Stem Cells- Part II-March 24 (1) (1) Flashcards
What are the learning objectives related to tissue-specific stem cells?
Identify the source and lineage differentiation of tissue-specific stem cells, identify specific markers of tissue-specific stem cells, describe the niche signaling for tissue-specific stem cells.
Name some examples of tissue-specific stem cells.
- Hematopoietic stem cells
- Intestinal stem cells
- Mesenchymal stem cells
- Epidermal stem cells
- Hair follicle stem cells
- Spermatogonial stem cells
- Neural stem cells
What do hematopoietic stem cells (HSCs) generate?
All cell types that form the blood and the immune system.
What is the significance of markers in distinguishing HSCs?
No single surface marker is ideal to distinguish HSCs from progenitor and differentiated blood/immune cells.
What technique is used to sort and purify HSCs based on their fluorescence?
Fluorescence-Activated Cell Sorter (FACS).
What is an example of a combination of markers for purifying human HSCs?
CD34+/CD38–/CD45RA–/CD10–.
What happens during in vivo transplantation studies of HSCs?
HSCs are isolated and transplanted into an irradiated mouse, restoring all types of blood and immune cells.
What is the role of Paneth cells in the intestinal epithelium?
Produce lysozymes to kill bacteria.
Where are intestinal stem cells (ISCs) primarily located?
At the base of the crypt in the small intestine.
What is the function of the LGR5 marker in intestinal stem cells?
LGR5 is a co-receptor for Wnt factors and responds to R-spondin signals.
What types of cells can mesenchymal stem cells (MSCs) differentiate into?
- Osteoblasts (bone)
- Chondrocytes (cartilage)
- Adipocytes (adipose tissue/fat)
What are the markers of mesenchymal stem cells (MSCs)?
- CD73
- CD105
True or False: The ability of MSCs to form different cell types distinguishes them from fibroblasts.
True.
What is the continuous turnover period of the epidermis in humans?
Approximately 1 month.
What cell type is expressed in the basal layer of the epidermis and is a marker for stem cells?
Axin2.
Fill in the blank: The primary source of adult HSCs is _______.
bone marrow.
What type of cells are keratinocytes?
Squamous epithelial cells that produce keratin.
What happens to progenitor cells as they leave the crypt in the small intestine?
They differentiate and migrate up the villi.
What is the role of the hypoxia-inducible factor (HIF) in the HSC niche?
Supports HSCs in their niche.
Where else besides bone marrow can HSCs be found?
In the spleen and liver.
What type of cells can epidermal stem cells differentiate into?
Merkel cells, melanocytes, and Langerhans cells
Merkel cells are mechanoreceptor cells, melanocytes are derived from neural crest cells, and Langerhans cells are derived from hematopoietic stem cells.
Where are hair follicle stem cells located?
In the bulge, away from the dermal papilla
The dermal papilla is at the base of the hair follicle and forms the niche for hair follicle stem cells.
What are the phases of the hair follicle cycle?
Anagen, catagen, and telogen
Anagen is the growth phase, catagen is the regression phase, and telogen is the resting phase.
What happens during the catagen phase of the hair follicle cycle?
The lower part of the hair follicle undergoes apoptosis
This allows the bulge region to come in contact with the dermal papilla.
What signals does the dermal papilla provide for hair follicle stem cells?
FGF7, BMP, and Wnt signals
These signals are essential for the growth and differentiation of hair follicle stem cells.
What are some markers for hair follicle stem cells?
CD34, K14, K19, SOX9, LGR5, P-Cadherin
These markers are used to identify hair follicle stem cells.
What type of cells are spermatogonial stem cells (SSCs)?
Type A single spermatogonial cells
SSCs are involved in the development of mature spermatozoa.
Where are spermatogonial stem cells found?
In the testis
They are part of the tissue-specific stem cell system.
What is the role of Sertoli cells in relation to spermatogonial stem cells?
They are essential for SSC survival and differentiation
Sertoli cells secrete GDNF and FGF to support SSC.
What do Leydig cells provide to support spermatogonial stem cells?
Colony-Stimulating Factor 1 (CSF1)
CSF1 supports the self-renewal of spermatogonial stem cells.
What are neural crest cells (NCCs)?
A population of cells present in vertebrate embryos
NCCs appear between the dorsal ectoderm and neural tube.
What derivatives do cranial neural crest cells give rise to?
Bones and cartilage of the head and face, nerve ganglia, smooth muscle, connective tissue, and pigment cells
Cranial NCCs contribute to various structures in the head and face.
What is the function of cardiac neural crest cells?
Heart development
Cardiac NCCs play a crucial role in the formation of the heart.
What do trunk neural crest cells form?
Peripheral nervous system (neurons and glial cells)
Trunk NCCs are responsible for forming components of the peripheral nervous system.
Where are proliferating neural stem cells (NSCs) found in rodents?
In the subventricular zone of the lateral ventricles and the dentate gyrus of the hippocampus
These regions are known for ongoing neurogenesis.
What can neural stem cells give rise to?
Neurons, astrocytes, and oligodendrocytes
NSCs have the potential to differentiate into various types of neural cells.
