Stem Cells Gilbert Chapter 5

What is the corcern of IPSCs beta cells

Immune rejection or diabetes-mediated immune attack.

Embryonic cells at an early stage are referred to as?

Blastocycts - inner cell mass

What regulates stem cell division?

Cell to Cell communication Mitotic spindle Proteins act as signaling factors biomechanical stress (cells will serve to secrete paracrine factors, or growth factors) neural signals in the niche

________ is the restoration of tissues using healthy cells derived from various types of stem cells, which are now used in _______engineering.

Cell-Replacement therapy tissue

Which of the following is NOT associated with terminal differentiation?

Differentiated cells are highly proliferative

Stem cells cannot generate what?

Extraembryonic tissues at least as we now it now

Slide 1-27 summary (part 2)

From multipotent stem cells, those will oftentimes operate through progenitor cells, those progenitor cells will also continue to divide and proliferate for a reduced period of time, sort of in a transient way, leading to the creation of multiple cell types that will then go on and mature into differentiated cells. So from your progenitor cell, you can give rise to precursor cells. That term, precursor cell, is often used but those cells typically are not dividing but are sort of an immature state leading to that differentiated cell type as illustrated here.

________ are embryonic stem-cell like cells that were produced from the reprogramming of adult: differentiated cells by introducing four pluripotency genes-Oct4, Sox2, Kfl4, and c-MYc- which encode________

Induced pluripotent stem cell transcription factor

What determines if the cell divides asymmetrical or symmetrical?

Mitotic spindle (plane in which the mitotic spindle orientates)

Multipotent

Multipotent stem cells are cells that have the capacity to self-renew by dividing and to develop into multiple specialized cell types present in a specific tissue or organ. Most *adult stem or somatic cells *are multipotent stem cells

Induced Pluripotent Stem Cells

One of the most important stem cell types IPSCs possess the same functional capabilities as embryonic stem cells but are actually derived from a re-programmed, differentiated cell type.

What stem cells could be used to cure type 1 diabetes?

Patient-specific beta cells from iPSCs The iPSC derived beta cells can be successfully introduced into a type 1 diabetes immunodeficient mouse model, and this appears to rescue insulin production and successful metabolism of glucose.

Mature progenitor cells transition into ...

Precursor cells until they develop into the differentiated cell type

While the induction of stem cells and differentiation of specific cell type progenitors in the lab has obvious applications to regenerative medicine (e.g., cell replacement therapy), there are potential negative health outcomes to such therapies, such as...

Production of cancers, such as teratomas

Example of a unipotent cell

Spermatogonia unipotent stem cells function in the organism to generate only one cell type

Which of the following cocktails of transcription factors, aka Yamanaka factors, can be used to generate iPS cells? a) Oct4, Nanog, Smad, and Cdx2 b) Gata4, Nanog, Gli, and Cdx2 c) Oct4, Nanog, Sox2, and Myc d) OCt4, Sox2, Gata4, and Rb

c) Oct4, Nanog, Sox2, and Myc

From which group of cells are embryonic stem cells derived? a. trophectoderm b. primitive endoderm c. extraembryonic ectoderm d. inner cell mass

d. inner cell mass Ans: D

Which of the following cells would be considered differentiated? a. blastomere b. spemann organizer c. myotome of the somite d. muscle cell e. stem cell

d. muscle cell

What are the 3 germ layers?

ectoderm, mesoderm, endoderm all can be derived from stem cells

Stems hold the funtional potential to

give rise to an array of cell types, even the entire embryo and everything needed to generate a multi-cellular organism.

Where do stem cells develop?

inner cell mass

What does it meant by *quiescent*?

is the reversible state of a cell in which it does not divide but retains the ability to re-enter cell proliferation. Some adult stem cells are maintained in a quiescent state and can be rapidly activated when stimulated, for example by injury to the tissue in which they reside

Cell to cell communication

mitogenic signals promote proliferation. Signals from the environment will be interpreted and received by that stem cell and those will provide the instructions to undergo division and start to divide.

