Stem Cells- Part II-March 24 (1) (1)

Question 1

What are the learning objectives related to tissue-specific stem cells?

Answer 1

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.

Question 2

Name some examples of tissue-specific stem cells.

Answer 2

• Hematopoietic stem cells
• Intestinal stem cells
• Mesenchymal stem cells
• Epidermal stem cells
• Hair follicle stem cells
• Spermatogonial stem cells
• Neural stem cells

Question 3

What do hematopoietic stem cells (HSCs) generate?

Answer 3

All cell types that form the blood and the immune system.

Question 4

What is the significance of markers in distinguishing HSCs?

Answer 4

No single surface marker is ideal to distinguish HSCs from progenitor and differentiated blood/immune cells.

Question 5

What technique is used to sort and purify HSCs based on their fluorescence?

Answer 5

Fluorescence-Activated Cell Sorter (FACS).

Question 6

What is an example of a combination of markers for purifying human HSCs?

Answer 6

CD34+/CD38–/CD45RA–/CD10–.

Question 7

What happens during in vivo transplantation studies of HSCs?

Answer 7

HSCs are isolated and transplanted into an irradiated mouse, restoring all types of blood and immune cells.

Question 8

What is the role of Paneth cells in the intestinal epithelium?

Answer 8

Produce lysozymes to kill bacteria.

Question 9

Where are intestinal stem cells (ISCs) primarily located?

Answer 9

At the base of the crypt in the small intestine.

Question 10

What is the function of the LGR5 marker in intestinal stem cells?

Answer 10

LGR5 is a co-receptor for Wnt factors and responds to R-spondin signals.

Question 11

What types of cells can mesenchymal stem cells (MSCs) differentiate into?

Answer 11

• Osteoblasts (bone)
• Chondrocytes (cartilage)
• Adipocytes (adipose tissue/fat)

Question 12

What are the markers of mesenchymal stem cells (MSCs)?

Answer 12

• CD73
• CD105

Question 13

True or False: The ability of MSCs to form different cell types distinguishes them from fibroblasts.

Answer 13

True.

Question 14

What is the continuous turnover period of the epidermis in humans?

Answer 14

Approximately 1 month.

Question 15

What cell type is expressed in the basal layer of the epidermis and is a marker for stem cells?

Answer 15

Axin2.

Question 16

Fill in the blank: The primary source of adult HSCs is _______.

Answer 16

bone marrow.

Question 17

What type of cells are keratinocytes?

Answer 17

Squamous epithelial cells that produce keratin.

Question 18

What happens to progenitor cells as they leave the crypt in the small intestine?

Answer 18

They differentiate and migrate up the villi.

Question 19

What is the role of the hypoxia-inducible factor (HIF) in the HSC niche?

Answer 19

Supports HSCs in their niche.

Question 20

Where else besides bone marrow can HSCs be found?

Answer 20

In the spleen and liver.

Question 21

What type of cells can epidermal stem cells differentiate into?

Answer 21

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.

Question 22

Where are hair follicle stem cells located?

Answer 22

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.

Question 23

What are the phases of the hair follicle cycle?

Answer 23

Anagen, catagen, and telogen

Anagen is the growth phase, catagen is the regression phase, and telogen is the resting phase.

Question 24

What happens during the catagen phase of the hair follicle cycle?

Answer 24

The lower part of the hair follicle undergoes apoptosis

This allows the bulge region to come in contact with the dermal papilla.

Question 25

What signals does the dermal papilla provide for hair follicle stem cells?

Answer 25

FGF7, BMP, and Wnt signals ## Footnote These signals are essential for the growth and differentiation of hair follicle stem cells.

Question 26

What are some markers for hair follicle stem cells?

Answer 26

CD34, K14, K19, SOX9, LGR5, P-Cadherin ## Footnote These markers are used to identify hair follicle stem cells.

Question 27

What type of cells are spermatogonial stem cells (SSCs)?

Answer 27

Type A single spermatogonial cells ## Footnote SSCs are involved in the development of mature spermatozoa.

Question 28

Where are spermatogonial stem cells found?

Answer 28

In the testis ## Footnote They are part of the tissue-specific stem cell system.

Question 29

What is the role of Sertoli cells in relation to spermatogonial stem cells?

Answer 29

They are essential for SSC survival and differentiation ## Footnote Sertoli cells secrete GDNF and FGF to support SSC.

Question 30

What do Leydig cells provide to support spermatogonial stem cells?

Answer 30

Colony-Stimulating Factor 1 (CSF1) ## Footnote CSF1 supports the self-renewal of spermatogonial stem cells.

Question 31

What are neural crest cells (NCCs)?

Answer 31

A population of cells present in vertebrate embryos ## Footnote NCCs appear between the dorsal ectoderm and neural tube.

Question 32

What derivatives do cranial neural crest cells give rise to?

Answer 32

Bones and cartilage of the head and face, nerve ganglia, smooth muscle, connective tissue, and pigment cells ## Footnote Cranial NCCs contribute to various structures in the head and face.

Question 33

What is the function of cardiac neural crest cells?

Answer 33

Heart development ## Footnote Cardiac NCCs play a crucial role in the formation of the heart.

Question 34

What do trunk neural crest cells form?

Answer 34

Peripheral nervous system (neurons and glial cells) ## Footnote Trunk NCCs are responsible for forming components of the peripheral nervous system.

Question 35

Where are proliferating neural stem cells (NSCs) found in rodents?

Answer 35

In the subventricular zone of the lateral ventricles and the dentate gyrus of the hippocampus ## Footnote These regions are known for ongoing neurogenesis.

Question 36

What can neural stem cells give rise to?

Answer 36

Neurons, astrocytes, and oligodendrocytes ## Footnote NSCs have the potential to differentiate into various types of neural cells.