcards
What can these types of embryonic stem cells differentiate into?
Totipotent, Pluripotent, Multipotent
Totipotent- can turn into embryonic or extra embryonic tissue, fertalized ovum and first few divisions
Pluripotent- can turn into any germ layer; mesoderm, ectoderm, endoderm. THIS one is “stem cells”
Multipotent- can only turn into a limited number of cell types arising from one germ layer. Adult and cord blood cells
Which Go cells can return to cell cycle?
What do they need to be able to do that?
fibroblasts, endothelial, and liver epithelial.
Need signal: mitogen or Growth Factor
In which state are adult stem cell?
Multipotent- can give rise to only a limited amount of cell types
There is a balance of proliferating and death. Don’t want too much of either
What is a subpopulation and where do you find it?
How do they divide?
A group of multipotent cells in adult to regenerate lost cells.
Found in basal layer of a tissue.
The cell replicates > one goes on to rapidly divide/differentiate > transient amplifying cell (intermediate) > cell
Niche
Microenvironment for subpopulations
Provides the signals needed to maintain stem cells.
What is Wnts signaling
secreted by fibroblasts under GI crypt.
part of maintenance for stem cell sub pop in GI
example of signal from a niche
How do transcription factors and epigenetics play a role in differentiation?
All cells have the same genome. Specific TF and chromatin remodeling allow the cells to express the genes that need to be expressed for that certain cell.
What are the two major transcription factors that ensure the self-renewal and pluripotency of embryonic stem cells?
How does epigenetics affect them?
OCT4, SOX 2
Methylation of genes for OCT4 and SOX2 lead to differentiation.
What do keratinocytes do and what layers do they go into?
Stem cells of epidermis
Basal cells- stem cells, attached to basal lamina
Prickle cells- stratum spinosum, lots of desmosomes
Granular Cells- granular layer, waterproof barrier, fill with keratin
Squames- dying terminally differentiate cells fill with keratin
what are the Keratinocyte signals and what do they tell the cell to do?
Integrin- stay a basal keratinocyte (stem cell)
Notch- produce transit amplifying cells
Hedgehog- Produce sebaccous gland cells
Wnt- Produce hair follicle cells
What type of cells do adipocytes derive from?
Which transcription factor initiates triglyceride storage?
Mesodermal- mesenchymal
PPARy- acts like steroid receptor, heterodimerizes with RXR
What is the difference between a lipoblast and a lipocyte?
Both part of adipose tissue.
lipoblasts- Increasing lipid inclusions see
Lipocyte- mature cell, one large lipid filled inclusion, eccentric nucleus (on edge of cell), spherical shape, chicken-wire in H&E)
White vs Brown Adidose tissue
White- found in adults, 10% or more of body weight, triglyceride storage and endocrine secretions
Brown- during fetal development, lost during childhood, some around organs, thermogenic
Transdifferentiation of adipose
Differentiation with no cell division
White to brown adipose- induced by cold temp, chronic exercise, ‘browning phenomenon’
Brown to white- caloric excess
What are Chondrocytes and describe chondrogenesis?
What is the transcription factor that regulates the synthesis?
cartilage producing cells
Chrondroblasts (stem cells), mesenchymal
– secrete collagen based ECM matrix which remains in adult cartilage
SOX-9 induces cells to secrete collagen based matrix
Mature chondrocytes when completely surrounded
AVASCULAR, limited ability to repair
Hayline cartilage
What helps hold it together?
basic form found throughout the body
Chondrocytes are in lacunae
Collagen, GAG, proteoglycans, and adhesive glycoproteins help hold it together
Isogenous groups
groups of cells that appear in clusters because they recently divided