Slide 1-2 7Summary (part 1)

potency, or the potential that these different stem cells have to develop into different things. The first one in the series of course, is the totipotent cell, or in this case, really just the zygote. That single-cell zygote has and retains the ability to generate everything necessary to produce an organism - the embryo proper, as well as all extraembryonic lineages. Then we move down the potential scale to pluripotent. The only cell type there is the embryonic stem cell. Resides in the inner mass of the blastocyst, and it can generate all the cell types of the three different germ layers that make up the embryo. During development, it will create a series of multipotent stem cells associated with every tissue and organ. These multipotent stem cells can still divide, but have more lineage restricted ability to the cell types that can differentiate.

Type 1 Diabetes

the immune system specifically attacks pancreatic beta Islet cells. These cells function to secrete insulin. Insulin is needed to breakdown sugars.The cause of diabetes is unknown. Stem cells offer the potential to treat and perhaps even cure a variety of diseases such as diabetes.

What is meant by potency?

the power to produce different types of differentiated stem cells

how do you develop monozygotic twins?

when the inner cell mass splits into 2

Symmetrical differentiation

both daughters cells become specified and differentiated *benefit is it increases the stem cell pool

What happens if mutation of proliferating stem cells occur?

greater levels of proliferation or rates of division or inability to remain quiescent, well then you run the risk of *tumor formation and ultimately cancer.*

Only natural occurring stem cell considered pluripotent

Embryonic stem cells

How do we approach IPSCs beta cells

Reprogram exocrine to endocrine beta cells.•Make patient-specific induced beta cells. •Transplant back into patient.

_________ is a tumor derived from embryonic stem cells

Teratocarcinoma

Totipotent vs pluripotent vs multipotent

Totipotent cells can *form all the cell types in a body,* plus the extraembryonic, or placental, cells. Embryonic cells within the first couple of cell divisions after fertilization are the only cells that are totipotent. Pluripotent cells can give *rise to all of the cell types that make up the body* (mesoderm ectoderm endoderm); ---embryonic stem cells Multipotent cells-function to generate cell types with restricted specificity for the tissue in which they reside-- adult stem cells

Stem cell niche

an area of a tissue that provides a specific microenvironment, in which stem cells are present in an undifferentiated and self-renewable state.

Where are stem cells that renew the epithelium of the gut found? a. in the bone marrow b. in the inner cell mass c. near the bottom of the crypt

c. near the bottom of the crypt

Multipotent stem cells reside

with specific organs or tissues **the progeny they generate are restricted to those organs

Totipotency

"capable of all" stem cells to form all structures of an organism ~ principal aspects of the organism are the embryo itself and the supportive material (extraembryonic tissue)

Pluripotency

"capable of many things" A single pluripotent stem cell has the ability to give rise to different types of cells that develop from the 3 germ layers, from which all the cells of the body arise Eg inner mass cells, embryonic cells, germ cells and germ cell tumors (Teratocarcinoma)

progenitor cells/transit amplifying cells

(divide while migrating) undifferentiated cells that have the capacity to divide a few times before differentiating: unlike stem cells they are not capable of unlimited self-renewal

What ideas support that embryonic stem cells are pluripotent and generate needs of the embryo

*monozygotic twins* *tumors*:seen when these cells were transplanted in a mouse( cell types and tissues derived, and representative of all three germ layers - ectoderm, mesoderm, and endoderm)

How do you classify a stem cell?

1. Stem cells are generally regarded as *undifferentiated or unspecified and as such retain the ability to divide* 2. Upon division they have the ability to *self-renew* 3. upon division, the *daughter cells* can go on to *mature*, and *differentiate into a variety of cell types, depending on the stem cell and tissue type of origin.*

Benefits of IPSCs

1. potentially patient-specific therapies 2. study and cure human diseases 3. regenerate whole organs

Asymmetric self-renewing

A stem cells generates two daughter cells. The daughter cells can divide and make two more daughter cells. However one of those daughter cells may begin to become specified and start to mature along a differentiative path, whereas the other one remains as a self-renewing division Nutshell: one daughter cell generates another stem cell and the other daughter goes on to differentiate eg into a neuron

Which of the following surrounds a stem cell and maintains its proliferative state and self-renewal capabilities? a. stem-cell niche b. stem-cell milieu c. stem-cell marrow d. stem-cell complex

A. stem-cell niche

What is the role of stem cells with regard to the function of adult tissues and organs?

ANS: will differentiate to replace damaged and worn out cells in the adult tissue or organ

Embryonic stem cells vs adult stem cells

Adult stem cells are considered to have a shorter lifespan whereas embryonic stem cells will seemingly divide and proliferate indefinitely